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Adhesive Book

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About this book

This Adhesive Book by UPM Raflatac is your guide to making the right choice of adhesive for

a range of end-use applications. It identifies the problems encountered with different substrates and

environmental conditions and describes the composition and properties of the various adhesives

developed in response.

All UPM Raflatac adhesives are solvent-free and environmentally friendly, without compromising

performance. Some are presented in this book according to end-use, and fully comprehensivecharts provide a useful reference to UPM Raflatacs entire adhesive range. Should any questions

remain unanswered, UPM Raflatacs experts are only a phone call away.

Foreword 3

1. Classification of adhesives 4

1.1. Chemical composition 4

1.2. Carrier 4

1.3. End-use 5

2. Factors that influence adhesion 6

2.1. The substrate 6

2.1.1. Roughness 62.1.2. Humidity and moisture 6

2.1.3. Surface tension 7

2.1.4. Shape 7

2.2. Temperature 8

2.2.1. Labelling temperature 8

2.2.2. Service temperature 8

2.3. Resistance to oxidation and UV light 9

3. Test methods according toFINAT standards 11

3.1. Peel adhesion: FTM 1 and 2 11

3.2. Release: FTM 3 and 4 12

3.3. Shear (cohesion): FTM 8 12

3.4. Tack: FTM 9 13

4. UPM Raflatac adhesives in different

end-uses 14

4.1. Food labelling 14

4.1.1. Labelling glass substrates 15

4.1.2. Labelling plastic substrates 16

4.1.2.1. Labelling flexible packages 16

4.1.2.2. Labelling hard plastic

packages 17

4.1.3. Labelling cardboard 19

4.1.4. Direct food labelling 19

4.2. Personal care labelling 20

4.3. Home care labelling 20

4.4. Oil and industrial chemical labelling 21

4.4.1. Oil-type applications 21

4.4.2. Industrial chemical applications 21

4.5. Pharmaceutical and health care

labelling 22

4.5.1. Small diameters 22

4.5.2. Blood bag and infusion

bag labelling 22

4.5.3. Sterilization techniques 22

4.5.3.1. Autoclave 22

4.5.3.2. Gamma radiation 23

4.5.3.3. Gas 23

4.5.3.4. Electron beam 244.5.4. Luminescence 24

4.5.5. Migration risks 24

4.6. A4 25

4.6.1. A4 VIP applications 25

4.7. Wine and beverage labelling 26

4.8. Tyre labelling 28

5. Approvals 28

6. Index 29

7. Troubleshooting 30

Contents

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Foreword

Natural adhesives were in use well before the

time of Egyptian carvings that date back morethan three millennia and depict thin pieces

of veneer being glued to planks of sycamore.

Papyrus, an early non-woven fabric, contained

fibres of reedlike plants bonded together with

flour paste, while the gold leaf of illuminated

medieval manuscripts was bonded to paper

with egg whites. It wasnt until the latter half

of the 20th century, however, that the rapid

growth of industry had a profound impact on

adhesive technology.

Many synthetics were developed in the

laboratory to replace natural adhesives in

the marketplace. The demand for adhesives

that had an inherent strength, while also

being resistant to environmental conditions,

led to the development of high-performance

materials which have now found their way

into almost all commercial applications.

Along with industry as a whole,

tremendous innovation and development has

taken place in the pressure sensitive arena.

The first pressure sensitives were based on

natural rubber and natural tackifiers dissolvedin organic solvents. Gradually, some of the

natural rubber was replaced by synthetic

rubbers. Some synthetic tackifiers were also

developed, but still as solutions in organic

solvents.

The utilization of emulsion polymerization

for the production of waterborne acrylic

polymers introduced totally new possibilities

for the development of a new range ofpressure sensitive adhesives. UPM Raflatac

was one of the first companies to actively

begin the development and implementation

of this kind of adhesive for use with pressure

sensitive laminates.

The next step was the development of

emulsified tackifiers, which made it possible

to modify the adhesion properties of these

new adhesives. Waterborne acrylic adhesives,

in combination with solvent-free silicones,

made it possible to overcome many of

the shortcomings associated with solvent-

borne rubber adhesives. The main benefits

were improved convertibility, better aging

characteristics and, of course, the elimination

of the use of polluting and hazardous solvents.

The introduction of waterborne adhesives

presented a big challenge for the coating

process. To transfer-coat a waterborne polymer

emulsion with relatively low viscosity onto a

siliconized paper is in fact against the laws of

nature, but experience shows that this can be

done very efficiently.Today, it seems that most of the potential

of acrylic chemistry has been explored.

The future will certainly bring new adhesives

based on different chemistries. Accordingly,

it seems that the development of adhesives

will continue to offer our industry the main

challenge and the greatest potential.

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1.1. Chemical composition

Adhesives based on synthetic resins and

rubbers excel in versatility and performance.

Synthetics can be produced in a constant

supply and with consistently uniform

properties. In addition, they can be modified

in many ways and are often combined to

obtain the best characteristics for a particular

application.

