Vinyl! chloride polymers prepn. by emulsion polymerisation - in which thermal or mechanical degradation on treatment of emulsion, is reduced

摘要

Polymers of vinyl chloride contg. is not 80% by wt. units of vinyl chloride are obtd. by emulsion polymerisation under the autogenous pressure of the monomers at -20 to -80 degrees C, (pref. 25-70 degrees C) in presence of emulsifiers and/or protective colloids, free-radical catalysts and, if necessary, regulating agents. After addn. of the monomers, polymerisation is interrupted when the reduction in pressure from the spontaneous pressure of polymerisation has reacted 1-3 bars. Much less catalyst is used than in processes where polymerisation is continued until there is a large fall in pressure on addn. of supplementary catalyst.