Abstract: A loss tangent tan ? is the ratio between a storage modulus and a loss modulus calculated from a stress when vibrations of a predetermined frequency are applied to a rubber member. When evaluating a shock resistance performance of the rubber member using an elongation at break Eb, a tensile strength at break TSb, and a loss tangent tan ? of the rubber member, a speed of an impact applied under use conditions of the rubber member is matched with a maximum speed of vibrations. As a result, the shock resistance performance can be evaluated using a value of the loss tangent tan ? corresponding to an impact actually applied to the rubber member, and it is possible to improve the accuracy of the shock resistance performance evaluation.

Abstract: This disclosure relates to a vulcanizable layered composition comprising at least two layers and at least one tie layer, wherein the first layer of the two layers comprises an fluid permeation prevention layer, the second layer of the two layers comprises at least one high diene rubber, and the tie layer comprises a mixture of: (1) about 50 to about 100 weight % of at least one halogenated isobutylene containing elastomer; (2) about 0 to about 50 weight % of at least one high diene elastomer; (3) about 20 to about 50 weight % of at least one filler; (4) about 0 to about 30 weight % of at least one processing oil; (5) about 1 to about 20 parts per hundred (phr) of at least one tackifier; and (6) at least about 0.