Shear Resistance

The shear strength of a pressure sensitive label or tape can be used as a guide to the resistance to adhesive bleed. Adhesive bleed is the "oozing" of adhesive beyond the perimeter of the face material. Adhesive bleed usually associated with heavy coat weight adhesives or adhesives with low temperature flow.

Test pieces are applied to the specified area of a "standard" substrate test plate such as float glass, stainless steel or other surface of interest using a rubber covered roller. The test plate is clamped in a jig at a 2° angle and a weight attached to the free end of the test piece. The time taken for the test strip to adhesively shear from the test plate is recorded.

Smithers Pira testing is based on FINAT test method 8.