Resin composition, optical fiber, optical fiber manufacturing method, optical fiber ribbon, and optical fiber cable

Abstract

Provided is a resin composition for the primary coating of an optical fiber, the resin composition comprising a photopolymerizable compound containing a urethane (meth) acrylate and a reactive surfactant, and a photopolymerization initiator, wherein the reactive surfactant contains at least one selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2). (In the formulae: R represents an alkylene group having 2-4 carbon atoms; R1 represents a hydrocarbon group having 1-20 carbon atoms; R2 represents a hydrogen atom or a methyl group; X represents a hydrogen atom or an -SO3NH4 group; m represents an integer of 0-100; and n represents an integer of 0-12.)

Description

Resin composition, optical fiber, optical fiber manufacturing method, optical fiber ribbon, and optical fiber cable

[0001] The present disclosure relates to a resin composition for a primary coating of an optical fiber, an optical fiber, a method for manufacturing an optical fiber, an optical fiber ribbon, and an optical fiber cable. This application claims priority to Japanese Application No. 2023-080639, filed May 16, 2023, and incorporates by reference all the contents of said Japanese application.

[0002] In recent years, there has been an increasing demand for high-density cables with increased optical fiber packing density in data center applications. Optical fibers generally have a coating resin layer to protect the glass fiber, which serves as the optical transmitter. The coating resin layer is composed of two layers: a primary resin layer in contact with the glass fiber and a secondary resin layer formed on the outer surface of the primary resin layer. As the packing density of the optical fiber increases, external forces (lateral pressure) are applied to the optical fiber, which tends to increase microbending loss. It is known that reducing the Young's modulus of the primary resin layer and increasing the Young's modulus of the secondary resin layer can improve the microbending resistance of optical fibers. For example, Patent Documents 1 to 5 describe resin compositions for primary coatings containing urethane (meth)acrylate, which is a reaction product of a polyol, a diisocyanate, and a hydroxyl group-containing (meth)acrylate.

[0003] Japanese Patent Application Laid-Open No. 2009-197163 Japanese Patent Application Laid-Open No. 2012-111674 Japanese Patent Application Laid-Open No. 2013-136783 Japanese Patent Application Laid-Open No. 2013-501125 Japanese Patent Application Laid-Open No. 2014-114208

[0004] A resin composition for a primary coating of an optical fiber according to one embodiment of the present disclosure is a resin composition containing a photopolymerizable compound including a urethane (meth)acrylate and a reactive surfactant, and a photopolymerization initiator, wherein the reactive surfactant includes at least one selected from the group consisting of a compound represented by formula (1) described below and a compound represented by formula (2) described below.

[0005] Fig. 1 is a schematic cross-sectional view showing an optical fiber according to one embodiment. Fig. 2 is a schematic cross-sectional view showing an optical fiber ribbon according to one embodiment. Fig. 3 is a schematic cross-sectional view showing an optical fiber ribbon according to one embodiment. Fig. 4 is a plan view showing the appearance of an optical fiber ribbon according to one embodiment. Fig. 5 is a schematic cross-sectional view showing an optical fiber cable according to one embodiment. Fig. 6 is a schematic cross-sectional view showing an optical fiber cable according to one embodiment.

[0006] [Problems to be Solved by the Present Disclosure] Lowering the Young's modulus of the primary resin layer may result in a lower crosslink density and poor water resistance. Specifically, when an optical fiber is immersed in water, blisters may form in the primary resin layer, which may increase transmission loss. Optical fibers are sometimes used by being housed in a cable while immersed in jelly containing oil. When an optical fiber is immersed in jelly, the primary resin layer absorbs the oil, which reduces its strength and may cause defects (voids). The generation of voids may increase transmission loss at low temperatures. Therefore, the primary resin layer is required to have excellent oil resistance.

[0007] An object of the present disclosure is to provide a resin composition that has excellent water resistance and oil resistance and can form a resin layer suitable for the primary coating of an optical fiber, and an optical fiber that has excellent water resistance and oil resistance.

[0008] [Effects of the Present Disclosure] According to the present disclosure, it is possible to provide a resin composition that has excellent water resistance and oil resistance and can form a resin layer that is suitable for the primary coating of an optical fiber, as well as an optical fiber that has excellent water resistance and oil resistance.

[0009] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0010] (1) A resin composition for a primary coating of an optical fiber according to one embodiment of the present disclosure is a resin composition containing a photopolymerizable compound including a urethane (meth)acrylate and a reactive surfactant, and a photopolymerization initiator, wherein the reactive surfactant includes at least one selected from the group consisting of a compound represented by formula (1) described below and a compound represented by formula (2) described below. Such a resin composition has excellent water resistance and oil resistance, and can form a resin layer suitable for a primary coating of an optical fiber, thereby enabling the production of an optical fiber having excellent water resistance and oil resistance.

[0011] (2) In the above (1), from the viewpoint of the water resistance, oil resistance, and low-temperature characteristics of the optical fiber, the content of the reactive surfactant may be 0.01 parts by mass or more and 5.0 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0012] (3) In the above (1), from the viewpoint of the water resistance, oil resistance, and low-temperature characteristics of the optical fiber, the content of the reactive surfactant may be 0.05 parts by mass or more and 3.5 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0013] (4) In any of the above (1) to (3), from the viewpoint of improving the curing speed of the resin composition, the photopolymerizable compound may further contain an N-vinyl compound, and the content of the N-vinyl compound may be 1 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the total amount of the resin composition.

[0014] (5) In any one of the above (1) to (4), from the viewpoint of improving the low-temperature characteristics and microbending resistance of the optical fiber, the resin composition is applied to an optical fiber having an integrated light amount of 10 mJ / cm ２ and an illumination intensity of 100 mW / cm ２ The Young's modulus of the resin film obtained by UV curing under the above conditions may be 0.10 MPa or more and 0.80 MPa or less at 23°C.

[0015] (6) In the above (5), from the viewpoint of improving the low-temperature characteristics and microbending resistance of the optical fiber, the Young's modulus of the resin film may be 0.10 MPa or more and 0.60 MPa or less at 23°C.

[0016] (7) An optical fiber according to one aspect of the present disclosure includes a glass fiber including a core and a cladding, a primary resin layer that contacts and coats the glass fiber, and a secondary resin layer that coats the primary resin layer, wherein the primary resin layer contains a cured product of the resin composition according to any one of (1) to (6). Such an optical fiber has excellent water resistance and oil resistance.

