PRESSURE SENSITIVE MANUFACTURER’S
ASSOCIATION
SELF ADHESIVE LAMINATES
INFORMATION DATA
© PSMA 2002
1
CONTENTS
A guide for the use of self-adhesive laminate roll and sheet
stock products
1
Choosing the right grade for specific applications
6
Glossary of adhesive terms
8
Odour and taint
9
Self-adhesive laminates
10
Variable information printing
13
Papers
16
Liners
18
2
A GUIDE FOR THE USE OF SELF ADHESIVE LAMINATE
ROLL AND SHEET STOCK PRODUCTS
HEALTH
Self-adhesive laminates are safe products in accordance with the material description
given by EC Directive 92/59, Article 2(b).
Material safety data sheets (MSDS) as referred to in Directive 88/379/EC, Article 10
and Directive 91/155/EC are not applicable to pressure sensitive materials.
Under normal conditions of handling, no hazards are anticipated provided normal
rules for good industrial hygiene are observed. Pressure sensitive adhesives are not
suitable for ingestion or prolonged skin contact.
For specialist applications such as food labelling, chemical drum labelling or surgical
labelling, advice should be sought from individual suppliers on specialist product
requirements.
FIRE
The materials involved will generally be flammable so should be stored away from all
sources of heat and ignition
Consideration should be given to listing the types of material stored in order to assist
the fire brigade in the event of a fire
In the event of fire Paper laminates will burn producing a black smoke, carbon
dioxide and carbon monoxide.
Plastic films pass through a melt stage and will therefore drip prior to burning, this
could cause severe burns if skin contact was made. Further information and specialist
advice should be obtained from your supplier
Vinyls will produce hydrochloric acid on burning as well as a dense smoke and other
acrid fumes. Specialist Protective clothing as well as breathing apparatus would be
required. For further information on all PPE (Personal Protective Equipment)
requirements contact your supplier.
WASTE DISPOSAL
All commercial waste is classed as controlled waste and as such must be disposed of
at a suitably licensed landfill site as required by the Environmental Protection (Duty
of Care) regulations 1991 and Control of Pollution Act 1974 and the Amendment
1989.
Waste laminate may also be incinerated for energy recovery, it is a useful alternative
fuel source. However, trails on suitability must first be carried out. The following
points should also be noted

Incineration of Acrylic adhesive based laminates should ensure the process
can handle corrosive flue gasses

Aluminium containing laminate is not recommended for incineration due to
possible blocking of the incinerator
3

As Vinyl laminates contains PVC, refer to the manufacturers for advice on
incineration.
STORAGE

Store all material on a clean dry floor or in racking.

All material should be stored in the supplier’s original packing until required
unless it has been advised otherwise

Reels stored on their side for long periods of time may pressure mark or form a
‘flat spot’

Avoid extremes of heat and humidity, ideal conditions would be 16 to 22oC and
50% RH+/-5%. High temperatures can cause adhesive bleed and penetration into
the face paper. Variations in humidity can cause curling and wavy edges.

Materials should not be stored near sources of ignition, in direct sunlight or UV
light.

Refer to the supplier’s recommendations on shelf life and ensure stock is rotated
as required
HANDLING

Safe methods of roll and pallet handling should be utilised

When un-banding pallets, care should be taken to avoid whiplash when the
strapping is cut. Appropriate PPE (Personal Protective Equipment) is
recommended, e.g. goggles and gloves

The outside wraps on a roll are to protect the product and should not be relied
upon to support a roll

Operators should be made aware that self-adhesive laminate reels could show a
tendency to telescope.

Care should be taken to avoid cuts from the exposed edges of the paper laminate
PROCESSING
Material should be allowed to condition in the print room for at least 24 hours before
processing in order to attain the same temperature and humidity. This is particularly
important for sheet stock, where 48 hours conditioning is recommended. Failure to do
this can result in curl and wavy edges.
There can be a build up of static during the conversion of self-adhesive laminates,
therefore conversion equipment must be adequately earthed. If flammable inks or
solvents are also in use, always refer to the supplier’s material safety data sheets for
safety information.
It is good practice to retain the manufacture’s batch and order reference information
in case a complaint should occur.
4
ROLL STOCK

Check that the ink or ribbon choice is compatible with the product to be used and
is recommended or approved by the suppliers.

