JP2002131594A - Optical fiber - Google Patents

Abstract

(57) Abstract: In an optical fiber cable in which a primary coating material is applied on a quartz glass fiber and then a secondary coating material is applied on the coating material, the secondary coating material has the following features: Polyurethane (meth) acrylate oligomer having a molecular weight of 20,000 or less 20 to 90% by weight (B) Monoethylenically unsaturated compound having a glass transition temperature of a homopolymer of 50 ° C. or more and containing at least one N-vinyl compound 80 to 10 An optical fiber core, which is a cured product obtained by curing a resin composition containing 5% by weight with an electron beam accelerated at 50 to 125 kV. According to the present invention, it is possible to provide an optical fiber with a small transmission loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber having a primary coating on a quartz glass fiber and a secondary coating on the coating.

[0002]

2. Description of the Related Art Conventionally, various types of optical communication fibers such as quartz, multi-component glass, and plastic have been known.
Above all, silica-based fibers have been widely used because of their light weight, heat resistance, good non-inductive amount, low loss and large transmission capacity.

[0003] Although this silica-based optical communication fiber has the above characteristics, it is extremely thin and brittle, easily breaks due to external factors, and increases transmission loss due to external stress. After a primary coating with a material called a soft primary or buffer coating material, the upper layer is then secondarily coated with a material called a secondary or top coating material to protect the primary coating layer. ing.

The secondary coating layer protects the soft primary coating layer from external force and ultimately improves the strength of the optical fiber. After curing, the secondary coating layer has a high Young's modulus and maintains a high Young's modulus even at a high temperature. In addition, it is required to have characteristics such as high elongation, high strength, low water absorption, and hydrolysis resistance. Furthermore,
In order to improve the productivity, the drawing speed of the optical fiber has been increased, so that it is required to have not only a fast curing property but also a low viscosity.

[0005] As a coating material for the secondary coating,
As disclosed in JP-A-59-170155, a resin composition comprising a urethane oligomer terminated at both ends with an ethylenically unsaturated group as a main component, a polymerizable monomer compound and a photopolymerization initiator is used. Have been. The production of optical fibers from these curable compositions for the secondary coating,
The primary coating composition is coated on the spun silica glass fiber by a coating die, and then irradiated with light by an irradiation device provided with an ultraviolet lamp, cured,
It is performed by coating, similarly applying the secondary coating resin, irradiating ultraviolet rays with an irradiation device, and curing and coating.

[0006] The coating material of these secondary coatings is a light (ultraviolet) curable composition, and although the composition and the secondary coating obtained by these curing systems almost satisfy the characteristics of the cured film, There is a limit in the fast curing property for high-speed drawing.

That is, improvement of curability by this composition and these curing systems is not easy because efficient photopolymerization initiation and development of a high-intensity ultraviolet lamp must be performed. On the other hand, in the same kind of radiation curing, electron beam curing, which polymerizes ethylenically unsaturated groups, does not require a photopolymerization initiator, and it is possible to design a device that can irradiate from a low irradiation dose to a high irradiation dose. Fast curing can be achieved. However, the electron beam accelerated by the high voltage penetrates the coating,
It reaches the silica core glass of the optical fiber, which is an optical transmission line, and damages it, increasing transmission loss.

The present invention has been made in view of the above circumstances, and a cured product having the above-mentioned required characteristics as a secondary coating layer,
It is another object of the present invention to provide an optical fiber core coated with an electron beam-curable secondary coating composition capable of coping with rapid curing and having a small transmission loss.

[0009]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, a conventionally known ultraviolet curable coating composition for optical fibers has been obtained. That is, a resin composition containing (A) a polyurethane (meth) acrylate oligomer and (B) an ethylenically unsaturated compound was coated on a primary coated optical fiber, and accelerated at a low voltage of 50 to 125 kV. The present inventors have found that by coating a cured product cured with an electron beam, it is possible to obtain an optical fiber core wire with high productivity (high-speed drawing) and no increase in transmission loss, and completed the present invention.

