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

Abstract

A resin composition for primary coating of an optical fiber contains: a photopolymerizable compound including a urethane (meth)acrylate containing a reaction product of a polypropylene polyol having a number average molecular weight of 8,000 or more and 20,000 or less and an isocyanate group-containing (meth)acrylate; and a photopolymerization initiator.

Description

Technical Field

[0001] This disclosure relates to resin compositions for primary coating of optical fibers, optical fibers, methods for manufacturing optical fibers, optical fiber ribbons, and optical fiber cables.

[0002] This application claims priority based on Japanese Application No. 2021-016587, filed on February 4, 2021, and invokes all the contents set forth in that Japanese application. Background Technology

[0003] In recent years, the demand for high-density cables with increased fiber optic fill density has increased for data center applications. Typically, optical fibers have a resin coating layer that protects the glass fiber, which acts as the light transmission medium. This resin coating layer typically consists of two layers: a primary resin layer in contact with the glass fiber and a secondary resin layer formed on top of the primary resin layer. When the fiber fill density increases, external forces (lateral pressure) are applied to the fiber, easily increasing microbending loss. To improve the microbending resistance of optical fibers, it is known to reduce the Young's modulus of the primary resin layer and increase the Young's modulus of the secondary resin layer. For example, Patent Documents 1-5 describe resin compositions for a primary coating containing urethane (meth)acrylate, a reaction product of a polyol, diisocyanate, and a hydroxyl-containing (meth)acrylate.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-197163

[0007] Patent Document 2: Japanese Patent Application Publication No. 2012-111674

[0008] Patent Document 3: Japanese Patent Application Publication No. 2013-136783

[0009] Patent Document 4: Japanese Patent Publication No. 2013-501125

[0010] Patent Document 5: Japanese Patent Application Publication No. 2014-114208 Summary of the Invention

[0011] One aspect of this disclosure relates to a resin composition for the primary coating of an optical fiber comprising: a photopolymerizable compound comprising a urethane (meth)acrylate containing a reaction product of a polypropylene polyol having a number average molecular weight of 8,000 to 20,000 and an isocyanate-containing (meth)acrylate; and a photopolymerization initiator. Attached Figure Description

[0012] [Figure 1 ] Figure 1 This is a schematic cross-sectional view showing an example of the optical fiber involved in this embodiment.

[0013] [ Figure 2 ] Figure 2 This is a schematic cross-sectional view showing an embodiment of an optical fiber strip.

[0014] [ Figure 3 ] Figure 3 This is a schematic cross-sectional view showing an embodiment of an optical fiber strip.

[0015] [ Figure 4 ] Figure 4 This is a plan view showing the appearance of an optical fiber strip according to one embodiment.

[0016] [ Figure 5 ] Figure 5 This is a schematic cross-sectional view showing an embodiment of an optical fiber cable.

[0017] [ Figure 6 ] Figure 6 This is a schematic cross-sectional view showing an embodiment of an optical fiber cable. Detailed Implementation

[0018] [The problem this disclosure aims to solve]

[0019] As the Young's modulus decreases, the tensile strength of the primary coating resin composition tends to decrease, and defects (voids) will be generated in the primary resin layer, which can easily lead to increased transport loss, especially at low temperatures.

[0020] The purpose of this disclosure is to provide a resin composition that has both low Young's modulus and high breaking strength, capable of forming a primary coating resin layer suitable for optical fibers, and an optical fiber with excellent microbending resistance and low-temperature properties.

[0021] [The Effects of This Disclosure]

[0022] According to this disclosure, a resin composition capable of forming a primary coating resin layer suitable for optical fibers can be provided, which has both low Young's modulus and high breaking strength, as well as optical fibers with excellent microbending resistance and low-temperature properties.

[0023] [Description of embodiments of this disclosure]

[0024] First, embodiments of the present disclosure will be listed and described. One aspect of the present disclosure relates to a primary coating resin composition for optical fibers comprising: a photopolymerizable compound comprising urethane (meth)acrylate (A) containing a reaction product of a polypropylene polyol having a number average molecular weight of 8,000 to 20,000 and an isocyanate-containing (meth)acrylate; and a photopolymerization initiator.

[0025] Such a resin composition can have both low Young's modulus and high tensile strength, and will not produce defects in the primary resin layer. Therefore, it can form a primary coating resin layer suitable for optical fibers, which can improve the microbending resistance and low temperature characteristics of optical fibers.

[0026] From the viewpoint of improving the adhesion between glass fiber and primary resin layer, urethane (meth)acrylate (A) may further include polypropylene polyol with a number average molecular weight of 8,000 to 20,000, isocyanate-containing (meth)acrylate, and reaction products of isocyanate-containing silane compounds.

[0027] To further improve the fracture strength of the primary resin layer, the photopolymerizable compound may further include polypropylene polyol, diisocyanate, and urethane (meth)acrylate (B), which are reaction products of hydroxyl-containing (meth)acrylates, as well as polypropylene polyol, diisocyanate, and urethane (meth)acrylate, which have a number average molecular weight of 2,000 to 20,000.

[0028] Considering the ease of adjusting the Young's modulus of the primary resin layer, the number-average molecular weight of the polypropylene polyol used in urethane (meth)acrylate (B) can be between 6,000 and 20,000.

[0029] To further improve the fracture strength of the primary resin layer, it may further include reaction products containing polyoxyalkylene monoalkyl ethers, diisocyanates, and hydroxyl-containing (meth)acrylates; or urethane (meth)acrylates (C) that are reaction products of polyoxyalkylene monoalkyl ethers and isocyanate-containing (meth)acrylates.

[0030] From the perspective of adjusting to the Young's modulus suitable for the primary resin layer, the number average molecular weight of polyoxyalkylene monoalkyl ethers can be between 2000 and 10000.

[0031] One aspect of this disclosure relates to an optical fiber comprising: a glass fiber having a core and a cladding; a primary resin layer in contact with and covering the glass fiber; and a secondary resin layer covered by the primary resin layer, wherein the primary resin layer comprises a cured product of the aforementioned resin composition. Such an optical fiber does not produce defects in the primary resin layer, thereby exhibiting excellent microbending resistance and low-temperature characteristics.

[0032] One aspect of this disclosure relates to a method for manufacturing optical fibers, comprising: a coating step of coating the aforementioned resin composition onto the outer periphery of a glass fiber containing a core and a cladding; and a curing step of curing the resin composition by irradiation with ultraviolet light after the coating step. This enables the production of optical fibers with excellent micro-bending resistance and low-temperature characteristics.

[0033] One aspect of this disclosure involves an optical fiber ribbon comprising multiple optical fibers arranged side-by-side, and the ribbon being coated with resin. Such an optical fiber ribbon exhibits excellent micro-bending resistance and low-temperature performance, and can be densely packed within an optical fiber cable.

[0034] One embodiment of this disclosure relates to an optical fiber cable that incorporates the aforementioned optical fiber ribbon within the cable. The optical fiber cable of this disclosure may also incorporate multiple of the aforementioned optical fibers within the cable. Optical fiber cables incorporating the optical fibers or optical fiber ribbons of this embodiment exhibit excellent micro-bending resistance and low-temperature performance.

