Application Studies / Revisiting Dynamic Lap Shear Method for Evaluating Tapes

Revisiting Dynamic Lap Shear Method for Evaluating Tapes

Industry:

Adhesives

Attributes measured:

shear strength

intercept time

force at intercept

distance at intercept

peak force

distance at peak force

distance to initiate shear

complete area of work

Background

For many decades the Static Holding Power test has been the accepted method of evaluating the shear resistance of a pressure sensitive adhesive. This classic method tends not only to give variable results, but they are then reported in mixed units, either as time to fall, or the amount of movement in a given time, making comparisons difficult. What is proposed in the conversion of this test to a dynamic one, by determining the force required to disentangle the molecular structure at a very slow rate. The proposed method is fully explained and examples given. The lap shear test is performed on the TA.XTPlus with constant data collection to generate many more attributes than available with the traditional method. Characteristics of individual adhesives were easily differentiated.