Pressure Sensitive Adhesive Glossary of Terms

A

Abrasion Resistance

The ability of a tape to withstand rubbing and still function.

Acrylic

A synthetic polymer with excellent aging characteristics that can be used as either a single component adhesive or a coating or saturate, depending upon composition.

Adhesion

A bond produced between a pressure sensitive adhesive and a surface.

Adhesive

Any material that will usefully hold two or more objects together solely by intimate surface contact.

Adhesive transfer

The transfer of adhesive from its normal position on the tape to the surface to which the tape was attached, either during unwind or removal.

Anchorage

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

B

Backing (Carrier)

A relatively thin flexible material to which the adhesive is applied. Theoretically, any material that is reasonably flat, relatively thin, and flexible could be used as a tape backing.

Backscoring (Crack & Peel)

Cutting the bottom release liner in such a way as to aid in the dispensing or applying of the product.

Backsplit (scoring liner)

Slits in the release liner to facilitate easy removal by hand.

Baloney (Cevi, Lathe or Lever) Slitting

Standard length log rolls cut through both tape and core roll after roll. Allows for quicker change-over and smaller quantities than rewind slitting.

Bi-Directional

Related to strapping tapes, in which the reinforcing material consists of filaments in both the length and the cross directions, usually a woven cloth.

Bleeding

Penetration through the tape of a coloring liquid (paint, etc.) onto the surface to which the tape is applied.

Bursting Strength

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

Butt-cut

A conversion process where a die creates individual pieces by cutting through the laminated material and adhesive — no waste area between adjoining pieces.

Butt-splice

A splice made by joining tape end to end without overlapping. The splice is assembled by a thin single-coated tape centered on both sides.

C

Caliper

A measurement of thickness expressed in thousandths of an inch (English units) or millimeters (metric units).

Carrier

Sometimes used to refer to the backing material, particularly in double-faced tapes.

Coating Weight

The weight of a coating per unit area.

Cohesion (cohesive strength, internal bond)

The ability of the adhesive to resist splitting. Good cohesion is necessary for clean removal.

Converter (Fabricator)

One who modifies products to enhance value and final usage — laminating, die-cutting to custom shape, precision slitting, adding/removing liners, and cutting pieces to length.

Creep

A slow movement of the adhesive or backing under stress.

Creped

Paper that has small "folds" in it, giving it high stretch.

Cross-Linked (Cured)

The development of a three-dimensional structure in an adhesive, normally activated by heat. Improves shear, high-temperature, and oil/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.

Cross direction tensile

Tensile strength measured at right angles to the length.

D

Delamination

A separation of the backing into two distinct layers, between laminations of a multi-backing tape, or between filaments and backing of a filament-reinforced tape.

Die-cut

The thin line of severance between a pressure sensitive tape or label and its matrix made by the cutting edge of a die.

Die-cutting

Process by which any shape, pattern or design can be cut out of various pressure-sensitive tapes using custom-made dies.

Double Coated Tape

A pressure-sensitive tape consisting of a carrier with adhesive coated on both sides (typically, a liner is necessary to unwind the roll).

Dry Edge

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

E

Edge Curl

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

Elastomer

An elastic, polymeric substance, such as natural or synthetic rubber.

Extended Liner (Dry Edge)

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

F

Face side

The unlined side of a double-coated tape.

Feathering

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

Filaments

Longitudinal "threads" of glass, polyester, nylon, or other high-strength materials.

Film

Uniform, homogeneous, nonfibrous synthetic webs.

Flagged Rolls

Used to identify a bad spot in the roll for internal processing (or a splice).

Flagging

A peeling away from the surface of the end of a length of tape, particularly in a spiral-wrap application.

Flame Resistance

The ability of a tape to withstand exposure to flame. Fireproof materials will not burn even when exposed to flame; flame-resistant materials will burn when exposed but not continue once removed.

Flatback

Smooth paper backing.

Fluorocarbon Films

A film with very high and low temperature limits, excellent electrical characteristics, and a very slippery, non-sticking surface. One example is DuPont's Teflon (PTFE).

Fluting

Distortion of a roll of tape such that layers no longer form a circle.