[0017] (8) A method for producing an optical fiber according to one aspect of the present disclosure includes a coating step of coating the resin composition according to any one of (1) to (6) above on the outer periphery of a glass fiber including a core and a cladding, and a curing step of curing the resin composition by irradiating it with ultraviolet light after the coating step, thereby producing an optical fiber with excellent water resistance and oil resistance.

[0018] (9) An optical fiber ribbon according to an aspect of the present disclosure includes a plurality of optical fibers as described in (7) arranged in parallel and coated with a ribbon resin. Such an optical fiber ribbon has excellent water resistance and oil resistance and can be packed densely in an optical fiber cable.

[0019] (10) An optical fiber cable according to an aspect of the present disclosure includes the optical fiber ribbon according to (9) housed within the cable. Such an optical fiber cable has excellent water resistance and oil resistance.

[0020] (11) An optical fiber cable according to an aspect of the present disclosure includes a plurality of optical fibers according to the above (7) housed within the cable. Such an optical fiber cable has excellent water resistance and oil resistance.

[0021] [Details of the Embodiments of the Present Disclosure] Specific examples of the resin composition and optical fiber according to the present embodiment will be described with reference to the drawings as necessary. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. In the following description, the same elements in the drawings will be denoted by the same reference numerals, and redundant explanations will be omitted. In this specification, "(meth)acrylate" refers to an acrylate or its corresponding methacrylate, and the same applies to other similar expressions such as (meth)acryloyl. In this specification, "ppm" refers to a mass ratio.

[0022] (Resin Composition) The resin composition according to the present embodiment is a resin composition for primary coating of an optical fiber, which contains a photopolymerizable compound including a urethane (meth)acrylate and a reactive surfactant, and a photopolymerization initiator. The resin composition according to the present embodiment is an ultraviolet-curable resin composition.

[0023] The reactive surfactant includes at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2). The reactive surfactant according to this embodiment is incorporated into crosslinks when the resin composition is cured by ultraviolet irradiation, making it possible to form a primary resin layer that is excellent in water resistance and oil resistance. Furthermore, the reactive surfactant according to this embodiment can disperse water and oil that have penetrated into the primary resin layer, thereby suppressing an increase in transmission loss of the optical fiber.

[0024]

[0025] In formula (1) and formula (2), R represents an alkylene group having 2 to 4 carbon atoms, and R １ represents a hydrocarbon group having 1 to 20 carbon atoms, and R ２ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or —SO ３ NH ４ group, m is an integer of 0 to 100, and n is an integer of 0 to 12. When m is 2 or more, the multiple Rs may be the same or different.

[0026] Examples of the alkylene group having 2 to 4 carbon atoms represented by R include an ethylene group, a propylene group, and a butylene group. From the viewpoint of achieving better water resistance and oil resistance, R may be an ethylene group. １ The number of carbon atoms in the hydrocarbon group represented by R may be 5 to 20, 8 to 18, or 10 to 15, from the viewpoint of achieving better water resistance and oil resistance. １ The hydrocarbon group represented by R may be linear, branched or cyclic. １ The hydrocarbon group represented by may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include an alkyl group having 1 to 20 carbon atoms. Examples of the aromatic hydrocarbon group include a phenyl group substituted with an alkyl group. The number of carbon atoms in the alkyl group substituted with an alkyl group may be 1 to 14 or 1 to 10. Examples of the phenyl group substituted with an alkyl group include an octylphenyl group and a nonylphenyl group. R ２ may be a hydrogen atom from the viewpoint of achieving better water resistance and oil resistance. m may be an integer of 1 to 50, 2 to 40, 3 to 30, 4 to 25, or 5 to 20. n may be an integer of 0 to 10, 0 to 8, 0 to 6, 0 to 3, or 1 to 3.

[0027] Examples of the compound represented by formula (1) include ADEKA REASOAP SR-10, SR-20, SR-1025, SR-2025, SR-3025, SE-10N, SE-1025A, ER-10, ER-20, ER-30, ER-40, NE-10, NE-20, and NE-30, all manufactured by ADEKA Corporation. Examples of the compound represented by formula (2) include Aqualon KH-05, KH-10, and KH-20, all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

[0028] The content of the reactive surfactant may be 0.01 parts by mass or more, 0.03 parts by mass or more, 0.05 parts by mass or more, 0.07 parts by mass or more, or 0.09 parts by mass or more, or may be 5.0 parts by mass or less, 4.5 parts by mass or less, 4.0 parts by mass or less, 3.5 parts by mass or less, or 3.0 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition. When the content of the reactive surfactant is 0.01 parts by mass or more, based on 100 parts by mass of the total amount of the resin composition, the water resistance and oil resistance of the optical fiber are easily improved, and when it is 5.0 parts by mass or less, the low temperature characteristics of the optical fiber are easily improved. From the viewpoint of achieving better water resistance, oil resistance, and low-temperature properties, the content of the reactive surfactant may be, based on 100 parts by mass of the total amount of the resin composition, 0.01 parts by mass or more and 5.0 parts by mass or less, 0.03 parts by mass or more and 4.5 parts by mass or less, 0.05 parts by mass or more and 4.0 parts by mass or less, 0.05 parts by mass or more and 3.5 parts by mass or less, 0.07 parts by mass or more and 3.5 parts by mass or less, or 0.09 parts by mass or more and 3.0 parts by mass or less.

[0029] Urethane (meth)acrylate is a photopolymerizable compound having a urethane bond. For example, a urethane (meth)acrylate (hereinafter, sometimes referred to as "urethane (meth)acrylate (A)") that is a reaction product of a diol, a diisocyanate, and a hydroxyl group-containing (meth)acrylate can be used as the urethane (meth)acrylate.

[0030] Examples of diols include polyether diols, polyester diols, polycaprolactone diols, polycarbonate diols, polybutadiene diols, and bisphenol A-ethylene oxide addition diols. Examples of polyether diols include polytetramethylene glycol (PTMG), polyethylene glycol (PEG), polypropylene glycol (PPG), PTMG-PPG-PTMG block copolymers, PEG-PPG-PEG block copolymers, PTMG-PEG random copolymers, and PTMG-PPG random copolymers. From the viewpoint of ease of adjusting the Young's modulus of the primary resin layer, polypropylene glycol may be used as the diol.

[0031] From the viewpoint of obtaining a Young's modulus suitable for the primary resin layer, the number average molecular weight (Mn) of the diol may be 1,800 or more and 20,000 or less, 2,000 or more and 19,000 or less, or 2,500 or more and 18,500 or less.

