| 摘要 |
Graft copolymers are made by graft polymerizing monomeric material on to a latex of a rubbery copolymer of at least two monoolefines, e.g. ethylene-propylene copolymers and copolymers of ethylene, propylene and non-conjugated dienes, e.g. dicyclopentadiene, 1,4-hexadiene, and methylene norbornylene. The rubbery copolymer may be gelled either before or during the graft polymerization, by polymerizing thereon a small quantity of a polyethylenic monomer, e.g. divinyl benzene, glyceryl and tetramethylene diacrylates, ethylene dimethacrylate, tetraallyloxyethane and 1,2,4-trivinylcyclohexane. Grafting monomers specified are styrene and its derivatives, acrylic and methacrylic acids, esters and nitriles, and vinyl chloride, and mixtures of such monomers. The resulting graft copolymers may be blended with separately prepared polymers prepared from the monomers specified for grafting. The examples describe the use of: (A) ethylene-propylene bipolymers and terpolymers as starting polymers, (B) styrene, alpha-methylstyrene, acrylonitrile, methyl methacrylate and mixtures thereof as grafting monomers, (C) the abovementioned polyethylenic monomers as gelling monomers, (D) resins made from the monomers (B) for blending with the graft copolymers and (E) tert.-butyl peroxypivalate and azodiisobutyronitrile as polymerization catalysts. |
