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Glossary



Abrasion Resistance

The resistance of a surface to rubbing or wearing away by friction.

   

Accelerated Aging

Procedures for subjecting pressure sensitive materials to special environmental conditions in order to predict the course of natural aging in a much shorter period of time.

   

Accreditation

These often take the form of a letter or a limited test report where a company or association recognises the results obtained and endorses the use of materials/application methods.

   

Acrylic 

A synthetic polymer with excellent aging characteristics.

   

Acetate Film

A transparent film which is used for various reasons as a tape backing. Its primary characteristic is that it is more moisture resistant then cellophane.

   

Acrylic Polymer

A synthetic polymer with excellent ageing characteristics that can be used a single component adhesive or a coating or saturate, depending upon circumstances.

   

Adhere

Surfaces that are held together by forces between them are said to adhere.

Adherend

A substrate which is held to another substrate by an adhesive.

   

Adhesion 

The attraction between the surfaces of two materials.

   

Adhesive failure 

Describes the separation of adhesive either from backing or from the substrate. The other basic failure mechanism of an adhesive bond is "cohesive failure" which refers to a fracture in the middle of the bulk adhesive.

   

Adhesion

A bond established upon contact between two surfaces

 

a) Ultimate Adhesion: The maximum bond established between a product and the surface to which it is adhered.  The time required to reach ultimate adhesion varies with the adhesive, but it is usually in the range of 72 - 96 hours.

 

b) Peel Adhesion:  The force required to remove a strip of pressure-sensitive material from a surface at a fixed rate of removal.  Peel adhesion can be measured at 90 degrees or 180 degrees  from the surface.

 

c) Shear Adhesion:  The force required to pull a pressure-sensitive material from a standard flat surface in a direction parallel to the surface to which it has been affixed.  It is usually expressed as the time required for a one square inch sample to slide off a metal panel when pulled by a specific weight.

   

Adhesion build-up

An increase in the adhesion value of an assembly after it has been allowed to dwell.

   

Adhesion to Backing

The resultant bond when one piece of tape is applied to the back of another piece of the same tape.

   

Adhesive Bleed

A condition in which adhesive has oozed out or has been mechanically drawn from under the edge of a pressure-sensitive material through a split in the back of the material or through the edge of sheeted stock

   

Adhesive failure

When an adhesive bond fails due to lack of adhesion to the substrate(s). This is the case when no adhesive residue is found on the substrate after removal of the tape or failure of the adhesive bond

   

Adhesive residue 

Adhesive remaining on the surface when the tape is pulled away

   

Adhesive transfer

When an adhesive tape is removed and the entire adhesive is left on the substrate and nothing is left on the carrier or support. This indicates that the adhesive bond is stronger to the substrate than to the carrier or support.

   

Adhesive Skip

An area without adhesive.

   
   

Ageing resistance

Degree of reliable performance of the tape over time, under certain conditions.

 

Depending on the adhesive system being used, PSA tapes are often usable for permanent applications. This permanence is reflected by the resistance of the adhesive against:

 

• Ozone (O3), Oxygen (O2)

 

• UV light : relevant for transparent substrates such as glass or PC ; under direct exposure, yellowing or discoloration of the adhesive or backing (e.g. window bars).

 

• Temperature

 

• Humidity, water

 

• Different kinds of chemicals

 

Generally acrylic adhesives are much better suited to withstand these environmental influences than rubber adhesives and can maintain their permanent, reliable functionality over many years

   

Air Curing                        

The vulcanization of a rubber product in air as distinguished from vulcanizing in a press or steam vulcanizer.

   

Aluminium Foil

Thin flexible sheets of metal, such as aluminum, copper, and lead, used as tape backings because of their inherent properties such as weather resistance, electrical conductivity, reflectivity, etc

   

Anchorage 

The specific adhesion of a pressure sensitive adhesive to a face material or an anchor coat.

   
   

Aqueous

Containing or water like.

   
   
   

Backing

Materials which "carry" the adhesive. The backing also reinforces the  PSA tape and improves handling and processing properties. Most commonly used backing types are:

 

               1. Film backings (e.g. PET, PP, PVC, PE)

 

               2.Paper based backings (e.g. non-woven, tissue)

 

               3.Foam backings (e.g. PU-, PE- PVC-foams)   A specialty PSA tape type is a transfer PSA tape which has no backing.  The adhesive is directly coated on the liner.

   

Back-grind                       

Distortion at the parting line, usually in the form of a ragged or torn indentation.

   
   

Bleed through

When adhesive is present on the surface of a porous substrate as a result of the adhesive penetrating the substrate from the original bond line.

   

Blocking

An undesired adhesion between touching layers of a material, such as occurs under moderate pressure during storage or use. Normally associated with unwind problems or liner removal.

