METHOD FOR PREPARING GRAFT COPOLYMER, GRAFT COPOLYMER, AND RESIN COMPOSITION COMPRISING THE SAME

The present invention relates to a method for preparing a graft copolymer, a graft copolymer prepared therefrom, and a resin composition including the same, wherein the method includesintroducing a polymer coagulant latex including a polymer coagulant to a rubbery polymer latex including a rubbery polymer and coagulating the polymer coagulant latex to prepare an enlarged rubbery polymer latex containing an enlarged rubbery polymer (S10), and introducing an aromatic vinyl-based monomer and a vinyl cyan-based monomerto the enlarged rubbery polymer latex prepared in Step (S10) above and performing graft polymerization to prepare a graft copolymer latex including a graft copolymer (S20), wherein the polymer coagulant includes an acid group-containing copolymer having a weight average molecular weight of 550,000 g/mol to 750,000 g/mol, and the content of the vinyl cyan-based monomer introduced in Step (S20) above is 15 wt% to 24 wt% based on the total content of the aromatic vinyl-based monomer and the vinyl cyan-based monomer.