Acrylic adhesives

Acrylics are a type of synthetic polymer which

fall into the thermoplastic resin family. They

provide strong, durable adhesion at normal

temperatures.

Acrylic adhesives are based on acrylic

polymers. Acrylic polymers are

characteristically tacky and they can be used

as pressure sensitive adhesives without anymodification. In general, acrylic adhesives

have good aging and UV-resistance properties.

They are polar in nature and therefore give

good adhesion to polar substrates, such as

glass and nylon.

Rubber-based adhesives

Rubber-based systems can either be made of

synthetic rubber, such as styrene butadiene

rubber (SBR), or natural rubber. Rubber-based

adhesives always contain tackifier resins

and possibly some other modifiers because

rubber is not fundamentally tacky. The UV and

aging resistances of rubber-based adhesives

are not as good as those of acrylics. Their

resistance to UV, in particular, is considerably

lower due to the properties of the raw material.

Rubber-based adhesives normally have good

adhesion to non-polar substrates such as

untreated polyethylene and polypropylene.

The properties of adhesion of both acrylic

and rubber-based adhesive types can be altered

through modification and careful raw material

selection.

1.2. Carrier

The carrier is the substance that carries the

adhesive before it is coated at the coating

station. The carrier can be water or a solvent,

or there can be no carrier at all, meaning that

the adhesive is in 100% solid form.

1. Classification of adhesives

Pressure sensitive adhesives can be classified according to the

chemical composition, carrier and end-use application.

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Water-based systems (dispersions)

In water-based systems the carrier is water.

After coating, the water evaporates in the

coaters drying channels.

Solvent-based systems

In solvent-based systems the carrier is a

solvent. The solvent evaporates during drying,

and it is normally circulated back into the

process.

Hot melts (100% solids)

Hot melts are 100% solids. No solvents have

been used. During the manufacture of

labelstock, the hot melt adhesive is melted and

pumped in its molten state to a coating head.

From the coating head, the molten adhesive

is pressed through a die to form the adhesive

layer.

Hot melt adhesives provide very good

adhesion to moist substrates. The limitation

of hot melts is their heat resistance: hot melt

adhesives will start to melt again if they are

exposed to very high temperatures in the end-

use application.

UV cross-linked systemsUV cross-linkable acrylics are a relatively

new technological development in pressure

sensitive adhesives. Like hot melt adhesives,

they are 100% solid. Prior to coating, UV

acrylics are melted, pumped to the adhesive

coating station in a molten state and cross-

linked with UV radiation after coating.

A photoinitiator in the adhesive starts the

cross-linking reaction.

The benefits of cross-linking include

increased chemical resistance, cohesion(see 3.3.) and heat resistance. UV cross-linked

acrylics therefore combine the best properties

of acrylic dispersions and rubber-based hot

melts resistance to water, chemicals, heat

and UV.

Using various techniques, all the above

adhesive systems can be based on acrylic or

rubber-resin raw materials. To llustrate this,

UPM Raflatacs adhesives are classified in the

following table.

Raflatacs RP adhesives are acrylic-based

permanents, the RR adhesives are acrylic or

rubber-based removables, the RH adhesives

are rubber-based hot melts, and the RC

adhesives are acrylic-based and UV cross-

linked.

1.3. End-use

Adhesives can also be classified according

to the end-use or type of adhesion. Some

examples of different adhesive types are

briefly explained here to give an idea of the

various possibilities in labelling.

Permanent adhesives are designed to stay

permanently on the labelling substrate. They

are designed for a variety of end-uses, such

as general purpose EAN bar code labelling inautomatic warehousing.

In some applications, it may be necessary

to remove the label from the substrate. In these

cases the adhesive needs to be removable. The

removability properties are strongly dependent

on the substrate and the storage conditions.

This issue is discussed in more detail later on

in this book.

One particularly interesting application

is washable adhesives. These adhesives are

permanent in nature but they can be washedaway when the label is no longer needed.

Labels with this type of adhesive are used on

returnable packages that can be used several

times, such as bottles or plastic boxes.

Water-based Solvent-based Hot melts UV cross-

adhesives adhesives linked adhesives

Acrylic RP adhesives none none RC adhesives

based RR 28

Rubber RR 21, RR 22 none RH adhesives none

based

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The following paragraphs explain how the

substrate and the labelling, storage and

service conditions influence adhesion. These

factors are relevant for both permanent and

removable adhesives.

2.1. The substrate

2.1.1. Roughness

A substrates roughness or smoothness

affects the contact area of the adhesive. If the

substrate is very rough, contact can take place

only on top of the hills and the valleys will

not be in contact with the adhesive. The total

contact area will be small and the resultant

adhesion low.Accordingly, a permanent adhesive for

rough substrates must properly wet the

valleys. This can be achieved either by

raw material selection or by using a higher

adhesive coat weight.

