Lg Chem, Ltd

Changhong Park

Young Hwan Jeong

Yoo Vin Kim

Jae Min Suk

Young Min Kim

Jin Hyoung Lee

Sujeong Han

Jaewon Heo

A copolymer is prepared by graft-polymerizing 20 to 40% of an aromatic vinyl compound and 1 to 20% of a vinyl cyanide compound onto 50 to 70% of conjugated diene rubber latex having a solids content of 30 to 65% by weight, coagulating the latex by adding 0.04 to 0.27 parts by weight of a first nonionic polymer coagulant, and 0.47 to 1.65 parts by weight of a second cationic polymer coagulant or 0.73 to 3.35 parts by weight of a second anionic polymer coagulant to 100 parts by weight (based on solids) of the prepared graft copolymer latex. When the second coagulant is the cationic polymer coagulant, the total weight of coagulant is 0.7 to 1.7 parts by weight, and when the second coagulant is the anionic polymer coagulant, the total weight of coagulant is 0.97 to 3.37 parts by weight.

Method of preparing vinyl cyanide compound-conjugated diene compound-aromatic vinyl compound graft copolymer, and thermoplastic resin composition including graft copolymer

A method of preparing a graft copolymer includes a step of performing coagulation by adding an acid coagulant to 100 parts by weight (based on solids) of graft copolymer latex prepared by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto conjugated diene rubber latex; and a step of performing coagulation once more by adding a salt coagulant thereto. In a resulting graft copolymer, coagulation efficiency may be improved and the gloss of the prepared graft copolymer may be increased. In addition, since a b-value measured using a Hunter lab colorimeter and a b-value measured after being left at 250&#xb0; C. for 15 minutes are low, the graft copolymer may have excellent color characteristics. In addition, since heating loss is low and scorch time is long, the graft copolymer may have excellent processing characteristics.

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Daejeon, South Korea

Changhong Park