[0032] Examples of diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, 1,5-naphthalene diisocyanate, norbornene diisocyanate, 1,5-pentamethylene diisocyanate, tetramethylxylylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0033] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, caprolactone (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, 2-hydroxy-o-phenylphenolpropyl (meth)acrylate, 2-hydroxy-3-methacrylpropyl acrylate, trimethylolpropane di(meth)acrylate, and pentaerythritol tri(meth)acrylate. From the viewpoint of reactivity, 2-hydroxyethyl acrylate may be used as the hydroxyl group-containing (meth)acrylate.

[0034] An organotin compound may be used as a catalyst when synthesizing urethane (meth)acrylate. Examples of organotin compounds include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate, dibutyltin bis(2-ethylhexyl mercaptoacetate), dibutyltin bis(isooctyl mercaptoacetate), and dibutyltin oxide. From the viewpoint of easy availability or catalytic performance, dibutyltin dilaurate or dibutyltin diacetate may be used as the catalyst.

[0035] When synthesizing urethane (meth)acrylate, 4-methoxyphenol or 2,6-di-tert-butyl-p-cresol may be added as a polymerization inhibitor.

[0036] The method for preparing urethane (meth)acrylate (A) can be exemplified by the method of reacting diol with diisocyanate to synthesize isocyanate group (NCO)-terminated prepolymer, and then reacting hydroxyl group-containing (meth)acrylate; the method of reacting diisocyanate with hydroxyl group-containing (meth)acrylate, and then reacting diol; and the method of simultaneously reacting diol, diisocyanate and hydroxyl group-containing (meth)acrylate.When preparing urethane (meth)acrylate (A), if necessary, hydroxyl group-containing (meth)acrylate can be mixed with monohydric alcohol or active hydrogen-containing silane compound and used.

[0037] By introducing a group based on a monohydric alcohol into the urethane (meth)acrylate (A), the proportion of (meth)acryloyl groups, which are photopolymerizable groups, can be reduced, and the Young's modulus of the primary resin layer can be reduced.

[0038] Examples of monohydric alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol.

[0039] By introducing a group based on an active hydrogen-containing silane compound into the urethane (meth)acrylate (A), the proportion of (meth)acryloyl groups, which are photopolymerizable groups, can be reduced, the Young's modulus of the primary resin layer can be reduced, and the adhesion to the glass fiber can be improved.

[0040] Examples of active hydrogen-containing silane compounds include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0041] The molar ratio of NCO to OH (NCO / OH) when reacting a diol with a diisocyanate may be 1.1 or more and 4.0 or less, 1.2 or more and 3.5 or less, or 1.4 or more and 3.0 or less. The molar ratio of the hydroxyl group-containing (meth)acrylate to the NCO of the NCO-terminated prepolymer may be 1.00 or more and 1.15 or less, or 1.03 or more and 1.10 or less. When the hydroxyl group-containing (meth)acrylate is used in combination with an active hydrogen-containing silane compound or a monohydric alcohol, the molar ratio of the total of the hydroxyl group-containing (meth)acrylate, active hydrogen-containing silane compound, and monohydric alcohol to the NCO of the NCO-terminated prepolymer may be 1.00 or more and 1.15 or less, or 1.03 or more and 1.10 or less, and the molar ratio of the total of the active hydrogen-containing silane compound and monohydric alcohol to the NCO of the NCO-terminated prepolymer may be 0.01 or more and 0.5 or less.

[0042] The urethane (meth)acrylate may further contain a urethane (meth)acrylate (hereinafter, sometimes referred to as “urethane (meth)acrylate (B)”) which is a reaction product of a polyoxyalkylene monoalkyl ether, a diisocyanate, and a hydroxyl group-containing (meth)acrylate.

[0043] The polyoxyalkylene monoalkyl ether is a compound having an oxyalkylene group, an alkoxy group, and a hydroxyl group. Examples of the polyoxyalkylene monoalkyl ether include polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene alkyl (C １２ ~C １４ ) ether, polyoxyethylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene isostearyl ether, polyoxyethylene octyldodecyl ether, polyoxyethylene cholesteryl ether, polyoxypropylene butyl ether, polyoxypropylene myristyl ether, polyoxypropylene cetyl ether, polyoxypropylene stearyl ether, polyoxypropylene lanolin alcohol ether, polyoxyethylene polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene lauryl ether, polyoxyethylene polyoxypropylene cetyl ether, polyoxyethylene polyoxypropylene stearyl ether, and polyoxyethylene polyoxypropylene decyltetradecyl ether.

[0044] From the viewpoint of compatibility of the resin composition, the polyoxyalkylene monoalkyl ether may be polyoxypropylene monobutyl ether.

[0045] From the viewpoint of obtaining a Young's modulus suitable for the primary resin layer, the Mn of the polyoxyalkylene monoalkyl ether may be 2000 or more, 2100 or more, or 2200 or more, and may be 10000 or less, 8000 or less, or 7000 or less.

[0046] The Mn of the diol and polyoxyalkylene monoalkyl ether can be calculated from the hydroxyl value measured in accordance with JIS K 0070 using the following formula: The number of functional groups of the diol is 2, and the number of functional groups of the polyoxyalkylene monoalkyl ether is 1. Mn = 56.1 × number of functional groups × 1000 / hydroxyl value

[0047] From the viewpoint of obtaining a Young's modulus suitable for the primary resin layer, the Mn of the urethane (meth)acrylate (A) may be 6,000 to 50,000, 8,000 to 45,000, 9,000 to 40,000, or 10,000 to 30,000. The weight average molecular weight (Mw) of the urethane (meth)acrylate (A) may be 6,000 to 80,000, 8,000 to 70,000, 10,000 to 60,000, or 15,000 to 40,000. The Mn of the urethane (meth)acrylate (B) may be 4,000 to 20,000, 5,000 to 18,000, or 6,000 to 15,000. The Mw of the urethane (meth)acrylate (B) may be 4,000 or more and 30,000 or less, 4,500 or more and 25,000 or less, or 5,000 or more and 20,000 or less.

[0048] The Mn and Mw of the urethane (meth)acrylate (A) and the urethane (meth)acrylate (B) can be measured by gel permeation chromatography (GPC).

