| 摘要 |
New copolymers have vinyl chloride as the major component and, as a minor component (e.g. 0.1-5%), an organo-tin compound having a vinyl group attached directly to the tin atom. Another organo-vinyl component, e.g. vinyl acetate, may be present in a smaller proportion than the vinyl chloride. The organo-tin compound may contain besides the vinyl group hydrocarbon radicals other than vinyl, e.g. ethyl or butyl, and/or acyloxy radicals directly attached to the tin atom. The products are stable to light and heat, even with a low proportion of the tin compound. Copolymerization is preferably effected in emulsion in water containing a suitable dispersing agent, e.g. partly saponified polyvinyl acetate, and a catalyst, e.g. lauryl peroxide. Plasticization of a copolymer of monovinyl diethyl tin laurate with vinyl chloride, followed by hot calendering, gives substantially colourless sheets. Fractional precipitation of the copolymer followed by an estimation of the tin content of the various fractions shows uniform copolymerization. |
