| 摘要 |
Graft copolymers are made by subjecting to free radical polymerization (A) a preformed copolymer of ethylene and a vinyl ester of a C1-C8 monocarboxylic acid, the copolymer containing 20 to 80% by weight of the ester, and (B) a mixture of 60 to 95% by weight of vinyl chloride and 5 to 40% by weight of one or more other copolymerizable monomers, the preformed copolymer and monomer mixture being used in amounts such that the resulting graft copolymer contains 25 to 67% by weight of the former. Specified monomers for use with vinyl chloride are acrylic and methacrylic acids and the esters and amides thereof, maleic anhydride, mono- and di-esters of maleic and fumaric acids, and esters of vinyl alcohol. The graft polymerization may be carried out in organic solvents, aqueous emulsion or, preferably, aqueous suspension. The examples describe grafting on to ethylene-vinyl acetate copolymers in aqueous media mixtures of vinyl chloride and: (1 and 3) hydroxypropyl methacrylate and monododecyl maleate, the resulting copolymers being cross-linkable by the hexamethyl ether of hexamethylol melamine or hexamethylene diisocyanate, (2 and 10) monopropyl maleate, (4) vinyl acetate, (5) ethyl acrylate and monopropyl maleate, (6 and 9) hydroxypropyl methacrylate, (7) ethyl acrylate, (8) n-butyl acrylate, vinyl acetate and hydroxypropyl methacrylate, (11) n-butyl acrylate, (12) n-butyl acrylate and the butyl ether of N-methylol acrylamide, and (13) ethyl acrylate and vinyl chloroacetate. Polymerization in the above processes is catalysed by lauroyl peroxide and azodiisobutyronitrile. The graft copolymers are used to make films, impregnations and coatings. |