[0049] From the viewpoint of adjusting the Young's modulus of the primary resin layer, the content of the urethane (meth)acrylate (A) may be 15 parts by mass or more and 85 parts by mass or less, 20 parts by mass or more and 80 parts by mass or less, or 25 parts by mass or more and 75 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0050] The content of the urethane (meth)acrylate (B) may be 0 parts by mass or more and 70 parts by mass or less, 10 parts by mass or more and 65 parts by mass or less, or 20 parts by mass or more and 60 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0051] The content of the urethane (meth)acrylate may be 30 parts by mass or more and 90 parts by mass or less, 40 parts by mass or more and 80 parts by mass or less, or 45 parts by mass or more and 75 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0052] The photopolymerizable compound according to this embodiment may contain a photopolymerizable compound (hereinafter referred to as a "monomer") other than a reactive surfactant and a urethane (meth)acrylate. Examples of the monomer include a (meth)acrylic acid ester, an N-vinyl compound, and a (meth)acrylamide compound. The monomer may be a monofunctional monomer having one photopolymerizable ethylenically unsaturated group, or a polyfunctional monomer having two or more ethylenically unsaturated groups.

[0053] Examples of monofunctional (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, and isoamyl (meth)acrylate. ) acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, cyclic trimethylolpropane formal acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy ethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, nonylphenolpolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, isobornyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, and ω-carboxy-polycaprolactone (meth)acrylate.

[0054] Examples of polyfunctional (meth)acrylic acid esters include ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. , bifunctional monomers such as 1,12-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,20-eicosanediol di(meth)acrylate, isopentyldiol di(meth)acrylate, 3-ethyl-1,8-octanediol di(meth)acrylate, tricyclodecanol di(meth)acrylate, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene di(meth)acrylate, bisphenol A epoxy di(meth)acrylate, bisphenol F epoxy di(meth)acrylate, EO adduct di(meth)acrylate of bisphenol A, EO adduct di(meth)acrylate of bisphenol F, PO adduct di(meth)acrylate of bisphenol A, and PO adduct di(meth)acrylate of bisphenol F;Trimethylolpropane tri(meth)acrylate, trimethyloloctane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylate, trimethylolpropane polypropoxy tri(meth)acrylate, trimethylolpropane polyethoxypolypropoxy tri(meth)acrylate, tris[(meth)acryloyloxyethyl]isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol polyethoxytetra(meth)acrylate trifunctional or higher functional monomers such as tris[(meth)acryloyloxyethyl]isocyanurate, ...

[0055] Examples of the (meth)acrylamide compound include dimethyl(meth)acrylamide, diethyl(meth)acrylamide, (meth)acryloylmorpholine, hydroxymethyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, isopropyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, dimethylaminopropylacrylamide methyl chloride, diacetone acrylamide, (meth)acryloylpiperidine, (meth)acryloylpyrrolidine, (meth)acrylamide, N-hexyl(meth)acrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, and N-methylolpropane(meth)acrylamide.

[0056] Examples of N-vinyl compounds include N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylmethyloxazolidinone, N-vinylimidazole, and N-vinyl-N-methylacetamide.

[0057] The photopolymerizable compound may contain an N-vinyl compound, which can improve the curing rate of the resin composition. The N-vinyl compound may include at least one selected from N-vinylcaprolactam and N-vinylmethyloxazolidinone. The content of the N-vinyl compound may be 1 part by mass or more and 15 parts by mass or less, 2 parts by mass or more and 14 parts by mass or less, or 3 parts by mass or more and 13 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0058] The content of the monomer may be 5 parts by mass or more and 70 parts by mass or less, 10 parts by mass or more and 60 parts by mass or less, or 15 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0059] The photopolymerization initiator can be appropriately selected from known radical photopolymerization initiators. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone (Omnirad 184, manufactured by IGM Resins), 2,2-dimethoxy-2-phenylacetophenone (Omnirad 651, manufactured by IGM Resins), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO, manufactured by IGM Resins), ethyl (2,4,6-trimethylbenzoyl)-phenylphosphinate (Omnirad TPO-L, manufactured by IGM Resins), and 2-benzyl-2-dimethylamino-4'-morpholinobutyrophenone (Omnirad 369, manufactured by IGM Resins). Examples of suitable amines include 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (Omnirad 379, IGM Resins), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, IGM Resins), and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (Omnirad 907, IGM Resins).

[0060] The photopolymerization initiator may be used alone or in combination of two or more. From the viewpoint of excellent rapid curing properties of the resin composition, 2,4,6-trimethylbenzoyldiphenylphosphine oxide may be used as the photopolymerization initiator.

[0061] The content of the photopolymerization initiator may be 0.1 parts by mass or more and 5 parts by mass or less, 0.3 parts by mass or more and 4 parts by mass or less, or 0.4 parts by mass or more and 3 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

[0062] The resin composition according to this embodiment may further contain a sensitizer, a photoacid generator, a silane coupling agent, a leveling agent, an antifoaming agent, an antioxidant, an ultraviolet absorber, and the like.

[0063] Examples of the sensitizer include anthracene compounds such as 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-bis(2-ethylhexyloxy)anthracene; thioxanthone compounds such as 2,4-diethylthioxanthone, 2,4-diethylthioxanthen-9-one, 2-isopropylthioxanthone, and 4-isopropylthioxanthone; amine compounds such as triethanolamine, methyldiethanolamine, and triisopropanolamine; benzoin compounds, anthraquinone compounds, ketal compounds, and benzophenone compounds.

[0064] The photoacid generator includes A ＋ B － Examples of the photoacid generator include sulfonium salts such as CPI-100P, 101A, 110P, 200K, 210S, 310B, and 410S (manufactured by San-Apro Ltd.) and Omnicat 270 and 290 (manufactured by IGM Resins), and iodonium salts such as CPI-IK-1 (manufactured by San-Apro Ltd.), Omnicat 250 (manufactured by IGM Resins), and WPI-113, 116, 124, 169, and 170 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0065] Examples of silane coupling agents include tetramethyl silicate, tetraethyl silicate, mercaptopropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxy-ethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, dimethoxydimethylsilane, diethoxydimethylsilane, 3-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-(β-aminoethyl) γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, bis-[3-(triethoxysilyl)propyl]tetrasulfide, bis-[3-(triethoxysilyl)propyl]disulfide, γ-trimethoxysilylpropyldimethylthiocarbamoyltetrasulfide, and γ-trimethoxysilylpropylbenzothiazyltetrasulfide.

[0066] From the viewpoint of coatability, the viscosity of the resin composition according to this embodiment at 25°C may be 0.5 Pa·s or more and 20 Pa·s or less, 0.8 Pa·s or more and 18 Pa·s or less, or 1 Pa·s or more and 15 Pa·s or less. The viscosity of the resin composition at 25°C is measured using a rheometer ("MCR-102" manufactured by Anton Paar) with a cone plate CP25-2 and a shear rate of 10 s －１ The measurement can be performed under the following conditions.