Always check with the supplier if his material can withstand the intended process
conditions, particularly if excessive temperatures or unusual web feed patterns are
involved.

Do not change winding direction prior to conversion as this will alter the release
values and can create curl problems

Use the correct die for the product, check for damage prior to start up.

Labels should be designed with matrix stripping in mind. Refer to your supplier if
complex shapes are involved. Wherever possible use round corners and avoid
narrow matrices.

Check the depth of die cutting, especially before a long run. Excessive die
pressure will weaken the backing paper. Uneven die cutting can result in poor
matrix stripping.

With heat setting inks use the minimum heat required to cure inks and avoid
winding up hot reels

With UV cure-inks, always check the cure before proceeding with a run. Check on
age and output of the lamps involved.

Where heat is necessary, use minimum to achieve matrix stripping, excessive heat
(induced by use of hot plates) can create adhesive stringing, fouling of the labels
and heat built up in the reel. Always try to work to a fixed setting, returning to this
setting after large amounts of heat have been used.

Avoid rewinding reels to tight as this may cause adhesive bleed, conversely slack
wind will result in telescoping reels. Wind labels onto cores of appropriate size
e.g. large labels should not be wound onto small cores.

Converted reels should be stacked on end with waxed or siliconised interleaving
and covered in polythene prior to packing.
SHEET STOCK

Check that the print media is compatible with the surfaces to be printed

Allow sufficient unprinted edge trim on the screen to prevent edge lift due to
shrinkage

Avoid excessive use of thinners (refer to Material Safety Data Sheets) to prevent
shrinkage of filmic sheet stock

Use a minimum of heat to dry ink in order to avoid sheet curl

When using a jet drier for multi-colour runs, cover sheets in polythene between
runs to prevent sheet curl

When rack drying, avoid changes in temperature and humidity to prevent sheet
curl
5

Always allow sufficient time between passes for each colour to dry. This is
particularly important when flood coating

Print successive close register colours as soon as possible after each other.
Printing separate colours under different atmospheric conditions can cause
difficulties with register

Always follow the manufactures recommendations on guillotining and slitting

Finished work covered in polythene prior to packing.
SELF-ADHESIVE LAMINATES
Pressure-sensitive adhesives were first developed in the mid-nineteenth century for
self-adhesive bandages. However, it took ninety years for the idea to be adapted to
self-adhesive labels. Early adhesives used natural rubber and were applied by coating
from a solvent solution. Although the product adhered well to a wide range of
surfaces, its ageing properties were not good, and the need to use large quantities of
solvent in the coating process was a disadvantage.
The subsequent introduction of acrylic adhesives overcame some of the shortcomings.
Acrylics have excellent ageing properties and are highly successful as water-based
emulsions. The water-based products are easy to coat and clearly eliminated the
hazards and environmental concerns linked with solvent coating. However modern
solvent-based adhesives coating systems have overcome many of these difficulties.
Hot-melt adhesives were introduced in the mid 1960’s. These adhesives can be
coated at very high speeds and very high coating weights because there is no drying
process involved. More recently, radiation curable 100% solids acrylic systems have
been developed.
Modern pressure sensitive adhesives thus break down into the following major
categories: -
Solvent Based
Acrylic
Permanent
(High Adhesion Level)
Removable
(Low Adhesion Level)
Water Based
Or
Opaque/Clear – even coloured possibilities
Hot Melts
Rubber/
Resin
Radiation
Curable
(UV/EB)
FULL SPECTRUM OF PERFORMANCE AVAILABLE
6
CHOOSING
THE
APPLICATIONS
RIGHT
GRADE
FOR
SPECIFIC
PERMANENT Vs REMOVABLE
Usually the first decision to be made will be the required level of subjective adhesion
of the self-adhesive label or decal to the final substrate. There is a broad spectrum of
performance available from laminate suppliers. It is important at this stage to have a
clear understanding of the substrate involved and the end performance required. For
paper labels, the definition of “permanent” is trivial – being simply an adhesion level
that gives paper tear on attempting to remove the label. However where the label
material is filmic then the major concern with strong substrates like vehicles or “white
goods” (Fridges, washing machines etc.) is to prevent the label or sign material from
“falling off” under the field conditions. The final result will depend a combination of
many factors: 
Adhesive formulation