That is, according to the present invention, in a fiber coated optical fiber in which a primary coating material is applied on a quartz glass fiber, and then a secondary coating material is applied on the coating material, the secondary coating material comprises: (A) a number average molecular weight Polyurethane (meth) acrylate oligomer of 20,000 or less 20-90% by weight (B) Monoethylenically unsaturated containing at least one N-vinyl compound having a glass transition temperature (Tg) of 50 ° C. or more of the homopolymer. An optical fiber core is provided, which is a cured product obtained by curing a resin composition containing a compound at 80 to 10% by weight with an electron beam accelerated at 50 to 125 kV.

Hereinafter, the present invention will be described in more detail.
The optical fiber core wire of the present invention is obtained by coating a primary layer with a primary coating material on a quartz glass fiber, and further coating a secondary layer with a secondary coating material on this.

Here, as the coating composition for forming the primary layer, any known coating composition for a primary layer can be used, and the curing method may be an ultraviolet curing type, an electron beam curing type, or the like. Any one may be used.

[0013] In the present invention, the secondary layer formed on the primary layer may have a (A) polyurethane (meth) acrylate oligomer having a number average molecular weight of 20,000 or less, (B) a homopolymer having a glass transition temperature (Tg) of 50 ° C. As described above, a resin composition containing a monoethylenically unsaturated compound containing at least one kind of N-vinyl compound is formed. Hereinafter, this resin composition will be described in detail.

(A): Number average molecular weight of 20,000 or less
Polyurethane (meth) acrylate oligomer The polyurethane (meth) acrylate oligomer which is the first component of the resin composition of the present invention comprises (a) a polyol,
It can be obtained by a urethanization reaction of (b) a polyisocyanate and (c) a (meth) acrylate compound having a hydroxyl group. The number average molecular weight of the polyurethane (meth) acrylate oligomer can be selected, for example, from the range of 20,000 or less, preferably 10,000 or less.

(A) Polyol component As the polyol component, polyether polyol, polyester polyol, polycarbonate polyol,
And alkyl diols. The (polyether polyol) polyether polyols, such as alkylene oxides (e.g. ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, C _{2 ~ 5} alkylene oxide, such as 3-methyltetrahydrofuran) homopolymer or copolymer of fat group C _{12 ~ 40} polyols (such as 1,2-hydroxy stearyl alcohol, hydrogenated dimer diol, etc.) the alkylene oxide homopolymer or copolymer was the initiator, alkylene oxides of bisphenol a (such as propylene oxide, butylene oxide , Tetrahydrofuran) and alkylene oxide (eg, propylene oxide, butylene oxide, tetrahydrofuran) adducts of hydrogenated bisphenol A. These polyether polyols can be used alone or in combination of two or more.

Preferred polyether polyols are C _2
1-4 alkylene oxide, a homo- or copolymer of a particular C _{3 - 4} alkylene oxide (propylene oxide and tetrahydrofuran) (polyoxypropylene glycol, polytetramethylene ether glycol, a copolymer of propylene oxide and tetrahydrofuran) and the like.
In particular, it is preferable to use a polyether polyol having an oxypropylene structure or a polypropylene glycol in combination in order to reduce the viscosity of a resin or to generate a low hydrogen gas in a cured product for high-speed tape formation. The number average molecular weight of the polyether polyol is, for example, 200 to
It can be selected from a range of about 10,000.

