JP6774916B2 - Coating material for optical fiber, coating optical fiber, and method for manufacturing coated optical fiber - Google Patents

Description

The present invention relates to a coating material for an optical fiber, a coated optical fiber containing the coating material, and a method for manufacturing the coated optical fiber.

An optical fiber is generally manufactured by coating the outer periphery of a glass optical fiber drawn from a preform (also referred to as an optical fiber base material) with an ultraviolet curable resin and curing it by irradiation with ultraviolet rays. The coating layer of the optical fiber prevents the glass optical fiber, which is a waveguide, from breaking, prevents the ingress of dust and moisture, and the glass optical fiber is slightly deformed (micro) by the force applied from the outside of the optical fiber. The purpose is to prevent the transmission loss of light caused by bending). In order to achieve these objectives, a high interfacial adhesion between the glass optical fiber and the coating layer is required.

Optical fibers are used in various environments including outdoors. Therefore, it is desirable that the interfacial adhesion between the glass optical fiber and the coating layer is maintained even in a high humidity atmosphere. However, the ultraviolet curable resin suitable for the coating layer of the optical fiber does not adhere strongly to the surface of the glass as it is. Further, when moisture enters the coating layer, the adhesive force between the glass optical fiber and the coating layer is significantly reduced.

In order to improve the interfacial adhesion between the glass optical fiber and the coating layer, for example, the techniques described in Patent Documents 1 and 2 add a silane coupling agent to a coating material containing an ultraviolet curable resin. The silane coupling agent reacts or interacts with the surface of the glass optical fiber by a hydrolysis reaction and a dehydration condensation reaction to improve the interfacial adhesion.

JP-A-59-92947 Special Table 2005-504698 Japanese Unexamined Patent Publication No. 2013-91575

It is known that the reaction rates of the hydrolysis reaction and the dehydration condensation reaction of the silane coupling agent generally increase in an acid or base environment. Therefore, in order to promote the reaction of the silane coupling agent and improve the interfacial adhesion, a method of making the resin composition used as the coating material acidic or basic can be considered.

However, when the resin composition is made acidic, the viscosity becomes very high, and it cannot be uniformly applied to the glass optical fiber. Further, when the resin composition is made basic, the glass optical fiber is damaged, so that the strength of the glass optical fiber is lowered. Further, when the resin composition is made acidic or basic, the reaction of the silane coupling agent naturally proceeds during storage, and the resin composition becomes cloudy. That is, in the method of making the resin composition acidic or basic, it is difficult to handle the resin composition, so that there is a problem that the production of the coated optical fiber becomes more difficult than before.

The technique described in Patent Document 3 promotes the reaction of the silane coupling agent by applying an acid-imparting substance to the surface of the glass optical fiber instead of making the resin composition itself acidic. However, in this method, the equipment is easily deteriorated by the acid-imparting substance, and it is difficult to control the coating amount of the acid-imparting substance, so that there is a problem that the production of the coated optical fiber becomes more difficult than before.

The present invention has been made in view of the above-mentioned problems, and is an optical fiber coating material capable of improving the interfacial adhesion between the glass optical fiber and the coating layer and easily coating, and the coating material for optical fiber. It is an object of the present invention to provide a coated optical fiber containing a coating material and a method for producing the same.

The first aspect of the present invention is a coating material for an optical fiber, which comprises an ultraviolet curable resin, a silane coupling agent, and a thermoacid generator that generates acid by heat, and is formed on a glass substrate. The glass adhesion is 2.0 N / m or more when a) cured at a temperature higher than the decomposition temperature of the thermal acid generator, or b) cured and then heat-aged at a temperature higher than the decomposition temperature of the thermal acid generator. ..

A second aspect of the present invention is a coated optical fiber, comprising a glass optical fiber and a coating layer for coating the glass optical fiber, and at least one layer constituting the coating layer is the coating for the optical fiber. It consists of materials.

A second aspect of the present invention is a method for producing a coated optical fiber, which comprises a step of drawing a glass optical fiber and generating an acid in the glass optical fiber by an ultraviolet curable resin, a silane coupling agent, and heat. A step of coating a coating material containing a thermal acid generator, a step of curing the ultraviolet curable resin by irradiating the glass optical fiber coated with the coating material with ultraviolet rays, and a step of applying the coating material to the heat. and heating to a temperature higher than the decomposition temperature of the acid generator, only contains the coating material, a photopolymerization initiator which initiates polymerization of the photo photoacid generator and the ultraviolet curable resin capable of generating an acid by irradiation of When included, the amount of the photoacid generator is less than or equal to the amount of the photopolymerization initiator .

According to the present invention, the interfacial adhesion between the glass optical fiber and the coating layer can be improved, and the coating material for the optical fiber can be easily coated.

It is sectional drawing of the coated optical fiber which concerns on 1st Embodiment. It is a schematic diagram of the manufacturing apparatus used in the manufacturing method of the coated optical fiber which concerns on 1st Embodiment. It is a figure which shows the flowchart of the manufacturing method of the coated optical fiber which concerns on 1st Embodiment. It is a schematic diagram of the manufacturing apparatus used in the manufacturing method of the coated optical fiber which concerns on 2nd Embodiment. It is a schematic diagram of the manufacturing apparatus used in the manufacturing method of the coated optical fiber which concerns on 2nd Embodiment. It is a schematic diagram of the manufacturing apparatus used in the manufacturing method of the coated optical fiber which concerns on 2nd Embodiment. It is a figure which shows the flowchart of the manufacturing method of the coated optical fiber which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the present embodiment. In the drawings described below, those having the same function are designated by the same reference numerals, and the repeated description thereof may be omitted.

(First Embodiment)
FIG. 1 is a cross-sectional view of the coated optical fiber 10 according to the present embodiment. As shown in FIG. 1, the coated optical fiber 10 includes a glass optical fiber 11 and a primary layer 12 (primary coating layer) and a secondary layer 13 (secondary coating layer) coated on the outer periphery of the glass optical fiber 11. It has two coating layers 14. The primary layer is a soft layer having a Young's modulus of 0.2 MPa or more and 3.0 MPa or less, and the secondary layer is a hard layer having a Young's modulus of 500 MPa or more and 2500 MPa or less. Each of the primary layer 12 and the secondary layer 13 is composed of a layer formed by irradiating a coating material for an optical fiber containing an ultraviolet curable resin with ultraviolet rays and curing the material, and has a function of protecting the glass optical fiber 11. There is.

