Glossary of Terms

Adhesion - Adhesion is the interaction that develops between two dissimilar bodies when they are in contact. At the molecular level, adhesion is based on physical and in some cases chemical bonding. The strength of adhesion depends on the type of adhesive.

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

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:

Film backings (e.g. PET, PP, PVC, PE)
Paper based backings (e.g. non-woven, tissue)
Foam backings (e.g. PU-, PE- PVC-foams)

Cohesion - Cohesion describes the inner strength of the adhesive. It mainly determines the holding power (shear resistance) of the tape.

Conformability - The backing of a PSA tape influences its ability to adhere to curved, rough or irregular surfaces.

Edge picking - Negative effect on the unwinding behavior of a roll of tape. Caused by oozing of soft adhesives.

Fish eyes - Optical effect caused by entrapment of air between different tape layers on a roll.

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

Hand tearable - 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.

Liner - Anti-adhesive material which covers the adhesive on a d/s tape and prevents the adhesive from sticking to itself. The liner is used as a protection aid during handling/processing and storage. Most commonly used liner types are:

Paper liners (e.g. Glassine paper, PE-coated paper, Clay-coated paper)
Film liners (e.g. PP, PET, PE) Silicone is used as release system to avoid adhesion between liner material and adhesive.

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.

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

Outgassing - Amount of chemical ingredients evaporating from adhesives (e. g. monomer residues, solvents, etc.) especially under elevated temperature conditions.

Peel Adhesion - The force required to remove a pressure sensitive adhesive-coated flexible material from a surface.

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.

Primer - A coating applied to a surface (e. g. backing or a substrate) prior to the application of an adhesive, improving bond performance between backing and adhesive or between tape and substrate.

Release Force - Force needed to remove the liner from the covered adhesive layer of the d/s PSA tape, the release force can be adjusted by release agents, such as silicone.

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 PSAs 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).

Substrate - Material that the PSA tape is applied to.

Tack - Tack describes the contact behavior of the adhesive to the substrate under a minimum of time and pressure. Also referred to as "wet-grab" and "quick-stick".

Tensile Strength - Tensile strength is the force required to break the material.

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