[0067] The resin composition was exposed to an integrated light dose of 10 mJ / cm ２ and an illumination intensity of 100 mW / cm ２The Young's modulus of the resin film obtained by UV curing under the above conditions may be 0.10 MPa or more and 0.80 MPa or less at 23°C. When the Young's modulus of the resin film is 0.10 MPa or more, the low-temperature properties of the optical fiber are easily improved, and when the Young's modulus of the resin film is 0.80 MPa or less, the microbending resistance of the optical fiber is easily improved. From the viewpoint of the low-temperature properties of the optical fiber, the Young's modulus of the resin film may be 0.15 MPa or more or 0.20 MPa or more at 23°C, and from the viewpoint of the microbending resistance of the optical fiber, it may be 0.70 MPa or less, 0.60 MPa or less, or 0.50 MPa or less at 23°C. From the viewpoint of the low-temperature properties and microbending resistance of the optical fiber, the Young's modulus of the resin film may be 0.10 MPa or more and 0.60 MPa or less, 0.10 MPa or more and 0.50 MPa or less, 0.15 MPa or more and 0.50 MPa or less, or 0.20 MPa or more and 0.50 MPa or less at 23°C. The Young's modulus of the resin film can be determined by the method described in the examples.

[0068] 1 is a schematic cross-sectional view showing an optical fiber according to one embodiment. The optical fiber 10 includes a glass fiber 13 including a core 11 and a cladding 12, and a coating resin layer 16 including a primary resin layer 14 and a secondary resin layer 15 provided around the glass fiber 13.

[0069] The cladding 12 surrounds the core 11. The core 11 and the cladding 12 mainly contain glass such as silica glass, and for example, the core 11 can be made of silica glass doped with germanium or pure silica glass, and the cladding 12 can be made of pure silica glass or silica glass doped with fluorine.

[0070] 1 , for example, the outer diameter (D2) of the glass fiber 13 is approximately 100 μm to 125 μm, and the diameter (D1) of the core 11 constituting the glass fiber 13 is approximately 7 μm to 15 μm. The thickness of the coating resin layer 16 is typically approximately 22 μm to 70 μm. The thickness of each of the primary resin layer 14 and the secondary resin layer 15 may be approximately 5 μm to 50 μm.

[0071] When the outer diameter of the glass fiber 13 is about 125 μm and the thickness of the coating resin layer 16 is 60 μm or more and 70 μm or less, the thickness of each of the primary resin layer 14 and the secondary resin layer 15 may be about 10 μm to 50 μm, for example, the thickness of the primary resin layer 14 may be 35 μm and the thickness of the secondary resin layer 15 may be 25 μm. The outer diameter of the optical fiber 10 may be about 245 μm to 265 μm.

[0072] When the outer diameter of the glass fiber 13 is about 125 μm and the thickness of the coating resin layer 16 is 20 μm or more and 48 μm or less, the thickness of each of the primary resin layer 14 and the secondary resin layer 15 may be about 8 μm to 38 μm, for example, the thickness of the primary resin layer 14 may be 25 μm and the thickness of the secondary resin layer 15 may be 10 μm. The outer diameter of the optical fiber 10 may be about 165 μm to 221 μm.

[0073] When the outer diameter of the glass fiber 13 is about 100 μm and the thickness of the coating resin layer 16 is 22 μm or more and 37 μm or less, the thickness of each of the primary resin layer 14 and the secondary resin layer 15 may be about 5 μm to 32 μm, for example, the thickness of the primary resin layer 14 may be 25 μm and the thickness of the secondary resin layer 15 may be 10 μm. The outer diameter of the optical fiber 10 may be about 144 μm to 174 μm.

[0074] The method for manufacturing an optical fiber according to the present embodiment includes a coating step of coating the resin composition on the outer periphery of a glass fiber including a core and a cladding, and a curing step of curing the resin composition by irradiating it with ultraviolet light after the coating step. By applying the resin composition according to the present embodiment to the primary resin layer, an optical fiber having excellent water resistance and oil resistance can be manufactured.

[0075] From the viewpoint of improving the microbending resistance of the optical fiber, the Young's modulus of the primary resin layer may be 0.80 MPa or less, 0.70 MPa or less, 0.60 MPa or less, or 0.50 MPa or less at 23°C ± 2°C. If the Young's modulus of the primary resin layer is 0.80 MPa or less, external forces are less likely to be transmitted to the glass fiber, and an increase in transmission loss due to microbending can be suppressed. From the viewpoint of improving the low-temperature properties of the optical fiber, the Young's modulus of the primary resin layer may be 0.10 MPa or more, 0.15 MPa or more, or 0.20 MPa or more at 23°C ± 2°C.

[0076] The Young's modulus of the primary resin layer can be measured by the Pullout Modulus (POM) method at 23°C. Two locations of the optical fiber are fixed with two chuck devices, and the portion of the coating resin layer (primary resin layer and secondary resin layer) between the two chuck devices is removed. Next, one chuck device is fixed, and the other chuck device is slowly moved in the opposite direction of the fixed chuck device. When the length of the portion of the optical fiber sandwiched between the moving chuck devices is L, the amount of chuck movement is Z, the outer diameter of the primary resin layer is Dp, the outer diameter of the glass fiber is Df, the Poisson's ratio of the primary resin layer is n, and the load during movement of the chuck device is W, the Young's modulus of the primary resin layer can be calculated using the following formula: Young's modulus (MPa) = ((1 + n)W / πLZ) × ln(Dp / Df)

[0077] The secondary resin layer 15 can be formed by curing a resin composition containing, for example, a photopolymerizable compound including urethane (meth)acrylate, a photopolymerization initiator, etc. The resin composition forming the secondary resin layer has a different composition from the resin composition for the primary coating. The resin composition for the secondary coating can be prepared using a conventionally known technique.

[0078] From the viewpoint of improving the microbending resistance of the optical fiber, the Young's modulus of the secondary resin layer may be 800 MPa or more, 1000 MPa or more, or 1200 MPa or more at 23° C.±2° C. The upper limit of the Young's modulus of the secondary resin layer is not particularly limited, but from the viewpoint of imparting appropriate toughness to the secondary resin layer, it may be 3000 MPa or less, 2500 MPa or less, or 2000 MPa or less at 23° C.±2° C.

[0079] The Young's modulus of the secondary resin layer can be measured by the following method. First, the optical fiber is immersed in a mixed solvent of acetone and ethanol, and only the coating resin layer is extracted in a cylindrical shape. At this time, the primary resin layer and the secondary resin layer are integrated, but the Young's modulus of the primary resin layer is 1 / 10,000 to 1 / 1,000 of that of the secondary resin layer, so the Young's modulus of the primary resin layer can be ignored. Next, the solvent is removed from the coating resin layer by vacuum drying, and then a tensile test (tensile speed: 1 mm / min) is performed at 23°C, and the Young's modulus can be determined using the secant equation with 2.5% strain.