The coated optical fiber 10 is not limited to the configuration shown in FIG. For example, the coating layer 14 may be composed of a single layer having a Young's modulus of 0.2 MPa or more and 2000 MPa or less. Further, the coating layer 14 may include three or more layers. Further, the coated optical fiber 10 may take the form of an optical fiber core wire further having a colored layer coated on the outer periphery of the coating layer 14. Further, the coated optical fiber 10 may take the form of an optical fiber tape core wire further having a collective coating layer for bundling a plurality of coated optical fibers 10.

The diameter of the glass optical fiber 11 is usually 80 μm or more and 150 μm or less, and generally 124 μm or more and 126 μm or less. The thickness of the primary layer 12 is usually 5 μm or more and 50 μm or less. The thickness of the secondary layer 13 is usually 5 μm or more and 50 μm or less. The diameter of the coated optical fiber 10 (that is, the outer diameter of the secondary layer 13) is usually 200 μm or more and 255 μm or less.

The optical fiber coating material according to the present embodiment is used as a coating material for the coating layer 14, and at least one layer constituting the coating layer 14 is the optical fiber coating material according to the present embodiment. The coating material for an optical fiber according to the present embodiment is preferably used as a coating material for a coating layer that comes into contact with a glass optical fiber 11 such as a coating material for a primary layer 12 and a coating layer 14 made of a single layer. Hereinafter, the coating material of the coating layer 14 will be described in detail as the coating material for the optical fiber according to the present embodiment. The “coating material of the coating layer 14” can mean the coating material of the primary layer 12 when the coating layer 14 includes the primary layer 12 and the secondary layer 13, and when the coating layer 14 is composed of a single layer. Can mean the coating material of the coating layer 14 in.

The coating material of the coating layer 14 contains an ultraviolet curable resin. The ultraviolet curable resin is polymerized by ultraviolet rays such as urethane (meth) acrylate such as polyether urethane (meth) acrylate and polyester urethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate. It is an ultraviolet curable resin having an ethylenically unsaturated group that cures, and preferably has at least two ethylenically unsaturated groups. The ultraviolet curable resin may be a monomer, an oligomer or a polymer that starts polymerization and is cured by irradiation with ultraviolet rays, but is preferably an oligomer. These may be used alone or in combination of two or more. Here, the oligomer is a polymer having a degree of polymerization of 2 or more and 100 or less. Further, as used herein, the term "(meth) acrylate" means one or both of acrylate and methacrylate.

The polyether urethane (meth) acrylate is a reaction product of a polyol having a polyether skeleton, an organic polyisocyanate compound and a hydroxyalkyl (meth) acrylate, and is a polyether segment, a (meth) acrylate and a urethane bond. It is a compound having. Further, the polyester-based urethane (meth) acrylate has a polyester segment, a (meth) acrylate and a urethane bond like a reaction product of a polyol having a polyester skeleton and an organic polyisocyanate compound and a hydroxyalkyl (meth) acrylate. It is a compound.

Further, the ultraviolet curable resin may contain, for example, a diluting monomer, a photosensitizer, a chain transfer agent and various additives in addition to the oligomer and the photopolymerization initiator. As the diluting monomer, monofunctional (meth) acrylate or polyfunctional (meth) acrylate is used. Here, the diluting monomer means a monomer for diluting the ultraviolet curable resin.

Examples of the monofunctional (meth) acrylate or polyfunctional (meth) acrylate as the diluting monomer include the following. For example, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth). ) Di (meth) acrylates such as acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate; 2-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, glycidyl (Meta) acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydroflufreele acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) Acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) Acrylate, phosphoric acid (meth) acrylate, ethylene oxide-modified phosphoric acid (meth) acrylate, phenoxy (meth) acrylate, ethylene oxide-modified phenoxy (meth) acrylate, propylene oxide-modified phenoxy (meth) acrylate, nonylphenol (meth) acrylate, ethylene Oxide-modified nonylphenol (meth) acrylate, propylene oxide-modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolythylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl- 2-Hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (Meta) acryloyloxypropylhydrogenphthalate, 2- (meth) acryloyloxypropylhexahydrohydrogenphthalate, 2- (meth) acryloyloxypropyltetrahydrohydrogenphthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl (meth) Mono (meth) acrylates such as acrylates, tetrafluoropropyl (meth) acrylates, hexafluoropropyl (meth) acrylates, octafluoropropyl (meth) acrylates, octafluoropropyl (meth) acrylates, adamantyl mono (meth) acrylates; trimethylol Propanetri (meth) acrylate, ethoxylated trimetylol propanetri (meth) acrylate, propoxylated trimetylol propanetri (meth) acrylate, tris2-hydroxyethylisocyanurate tri (meth) acrylate, glycerintri (meth) acrylate, penta Tri (meth) acrylates such as erythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylol propanetri (meth) acrylate; pentaerythritol tetra (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, di Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylol propanepenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylol propanehexa (meth) acrylate, etc. Functional (meth) acrylate; Examples thereof include polyfunctional (meth) acrylate in which a part of the (meth) acrylate is replaced with an alkyl group or ε-caprolactone.

The diluted monomer may be used alone or in combination of two or more. The amount of the diluted monomer added is preferably 100 parts by mass or less, preferably 10 to 70 parts by mass, based on 100 parts by mass of the oligomer, in consideration of the abrasion resistance of the coating film 14 obtained as the coating film. Is more preferable.

Further, the coating material of the coating layer 14 is a silane coupling agent that interacts with the surface of the glass optical fiber 11 by hydrolysis and dehydration condensation, and a thermoacid generator that generates an acid such as Lewis acid or Bronsted acid by heating. including. The acid generated from the thermal acid generator promotes hydrolysis and dehydration condensation of the silane coupling agent, and improves the adhesion between the resin contained in the coating layer 14 and the glass optical fiber 11.

[Thermal acid generator]
There are two types of acid generators, a photoacid generator that generates acid by light irradiation and a thermoacid generator that generates acid by heat. In this embodiment, a thermoacid generator is used for the purpose of generating an acid by heat. As will be described later, in the present embodiment, a photoacid generator can be used together with the thermoacid generator.

