Dispersing stabilizer for suspension polymerization of vinyl chloride

摘要

A dispersing stabilizer suitable for suspension polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride which can be used in a hot water charging polymerization process without any problems, and which can produce vinyl chloride homopolymer or copolymers having a good porosity, a large bulk density, a very low content of coarse particles and good physical properties, the dispersing stabilizer comprising a polyvinyl alcohol having a degree of hydrolysis of 75 to 85% by mole, an absorbance of not less than 0.1 measured at a wavelength of 280 m mu with respect to the 0.1% by weight aqueous solution, a content of carboxyl group of 0.01 to 0.15% by mole and a cloud point of not less than 50 DEG C. measured with respect to the 0.1% by weight aqueous solution.