MODIFICATION OF THERMOPLASTIC VULCANIZABLE RUBBER USING RANDOM PROPYLENE COPOLYMER

摘要

PROBLEM TO BE SOLVED: To obtain the subject thermoplastic vulcanizable rubber that can provide articles manifesting excellent properties in the elongation at breakage, toughness or the like and having large elongation by modifying a thermoplastic vulcanizable rubber with a random propylene copolymer. SOLUTION: The rubber composition comprises about 20-85 pts.wt. of (A) rubber and about 15 - about 80 pts.wt. of (B) a semi-crystalline polypropylene and (C) random propylene copolymer in total where the weight ratio of the component B to the component C is about 100/2-100/400 and further the component C contains about 80 - about 95 wt.% of the repeating units originating from propylene and about 5 - about 20 wt.% of the repeating units originating from ethylene or other 4-12C unsaturated olefin monomer. The component A includes natural rubber, a halogenated copolymers of butyl rubber or the like with a 4-7C iso-monoolefin, and a butyl rubber containing the repeating units originating from divinylbenzene.