For removable adhesives, rough substrates

are undemanding. Removability is not

a problem it is very rare that the adhesion

would be too high for a rough substrate.

It is much more likely that the adhesion is

In principle, adhesion can be described as the ability of the adhesive

to wet the substrate and then bond to it. After labelling, pressuresensitive adhesives start to flow and build up contact with the

application surface.

2. Factors that influence adhesion

Good adhesion to cardboard, HDPE drums and jute requires careful raw material selection or

a higher adhesive coat weight because the total contact area is small.

Moist substrates are a real challenge for theadhesive.

too low, which results in labels that come

loose from the substrate. It follows that the

level of adhesion provided by a removable

adhesive must be tested before its commercial

application.

2.1.2. Humidity and moisture

Substrates are sometimes moist. This is a

real challenge for the adhesive. In the food

industry, products are often labelled in a

chilled area where condensation forms very

easily on the labelling surface. Another

example of conditions that involve damp

substrates is outdoor labelling.

Water-based adhesives are able to absorb

and therefore tolerate a certain amount of

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2.2. Temperature

The properties of adhesives are affected by

temperature. With various modifications,

some adjustment can be made to an adhesives

application temperature range.

At low temperatures, adhesives become

harder. This decreases adhesion particularly

immediate adhesion.In higher temperatures, adhesives soften.

This is the result of decreased internal

strength. Softening may increase adhesion to

a certain extent because it helps the adhesive

to flow and the contact area with the substrate

increases. However, if an adhesive gets very

soft it begins to loose its adhesive properties.

Also, an adhesive has a greater tendency to

bleed as it softens.

2.2.1. Labelling temperature

The optimal labelling temperature for

an adhesive is normally close to room

temperature.

As a general rule, it can be said that if

labelling takes place below 0 C or on a cold

package (-20 0 C), then a deep freeze

adhesive should be chosen, such as RP 48.

General purpose permanent adhesives

like RP 51 and RH 1 are designed for chilled

areas (0+5 C) as well as room temperature

applications for various end-uses.

2.2.2. Service temperature

If labelling is carried out at near room

temperature and the adhesive has time to

develop a bond with the substrate, it will resist

higher or lower temperatures during storage.

As a consequence of their manufacturing

technique, hot melt adhesives melt when

exposed to high temperatures. Deep freeze

adhesives are fine-tuned to maintain adhesionin cold environments, and this detracts

from their heat resistance. General purpose

permanents have medium heat resistance,

which is typically guaranteed for up to 80 C.

An adhesive with high cohesive strength

(shear) is recommended for applications that

involve very high temperatures. This kind

of adhesive provides good heat restance. RP

A4 is an example that has been specially

developed for A4 copier and laser applications.

When labelling takes place below 0 C or on

a cold package (-200 C) the safest choice

is a deep freeze adhesive such as RP 48,

which doesnt loose its adhesion properties at

low temperatures.

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2.3. Resistance to oxidationand UV light

In practice, oxidation means aging. High

temperatures increase the rate of oxidation.

Acrylic adhesives are not particularly prone tooxidation and therefore have a long shelf life.

In contrast, rubber-based adhesives normally

contain components that are more sensitive to

oxidation. However, stabilisers can reduce the

oxidation rate of rubber-based adhesives so

that their shelf life is similar to that of acrylics.

When oxidation occurs the adhesive starts

to yellow, gradually looses its properties of

adhesion and finally becomes very hard so that

it is not tacky at all. This happens over time to

all adhesives, and it is for this reason that shelf

life recommendations are essential.

Ultraviolet light can adversely affect the properties of adhesives.

UV light has the biggest effect when an

adhesive is combined with a clear filmic

material. Unmodified acrylics have excellentUV resistance, whereas rubber-based

adhesives are rather poor in this respect.

The term `shelf life refers to the time

for which a laminate (the face material and

adhesive combined) can be stored at constant

temperature and humidity with no affect on

the adhesives properties. Shelf life does NOT

normally refer to the life expectancy of a label

after application onto a product.

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113.1. Peel adhesion:FTM 1 and 2, peel at 180 and 90

respectively

The peel test describes the permanence of

adhesion or peelability of pressure sensitive

adhesives. Test strips 25 mm wide are adhered

to a standard test substrate made of glass or

steel. Using different strips, the adhesion is

measured after 20 minutes and 24 hours. The

strips are peeled off at an angle of 180 or

90, and the force required to remove them is

recorded in Newtons.

The peel at 90 can be used to compareadhesive performance even with different face

materials. This is because the flexibility of the

face material has less influence on the result

than it does in the 180 test. Peel adhesion at

180 is only safe for comparison with face

materials of similar flexibility.

For removable adhesives the peel test

is very useful differences in adhesion are

easily seen in this test. The peel test can

also be modified to measure the peel of an

adhesive on different substrates such as PE

and cardboard.