Foam

A soft, cushiony material formed by creating bubbles in base materials such as natural or synthetic rubbers, or other elastomeric materials.

G

Gapping

Opening between layers of tape within a roll.

Ghosting

A haze-like deposit of adhesive left by a tape after its removal.

Gloss

A light reflection characteristic of tape backings, usually expressed by terms like glossy, low gloss, matte.

H

High-speed Unwind

Unwinding or dispensing of tapes at a relatively high rate of speed, usually more than 50 feet per minute.

Hot Melt (pressure sensitive adhesive)

A pressure-sensitive adhesive applied to the backing in a hot molten form that cools to form a conventional PSA.

Holding Power (Shear Adhesion)

The ability of a tape to resist static forces applied in the same plane as the backing. Usually expressed in the time required for a given weight to cause a given amount of tape to come loose from a vertical panel.

I

Impact Resistance

The ability of a tape to resist sudden impacts, pulls, or shocks as may be encountered by packages in transit.

Individual Pieces

Each die-cut piece is individual, not on a roll.

Insulating Tape

Normally refers to tape used for electrical insulation.

Insulation Resistance

The ability of tape to prevent the flow of electrical current across its surface, usually measured on the backing.

K

Kiss-cutting

Die-cutting process by which only the actual usable part remains on the liner; all waste (matrix) around the die-cuts is removed.

Kraft

A sulfate wood pulp paper.

L

Label Stock

Pressure-sensitive materials, usually printed, frequently die-cut, furnished in roll or sheet form with a liner, intended for use as labels.

Laminating

Joining of several layers of varying materials utilizing pressure-sensitive tapes.

Lap splice

A splice made by overlapping the ends.

Lifting

A section of tape has pulled away from the surface to which it has been applied.

Liner Side

In roll form, the side of the roll protected by the liner.

M

Master Roll

A roll of tape as wide as 74", wound in a predetermined length of 250 yds or more.

Matrix

Scrap material left after a die cuts a pattern. Usually removed and discarded.

Metal Foil

Thin, flexible sheets of metal (aluminum, lead, etc.) used as tape backings for weather resistance, reflectivity, etc.

Migration

The movement, over long periods of time, of an ingredient from one component to another when the two are in surface contact. Some plastic films contain plasticizers apt to migrate into the tape adhesive, softening it.

Mils

Used in describing adhesive coat weights or thickness. The term means thousandths of an inch.

Machine direction tensile

Tensile strength measured parallel to the length of the tape. Default direction unless otherwise specified.

N

Non-Oriented

A material that has yet to be stretched or expanded to its maximum size.

O

Off-Core

Layers of tape are in correct alignment, but tape is displaced sideways on the core.

Offsetting

When a printed tape is unwound and some of the printing ink is picked off by the adhesive or migrates into it — effectively a delamination of the ink.

Oozing

A "squeezing out" of the adhesive from under the backing. Edges of a roll become tacky.

Out-Gassing

The release of volatile components under heat or vacuum.

Over-run

A quantity of material in excess of the amount ordered. Trade practices permit ±10% tolerance.

P

Pancake-wound rolls

Most typical supply form for pressure-sensitive tapes. Each layer of tape is directly on top of the last (with or without a liner).

Pattern coating

Width and spacing arrangement of adhesive laid down parallel to machine direction, across the width of pressure-sensitive stock during manufacturing.

Peaking

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

Plain cloth

Fabric woven from cotton, glass, or other fibers without further treatment.

Polyethylene (PE)

A tough, stretchy film with very good low-temperature characteristics.

Polyester

A strong film having good resistance to moisture, solvents, oils, caustics, and many other chemicals. Usually transparent.

Polypropylene (PP)

A cousin of polyethylene with generally similar properties, but stronger and with higher temperature resistance.

Polyurethane Foam

Closed-cell foam with adhesive on two sides, used in permanent bonding applications to replace mechanical fasteners, epoxies and screws.

Perforating

Hole-punching the release liner, usually between kiss-cut parts.

