Composition for forming an optical fiber coating layer, cured layer thereof, optical fiber having a cured layer, and use of the composition for forming an optical fiber coating layer

Abstract

To provide an optical fiber coating layer forming composition small in Young's modulus change after curing due to an urethane oligomer containing alkoxysilyl groups and capable of obtaining proper glass adhesion.SOLUTION: The problem is solved with an optical fiber coating layer forming composition containing a compound containing a structure expressed by the following formula (I):*-NH-CO-N(R1)-R2-SiR3n-(OR4)3-n (I) [in a formula, R1 is a hydrogen atom, an alkyl group, or an aryl group, R2 is a methylene group that may be substituted with a halogen, a C2-10 alkylene group that may be substituted with a halogen and may have a hetero atom between carbon atoms or an atomic group containing a hetero atom, or a phenylene group that may have a substituent; R3 is an alkyl group, and R4 is a C1 to 6 alkyl group. Here, "*" is a coupling hand, n is an integer having a value of 0 or more and 2 or smaller].SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition for forming an optical fiber coating layer, a cured layer thereof, an optical fiber having the cured layer and a method for manufacturing the same, and use of the composition for forming an optical fiber coating layer.

Background Art

[0002] [[ID=,12]]Optical fibers are manufactured by coating a glass fiber obtained by heat-melting and spinning glass with a resin for the purpose of protection and reinforcement. As this resin coating, a structure is known in which a flexible first coating layer (hereinafter also referred to as "first coating layer") is first provided on the surface of the glass fiber, and a highly rigid second coating layer (hereinafter also referred to as "second coating layer") is provided outside thereof. An optical fiber having a structure in which a first coating layer and a second coating layer are provided on one glass fiber is usually referred to as an optical fiber element wire, and the optical fiber element wire may further have a colored ink layer or an up-jacket layer outside the second coating layer. Further, a tape-shaped optical fiber or an optical fiber cable in which a plurality of these resin-coated optical fiber element wires are bundled with a bundling material is also well known. A resin composition (coating material) for forming the first coating layer of an optical fiber element wire is called a primary material, a resin composition for forming the second coating layer is called a secondary material, and a resin composition used as a bundling material for bundling a plurality of optical fiber element wires is called a bundling material. In addition, there are cases where a plurality of tape-shaped optical fibers or optical fiber cables are further bundled with a bundling material, and the bundling material used at this time is also called a bundling material. As these resin coating methods, a method of applying a liquid curable resin composition and curing it by heat or light, particularly ultraviolet light, is widely used. Among these coating materials, in the primary material, it is necessary for the cured product to be flexible in order to prevent the glass fiber from being bent or the like due to local pressure from the outside. Therefore, the first coating layer usually has a Young's modulus of 0.1 to 10 MPa. Japanese Patent Application Laid-Open No. 2012-111674 discloses a radiation-curable resin composition containing a urethane oligomer and a monofunctional acrylic monomer as a resin composition suitable as a primary material for an optical fiber element wire.

SUMMARY OF THE INVENTION

[0003] An object of the present invention is to obtain an appropriate glass adhesion while suppressing a change in Young's modulus after curing of a primary material made of a urethane oligomer containing an alkoxysilyl group. When the change in Young's modulus of the primary material due to the urethane oligomer containing an alkoxysilyl group blended in the primary material is large, it is not preferable because the transmission characteristics of the optical fiber deteriorate.

