Photocurable resin composition, adhesive for optical fiber array, optical fiber array, and component for optical communication

Abstract

The purpose of the present invention is to provide a photocurable resin composition exhibiting excellent curing speed and high heat resistance. More specifically, the purpose is to provide a photocurable resin composition which exhibits, as an adhesive (6) for fixing a substrate (2) on which a V-groove (3) is formed, an exposed optical fiber core wire (5), and a lid plate (4), sufficient curability despite having a complicated structure and being less exposed to light, the photocurable resin composition also having high heat resistance enabling resistance to a reflow step. This photocurable resin composition contains (A) an epoxy resin, (B) a photoacid generator, and (C) an antioxidant.

Description

Photocurable resin composition, adhesive for optical fiber array, optical fiber array and optical communication component

[0001] The present invention relates to a photocurable resin composition, an adhesive for optical fiber arrays, an optical fiber array, and an optical communication component.

[0002] Patent Document 1 describes an active energy ray-curable pressure-sensitive adhesive composition containing a urethane (meth)acrylate resin [A] having a specific structure, which is obtained by reacting a terminal isocyanate group-containing compound, which is a reaction product of a hydrogenated polybutadiene polyol (a1) and a polyisocyanate (a2), with a hydroxyl group-containing (meth)acrylate (a3), and an aliphatic or alicyclic alkyl acrylate [B] having 6 or more carbon atoms.

[0003] Japanese Patent Application Publication No. 2002-309185

[0004] BACKGROUND ART There is a demand for faster signal propagation and energy savings, and in various electronic circuits, optoelectronic hybrid boards have been developed in which part of the circuit is replaced from conductive wiring such as copper to optical wiring using optical waveguides.

[0005] Meanwhile, optical fibers have become widely used, particularly in the field of communications. Optical fiber communications employ optical fiber ribbons, in which multiple optical fibers are arranged in parallel and surrounded by a coating resin layer. To connect the optical fiber ribbons to light-receiving elements, light-emitting elements, and various terminal devices, the coating resin layer at the ends of the optical fiber ribbons is typically removed to expose the ends of the multiple optical fibers. The exposed optical fibers are then precisely aligned and fixed in V-grooved grooves on a substrate, and a cover covering the exposed optical fibers is attached with an adhesive, resulting in an optical fiber array in which multiple optical fibers are arranged at predetermined intervals.

[0006] However, when the conventional optical fiber array is mounted on an optoelectronic hybrid board, the adhesive can peel off due to the heating of the optoelectronic hybrid board during the solder reflow process, and high heat resistance is required for the fixing adhesive.

[0007] An object of the present invention is to provide a photocurable resin composition having an excellent curing rate and high heat resistance. More specifically, an object of the present invention is to provide a photocurable resin composition that can be used as an adhesive to secure a V-groove-formed substrate, an exposed optical fiber, and a lid, and that exhibits sufficient curing properties despite having a complex structure that is difficult to expose to light, and that has high heat resistance sufficient to withstand a solder reflow process.

[0008] As a result of extensive research into solving the above problems, the present inventors have found that a resin composition having a specific composition can solve the above problems, and have arrived at the present invention.

[0009] That is, the present invention relates to the following items [1] to [8]. [1] A photocurable resin composition containing an epoxy resin (A), a photoacid generator (B), and an antioxidant (C). [2] The photocurable resin composition according to item [1], having a viscosity of 200 to 3,000 mPa·s. [3] The photocurable resin composition according to item [1] or [2], wherein the epoxy resin (A) contains an alicyclic epoxy resin. [4] The photocurable resin composition according to item [1] to [3], wherein the amount of the photoacid generator (B) is 0.1 to 5.0 parts by mass, relative to 100 parts by mass of the total amount of the epoxy resin (A). [5] The photocurable resin composition according to item [1] to [4], wherein the photoacid generator (B) is a sulfonium salt-based compound. [6] The photocurable resin composition according to item [1] to [5], wherein the antioxidant (C) contains at least one selected from the group consisting of a phenol-based antioxidant (C-1) and a phosphite-based antioxidant (C-2). [7] An adhesive for optical fiber arrays, comprising the photocurable resin composition according to any one of [1] to [6]. [8] An optical fiber array in which optical fibers are fixed on a substrate with the adhesive for optical fiber arrays according to [7]. [9] The photocurable resin composition according to any one of [1] to [6], which is used for any of an adhesive for fixing microlenses, an adhesive for assembling optical connectors, an adhesive for fixing optical filters, an adhesive for fixing fiber array roots, an adhesive for optical path coupling, a precision adhesive, a sealing material for optical components, and a resin for forming optical waveguides.

