lt2662_RubberBondGuide

Table Of Contents Page Number

Introduction 1 Description Of Adhesives 2

• Cyanoacrylate Adhesives 2• Light Curing Acrylic Adhesives 3• Polyurethane Adhesives 4• Two-Part No-Mix Acrylic Adhesives 5• Silicone Adhesives 6• Why Bond Elastomers with Loctite Adhesives? 7

How To Use The Rubber and TPE Bonding Chapters 9How to Use The Adhesive Shear Strength Table 10Rubber and TPE Bonding Chapters 12

• Butyl Rubber (IIR) 12• Chlorosulfonated Polyethylene (CSM) 14• Copolyester TPE 16• Epichlorohydrin Rubber (CO, ECO, GCO, GECO) 18• Ethylene Acrylic Rubber (EEA) 20• Ethylene Propylene Rubber (EPM, EPDM) 22• Ethylene-Vinyl Acetate Copolymer (EVA) 24• Fluorocarbon Rubber (FKM) 26• Fluorosilicone Rubber (FVMQ) 28• Halogenated Butyl Rubber (BIIR, CIIR) 30• Hydrogenated Nitrile Rubber (H-NBR, HSN) 32• Melt Processible Rubber (MPR) 34• Natural Rubber (NR) 36• Neoprene Rubber (CR) 38• Nitrile Rubber (NBR, XNBR) 40• Polyacrylate Rubber (ACM) 42• Polyisoprene Rubber (IR) 44• Polyolefin Elastomers (POE) 46• Poly(propylene oxide) Rubber (GPO) 48• Polysulfide Rubber (TM) 50• Silicone-Modified EPDM 52• Silicone Rubber (MQ, VMQ, PMQ, PVMQ) 54• Styrene-Butadiene Rubber (SBR) 56• Styrenic TPE (S-B-S, S-I-S, S-EB-S) 58• Thermoplastic Vulcanizates (TPV) 60

Test Methodology 62Index of Trade Names 66Acknowledgements 69Disclaimer 70

The Loctite Design Guide for Bonding Rubbers and TPEs


The ProblemFrom the discovery of natural rubber to the develop-ment of modern day thermoplastic elastomers(TPEs), elastomeric materials have found a widevariety of uses that make them an integral part ofan industrial society. In a diverse variety of prod-ucts ranging from automobile tires to lifesavingimplantable medical devices, their unique ability tobe greatly deformed and return to their originalshape fills an important niche in the world of engi-neering materials. It would be difficult to identify amanufacturing process which does not use elas-tomers in one form or another.

Elastomeric materials have achieved widespreadacceptance due to the virtually limitless combina-tions of elastomer types, fillers and additives whichcan be compounded at relatively low costs andprocessed by a wide variety of methods. This givesend-users the ability to develop specific formula-tions with properties tailored to their needs. Byproperly selecting the base elastomer, additives andfillers, as well as the appropriate cure method, thephysical, chemical and thermal properties of anelastomer can be made to meet or exceed the per-formance requirements of almost any applicationrequiring elastomeric properties.

However, while the limitless variety of elastomers isan invaluable asset to a designer selecting an elas-tomer, it is the designer's biggest limitation whenselecting an adhesive. The countless adhesivesavailable, coupled with the virtually limitless elas-tomer formulations possible, make it highly unlikelythat there will be bond strength data for the specificadhesive/elastomer combination in the designer'sapplication.

The SolutionBond Strength InformationThis guide is designed to indicate the bondability ofthe 25 most commonly used families of elastomers.This was accomplished using two approaches. Themajority of elastomers which were evaluated werecompounded specifically to determine the effect dif-ferent additives and fillers had on the bondability ofthese materials. Once the designer identifies theelastomer formulations containing the same fillersand additives that he desires to bond, he can then

pinpoint the adhesives which performed best on thosematerials. Although this will probably not tell the designerthe exact bond strength that will be achieved by that spe-cific adhesive on that specific material, it will give thedesigner a general idea of what bond strengths can beachieved. For the other elastomers, bond strength testingwas performed on commercially available grades whichwere selected to represent each major category of theelastomer based on the major end-use applications, and/orthe chemical structure of that elastomer.

Adhesive InformationAn adhesive cannot be selected for an application solely onthe basis of bond strength information. Other factors suchas the cure speed, environmental resistance, thermal resis-tance and suitability for automation will play a critical rolein determining the best adhesive for a specific application.To give a designer insight into these design parameters, anin-depth description of the five adhesive types most com-monly used for bonding elastomers has been included inthis guide. The five adhesive types discussed were cyano-acrylates, two-part no-mix acrylics, light curing acrylics, sili-cones and polyurethanes. These adhesive sections containa general description, a detailed discussion of the chemicalstructure and cure mechanism, and a listing of the benefitsand limitations of each adhesive.

Elastomer InformationManufacturers may have the flexibility to select the elas-tomers which are best suited for their applications in termsof performance and bondability. To aid the designer, an in-depth discussion of each of the elastomer types is includ-ed. Information covered includes a general description ofthe elastomer and its properties, as well as a list of tradenames, suppliers and typical applications.

Cure Process EffectsFor thermoset rubbers, the ultimate bond strength might beimproved by stopping the vulcanization process before allcrosslinking sites available have been consumed. Stoppingthe vulcanization process before the rubber has achievedits ultimate modulus will leave unreacted crosslinking siteson the rubber backbone and form a polymer with a lowercrosslink density. As a result, the unreacted crosslinkingsites may improve bond strength by reacting with theadhesive. In addition, the lower crosslink density of therubber may facilitate adhesive penetration of the rubberpolymer network. To investigate this phenomenon, each ofthe thermoset rubbers were cured to 80% of their ultimatemodulus (noted as T80 cure in the adhesive shear strengthtables), and tested for bond strength. These results werethen compared with those of the control for statisticallysignificant differences.

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CyanoacrylateAdhesivesGeneral DescriptionCyanoacrylates are one-part, room-temperature cur-ing adhesives that are available in viscosities rang-ing from water-thin liquids to thixotropic gels. Whenpressed into a thin film between two surfaces,cyanoacrylates cure rapidly to form rigid thermo-plastics with excellent adhesion to most substrates.

One of the benefits cyanoacrylates offer is the avail-ability of a wide variety of specialty formulationswith properties tailored to meet particularly chal-lenging applications. For example, rubber-tough-ened cyanoacrylates offer high peel strength andimpact resistance to complement the high shearand tensile strengths characteristic of cyanoacry-lates. Thermally resistant cyanoacrylates are avail-able which offer excellent bond strength retentionafter exposure to temperatures as high as 250°F forthousands of hours. Moreover, "surface-insensitive"cyanoacrylates offer rapid fixture times and curespeeds on acidic surfaces, such as wood or dichro-mated metals, which could slow the cure of acyanoacrylate. In some cases, the use of a general-purpose cyanoacrylate adhesive was hampered bythe appearance of a white haze around the bond-line. This phenomenon is known as "blooming" or"frosting" and occurs when cyanoacrylate monomervolatizes, reacts with moisture in the air, and settleson the part. To eliminate this problem, "low odor/lowbloom" cyanoacrylates were developed. They have alower vapor pressure than standard cyanoacrylatesand therefore are less likely to volatize. Whileadvances in cyanoacrylate formulating technologyhave played a key role in offering additional benefitsto the end user, there have also been importantdevelopments in cyanoacrylate primer and accelera-tor technology.

Accelerators speed the cure of cyanoacrylate adhe-sives and are primarily used to reduce cure and fix-ture times, to cure fillets on bondlines and/orexcess adhesive. Accelerators consist of an activeingredient dispersed in a solvent. The accelerator istypically applied to a substrate surface prior to theapplication of the adhesive. Once the carrier solventhas evaporated, the cyanoacrylate can immediatelybe applied and its cure initiated by the activespecies that the accelerator has left behind.Depending on the particular solvent and activespecies present in the accelerator, the solvent canrequire 10 to 60 seconds to evaporate, and the

active species can have an on-part life rangingfrom 1 minute to 72 hours. Accelerator can also besprayed over a drop of free cyanoacrylate to rapidlycure it. This technique has been widely used forwire tacking in the electronics industry.

Another benefit offered by cyanoacrylates is theavailability of primers which enable them to formstrong bonds with polyolefins and other hard-to-bond plastics such as fluoropolymers and acetalresins. Like the accelerators, polyolefin primers con-sist of an active ingredient dispersed in a solvent.Once the carrier solvent has evaporated, the surfaceis immediately ready for bonding, and the primerwill have an on-part life ranging from 4 minutes toone hour. Depending on the plastic, bond strengthsup to 20 times the unprimed bond strength can beachieved.

ChemistryCyanoacrylate adhesives are cyanoacrylate esters,of which methyl and ethyl cyanoacrylates are themost common. Cyanoacrylates undergo anionicpolymerization in the presence of a weak base, suchas water, and are stabilized through the addition ofa weak acid. When the adhesive contacts a surface,the water present on the surface neutralizes theacidic stabilizer in the adhesive, resulting in therapid polymerization of the cyanoacrylate.

Advantages• One-part system • Solvent free • Rapid room temperature cure • Excellent adhesion to many substrates • Easy to dispense in automated systems • Wide range of viscosities available • Excellent bond strength in shear and tensile mode • Primers available for polyolefins and difficult-to-

bond plastics

Disadvantages• Poor peel strength • Limited gap cure • Poor durability on glass• Limited resistance to polar solvents • Low temperature resistance • Bonds skin rapidly• May stress crack some plastics

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Light Curing AcrylicAdhesivesGeneral DescriptionLight curing acrylic adhesives are supplied as one-part, solvent-free liquids with viscosities rangingfrom 50 cP to thixotropic gels. Upon exposure tolight of the proper intensity and spectral output,these adhesives cure rapidly to form thermosetpolymers with excellent adhesion to a wide varietyof substrates. The cure times of light curing acrylicadhesives are dependent on many parameters,however, cure times of 2 to 60 seconds are typicaland cure depths in excess of 0.5" (13 mm) are pos-sible. Formulations of light curing acrylic adhesivesare available which vary in cured properties fromvery rigid, glassy materials to soft, flexible elas-tomers.

Light curing acrylic adhesives cure rapidly ondemand, which minimizes work in progress andoffers virtually unlimited repositioning time. In addi-tion, the wide range of viscosities available facili-tates the selection of a product for automated dis-pensing. These qualities make light curing acrylicsideally suited for automated bonding processes.

ChemistryLight curing acrylic adhesives are composed of ablend of monomers, oligomers, and polymers con-taining the acrylate functionality to which photoini-tiator is added. Upon exposure to light of the properintensity and spectral output, the photoinitiatordecomposes to yield free radicals. The free radicalsthen initiate polymerization of the adhesive throughthe acrylate groups to yield a thermoset polymer.

When the adhesive is cured in contact with air, thefree radicals created by the decomposition of thephotoinitiator can be scavenged by oxygen prior toinitiating polymerization. This can lead to incom-plete cure of the adhesive at the adhesive/oxygeninterface, yielding a tacky surface. To minimize thepossibility of forming a tacky surface, the irradianceof light reaching the adhesive can be increased, thespectral output of the light source can be matchedto the absorbance spectrum of the photoinitiator,and/or the adhesive can be covered with a nitrogenblanket during cure.

Advantages• Cure on demand • Very good environmental resistance • Wide range of viscosities available • Solvent free • Good gap filling • One part • Dispensing is easily automated • Clear bondlines • Rapid fixture and complete cure • Wide range of physical properties

Disadvantages• Light must be able to reach bondline • Oxygen can inhibit cure at the surface• Equipment expense for light source • If a high intensity light source is used, ozone must

be vented

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PolyurethaneAdhesivesGeneral DescriptionPolyurethane adhesives are supplied as one andtwo-part systems which range in viscosity from self-leveling liquids to non-slumping pastes. They cureto form thermoset polymers with good solvent andchemical resistance. They are extremely versatileand can range in cured form from extremely softelastomers to rigid, extremely hard plastics.Polyurethanes offer a good blend of cohesivestrength and flexibility which makes them verytough, durable adhesives. They bond well to mostunconditioned substrates, but may require the useof solvent-based primers to achieve high bondstrengths. They offer good toughness at low tem-peratures, but typically degrade in strength afterlong-term exposure above 302oF (150oC). Since thecure of one-part, moisture curing polyurethanes isdependent on moisture diffusing through the poly-mer, the maximum depth of cure that can beachieved in a reasonable time is limited at approxi-mately 0.375". Two-part systems, on the other hand,offer unlimited depth of cure.

ChemistryOne-part polyurethane adhesives react with mois-ture to polymerize. The moisture reacts with theisocyanate groups on the polymer, leading to theformation of chemical crosslinks between the poly-mer chains.

Advantages• Extremely tough• Good resistance to solvents• High cohesive strength• Good impact resistance

Disadvantages• Difficult to accelerate moisture cure• Limited depth of cure for one-part moisture cure

polyurethanes• Primer may be needed for adhesion to some

substrates• Limited high temperature use

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Two-Part No-MixAcrylic AdhesivesGeneral DescriptionTwo-part no-mix acrylic adhesives consist of a resinand an activator. The resin component is a solvent-free, high viscosity liquid, typically in the range of10,000 to 100,000 cP, while the activator componentis generally a solvent dispersion of the cure catalyst.

If the carrier solvent present in the activator solventdispersion is undesirable, the pure catalyst is alsoavailable as a solvent-free activator. However, whenusing a solvent-free activator, the amount of activa-tor applied must be tightly controlled, as excessiveactivator will detrimentally affect the performance ofthe adhesive.

The base resin of two-part no-mix acrylic adhesivescan also be heat cured. A typical heat cure cycle isten minutes at 300°F (149°C). Heat curing normallyoffers higher bond strengths and shorter cure times.However, heating the adhesive lowers the resin'sviscosity and may result in some adhesive flow outof large gaps. In some instances, it is desired to usea combination of these two cure methods, fixturingthe assembly with activator prior to heat cure.

Application MethodWhen an activator is used, the adhesive is cured inthe following manner:

• The resin is applied to one of the substrate surfaces

• The activator is applied to the other surface • The activator’s carrier solvent is allowed to flash

off • The two surfaces are mated together• The catalyst from the activator then initiates the

polymerization of the resin

Typically, these systems develop fixture strength intwo minutes and full strength in 4-24 hours. Theactivator serves only as a catalyst for the polymer-ization of the resin, so when using an activator, theratio of activator to resin is not critical. However, thisis not the case for solventless activators, becausethe activator is so concentrated that excess activator

can prevent the adhesive from forming an intimatebond with the substrate. Since polymerization is ini-tiated at the interface between the activator andresin, the cure depth is limited. Typically, the maxi-mum cure depth is 0.030" (0.76 mm) from this inter-face.

Chemistry The base resin consists of an elastomer dissolved inacrylic monomers. Peroxides are then blended in toprovide the resin with a source of free radicals. Theelastomer forms a rubbery phase which gives theadhesive its toughness, and the acrylic monomersform the thermoset polymer matrix which gives theadhesive its environmental resistance and strength.

The cure catalyst used in the activator is a coppersalt compounded with the products from the con-densation reaction of an amine and an aldehyde.This catalyst is often diluted in a solvent, although itis also supplied neat. Upon contact of the cure cat-alyst with the base resin, the peroxide in the baseresin decomposes to yield free radicals. These radi-cals then initiate polymerization through the acrylategroups on the monomer in the base resin.

Advantages• No mixing required • Good environmental resistance • High peel and impact strength • Bonds to lightly contaminated surfaces • Fast fixture and cure • Room temperature cure • Good adhesion to many substrates • Cure can be accelerated with heat

Disadvantages

• Difficult to automate dispensing • Messy • Activator may contain solvents • Unpleasant odor • Limited cure through depth • Yellow coloration of cured adhesive

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Silicone AdhesivesGeneral DescriptionSilicone adhesives are typically supplied as one-partsystems which range in viscosity from self-levelingliquids to non-slumping pastes. They cure to soft,thermoset elastomers with excellent property reten-tion over a wide temperature range. Silicones havegood adhesion to many substrates, but are limitedin their utility as structural adhesives by their lowcohesive strength.

Silicone adhesives are typically cured via reactionwith ambient humidity, although formulations arealso available which can be cured by exposure toultraviolet light of the proper irradiance and spectraloutput. Since the cure of moisture curing siliconesis dependent on moisture diffusing through the sili-cone matrix, the cure rate is strongly affected by theambient relative humidity. Moisture curing siliconeshave a maximum depth of cure which is limited to0.375 - 0.500". At 50% RH, moisture cure siliconeswill cure to a tack free surface in 5-60 minutesdepending on the type used. Complete curethrough thick sections of silicone can take up to 72hours. It should be noted that adhesive strengthmay continue to develop for 1-2 weeks after the sili-cone has been applied. This occurs because thereaction between the reactive groups on the siliconepolymer and the reactive groups on the substratesurface is slower than the crosslinking reaction ofthe silicone groups with themselves.

Moisture curing silicones are categorized by the by-product given off as they cure with moisture. Forexample, acetoxy cure silicones give off acetic acid.Alkoxy cure silicones give off alcohols, typicallymethanol or ethanol, and oxime curing siliconesevolve oxime. Acetoxy cure silicones are known fortheir ability to cure rapidly and develop good adhe-sion to many substrates. Their largest limitation isthe potential for the byproduct acetic acid to pro-mote corrosion. Alkoxy cure silicones, on the otherhand, do not have this limitation because the alco-hol byproducts are non-corrosive. This makes themwell suited for electronic and medical applicationswhere the acetic acid could be a problem.Unfortunately, alkoxy silicones typically have loweradhesion and take longer to cure than acetoxy sili-cones. Oxime evolving silicones offer cure speedsand adhesion which rivals, and in some cases sur-passes, that of acetoxy cure silicones. However, theoxime they evolve will not corrode ferric substrates,although it can stain copper or brass.

Consequently, oxime silicones have found wide-spread use in automotive gasketing applications. The chief limitation of all moisture curing siliconesis the difficulty associated with accelerating the curerate. This concern was addressed through thedevelopment of UV cure silicones.

Ultraviolet light curing silicones generally also havea secondary moisture cure mechanism to insurethat any silicone which is not irradiated with ultravi-olet light will still cure. Upon exposure to ultravioletlight of the proper irradiance and intensity, they willform a tack free surface and cure to a polymer withup to 80% of its ultimate physical strength in lessthan a minute. Initial adhesion can be good, butbecause ultimate bond strength is dependent on themoisture cure portion of the silicone, full bondstrength can take 1-2 weeks to develop. The adhe-sive strength achieved by a UV/moisture cure sili-cone is typically a function of the type of moisturecure used. Silicones with a secondary acetoxy cureshow good bond strength while those with a sec-ondary alkoxy cure are lower.

ChemistrySilicone formulations are available which can becured through moisture, heat, mixing two compo-nents and exposure to ultraviolet light. The sili-cones used for adhesives are typically the one-partmoisture curing and UV curing silicones. All sili-cones have a chemical backbone made up of sili-cone to oxygen bonds, known as siloxane bonds. Itis the high energy of this bond that gives siliconestheir unique high temperature performance proper-ties.

Advantages• One-part systems available• Solvent free • Room temperature cure • Excellent adhesion to many substrates • Extremely flexible• UV Curing formulations available

Disadvantages• Poor cohesive strength• Moisture cure systems have limited depth of cure• Swelled by non-polar solvents

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Why BondElastomers WithLoctite Adhesives?Advantages Over OtherAssembly MethodsAdhesives offer an array of benefits to the manu-facturer who needs to join elastomeric substrates toother substrates in their manufacturing process.These benefits are best understood by comparingadhesive joining processes with the other options amanufacturing engineer can consider.

Advantages Versus MechanicalFastenersMechanical fasteners are quick and easy to use, buthave a number of significant drawbacks.

• They create stresses in the elastomer, which may lead to distortion or ripping of the part; adhesives do not.

• There are extra components which must be purchased and inventoried. Adhesives require no extra components.

• They require altering the design of the product to include bosses and holes. Adhesives require no special features.

• Their appearance often interferes with the styling of the product. Adhesives are invisible inside a bonded joint.

• They concentrate all of the holding power at the fastener location, causing the applied load to be carried by a small area of elastomer. Adhesives spread the load evenly over the entire joint area.

Advantages Versus Ultrasonic WeldingUltrasonic welding can be an excellent method forcertain types of assemblies. There are, however, anumber of factors which limit its usefulness.

• The dampening characteristics of most elas-tomers can make them poor candidates for ultrasonic welding. Adhesives are not limited in this fashion.

• Ultrasonic welding is not usable for thermoset rubbers. Adhesives are.

• Joining of elastomers to metal, glass, or other materials is not feasible in most cases. Adhesives do this easily.

• The design of joints is restricted to geometries which are favorable to the process. Ideally, they should have asmall, uniform contact area to concentrate the ultrasonicenergy. Adhesives can accommodate irregular bond lines.

• The capability of joining different thermoplastic elas-tomers in the same assembly is limited to those which are chemically compatible and have similar melting points. Adhesives are not restricted in this way.

• Ultrasonic welding requires investment in machinery as well as special tooling for each part. Adhesives require no machinery or tooling.

Advantages Versus Solvent WeldingSolvent welding can be a useful, low-cost method of bondingelastomers. However, its usefulness is limited by a numberof disadvantages.

• Solvent welding cannot be used with dissimilar materialssuch as metals or glass. Adhesives do the job.

• Solvents will not work with thermoset rubbers. Adhesives will.

• Solvents are more likely to cause stress cracking than are adhesives.

• The time between application of the solvent and joining the parts is critical. The joints are weak if too much sol-vent remains in the bond area or if too much solvent hasflashed off prior to assembly. Adhesives have a much less critical open time.

• Solvent cementing is not capable of joining parts with significant gaps between them. Adhesives tolerate much larger gaps.

Advantages Over Other AdhesivesLoctite cyanoacrylate, acrylic, polyurethane and siliconeadhesives are the first choice for speed, ease of use, andoverall convenience. They are adhesives that easily adaptthemselves to high-speed production lines without heat cur-ing ovens or mixing equipment. When total costs of the fin-ished product are considered, they are often the most eco-nomical.

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Advantages Versus EpoxiesEpoxies, when first introduced, were a major break-through in adhesive technology. Their ability tocure at room temperature without excessive shrink-age, combined with versatility of formulation, madethem extremely useful materials. However, they arenot the easiest materials to use for the followingreasons:

• They usually must be mixed immediately prior to use, requiring extensive hand labor or sophisticated mixing equipment.

• The time from mixing to use is often critical to success, but is difficult to control, particularly when the production rate is irregular.

• Limits to pot life often cause waste of material.• Epoxies requiring heat cures have limited use-

fulness on heat sensitive elastomers.• Cure times without heat are too long for auto-

mated assembly.

The Loctite Design Guide for Bonding Rubbers and TPEs 8

Advantages Versus Hot MeltsHot melts are low cost, single component, fast-set-ting adhesives. As such, they often find use bond-ing packaging components, furniture or toys. Theirlimitations, however, are significant.