   

Bobbin

A term used to describe a format of tape where the material is wound onto a spool in narrow widths as a continuous length (sometimes incorporating splices).  Can also be known as spools.

   

Bond line

The adhesive layer in a bonded joint.

   

Breaking force

The force required to bring an adhesive joint to the point of failure.  This applies to all the potential failure modes.

   

Buna N                              

A general term for the copolymers of butadiene and acrylonitrile. Also known as Nitrile.

   

Buna S

A general term for the copolymers of butadiene and styrene. Also known as SBR and GRS.

   

Bursting Strength

The ability of a tape to resist damage when force is applied perpendicularly to the surface of the tape.

   

Butyl 

A synthetic rubber of the polybutene type exhibiting very low permeability to gases.

   

Calender

A machine in which material is pressed between a number of rollers to smooth it.  Generally used for heavy coat weights.

   

Caliper

A thickness measured under specific conditions.

   

Carrier

A carrier is the material that adhesive has been coated upon to produce a tape (also see Backing, Support).

   

Cleavage

The force required to pull apart two rigid substrates.

   

Catalyst

A chemical in small quantities which accelerates a chemical reaction without itself necessarily becoming part of the final product. Cellular Material - A generic term for materials containing many cells (either open, closed, or both) dispersed throughout the mass.

   

Closed side Adhesive

The surface of the adhesive on a double sided tape, which normally remains in contact with the release liner on unwinding.

   

Coated Cloth

Fabric with a rubber or plastic back coating to give increased moisture resistance and longer wear.

   

Cockling

A term to describe the wrinkling of a liner due to water absorption. 

   

Cohesion 

A measure of the internal strength of a material.  For an adhesive this is its resistance to splitting.  Good cohesion is necessary for clean removal.

   

Cohesive failure 

Where the adhesive bond to the substrate and carrier/other substrate, is stronger than the internal strength of the adhesive resulting in the adhesive splitting, leaving residue on both the carrier and substrate.  This type of failure often indicates excessive temperatures, chemical attack, or excessive adhesive thickness.

   

Cold Flow

The tendency of a pressure-sensitive adhesive to act like a heavy, viscous liquid over long periods of time. Such phenomena as oozing and/or increases in adhesion are the results of this characteristic.

   

Conditioning

The process of subjecting material to specific temperatures and relative humidity conditions for a stipulated period of time.

   

Conductive Adhesive

(Electrically) - Adhesive with metal/carbon content providing electrical conductivity.

 

 (Thermally) – Adhesive with characteristics that will allow the transmission of heat

   

Conformability

The ability of an adhesive tape to fit and make contact with an irregular surface without creasing or folding.

   

Core

The inner cylinder of cardboard or plastic on which the tape is wound.

   

Corona treatment 

A surface treatment which improves adhesion by increasing the critical surface tension through the use of an electrical field.

   

Corrosion Inhibitor

When two dissimilar metals are in contact, electrolytic corrosion may occur at the interface.  A corrosion inhibitor (i.e. a tape) can be used as a barrier between the two metals to prevent any chemical interaction.

   

Crazing

 A surface effect on material characterized by multitudinous minute cracks.

   

Creep

The dimensional change with time of a material under stress, which is caused by the initial instantaneous elastic or rapid deformation.  Creep at room temperature is sometimes referred to as Cold Flow.

   

Cross-Linking

The development of a three dimensional structure within an adhesive to improve cohesive strength, temperature oil or solvent resistance.

   

Cupping  

A slight U-shaped deformation of the tape (at right angles to the length) which usually appears after unwind tension is relaxed.

   

Curl

Material that does not lay flat when slit or sheeted.

   

Cuts

The number of rolls slit from a master roll.

   

Cross-linking 

The process of interconnection of polymer chains.  This normally offers improvements in shear resistance, high temperature resistance and oil or solvent resistance.

   

Dead Stretch

The increase of length of a piece of tape after it has been stretched without breaking and allowed to recover.

   

Delamination 

A separation or splitting of the tape from its carrier. (See Adhesive Transfer).

   

Die cut

Material stamped or cut using a tool manufactured to a particular shape.

   

Dielectric Strength 

The voltage that a tape will withstand without passage of the current through it.

   

Differential Adhesive    

Where the adhesion of faced and unfaced sides of double sided tapes differs.

   

Differential Release

A release liner with each surface providing different release characteristics/values.

   

Dimensional stability

Correlates with humidity of liners. Dimensional stability prevents the liner from showing an irregular surface or dimensional change due to absorption of moisture.

 

Dimensionally stable liners are mainly

 

• PE coated paper liners

 

• Film liners

   

Dimensional Stability

The property of a material that enables it to resist length, width, or thickness changes under varying conditions of heat, cold, moisture, or other influences.

   

Dishing

A sideways sliding of the layers in a roll of tape, one over the other, such that the roll looks like a dish or telescope.

