still for framstellning of for hardbearbetning lempade emulgatorhaltiga vinyl chloride polymers

摘要

An improved process for the production of emulsifier-containing vinyl chloride polymers suitable for hard processing, the particle diameter of 90% of which is more than 63 mu , by polymerization of vinyl chloride and optionally monomers copolymerizable therewith in an aqueous emulsion in the presence of water-soluble catalysts and alkali salts of carboxylic acids as emulsifiers at pH 9.5-11.5 and spray-drying the thus-obtained latex, is characterized by conducting the polymerization in a dispersion containing at least 45% by weight of monomers with sodium or potassium salts of fatty acids of 8-18 carbon atoms as emulsifiers to a conversion of at least 80%, and, during the spray-drying step, reducing the pH to 6.0-8.0.