# US 2023/0057580 A1 · Styrene copolymer, thermoplastic resin composition, and method of preparing styrene copolymer and thermoplastic resin composition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0057580 A1 - Document ID: US20230057580A1 - Status: Published application - Kind: A1 - Application number: 17/788,891 - Filed: 2021-07-09 - Published: 2023-02-23 - Earliest claimed: 2020-11-10 - Assignees: LG Chem, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Mincheol JU; Hyung Sub LEE; Dae Woo LEE; Jae Bum SEO; Minseung SHIN; Sungwon HONG; Insoo KIM - Web page: https://patentgrep.com/patent/US20230057580A1 ## CPC - C08F 212/08: Styrene - C08F 2/20: with the aid of macromolecular dispersing agents - C08F 212/12: Monomers containing a branched unsaturated aliphatic radical or a ring substituted by an alkyl radical - C08F 220/14: Methyl esters {, e.g. methyl (meth)acrylate} - C08F 220/44: Acrylonitrile - C08F 265/04: on to polymers of esters - C08L 25/16: Homopolymers or copolymers of alkyl-substituted styrenes - C08L 33/12: Homopolymers or copolymers of methyl methacrylate - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract The present disclosure relates to a styrene copolymer, a thermoplastic resin composition, and methods of preparing the styrene copolymer and the thermoplastic resin composition. More particularly, the present disclosure relates to a styrene copolymer having a low residual oligomer content and excellent transparency due to uniform polymerization of components to be added; and a thermoplastic resin composition including the styrene copolymer and an acrylic rubber graft copolymer and being suitable for a molded article having excellent heat resistance, scratch resistance, and surface appearance. ## Claims ### Claim 1 A method of preparing a styrene copolymer, comprising: adding a reaction solution comprising 100 parts by weight of a monomer mixture comprising 35 to 65% by weight of a (meth)acrylate-based monomer, 10 to 30% by weight of a vinyl cyanide-based monomer, and 20 to 40% by weight of an aromatic vinyl-based monomer including an alkyl-substituted styrene; 100 to 200 parts by weight of a water-based solvent; and 0.1 to 10 parts by weight of a dispersant to a reactor to perform polymerization, wherein some of the aromatic vinyl-based monomer is fed into the reactor batchwise before start of the polymerization, and a remainder of the aromatic vinyl-based monomer is continuously fed into the reactor from a time point when a temperature of the reactor reaches 90 to 110° C. to perform the polymerization. ### Claim 2 (depends on 1) The method according to claim 1, wherein a weight ratio of the batchwise fed aromatic vinyl-based monomer to the continuously fed aromatic vinyl-based monomer is 1:0.4 to 1:2. ### Claim 3 (depends on 1) The method according to claim 1, wherein a weight ratio of the aromatic vinyl-based monomer to the (meth)acrylate-based monomer is 1:1 to 1:8. ### Claim 4 (depends on 1) The method according to claim 1, wherein the alkyl-substituted styrene includes styrene in which one or more hydrogens are substituted with an alkyl group having 1 to 3 carbon atoms. ### Claim 5 (depends on 1) The method according to claim 1, wherein, in the reactor, the polymerization is performed at 80 to 130° C. and 400 to 600 rpm for 8 to 10 hours. ### Claim 6 (depends on 1) The method according to claim 1, further comprising adjusting a pH of polymerization slurry generated in the reactor to 1 to 4. ### Claim 7 (depends on 1) The method according to claim 1, wherein the dispersant is a phosphate metal salt. ### Claim 8 (depends on 1) A styrene copolymer prepared by the method according to claim 1 and having a glass transition temperature (Tg) of 115° C. or higher, an oligomer content of 0.51% by weight or less, and a refractive index of 1.55 or less. ### Claim 9 (depends on 8) The styrene copolymer according to claim 8, wherein, based on 100% by weight in total of the styrene copolymer, the styrene copolymer comprises 39 to 47% by weight of the (meth)acrylate-based monomer, 18 to 21% by weight of the vinyl cyanide-based monomer, and 35 to 43% by weight of the alkyl-substituted styrene. ### Claim 10 (depends on 8) The styrene copolymer according to claim 8, wherein the styrene copolymer has a haze of 0.3% or less and a color b value of 6.0 to 7.0. ### Claim 11 A thermoplastic resin composition, comprising: a styrene copolymer comprising a (meth)acrylate-based monomer, a first vinyl cyanide-based monomer, and a first aromatic vinyl-based monomer; and a graft copolymer comprising an acrylic-based rubber polymer, a second aromatic vinyl-based monomer, and a second vinyl cyanide-based monomer, wherein, based on 100% by weight in total of the styrene copolymer, the styrene copolymer comprises 39 to 47% by weight of the (meth)acrylate-based monomer, 18 to 21% by weight of the first vinyl cyanide-based monomer, and 35 to 43% by weight of an alkyl-substituted styrene. ### Claim 12 (depends on 11) The thermoplastic resin composition according to claim 11, wherein the first aromatic vinyl-based monomer includes the alkyl-substituted styrene, and the second aromatic vinyl-based monomer includes styrene. ### Claim 13 (depends on 1, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45) A method of preparing a thermoplastic resin composition, comprising: mixing 55 to 75% by weight of the styrene copolymer prepared by the method according to claim 1 and 25 to 45% by weight of a graft copolymer comprising an acrylic-based rubber polymer, a second aromatic vinyl-based monomer, and a second vinyl cyanide-based monomer and performing melt-kneading and extrusion. ### Claim 14 (depends on 11) A molded article including the thermoplastic resin composition according to claim 11.