Adhesive coating weight

Substrate type – High surface energy – e.g. steel, glass, painted metal
Low surface energy - e.g. plastic surfaces like HDPE, OPP

Substrate shape – Flat, contoured, cylindrical

Substrate flexibility – e.g. Squeeze tubes

If label is to be paper based – then label orientation (Machine/Cross direction)
may be significant.
When using non-paper self-adhesive labels then a measure of permanence is defined
(at least in the UK) by a standard (BS 4781) which assures an adhesion level greater
than 15 Newtons/25mm after 24 hours according to FINAT test method No.1.
Note : A complete copy of the FINAT Technical Handbook may be obtained from :
FINAT, Laan Copes van Cattenburch 79, NL 2585 EW The Hague, Netherlands
tel. +31 70 3123910 fax +31 70 3636348, email info@finat.com
For Removable applications, the situation is more complex.

Definition for paper labels:- Remove-ability without paper tear or adhesive
transfer

For filmic labels
- Film much stronger than paper – tear is usually not an issue
- Main concern – avoiding adhesive transfer
7

Typical adhesion of removable adhesive to steel/glass:
- Around 0.3 – 0.5 N/25mm (permanent greater than 1.2 N/25mm).

Key of low adhesion adhesives to papers is generally very good – Adhesive
transfer is generally not a problem

For filmic removable systems – the adhesion may tend to transfer over time to the
higher energy surface. Therefore choosing a permanent adhesive (with higher
adhesive key to the film) may actually be the best option.

Removability of paper labels from a paper substrate may simply depend on the
care taken by the end user.
SURFACES TO BE LABELLED – IMPORTANT CONSIDERATIONS

Surfaces may be deceptive. Substrates may be contaminated, friable and variable.
There is no substitute for a test carried out on the actual object to be labelled. For
example, glass may have a protective coating or anti-scuff agent on the surface.

Test for adhesion under conditions that are as close as possible to the end use.

Do not carry out the test on a flat, empty container when the end user is labelling
one filled with product.

.

Check whether the label is to be applied to a plain or a printed part of the pack
On plastic or filmic surfaces, substances that can migrate to the surface may be
present. Advice should be sought from suppliers since these can have a
detrimental effect on adhesion.
RECOMMENDED ADHESION TEST FOR END USE

Cut out several labels of the same size and in the same grain direction as the
proposed printed label.

Peel off backing and apply to object to be labelled in the same position as the
eventual requirement. Rub down lightly with fingers or a pad of soft material.

Ideally prepare several samples and place in an environment appropriate to the
application or end use. Pay particular attention to substrates that are likely to be
cold and / or wet at the end user.

Leave for 24 hours minimum before assessment of adhesion.
ASSESSMENT OF ADHESION

Examine visually for edge lift or other evidence of “spontaneous failure”
8

Lift up corner of the label and peel with a firm, slow pull.

Good adhesion should result in at least 30 % fibre tear (by area) in the paper label
with a permanent adhesive. Filmic labels can only be assessed by the peel force
required to remove the label.

Removable labels can be tested in the same way, but should be assessed for
acceptable levels of fibre tear, surface damage or adhesive residue when removed.

MOST IMPORTANTLY – ensure that wherever possible the actual approval as
to fitness for purpose is determined by the actual end user. The adage should
always be: “One man’s permanent is another man’s removable”. Do not make any
assumptions as to the actual required final performance.
From time to time, printers/end users may encounter adhesion problems and these can
be expensive as they occur after labels have been printed. It is recommended that
printers/end users carry out a simple adhesion check before proceeding with new
business, using specific self-adhesive laminates. It is at this stage that the definition of
“fitness for purpose” must be clear and unambiguous.
GLOSSARY OF ADHESIVE TERMS

Application Temperature. Usually quoted as the minimum temperature below
which the label system will not adhere satisfactorily. Substrates must be both
clean and dry for this property to have significance.

High temperature, heat resistant. An adhesive capable of retaining its
properties when used at high temperatures.Light stable, UV stable. An adhesive
for use with clear films or where labels will be exposed to direct sunlight.