The thermoacid generator is used as a thermal latent cation initiator for thermosetting an epoxy resin or the like, and when heated to a predetermined temperature or higher, it decomposes to generate an acid. The acid generation temperature (decomposition temperature) of the thermoacid generator used in the present embodiment varies depending on the type of thermoacid generator, but is 60 ° C. or higher and 200 ° C. or lower in order to reduce the influence on the coated optical fiber 10. It is preferably 80 ° C. or higher and 150 ° C. or lower.

The thermoacid generator that can be used as the coating material of the coating layer 14 is not particularly limited as long as it generates an acid by thermal decomposition. For example, as the thermoacid generator, an onium salt-based thermoacid generator such as an organic onium salt compound in which a cation component and an anion component are paired is used. Examples of the cationic component of the thermoacid generator include various onium salt compounds such as an organic sulfonium salt compound, an organic oxonium salt compound, an organic ammonium salt compound, an organic phosphonium salt compound, and an organic iodonium salt compound. As the anionic component of the thermal acid generator, for ^{_{example, B (C 6 F 5)}} 4 -, SbF 6 -, SbF 4 -, AsF 6 -, PF 6 -, BF 4 -, CF 3 SO 3 - , etc. Can be mentioned. Further, for example, organic metal complexes such as aluminum chelate complex, iron-allene complex, titanosen complex, arylsilanol-aluminum complex, oxime sulfonate-based acid generator, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes. Diazomethane-based acid generators, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, disulfon-based acid generators, and the like also function as thermoacid generators. These may be used alone, or may be used in combination of two or more.

Commercially available thermal acid generators include, for example, K-PURE (registered trademark, hereinafter omitted) CXC-1612, K-PURE CXC-1613, K-PURE CXC-1614, K-PURE CXC-1738, K-PURE. CXC-2700, K-PURE TAG-2689, K-PURE TAG-2681, K-PURE TAG-2685, K-PURE TAG-2690, K-PURE TAG-2712, K-PURE TAG-2713 (KING INDUSTRIES) (Product name), Sun Aid SI-45L, Sun Aid SI-60L, Sun Aid SI-80L, Sun Aid SI-100L, Sun Aid SI-110L, Sun Aid SI-150L (above, Sanshin Chemical Industry Co., Ltd., product name) And so on.

In order to generate an acid from the thermoacid generator, heating is performed at the acid generation temperature (decomposition temperature) of the thermoacid generator during or after the production of the coated optical fiber 10. The thermosetting agent can generate an acid by the heat from the light source at the time of curing the ultraviolet curable resin or the reaction heat of the resin itself without performing an additional step. Further, as in the second embodiment described later, an additional heating step may be set separately.

The amount of the thermal acid generator added is preferably 0.01 wt% or more and 10 wt% or less, and more preferably 0.1 wt% or more and 5 wt% or less with respect to the coating material of the coating layer 14. If it is less than this range, the amount of acid generated is small, so the effect of promoting the hydrolysis reaction and dehydration condensation reaction of the silane coupling agent is low, and it takes time to develop the adhesion between the coating layer 14 and the glass optical fiber 11. It takes. If it exceeds this range, the storage stability of the coating material may decrease. In addition, "wt%" indicates the weight percent concentration (hereinafter, the same).

In the present embodiment, since the thermoacid generator that generates acid by heat is added to the coating material of the coating layer 14, the reaction of the silane coupling agent can be promoted by applying heat during the production of the optical fiber. The coating material is easy to handle because almost no acid is generated from the thermoacid generator when no heat is applied.

[Silane coupling agent]
As the silane coupling agent, any known and publicly available silane coupling agent can be used as long as it does not interfere with the effects of the present invention. The amount of the silane coupling agent added is appropriately determined by experiments and the like. The specific compound of the silane coupling agent is not particularly limited, but for example, tetramethylsilicate, tetraethylsilicate, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl). Ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltri Methoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N -2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3 -Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris- (trimethoxysilylpropyl) isocyanurate, 3-ureidopropyltrialkoxysilane, Examples thereof include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanuppropyltriethoxysilane.

The amount of the silane coupling agent added is preferably 0.1 wt% or more and 10 wt% or less, and more preferably 0.5 wt% or more and 5.0 wt% or less with respect to the coating layer 14. Within the above range, the adhesion between the glass optical fiber 11 and the coating layer 14 is sufficient, and the storage stability of the coating material is excellent.

Further, the coating material of the coating layer 14 may contain a diluting monomer, a photopolymerization initiator, a photoacid generator, a photosensitizer, a chain transfer agent and various additives. As the diluting monomer, monofunctional (meth) acrylate or polyfunctional (meth) acrylate is used. The diluting monomer is a monomer for diluting an ultraviolet curable resin.

[Photopolymerization initiator]
The photopolymerization initiator absorbs light in the wavelength region emitted from the ultraviolet irradiation device and generates radicals to initiate polymerization in the ultraviolet curable resin. The amount of the photopolymerization initiator added is appropriately determined by experiments and the like. The photopolymerization initiator is not particularly limited, and for example, a benzyl ketal-based photopolymerization initiator, an α-hydroxyketone-based photopolymerization initiator, an α-aminoketone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like. Use an oxime ester-based photopolymerization initiator, an acridin-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an aromatic ketoester-based photopolymerization initiator, a benzoic acid ester-based photopolymerization initiator, etc. Can be done.

Examples of the benzyl ketal-based photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one.

Examples of the α-hydroxyketone-based photopolymerization initiator include 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and 2-hydroxy-2-methyl-1-phenylpropane-1. -On, 1-hydroxycyclohexylphenyl ketone, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1- [4- [4- ( 2-Hydroxy-2-methylpropionyl) benzyl] phenyl] -2-methylpropan-1-one can be mentioned.

Examples of the α-aminoketone-based photopolymerization initiator include 2-dimethylamino-2-methyl-1-phenylpropan-1-one, 2-diethylamino-2-methyl-1-phenylpropan-1-one, and 2-. Methyl-2-morpholino-1-phenylpropan-1-one, 2-dimethylamino-2-methyl-1- (4-methylphenyl) propan-1-one, 2-dimethylamino-1- (4-ethylphenyl) ) -2-Methylpropan-1-one, 2-dimethylamino-1- (4-isopropylphenyl) -2-methylpropan-1-one, 1- (4-butylphenyl) -2-dimethylamino-2- Methylpropan-1-one, 2-dimethylamino-1- (4-methoxyphenyl) -2-methylpropane-1-one, 2-dimethylamino-2-methyl-1- (4-methylthiophenyl) propane-1 -On, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1-one , 2-benzyl-2-dimethylamino-1- (4-dimethylaminophenyl) -butane-1-one, 2-dimethylamino-2-[(4-methylphenyl) methyl] -1- [4- (4) -Morfornyl) phenyl] -1-butanone.

Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and bis (2,6-dimethoxybenzoyl). )-(2,4,4-trimethylpentyl) phosphine oxide.

Examples of the oxime ester-based photopolymerization initiator include 1-phenylpropane-1,2-dione-2- (O-ethoxycarbonyl) oxime and 1-phenylbutane-1,2-dione-2- (O-methoxy). Oxime of carbonyl, 1,3-diphenylpropane-1,2,3-trione-2- (O-ethoxycarbonyl) oxime, 1- [4- (phenylthio) phenyl] octane-1,2-dione-2-( O-benzoyl) oxime, 1- [4- [4- (carboxyphenyl) thio] phenyl] propane-1,2-dione-2- (O-acetyl) oxime, 1- [9-ethyl-6- (2) -Methylbenzoyl) -9H-Carbazole-3-yl] Etanone-1- (O-acetyl) oxime, 1- [9-ethyl-6- [2-methyl-4- [1- (2,2-dimethyl-) 1,3-Dioxolan-4-yl) methyloxy] benzoyl] -9H-carbazole-3-yl] etanone-1- (O-acetyl) oxime.

Examples of the acridine-based photopolymerization initiator include 1,7-bis (acridine-9-yl) -n-heptane.

Examples of the benzophenone-based photopolymerization initiator include benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, 4-phenylbenzophenone, 4,4-dichlorobenzophenone, 4- Examples include hydroxybenzophenone, alkylated benzophenone, 3,3', 4,4'-tetrakis (t-butylperoxycarbonyl) benzophenone, 4-methylbenzophenone, dibenzylketone and fluorenone.

Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,3-diethoxyacetophenone, 4-t-butyldichloroacetophenone, benzalacetophenone, and 4-azidobenzalacetophenone.

Examples of the aromatic ketoester-based photopolymerization initiator include methyl 2-phenyl-2-oxyacetate.

Examples of the benzoic acid ester-based photopolymerization initiator include ethyl 4-dimethylaminobenzoate, hexyl 4-dimethylaminobenzoate (2-ethyl), ethyl 4-diethylaminobenzoate, and methyl 2-benzoylbenzoate. ..

Commercially available photopolymerization initiators include IRGACURE (registered trademark, omitted below) 651, IRGACURE 184, IRGACURE 1173, IRGACURE 2959, IRGACURE 127, IRGACURE 907, IRGACURE 369, IRGACURE 379, IRGACURE19, IRGACURE 379, IRGACURE. Examples thereof include IRGACURE OXE02, IRGACURE MBF, IRGACURE 754 (above, manufactured by BASF, trade name), ADEKA ARKULS (registered trademark) NCI-831 (manufactured by ADEKA Corporation, trade name) and the like.

The amount of the photopolymerization initiator added can be appropriately determined by experiments or the like as described above, but is preferably 0.01 wt% or more and 10 wt% or less, preferably 0.1 wt% or more, based on the coating material of the coating layer 14. More preferably, it is 8 wt% or less. When the amount of the photopolymerization initiator added is too small, the reaction rate of radical polymerization of the obtained resin composition, that is, the curing rate becomes low, which tends to take a long time for curing or deteriorate the curing characteristics. There is. On the other hand, when the amount added is excessive, the excessive amount of the photopolymerization initiator may reduce the deep curability of the resin layer.

[Photoacid generator]
Further, the coating material of the coating layer 14 may contain a photoacid generator. The photoacid generator absorbs the irradiated light and then decomposes to extract hydrogen from the solvent or the photoacid generator itself to generate the acid. The photoacid generator absorbs ultraviolet rays when the ultraviolet curable resin is cured to generate an acid, and the generated acid promotes hydrolysis and dehydration condensation of the silane coupling agent. However, the addition of an excessive photoacid generator may also inhibit the reaction of the photopolymerization initiator that absorbs ultraviolet rays and generates radical species. Therefore, the amount of the photoacid generator added needs to be an amount that does not impair the curability of the ultraviolet curable resin, and is preferably less than or equal to the amount of the photopolymerization initiator added, rather than the amount of the photopolymerization initiator added. Is more preferable.

The light absorbed by the photoacid generator varies depending on the type of photoacid generator, but is, for example, ultraviolet rays in the wavelength region of about 10 nm or more and 405 nm or less. It is preferable that at least a part of the wavelength region of light for curing the ultraviolet curable resin contained in the coating material of the coating layer 14 and the wavelength region of light for generating acid in the photoacid generator overlap. As a result, the ultraviolet curable resin can be cured by the light from one type of light source and the acid can be generated by the photoacid generator at the same time.

The photoacid generator that can be used as the coating material of the coating layer 14 is not particularly limited as long as it generates an acid by irradiation with light. The photoacid generator can be roughly classified into an onium salt-based photoacid generator and a nonionic photoacid generator. In this embodiment, at least one of an onium salt-based photoacid generator and a nonionic photoacid generator is used, but other types of photoacid generators may be used.

The onium salt-based photoacid generator is not particularly limited, and is, for example, an organic sulfonium salt compound, an organic oxonium salt compound, an organic ammonium salt compound, an organic phosphonium salt compound, an organic iodonium salt compound, and a hexafluoroantimonate anion. , Tetrafluoroborate anion, hexafluorophosphate anion, hexachloroantimonate anion, trifluoromethanesulphonate ion, or those having a counter anion such as fluorosulphonate ion. Counter anion, specifically, for ^{_{example, B (C 6 F 5)}} 4 -, SbF 6 -, SbF 4 -, AsF 6 -, PF 6 -, BF 4 -, CF 3 SO 3 - and the like. These may be used alone, or may be used in combination of two or more.

