Emulsion polymerisation of vinyl chloride in two stages - first under strong stirring and then slower stirring

摘要

In polymerising vinyl chloride in emulsion in presence of 0.005-0.5 wt. % initiators, by homogenising the emulsion to obtain a monomer particle size of 0.1-3 mu and then polymerising with heating and stirring, the improvement consists of polymerising to a conversion of 30-80% with rapid stirring and then continuing polymerising with gentle stirring. The first stage stirring is pref. 3-20 times stronger than the second stage stirring. Improved heat dissipation is achieved without significant coagulation of the polymer formed. The polymer is partic. suitable for plastisols.