| 摘要 |
1,185,775. Suspension polymerization. FUJI SHASHIN FILM K.K. 9 Feb., 1968 [9 Feb., 1967], No. 6542/68. Heading C3P. The aqueous suspension polymerization of an ethylenically unsaturated compound is carried out in the presence of a dispersing agent and a compound of formula wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom or a methyl group. The polymerizable compound maybe styrene, a (meth)acrylic ester, butadiene, isoprene, acrylonitrile or vinyl acetate. The dispersing agent may be a weakly water soluble salt or a water soluble high molecular weight compound, examples of the former being calcium or magnesium carbonate, zinc oxide, cadmium sulphide or calcium orthophosphate, and examples of the latter are lime treated gelatine, starch, dextrins, saponified polyvinyl acetate, sodium polyacrylate or sulphonated polystyrene. The compound of the above general formula is preferably present in an amount from 0À01 to 10 parts by weight to 100 parts of monomer. In the examples, a styrenemethyl methacrylate copolymer, a methyl methacrylate homopolymer or a styrene homopolymer, are prepared in the presence of benzoyl peroxide as catalyst, and sulphonated polystyrene, lime-treated gelatine or basic magnesium carbonate as dispersing agent, and in the presence of a compound of the above general formula wherein R 1 and R 2 are methyl groups. A fine, transparent grained polymer is obtained.
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