[0004] Examples of aspects of the present invention include the following (1) to (25). (1) The following formula (I): *-NH-CO-N(R 1 )-R 2 -SiR 3 n -(OR 4 ) 3-n (I) [In the formula, R 1 is a hydrogen atom, an alkyl group, or an aryl group, R 2 is a methylene group which may be substituted with a halogen, an alkylene group of C 2-10 which may be substituted with a halogen and may have a hetero atom or an atomic group containing a hetero atom between carbon atoms, or a phenylene group which may have a substituent, R 3 is an alkyl group, R 4 is an alkyl group of C 1-6 Here, * is a bond, and n represents an integer of 0 or more and 2 or less.] A composition for forming an optical fiber coating layer containing a compound having a structure represented by (2) The composition for forming an optical fiber coating layer according to (1), wherein R 1 in the formula (I) is a hydrogen atom or an alkyl group of C 1-10 . (3) R 2is an alkylene group of C which may have a heteroatom or an atomic group containing a heteroatom between carbon atoms 2-10 The composition for forming an optical fiber coating layer according to (1) or (2), which is the alkylene group of 2-10 . (4) The composition for forming an optical fiber coating layer according to any one of claims 1 to 3, wherein the heteroatom or the atomic group containing a heteroatom is selected from NH, O, and S. (5) R in formula (I) 3 is C 1-10 The composition for forming an optical fiber coating layer according to any one of (1) to (4), which is an alkyl group of 1-10 . (6) R in formula (I) 4 is C 2-6 The composition for forming an optical fiber coating layer according to any one of (1) to (5), which is an alkyl group of 2-6 . (7) The content of the compound containing the structure represented by formula (I) is 0.05 parts by mass or more and less than 4.5 parts by mass per 100 parts by mass of the composition. The composition for forming an optical fiber coating layer according to any one of (1) to (6). (8) The content of the compound containing the structure represented by formula (I) is 0.4 parts by mass or more and less than 3 parts by mass per 100 parts by mass of the composition. The composition for forming an optical fiber coating layer according to (7). (9) The composition for forming an optical fiber coating layer according to any one of (1) to (8), wherein the compound containing the structure represented by formula (I) is a urethane (meth) acrylate oligomer. (10) The composition for forming an optical fiber coating layer according to (9), wherein the urethane (meth) acrylate oligomer contains one (meth) acrylate group. (11) The composition for forming an optical fiber coating layer according to any one of (1) to (10), further comprising a photoinitiator. (12) The composition for forming an optical fiber coating layer according to any one of (1) to (11), further comprising a reactive diluent monomer. (13) A cured layer formed from the composition for forming an optical fiber coating layer according to any one of (1) to (12). (14) An optical fiber having the cured layer according to (13). An optical fiber ribbon or an optical fiber cable containing two or more of the optical fibers described in (15) and (14). (16) The following formula (I): *-NH-CO-N(R 1 )-R 2 -SiR 3 n -(OR 4 ) 3-n (I) [In the formula, R 1 is a hydrogen atom, an alkyl group, or an aryl group, and R 2 is a methylene group which may be substituted with a halogen, an alkylene group of C 2-10 which may be substituted with a halogen and may have a hetero atom or an atomic group containing a hetero atom between carbon atoms, or a phenylene group which may have a substituent, R 3 is an alkyl group, R 4 is an alkyl group of C 1-6 . Here, * is a bond, and n represents an integer of 0 or more and 2 or less] Use for forming an optical fiber coating layer of a composition for forming an optical fiber coating layer containing a compound represented by the formula. (17) Use for forming an optical fiber coating layer according to (16), wherein R 1 in the formula (I) is a hydrogen atom or an alkyl group of C 1-10 . (18) Use for forming an optical fiber coating layer according to (16) or (17), wherein R 2 in the formula (I) is an alkylene group of C 2-10 which may have a hetero atom or an atomic group containing a hetero atom between carbon atoms. (19) Use for forming an optical fiber coating layer according to any one of (16) to (18), wherein the hetero atom or the atomic group containing a hetero atom is selected from NH, O, and S. (20) Use for forming an optical fiber coating layer according to any one of (16) to (19), wherein R 3 in the formula (I) is an alkyl group of C 1-10 . (21) Use for forming an optical fiber coating layer according to any one of (16) to (19), wherein R 4 in the formula (I) is C 2-6Use for forming an optical fiber coating layer according to any one of (16) to (20), which is an alkyl group. Use for forming an optical fiber coating layer according to any one of (16) to (21), wherein the content of the compound containing the structure represented by formula (I) of (22) is 0.05 parts by mass or more and less than 4.5 parts by mass per 100 parts by mass of the composition. Use for forming an optical fiber coating layer according to (22), wherein the content of the compound containing the structure represented by formula (I) of (23) is 0.4 parts by mass or more and less than 3 parts by mass per 100 parts by mass of the composition. Use for forming an optical fiber coating layer according to any one of (16) to (23), wherein the compound containing the structure represented by formula (I) of (24) is a urethane (meth) acrylate oligomer. Use for forming an optical fiber coating layer according to any one of (16) to (24), wherein the urethane (meth) acrylate oligomer contains one (meth) acrylate group. Use for forming an optical fiber coating layer according to any one of (16) to (25), further comprising a photoinitiator. Use for forming an optical fiber coating layer according to any one of (16) to (26), further comprising a reactive diluent monomer. (28) Disposing the optical fiber coating layer forming composition according to any one of (1) to (12) on at least a part of the surface of the glass fiber, and A method for manufacturing an optical fiber, comprising curing the composition to form a coating layer. A method for manufacturing an optical fiber.

Mode for Carrying Out the Invention

[0005] Hereinafter, an embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the range that does not inhibit the effects of the present invention.

[0006] The composition for forming an optical fiber coating layer of the present embodiment has the following formula (I): *-NH-CO-N(R 1 )-R 2 -SiR3 n -(OR 4 ) 3-n (I) A composition for forming an optical fiber coating layer, containing a compound represented by the following formula (hereinafter also referred to as "component (A)").

[0007] In formula (I), R 1 is a hydrogen atom, an alkyl group, or an aryl group. R 1 is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom. The alkyl group is preferably an alkyl group having C 1-10 and more preferably an alkyl group having C 1-6 The aryl group is preferably an aryl group having C 6-10 . In formula (I), R 2 is a methylene group, an alkylene group having 2 to 10 carbon atoms (hereinafter referred to as "C 2-10 ", etc.), or a phenylene group which may have a substituent. Examples of the substituent of phenylene include halogen, hydroxyl group, an alkyl group having C 1-6 , and an alkoxy group having C 1-6 . R 2 is preferably a methylene group or an alkylene group having C 2-10 , and more preferably an alkylene group having C 2-6 The above methylene group and alkylene group may be substituted with halogen, and the above alkylene group may have a hetero atom or an atomic group containing a hetero atom between carbon atoms. Examples of the above hetero atom include an oxygen atom, a sulfur atom, etc., examples of the atomic group containing a hetero atom include NH, etc., and examples of the halogen include fluorine, chlorine, bromine. In formula (I), R 3 is an alkyl group, preferably an alkyl group having C 1-10 , and more preferably an alkyl group having C 1-6 . In formula (I), R 4 is an alkyl group having C 1-6 and is an alkyl group having C2-6 is preferably an alkyl group having C 2-4 and more preferably an alkyl group having Here, * is a bond, and n represents an integer of 0 or more and 2 or less. n is preferably 0 or 1, and more preferably 0.

[0008] Although not limited thereto, specific examples of the structure of formula (I) include the following structures. *-NH-CO-NH-(CH2)3-Si(OMe)3 Formula (IV) *-NH-CO-NH-(CH2)3-Si(OEt)3 Formula (V)

[0009] The "primary coating layer of the optical fiber" is understood to be the coating layer arranged at the position closest to the glass fiber among the coating layers provided on the glass fiber. The primary coating layer may be provided so as to cover at least a part of the glass fiber surface. "For forming the primary coating layer of the optical fiber" is understood to be usable for forming the primary coating layer of the optical fiber or for forming the primary coating layer of the optical fiber. The composition of this embodiment is particularly suitable as a material for forming the primary coating layer of the optical fiber (primary material).

[0010] The "urethane (meth) acrylate oligomer" is understood to be an oligomer containing one or more (meth) acryloyl groups in the molecule and a urethane bond (-NHCOO-) in the repeating unit of the main chain. The urethane (meth) acrylate oligomer can generally be formed by reacting a diol, a diisocyanate, and a hydroxyl group-containing (meth) acrylate to form a urethane bond. The diols, diisocyanates, and hydroxyl group-containing (meth) acrylates that can be used will be described later.

[0011] "Containing the structure" is understood to mean that the urethane (meth) acrylate oligomer contains at least one structure of the above formula (I) in its structure. Preferably, the structure of formula (I) is contained at at least one end of the main chain.