• Hot melts have poor temperature resistance.• They require special equipment to melt and

dispense the adhesive.• They are messy.• Control of the joint open time is critical to per-

formance.• Material held in the melted form for extended

periods of time may degrade.

Advantages Versus Solvent CementsSolvent cements are low cost materials which havebeen traditionally used to join plastics. Their prima-ry advantage is low cost, yet their limitations arenumerous.

• They have poor resistance to heat and solvents.• They produce solvent fumes which may be

toxic or flammable.• The open time of the bonded joint is critical.• They require an extensive drying time.• Solvent trapped inside the joint may lead to

porosity or weakness.


How To Use The Bonding Chapters


Thermoplastic Vulcanizates (TPV)

thermoplastic elastomer

Trade Names Manufacturer• Geolast Advanced Elastomer Systems• Santoprene Advanced Elastomer Systems

General DescriptionThermoplastic vulcanizates are elastomeric alloys of acontinuous plastic phase and a fine dispersion ofdynamically vulcanized rubber. Santoprene, for exam-ple, uses polypropylene as the plastic phase withEPDM as the rubber phase. Geolast also usespolypropylene for the plastic phase, however, nitrilerubber is used for the thermoset rubber phase.Generally, these compounds derive their physical prop-erties from the interaction of the two phases and donot use the fillers and extenders commonly used withmost thermoset rubber systems. Consequently, materi-al properties are primarily a function of the type andlevel of vulcanizate and its degree of crosslinking.Even though TPVs contain a vulcanizate phase, thesematerials can still be processed by common thermo-plastic processing equipment such as extrusion, injec-tion molding, blow molding, thermoforming and calen-dering.

General PropertiesIn general, TPVs offer the performance properties of athermoset rubber with the processing ease of a ther-moplastic. These properties include good tensilestrength, good abrasion resistance and outstandingfatigue flex resistance. The saturated nature of theolefinic backbone in the Santoprene and Geolast plas-tic phases, coupled with the highly crosslinked natureof their vulcanizate phases, gives them excellent chem-ical resistance, as well as good thermal and weather-ing resistance. Santoprene has shown good propertyretention after long-term exposure to acids, bases, andaqueous solutions. Resistance to oils and other hydro-carbons varies with grade and fluid type. However, thehigher the polarity of the fluid the more likely it is toattack Santoprene. For increased oil resistance,Geolast offers superior performance because it utilizesnitrile as the vulcanizate phase rather than EPDM.Unlike most TPEs, which soften at high temperatures,TPVs have shown good property retention at tempera-tures as high as 275oF (135oC) and good compressionset resistance at temperatures as high as 212oF(100oC). Their low temperature performance is alsogood with brittle points below -67oF (-55oC).

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Typical Applications• Automotive Air ducts, rack and pinion steering

boots, motor drive belts

• Construction Glazing seals, expansion joints

• Electrical Specialty wire and cable insulation

• Medical Drug vial stoppers, grommets, syringe plunger tips, volumetric infusion pump tips

• Miscellaneous Sander grips, squeegees, dust seals, clothes washer filter seals

Relative Adhesive Performance• High Prism Primer - Prism 401/Prism 770

• Medium Surface Insensitive CA - Prism 401Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105

• Low Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives Grey Concentrate - Increase

Surface Treatments• Prism Primer Increase

Typical ApplicationsLists common markets where theelastomer is used and specificapplications.

Trade NamesLists common suppliers of eachelastomer and the trade namesof their products.

General DescriptionProvides information concerningthe chemical structure, typesavailable and cure method used(if appropriate).

General PropertiesDescribes the key characteristicsof each elastomer.

Surface TreatmentsSummarizes the effect ofPrism Primer on cyanoacrylateadhesive performance.

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Effects of Formulation and ProcessingHighlights formulation or elastomer processingchanges which had a significant effect on adhe-sive performance.

Relative AdhesivePerformanceProvides relative ranking ofbond strengths achieved withadhesives tested.

Elastomer DescriptionThe elastomer formulations were selected intwo ways. For five of the twenty-five elas-tomers evaluated, commercially availablegrades were evaluated which were selectedto represent each of the major categories ofthat elastomer. The twenty remaining elas-tomers were specifically compounded forthe purpose of determining the effect ofindividual additives and fillers on the bond-ability of that material.

• Commercially Available GradesIf commercially available grades were evaluated, then the specific grades whichwere tested were listed in the left-hand column of this table.

• Specialty FormulationsIf special formulations were com-pounded, then the additive, filler, processing change or change in chemical structure was indicated, as well as the specific concentration and product used, in the left-hand col-umn of this table.

The Loctite Design Guide for Bonding Rubbers and TPEsThe Loctite Design Guide for Bonding Rubbers and TPEs 11

How To Use The Adhesive Shear Strength Table

PS Blend Kraton D 1101 100 phr 530 510 630 450 520 90 250 290 1020 480Polystyrene 100 phr 3.65 3.52 4.34 3.10 3.59 0.62 1.72 2.00 7.03 3.31

Cure System Usedin All FormulationsNone Required

Control: Kraton G 1650 100 phr 290 >510D 370 230 230 90 170 170 660 180S-EB-S 2.00 >3.52D 2.55 1.59 1.59 0.62 1.17 1.17 4.55 1.24

The Loctite Design G

uide for Bonding R

ubber and TPEs

59

Carbon Black Kraton G 1650 100 phr 530 >810D 570 360 620 50 170 280 660 270N-550 100 phr 3.65 >5.59D 3.93 2.48 4.27 0.34 1.17 1.93 4.55 1.86

Clay Kraton G 1650 100 phr 220 510 580 320 340 50 170 230 >1090D 220Dixie Clay 100 phr 1.52 3.52 4.00 2.21 2.34 0.34 1.17 1.59 >7.52D 1.52

Silica Kraton G 1650 100 phr 440 >550D >550D 390 510 30 60 390 >660D 350Hi Sil 233 50 phr 3.03 >3.52D >3.79D 2.69 3.52 0.21 0.41 2.69 >4.55D 2.41

Whiting Kraton G 1650 100 phr 50 180 >200D 40 40 30 30 30 180 70Precipitated Whiting 100 phr 0.34 1.24 >1.35D 0.28 0.28 0.21 0.21 0.21 1.24 0.48

Aromatic Oil Kraton G 1650 100 phr 140 >300D 150 150 140 20 50 40 160 80Aromatic Oil 100 phr 0.97 >2.07D 1.03 1.03 0.97 0.14 0.34 0.28 1.10 0.55

Naphthenic Oil Kraton G 1650 100 phr 80 300 >370D 90 80 <10 50 40 170 60Naphthenic Oil 100 phr 0.55 2.07 >2.55D 0.62 0.55 <0.07 0.34 0.28 1.17 0.41

Plasticizer Kraton G 1650 100 phr 10 <10 20 10 20 <10 <10 <10 20 10Dioctyl Phthalate 50 phr 0.07 <0.07 0.14 0.07 0.14 <0.07 <0.07 <0.07 0.14 0.07

Processing Aid Kraton G 1650 100 phr 290 510 370 390 230 90 110 210 410 180Carnauba Wax 10 phr 2.00 3.52 2.55 2.69 1.59 0.622 0.76 1.45 2.83 1.24

EVA Blend Kraton G 1650 100 phr 130 240 370 180 140 20 40 170 410 220EVA 20 phr 0.90 1.65 2.55 1.24 0.97 0.14 0.28 1.17 2.83 1.52

PE Blend Kraton G 1650 100 phr 520 510 550 370 550 60 80 350 660 310Polyethylene 100 phr 3.59 3.52 3.79 2.55 3.79 0.41 0.55 2.41 4.55 2.14

Antistatic Kraton G 1650 100 phr 220 190 160 230 230 <10 100 120 260 50Armostat 550 5 phr 1.52 1.31 1.10 1.59 1.59 <0.07 0.69 0.83 1.79 0.34

Kraton D 1101 100 phr 160 280 370 230 230 50 170 130 >430D 180S-B-S Linear 1.10 1.93 2.55 1.59 1.59 0.34 1.17 0.90 >2.96D 1.24

C-Flex 100 phr 140 >240D 220 80 100 10 20 30 170 40Silicone Oil 0.97 >1.65D 1.52 0.55 0.69 0.07 0.14 0.21 1.17 0.28

Kraton D 1118X 100 phr 120 130 150 120 140 70 170 90 320 130SB Type Branched 0.83 0.90 1.03 0.83 0.97 0.48 1.17 0.62 2.21 0.90

ADHESIVE SHEAR STRENGTH(psi)

(MPa)

Styrene Butadiene TPE Kraton by Shell Chemical and C-Flex by Concept Polymer Technology

Loctite Adhesive496 PRISM 401 PRISM 401/ PRISM 480 PRISM 4204 Superflex Ultra Black Depend 330 3105 3951

Methyl Surface PRISM Rubber Rubber 595 5900 2-part Light Cure PolyurethaneCyanoacrylate Insensitive Primer 770 Toughened Toughened Acetoxy RTV Oxime RTV No-Mix Acrylic w/7251

Cyanoacrylate Polyolefin Primer Cyanoacrylate Cyanoacrylate Silicone Silicone Acrylic Primer

NOTES: = The addition of the indicated additive (or processing change) caused a statistically significant increase in the bond strength within 95% confidence limits.

= The addition of the indicated additive (or processing change) caused a statistically significant decrease in the bond strength within 95% confidence limits.

D = The force applied to the test specimens exceeded the strength of the material resulting in substrate failure before the actual bond strength achieved by the adhesive could be determined.

Single LineA single line in the table indicates thatthe elastomer evaluated below the linewas formulated from a control andcompared back to that control to deter-mine the effect of an additive, filler,processing change or change in chem-istry. To determine the control, move upthe table from the single line until arow has a double line on top of thetable. That row will be the control andis often denoted as the “control”.

10

ShadingWhen the cell is shaded grey, the addi-tion of the indicated additive or filler,the processing change or the change inthe chemical make-up of the polymerresulted in a statistically significantincrease in bondability when comparedto the control. A statistically significantdecrease is denoted by red shading. Ifthere is a change in the failure mode,the cell is also shaded accordingly.

NotesThis section explains the superscriptsand shading used in the table.

Double LineA double line in the table indicates that the elastomerevaluated below the line was not compared to a con-trol to determine the effect of a filler, additive, pro-cessing change or change in the polymer chemistry.

T80 Cure (not shown)Stopping the polymerization processbefore completion could theoreticallyincrease its bondability for two reasons.The first reason being that the lowercrosslink density of the polymer allowsfor increased diffusion of the adhesiveinto the rubber. The second reasonbeing that the active species that werenot utilized during vulcanization cannow react with the adhesive. In thistesting, the polymerization was stoppedwhen the modulus was 80% of themodulus at full cure.

ControlThe control is an unfilled elastomer that wasused as the base resin for all compoundedformulations. It is listed at the top of thetable and is indicated as the “control”. Eachformulation of elastomer was produced bycompounding the unfilled elastomer with asingle additive or filler. That formulation wasthen compared to the control to determinestatistically significant effects within 95%confidence limits. In some cases, a changein the process or the chemical compositionwas evaluated. In these cases, that specificformulation may not have been compound-ed using the control elastomers but wascompared to the control to determine theeffect of the change.


Butyl Rubber (IIR)

thermoset rubber

Trade Names Manufacturer• Exxon Butyl Exxon Chemical • Polysar Butyl Bayer

General DescriptionButyl rubber is poly(methylpropene-co-2-methyl-1,3butadiene) or poly(isobutylene-co-isoprene). The rub-ber gum stock is produced through the cationic poly-merization of isobutylene with 1-3% isoprene. The iso-prene is incorporated into the polymer structure to pro-vide unsaturated sites which can be utilized to formcured rubber from the gum stock. Butyl rubber is typi-cally crosslinked using sulfur, however, two othermethods are also available. The first method is to reactthe butyl gum stock with phenol-formaldehyde resin.The other involves reacting it with p-quinone dioxime,or p-quinone dioxime dibenzoate, in conjunction withlead oxide. The crosslink density and ultimate proper-ties of the cured rubber can be controlled by varyingthe amount of unsaturation in the base polymer. Theproperties of the base polymer are also controlled byvarying the molecular weight of the polymer and thedegree of branching in the gum stock. Halogenationof these rubbers has been used to produce the familyof halogenated butyl rubbers which are discussed in aseparate chapter.

General PropertiesThe saturation of the polymer backbone and lack ofreactive groups result in a combination of valuableproperties that have made butyl polymers one of themost widely used synthetic elastomers. The aliphaticnature of the polymer gives it good resistance toozone, UV light, moisture and mineral acids. This alsocontributes to its thermal resistance, which is limitedmore by the type of crosslink system used than thestability of the polymer backbone. Butyl rubber formu-lations cured using sulfur tend to degrade after long-term exposure to temperatures above 302o F (150oC).Formulations which utilize the phenol formaldehyderesin cure system offer much better thermal resistance.Butyl rubber is attacked by non-polar solvents, such ashydrocarbon oils, greases and fuels. Alternatively,butyl rubbers have good resistance to polar liquidssuch as oxygenated solvents, ester type plasticizers,vegetable oils and synthetic hydraulic fluids. The lackof bulky pendant groups on the polymer chains allowsthem to pack closely and give a vulcanizate withextremely low gas permeability. This has resulted inthe widespread use of butyl rubber in inner tubes and

12

other industrial gas bladders. Butyl compounds havegood damping and shock absorption characteristicswhich has led to their use in automotive body mounts.

Typical Applications• Automotive Tire innerliners, inner tubes,

radiator hose, belts

• Electronics Electrical insulation

• Industrial Conveyor belts, curing bladders, membranes, freezer gaskets, tank linings, steam hose, diaphragms

• Miscellaneous Dock fenders

Relative Adhesive Performance• High Methyl CA - Superbonder 496

Surface Insensitive CA - Prism 401Prism Primer - Prism 401/Prism 770

• Medium Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Light Curing Acrylic - Loctite 3105

• Low Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives Carbon Black - Increase

Clay - IncreaseSilica - IncreaseParaffinic Oil - DecreaseProcessing Aid - DecreaseAntistat - Increase CA

• T80 Cure No Trend Apparent




∆ = The force applied to the test specimens exceeded the strength of the material resulting in substrate failure before the actual bond strength achieved by the adhesive could be determined.

Butyl Rubber Butyl Rubber by Exxon Chemical





(MPa)

Cure System Usedin All FormulationsStearic Acid 1.00 phrZinc Oxide 5.00 phrSulfur 2.00 phrMBT 0.50 phrTMTD 1.00 phr


uide for Bonding R

ubbers and TPEs

13

T80 Cure Butyl 165 100 phr >110∆ >130∆ >140∆ 80 110 30 60 60 60 30Cured to 80% of Modulus at Full Cure >0.76∆ >0.90∆ >0.97∆ 0.55 0.76 0.21 0.41 0.41 0.41 0.21Low Unsaturation Butyl 065 100 phr >110∆ >140∆ >140∆ 100 110 20 40 80 80 40

0.8% Unsaturation >0.76∆ >0.97∆ >0.97∆ 0.69 0.76 0.14 0.28 0.55 0.55 0.28

High Unsaturation Butyl 268 100 phr >100∆ >110∆ >140∆ >100∆ >100∆ 30 60 60 90 301.6% Unsaturation >0.69∆ >0.76∆ >0.97∆ >0.69∆ >0.69∆ 0.21 0.41 0.41 0.62 0.21

Carbon Black Butyl 165 100 phr 430 >490∆ >640∆ 170 340 80 130 170 300 100N-550 40 phr 2.97 >3.38∆ >4.41∆ 1.17 2.34 0.55 0.90 1.17 2.07 0.69

Clay Butyl 165 100 phr >210∆ >270∆ >230∆ 150 150 60 100 140 160 100Dixie Clay 100 phr >1.45∆ >1.86∆ >1.59∆ 1.03 1.03 0.41 0.69 0.97 1.10 0.69

Silica Butyl 165 100 phr >210∆ >330∆ >360∆ 160 200 50 70 90 120 50Hi Sil 233 20 phr >1.45∆ >2.28∆ >2.48∆ 1.10 1.38 0.34 0.48 0.62 0.83 0.34

Paraffinic Oil Butyl 165 100 phr >80∆ >110∆ >100∆ 60 70 20 30 30 60 30Paraffinic Oil 20 phr >0.55∆ >0.76∆ >0.69∆ 0.41 0.48 0.14 0.21 0.21 0.41 0.21

Processing Aid Butyl 165 100 phr 80 >110∆ >140∆ 70 80 30 20 60 60 20Petrolatum 4 phr 0.55 >0.76∆ >0.97∆ 0.48 0.55 0.21 0.14 0.41 0.41 0.14

Antiozonant Butyl 165 100 phr >120∆ >110∆ >140∆ >140∆ >110∆ 20 40 60 90 30Vanox NBC 3.5 phr >0.83∆ >0.76∆ >0.97∆ >0.97∆ >0.76∆ 0.14 0.28 0.41 0.62 0.21

Antistatic Butyl 165 100 phr >120∆ >140∆ >140∆ >130∆ >160∆ 40 40 60 70 30Armostat 550 5 phr >0.83∆ >0.97∆ >0.97∆ >0.90∆ >1.10∆ 0.28 0.28 0.41 0.48 0.21

Control: Butyl 165 100 phr >90∆ >110∆ >140∆ 100 >110∆ <10 60 60 90 401.2% Unsaturation >0.62∆ >0.76∆ >0.97∆ 0.69 >0.76∆ <10 0.41 0.41 0.62 0.28


Chlorosulfonated Polyethylene (CSM)

thermoset rubber

Trade Names Manufacturer• Hypalon DuPont Dow Elastomers

General DescriptionChlorosulfonated polyethylene (CSM) is produced viathe simultaneous chlorination and chlorosulfonation ofpolyethylene in an inert solvent. The addition of thechlorine groups increases the molecular irregularity ofthe CSM which contributes to its flexibility. The pen-dant chlorine groups also increase chemical resistanceand flame retardance, while the sulfonyl groups pro-vide crosslinking sites. The sulfur content of CSM isnormally maintained at approximately 1%, while thechlorine content varies over a wide range. Low chlo-rine content formulations retain some of the stiffermechanical properties of PE due to their partial crys-tallinity. Increasing the chlorine content improves oilresistance and flame resistance.

General PropertiesThe most notable properties of CSM are its chemicalresistance (especially to oxygen, oil and ozone), tensileproperties and low temperature properties. Thechemical resistance of CSM is much better than thatof neoprene and nitrile rubbers. The extremely polarnature of the polymer’s backbone makes it especiallywell suited for non-polar service environments. Theozone resistance of CSM is such that antiozonants arenot normally used. CSM is tougher than silicone andEPDM. This is illustrated by the high tensile strengthsthat are achieved by CSM without high filler levels.The properties of CSM are very dependent on thechlorine content. As the chlorine content increases,the heat resistance, low temperature flexibility andelectrical resistance decrease. The ozone resistancealso decreases, but the effect is much lower in magni-tude than that of the aforementioned properties. Onthe other hand, as the chlorine content increases, theflame resistance and oil resistance increase. The elec-trical properties of CSM are better than most elas-tomers, but not as good as EPDM. Compounds ofCSM can be formulated with excellent abrasion resis-tance and brittle temperatures as low as -76oF (-60oC). Other noteworthy properties of CSM are itsexcellent radiation resistance and color stability.

14

Typical Applications• Automotive Hoses, spark plug boots

• Industrial Hoses, coatings

• Consumer Pond liners, roof membranes

Relative Adhesive Performance• High Methyl CA - Super Bonder 496




Effects of Formulation and Processing• Additives Low Chlorine - Increase

High Chlorine - IncreaseCarbon Black - IncreaseCalcium Carbonate - IncreaseClay - IncreaseSilica - IncreaseTitanium Dioxide - IncreaseAntistatic - Increase





∆ = The force applied to the test specimens exceeded the strength of the material resulting in substrate failure before the actual bond strength achieved by theadhesive could be determined.

Chlorosulfonated Polyethylene Hypalon by DuPont Dow Elastomers





(MPa)

Cure System Usedin All FormulationsMagnesium Oxide 4.00 phrTMTD 2.00 phrRubber Maker’s Sulfur 1.00 phr

Control: Hypalon 40 100 phr >510∆ >610∆ >550∆ 190 270 60 120 160 250 10035% Chlorine >3.52∆ >4.21∆ >3.79∆ 1.31 1.86 0.41 0.83 1.10 1.72 0.69


uide for Bonding R

ubbers and TPEs

15

T80 Cure Hypalon 40 100 phr >510∆ >610∆ >550∆ 190 270 50 120 110 180 100Cured to 80% of Modulus at Full Cure >3.52∆ >4.21∆ >3.79∆ 1.31 1.86 0.34 0.83 0.76 1.24 0.69Low Chlorine Hypalon 45 100 phr >660∆ >870∆ >550∆ 410 >520∆ 90 240 360 400 230

24% Chlorine >4.55∆ >6.00∆ >3.79∆ 2.83 >3.59∆ 0.62 1.66 2.48 2.76 1.59

High Chlorine Hypalon 48 100 phr >510∆ >610∆ 700 260 270 80 150 240 480 17043% Chlorine >3.52∆ >4.21∆ 4.83 1.79 1.86 0.55 1.03 1.66 3.31 1.17

Carbon Black Hypalon 40 100 phr >850∆ >1010∆ >870∆ 540 840 100 240 830 1030 410N-990 100 phr >5.86∆ >6.97∆ >6.00∆ 3.72 5.79 0.69 1.66 5.72 7.10 2.83

Calcium Carbonate Hypalon 40 100 phr >400∆ >450∆ >410∆ 390 >390∆ 120 210 330 >700∆ 240Calcium Carbonate 100 phr >2.76∆ >3.10∆ >2.83∆ 2.69 >2.69∆ 0.83 1.45 2.28 >4.83∆ 1.66

Clay Hypalon 40 100 phr >510∆ >610∆ >550∆ 190 390 100 120 200 930 180Dixie Clay 50 phr >3.52∆ >4.21∆ >3.79∆ 1.31 2.69 0.69 0.83 1.38 6.41 1.24

Silica Hypalon 40 100 phr >540∆ >1000∆ >550∆ 510 720 60 210 540 860 280Hi Sil 233 50 phr >3.72∆ >6.90∆ >3.79∆ 3.52 4.97 0.41 1.45 3.72 5.93 1.93

Titanium Dioxide Hypalon 40 100 phr >510∆ >800∆ >750∆ 260 270 60 150 230 1050 160Titanium Dioxide 40 phr >3.52∆ >5.52∆ >5.17∆ 1.79 1.86 0.41 1.03 1.59 7.24 1.10

Aromatic Oil Hypalon 40 100 phr 160 >610∆ >550∆ >190∆ >270∆ <10 50 80 90 40Sundex 790 75 phr 1.10 >4.21∆ >3.79∆ >1.31∆ >1.86∆ <0.07 0.34 0.55 0.62 0.28

Napthenic Oil Hypalon 40 100 phr >990∆ >940∆ >960∆ 190 270 40 120 160 250 100Calsol 8240 30 phr >6.83∆ >6.48∆ >6.62∆ 1.31 1.86 0.28 0.83 1.10 1.72 0.69

Polyethylene Wax Hypalon 40 100 phr >510∆ >410∆ >550∆ 120 270 120 50 200 250 100AC617A 10 phr >3.52∆ >2.83∆ >3.79∆ 0.83 1.86 0.83 0.34 1.38 1.72 0.69

Antistatic Hypalon 40 100 phr >510∆ >610∆ >550∆ 430 >360∆ 60 140 250 550 140Armostat 550 5 phr >3.52∆ >4.21∆ >3.79∆ 2.97 >2.48∆ 0.41 0.97 1.72 3.79 0.97


Copolyester TPE


Trade Names Manufacturer• Ecdel Eastman• Hytrel DuPont• Lomod GE• Riteflex Hoescht Celanese

General DescriptionCopolyester TPE is composed of alternating hard poly-1,4-butanediol terephthalate and soft long-chainpolyalkylene ether terephthalate block copolymers con-nected by ester and ether linkages. Copolyester hasan -A-B-A-B- structure. However, the performance ofcopolyester TPE is analogous to that of three blockcopolymers such as styrenic TPEs.

