PRODUCTION OF RUBBER-MODIFIED STYRENIC RESIN.

摘要

This invention relates to a method of producing a rubber-modified styrenic resin having an excellent impact resistance and containing rubber particles of a weight-mean particle diameter of 1.5 to 4 mu m, which comprises: supplying continuously to a first reactor of complete mixing type a starting material comprising 100 parts by weight of a polymerization feed consisting of 98 to 88 % by weight of a styrenic monomer or a mixture thereof with a copolymerizable comonomer and 2 to 12 % by weight of a highly viscous rubbery polymer having a viscosity of 400 to 2,000 cP in a 5 wt.% solution thereof in styrene at 25 DEG C, 0.01 to 0.2 parts by weight of an organic peroxide, and 0 to 30 parts by weight of an inert organic solvent; conducting prepolymerization in this reactor under a condition wherein rubber phase inversion does not occur as yet; supplying a continuously withdrawn prepolymerizate to a second reactor of complete mixing type; granulating the rubbery polymer in this reactor while keeping the conversion of the monomer(s) in the feed below 40 % by weight; and enhancing the conversion in the subsequent reactor(s).