[0012] Component (A) is preferably a urethane (meth) acrylate oligomer. Hereinafter, the urethane (meth) acrylate oligomer as component (A) is also referred to as "urethane oligomer (A)". Urethane oligomer (A) preferably has a structure of formula (I) at at least one end of the main chain, and more preferably has a structure of formula (I) at only one end.

[0013] The diol forming the urethane bond of urethane oligomer (A) is not particularly limited, but aliphatic polyether diols are preferred, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and aliphatic polyether diols obtained by ring-opening copolymerization of two or more ion-polymerizable cyclic compounds.

[0014] Examples of the ion-polymerizable cyclic compounds include cyclic ethers such as ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and glycidyl benzoate.

[0015] Specific examples of the polyether diol obtained by ring-opening copolymerization of two or more of the above ion-polymerizable cyclic compounds include, for example, binary copolymers obtained from combinations such as tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, butene-1-oxide and ethylene oxide; and ternary polymers obtained from combinations of tetrahydrofuran, butene-1-oxide and ethylene oxide, etc.

[0016] Also, polyether diols obtained by ring-opening copolymerization of the above ion-polymerizable cyclic compounds with cyclic imines such as ethyleneimine; cyclic lactonic acids such as β-propiolactone and glycolic acid lactide; or dimethylcyclopolysiloxanes can also be used.

[0017] The above aliphatic polyether diols can also be obtained as commercially available products such as PTMG650, PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical Corporation), PPG400, PPG1000, PPG3000, EXCENOL720, 1020, 2020 (manufactured by AGC Inc.), PEG1000, UNISAFE DC1100, DC1800 (manufactured by NOF Corporation), PPTG2000, PPTG1000, PTG400, PTGL2000 (manufactured by Hodogaya Chemical Co., Ltd.), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B, EO / BO4000, EO / BO2000 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Acclaim2200, 2220, 3201, 3205, 4200, 4220, 8200, 12000 (manufactured by Sumitomo Bayer Urethane Co., Ltd.), etc.

[0018] Among these aliphatic polyether diols, it is preferable to use a ring-opening polymer of one or more ion-polymerizable cyclic compounds having 2 to 4 carbon atoms and having a diol with an average molecular weight of 1000 to 5000 from the viewpoint of achieving both high-speed coatability of the resin liquid and flexibility of the coating material. Examples of such preferable diol compounds include ring-opening polymers of one or more oxides selected from ethylene oxide, propylene oxide, butene-1-oxide, and isobutene oxide, and having an average molecular weight of 1000 to 4000. Particularly preferable is a ring-opening polymer of propylene oxide having an average molecular weight of 1000 to 3000.

[0019] Examples of the diisocyanate that forms the urethane bond of the urethane oligomer (A) include aromatic diisocyanates, alicyclic diisocyanates, aliphatic diisocyanates, and the like. Examples of aromatic diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, bis(2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, tetramethylxylylene diisocyanate, and the like. Examples of alicyclic diisocyanates include isophorone diisocyanate, methylene bis(4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, 2,6-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, and the like. Examples of aliphatic diisocyanates include 1,6-hexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like.

[0020] Among these, aromatic diisocyanates are more preferred from the viewpoint of obtaining a composition having economic efficiency and stable quality, and 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate are particularly preferred. These diisocyanates may be used alone or in combination of two or more.

[0021] As the hydroxyl group-containing (meth)acrylate compound used in the synthesis of the urethane oligomer (A), it is preferable to use a hydroxyl group-containing (meth)acrylate in which the hydroxyl group is bonded to a primary carbon atom (referred to as a primary hydroxyl group-containing (meth)acrylate) and a hydroxyl group-containing (meth)acrylate in which the hydroxyl group is bonded to a secondary carbon atom (referred to as a secondary hydroxyl group-containing (meth)acrylate), and a primary hydroxyl group-containing (meth)acrylate is particularly preferred. A hydroxyl group-containing (meth)acrylate in which the hydroxyl group is bonded to a tertiary carbon atom (referred to as a tertiary hydroxyl group-containing (meth)acrylate) is not preferable because of its poor reactivity with an isocyanate group (hereinafter also referred to as "NCO").

[0022] Examples of the primary hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,6-hexanediol mono (meth)acrylate, pentaerythritol tri (meth)acrylate, dipentaerythritol penta (meth)acrylate, neopentyl glycol mono (meth)acrylate, trimethylolpropane di (meth)acrylate, trimethylolethane di (meth)acrylate, and the like.

[0023] Examples of the secondary hydroxyl group-containing (meth)acrylate include 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, and the like, and also include compounds obtained by an addition reaction of a glycidyl group-containing compound such as an alkyl glycidyl ether, an allyl glycidyl ether, or glycidyl (meth)acrylate with (meth)acrylic acid.

[0024] The content of the urethane oligomer (A) in the composition for forming an optical fiber coating layer of the present invention is preferably 0.05 parts by mass or more and less than 10 parts by mass, more preferably 0.05 parts by mass or more and less than 5 parts by mass, still more preferably 0.05 parts by mass or more and less than 4.5 parts by mass, even more preferably 0.4 parts by mass or more and less than 4.5 parts by mass, and particularly preferably 0.4 parts by mass or more and less than 3 parts by mass or 0.5 parts by mass or more and less than 3 parts by mass per 100 parts by mass of the composition. By the content of the urethane oligomer (A) being within these ranges, it is possible to obtain an appropriate glass adhesion while suppressing the change in Young's modulus after curing of the primary material.

[0025] The synthesis of the urethane oligomer (A) is preferably carried out by reacting a diol component and a diisocyanate component and then reacting a compound containing the structure of the following formula (II) and a hydroxyl group-containing (meth)acrylate. By such a reaction, a urethane oligomer preferably capped at one or both ends with a compound containing the structure of formula (I) is obtained. A urethane oligomer capped at one end with a compound containing the structure of formula (I) is more preferable. By appropriately adjusting the ratio of the compound containing the structure of the following formula (II) and the hydroxyl group-containing (meth)acrylate, a urethane oligomer capped at one end with a compound containing the structure of formula (I) can be obtained.