[10] An optical communication component having a cured product of the photocurable resin composition according to any one of [1] to [6].

[0010] The resin composition of the present invention has good curability and heat resistance. More specifically, it does not peel off even in processes requiring high temperatures or in long-term reliability tests, and has excellent transparency, so it can be applied to many fields, such as optical components, various coating fields such as inks, plastic paints, paper printing, metal coatings, and furniture paints, linings, and also insulating varnishes, insulating sheets, laminates, printed circuit boards, resist inks, semiconductor encapsulants, and air gap fillers (fillers for the gaps between a display device and a surface panel) in displays such as touch panel type image displays.

[0011] FIG. 2 is a longitudinal cross-sectional view of the optical fiber array cut in a direction perpendicular to the optical fiber cores.

[0012] The photocurable resin composition of the present invention contains an epoxy resin (A), a photoacid generator (B), and an antioxidant (C).

[0013] The viscosity of the photocurable resin composition of the present invention at 25°C is preferably 200 to 3,000 mPa·s, and more preferably 300 to 2,000 mPa·s. By setting the viscosity at 25°C to 200 mPa·s or more, workability during coating is improved. On the other hand, by setting the viscosity at 25°C to 3,000 mPa·s or less, workability during coating tends to be improved and peeling due to uneven adhesion tends to be less likely to occur. The viscosity of the photocurable resin composition of the present invention at 25°C can be measured using an E-type viscometer (RE105, manufactured by Toki Sangyo Co., Ltd.) under the following conditions: a cone angle relative to the plate: 3°, a cone radius R: 7.7 mm, a temperature: 25°C, and a cone rotation speed: 0.5 to 10 rpm.

[0014] Examples of the epoxy resin (A) used in the photocurable resin composition of the present invention include epoxidized novolac resins of phenols and aldehydes, such as phenol novolac epoxy resins and orthocresol novolac epoxy resins; diglycidyl ethers of bisphenol A, bisphenol F, bisphenol S, alkyl-substituted bisphenols, etc.; glycidylamine epoxy resins obtained by reacting epichlorohydrin with polyamines such as diaminodiphenylmethane and isocyanuric acid; alicyclic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; diglycidyl isocyanurate; triglycidyl isocyanurate; silsesquioxane compounds; and the like. These may be used alone or in combination of two or more. Among these epoxy resins, alicyclic epoxy resins are preferred because they have a fast curing rate.

[0015] Specific examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide (registered trademark) 2021P (trade name)), 4,4'-bis(1,2-epoxycyclohexane), 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylate, 6-methyl-3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4 -epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-metadioxane, bis(3,4-epoxycyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexylcarboxylate, methylenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylenebis(3,4-epoxy cyclohexanecarboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl-3,4-epoxycyclohexane, 1,2-epoxy-2-epoxyethylcyclohexane, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, 2,4-di[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-2,4,6,6,8,8-hexamethyl-cyclotetrasiloxane, 4,8-di[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-2,4,6,6,8,8-hexamethyl-cyclotetrasiloxane bicyclo[4,1,0]heptyl})ethyl]-2,2,4,6,6,8-hexamethyl-cyclotetrasiloxane, 2,4-di[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-6,8-dipropyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, 4,8-di[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-2,6-dipropyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, 2,4,8-tri[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-2,4,6,6,Examples include 8-pentamethyl-cyclotetrasiloxane, 2,4,8-tri[2-(3-{oxabicyclo[4,1,0]heptyl})ethyl]-6-propyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis{2-(3,4-epoxycyclohexyl)ethyl}-cyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-bis[2-(7-oxabicyclo[4,1,0]hept-3-yl)ethyl]disiloxane, both-end / alicyclic epoxy-modified silicone oil (X-22-169AS, X-22-169B: Shin-Etsu Chemical Co., Ltd.), and side-chain / alicyclic epoxy-modified silicone oil (KF-102: Shin-Etsu Chemical Co., Ltd.). These may be used alone or in combination of two or more. The alicyclic epoxy resin used in the present invention is preferably liquid at room temperature and has a viscosity of 4000 mPa·s or less at 25°C. From the viewpoint of heat resistance, it is also preferable to contain an alicyclic epoxy resin having a siloxane skeleton.