Commercially available onium salt-based photoacid generators include, for example, IRGACURE (registered trademark, omitted below) 250, IRGACURE 270, IRGACURE PAG 290, GSID26-1 (above, BASF, trade name), WPI-113, WPI-116, WPI-169, WPI-170, WPI-124, WPAG-336, WPAG-376, WPAG-370, WPAG-469, WPAG-638 (manufactured by Wako Pure Chemical Industries, Ltd., trade name), B2380, B2381, C1390, D2238, D2248, D2253, I0591, N1066, T1608, T1609, T2041, T2042 (all manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name), CPI-100, CPI-100P, CPI-101A, CPI -200K, CPI-210S, IK-1, IK-2 (all manufactured by Sun Appro Co., Ltd., trade name), SP-056, SP-066, SP-130, SP-140, SP-150, SP-170, SP-171, SP-172 (above, ADEKA Co., Ltd., product name), CD-1010, CD-1011, CD-1012 (above, Sartmer, product name), PI2074 (Rhodia Japan Co., Ltd., product name) First name) and so on.

The nonionic photoacid generator is not particularly limited, and for example, a phenacylsulfon-type photoacid generator, an o-nitrobenzyl ester-type photoacid generator, an iminosulfonate-type photoacid generator, and an N-hydroxyimide. Examples thereof include a sulfonic acid ester type photoacid generator. These may be used alone, or may be used in combination of two or more. Specific compounds of the nonionic photoacid generator include, for example, sulfonyldiazomethane, oxim sulfonate, imide sulfonate, 2-nitrobenzyl sulfonate, disulfon, pyrogallol sulfonate, p-nitrobenzyl-9,10-dimethoxyanthracene-2. -Sulfonate, N-sulfonyl-phenylsulfonamide, trifluoromethanesulphonic acid-1,8-naphthalimide, nonafluorobutanesulfonic acid-1,8-naphthalimide, perfluorooctanesulfonic acid-1,8-naphthalimide, penta Fluorobenzene sulfonic acid-1,8-naphthalimide, nonafluorobutane sulfonic acid-1,3,6-trioxo-3,6-dihydro-1H-11-thia-azacyclopentaanthracen-2-yl ester, nonafluoro Butane Sulfonic Acid-8-isopropyl-1,3,6-trioxo-3,6-dihydro-1H-11-thia-2-azacyclopentaanthracen-2-yl ester, 1,2-naphthoquinone-2-diazide- 5-Sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride, 1,2-benzoquinone-2-diazide-4-sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-5- Sodium Sulfonate, 1,2-naphthoquinone-2-diazide-4-sulfonate, sodium 1,2-benzoquinone-2-diazide-4-sulfonate, 1,2-naphthoquinone-2-diazide-5-sulfonic acid Potassium, 1,2-naphthoquinone-2-diazide-4-sulfonate potassium, 1,2-benzoquinone-2-diazide-4-sulfonate potassium, 1,2-naphthoquinone-2-diazide-5-sulfonate methyl, Examples thereof include methyl 1,2-benzoquinone-2-diazide-4-sulfonate.

Examples of commercially available nonionic photoacid generators include IRGACURE PAG103, IRGACURE PAG121, IRGACURE PAG203, CGI725, CGI1907 (trade names, manufactured by BASF), WPAG-145, WPAG-149, and WPAG-170. WPAG-199 (above, manufactured by Wako Pure Chemical Industries, Ltd., trade name), D2963, F0362, M1209, M1245 (above, manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name), SP-082, SP-103, SP-601 , SP-606 (all manufactured by ADEKA Co., Ltd., trade name), SIN-11 (manufactured by Sanpo Chemical Industries, Ltd., trade name), NT-1TF (manufactured by Sun Appro Co., Ltd., trade name) and the like.

The amount of the photoacid generator added is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, based on the coating material of the coating layer 14. When the amount of the photoacid generator is less than this, the progress rate of the hydrolysis reaction and the dehydration condensation reaction of the silane coupling agent is lowered because the amount of the acid generated from the photoacid generator is small, and the coating layer 14 and the coating layer 14 It takes time to develop adhesion with the glass optical fiber 11.

Further, as described above, the amount of the photoacid generator added is preferably less than or equal to the amount of the photopolymerization initiator added in the coating material of the coating layer 14, and is less than the amount of the photopolymerization initiator added. Is more preferable. When a photopolymerizer is added in a larger amount than the photopolymerization initiator, the reaction of the photopolymerization initiator that also absorbs ultraviolet rays to generate radical species is inhibited, so that the curability of the coating layer 14 is lowered. The elastic modulus may decrease. Specifically, the amount of the photoacid generator added is preferably 10 wt% or less, more preferably 5 wt% or less, based on the coating material of the coating layer 14.

[Photosensitizer]
The photosensitizer is added to the coating material of the coating layer 14 for the purpose of improving the photosensitivity of the photoacid generator. The photosensitizer preferably absorbs light in a wavelength region different from that of the photoacid generator. The photosensitizer improves the photosensitivity of the photoacid generator by absorbing light in a wavelength region that cannot be absorbed by the photoacid generator. Therefore, the absorption wavelength range of the photosensitizer and the absorption wavelength range of the photoacid generator are different, and it is preferable that the overlap between them is small.

The amount of the photosensitizer added is preferably 0.1 wt% or more and 10 wt% or less, and more preferably 0.5 wt% or more and 10 wt% or less with respect to the coating material of the coating layer 14. When the amount of the photosensitizer added is 0.1 wt% or more, the desired sensitivity can be easily obtained, and when it is 10 wt% or less, the transparency of the coating film can be easily ensured.

The photosensitizer that can be used for the coating material of the coating layer 14 is not particularly limited, and examples thereof include anthracene derivatives, benzophenone derivatives, thioxanthone derivatives, anthraquinone derivatives, and benzoin derivatives.

The specific compound of the photosensitizer is not particularly limited, but for example, 9,10-dialkoxyanthracene, 2-alkylthioxanthone, 2,4-dialkylthioxanthone, 2-alkylanthraquinone, 2,4-dialkylanthraquinone. , P, p'-diaminobenzophenone, 2-hydroxy-4-alkoxybenzophenone, benzoinether, anthraquinone, anthracene, 9,10-diphenylanthracene, 9-ethoxyanthracene, pyrene, perylene, coronen, phenanthrene, benzophenone, benzyl, Benzoin, methyl 2-benzoyl benzoate, butyl 2-benzoyl benzoate, benzoin ethyl ether, benzoin-i-butyl ether, 9-fluorenone, acetphenone, p, p'-tetramethyldiaminobenzophenone, p, p'-tetraethylaminobenzophenone , 2-Chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, phenothiazine, aclysine orange, benzoflavin, setoflavin-T, 2-nitrofluorene, 5-nitroacenaftene, benzoquinone, 2-chloro-4-nitro Anthraquinone, N-acetyl-p-nitroaniline, p-nitroaniline, N-acetyl-4-nitro-1-naphthylamine, picramid, anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1,2-benzanthraquinone , 3-Methyl-1,3-Diaza-1,9-benzanthracene, dibenzalacene, 1,2-naphthoquinone, 3,3'-carbonyl-bis (5,7-dimethoxycarbonylcoumarin), 9,10 -Dibutoxyanthracene, 9,10-dipropoxyanthracene and the like. These may be used alone, or may be used in combination of two or more.

