Resin composition for colored coating on optical fiber, optical fiber, and optical fiber ribbon

Abstract

This resin composition for colored coating on an optical fiber contains a photopolymerizable compound, a polydimethylsiloxane compound, a photopolymerization initiator, and titanium oxide, wherein the photopolymerizable compound includes an epoxy di(meth)acrylate, the content of the epoxy di(meth)acrylate is 30-75 parts by mass with respect to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, the polydimethylsiloxane compound has a dimethylsiloxane unit and an alkylene oxide unit, and the mole percent of the dimethylsiloxane unit is 12-80 mol% on the basis of the total amount of the dimethylsiloxane unit and the alkylene oxide unit.

Description

Resin composition for colored coating of optical fiber, optical fiber, and optical fiber ribbon

[0001] This disclosure relates to a resin composition for use in coloring and coating optical fibers, an optical fiber, and an optical fiber ribbon. This application claims priority to Japanese Patent Application No. 2022-134777, filed on August 26, 2022, and incorporates the entire contents of said Japanese application by reference.

[0002] Generally, optical fibers have a coating resin layer for protecting the glass fiber that serves as the optical transmission medium. The coating resin layer includes, for example, a primary resin layer and a secondary resin layer. The outermost layer of the coating resin layer is a colored resin layer for identifying the optical fiber (see, for example, Patent Documents 1 to 3).

[0003] Japanese Patent Application Laid-Open No. 6-242355 Japanese Patent Application Laid-Open No. 2003-279811 International Publication No. 2016 / 047002

[0004] A resin composition for optical fiber coloring and coating according to one embodiment of the present disclosure contains a photopolymerizable compound, a polydimethylsiloxane compound, a photopolymerization initiator, and titanium oxide, wherein the photopolymerizable compound contains an epoxy di(meth)acrylate, and the content of the epoxy di(meth)acrylate is 30 parts by mass or more and 75 parts by mass or less, relative to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound; the polydimethylsiloxane compound has dimethylsiloxane units and alkylene oxide units, and the molar ratio of the dimethylsiloxane units based on the total amount of the dimethylsiloxane units and the alkylene oxide units is 12 mol % or more and 80 mol % or less.

[0005] Fig. 1 is a schematic cross-sectional view showing an example of an optical fiber according to the present embodiment. Fig. 2 is a schematic cross-sectional view showing an example of an optical fiber according to the present embodiment. Fig. 3 is a schematic cross-sectional view showing an example of an optical fiber ribbon according to the present embodiment.

[0006] [Problem to be Solved by the Present Disclosure] The resin composition for forming the colored resin layer contains an inorganic pigment such as titanium oxide. Since the inorganic pigment has a larger specific gravity than the resin component, settling of the inorganic pigment may occur during storage of the prepared resin composition. Furthermore, if the resin composition is not applied uniformly when forming the colored resin layer, variations in the coating diameter may occur, which may result in breakage of the optical fiber. Therefore, resin compositions for colored coatings of optical fibers are required to have not only excellent storage stability but also excellent coatability.

[0007] An object of the present disclosure is to provide a resin composition for coloring coatings of optical fibers, which has excellent storage stability and coatability, an optical fiber, and an optical fiber ribbon.

[0008] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a resin composition for coloring coating of optical fibers, an optical fiber, and an optical fiber ribbon, which have excellent storage stability and coatability.

[0009] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. (1) A resin composition for an optical fiber coloring coating according to one aspect of the present disclosure contains a photopolymerizable compound, a polydimethylsiloxane compound, a photopolymerization initiator, and titanium oxide, wherein the photopolymerizable compound contains an epoxy di(meth)acrylate, the content of the epoxy di(meth)acrylate being 30 parts by mass or more and 75 parts by mass or less per 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, the polydimethylsiloxane compound having dimethylsiloxane units and alkylene oxide units, and the molar ratio of the dimethylsiloxane units based on the total amount of the dimethylsiloxane units and the alkylene oxide units being 12 mol % or more and 80 mol % or less.

[0010] Such a resin composition can achieve both storage stability and coatability by specifying the content of epoxy di(meth)acrylate used as a photopolymerizable compound and by containing a polydimethylsiloxane compound having a specific structure.

[0011] (2) In the above (1), the polydimethylsiloxane compound may have a (meth)acryloyl group in order to further improve the storage stability of the resin composition.

