Patent ID: 6245848
Filing Date: 2001-06-12
Classification: C08F,C08L

Abstract:
A process for producing a latex containing two populations of particles of homo- or copolymer of vinyl chloride, respectively exhibiting mean diameters of between 0.9 and 1.3 .mu.m and between 0.15 and 0.3 .mu.m. in proportions such that the ratio by weight of the population with the lesser mean diameter to that with the greater mean diameter is between 0.4 and 0.7, which comprises polymerizing, under microsuspension conditions, the corresponding monomer or monomers in the presence of a first seeding polymer (P1), the particles of which contain at least one organosoluble initiator, of a second seeding polymer (P2), the particles of which have a mean diameter less than that of the particles of the first seeding polymer (P1), of water, of an anionic emulsifier, of a soluble metal salt, in an amount such that the metal salt/organosoluble initiator molar ratio is less than 0.09, and of a reducing agent, wherein the reducing agent is the metabisulphite of an alkali metal.