[0080] The method for manufacturing an optical fiber according to this embodiment uses the resin composition according to this embodiment as the resin composition for the primary coating, thereby making it possible to manufacture an optical fiber that is excellent not only in water resistance and oil resistance but also in microbending resistance and low-temperature properties.

[0081] (Optical Fiber Ribbon) The optical fibers according to this embodiment can be used to fabricate an optical fiber ribbon, which is formed by arranging a plurality of the optical fibers in parallel and coating them with a ribbon resin.

[0082] 2 is a schematic cross-sectional view showing an optical fiber ribbon according to one embodiment. The optical fiber ribbon 100 includes a plurality of optical fibers 10 and a connecting resin layer 40 in which the optical fibers 10 are (integrally) coated with a ribbon resin and connected. While FIG. 2 shows four optical fibers 10 as an example, the number is not particularly limited.

[0083] The optical fibers 10 may be integrated in a state where they are in contact with each other and arranged in parallel, or some or all of the optical fibers 10 may be integrated in a state where they are arranged in parallel with a fixed interval between them. The center-to-center distance F between adjacent optical fibers 10 may be 220 μm or more and 280 μm or less. When the center-to-center distance is 220 μm or more and 280 μm or less, the optical fibers can be easily placed in existing V-grooves, and an optical fiber ribbon with excellent bulk fusion splicing properties can be obtained. The thickness T of the optical fiber ribbon 100 may be 164 μm or more and 285 μm or less, depending on the outer diameter of the optical fibers 10.

[0084] 3 is a schematic cross-sectional view showing an example of an optical fiber ribbon in which optical fibers are integrated in a state in which they are arranged in parallel at a fixed interval. The optical fiber ribbon 100A shown in FIG. 3 is formed by connecting 12 optical fibers 10, each of which has two optical fibers 10, at a fixed interval with a ribbon resin. The ribbon resin forms a connecting resin layer 40.

[0085] The ribbon resin may be a resin material generally known as a ribbon material. From the viewpoint of preventing damage to the optical fiber 10 and facilitating its severability, the ribbon resin may contain a thermosetting resin such as a silicone resin, an epoxy resin, or a urethane resin, or an ultraviolet-curing resin such as an epoxy acrylate, a urethane acrylate, or a polyester acrylate.

[0086] When the optical fibers 10 are arranged in parallel at regular intervals, i.e., when adjacent optical fibers 10 are joined via ribbon resin without contacting each other, the thickness of the connecting portion at the center of the optical fibers 10 may be 150 μm or more and 220 μm or less. From the viewpoint of ease of deformation when the optical fiber ribbon is housed in a cable, the optical fiber ribbon may have a recess at the connecting portion of the optical fibers. The recess may be formed in a triangular shape with a narrowing angle on one side of the connecting portion.

[0087] The optical fiber ribbon according to this embodiment may have connecting portions and non-connecting portions intermittently in the longitudinal and width directions. FIG. 4 is a plan view showing the appearance of an optical fiber ribbon according to one embodiment. The optical fiber ribbon 100B has a plurality of optical fibers, a plurality of connecting portions 20, and non-connecting portions (separated portions) 21. The non-connecting portions 21 are formed intermittently in the longitudinal direction of the optical fiber ribbon. The optical fiber ribbon 100B is an intermittently connected optical fiber ribbon in which connecting portions 20 and non-connecting portions 21 are provided intermittently in the longitudinal direction for every two optical fibers 10A. A "connecting portion" refers to a portion where adjacent optical fibers are integrated via a connecting resin layer, and a "non-connecting portion" refers to a portion where adjacent optical fibers are not integrated via a connecting resin layer and there is a gap between the optical fibers.

[0088] In the optical fiber ribbon having the above configuration, the non-connecting portions 21 are intermittently provided at the connecting portions 20 provided every two fibers, making the optical fiber ribbon easily deformable. Therefore, when mounting the optical fiber ribbon in an optical fiber cable, the optical fiber ribbon can be easily rolled up and mounted, making it suitable for high-density mounting. Furthermore, the connecting portions 20 can be easily torn starting from the non-connecting portions 21, making it easy to separate the optical fibers 10 from the optical fiber ribbon into individual fibers.

[0089] The optical fiber ribbon of this embodiment uses the above optical fiber, which not only has excellent water resistance and oil resistance, but also excellent microbending resistance and low-temperature properties, and can be packed densely into an optical fiber cable.

[0090] (Optical fiber cable) In the optical fiber cable according to the present embodiment, the optical fiber ribbon is housed within the cable. Examples of the optical fiber cable include a slotted optical fiber cable having a plurality of slots (grooves). The optical fiber ribbons can be mounted within the slots so that the mounting density in each slot is approximately 25% to 65%. Mounting density refers to the ratio of the cross-sectional area of ​​the optical fiber ribbon mounted within the slot to the cross-sectional area of ​​the slot. The optical fiber cable according to the present embodiment may also be configured such that the plurality of optical fibers are housed within the cable without being coated with a ribbon resin.

[0091] An example of an optical fiber cable according to this embodiment will be described with reference to Figures 5 and 6. In Figures 5 and 6, an intermittently connected optical fiber ribbon is housed, but a bundle of optical fibers that are not coated with a ribbon resin may also be housed.

[0092] FIG. 5 is a schematic cross-sectional view of a slotless optical fiber cable 60 using the intermittently connected optical fiber ribbons 100B described above. The optical fiber cable 60 includes a cylindrical tube 61 and multiple optical fiber ribbons 100B. The multiple optical fiber ribbons 100B may be bundled together using fillers 62 such as aramid fibers. Each of the multiple optical fiber ribbons 100B may have different markings. The optical fiber cable 60 is formed by twisting multiple bundled optical fiber ribbons 100B together, extruding a resin to form a tube 61 around the bundle, and then covering the tube with a tension member 63 and an outer jacket 64. If waterproofing is required, a water-absorbing yarn may be inserted inside the tube 61. The tube 61 may be formed using a resin such as polybutylene terephthalate or high-density polyethylene. A tear cord 65 may be provided on the outside of the tube 61.