[0035] [Details of the embodiments disclosed herein]

[0036] Specific examples of the resin composition and optical fiber involved in this embodiment will be described with reference to the accompanying drawings as needed. It should be noted that this disclosure is not limited to these examples, but is represented by the claims, and is intended to include all variations in the same sense and scope as the claims. In the following description, the same symbols are used to denote the same elements in the description of the drawings, and repeated descriptions are omitted. In this specification, (meth)acrylate means acrylate or the corresponding methacrylate, and the same applies to other similar expressions such as (meth)acryloyl.

[0037] (Resin Composition)

[0038] The resin composition according to this embodiment contains: a photopolymerizable compound comprising urethane (meth)acrylate (A), which is a reaction product of a polypropylene polyol with a number average molecular weight (Mn) of 8000 to 20000 and an isocyanate-containing (meth)acrylate; and a photopolymerization initiator. The urethane (meth)acrylate (A) has propylene oxide chains from the polypropylene polyol with a Mn of 8000 to 20000 and (meth)acryloyl groups from the isocyanate-containing (meth)acrylate. By using urethane (meth)acrylate (A), both low Young's modulus and high tensile strength of the primary resin layer can be achieved.

[0039] From the viewpoint of adjusting the balance between Young's modulus and fracture strength of the primary resin layer to an appropriate range, the Mn of the polypropylene polyol constituting urethane (meth)acrylate (A) can be 9000 to 19500, 10000 to 19000, or 11000 to 18500.

[0040] Polypropylene polyols can be difunctional polypropylene polyols with two hydroxyl groups (polypropylene glycol), trifunctional polypropylene polyols with three hydroxyl groups (polyoxypropylene triol), or mixtures of polypropylene glycol and polyoxypropylene triol.

[0041] Examples of isocyanate-containing (meth)acrylates include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-(2-isocyanate ethoxy)ethyl methacrylate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, and 1,1-(bismethacryloyloxymethyl)ethyl isocyanate. From a reactivity point of view, 2-acryloyloxyethyl isocyanate is preferred.

[0042] From the viewpoint of improving the adhesion between the glass fiber and the primary resin layer, urethane (meth)acrylate (A) can further comprise a reaction product of a polypropylene polyol with an Mn of 8000 to 20000, an isocyanate-containing (meth)acrylate, and an isocyanate-containing silane compound. That is, in addition to the oxypropylene chain and (meth)acryloyl group, urethane (meth)acrylate (A) may also have an alkoxysilyl group derived from an isocyanate-containing silane compound.

[0043] Examples of silane compounds containing isocyanate groups include 3-(triethoxysilyl)propyl isocyanate and 3-(trimethoxysilyl)propyl isocyanate.

[0044] The urethane (meth)acrylate (A) is obtained by reacting a polypropylene polyol, an isocyanate-containing (meth)acrylate, and an isocyanate-containing silane compound as needed.

[0045] The urethane (meth)acrylate (A) may comprise a mixture of urethane (meth)acrylates represented by formulas (1) to (3) below. In formulas (1) to (3), AI represents a residue of (meth)acrylate containing an isocyanate group, U represents a urethane bond, PO represents a residue of polypropylene polyol, OH represents a hydroxyl group, and SC represents a residue of a silane compound containing an isocyanate group.

[0046] AI-U-PO-U-AI(1)

[0047] AI-U-PO-OH(2)

[0048] AI-U-PO-SC(3)

[0049] In the preparation of urethane acrylate (A), without the addition of a silane compound containing an isocyanate group, urethane (meth) acrylate represented by (1), or a mixture of urethane (meth) acrylate represented by (1) and urethane (meth) acrylate represented by (2) is generated.

[0050] The molar ratio of NCO to OH (NCO / OH) when polypropylene polyol reacts with isocyanate-containing (meth)acrylate is preferably 0.4 to 1.1, more preferably 0.5 to 1.0. The molar ratio of NCO to OH (NCO / OH) when polypropylene polyol reacts with isocyanate-containing silane compounds is preferably 0.01 to 0.5, more preferably 0.03 to 0.3.

[0051] From the viewpoint of obtaining a Young's modulus suitable for the primary resin layer, the Mn of urethane (meth)acrylate (A) can be 10,000 to 50,000, 12,000 to 40,000, or 14,000 to 30,000. The Mn of the urethane (meth)acrylate involved in this embodiment can be determined by GPC (gel permeation chromatography).

[0052] From the perspective of easily improving the tensile strength of the primary resin layer, photopolymerizable compounds can include urethane (meth)acrylate (B) as a reaction product of polypropylene polyol with an Mn of 2000 to 20000, diisocyanate, and hydroxyl-containing (meth)acrylate. Uramel (meth)acrylate (B) has an oxypropylene chain from the polypropylene polyol with an Mn of 2000 to 20000 and a (meth)acryloyl group from the hydroxyl-containing (meth)acrylate.

[0053] From the viewpoint of further improving the tensile strength of the primary resin layer, the Mn of the polypropylene polyol constituting urethane (meth)acrylate (B) can be 6000 to 20000, 8000 to 19000, or 10000 to 18500. From the perspective of easily adjusting the Young's modulus and tensile strength of the primary resin layer, polypropylene glycol is preferred as the polypropylene polyol.

[0054] Examples of diisocyanates include: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, phenyl diisocyanate, hydrogenated phenyl diisocyanate, 1,5-naphthalene diisocyanate, norbornene diisocyanate, 1,5-pentamethylene diisocyanate, tetramethylphenyl diisocyanate, and trimethylhexamethylene diisocyanate.

[0055] Examples of hydroxyl-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-phenylphenol propyl (meth)acrylate, 2-hydroxy-3-methylpropenyl acrylate, trimethylolpropane di(meth)acrylate, and pentaerythritol tri(meth)acrylate. From a reactivity point of view, 2-hydroxyethyl acrylate is preferred.

[0056] Methods for preparing urethane (meth)acrylate (B) include, for example: reacting a polypropylene polyol with a diisocyanate and then with a hydroxyl-containing (meth)acrylate; reacting a diisocyanate with a hydroxyl-containing (meth)acrylate and then with a polypropylene polyol; and reacting a hydroxyl-containing (meth)acrylate with a polypropylene polyol and a diisocyanate simultaneously.

[0057] The urethane (meth)acrylate (B) may contain urethane (meth)acrylate represented by the following formula (4). In formula (4), AH represents a hydroxyl-containing (meth)acrylate residue, U represents a urethane bond, I represents a diisocyanate residue, PO represents a polypropylene polyol residue, and n is an integer greater than or equal to 1.

[0058] AH-(UIU-PO)nUIU-AH(4)

[0059] The urethane acrylate (B) sometimes contains, as a byproduct, urethane (meth) acrylate represented by the following formula (5).

[0060] AH-UIU-AH(5)

[0061] The molar ratio of NCO to OH (NCO / OH) during the reaction of polypropylene glycol with diisocyanate is preferably 1.1 to 4.0, more preferably 1.2 to 3.5, and even more preferably 1.4 to 3.0.

[0062] From the viewpoint of obtaining a Young's modulus suitable for the primary resin layer, the Mn of urethane (meth)acrylate (B) can be 10,000 to 50,000, 15,000 to 45,000, or 20,000 to 40,000.

