# US 2018/0024283 A1 · Polarizing film, pressure-sensitive-adhesive-layer-attached polarizing film, and image display device and method for continuously producing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0024283 A1 - Document ID: US20180024283A1 - Status: Published application - Kind: A1 - Application number: 15/549,788 - Filed: 2016-02-09 - Published: 2018-01-25 - Earliest claimed: 2015-02-13 - Assignees: Nitto Denko Corporation - Applicants: Nitto Denko Corporation - Inventors: Yusuke Motegi; Satoshi Mita; Tomonori Ueno; Atsushi Kishi; Jingfan Xu - Web page: https://patentgrep.com/patent/US20180024283A1 ## CPC - G02B 5/305: {including organic materials, e.g. polymeric layers} - B32B 27/30: comprising vinyl {(co)polymers; comprising acrylic (co)polymers} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM ## Abstract The present invention pertains to a polarizing film having a transparent resin layer on at least one side of a polarizer containing a polyvinyl alcohol-based resin, wherein the transparent resin layer has a thickness of 0.2 μm or more and is formed from a layer-forming material containing a polyvinyl alcohol-based resin having a saponification degree of 96 mol % or more, and wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is less than 1 wt %. This polarizing film has crack-resistant properties, and can minimize degradation of the optical characteristics in a heating and humidifying test. ## Claims ### Claim 1 A polarizing film having a transparent resin layer on at least one side of a polarizer containing a polyvinyl alcohol-based resin, wherein the transparent resin layer has a thickness of 0.2 μm or more and is formed from a layer-forming material containing a polyvinyl alcohol-based resin having a saponification degree of 96 mol % or more, and wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is less than 1 wt %. ### Claim 2 (depends on 1) The polarizing film according to claim 1, wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is 0.5 wt % or less. ### Claim 3 (depends on 1) The polarizing film according to claim 1, wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is 0.3 wt % or less. ### Claim 4 (depends on 1) The polarizing film according to claim 1, wherein the polyvinyl alcohol-based resin in the transparent resin layer has a saponification degree of 99 mol % or more. ### Claim 5 (depends on 1) The polarizing film according to claim 1, wherein the polyvinyl alcohol-based resin in the transparent resin layer has a saponification degree of 99.5 mol % or more. ### Claim 6 (depends on 1) The polarizing film according to claim 1, wherein the polyvinyl alcohol-based resin in the transparent resin layer has an average polymerization degree of 2000 or more. ### Claim 7 (depends on 1) The polarizing film according to claim 1, wherein the transparent resin layer has a thickness of 0.4 μm or more. ### Claim 8 (depends on 1) The polarizing film according to claim 1 wherein the transparent resin layer has a thickness of 6 μm or less. ### Claim 9 (depends on 1) The polarizing film according to claim 1, wherein the polarizer has a thickness of 15 μm or less. ### Claim 10 (depends on 1) The polarizing film according to claim 1, wherein the polarizer contains boric acid in an amount of 20 wt % or less based on the total amount of the polarizer. ### Claim 11 (depends on 1) The polarizing film according to claim 1, wherein the polarizer is designed to have a single-body transmittance T and a polarization degree P representing optical properties satisfying the condition of the following formula: P>-(100.929T−42.4−1)×100 (provided that T<42.3) or P≧99.9 (provided that T≧42.3). ### Claim 12 (depends on 1) The polarizing film according to claim 1, which has a protective film. ### Claim 13 (depends on 1) A pressure-sensitive-adhesive-layer-attached polarizing film having the polarizing film according to claim 1 and a pressure-sensitive adhesive layer. ### Claim 14 (depends on 13) The pressure-sensitive-adhesive-layer-attached polarizing film according to claim 13, wherein a separator is laminated on the pressure-sensitive adhesive layer. ### Claim 15 (depends on 14) The pressure-sensitive-adhesive-layer-attached polarizing film according to claim 14, which is in the form of a roll. ### Claim 16 (depends on 1) An image display device having the polarizing film according to claim 1. ### Claim 17 (depends on 15) A method for continuously producing an image display device, the method comprising the steps of: unwinding the pressure-sensitive-adhesive-layer-attached polarizing film from the roll of the pressure-sensitive-adhesive-layer-attached polarizing film according to claim 15; feeding the pressure-sensitive-adhesive-layer-attached polarizing film with the separator; and continuously bonding the pressure-sensitive-adhesive-layer-attached polarizing film to a surface of an image display panel with the pressure-sensitive adhesive layer interposed therebetween. ### Claim 18 (depends on 13) An image display device having the pressure-sensitive-adhesive-layer-attached polarizing film according to claim 13.