[0016] The epoxy resin (A) in the photocurable resin composition is contained in an amount of preferably 30 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 70 parts by mass or more, relative to the total amount (100 parts by mass) of the resin composition.

[0017] The amount of each epoxy resin in the epoxy resin (A) is not particularly limited, but the amount of the alicyclic epoxy resin having a siloxane skeleton is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, relative to the total amount (100 parts by mass) of the epoxy resin (A).

[0018] The photoacid generator (B) contained in the photocurable resin composition of the present invention is a compound that generates cations upon irradiation with radiation such as ultraviolet light, far ultraviolet light, excimer lasers such as KrF and ArF, X-rays, and electron beams, and the cations can serve as polymerization initiators. Examples of the photoacid generator (B) include sulfonium salt compounds, iodonium salt compounds, diazonium salt compounds, and ammonium salt compounds. These may be used alone or in combination of two or more.

[0019] Specific examples of the sulfonium salt compound include [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium tris(pentafluoroethyl)trifluorophosphate, (4-hydroxyphenyl)methylbenzylsulfonium tetrakis(pentafluorophenyl)borate, 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium tris(pentafluoroethyl)trifluoro phosphate, diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, [biphenyl]-4-yl[4-[[biphenyl]-4-ylthio]phenyl](phenyl)sulfonium tetrakis(pentafluorophenyl)borate, [biphenyl]-4-yl[4-[[biphenyl]-4-ylthio]phenyl](phenyl)sulfonium tetrakis(pentafluorophenyl)gallate, and the like. Examples of trade names include CPI-110P, CPI-110A, CPI-110B, CPI-210S, CPI-6976, CPI-310B, CPI-310FG, CPI-200K, VC-1S, VC-1FG, CPI-410S, CPI-410B, and ES-1B manufactured by San-Apro Ltd.; WPAG-336, WPAG-367, WPAG-370, WPAG-469, and WPAG-638 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; and TPS-TF, TPS-CS, and TPS-PFBS manufactured by Toyo Gosei Co., Ltd.

[0020] Specific examples of the iodonium salt compounds include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis(pentafluorophenyl)borate, bis(dodecylphenyl)iodonium hexafluorophosphate, bis(dodecylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium tetrafluoroborate, bis(dodecylphenyl)iodonium tetrakis(pentafluorophenyl)borate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium hexafluorophosphate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium hexafluoroantimonate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium tetrafluoroborate, and 4-methylphenyl-4-(1-methylethyl)phenyliodonium tetrakis(pentafluorophenyl)borate.

[0021] Specific examples of the diazonium salt compounds include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis(pentafluorophenyl)borate.

[0022] Specific examples of the ammonium salt compounds include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2-cyanopyridinium tetrakis(pentafluorophenyl)borate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluorophosphate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluoroantimonate, 1-(naphthylmethyl)-2-cyanopyridinium tetrafluoroborate, and 1-(naphthylmethyl)-2-cyanopyridinium tetrakis(pentafluorophenyl)borate.

[0023] Because the photoacid generator (B) has the ability to absorb light, if a large amount of component (B) is used (for example, an amount exceeding 5.0 parts by mass), the light used during curing will not be able to penetrate deep enough. On the other hand, if a small amount is used (for example, less than 0.1%), it will be difficult to obtain a sufficient curing rate. The proportion of photoacid generator (B) added is usually 0.1 to 5.0 parts by mass, preferably 0.5 to 2.0 parts by mass, relative to the total amount (100 parts by mass) of epoxy resin (A).