Marine approved. A self-adhesive laminate construction, which complies with
BS5609, Adhesive Coated Labels for Marine Use. This certification requires full
testing of the material under seawater immersion conditions over a period of 3
months together with subsequent adhesion tests.

Pasteurisable. An adhesive system capable of withstanding typical pasteurisation
conditions used in the beverage bottling industry.

Permanent. An adhesive with high ultimate adhesion, where labels are not
intended to be removed. Available from standard to very high coating weights,
depending on end application.

Pigmented adhesive. An adhesive used for over labelling or masking heavily
printed or coloured surfaces.

Plasticiser resistant. An adhesive which when applied to PVC or other plastics
containing plasticisers maintains an acceptable level of performance.
9

Removable, peelable. An adhesive which has a low ultimate adhesion to a wide
range of surfaces. Careful choice of adhesive must be made, particularly for
surfaces like fabrics, paper and plastic.

Repositionable. An adhesive which permits removal and repositioning shortly
after application, prior to the development of ultimate adhesion.

Repulpable. An adhesive that is capable of being used in a paper re-pulping
process.

Semi Permanent. An adhesive system offering a certain degree of short-term
removability, but with ultimately more “permanent” characteristics.

Service Temperature. The recommended working temperature range for a selfadhesive label construction.

Textile, fabric, garment. An adhesive designed for application to textiles. It
may be permanent or removable in type, according to specific applications.
Careful choice of adhesive must be made particularly for sensitive materials, e. g.
suede, PVC, silk, leather.

UV detectable. An adhesive that becomes detectable under UV light.

UL approved. An adhesive label system that has been certified according to
defined standards through the Underwriter Laboratories of the USA.

Water removable. An adhesive that upon contact with water will have a reduced
adhesive bond, allowing clean removal. This property will be temperature and pH
dependent.

Water-resistant. An adhesive that is resistant to high humidity or immersion in
water.

Water-soluble. An adhesive that is completely soluble in water.

Weather resistant. An adhesive for use where labels are subjected to a variety of
external conditions.
ODOUR AND TAINT
Pressure-sensitive adhesives are manufactured primarily from polymers and resins
and are selected to meet the challenging requirements of conversion and end user
adhesion performance. Different adhesives will have a retained odour level
characteristic of their chemical type, but components are selected to ensure that the
odour level is minimised and, wherever possible, will be generally recognized as safe
by virtue of prior industrial experience of compliance with legislation concerning
labelling.
Since various foods will respond differently to different odours, the final assessment
of tainting, due to residual odour should be judged by the end user concerned.
10
SELF ADHESIVE LAMINATES
APPLICATIONS REQUIRING CAUTION
The PSMA advise that caution is exercised with the following applications. This list
and the examples given are not exhaustive and in many cases, products are readily
available which may give a satisfactory performance and it is strongly recommended
to contact the material supplier.
SURFACES THAT COULD BE DAMAGED BY EITHER APPLYING OR
REMOVING AN ADHESIVE PRODUCT

Animal skins and natural fibres, e.g. suede, leather, wool, silk.

Tarnishable metals, e.g. copper, brass, silver.

Weak bonded surface finishes, e.g. flock coated products, vehicle paint, some
recycled boards, certain papers, some over-varnishes on print, certain decorative
finishes.

Some plastics e.g. highly plasticised films like flexible PVC, polystyrene, acrylate
films, thin films.

Certain treated surfaces, e.g. optical lenses, certain glass finishes, some lacquered
films and boards.
APPLICATIONS WHERE IT IS DIFFICULT TO OBTAIN SATISFACTORY
ADHESION
 Rough surfaces where the adhesive contact with the surface is likely to be low,
e.g. wood especially unplanned or unfinished, highly textured and embossed
items, unglazed pottery, cork, some metal surfaces, expanded polystyrene and
foams, coarse weave fabrics.

Low energy surfaces such as untreated polyethylene and other polyolefins,
silicone treated or contaminated surfaces, PTFE, chemical anti-corrosion
treatments, certain printing inks, certain over-varnishes, certain treated textiles,
polyamides, decayed pre-treatments, waxed or greasy surfaces.

Cold and/or moist surfaces or environments where adhesive tack may be reduced
or deaden, possibly only momentarily, by low temperature or moisture eg
condensation bloom, deep-frozen goods.

