PREPARATION OF FINE POWDER FROM VINYLIDENE CHLORIDE-VINYL CHLORIDE COPOLYMER

PURPOSE:To obtain easily and economically the titled fine powder, by adding a specific acrylic or methacrylic acid to vinylidene chloride and vinyl chloride monomers, suspension polymerizing the resultant mixture, and mechanically pulverizing the polymer at ordinary temperature. CONSTITUTION:(B) 1-5pts.wt., preferably 2-5pts.wt., acrylic or methacrylic ester of the formula (R is 1-12C alkyl; X is CH3 or H), e.g. methyl methacrylate, is added to (A) 100pst.wt. monomers consisting of 75-90pts.wt. vinylidene chloride and 25-10pts.wt. vinyl chloride, and the suspension polymerization of the monomers is stopped at 85wt% or less, preferably 60wt% or more, polymer yield. The resultant particles are then mechanically pulverized at ordinary temperature without cooling to 0 deg.C or below to give the aimed fine powder of the copolymer, having