# US 11,993,737 B2 · Surface protection film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,737 B2 - Document ID: US11993737B2 - Status: Granted - Kind: B2 - Application number: 16/618,162 - Filed: 2018-05-29 - Published: 2020-10-29 - Granted: 2024-05-28 - Earliest claimed: 2017-05-31 - Assignees: Bando Chemical Industries, Ltd. - Applicants: Bando Chemical Industries, Ltd. - Inventors: Yutaka Kamada; Arata Tani; Toshihiko Horie; Soh Kato - Web page: https://patentgrep.com/patent/US11993737B2 ## CPC - C09J 7/29: Laminated material (metallised plastics C09J7/22) - B32B 7/027: Thermal properties - B32B 7/06: permitting easy separation - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 27/08: of synthetic resin - B32B 27/18: characterised by the use of special additives - B32B 27/281: {comprising polyimides} - B32B 27/325: {comprising polycycloolefins} - B32B 27/36: comprising polyesters - B32B 27/365: {comprising polycarbonates} - B32B 27/40: comprising polyurethanes - C09J 7/201: {characterised by the release coating composition on the carrier layer} - C09J 7/25: based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds - C09J 7/405: {characterised by the substrate of the release liner} - C09J 201/00: Adhesives based on unspecified macromolecular compounds - G02B 1/14: Protective coatings, e.g. hard coatings - G06F 3/041: Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means - B32B 2250/02: 2 layers - B32B 2250/04: 4 layers - B32B 2307/30: having particular thermal properties - B32B 2307/412: Transparent - B32B 2307/536: Hardness - B32B 2307/538: Roughness - B32B 2307/546: Flexural strength; Flexion stiffness - B32B 2307/584: Scratch resistance - B32B 2307/712: Weather resistant - B32B 2307/7265: Non-permeable - B32B 2307/732: Dimensional properties - B32B 2307/748: Releasability - B32B 2571/00: Protective equipment - C09J 2203/326: for bonding electronic components such as wafers, chips or semiconductors - C09J 2301/122: the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape - C09J 2301/312: parameters being the characterizing feature - C09J 2400/226: in the substrate - C09J 2475/006: in the substrate - 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) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The present invention addresses the problem of providing a surface protection film which provides an excellent writing sensation when a touch pen is used thereon and excellent scratch resistance against a touch pen. As a solution, provided is a surface protection film which has on the outermost surface thereof a protection layer formed of a polyurethane, wherein the polyurethane has an international rubber hardness degree (IRHD) of 87.0-98.0 and a tan δ peak value of 0.6 or more. ## Claims ### Claim 1 A surface protection film, comprising: a protective layer made of a polyurethane on an outermost surface thereof, wherein the polyurethane has an international rubber hardness degree (IRHD) of 87.0 or more and 98.0 or less, a tan δ peak value of 0.6 or more and 1.39 or less, and a tan δ peak temperature of −20° C. or more and 36.2° C. or less, the protective layer has a thickness of 150 μm or more and 300 μm or less, and the polyurethane is a thermally cured product of a material composition comprising at least a polyol, an isocyanate, and an alcohol curing agent, the alcohol curing agent comprises 60 to 80 parts by weight of dihydric alcohol and 40 to 20 parts by weight of trihydric alcohol, and a ratio (—OH/—NCO) between a number of moles of hydroxyl groups (—OH) contained in the alcohol curing agent and a number of moles of isocyanate groups (—NCO) of the isocyanate in which the polyurethane is not thermally cured is 1.05 or more and 1.3 or less. ### Claim 2 (depends on 1) The surface protection film of a display according to claim 1, wherein the polyurethane is a polycarbonate-based polyurethane or a polyester-based polyurethane. ### Claim 3 (depends on 1) The surface protection film of a display according to claim 1, wherein at least three layers of the protective layer made of a polyurethane, a transparent base film, and an adhesive layer are laminated in this order. ### Claim 4 (depends on 3) The surface protection film of a display according to claim 3, wherein the polyurethane is a polycarbonate-based polyurethane or a polyester-based polyurethane. ### Claim 5 (depends on 1) A surface protection film laminate, comprising: a mold release film laminated on a surface of the surface protection film of a display according to claim 1 on the protective layer side; and a release film laminated on the other surface thereof. ### Claim 6 A method for producing a surface protection film of a display having a protective layer made of a polyurethane on an outermost surface thereof and the polyurethane having an international rubber hardness degree (IRHD) of 87.0 or more and 98.0 or less, and a tan δ peak value of 0.6 or more and 1.39 or less, comprising: pouring a material composition into a gap between first and second gap holding members sent out using a pair of rolls spaced apart from each other; and thermally curing the material composition while the material composition is held between the first and second gap holding members to form the protective layer, wherein the polyurethane has a tan δ peak temperature of −20° C. or more and 36.2° C. or less, the protective layer has a thickness of 150 μm or more and 300 μm or less, and the polyurethane is a thermally cured product of a material composition comprising at least a polyol, an isocyanate, and an alcohol curing agent, the alcohol curing agent comprises 60 to 80 parts by weight of dihydric alcohol and 40 to 20 parts by weight of trihydric alcohol, and a ratio (—OH/—NCO) between a number of moles of hydroxyl groups (—OH) contained in the alcohol curing agent and a number of moles of isocyanate groups (—NCO) of the isocyanate in which the polyurethane is not thermally cured is 1.05 or more and 1.3 or less. ### Claim 7 (depends on 6) The method for producing a surface protection film of a display according to claim 6, wherein the polyurethane is a polycarbonate-based polyurethane or a polyester-based polyurethane. ### Claim 8 (depends on 6) The method for producing a surface protection film of a display according to claim 6, wherein one of the first and second gap holding members is set as a transparent base film of the surface protection film. ### Claim 9 (depends on 8) The method for producing a surface protection film of a display according to claim 8, wherein the other of the first and second gap holding members is a film having unevenness and the material composition is held on a side of the film having unevenness. ### Claim 10 (depends on 6) The method for producing a surface protection film of a display according to claim 6, wherein one of the first and second gap holding members is a film which is not subjected to a release treatment and the other thereof is a film which is subjected to a release treatment. ### Claim 11 (depends on 10) The method for producing a surface protection film of a display according to claim 10, wherein the other of the first and second gap holding members is a film having unevenness and the material composition is held on a side of the film having unevenness.