Glossary of Terms

* Provided courtesy of the Pressure Sensitive Tape Council.

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

ACCELERATED AGING
A means whereby the deterioration of a tape encountered in natural aging may be accelerated and reproduced in the laboratory.

ACCELERATED WEATHERING (weathering)
Exposure in a chamber to ultraviolet light, heat, and water whereby the effect of outdoor exposure on a tape can be approximated.

ADHESION TO BACKING
The bond produced to the backing of the same tape or another tape backing.

ADHESIVE DEPOSIT OR RESIDUE
Adhesive that is pulled away from the tape upon removal and remains on the surface to which it has been applied.

ADHESIVE TRANSFER
The conveyance of adhesive from its normal position on the tape backing to a 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.

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

BACKSIZE
An occlusive coating applied to the non-pressure sensitive side of a porous backing such as paper in order to provide a satisfactory surface that the pressure sensitive adhesive side can contact when the tape is wound into a roll.

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

BLOCKING
Adhesion between the sheets of the plies of rolls of coated material, usually due to extreme conditions of pressure, temperature, or humidity.

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

CALIPER
The thickness (as of a sheet of paper) measured under specified conditions. See also THICKNESS.

CARRIER
A webstock that holds a pressure sensitive adhesive, especially used to refer to double-faced or double-coated tapes.

COATING WEIGHT
The weight of a coating per unit area. In SI-units expressed as grams per square meter (g/m2).

COHESION (cohesive strength, internal bond)
The ability of the adhesive to resist shear stress and splitting. Good cohesion is necessary for clean removal.

COLD FLOW
The tendency of a pressure sensitive adhesive to act as a heavy viscous liquid over long periods of time. Such phenomena as oozing and increase in adhesion with time are the result of this characteristic.

COLOR STABILITY
The ability of a tape to retain its original color, particularly when exposed to light.

CORONA RESISTANCE
The ability of an elastomeric adhesive, coating, or sealer acting as an insulator to withstand the effects of high voltage discharge. Indications of failure appear as surface cracks.

CREEP
The slow movement of the adhesive or backing under shear stress.

CROSS-LINKING
Developing a three-dimensional molecular structure in an adhesive normally activated by heat or irradiation. An improvement in shear resistance, high temperature resistance, and oil or solvent resistance will normally result.

CURE
To alter the properties of an adhesive by chemical reaction, which may be condensation, polymerization, or vulcanization. Usually accomplished by the action of heat and catalysts, alone or in combination, with or without pressure.

CURL
The tendency of paper by itself or in a laminate to bend or partly wrap around the axis of one of its dimensions.

DELAMINATION
A separation or splitting of the tape such as separation of the backing into two distinct layers, separation between laminations of a tape consisting of more than one backing, separation between filaments and backing of a filament reinforced tape, or separation of the adhesive from the backing.

DIELECTRIC STRENGTH
The measure of the maximum voltage stress that a single layer of tape can withstand before dielectric failure occurs, the test being carried out under prescribed conditions.

DIMENSIONAL STABILITY
That property of a material that relates to the constancy of its dimensions, particularly in relation to external influences such as moisture or temperature.

DOUBLE COATED
An adhesive application to both sides of a backing.

EDGE CURL
The peeling back or lifting of the outer edge of an applied tape in a curved manner.

EDGE LIFT
The tendency for the edge of an adhesive label to lift from a surface to which it has been adhered.

ELASTICITY
The extensible property of adhesive films or adhesive interfaces to contract and expand in such a manner as to overcome the differential contraction and expansion rates that the bonded adherends may exhibit.

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

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 (stretch, ultimate elongation)
The distance a tape will stretch in the machine or cross direction before breaking under controlled conditions, expressed as a percentage of original length. Elongation is not necessarily an indication of conformability.

FACE STOCK
Any paper, film, fabric, laminate, or foil material suitable for converting into pressure sensitive material stock. In the finished construction this web is bonded to the adhesive layer and becomes the functional part of the tape construction.

FALL-OFF
When a tape pulls completely from the surface to which it is applied and drops off.

FATIGUE
A weakness resulting from stress created by repeated flexing or impact force upon the adhesive-adherend interface.

FILAMENTS
Thin, longitudinal yarns or threads of glass, polyester, nylon, or other high strength materials.

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

FLAME RESISTANCE
The ability of a tape to withstand exposure to flame. Fireproof materials will not burn even when exposed to flame. Flame-resistant (fire-retardant, self-extinguishing) materials will burn when exposed to flame, but will not sustain the burn after the flame is removed.

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

GAPPING
Openings between layers of tape within a finished roll.

GLOSS
A light reflection characteristic of tape backings, usually expressed by such terms as glossy, low gloss, matte, etc.

HEAT SEAL
An adhesive film intended to be reactivated by the application of physical or chemical changes caused by exposure to high temperatures.

