| 摘要 |
1,162,575. Film forming copolymer dispersions. BP CHEMICALS (U.K.) Ltd. 16 April, 1968 [5 May, 1967], No. 20905/67. Heading C3P. A film-forming composition comprises an aqueous dispersion of a copolymer of (a) 5- 25% (by wt. of the total monomers) of ethylene, (b) 10-35% of vinyl chloride, and (c) 40- 85% of a vinyl ester of a saturated monocarboxylic acid, e.g. vinyl acetate or a vinyl ester of a branched chain acid. The copolymers are prepared in dispersion in the presence of a free radical initiator and a surface-active agent and/or protective colloid and the monomers are added incrementally or continuously. There may also be present a catalyst activator, e.g. ferrous sulphate, a mercaptan chain transfer agent, a difunctional monomer (up to 1% of total monomers), e.g. divinyl succinate or glycol dimethacrylate and a buffering agent to maintain a pH of 4-6. |