   

Doctor blade or Bar

A regulating scraper blade or bar that controls the amount of adhesive dispensed onto the spreading rollers or directly onto the surface/carrier being coated. 

   

Double-sided tape/ Double coated tape

Comprised of a backing material coated with adhesive on both sides. Usually one adhesive layer is covered with a release liner (closed side) in order to wind the PSA tape in roll form. In d/s tape production the backing is often pre-treated with a primer to enable a maximum anchorage between backing and adhesive.

   

Drawdown

Small hand-prepared sample.

   

Dry Edge

A lack of coating on the edge of the web.

   

Durometer

A meter used for measuring the hardness of cellular materials. The Shore 00 scales measures the hardness of sponge .

   

Dynamic shear

A test method which refers to a shock loading in the same plain as the surface with the adhesive bond.

   

Dynamic tensile

A test method which refers to a shock loading perpendicular to the surface with the adhesive bond.

   

Edge Curl

The peeling back of lifting of the outer edge of a tape after application.

   

Edge picking

Negative effect on the unwinding behaviour of a roll of tape. Caused by oozing of soft adhesives.

 

The adhesive flows out at the roll edges so that neighbouring layers of tape stick together. This problem occurs usually with transfer tapes and/or thicker layers of soft adhesives.

Edge Sealer

A material designed to provide additional security and durability after application of a pressure-sensitive product to a substrate.

   

Electrical Strength 

The voltage at which breakdown of the tape occurs under the prescribed conditions of test, divided by the distance apart of the two electrodes between which the voltage is applied.

   

Electrolytic Corrosion factor

A measure of the tape¹s corrosive effect on an electrical conductor, particularly copper. This is particularly important in the selection of tapes for electrical insulation.

   

Elongation 

The distance a tape will stretch lengthways before breaking.

   

EMI/RFI Shielding Tapes

Shielding tapes include copper and aluminium foils, elastomeric materials laminated to polyester or polyimide films. Often used for their conductive and non-conductive properties, shielding and absorbing static charge, grounding, antistatic masking, cushioning and mechanical protections.

   

Emulsion

Adhesive material suspended in water.

   

Ethylene Vinyl Acetate (EVA)

A copolymer of ethylene and vinyl acetate.  Many different grades are manufactured, with the vinyl acetate content varying from 5 to 50 percent by weight.

   

Extended Liner (Dry Edge)

Refers to the liner width extending beyond the actual adhesive tape width, for easy liner removal. Also referred to as finger lift line.

   

Extruded                  

A manufacturing process where material is forced through a nozzle. Lay-flat material works better than skived material.

   

Extrusion

Material, under pressure, which is forced through the opening of a die in order to obtain a desired cross sectional shape.

   

Face material (base material, face stock

Any paper, film, or fabric suitable for making into a pressure-sensitive material.

   

Feathering 

A jagged, irregular point line frequently characterized by small "feathers" of the top-coat projecting into the masked area.

   

Film

Uniform, homogeneous, nonfibrous synthetic webs. Common films used in the tape industry include polyethylene, polypropylene, polyester, PVC, etc.

   

Finger lift 

A product which has a liner that overlaps at an edge allowing easier removal of the liner without touching the adhesive face.

   

Fisheyes 

Small deformations in the adhesive caused by the entrapment of air or surface wetting problems during coating.

   

Flagging

Peeling away from the surface at the end of a length of tape, particularly in a spiral wound application.

   

Flaking

A condition sometimes occurring during removal of masking tape in which flakes or particles of paint flake away from the tape backing.

   

Flame resistant

Materials that are flame resistant will burn when exposed to a naked flame but will not continue to burn when the flame is removed.

   

Flame treatment

Method for modifying the surface of a substrate to provide better anchorage of an adhesive to a non polar backing by flame.

   

Fluting  

Distortion of a roll of tape in which the layers no longer form a circle.

   

Flexibility

The ability of a tape to be bent or flexed freely.

   

Gapping 

Openings between layers of tape within a roll.

   

Gasket

A device used to retain fluids under pressure or seal out foreign matter. Normally refers to a static seal.

   

Gasketing Tape 

Gasket materials include natural & synthetic rubber, thermoplastic rubber, silicone rubber, films, plastic, vinyl, woven/non-woven fabrics, cork/rubber and chipboard and UL & FR materials. Name brands include Neoprene, EPDM, Buna-N, PORON®, and Nomex®, Lexan®, Mylar®, Kapton®

   

Glassine liner 

A strong, hard quality glazed paper with silicone release coating on one or both sides which is good for die cutting.

   

Glass Transition Temperature

The glass transition temperature (TG) is the temperature at which the adhesive becomes brittle. It is important that the application temperature is distinctly above the TG of the adhesive (e.g. resealable bags that are stored in the fridge or freezer as it can prevent a safe reclosure of the bag).

   

Gravure 

A consistent method of applying low coat weights of adhesive.