[0026] NH(R 1 )-R 2 -SiR 3 n -(OR 4 ) 3-n (II)

[0027] R in the above formula (II) 1 , R 2 , R 3 , R 4 and n are the same as those in formula (I), respectively. Examples of the compound containing the structure of the above formula (II) preferably include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, etc., and γ-aminopropyltriethoxysilane is more preferable.

[0028] In the synthesis of the urethane oligomer (A), it is preferable to use a urethanization catalyst selected from copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, dioctyltin dilaurate, triethylamine, 1,4-diazabicyclo[2.2.2]octane, 2,6,7-trimethyl-1,4-diazabicyclo[2.2.2]octane, etc. in an amount of 0.01 to 1% by mass based on the total amount of the reactants. The reaction temperature is usually preferably 5 to 90°C, particularly preferably 10 to 80°C.

[0029] In one embodiment, a urethane (meth)acrylate oligomer other than the component (A) can be blended in the composition for forming the optical fiber coating layer. The urethane (meth)acrylate oligomer other than the component (A) is not particularly limited as long as it is a urethane (meth)acrylate oligomer not containing the structure of the above formula (I), and examples thereof include a urethane (meth)acrylate oligomer having two (meth)acryloyl groups in the molecule, a urethane (meth)acrylate oligomer having one (meth)acryloyl group and one hydroxyl group in the molecule, and a urethane (meth)acrylate oligomer having one (meth)acryloyl group and one silicon-containing group other than the above formula (I) in the molecule. The urethane (meth)acrylate oligomer having two (meth)acryloyl groups in the molecule is, for example, a urethane (meth)acrylate oligomer obtained by reacting a diol, a diisocyanate, and a hydroxyl group-containing (meth)acrylate. Examples of the urethane (meth)acrylate oligomer having one (meth)acryloyl group and one hydroxyl group in the molecule include a urethane (meth)acrylate oligomer having one (meth)acryloyl group derived from a hydroxyl group-containing (meth)acrylate and a hydroxyl group derived from an alcohol. Examples of urethane (meth)acrylate oligomers having one (meth)acryloyl group and one silicon-containing group other than those of formula (I) in the molecule include urethane (meth)acrylate oligomers having one (meth)acryloyl group derived from a hydroxyl group-containing (meth)acrylate and a hydroxyl group derived from a silane coupling agent other than those of formula (I). Examples of silane coupling agents other than those of formula (I) include γ-mercaptopropyltrimethoxysilane.

[0030] In one embodiment, the composition for forming an optical fiber coating layer may contain a urethane oligomer having no (meth)acryloyl group in the molecule. The urethane oligomer having no (meth)acryloyl group in the molecule is, for example, a urethane oligomer obtained by reacting a diol, a diisocyanate, and an alcohol. The alcohol is preferably a lower alcohol having 1 to 8 carbon atoms, such as an aliphatic alcohol such as methanol or n-octanol.

[0031] In one embodiment, the composition for forming an optical fiber coating layer may also contain a compound (component (B)) having one ethylenically unsaturated group other than component (A). Component (B) is typically a monomer having one ethylenically unsaturated group. Examples of component (B) include aliphatic structure-containing (meth)acrylates, alicyclic structure-containing (meth)acrylates, aromatic structure-containing (meth)acrylates, vinyl group-containing lactams, and (meth)acrylamides. Among these, examples of the aliphatic structure-containing (meth)acrylate of component (B) include butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, and isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxyethylene glycol (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and the like. Examples of the alicyclic structure-containing (meth)acrylate of component (B) include isobornyl (meth)acrylate, bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-butylcyclohexyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate. Examples of the aromatic structure-containing (meth)acrylate that is component (B) include benzyl (meth)acrylate. Examples of the vinyl group-containing lactam that is component (B) include N-vinylpyrrolidone and N-vinylcaprolactam. Examples of (meth)acrylamides as component (B) include diacetone (meth)acrylamide, isobutoxymethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, t-octyl (meth)acrylamide, As component (B), in addition to the compounds listed above, acryloylmorpholine, vinylimidazole, vinylpyridine, etc.; examples of the hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl acrylate, etc. Among these component (B)s, aliphatic structure-containing (meth)acrylates such as 2-ethylhexyl (meth)acrylate and vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam are preferred.

[0032] Moreover, as commercially available products of the above component (B), Aronix M-111, M-113, M-114, M-117 (manufactured by Toagosei Co., Ltd.); Kayarad, TC110S, R629, R644 (manufactured by Nippon Kayaku Co., Ltd.); IBXA, Biscoat 3700 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), etc. can be mentioned.

[0033] Component (B) is preferably blended in an amount of 5 to 45% by mass, particularly 10 to 30% by mass, based on 100% by mass of the total amount of the liquid curable resin composition of the present invention. In terms of parts by mass, component (B) is preferably blended in an amount of 5 parts by mass or more and 45 parts by mass or less, particularly 10 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total amount of the composition of the present invention.

[0034] In one embodiment, the composition for forming an optical fiber coating layer may contain a compound (component (C)) containing two or more ethylenically unsaturated groups. (Component (C) is typically a monomer containing two or more ethylenically unsaturated groups. Components (B) and (C) may also be referred to as reactive diluent monomers. Specific examples include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane trioxyethyl ( ... Examples of such compounds include tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, diol di(meth)acrylate of an adduct of bisphenol A with ethylene oxide or propylene oxide, diol di(meth)acrylate of an adduct of hydrogenated bisphenol A with ethylene oxide or propylene oxide, epoxy(meth)acrylate obtained by adding (meth)acrylate to diglycidyl ether of bisphenol A, and triethylene glycol divinyl ether. Examples of commercially available compounds include Iupimer UV. Examples of suitable surfactants include SA1002 and SA2007 (manufactured by Mitsubishi Chemical Corporation); Viscoat 700 (manufactured by Osaka Organic Chemical Industry Co., Ltd.); KAYARAD R-604, DPCA-20, -30, -60, -10, HX-620, D-310, and D-330 (manufactured by Nippon Kayaku Co., Ltd.); and Aronix M-210, M-215, M-315, and M-325 (manufactured by Toagosei Co., Ltd.).