[0024] The antioxidant (C) contained in the photocurable resin composition of the present invention is a compound for preventing decomposition and deterioration due to heat and light. Examples of the antioxidant (C) include phenol-based antioxidants (C-1), phosphite-based antioxidants (C-2), thioether-based antioxidants, and amine-based antioxidants.

[0025] Specific examples of the phenolic antioxidant (C-1) include dibutylhydroxytoluene, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6- Examples of such hydroxyphenyl propionates include hexanediol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 2,4-bis[(octylthio)methyl-O-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], and the like.

[0026] Those having one or less thioether bond per molecule are preferred, and particularly dibutylhydroxytoluene, pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2'-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethyleneglycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], ester], 1,6-hexanediol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] are preferred.

[0027] Specific examples of the phosphite ester-based antioxidant (C-2) include triphenyl phosphite, diisooctyl phosphite, heptakis(dipropylene glycol) triphosphite, triisodecyl phosphite, diphenyl isooctyl phosphite, diisooctylphenyl phosphite, diphenyl tridecyl phosphite, triisooctyl phosphite, trilauryl phosphite, diphenyl phosphite, tris(dipropylene glycol) phosphite, and dioleyl phosphite. halogen phosphite, trilauryl trithiophosphite, bis(tridecyl)phosphite, tris(isodecyl)phosphite, tris(tridecyl)phosphite, diphenyldecyl phosphite, dinonylphenylbis(nonylphenyl)phosphite, poly(dipropylene glycol)phenyl phosphite, tetraphenyldidipropylene glycol diphosphite, trisnonylphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris (2,4-di-tert-butyl-5-methylphenyl)phosphite, tris[2-tert-butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl]phosphite, tri(decyl)phosphite, octyldiphenylphosphite, di(decyl)monophenylphosphite, a mixture of distearyl pentaerythritol and calcium stearate, alkyl(C10)bisphenol A phosphite, bis(2,4-di-tert tetra(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite, tetrakis(2,4-di-tert-butylphenyl)biphenylene diphosphonite, and the like.The phosphite ester-based antioxidant (C-2) is preferably one having one or more aromatic rings in the molecule, and examples thereof include triphenyl phosphite, diphenyl isooctyl phosphite, diisooctylphenyl phosphite, diphenyl tridecyl phosphite, diphenyl phosphite, diphenyl decyl phosphite, dinonylphenyl bis(nonylphenyl) phosphite, poly(dipropylene glycol) phenyl phosphite, tetraphenyl didipropylene glycol diphosphite, trisnonylphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butyl-5-methylphenyl) phosphite, octyldiphenyl phosphite, di(decyl)monophenyl phosphite, alkyl(C10) bisphenol A phosphite, and bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite.

[0028] These may be used alone or in combination of two or more. The antioxidant (C) preferably contains one or more selected from either a phenol-based antioxidant (C-1) or a phosphite-based antioxidant (C-2). From the viewpoint of heat resistance, it is preferable to use a phenol-based antioxidant (C-1) and a phosphite-based antioxidant (C-2) in combination.

[0029] The amount of the antioxidant (C) contained in the resin composition may be, for example, 0.01 to 5 parts by mass, and preferably 0.1 to 3 parts by mass, relative to the total amount (100 parts by mass) of the epoxy resin (A).

[0030] The curable resin composition of the present invention may contain, as necessary, a plasticizer, a sensitizer, a leveling agent, a filler, a silane coupling agent, a colorant, a thickener, an antifoaming agent, and the like.

[0031] Specific examples of plasticizers include acrylic polymers, acrylic oligomers, phthalates, phosphates, glycol esters, citrate esters, aliphatic dibasic acid esters, fatty acid esters, epoxy plasticizers, castor oils, terpene resins, hydrogenated terpene resins, rosin resins, hydrogenated rosin resins, liquid terpenes, hydroxyl-containing acrylic polymers, hydroxyl-containing hydrogenated polybutadienes, polyether glycols, etc. From the viewpoint of transparency, hydrogenated rosin resins, hydroxyl-containing hydrogenated polybutadienes, hydrogenated polybutadienes, acrylic polymers, hydroxyl-containing acrylic polymers, polybutene, and liquid terpenes are preferred.

