PROCESS OF PREPARATION OF FINE PARTICLES OF POLYMERS IN POWDER FORM

摘要

Process for the preparation of finely divided polymer powders by polymerisation of water-soluble monomers in the aqueous phase of a water-in-oil emulsion in the presence of water-in-oil emulsifiers and polymerisation initiators, removal of water from the resulting water-in-oil polymer suspension by an azeotropic method and isolation of the suspended finely divided polymer powder, wherein either the polymerisation of the water-soluble monomers is carried out in the presence of 0.1 to 10% by weight, based on the monomers used in the polymerisation, of protective colloids or the protective colloids are added to the water-in-oil polymer suspension after the end of the polymerisation. The polymerisation is preferably carried out in the presence of a wetting agent. The finely divided pulverulent polymers are used as flocculants or thickeners for aqueous systems.