[0093] FIG. 6 is a schematic cross-sectional view of a slotted optical fiber cable 70 using the intermittently connected optical fiber ribbons 100B described above. The optical fiber cable 70 includes a slotted rod 72 having a plurality of slots 71 and a plurality of optical fiber ribbons 100B. The optical fiber cable 70 is configured such that a plurality of slots 71 are radially formed in a slotted rod 72 having a central tension member 73. The plurality of slots 71 may be twisted in a spiral or SZ shape along the longitudinal direction of the optical fiber cable 70. Each slot 71 accommodates a plurality of optical fiber ribbons 100B that have been unwound from a parallel state and placed in a dense state. Each optical fiber ribbon 100B may be bundled with an identification bundling material. A pressure winding tape 74 is wound around the slotted rod 72, and an outer jacket 75 is formed around the pressure winding tape 74.

[0094] An optical fiber cable including the optical fiber or optical fiber ribbon according to this embodiment not only has excellent water resistance and oil resistance, but also excellent microbending resistance and low-temperature properties.

[0095] The present disclosure will be described in more detail below by showing the results of evaluation tests using examples and comparative examples according to the present disclosure. Note that the present disclosure is not limited to these examples.

[0096] [Synthesis of Urethane Acrylate (A)] (A-1) Polypropylene glycol with an Mn of 3000 (manufactured by Sanyo Chemical Industries, Ltd., product name: Sannix PP-3000) and 2,4-tolylene diisocyanate (TDI) were charged into a reaction vessel so that the molar ratio of NCO to OH (NCO / OH) was 1.5. Subsequently, 200 ppm of dibutyltin dilaurate was added as a catalyst relative to the final total amount charged, and 500 ppm of 2,6-di-tert-butyl-p-cresol (BHT) was added as a polymerization inhibitor relative to the final total amount charged. Thereafter, the mixture was reacted at 60°C for 1 hour to prepare an NCO-terminated prepolymer. Next, methanol was added so that the molar ratio of OH in methanol to NCO in the NCO-terminated prepolymer (MeOH / NCO) was 0.2, and 2-hydroxyethyl acrylate (HEA) was added so that the molar ratio of OH in HEA was 0.85. The mixture was reacted at 60°C for 1 hour to obtain urethane acrylate (A-1). The urethane acrylate (A-1) had an Mn of 13,100 and an Mw of 17,700.

[0097] (A-2) Polypropylene glycol with an Mn of 4000 (manufactured by Sanyo Chemical Industries, Ltd., product name: Sannix PP-4000) and TDI were charged into a reaction vessel so that the NCO / OH ratio was 1.5. Subsequently, 200 ppm of dibutyltin dilaurate was added as a catalyst relative to the final total amount charged, and 500 ppm of BHT was added as a polymerization inhibitor relative to the final total amount charged. Thereafter, the mixture was reacted at 60°C for 1 hour to prepare an NCO-terminated prepolymer. Next, HEA was added so that the molar ratio of OH in HEA to NCO in the NCO-terminated prepolymer was 1.05, and the mixture was reacted at 60°C for 1 hour to obtain urethane acrylate (A-2). The urethane acrylate (A-2) had an Mn of 18,100 and an Mw of 23,400.

[0098] The Mn of polypropylene glycol is a value calculated from the hydroxyl value and is the value listed in the catalog of each product. The Mn and Mw of urethane acrylate were measured using a Waters ACQUITY APC RI system under the following conditions: sample concentration: 0.2 mass% THF solution, injection volume: 20 μL, sample temperature: 15 ° C, mobile phase: THF, XT column for organic solvents: particle diameter 2.5 μm, pore size 450 Å, column inner diameter 4.6 × column length 150 mm + particle diameter 2.5 μm, pore size 125 Å, column inner diameter 4.6 × column length 150 mm + particle diameter 1.7 μm, pore size 45 Å, column inner diameter 4.6 × column length 150 mm, column temperature: 40 ° C, flow rate: 0.8 mL / min.

[0099] As monomers for the resin composition for the primary coating, nonylphenol polyethylene glycol acrylate (Miramer M164, manufactured by Miwon), acryloylmorpholine (ACMO), and N-vinylcaprolactam (NVCL) were prepared. As a photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO) was prepared. As a silane coupling agent, 3-acryloxypropyltrimethoxysilane (APTMS) was prepared. As reactive surfactants, compounds represented by formula (1) and formula (2) shown in Table 1 were prepared. As other surfactants, sorbitan monooleate (Rheodol AO-10V, manufactured by Kao Corporation) and polyoxyethylene sorbitan tetraoleate (Rheodol 460V, manufactured by Kao Corporation) were prepared.

[0100]

[0101] [Resin Composition for Primary Coating] Resin compositions for primary coating of each test example were prepared by mixing the components in the amounts (parts by mass) shown in Tables 2 and 3. Test Examples 1 to 14 correspond to working examples, and Test Examples 15 to 17 correspond to comparative examples.

[0102] [Resin Film] After applying the resin composition onto a polyethylene terephthalate (PET) film using a spin coater, the resin composition was irradiated with an electrodeless UV lamp system (D bulb, manufactured by Heraeus) at an integrated light dose of 10 mJ / cm ２ and an illumination intensity of 100 mW / cm ２ The resin film was peeled off from the PET film to obtain a resin film.

[0103] (Young's Modulus) The resin film was punched into a dumbbell shape according to JIS K 7127 Type 5 and stretched using a tensile tester at 23°C, 50±10% RH, at a tension speed of 1 mm / min, with a gauge length of 25 mm, to obtain a stress-strain curve. The Young's modulus of the resin film was calculated by dividing the stress calculated using the secant equation at 2.5% strain by the cross-sectional area of ​​the resin film. The results are shown in Tables 2 and 3 below.

[0104] [Resin Composition for Secondary Coating] Polypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name: PP-600) with Mn 600 was reacted with TDI at an NCO / OH ratio of 2.0 to prepare an NCO-terminated prepolymer. Dibutyltin dilaurate was added as a catalyst in an amount of 200 ppm relative to the final total amount charged, and BHT was added as a polymerization inhibitor in an amount of 500 ppm relative to the final total amount charged. Next, HEA was added so that the molar ratio of OH in HEA to NCO in the NCO-terminated prepolymer was 1.05, and the mixture was allowed to react at 60°C for 1 hour to obtain urethane acrylate (Z-1). The urethane acrylate (Z-1) had an Mn of 2300 and an Mw of 2700.

[0105] A resin composition for secondary coating was obtained by mixing 25 parts by mass of urethane acrylate (Z-1), 36 parts by mass of tripropylene glycol diacrylate, 37 parts by mass of Viscoat #540 (manufactured by Osaka Organic Chemical Industry Ltd.), 1 part by mass of Omnirad TPO, and 1 part by mass of 1-hydroxycyclohexyl phenyl ketone (Omnirad 184).