[0032] Specific examples of the sensitizer include thioxanthone compounds, 2,2-dimethoxy-1,2-diphenylethan-1-one, benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide.

[0033] Specific examples of the leveling agent include fluorine-based leveling agents (Ftergent (registered trademark) 100, 300, 251, 222F, 710FL, 601AD: manufactured by Neos Corporation), silicone-based leveling agents (Disparlon (registered trademark) 711EF, 1761, LS-001, LS-460: manufactured by Kusumoto Chemicals Co., Ltd., BYK (registered trademark) -302, BYK-307, BYK-322, BYK-323, BYK-326, BYK-327, BYK-329, BYK-331, BYK-332, BYK-333, BYK-334, BYK-335, BYK-336, BYK-337, BYK-338, BYK-339, BYK-340, BYK-341, BYK-342, BYK-343, BYK-344, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-349, BYK-350, BYK-351, BYK-352, BYK-353, BYK-354, BYK-355, BYK-356, BYK-357, BYK-358, BYK-359, BYK-359, BYK-359, BYK-359, BYK-359, BYK-359, BYK-351, BYK-352, BYK-353, BYK-354, BYK-355, BYK-356, BYK BYK-333, BYK-345, BYK-348, BYK-349, BYK-377, BYK-378, BYK-3420, BYK-3450, BYK-3451, BYK-3455, BYK-3456, BYK-3760: BYK Japan Co., Ltd.), acrylic leveling agents (Disparlon 1970, 230, LF-1980: Kusumoto Chemicals Co., Ltd., BYK-350, BYK-356, BYK-361N: BYK Japan Co., Ltd.). These leveling agents can be used alone or in combination of two or more. The amount of the leveling agent added is preferably 0.01 to 1 part by mass relative to the total amount (100 parts by mass) of the photocurable resin composition of the present invention.

[0034] Specific examples of fillers include silica (e.g., natural silica, fused silica, amorphous silica, hollow silica, etc.), aluminum compounds (e.g., boehmite, aluminum hydroxide, alumina, aluminum nitride, etc.), boron compounds (e.g., boron nitride, etc.), magnesium compounds (e.g., magnesium oxide, magnesium hydroxide, etc.), calcium compounds (e.g., calcium carbonate, etc.), molybdenum compounds (e.g., molybdenum oxide, zinc molybdate, etc.), barium compounds (e.g., barium sulfate, barium silicate, etc.), talc (e.g., natural talc, calcined talc, etc.), mica, glass (e.g., short fiber glass, spherical glass, finely powdered glass (e.g., E-glass, T-glass, D-glass, etc.), etc.), silicone powder, fluororesin fillers, urethane resin fillers, (meth)acrylic resin fillers, polyethylene fillers, styrene-butadiene rubber, and silicone rubber. These fillers can be used alone or in combination of two or more. These fillers may be surface-treated with a silane coupling agent or the like, which will be described later.

[0035] Specific examples of the silane coupling agent include epoxy-based silane coupling agents (e.g., 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), vinylsilane-based silane coupling agents (e.g., vinyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, etc.), amine-based silane coupling agents (e.g., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, bis-(trimethoxysilylpropyl)amine, etc.), phenylsilane-based silane coupling agents, and imidazole silane-based silane coupling agents. These may be used alone or in combination of two or more.

[0036] The light (active energy rays) used for the photoirradiation may be any light that promotes the polymerization reaction of the photocurable composition, and any of infrared light, visible light, ultraviolet light, X-rays, electron beams, α-rays, β-rays, γ-rays, etc. can be used. Among these, ultraviolet light is preferred because of its excellent handleability. For example, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc, a metal halide lamp, sunlight, an LED lamp, a UV-LED, a laser, etc. can be used for the ultraviolet irradiation.

