Patent ID: 6906134

Claim:
A process for preparing an ABS graft copolymer comprising the steps of introducing to a) 40 to 80 weight parts of rubber latex comprising i) 10 to 50 weight parts of large diameter polybutadiene rubber latex having a particle diameter of 2500 to 3500 Å, gel contents of 60 to 80%, and a swelling index to 12 to 30; and ii) 50 to 90 weight parts of large diameter polybutadiene rubber latex having a particle diameter of 2500 to 3500 Å, gel contents of 81 to 97%, and a swelling index of 18 to 40, b) 20 to 60 weight parts of a monomer mixture of two or more kinds selected from a group consisting of aromatic vinyl compounds and vinyl cyanide compounds to prepare a graft copolymer, wherein 5 to 30 wt % of the monomer mixture is introduced in a batch, and simultaneously 70 to 95 wt % of the monomer mixture is started to be continuously introduced in an emulsified state, and introducing a water-soluble polymerization initiator in the batch-introduction of the monomer mixture; and introducing a liposoluble polymerization initiator in the continuous introduction of the monomer mixture in the emulsified state.