摘要：

1410187 Flameproof polymer compositions, their production and expendable compositions BAYER AG 20 Oct 1972 [20 Oct 1971] 48399/72 Headings C3P and C3C A flame-proofed polymer is produced by a process in which 1-40 wt. per cent (based on the total mixture) of a copolymer of vinyl chloride and ethylene containing 5-20 wt. per cent of ethylene units and having an intrinsic viscosity in cyclohexane at 25 C. of from 0.2 to 1.5 dl./g., up to 50 wt. per cent of the vinyl chloride being optionally replaced by a copolymerizable monomer, is dissolved or swelled in 60-99 wt. per cent (based on the total mixture) of styrene or a mixture of styrene and up to 50 wt. per cent (based on the styrene) of a copolymerizable monomer, and the styrene or styrene/copolymerizable monomer mixture is polymerized. The invention also comprises a novel flameproofed polymer which comprises a copolymer of styrene with up to 50 wt. per cent (based on the styrene) of a copolymerizable monomer, and from 1-40 wt. per cent based on the polymer mixture, of a copolymer of vinyl chloride and ethylene having an ethylene content and viscosity as defined above, and wherein up to 50 wt. per cent of the vinyl chloride has been replaced by a copolymerizable monomer. In the example, styrene alone, and copoly- (ethylene/vinyl chloride) are used, the polymerization being in aqueous suspension. Suitable comonomers to replace up to 50 wt. per cent of the vinyl chloride are, vinyl acetate, allyl acetate, propylene, vinyl laurate or vinyl stearate. Suitable comonomers for the styrene are alpha-methyl styrene, a nuclear halogenated styrene, p-t-butyl styrene, acrylonitrile, methacrylonitrile or a C 1-8 ester of acrylic or methacrylic acid. None of these are exemplified. An expanding agent in an amount of 3-15 wt. per cent (based on the polymer/monomer starting mixture or the total polymer after polymerization), such as methane, ethane, ethylene, propane, butane, pentane, neopentane, hexane, methylene chloride, cyclohexane, dichlorodifluoromethane or trifluorotrichloroethane, a sulphohydrazide or an azodinitrile; and pore regulators such as sodium bicarbonate, pyrogenic silica or boric acid, may also be present. Those in italic were used in the example.

展开