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 (shear adhesion, shear resistance)
The ability of a tape to resist static forces applied in the same plane as the backing. Usually expressed in a time required for a given weight and length of tape to shear free from a vertical panel.

HOT MELT (pressure sensitive adhesive)
A pressure sensitive adhesive, applied to the backing in hot liquid form, which then cools to form a conventional pressure sensitive adhesive.

HUMIDITY
The moisture content of the air. Actual humidity is the number of grams of moisture in the air at any given time. Relative humidity is the percent of moisture relative to the maximum that air at any given temperature can retain without precipitation.

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

IMPACT RESISTANCE (shock resistance)
The ability of a tape to resist sudden impacts, pulls, or shocks as may sometimes be encountered by packages in transit.

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

LABEL STOCK
Pressure sensitive insulation. materials furnished in roll or sheet form with liner, which can be later printed, frequently die cut, and intended for use as labels.

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

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

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

METAL 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.

MOISTURE VAPOR TRANSMISSION RATE
A measure of the rate of water vapor transmission through a pressure sensitive product usually measured in grams / square meter / 24 hours.

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

OOZING
A “squeezing out” of the adhesive from under the backing. Occurrence when a tape is in a roll form causes the edges of the roll to become tacky.

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

OUT-GASSING
The release of volatile components under heat or vacuum.

PATTERN COATED
A term that refers to the width and spacing arrangement of strips of adhesive laid down parallel to machine direction and across the width of pressure sensitive stock during its production.

PEEL ADHESION
The force per unit width required to break the bond between a pressure sensitive adhesive tape and the surface to which it has been applied when the tape is peeled back at a controlled angle at a standard rate and condition.

PLASTICIZATION
The softening of an adhesive when exposed to migrating plasticizers or oils.

PRESSURE SENSITIVE
A term commonly used to designate a distinct category of adhesive tapes and adhesives which in dry form (solvent / water free) are aggressively and permanently tacky at room temperature and that firmly adhere to a variety of dissimilar surfaces upon mere contact without the need of more than finger or hand pressure. These products require no activation by water, solvent, or heat in order to exert a strong adhesive holding force toward such materials as paper, plastic, glass, wood, cement, and metal. They have sufficient cohesive holding power and elastic nature so that, despite their aggressive tackiness, they can be handled with the fingers and removed from smooth surfaces without leaving a residue.

PRIMING
Application of a thin layer of adhesive-like material to a backing that serves as a bonding agent between the backing and the final adhesive coat.

QUICK STICK (finger tack, initial adhesion, wet grab)
see TACK.

RELEASE LINE05/03/2010 9:48h covers the adhesive side of the tape. It is removed prior to application. Most frequently found on double- sided tapes and label stocks.

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.

REWINDING
The operation of winding the webstock from the reel onto a core to produce rolls of the desired width, diameter, and tension.

ROPE STOCK
A smooth paper made wholly or largely of hemp fiber for tensile strength.

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.

SHEAR STRENGTH AFTER SOLVENT IMMERSION
The force required to separate a bond by shear force after immersion in a typical varnish solvent under designated conditions.

SINGLE FACED
A tape to which a pressure sensitive adhesive is applied to only one side of the backing.

SLIP SHEET OR INTERLINER
See RELEASE LINER.

SLIVERING
When the tape tears or breaks into small pieces, either on unwind or on removal from a surface.

SUBSEQUENT ADHESION
The force required to remove a unit width of pressure sensitive tape from a standard panel after it has been in contact with a release liner for a given period of time. This must be compared with the adhesion of the same tape that has not been in contact with the release liner to determine the degree of loss of adhesion.

SURFACE ENERGY (surface wetting ability)
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.

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.

TACK
The property of a pressure sensitive adhesive that allows it to adhere to a surface under very slight pressure. It is determined by the ability of the adhesive to wet quickly the surface it contacts.

TEAR RESISTANCE
The force required to propagate a tear in a tape in a given direction after the tear has been initiated.

TELESCOPING
A sideways sliding of the tape layers, one over another, such that the roll looks like a funnel or a telescope, usually occurring over a period of time.

TENSILE STRENGTH (breaking strength)
The force required to break a unit width of tape by controlled pulling on opposite ends of the piece.

THICKNESS (caliper, gauge)
The perpendicular distance from one surface of either a tape, backing, or adhesive to the other, usually expressed in mils, thousandths of an inch, or millimeters. This is usually measured under controlled slight pressure with a special gauge.

TRANSFER TAPE
A pressure sensitive adhesive unsupported applied to a two-side release coated liner.

UNWIND or UNWIND ADHESION
The force required to remove tape from a roll under prescribed conditions.

WATER PENETRATION RATE (WPR)
The weight of water transmitted through a controlled area of tape under a specified time and conditions.

WATER VAPOR TRANSMISSION (WVTR)
The weight of water vapor allowed through a controlled area of tape within a specified time period and under controlled conditions.