Changes in temperature/humidity between label application and storage, e.g. paper
labels applied at room temperature but stored at chill may show wrinkling and
bubbling as condensation moisture is absorbed by the label, adhesive products
which work well at deep freeze may have a lower adhesion level at room
temperature.
11

Changes in shape of a product, e.g. a container labelled empty may bulge when
filled, pre-labelled shrink-wrapped goods.

Migration of mobile components within the product labelled including permeation
of volatile ingredients through containers, will interfere with adhesion, e.g. oils,
fragrances, plasticisers. If the migration occurs prior to labelling, a satisfactory
bond may not be achieved. However, although initial adhesion may be excellent,
migration after labelling may lead to disastrous failures at a later date.
 Curved surfaces especially those with a tight radius less than 25mm may show
label winging, e.g. phials, ampoules, spirit miniatures. Also irregular shapes
including items where there is more than one radius of curvature, or where the
label turns 90º round a corner.

Recycled Boards can be a problem as they are rough, the surface may be only
weakly bound and tend to be somewhat inconsistent in content by their very
nature.

Friable surfaces where adhesive tack may be destroyed, e.g plaster, rusty metal.

Contaminated surfaces, e.g. dust, dirt, flour, cement, will almost certainly deaden
adhesive tack on contact. Other contamination such as liquid contents, moisture
will reduce tack or interfere with the adhesion.

Gassing after label application may lead to eventual bond failure, eg
polycarbonate, fibreglass, sealant, certain plastic containers.

Repositioning i.e. removing a label to reapply elsewhere may distort the label to
such an extent that the second bonding is never satisfactorily achieved.

Using a label to close a container, or attach an item to another, or other
applications where the label itself is placed under strain may result in an
unsatisfactory bond.
APPLICATIONS WHERE SPECIAL ADVICE SHOULD BE SOUGHT PRIOR
TO USE

Direct food labelling.

Toy labelling.

Medical applications e.g. skin contact, blood bags, sterilisation processes.

Textile and garment labelling.

Promotional gimmicks.

Applications with toner fusing where elevated temperatures are involved, e.g.
laser and digital printing.
12

Outdoor use, UV exposure.

Hostile environments, including seawater and solvents and temperature extremes
of more than 80ºC and below –20ºC.

BS5609 (Marine immersion).

BS4781 (Pressure-sensitive adhesive plastic labels for permanent use).

Health & Safety applications e.g. safety hats, crash helmets, protective equipment.

Applications involving microwave use.

Taint sensitive applications e.g. within boxes of chocolates or cereals.

Applications with items of high value e.g. antiques or objet d’art.

Durable labelling, UL/CSA, applications requiring certification.
SELF ADHESIVE LAMINATES
REMOVAL OF SELF-ADHESIVE LABELS.
Most self adhesive labels are designed for specific end uses and are not intended to be
removed e.g. permanent, deep freeze. It is advisable that those are, e.g. removable
grades, should be evaluated for suitability in any particular application. However it is
appreciated that on some occasions it might be necessary to remove labels or adhesive
residue.
The methods available will depend on the nature of the self-adhesive and of the
particular item labelled. It is recommended that careful testing is carried out to derive
a suitable method of label or adhesive residue removal, which ensures that the
item/product itself will not be damaged or affected in any other way.
The following methods are amongst those that may be tried.
 Slow and careful peeling of the label. Residual adhesive may sometimes be
plucked off by dabbing with adhesive portion of the removed label.

Immersion in warm water, possibly containing detergent. Some abrasion, possibly
vigorous may assist with removal.

Some proprietary products, such as de-greasers and household solvents, may be
trialled in accordance with the manufacturers instructions.

