# US 8,784,987 B2 · Pressure-sensitive adhesive composition for optical films, pressure-sensitive adhesive optical film and image display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,987 B2 - Document ID: US8784987B2 - Status: Granted - Kind: B2 - Application number: 12/954,102 - Filed: 2010-11-24 - Published: 2011-03-24 - Granted: 2014-07-22 - Earliest claimed: 2008-03-14 - Assignees: Nitto Denko Corporation - Applicants: Yuusuke Toyama; Shinichi Inoue; Mizue Nagata; Toshitsugu Hosokawa - Inventors: Yuusuke Toyama; Shinichi Inoue; Mizue Nagata; Toshitsugu Hosokawa - Web page: https://patentgrep.com/patent/US8784987B2 ## CPC - C09J 133/14: of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen - C09J 7/385: {Acrylic polymers} - C08L 2312/08: by silane - G02F 2202/28: Adhesive materials or arrangements - Y10T 428/2848: Three or more layers - Y10T 428/2891: including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A pressure-sensitive adhesive layer for optical films. The pressure-sensitive adhesive layer can prevent light leakage caused by stress associated with dimensional change of a component such as an optical film, that has reworkability, and that has satisfactory processability. A pressure-sensitive adhesive optical film produced using the layer is also provided. The pressure-sensitive adhesive layer is prepared with the use of a composition which includes a (meth)acrylic polymer including (a) 34 to 94% by weight of an alkyl (meth)acrylate monomer unit, (b) 5 to 50% by weight of an aromatic ring-containing (meth)acrylate monomer unit, and (c) 0.01 to 0.5% by weight of an amino group-containing (meth)acrylate monomer unit; 0.01 to 2 parts by weight of a peroxide as a crosslinking agent; and 0.01 to 2 parts by weight of a silane coupling agent based on 100 parts by weight of the (meth)acrylic polymer. ## Claims ### Claim 1 A pressure-sensitive adhesive layer for an optical film obtained by forming a coating of the pressure-sensitive adhesive composition comprising: a (meth)acrylic polymer comprising (a) 34 to 94% by weight of an alkyl (meth)acrylate monomer unit, (b) 5 to 50% by weight of an aromatic ring-containing (meth)acrylate monomer unit, and (c) 0.01 to 0.5% by weight of an amino group-containing (meth)acrylate monomer unit; 0.01 to 2 parts by weight of a peroxide based on 100 parts by weight of a (meth)acrylic polymer; and 0.01 to 2 parts by weight of a silane coupling agent based on 100 parts by weight of a (meth)acrylic polymer; and subjecting the coating to a crosslinking reaction, wherein the coating has a gel fraction of 55 to 95% by weight and a refractive index of less than 1.50 one hour after the formation of the coating, wherein the (meth)acrylic polymer has a weight average molecular weight of 1,800,000 to 2,800,000 as determined by gel permeation chromatography. ### Claim 2 (depends on 1) The pressure-sensitive adhesive layer according to claim 1, wherein the coating has a gel fraction of 60 to 95% by weight one week after the formation of the coating. ### Claim 3 (depends on 1) The pressure-sensitive adhesive layer according to claim 1, wherein the coating has a gel fraction of 40 to 95% by weight after standing at 23° C. and 65% RH for one week and then drying at 90° C. for 120 hours, which differs by 20% by weight or less from the gel fraction of the coating after standing at 23° C. and 65% RH for one week. ### Claim 4 (depends on 1) A pressure-sensitive adhesive optical film, comprising: an optical film; and the pressure-sensitive adhesive layer according to claim 1 formed on at least one side of the optical film. ### Claim 5 (depends on 4) The pressure-sensitive adhesive optical film according to claim 4, wherein it has a holding power (H) of 20 to 350 μm one week after the formation of the pressure-sensitive adhesive layer. ### Claim 6 (depends on 5) The pressure-sensitive adhesive optical film according to claim 5, wherein it shows an adhesive force (F1) of 1 N/25 mm to 10 N/25 mm, when it is peeled at a peel angle of 90° and a peel rate of 300 mm/minute after the steps of making it 25 mm wide, bonding it to an alkali-free glass plate through the pressure-sensitive adhesive layer by one reciprocation of a 2 kg roller, and allowing it to stand at 23° C. for one hour. ### Claim 7 (depends on 5) The pressure-sensitive adhesive optical film according to claim 5, wherein it shows an adhesive force (F2) of 2 N/25 mm to 15 N/25 mm, when it is peeled at a peel angle of 90° and a peel rate of 300 mm/minute after the steps of making it 25 mm wide, bonding it to an alkali-free glass plate through the pressure-sensitive adhesive layer by one reciprocation of a 2 kg roller, and allowing it to stand at 23° C. for one hour and then dried at 60° C. for 48 hours. ### Claim 8 (depends on 4) An image display, comprising at least one piece of the pressure-sensitive adhesive optical film according to claim 4.