FIG. 2 is a schematic view of a manufacturing apparatus 20 used in the method for manufacturing the coated optical fiber 10 according to the present embodiment. The optical fiber base material 21 is made of, for example, quartz-based glass, and is manufactured by a well-known method such as a VAD method, an OVD method, or a MCVD method. The end of the optical fiber base material 21 is heated by a heater 22 which is a heating device arranged around the optical fiber base material 21, melted, and drawn to be a glass optical fiber 23 (that is, the glass optical fiber of FIG. 1). 11) is pulled out.

Below the heater 22, a resin coating device 24 (die) for coating an ultraviolet curable resin on the outer circumference of the glass optical fiber 23 is provided. In the resin coating device 24, the coating material for the primary layer 12 (also referred to as the primary layer material) and the coating material for the secondary layer 13 (also referred to as the secondary layer material) are separately held. Here, at least the primary layer material is a coating material containing the above-mentioned silane coupling agent and thermoacid generator. The secondary layer material is not limited to the above-mentioned structure, and may not contain, for example, a silane coupling agent and a thermoacid generator. The primary layer material and the secondary layer material are collectively coated on the glass optical fiber 23 drawn from the optical fiber base material 21 by the resin coating device 24.

Below the resin coating device 24, an ultraviolet irradiation device 26 for irradiating the glass optical fiber 25 coated with the primary layer material and the secondary layer material with ultraviolet rays is provided. The ultraviolet irradiation device 26 includes an arbitrary ultraviolet light source such as a semiconductor light emitting element and a mercury lamp. The glass optical fiber 25 coated with the ultraviolet curable resin by the resin coating device 24 enters the ultraviolet irradiation device 26 and is irradiated with ultraviolet rays. As a result, the two layers of the ultraviolet curable resin coated on the outer periphery of the glass optical fiber 25 are cured, and the two layers of the ultraviolet curable resin become the primary layer 12 and the secondary layer 13.

In the present embodiment, acid is generated from the thermoacid generator contained in the coating material of the coating layer 14 by the heat from the light source included in the ultraviolet irradiation device 26 and the reaction heat of the resin itself. When a higher temperature is required depending on the type of the thermoacid generator, a heat source such as a heater may be provided in the ultraviolet irradiation device 26, and heating may be performed at the same time as the ultraviolet irradiation.

The glass optical fiber (that is, the coated optical fiber 10) having the primary layer 12 and the secondary layer 13 formed on the outer periphery thereof is guided by the guide roller 27 and wound by the winding device 28.

The method for manufacturing the coated optical fiber 10 according to the present embodiment uses the Wet-On-Wet method in which the primary layer 12 and the secondary layer 13 are applied and cured with one die, but the primary layer 12 and the secondary layer 13 are used. You may use the Wet-On-Dry method of applying and curing with separate dies.

FIG. 3 is a diagram showing a flowchart of a method for manufacturing the coated optical fiber 10 according to the present embodiment. First, the user installs the optical fiber base material 21 in the manufacturing apparatus 20 (step S11). Next, the heater 22 heats the optical fiber base material 21 and starts drawing the glass optical fiber 23 (step S12).

The resin coating device 24 coats the drawn glass optical fiber 23 with the primary layer material (step S13), and then coats the secondary layer material (step S14). The ultraviolet irradiation device 26 irradiates the glass optical fiber 25 coated with the primary layer material and the secondary layer material with ultraviolet rays and heats the glass optical fiber 25 (step S15). Irradiation with ultraviolet rays cures the primary layer material and the secondary layer material, and forms a coated optical fiber 10 including the primary layer 12 and the secondary layer 13. At the same time, the heat from the light source included in the ultraviolet irradiation device 26 and the reaction heat of the resin itself generate acid from the thermoacid generator contained in the coating material, and the reaction of the silane coupling agent is promoted. That is, in the present embodiment, the heating step is included in the ultraviolet irradiation step.

The coating material used for the coating layer 14 (particularly the primary layer 12) of the coated optical fiber 10 according to the present embodiment contains a thermal acid generator. Since the thermoacid generator generates an acid for the first time by heating, the acid is generated by the reaction heat at the time of UV curing of the coating material and the heating after UV irradiation. The generated acid promotes the progress of the hydrolysis reaction and the dehydration condensation reaction of the silane coupling agent, and high adhesion between the glass optical fiber 11 and the coating layer 14 can be obtained.

Further, the coating material used for the coating layer 14 (particularly the primary layer 12) of the coated optical fiber 10 according to the present embodiment may contain a photoacid generator. When a photoacid generator is contained, the photoacid generator generates an acid only by irradiation with ultraviolet rays, so that the acid is generated at the same time as the coating material is cured with ultraviolet rays. The acid generated by the photoacid generator also promotes the progress of the hydrolysis reaction and dehydration condensation reaction of the silane coupling agent, and high adhesion between the glass optical fiber 11 and the coating layer 14 can be obtained immediately after UV curing. By using not only the thermoacid generator but also the photoacid generator, the hydrolysis reaction and the dehydration condensation reaction of the silane coupling agent can be further promoted as compared with the case where only the thermoacid generator is used.

It has been reported that the light loss increases due to flooding in the conventional optical fiber core wire. When the optical fiber core wire is flooded for a long period of time, for example, the adhesion between the glass optical fiber / primary layer interface is reduced due to the flooding, and partial peeling occurs, and water accumulates in the space formed thereby and the peeling further expands. To do. Peeling occurs at the glass optical fiber / primary layer interface, and when water accumulates, a lateral pressure is applied to the glass optical fiber, resulting in an increase in light loss due to microbend. In the optical fiber core wire using the coated optical fiber 10 according to the present embodiment, since the adhesion of the glass optical fiber / primary layer interface is improved, it is possible to suppress an increase in light loss due to water immersion of the optical fiber core wire. it can.