[0012] (3) In the above (1) or (2), from the viewpoint of further improving the coatability of the resin composition, the viscosity of the resin composition according to this embodiment may be 800 mPa·s or more and less than 10,000 mPa·s at 25°C.

[0013] (4) In any of the above (1) to (3), from the viewpoint of adjusting the viscosity of the resin composition, the photopolymerizable compound may further contain at least one selected from the group consisting of alkylene oxide-modified di(meth)acrylates and alkylene oxide-modified tri(meth)acrylates.

[0014] (5) 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 the glass fiber and coats the glass fiber, a secondary resin layer that coats the primary resin layer, and a colored resin layer that coats the secondary resin layer, wherein the colored resin layer contains a cured product of the resin composition according to any one of (1) to (4). By applying the resin composition according to this embodiment to the colored resin layer, an optical fiber that is less susceptible to breakage or the like can be produced.

[0015] (6) 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 the glass fiber and coats the glass fiber, and a secondary resin layer that coats the primary resin layer, wherein the secondary resin layer contains a cured product of the resin composition according to any one of (1) to (4). By applying the resin composition according to this embodiment to the secondary resin layer, an optical fiber that is less susceptible to breakage or the like can be produced.

[0016] (7) An optical fiber ribbon according to an aspect of the present disclosure includes a plurality of optical fibers according to (5) or (6) arranged in parallel and coated with a ribbon resin. In such an optical fiber ribbon, color peeling does not occur when the optical fibers are removed, and the optical fibers can be easily identified.

[0017] [Details of the Embodiments of the Present Disclosure] Specific examples of resin compositions and optical fibers according to embodiments of the present disclosure 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 equivalent to 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 means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acryloyl.

[0018] (Resin Composition) The resin composition for optical fiber coloring coating according to this embodiment contains a photopolymerizable compound, a polydimethylsiloxane compound, a photopolymerization initiator, and titanium oxide, wherein the photopolymerizable compound contains epoxy di(meth)acrylate, and the content of the epoxy di(meth)acrylate is 30 parts by mass or more and 75 parts by mass or less relative to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, and the polydimethylsiloxane compound has dimethylsiloxane units and alkylene oxide units, and the molar ratio of the dimethylsiloxane units based on the total amount of the dimethylsiloxane units and the alkylene oxide units is 12 mol % or more and 80 mol % or less.

[0019] The polydimethylsiloxane compound according to this embodiment contains a dimethylsiloxane unit (—Si(CH ３ ) ２ O-) as a repeating unit, and has an alkylene oxide unit in the side chain or at the terminal.

[0020] The amount of dimethylsiloxane units (hereinafter referred to as "DMS units") and alkylene oxide units (hereinafter referred to as "RO units") contained in the polydimethylsiloxane compound varies depending on the amount of the polydimethylsiloxane compound. １It can be calculated by measuring H NMR. From the viewpoint of further improving the storage stability of the resin composition, the molar ratio of DMS units may be 14 mol% or more, 16 mol% or more, 20 mol% or more, or 25 mol% or more based on the total amount of DMS units and RO units. Furthermore, from the viewpoint of further improving compatibility with epoxy di(meth)acrylate, the molar ratio of DMS units may be 70 mol% or less, 60 mol% or less, 55 mol% or less, or 50 mol% or less based on the total amount of DMS units and RO units.

[0021] Alkylene oxides include ethylene oxide (EO) and propylene oxide (PO).

[0022] From the viewpoint of further improving the storage stability of the resin composition, the polydimethylsiloxane compound may have a (meth)acryloyl group. The polydimethylsiloxane compound may have a (meth)acryloyl group on a side chain or at an end. The (meth)acryloyl group may be bonded to an alkylene oxide unit. The polydimethylsiloxane compound having a (meth)acryloyl group can be copolymerized with a photopolymerizable compound described below. In the present embodiment, the polydimethylsiloxane compound having a (meth)acryloyl group is not included in the photopolymerizable compound. The number of (meth)acryloyl groups possessed by the polydimethylsiloxane compound may be 1 or more, 2 or more, or 6 or less, 5 or less, or 4 or less. From the viewpoint of further improving the storage stability of the resin composition, the polydimethylsiloxane compound may have 1 to 6 (meth)acryloyl groups, and the molar ratio of DMS units may be 14 mol% to 70 mol%.

