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 it is easy to remove. Specifically, in various forefront industries, such as in the fabrication of liquid crystal panels, semiconductors, optical instruments, solar batteries, and in medical treatment, the automobile industry, architecture, and IT, the unique capability of PSA is applied to the production process as well as constitutive parts in devices.
PSA tape is valued at the three basic elements, the so-called tack test, its adhesion, and its shear holding power. In general, the purpose of the peel test is to measure adhesion forces quantitatively at 90º and 180º angles in response to JIS Z0237:2009.
At a 180º angle, the result of the peel test is influenced by the thickness and degree of elasticity degree of the PSA tape. At a 90º angle, the result of the peel test is less influenced by these characteristics of the tape and is more reliable and consistent for the evaluation of adhesion and cohesion. However, the test result is unsatisfactory at the present due to the deviation from a 90º angle arising from the sagging and elongation of the tape.
A peel analyzer of any angle is already available on the market. To maintain the peel angle constant, linear movement of a substrate and a tilted detector element is utilized by simply satisfying the geometrical condition as shown in Fig. 1. The peel angle is shown by the following formula;
The peel distance 
is equal to the distance of 
but the stage of substrate moves horizontally from A to A’ indicated as
in Fig. 1.
The relational calculus is expressed as the following formula,
where Lp is the velocity of the stage movement.
Fig.1 The principle of the conventional peel-off method
The Flat Plate Cross Stage Method was invented by Kyowa Interface Science Co., Ltd.
The synchronized actuator mechanism is designed to realize high accuracy evaluation of flat plate sliding at specified crossed angles with the pulling direction on a 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 The principle of the Flat Cross Stage method