| 摘要 |
Vulcanizable compositions comprise an olefin-olefin copolymer and a minor proportion of a uniformly dispersed mixture of a polymer or copolymer of a conjugated diolefin having a vinyl group in the molecule with a polymer of divinyl benzene. The said mixture may be obtained by dissolving the diolefin polymer or copolymer in monomeric divinyl benzene, with or without a hydrocarbon solvent, and polymerizing the solution obtained either thermally or by means of a free radical initiator. The diolefin polymer may have 1,2- or 3,4-enchainment obtained by polymerizing with an alkali metal catalyst; the diolefin polymer may be polybutadiene, polyisoprene or butadiene-styrene copolymer. Specified olefin-olefin copolymers are ethylene-propylene and ethylene-butene-1 copolymers. The compositions may optionally contain plasticizers, antioxidants and other additives. The compositions can be vulcanized by heating with organic peroxides, with or without sulphur. The vulcanized products have good electrical insulating properties and are suitable for forming insulation sheaths for electric cables. Specifications 856,736 and 856,737 are referred to. |
