ETHYLENE/.ALPHA.-OLEFIN/NONCONJUGATED POLYENE COPOLYMER RUBBER COMPOSITION

摘要

The ethylene/ rubber composition of the present invention comprises in specified proportions a crystalline polyolefin resin (A) and an ethylene/ rubber (B) composed of ethylene, an carbon atoms and a specific branched chain polyene compound. The molar ratio of ethylene units to units, iodine value and intrinsic viscosity ¢?! of the ethylene/ (B) are within respective specified ranges. This rubber composition is excellent in low temperature properties. Of this rubber composition, the olefinic thermoplastic elastomer composition comprising 90 to more than 40 parts by weight of component (B) per 100 parts by weight of the sum of components (A) and (B), even if being of noncrosslinked type, enables providing a molding which is excellent in tensile strength, elongation at break, rubber properties (for example, elongation set and compression set), heat resistance and low temperature properties as compared with those of the conventional noncrosslinked olefinic thermoplastic elastomers. When the above olefinic thermoplastic elastomer composition is partially or entirely crosslinked, a molding can be provided which is superior to the conventional vulcanized rubbers in low temperature properties, tensile strength, elongation at break and rubber properties. Further, the crystalline polyolefin resin composition comprising 5 to 40 parts by weight of component (B) per 100 parts by weight of the sum of components (A) and (B) enables providing a polyolefin molding which is excellent in not only rigidity and heat resistance but also impact resistance, especially, impact resistance at low temperatures.