Flame-retardant molding compositions comprising a copolymer of a vinylaromatic monomer and an unsaturated dicarboxylic acid anhydride, polyvinyl chloride and a graft polymer.

摘要

Styrene/maleic anhydride polymers can be made more resistant to combustion by incorporation therein of minor amounts of polyvinyl chloride. The compositions comprise:
<UnorderedLists id="ula01" listStyle="none"><ListItem>A. from 20 to 85 % by weight of a uniform polymer comprising 50 to 85 % by weight of a vinylaromatic monomer, from 15 to 30 % by weight of an unsaturated dicarboxylic acid anhydride and from 0 to 20 % of a copolymerizable monomer.</ListItem><ListItem>B. from 15 to 40% by weight of polyvinyl chloride; and</ListItem><ListItem>C. from 0 to 40 % by weight of a composition comprising a graft copolymer of from 20 to 40 % by weight of a monomer selected from the group consisting of methyl methacrylate and acrylonitrile and 80 to 60% by weight of a vinyl aromatic monomer, said copolymer being grafted on to from 10 to 60 % of the weight of the composition of a substrate rubber having a glass transition temperature below 0° C.</ListItem></UnorderedLists>