[0037] The photocurable resin composition is widely applicable to optical components. More specifically, since the photocurable resin composition does not peel off even in processes requiring high temperatures and in long-term reliability tests and has excellent transparency, it is widely applicable to optical components such as adhesives for fixing V-grooves in optical fiber arrays, adhesives for fixing microlenses, adhesives for assembling optical connectors, adhesives for fixing optical filters, adhesives for fixing the base of fiber arrays, adhesives for optical path coupling, precision adhesives, sealing materials for optical components, and resins for forming optical waveguides.

[0038] The reliability of the photocurable resin composition can be evaluated by the following method. Two glass plates are bonded together using the resin composition. At this time, a 50 μm thick polyimide tape is sandwiched between the two glass plates as a spacer to control the film thickness of the composition. ２ The photocurable resin composition is cured by irradiating it with light of 1000 W. The composition is then left in a pressure cooker tester in a saturated steam atmosphere at a temperature of 121°C and a pressure of 2 atm for 24 hours, and the heat resistance of the cured film is evaluated based on whether or not the cured film peels off from the glass plate. ◯: No peeling from the glass plate ×: Peeling from the glass plate

[0039] The photocurable resin composition is suitable for use as an adhesive for optical fiber arrays, such as those used to connect multiple optical fibers to optical waveguides in optical waveguide elements in optical communications. More specifically, the present invention relates to an adhesive 6 for fixing a V-groove substrate 2, optical fibers 5, and a cover plate 4 in an optical fiber array 1, such as that shown in FIG. 1 (an adhesive for fixing V-grooves in optical fiber arrays). The optical fiber array 1 is used to connect and fix multiple optical fibers 5 to the end faces of the optical waveguides. The components of the optical fiber array 1 (the V-groove substrate 2 (a plate having V-grooves 3) and the cover plate 4) allow the multiple optical fibers 5 to be aligned with high precision to match the spacing between the optical waveguides, and the multiple optical fibers 5 can be optically aligned and fixed collectively. A typical optical fiber array 1 includes a glass substrate (V-groove substrate 2) with a highly accurate V-groove, a cover plate 4 on which optical fibers 5 are placed, with their coatings removed. The glass substrate 2 serves as the cover plate 4, and the cover plate 4 presses the optical fibers 5 against the slope of the V-groove 6 directly above the optical fibers, ensuring close contact. Furthermore, the coatings of the optical fibers extending on the opposite side of the optical connection surface are covered with a protective resin.

[0040] The optical fiber array 1 can be produced by placing optical fiber cores 5 on a V-groove substrate 2 having a V-groove 3 formed thereon, covering it with a cover plate 4, injecting the photocurable resin composition so that it is aligned with the optical fiber cores 5, and then irradiating it with active energy rays to cure it. After covering it with the cover plate 4, it is preferable to press it down from above to temporarily fix it in place.

[0041] The present invention will be described in more detail below with reference to examples. These examples are merely illustrative examples for suitably explaining the present invention, and are not intended to limit the present invention in any way.

[0042] Examples 1 to 8 and Comparative Example 1 (Preparation of Photocurable Resin Compositions) Compositions were obtained by blending the components according to the formulation shown in Table 1 below. The following materials were used for each component. The blending amounts in the table represent parts by mass of each component.

[0043] (Epoxy resin components) A-1: ​​2,4,6,8-tetramethyl-2,4,6,8-tetrakis{2-(3,4-epoxycyclohexyl)ethyl}-cyclotetrasiloxane (KR-470 (manufactured by Shin-Etsu Chemical Co., Ltd.)) A-2: 1,1,3,3-tetramethyl-1,3-bis[2-(7-oxabicyclo[4,1,0]hept-3-yl)ethyl]disiloxane (X-40-2669 (manufactured by Shin-Etsu Chemical Co., Ltd.)) A-3: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P (manufactured by Daicel Corporation))

[0044] (Photoacid generator) Sulfonium salt compound B: CPI-310FG (manufactured by San-Apro Co., Ltd.)