   

Green Strength               

Uncured adhesion between plied or spliced surfaces.

   

Gloss or Paint

A Shiny finish on a smooth surface such as vinyl.

   

Hand tearability

Property of tapes which allows manual cutting or tearing without the use of additional equipment such as knife, scissors or dispenser. Both liner and backing must be tearable.

   

Hard Adhesive

Term usually used to characterize highly cohesive PSA tapes:

 

Advantages (compared to soft adhesives):

 

o higher holding power

 

o withstands higher sustained loads

 

o good temperature resistance

 

o less edge picking

 

o improved die cuttability

 

Disadvantages:

 

o low initial tack and adhesion; requires higher contact pressure

 

o not suited for rough surfaces

   

Hardness, Shore A   

The Durometer hardness as measured on a Shore "A" gauge. Higher numbers indicate harder material. (Example: 30 Shore is soft and 90 Shore is hard)

   

Heat Resistance

The property of a material that inhibits the occurrence of physical or chemical changes by exposure to high temperatures.

   

Heat Seal Adhesive

Requires heat to produce flow and possibly cure.

   

High-Density Polyethylene (HDPE)

A polyethylene resin/film made from petroleum ranging in density from approximately 0.940  to 0.965 gm//cm3.  It is harder, more opaque plastic able to withstand higher temperatures.  It has an SPI resin code of 2.

   

High Speed Unwind

A term referring to the process of unwinding or dispensing of tapes at a relatively high rate of speed, usually over 15 meters / minute.

   

Holding power

See shear resistance. The ability of a tape to withstand stationary forces (such as weight).

   

Heat resistance

The property of a material that inhibits the occurrence of physical or chemical changes caused by exposure to high temperatures.

   

Hot melt pressure-sensitive adhesive

Types of pressure sensitive adhesive that can be coated without use of solvents or water. Today double sided tapes based on synthetic rubber as well as acrylics are available for hot melt coating.

   

Humidity resistance

Moisture or even humidity can affect the performance of an adhesive. Especially if applied under wet or very humid conditions the adhesive absorbs the humidity, which leads to reduced adhesion performance. This effect occurs especially with water-based acrylics, which should not be used under those conditions. In general a PSA tape is humidity resistant when it resists contact with humid air or even water without negative effects on the adhesion properties. All acrylics have a good humidity resistance. Humidity can damage paper liners and lead to "bubbles" on the surface of the tape. Basically, filmic liners are more dimensionally stable than paper ones.

   

Hydrocolloid

Hydrocolloid adhesives are complex polymeric structures with the combined properties of adhesion and absorbency, making them ideal for wound care applications.

   

Hygroscopic

A tendency of some materials to readily absorb moisture from the atmosphere.

   

Impact Resistance

Also known as shock resistance. The ability of a tape to resist sudden pulls or shocks.

   

Insulation Resistance   

Ability of a tape to resist the flow of electric current across the backing surface.

   

Insulating Tape         

Normally refers to tape used for electrical insulation.

   

Jumbo

These are the manufactured product of machine web size and have a large diameter consisting of many metres in length.  These are then rewound into logs, which can either be despatched to customers or further converted into rolls etc. Can also be referred to as Parent Roll.

   

Key

The bond between the adhesive and the carrier or backing.

   

Key Coat

The key coat is a bonding agent or process used to provide the required bond strength between the adhesive and the tape carrier.

   

Key failure

This is when the adhesive fails to adhere to and removes cleanly from the carrier.

   

Kiss cut 

Used in the production of pads, gaskets etc where the blades are set to cut through the material, leaving the release liner intact.

   
   

Knife over roller

Using a constant pressure head, a liquid material is deposited onto a carrier.  The amount deposited is dependent upon the pressure of the head, the distance between the knife (doctor blade) and the carrier, the viscosity of the liquid and the line speed of the carrier.

 

 
   

Kraft liner

A sulphate wood pulp paper with a silicone release coating on one or both sides.

   

Label Stock

Pressure sensitive materials which are usually printed, frequently die cut, furnished in roll or sheet form with an interleave, and intended for use as labels.

   

Lamination

The combining of two or more materials to function as one.

   

Lap Joint

A joint made by lapping one material over another to provide a mated area that can be joined with an adhesive.

   

Lay Flat (stay flat)                               A material with good non-curling characteristics.

   

Lathe slitting

A process in converting product in a log format into rolls.  This method of slitting allows the versatility of different widths and is used for low volume conversion.

   

Latent Stain

A stain in a surface to which tape has been applied, which does not become noticeable until sometime after the tape is removed, usually after the surface has been exposed to sunlight or heat.

   

Low-Density Polyethylene (LDPE)

A polyethylene resin/film made from petroleum ranging in density from approximately 0.910 - 0.940 g/cm3.  It is weaker than HDPE being relatively soft, with a lower tensile strength and higher resilience.  It has an SPI resin code of 4.