These commercially available products include, for example, (1)
As polyethylene glycol, “PEG600”, “PEG1000”, “PEG20” manufactured by Sanyo Chemical Industries, Ltd.
00, (2) Taketake Pharmaceutical Company Limited “Takelac P-21”, “Takelac P-22”, “Takelac P-23” as polyoxypropylene glycol, (3)
As polytetramethylene ether glycol, "PTG650", "PTG850", "P
TG1000 ”,“ PTG2000 ”,“ PTG400 ”
0 ”, (4)“ ED-2 ”manufactured by Mitsui Toatsu Chemicals, Inc. as a copolymer of propylene oxide and ethylene oxide.
8), “Exenol 510” manufactured by Asahi Glass Co., Ltd., and (5) “PPTG1000”, “PP” manufactured by Hodogaya Chemical Co., Ltd. as a copolymer of tetrahydrofuran and propylene oxide.
TG2000 "," PPTG4000 ", (6) as a copolymer of tetrahydrofuran and ethylene oxide,
"Unisafe DC-1100" and "Unisafe DC-1800" manufactured by NOF Corporation, and (7) "UNIOL DA-400" and "UNIOL DA-70" manufactured by NOF Corporation as adducts of ethylene oxide of bisphenol A.
0 "and (8)" UNIOL DB-4 "manufactured by NOF Corporation as an adduct of bisphenol A with propylene oxide.
00 ”and the like.

(Polyester polyol) Examples of the polyester polyol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,5-pentaglycol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. An adduct of a diol compound such as neopentyl glycol and ε-caprolactam or β-methyl-δ-valerolactone; and a diol compound such as succinic acid, adipic acid, phthalic acid, hexahydrophthalic acid or tetrahydrophthalic acid. Reaction products with basic acids; three-component reaction products of the above-mentioned diol compounds with the above-mentioned dibasic acids and ε-caprolactam or β-methyl-δ-valerolactone.

(Polycarbonate polyol) Examples of the polycarbonate polyol include 1,6-hexanediol, 3-methyl-1,5-pentanediol,
Neopentyl glycol, 1,4-butanediol,
1,5-octanediol, 1,4-bis- (hydroxymethyl) cyclohexane, 2-methylpropanediol, dipropylene glycol, dibutylene glycol,
Examples thereof include polycarbonate polyols composed of a diol compound such as bisphenol A, or a reaction product of a diol compound and a short-chain dialkyl carbonate such as an ethylene oxide 2 to 6 mol addition reaction product, dimethyl carbonate, or diethyl carbonate.

Furthermore, polyester diols which are ethylene oxide, propylene oxide, ε-caprolactam or β-methyl-δ-valerolactone addition products of these polycarbonate polyols can also be used.

Commercially available polycarbonate polyols include "Desmophen 2020" manufactured by Sumitomo Bayer.
E "," DN-980 "," D
N-982 "and" DN-983].

(Alkyl diol) Examples of the alkyl diol include 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4-butanediol, 1,5-octanediol, 1,4-dihydroxycyclohexane, 1,4-bis- (hydroxymethyl) cyclohexane, 2-methylpropanediol, tricyclodecanedimethanol,
Examples thereof include 1,4-bis- (hydroxymethyl) benzene and bisphenol A.

Among these polyols, polyether polyols and alkyl diols are preferable from the viewpoint of balance of physical properties and durability of the resin composition of the present invention.

(B) Polyisocyanate As the polyisocyanate component, for example, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene Diisocyanate,
Isophorone diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, transcyclohexane-1,
4-diisocyanate, lysine diisocyanate, tetramethylxylene diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, Bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate and the like are used. Among these, a polyisocyanate having a cyclic structure is particularly preferable because a cured product having a high Young's modulus can be obtained.

(C) A (meth) acrylate having a hydroxyl group
The (meth) acrylate having a preparative hydroxyl group include hydroxyalkyl (meth) acrylates [such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth)
Acrylate, pentanediol mono (meth) acrylate, hexanediol mono (meth) acrylate, hydroxy C _{2 ~ 10} alkyl (meth) acrylates such as neopentyl glycol mono (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (Meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, cyclohexane 1,
4-dimethanol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate and the like, and further compounds containing glycidyl or epoxy groups [eg alkyl glycidyl ether, allyl glycidyl ether,
Such as glycidyl (meth) acrylate] and (meth) acrylic acid. These hydroxyl group-containing (meth) acrylates can be used alone or in combination of two or more. Preferred hydroxyl group-containing (meth) acrylates, hydroxy C _{2 ~ 4} alkyl (meth) acrylates, in particular 2-hydroxyethyl (meth) acrylate, and the like 2-hydroxypropyl (meth) acrylate.