[0035] The content of the compound containing two or more ethylenically unsaturated groups is preferably 2% by mass or less (0 to 2% by mass), more preferably 1.5% by mass or less (0 to 1.5% by mass) based on the total amount of the resin composition, from the viewpoint that it is easy to adjust the Young's modulus of the cured product within a range suitable as the primary material (first coating layer forming material) of the optical fiber. In terms of parts by mass, component (C) is preferably 2 parts by mass or less (0 to 2 parts by mass), more preferably 1.5 parts by mass or less (0 to 1.5 parts by mass) based on 100 parts by mass of the total amount of the composition.

[0036] When the resin composition of the present invention is photocured, a photopolymerization initiator (component (D)) is used, and a photosensitizer can be added as needed. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzil dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenyl Examples of suitable thioxanthone include propan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; IRGACURE 184, 369, 651, 500, 907, CGI 1700, CGI 1750, CGI 1850, CG24-61, DAROCUR 1116, and 1173 (all manufactured by Ciba Specialty Chemicals); LUCIRIN TPO (manufactured by BASF); and Ubecryl P36 (manufactured by UCB). Examples of photosensitizers include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate; Ubecryl P102, 103, 104, and 105 (all manufactured by UCB).

[0037] The photopolymerization initiator (D) is preferably blended in an amount of 0.1 to 10 mass%, particularly 0.3 to 7 mass%, relative to 100 mass% of the total amount of the liquid curable resin composition of the present invention. In terms of parts by mass, the photopolymerization initiator (D) is preferably blended in an amount of 0.1 to 10 mass parts, particularly 0.3 to 7 mass parts, relative to 100 mass parts of the total amount of the composition.

[0038] In one embodiment, a silane coupling agent may be blended into the composition for forming an optical fiber coating layer within a range that does not impair the effects of the invention. The silane coupling agent is not particularly limited, and examples thereof include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane. Other examples of silane coupling agents that can be used include bis-[3-(triethoxysilyl)propyl]tetrasulfide, bis-[3-(triethoxysilyl)propyl]disulfide, γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfide, and γ-trimethoxysilylpropylbenzothiazyltetrasulfide. Commercially available examples include SH6062 and SZ6030 (manufactured by Toray Dow Corning Silicone Co., Ltd.), and KBE903, 603, and 403 (manufactured by Shin-Etsu Chemical Co., Ltd.). Among these silane coupling agents, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane are preferred from the viewpoint of adhesion between the coating and glass. These silane coupling agents may be used alone or in combination of two or more.

[0039] The content of the silane coupling agent is preferably 0.01 to 2 mass%, more preferably 0.1 to 1.5 mass%, and particularly preferably 0.5 to 1.5 mass%, relative to the total amount of the composition for forming an optical fiber coating layer, from the viewpoint of maintaining the adhesive strength between the cured product and the glass fiber. In terms of parts by mass, the content of the silane coupling agent is preferably 0.01 to 2 mass parts, more preferably 0.1 to 1.5 mass parts, and particularly preferably 0.5 to 1.5 mass parts, relative to 100 parts by mass of the total amount of the composition, from the viewpoint of maintaining the adhesive strength between the cured product and the glass fiber.

[0040] In one embodiment, in addition to the above components, various additives such as antioxidants, colorants, ultraviolet absorbers, light stabilizers, thermal polymerization inhibitors, leveling agents, surfactants, storage stabilizers, plasticizers, lubricants, solvents, fillers, antioxidants, wettability improvers, and coating surface improvers may be blended as needed.

[0041] Examples of antioxidants include IRGANOX 245, 1010, 1035, 1076, and 1222 (all manufactured by BASF Japan Ltd.), ANTIGENE P, 3C, Sumilizer GA-80, and GP (manufactured by Sumitomo Chemical Co., Ltd.). Examples of ultraviolet absorbers include TINUVIN P, 234, 320, 326, 327, 328, 329, and 213 (all manufactured by BASF Japan Ltd.), and Seesorb 102, 103, 501, 202, 712, and 704 (manufactured by Shipro Chemical Co., Ltd.). Examples of light stabilizers include TINUVIN 292, 144, and 622LD, Sanol LS-770 and 765 (all manufactured by BASF Japan Ltd.), and TM-061 (manufactured by Sumitomo Chemical Co., Ltd.).

[0042] Furthermore, although the surfactant is not particularly limited, fatty acid ester-type nonionic surfactants are preferred because they effectively suppress the occurrence of defects when the optical fiber strand is immersed in warm water, and nonionic surfactants such as glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxysorbitol fatty acid esters are particularly preferred.

[0043] In one embodiment, the composition for forming an optical fiber coating layer of the present invention can optionally contain other oligomers, polymers, silane compounds such as tetraethoxysilane (silane compounds other than the above-mentioned silane coupling agent), other additives, etc., within a range that does not impair the effects of the present invention.

[0044] Other oligomers and polymers include, for example, polyester (meth)acrylate, epoxy (meth)acrylate, polyamide (meth)acrylate, siloxane polymer containing a (meth)acryloyloxy group, and glycidyl methacrylate.

[0045] The method for producing the composition for forming an optical fiber coating layer is not particularly limited, and can be carried out by melt-blending in a conventionally known reaction vessel equipped with a stirrer.

[0046] The viscosity of the composition for forming an optical fiber coating layer at 25° C. is preferably 0.1 to 10 Pa·s, more preferably 1 to 8 Pa·s, from the viewpoint of handling and application properties.

[0047] The cured layer of the composition for forming an optical fiber coating layer has a low Young's modulus suitable as the primary coating layer of the optical fiber. From the viewpoint that the Young's modulus of the cured product of the composition for forming an optical fiber coating layer can preferably be used as the primary coating layer of the optical fiber as the value after 14 days have passed since the formation of the cured layer, it is preferably 0.1 MPa or more and 1.0 MPa or less (0.1 to 1.0 MPa) at 25°C. When the Young's modulus of the cured layer of the composition for forming an optical fiber coating layer is 0.1 to 1.0 MPa at 25°C, so-called microbending, in which the glass fiber bends when pressure is locally applied to the optical fiber, can be prevented. The Young's modulus of the cured layer of the composition for forming an optical fiber coating layer is more preferably 0.2 MPa or more and 0.9 MPa or less (0.2 to 0.9 MPa), and even more preferably 0.3 MPa or more and 0.85 MPa or less (0.3 to 0.85 MPa).

