David Vroom Consultant
Development of Advanced Development of Advanced Development of Advanced Development of Advanced CrossCrossCrossCross----linking Materialslinking Materialslinking Materialslinking Materials
Scope of the PresentationScope of the PresentationScope of the PresentationScope of the Presentation
Materials designed for radiation processing• Cross-linking of Polymers – Industrial
applications- wire and cable insulation - elastic memory products- circuit protection devices - positive temperature coefficient (PTC)
heaters
Scope of the PresentationScope of the PresentationScope of the PresentationScope of the Presentation
• Industry oriented – non-academic- complex, proprietary formulations
• No trade secrets, formulations• Product oriented
- market pull• Emphasis on e-beam irradiated
materials
TodayTodayTodayToday’’’’s Split Markets Split Markets Split Markets Split Market
• High performance / high cost / niche- aerospace - defense- marine - ferries- medical- mass transit- energy generation / distribution- telecommunications – outside plant- circuit protection - telecommunications - industrial heating
TodayTodayTodayToday’’’’s Split Markets Split Markets Split Markets Split Market
• Required performance / low cost / pseudo commodity- automotive- commercial electronics- commercial general- circuit protection – batteries - non-industrial heating
TodayTodayTodayToday’’’’s markets markets markets market
• Green- bio-degradable- recyclable formulations- use of recycled materials
• RoHS- reduce / eliminate heavy metals- lead free (soldering)
TodayTodayTodayToday’’’’s markets markets markets market
• Higher operating / maximum temperatures
• Small dimensions• Light weight• More aggressive solvents• Extended life
TodayTodayTodayToday’’’’s Realitys Realitys Realitys Reality
• Reformulation- raw materials obsolescence
- edge materials- changing regulations- challenge all components availability
• Materials allocation- fluoropolymers
High Performance MaterialsHigh Performance MaterialsHigh Performance MaterialsHigh Performance Materials
• Higher cost acceptable• High quality• Meet or beat the spec.• Higher operating temperatures
- lead free soldering applications- engine compartments
High Performance MaterialsHigh Performance MaterialsHigh Performance MaterialsHigh Performance Materials
• Superior mechanical properties- defense applications
• Superior chemical properties- NBC (nuclear, biological, chemical)
• Acceptable manufacturability• Acceptable delivery – longer lead times• Generally lower volumes
Acceptable Performance Acceptable Performance Acceptable Performance Acceptable Performance MaterialsMaterialsMaterialsMaterials• Lowest possible cost or lower• High quality• Meet the spec.• Appropriate operating temperature• Appropriate mechanical properties• Appropriate chemical resistance
Acceptable Performance Acceptable Performance Acceptable Performance Acceptable Performance MaterialsMaterialsMaterialsMaterials• Environmentally acceptable
- RoHS, halogen free• Superior manufacturability• Superior delivery – off-the-shelf,
scheduled deliveries• Generally higher volumes
Materials CharacteristicsMaterials CharacteristicsMaterials CharacteristicsMaterials Characteristics
High performance and acceptable performance crosslink-able polymeric
materials are complex and require significant development.
