To obtain a polymer latex capable of giving both a liquid plastisol and a foam having excellent foam quality by effecting the microsuspension polymerization of a first seed polymer (P1) containing an initiator soluble in an organic solvent, a second seed polymer (P2) having a mean particle diameter smaller than that of P1, water, an anionic emulsifier, a soluble metal salt, and a reducing agent.
The initiator used is exemplified by ammonium persulfate. The seed polymers used are exemplified by vinyl chloride homopolymers or copolymers and have two particle diameter distributions having a mean particle diameter of 0.9-1.3 μm and a mean particle diameter of 0.15-0.3 μm, respectively. The ratio of P1 to P2 is 0.7-1.8 by weight. The ratio, metal salt/organic-solvent- soluble initiator, is at most 0.09 by mole. It is advantageous that the metal of the salt is copper. The anionic emulsifier used is, for example, a fatty acid soap and is used in an amount of at most 3 wt.% based on the related monomers. The water is used in such an amount that the initial polymer concentration is 20-80 wt.%.
PERES RICHARD
ERNST BENOIT