[0048] The Young's modulus shows a certain change over time after the formation of the cured film. The amount of change in the Young's modulus 14 days after the formation of the cured layer is preferably 0.05 MPa or less, and more preferably 0.04 MPa or less. By having the amount of change in the Young's modulus within this range, an optical fiber with more stable quality (particularly excellent transmission characteristics) can be obtained.

[0049] The glass adhesion is preferably 40 N / m or more and less than 85 N / m as the value after 14 days have passed since the formation of the cured layer, more preferably 50 N / m or more and less than 70 N / m, and particularly preferably 50 N / m or more and less than 65 N / m. By having the glass adhesion within this range, even when pressure is locally applied to the optical fiber, the glass fiber and the cured film are difficult to peel off, and an optical fiber with stable quality can be obtained. In addition, the workability of peeling off and removing the cured film, which is the coating layer, when performing connection work on the optical fiber is improved.

[0050] The glass adhesion shows a certain change over time after the formation of the cured film. The change over 14 days after the formation of the cured layer is preferably 15 N / m or more and less than 60 N / m, more preferably 15 N / m or more and less than 40 N / m, and particularly preferably 20 N / m or more and less than 40 N / m. When the change in glass adhesion is within this range, optical fiber with more stable quality can be manufactured.

[0051] The composition for forming an optical fiber coating layer preferably exhibits a Young's modulus and glass adhesion within the above ranges. Furthermore, it is more preferable from the viewpoint of the stability of the quality of the optical fiber that the change in Young's modulus over time be within the above range, thereby suppressing the change in Young's modulus after curing and providing an appropriate glass adhesion. It is also more preferable that the change in glass adhesion over time be within the above range, and it is even more preferable that both the change in Young's modulus over time and the change in glass adhesion over time be within the above ranges.

[0052] An optical fiber including a cured layer of a composition for forming an optical fiber coating has a cured layer of the composition for forming an optical fiber coating formed on the surface of a glass fiber as a primary coating layer. The optical fiber preferably includes a secondary coating layer that is in contact with the outside of the primary coating layer and has a Young's modulus of 1,000 MPa or more, preferably 1,000 to 2,000 MPa. A glass fiber having a primary coating layer and a second coating layer formed in this order on its surface can be used as an optical fiber.

[0053] A method for manufacturing an optical fiber includes disposing an optical fiber coating layer-forming composition on at least a portion of the surface of a glass fiber, and curing the optical fiber coating layer-forming composition, wherein the optical fiber coating layer-forming composition contains the above-mentioned optical fiber coating layer-forming composition.

[0054] The method for disposing the composition for forming an optical fiber coating layer on at least a portion of the surface of the glass fiber is not limited, and can be carried out by a conventionally known method, such as applying a radiation-polymerizable composition to the surface of the glass fiber or immersing the glass fiber in the composition for forming an optical fiber coating layer.

[0055] The method for curing the composition for forming an optical fiber coating layer by irradiation with radiation is not particularly limited, and the radiation-polymerizable composition is irradiated with one or more rays selected from infrared rays, visible light, ultraviolet rays, X-rays, electron beams, α rays, β rays, γ rays, and the like.

[0056] Optical fibers are generally manufactured by applying a primary material and a secondary material to a molten quartz base material, which is then thermally melted and drawn, and then curing the material with radiation to form a primary coating layer and a secondary coating layer. An assembly such as an optical fiber ribbon or an optical fiber cable is an assembly containing two or more optical fibers each containing a cured layer of the above-mentioned composition for forming an optical fiber coating layer, and can be a tape-shaped optical fiber or an optical fiber cable in which the optical fibers are bound with a bundling material. [Example]

[0057] The present invention will be explained in more detail below by showing examples, but the interpretation of the present invention is not limited to these examples.

[0058] [Synthesis of urethane acrylate] (Synthesis Example 1) Synthesis Example 1 of Urethane Acrylate (A) Into a reaction vessel equipped with a stirrer, 65.2 g of polypropylene glycol with a number average molecular weight of 2,000, 7.57 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and these were heated with stirring until the liquid temperature reached 40 °C. Subsequently, after adding 0.0200 g of dibutyltin dilaurate, the liquid temperature was raised to 60 °C over 10 minutes with stirring. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.17 mass% (ratio to the charged amount) or less, 0.315 g of γ-aminopropyltriethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70 °C for 60 minutes. After the residual isocyanate group concentration became 0.313 mass% (ratio to the charged amount) or less, 0.178 g of methanol was added, and the reaction was carried out at a liquid temperature of 70 °C for 60 minutes. The reaction was terminated when the residual isocyanate group concentration became 0.0500 mass% or less. The obtained urethane oligomer is a mixture of three types of urethane oligomers described in Example 1 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-NH-(CH2)3-Si(OEt)3", and "HT-(PPG2000-T)3-OMe". In the structure of the urethane oligomer shown in Table 2, "H" represents a hydroxyethyl acrylate residue, "T" represents a tolylene diisocyanate residue, "PPG2000" represents a polypropylene glycol residue with a molecular weight of 2,000, "Me" represents a methyl group, and "Et" represents an ethyl group respectively.

[0059] (Synthesis Example 2) Synthesis Example 2 of Urethane Acrylate (A) Into a reaction vessel equipped with a stirrer, 65.4 g of polypropylene glycol with a number average molecular weight of 2000, 7.60 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and these were heated with stirring until the liquid temperature reached 40 °C. Subsequently, 0.0200 g of dibutyltin dilaurate was added, and then the liquid temperature was raised to 60 °C over 10 minutes with stirring. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.25 mass% (ratio to the charged amount) or less, 0.0315 g of γ-aminopropyltriethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70 °C for 60 minutes. After the residual isocyanate group concentration became 0.386 mass% (ratio to the charged amount) or less, 0.220 g of methanol was added, and the reaction was carried out at a liquid temperature of 70 °C for 60 minutes. The reaction was terminated when the residual isocyanate group concentration became 0.0500 mass% or less. The obtained urethane oligomer is a mixture of three types of urethane oligomers described in Example 5 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-NH-(CH2)3-Si(OEt)3", and "HT-(PPG2000-T)3-OMe".