Materials Development ProcessMaterials Development ProcessMaterials Development ProcessMaterials Development Process
• Needs / specification from customer• Product design – specification
refinement• Formulation – choose polymer(s),
modifier(s), additives – iterative process, pass the tests
• Compounding – scaling issues• Manufacturability
Choosing the right componentsChoosing the right componentsChoosing the right componentsChoosing the right components
• Market needs drive choice of components- low cost – polyolefin co-polymers- high temperature – fluoropolymers, - high expansion ratio – highly branched
polyolefins- oil resistance – fluoropolymers- chemical resistance – fluoropolymers,
fluoroelastomers, polyesters
Choosing the right componentsChoosing the right componentsChoosing the right componentsChoosing the right components
• Market needs drive the choice of components- abrasion resistance – fluoropolymers, - cut through resistance - nylons- lubricity – fluoropolymers- biocompatibility - flame retardants – brominated
compounds, red phosphorous, water releasing compounds (Mg(OH)2, Al2O3
Choosing the right componentsChoosing the right componentsChoosing the right componentsChoosing the right components
• Chemistry helps guide components choice- compatibility of components- cross-linking stabilization of quasi-
compatible components- material interaction with the
environment – substrate
Choosing the right componentsChoosing the right componentsChoosing the right componentsChoosing the right components
• Chemistry helps guide components choice- adhesive bond to jacket - substrate- crosslink / degradation dose matching
- multiple layer products- temperature matching – jacket,
adhesive- e-beam vs. Co-60 irradiation – dose
rate issues
Commonly Used PolymersCommonly Used PolymersCommonly Used PolymersCommonly Used Polymers
Little change over the past 25 years• Polyolefins
- polyethylene – HD, LD, LLD, VL, UL- co-polymers – EMA, EBA, EVA (modifiers)
• Fluoropolymers- ETFE, PVDF, PFA/MFA,
(PTFE)
Commonly Used PolymersCommonly Used PolymersCommonly Used PolymersCommonly Used Polymers
• Elastomers- EPDM, fluoroelastomers (modifiers)
• Polyesters – PBT, Hytrel• Nylons – 11, 12• Polyamides (adhesives)
Additives Additives Additives Additives
List of 35 types of additives• Antioxidants• Biocides• Blowing agents
- Physical blowing agents (compressed gases, volatile liquids)
- Chemical blowing agents (solid compounds that decompose to evolve gas)
AdditiveAdditiveAdditiveAdditive
• Conductive fillers – for PTC heaters, circuit protection devices, high voltage stress grading, EMI shielding, induction heating - carbon blacks- metal powders- ferromagnetic materials
AdditivesAdditivesAdditivesAdditives
• Cross-linking enhancers - radiation• Cross-linking inhibitors - radiation• Chemical curing agents (peroxides)• Degradability agents (to promote bio- or
photo- degradation)• Fiber (glass, graphite, metal, etc) for
reinforcing
AdditivesAdditivesAdditivesAdditives
• Flame retardants- Halogenated- Halogen free- Synergists
• Inert fillers (low cost)• Pigments• Recyclate additives (to boost properties
of recycled plastics)• UV stabilizers
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Meet the customer needs / specificationMarket drives choices - use temperature / maximum
temperature- flame retarded- low smoke- electrical properties- solvent resistance
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Meet the customer needs / specificationMarket drives choices - mechanical properties- installation methods / concerns- cost- weight- product size range
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Choose base polymer(s)- determines main features of material
- operating temperature range- gross mechanical and chemical properties
- effects of crystallinity – additives contained in amorphous regions only
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Choose base polymer(s)- average molecular weight
- crosslink-ability vs. melt process-ability
- molecular weight distribution- crosslink-ability vs. melt process-
ability
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Choose polymer modifiers- reduce crystallinity – important if high
additive levels required in highly crystalline materials like HD polyethylene
- increase flexibility- lower cost
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Choose polymer modifiers- compatibility of polymers and other
additives- quasi compatibility – use radiation to
lock components together - materials that are designed to absorb
and coat other materials- improve manufacturability –
processing speed, drool, clogs
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Additives- complex formulations – in excess of 10
components in some cases- high solids (non-melting) content – can
be over 50%- green anti-oxidant and flame
retardant packages - particle size – small tubing, conductive
polymers
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• Additives- green cross-linking promoters
- phasing out traditional types like tri-chlorobenzene (TCB)
- pigments – heavy metals, radiation bleaching / color change
- compatibility - bleeding
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
• One formulation may not pass all tests in product size range- cost- VW1 flame test – UL test- chemical resistance- titrate the formulation to fine tune- should look and feel the same