The polyurethane (meth) acrylate oligomer can be prepared by reacting the above-mentioned components. The ratio of each component constituting the polyurethane (meth) acrylate oligomer is, for example, 1 mole of isocyanate group of polyisocyanate. On the other hand, the hydroxyl group of the polyol component is 0.1 to 0.8 mol, preferably 0.2 to 0.8 mol.
0.7 mol, especially about 0.2 to 0.5 mol, hydroxyl group-containing (meth) acrylate 0.2 to 0.9 mol, preferably 0.3 to 0.8 mol, particularly 0.5 to 0.8 mol It is about a mole.

The method of reacting the above components is not particularly limited, and the components may be mixed and reacted together. The polyisocyanate, the polyol component and the hydroxyl group-containing (meth)
After reacting with any one component of the acrylate, the other component may be reacted.

Examples of the catalyst for the urethanization reaction include stanna octoate, dibutyltin diacetate, dibutyltin dilaurate, cobalt naphthenate, and the like.
Organometallic urethanization catalysts such as lead naphthenate and, for example, triethylamine, triethylenediamine, amine catalysts such as diazabicycloundecene can be used,
Other known urethanization catalysts can also be used.

(B) A homopolymer having a Tg of 50 ° C. or higher
No ethylenically unsaturated compound The homopolymer of component (B) used in the present invention has a Tg of 5
Examples of the monoethylenically unsaturated compound at 0 ° C. or higher include N-vinylacetamide compounds and compounds having a structure in which (meth) acrylic acid is bonded to a compound containing an amino group or a hydroxyl group by an amidation reaction or an esterification reaction. No.

Examples of the N-vinylacetamide compounds include N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-vinylformamide and the like. Compounds containing an amino group or a hydroxyl group include (meth) acrylic acid Are bonded by an amidation reaction or an esterification reaction as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentadiene (meth) acrylate , 2-hydroxyethyl (meth)
Acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate,
Examples include tricyclodecanyl (meth) acrylate, tricyclodecanyloxy (meth) acrylate, morpholine (meth) acrylate, vinylpyridine, vinylimidazole, and the like.

Among these compounds, N-vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, It is preferable to include any of N-vinylacetamide and N-vinylformamide.

The amounts of the polyurethane (meth) acrylate oligomer and the monoethylenically unsaturated compound are determined according to the types of the polyurethane (meth) acrylate oligomer (A) and the monoethylenically unsaturated compound (B). The polyurethane (meth) acrylate oligomer of the component (A) is selected based on the desired viscosity of the composition or the physical properties of the cured product thereof, and the total weight of the component (A) and the component (B) is 20%. ９０90% by weight, preferably 40-80% by weight. (B)
The component monoethylenically unsaturated compound is 80 to 10% by weight.
And preferably 60 to 20% by weight. Furthermore,
(B) 3 to 20% by weight of an N-vinyl compound as a component,
Preferably, the content is 5 to 15% by weight.

Further, a compound having a plurality of ethylenically unsaturated groups in the molecule may be blended. These compounds are, as bifunctional compounds, specifically, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3.
-Hydroxypropionate di (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) ) Acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycol di (meth) acrylate, neopentyl glycerin di (meth) acrylate, neopentyl glycol dihydroxypivalate (Meth) acrylate, di (meth) acrylate of ethylene oxide adduct of bisphenol A, di (meth) acrylate of propylene oxide adduct of bisphenol A, 2,2′- Di (hydroxyethoxyphenyl) propane di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, dicyclopentadiene di (meth) acrylate, pentanedi (meth) acrylate, 2,27-di (glycidyloxyphenyl) A) propane di (meth) acrylic acid adduct;

Examples of the polyfunctional compound include trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, tris (acryloxy) isocyanurate, tris (2-hydroxy) isocyanurate , Tris (hydroxypropyl) isocyanurate tri (meth) acrylate,
Tri (meth) acrylate of isocyanurate, triallyl trimellitic acid, triallyl isocyanurate and the like can be mentioned. The amounts of these components are not particularly limited as long as the characteristics of the secondary coating material of the present invention are satisfied.

