# US 2013/0158201 A1 · Acrylic copolymer and optical film including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0158201 A1 - Document ID: US20130158201A1 - Status: Published application - Kind: A1 - Application number: 13/805,224 - Filed: 2011-06-14 - Published: 2013-06-20 - Earliest claimed: 2010-06-21 - Assignees: LG Chem, Ltd. - Inventors: Byoung-Il Kang; Chang-Hun Han - Web page: https://patentgrep.com/patent/US20130158201A1 ## CPC - C08F 22/10: Esters - C08J 5/18: Manufacture of films or sheets - G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)} - C08F 220/1804: {C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate} - C08F 220/1806: {C6-(meth)acrylate, e.g. (cyclo)hexyl (meth)acrylate or phenyl (meth)acrylate} - C08J 2333/06: of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical - G02F 1/13363: Birefringent elements, e.g. for optical compensation - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract Provided are a heat resistant, high strength acrylic copolymer and an optical film including the same, and more particularly, an acrylic copolymer polymerized by including (1) an alkyl(meth)acrylate-based monomer excluding a tert-butyl(meth)acrylate-based monomer, (2) a (meth)acrylate-based monomer including an aliphatic ring and/or an aromatic ring, and (3) a tert-butyl(meth)acrylate-based monomer. The acrylic copolymer according to the present invention has excellent heat resistance as well as transparency being maintained. Also, the optical film including a compounding resin including the acrylic copolymer has excellent transparency, heat resistance, processability, adhesiveness, retardation properties, and durability. ## Claims ### Claim 1 An acrylic copolymer polymerized by comprising: (1) an alkyl(meth)acrylate-based monomer excluding a tert-butyl(meth)acrylate-based monomer; (2) a (meth)acrylate-based monomer including an aliphatic ring, an aromatic ring, or a combination thereof; and (3) a tert-butyl(meth)acrylate-based monomer. ### Claim 2 (depends on 1) The acrylic copolymer of claim 1, wherein an alkyl group of the alkyl(meth)acrylate-based monomer excluding a tert-butyl(meth)acrylate-based monomer has a carbon number of 1 to 10. ### Claim 3 (depends on 1) The acrylic copolymer of claim 1, wherein the alkyl(meth)acrylate-based monomer excluding a tert-butyl(meth)acrylate-based monomer is methyl (meth)acrylate. ### Claim 4 (depends on 1) The acrylic copolymer of claim 1, wherein the (meth)acrylate-based monomer including an aliphatic ring, an aromatic ring, or a combination thereof is a cycloalkyl(meth)acrylate-based monomer or an aryl(meth)acrylate-based monomer. ### Claim 5 (depends on 4) The acrylic copolymer of claim 4, wherein a cycloalkyl group of the cycloalkyl(meth)acrylate-based monomer has a carbon number of 4 to 12 and an aryl group of the aryl(meth)acrylate-based monomer has a carbon number of 6 to 12. ### Claim 6 (depends on 1) The acrylic copolymer of claim 1, wherein the (meth)acrylate-based monomer including an aliphatic ring, an aromatic ring, or a combination thereof is one or more selected from the group consisting of cyclopentyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, cyclohexyl acrylate, 2-phenoxyethyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, 3-cyclohexylpropyl methacrylate, phenyl methacrylate, 4-t-butylphenyl methacrylate, 4-methoxyphenyl methacrylate, 1-phenylethyl methacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate, 2-phenoxyethyl methacrylate, and 2-naphthyl methacrylate. ### Claim 7 (depends on 1) The acrylic copolymer of claim 1, wherein the acrylic copolymer is polymerized by comprising: 50 wt % to 98.9 wt % of the alkyl(meth)acrylate-based monomer excluding a tert-butyl(meth)acrylate-based monomer; 1 wt % to 49.9 wt % of the (meth)acrylate-based monomer including an aliphatic ring, an aromatic ring, or a combination thereof; and 0.1 wt % to 10 wt % of the tert-butyl(meth)acrylate-based monomer. ### Claim 8 (depends on 1) The acrylic copolymer of claim 1, wherein a glass transition temperature (Tg) of the acrylic copolymer is 120° C. or more. ### Claim 9 (depends on 1) The acrylic copolymer of claim 1, wherein a weight-average molecular weight of the acrylic copolymer is within a range of 50,000 to 150,000. ### Claim 10 (depends on 1) A resin composition containing the acrylic copolymer of claim 1, and a resin comprising an aromatic ring, an aliphatic ring, or a combination thereof in a main chain mixed therein. ### Claim 11 (depends on 10) The resin composition of claim 10, wherein the resin comprising an aromatic ring, an aliphatic ring, or a combination thereof in a main chain is polycarbonate. ### Claim 12 (depends on 11) The resin composition of claim 11, wherein the resin composition comprises 90 wt % to 99.9 wt % of the acrylic copolymer and 0.1 wt % to 10 wt % of the polycarbonate based on a total weight of the resin composition. ### Claim 13 (depends on 10) An optical film comprising the resin composition of claim 10. ### Claim 14 (depends on 13) The optical film of claim 13, wherein the optical film is a polarizer protective film. ### Claim 15 (depends on 14) A polarizing plate comprising a polarizer and a protective film included on at least one side of the polarizer, wherein the protective film is the optical film of claim 14. ### Claim 16 (depends on 13) The optical film of claim 13, wherein the optical film has an in-plane retardation value (Rin) expressed as the following Equation 1 in a range of 0 nm to 10 nm and a thickness retardation value (Rth) expressed as the following Equation 2 in a range of −5 nm to 5 nm: Rin=(nx−ny)×d [Equation 1] Rth=(nz−ny)×d [Equation 2] where nx is an in-plane refractive index of the film in a direction having the largest refractive index, ny is an in-plane refractive index of the film in a direction perpendicular to the nx direction, nz is a thickness refractive index, and d is a thickness of the film. ### Claim 17 (depends on 15) A liquid crystal display comprising the polarizing plate of claim 15. ### Claim 18 (depends on 17) The liquid crystal display of claim 17, wherein the liquid crystal display is a vertical alignment (VA) mode liquid crystal display.