[0063] From the perspective of easily improving fracture strength, photopolymerizable compounds can include urethane (meth)acrylates (C) as reaction products of polyoxyalkylene monoalkyl ethers, diisocyanates, and hydroxyl-containing (meth)acrylates; or as reaction products of polyoxyalkylene monoalkyl ethers and isocyanate-containing (meth)acrylates. Uramel (meth)acrylates (C) are monofunctional urethane (meth)acrylates having one (meth)acryloyl group.

[0064] A monofunctional urethane (meth)acrylate (C1) that is a reaction product of a polyoxyalkylene monoalkyl ether, a diisocyanate, and a hydroxyl-containing (meth)acrylate can be represented by the following formula (6). In formula (6), AH represents a residue of the hydroxyl-containing (meth)acrylate, U represents a urethane bond, I represents a residue of the diisocyanate, and P1 represents a residue of the polyoxyalkylene monoalkyl ether. The urethane (meth)acrylate (C1) has a (meth)acryloyl group from the hydroxyl-containing (meth)acrylate and an alkoxy group from the polyoxyalkylene monoalkyl ether.

[0065] AH-UIU-P1(6)

[0066] Methods for synthesizing urethane (meth)acrylates (C1) include, for example: reacting a polyoxyalkylene monoalkyl ether with a diisocyanate and then with a hydroxyl-containing (meth)acrylate; reacting a diisocyanate with a hydroxyl-containing (meth)acrylate and then with a polyoxyalkylene monoalkyl ether; and reacting a hydroxyl-containing (meth)acrylate with both a polyoxyalkylene monoalkyl ether and a diisocyanate simultaneously.

[0067] The urethane (meth)acrylate (C2), as a reaction product of a polyoxyalkylene monoalkyl ether and an isocyanate-containing (meth)acrylate, can be represented by formula (7). In formula (7), AI represents the residue of the isocyanate-containing (meth)acrylate, U represents the urethane bond, and P1 represents the residue of the polyoxyalkylene monoalkyl ether. The urethane (meth)acrylate (C2) has a (meth)acryloyl group from the isocyanate-containing (meth)acrylate and an alkoxy group from the polyoxyalkylene monoalkyl ether.

[0068] AI-U-P1(7)

[0069] Polyoxyalkylene monoalkyl ethers are compounds having an alkylene oxide, an alkoxy group, and a hydroxyl group. Examples of polyoxyalkylene monoalkyl ethers included in this embodiment include: polyoxyethylene oleyl ether, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene octadecyl ether, and polyoxyethylene alkyl (C 12~C 14 Ethers, polyoxyethylene tridecyl ether, polyoxyethylene tetradecyl ether, polyoxyethylene isooctadecyl ether, polyoxyethylene octyl dodecyl ether, polyoxyethylene cholesterol ether, polyoxyethylene butyl ether, polyoxyethylene tetradecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene octadecyl ether, polyoxyethylene lanolin ether, polyoxyethylene polyoxyethylene butyl ether, polyoxyethylene polyoxyethylene dodecyl ether, polyoxyethylene polyoxyethylene hexadecyl ether, polyoxyethylene polyoxyethylene octadecyl ether, and polyoxyethylene polyoxyethylene decyl tetradecyl ether.

[0070] From the viewpoint of compatibility of the primary resin composition, polyoxyalkylene monoalkyl ether is preferably polyoxypropylene monobutyl ether.

[0071] From the viewpoint of obtaining a suitable Young's modulus for the primary resin layer, the number average molecular weight of the polyoxyalkylene monoalkyl ether is preferably 2,000 or more and 10,000 or less, can be 2,100 or more or 2,200 or more, or can be 8,000 or less or 7,000 or less.

[0072] The Mn of polypropylene polyols and polyoxyalkylene monoalkyl ethers can be determined by measuring the OH value according to JIS K0070 and calculated according to the following formula. Polypropylene polyols have 2 or 3 functional groups, while polyoxyalkylene monoalkyl ethers have 1 functional group.

[0073] Mn = 56.1 × number of functional groups × 1000 / hydroxyl value

[0074] From the perspective of easily improving the tensile strength of the primary resin layer, polyoxyalkylene monoalkyl ethers can contain high molecular weight components with a molecular weight of 50,000 or more, thus exhibiting an asymmetric molecular weight distribution with a tail on the high molecular weight side. Examples of such polyoxyalkylene monoalkyl ethers include, for instance, the trade names "Acrobute MB-90" and "Acrobute MB-52" manufactured by Nippon Oil Co., Ltd. The presence or absence of high molecular weight components with a molecular weight of 50,000 or more can be confirmed by gel permeation chromatography (GPC). The molecular weight of the high molecular weight components can be between 100,000 and 1,000,000.

[0075] The Mn of urethane (meth)acrylate (C) can be above 4000 and below 20000, above 5000 and below 18000, or above 6000 and below 15000.

[0076] Organotin compounds or amine compounds are used as catalysts when synthesizing the urethane (meth)acrylates involved in this embodiment. Examples of organotin compounds include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate, bis(2-ethylhexyl mercaptoacetate) dibutyltin, bis(isooctyl mercaptoacetate) dibutyltin, and dibutyltin oxide. From the viewpoint of availability or catalyst performance, dibutyltin dilaurate or dibutyltin diacetate is preferred as the catalyst.

[0077] From the viewpoint of adjusting the Young's modulus of the primary resin layer, based on a total of 100 parts by mass of the resin composition, the content of urethane (meth)acrylate (A) is preferably 10 parts by mass or more and 90 parts by mass or less, more preferably 15 parts by mass or more and 85 parts by mass or less, and even more preferably 20 parts by mass or more and 80 parts by mass or less.

[0078] Based on 100 parts by mass of the total amount of the resin composition, the content of urethane (meth)acrylate (B) is preferably 0 parts by mass or more than 50 parts by mass, more preferably 5 parts by mass or more than 45 parts by mass, and even more preferably 10 parts by mass or more than 40 parts by mass.

[0079] Based on 100 parts by mass of the total amount of the resin composition, the content of urethane (meth)acrylate (C) is preferably 0 parts by mass or more than 50 parts by mass, more preferably 5 parts by mass or more than 45 parts by mass, and even more preferably 10 parts by mass or more than 40 parts by mass.

[0080] Based on the total amount of the resin composition, the total content of urethane (meth)acrylate (A), urethane (meth)acrylate (B) and urethane (meth)acrylate (C) can be more than 50 parts by weight and less than 90 parts by weight.

[0081] Photopolymerizable compounds may further include photopolymerizable compounds without urethane bonds (hereinafter referred to as "monomers"). Examples of monomers include (meth)acrylates, N-vinyl compounds, and (meth)acrylamide compounds. Monomers may be monofunctional monomers having one photopolymerizable vinyl unsaturated group or polyfunctional monomers having two or more vinyl unsaturated groups. Monomers may also be used in combination of two or more.

[0082] Examples of monofunctional (meth)acrylates include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, isopentyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, phenoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, and cyclic trimethylolpropane condensate. Formaldehyde acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, dicyclopentyl (meth)acrylate, nonylphenol polyethylene glycol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, isobornyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, m-phenoxybenzyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, and ω-carboxy-polycaprolactone (meth)acrylate.