[0023] From the viewpoint of further improving the storage stability of the resin composition, the content of the polydimethylsiloxane compound may be 0.5 parts by mass or more, 1.0 parts by mass or more, 1.5 parts by mass or more, or 2.0 parts by mass or more, relative to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, and may be 12.0 parts by mass or less, 10.0 parts by mass or less, 8.0 parts by mass or less, or 6.0 parts by mass or less.

[0024] The photopolymerizable compound according to this embodiment is distinguished from polydimethylsiloxane compounds having (meth)acryloyl groups in that it does not have a dimethylsiloxane skeleton. The photopolymerizable compound contains an epoxy di(meth)acrylate, which can increase the strength of the colored resin layer. As the epoxy di(meth)acrylate, a reaction product of a diglycidyl ether compound having a bisphenol skeleton and a compound having a (meth)acryloyl group, such as (meth)acrylic acid, can be used.

[0025] Examples of epoxy di(meth)acrylates include (meth)acrylic acid adducts of bisphenol A diglycidyl ether, (meth)acrylic acid adducts of bisphenol AF diglycidyl ether, and (meth)acrylic acid adducts of bisphenol F diglycidyl ether.

[0026] The content of the epoxy di(meth)acrylate may be 30 parts by mass or more, 35 parts by mass or more, 40 parts by mass or more, or 42 parts by mass or more, relative to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, from the viewpoint of improving the storage stability of the resin composition, and may be 75 parts by mass or less, 72 parts by mass or less, 70 parts by mass or less, or 69 parts by mass or less, from the viewpoint of improving the coatability of the resin composition.

[0027] The photopolymerizable compound according to this embodiment may further contain a photopolymerizable compound (hereinafter referred to as a "monomer") other than epoxy di(meth)acrylate.

[0028] The monomer may be a monofunctional monomer having one polymerizable group or a polyfunctional monomer having two or more polymerizable groups. Two or more types of monomers may be used in combination.

[0029] Examples of monofunctional monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, isoamyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. (Meth)acrylate monomers such as acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, 3-phenoxybenzyl acrylate, phenoxydiethylene glycol acrylate, phenoxypolyethylene glycol acrylate, 4-tert-butylcyclohexanol acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, nonylphenol polyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, and isobornyl (meth)acrylate; (meth)acrylic acid, (meth)acrylic acid dimer, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, ω-carboxymethyl (meth)acrylate, Carboxy group-containing monomers such as carboxy-polycaprolactone (meth)acrylate; heterocycle-containing monomers such as N-(meth)acryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, 3-(3-pyridine)propyl (meth)acrylate, and cyclic trimethylolpropane formal acrylate; maleimide-based monomers such as maleimide, N-cyclohexylmaleimide, and N-phenylmaleimide;Amide-based monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, and N-methylolpropane(meth)acrylamide; aminoalkyl (meth)acrylate-based monomers such as aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate; and succinimide-based monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide.

[0030] Examples of polyfunctional monomers include polyethylene glycol di(meth)acrylate, isocyanuric acid ethylene oxide modified di(meth)acrylate, ethylene oxide modified bisphenol F di(meth)acrylate, ethylene oxide modified bisphenol A di(meth)acrylate, polypropylene glycol di(meth)acrylate, propylene oxide modified bisphenol A di(meth)acrylate, propylene oxide modified neopentyl glycol di(meth)acrylate, polytetraethylene glycol di(meth)acrylate, ) acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,20-eicosanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, iso Pentyldiol di(meth)acrylate, 3-ethyl-1,8-octanediol di(meth)acrylate; 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 ) acrylate, pentaerythritol polyethoxytetra(meth)acrylate, pentaerythritol polypropoxytetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified tris[(meth)acryloyloxyethyl]isocyanurate.

[0031] The photopolymerizable compound according to this embodiment may contain an alkylene oxide-modified polyfunctional monomer in order to adjust the Young's modulus of the resin layer. The alkylene oxide-modified polyfunctional monomer may have at least one selected from the group consisting of an ethylene oxide (EO) chain and a propylene oxide (PO) chain. The ethylene oxide chain can be represented as "(EO)n" and the propylene oxide chain can be represented as "(PO)n". n is an integer of 1 or greater, and may be 2 or greater or 3 or greater, or may be 30 or less, 25 or less, or 20 or less.