Pressure Sensitive

A category of adhesives that, in dry (solvent-free) form, are aggressively and permanently tacky at room temperature and firmly adhere to many surfaces upon mere contact without needing activation by water, solvent, or heat.

Pressure Sensitive Tape

A combination of a pressure sensitive adhesive and a backing.

Primer

Used to increase the bond of the adhesive to the backing. Assists in keeping the adhesive on the backing when a tape is removed.

Printability

The ability of a tape to accept and hold a printed legend and to resist offset of the printing when rewound into a roll.

Puckers

A distortion associated with laminated constructions, appearing as ripples on the surface — separation of the two laminated components, generally in the cross-machine direction.

R

Reinforcements

A material added to a tape to provide additional strength.

Release

The adhesion level between a release liner and the adhesive/carrier combination. High release means the liner is more difficult to remove; low release means it removes easily.

Release Coating (easy unwind treatment)

A coating applied to the backing on the side opposite the adhesive that provides ease of unwind and prevents delamination or tearing.

Release Coat Transfer (Silicone Transfer)

Particles of the release coat stick to the adhesive on unwind; the resulting tape will have little or no ability to stick.

Release Liner

Siliconized paper or film coated on one or both sides that protects the adhesive until use. Removed and discarded before application.

Rewind Slitting

Preferred method for slitting large volumes of standard-sized rolls of pressure-sensitive tape. Master rolls or jumbos are used to unwind tape and then rewound layer over layer across a set of pre-spaced cores.

S

Saturation (impregnation)

Adding material (saturant) to the backing to improve physical properties and resistance to environmental factors.

Self-Wound Roll

A roll of tape in which each layer is directly on top of the last. No liner.

Shear Strength

The resistance of an adhesive film to splitting when a load is applied along the plane.

Shelf Life

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

Silicone

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

Silicone Adhesive

Adhesive system designed for sticking to silicone surfaces (e.g. splicing liners).

Single Coated Tape

A pressure-sensitive tape consisting of a carrier with adhesive coated on only one side.

Single Faced

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

Slip Sheet or Interliner

A treated sheet used to cover the adhesive to facilitate handling.

Specification

A document that spells out the requirements for a particular tape or group of tapes. Details physical properties, performance, composition, sampling, and packing characteristics.

Splice

A point at which two separate lengths of tape are joined together.

Spool (Traverse) Wound Rolls

One layer of tape starts on a side of the core; the next layer overlaps with the first; the tape is wound back and forth traversing from one side of the core to the other. Allows for much longer rolls (up to 33,000 yds).

Substrate

The backing to which a pressure-sensitive adhesive is applied.

T

Tacky

The condition of the adhesive when it feels sticky or highly adhesive.

Tearing

Breaking or slivering of a tape during unwind.

Tear Resistance

The ability of a tape to resist tearing after a tear has been started by cutting or nicking of 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 (break strength)

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

Thickness

Distance from one surface of a tape, backing, or adhesive to the other — usually expressed in mils or thousandths of an inch.

Tissue

Typically referred to as a carrier in a double-coated product. A tissue carrier makes slitting and die-cutting easier by preventing adhesive flow, and allows some elongation and conformability.

Tolerance

Maximum allowable variation from agreed-upon or specified dimension.

Transfer Tape

An unsupported pressure-sensitive adhesive tape.

U

Uniformity

The consistency of a single type of tape — within a roll, roll-to-roll, or lot-to-lot.

Un-Plasticized Vinyl (UPVC)

A tough durable plastic film, differing from PVC principally in that UPVC is not very stretchy.

Unwind or Unwind Adhesion

The force required to remove tape from the roll.

V

Vinyl or Plasticized Polyvinyl Chloride (PVC)

A tough, durable plastic film with excellent resistance to oils, chemicals, and many solvents. Excellent abrasion resistance. High stretch due to plasticizer.

Vinyl Nitrile Sponge Rubber

Closed cell, adhesive one side. Offers good oil resistance and shock absorbency.

Void

A bare uncoated area on either the adhesive or release-coated side of the tape.

W

Wet tensile

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

Water Penetration Rate

The weight of water transmitted through a controlled area of tape under a specified time and conditions.

Weaving

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