[0083] Examples of multifunctional (meth)acrylates include: ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, tripropylene glycol dimethacrylate, triethylene glycol dimethacrylate, cyclohexanediethanol dimethacrylate, dipropylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate with hydroxypentanoic acid, 1,3-butanediol dimethacrylate, and 1,4-butanediol dimethacrylate. Ester, diethylene glycol 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-eicosenediol di(meth)acrylate, isopentyl glycol di(meth)acrylate, 3-ethyl-1,8-octanediol di(meth)acrylate, tricyclodecyl 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, PO adduct di(meth)acrylate of bisphenol F, etc., difunctional monomers; trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, trimethylolpropane polypropoxytri(meth)acrylate, trimethylolpropane...] Monomers with three or more functions, such as propane polyethoxy polypropoxy tri(meth)acrylate, tri[(meth)acryloyloxyethyl]isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol polyethoxy tetra(meth)acrylate, pentaerythritol polypropoxy tetra(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 tri[(meth)acryloyloxyethyl]isocyanurate.

[0084] By including (meth)acrylate in the photopolymerizable compound, the Young's modulus of the resin layer can be adjusted. Based on 100 parts by mass of the total amount of the resin composition, the content of (meth)acrylate can be 1 to 50 parts by mass, 3 to 45 parts by mass, or 5 to 40 parts by mass.

[0085] Examples of N-vinyl compounds include, for example, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylmethyloxazolidinone, N-vinylimidazolium, and N-vinyl-N-methylacetamide.

[0086] The curing speed of the resin composition can be further improved by including an N-vinyl compound in the photopolymerizable compound. Based on 100 parts by mass of the total amount of the resin composition, the content of the N-vinyl compound can be 1 to 30 parts by mass, 2 to 20 parts by mass, or 5 to 15 parts by mass.

[0087] Examples of (meth)acrylamide compounds include, for example: dimethyl (meth)acrylamide, diethyl (meth)acrylamide, (meth)acryloylmorpholine, hydroxymethyl (meth)acrylamide, hydroxyethyl (meth)acrylamide, isopropyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, dimethylaminopropylacrylamide / chloromethane salt, diacetone acrylamide, (meth)acryloylpiperidine, (meth)acryloylpyrrolidine, (meth)acrylamide, N-hexyl (meth)acrylamide, N-methyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and N-hydroxymethylpropane (meth)acrylamide.

[0088] By including a (meth)acrylamide compound in the photopolymerizable compound, the curing speed of the resin composition can be further improved. Based on 100 parts by mass of the total amount of the resin composition, the content of the (meth)acrylamide compound can be 1 to 30 parts by mass, 2 to 20 parts by mass, or 3 to 15 parts by mass.

[0089] Photopolymerization initiators can be appropriately selected and used from known free radical photopolymerization initiators. Examples of photopolymerization initiators include: 1-hydroxycyclohexylphenyl ketone (Omnirad 184, manufactured by IGM Resins), 2,2-dimethoxy-2-phenylacetophenone (Omnirad 651, manufactured by IGM Resins), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (Omnirad TPO, manufactured by IGM Resins), ethyl (2,4,6-trimethylbenzoyl)-phenylphosphonate (Omnirad TPO-L, manufactured by IGM Resins), 2-benzyl-2-dimethylamino-4'-morpholinophenylbutanone (Omnirad 369, manufactured by IGM Resins), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholino-4-yl-phenyl)-butane-1-one (Omnirad 379, manufactured by IGM Resins). The following are listed: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, manufactured by IGM Resins) and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one (Omnirad 907, manufactured by IGM Resins).

[0090] Two or more photopolymerization initiators can be used in combination. From the perspective of excellent rapid curing properties of the resin composition, the photopolymerization initiator preferably contains 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0091] Based on the total amount of the resin composition, the content of the photopolymerization initiator is preferably 0.2 parts by mass or more and 5 parts by mass or less, more preferably 0.3 parts by mass or more and 4 parts by mass or less, and even more preferably 0.4 parts by mass or more and 3 parts by mass or less.

[0092] The resin composition involved in this embodiment may further contain photoacid generators, silane coupling agents, leveling agents, defoamers, antioxidants, ultraviolet absorbers, etc.

[0093] As a photoacid generator, it is possible to use a substance with A + B -Sulfonium salts with a specific structure. Examples of sulfonium salts that can be used as photoacid generators include: CPI-100P, 101A, 110P, 200K, 210S, 310B, 410S (manufactured by San-Apro Corporation), Omnicat 270, 290 (manufactured by IGM Resins); and iodomonium salts such as CPI-IK-1 (manufactured by San-Apro Corporation), Omnicat 250 (manufactured by IGM Resins), WPI-113, 116, 124, 169, 170 (manufactured by FUJIFILM Wako Pure Chemical Corporation).

[0094] Examples of silane coupling agents include: tetramethyl silicate, tetraethyl silicate, mercaptopropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, dimethoxydimethylsilane, diethoxydimethylsilane, trimethoxymethylsilane, triethoxymethylsilane, trimethoxyphenylsilane, triethoxyphenylsilane, 3-(meth)acryloyloxypropyltrimethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, γ-epoxypropoxypropylmethyldiethoxysilane, and γ-methylpropene. Acyloxypropyltrimethoxysilane, 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-trimethoxysilylpropylbenzothiazolyltetrasulfide.

[0095] From the viewpoint of coatability, the viscosity of the resin composition according to this embodiment at 25°C is preferably 0.5 Pa·s or more and 20 Pa·s or less, more preferably 0.8 Pa·s or more and 18 Pa·s or less, and even more preferably 1.0 Pa·s or more and 15 Pa·s or less. The viscosity of the resin composition at 25°C can be measured using a Type B viscometer (a "Digital Viscometer DV-II" manufactured by Brookfield Corporation) under the conditions of spindle No. 18 and rotation speed of 10 rpm.

[0096] The resin composition involved in this embodiment can have both low Young's modulus and high tensile strength, and will not produce defects in the primary resin layer, thus forming a resin layer suitable for the primary coating of optical fibers.

[0097] (optical fiber)

[0098] Figure 1 This is a schematic cross-sectional view showing an example of an optical fiber according to this embodiment. The optical fiber 10 includes: a glass fiber 13 containing a core 11 and a cladding 12, and a coating resin layer 16 disposed on the outer periphery of the glass fiber 13 and containing a primary resin layer 14 and a secondary resin layer 15.

[0099] The cladding 12 surrounds the core 11. The core 11 and the cladding 12 mainly contain glass such as quartz glass. For example, the core 11 can be made of germanium-added quartz glass or pure quartz glass, and the cladding 12 can be made of pure quartz glass or fluorine-added quartz glass.

[0100] exist Figure 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 layer of the primary resin layer 14 and the secondary resin layer 15 can be approximately 5 μm to 50 μm.

