s (e.g. ethylene-propylene copolymer, propylene-butene-1 copolymer and ethylene-butene-1 copolymer); copolymers of olefins and dienes (e.g. terpolymers of ethylene, propylene and dienes, such as butadiene, hexadiene, dicyclopentadiene and ethylidene norbornene); and natural rubbers;