Budnick Converting ^®

Understanding Testing Methods

PEEL ADHESION

The PSTC defines peel adhesion as 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. It measures the bond breaking, not the bond formation, and wetting and viscoelastic behavior mitigate the factors. This number is often represented in oz/in.

TACK

Tack is 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 adhesives to wet the surface it contacts quickly. When measuring tack, the bond formation is recorded after less than one second at low pressure and debonded in less than 0.01 seconds.

Tack adhesion tests are measured in one of two ways: Rolling ball tack where a stainless steel ball is released onto a strip of tape at a 30° angle. The distance the ball travels is measured, generally in inches or centimeters. Loop tack is where a piece of tape is looped, adhesive side out, and quickly dipped onto a substrate and removed. This is measured in oz/in.

SHEAR

Shear refers to the slow movement of the adhesive or backing under stress - it is sometimes referred to as the holding power of the tape. It is measured in two ways, static or dynamic. Static shear is measured with a static load applied to the adhesive pulling it vertically downward from the substrate. Dynamic shear is measured by a horizontal stress on the bond leading to either cohesive or adhesive failure.

TENSILE STRENGTH and ELONGATION

Tensile strength is the measure of the tape’s strength relative to its construction and can be considered the breaking point of the measurement of elongation, which is the increase or decrease in a dimension of the tape expressed as a % change.

CARRIERS AND BACKINGS

Carriers are an essential component of adhesive tapes and can influence adhesive properties and performance. The characteristics of carriers/backings can impact the selection of the proper tape for the application.

MAJOR FACTORS OF CARRIERS/BACKINGS

LAMINATE BACKINGS

Laminate backings can be created by combining various elements such as polyolefin films, aluminum foil, paper, skrims, and/or cloth.