[0101] When the outer diameter of the glass fiber 13 is approximately 125 μm and the thickness of the coated resin layer 16 is between 60 μm and 70 μm, the thickness of each layer of the primary resin layer 14 and the secondary resin layer 15 can be approximately 10 μm to 50 μm. For example, the thickness of the primary resin layer 14 can be 35 μm, and the thickness of the secondary resin layer 15 can be 25 μm. The outer diameter of the optical fiber 10 can be approximately 245 μm to 265 μm.

[0102] When the outer diameter of the glass fiber 13 is approximately 125 μm and the thickness of the coated resin layer 16 is between 20 μm and 48 μm, the thickness of each layer of the primary resin layer 14 and the secondary resin layer 15 can be approximately 8 μm to 38 μm. For example, the thickness of the primary resin layer 14 can be 25 μm, and the thickness of the secondary resin layer 15 can be 10 μm. The outer diameter of the optical fiber 10 can be approximately 165 μm to 221 μm.

[0103] When the outer diameter of the glass fiber 13 is approximately 100 μm and the thickness of the coated resin layer 16 is between 22 μm and 37 μm, the thickness of each layer of the primary resin layer 14 and the secondary resin layer 15 can be approximately 5 μm to 32 μm. For example, the thickness of the primary resin layer 14 can be 25 μm, and the thickness of the secondary resin layer 15 can be 10 μm. The outer diameter of the optical fiber 10 can be approximately 144 μm to 174 μm.

[0104] By applying the resin composition involved in this embodiment to the primary resin layer, optical fibers with excellent micro-bending resistance and low-temperature properties can be produced.

[0105] The optical fiber manufacturing method according to this embodiment includes: a coating step of coating the above-mentioned resin composition onto the outer periphery of a glass fiber containing a core and a cladding; and a curing step of curing the resin composition by irradiation with ultraviolet light after the coating step.

[0106] From the perspective of improving the micro-bending resistance of optical fibers, the Young's modulus of the primary resin layer is preferably 0.8 MPa or less, more preferably 0.7 MPa or less, and even more preferably 0.5 MPa or less at 23℃±2℃. When the Young's modulus of the primary resin layer exceeds 0.8 MPa, external forces are easily transmitted to the glass fiber, and the increase in transmission loss due to micro-bending can sometimes be greater.

[0107] The Young's modulus of the primary resin layer can be determined using the Pullout Modulus (POM) method at 23°C. Two chucks are used to fix the optical fiber at two points. The portion of the resin coating (primary and secondary resin layers) between the two chucks is removed. Then, one chuck is fixed, and the other chuck is slowly moved in the opposite direction. Let L be the length of the portion of the optical fiber sandwiched between the moving chucks, Z be the chuck movement, Dp be the outer diameter of the primary resin layer, Df be the outer diameter of the glass fiber, n be the Poisson's ratio of the primary resin layer, and W be the load during chuck movement. In this case, the Young's modulus of the primary resin layer can be calculated using the following formula.

[0108] Young's modulus (MPa) = ((1+n)W / πLZ) × ln(Dp / Df)

[0109] The secondary resin layer 15 can be formed, for example, by curing a resin composition containing a photopolymerizable compound comprising urethane (meth)acrylate, a photopolymerization initiator, etc. The resin composition forming the secondary resin layer has a different composition from the resin composition used for the primary coating. The resin composition used for the secondary coating can be prepared using existing known techniques.

[0110] From the viewpoint of improving the micro-bending resistance of optical fibers, the Young's modulus of the secondary resin layer is preferably 800 MPa or more, more preferably 1000 MPa or more, and even more preferably 1200 MPa or more at 23℃±2℃. There is no particular upper limit to the Young's modulus of the secondary resin layer, but from the viewpoint of imparting appropriate toughness to the secondary resin layer, it can be 3000 MPa or less, 2500 MPa or less, or 2000 MPa or less at 23℃±2℃.

[0111] The Young's modulus of the secondary resin layer can be determined by the following method. First, the optical fiber is immersed in a mixed solvent of acetone and ethanol, and only the coated resin layer is pulled out in a cylindrical shape. At this point, the primary and secondary resin layers become a single unit. However, since the Young's modulus of the primary resin layer is more than 1 / 1000 and less than 1 / 10000 of that of the secondary resin layer, the Young's modulus of the primary resin layer can be ignored. Next, the solvent is removed from the coated resin layer by vacuum drying, and then a tensile test is performed at 23°C (tensile speed of 1 mm / min). The Young's modulus can be determined using the secant method with a strain of 2.5%.

[0112] In the optical fiber manufacturing method according to this embodiment, by using the resin composition according to this embodiment as the primary coating resin composition, it is possible to manufacture optical fibers with excellent microbending resistance and low temperature characteristics.

[0113] (Fiber optic ribbon)

[0114] The optical fibers described in this embodiment can be used to fabricate an optical fiber ribbon. The optical fiber ribbon consists of multiple optical fibers arranged side-by-side and coated with resin.

[0115] Figure 2 This is a schematic cross-sectional view illustrating an embodiment of an optical fiber ribbon. The optical fiber ribbon 100 has a plurality of optical fibers 10 and a connecting resin layer 40 that is integrally coated with ribbon resin and connects the optical fibers 10. Figure 2 The example shown has 4 optical fibers 10, but there is no particular limitation on the number of fibers.

[0116] Optical fibers 10 can be integrated in a contact and side-by-side configuration, or a portion or all of the optical fibers 10 can be integrated in a side-by-side configuration with a certain interval between them. The center-to-center distance F between adjacent optical fibers 10 can be between 220 μm and 280 μm. When the center-to-center distance is set to between 220 μm and 280 μm, it is easy to place the optical fibers in the existing V-groove, thereby obtaining an optical fiber ribbon with excellent overall splicing performance. The thickness T of the optical fiber ribbon 100 depends on the outer diameter of the optical fiber 10 and can be between 164 μm and 285 μm.

[0117] Figure 3 This is a schematic cross-sectional view showing an example of an optical fiber ribbon obtained by integrating optical fibers in a parallel configuration with the fibers spaced apart at certain intervals. Figure 3 In the fiber optic ribbon 100A shown, 12 fibers are connected by ribbon resin, with each pair of fibers 10 separated by a certain interval. The ribbon resin forms a connecting resin layer 40.

[0118] As the tape resin, resin materials commonly known as tape materials can be used. From the viewpoint of the fiber optic cable's resistance to damage and ease of splitting, the tape resin can contain thermosetting resins such as silicone resin, epoxy resin, and urethane resin; or UV-curable resins such as epoxy acrylate, urethane acrylate, and polyester acrylate.

[0119] When the optical fibers 10 are spaced apart and arranged side by side, that is, when adjacent optical fibers 10 are joined without contact via a ribbon resin, the thickness of the joint at the center of each optical fiber 10 can be between 150 μm and 220 μm. Since the optical fiber ribbon is prone to deformation when housed in the cable, the optical fiber ribbon may have a recess at the joint. The recess may also be formed as a narrowing triangle on one side of the joint.