   

Legging

The stringing out of a pressure-sensitive adhesive. May occur during die cutting and stripping.

   

Lexan

General Electric Company's registered trademark for polycarbonate film.

   

Liner

A removable covering usually applied to a tape surface.

   

Liner Release

 Separation of the liner from the pressure sensitive adhesive immediately before it ¡s applied to the substrate.

   

Low tack tape

Used (often incorrectly) to describe a pressure sensitive tape this has low adhesion.

   

Machine Direction

Web Direction) the direction of a base stock parallel to its movement through the coater.

   

Mandrel

A spindle placed inside a core for rewinding or slitting purposes.  The spindle often has an air bladder along its length to hold the core in place.

   

Material Splice

An area where tape has been used to attach two rolls of material (Vinyl, polyester etc.) together to form one continuous web.

   

Master Roll

A full width roll that has finished the primary manufacturing process and is usually untrimmed.

   

Memory

The property of a material that causes it to attempt to return to its original dimensions after being distorted.

   
   

Metalized Film

A plastic film that has been coated on one side with a very thin layer of metal.

   

 

Migration

 

The molecular movement over a long period of time of an ingredient from one surface to another when both are in contact. Migration may occur between tape components and the surface to which applied. Some plastic films (e.g. PVC) contain plasticizers which are apt to migrate into the tape adhesive, causing the adhesive to soften. Other ingredients like foaming, vulcanisation, age-resistant agents used for flexible seals migrate into the tape and can compromise the bond.

   

MIL (.001")

 One thousandth of an inch.

   

Moisture Vapour Transmission

Moisture vapour transmission rate) A measure of the rate of water vapour transmission through a specific material.

   

Monomer

A simple compound which can react to form a polymer.

   

Natural Aging

The change in a material that occurs when it is exposed to normal environmental conditions.

   

Natural Rubber

Component of adhesives, not inherently self-adhesive. Resins, so called "tackifiers" need to be added to achieve self adhesive properties.

   

Non-polar substrates

Critical surfaces to adhere to due to low surface energy. The lower the surface energy the lower the molecular attraction to the adhesive (adhesion). Typical materials are polyolefin’s such as PP and PE, but also PS, EVA and many powder painted surfaces. By surface pre-treatment (e.g. corona treatment) the polarity can be modified to achieve higher surface energy and improved adhesion. Use of primers will also act as adhesion promoters.

   

Non-woven

Paper and polymer fibre based backing material for PSA tapes.

   

Off-Core

A roll of tape in which the layers are in correct alignment, but the tape is displaced sideways on the core.

   

Offcut

 That part o the trim width that is not utilized.  For example, if a customer orders thirteen 4¡¨ cuts out of 54" finished roll, there is a 2" off cut.  (54¡¨ ¡V (13 x 4").

   

Offsetting

The movement of a component of a tape, usually the adhesive, from its backing; this transfer may occur during unwinding of tape, or on removal of the tape from a substrate.

   

Oozing

A "squeezing out" of the adhesive at the edge of the tape, caused by "cold flow" of a soft adhesive.

   

Opacity

The ability of a tape to prevent the transmission of light.

   
   

Open side (Adhesive)

That surface of the adhesive on a double sided tape which is exposed on normal unwinding or separation

   

Openside ( Liner)

Is the surface of a release liner which is exposed on normal unwinding or separation.

   

Outgassing

Amount of chemical ingredients evaporating from adhesives (e. g. monomer residues, solvents, etc.) especially under elevated temperature conditions. Often a concern in the Automotive, Aerospace and Electronics industries, where chemical residues could affect e. g. electric circuits.

   

Overlaminating

Application of a clear film to a label stock for the purpose of protection or to enhance graphic quality.

   

Over-run                    

A quantity of material in excess of the amount ordered. Trade practices permit +/- 10% tolerance for customer over-runs and under-runs.

   

Peaking

Large singular upheavals in the outer layers of a roll of tape.

   

Peel adhesion

The force per unit width required to break the bond between a tape and a surface when peeled back usually at 180 degrees at a standard rate and condition.

   

PE (Polyethylene)

Non-polar substrate; critical material to adhere to, which requires high performance PSA tapes. Corona pre-treatment can increase the surface polarity and therefore the bond to the adhesive. As foamed material PE is also used as backing for PSA foam tapes.

   

PET (Polyester)

Polar substrate, which is easy to adhere to. Often used as backing and liner material of PSA tapes due to excellent mechanical characteristics and high resistance to moisture, solvents, oil and various chemicals.

   

Penetration Resistance

The ability of a tape to resist slow puncture under pressure.

   

Permanent bond 

Holds the substrates indefinitely.

   

Phenolic

Substance created from the reaction of phenol and aldehyde to produce a resin.

