Peeling test of adhesives

1. Peeling test of adhesives. The peeling test is used to determine the ability of flexible adhesives to withstand local stress concentration. Peel force is considered to act on a line, that is, line force. The softer the adherend is, the higher the modulus of the adhesive is, and the stress on the surface will tend to stress the wire, so the stress is great. Since the area of ​​the force depends on the thickness and modulus of the adherend and the adhesive, it is difficult to estimate. Therefore, it is generally considered that the acting stress and the breaking stress are the force of the thread, ie, Newton / cm ( N/cm ).

2. T- peel test ( ASTM D1876 ) is widely used for thin-film metal adherends. In this test, the load was entirely transmitted to the joint, so the measured peel strength was lower than other forms of peel test.

3. The peel strength of elastomer adhesive is related to the thickness of adhesive layer. With the increase of adhesive layer thickness, the adhesive will increase its adhesive area due to its elastic deformation. When the joint is under the same stress, the tensile stress distribution will be wide and the stress The degree of concentration is also small, so the peel strength is also relatively higher.   The T- peel test is a frequently used test method.

4. This test is mainly used to determine the resistance of two flexible adherends to peeling. The test piece is 25.4mm wide, the thickness is usually 0.5mm , the length is 304.8mm , and the length of the adhered part is only 228.6mm . The “ Bell ” peel test was performed on a 25.4mm steel roll with a fixed radius. The test piece consisted of a thin metal plate (thickness of 0.635mm ) and another metal piece that did not undergo plastic deformation during the test (thickness was 1.6 Mm ) Bonding, which is slightly different from the T- peeling angle, the measured value is slightly higher than the T- peel test and the test repeatability is better. ASTM D1781 is a metal-to-metal climbing drum peel test method, with a fixed peeling radius obtained with a rotating drum having a diameter of 100 mm .

5. The device used in the Bell test and climbing drum test is to stabilize the peeling angle, but this method of fixing the peeling radius does not guarantee that the peeling radius is constant because of the high modulus of the metal on the steel roll or the drum. The close cooperation played a resistance role.

6 , in these two methods, there is a great deal of energy consumed in metal deformation, so for a certain adhesive, they measured the peel strength is higher than the T- peel test.

7. ASTM D3167 is a test to measure the peeling strength of adhesive roller. The test piece is composed of a flexible adherend and a rigid adherend, and is suitable for measuring the peel strength of a semi-flexible adherend surfacing on a hard substrate.

8. This method is particularly useful for acceptance and process control and can be used as an alternative to ASTM D1781 (drum climbing test). Because this method has a large peeling angle, the operation is relatively strict.

9. ASTM D903 is a measure of the peeling or tearing strength of an adhesive joint. This is a standard 180 peel test. One of the adherends should have sufficient flexibility to allow it to fold.

10. When testing, peel the lower flexible foil, film or tape from a more rigid substrate (such as a relatively thick metal, plastic, glass, wood, etc.). This method is mainly used to measure the peel strength of adhesive tapes and elastic or soft materials such as rubber, fabrics, and films attached to rigid adherends.