General PropertiesThe cost of copolyester TPE is above average, but theperformance is also above average. They have 2 to 15times the strength of conventional rubbers. Thismeans that replacing a thermoset rubber with acopolyester TPE can result in a significant decrease inthe part volume and weight. Consequently, the optionof reducing the required size of the part while achiev-ing the original mechanical and strength propertiescan significantly offset the higher cost of copolyesterTPE. Copolyester TPE has very good resistance toorganic solvents and aqueous solutions. However, theyhave poor resistance to halogenated solvents, acidsand bases. They have moderate thermal resistancewith recommended service temperatures ranging from-67 to 285oF (-55 to 140oC). Below their elastic limit,copolyester TPE has excellent physical properties.Tensile strength ranges from 3000 to 8000 psi (20.7 to55.2 MPa). The elastic limit of copolyester TPE is only25%, which is low for an elastomer. Above this elon-gation, the polymer will be permanently deformed. Thelow elongation is accompanied by an unusually highhardness. The hardness typically ranges from 40 to 75Shore D. Plasticizer is not used when compoundingcopolyester TPEs. This makes copolyester TPE purerthan most other TPEs which, consequently, makesthem especially well suited for medical and food appli-cations.

16

Typical Applications• Automotive Fuel tanks, gear wheels, boots,

drive belts

• Consumer Ski boots

• Industrial Gears, belts, bellows, boots, coiltubing and cables

Relative Adhesive Performance• High Surface Insensitive CA - Prism 401

Prism Primer - Prism 401/Prism 770Light Curing Acrylic - Loctite 3105

• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951

• Low Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900

Surface Treatments• Prism Primer Decrease




Copolyester TPE Hytrel by DuPont





(MPa)

Cure System Usedin All Formulations

None Required

Hytrel G5544 100 phr 330 1570 1510 510 560 20 170 350 1220 9102.28 10.83 10.41 3.52 3.86 0.14 1.17 2.41 8.41 6.72


uide for Bonding R

ubbers and TPEs

17

Hytrel 7246 100 phr 1180 1020 650 400 470 120 120 470 1170 6508.14 7.03 4.48 2.76 3.24 0.83 0.83 3.24 8.07 4.48


Epichlorohydrin Rubber (CO, ECO, GCO, GECO)

thermoset rubber

Trade Names Manufacturer• Hydrin Zeon

General DescriptionEpichlorohydrin polymers are available as a homopoly-mer (CO) of epichlorohydrin, epichlorohydrin/ethyleneoxide copolymer (ECO), epichlorohydrin/allyl glycidylether copolymer (GCO) and epichlorohydrin/ethyleneoxide/allyl glycidyl ether terpolymer (GECO). The ethyl-ene oxide content varies from zero in the homopoly-mer, to 32 to 35% for terpolymers and up to 50% forcopolymers. As ethylene oxide content increases, thehalogen content and polarity of the polymer decreases.Blends of the various rubber types are used to obtainspecific properties. The allyl glycidyl ether provides acure site on the polymer backbone. This permits theuse of other cure systems, such as peroxides, ratherthan the sulfur-based systems which are typically usedfor CO and ECO.

General PropertiesAll epichlorohydrin polymers offer low temperatureflexibility; resistance to oils, fuel and common solvents;low gas permeability; good weatherability and gooddynamic properties. The specific degree to whichthese properties are manifested vary with each type ofepichlorohydrin polymer. Because all epichlorohydrinpolymers have a completely saturated backbone, theyall have good resistance to UV, ozone and thermaldegradation. For the lowest gas permeability, thehomopolymer is the polymer of choice . The lowerhalogen content in the copolymers and terpolymerimparts a higher degree of flexibility to the backboneand results in improved low temperature performanceof the material. This improvement is gained at theexpense of an increase in permeability. If the ECOcopolymer is difficult to cure, or the properties thatresult from the sulfur-based cure systems are unac-ceptable, copolymer or terpolymer containing the allylglycidyl ether monomer can be used. The unsaturatedsite opens the door to cure by a peroxide system. Thisyields improved high temperature properties and com-pression set resistance over sulfur cured systems. Thecopolymers and terpolymer have a lower halogen con-tent than the pure homopolymer. Consequently, theresistance to non-polar solvents, such as fuels and oils,is decreased. Aqueous and non-aqueous electrolytesrapidly degrade the polar epichlorohydrin polymer.

18

Typical Applications• Automotive Fuel pump diaphragms, hoses,

motor mounts, boots, seals, o-rings, air conditioning system components

• Industrial Gaskets, rolls, belts, bladders,

• Medical Oxygen mask hoses


Surface Insensitive CA - Prism 401Prism Primer - Prism 401/Prism 770Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204

• Medium Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Hydrin C - Increase CA

Hydrin T - Increase CACarbon Black - IncreasePlasticizer - Decrease

• T80 Cure Increase CA

Surface Treatments• Prism Primer No Trend Apparent

Epichlorohydrin Rubber Hydrin by Zeon Chemical Corporation








(MPa)

Cure System Usedin All FormulationsZinc Oxide 3.00 phrZO-9 2.00 phrEthylene Thiurea 2.00 phr

Control: Hydrin H 100 phr >120∆ >110∆ >140∆ >100∆ >120∆ 60 60 100 >160∆ 110Homopolymer >0.83∆ >0.76∆ >0.97∆ >0.69∆ >0.83∆ 0.41 0.41 0.69 >1.10∆ 0.76


uide for Bonding R

ubbers and TPEs

19

T80 Cure Hydrin H 100 phr >150∆ >160∆ >140∆ >130∆ >120∆ 40 60 100 >200∆ 110Cured to 80% of Modulus at Full Cure >1.03∆ >1.10∆ >0.97∆ >0.90∆ >0.83∆ 0.28 0.41 0.69 >1.38∆ 0.76Hydrin C Hydrin C 100 phr >310∆ >150∆ >160∆ >120∆ >120∆ 60 60 80 160 80ECO copolymer >2.14∆ >1.03∆ >1.10∆ >0.83∆ >0.83∆ 0.41 0.41 0.55 1.10 0.55

Hydrin T Hydrin T 100 phr >140∆ >150∆ >140∆ >100∆ >110∆ 40 70 >60∆ >160∆ 80GECO Terpolymer >0.97∆ >1.03∆ >0.97∆ >0.69∆ >0.76∆ 0.28 0.48 >0.41∆ >1.10∆ 0.55

Carbon Black Hydrin H 100 phr >750∆ >870∆ >480∆ 330 290 90 140 140 160 300N-550 25 phr >5.17∆ >6.00∆ >3.31∆ 2.28 2.00 0.62 0.97 0.97 1.10 2.07

Calcium Carbonate Hydrin H 100 phr >110∆ >130∆ >140∆ >120∆ >120∆ 30 60 100 >160∆ >150∆

Calcium Carbonate 50 phr >0.76∆ >0.90∆ >0.97∆ >0.83∆ >0.83∆ 0.21 0.41 0.69 >1.10∆ >1.03∆

Plasticizer Hydrin H 100 phr >90∆ >110∆ >100∆ >80∆ >90∆ 30 50 70 >130∆ >110∆

Dioctyl Phthalate 10 phr >0.62∆ >0.76∆ >0.69∆ >0.55∆ >0.62∆ 0.21 0.34 0.48 >0.90∆ >0.76∆


Ethylene Acrylic Rubber (EEA)

thermoset rubber

Trade Names Manufacturer• Vamac DuPont

General DescriptionEthylene acrylic rubber is manufactured exclusively byDuPont under the tradename Vamac. Vamac is a ter-polymer of ethylene, methacrylate and a small quantityof a third monomer which contributes a carboxylatecure site. Raising the level of methacrylate monomerin the terpolymer blend improves oil resistance, at theexpense of low temperature flexibility. Ester plasticizersare used to improve low temperature properties, butcan be lost in heat aging or extracted by solvents athigh temperatures. These rubbers tend to stick to pro-cessing equipment and generally contain processingaids such as release agents. These products can becured with peroxide cure systems, although superiorproperties generally result from the use of multivalentdiamine cure systems. Ethylene acrylic rubber is com-monly reinforced with carbon black to obtain best per-formance properties.

General PropertiesEthylene acrylic rubbers have better heat resistanceand low temperature flexibility than polyacrylate rub-bers. Ethylene acrylic rubber also offers excellentresistance to water. This, coupled with its resistance toUV and ozone, give it excellent weathering resistance.These improvements are gained while offering equiva-lent oil resistance to polyacrylate rubber. Other lessnotable improvements include the improved oxidative,alkali and acid resistance of Vamac over polyacrylaterubbers. Ethylene acrylic rubber offers poor resistanceto non-mineral oil brake fluid, esters or ketones. Theydo, however, offer excellent resistance to diesel fuel,kerosene, ethylene glycol and water. Vamac has com-bustion products that are have a very low smoke den-sity, toxicity and corrosivity.

20

Typical Applications• Automotive Automotive fluid seals, gaskets,

boots, grommets, vibration mounts, pads, cam covers, filters, o-rings,door seals, hose covers

• Electrical Wire and cable insulation


Prism Primer - Prism 401/Prism 770Rubber Toughened CA - Prism 4204

• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105Polyurethane - Loctite 3951



Clay - IncreaseSilica - IncreaseAntistatic - Increase

• T80 Cure Increase


Ethylene Acrylic Rubber Vamac by DuPont








(MPa)

Cure System Usedin All FormulationsArmeen 18D 0.50 phrHVA-2 1.00 phrDiak #1 (All Except Grade G) 1.25 phrVulcup R (Grade G only) 1.50 phr

Control: Vamac B-124 100 phr 130 >330∆ >420∆ 130 140 30 110 170 190 1900.90 >2.28∆ >2.90∆ 0.90 0.97 0.21 0.76 1.17 1.31 1.31


uide for Bonding R

ubbers and TPEs

21

T80 Cure Vamac B-124 100 phr >400∆ >330∆ >420∆ 200 >370∆ <10 110 100 190 140Cured to 80% of Modulus at Full Cure >2.76∆ >2.28∆ >2.90∆ 1.38 >2.55∆ <0.07 0.76 0.69 1.31 0.97Carbon Black Vamac B-124 100 phr 470 >810∆ >970∆ 360 >740∆ 60 170 300 290 240

N-550 25 phr 3.24 >5.59∆ >6.69∆ 2.48 >5.10∆ 0.41 1.17 2.07 2.00 1.65

Clay Vamac B-124 100 phr 260 330 420 >320∆ 470 <10 150 280 >710∆ 260Dixie Clay 50 phr 1.79 2.28 2.90 >2.21∆ 3.24 <0.07 1.03 1.93 >4.90∆ 1.79

Silica Vamac B-124 100 phr >420∆ >790∆ >860∆ 330 >600∆ <10 150 170 330 190Hi Sil 233 15 phr >2.90∆ >5.45∆ >5.93∆ 2.28 >4.14∆ <0.07 1.03 1.17 2.28 1.31

Antistatic Vamac B-124 100 phr >320∆ >410∆ >420∆ >360∆ >360∆ 110 110 120 190 110Armostat 550 5 phr >2.21∆ >2.83∆ >2.90∆ >2.48∆ >2.48∆ 0.76 0.76 0.83 1.31 0.76


Ethylene Propylene Rubber (EPM, EPDM)

thermoset rubber

Trade Names Manufacturer• Nordel DuPont• Polysar EPDM Bayer• Royalene Uniroyal • Vistalon Exxon Chemical

General DescriptionEPDM is formed via the copolymerization of ethylene,propylene and a third comonomer in slurry or solution.The ethylene content of EPDM is typically 45 to 75%.The third comonomer is a non-conjugated diene. Thethree most prevalent in industry are dicyclopentadiene(DCPD), ethylidene norbornene (ENB) and 1,4 hexadi-ene (1,4 HD); the most commonly used being ENB.The polymerization of EPDM is catalyzed with a vana-dium halide, halogenated aluminum alkyl and, in somecases, an activator. Due to the poor mechanical prop-erties of unfilled EPDM, it typically requires reinforcingfiller levels greater than 70 phr to be of practical value.

General PropertiesEPDM is known for its superior resistance to ozoneand oxidation as well as its relatively low cost. The lowcost of compounded EPDM stems from its potential forhigh loading with low cost fillers. The aliphatic natureof the backbone results in the excellent weatherabilityof EPDM and also makes it extremely stable in color.Due to its non-polarity, EPDM has poor resistance tonon-polar chemicals, such as aliphatic, aromatic andchlorinated hydrocarbons, and high resistance to polarsolvents, such as ketones and alcohols. EPDM alsoexhibits good electrical properties due to the non-polarbackbone and the amorphous regions of the polymer.EPDM responds well to loading, developing high ten-sile, tear and abrasion properties, and is frequentlyfilled in high amounts (up to 700 phr). The mostprevalent filler is carbon black. Other fillers that arecommonly used are silicas, clays, talcs and groundwhitings. EPDM has favorable thermal properties.Heat resistance of 300oF (150oC) can be achieved withsulfur accelerated cure systems, while 350oF (177oC)can be achieved using peroxide cure systems. In addi-tion, peroxide cure systems result in EPDM rubberswith better compression set properties.

22

Typical Applications•Automotive Hoses, belts, cable insulation,

boots, seals, weatherstrip

• Consumer Garden hose, roof sheeting, ditchliners, coated fabrics

• Electronic Cable covers, underground wire,power cable insulation



• Medium Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204

• Low Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives Clay - Increase

Naphthenic Oil - DecreaseParaffinic Oil - Decrease



NOTES: = The addition of the indicated additive (or processing change) caused a statistically significant increase in the bond strength within 95% confi-dence limits.

= The addition of the indicated additive (or processing change) caused a statistically significant decrease in the bond strength within 95% confi-dence limits.


Ethylene Propylene Rubber Vistalon 2504 by Exxon Chemical, Nordel by DuPont, Royalene by Uniroyal





(MPa)

Cure System andReinforcements Usedin Vistalon 404N-550 25.00 phrZinc Oxide 5.00 phrVAROX DBPH-50 5.00 phrVANAX MBM 1.50 phrZinc Stearate 1.00 phr

Control: Vistalon 2504 100 phr 270 >680∆ >580∆ 230 240 80 140 130 110 110EPDM, ENB Terpolymer 1.86 >4.69∆ >4.00∆ 1.59 1.66 0.55 0.97 0.90 0.76 0.76The Loctite D

esign Guide for B

onding Rubbers and TP

Es23

T80 Cure Vistalon 2504 100 phr >270∆ >680∆ >680∆ >230∆ >500∆ <10 190 160 110 110Cured to 80% of Modulus at Full Cure >1.86∆ >4.69∆ >4.69∆ >1.59∆ >3.45∆ <0.07 1.31 1.1 0.76 0.76Vistalon 404 100 phr >270∆ >360∆ >350∆ 80 140 60 140 80 110 110EP Copolymer >1.86∆ >2.48∆ >2.41∆ 0.55 0.97 0.41 0.97 0.55 0.76 0.76

Nordel 1040 100 phr >390∆ >440∆ >490∆ 230 >350∆ 80 170 220 340 110EPDM, HD Terpolymer >2.69∆ >3.03∆ >3.38∆ 1.59 >2.41∆ 0.55 1.17 1.52 2.34 0.76

Royalene 301-T 100 phr >270∆ >210∆ >250∆ 230 >240∆ 80 40 130 110 110EPDM, DCPD Terpolymer >1.86∆ >1.45∆ >1.72∆ 1.59 >1.66∆ 0.55 0.28 0.90 0.76 0.76

Carbon Black Vistalon 2504 100 phr 510 >680∆ >410∆ 230 >540∆ 60 230 110 210 180N-550 65 phr 3.52 >4.69∆ >2.83∆ 1.59 >3.72∆ 0.41 1.59 0.76 1.45 1.24

Clay Vistalon 2504 100 phr >290∆ >270∆ >250∆ >280∆ >220∆ 80 240 250 >290∆ 250Dixie Clay 200 phr >2.00∆ >1.86∆ >1.72∆ >1.93∆ >1.52∆ 0.55 1.66 1.72 >2.00∆ 1.72

Vistalon 3708 100 phr 190 410 >580∆ 230 340 50 70 130 110 110EPDM, High Ethylene 1.31 2.83 >4.00∆ 1.59 2.34 0.34 0.48 0.90 0.76 0.76

Silica Vistalon 2504 100 phr 270 >530∆ >580∆ 230 240 <10 190 130 110 110Hi Sil 233 20 phr 1.86 >3.66∆ >366∆ 1.59 1.66 <0.07 1.31 0.90 0.76 0.76

Naphthenic Oil Vistalon 2504 100 phr >380∆ >510∆ >580∆ 120 160 40 100 80 110 60Naphthanic Oil 25 phr >2.62∆ >3.52∆ >4.00∆ 0.83 1.10 0.28 0.69 0.55 0.76 0.41

Paraffinic Oil Vistalon 2504 100 phr 100 >500∆ >580∆ 150 200 40 70 90 70 60Paraffinic Oil 25 phr 0.69 >3.45∆ >4.00∆ 1.03 1.38 0.28 0.48 0.62 0.48 0.41

Antistatic Vistalon 2504 100 phr >470∆ >400∆ >390∆ >400∆ >420∆ 50 110 130 110 70Armostat 550 5 phr >3.24∆ >2.76∆ >2.69∆ >2.76∆ >2.90∆ 0.34 0.76 0.90 0.76 0.48

Cure System andReinforcements Used inAll Other FormulationsN-550 25.00 phrZinc Oxide 5.00 phrCAPTAX 1.50 phrMethyl TUADS0 .80 phrStearic Acid 1.00 phr


Ethylene-Vinyl Acetate Copolymer (EVA)

thermoset rubber or thermoplastic elastomer

Trade Names Manufacturer• Elvax DuPont• Escorene Exxon Chemical• Evazote B.P. Chemicals• Ultrathene Quantum Chemicals

General DescriptionEthylene-vinyl acetate copolymer is formed through thecopolymerization of ethylene and vinyl acetate by con-tinuous bulk polymerization or solution polymerization.Since bulk polymerization produces polymer too low inmolecular weight to be useful in the rubber industry,solution polymerization is predominately used.Common grades have vinyl acetate contents rangingfrom 2% to 50%. As the vinyl acetate content changes,the crystallinity of the polymer decreases from 60% to10%, respectively. Since EVA is a thermoplastic, it canbe processed by methods common to thermoplasticssuch as extrusion, injection molding, blow molding,calendering, and rotational molding. Subsequentcrosslinking with a peroxide cure system can yieldthermoset EVA.

General PropertiesThe properties of ethylene-vinyl acetate copolymer varydepending primarily on the level of vinyl acetate in thecopolymer. At lower levels of vinyl acetate, the copoly-mer is a thermoplastic with properties similar to lowdensity polyethylene. As the vinyl acetate content isincreased, the copolymer takes on the performancecharacteristics of a thermoplastic elastomer until thecrystallinity drops so low that the copolymer forms asoft rubbery material with minimal physical strength.The copolymer containing high levels of vinyl acetate isprimarily used as a component in adhesives and coat-ings but can be vulcanized to obtain useful physicalproperties. As vinyl acetate content increases, poly-mer flexibility, toughness, solubility in organic solventsand clarity increase. The lowered crystallinity causedby the addition of the vinyl acetate contributes to gooddurability at lower temperatures and environmentalstress cracking resistance. The enhanced flexibility isaccompanied by lower softening point temperatures asthe vinyl acetate content increases, which limits theupper service temperatures of these materials. EVAhas good resistance to salt water and bases, but is notcompatible with strong oxidizers. Grades offering goodresistance to hydrocarbon greases are available, butEVA copolymers are generally readily soluble in a widerange of aliphatic, aromatic and chlorinated solvents.Grades offering good resistance to UV degradationand ozone are also available.

24

Typical Applications• Appliances Freezer door gaskets, convoluted

tube for vacuum cleaners

• Electrical Foams for static sensitive devices,

• Industrial Hoses, tubes

• Packaging Shrink wrap film

• Medical Disposable gloves, anaesthesia face masks and hoses

• Miscellaneous Adhesives, coatings, sealants, solar cell encapsulants, baby bottle nipples



• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Antistatic - Increase

High Vinyl Acetate - DecreaseLow Vinyl Acetate - Increase


Ethylene-Vinyl Acetate Copolymer Elvax by DuPont








(MPa)


None Used

Control: Elvax 560 100 phr 360 430 >470∆ 240 300 50 50 360 780 11015% Vinyl Acetate 2.48 2.97 >3.24∆ 1.66 2.07 0.34 0.34 2.48 5.38 0.76


uide for Bonding R

ubbers and TPEs

25

Antistatic Elvax 560 100 phr 510 550 >830∆ 530 >580∆ 10 10 220 780 <10Armostat 550 5 phr 3.52 3.79 >5.72∆ 3.66 >4.00∆ 0.07 0.07 1.52 5.38 <0.07

Elvax 150 100 phr 300 320 >830∆ 220 290 10 70 290 670 31032% Vinyl Acetate 2.07 2.21 >5.72∆ 1.52 2.00 0.07 0.48 2.00 4.62 2.14

Elvax 760 100 phr 250 >870∆ >660∆ 360 >410∆ 10 50 410 780 3209.3% Vinyl Acetate 1.72 >5.72∆ >4.55∆ 2.48 >2.83∆ 0.07 0.34 2.83 5.38 2.21


Fluorocarbon Rubber (FKM)

thermoset rubber

Trade Names Manufacturer• Dai-el Daikin• Fluorel 3M• Kalrez DuPont• Tecnoflon Ausimont• Viton DuPont Dow Elastomers

General DescriptionFluoroelastomers are produced by the polymerizationof various fluorine containing monomers. Commonlyused monomers include vinylidene fluoride, hexafluoro-propylene, per fluoro (methyl vinyl ether) and tetrafluo-roethylene. Generally, these monomers are used inconjunction with other non-fluorine containingmonomers which contribute cure sites and help alterthe fluorine content. The primary factors that influencethe cured performance characteristics are the fluorinecontent and the cure system used. Fluoroelastomersof varying fluorine content are divided into the follow-ing groups: A-66%; B-68%; F-70% and a fourth groupof specialty grades. The fluorine content of the rubberis controlled by monomer type and monomer ratio.Cure systems commonly used with fluoroelastomersinclude diamines, bisphenol and peroxide types.