[0060] (Synthesis Example 3) Synthesis of Urethane Acrylate (A) 3 Into a reaction vessel equipped with a stirrer, 65.3 g of polypropylene glycol with a number average molecular weight of 2,000, 7.58 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and these were heated with stirring until the liquid temperature reached 40°C. Subsequently, after adding 0.0200 g of dibutyltin dilaurate, the liquid temperature was raised to 60°C over 10 minutes with stirring. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.25% by mass (ratio to the charged amount) or less, 0.256 g of γ-aminopropyltrimethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70°C for 60 minutes. After the residual isocyanate group concentration became 0.311% by mass (ratio to the charged amount) or less, 0.178 g of methanol was added, and the reaction was carried out at a liquid temperature of 70°C for 60 minutes. The reaction was terminated when the residual isocyanate group concentration became 0.0500% by mass or less. The obtained urethane oligomer is a mixture of three types of urethane oligomers described in Example 8 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-NH-(CH2)3-Si(OMe)3", and "HT-(PPG2000-T)3-OMe".

[0061] (Comparative Synthesis Example 4) Synthesis Example 1 of urethane acrylate not corresponding to component (A) Into a reaction vessel equipped with a stirrer, 65.3 g of polypropylene glycol with a number average molecular weight of 2,000, 7.58 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and these were heated while stirring until the liquid temperature reached 40°C. Subsequently, after adding 0.0200 g of dibutyltin dilaurate, the liquid temperature was raised to 60°C over 10 minutes while stirring. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.25% by mass (ratio to the charged amount) or less, 0.280 g of γ-mercaptopropyltrimethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70°C for 90 minutes. After the residual isocyanate group concentration became 0.312% by mass (ratio to the charged amount) or less, 0.178 g of methanol was added, and the reaction was carried out at a liquid temperature of 70°C for 60 minutes. The reaction was terminated when the residual isocyanate group concentration became 0.0500% by mass or less. The obtained urethane oligomer is a mixture of three urethane oligomers described in Comparative Example 2 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-S-(CH2)3-Si(OMe)3", and "HT-(PPG2000-T)3-OMe".

[0062] (Comparative Synthesis Example 5) Synthesis Example 2 of urethane acrylate not corresponding to Component (A) Into a reaction vessel equipped with a stirrer, 65.4 g of polypropylene glycol with a number average molecular weight of 2,000, 7.59 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and these were heated with stirring until the liquid temperature reached 40°C. Subsequently, after adding 0.0200 g of dibutyltin dilaurate, the liquid temperature was raised to 60°C over 10 minutes with stirring. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.25% by mass (ratio to the charged amount) or less, 0.140 g of γ-mercaptopropyltrimethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70°C for 90 minutes. After the residual isocyanate group concentration became 0.353% by mass (ratio to the charged amount) or less, 0.201 g of methanol was added, and the reaction was carried out at a liquid temperature of 70°C for 60 minutes. The reaction was terminated when the residual isocyanate group concentration became 0.0500% by mass or less. The obtained urethane oligomer is a mixture of three types of urethane oligomers described in Comparative Example 3 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-S-(CH2)3-Si(OMe)3", and "HT-(PPG2000-T)3-OMe".

[0063] (Comparative Synthesis Example 6) Synthesis Example 3 of urethane acrylate not corresponding to Component (A) Into a reaction vessel equipped with a stirrer, 65.4 g of polypropylene glycol with a number average molecular weight of 2,000, 7.60 g of 2,4-tolylene diisocyanate, and 0.0180 g of 2,6-di-t-butyl-p-cresol were charged respectively, and while stirring these, they were heated until the liquid temperature reached 40 °C. Subsequently, after adding 0.0200 g of dibutyltin dilaurate, while stirring, the liquid temperature was raised to 60 °C over 10 minutes. Then, it was stirred for 60 minutes. After the residual isocyanate group concentration became 1.25 mass% (ratio to the charged amount) or less, 0.0280 g of γ-mercaptopropyltrimethoxysilane and 1.72 g of 2-hydroxyethyl acrylate were added, and the reaction was carried out at a liquid temperature of 70 °C for 90 minutes. After the residual isocyanate group concentration became 0.386 mass% (ratio to the charged amount) or less, 0.220 g of methanol was added, and the reaction was carried out at a liquid temperature of 70 °C for 60 minutes. When the residual isocyanate group concentration became 0.0500 mass% or less, the reaction was terminated. The obtained urethane oligomer is a mixture of three types of urethane oligomers described in Comparative Example 4 of Table 2, namely, "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-S-(CH2)3-Si(OMe)3", and "HT-(PPG2000-T)3-OMe".

[0064] The recipe change points when synthesizing a urethane oligomer mixture with a content of γ-aminopropyltriethoxysilane-capped urethane acrylate oligomer different from that in Synthesis Examples 1 to 3 above are shown in Table 1. The synthesis examples shown in Table 1 correspond in order from the top to the urethane oligomer mixtures of "HT-(PPG2000-T)3-H", "HT-(PPG2000-T)3-S-(CH2)3-Si(OMe)3", and "HT-(PPG2000-T)3-OMe" used in Examples 1 to 7 and Comparative Example 1 of Table 2.

[0065]

Table 1

[0066] [Evaluation Method] (1) Viscosity: The viscosity at 25°C of the compositions obtained in the examples and comparative examples was measured in accordance with JIS K 6833-1 and JIS K 7117-1 using a viscometer TVB-10H (manufactured by Toki Sangyo Co., Ltd.).

