Reducing monomer content of vinyl chloride polymers - by heating powder after or during contact with aliphatic monohydric alcohol

摘要

Residual vinyl chloride monomer content of homo-, co- or graft polymers, contg. >=50 wt.% polymerised vinyl chloride units, is reduced by heating the powdered polymer after removing most of unreacted monomer. Heat-treatment takes 10-360 mins. at 75-120 degrees C. Polymer is contacted, before and/or during heat-treatment, for >=15 mins., with 0.01-15 (0.2-5) esp. 0.5-3 wt.% (w.r.t. polymer) of >=1 1-24(8-18) esp. 10-14C aliphatic, satd. or unsatd. opt. branched cpd. contg. 1 free OH gp. Process is partic. suitable for bulk-polymerised polymers contg. >=80 wt.% polymerised vinyl chloride units. Vinyl chloride monomer content is reduced without discolouration of the polymer. Polymer properties are not impaired. Process can take place continuously, e.g. in polymerisation vessel.