Method for preparing graft copolymer and thermoplastic resin molded article
The present invention relates to a method for preparing a graft copolymer including polymerizing a conjugated diene-based monomer to prepare a small-size conjugated diene-based polymer; enlarging the small-size conjugated diene-based polymer to prepare a large-size conjugated diene-based polymer; and polymerizing the small-size conjugated diene-based polymer, the large-size conjugated diene-based polymer, an aromatic vinyl-based monomer and a vinyl cyan-based monomer to prepare a graft copolymer, wherein a weight ratio of the small-size conjugated diene-based polymer and the large-size conjugated diene-based polymer is 10:90 to 40:60 in preparing the graft copolymer.
1. A method for preparing a graft copolymer, the method comprising:
polymerizing a conjugated diene-based monomer to prepare a small-size conjugated diene-based polymer;
enlarging the small-size conjugated diene-based polymer to prepare a large-size conjugated diene-based polymer; and
polymerizing the small-size conjugated diene-based polymer, the large-size conjugated diene-based polymer, an aromatic vinyl-based monomer and a vinyl cyan-based monomer to prepare a graft copolymer with a graft ratio of 45-60%,
wherein a weight ratio of the small-size conjugated diene-based polymer and the large-size conjugated diene-based polymer is 10:90 to 40:60 in preparing the graft copolymer, and
wherein the gel content of the small-size conjugated diene-based polymer is 80 to 95%.
2. The method for preparing a graft copolymer according to claim 1 , wherein a weight ratio of the small-size conjugated diene-based polymer and the large-size conjugated diene-based polymer is 25:75 to 35:65 in preparing the graft copolymer.
3. The method for preparing a graft copolymer according to claim 1 , wherein an average particle diameter of the small-size conjugated diene-based polymer is 0.05 to 0.15 μm.
4. The method for preparing a graft copolymer according to claim 1 , wherein preparing the large-size conjugated diene-based polymer corresponds to enlargement by adding a coagulant to the small-size conjugated diene-based polymer.
5. The method for preparing a graft copolymer according to claim 4 , wherein the coagulant is one or more selected from the group consisting of phosphoric acid and acetic acid.
6. The method for preparing a graft copolymer according to claim 1 , wherein an average particle diameter of the large-size conjugated diene-based polymer is 0.3 to 0.5 μm.
7. The method for preparing a graft copolymer according to claim 1 , wherein the polymerization is performed by emulsion polymerization.
8. A thermoplastic resin molded article manufactured using a thermoplastic resin composition comprising:
the graft copolymer prepared according to claim 1 ; and
a copolymer comprising a unit derived from an aromatic vinyl-based monomer and a unit derived from a vinyl cyan-based monomer,
wherein a plating adhesion strength is 7 N/m or more.
9. The thermoplastic resin molded article according to claim 8 , wherein the thermoplastic resin molded article has an izod impact strength of 25 kg·cm/cm or more.
10. The method of claim 1 , wherein the shell of the graft copolymer has a molecular weight distribution of 1.8 to 2.7.