[0032] From the viewpoint of adjusting the viscosity of the resin composition, the photopolymerizable compound may further contain at least one selected from the group consisting of alkylene oxide-modified di(meth)acrylates and alkylene oxide-modified tri(meth)acrylates.

[0033] Examples of alkylene oxide-modified di(meth)acrylates include polyethylene glycol di(meth)acrylate, isocyanuric acid ethylene oxide-modified di(meth)acrylate, ethylene oxide-modified bisphenol F di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate polypropylene glycol di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, and propylene oxide-modified neopentyl glycol di(meth)acrylate.

[0034] Examples of alkylene oxide-modified tri(meth)acrylates include 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, and pentaerythritol tri(meth)acrylate.

[0035] The photopolymerization initiator can be appropriately selected from known radical photopolymerization initiators. Examples of the photopolymerization initiator include 1-hydroxycyclohexylphenyl ketone (Omnirad 184, manufactured by IGM Resins), 2,2-dimethoxy-2-phenylacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one (Omnirad 907, manufactured by IGM Resins), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO, manufactured by IGM Resins), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, manufactured by IGM Resins).

[0036] The content of the photopolymerization initiator may be 1 part by mass or more and 10 parts by mass or less, 2 parts by mass or more and 8 parts by mass or less, or 3 parts by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound.

[0037] The resin composition may further contain a silane coupling agent, a leveling agent, an antifoaming agent, an antioxidant, a sensitizer, and the like.

[0038] The silane coupling agent is not particularly limited as long as it does not interfere with the curing of the resin composition. Examples of the silane coupling agent include tetramethyl silicate, tetraethyl silicate, mercaptopropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, dimethoxydimethylsilane, diethoxydimethylsilane, 3-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)- Examples include 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-trimethoxysilylpropyldimethylthiocarbamyltetrasulfide, and γ-trimethoxysilylpropylbenzothiazyltetrasulfide.

[0039] From the viewpoint of coloring the resin layer, the resin composition according to this embodiment may further contain titanium oxide particles. As the titanium oxide particles, surface-treated titanium oxide particles may be used. The surface-treated titanium oxide particles are titanium oxide particles that have been surface-treated with an inorganic substance and have excellent dispersibility in the resin composition.

[0040] Examples of inorganic substances used for surface treatment include aluminum oxide, silicon dioxide, and zirconium dioxide. When the surface-treated titanium oxide particles have a surface treatment layer containing at least one selected from the group consisting of aluminum oxide, silicon dioxide, and zirconium dioxide, dispersibility can be further improved. The surface treatment layer may be formed on at least a portion of the surface of the titanium oxide, or may be formed on the entire surface of the titanium oxide. The surface treatment layer is formed by surface treatment of the titanium oxide.

[0041] The amount of the surface treatment layer in the surface-treated titanium oxide particles may be 1% by mass or more, 1.5% by mass or more, or 2% by mass or more from the viewpoint of improving dispersibility, and may be 10% by mass or less, 9% by mass or less, or 8% by mass or less from the viewpoint of improving hiding power. The amount of the surface treatment layer can be calculated by measuring the amounts of titanium element and inorganic elements other than titanium contained in the surface-treated titanium oxide particles using inductively coupled plasma mass spectrometry (ICP-MS).

[0042] The average primary particle size of the surface-treated titanium oxide particles may be 300 nm or less, 295 nm or less, or 290 nm or less from the viewpoint of improving the lateral pressure resistance of the coating resin layer. The average primary particle size of the surface-treated titanium oxide particles may be 100 nm or more, 150 nm or more, or 200 nm or more, or 200 nm or more but 300 nm or less from the viewpoint of improving hiding power. The average primary particle size can be measured, for example, by image analysis of electron microscope photographs, a light scattering method, a BET method, or the like.

[0043] The content of the surface-treated titanium oxide particles may be 0.6 mass% or more, 1 mass% or more, 2 mass% or more, or 3 mass% or more based on the total amount of the resin composition from the viewpoint of improving the visibility of the resin layer. The content of the surface-treated titanium oxide particles may be 20 mass% or less, 15 mass% or less, 10 mass% or less, or 8 mass% or less based on the total amount of the resin composition from the viewpoint of improving the curability of the resin composition.

[0044] The viscosity at 25°C of the resin composition according to this embodiment may be 800 mPa·s or more, 1000 mPa·s or more, 1500 mPa·s or more, or 2000 mPa·s or more from the viewpoint of further improving storage stability, and may be less than 10000 mPa·s, 9000 mPa·s or less, or 8500 mPa·s or less from the viewpoint of further improving coatability.