General PropertiesFluoroelastomers are known for their outstanding ther-mal and chemical resistance. They are generally capa-ble of long-term service at temperatures of 392°F(200°C). It has been reported that some grades canwithstand intermittent exposure to temperatures ashigh as 644°F (340°C). These properties stem fromthe high polarity of the fluorine group, the high bondenergy of the fluorine-carbon bond and the completesaturation of the fluorocarbon backbone. The physicalproperties of fluorocarbon elastomers are dependenton the ionic attraction between adjacent fluorine andhydrogen atoms. This attraction leads to brittle pointtemperatures as high as -13°F (-25°C). This tendencytowards poor flexibility at low temperatures increasesas the fluorine content of the polymer increases.Fluorosilicones or specialty grades of fluorocarbonelastomers are generally used where good low temper-ature flexibility is required. Fluoroelastomers show verygood resistance to hydrocarbons, acids and chlorinat-ed solvents. To improve the oil resistance of fluoro-elastomers, the fluorine content can be increased.Increasing the fluorine content will decrease its resis-tance to polar solvents due to the increased polarity ofthe polymer. Fluoroelastomers can also be attacked by

26

bases and amines. To address these limitations, spe-cialty formulations are available with improved chemi-cal resistance.

Typical Applications•Aerospace Fuel seals, manifold gaskets, fuel

tank bladders, firewall seals

• Appliances Copier fuser rolls

• Automotive Shaft seals, fuel lines and seals,carburetor parts, gaskets

• Electronics Electrical connectors, wire andcable insulation

• Industrial Flue ducts, gaskets, hoses, oil well seals, pump linings


Surface Insensitive CA - Prism 401Prism Primer - Prism 401/Prism 770Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Light Curing Acrylic - Loctite 3105



Barium Sulfate - IncreaseSilica - IncreaseProcessing Aid - DecreaseAntistat - Decrease



Fluorocarbon Rubber Viton by DuPont Dow Elastomers and Fluorel by 3M







Cure System Usedin All FormulationsMaglite D 3.00 phrCalcium Hydroxide 6.00 phr

Control: Viton E-60C 100 phr >300∆ >300∆ 280 >330∆ >270∆ 70 120 130 >510∆ 130Group A: Dipolymer, 66% Fluorine >2.07∆ >2.07∆ 1.93 >2.28∆ >1.86∆ 0.48 0.83 0.90 >3.52∆ 0.90


uide for Bonding R

ubbers and TPEs

27

T80 Cure Viton E-60C 100 phr >300∆ >300∆ 280 >330∆ 270 70 120 130 >510∆ 130Cured to 80% of Modulus at Full Cure >2.07∆ >2.07∆ 1.93 >2.28∆ 1.86 0.48 0.83 0.90 >3.52∆ 0.90Viton B 100 phr >300∆ >300∆ >280∆ 200 >210∆ 70 110 130 >400∆ 130Group B: Terpolymer, 68% Fluorine >2.07∆ >2.07∆ >1.93∆ 1.38 >1.45∆ 0.48 0.76 0.90 >2.76∆ 0.90Fluorel 5730Q SMR-5 100 phr >280∆ >350∆ >280∆ 230 >270∆ 40 80 80 >510∆ 80Group F: High Fluorine, 70% Fluorine >2.93∆ >2.41∆ >1.93∆ 1.59 >1.86∆ 0.28 0.55 0.55 >3.52∆ 0.55

Carbon Black Viton E-60C 100 phr >440∆ >530∆ >520∆ >520∆ >560∆ 70 190 240 >830∆ 230MT N990 30 phr >3.03∆ >3.66∆ >3.59∆ >3.59∆ >3.86∆ 0.48 1.31 1.66 >5.72∆ 1.59

Barium Sulfate Viton E-60C 100 phr >240∆ >300∆ >280∆ >330∆ >270∆ 100 170 200 >510∆ 180Barium Sulfate 50 phr >1.66∆ >2.07∆ >1.93∆ >2.28∆ >1.86∆ 0.69 1.17 1.38 >3.52∆ 1.24

Silica Viton E-60C 100 phr >660∆ >750∆ >730∆ >690∆ >790∆ 70 210 310 >1060∆ 280Polyethylene Glycol 2.5 phr, Hi Sil 233 15 phr >4.55∆ >5.17∆ >5.03∆ >4.76∆ >5.45∆ 0.48 1.45 2.14 >7.31∆ 1.93Processing Aid Viton E-60C 100 phr >250∆ >300∆ >280∆ >330∆ >270∆ 70 120 130 >410∆ 110

Carnauba Wax 5 phr >1.72∆ >2.07∆ >1.93∆ >2.28∆ >1.86∆ 0.48 0.83 0.90 >2.83∆ 0.76

Processing Aid Viton E-60C 100 phr >120∆ >140∆ >150∆ >110∆ >140∆ 70 120 150 >170∆ 100Dynamar PPA-790 5 phr >0.83∆ >0.97∆ >1.03∆ >0.76∆ >0.97∆ 0.48 0.83 1.03 >1.17∆ 0.69

Antistatic Viton E-60C 100 phr >150∆ >200∆ >180∆ >160∆ >270∆ 50 100 >170∆ >360∆ 100Armostat 550 5 phr >1.03∆ >1.38∆ >1.24∆ >1.10∆ >1.86∆ 0.34 0.69 >1.17∆ >2.48∆ 0.69


(MPa)


Fluorosilicone Rubber (FVMQ)

thermoset rubber

Trade Names Manufacturer• FE Shinetsu Chemical Company• FSE General Electric• LS Dow Corning

General DescriptionFluorosilicone rubber has an inorganic silicone back-bone, comprised of siloxane linkages (silicon-oxygenbonds). This, coupled with the highly polar pendanttrifluoropropyl groups, give fluorosilicones a uniquecombination of properties. The siloxane backbone pro-vides superior flexibility at low temperatures comparedto other fluoroelastomers. The pendant trifluoropropylgroups make the elastomer extremely polar whichincreases its resistance to non-polar solvents. Siliconeelastomers have one pendant methyl group and onependant trifluoropropyl group for 40-90 mole % of thesilicon atoms on the backbone depending on the fluo-rine content of the monomers selected. A small per-cent of silicon atoms with a pendant vinyl group will beincorporated into the polymer chain to serve ascrosslink sites. Typically, it is required for fluorosili-cones to be reinforced with silica to obtain usefulphysical properties.

General PropertiesFluorosilicones are renowned for their fuel resistanceand utility in extreme temperature service environ-ments. The siloxane backbone results in a polymerwith excellent UV, ozone and thermal resistance. Themaximum recommended service temperature is inexcess of 392oF (200oC) for most grades with brittlepoints as low as -85oF (-65oC). This results in betterflexibility at low temperatures than fluorocarbon elas-tomers can offer. The polarity of the fluorosiliconeelastomer results in very good resistance to non-polarsolvents such as aliphatic and aromatic hydrocarbonscommonly used in fuels. In comparison to siliconerubbers, the primary advantage of fluorosilicone rub-bers is their exceptional resistance to non-polar sol-vents which would normally cause severe swelling ofthe PMVQ rubbers. On the other hand, the fluorosili-cone will have less resistance to polar solvents thanPMVQ rubbers.

28

Typical Applications• Automotive O-rings, seals

• Industrial Shaft seals, gaskets, molded goods, duct hoses

• Electronics Wire and cable insulation


Prism Primer - Prism 401/Prism 770

• Medium Rubber Toughened CA - Prism 4204Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Light Curing Acrylic - Loctite 3105

• Low Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951


Calcium Carbonate - IncreaseFluorosilicone Oil - Decrease



Fluorosilicone Rubber FSE 2620U by General Electric








(MPa)

Cure System andReinforcement Usedin All FormulationsDiCup R 2.00 phrAerosil 200 5.00 phr

Control: FSE 2620U 100 phr 60 >190∆ >240∆ 70 110 110 160 90 120 900.41 >1.31∆ >1.66∆ 0.48 0.76 0.76 1.10 0.62 0.83 0.62


uide for Bonding R

ubbers and TPEs

29

T80 Cure FSE 2620U 100 phr 60 230 >240∆ 70 110 80 160 60 120 80Cured to 80% of Modulus at Full Cure 0.41 1.59 >1.66∆ 0.48 0.76 0.55 1.10 0.41 0.83 0.55Carbon Black FSE 2620U 100 phr 80 210 >240∆ 120 120 110 240 90 120 120

N-550 25 phr 0.55 1.45 >1.66∆ 0.83 0.83 0.76 1.66 0.62 0.83 0.83

Calcium Carbonate FSE 2620U 100 phr 100 >190∆ >240∆ 90 110 170 160 90 190 110Calcium Carbonate 40 phr 0.69 >1.31∆ >1.66∆ 0.62 0.76 1.17 1.10 0.62 1.31 0.76

Fluorosilicone Oil FSE 2620U 100 phr 260 >130∆ >150∆ 50 80 110 160 <10 70 <10Fluorosilicone Oil 10 phr 1.79 >0.90∆ >1.03∆ 0.34 0.55 0.76 1.10 <0.07 0.48 <0.07

Silica FSE 2620U 100 phr 60 >190∆ >240∆ 70 110 110 160 90 120 90Aerosil 200 10 phr 0.41 >1.31∆ >1.66∆ 0.48 0.76 0.76 1.10 0.62 0.83 0.62


Halogenated Butyl Rubber (BIIR, CIIR)

thermoset rubber

Trade Names Manufacturer• Exxon Bromobutyl Exxon Chemical• Exxon Chlorobutyl Exxon Chemical• Polysar Bromobutyl Bayer • Polysar Chlorobutyl Bayer

General DescriptionHalogenated butyl rubber is created by the halogena-tion of butyl rubber with either bromine or chlorine.Bromine or chlorine is added to the butyl polymer at a1:1 molar ratio of halogen to isoprene. The addition ofthe halogen atoms to the butyl backbone increases thepolarity of the non-polar butyl rubber. The increase inpolarity yields rubber with better resistance to non-polar hydrocarbons and allows it to be blended withmore polar rubbers which contain unsaturation. As aresult, halobutyl rubbers can be covulcanized with nat-ural rubber, neoprene, styrene butadiene, nitrile,chlorosulfonated polyethylene, butyl, EPDM, andepichlorohydrin elastomers. Another benefit of halo-genation is that the allylic halogen structures formedfacilitate crosslinking by cure systems other than sulfur.This avoids the thermal limitations of sulfur cured butylrubber while retaining the low gas permeability andgood environmental resistance inherent in butyl rub-bers.

General PropertiesThe key performance feature of butyl rubber is itsextremely low permeability to gas and moisture. Thisis attributed to the long aliphatic polymer backboneand absence of bulky pendant groups which allow thepolymer chains to pack together very well. The prima-ry difference between halogenated butyl and butyl rub-bers is that the former can be crosslinked by a varietyof different cure systems, while the latter cannot. Thisresults in halogenated butyl rubbers having improvedthermal resistance over butyl rubbers because theycan be crosslinked with non-sulfur crosslink systems.Furthermore, the use of non-sulfur based cure systemsalso results in a purer rubber with less extractables.This makes halobutyl rubber compounds well suitedfor pharmaceutical closures. When formulated to offergood flex resistance, chlorobutyl covulcanizates withnatural rubber are widely used as innerliners for tube-less tires, especially in steel-belted radial tires.

30

Typical Applications• Automotive Tire innerliners, tire sidewalls, tire

tread components, hoses, engine mounts

• Electronics Electrical insulation

• Industrial Conveyor belts, curing bladders, membranes, tank linings, steam hose, diaphragms, gas bladders

• Medical Pharmaceutical closures

• Miscellaneous Bridge bearing pads, ball bladders,pond-liner membranes, roofing






Calcium Carbonate - IncreaseClay - IncreaseSilica - IncreaseAliphatic Oil - IncreaseNaphthenic Oil - DecreaseAntistatic - Increase for CAs



Halogenated Butyl Rubber Bromobutyl and Chlorobutyl by Exxon Chemical








(MPa)

Cure System Usedin All FormulationsStearic Acid 1.00 phrZinc Oxide 5.00 phrMaglite D 0.50 phrSulfur 2.00 phrTMTD 1.00 phr

Control: Bromobutyl 2244 100 phr >170∆ >190∆ >180∆ 80 110 40 80 60 130 70>1.17∆ >1.31∆ >1.24∆ 0.55 0.76 0.28 0.55 0.41 0.90 0.48


uide for Bonding R

ubbers and TPEs

31

T80 Cure Bromobutyl 2244 100 phr >170∆ >190∆ >180∆ 80 >130∆ 20 60 60 130 70Cured to 80% of Modulus at Full Cure >1.17∆ >1.31∆ >1.24∆ 0.55 >0.90∆ 0.14 0.41 0.41 0.90 0.48Chlorobutyl Chlorobutyl 1066 100 phr >130∆ >130∆ >130∆ 80 110 40 80 80 130 70

>0.90∆ >0.90∆ >0.90∆ 0.55 0.76 0.28 0.55 0.55 0.90 0.48

Carbon Black Bromobutyl 2244 100 phr 500 >560∆ >540∆ 140 230 50 130 140 130 130N-550 40 phr 3.45 >3.86∆ >3.72∆ 0.97 1.59 0.34 0.90 0.97 0.90 0.90

Calcium Carbonate Bromobutyl 2244 100 phr >140∆ >140∆ >140∆ 120 >110∆ 60 80 100 190 120Calcium Carbonate 100 phr >0.97∆ >0.97∆ >0.97∆ 0.83 >0.76∆ 0.41 0.55 0.69 1.31 0.83

Clay Bromobutyl 2244 100 phr 190 240 180 160 150 80 140 140 320 180Dixie Clay 100 phr 1.31 1.66 1.24 1.10 1.03 0.55 0.97 0.97 2.21 1.24

Silica Bromobutyl 2244 100 phr >260∆ >280∆ >320∆ 150 180 50 100 100 210 90Hi Sil 233 15 phr >1.79∆ >1.93∆ >2.21∆ 1.03 1.24 0.34 0.69 0.69 1.45 0.62

Aliphatic Oil Bromobutyl 2244 100 phr >300∆ >300∆ >260∆ 130 150 60 80 80 130 60Aliphatic Oil 20 phr >2.07∆ >2.07∆ >1.79∆ 0.90 1.03 0.41 0.55 0.55 0.90 0.41

Napthenic Oil Bromobutyl 2244 100 phr >130∆ >140∆ >140∆ 80 >110∆ 40 60 60 130 40Napthenic Oil 15 phr >0.90∆ >0.97∆ >0.97∆ 0.55 >0.76∆ 0.28 0.41 0.41 0.90 0.28

Processing Aid Bromobutyl 2244 100 phr 140 >180∆ >180∆ 100 130 30 80 60 130 70Struktol 40 MS 10 phr 0.97 >1.24∆ >1.24∆ 0.69 0.90 0.21 0.55 0.41 0.90 0.48

Antistatic Bromobutyl 2244 100 phr >170∆ >190∆ >180∆ >130∆ >140∆ 40 80 60 130 70Armostat 550 5 phr >1.17∆ >1.31∆ >1.24∆ >0.90∆ >0.97∆ 0.28 0.55 0.41 0.90 0.48


Hydrogenated Nitrile Rubber (H-NBR, HSN)

thermoset rubber

Trade Names Manufacturer• Therban Bayer• Zetpol Zeon Chemical

General DescriptionNitrile elastomer is produced through the emulsioncopolymerization of butadiene and acrylonitrilemonomer. Selective hydrogenation is then performed in a solvent with a noble metal catalyst to yield highlysaturated hydrogenated nitrile polymer.

General PropertiesDue to the aliphatic nature of the backbone, the ther-mal and chemical resistance are much improved overthat of nitrile rubber. Hydrogenated nitriles are knownfor their exceptional oil, gasoline and solvent resis-tance, tensile properties and extreme temperature per-formance. These properties, coupled with their goodabrasion and water resistance, make them suitable fora wide variety of applications. Hydrogenated nitrilesreact to filler loading, plasticizer loading and acryloni-trile content in much the same manner as unsaturatednitriles, except that the physical properties of hydro-genated nitriles are higher. The acrylonitrile contentdetermines the performance characteristics of the rub-ber. For superior tensile properties and oil resistance,a high level of acrylonitrile should be used. If low tem-perature performance is more important, a low acry-lonitrile level is more appropriate. Fillers can also beused to increase the performance of hydrogenatednitriles. The addition of carbon black and/or mineralfillers will increase the hardness at the cost ofdecreased elongation. These relationships occur in analmost linear fashion. Fillers can also be used toincrease the tensile strength of halogenated nitriles,however, the effect is not as clear. Normally, the ten-sile strength will increase to a maximum and begindecreasing. Another way to increase the strength, par-ticularly the abrasion resistance, is to carboxylate thepolymer. This produces carboxylic acid groups on thebackbone which form additional crosslink sites duringvulcanization. These additional crosslink sites increasethe crosslink density of the resulting nitrile elastomerwhich, consequently, increases the strength as well. Toincrease the heat resistance of nitrile elastomers,antioxidants may be permanently bound into the poly-mer molecule. Since the antioxidants cannot evapo-rate or be extracted by solvents, this dramatically pro-longs the useful life of the material.

32

Typical Applications•Automotive Lip seals, valve-stem seals, o-rings,

gaskets

• Industrial Oil field valve seals, o-rings, pistoncups, annular blowout preventors



• Medium Two-Part N o-Mix Acrylic - Depend 330Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Low Acrylonitrile - Decrease

Carbon Black - DecreaseSilica - IncreaseAntistat - Decrease


Surface Treatments• Prism Primer Decrease

Hydrogenated Nitrile Rubber Zetpol by Zeon Chemical








(MPa)

Cure System Usedin All FormulationsZinc Oxide 6.00 phrNaupard 445 1.50 phrVanox ZMTI 1.50 phrStruktol WB212 2.00 phrVul Cup 40KE 8.25 phr

Control: Zetpol 0020 100 phr >930∆ >1060∆ 280 >500∆ 770 50 150 220 1050 27050% Acrylonitrile, 10% unsaturation >6.41∆ >7.31∆ 1.93 >3.45∆ 5.31 0.34 1.03 1.52 7.24 1.86


uide for Bonding R

ubber and TPEs

33

T-80 Cure Zetpol 0020 100 phr >930∆ >1060∆ 280 >830∆ >990∆ 60 150 170 660 210Cured to 80% of Modulus at Full Cure >6.41∆ >7.31∆ 1.93 >5.72∆ >6.83∆ 0.41 1.03 1.17 4.55 1.45Low Acrylonitrile Zetpol 2000L 100 phr >760∆ >700∆ >960∆ >500∆ >770∆ 50 120 180 350 14037% Acrylonitrile, 5% unsaturation >5.24∆ >4.83∆ >6.62∆ >3.45∆ >5.31∆ 0.34 0.83 1.24 2.41 0.97

Carbon Black Zetpol 0020 100 phr >530∆ >500∆ >430∆ >500∆ >490∆ 40 100 110 480 170N-339 50 phr >3.66∆ >3.45∆ >2.97∆ >3.45∆ >3.38∆ 0.28 0.69 0.76 3.31 1.17

Silica Zetpol 0020 100 phr 710 >1240∆ 420 500 >770∆ 50 210 340 1050 370Hi Sil 255 50 phr 4.90 >8.55∆ 2.90 3.45 >5.31∆ 0.34 1.45 2.34 7.24 2.55

Plasticizer Zetpol 0020 100 phr >660∆ >1060∆ >750∆ >880∆ >770∆ 100 200 220 770 270Dibutyl Phthalate 25 phr >4.55∆ >7.31∆ >5.17∆ >6.07∆ >5.31∆ 0.69 1.38 1.52 5.31 1.86

Antistatic Zetpol 0020 100 phr 400 410 400 500 >400∆ 50 130 160 1050 270Armostat 550 5 phr 2.76 2.83 2.76 3.45 >2.76∆ 0.34 0.90 1.10 7.24 1.86


Melt Processible Rubber (MPR)


Trade Names Manufacturer• Alcryn DuPont

General DescriptionMelt processible rubber is a single phase polymeralloy. The first and only commercially available singlephase MPR was developed by DuPont and is knownexclusively by the trade name Alcryn. It is a blend ofethylene interpolymers, chlorinated polyolefins withpartial crosslinking of the ethylene components, plasti-cizers and fillers. Hydrogen bonding between the eth-ylene interpolymers and the chlorinated polyolefins isachieved by incorporating the proper functional groupson the ethylene interpolymer. The strong resultingattraction between the two polymer species enablesAlcryn to function as a single phase system. Alcryncan be processed by typical methods used for thermo-plastics such as extrusion, injection molding, calender-ing, vacuum forming and blow molding. Alcryn doesnot melt, but softens above 300oF (149oC) enough tobe molded with sufficient shear and pressure.

General PropertiesAlcryn is a very soft rubber with a suppleness and feelsimilar to vulcanized rubber. The key benefits offeredby Alcryn are oil resistance, good heat aging resis-tance and weatherability. Alcryn shows good resis-tance to hydrocarbon-based oils, as well as lithium-and silicone-based greases. In solvents and fuels,Alcryn has poor resistance to aromatic and chlorinatedstructures. Alcryn offers excellent property retentionwhen exposed to water and aqueous solutions of inor-ganic acids up to 212oF (100oC). However, mineralacids degrade Alcryn, especially at elevated tempera-tures. It has a (continuous recommended) servicetemperature ranging from -40 to 225oF (-40 to 107oC).This is typical of many of the non-vulcanized elas-tomers. While Alcryn exhibits good property retentionin this range, its low crystallinity and lack of a vulcan-izate phase make it prone to unacceptable compres-sion set at elevated temperatures. Alcryn is thermallystable below 360oF (182oC) but degrades above 400oF(204oC) to evolve hydrochloric acid. Alcryn has showngood property retention in both long-term exposure tooutdoor weathering and simulated aging environments.