[0106] [Optical Fiber] A resin composition for a primary coating and a resin composition for a secondary coating were each applied to the outer peripheral surface of a glass fiber 13 having a diameter of 125 μm. Next, each resin composition was cured by irradiating with ultraviolet light to form a coating resin layer 16 including a primary resin layer 14 and a secondary resin layer 15, thereby producing an optical fiber 10. The primary resin layer 14 had a thickness of 20 μm, and the secondary resin layer 15 had a thickness of 15 μm, resulting in an optical fiber having an outer diameter of 195 μm. The optical fiber was produced at a production speed of 3000 m / min.

[0107] (Water Resistance) The optical fiber 10 was immersed in water at 23°C so that the entire coating resin layer 16 was completely immersed, and the transmission loss of light with a wavelength of 1550 nm was measured using the OTDR (Optical Time Domain Reflectometer) method. After immersion for 120 days, the transmission loss of light with a wavelength of 1550 nm was measured using the OTDR method. An increase in transmission loss of less than 0.03 dB / km was rated "A," an increase in transmission loss of 0.03 dB / km or more but less than 0.05 dB / km was rated "B," and an increase in transmission loss of 0.05 dB / km or more was rated "C." The results are shown in Tables 2 and 3 below.

[0108] (Oil Resistance) The optical fiber 10 was immersed in jelly heated to 85°C for 120 days so that the entire coating resin layer 16 was completely immersed. The jelly was prepared by adding a thickener to mineral oil with an Mn of approximately 300 to 600. The transmission loss of light with a wavelength of 1550 nm was measured using the OTDR method under temperature conditions of 23°C and -40°C. A difference (transmission loss difference) between the transmission loss at -40°C and the transmission loss at 23°C of less than 0 dB / km (the transmission loss at -40°C is smaller) was evaluated as "A," a difference of 0 dB / km or more but less than 0.01 dB / km was evaluated as "B," and a difference of 0.01 dB / km or more was evaluated as "C." The results are shown in Tables 2 and 3 below.

[0109] (Low-Temperature Characteristics) An optical fiber was wound in one layer around a glass bobbin with a tension of 50 g, and the transmission characteristics of signal light with a wavelength of 1550 nm were measured by the OTDR method under the temperature conditions of 23°C and -40°C, and the transmission loss was determined. A difference in transmission loss, calculated by subtracting the transmission loss at 23°C from the transmission loss at -40°C, of ​​less than 0 dB / km was evaluated as "A," a difference of 0 dB / km or more and 0.01 dB / km or less was evaluated as "B," and a difference of more than 0.01 dB / km was evaluated as "C." The results are shown in Tables 2 and 3 below.

[0110] (Microbend Resistance Characteristics) The transmission loss of light with a wavelength of 1550 nm when the optical fiber 10 was wound in a single layer around a 280 mm diameter bobbin covered with sandpaper was measured using an OTDR (Optical Time Domain Reflectometer) method. A difference of less than 0.5 dB / km from the transmission loss of light with a wavelength of 1550 nm when the optical fiber 10 was wound in a single layer around a 280 mm diameter bobbin without sandpaper was evaluated as "A," 0.5 dB / km to 1.0 dB / km was evaluated as "B," and more than 1.0 dB / km was evaluated as "C." The results are shown in Tables 2 and 3 below.

[0111]

[0112]

[0113] DESCRIPTION OF SYMBOLS 10, 10A... Optical fiber 11... Core 12... Cladding 13... Glass fiber 14... Primary resin layer 15... Secondary resin layer 16... Coating resin layer 20... Connecting portion 21... Non-connecting portion 40... Connecting resin layer 60, 70... Optical fiber cable 61... Cylindrical tube 62... Interposer 63, 73... Tension member 64, 75... Outer jacket 65... Tear cord 71... Slot 72... Slot rod 74... Holding winding tape 100, 100A, 100B... Optical fiber ribbon

Claims

1. A glass fiber comprising a core and a cladding; a primary resin layer that contacts the glass fiber and covers the glass fiber; a secondary resin layer that covers the primary resin layer, An optical fiber, wherein the primary resin layer includes a cured product of a resin composition, the resin composition contains a photopolymerizable compound containing a urethane (meth)acrylate and a reactive surfactant, and a photopolymerization initiator; The optical fiber, wherein the reactive surfactant comprises at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2): 【Chemistry 1】 (wherein R represents an alkylene group having 2 to 4 carbon atoms, R １ represents a hydrocarbon group having 1 to 20 carbon atoms, and R ２ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or —SO ３ NH ４ group, m is an integer of 0 to 100, and n is an integer of 0 to 12.

2. 2. The optical fiber according to claim 1, wherein the content of the reactive surfactant is 0.01 parts by mass or more and 5.0 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

3. 2. The optical fiber according to claim 1, wherein the content of the reactive surfactant is 0.05 parts by mass or more and 3.5 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

4. 2. The optical fiber according to claim 1, wherein the photopolymerizable compound further comprises an N-vinyl compound, and the content of the N-vinyl compound is 1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the total amount of the resin composition.

5. 2. The optical fiber according to claim 1, wherein the primary resin layer has a Young's modulus of 0.10 MPa or more and 0.80 MPa or less at 23°C.

6. 6. The optical fiber according to claim 5, wherein the primary resin layer has a Young's modulus of 0.10 MPa or more and 0.60 MPa or less at 23°C.

7. a coating step of coating a resin composition on an outer periphery of a glass fiber including a core and a cladding; a curing step of curing the resin composition by irradiating it with ultraviolet light after the coating step; Including, the resin composition contains a photopolymerizable compound containing a urethane (meth)acrylate and a reactive surfactant, and a photopolymerization initiator; The method for producing an optical fiber, wherein the reactive surfactant comprises at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2): 【Chemistry 2】 (In the formula, R represents an alkylene group having 2 to 4 carbon atoms, R 1 represents a hydrocarbon group having 1 to 20 carbon atoms, R 2 represents a hydrogen atom or a methyl group, X represents a hydrogen atom or a —SO 3 NH 4 group, m represents an integer of 0 to 100, and n represents an integer of 0 to 12.)

8. An optical fiber ribbon, comprising a plurality of optical fibers according to any one of claims 1 to 6 arranged in parallel and coated with a ribbon resin.

9. An optical fiber cable, wherein the optical fiber ribbon according to claim 8 is housed within the cable.

10. An optical fiber cable, comprising a plurality of optical fibers according to any one of claims 1 to 6 housed within the cable.

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