[0067] (2) Young's Modulus: The Young's modulus of the cured products of the compositions obtained in the examples and comparative examples was measured. A liquid curable resin composition was applied onto a glass plate using an applicator bar with a thickness of 381 μm, and this was cured by irradiating ultraviolet light with an energy of 1 J / cm 2 in air. A test film was obtained by peeling it from the glass plate. After allowing this cured film to stand at a temperature of 23°C and a relative humidity of 50% for a predetermined time, strip-shaped samples were prepared such that the extension part had a width of 6 mm and a length of 25 mm. A tensile test was performed on these strip-shaped samples under the same temperature and relative humidity conditions using a tensile tester 5542C4600 (manufactured by Instron Japan Co., Ltd.) in accordance with JIS K7161-1. The tensile speed was 1 mm / min, and the Young's modulus was determined from the tensile strength at a strain of 2.5%.

[0068] (3) Glass Adhesion: The glass adhesion of the cured products of the compositions obtained in the examples and comparative examples was measured. A liquid curable resin composition was applied onto a glass plate using an applicator bar with a thickness of 381 μm, and this was cured by irradiating ultraviolet light with an energy of 1 J / cm 2Ultraviolet rays of energy were irradiated to cure it, and a test film was obtained. After allowing this cured film to stand for a predetermined time at a temperature of 23°C and a relative humidity of 50%, a strip-shaped sample was prepared such that the extension part had a width of 10 mm and a length of 50 mm. Using a tensile testing machine 5542C4600 (manufactured by Instron Japan Co., Ltd.), a glass adhesion test was conducted on this strip-shaped sample in accordance with JIS Z 0237 under the same temperature and relative humidity conditions. The tensile speed was 50 mm / min, and the glass adhesion was determined from the tensile strength after 30 seconds.

[0069] The results obtained from the above evaluation are shown in Tables 2 and 3 below.

[0070]

Table 2

[0071] Note that the terminal structures of the oligomers shown in Table 2 are as follows. *-NH-CO-S-(CH2)3-Si(OMe)3 Formula (III) *-NH-CO-NH-(CH2)3-Si(OMe)3 Formula (IV) *-NH-CO-NH-(CH2)3-Si(OEt)3 Formula (V) In the above formulas (III), (IV) and (V), "Me" is a methyl group, "Et" is an ethyl group, and "*" indicates a bond.

[0072]

Table 3

Claims

1. A composition for forming an optical fiber coating layer, containing a compound having a structure represented by the following formula (I): *-NH-CO-N(R １ )-R ２ -SiR ３ ｎ -(OR ４ ) ３－ｎ (I) [wherein, R １ is a hydrogen atom or a C1-10 alkyl group, R ２ is a C ２－１０ alkylene group, R ３ is a C1-10 alkyl group, R ４ is a C １－６ alkyl group. Here, * represents a bond, and n represents an integer of 0 or more and 2 or less] wherein the content of the compound having the structure represented by formula (I) is 0.05 parts by mass or more and less than 10 parts by mass per 100 parts by mass of the composition, and the compound having the structure represented by formula (I) is a urethane (meth)acrylate oligomer, a composition for forming an optical fiber coating layer.

2.

3. R of formula (I) ４ is C ２－６ The composition for forming an optical fiber coating layer according to claim 1, wherein the alkyl group is an alkyl group of C.

4. The composition for forming an optical fiber coating layer according to claim 1 or 2, wherein the content of the compound containing the structure represented by formula (I) is 0.05 parts by mass or more and less than 4.5 parts by mass per 100 parts by mass of the composition.

5. The composition for forming an optical fiber coating layer according to claim 3, wherein the content of the compound containing the structure represented by formula (I) is 0.4 parts by mass or more and less than 3 parts by mass per 100 parts by mass of the composition.

6. The composition for forming an optical fiber coating layer according to any one of claims 1 to 4, wherein the urethane (meth)acrylate oligomer contains one (meth)acrylate group.

7. The composition for forming an optical fiber coating layer according to any one of claims 1 to 5, further comprising a photoinitiator.

8. The composition for forming an optical fiber coating layer according to any one of claims 1 to 6, further comprising a reactive diluent monomer.

9. A cured layer formed from the composition for forming an optical fiber coating layer according to any one of claims 1 to 7.

10. An optical fiber having the cured layer according to claim 8.

11. An optical fiber ribbon or an optical fiber cable comprising two or more optical fibers according to claim 9.

12. Use of a composition for forming an optical fiber coating layer, containing a compound having a structure represented by the following formula (I): *-NH-CO-N(R １ )-R ２ -SiR ３ ｎ -(OR ４ ) ３－ｎ (I) [wherein, R １ is a hydrogen atom or a C1-10 alkyl group, R ２ is a C ２－１０ alkylene group, R ３ is a C1-10 alkyl group, R ４ is a C １－６ alkyl group. Here, * represents a bond, and n represents an integer of 0 or more and 2 or less] for forming an optical fiber coating layer, wherein the content of the compound having the structure represented by formula (I) is 0.05 parts by mass or more and less than 10 parts by mass per 100 parts by mass of the composition, and the compound having the structure represented by formula (I) is a urethane (meth)acrylate oligomer.

13.

14.

15. R of formula (I) ４ is C ２－６ The use according to claim 11 for forming an optical fiber coating layer, wherein the alkyl group is an alkyl group of C.

16. The use for forming an optical fiber coating layer according to claim 11 or 12, wherein the content of the compound containing the structure represented by formula (I) is 0.05 parts by mass or more and less than 4.5 parts by mass per 100 parts by mass of the composition.

17. Use for forming an optical fiber coating layer according to claim 13, wherein the content of the compound containing the structure represented by formula (I) is 0.4 parts by mass or more and less than 3 parts by mass per 100 parts by mass of the composition.

15. Use for forming an optical fiber coating layer according to any one of claims 11 to 14, wherein the urethane (meth) acrylate oligomer consists of a single (meth) acrylate group.

16. Use for forming an optical fiber coating layer according to any one of claims 11 to 15, further comprising a photoinitiator.

17. Use for forming an optical fiber coating layer according to any one of claims 11 to 16, further comprising a reactive diluent monomer.

18. Placing the composition for forming an optical fiber coating layer according to any one of claims 1 to 7 on at least a part of the surface of the glass fiber, and Curing the composition to form a coating layer, Method for manufacturing an optical fiber.

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