34

Typical Applications• Construction Weatherstripping

• Electrical Wire and cable jackets, electrical boots

• Industrial Seals, gaskets, tubing, hoses, conveyor belts, coated fabrics

• Miscellaneous Suction cups, athletic field markers


Prism Primer - Prism 401/Prism 770Rubber Toughened CA - Prism 4204

• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105Polyurethane - Loctite 3951

• Low Acetoxy Silicone - Superflex 595

Effects of Formulation and Processing• Additives Titanium Dioxide - Increase

Colorant - Decrease


Melt Processible Rubber Alcryn by DuPont








(MPa)


None Required

Control: Alcryn 2070 NC 100 phr 250 >470∆ >590∆ 190 370 60 170 230 540 2401.72 >3.24∆ >4.07∆ 1.31 2.55 0.41 1.17 1.59 3.72 1.65


uide for Bonding R

ubbers and TPEs

35

Titanium Dioxide Alcryn 2070 NC 100 phr 400 >640∆ >590∆ 360 370 10 170 230 540 240TiO2 30 phr 2.76 >4.41∆ >4.07∆ 2.48 2.55 0.07 1.17 1.59 3.72 1.65

Colorant Alcryn 2070 NC 100 phr 210 >320∆ >390∆ 190 370 20 170 150 540 240PVC-based yellow dye 6 phr 1.45 >2.21∆ >2.69∆ 1.31 2.55 0.14 1.17 1.03 3.72 1.65

Antistatic Alcryn 2070 NC 100 phr 280 >360∆ >400∆ 370 >450∆ <10 170 230 360 240Armostat 550 5 phr 1.93 >2.48∆ >2.76∆ 2.55 >3.10∆ <0.07 1.17 1.59 2.48 1.65

Alcryn 1070 BK 100 phr 80 >680∆ >700∆ 180 250 40 140 150 130 2200.55 >4.69∆ >4.83∆ 1.24 1.72 0.28 0.97 1.03 0.90 1.52

Alcryn 2265 UT 100 phr 200 >550∆ >540∆ 240 300 30 170 120 200 2201.38 >3.79∆ >3.72∆ 1.65 2.07 0.21 1.17 0.83 1.38 1.52

Alcryn 3055 NC 100 phr 60 250 >250∆ 80 110 10 110 170 >270∆ 1500.41 1.72 >1.72∆ 0.55 0.76 0.07 0.76 1.17 >1.86∆ 1.03

Alcryn 2070 BK 100 phr 60 >400∆ 320 240 180 <10 150 120 350 1800.41 >2.76∆ 2.21 1.65 1.24 <0.07 1.03 0.83 2.41 1.24


Natural Rubber (NR)

thermoset rubber

International Types of Natural Rubber• Compo Crepe• Estate Brown Crepe• Flat Bark Crepe• Pale Crepe• Pure Smoked Blanket Crepe• Ribbed Smoked Sheet• Thick Blanket Crepe• Thin Brown Crepe

General DescriptionNatural rubber is created by processing the latex ofHevea brasiliensis. Hevea brasiliensis is a plant indige-nous to the Amazon valley and is the only known plantto produce high molecular weight linear polymer with100% cis 1,4 polyisoprene. The average dry weight oflatex is normally between 30 and 35%, typically rangingfrom 25 to 45%. To obtain the latex, the tree is"tapped". This is the process of cutting the bark backin thin sections so that the latex flows. The latex isthen collected, treated with a stabilizer to prevent pre-mature coagulation and brought to a processing cen-ter. The collection and processing technique deter-mines the grade of natural rubber. There are eight dif-ferent types of natural rubber which are then classifiedinto 35 technically specified international grades. Thegrade indicates the color, cleanliness, presence of bub-bles and uniformity of appearance.

General PropertiesRapid crystallization on stretching gives natural rubberits exceptional tensile strength, tear strength and abra-sion resistance properties. The tensile strength ofunfilled vulcanates ranges from 2,500 to 3,500 psi (17to 24 MPa), while fillers can increase that in excess of4,500 psi (31 MPa). The resilience of natural rubber isexcellent. At large strains, the fatigue life of naturalrubber is better than SBR. At low strains, the oppositeis true. The strength characteristics of natural rubberdecrease with increasing temperature. However, thestrength at temperature of natural rubber is normallysuperior to that of other elastomers. Natural rubber hasvery good processing properties and can be processedby a variety of different techniques. Conventional pro-cessing yields natural rubber with excellent initial prop-erties such as strength, abrasion resistance and fatigueresistance. The thermal resistance, creep and stress-relaxation properties of conventionally processed nat-ural rubber are not as desirable. To increase the ther-mal stability and improve the low compression set, an

36

efficient (EV) accelerated sulfur vulcanization systemcan be used. A semi-EV system can be used to helptrade off the increase in cost with the increase in per-formance.

Typical Applications• Industrial Hoses, conveyor belts, gaskets,

seals

• Engineering Springs, mountings, bushings

• Latex Gloves, condoms, carpet backing, threads



• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204



Calcium Carbonate - IncreaseClay - IncreaseAntistatic - Increase CA



Natural Rubber Standard Malaysian Rubber (SMR)








(MPa)

Cure System Usedin All FormulationsStearic Acid 1.00 phrZinc Oxide 3.00 phrAgerite Stalite S 1.50 phrSulfur 2.00 phrAccelerator MBTS 1.00 phrTMTD 0.10 phr

Control: SMR-5 SMR-5 100 phr 160 >300∆ >270∆ 130 140 30 50 40 230 401.10 >2.07∆ >1.86∆ 0.90 0.97 0.21 0.34 0.28 1.59 0.28


uide for Bonding R

ubbers and TPEs

37

T80 Cure SMR-5 100 phr 160 >300∆ >270∆ 130 140 40 50 40 230 40Cured to 80% of Modulus at Full Cure 1.10 >2.07∆ >1.86∆ 0.90 0.97 0.28 0.34 0.28 1.59 0.28SMR-10 SMR-10 100 phr >200∆ >300∆ >200∆ 130 140 30 50 40 70 40

>1.38∆ >2.07∆ >1.38∆ 0.90 0.97 0.21 0.34 0.28 0.48 0.28

Carbon Black SMR-5 100 phr 470 490 >470∆ 200 270 40 110 80 240 70N-550 25 phr 3.24 3.38 >3.24∆ 1.38 1.86 0.28 0.76 0.55 1.66 0.48

Calcium Carbonate SMR-5 100 phr 300 300 >390∆ 190 230 60 120 80 110 80Calcium Carbonate 100 phr 2.07 2.07 >2.69∆ 1.31 1.59 0.41 0.83 0.55 0.76 0.55

Clay SMR-5 100 phr 290 300 270 170 140 40 130 100 240 70McNamee Clay 100 phr 2.00 2.07 1.86 1.17 0.97 0.28 0.90 0.69 1.66 0.48

Silica SMR-5 100 phr 250 >300∆ 270 130 140 30 80 40 60 60Hi Sil 233 15 phr 1.72 >2.07∆ 1.86 0.90 0.97 0.21 0.55 0.28 0.41 0.41

Napthenic Oil SMR-5 100 phr 160 300 >270∆ 190 140 40 50 40 230 40Napthenic Oil 10 phr 1.10 2.07 >1.86∆ 1.31 0.97 0.28 0.34 0.28 1.59 0.28

Processing Aid SMR-5 100 phr 160 >300∆ >270∆ 130 140 30 40 40 50 40Polyethylene 1702 4 phr 1.10 >2.07∆ >1.86∆ 0.90 0.97 0.21 0.28 0.28 0.34 0.28

Antiozonant SMR-5 100 phr >280∆ >660∆ >270∆ 130 140 40 50 40 80 40Santoflex 13 3 phr >1.93∆ >4.55∆ >1.86∆ 0.90 0.97 0.28 0.34 0.28 0.55 0.28

Antistatic SMR-5 100 phr >240∆ 300 >270∆ >360∆ >280∆ 30 50 40 230 40Armostat 550 5 phr >1.66∆ 2.07 >1.86∆ >2.48∆ >1.93∆ 0.21 0.34 0.28 1.59 0.28


Neoprene (Polychloroprene, CR)

thermoset rubber

Trade Names Manufacturer• Baypren Bayer • Butaclor Enichem Elastomers• Neoprene DuPont

General DescriptionPolychloroprene is manufactured by the emulsion poly-merization of 2-chloro-1,3 butadiene monomer andcan be modified with sulfur and/or 2,3 dichloro-1,3-butadiene (ACR). The final structure and performanceproperties of the rubber are determined by three vari-ables: the addition of chain transfer agents during thepolymerization process; quenching the reactionthrough the addition of stabilizers; and breaking downthe gel formed during the polymerization processthrough peptization. Consequently, the manufacturingtechnique used will strongly influence the performanceproperties of the resulting rubber.

General PropertiesNeoprene offers better resistance to oxidation, ozone,weathering, water, oil and fuel than natural rubber.Although neoprene does not have any performanceproperties that are particularly outstanding, it doesoffer a good balance of various properties. The selec-tion of the gum stock will determine the range of prop-erties which can be attained in the final rubber. Thecure method and selection of type and level of fillers,plasticizers, processing aids and antioxidants willdetermine where the properties will fall in that range.The differences between the most common gradesused for molded assemblies can be explained in termsof their processing differences. Neoprene GN, forexample, is produced by polymerizing chloroprenemonomer in the presence of elemental sulfur. Theresulting polymer is then broken down through pepti-zation. This yields a rubber with the best tear strength,flex and resiliency. On the other hand, the T and Wtypes of neoprene cannot be peptized, but offer superi-or stability in the uncured form as well as better heataging and compression set resistance when cured.The T and W types of neoprene are similar but princi-pally differ in terms of nerve, with the T type havingmuch less than the W. This makes it much more suit-able for extrusion and calendering processes. In gen-eral, neoprenes also offer high tensile strength, goodabrasion resistance and less compression set.Neoprenes show good performance at low tempera-tures, although some types are more prone to crystal-

38

lization than others. In recent years, the use of neo-prene in automotive applications has decreased due tothe demand for performance at higher temperatures.

Typical Applications• Aerospace Gaskets, seals, deicers

• Automotive Timing belts, window gaskets, fuelhose covers, cable jacketing, sparkplug boots, hoses, joint seals

• Industrial Pipeline pigs, gaskets, hoses, power transmission belts, conveyor belts, escalator handrails

• Electronics Wire and cable jacketing

• Miscellaneous Sponge shoe soles, foam cushions



• Medium Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Neoprene GN - Increase

Neoprene TW - IncreaseCarbon Black - IncreaseCalcium Carbonate - IncreaseClay - IncreaseSilica - IncreaseAromatic Oil - DecreaseAntistat - Increase



Polychloroprene Rubber Neoprene by DuPont








(MPa)

Cure Systems Used in AllNeoprene W FormulationsStearic Acid 0.50 phrZinc Oxide 5.00 phrAgerite Stalite S 2.00 phrMagnesium Oxide 4.00 phrEthylene Thiourea 0.60 phrVanax NP 1.00 phr

Control: Neoprene W 100 phr >270∆ >310∆ >270∆ >260∆ >280∆ 60 50 60 200 80>1.86∆ >2.14∆ >1.86∆ >1.79∆ >1.93∆ 0.41 0.34 0.41 1.38 0.55


uide for Bonding R

ubbers and TPEs

39

T80 Cure Neoprene W 100 phr >270∆ >310∆ >340∆ >260∆ >280∆ 60 80 60 >430∆ 80Cured to 80% of Modulus at Full Cure >1.86∆ >2.14∆ >2.34∆ >1.79∆ >1.93∆ 0.41 0.55 0.41 >2.97∆ 0.55Neoprene GN Neoprene GN 100 phr >750∆ >580∆ >570∆ >350∆ >450∆ 60 110 90 630 130

>5.17∆ >4.00∆ >3.93∆ >2.41∆ >3.10∆ 0.41 0.76 0.62 4.34 0.90

Neoprene TW Neoprene TW 100 phr >790∆ >580∆ >510∆ >260∆ >280∆ 60 110 60 >440∆ 110>5.45∆ >4.00∆ >3.52∆ >1.79∆ >1.93∆ 0.41 0.76 0.41 >3.03∆ 0.76

Carbon Black Neoprene W 100 phr >800∆ >930∆ >600∆ >640∆ >630∆ 60 150 100 >980∆ 140N-550 25 phr >5.52∆ >6.41∆ >4.14∆ >4.41∆ >4.34∆ 0.41 1.03 0.69 >6.76∆ 0.97

Calcium Carbonate Neoprene W 100 phr >330∆ >380∆ >360∆ >350∆ >350∆ 60 130 110 >540∆ 130Calcium Carbonate 50 phr >2.28∆ >2.62∆ >2.48∆ >2.41∆ >2.41∆ 0.41 0.90 0.76 >3.72∆ 0.90

Clay Neoprene W 100 phr 340 420 350 380 380 80 180 310 >870∆ 330Dixie Clay 100 phr 2.34 2.90 2.41 2.62 2.62 0.55 1.24 2.14 >6.00∆ 2.28

Silica Neoprene W 100 phr >700∆ >990∆ >510∆ >580∆ >570∆ 60 130 110 >1190∆ 140Hi Sil 233 15 phr >4.83∆ >6.83∆ >3.52∆ >4.00∆ >3.93∆ 0.41 0.90 0.76 >8.21∆ 0.97

Aromatic Oil Neoprene W 100 phr >200∆ >250∆ >210∆ >260∆ >180∆ 40 50 60 >390∆ 60Aromatic Oil 20 phr >1.38∆ >1.72∆ >1.45∆ >1.79∆ >1.24∆ 0.28 0.34 0.41 >2.69∆ 0.41

Napthenic Oil Neoprene W 100 phr >270∆ >310∆ >270∆ >260∆ >280∆ 40 50 60 >940∆ 60Napthenic Oil 20 phr >1.86∆ >2.14∆ >1.86∆ >1.79∆ >1.93∆ 0.28 0.34 0.41 >6.48∆ 0.41

Antistatic Neoprene W 100 phr >270∆ >310∆ >360∆ >260∆ >280∆ 60 50 90 >460∆ 80Armostat 550 5 phr >1.86∆ >2.14∆ >2.48∆ >1.79∆ >1.93∆ 0.41 0.34 0.62 >3.17∆ 0.55


Nitrile Rubber (NBR, XNBR)

thermoset rubber

Trade Names Manufacturer• Breon B.P. Chemicals• Chemigum Goodyear • Humex Huels Mexicanos• Krynac Polysar International• Nipol Nippon Zeon• Nysen Copolymer Rubber • Perbunan Mobay

General DescriptionNitrile elastomers are produced via the copolymeriza-tion of butadiene and acrylonitrile monomers. Theproperties of the resulting elastomer are dependent onthe acrylonitrile/butadiene ratio of the elastomer. Theacrylonitrile content typically ranges from 15 to 50%.Although thiazole and sulfenamide cure systems (thecure systems typically used to process SBR and naturalrubber) can be used to vulcanize nitrile rubber, thiu-rams and peroxides are normally the preferred curesystems due to the increased thermal resistance.

General PropertiesNitriles are known for their superior high and low tem-perature performance and their exceptional oil, gaso-line and solvent resistance. These properties, coupledwith their good abrasion resistance, water resistanceand compression set make them suitable for a widevariety of applications. Their thermal resistance allowsthem to be used at service temperatures ranging from-49 to 300oF (-45 to 149oC). Since the monomer ratiohas a large effect on the properties of the elastomer,the ratio is dictated by its end use. For superior tensileproperties or oil resistance, a high level of acrylonitrileshould be used. If low temperature performance isparamount, a low acrylonitrile level is more appropriate.Fillers can also be used to increase the performance ofnitrile elastomers. The addition of carbon black and/ormineral fillers will increase the hardness at the cost ofdecreased elongation. These relationships occur in analmost linear fashion. Fillers can also be used toincrease the tensile strength of nitrile elastomers, how-ever, the effect is not as clear. Normally, the tensilestrength will increase to a maximum at approximately50 phr of reinforcing filler and begin decreasing.Another way to increase the strength, particularly theabrasion resistance, is to carboxylate the polymer toform carboxylated nitrile rubber (XNBR). This pro-duces carboxylic acid groups on the backbone whichform additional crosslink sites during vulcanization.These additional crosslink sites increase the crosslink

40

density of the resulting elastomer thereby increasing itsstrength. To increase the heat resistance of nitrileelastomers, antioxidants may be permanently boundinto the polymer molecule. Since the antioxidants can-not evaporate or be extracted by solvents, this dramati-cally prolongs the useful life of the material.Hydrogenated nitrile rubbers are also available whichcontain little or no unsaturated groups in the polymerbackbone. These elastomers show improved resis-tance to severe environments and are covered in moredetail in a separate chapter.

Typical Applications• Automotive Seals, hoses, tubing, belts,

electrical jacketing, gaskets

• Consumer Shoe products, coated fabrics,flooring

• Miscellaneous Adhesives, cements, PVC and ABS additive



• Medium Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Low Acrylonitrile - Decrease

Carboxylated - IncreaseCarbon Black - IncreaseClay - IncreaseSilica - IncreasePlasticizer - Decrease

• T80 Cure Decrease


Nitrile Rubber Chemigum by Goodyear








(MPa)

Cure System Usedin All FormulationsStearic Acid 1.50 phrZinc Oxide 5.00 phrAgerite Stalite S 1.50 phrRubber Maker’s Sulfur 1.75 phrAccelerator MBTS 1.50 phr

Control: Chemigum N687B 100 phr >260∆ >290∆ >290∆ 220 >240∆ 60 130 240 >240∆ 18033% Acrylonitrile >1.79∆ >2.00∆ >2.00∆ 1.52 >1.66∆ 0.41 0.90 1.66 >1.66∆ 1.24


uide for Bonding R

ubbers and TPEs

41

T80 Cure Chemigum N687B 100 phr >260∆ >290∆ >240∆ 220 >240∆ 60 130 150 240 180Cured to 80% of Modulus at Full Cure >1.79∆ >2.00∆ >1.66∆ 1.52 >1.66∆ 0.41 0.90 1.03 1.66 1.24Low Acrylonitrile Chemigum N984B 100 phr >260∆ >290∆ >260∆ >170∆ >200∆ 50 130 130 240 120

20% Acrylonitrile >1.79∆ >2.00∆ >1.79∆ >1.17∆ >1.38∆ 0.34 0.90 0.90 1.66 0.83

High Acrylonitrile Chemigum 386B 100 phr >260∆ >290∆ >290∆ 270 >300∆ 60 130 170 240 13040% Acrylonitrile >1.79∆ >2.00∆ >2.00∆ 1.86 >2.07∆ 0.41 0.90 1.17 1.66 0.90

Carboxylated Chemigum NX775 100 phr >280∆ >290∆ >290∆ 280 >270∆ 90 130 250 430 180>1.93∆ >2.00∆ >2.00∆ 1.93 >1.86∆ 0.62 0.90 1.72 2.97 1.24

Carbon Black Chemigum N687B 100 phr >360∆ >450∆ >370∆ >340∆ >370∆ 100 200 280 240 260FEF N-550 60 phr >2.48∆ >3.10∆ >2.55∆ >2.34∆ >2.55∆ 0.69 1.38 1.93 1.66 1.79

Clay Chemigum N687B 100 phr 300 >290∆ >330∆ >310∆ >300∆ 80 190 >330∆ 530 260Dixie Clay 120 phr 2.07 >2.00∆ >2.28∆ >2.14∆ >2.07∆ 0.55 1.31 >2.28∆ 3.66 1.79

Silica Chemigum N687B 100 phr >970∆ >950∆ >710∆ 670 >680∆ 60 190 240 240 180Hi Sil 233 30 phr >6.69∆ >6.55∆ >4.90∆ 4.62 >4.69∆ 0.41 1.31 1.66 1.66 1.24

Plasticizer Chemigum N687B 100 phr >210∆ >290∆ >250∆ >240∆ >200∆ 40 130 110 >240∆ >180∆

Dibutyl Phthalate 15 phr >1.45∆ >2.00∆ >1.72∆ >1.66∆ >1.38∆ 0.28 0.90 0.76 >1.66∆ >1.24∆

Processing Aid Chemigum N687B 100 phr >260∆ >290∆ >240∆ >220∆ >240∆ 70 130 180 >240∆ >180∆

Strurktol WB-16 2.5 phr >1.79∆ >2.00∆ >1.66∆ >1.52∆ >1.66∆ 0.48 0.90 1.24 >1.66∆ >1.24∆

Antistatic Chemigum N687B 100 phr >210∆ >290∆ >220∆ >220∆ >230∆ 70 100 150 240 120Armostat 550 5 phr >1.45∆ >2.00∆ >1.52∆ >1.52∆ >1.59∆ 0.48 0.69 1.03 1.66 0.83

The Loctite Design Guide for Bonding Rubber and TPE

Polyacrylate Rubber (ACM)

thermoset rubber

Trade Names Manufacturer• Europrene Enichem Elastomers America• Hycar B.F. Goodrich• HyTemp Zeon Chemical

General DescriptionPolyacrylate rubber is produced by polymerizing acrylicmonomers. Since acrylic monomer only contains a sin-gle double bond, polyacrylate rubber has a saturatedor aliphatic backbone. A comonomer is required if vul-canization is desired because, otherwise, the polymerwould lack the reactive species necessary forcrosslinking. Typically, an active halogen or epoxidecure system is used to vulcanize polyacrylate rubber.Varying the size of the pendant carboxylate group onthe polymer backbone has a dramatic effect on theproperties of the elastomer. Acrylate rubbers arecommonly reinforced with carbon black and/or silica toachieve acceptable physical properties.

General PropertiesPolyacrylate rubbers belong to the family of specialpurpose, oil resistant rubbers which have service tem-peratures in excess of 300oF (149oC). The aliphaticnature of the polymer backbone results in superiorperformance properties highlighted by resistance toUV, thermal degradation, ozone and oxidation. Thesize of the pendant carboxylate group has a significanteffect on the properties of the resulting polymer.Increasing the length of the alkane chain on the car-boxylate group improves the low temperature proper-ties of the polyacrylate. However, this decreases theoverall polarity of the polymer which, consequently,reduces its resistance to non-polar solvents. Animportant characteristic of polyacrylate rubbers is com-patibility with sulfur-bearing, extreme-pressure gearlubricants. The tear strength and abrasion resistanceof polyacrylate rubbers are not exemplary, while theflame resistance and resistance to acids and bases arepoor.

