What is Peel Adhesion?
A pressure-sensitive adhesive (PSA) tape is used in various fields because it can be applied instantaneously with rather weak pressure and is easy to remove. Specifically, across multiple forefront industries, such as the fabrication of liquid crystal panels, semiconductors, optical instruments, and solar batteries, as well as medical treatment, the automobile industry, architecture, and IT, the unique capability of PSA is applied to production processes and device components.
PSA tape is valued based on three basic elements: the so-called tack test, adhesion, and shear-holding power. In general, the peel test quantitatively measures adhesion forces at 90º and 180º angles, as specified in JIS Z0237:2009.
At 180º, the peel test result is influenced by the thickness and degree of elasticity of the PSA tape. At a 90º angle, the result is less influenced by these tape characteristics and is more reliable and consistent for evaluating adhesion and cohesion. However, the test result is unsatisfactory at present due to the deviation from a 90º angle arising from the sagging and elongation of the tape.
Conventional Multi-angle Peel Test Method
Peel testers for multi-angle measurements are already available. To maintain a constant peel angle, linear movement of the substrate and a tilted detector element are used, satisfying the geometrical condition shown in Fig. 1.
The following formula shows the peel angle:
The peel distance 
equals the tensile distance 
, but the sample stage travels horizontally from A to A’ indicated as 
.
The relational calculus is expressed as the following formula,
where Lp is the velocity of the stage movement.
Fig.1: Principle of the conventional multi-angle peel test method
Flat Plate Cross Stage Peel Test Method
Kyowa Interface Science Co., Ltd. invented the Flat Plate Cross Stage Method. The synchronized actuator mechanism is designed to evaluate flat plate sliding at specified crossed angles relative to the pulling direction on a high-accuracy stage.
Refer to Fig.2, a flat cross stage shifts in the direction of A while a stage moves toward the direction of B at the same distance and speed.
Fig.2: Principle of the Kyowa's Flat Plate Cross Stage peel test method
Related Products
VPA series
- Peel Tester