For permanent adhesives the peel test is

not that relevant not at least as a quality

assurance test because the result with paper

laminates is usually paper tear. This meansthat the paper is weaker than the adhesion

provided by a permanent adhesive. Peel tests

can be performed with permanent adhesives

only when the face material is a filmic,

preferably polyester, which does not stretch

during the test.

The test methods for adhesives are standardized by FINAT.Some of these tests, FTM 1, 2, 3, 4, 8 and 9, are described below.

3. Test methods according to FINAT standards

The peel test measures the performance of

removable adhesives. Pictured left is peel

adhesion at 90.

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3.2. Release:FTM 3 and 4, low and high speed release

tests, 300 mm/min and 10300 m/min

The release test measures the force needed to

separate the face material and adhesive from

the liner. The measurement is conducted at

an angle of 180, and the required separation

force is measured in centiNewtons. Test stripwidths of 50 and 25 mm are used in the low

and high speed tests respectively.

Release is an important property for both

label converting and dispensing. A release

value that is too high can cause web breaks

during matrix removal and dispensing failure

on the dispensing line. A too low release

force can cause labels to pre-dispense at the

dispenser.

Normally, the release value can vary to

a certain extent without causing problems.

The release value needs to be clearly out of

specification before severe problems occur.

An uneven release is much more critical than

a release that is too high or too low: it causes

problems both when removing the waste

matrix and during label dispensing.

3.3. Shear (cohesion):FTM 8

Shear, or cohesion, describes the internal

strength of the adhesive. It is measured as the

time taken to split the adhesive layer. In theevent of cohesive failure, adhesive residue is

left on both the substrate and the face material

the actual adhesive bond is not broken.

The test is performed by adhering a

25 mm x 25 mm square of adhesive-coated

face material to a near-vertical standard

substrate. A 1 kg weight is suspended from

the test piece, and the time it takes to slide

off the substrate is measured. The lower the

shear value (the less time it takes to split the

adhesive layer) the softer the adhesive.

High shear normally indicates good heat

resistance, less bleeding, low adhesion at

low temperatures, moderate initial adhesion

and good convertibility. As a general rule,

The internal strength (cohesion) of an adhesive is measured with the shear test.

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adhesives for laser printing or other high

temperature applications A4 applications,

for example have high shear values.

Adhesives for deep freeze applications

normally have low shear values, typically

of around one hour or less. Deep freeze

adhesives are designed to maintain adhesion

in cold environments, so they are soft at room

temperature.

3.4. Tack:FTM 9, `quick-stick measurement

Tack is used to describe initial adhesion. The

tack value is the force needed to separate an

adhesive-coated face material from a substrate

after a very short contact time. In the FINAT

test, a strip of test material 25 mm wide is

made into a loop. The loop is brought into

contact with a glass substrate and removed

immediately. The contact area measures

25 mm x 25 mm, and the speed of contact

and removal is 300 mm per minute. The

force required to remove the test material is

measured in Newtons.

The tack value tells about the immediate

adhesion on a substrate that is polar and

smooth. Very often, tack and shear are

interdependent: if the tack value is very high,

then the shear is normally rather low.

In other words, softer (low shear) adhesives

wet the substrate quickly and have high initial

adhesion. It follows that adhesives with

a higher shear value have a lower tack.

The `quick-stick

measurement measures the

tack (initial adhesion) of

the adhesive.

The shear test measures

the time taken to split the

adhesive layer using a 1 kg

weight.

The release test.The peel test at 90.

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4.1. Food labelling

Food labelling is by far the biggest end-useapplication in terms of volume. In addition,

food and nutrition labelling remains an

important issue for consumers: it is a broad

term that encompasses several items required

on food packages by law and other regulations.

Food labelling encompasses a statement of

net contents, the name and address of the

manufacturer, ingredients and nutrition, and

claims regarding nutrition and health. All

of this accompanies the brand and product

identity statement that the manufacturer needs

to differentiate its particular product from the

many other products competing on the same

shelf.

As a result of consumer concerns and

other packaging issues, food labels are

often stored in a variety of conditions onceapplied. These conditions have a direct

influence on the choice of materials used

in the construction of the label itself. For

example, cold environments can lead to the

formation of condensation on the surface of the

package to be labelled. An adhesive for these

circumstances must provide good adhesion

to moist substrates as well as a good level

of adhesion in chilled areas. UPM Raflatacs

RP 51 for paper labelstocks and RP 37 for

filmics serve this purpose in normal cases:

they are suitable for labelling in chilled areas

and have good adhesion to plastic substrates

and surfaces that are slightly moist. RH 1 is

necessary if the substrate is really moist.

4. UPM Raflatac adhesives in different end-uses

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4.1.1. Labelling glass substratesGlass is normally a simple substrate for

pressure sensitive adhesives to work with. Its

surface tension is high, which means that it is

easy for the adhesive to bond to. In addition,

glass is usually a very smooth substrate

that allows the adhesive to make use of the

maximum contact area.

In some cases, certain surface treatments

are applied to protect glass surfaces from

abrasion on bottling lines, for example.