[0120] The optical fiber strip involved in this embodiment may have connecting and non-connecting portions intermittently in both the length and width directions. Figure 4 This is a plan view showing the appearance of an optical fiber ribbon according to one embodiment. The optical fiber ribbon 100B includes: multiple optical fibers, multiple connecting portions 20, and non-connecting portions (segmented portions) 21. The non-connecting portions 21 are formed intermittently along the length direction of the optical fiber ribbon. The optical fiber ribbon 100B is an intermittently connected type optical fiber ribbon in which connecting portions 20 and non-connecting portions 21 are intermittently provided in the length direction for every two optical fibers 10A. A "connecting portion" refers to the part where adjacent optical fibers are integrated via a connecting resin layer, and a "non-connecting portion" refers to the part where adjacent optical fibers are not integrated via a connecting resin layer, but rather a gap exists between the optical fibers.

[0121] In the optical fiber ribbon with the above configuration, since a non-connecting portion 21 is intermittently provided in the connecting portion 20 of every two cores, the optical fiber ribbon is prone to deformation. Therefore, when installing the optical fiber ribbon in an optical fiber cable, it can be easily rolled up for installation, thus obtaining an optical fiber ribbon suitable for high-density installation. Furthermore, since the connecting portion 20 can be easily torn starting from the non-connecting portion 21, it is easy to separate individual optical fibers 10 within the optical fiber ribbon.

[0122] The optical fiber ribbon involved in this embodiment has excellent micro-bending resistance and low-temperature characteristics by using the above-mentioned optical fiber, and can be filled into the optical fiber cable at a high density.

[0123] (Fiber optic cable)

[0124] The optical fiber cable according to this embodiment is formed by housing the aforementioned optical fiber ribbon within the cable. For example, a slot-type optical fiber cable having multiple slots can be cited as an example. The aforementioned optical fiber ribbon can be installed in the slots such that the installation density in each slot is approximately 25% to 65%. Installation density refers to the ratio of the cross-sectional area of ​​the optical fiber ribbon installed in the slot to the cross-sectional area of ​​the slot. The optical fiber cable according to this embodiment can also be formed by housing multiple optical fibers within the cable without coating them with a ribbon resin.

[0125] Reference Figure 5 and 6 An example of the optical fiber cable involved in this embodiment will be described. Figure 5 and 6 It can accommodate discontinuously connected fiber ribbons, but it can also accommodate multiple fibers that are not coated with resin.

[0126] Figure 5 This is a schematic cross-sectional view of a slotless optical fiber cable 60 using the aforementioned discontinuously connected optical fiber ribbons 100B. The optical fiber cable 60 has a cylindrical tube 61 and multiple optical fiber ribbons 100B. The multiple optical fiber ribbons 100B can be bundled together using spacers 62 such as aromatic polyamide fibers. Furthermore, the multiple optical fiber ribbons 100B can each have their own distinct markings. The optical fiber cable 60 is a structure formed by twisting the bundled optical fiber ribbons 100B together, extruding resin around them to form the tube 61, and covering it with a jacket 64 along with a tension member 63. Where waterproofing is required, absorbent yarn can be inserted into the inside of the tube 61. The tube 61 can be formed, for example, using resins such as polybutylene terephthalate or high-density polyethylene. Tear cords 65 can be provided on the outside of the tube 61.

[0127] Figure 6 This is a schematic cross-sectional view of a slotted fiber optic cable 70 using the aforementioned discontinuously connected fiber optic ribbon 100B. The fiber optic cable 70 includes a slotted rod 72 with multiple slots 71 and multiple fiber optic ribbons 100B. The fiber optic cable 70 is a structure in which multiple slots 71 are radially arranged on the slotted rod 72, which has a tension member 73 at its center. The multiple slots 71 can be arranged in a spiral or SZ-shaped twisted configuration along the length of the fiber optic cable 70. Each slot 71 accommodates multiple fiber optic ribbons 100B that have shifted from a parallel arrangement to a denser arrangement. The fiber optic ribbons 100B can also be bundled together using an identification binding material. A compression tape 74 is wound around the slotted rod 72, and an outer sheath 75 is formed around the compression tape 74.

[0128] The fiber optic cable with the optical fiber or optical fiber ribbon involved in this embodiment has excellent micro-bending resistance and low temperature characteristics.

[0129] Example

[0130] The following describes the evaluation test results using the embodiments and comparative examples involved in this disclosure, and provides a more detailed explanation of this disclosure. It should be noted that the present invention is not limited to these embodiments.

[0131] [Synthesis of carbamate acrylate (A)]

[0132] (A-1)

[0133] Polypropylene glycol with a Mn of 18000 was reacted with 2-acryloyloxyethyl isocyanate (trade name "Karenz AOI" manufactured by Showa Denko Co., Ltd.) at 60°C for 1 hour with a molar ratio of NCO to OH (NCO / OH) of 1.0 to obtain urethane acrylate (A-1) with a Mn of 25100. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total amount.

[0134] (A-2)

[0135] Polypropylene glycol with a Mn of 18000 was reacted with Karenz AOI at 60°C for 1 hour with an NCO / OH ratio of 0.85 to obtain urethane acrylate (A-2) with a Mn of 25000. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0136] Polypropylene glycol with a Mn of 18000 was reacted with Karenz AOI at 60°C for 1 hour with an NCO / OH ratio of 0.5 to obtain urethane acrylate (A-3) with a Mn of 24900. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0137] (A-4)

[0138] Polypropylene glycol (Mn 18000), Karenz AOI, and 3-(triethoxysilyl)propyl isocyanate were reacted at 60°C for 1 hour with a molar ratio of NCO of Karenz AOI to OH of polypropylene glycol (NCO / OH) of 0.85 and a molar ratio of NCO of 3-(triethoxysilyl)propyl isocyanate to OH of polypropylene polyol (NCO / OH) of 0.15, thereby obtaining urethane acrylate (A-4) with Mn 25100. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0139] (A-5)

[0140] Polypropylene glycol with a Mn of 12000 was reacted with Karenz AOI at 60°C for 1 hour with an NCO / OH ratio of 1.0 to obtain urethane acrylate (A-5) with a Mn of 18300. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0141] (A-6)

[0142] Polypropylene triol with a Mn of 10000 was reacted with Karenz AOI at 60°C for 1 hour with an NCO / OH ratio of 0.6 to obtain urethane acrylate (A-6) with a Mn of 15000. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0143] [Synthesis of carbamate acrylate (B)]

[0144] (B-1)

[0145] An NCO-terminated prepolymer was prepared by reacting polypropylene glycol (Mn 18000) with 2,4-toluene diisocyanate (TDI) at 60°C for 1 hour with an NCO / OH ratio of 2.0. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition. Next, HEA was added such that the molar ratio of OH of 2-hydroxyethyl acrylate (HEA) to the NCO of the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (B-1) with an Mn of 36700.

[0146] (B-2)

[0147] An NCO-terminated prepolymer was prepared by reacting polypropylene glycol (Mn 12000) with TDI at 60°C for 1 hour with an NCO / OH ratio of 2.0. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition. Then, HEA was added such that the molar ratio of OH to NCO in the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (B-2) with an Mn of 24500.

[0148] (B-3)

[0149] An NCO-terminated prepolymer was prepared by reacting polypropylene glycol (Mn 3000) with TDI at 60°C for 1 hour with an NCO / OH ratio of 1.5. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition. Then, HEA was added such that the molar ratio of OH to NCO in the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (B-3) with an Mn of 11300.