   

Piping (tunnelling)

The material fails to adhere to the release paper or film tightly enough and a line of air forms between them, usually starting at one edge and working across the web.

   

Plasticiser

A material incorporated into a resin formulation to increase its flexibility.

   

Plasticiser migration

The movement over a period of time of plasticisers from a PVC substrate to the adhesive causing it to soften.

   

Plasticizer resistance

The ability of a PSA tape to maintain its properties under influence of plasticizers. In contact with plasticizers (e. g. a component of foam materials or Soft-PVC) the adhesive performance of PSA tapes can be affected, especially with rubber based adhesives. PSA tapes with a film backing sometimes perform better since the film layer acts as a barrier against migration of plasticizers. Important for applications on EPDM or soft-PVC profiles for instance.

   

Plastisol

A liquid consisting of polymer blends, pigments, additives etc.

   

Polar substrate

Uncritical surfaces to adhere to due to high surface energy. On these substrates the high molecular attraction between adhesive and substrate leads to increased adhesion. Most common materials are PET, PC, PVC, ABS, steel, aluminium, glass etc.

   

Polyamide (PA) 

Otherwise known as Nylon, is a thermoplastic which has high strength and is very resistant to wear and abrasion.  It also has good puncture resistance, heat resistance, and low gas permeability.

   

Polycarbonate

A high-clarity film combining the versatility of acetate with the durability of polyester.  It is intended for interior use and may be used in many applications previously processed with polyester or similar films.

   

Polycoated liner

Kraft paper coated with polyethylene to increase moisture resistance, then coated on one side or both with a silicone release coating. These liners have a lower temperature resistance.

   

Polyester (PET) 

A strong film having good resistance to moisture, solvents, oils, and many other chemicals.  It is usually transparent, although it is available with a metallised finish.

   

Polyethylene

A tough, stretchy plastic film having very good low temperature characteristics.  Often used for producing semi-rigid bottles.

   

Polymer

A substance with molecules consisting of one or more structural units repeated any number of times.

   

PP (Polypropylene)

Non-polar substrate (similar to Polyethylene), critical material to adhere to, which requires high performance PSA tapes. Corona treatment can increase the surface polarity and therefore the bond with the adhesive. As foamed material PE is also used as backing for PSA foam tapes.

   

Polyurethane (PU) Foam - Closed Cell

Closed cell foam with adhesive on two sides, used in permanent bonding applications to replace mechanical fasteners, epoxies and screws. Applications include vibration and sound dampening, dust sealing, gasketing, bonding and mounting and used in fenestration, electronics, transportation, sporting goods, etc.

   

Polyurethane (PU) Foam - Open cell

Polyurethane (PU) Foam may also comprise a high open cell content and tends to be coated or adhesive laminated on one side only. Typically these products are used as draught seal or basic NVH (noise vibration, harshness) gap filling material.

   

Pressure sensitive

A term used to describe an adhesive tape which in dry (solvent free) form is aggressive and permanently tacky at room temperature when applied using light pressure to the substrate.

   

Primer

A coating applied to a surface to improve the adhesive bond.

   

Printed Tapes

Printed tape carries a message such as handling instruction, identifying products, promoting a message. Flexographic printing is available in single or multiple colours on materials including plain, single coated or double coated paper, film, foil, foam & cloth. Applications are in the paper, packaging, labelling transportation, surface protection, medical, personal care, computer, plastics, construction & electronics markets.

   

Porosity

The surface density of a substrate.  The property of adhesive absorption by the substrate.

   

Primer

A coating applied to a surface, prior to application of an adhesive to improve the performance of the bond.

   

PTFE / Polytetrafluorethylene

PTFE is known for exceptional resistance to high temperatures, chemical reaction, corrosion and stress-cracking. DuPont™ Teflon® is the registered trademark name for polytetrafluorethylene -

   

PVC

Polar substrate which is easy to adhere to. Often used as a backing available in varying degrees of hardness. Suitable for electrical insulation applications and cable harnessing applications.

   

Reclosable Fasteners 

3M Scotch® brand Reclosable Fasteners can attach firmly in place, but provide multiple openings and closings. Having super strong adhesion, they are ideal for indoor or outdoor use, Other hook and loop fasteners include 3M Dual Lock®, Scotchmate®, Velcro USA® and Back to Back.

   

Release

The force required to remove the release liner from the stock at a specified speed angle.

   

Release coating

Coatings are applied to a liner to allow ease of unwind and prevent delamination or tearing.  This can also be used directly on a carrier/backing as well.

   

Release Force

The measure of the force required to separate a unit width of pressure sensitive tape from a release coated surface at a controlled angle and speed.

   

Release liner

A sheet of paper/polyethylene etc acting as a protector and/or a carrier for an adhesive film or adhesive mass, which is easily removed, generally due to silicone release coating.