Further, in the coated optical fiber 10 according to the present embodiment, since the adhesion of the glass optical fiber / primary layer interface is improved, the durability of the breaking strength of the glass optical fiber 11 (represented by the dynamic fatigue characteristic) is extended. Can be maintained stably over a period of time.

In a configuration in which the coating material is made acidic or basic in advance in order to promote the reaction of the silane coupling agent, there is a problem that the reaction of the silane coupling agent proceeds naturally during storage. On the other hand, when the coating material according to the present embodiment is stored in a cool and dark place, almost no acid is generated from the thermoacid generator, so that the storage stability is good. Further, even when the coating material according to the present embodiment also contains a photoacid generator, the coating material according to the present embodiment is stable in storage because almost no acid is generated from the photoacid generator if it is stored in a cool and dark place. The sex is good.

(Second Embodiment)
In the first embodiment, the ultraviolet irradiation step and the heating step are the same steps, but in the present embodiment, a heating step different from the ultraviolet irradiation step is performed. The heating step only needs to be able to heat the coating material, and is performed at any timing including before and after the coating step of applying the ultraviolet resin to the glass optical fiber to the ultraviolet irradiation step for curing. For example, the coating step, the heating step, and the ultraviolet irradiation step may be performed in this order, and the order may be changed. Further, all or part of the coating step, the heating step and the ultraviolet irradiation step may be repeated. Further, the coating step and the heating step may be performed at the same time, or the heating step and the ultraviolet irradiation step may be performed at the same time.

4 to 6 are schematic views of a manufacturing apparatus 20 used in the method for manufacturing the coated optical fiber 10 according to the present embodiment. In the manufacturing apparatus 20 of FIGS. 4 to 6, the positions of the heating apparatus 29 for heating the coating material are different from each other.

In the manufacturing apparatus 20 of FIG. 4, in addition to the configuration of the first embodiment, a tubular heating apparatus 29 is provided below the ultraviolet irradiation apparatus 26. The heating device 29 heats the glass optical fiber 25 after it has been irradiated with ultraviolet rays from the ultraviolet irradiation device 26 when it passes through the inside.

In the manufacturing apparatus 20 of FIG. 5, in addition to the configuration of the first embodiment, a heating apparatus 29 is provided so as to surround the side of the resin coating apparatus 24. The heating device 29 heats the coating material by heating the die of the resin coating device 24, and the resin coating device 24 coats the glass optical fiber 23 with the coated material in the heated state.

In the manufacturing apparatus 20 of FIG. 6, in addition to the configuration of the first embodiment, a tubular heating apparatus 29 is provided between the resin coating apparatus 24 and the ultraviolet irradiation apparatus 26. The heating device 29 heats the glass optical fiber 25 after it has been coated with the coating material by the resin coating device 24 when it passes through the inside.

The heating device 29 of FIGS. 4 to 6 includes an arbitrary heat source such as a tape heater, a ribbon heater, a rubber heater, an oven heater, a ceramic heater, an infrared irradiation unit, an ultraviolet irradiation unit, a heating wire heater, a carbon heater, and a halogen heater. The heating temperature of the heating device 29 is preferably 60 ° C. or higher and 200 ° C. or lower, and particularly preferably 80 ° C. or higher and 150 ° C. or lower, in order to suppress damage to the coated optical fiber 10.

FIG. 7 is a diagram showing a flowchart of a method of manufacturing the coated optical fiber 10 using the manufacturing apparatus 20 of FIG. Steps S11 to S15 are the same as those in the first embodiment. After irradiating the ultraviolet rays in step S15, the heating device 29 heats the coated optical fiber 10 (that is, the coating material of the coating layer 14) at a predetermined temperature (step S16).

When the manufacturing apparatus 20 of FIG. 5 is used, the heating step (step S16) is performed at the same time as the coating step (steps S13 to S14) in the flowchart of FIG. Further, when the manufacturing apparatus 20 of FIG. 6 is used, the heating step (step S16) is performed between the coating step (steps S13 to S14) and the ultraviolet irradiation step (step S15) in the flowchart of FIG. In the present embodiment, the coating step, the ultraviolet irradiation step, and the heating step are performed once, but at least a part of them may be repeated twice or more.

According to the present embodiment, even if the temperature of the ultraviolet irradiation step does not reach the decomposition temperature of the thermoacid generator, the coating material is heated to the decomposition temperature of the thermoacid generator in the heating step to generate an acid. .. As a result, the hydrolysis reaction and dehydration condensation reaction of the silane coupling agent can be promoted, and high adhesion between the glass optical fiber 11 and the coating layer 14 can be obtained.

Further, a heating step may be performed after the production of the coated optical fiber 10. Specifically, after the coated optical fiber 10 is manufactured by the manufacturing method according to the first embodiment, heating may be performed by placing the coated optical fiber 10 in a constant temperature bath set to a predetermined temperature. As a result, the effect of improving the interfacial adhesion by heating can be obtained without changing the manufacturing apparatus 20 from the first embodiment.

(Example)
Samples were prepared under the following conditions as examples and comparative examples according to the above-described embodiment, and their properties were measured.

1. 1. Formulation of coating material As the ultraviolet curable resin of the coating material, an ultraviolet curable polyether urethane acrylate resin was used. The Young's modulus was adjusted to 1.0 MPa by changing the molecular weight of the polyether moiety in the oligomer, the type and blending amount of the diluted monomer and the reactive monomer. Lucirin (registered trademark) TPO (manufactured by BASF, trade name) 3.0 wt% is used as the photopolymerization initiator, and KBM-5103 (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) 1.5 wt% as the silane coupling agent. It was used.

As a thermal acid generator to be added to the coating material, 1-naphthylmethylmethyl-p-hydroxyphenylsulfonium hexafluoroantimonate (manufactured by Sanshin Chemical Industry Co., Ltd., trade name: Sun Aid SI-60L, decomposition temperature: 60 ° C.), or 2 -Methylbenzylmethyl-p-hydroxyphenylsulfonium hexafluoroantimonate (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sun Aid SI-80L, decomposition temperature 80 ° C.) was used. In addition to SI-60L, which is a thermoacid generator, the coating materials of some examples and comparative examples include diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate, which is a photoacid generator. Sun Appro Co., Ltd., trade name CPI-101A) was added. In each Example and Comparative Example, the type and amount of the acid generator added to the coating material were set variously as shown in Table 1 below.