[0045] The resin composition according to this embodiment is applied at 900 mJ / cm ２ More than 1100mJ / cm ２ A resin layer having excellent toughness can be formed when the elongation at break of a resin film cured with the following integrated light amount is 6% or more and 50% or less at 23° C. The elongation at break of the resin film may be 6.5% or more, 7% or more, or 10% or more, or may be 45% or less, 40% or less, or 30% or less.

[0046] From the viewpoint of improving the single-fiber separation property of the optical fiber, the Young's modulus of the resin film may be 500 MPa or more, 600 MPa or more, or 700 MPa or more at 23° C. From the viewpoint of forming a resin layer with excellent toughness, the Young's modulus of the resin film may be 1600 MPa or less, 1500 MPa or less, or 1450 MPa or less at 23° C.

[0047] The resin composition according to the present embodiment can be suitably used as a colored coating material for optical fibers. By forming the outermost layer of the coating resin layer using a colored coating material containing the resin composition according to the present embodiment, the single-fiber separation property of the optical fiber can be improved.

[0048] (Optical Fiber) Fig. 1 is a schematic cross-sectional view showing the configuration of an optical fiber according to one embodiment. As shown in Fig. 1, the optical fiber 1 includes a glass fiber 10 and a coating resin layer 20 that contacts the glass fiber 10 and covers the outer periphery of the glass fiber 10.

[0049] The glass fiber 10 is a light-guiding optical transmission body that transmits light introduced into the optical fiber 1. The glass fiber 10 is a glass member, and is made of, for example, silica (SiO ２The glass fiber 10 is constructed using SiO 2 glass as a base material (main component). The glass fiber 10 includes a core 12 and a cladding 14 that covers the core 12. The glass fiber 10 transmits light introduced into the optical fiber 1. The core 12 is provided, for example, in a region that includes the central axis of the glass fiber 10. The core 12 is made of, for example, pure SiO 2 ２ Glass or SiO ２ Glass with GeO ２ The cladding 14 is provided in the region surrounding the core 12. The cladding 14 has a refractive index lower than that of the core 12. The cladding 14 is made of, for example, pure SiO ２ Glass or SiO2 doped with fluorine ２ The glass fiber 10 is made of glass and has an outer diameter of about 100 μm to 125 μm, and a core 12 constituting the glass fiber 10 has a diameter of about 7 μm to 15 μm.

[0050] The coating resin layer 20 is an ultraviolet-curable resin layer that covers the clad 14. The coating resin layer 20 includes a primary resin layer 22 that coats the outer periphery of the glass fiber 10 and a secondary resin layer 24 that coats the outer periphery of the primary resin layer 22. The primary resin layer 22 is in contact with the outer periphery of the clad 14 and coats the entire clad 14. The secondary resin layer 24 is in contact with the outer periphery of the primary resin layer 22 and coats the entire primary resin layer 22. The thickness of the primary resin layer 22 is, for example, 10 μm or more and 50 μm or less. The thickness of the secondary resin layer 24 is, for example, 10 μm or more and 40 μm or less.

[0051] The resin composition according to this embodiment can be applied to the secondary resin layer 24. The secondary resin layer 24 can be formed by curing the resin composition. By including a cured product of the resin composition according to this embodiment, the secondary resin layer 24 can improve the single-fiber separation properties of the optical fiber.

[0052] The coating resin layer 20 may further include a colored resin layer 26 that coats the outer periphery of the secondary resin layer 24. Fig. 2 is a schematic cross-sectional view showing the configuration of an optical fiber according to one embodiment. As shown in Fig. 2, the optical fiber 1A of this embodiment includes a glass fiber 10 and a coating resin layer 20 that contacts the glass fiber 10 and covers the outer periphery of the glass fiber 10. The coating resin layer 20 includes a primary resin layer 22, a secondary resin layer 24, and a colored resin layer 26. The thickness of the colored resin layer 26 is, for example, not less than 3 µm and not more than 10 µm.

[0053] The resin composition according to this embodiment can be applied to the colored resin layer 26. The colored resin layer 26 can be formed by curing the resin composition. By including a cured product of the resin composition according to this embodiment, the colored resin layer 26 can improve the single-core separation property of the optical fiber. The secondary resin layer 24 in the fiber 1A may be formed using a conventionally known resin composition, and can be formed, for example, by curing a resin composition containing urethane (meth)acrylate, a monomer, and a photopolymerization initiator.

