| 摘要 |
<p>A chlorinated graft polymer consists of pendant chains, predominantly of vinyl chloride, polymerized on to an elastomeric backbone of polyethylene, vinyl chloride-vinyl acetate copolymer or a chlorinated or chlorosulphonated polyolefin. The graft monomer preferably consists of at least 80% by weight of vinyl chloride and is polymerized in suspension or emulsion. The chlorination of the graft polymer may be carried out in the presence of an acyl persulphonate or ultra-violet light. The graft polymer is blended with processing aids, e.g. acrylate rubbers, styrene-acrylonitrile-butadiene or styrene-methyl styrene-butadiene terpolymers, styrene-acrylonitrile copolymers, methyl methacrylate polymers, solid aromatic residues and liquid plasticizers such as phosphate, phthalate, adipate, sebacate, azelate or mellitate esters, epoxy plasticizers and esters of citric, tartaric or ricinoleic acids or fatty acids. In Examples I, III, IV and V, chlorinated polyethylene, ethylene-vinyl acetate copolymer or polyethylene is dissolved in vinyl chloride which is then polymerized in aqueous dispersion. The resulting graft polymers are chlorinated in aqueous dispersion in the presence of (1) CCl4 and acetyl cyclohexane persulphonate or (3) HCl, CHCl3 and ultra-violet light, or (4) CCl4. In Example II, chlorinated polyethylene is suspended in an aqueous medium and grafted with vinyl chloride, the resulting graft polymer being chlorinated in dispersion in CCl4 in the presence of acetyl methyl cyclohexane persulphonate.</p> |