Silicone derivatives, among others, can be

used for these topcoats but, understandably,

they tend to make adhesion more difficult.

On glass substrates, RP 51 is typically used

with paper labels RH 1 can also be used.

RP 37 is used with filmic face materials.

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4.1.2. Labelling plastic substrates

4.1.2.1. Labelling flexible packages

Soft plastic packages are often multilayer

constructions that comprise different films,

laminated together to combine the advantages

offered by each material. Typically, the

substrate to be labelled (and possibly

printed) is oriented polypropylene (OPP),

polypropylene (PP), polyester (PET) or

polyamide (PA, nylon).

PP and OPP have a low surface tension,

and this provides a greater challenge for the

adhesive. PET, however, has a high surface

tension which makes it a far easier substrate

for adhesives in general.

From the perspective of adhesion, it is

unfortunate that packaging films are rarely

without surface treatments, with anti-fogging

and slip agents often added to the film.

Plastic ice cream packages present many challenges for the adhesive. It must perform well in

conditions ranging from -20 C to room temperature.

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Antifogging agents lower a substrates surface

tension, which makes it more difficult to

adhere to. Slip agents lower the friction

of the film, but they also detract from the

performance of pressure sensitive adhesive.

In the food industry, where soft andflexible packaging is commonly used, low

temperature labelling conditions prevail. The

combination of a cool substrate and humidity

can prove demanding, and an adhesive that

can perform well in these conditions requires

special development.

Raflatac answers this need with RP 51

a general purpose permanent adhesive suitable

for labelling in chilled areas. It has good

adhesion to substrates like PP and OPP, and

it can tolerate a certain amount of moisture

on the substrate during the labelling process.

However, if the substrate is very moist, RH 1

is the right solution.

4.1.2.2. Labelling hard plastic

packages

Hard synthetic food packaging includes blow

and injection moulded and thermoformed

packages.

Typically, paper-based face materials are

served with RP 51, and films with RP 37.

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Extremely smooth, printed and varnished

cardboards are not especially problematic for

adhesion.

One of the most difficult substrates among

cardboard labelling is corrugated board.

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4.2. Personal care labelling

The main issues to be considered in personal care

labelling are the clarity and wet-out of the adhesive

and the labels overall resistance to UV light and

water.

Typical personal care labelling applications

involve HDPE, PP, PET and glass bottles and

containers. It is important that the adhesives have been

developed to give good adhesion to HDPE and PP,which are naturally demanding for acrylic adhesives.

PET and glass are polar in nature, so acrylic adhesives

normally have very good adhesion to these substrates.

Squeezable and complex shaped containers demand

higher adhesion to assure good label performance.

Tube and wet wipes labelling are extreme

examples of applications in personal care. Tubes

demand high adhesion and good flexibility from

the label for maximum squeezability without the

formation of wrinkles and creases. Wet wipes

applications require very good open-closure properties

and resistance to water and chemicals.

Most label products for personal care are tested

against the contents of the bottle or container.

Resistance against substances such as oil, fragrances

and vitamins is very important. One of the most

demanding applications in this respect is sun care

product labelling.

UPM Raflatac recommends RP 37 for all standard

applications where the labelstock has a paper

backing. RP 74 is the first choice for clear-on-clear

applications, and RC 12 a good solution for open-

closure labelling on wet wipes packages.

4.3. Home care labelling

Containers in home care labelling are often bigger

and the surfaces rougher than those in personal care.

Resistance to water and chemicals such as tensides,

soap, oil and fragrances or even solvents is required.

Sometimes the containers are freshly blow-moulded.

The labels may wrinkle if applied before the container

is in its final shape. Here the balance between the

labels adhesion and flexibility is crucial.

For applications with standard requirements and

filmic face materials, UPM Raflatac recommends

RP 37. RP 77 is an appropriate choice where higher

adhesion is required. If water resistance is not

required, paper face materials can be combined with

RP 51 or, for slightly humid conditions, RH 1. Special

attention needs to be paid if paper face materials are

applied to freshly blow-moulded containers.

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4.5. Pharmaceutical andhealth care labelling

No other industry has such wide-ranging label

applications as the pharmaceutical industry.

There is a very high level of product

differentiation, and specification to match.

Approvals, certificates and technical

information documents are often required.The following paragraphs cover some

of the demanding areas associated with

pharmaceutical labelling small diameters,

various sterilization techniques, adhesive

migration and luminescent label detection, for

example. Careful research into the specific

needs of the end-user is required in each case.

4.5.1. Small diameters

Syringes, test tubes and small diameter

medicine packs ask a lot from their labelling

materials. Test tube materials vary from glass

to PE and PS (polystyrene), for example.

Labelling normally takes place at room

temperature but the service conditions may

range from cold storage to a warm water bath.

The thin, flexible paper-based face materials

used on these small diameters should be

combined with an adhesive that has high

cohesion, such as RP 31. Filmic face materials

perform well with RP 37.