[0054] The primary resin layer 22 can be formed by curing a resin composition containing, for example, urethane (meth)acrylate, a monomer, a photopolymerization initiator, and a silane coupling agent. The resin composition for the primary resin layer can be formed using a conventionally known technique.

[0055] (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.

[0056] 3 is a schematic cross-sectional view showing an optical fiber ribbon according to the present embodiment. The optical fiber ribbon 100 includes a plurality of optical fibers 1A and a connecting resin layer 40 in which the optical fibers 1A are coated with a ribbon resin and connected. In FIG. 3, four optical fibers are shown as an example, but the number is not particularly limited.

[0057] The ribbon resin may be a resin material generally known as a ribbon material. From the viewpoint of preventing damage to the optical fiber and facilitating separation, 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.

[0058] By using the above-mentioned optical fiber, the optical fiber ribbon of this embodiment does not experience color peeling when removing the connecting resin layer from the optical fiber ribbon to extract the optical fiber, and the optical fiber can be easily identified.

[0059] 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.

[0060] [Resin Composition for Colored Resin Layer] (Polydimethylsiloxane Compound) The polydimethylsiloxane compounds shown in Table 1 were prepared. The molar ratio of DMS units in the polydimethylsiloxane compound (DMS units / (DMS units+RO units)) was １ H NMR was measured and the ratio was calculated from the ratio of hydrogen atoms in the DMS unit to hydrogen atoms in the RO unit. １ The measurement conditions for H NMR are as follows: Measurement device: Fourier transform nuclear magnetic resonance device (Bruker Biospin's "Ascend500+AVANCE III HD") Probe: 5 mm BBFO BB / 19F-1H / D probe Measurement solvent: chloroform-d Sample concentration: 20% (mL / mL) Measurement nuclide: 1H Measurement method: 1D Number of accumulations: 128

[0061]

[0062] (Photopolymerizable Compound) Examples of the photopolymerizable compound include bisphenol A epoxy diacrylate (EA), polypropylene glycol diacrylate (PPGDA), and EO-modified trimethylolpropane triacrylate (TMP(EO)). ３ TA), EO-modified bisphenol A diacrylate (BPA(EO)３０ DA) was prepared.

[0063] As photopolymerization initiators, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO) and 1-hydroxycyclohexylphenyl ketone (Omnirad 184) were prepared.

[0064] As titanium oxide particles, aluminum oxide (Al ２ O ３ The surface-treated titanium oxide particles had an average primary particle size of 200 to 300 nm, and the Al content calculated by ICP-MS was ２ O ３ The amount was 2.5% by mass.

[0065] Resin compositions were prepared by mixing the polydimethylsiloxane compound, photopolymerizable compound, and photopolymerization initiator in the amounts (parts by mass) shown in Table 2 or Table 3, and then mixing them so that the content of the surface-treated titanium oxide particles in the resin composition was 5 mass%. Test Examples 1 to 11 correspond to Examples, and Test Examples 12 to 15 correspond to Comparative Examples.

[0066] (Viscosity) The viscosity of the resin composition at 25°C was 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 was carried out under the following conditions.

[0067] (Storage stability) After preparing the resin composition, it was stored in a thermostatic chamber at 30° C. If there was no change in the appearance of the resin composition after 30 days, it was evaluated as "A." If phase separation such as precipitation occurred in the resin composition within 15 days, it was evaluated as "B." If phase separation such as precipitation occurred in the resin composition within 7 days, it was evaluated as "C."

[0068] (Young's modulus) After applying the resin composition onto a polyethylene terephthalate (PET) film using a spin coater, the resin composition was irradiated with 1000±100 mJ / cm using an electrodeless UV lamp system (Heraeus VPS600 (D bulb)). ２The resin layer was peeled off from the PET film to obtain a resin film.

[0069] The resin film was punched into a dumbbell shape conforming to JIS K 7127 Type 5 and stretched using a tensile tester at 23±2°C, 50±10% RH, a tension rate of 1 mm / min, and a gauge length of 25 mm to obtain a stress-strain curve. Young's modulus was determined using the 2.5% secant line.