42

Typical Applications• Aerospace Rocket propellant binders

• Automotive Automotive fluid seals, high pressure hoses, seals, gaskets, boots

• Miscellaneous Adhesives, caulks, hot melts


Surface Insensitive CA - Prism 401Prism Primer - Prism 401/Prism 770Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105

• Low Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives Medium Alkane Chain - Decrease

Long Alkane Chain - DecreaseCarbon Black - IncreaseSynthetic Graphite - IncreaseClay - IncreaseSilica - IncreasePlasticizer - Decrease



Polyacrylate Rubber HyTemp by Zeon Chemical








(MPa)


NPC-50 1.50 phrSodium Stearate 1.00 phr

Control: HyTemp 4051 100 phr >80∆ >80∆ >70∆ >70∆ >90∆ <10 60 >70∆ >110∆ 40Short Alkane Chain >0.55∆ >0.55∆ >0.48∆ >0.48∆ >0.62∆ <0.07 0.41 >0.48∆ >0.76∆ 0.28


uide for Bonding R

ubbers and TPEs

43

T80 Cure HyTemp 4051 100 phr >80∆ >80∆ >90∆ >90∆ >110∆ 10 70 >70∆ >110∆ 40Cured to 80% of Modulus at Full Cure >0.55∆ >0.55∆ >0.62∆ >0.62∆ >0.76∆ 0.07 0.48 >0.48∆ >0.76∆ 0.28Medium Alkane Chain HyTemp 4052 100 phr >50∆ >50∆ >50∆ >50∆ >50∆ <10 50 >40∆ >80∆ 40

>0.34∆ >0.34∆ >0.34∆ >0.34∆ >0.34∆ <0.07 0.34 >0.28∆ >0.55∆ 0.28

Long Alkane Chain HyTemp 4054 100 phr >40∆ >50∆ >60∆ >30∆ >50∆ <10 40 >40∆ >80∆ 20>0.28∆ >0.34∆ >0.41∆ >0.21∆ >0.34∆ <0.07 0.28 >0.28∆ >0.55∆ 0.14

Carbon Black HyTemp 4051 100 phr >440∆ >370∆ >490∆ >380∆ >450∆ <10 110 110 350 60N-550 25 phr >3.03∆ >2.55∆ >3.38∆ >2.62∆ >3.10∆ <0.07 0.76 0.76 2.41 0.41

Synthetic Graphite HyTemp 4051 100 phr >120∆ >140∆ >140∆ >130∆ >140∆ <10 80 >110∆ >200∆ 70A99 Graphite 20 phr >0.83∆ >0.97∆ >0.97∆ >0.90∆ >0.97∆ <0.07 0.55 >0.76∆ >1.38∆ 0.48

Clay HyTemp 4051 100 phr >210∆ >200∆ >210∆ >200∆ >220∆ 20 90 110 >280∆ 90Carbowax 3350 3 phr, Dixie Clay 50 phr >1.45∆ >1.38∆ >1.45∆ >1.38∆ >1.52∆ 0.14 0.62 0.76 >1.93∆ 0.62

Silica HyTemp 4051 100 phr >140∆ >130∆ >120∆ >140∆ >160∆ <10 60 >120∆ >210∆ 40Carbowax 3350 3 phr, Diethylene Glycol 2 phr, Hi Sil 233 15 phr >0.97∆ >0.90∆ >0.83∆ >0.97∆ >1.10∆ <0.07 0.41 >0.83∆ >1.45∆ 0.28Plasticizer HyTemp 4051 100 phr >60∆ >70∆ >70∆ >70∆ >70∆ <10 40 30 >100∆ 20

Paraplex G-25 15 phr >0.41∆ >0.48∆ >0.48∆ >0.48∆ >0.48∆ <0.07 0.28 0.21 >0.68∆ 0.14Processing Aid HyTemp 4051 100 phr >80∆ >80∆ >80∆ >70∆ >90∆ 10 60 >70∆ >110∆ 40

Vanfre A1-2 5 phr >0.55∆ >0.55∆ >0.55∆ >0.48∆ >0.62∆ 0.07 0.41 >0.48∆ >0.76∆ 0.28Antistatic HyTemp 4051 100 phr >60∆ >80∆ >90∆ >70∆ >90∆ 20 60 >70∆ >130∆ 40

Armostat 550 5 phr >0.41∆ >0.55∆ >0.62∆ >0.48∆ >0.62∆ 0.14 0.41 >0.48∆ >0.90∆ 0.28


Polyisoprene (IR)

thermoset rubber

Trade Names Manufacturer• Isolene Hardman• Natsyn Goodyear• Nipol Goldsmith and Eggleton• SKI-3 Alcan

General DescriptionPolyisoprene is formed via the polymerization of iso-prene in a hydrocarbon solution. When the isoprenemonomer is added to the backbone, it can be added ineither an R or S configuration. As a result, the poly-merization addition can proceed in several differentways. In isotactic addition, the monomer groups areexclusively added in the same configuration(RRRRRR). In syndiotactic addition, the monomergroups are added to the backbone in alternating con-figurations (RSRSRS). Finally, in atactic addition, theaddition is random (RSSSRRS). Consequently, in orderto create a stereoregular polymer matrix which wouldhave physical properties similar to NR, a stereospecificcatalyst is required. This stereospecific catalyst, Al-Ti,was developed in 1960 which resulted in the first com-mercially viable synthetic polyisoprene.

General PropertiesNatural rubber and synthetic isoprene both have hightensile properties, good hysteresis and good hot tearproperties. The main advantages that synthetic poly-isoprenes have over natural rubbers are their increasedprocess control and processability. These processcharacteristics arise from the fact that natural rubber isharvested from a natural source while synthetic poly-isoprene is produced using a highly controlled manu-facturing process. The primary processing benefitsoffered by synthetic isoprene are its increased pro-cessing speeds and extrusion values. Other advan-tages of synthetic polyisoprene are that it does notcontain water-sensitive residues or contaminants, andit cures more consistently. In addition, synthetic poly-isoprene can be used at a higher loading than naturalrubber in SBR and EPDM blends. The disadvantagesof synthetic polyisoprene are its decreased greenstrength, cure speed and aging properties when com-pared to NR.

44

Typical Applications• Automotive Tires, motor mounts, gaskets,

bushings, hoses, coatings, tubes, belts

• Consumer Rubber bands, baby bottle nipples, footwear, sporting goods, fabric threads

• Miscellaneous Adhesives, conveyors



• Medium Light Curing Acrylic - Loctite 3105



Calcium Carbonate - IncreaseClay - Decrease CAClay - Increase Silicones and AcrylicsNaphthenic Oil - DecreaseAntioxidant - DecreaseAntistatic - Decrease



Polyisoprene Natsyn by Goodyear








(MPa)

Cure System Usedin All FormulationsStearic Acid 1.00 phrZinc Oxide 3.00 phrAgerite Superlite 1.50 phrSulfur 2.00 phrDurax 1.00 phrTMTM 0.20 phr

Control: Natsyn 2200 >240∆ >240∆ >290∆ >250∆ >200∆ 50 60 50 100 40>1.66∆ >1.66∆ >2.00∆ >1.72∆ >1.38∆ 0.34 0.41 0.34 0.69 0.28


uide for Bonding R

ubbers and TPEs

45

T80 Cure Natsyn 2200 100 phr >270∆ >300∆ >290∆ >250∆ >290∆ 50 60 40 100 30Cured to 80% of Modulus at Full Cure >1.86∆ >2.07∆ >2.00∆ >1.72∆ >2.00∆ 0.34 0.41 0.28 0.69 0.21Carbon Black Natsyn 2200 100 phr >450∆ >480∆ >480∆ >370∆ 360 60 90 70 100 80

N-550 25 phr >3.10∆ >3.31∆ >3.31∆ >2.55∆ 2.48 0.41 0.62 0.48 0.69 0.55

Calcium Carbonate Natsyn 2200 100 phr >190∆ >240∆ >290∆ >250∆ >200∆ 70 110 70 >280∆ 90Calcium Carbonate 100 phr >1.31∆ >1.66∆ >2.00∆ >1.72∆ >1.38∆ 0.48 0.76 0.48 >1.93∆ 0.62

Clay Natsyn 2200 100 phr 140 240 180 100 120 60 120 100 220 70Dixie Clay 100 phr 0.97 1.66 1.24 0.69 0.83 0.41 0.83 0.69 1.52 0.48

Silica Natsyn 2200 100 phr >240∆ >240∆ >290∆ 170 >150∆ 50 70 60 100 40Hi Sil 233 15 phr >1.66∆ >1.66∆ >2.00∆ 1.17 >1.03∆ 0.34 0.48 0.41 0.69 0.28

Napthenic Oil Natsyn 2200 100 phr >240∆ >240∆ >290∆ 130 >200∆ 40 40 40 40 30Napthenic Oil 25 phr >1.66∆ >1.66∆ >2.00∆ 0.90 >1.38∆ 0.28 0.28 0.28 0.28 0.21

Antioxidant Natsyn 2200 100 phr >240∆ >240∆ >290∆ >250∆ >200∆ 40 40 40 100 40Venox 2-AZ 2 phr >1.66∆ >1.66∆ >2.00∆ >1.72∆ >1.38∆ 0.28 0.28 0.28 0.69 0.28

Antistatic Natsyn 2200 100 phr >240∆ >240∆ >210∆ >220∆ >280∆ 30 30 10 70 30Armostat 550 5 phr >1.66∆ >1.66∆ >1.45∆ >1.52∆ >1.93∆ 0.21 0.21 0.07 0.48 0.21


Polyolefin Elastomers (POE)


Trade Names Manufacturer• Engage DuPont Dow Elastomers• Hercuprene J-Von• Sarlink DSM

General DescriptionPolyolefin elastomers can be divided into two majorcategories. The first type is a two-phase polymer sys-tem consisting of a thermoplastic matrix, such aspolypropylene or polyethylene, with a dispersed secondphase of an unvulcanized rubber, such as EPDM, nat-ural rubber and SBR. Hercuprene is an example ofthis type of polyolefin elastomer. The second categoryis a family of ethylene-octene copolymers. They areproduced by DuPont Dow Elastomers via a proprietarypolymerization technique and marketed under thetradename Engage. These systems can be vulcanizedusing peroxides, silanes or irradiation to yield improvedhigh temperature properties.

General PropertiesPolyolefin elastomers are characterized by excellentlow temperature properties, clarity and crack resis-tance. Engage has a brittle point below -60oF (-76oC) for formulations with hardnesses ranging from60 to 90 Shore A. In addition, they offer excellent UV,ozone and weatherability resistance. They also offergood resistance to polar fluids. Resistance to non-polar fluids is poor due to the aliphatic nature of thepolymer backbone. Room temperature physical prop-erties are good. Like most thermoplastic systems, thephysical properties at temperature decrease withincreasing temperature. This limitation can beaddressed by vulcanizing the polymer. However, thisextra processing step mitigates the economic benefitsof the polyolefin elastomers over conventional vulcan-ized rubber. Polyolefin elastomers typically have verylow specific gravities and can be utilized in applica-tions where reducing weight is critical.

46

Typical Applications• Automotive Rub strips, fascias, bumper covers,

molding, trim

• Electrical Wire and cable insulation and jacketing



• Medium Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951


Effects of Formulation and Processing• Additives Antistatic - Decrease


Polyolefin Elastomer Engage by DuPont Dow Elastomers








(MPa)

Cure System Used in AllFormulations

None Required

Engage EP 8100 270 >540∆ >440∆ 210 280 70 200 210 >540∆ 2801.86 >3.72∆ >3.03∆ 1.45 1.93 0.48 1.38 1.45 >3.72∆ 1.93


uide for Bonding R

ubbers and TPEs

47

Engage EP 8150 270 >550∆ >500∆ 200 230 70 150 210 400 2101.86 >3.79∆ >3.45∆ 1.38 1.59 0.48 1.03 1.45 2.76 1.45

Engage EP 8200 310 >460∆ >460∆ 180 >270∆ 60 190 170 >560∆ 2802.14 >3.17∆ >3.17∆ 1.24 >1.86∆ 0.41 1.31 1.17 >3.86∆ 1.93

Engage EP 8500 230 >380∆ >470∆ 190 200 60 130 180 330 1501.59 >2.62∆ >3.24∆ 1.31 1.38 0.41 0.90 1.24 2.28 1.03

Antistatic EP 8500 100 phr 230 >380∆ >470∆ 70 200 <10 70 180 330 60Armostat 550 5 phr 1.59 >2.62∆ >3.24∆ 0.48 1.38 <0.07 0.48 1.24 2.28 0.41


Poly(propylene oxide) Rubber (GPO)

thermoset rubber

Trade Names Manufacturer• Parel Zeon Chemical

General DescriptionPoly(propylene oxide) rubber is formed by the copoly-merization of propylene oxide and allyl glycidyl ether.The allyl glycidyl ether monomer is present at lowerquantities (approximately 6% by weight) and providescrosslink sites for the polymer via the unsaturatedgroup. The propylene oxide provides flexibility in thebackbone in several ways. First, the presence of theoxygen atom in the backbone aids polymer chain flexi-bility. Secondly, the propylene oxide monomer canpolymerize with itself to form atactic as well as isotac-tic regions. The combination of these two regionsresults in irregular packing of the polymer chainswhich reduces crystallinity. Another factor contributingto the flexibility of PPO is the bulky allyl glycidyl etherpendant group which further reduces crystallinity bydisrupting ordered packing of the polymer. Sulfur-based curative systems are generally used with thesepolymers, even though peroxides are capable of takingadvantage of the unsaturation. Peroxide cure systemstend to cause chain scission, resulting in unacceptableproperties.

General PropertiesThe most notable characteristic of poly(propyleneoxide) rubber is its ability to offer excellent hysteresisproperties and dynamic properties over a wide temper-ature range. Even after exposure to elevated tempera-tures as high as 302oF (150oC) for a week, the dynam-ic properties of GPO rubber remain excellent. Typically,they offer good low temperature flexibility, good ozoneresistance, fair fuel and oil resistance and good prop-erties retention at high temperatures. GPO rubber hasfair resistance to hydrocarbon fuels and oils and goodhydrolysis and swelling resistance in polar solventssuch as water and alcohol. GPO rubber does not haveoutstanding physical properties and tends to have poorcompression set and flame resistance. The limitedphysical properties of GPO rubber can be improvedusing reinforcing fillers, such as carbon black or silica.However, the poor compression set of GPO rubber is afunction of the sulfur crosslinks and cannot be easilyremedied.

48

Typical Applications• Automotive Motor mounts, body mounts, sus-

pension bushings, dust seals, boots






Aromatic Oil - DecreasePlasticizer - Decrease

• T80 Cure Decrease


Poly(propylene oxide) Rubber Parel 58 by Zeon Chemical








(MPa)

Cure System Usedin All FormulationsZinc Oxide 5.00 phrSulfur 1.25 phrTMTM 1.50 phrMBT 1.50 phr

Control: Parel 58 Parel 58 100 phr >120∆ >120∆ >110∆ >120∆ >110∆ 40 50 50 >170∆ 120>0.83∆ >0.83∆ >0.76∆ >0.83∆ >0.76∆ 0.28 0.34 0.34 >1.17∆ 0.83


uide for Bonding R

ubbers and TPEs

49

T80 Cure Parel 58 100 phr >80∆ >90∆ >90∆ >80∆ >90∆ 40 50 50 >150∆ >110∆

Cured to 80% of Modulus at Full Cure >0.55∆ >0.62∆ >0.62∆ >0.55∆ >0.62∆ 0.28 0.34 0.34 >1.03∆ >0.76∆

Carbon Black Parel 58 100 phr >330∆ >350∆ >360∆ >410∆ >350∆ 50 100 70 170 160N550 25 phr >2.28∆ >2.41∆ >2.48∆ >2.83∆ >2.41∆ 0.34 0.69 0.48 1.17 1.10

Aromatic Oil Parel 58 100 phr >90∆ >90∆ >90∆ >90∆ >80∆ 40 50 50 >140∆ >120∆

Aromatic Oil 20 phr >0.62∆ >0.62∆ >0.62∆ >0.62∆ >0.55∆ 0.28 0.34 0.34 >0.97∆ >0.83∆

Plasticizer Parel 58 100 phr >80∆ >80∆ >90∆ >90∆ >80∆ 40 50 50 >120∆ >90∆

Dioctyl Phthalate 15 phr >0.55∆ >0.55∆ >0.62∆ >0.62∆ >0.55∆ 0.28 0.34 0.34 >0.83∆ >0.62∆

Antistatic Parel 58 100 phr >110∆ >100∆ >110∆ >100∆ >100∆ 50 70 50 >170∆ >120∆

Armostat 550 5 phr >0.76∆ >0.69∆ >0.76∆ >0.69∆ >0.69∆ 0.34 0.48 0.34 >1.17∆ >0.83∆


Polysulfide Rubber

thermoset rubber

Trade Names Manufacturer• LP Morton Thiokol• Thiokol Morton Thiokol

General DescriptionThe key factor that distinguishes polysulfide rubbersfrom other rubbers is the high sulfur content of thepolymer backbone. This results in a very flexible, virtu-ally impermeable rubber. Polysulfide elastomers areproduced by the condensation reaction of an organicdihalide with sodium tetrasulfide. Examples of organicdihalides used include ethylene dichloride and di-2-chloroethyl ether. Commercial grades vary in sulfurcontent from 37 to 84%; the sulfur content of theresulting rubber being dependent on the basemonomer selected. In addition to the performancebenefits offered by the high sulfur content of the back-bone, the various reactive sites on the polymer back-bone facilitate crosslinking by a wide variety of meth-ods. Generally, a metal oxide or peroxide is used tocrosslink the terminal thiol groups, although terminalchlorine and hydroxide groups can also be used.Polysulfide polymers are available in viscosities rangingfrom pourable liquids to millable gum stock. Thestrong odor of polysulfides, coupled with the need topeptize some of the gum rubber stocks, can makethem difficult to process.

General PropertiesThe key performance benefits of polysulfide elastomersare their outstanding chemical resistance and virtualimpermeability to most gases, hydrocarbon solventsand moisture. This, coupled with their high flexibilityand long-term resistance to both polar and non-polarsolvents, makes them especially well suited for sealingapplications that require exceptional barrier and resis-tance properties. Other performance characteristicsinclude good performance at low temperatures andgood resistance to UV and ozone. Polysulfide elas-tomers do not have very good compression set resis-tance and have fair physical properties. The limitedphysical properties can be addressed by compoundingthem with other rubbers, such as polychloroprene.Polysulfide rubber has a recommended service temper-ature of approximately -40 to 250oF (-40 to -121oC).

50

Typical Applications• Aerospace Propellant binders, gas bladders,

sealants, valves

• Automotive Gaskets, rubber washers

• Construction Building caulk, window glazing






Clay - IncreaseSilica - IncreaseAromatic Oil - DecreaseAntistatic - Increase






Polysulfide Rubber Thiokol by Morton Thiokol





(MPa)

Polysulfide Cure SystemsThiokol FA formulationsStearic Acid 0.5 phrMTBS 0.3 phrDPG 0.1 phrZinc Oxide 10.0 phrMaglite D 4.0 phr

Control: Thiokol FA 100 phr 150 >180∆ >170∆ >190∆ >140∆ 80 150 110 >240∆ 160Linear structure 1.03 >1.24∆ >1.17∆ >1.31∆ >0.97∆ 0.55 1.03 0.76 >1.66∆ 1.10


uide for Bonding R

ubbers and TPEs

51

T80 Cure Thiokol FA 100 phr >270∆ >270∆ >230∆ >280∆ >290∆ 80 150 140 >370∆ >160∆

Cured to 80% of Modulus at Full Cure >1.86∆ >1.86∆ >1.59∆ >1.93∆ >2.00∆ 0.55 1.03 0.97 >2.55∆ >1.10∆

Thiokol ST Thiokol ST 100 phr >180∆ >180∆ >170∆ >190∆ >180∆ 70 150 150 >300∆ 60Branched structure >1.24∆ >1.24∆ >1.17∆ >1.31∆ >1.24∆ 0.48 1.03 1.03 >2.07∆ 0.41

Carbon Black Thiokol FA 100 phr >390∆ >380∆ >470∆ >470∆ >500∆ 110 250 290 240 360N-550 100 phr >2.69∆ >2.62∆ >3.24∆ >3.24∆ >3.45∆ 0.76 1.72 2.00 1.66 2.48

Clay Thiokol FA 100 phr 250 >290∆ 310 280 310 130 230 260 >460∆ 290Dixie Clay 100 phr 1.72 >2.00∆ 2.14 1.93 2.14 0.90 1.59 1.79 >3.17∆ 2.00

Silica Thiokol FA 100 phr 330 340 290 350 330 110 240 310 420 270Hi Sil 233 100 phr 2.28 2.34 2.00 2.41 2.28 0.76 1.66 2.14 2.90 1.86

Aromatic Oil Thiokol FA 100 phr >90∆ 100 80 110 90 60 110 60 >140∆ >70∆

Aromatic Oil 15 phr >0.62∆ 0.69 0.55 0.76 0.62 0.41 0.76 0.41 >0.97∆ >0.48∆

Antistatic Thiokol FA 100 phr >190∆ 180 >220∆ >190∆ >220∆ 80 150 180 >340∆ 180Armostat 550 5 phr >1.31∆ 1.24 >1.52∆ >1.31∆ >1.52∆ 0.55 1.03 1.24 >2.34 1.24

Thiokol ST formulationsStearic Acid 1.0 phrCalcium Hydroxide 1.0 phrZinc Peroxide 5.0 phrMaglite D 4.0 phr


Silicone-Modified EPDM

thermoset rubber

Trade Names Manufacturer• Royaltherm Uniroyal Chemical

General DescriptionSilicone-modified EPDM represents a unique combina-tion of the benefits offered by silicone and EPDM rub-bers. The inorganic polysiloxane backbone of the sili-cone contributes low temperature flexibility and hightemperature resistance, while the EPDM contributesgood mechanical properties. The resulting polymer hasbetter physical properties than a silicone and betterthermal resistance and strength at temperature thanEPDM. Silicone-modified EPDM can be vulcanized bysulfur-based curatives or peroxide cure systems.Peroxide cure systems are generally utilized to maxi-mize heat resistance and compression set resistance.Specialty purpose base compounds offering non-halo-gen flame retardancy, translucency, FDA approval orutility in sponge applications are also available.

General PropertiesThe performance properties of silicone-modified EPDMare best understood in terms of the properties of eachof the pure components. In general, it has the goodmechanical properties of EPDM rubber with theimproved thermal resistance of silicone elastomers.However, there are some trade-offs. For example, theservice life at temperatures ranging from 300 to 400oF(149 to 204oC) is an order of magnitude longer thanthat achieved by EPDM and at least an order of mag-nitude less than that achieved by silicone. Silicone-modified EPDM offers much better strength retentionthan silicone when exposed to steam at 327oF (164oC),but only slightly less than EPDM. Tensile strength andabrasion resistance follow the same trend. Silicone-modified EPDM also offers the excellent chemicalresistance and wet electrical properties of EPDM. Thehot tear strength of silicone-modified EPDM exhibits asynergistic effect between the two phases since it hashot tear strengths superior to that of either of its purecomponents.