4.5.2. Blood bag and infusion baglabelling

There are two stages to labelling a blood bag

or infusion bag. In the first stage, the bags are

labelled during their manufacture. The soft

PVC blood bags contain plasticizers which

cause adhesives to soften, so for direct contact

special adhesives are required.

In the second stage, a new label is

applied over the existing label from the

bags manufacture. This secondary blood

bag labelling takes place after the bags havebeen filled with blood at blood centres or

hospitals. Secondary labels mostly contain

information about the blood. The blood may

have been separated into red cells, plasma and

thrombocytes, which are stored in different

conditions.

The adhesives RP 31 C, which has non-

migration properties, RP 31 and RP 37 have

been used for many years in secondary blood

bag labelling.

4.5.3. Sterilization techniquesThe four most common sterilization processes

are steam (also called autoclave), gamma

radiation, gas and electron beam. Choosing

the right face material and a suitable

adhesive requires a knowledge of how these

sterilization systems work and the effect they

have on pressure sensitive materials.

4.5.3.1. Autoclave

Autoclave sterilization is done under pressure

with steam, at high temperatures. Non-woven

materials or sterilization bags made by sealing

paper and polyester together are exposed to

this process, for example. The adhesives

RP 31, RP 31 C and RP 37 (for filmic labels)

should be tested first. The test results should

be based on the longest exposure at the highest

temperature.

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4.5.3.2. Gamma radiation

Some companies specialize in sterilization

with gamma radiation. The process takes some

hours and is intended for the mass sterilization

of several pallets at the same time. General

gamma radiation can break down the strengthof materials, but this wont happen with the

doses normally used in this process. It is

possible that paper could discolour a little.

With the exception of soft adhesives

deep freeze and removables, for example

all UPM Raflatac adhesives are suitable for

gamma sterilization.

4.5.3.3. Gas

Gas sterilization is carried out using ethylene

oxide in conditions with increased temperature

and humidity. An adhesive must have good

heat resistance to tolerate this process. After

several hours, the ethylene oxide is evaporatedand degassing takes place. Intended for larger

quantities, the entire sterilization process

can take more than 24 hours, and optional

degassing up to seven days more.

UPM Raflatacs adhesives have been

tested for gas sterilization. Please refer to the

adhesive recommendations charts at the back

of this book.

Small diameters are among the many challenges to be met by

adhesives used in pharmaceutical and health care labelling.

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4.5.3.4. Electron beam

High voltages are also used for sterilization.

An electron beamer is used to produce

extremely high voltages of between 5 and

10 megavolts, and products exposed to

this voltage are sterilized in a few seconds.Because this technique is less penetrative than

gamma radiation, large batches are divided

before sterilization.

All UPM Raflatac adhesives are suitable

for e-beam sterilization, though deep freeze

and removable adhesives should be tested first.

4.5.4. Luminescence

In the pharmaceutical industry, all products

must be labelled or preprinted to secure their

traceability and date of expiry. When using

clear filmic labels, it is not so easy to detect

their presence. The solution is to incorporate

a luminescent additive into the adhesive

so that the label can be detected by special

luminescent detectors. UPM Raflatacs RP 35 L

has been developed for this application.

RP 35 L is used in combination with clear PE,

PP or PET face materials. A PET 30 backing

is recommended to give a good wet-out and

assure the clarity of labels once they have

been applied.

4.5.5. Migration risks

Glass has been used in the pharmaceutical

industry for many years. It has always been

a safe packaging material. Today, the pharma

industry is constantly looking for new

alternatives to glass synthetic packaging

is being used more and more. Labelling on

synthetics, however, is entirely different to

labelling on glass, not only from the point

of view of adhesion, but also because of the

migration risk. LDPE is the most critical

synthetic substrate in this respect.

When using pressure sensitive labels on

LDPE eye-dropper bottles, for example, the

adhesive could migrate through the LDPE

and into the liquid. To avoid this migration,

UPM Raflatac recommends RP 31 C.

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4.6. A4

Laser printing and copying has its own

particular needs. An adhesive for this purpose

must withstand the heat of the hot fusion

process and mustnt bleed out from the edgeof the sheet before or during printing. The

adhesive should also cut well during the

sheeting process in order to have clean edges.

UPM Raflatacs A4 adhesives the

permanent RP A4 and removable RR A4

have been specially developed for laser

printing and copying and its demanding

labelling applications.

4.6.1. A4 VIP applications

A4 variable information printing includes a

very wide range of applications. An adhesive

that performs well in so many different end-

uses requires special development.

Home and office applications (address

labels, for example) are generally straight-

forward; there are no special requirements set

on the adhesive. CD labels are the exception,

where good adhesion to the lacquered disk

surface is required. Removable adhesives are

not recommended because removing the label

can destroy the disk.

In industrial use, cardboard boxes aretypically labelled with laser-printed labels

that contain product and delivery information

in the form of bar codes. Good adhesion is

required on cardboard and PE wrapping, and

in cold environments such as warehouses.

