| 摘要 |
An improvement in the suspension polymerization of a polymerizate containing at least 80% of polyvinyl chloride with low polymer deposits by the steps of mixing (1) monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 20% by weight of olefinically mono-unsaturated compounds copolymerizable with vinyl chloride, (2) an oil-soluble free-radical forming polymerization catalyst, (3) suspension stabilizers including protective colloids, and (4) water, heating said mixture under agitation to polymerization temperatures and recovering said polymerizate, the improvement comprises using from 0.001% to 1% by weight, based on the monomers, of an unbranched dialkylperoxy dicarbonate having 16 to 18 carbon atoms in the alkyl, as the oil-soluble free-radical-forming polymerization catalyst, and adding from 0.0001% to 0.01% by weight, based on the monomers, of a water-soluble salt of nitrous acid to the polymerization charge, whereby a polymerizate is recovered with low polymer deposits. |