52

Typical Applications• Automotive Ignition cables, seals, gaskets,

weatherstripping

• Industrial Steam hoses, gaskets, seals






Silica - IncreasePlasticizer - DecreaseAntistatic - Decrease



Silicone Modified EPDM Royaltherm by Uniroyal Chemical Company








(MPa)

Cure System Usedin All FormulationsStearic Acid 1.50 phrZinc Oxide 4.00 phrDi Cup 40C 7.00 phr

Control: Royaltherm 1411 >380∆ >350∆ >310∆ >270∆ >250∆ 40 110 110 >350∆ 120>2.62∆ >2.41∆ >2.14∆ >1.86∆ >1.72∆ 0.28 0.76 0.76 >2.41∆ 0.83


uide for Bonding R

ubbers and TPEs

53

T80 Cure Royaltherm 1411 100 phr >380∆ >420∆ >420∆ >270∆ >250∆ 40 110 110 >350∆ 100Cured to 80% of Modulus at Full Cure >2.62∆ >2.90∆ >2.90∆ >1.86∆ >1.72∆ 0.28 0.76 0.76 >2.41∆ 0.69Royaltherm 1721 Royaltherm 1721 100 phr >260∆ >350∆ >310∆ >270∆ >250∆ 60 160 140 350 160

Improved heat resistance >1.79∆ >2.41∆ >2.14∆ >1.86∆ >1.72∆ 0.41 1.10 0.97 2.41 1.10

Carbon Black Royaltherm 1411 100 phr >380∆ >640∆ >620∆ >480∆ >610∆ 110 210 210 350 >250∆

N-330 30 phr >2.62∆ >4.41∆ >4.27∆ >3.31∆ >4.21∆ 0.76 1.45 1.45 2.41 >1.72∆

Silica Royaltherm 1411 100 phr 580 >720∆ >720∆ >470∆ >540∆ 90 210 240 860 290VN-3 silica 45 phr 4.00 >4.97∆ >4.97∆ >3.24∆ >3.72∆ 0.62 1.45 1.66 5.93 2.00

Plasticizer Royaltherm 1411 100 phr >260∆ >280∆ >260∆ >270∆ >250∆ 30 70 70 >350∆ 80Dioctyl Phthalate 12 phr >1.79∆ >1.93∆ >1.79∆ >1.86∆ >1.72∆ 0.21 0.48 0.48 >2.41∆ 0.55

Antistatic Royaltherm 1411 100 phr >230∆ >290∆ >160∆ 200 >250∆ 40 90 90 350 120Armostat 550 5 phr >1.59∆ >2.00∆ >1.10∆ 1.38 >1.72∆ 0.28 0.62 0.62 2.41 0.83


Silicone Rubber (MQ, VMQ, PMQ, PVMQ)

thermoset rubber

Trade Names Manufacturer• Blensil G.E. Silicones• Elastosil Wacker Chemical Corp.• Silastic Dow Corning STI

General DescriptionSilicone rubber is characterized by an inorganic poly-meric backbone made up of silicon to oxygen bondswhich are known as siloxane linkages. The majority ofsilicon atoms in the silicone polymer backbone havetwo pendant methyl groups, which forms the mostcommon silicone polymer used in silicone rubbers,polydimethyl siloxane (MQ). By replacing a portion ofthe methyl groups with other species, the silicone rub-ber can be given crosslink sites or properties tailoredfor specific needs. For example, in peroxide cured sili-cone rubber systems, a small percentage of the methylgroups are replaced with vinyl groups (VMQ). Thevinyl group containing polymers is also used in con-junction with a platinum catalyst and suitable hydridecrosslinkers to produce addition cure silicone formula-tions. In RTV silicone adhesives and condensationcure compounds, hydrolyzable groups are capped ontothe terminal ends of the silicone polymer to providesites for crosslinking to occur when moisture reactswith these sites to leave reactive silanol sites. As wasmentioned, replacing a portion of the methyl groupswith other species can also provide properties for spe-cific needs. For example, replacing 5-10% of themethyl groups with bulkier phenyl groups will dramati-cally drop the brittle point of the silicone (PMQ).Replacing a portion of the methyl groups with trifluoro-propyl groups will increase the polarity of the siliconerubber, thus improving its resistance to non-polar sol-vents. These types of silicones are known as fluorosili-cone elastomers and are discussed in a separate chapter.

General PropertiesThe unique properties of polydimethyl siloxane elas-tomers arise primarily from the high bond energy ofthe silicon oxygen bonds along the backbone, andfrom the non-polar nature of the two methyl groupswhich are pendant from each of the silicon atoms. Theresult is an elastomer with good flexibility and com-pression set resistance over a wide temperature range.The silicone oxygen bond results in a polymer withexcellent resistance to UV and ozone, as well as long-term exposure to temperatures of 400oF (204oC) andintermittent exposure to temperatures as high as 600oF(316oC). More importantly, silicone elastomers retain

54

much of their tensile strength and compression setresistance at these high temperatures. The large vol-ume of the silicon atom also results in a polymer with alarge amount of free space and flexibility.Consequently, silicone polymers have high gas perme-ation rates and remain flexible to temperatures as lowas -60oF(-51oC). With the addition of phenyl groups on thebackbone, the brittle point can be lowered to -120oF (-84oC). The lack of polarity in the silicone elastomerresults in very good resistance to polar solvents suchas water and alcohols. Non-polar solvents such asaliphatic and aromatic hydrocarbons tend to swell sili-cones 200-300% and often require the use of the morepolar fluorosilicone elastomers. Resistance to manyacids and salts is good, though strong bases willdegrade the polymer.

Typical Applications• Automotive Hoses, gaskets, seals, ignition

cable insulation

• Industrial Adhesives, oven door gaskets, seals, sponges

• Medical Implantable devices, tubing


• Medium Surface Insensitive CA - Prism 401Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Light Curing Acrylic - Loctite 3105

• Low Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives All Except Plasticizer - Increase CA



Silicone Rubber SE 456U by General Electric








(MPa)

Cure and ReinforcementSystem Used in AllFormulations

DiCumyl Peroxide 1.50 phrAerosil 200 5.00 phr

Control: SE 456U 100 phr <10 70 220 <10 10 290 200 <10 230 60<0.07 0.48 1.52 <0.07 0.07 2.00 1.38 <0.07 1.59 0.41


uide for Bonding R

ubbers and TPEs

55

T80 Cure SE 456U 100 phr 20 190 290 <10 30 180 280 20 230 60Cured to 80% of Modulus at Full Cure 0.14 1.31 2.00 <0.07 0.21 1.24 1.93 0.14 1.59 0.41

Carbon Black SE 456U 100 phr <10 >250∆ >320∆ 10 80 190 200 <10 140 60N-550 30 phr <0.07 >1.72∆ >2.21∆ 0.07 0.55 1.31 1.38 <0.07 0.97 0.41

Calcium Carbonate SE 456U 100 phr <10 190 >310 40 60 200 200 40 >290∆ 60Calcium Carbonate 30 phr <0.07 1.31 >2.14∆ 0.28 0.41 1.38 1.38 0.28 >2.00∆ 0.41

Clay SE 456U 100 phr 80 >300∆ >320∆ 70 90 290 170 <10 140 60Polyethylene Glycol 3 phr, Whitex Clay 30 phr 0.55 >2.07∆ >2.21∆ 0.48 0.62 2.00 1.17 <0.07 0.97 0.41

Fumed Silica SE 456U 100 phr <10 110 350 <10 190 190 200 <10 250 60Aerosil 200 11.5 phr <0.07 0.76 2.41 <0.07 1.31 1.31 1.38 <0.07 1.72 0.41

Ground Silica SE 456U 100 phr <10 130 290 <10 30 200 200 <10 230 60Min-U-Sil 10 30 phr <0.07 0.90 2.00 <0.07 0.21 1.38 1.38 <0.07 1.59 0.41

Iron Oxide SE 456U 100 phr <10 110 >390∆ <10 80 180 200 <10 230 60Red Iron Oxide E-4182 30 phr <0.07 0.76 >2.69∆ <0.07 0.55 1.24 1.38 <0.07 1.59 0.41

Silicone Plasticizer SE 456U 100 phr <10 70 220 <10 10 290 170 <10 60 401000 cP fluid 15 phr <0.07 0.48 1.52 <0.07 0.07 2.00 1.17 <0.07 0.41 0.28

Antistatic SE 456U 100 phr 170 210 190 170 170 210 200 <10 230 60Armostat 550 4 phr 1.17 1.45 1.31 1.17 1.17 1.45 1.38 <0.07 1.59 0.41


Styrene-Butadiene Rubber (SBR)

thermoset rubber

Trade Names Manufacturer• Afpol Cal Polymers• Buna Bayer• Copeflex Coperbo• Duradene Firestone• Europrene Enichem• Kraton Shell Chemical• Plioflex Goodyear• Pliolite Goodyear• Solprene Housmex• Stereon Firestone

General DescriptionSBR is formed via the copolymerization of styrene andbutadiene. This can be performed as an emulsion orsolution polymerization. In emulsion polymerizations,the monomer is emulsified in a medium, such as water,using an emulsifying agent, such as soap. This can beperformed as a hot process at 122oF (50oC) or a coldprocess at 41-50oF (5-10oC). Solution polymerizationstypically occur in a hydrocarbon solution with an alkyllithium catalyst. Solution polymerizations offerimproved properties due to the increased control ofmolecular weight and stereospecificity. In addition,emulsion SBR typically contains 4-7% of non-rubberemulsifier residues which solution SBR does not.

General PropertiesApproximately 75% of the SBR produced in the US isused in tires. This is due to the superior abrasionresistance and traction of SBR. For tire applications,the glass transition temperature (Tg) is critical. If theTg is too high, the tires will become brittle in cold con-ditions. If the Tg is too low, the tire traction is compro-mised. Consequently, any rubber with a Tg which is notbetween -58 and -94oF (-50 and -70oC) must bemixed with at least one other rubber for tire applica-tions. NR and SBR have Tgs which allow them to beused as the sole elastomer in a tire compound. Theprocessing temperature of SBR has a large effect onthe resulting properties of the material. Cold SBR hasbetter abrasion resistance and dynamic properties, aswell as a higher capacity to be extended, than hot SBR.Therefore, hot SBR is no longer used for tire applica-tions. Due to the increased control of solution SBR,improved abrasion resistance, traction and hystereticproperties have been realized. Consequently, solutionSBR is rapidly replacing emulsion SBR for tire produc-tion. The addition of carbon black has many advanta-

56

geous effects on the properties of SBR. In particular, itincreases the strength properties, hardness and dimen-sional stability of SBR. In addition, it can provide electri-cal and thermal conductivity, all while lowering cost.

Typical Applications• Automotive Tires, hoses, belts

• Industrial Foamed products, extruded goods

• Consumer Shoe soles, waterproof materials

• Miscellaneous Adhesives, asphalt



• Medium Oxime Silicone - Ultra Black 5900Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105

• Low Acetoxy Silicone - Superflex 595Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives High Styrene - Increase

Carbon Black - IncreaseClay - IncreaseSilica - IncreaseStyrene Resin - IncreaseAromatic Oil - DecreaseProcessing Aid - IncreaseAntioxidant - Increase



Styrene Butadiene Rubber Plioflex by Goodyear








(MPa)

Cure System andReinforcement Usedin All FormulationsStearic Acid 1.00 phrZinc Oxide 5.00 phrSulfur 2.50 phrMBTS 1.50 phrTMTD 0.10 phrCarbon Black FEF N-550 10.00 phr

Control: Plioflex 1502 100 phr >220∆ >260∆ >260∆ >180∆ >190∆ 60 60 60 110 60Cold Emulsion Polymer, 23.5% Styrene >1.52∆ >1.79∆ >1.79∆ >1.24∆ >1.31∆ 0.41 0.41 0.41 0.76 0.41


uide for Bonding R

ubber and TPEs

57

T80 Cure Plioflex 1502 100 phr >220∆ >260∆ >260∆ >180∆ >110∆ 60 100 40 110 60Cured to 80% of Modulus at Full Cure >1.52∆ >1.79∆ >1.79∆ >1.24∆ >0.76∆ 0.41 0.69 0.28 0.76 0.41Cold Solution Polymer Firestone SBR 710 100 phr >220∆ >260∆ >260∆ >180∆ >110∆ 50 100 60 70 40

>1.52∆ >1.79∆ >1.79∆ >1.24∆ >0.76∆ 0.34 0.69 0.41 0.48 0.28

High Styrene Content Plioflex 1513 100 phr >310∆ >340∆ >260∆ >270∆ >290∆ 60 90 130 110 70Cold Emulsion Polymer, 40% Styrene >2.14∆ >2.34∆ >1.79∆ >1.86∆ >2.00∆ 0.41 0.62 0.90 0.76 0.48

Carbon Black Plioflex 1502 100 phr >550∆ >560∆ >530∆ >360∆ >350∆ 60 140 110 110 70FEF N-550 15 phr >3.79∆ >3.86∆ >3.65∆ >2.48∆ >2.41∆ 0.41 0.97 0.76 0.76 0.48

Calcium Carbonate Plioflex 1502 100 phr >220∆ >260∆ >260∆ >180∆ >190∆ 80 140 140 110 90Calcium Carbonate 60 phr >1.52∆ >1.79∆ >1.79∆ >1.24∆ >1.31∆ 0.55 0.97 0.97 0.76 0.62

Clay Plioflex 1502 100 phr >410∆ >460∆ >390∆ 270 270 60 150 170 210 130Dixie Clay 60 phr >2.83∆ >3.17∆ >2.69∆ 1.86 1.86 0.41 1.03 1.17 1.45 0.90

Silica Plioflex 1502 100 phr 460 >510∆ >570∆ 300 >330∆ 80 130 60 110 80Hi Sil 233 15 phr 3.17 >3.52∆ >3.93∆ 2.07 >2.28∆ 0.55 0.90 0.41 0.76 0.55

Styrene Resin Plioflex 1502 100 phr >460∆ >510∆ >490∆ 370 450 90 170 130 180 110Resin S6B 25 phr >3.17∆ >3.52∆ >3.38∆ 2.55 3.10 0.62 1.17 0.90 1.24 0.76

Aromatic Oil Plioflex 1502 100 phr >160∆ >170∆ >180∆ >180∆ >190∆ 40 60 60 110 40Aromatic Oil 37.5 phr >1.10∆ >1.17∆ >1.24∆ >1.24∆ >1.31∆ 0.28 0.41 0.41 0.76 0.28

Processing Aid Plioflex 1502 100 phr >220∆ >310∆ >260∆ >180∆ >240∆ 60 90 80 110 60Struktol WB212 4 phr >1.52∆ >2.14∆ >1.79∆ >1.24∆ >1.65∆ 0.41 0.62 0.55 0.76 0.41

Antioxidant Plioflex 1502 100 phr >220∆ >260∆ >260∆ >250∆ >250∆ 60 90 80 110 70DMQ 3 phr >1.52∆ >1.79∆ >1.79∆ >1.72∆ >1.72∆ 0.41 0.62 0.55 0.76 0.48

Antistatic Plioflex 1502 100 phr >220∆ >260∆ >260∆ >180∆ >270∆ 60 120 60 110 50Armostat 550 5 phr >1.52∆ >1.79∆ >1.79∆ >1.24∆ >1.86∆ 0.41 083 0.41 0.76 0.34


Styrenic TPEs (S-B-S, S-I-S, S-EB-S)


Trade Names Manufacturer• C-Flex Concept• Coperflex Coperbo• Dynaflex GLS Corp.• Europrene SOL EniChem• K-Resin Phillips• Kraton Shell Chemical Co.• Rimflex Synthetic Rubber Tech.• Solprene Housmex

General DescriptionStyrenic TPEs are block copolymers of styrene and adiene. In block copolymers, there are two distinctphases present. Each phase is composed of repeatingsegments of the same molecule. The simplestarrangement being A-B-A or a three-block structure.The dienes most commonly used are butadiene (S-B-S), isoprene (S-I-S) and ethylene-cobutylene (S-EB-S),an olefinic pair. The A indicates the hard copolymerblocks, and the B indicates the soft blocks. A blockcopolymer with an A-B or B-A-B backbone would nothave the desired properties of a TPE because the endsof the elastomeric regions would not be anchored incrystalline regions of the TPE.

General PropertiesStyrenic TPEs are typically the lowest cost TPEs butalso have the lowest performance. Specific gravitiesrange from 0.9 to 1.1, hardnesses range from 33 ShoreA to 55 Shore D, and ultimate tensile strengths rangefrom 500 to 4000 psi (3.5 to 27.6 MPa). Due to the non-polar nature of the backbone, styrenic TPEs can beextended with hydrocarbon-based oils and have excel-lent chemical resistance to polar solvents such asaqueous solutions, acetones and alcohols. However,this results in poor resistance to such non-polar sol-vents as oils, fuel and hydrocarbon solvents. As thestyrene content is increased, the TPE changes from aweak, soft material to a strong elastomer and then willeventually become leathery. At styrene contents above75%, they are hard, clear, glass-like products which areused as impact resistant polystyrene. Increasing thestyrene content hardens the polymer, while the addi-tion of extending oil softens the polymer. Bothincrease its processability. The weathering resistanceof styrenic rubbers is dictated by the soft elastomersegment. S-B-S and S-I-S structures have a doublebond per original monomer unit in the backbone. Thisunsaturatation limits their thermal, chemical andweathering resistance. Alternatively, S-EB-S has a

58

completely aliphatic backbone resulting in its superiorweatherability. Compounds based on S-EB-S normallycontain polypropylene which increases the solvent resis-tance, service temperature and processability. Useful ser-vice temperatures are low for styrenic TPEs ranging from-70 to 200oF (-57 to 93oC).

Typical Applications• Automotive Hoses, tubing

• Consumer Footwear soles

• Electrical Insulation and jackets for wire andcable

• Miscellaneous Sealants, coatings, caulkingadhesives, modified thermoplastics



• Medium Methyl CA -Super Bonder 496Rubber Toughened CA - Prism 480Rubber Toughened CA - Prism 4204



Silica - IncreaseWhiting - DecreaseAromatic Oil - DecreaseNaphthenic Oil - DecreasePlasticizer - DecreaseEVA Blend - DecreasePE Blend - IncreaseAntistat - DecreaseC-Flex - Decrease



PS Blend Kraton D 1101 100 phr 530 510 630 450 520 90 250 290 1020 480Polystyrene 100 phr 3.65 3.52 4.34 3.10 3.59 0.62 1.72 2.00 7.03 3.31

Cure System Usedin All FormulationsNone Required

Control: Kraton G 1650 100 phr 290 >510∆ 370 230 230 90 170 170 660 180S-EB-S 2.00 >3.52∆ 2.55 1.59 1.59 0.62 1.17 1.17 4.55 1.24


uide for Bonding R

ubber and TPEs

59

Carbon Black Kraton G 1650 100 phr 530 >810∆ 570 360 620 50 170 280 660 270N-550 100 phr 3.65 >5.59∆ 3.93 2.48 4.27 0.34 1.17 1.93 4.55 1.86

Clay Kraton G 1650 100 phr 220 510 580 320 340 50 170 230 >1090∆ 220Dixie Clay 100 phr 1.52 3.52 4.00 2.21 2.34 0.34 1.17 1.59 >7.52∆ 1.52

Silica Kraton G 1650 100 phr 440 >550∆ >550∆ 390 510 30 60 390 >660∆ 350Hi Sil 233 50 phr 3.03 >3.52∆ >3.79∆ 2.69 3.52 0.21 0.41 2.69 >4.55∆ 2.41

Whiting Kraton G 1650 100 phr 50 180 >200∆ 40 40 30 30 30 180 70Precipitated Whiting 100 phr 0.34 1.24 >1.35∆ 0.28 0.28 0.21 0.21 0.21 1.24 0.48

Aromatic Oil Kraton G 1650 100 phr 140 >300∆ 150 150 140 20 50 40 160 80Aromatic Oil 100 phr 0.97 >2.07∆ 1.03 1.03 0.97 0.14 0.34 0.28 1.10 0.55

Naphthenic Oil Kraton G 1650 100 phr 80 300 >370∆ 90 80 <10 50 40 170 60Naphthenic Oil 100 phr 0.55 2.07 >2.55∆ 0.62 0.55 <0.07 0.34 0.28 1.17 0.41

Plasticizer Kraton G 1650 100 phr 10 <10 20 10 20 <10 <10 <10 20 10Dioctyl Phthalate 50 phr 0.07 <0.07 0.14 0.07 0.14 <0.07 <0.07 <0.07 0.14 0.07

Processing Aid Kraton G 1650 100 phr 290 510 370 390 230 90 110 210 410 180Carnauba Wax 10 phr 2.00 3.52 2.55 2.69 1.59 0.622 0.76 1.45 2.83 1.24

EVA Blend Kraton G 1650 100 phr 130 240 370 180 140 20 40 170 410 220EVA 20 phr 0.90 1.65 2.55 1.24 0.97 0.14 0.28 1.17 2.83 1.52

PE Blend Kraton G 1650 100 phr 520 510 550 370 550 60 80 350 660 310Polyethylene 100 phr 3.59 3.52 3.79 2.55 3.79 0.41 0.55 2.41 4.55 2.14

Antistatic Kraton G 1650 100 phr 220 190 160 230 230 <10 100 120 260 50Armostat 550 5 phr 1.52 1.31 1.10 1.59 1.59 <0.07 0.69 0.83 1.79 0.34

Kraton D 1101 100 phr 160 280 370 230 230 50 170 130 >430∆ 180S-B-S Linear 1.10 1.93 2.55 1.59 1.59 0.34 1.17 0.90 >2.96∆ 1.24

C-Flex 100 phr 140 >240∆ 220 80 100 10 20 30 170 40Silicone Oil 0.97 >1.65∆ 1.52 0.55 0.69 0.07 0.14 0.21 1.17 0.28

Kraton D 1118X 100 phr 120 130 150 120 140 70 170 90 320 130SB Type Branched 0.83 0.90 1.03 0.83 0.97 0.48 1.17 0.62 2.21 0.90


(MPa)

Styrene Butadiene TPE Kraton by Shell Chemical and C-Flex by Concept Polymer Technology








Thermoplastic Vulcanizates (TPV)


Trade Names Manufacturer• Geolast Advanced Elastomer Systems• Santoprene Advanced Elastomer Systems

General DescriptionThermoplastic vulcanizates are elastomeric alloys of acontinuous plastic phase and a fine dispersion ofdynamically vulcanized rubber. Santoprene, for exam-ple, uses polypropylene as the plastic phase withEPDM as the rubber phase. Geolast also usespolypropylene for the plastic phase, however, nitrilerubber is used for the thermoset rubber phase.Generally, these compounds derive their physical prop-erties from the interaction of the two phases and donot use the fillers and extenders commonly used withmost thermoset rubber systems. Consequently, materi-al properties are primarily a function of the type andlevel of vulcanizate and its degree of crosslinking.Even though TPVs contain a vulcanizate phase, thesematerials can still be processed by common thermo-plastic processing equipment such as extrusion, injec-tion molding, blow molding, thermoforming and calen-dering.

General PropertiesIn general, TPVs offer the performance properties of athermoset rubber with the processing ease of a ther-moplastic. These properties include good tensilestrength, good abrasion resistance and outstandingfatigue flex resistance. The saturated nature of theolefinic backbone in the Santoprene and Geolast plas-tic phases, coupled with the highly crosslinked natureof their vulcanizate phases, gives them excellent chem-ical resistance, as well as good thermal and weather-ing resistance. Santoprene has shown good propertyretention after long-term exposure to acids, bases, andaqueous solutions. Resistance to oils and other hydro-carbons varies with grade and fluid type. However, thehigher the polarity of the fluid, the more likely it is toattack Santoprene. For increased oil resistance,Geolast offers superior performance because it utilizesnitrile as the vulcanizate phase rather than EPDM.Unlike most TPEs, which soften at high temperatures,TPVs have shown good property retention at tempera-tures as high as 275oF (135oC) and good compressionset resistance at temperatures as high as 212oF(100oC). Their low temperature performance is alsogood with brittle points below -67oF (-55oC).