Further, if necessary, a polymerization initiator may be added. Known polymerization initiators can be used, for example, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,2-dimethoxy-2-phenylacetophenone, phenylacetophenone diethyl ketal, alkoxyacetophenone, benzyl methyl ketal Benzophenone derivatives such as benzophenone, 3,3-dimethyl-4-methoxybenzophenone, 4,4-dimethoxybenzophenone and 4,4-diaminobenzophenone; alkyl benzoylbenzoate;
Dialkylaminophenyl) ketone, benzyl derivatives such as benzyl and benzylmethyl ketal, benzoin derivatives such as benzoyl and benzoin butyl methyl ketal, benzoin isopropyl ether, 2-hydroxy-2-methylpropiophenone, 2,4-diethylthioxanthone and Thioxanthone derivatives such as 1,4-dichlorothioxanthone, fluorene, 2-methyl-1-
[4- (Methylthio) phenyl] -2-morpholinopropane-1,2-benzyl-2-dimethylamino-1-
(Morpholinophenyl) -butanone-1,2,4,6-
Trimethylbenzoyldiphenylphosphine oxide,
Bis (2,6-dimethoxybenzoyl) -2,4,4-
Phosphine oxide derivatives such as trimethylpentyl phosphine oxide, benzoyl peroxide, t-butyl peroxide, organic peroxides such as cumene hydroperoxide, azobiscyanovaleric acid, azobisbutyronitrile,
Organic azo compounds such as azobis (2,4-dimethyl) valeronitrile and azobis (2-aminopropane) hydrochloride are exemplified.

These may be used alone or in combination of two or more. The compounding amount is not particularly limited as long as the characteristics of the secondary coating material of the present invention are similarly satisfied.

These resin compositions may contain, in addition to the above components, stabilizers such as antioxidants and ultraviolet absorbers, organic solvents, plasticizers, surfactants, silane coupling agents, coloring pigments, organic or inorganic Additives such as particles can be added as needed within a range that does not impair the purpose of the present invention.

The viscosity of the resin composition of the present invention is usually from 1,000 to 10,000 mPa · s (25
° C), especially at high production speeds of 1,000 to 4,000.
The range of mPa · s (25 ° C.) is desirable. Further, this composition is cured by irradiation with an electron beam in the same manner as in the case of a usual ultraviolet-curable composition, and becomes a cured product. Desirable to protect the core from external forces as a jacket 300
It is desirable to have a Young's modulus of ~ 900 MPa.

The optical fiber core wire of the present invention is obtained by coating the above resin composition on an optical fiber coated with a primary coating, and then coating the cured product cured with an electron beam accelerated at a low voltage of 50 to 125 kV. Is obtained by At present, the structure of a quartz optical fiber cable for communication which is mass-produced has a quartz core of about 10 μm in diameter, and a quartz clad on the outer periphery of which has a diameter of about 200 μm on the outer periphery of a glass fiber having a thickness of about 125 μm. The primary coating material is coated with such a thickness, and finally the upper coating layer is coated with a secondary coating material having a thickness of about 250 μm. In such a fiber structure, if the accelerating voltage of the electron beam for curing the secondary coating resin composition exceeds 125 kV, the electron beam reaches the core and causes damage, thereby increasing transmission loss. If the voltage is less than 50 kV, the electron beam cannot reach the bottom of the secondary coating layer, and an uncured secondary coating layer may be obtained. Therefore, the accelerating voltage of the electron beam is 5
It is 0 to 125 kV, preferably 60 to 100 kV. Also, the absorbed dose given to the secondary coating resin composition,
It depends on the type of the resin composition and is not particularly limited, but is in the range of 10 to 100 kGy.

[0040]

According to the present invention, it is possible to provide an optical fiber having a small transmission loss.