In laboratory use, test tube labels must

have good adhesion to a variety of substrates

test tube materials vary from glass to PE and

One of the most important properties of an

adhesive for office applications is its ability

to withstand the heat generated by laser

printing and copying.

PS, for example. In addition, small diameter

tubes need an adhesive that has good internal

strength (cohesion), combined with a flexible

label material.

RP A4 and RR A4 deliver good

performance in all these applications.

A4 VIP applications range from heavy-duty industrial applications to home and office

applications. The adhesive is typically required to have good heat resistance and perform well on

a variety of substrates.

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4.7. Wine and beveragelabelling

During the lifecycle of a bottle, the label and the

adhesive are subjected to a variety of conditions.

During the bottling process, the adhesive must

provide the best tack in manual and automatic

applications, possibly at low temperatures and

in humid conditions. While adhesives on whitewine, champagne and even beer bottles must

endure refrigeration, water and ice, red wines,

other FABs and NABs are usually served in dry

conditions. The adhesive may be required to

perform well in long-term storage in cold and

humid cellars, and bottle recycling requires an

adhesive with good wash-off properties.

Good contact between the adhesive

and the glass is necessary to minimize the

labels reaction to changes in humidity or

temperature. In areas where proper contact

does not occur, a face paper is more likely to

swell or shrink. Excessive irregularities in the

bottle are undesirable: areas where there is no

contact between the label and bottle may not

be immediately visible, but they can often lead

to the development of bubbles or wrinkles in

paper and filmic face materials.

It should be noted that labelling wet (not

moist) bottles is impossible for any adhesive,

especially when using automatic application

machinery. The label will simply slide on the

bottle, be incorrectly positioned and formwrinkles and creases.

UPM RAFLATAC RECOMMENDS THE

FOLLOWING ADHESIVES FOR WINE AND

BEVERAGE LABELLING APPLICATIONS:

RP 40 is a modified acrylic dispersion

adhesive for paper labels and has been

especially formulated for wine labelling. A

good choice for all wines, RP 40 tolerates

fluctuations in temperature and humidity, onthe bottle line and during bottle storage. It

provides good adhesion to polar surfaces and

can be washed off in hot alkaline water. RP

40 also has good water resistance in the ice

bucket (minimum 3 hours).

RP 37 is an acrylic dispersion adhesive

specially designed for filmic face materials

on paper backings. It has good clarity when

combined with clear films. RP 37 is also UV-

stable and water resistant, and has good

adhesion properties and heat resistance.

RP 74 is an acrylic dispersion adhesive

with excellent clarity and resistance to water

whitening. This adhesive is available with

Raflaclear PP TC 50 face on a PET 30

backing for a crystal clear wetout.

The new formulation of the RP 74 adhesive

also allows easier and faster conversion

without compromising good adhesion to glass

or PET substrates. UPM Raflatacs Raflaclear

labelstock is ideally suited to fashionable no-

label look wine and beverage bottles thatportray an original and creative image.

RH 1 is a rubber-based hot melt adhesive

that provides good adhesion to non-polar

surfaces. RH 1 is recommended for labelling

red wines and liquors only.

For additional information and support, or

consultation concerning pasteurization, please

feel free to contact your local UPM Raflatac

representative.

WHEN DECIDING WHICH ADHESIVE TO

USE, THE BOTTLER OR PRINTER MUST

TAKE INTO ACCOUNT THE FOLLOWING

PARAMETERS:

Bottle surface treatments

Protective surface treatments applied to bottles

are designed to increase scratch resistance

while the bottles are being processed through

bottling lines and ensure that

the bottles run smoothly

through the machinery. The

surface treatment might havean adverse effect on adhesion,

in which case RP 40 is

the normal solution.

Condition of the bottle

at the time of labelling

Ideally, bottles should

be washed and dried

before labelling. The

temperature of the

bottles should beabove 15 C during

labelling and the relative

humidity should not

exceed 55 %.

Different wines, different service conditions.

The conditions on the bottling line and the

need for water-washability should also be

considered when choosing an adhesive for

wine labelling.

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Bottle recycling

If the bottle is to be recycled, a special

adhesive such as RP 40 is required. A standard

adhesive would stay on the bottle even after

the wash-off process. During the wash-off

process, alkaline additives in the water passthrough the labels face paper, the adhesive

washes away and a high-pressure water jet

removes the label. The thicker the ink layer,

the more difficult it will be for the water to

penetrate through to the adhesive and remove

the label. Washability can be seriously reduced

by hot foil printing or UV varnishing.

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4.8. Tyre labelling

Tyre labelling presents a real challenge for

pressure sensitive adhesives. Not only because

of the roughness of the substrate but also

because of the chemical composition of the

tyre rubber.

Tyres are normally labelled at room

temperature by hand. The contact area between

the label and the tyre surface is rather small

because of the uneven tyre profile, so very

aggressive immediate adhesion is required.