60

Typical Applications• Automotive Air ducts, rack and pinion steering

boots, motor drive belts

• Construction Glazing seals, expansion joints

• Electrical Specialty wire and cable insulation

• Medical Drug vial stoppers, grommets, syringe plunger tips, volumetric infusion pump tips

• Miscellaneous Sander grips, squeegees, dust seals, clothes washer filter seals


• Medium Surface Insensitive CA - Prism 401Rubber Toughened CA - Prism 4204Two-Part No-Mix Acrylic - Depend 330Light Curing Acrylic - Loctite 3105

• Low Methyl CA - Super Bonder 496Rubber Toughened CA - Prism 480Acetoxy Silicone - Superflex 595Oxime Silicone - Ultra Black 5900Polyurethane - Loctite 3951

Effects of Formulation and Processing• Additives Grey Concentrate - Increase





Thermoplastic Vulcanizates Santoprene and Geolast by Advanced Elastomer Systems





(MPa)

Santoprene 101-55 Santoprene 101-55 100 phr 30 80 220 20 20 20 60 50 120 800.21 0.55 1.52 0.14 0.14 0.14 0.41 0.34 0.83 0.55The Loctite D

esign Guide for B

onding Rubbers and TP

Es61

Santoprene 101-73 Santoprene 101-73 100 phr <10 170 >390∆ 90 140 20 60 110 210 90<0.07 1.17 >2.69∆ 0.62 0.97 0.14 0.41 0.76 1.45 0.62

Santoprene 103-50 Santoprene 103-50 100 phr <10 180 1220 <10 <10 10 30 230 610 <10<0.07 1.24 8.41 <0.07 <0.07 <0.07 0.21 1.59 4.21 <0.07

Santoprene 201-55 Santoprene 201-55 100 phr 30 70 210 <10 30 <10 <10 50 180 <10100 phr 0.21 0.48 1.45 <0.07 0.21 <0.07 <0.07 0.34 1.24 <0.07

Santoprene 201-55 Santoprene 201-55 100 phr 30 140 >200∆ <10 30 20 60 70 180 80w/Grey Concentrate Grey Concentrate 4 phr 0.21 0.97 >1.38∆ <0.07 0.21 0.14 0.41 0.48 1.24 0.55

Santoprene 201-73 Santoprene 201-73 100 phr 90 230 >390∆ 230 240 10 10 10 280 1200.62 1.59 >2.69∆ 1.59 1.66 0.07 0.07 0.07 1.93 0.83

Santoprene 201-73 Santoprene 201-73 100 phr <10 320 330 230 50 10 10 100 280 120w/Grey Concentrate Grey Concentrate 4 phr <0.07 2.21 2.28 1.59 0.34 0.07 0.07 0.69 1.93 0.83

Santoprene 203-50 Santoprene 203-50 100 phr <10 320 1020 <10 <10 <10 40 <10 310 <10<0.07 2.21 7.03 <0.07 <0.07 <0.07 0.28 <0.07 2.14 <0.07

Santoprene 203-50 Santoprene 203-50 100 phr <10 430 1070 <10 130 <10 50 170 800 60w/Grey Concentrate Grey Concentrate 4 phr <0.07 2.97 7.38 <0.07 0.90 <0.07 0.34 1.17 5.52 0.41

Geolast 701-70W183 Geolast 701-70W183 100 phr 230 250 >250∆ 150 >270∆ 60 70 120 280 1501.59 1.72 >1.72∆ 1.03 >1.86∆ 0.41 0.48 0.83 1.93 1.03

Geolast 701-80W183 Geolast 701-80W183 100 phr 320 360 >350∆ 320 400 30 70 180 320 1202.21 2.48 >2.41∆ 2.21 2.76 0.21 0.48 01.24 2.21 0.83

Cure System Usedin All InformationNone Required

Geolast 701-87W183 Geolast 701-87W183 100 phr 430 380 360 >240∆ 270 <10 <10 40 750 1802.97 2.62 2.48 >1.66∆ 1.86 <0.07 <0.07 0.28 5.17 1.24

Geolast 703-4045 Geolast 703-45 100 phr 420 390 470 430 550 <10 <10 230 250 <102.90 2.69 3.24 2.97 3.79 <0.07 <0.07 1.59 1.72 <0.07

Test MethodologyDetermining The Experimental Matrix

The Selection of Adhesives

It was desired to evaluate a cross section of theadhesives which were believed to be best suited forbonding elastomers. The adhesive families selectedwere cyanoacrylates, acrylics, polyurethanes andsilicones. The cyanoacrylate family was further bro-ken down into the following five subcategories:methyl; surface insensitive ethyl; rubber toughenedethyl; rubber toughened, surface insensitive, ther-mally resistant ethyl; and surface insensitive ethylused in conjunction with a surface primer. Theacrylic family was also broken down into subcate-gories, namely two-part no-mix and light curingacrylic adhesives. Finally, both acetoxy and oximesilicones were evaluated. From each specific adhe-sive type, an adhesive was then selected which wasbelieved to be best representative of the perfor-mance of that adhesive type when bonding elas-tomers. The adhesives which were selected aretabulated below:

Adhesive Adhesive Description • Super Bonder 496 Methyl cyanoacrylate• Prism 401 Surface insensitive ethyl

cyanoacrylate• Prism 401 and Surface insensitive ethyl

Prism Primer 770 cyanoacrylate used inconjunction with a chemical surface primer

• Prism 480 Rubber toughened ethyl cyanoacrylate

• Prism 4204 Clear, rubber toughened,surface insensitive, thermally resistant cyanoacrylate

• Superflex 595 Acetoxy silicone• Ultra Black 5900 Oxime silicone• Depend 330 Two-part no-mix acrylic • Loctite 3105 Light curing acrylic • Loctite 3951and Polyurethane used in conjuc-

Primer 7251 tion with a chemical surface primer

The Selection of Elastomers

The various types of elastomers which are currentlyavailable were surveyed, and twenty-five of themost commonly used elastomers were selected fortesting. The specific formulations of these elas-tomers which were evaluated were chosen in one ofthe two following ways:

Specialty Formulations

1. A grade of the elastomer which had no fillers or additives was selected and tested for bond strength performance with the aforementioned adhesives. This was the control which was used to determine the effect of additives, fillers and processing changes on the bondability of an elastomer.

2. The most common additives and fillers used witheach elastomer were identified. Variations in polymer structure which differentiate different grades of the elastomer were also identified. Forexample, acrylonitrile level in nitrile rubber or vinyl acetate level in ethylene-vinyl acetate copolymer.

3. A separate formulation of the elastomer was compounded which represented a high level of additive or filler, a processing change or avariation in the polymer structure.

4. Adhesive bond strength evaluationswere performed.

5. The results were analyzed to determine if the filler, additive or change in polymer structure resulted in a statistically significant change in the bondability of the elastomer in comparison with the unfilled control within 95% confidence limits.

Commercially Available Grades

For five elastomers, commercially available gradeswere selected to represent a cross section of thevarious grades which were available and tested forbond strength.

Determining The Test Method

The lap shear test method (ASTM D1002) is typicallyused to determine adhesive shear strengths.However, because it was designed for use withmetals, it has several serious limitations when eval-uating elastomers. For example, because elas-tomers have much lower tensile strength than met-als, the lap shear specimens are much more likelyto experience substrate failure than the metal lapshear specimens. This makes the comparativeanalysis of different adhesives on an elastomer verydifficult, since many of the adhesives will achievesubstrate failure, rendering it impossible to make

The Loctite Design Guide for Bonding Rubbers and TPEs62

performance comparisons. Another major disad-vantage to using the lap shear test method is thatelastomers will deform more readily than metal as aresult of their lower moduli. This results in severepart deformation which introduces peel and cleav-age forces on the joint. While this cannot be avoid-ed while testing elastomers, especially under highloads, providing a rigid support for the rubber canminimize this effect. For this testing, the rubbersamples were bonded to steel lap shears to providethis rigid support.

Proper selection of the joint overlap can also givebond strength results which more accurately reflectthe adhesive bond strength. When testing flexiblematerials in a lap joint, it is desirable to minimizethe overlap to produce as uniform a stress distribu-tion as possible over the bond area. Due to theflexibility of elastomeric materials, stresses on a lapjoint are concentrated on the leading edge of thebonded assembly. As a result, when the overlaplength is increased, the measured bond strengthappears to drop. This occurs because the area ofthe joint increases, but the force that the joint canwithstand does not increase proportionately, since itis still concentrated on the leading edges of thejoint. Through experimentation, it was found thatdecreasing the overlap below 0.25” did not signifi-cantly increase the measured bond strength. As aresult, it was concluded that the stress distributionover this bond area was sufficiently uniform to usefor comparative testing.

The flexibility and low tensile strength inherent inelastomeric materials make it difficult to design atest specimen which will omit peel forces and notexperience substrate failure at low loadings. This isparticularly difficult when the test specimen mustbe compatible with a large-scale test program, thatis, it must be amenable to consistent assembly inlarge numbers. The test assembly which wasselected to address these concerns in this test pro-gram is shown below in Figure 1.

Limitations

While the bond strengths in this guide give a goodindication of the typical strengths that can beachieved with many elastomers, as well as theeffect of many fillers and additives, they also faceseveral limitations. For example, the additives andfillers were selected because they were believed tobe representative of the most commonly used addi-tives and fillers. There are, however, many types ofeach additive and filler produced by many differentcompanies, as well as different types of the sameadditives and/or fillers. These additives and fillersmay not influence the bondability of an elastomerconsistently. In addition, the additives and fillerswere tested individually in this guide. Consequently,the effect of interactions between these differentfillers and additives on the bondability of materialscould not be determined.

Another consideration that must be kept in mindwhen using this data to select an adhesive/elas-tomer combination is how well the test method willreflect the stresses that an adhesively bonded jointwill see in “real world” applications. Adhesivelybonded joints are designed to maximize tensile andcompressive stresses and to minimize peel andcleavage stresses. The optimum adhesive joint willhave a much larger magnitude of the former twostresses than of the latter two. Thus, the shearstrength of an adhesive is generally most critical toadhesive joint performance. However, since alladhesive joints will experience peel and cleavagestresses to some degree, their effects should not bedisregarded.

Finally, selecting the best adhesive for a givenapplication involves more than selecting the adhe-sive which provides the highest bond strength.Other factors such as speed of cure, environmentalresistance, thermal resistance, suitability forautomation and price will play a large role in deter-mining the optimum adhesive system for a givenapplication. It is suggested that the reader refer tothe chapters which explain the properties of thevarious adhesives in greater detail before choosingthe best adhesive for an application.

Although there are some limitations to the degreethe information provided in this guide can beextrapolated, the data contained here should beinvaluable in helping the end user quickly makeadhesive selections based on the adhesive perfor-mance on various adhesive/elastomer combinations.


Figure 1 Rubber Bonding Test Specimen

1/4” overlap

1”x4”x1/16” steel lapshear specimen

1”x1”x1/8” rubber specimens

Once the most promising combinations of adhe-sives and elastomers have been identified, it isimportant that testing be performed on assembliesto insure that they will meet or exceed all perfor-mance requirements.

Test Methods

Substrate Preparation

1. Substrates were cut into 1” by 1” by 0.125”test specimens.

2. All bonding surfaces were cleaned withisopropyl alcohol.

Adhesive Application and Cure Method

Cyanoacrylates (Super Bonder 496, Prism 401, Prism480 and Prism 4204)

1. Adhesive was applied in an even film to one testspecimen.

2. A second test specimen was mated to the first with a 0.25” overlap (bond area = 0.25 in2).

3. A fixturing weight was placed over the modified lap shear test specimen.

4. The mated assembly was allowed to cure at ambient conditions for 1 week before testing.

Cyanoacrylates with Polyolefin Primers (Prism 401and Prism Primer 770)

1. Polyolefin primer was brushed onto each bond-ing surface.

2. The polyolefin primer’s carrier solvent was allowed to flash off.

3. Adhesive was applied in an even film to one substrate.

4. The second test specimen was mated to the first with a 0.25” overlap (bond area = 0.25 in2).



Two-Part No-Mix Acrylic (Depend 330)

1. Activator 7387 was sprayed on one test speci-men.

2. The activator’s carrier solvent was allowed to flash off for more than two to five minutes.

3. Depend 330 was applied in an even film to a second test specimen.




Light Cure Acrylic (Loctite 3105)

1. Adhesive was applied in an even film to onetest specimen.

2. A UV transparent, medical polycarbonate 1” by 4” by 0.125” test specimen was cleaned with iso-propyl alcohol.


4. The assembly was irradiated (through thepolycarbonate) in an ultraviolet light source for 30 seconds to cure the adhesive. The ultraviolet light source used was a Fusion- UV Curing System, equipped with an H-bulb having an irradiance of approximately 100mW/cm2@365nm.

Silicones (Superflex 595 and Ultra Black 5900)

1. Adhesive was applied in an even film to one testspecimen.

2. A second test specimen was mated to the first with a 0.25” overlap (bond area = 0.25 in2).




Polyurethanes (Loctite 3951)

1. Primer 7251 was brushed onto each bonding surface.

2. The primer’s carrier solvent was allowed to flash off.

3. Adhesive was applied in an even film to one substrate.



6. The mated assembly was allowed to cure at ambient conditions for one week before testing.


Index of Trade Names and AcronymsTrade Name/Acronym Elastomer Type Manufacturer/Comment Page

ACM Polyacrylate Rubber Acronym for Elastomer 42Afpol Styrene-Butadiene Rubber Cal Polymers 56Alcryn Melt Processible Rubber DuPont 34Baypren Polychloroprene Bayer 38BIIR Halogenated Butyl Rubber Acronym for Elastomer 30Blensil Silicone General Electric Silicones 54Breon Nitrile Rubber B.P. Chemicals 40Buna Styrene-Butadiene Rubber Bayer 56Butaclor Polychloroprene Enichem Elastomers 38C-Flex Styrenic TPE Concept 58Chemigum Nitrile Rubber Goodyear 40CIIR Halogenated Butyl Rubber Acronym for Elastomer 30CO Epichlorohydrin Rubber Acronym for Elastomer 18Compo Crepe Natural Rubber International Type of NR 36Copeflex Styrene-Butadiene Rubber Coperbo 56Coperflex Styrenic TPE Coperbo 58CR Polychloroprene Acronym for Elastomer 38CSM Chlorosulfonated Polyethylene Acronym for Elastomer 14Dai-el Fluorocarbon Rubbers Daikin 26Duradene Styrene-Butadiene Rubber Firestone 56Dynaflex Styrenic TPE GLS Corporation 58Ecdel Copolyester TPE Eastman 16ECO Epichlorohydrin Rubber Acronym for Elastomer 18EEA Ethylene Acrylic Rubber Acronym for Elastomer 20Elastosil Silicone Wacker Chemical Corporation 54Elvax Etylene-Vinyl Acetate DuPont 24Engage Polyolefin DuPont Dow Elastomers 46EPDM Ethylene Propylene Rubber Acronym for Elastomer 22EPM Ethylene Propylene Rubber Acronym for Elastomer 22Epsyn Ethylene Propylene Rubber Copolymer Rubber Co. 22Escorene Etylene-Vinyl Acetate Exxon Chemical 24Estate Brown Crepe Natural Rubber International Type of NR 36Europrene SOL Styrenic TPE Enichem 58Europrene Styrene-Butadiene Rubber Enichem 56Europrene Polyacrylate Rubber Enichem Elastomers America 42EVA Ethylene Vinyl Acetate Acronym for Elastomer 24Evazote Ethylene Vinyl Acetate B.P. Chemicals 24Exxon Bromobutyl Halogenated Butyl Rubber Exxon Chemical 30Exxon Butyl Butyl Rubber Exxon Chemical 12Exxon Chlorobutyl Halogenated Butyl Rubber Exxon Chemical 30FE Fluorosilicone Rubber Shinetsu Chemical 28FKM Fluorocarbon Rubber Acronym for Elastomer 26Flat Bark Crepe Natural Rubber International Type of NR 36Fluorel Fluorocarbon Rubber 3M 26FSE Fluorosilicone Rubber General Electric 28FVMQ Fluorosilicone Rubber Acronym for Elastomer 28GCO Epichlorohydrin Rubber Acronym for Elastomer 18


Trade Name/Acronym Elastomer Type Manufacturer/Comment Page

GECO Epichlorohydrin Rubber Acronym for Elastomer 18Geolast Thermoplastic Vulcanizate Advanced Elastomer Systems 60GPO Poly(propylene oxide) Rubber Acronym for Elastomer 48Hercuprene Polyolefin J-Von 46H-NBR Hydrogenated Nitrile Rubber Acronym for Elastomer 32HSN Hydrogenated Nitrile Rubber Acronym for Elastomer 32Humex Nitrile Rubber Huels Mexicanos 40Hycar Polyacrylate Rubber B.F. Goodrich 42Hydrin Epichlorohydrin Rubber Zeon 18Hypalon Chlorosulfonated Polyethylene DuPont 14HyTemp Polyacrylate Rubber Zeon Chemical 42Hytrel Copolyester TPE DuPont 16IIR Butyl Rubber Acronym for Elastomer 12IR Polyisoprene Acronym for Elastomer 44Isolene Polyisoprene Hardman 44Kalrez Fluorocarbon Rubber DuPont 26Kraton Styrene-Butadiene Rubber Shell Chemical 56Kraton Styrenic TPE Shell Chemical 58K-Resin Styrenic TPE Phillips 58Krynac Nitrile Rubber Polysar International 40Lomod Copolyester TPE General Electric 16LP Polysulfide Rubber Morton Thiokol 50LS Fluorosilicone Rubbers Dow Corning 28MPR Melt Processible Rubber Acronym for Elastomer 34MQ Silicone Rubber Acronym for Elastomer 54Natsyn Polyisoprene Goodyear 44NBR Nitrile Rubber Acronym for Elastomer 40Neoprene Polychloroprene DuPont 38Nipol Polyisoprene Goldsmith & Eggleton 44Nipol Nitrile Rubber Nippon Zeon 40Nordel Ethylene Propylene Rubber DuPont 22NR Natural Rubber Acronym for Elastomer 36Nysen Nitrile Rubber Copolymer Rubber 40Pale Crepe Natural Rubber International Type of NR 36Parel Poly(propylene oxide) Rubber Zeon Chemical 48Perbunan Nitrile Rubber Mobay 40Plioflex Styrene-Butadiene Rubber Goodyear 56Pliolite Styrene-Butadiene Rubber Goodyear 56PMQ Silicone Rubber Acronym for Elastomer 54POE Polyolefin Acronym for Elastomer 46Polysar EPDM Ethylene Propylene Rubber Bayer 22Polysar Bromobutyl Halogenated Butyl Rubber Bayer 30Polysar Butyl Butyl Rubber Bayer 12Polysar Chlorobutyl Halogenated Butyl Rubber Bayer 30Pure Smoked Blanket Crepe Natural Rubber International Type of NR 36PVMQ Silicone Rubber Acronym for Elastomer 54Ribbed Smoked Sheet Natural Rubber International Type of NR 36Rimflex Styrenic TPE Synthetic Rubber Technologies 58


Trade Name/Acronym Elastomer Type Manufacturer/Comment Page

Riteflex Copolyester TPE Hoescht Celanese 16Royalene Ethylene Propylene Rubber Uniroyal Chemical 22Royaltherm Silicone-Modified EPDM Uniroyal Chemical 52Santoprene Thermoplastic Vulcanizate Advanced Elastomer Systems 60Sarlink Polyolefin DSM Thermoplastic 46SBR Styrene-Butadiene Rubber Acronym for Elastomer 56S-B-S Styrenic TPE Acronym for Elastomer 58S-EB-S Styrenic TPE Acronym for Elastomer 58Silastic Silicone Dow Corning STI 54S-I-S Styrenic TPE Acronym for Elastomer 58Ski-3 Polyisoprene Alcan 44Solprene Styrene-Butadiene Rubber Housmex 56Solprene Styrenic TPE Housmex 58Stereon Styrene-Butadiene Rubber Firestone 56Synthetic Natural Rubber Polyisoprene Common Name for IR 44Tecnoflon Fluorocarbon Rubber Ausimont 26Therban Hydrogenated Nitrile Rubber Bayer 32Thick Blanket Crepe Natural Rubber International Type of NR 36Thin Brown Crepe Natural Rubber International Type of NR 36Thiokol Polysulfide Rubber Morton Thiokol 50TPV Thermoplastic Vulcanizate Acronym for Elastomer 60Ultrathene Ethylene-Vinyl Acetate Quantum Chemicals 24Vamac Ethylene Acrylic Rubber DuPont 20Vistalon Ethylene Propylene Rubber Exxon Chemical 22Viton Fluorocarbon Rubbers DuPont 26VMQ Silicone Rubber Acronym for Elastomer 54XNBR Nitrile Rubber Acronym for Elastomer 40Zetpol Hydrogenated Nitrile Rubber Zeon Chemical 32


The trade names mentioned above are the property of the manufacturing companies listed.

Acknowledgements This design guide would not have been possible without theexpertise, advice and material samples graciously providedby the companies listed below. Loctite Corporation wouldlike to take this opportunity to thank them for their invalu-able assistance in developing this resource.

Advanced Elastomer SystemsWayne Buchheim Senior Marketing Technical Service Specialist

Akron Rubber Development Laboratory, Inc.Krishna C. Baranwal, Ph.D. Executive Vice President, TechnicalRobert MayManager Compound Development Mixing and ProcessingRobert SamplesChief Executive OfficerMalcolm WilbornVice President, Business Development Services

Bose CorporationRobert LituriCorporate Chemist

Florida State UniversityJoe DeforteMechanical Engineer

R. T. Vanderbilt CompanyJoseph DeMelloSales Representative


Disclaimer The information contained herein is intended to beused solely as an indicator of the bondability of theevaluated elastomers. The information is believedto be accurate, and is well suited for comparativeanalysis; however, the testing was performed usinga limited number of adhesive lots, elastomer lots,and replicates. Consequently, this makes the infor-mation contained herein inappropriate for specifica-tion purposes.

All polymeric materials have the potential forswelling or stress cracking when exposed touncured adhesive depending on the exposure time,part geometry, stresses, and composition variables.Consequently, it is important that the end user eval-uate the suitability of the adhesive in their processto insure that the adhesive does not detrimentallyaffect the performance of the plastic or elastomer.

Loctite cannot assume responsibility for the resultsobtained by others over whose methods we have nocontrol. It is the user's responsibility to determine

suitability for the user's purpose of any productionmethod mentioned herein and to adopt such pre-cautions as may be advisable for the protection ofproperty and of persons against any hazards thatmay be involved in the handling and use thereof.In light of the foregoing, Loctite Corporationspecifically disclaims all warranties of mer-chantability or fitness for a particular purposearising from sale or use of LoctiteCorporation's products. Loctite Corporationspecifically disclaims any liability for conse-quential or incidental damages of any kind,including lost profits. The discussion herein ofvarious process or compositions is not to be inter-preted as representation that they are free fromdomination of patents owned by others or as alicense under any Loctite Corporation patents whichmay cover such processes, or compositions. Werecommend that each prospective user test the pro-posed application in its manufacturing process,using this data as a guide. This product may becovered by one or more United States or foreignpatents or patent applications.


Superflex is a TM; and Ultra Black, Loctite, Black Max, PRISM, Super Bonderand Depend are Reg. TMs of Loctite Corp., Hartford, CT 06106 U.S.A.Fusion UV Curing Systems is a TM of Fusion Systems Corporation.

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