# US 8,784,976 B2 · Laminated polyester film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,976 B2 - Document ID: US8784976B2 - Status: Granted - Kind: B2 - Application number: 13/395,512 - Filed: 2010-09-13 - Published: 2012-07-26 - Granted: 2014-07-22 - Earliest claimed: 2009-09-23 - Assignees: Mitsubishi Plastics, Inc. - Applicants: Taishi Kawasaki; Masato Fujita - Inventors: Taishi Kawasaki; Masato Fujita - Web page: https://patentgrep.com/patent/US8784976B2 ## CPC - C08J 7/043: Improving the adhesiveness of the coatings per se, e.g. forming primers (adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50) - C08J 7/0423: {with at least one layer of inorganic material and at least one layer of a composition containing a polymer binder} - G02B 1/105 - G02B 1/14: Protective coatings, e.g. hard coatings - G02B 5/3033: {in the form of a thin sheet or foil, e.g. Polaroid} - C08J 2429/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids - Y10T 428/24942: including components having same physical characteristic in differing degree - Y10T 428/24975: No layer or component greater than 5 mils thick - Y10T 428/31797: Next to addition polymer from unsaturated monomers - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention provides a laminated polyester film which exhibits a good adhesion property to various adhesives, and can be suitably used in the applications in which a high total light transmittance is required, for example, as a member for protecting a polarizing plate of liquid crystal displays, in particularly, as a protective film disposed on a rear surface of a rear side polarizing plate. The laminated polyester film according to the present invention comprises a polyester film; a coating layer formed by applying a coating solution which comprises at least one resin selected from the group consisting of a polyester resin, an acrylic resin and a urethane resin, polyvinyl alcohol and an oxazoline compound, on one surface of the polyester film; and a coating layer formed on the other surface of the polyester film which has an absolute reflectance exhibiting one minimum value in a wavelength range of 300 to 800 nm wherein the minimum value is not more than 3.5%. ## Claims ### Claim 1 A laminated polyester film comprising a polyester film; a first coating layer formed by applying a coating solution which comprises polyvinyl alcohol, an oxazoline compound and at least one resin selected from the group consisting of a polyester resin, an acrylic resin and a urethane resin on one surface of the polyester film; and a second coating layer formed on the other surface of the polyester film which has an absolute reflectance exhibiting one minimum value in a wavelength range of 300 to 800 nm, which minimum value is not more than 3.5%; wherein the first coating layer has a thickness of 0.002 to 1.0 μm, and the second coating layer has a thickness of 0.04 to 0.15 μm. ### Claim 2 (depends on 1) A laminated polyester film according to claim 1, wherein a content of the polyester resin, acrylic resin or urethane resin in the first coating layer is 20 to 40% by weight; a content of the polyvinyl alcohol in the first coating layer is 20 to 50% by weight; and a content of the oxazoline compound in the first coating layer is 20-40% by weight. ### Claim 3 (depends on 1) A laminated polyester film according to claim 1, wherein a weight ratio of the polyester resin, acrylic resin or urethane resin:polyvinyl alcohol:oxazoline compound in the first coating layer is in the range of 1.0 to 8.0:1.0 to 8.0:1.0 to 8.0. ### Claim 4 (depends on 1) A laminated polyester film according to claim 1, wherein the urethane resin used in the first coating layer is produced by using polycarbonate polyols as a polyol. ### Claim 5 (depends on 1) A laminated polyester film according to claim 1, wherein the oxazoline compound used in the first coating layer is a polymer having an oxazoline group on a side chain thereof. ### Claim 6 (depends on 1) A laminated polyester film according to claim 1, wherein the first coating layer further comprises a melamine compound and/or an epoxy compound. ### Claim 7 (depends on 6) A laminated polyester film according to claim 6, wherein a content of the melamine compound and/or the epoxy compound in the first coating layer is 3 to 50% by weight based on a total amount of the at least one resin selected from the group consisting of the polyester resin, the acrylic resin and the urethane resin, the polyvinyl alcohol and the oxazoline compound. ### Claim 8 (depends on 6) A laminated polyester film according to claim 6, wherein the melamine compound is an alkylated melamine compound. ### Claim 9 (depends on 8) A laminated polyester film according to claim 8, wherein the alkylated melamine compound is a completely alkylated melamine compound. ### Claim 10 (depends on 9) A laminated polyester film according to claim 9, wherein the completely alkylated melamine compound is hexamethoxymethyl melamine. ### Claim 11 (depends on 6) A laminated polyester film according to claim 6, wherein the epoxy compound is a polyfunctional epoxy compound. ### Claim 12 (depends on 11) A laminated polyester film according to claim 11, wherein the polyfunctional epoxy compound is a compound having at least two glycidyl ether structures. ### Claim 13 (depends on 12) A laminated polyester film according to claim 12, wherein the compound having at least two glycidyl ether structures is a polyglycerol polyglycidyl ether. ### Claim 14 (depends on 1) A laminated polyester film according to claim 1, wherein the second coating layer comprises an acrylic resin and/or a urethane resin. ### Claim 15 (depends on 14) A laminated polyester film according to claim 14, wherein a content of the acrylic resin and/or the urethane resin in the second coating layer is not less than 40% by weight. ### Claim 16 (depends on 14) A laminated polyester film according to claim 14, wherein the urethane resin in the second coating layer is produced by using polycarbonate polyols as a polyol. ### Claim 17 (depends on 1) A laminated polyester film according to claim 1, wherein the polyester film comprises an ultraviolet absorber. ### Claim 18 A laminated polyester film comprising a polyester film; a first coating layer formed by applying a coating solution which comprises polyvinyl alcohol, an oxazoline compound and at least one resin selected from the group consisting of a polyester resin, an acrylic resin, a urethane resin and an alkylated melamine compound on one surface of the polyester film; and a second coating layer formed on the other surface of the polyester film which has an absolute reflectance exhibiting one minimum value in a wavelength range of 300 to 800 nm, which minimum value is not more than 3.5%; wherein the first coating layer has a thickness of 0.002 to 1.0 μm, and the second coating layer has a thickness of 0.04 to 0.15 μm. ### Claim 19 A laminated polyester film comprising a polyester film; a first coating layer formed by applying a coating solution which comprises polyvinyl alcohol, an oxazoline compound and at least one resin selected from the group consisting of a polyester resin, an acrylic resin, a urethane resin and a polyfunctional epoxy compound having at least two glycidyl ether structures on one surface of the polyester film; and a second coating layer formed on the other surface of the polyester film which has an absolute reflectance exhibiting one minimum value in a wavelength range of 300 to 800 nm, which minimum value is not more than 3.5%; wherein the first coating layer has a thickness of 0.002 to 1.0 μm, and the second coating layer has a thickness of 0.04 to 0.15 μm.