[0045] (Antioxidants) Phenolic antioxidant C-1: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (IRGANOX (registered trademark) 1076 (manufactured by BASF Japan Ltd.)) Phenolic antioxidant C-2: thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (IRGANOX 1035 (manufactured by BASF Japan Ltd.)) Phosphite ester-based antioxidant C-3: octyl diphenyl phosphate (ADK STAB (registered trademark) C (ADEKA Corporation)) Phosphite ester-based antioxidant C-4: triphenyl phosphite (ADK STAB TPP (ADEKA Corporation))

[0046] (Plasticizer) D: KE-311 (manufactured by Arakawa Chemical Industries, Ltd.)

[0047] (Viscosity of Photocurable Resin Composition) Using an E-type viscometer (RE105, manufactured by Toki Sangyo Co., Ltd.), the viscosity of the photocurable resin composition was measured under the following conditions: cone angle to the plate: 3°, cone radius R: 7.7 mm, temperature: 25°C, and cone rotation speed: 0.5 to 10 rpm. The viscosities of the photocurable resin compositions of Examples 1 to 8 and Comparative Example 1 were all lower than 2000 mPa s.

[0048] (Evaluation of curability of photocurable resin composition) The photocurable resin composition was applied onto a glass plate using a 50 μm applicator, and the applied curability was 3000 mJ / cm ２ A cured product was obtained by irradiating the film with light. ◯: Cured ×: Uncured

[0049] (Evaluation of Heat Resistance of Photocurable Resin Composition) Two glass plates were bonded together using the resin composition. At this time, a 50 μm thick polyimide tape was sandwiched between the two glass plates as a spacer to control the film thickness of the composition. ２ The cured film was heated in an oven at 250°C for 30 minutes, and the heat resistance was evaluated based on whether or not the cured film peeled off from the glass plate. ◯: No peeling from the glass plate ×: Peeling from the glass plate

[0050]

[0051] The above results demonstrate that the photocurable resin composition of the present invention has excellent curability and heat resistance. Furthermore, all of the photocurable resin compositions of the present invention had a viscosity of less than 2000 mPa·s. Therefore, the resin composition of the present invention does not peel off even in processes requiring high temperatures or in long-term reliability tests, and can be applied to a wide range of fields, including optical component applications, various coating fields such as inks, plastic paints, paper printing, metal coatings, and furniture paints, linings, and even in the electronics field, such as insulating varnishes, insulating sheets, laminates, printed circuit boards, resist inks, semiconductor encapsulants, and air gap fillers (fillers for the gaps between a display device and a surface panel) for display devices such as touch panel-type image display devices.

Claims

1. A photocurable resin composition containing an epoxy resin (A), a photoacid generator (B), and an antioxidant (C).

2. The photocurable resin composition according to claim 1, which has a viscosity of 200 to 3,000 mPa·s.

3. The photocurable resin composition according to claim 1, wherein the epoxy resin (A) comprises an alicyclic epoxy resin.

4. The photocurable resin composition according to claim 1, wherein the amount of the photoacid generator (B) is 0.1 to 5.0 parts by mass when the total amount of the epoxy resin (A) is 100 parts by mass.

5. The photocurable resin composition according to claim 1, wherein the photoacid generator (B) is a sulfonium salt compound.

6. The photocurable resin composition according to claim 1, wherein the antioxidant (C) comprises at least one selected from the group consisting of a phenol-based antioxidant (C-1) and a phosphite-based antioxidant (C-2).

7. An adhesive for optical fiber arrays, comprising the photocurable resin composition according to any one of claims 1 to 6.

8. An optical fiber array in which optical fibers are fixed onto a substrate with the adhesive for optical fiber arrays according to claim 7.

9. The photocurable resin composition according to any one of claims 1 to 6, which is used as an adhesive for fixing microlenses, an adhesive for assembling optical connectors, an adhesive for fixing optical filters, an adhesive for fixing the base of fiber arrays, an adhesive for optical path coupling, a precision adhesive, a sealing material for optical components, or a resin for forming optical waveguides.

10. An optical communication component having a cured product of the photocurable resin composition according to any one of claims 1 to 6.

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