MOISTURE CROSS-LINKING OF VINYL CHLORIDE HOMOPOLYMERS AND COPOLYMERS

摘要

A vinyl chloride homopolymer or copolymer composition contains a silane, a compound capable of generating free radicals and a stabilizer comprising a lead compound or an organotin compound which is effective to prevent discoloration and degradation of the homopolymer or copolymer and does not inhibit the grafting of the vinyl silane on the homopolymer or copolymer. The graft homopolymer or copolymer is exposed to moisture to cross-link it, suitably after molding or otherwise fabricating the graft polymer to form an article. There is also provided a method of moisture cross-linking poly(vinyl chloride) and vinyl chloride copolymers. This process comprises the grafting of the PVC resin with vinyltrialkoxysilane in the presence of initiator, preferably a peroxide, followed by the hydrolysis of the alkoxy group of the silane to yield a cross-linked structure through the formation of Si-O-Si bonds. The present invention describes the moisture cross-linking of a thermoplastic PVC compound using vinyltrialkoxysilane and suitable stabilizers to keep degradation to a minimum thereby making an end product and the process commercially viable.