[0041]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(A) Polyurethane acrylate oligomer
Synthesis of chromatography [Synthesis Example 1] 2,4-toluene diisocyanate 31
A mixture of 9.6 g and 502.5 g of polytetramethylene ether glycol having an average molecular weight of 1,000 was reacted at a temperature of 70 to 80 ° C. for 3 hours under a nitrogen atmosphere. Next, the reaction mixture was cooled to 30 ° C., the inside of the reaction vessel was replaced with dry air, and the polymerization inhibitor 2,6-di-tert- was added.
0.4 g of butylhydroxytoluene was added, and 310.1 g of 2-hydroxyethyl acrylate was added to the reaction mixture.
The solution was dropped so as to be 0 ° C. or less. Then, the temperature was gradually raised, and the reaction was carried out at a temperature of 60 to 70 ° C. for 6 hours. It was confirmed by an infrared absorption spectrum that there was no absorption due to the isocyanate group (NCO), and polyurethane acrylate oligomer I was obtained.

Synthesis Example 2 14.04 g of hexamethylene diisocyanate, polyoxypropylene ether glycol having an average molecular weight of about 3,000 (OH value = 34 mgK
OH / g) 385.5 g, polytetramethylene ether glycol (OH value = 37.5 mg KOH / g) 14
A mixture of 9.5 g and a reaction catalyst, 0.5 g of dibutyltin dilaurate, was reacted under a nitrogen atmosphere at a temperature of 70 to 80 ° C. for 4 hours, and an isocyanate group (N
It was confirmed that there was no absorption due to CO). Then, the reaction mixture was cooled to 30 ° C., and 369.3 g of 2,4-toluene diisocyanate was added.
The reaction was performed at 0 ° C. for 2 hours. The reaction mixture was cooled to 30 ° C., the inside of the reaction vessel was replaced with dry air, and the polymerization inhibitor 2,6-di-tert-butylhydroxytoluene was added to 0.1 ml.
44 g of 2-hydroxyethyl acrylate 47
2.4 g was added dropwise so that the temperature of the reaction mixture became 50 ° C. or lower. Next, the reaction catalyst dibutyltin dilaurate 0.9 g
Was added, and the temperature was gradually raised, and the mixture was reacted at a temperature of 60 to 70 ° C. for 6 hours, and an isocyanate group (N
It was confirmed that there was no absorption due to CO), and polyurethane acrylate oligomer II was obtained.

Examples 1 to 4 and Comparative Examples 1 to 6 As shown in Table 1, the polyurethane acrylate oligomers I and II synthesized above and a compound containing an ethylenically unsaturated group were mixed. To 4, and the electron beam-curable resin compositions of Comparative Examples 1 to 6 were prepared. Next, physical properties of the obtained composition were measured as shown below. Further, the composition of Example 3 was applied to a quartz fiber coated with the primary coating composition, cured by an electron beam irradiation device, and the transmission loss of the obtained optical fiber core was measured by the method described below. Table 1 shows the results.