In some cases it may be advisable to remove the paper or filmic label layer and
work only on the adhesive. In other situations the inherent strength of the paper or
film will actually aid label removal. Certain label materials e.g. filmic and metal
foils, may need to be scored or broken in some way to allow action to take place
on the adhesive layer.
13
For assistance with specific applications, please contact the material supplier.
VARIABLE INFORMATION PRINTING
Variable Information Printing (VIP) can be achieved by a series of printing
techniques including:

Dot Matrix

Direct Thermal

Thermal Transfer

Laser

Ink Jet
1. Dot Matrix or impact printing is a technique whereby a computer-controlled
print head creates a series of dots to form a printed character by means of
magnetically activated needles. These impact on to an inked ribbon that transfers
ink onto a face stock. Drying of the ink occurs by evaporation and/or absorption.
2. Direct Thermal or chemi-thermal printing utilises a thermally sensitive topstock. The top-stock contains an imaging layer consisting of a colourless dye, a
binding agent and other additives. With application of heat the components melt
and the image is formed by a chemical reaction.
The thermal head consists of a row of computer-controlled miniature heating
elements. This ensures the correct amount of energy is received by the top-stock.
A backing roll ensures adequate contact of the print head and paper.
The sensitivity of a thermal top-stock refers to the intensity of the image formed
given a known amount of energy (heat). The chemical formulation of the imaging
components can be designed to commence imaging at different temperatures. A
low sensitivity paper will begin imaging only at relatively high temperatures.
A static sensitivity curve shows the image intensity for a given temperature and
will therefore indicate the minimum temperature a thermal top-stock begins
imaging. A typical high sensitivity paper will commence imaging at around 70oC
whereas a low sensitivity paper will image from around 85oC. This is very
important when considering the end application of the thermal label. If the label is
likely to be subjected to temperatures of around 65oC then a low sensitivity paper
would be preferable.
14
Optical density
Static Sensitivity
2
1.5
high sensitivity
low sensitivity
1
0.5
0
0
50
100
150
200
Temperature (C)
The speed of printing is indicated by dynamic sensitivity graphs. These graphs
show the image intensity for a given amount of energy. Dynamic sensitivity is the
relationship between image density and energy input. High sensitivity papers tend
to have a smoother top surface that enables high-resolution printing.
Optical density
Dynamic Sensitivity
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
high sensitivity
low sensitivity
0
5
10
15
Head Energy
Thermal papers can also incorporate other coatings for protection. A top coated
paper will have resistance to mechanical abrasion, water penetration and
chemicals (solvents oils etc). The top coating also protects when used in
applications involving foods containing grease etc. A back barrier coating may
also be used to protect the thermal layer from migrating components in the
adhesive system itself and the adherend to which it is attached.
15
3. Thermal Transfer printing should be considered as a system comprising printer,
ribbon and receiving substrate. All three elements need to work together
satisfactorily to provide a solution for the customer requirement.
Thermal transfer printing utilises a ribbon coated with a thermal coated pigment.
The print head consists of a row of computer-controlled miniature heating
elements. The computer ensures the correct amount of energy is received by the
top-stock. A backing roll ensures adequate contact of the print head and paper.
The heat from the print head transfers the ink coating from the carrier ribbon onto
the top-stock to produce an image which solidifies on contact. Print heads are
described by the positioning of the thermal elements. Traditional types are “true
edge,” “corner edge” and “centre.” Over the last few years a new configuration
has been gaining ground. This is termed “near edge” and has been designed for
higher print speeds. Special ribbons are required to work in this type of printer.
There are four basic types of thermal transfer ribbons (TTR).

Wax based ribbons are used in general purpose labelling applications, bar coding,
shipping and address labels. Low energy print heads achieve good print transfer.
Receiving substrates are usually papers (coated, uncoated, gloss, vellums).

Wax/Resin based ribbons are used where a degree of smudge and scratch
resistance is needed. Medium energy print heads are required to achieve good
print transfer. Ideal for two dimensional and rotated bar codes and applications
where greater abrasion resistance is needed. Receiving substrates are usually
coated papers, vellums and filmics.

Resin based ribbons are designed for enhanced durability in chemical printing and
industrial applications. High-energy print heads are required to achieve good print
transfer. Very high abrasion resistance. Used for chemical drum labelling
applications, pharmaceutical labelling, outdoor labelling and automotive
applications. Receiving substrates are usually filmics.

