# US 12,111,494 B2 · Optical fiber and method for manufacturing optical fiber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,494 B2 - Document ID: US12111494B2 - Status: Granted - Kind: B2 - Application number: 17/789,287 - Filed: 2021-08-31 - Published: 2023-02-09 - Granted: 2024-10-08 - Earliest claimed: 2020-09-04 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Sumitomo Electric Industries, Ltd. - Inventors: Takahiro Nomura; Kazuyuki Sohma - Web page: https://patentgrep.com/patent/US12111494B2 ## CPC - G02B 6/02395: {Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104)} - G02B 6/1221: {made from organic materials} - C08F 2/50: with sensitising agents - C08F 20/30: containing aromatic rings in the alcohol moiety - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract An optical fiber includes a glass fiber including: a core and a cladding; and a coating resin layer coating the glass fiber in contact with the glass fiber; wherein the coating resin layer has a primary resin layer coating the glass fiber in contact with the glass fiber and a secondary resin layer coating the primary resin layer, the primary resin layer contains a cured product of a first resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, the secondary resin layer contains a cured product of a second resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, and an amount of the phosphine oxide-based photopolymerization initiator remaining unreacted in the coating resin layer is 0.5 mass % or less. ## Claims ### Claim 1 An optical fiber comprising: a glass fiber including a core and a cladding; and a coating resin layer coating the glass fiber in contact with the glass fiber, wherein the coating resin layer has a primary resin layer coating the glass fiber in contact with the glass fiber and a secondary resin layer coating the primary resin layer, the primary resin layer comprises a cured product of a first resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, the secondary resin layer comprises a cured product of a second resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, an amount of the phosphine oxide-based photopolymerization initiator remaining unreacted in the coating resin layer is 0.5 mass % or less, and the first resin composition and the second resin composition do not contain any photopolymerization initiators other than the phosphine oxide-based photopolymerization initiator. ### Claim 2 (depends on 1) A method for manufacturing the optical fiber according to claim 1, the method comprising: an application step of applying the first resin composition and the second resin composition to a glass fiber having a temperature of 80° C. or lower such that the first resin composition and the second resin composition are distant from the glass fiber in this order; and a curing step of curing the resin compositions by radiating ultraviolet rays after the application step. ### Claim 3 (depends on 2) The method for manufacturing the optical fiber according to claim 2, wherein ultraviolet rays emitted by an ultraviolet light emitting diode are radiated in the curing step. ### Claim 4 (depends on 3) The method for manufacturing the optical fiber according to claim 3, wherein wavelengths of the ultraviolet rays are within a region of 350 nm to 405 nm. ### Claim 5 An optical fiber comprising: a glass fiber including a core and a cladding; and a coating resin layer coating the glass fiber in contact with the glass fiber, wherein the coating resin layer has a primary resin layer coating the glass fiber in contact with the glass fiber and a secondary resin layer coating the primary resin layer, the primary resin layer comprises a cured product of a first resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, the secondary resin layer comprises a cured product of a second resin composition containing a photopolymerizable compound and a phosphine oxide-based photopolymerization initiator, and an amount of the phosphine oxide-based photopolymerization initiator remaining unreacted in the coating resin layer is 0.5 mass % or less, and wherein at least one of the first resin composition or the second resin composition contains nonylphenol polyethylene glycol acrylate as the photopolymerizable compound, and an amount of the nonylphenol polyethylene glycol acrylate remaining unreacted in the coating resin layer is less than 1.0 mass %. ### Claim 6 (depends on 5) The optical fiber according to claim 5, wherein the second resin composition further contains an acetophenone-based photopolymerization initiator. ### Claim 7 (depends on 5) A method for manufacturing the optical fiber according to claim 5, the method comprising: an application step of applying the first resin composition and the second resin composition to a glass fiber having a temperature of 80° C. or lower such that the first resin composition and the second resin composition are distant from the glass fiber in this order; and a curing step of curing the resin compositions by radiating ultraviolet rays after the application step. ### Claim 8 (depends on 7) The method for manufacturing the optical fiber according to claim 7, wherein ultraviolet rays emitted by an ultraviolet light emitting diode are radiated in the curing step. ### Claim 9 (depends on 7) The method for manufacturing the optical fiber according to claim 7, wherein wavelengths of the ultraviolet rays are within a region of 350 nm to 405 nm.