Suspension polymerisation esp. of vinyl chloride - using vinyl alcohol-vinyl ester-vinyl ether copolymer as protective colloid

摘要

Suspension (co)polymerisation ofethylenically unsatd. cpds. esp. vinly chloride takes place in the presence of a water-soluble protective colloid (I) (I) is a vinyl alcohol-vinyl ester-vinyl ether copolymer having formula (where x is 60-99 (80-95) mol% and y is 0.5-30 (8-2) mol % R1 is =5C alkyl orcycloalkyl, pref. propyl or butyl R2 is =12C alkyl, cycloalkyl or alkylaryl, Residual ester gp. content is pref. 15-1 mol. %). In suspension polymerisation of vinyl chloride, used of (I), leads to grain having higher porosity, increased plasticiser absorption and absorption rate and narrow grain-size distribution. Bulk wt. is reduced. Deposition of agglomerates or films on autoclave walls is prevented. In an example, protective colloid used in vinyl chloride polymerisation was 0.05 wt. % polyvinyl alcohol-vinyl isobutyl ether-vinyl acetate contg. 15.7 mol% residual acetyl.