[0150] [Synthesis of carbamate acrylate (C)]

[0151] (C-1)

[0152] An NCO-terminated prepolymer was prepared by reacting polypropylene oxide monobutyl ether (trade name "UNILUBE MB-370" manufactured by Nippon Oil Co., Ltd.) with TDI at 60°C for 1 hour with an NCO / OH ratio of 2.0. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total amount. Next, HEA was added such that the molar ratio of OH to NCO in the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (C-1) with an Mn of 6200.

[0153] (C-2)

[0154] An NCO-terminated prepolymer was prepared by reacting polypropylene oxide monobutyl ether (trade name "NewpolLB3000" manufactured by Sanyo Chemical Co., Ltd.) with TDI at 60°C for 1 hour with an NCO / OH ratio of 2.0. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total amount. Then, HEA was added such that the molar ratio of OH to NCO in the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (C-2) with an Mn of 8900.

[0155] (C-3)

[0156] An NCO-terminated prepolymer was prepared by reacting polypropylene oxide monobutyl ether (trade name "AcrobuteMB-90" manufactured by Nippon Oil Co., Ltd.) with TDI at 60°C for 1 hour with an NCO / OH ratio of 2.0. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total amount. Next, HEA was added such that the molar ratio of OH to NCO in the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (C-3) with an Mn of 10000.

[0157] (C-4)

[0158] Acrobute MB-90 and Karenz AOI were reacted at 60°C for 1 hour with an NCO / OH molar ratio of 1.0 to obtain a urethane acrylate (C-4) with a Mn of 8500. As a catalyst, 200 ppm of dibutyltin dilaurate was added relative to the final total addition.

[0159] [Synthesis of carbamate acrylate (Y)]

[0160] (Y-1)

[0161] An NCO-terminated prepolymer was prepared by reacting polypropylene glycol (Mn 3000) with TDI at 60°C for 1 hour with an NCO / OH ratio of 1.5. 200 ppm of dibutyltin dilaurate was added relative to the final total addition. Next, methanol was added to achieve a molar ratio of OH to NCO in the NCO-terminated prepolymer of 0.4, and HEA was added to achieve a molar ratio of OH to NCO in the NCO-terminated prepolymer of 0.65. The reaction was then carried out at 60°C for 1 hour to obtain a urethane acrylate (Y-1) with an Mn of 11200.

[0162] The Mn values ​​for polypropylene polyols and polyoxyalkylene monoalkyl ethers are derived from hydroxyl values ​​and are listed in the respective product catalogs. The Mn values ​​for urethane acrylates were determined using a Waters ACQUITY APC RI system under the following conditions: sample concentration: 0.2% THF solution; injection volume: 20 μL; sample temperature: 15°C; mobile phase: THF; organic solvent; XT column: particle size 2.5 μm; pore size... Column inner diameter 4.6 × column length 150 mm + particle size 2.5 μm, pore size Column inner diameter 4.6 × column length 150 mm + particle size 1.7 μm, pore size Column inner diameter 4.6 × column length 150 mm, column temperature: 40℃, flow rate: 0.8 mL / min.

[0163] As monomers, nonylphenol polyethylene glycol acrylate (trade name "ARONIX M-113" manufactured by Toa Synthetic Co., Ltd.), isobornyl acrylate (IBXA), N-vinylcaprolactam (NVCL), acryloylmorpholine (ACMO), bisphenol A epoxy di(meth)acrylate (trade name "Viscoat#540" manufactured by Osaka Organic Chemicals Co., Ltd.), and tripropylene glycol diacrylate (TPGDA) were prepared. As photopolymerization initiators, 2,4,6-trimethylbenzoyl diphenylphosphine oxide (Omnirad TPO) and 1-hydroxycyclohexylphenyl ketone (Omnirad 184) were prepared. As a silane coupling agent, 3-acryloyloxypropyltrimethoxysilane (APTMS) was prepared.

[0164] [Resin composition for primary coating]

[0165] The photopolymerizable compound, photopolymerization initiator, and silane coupling agent were mixed in the proportions (parts by mass) shown in Tables 1, 2, or 3 to prepare the resin compositions for primary coating in each test example. Test Examples 1-13 correspond to the exemplary examples, and Test Examples 14-17 correspond to the comparative examples.

[0166] (Viscosity)

[0167] The viscosity of the resin composition at 25°C was measured using a Type B viscometer (Brookfield Digital Viscometer DV-II) with spindle No. 18 and a rotation speed of 10 rpm.

[0168] [Resin film]

[0169] The resin composition was coated onto a polyethylene terephthalate (PET) film using a spin coater, and then subjected to UV light at 10 mJ / cm² using an electrodeless UV lamp system (D-Bulb, Heraeus). 2 and 100mW / cm 2 The resin film is cured under certain conditions to form a 200 μm thick resin film on the PET film. The resin film is then peeled off from the PET film.

[0170] (Young's modulus)

[0171] The resin film was punched into a dumbbell shape according to JIS K 7127 Type 5 standards. Tensile testing was conducted at 23±2℃ and 50±10% RH using a tensile testing machine at a tensile speed of 1 mm / min and a mark spacing of 25 mm to obtain the stress-strain curve. The Young's modulus of the resin film was determined by dividing the stress calculated using the secant formula based on 2.5% strain by the cross-sectional area of ​​the resin film.

[0172] (Tear strength and elongation at break)

[0173] The resin film was punched into a dumbbell shape according to JIS K 7127 Type 5 standards. It was then subjected to tensile testing using a tensile testing machine at 23±2℃ and 50±10% RH, with a tensile speed of 50 mm / min and a mark spacing of 25 mm, yielding stress-strain curves. The tensile strength of the resin film was calculated by dividing the stress at fracture by the cross-sectional area of ​​the resin film. Furthermore, the elongation at break was calculated by dividing the displacement at fracture by the mark spacing.

[0174] [Resin composition for secondary coating]

[0175] An NCO-terminated prepolymer was prepared by reacting polypropylene glycol (Mn 600) with TDI at an NCO / OH ratio of 2.0. 200 ppm of dibutyltin dilaurate was added relative to the final total addition. Then, HEA was added such that the molar ratio of OH of 2-hydroxyethyl acrylate (HEA) to the NCO of the NCO-terminated prepolymer was 1.05, and the reaction was carried out at 60°C for 1 hour to obtain a urethane acrylate (Z-1) with an Mn of 2200.

[0176] A secondary coating resin composition was obtained by mixing 25 parts by weight of urethane acrylate (Z-1), 36 parts by weight of TPGTA, 37 parts by weight of Viscoat#540, 1 part by weight of Omnirad TPO, and 1 part by weight of Omnirad 184.

[0177] [optical fiber]

[0178] A primary coating resin composition and a secondary coating resin composition were respectively coated onto the outer peripheral surface of a glass fiber 13 with a diameter of 125 μm. Then, the respective resin compositions were cured by irradiation with ultraviolet light to form a coating resin layer 16 having a primary resin layer 14 and a secondary resin layer 15, thereby fabricating an optical fiber 10. An optical fiber with a primary resin layer 14 thickness of 20 μm, a secondary resin layer 15 thickness of 15 μm, and an outer diameter of 195 μm was obtained.