2. Preparation of Film The coating material according to each Example and Comparative Example was spin-coated on a plate-shaped glass base material to a thickness of 100 μm. The prepared sample was placed in a purge box to create a nitrogen atmosphere, and the ultraviolet irradiation was performed by adjusting the illuminance and speed so that the integrated light intensity was 500 mJ / cm ² (wavelength 365 nm) with a conveyor type ultraviolet irradiation device. The coating material cured by this was used as a film according to each Example and Comparative Example. As the light source of the conveyor type ultraviolet irradiation device, an electrodeless UV lamp (D valve in Table 1) or an ultraviolet irradiation unit equipped with a semiconductor light emitting element (UV-LED) having a peak wavelength of 365 ± 10 nm (in Table 1). LED) was used.

3. 3. Thermal aging For some examples, the film after ultraviolet irradiation was allowed to stand in a constant temperature bath adjusted to 80 ° C. for 24 hours, simulating the case of thermal aging after manufacturing an optical fiber.

4. Measurement of resin temperature An irreversible thermolabel (manufactured by Nichiyu Giken Kogyo Co., Ltd., 3E-60 (temperature combination 60-70) that discolors on the coating material after spin coating at a specific temperature and does not return to the original color once discolored. -80) and 3E-90 (temperature combination 90-100-110)) were attached, and the temperature indicated by the thermolabel after ultraviolet irradiation was defined as the resin temperature at the time of ultraviolet irradiation.

5. Measurement of Young's modulus The Young's modulus (tensile elastic modulus) of the film was used to determine the curability of the coating material. The films according to each Example and Comparative Example were peeled off from the glass substrate, cut into strips having a width of 6 mm, and the 2.5% modulus thereof was measured according to JIS K7161.

6. Measurement of glass adhesion force Glass adhesion force was used to determine the interface adhesion force between the coating material and the glass substrate. The film according to each Example and Comparative Example is cut into a width of 10 mm, and the force when the film is pulled from the surface of the glass substrate at 50 mm / min in the direction of 90 ° and peeled off from the glass substrate is measured as the glass adhesion force. did. The measurement was performed 24 hours after the film was prepared (immediately after the heat aging in the example in which the heat aging was performed for 24 hours).

Table 1 shows the conditions and measurement results of each Example and Comparative Example.

In Examples 1 to 4, acid is generated from the thermoacid generator SI-60L by the heat (greater than 110 ° C.) when ultraviolet rays are irradiated from the electrodeless UV lamp, and the reaction of the silane coupling agent is promoted. It was confirmed that the glass adhesion was improved as compared with the case where the thermoacid generator was not added. Further, in Examples 5 to 6, the heat (60 ° C.) generated by irradiating the LED with ultraviolet rays generates acid from the thermoacid generator SI-60L to promote the reaction of the silane coupling agent, so that the thermoacid generator It was confirmed that the glass adhesion was improved as compared with the case where was not added. In Examples 7 to 9, an acid is generated from the thermoacid generator SI-80L by the heat generated by irradiating ultraviolet rays from the electrodeless UV lamp to promote the reaction of the silane coupling agent, so that the thermoacid generator is added. It was confirmed that the glass adhesion was improved as compared with the case where it was not done. In all of Examples 1 to 9, Young's modulus was maintained at about 1.0 MPa, and the thermoacid generator did not affect the curability of the resin.

On the other hand, in Comparative Example 1 in which the thermal acid generator was not added to the coating material, although a certain degree of glass adhesion was obtained by the action of the silane coupling agent, 24 hours after the preparation of the sample, from each example. It was confirmed that the glass adhesion was small.

Since the thermal acid generator SI-80L used in Example 10 has a decomposition temperature of 80 ° C., acid is unlikely to be generated by the heat (60 ° C.) when ultraviolet rays are irradiated from the LED. However, in Example 10, since heat aging was performed at 80 ° C. for 24 hours after irradiation with ultraviolet rays, sufficient acid was generated from the thermoacid generator to promote the reaction of the silane coupling agent, and the glass adhesion was improved. Was confirmed.

On the other hand, in Comparative Example 2 in which the thermal acid generator SI-80L was used but not heat-aged, it was confirmed that the glass adhesion was small because the acid was not sufficiently generated from the thermal acid generator.

In Example 11 in which the photoacid generator is added in addition to the thermoacid generator, the same or slightly higher glass adhesion as in Example 3 in which only the same amount of the thermoacid generator is added can be obtained. confirmed. On the other hand, in Comparative Example 3 in which the amount of the photoacid generator (5.0 wt%) was larger than the amount of the photopolymerization initiator (3.0 wt%), the Young's modulus was significantly reduced and sufficient curability of the resin was obtained. I couldn't. It is considered that this is because the photoacid generator also inhibits the reaction of the photopolymerization initiator that absorbs ultraviolet rays and generates radical species.

The present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the spirit of the present invention.

10 Coated optical fiber 11 Glass optical fiber 12 Primary layer 13 Secondary layer 14 Coated layer

Claims (5)

The process of drawing a glass optical fiber and
A step of coating the glass optical fiber with a coating material containing an ultraviolet curable resin, a silane coupling agent, and a thermoacid generator that generates an acid by heat.
A step of curing the ultraviolet curable resin by irradiating the glass optical fiber coated with the coating material with ultraviolet rays, and
A step of heating the coating material to a temperature higher than the decomposition temperature of the thermoacid generator, and
Including
When the coating material contains a photoacid generator that generates acid by irradiation with light and a photopolymerization initiator that initiates the polymerization of the ultraviolet curable resin, the amount of the photopolymerizer is the amount of the photopolymerization initiator. A method for producing a coated optical fiber, characterized in that the amount is less than or equal to the amount of The heating step is included in the curing step.
In the curing step, the glass optical fiber coated with the coating material is irradiated with ultraviolet rays to cure the ultraviolet curable resin and generate the acid in the thermal acid generator. The method for manufacturing a coated optical fiber according to claim 1 . The method for producing a coated optical fiber according to claim 1 , wherein the heating step is performed at the same time as the coating step. The method for producing a coated optical fiber according to claim 1 , wherein the heating step is performed after the coating step and before the curing step. The method for producing a coated optical fiber according to claim 1 , wherein the heating step is performed after the curing step.

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