   

Removability 

Ability to remove the tape from the substrate without damaging or contaminating the substrate under specified conditions, usually after a long period of time.

   

Removable Adhesive

A pressure-sensitive adhesive characterized by low ultimate adhesion and clean removability from a wide variety of surfaces.

   

Removable bond

Low to moderate adhesion that can then usually be de-bonded cleanly with no adhesive residue.

   

Repulpable

Paper tapes that can be recycled to the process without contamination of the broke pulp.

   

Residue

Adhesive left on the substrate after removal.

   

Reverse wound

A roll of material where the adhesive is exposed on the outer wrap not the liner.

   

Reversion

A deterioration of physical properties that may occur after air aging at elevated temperatures, evidenced by a decrease in hardness and tensile strength, and an increase in elongation; Natural rubber, butyl, polysulfide and epichlorohydrin polymers exhibit this effect (extreme reversion may result in tackiness). Most other polymers will harden and suffer loss of elongation on hot air aging.

   

Rewind slitting

A process to convert into slit rolls by unwinding a jumbo or log, slitting with knifes and then winding onto individual cores.  Normally used for high volume production due to set up time.

   

RoHS (Restriction of Hazardous Substances)

A European Directive (2002/95/EC) which restricts the use of specific heavy metals and flame retardants in electrical and electronic equipment.

   

Rope Stock

A smooth paper made wholly or largely of hemp fibre for tensile strength.

   

Rubber (natural)

A tough elastic substance made from the latex of rubber trees and shrubs.

   

Rubber (synthetic)

A tough elastic substance made from synthetic materials and polymers.

   

Rubber based Adhesive    

A pressure-sensitive adhesive based on natural or synthetic rubber.

   

Saturation (impregnation)

Adding materials (saturant) to the backing for improvement of physical properties and resistance to various deleterious environments.

   

Self-Seal

An adhesive joint that is accomplished by coating both adherend surfaces, and bringing them under pressure; an elastomeric adhesive (cohesive) used on envelope flaps, box closures, etc, whereby the adhesive film will bond only to itself.

   

Service Temperature

The extremes of temperature at which a material can be used without compromising its strength or other properties.

   

Shear 

Loading forces across the face of an adhesive joint.

   

Shear adhesion

The ability of a tape to resist the static forces applied in the same plane as the backing.

   

Shear resistance

Shear resistance is measured as a force required to pull the pressure sensitive material parallel to the surface to which it was affixed under specific conditions. The shear resistance of PSA´s may be measured statically or dynamically. Static shear test methods use a constant load of longer test times. Dynamic shear tests measure the cohesion of the sample in a tensile tester under increasing load (force).

   

Shear Strength

The internal or cohesive strength of the adhesive.

   

Shelf Life

The period of time during which a product can be stored under specified conditions and still remain suitable for use.

   

Shock resistance

Shock resistance is a suddenly applied force on an adhesive bond. Under normal conditions (room temperature) the shock resistance of tapes is significantly higher. PSA tapes with a foam backing have an incorporated buffer system and therefore absorb shock much better than film tapes. Additionally high coating weights and flexible backings of high quality film can take over part of this buffer function.

 

Test method: metal plates with double sided tapes are laminated to a metal board. A shock impact is given on the back of the board

   

Shore hardness

A measurement of surface hardness of a material using a Durometer.  Scapa uses the 'OO' scale for foam products. The more common 'A' scale is used for hard rubber materials.

   

Silicone

A unique polymer system that can be a very effective release coating, or pressure sensitive adhesive capable of functioning at extreme temperature.

   

Silvering

Defect in which the tape tears or breaks into small pieces during unwind or removal from the application surface.

   

Single Sided

The adhesive is applied to one surface of the backing only.

   

Solution

The dissolving of a solid into a liquid by mixture with a solvent.

   

Solvent

A dissolving, thinning, or reducing agent.  Specifically, a solvent is a liquid that dissolves another substance.

   

Solvent Adhesive

An adhesive component that is dissolved in an organic solvent for coating.  Rubber or acrylic based systems can be coated this way.

   

Solvent resistance

The resistance of a pressure-sensitive adhesive to the destructive action of specific organic liquids.

   

Specific Adhesion

The relative tendency of an adhesive to form a bond on a specific surface. For example, some adhesives may be permanent on one surface and removable from another.

   

SPI Resin Codes

The SPI resin identification coding system was developed by the Society of Plastics Industry (SPI) in 1988.  It is a set of symbols ranging from 1 to 7 placed on plastics to identify the different polymer types and allow efficient separation for recycling.  It has since been used internationally.

   

Splice

During conversion or manufacturing webs are joined by overlapping with a double-sided tape/transfer tape or by butting the ends together with a single sided tape.

