| 摘要 |
A composition characterized by the transmission of at least 50% of the incident radiation of about 7000 through a layer 1/16 " thick comprises a blend of a resinous component which is polymethyl methacrylate or a copolymer of methyl methacrylate and styrene containing at least 40% by weight of the former, and a graft polymer which is the polymerization product of styrene, methyl methacrylate or a mixture thereof in a latex of polybutadiene or a rubbery copolymer of butadiene with up to 40% by weight of a mono-olefinic monomer, the ratio of the monomeric material to the butadiene polymer being at least 0,1:1 and the relative amounts of the graft polymer and the resinous component being such that the butadiene polymer comprises from 15 to 35% by weight of the mixture. Rubbery copolymers specified are those of butadiene with styrene, alpha-methyl styrene, vinyl toluene, chloro-styrenes, acrylonitrile, ethyl acrylate, methyl methacrylate and diethyl maleate and fumarate. A method is described by means of which various specified graft copolymers are prepared. Specifications 726,583, 744,455 and 749,494 are referred to. |