Once labelled, the storage conditions for tyres

can vary from room temperature to warmer or

colder conditions in warehouses or outdoors.

Accordingly, the adhesive must maintain its

properties in low and high temperatures.Uneven tyre surfaces are demanding

enough as it is. To make the challenge even

greater, wax or silicone-based chemicals

used as mould release agents during the

tyre manufacturing process are very often

present. An adhesive for tyre labelling must

also withstand the migration of certain

chemical components from the tyre rubber.

These components cause the label to yellow

if the labelling materials are not resistant

to migration. UPM Raflatacs RH T ahigh tack, high coat weight adhesive has

been specially developed for tyre labelling

applications.

An adhesive for tyre labelling must resist the

migration of chemical components from the

tyre rubber.

Rough tyresurfaces

require

aggressive

immediate

adhesion.

5. Approvals

There are several different requirements

for adhesives developed for use with food

packaging. Approvals for indirect food

contact can be attained by testing the product

itself at an independent research laboratory

or by relying on FDA (Food and Drug

Administration, USA) publications. The FDA

tests, makes reports and releases publications

on the chemical components that can be used

for food contact or food packaging.

Research laboratories normally test the

migration properties of a product according to

national or international standards. Different

simulants are used in these tests to predict

suitability. For example, water is used to testsuitability with moist foods, while ethanol or

heptane are used as simulants for fatty food.

Numerous industrial applications require

that a label has BS5609 part II Marine

Use approval. This approval relates to the

adhesives and face materials used to label

dangerous goods transported by sea: it sets

conditions for the laminates performance in

terms of sea immersion, dimensional stability,

adhesion, temperature cycling, artificial

weathering and colourfastness. BS5609 part IIIrelates to the performance of the printed label,

including the print, and it is the responsibility

of the printer to comply with this approval.

More information is available at

www.upmraflatac.com.

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25 A4 applications

4 acrylic adhesive

28 approvals

26 beverage labelling

19 cardboard

4 carrier

25 CD labelling

4 chemical composition

12 cohesion

6 condensation

12 converting

25 copying

6 corrugated cardboard

8 deep freeze adhesive

19 direct food labelling

12 dispensing

5 dispersion

21 drum

19 fatty food

19 FDA11 FINAT

14 food labelling

19 fruit labelling

8 general purpose permanent

adhesive

15 glass labelling

21 HDPE containers

8 heat resistance

12 high speed release

20 home care labelling

5 hot melt6 humidity

13 immediate adhesion

21 industrial chemical applications

19 ISEGA

8 labelling temperature

25 laser printing

12 low speed release

19 meat labelling

24 migration

6 moist substrate

25 office labelling

9 oxidation

16 packaging films

11 peel

20 personal care

22 pharmaceutical labelling

12 release

4 resin

6 rough substrate

4 rubber-based adhesive

4 SBR, styrene butadiene rubber

8 service temperature

12 shear

9 shelf life

22 small diameter5 solvent-based adhesive

6 substrate

7 surface tension

13 tack

8 temperature

11 test method

22 test tube labelling

7 tight, convex radius

28 tyre labelling

5 UV cross-linkable adhesive

9 UV light25 variable information printing

19 vegetable labelling

27 washability

26 wine labelling

6. Index

page

29

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7. Troubleshooting

Problem

Adhesion too low

Edge-lift on a small

diameter application

Poor removability

Poor wash-off

Odour

Penetration

Bleeding

Appearance

Corners of the label are

lifting

Labels are coming loose

Corners of the label

are lifting

Label doesnt remove

cleanly

Odour during printing

Odour in ready printed

labels

Greasy-looking labels

Disappearance of the

thermal image

Cause

Pressure during application

too low

Face material too rigid

(for uneven substrate)

Incorrect product

Face material too rigid

Incorrect choice of adhesive

Water too cold

No washing agent

Printing or varnishing toocompact

Incorrect product

Odour in the adhesive

Odour from the print

(UV inks especially)

Adhesive penetrationthrough the face material

Labelling of plasticized

PVC, plasticizer migration

Plasticizer migration

Storage temperature too high

Too high winding tension

in coils

Too high winding tension

in label rolls

Action

Check other face material possibilities with

the supplier

Contact the supplier with information about

the intended end-use

Contact the supplier with information about

the intended end-use

Check other face material possibilities with

the supplier

Contact the supplier with information about

the intended end-use

Contact the supplier with information about

the intended end-use

Check recommendation for the washing

conditions from the technical information sheet

Check recommendation for the washing

conditions from the technical information sheet

Leave some area unprinted

Contact the supplier with information about

the intended end-use

Contact the supplier with the order details

Check the curing of the ink

Contact the supplier with the order details

Use barrier-coated labels, contact the supplier

with information about the intended end-use

Use barrier-coated labels, contact the supplier

with information about the intended end-use

Check the possibilities for normal temperature

storage

Contact the supplier with the order details

Check the winding tension after matrix

removal

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