   

Spool (Traverse) Wound Rolls

One layer of tape starts on a side of the core. The next layer overlaps with the first one and then the tape is wound back and forth traversing from one side of the core to the other. This process allows for much longer rolls (up to 33,000yds depending on the width and thickness of product) thus reducing the downtime involved with constant roll changes.

   

Stabailise

To increase the steadiness of a film and keep it from changing or fluctuating.  Usually laminating polyester to one or both sides of the vinyl stabilizes vinyl films.

   

Static shear

A measure of a product's internal or cohesive strength.

   

Substrate

The surface(s) that the adhesive tape is applied to.

   

Substrate failure

When an assembly fails and the weak link is the strength of the substrate.

   

Support

A term used to describe the material used in the middle of a double-coated tape. (See Carrier)

   

Surface Energy

The measure of surface tension in dynes. The lower the surface energy of a substrate, the more difficult it becomes for an adhesive or coating to wet out that surface. Low Surface Energy LSE materials resist adhesive spread over the substrate while High Surface Energy HSE materials allow excellent spread and provide the best adhesion.

   

Surface Treating

Any method of treating a polyolefin so as to alter the surface and render it receptive to inks, paints, lacquers, and adhesives such as chemical, flame, and electronic oxidation.

   

Synthetic

Made by chemical synthesis especially to imitate a natural product (e.g. synthetic rubber).

   

Tack 

The condition of the adhesive when it feels sticky and offers an initial 'grab' immediately upon contact with little pressure.  Not to be confused with ultimate or peel adhesion.

   

Tear resistance

The ability of a tape to resist tearing after a tear has been started by cutting or nicking the edge.

   

Telescoping

A sideways sliding of the tape layers, one over the other, such that the roll looks like a funnel or telescope.

   

Tensile strength

The force required to break a piece of tape by pulling on opposite ends of the tape.

   

Thermoplastic

Becoming softer on heat application and hardened by cooling even after repeated cycles.

   

Thermosetting

A material that will undergo a chemical reaction by the action of heat, catalyst, ultraviolet light etc leading to a relatively infusible state.

   
   

Tight Release

The adhesive does not release from liner freely.

   

Transfer adhesive

This adhesive tape is solely adhesive and has no carrier only a release liner.  When reverse wound it can be dispensed using a hand held dispenser gun. ATS (adhesive transfer system)

   
   

Transparency            

The ability of a tape to allow transmission of light. A tape is rated as transparent if 10 point type can be read easily when the tape is applied directly over it.

   

Transverse Direction (Cross direction)

The direction of a substrate from left to right and from side to side as opposed to the web direction (90 degrees to the machine direction.

   

Twisting

When a tape has been unwound from the roll and allowed to hang freely, the tendency of the tape to curl around lengthwise.

   

Ultimate adhesion

The maximum adhesion available determined by the force required to remove a length of tape from a surface after an extended period of time.

   
   

Unwind adhesion

The force required to remove the tape from the roll.

   

U.V. (Ultraviolet Light)

That part of the spectrum wherein the wavelength of light is shorter) than that of visible light.

   

U.V. Curing

A system that uses ultraviolet rays to facilitate the curing process.

   

U.V. Resistance

The ability of any material to withstand extended exposure to U.V. light without degradation, hardening, or excessive discoloration.

   

Unwinding force

Force required unwinding a d/s PSA tape. The unwinding force is a result of the interaction between adhesive and release liner. A low and constant unwinding force is an important property for the processing of an adhesive tape.

   

Vinyl

A synthetic plastic that can be made in film, sheet, or other forms and can be manufactured in rigid or flexible constructions. They are generally more flexible and formable than polyesters.  Also known as PVC or polyvinyl chloride.

   

Viscosity

The flow rate of an adhesive.

   

Void

An area of an adhesive-coated substrate that does not have the coating.

   

Vulcanisation

The treatment of rubbers etc with sulphur at a high temperature to increase its strength by promoting cross-linking.

   

Water Absorption

The measure of the amount of water which will be soaked up by the tape and retained

   

Water vapour

 

Transmission

The amount of water vapour measured passing through a tape within a specified time.

   

Weather Resistance

The ability of a material (tape or adhesive) after application to resist exposure to such conditions as light (daylight, UV-light) and humidity. Generally acrylic adhesive tapes display good weathering resistance.

   

Weaving

A poorly wound roll of tape in which the individual layers of tape are not in alignment with the other layers.

   

Web

A large wide and long roll of material usually used in a continuous manufacturing process (usually the carrier or liner)

   

Wet Tensile               

Tensile strength of tape that has been kept wet for a specified period of time. Measures ability of tape to function satisfactory when exposed to moisture.

   

Wetting

The ability of an adhesive to flow uniformly over the laminated surface to which it is bonded.

   

Wet Out                        

 The ability of an adhesive to spread, thereby filling in the hills and valleys of the substrate.

   

Yellowing

A gradual change in the original appearance of a material characterized by the development of yellow and brown hues.