PURPOSE: To reduce scale deposition markedly and to obtain a (co)polymer in high yields, by (co)polymerizing vinyl chloride at a specified temperature in the presence of a specified polymerization initiator.
CONSTITUTION: In polymerizing a vinyl chloride monomer or copolymerizing vinyl chloride with another vinyl monomer at 55W70°C, use is made of, as a polymerization initiator, a peroxide mixture of a compound of formula I (wherein R1 and R2 are each a 2W4C alkyl or alkylene), a compound of formula II and/ or a compound of formula III (wherein R1 and R2 are as defined above). Scale deposition is markedly small and, in addition, retardation of polymerization scarcely occur and the polymer can be produced in high yields because the polymerization initiator has excellent sustained effect. Further, temperature control during the reaction is easy because the polymerization curve is linear, and so the polymerization proceeds at a constant rate. The produced polymer is excellent in heat stability, especially initial coloration as compared with polymers of conventional processes.
HAGII HIDEHIKO
KATOU MITSUKUNI
