Method for preparing powder including adding fluoro non-ionic surfactant after 70% polymerization is reached of vinyl chloride polymers

摘要

A method for preparing powder of a vinyl chloride polymer comprises the steps of polymerizing vinyl chloride monomer or a vinyl monomer mixture mainly comprising vinyl chloride monomer in an aqueous medium and adding, to the polymerization system, a fluorine atom-containing nonionic surfactant in an amount ranging from 0.0001 to 0.5 part by weight per 100 parts by weight of the vinyl chloride monomer or the vinyl monomer mixture mainly comprising vinyl chloride monomer after the rate of polymerization reaches at least 70% or fine powder of at least one inorganic substance having a particle size ranging from 0.001 to 50 mu m in an amount ranging from 0.001 to 1.0 part by weight per 100 parts by weight of the vinyl chloride monomer or the vinyl monomer mixture mainly comprising vinyl chloride monomer after the rate of polymerization reaches at least 70%. The method for preparing powder of a vinyl chloride polymer makes it possible to form powder of a vinyl chloride polymer which is not electrically charged during, for instance, the storage and transport thereof. The resulting polymer powder hardly causes reduction of the bulk density and flow properties.