Two step bulk polymerisation of vinyl chloride - with inclusion of pentaerythritol ester of aliphatic carboxylic acid in first step to reduce duration of temp. setting

摘要

Bulk (co)polymsn. of vinyl chloride (VC) is effected in 2 steps. The first step a VC monomer compsn. is (co)polymerised under high turbulence agitation up to a conversion of 3-15%. A complementary amt. of a VC monomer compsn. same as or different to the first one is then added and, in a second step, the (co)polymsn. is continued under slow agitation to give the final (co)polymer. The improvement is that the first step is effected in presence of an auxiliary cpd. comprising a pentaerythritol ester with a 16-20C aliphatic carboxylic acid. The process gives a (co)polymer in fine grains of dia. 30-80 microns. Duration of the first step is also reduced.