[0179] (Micro bending resistance)

[0180] The optical fiber 10 was wound in a single layer onto a 280 mm diameter spool covered with sandpaper. The transmission loss of light at a wavelength of 1550 nm was measured using an OTDR (Optical Time Domain Reflectometer). Furthermore, the transmission loss difference of light at a wavelength of 1550 nm when the optical fiber 10 was wound in a single layer onto a 280 mm diameter spool without sandpaper was rated as "A"; 0.5 dB / km to 1.0 dB / km was rated as "B"; and more than 1.0 dB / km was rated as "C".

[0181] (low temperature characteristics)

[0182] A layer of optical fiber was wound onto a glass spool with a tension of 50g. The transmission characteristics of the signal light at a wavelength of 1550nm were measured at temperatures of 23℃ and -40℃, and the transmission loss at 23℃ and -40℃ was determined. Cases where the difference between the transmission loss at -40℃ and the transmission loss at 23℃ is less than 0dB are rated "A"; cases where the difference is between 0dB and 0.01dB / km are rated "B"; and cases where the difference exceeds 0.01dB / km are rated "C".

[0183] [Table 1]

[0184] Test case 1 2 3 4 5 6 A-1 70 - - - - - A-2 - 70 - - - - A-3 - - 70 - - - A-4 - - - 70 - - A-5 - - - - 70 - A-6 - - - - - 70 M-113 13 13 13 13 13 13 IBXA 5 5 5 5 5 5 NVCL 5 5 5 5 5 5 ACMO 5 5 5 5 5 5 Omnirad TPO 1 1 1 1 1 1 APTMS 1 1 1 1 1 1 Viscosity [Pa·s] 5.6 5.4 5.2 5.4 2.4 4.8 Young's modulus [MPa] 0.51 0.29 0.12 0.30 0.68 0.31 Fracture strength [MPa] 0.76 0.95 0.38 0.93 1.02 0.58 Elongation at break [%) 190 210 170 220 120 250 Microbending resistance B A A A B A Low temperature characteristics A A B A A B

[0185] [Table 2]

[0186] Test case 7 8 9 10 11 12 13 A-3 40 40 40 - - - - A-5 - - - 30 30 30 30 B-1 30 - - - - - - B-2 - 30 - - - - - B-3 - - 30 - - - - C-1 - - - 40 - - - C-2 - - - - 40 - - C-3 - - - - - 40 - C-4 - - - - - - 40 M-113 13 13 13 13 13 13 13 IBXA 5 5 5 5 5 5 5 NVCL 5 5 5 5 5 5 5 ACMO 5 5 5 5 5 5 5 Omnirad TPO 1 1 1 1 1 1 1 APTMS 1 1 1 1 1 1 1 Viscosity [Pa·s] 13.4 7.4 5.4 1.8 2.0 2.8 2.2 Young's modulus [MPa] 0.23 0.35 0.26 0.48 0.41 0.24 0.21 Fracture strength [MPa] 1.26 1.08 0.42 0.66 0.64 1.22 1.04 Elongation at break [%) 320 250 130 140 140 180 170 Microbending resistance A A A A A A A Low temperature characteristics A A B B B A A

[0187] [Table 3]

[0188] Test case 14 15 16 17 B-3 70 60 70 - Y-1 - - - 70 M-113 13 23 18 13 IBXA 5 5 5 5 NVCL 5 5 - 5 ACMO 5 5 5 5 Omnirad TPO 1 1 1 1 APTMS 1 1 1 1 Viscosity [Pa·s] 4.9 3.1 7.3 5.0 Young's modulus [MPa] 1.03 0.52 0.31 0.18 Fracture strength [MPa] 1.09 0.54 0.25 0.21 Elongation at break [%) 110 90 80 110 Microbending resistance C B A A Low temperature characteristics A C C C

[0189] Explanation of symbols

[0190] 10 optical fibers

[0191] 11 cores

[0192] 12 cladding layers

[0193] 13. Glass fiber

[0194] 14 Primary resin layer

[0195] 15 secondary resin layers

[0196] 16 Coated resin layer

[0197] 20 Connecting parts

[0198] 21 Non-connecting parts

[0199] 40 Connecting resin layer

[0200] 60 and 70 fiber optic cables

[0201] 61. Cylindrical tube

[0202] 62 Spacers

[0203] 63, 73 Tension members

[0204] 64 and 75 coats

[0205] 65 Tear Rope

[0206] 71 Slit Groove

[0207] 72 slotted rod

[0208] 74 Compressed Belt

[0209] 100, 100A, 100B fiber optic ribbons

Claims

1. A resin composition for the primary coating of an optical fiber, comprising: Photopolymerizable compounds comprising urethane (meth)acrylates as reaction products of polypropylene polyols with a number average molecular weight of 8,000 to 20,000, isocyanate-containing (meth)acrylates, and isocyanate-containing silane compounds; and Photopolymerization initiator.

2. A resin composition for the primary coating of an optical fiber, comprising: Photopolymerizable compounds comprising urethane (meth)acrylate A, which is a reaction product of a polypropylene polyol with a number average molecular weight of 8,000 to 20,000 and an isocyanate-containing (meth)acrylate; and Photopolymerization initiator, The photopolymerizable compound further comprises urethane (meth)acrylate B, which is a reaction product of polypropylene polyol, diisocyanate, and hydroxyl-containing (meth)acrylate, having a number average molecular weight of more than 2,000 and less than 20,000.

3. The resin composition according to claim 2, wherein, The number average molecular weight of the polypropylene polyol contained in the urethane (meth) acrylate B is above 6000 and below 20000.

4. A resin composition for the primary coating of an optical fiber, comprising: Photopolymerizable compounds comprising urethane (meth)acrylates containing the reaction product of a polypropylene polyol with a number average molecular weight of 8,000 to 20,000 and an isocyanate-containing (meth)acrylate; and Photopolymerization initiator, The photopolymerizable compound further comprises a reaction product of a polyoxyalkylene monoalkyl ether, a diisocyanate, and a hydroxyl-containing (meth)acrylate; or a urethane (meth)acrylate as a reaction product of a polyoxyalkylene monoalkyl ether and an isocyanate-containing (meth)acrylate.

5. The resin composition according to claim 4, wherein, The number average molecular weight of the polyoxyalkylene monoalkyl ether is between 2,000 and 10,000.

6. An optical fiber, comprising: Glass fiber containing core and cladding, The primary resin layer that contacts and coats the glass fibers, and The secondary resin layer is covered by the primary resin layer. The primary resin layer comprises a cured product of the resin composition according to any one of claims 1 to 5.

7. A method for manufacturing an optical fiber, comprising: A coating process in which the resin composition of any one of claims 1 to 5 is applied to the outer periphery of a glass fiber containing a core and a cladding. as well as A curing process that cures the resin composition by irradiation with ultraviolet light after the coating process.

8. An optical fiber ribbon comprising a plurality of optical fibers as described in claim 6, and the ribbon being coated with resin.

9. An optical fiber cable, wherein the optical fiber ribbon of claim 8 is incorporated herein by means of the cable.

10. An optical fiber cable comprising a plurality of optical fibers as described in claim 6.

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