Suspension polymerisation of vinyl! chloride - with catalyst addn. between initiation and polymerisation temps., to reduce crust formation

摘要

PVC, vinyl chloride copolymers or graft polymers are prepd. by suspension polymerisation. The polymerisation catalyst is added at a temp. between start of initiation and polymerisation temp. Polymers obtd. have a porous core, resulting in higher plasticiser absorption. Encrustation of reactor walls, crust and lump formation in polymer are reduced, e.g. from 55 g. to 0.5 g. K-value is unchanged.