| 摘要 |
1282683 Graft polymers AMERICAN CYANAMID CO 18 March 1970 [17 April 1969] 13093/70 Heading C3G A rubbery polymer based on a monomer contennt of (1) 50 to 99À5% by weight of ethylene, (2) 0À5 to 50% of vinyl acetate, a C 1 to C 18 -alkyl acrylate or methacrylate, acrylic acid or methacrylic acid and (3) up to 20% of another comonomer and containing sites reactive with a polyalkyl ether of a polymethylolmelamine is crosslinked with the said polyalkyl ether prior to, during or subsequent to grafting with a monomer comprising (a) at least 50% by weight of methyl methacrylate, (b) up to 50% of vinyl acetate or a C 1 to C 18 -alkyl acrylate and (c) up to 20% of another comonomer. A polymer of the graft monomer(s) may be blended with the graft polymer before or after it has been crosslinked. The graft polymer may be prepared by a two-stage process in which additional monomer and, optionally, additional free radical catalyst and a chain transfer agent are added in the second stage. In examples, monomer (2) is selected from acrylic acid, vinyl acetate, lauryl methacrylate, stearyl acrylate, ethyl acrylate, methacrylic acid, stearyl or methyl methacrylate, monomer (3) is beta-hydroxyethyl methacrylate, methacrylamide, alphahydroxypropyl methacrylate, methyl crotonate, acrylamide, maleic anhydride, acrylonitrile, vinyl chloride or vinylidene chloride, or a partially hydrolysed ethylene-vinyl acetate copolymer is used; graft monomer (b) is selected from vinyl acetate, ethyl acrylate, methyl acrylate, t-butyl acrylate and graft monomer (c) from methyl methacrylate, stearyl methacrylate, acrylonitrile, and styrene. The graft polymers produced are cross-linked with hexakismethoxymethyl melamine, a mixed methylated - methylolated melamine, tetramethyl ether of hexamethylol melamine, dibutyl ether of trimethylol melamine, pentaethyl ether of hexamethylol melamine, butylated hexamethylol melamine, mixed methyl and ethyl ether of hexamethylol melamine, or triethyl ether of pentamethylol melamine, in the presenc of p-toluene sulphonic acid. In Example 15, a copolymer of methyl methacrylate and ethyl acrylate is blended with a graft polymer of said methacrylate and acrylate on an ethylene/vinyl acetate/acrylic acid terpolymer before crosslinking with hexakismethoxymethyl melamine and said acid. Reference has been directed by the Comptroller to Specification 1,208,345. |
