Adhesion. IV. The meaning of tack temperature

Heretofore it has been assumed that, under the same experimental conditions of time and magnitude of applied pressure, all amorphous polymers have equal viscosities at their tack temperatures. Further evidence is obtained with a number of polymers in support of the theory. As a nonequilibrium property characterizing high polymers, tack temperature thus belongs in a category with brittle points, second‐order transition points, and softening temperatures.