Formulation ConsiderationsFormulation ConsiderationsFormulation ConsiderationsFormulation Considerations
The effects of radiation on all components must be
understood
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsHigh Performance – Energy production /
distribution – splices / terminations• Needs
- high voltage insulation – up to 69KV- acceptable shrink time- cable type specific – oil filled / solid
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsHigh Performance – Energy production /
distribution, tubing / molded parts• Needs
- moisture proof- stress grading- no arc-tracking - charring- rodent / insect proof- minimal uv degradation (30 yr. life)
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsHigh Performance – Energy production /
distribution, tubing / molded parts• Solutions
- product design- thick wall product / shrink time / dual /
multi-layer wall thermoplastic / elastomer product
- Co-60 irradiation – thick / rigid
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsHigh Performance – Energy production /
distribution, tubing / molded parts• Solutions
- polyolefin or fluoropolymer holdout layer – EPDM inner layer
- conductive additives for stress grading
- additives to eliminate arc tracking –diatomaceous earth
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsAcceptable performance – Automotive
tubing / molded parts• Needs – a demanding market
- low cost- delivery, delivery, delivery – line down
considerations- high quality- cable systems protection - moisture
sealing
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsAcceptable performance – Automotive
tubing / molded parts• Needs
- chemical resistance – brake fluids, coolants, oils, fuel
- abrasion resistance- higher temperature jackets and
adhesives
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsAcceptable performance – Automotive
tubing / molded parts• Needs
- rapid, reliable, foolproof installation- color matching - beautification - generally green
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsAcceptable performance – Automotive
tubing / molded parts• Solutions
- single and dual wall requirements- polyolefin HDPE, LDPE /
fluoropolymers based outer jacket- adhesive / blocking material inner wall
- matched to jacket and substrate
Elastic Memory Elastic Memory Elastic Memory Elastic Memory –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials SolutionsAcceptable performance – Automotive
tubing / molded parts• Solutions
- metal filled material – induction heating sensitive additives in jacket and adhesive / blocking layers –induction heating for installation
• Reliable components supply and manufacturing process
Circuit Protection Circuit Protection Circuit Protection Circuit Protection –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
High and acceptable performance• Needs
- Low resistance – milli-Ohms for small components
- Low cost- Smaller, smaller and smaller – battery
pack surface mounted down to 0.5 mm by 0.5 mm
Circuit Protection Circuit Protection Circuit Protection Circuit Protection –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
High and acceptable performance• Needs
- Reliability, reliability, reliability- telecommunications - long- cell phone – two year lifetime- automotive – ten year life time
Circuit Protection Circuit Protection Circuit Protection Circuit Protection –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
High and acceptable performance• Solutions
- PE, PE co-polymers and fluoropolymers- Carbon black most common conductive filler- New products using metal powder
conductive fillers are being introduced- Processing is as important as the material
formulation – orientation- Co-60 and e-beam processing
Circuit Protection Circuit Protection Circuit Protection Circuit Protection –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
PTC Heaters PTC Heaters PTC Heaters PTC Heaters –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions• Needs
- range of auto- regulating temperatures
- range of power outputs (watts/meter)- longer lengths between power points- solvent resistance- abrasion resistance, indoor / outdoor
applications
PTC Heaters PTC Heaters PTC Heaters PTC Heaters –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions• Solutions
- Carbon black conductive filler- Olefin based heaters - 85° C shut off- PVDF based heaters - 110° C shut off- PFA / MFA based heaters - 121° C
shut off- product design – outer jackets / braids
PTC Heaters PTC Heaters PTC Heaters PTC Heaters –––– Market Needs, Market Needs, Market Needs, Market Needs, Materials SolutionsMaterials SolutionsMaterials SolutionsMaterials Solutions
Concluding RemarksConcluding RemarksConcluding RemarksConcluding Remarks
• Materials development market driven• Both high performance and acceptable
performance materials are complex and require significant development
• Product designers and materials formulators must work together
• Shift toward smaller product sizes, light weight and green
Concluding RemarksConcluding RemarksConcluding RemarksConcluding Remarks
• Available number of cross-linking polymers and additives is extensive
• Compounding route is a crucial part of the development process
• Small variations in composition, compounding can result in failure to qualify
• Education / experience concerns