[0070] (Resin composition for primary resin layer) A urethane acrylate oligomer obtained by reacting polypropylene glycol having a molecular weight of 4000, isophorone diisocyanate, hydroxyethyl acrylate, and methanol was prepared. 75 parts by mass of this urethane acrylate oligomer, 12 parts by mass of nonylphenol EO-modified acrylate, 6 parts by mass of N-vinyl caprolactam, 2 parts by mass of 1,6-hexanediol diacrylate, 1 part by mass of Omnirad TPO, and 1 part by mass of 3-mercaptopropyltrimethoxysilane were mixed to prepare resin composition P.

[0071] (Resin composition for secondary resin layer) Resin composition S was prepared by mixing 40 parts by mass of a urethane acrylate oligomer which is a reaction product of polypropylene glycol having a molecular weight of 600, 2,4-tolylene diisocyanate, and 2-hydroxyethyl acrylate, 35 parts by mass of isobornyl acrylate, 24 parts by mass of epoxy acrylate which is an acrylic acid adduct of bisphenol A diglycidyl ether, 1 part by mass of Omnirad TPO, and 1 part by mass of Omnirad 184.

[0072] [Fabrication of Optical Fiber] An optical fiber was fabricated by forming a 17.5 μm thick primary resin layer on the outer periphery of a 125 μm diameter glass fiber composed of a core and cladding using resin composition P, and then forming a 15 μm thick secondary resin layer on the outer periphery of the primary resin layer using resin composition S. Next, the optical fiber was temporarily wound up, and then a 5 μm thick colored resin layer was formed on the outer periphery of the secondary resin layer using the resin compositions of Test Examples 1 to 7 while the optical fiber was being re-wound using a coloring machine, thereby fabricating an optical fiber with a diameter of 200 μm and a colored resin layer (hereinafter referred to as "colored optical fiber"). The linear speed during the formation of each resin layer was 1500 m / min.

[0073] (Coating Property) The coating property of the resin composition was evaluated by checking whether or not the optical fiber had any breaks. When there were no breaks in the optical fiber, it was rated as "OK", and when there were breaks in the optical fiber, it was rated as "NG".

[0074]

[0075]

[0076] REFERENCE SIGNS LIST 1, 1A... Optical fiber 10... Glass fiber 12... Core 14... Cladding 20... Coating resin layer 22... Primary resin layer 24... Secondary resin layer 26... Colored resin layer 40... Connecting resin layer 100... Optical fiber ribbon

Claims

1. The composition contains a photopolymerizable compound, a polydimethylsiloxane compound, a photopolymerization initiator, and titanium oxide, the photopolymerizable compound includes an epoxy di(meth)acrylate, the content of the epoxy di(meth)acrylate is 30 parts by mass or more and 75 parts by mass or less with respect to 100 parts by mass of the total amount of the photopolymerizable compound and the polydimethylsiloxane compound, the polydimethylsiloxane compound has dimethylsiloxane units and alkylene oxide units, and the molar ratio of the dimethylsiloxane units based on the total amount of the dimethylsiloxane units and the alkylene oxide units is 12 mol % or more and 80 mol % or less.

2. The resin composition according to claim 1 , wherein the polydimethylsiloxane compound has a (meth)acryloyl group.

3. The resin composition according to claim 1, having a viscosity of 800 mPa·s or more and less than 10,000 mPa·s at 25°C.

4. The resin composition according to claim 1 , wherein the photopolymerizable compound further comprises at least one selected from the group consisting of alkylene oxide-modified di(meth)acrylates and alkylene oxide-modified tri(meth)acrylates.

5. a glass fiber including a core and a cladding; a primary resin layer that is in contact with and covers the glass fiber; a secondary resin layer that covers the primary resin layer; A colored resin layer that covers the secondary resin layer, An optical fiber, wherein the colored resin layer comprises a cured product of the resin composition according to any one of claims 1 to 4.

6. a glass fiber including a core and a cladding; a primary resin layer that is in contact with and covers the glass fiber; A secondary resin layer that covers the primary resin layer, An optical fiber, wherein the secondary resin layer comprises a cured product of the resin composition according to claim 1 .

7. An optical fiber ribbon comprising a plurality of the optical fibers according to claim 5 arranged in parallel and coated with a ribbon resin.

8. 7. An optical fiber ribbon comprising a plurality of the optical fibers according to claim 6 arranged in parallel and coated with a ribbon resin.