Near Edge ribbons are specially formulated for printers utilising “near edge”
technology. These ribbons tend to be either wax/resin or resin based systems.
Thermal transfer ribbons are available as either monochrome or colour.
4. Laser This process starts by electrostatically charging a photo-conductive
imaging drum evenly over its entire surface. The drum is then exposed using a
scanning laser beam. The light discharges parts of the drum thereby producing a
latent image. As the drum rotates the charge on the drum attracts toner powder.
This is then transferred to the facestock and fused onto the surface by either high
temperature rollers (hot fusion) or, a lower temperature, cold fusion unit.
5. Ink Jet printing is based on the ability to produce and manipulate small droplets
of ink in a series of dots to create characters. The three most common systems
are: -
16

Continuous – a stream of dots are continually created, the ink droplets are
deflected to produce the characters and the unused ink is collected and recirculated.

Impulse – where droplets are produced as and when required.

Solid ink system – whereby ink is evaporated by a small heating element close to
the jet. Heating impulses cause the ejection of ink droplets to provide the
characters.
PAPERS
GLOSSARY OF TERMS
Paper Machine
Diagram reproduced courtesy of Angus Wilde Publications, Canada
Headbox [Wire] [Press] [Drying section] [Calendar]
[Winding]
1. Uncoated. Papers which are designed for basic conventional printing or variable
imprinting. This category includes
 Super-calendared, surface sized printing papers like Vellum. Relatively closed
surface for ink hold out.
 Machine finished (MF), surface sized papers like Data for impact and nonimpact printing. Relatively open surface for easy ink/toner anchorage
17
Calendar Stack
Diagram reproduced courtesy of The Paper Industry Technical Association
2. Machine Coated (MC) White papers, one side coated, with mid to high gloss or
matt finishes. Used for mid to high range quality printing with additional gloss
being achieved by over-varnishing if required. The range includes a light weight
paper with low stiffness for labelling small diameters and curved surfaces
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Blade Machine Coating Process
Diagram reproduced courtesy of the Paper Industry Technical Association
3. Cast Coated. A high gloss (mirror finish) coated white paper for high quality
multi-colour print work. The premium gloss finish is achieved by ‘casting’ off a
highly polished chromium drum.
Cast Coating Process
Diagram reproduced courtesy of the Paper Industry Technical Association
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4. Decorative papers. A range of finishes to enhance the visual appearance of the
label. These include:


Textured papers which give a tactile and visual effect to the papers by using laid
effects, ribbing, felts etc. a range of ‘olde world’ appearances are achieved which
are popular in wine, jam & preservatives labelling. These papers often include wet
strength and anti fungal features.
Metallics – tinted, vacuum metallised, laminated and holographic effects in a
range of shades colours and effects.
5. Coloured papers – a range of coloured papers is available based on vellum or
coated papers for promotional labels. Also a range of papers with a fluorescent
coating of a vivid radiant colour are available for display and price marking labels
These papers can also be supplied for use in lasers and copiers.
6. Functional Papers. Papers which often incorporate a special coating e.g. to give
high opacity or resistance to grease/oils etc. Also including imaging forming
coatings to be used in NCR form sets.
LINERS
Sometimes referred to as backing paper, sometimes as carrier and sometimes as liner.
These materials are normally siliconized and allow the label material to be accurately
die cut and dispensed.
GLOSSARY OF TERMS

Glassine. Papers that have been super-calendared to provide good transparency
(>38%) and thus allow optical sensors to see through the liner and detect label
edges for automatic label application. Glassine liners are also normally strong and
consistent in caliper (thickness) to allow accurate die cutting. These papers come
in a variety of colours with honey and white being the most common and in a
range of weights and thickness (60-80gsm, 55-70 micron being the most
common).

Kraft liners. White papers, sometimes one side coated, optimised to give good
lay-flat characteristics to provide excellent fan folding properties, roll to sheet
conversion and often used for A4 laser/ink jet/copier products. Normally white in
colour but in a wide range of weights and thickness (45-140gsm and 50-140
micron being the most common).

Copy-back. A PE coated white paper with an encapsulated impact sensitive copy
system. Used where single and multi form self-copying sets are required.

Filmic. Polyester (PET) and Polypropylene (PP) clear films. Used to give
enhanced wet out of the adhesive (due to the exceptional smoothness) and
improved strength where web snapping is critical either from a security or high
speed application requirement e.g. pharmaceutical and beer labelling. These films
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are light and thin in comparison to the paper liners (30-50gsm, 23-50 micron
being the most common).
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