Evaluation method: (1) Preparation of cured film The above electron beam-curable resin composition was coated on a glass plate by 50 to 60.
An electron beam applied to a thickness of μm and accelerated at 30 to 100 kV was irradiated under nitrogen to an absorbed dose of 100 kGy to obtain a cured film. (2) Measurement of Young's Modulus After conditioning the cured film at 25 ° C. and 50% relative humidity for 24 hours, the distance between the marked lines was 25 mm, and the pulling speed was 1 mm / m.
The 2.5% tensile modulus was measured under the conditions of "in". (3) Measurement of tensile strength and elongation at break After conditioning the cured film at 25 ° C. and 50% relative humidity for 24 hours, the distance between the marked lines was 25 mm, and the tensile speed was 50 mm /
It was measured under the condition of min. (4) Curable The above-mentioned electron beam-curable resin composition is coated on a glass plate by 50 to 60.
An electron beam applied to a thickness of μm and accelerated at 100 kV was cured under irradiation conditions such that the absorbed dose was 20, 30, 100 kGy under nitrogen, and the Young's modulus of the cured film was measured. (5) Measurement of Young's modulus ratio, glass transition temperature After conditioning the cured film at 25 ° C. and 50% relative humidity for 24 hours, a device for measuring viscoelastic behavior [Rheome]
tricks Solids AnalyzerRSAI
The Young's modulus at −40 ° C. and 25 ° C. was measured using I (manufactured by Rheometrics Scientific F. Ltd.), and the Young's modulus ratio was calculated. (6) Preparation of Optical Fiber and Measurement of Transmission Loss The following primary coating composition was applied onto a spun quartz glass fiber so as to have a diameter of 200 μm. , Cured with an ultraviolet irradiation device, and then 250 μm in diameter,
The resin composition of Example 3 in Table 1 was applied, and irradiated with an electron beam accelerated at three different voltages simultaneously in three directions by an electron beam irradiation apparatus so as to have an absorbed dose of 100 kGy, and cured.
An optical fiber of 100 m was obtained. Using OTDR, the transmission loss of the light having a wavelength of 1,550 nm of the obtained optical fiber was measured. Primary coating composition 407.3 g of polypropylene glycol having a number average molecular weight of about 4,000 (Sanix PP, manufactured by Sanyo Chemical Industry Co., Ltd.)
4000, OH group = 27.6) and 52.2 g of 2,4-tolylene diisocyanate were charged into a reaction vessel and reacted at 70 to 80 ° C. for 2 hours under a stream of nitrogen. Thereafter, the reaction temperature was lowered to 50 to 60 ° C., 0.6 g of dibutyltin dilaurate, 0.15 g of 2,6-di-tert-butylhydroxytoluene, and 23.2-hydroxyacrylate.
2 g was added and reacted for 5 hours, and the number average molecular weight was about 8.9.
00 polyether polyurethane acrylate oligomer was obtained. 60 parts by weight of this oligomer, Aronix M
-113 (manufactured by Toa Gosei Co., Ltd.), 10 parts by weight of lauryl acrylate, 10 parts by weight of N-vinylcaprolactam, and 3 parts by weight of Irgacure 1700 (manufactured by Ciba Specialty Chemicals) were mixed to prepare a primary coating composition. Obtained.

[0046]

[Table 1] * Glass transition temperature of homopolymer

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[Procedure amendment]

[Submission date] November 1, 2000 (200.11.
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction contents]

[0046]

[Table 1] * Glass transition temperature of homopolymer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Konishi 2-3-1-1, Isobe, Annaka-shi, Gunma Prefecture Shin-Etsu Chemical Industry Co., Ltd. Precision Materials Research Laboratory (72) Inventor Toshio Ohba Isobe, Annaka-shi, Gunma 2-13-1 Shin-Etsu Kagaku Kogyo Co., Ltd. Precision Functional Materials Laboratory F-term (Reference) 2H050 BA17 BA32 BB03S BB07S BB09S BB14S BB17S BB34S BC03 BD00 BD03 4J011 QA03 QA12 QA13 QA23 QA24 QA25 QA26 QA27 QA34 QA34 SA22 SA24 SA25 SA26 SA34 SA42 SA51 SA64 SA76 SA79 SA84 UA03 VA01 WA03 4J027 AC03 AC04 AC06 AG02 AG03 AG04 AG09 AG12 AG14 AG23 AG24 AG27 AG28 AJ08 BA07 BA13 BA15 BA17 BA19 BA20 BA21 BA24 BA26 BA28 BA29 CB00 CB03 CB09 CC03 CD03

Claims (2)

[Claims] An optical fiber having a primary coating material on a quartz glass fiber and a secondary coating material on the coating material, wherein the secondary coating material comprises: (A) a number average molecular weight of 20,000 or less. (B) a homopolymer having a glass transition temperature of 50 ° C. or more and a monoethylenically unsaturated compound containing at least one N-vinyl compound in an amount of 80 to 10% by weight; An optical fiber core, which is a cured product obtained by curing a resin composition contained therein with an electron beam accelerated at 50 to 125 kV. 2. The optical fiber cable according to claim 1, wherein the N-vinyl compound is selected from N-vinylpyrrolidone, N-vinylcaprolactam, and N-vinylformamide.