Peel test

The T-peel test is used to characterise the peel behaviour of peel systems. The designation "T" refers to the presence of two peel arms, each of which is bent through 90° during the peel test, resulting in a "T-shape". The T-peel test is performed on a universal testing machine.

During the peel test, a peel load-fracture path diagram is recorded, from which the peel load F can be taken as the application-related measured variable. For the fracture-mechanical characterisation of the peel process, the energy-determined parameter adhesive energy release rate is used.

The fixed-arm peel test is used to characterise the peel behaviour of peel systems as a function of the peel angle and is carried out in accordance with the ESIS TC4 standard proposal "Peel Testing of Flexible Laminates". The designation "fixed arm" means that one of the two peel arms has an unchangeable ("fixed") peel angle of 0°, while the peel angle of the second peel arm is variably adjustable. One peel arm of the test specimen is glued to a narrow brass plate, whereby the adhesive force must be many times greater than the expected peel force. After the specimen has been prepared, the brass plate is mounted in the fixed-arm peel tester and the remaining free peel arm is clamped in the clamping device of a universal testing machine. The peel angle is generally varied between 70° and 180°, whereby a peel angle of 70° represents the lowest limit for a meaningful examination of the peel properties of peel systems as a function of the peel angle, since for peel angles < 70° shear within the sealed seam is to be expected as the cause of failure. To realise a constant peel angle during the entire peel process, the fixed-arm peel tester can be moved sideways.