JPH04161413A - Ultraviolet-setting resin composition for coating optical fiber - Google Patents

Abstract

PURPOSE:To obtain the subject composition capable of forming a coating layer having low water-absorption, excellent alkali resistance and high tensile modulus by compounding a photo-polymerization initiator to a maleimide monomer. CONSTITUTION:The objective composition is produced by compounding (A) a maleimide monomer of formula (R is alkyl, cyclohexyl, etc.) (e.g. N- methylmaleimide) and (B) a photo-polymerization initiator (e.g. benzoyl ethyl ether). The amount of the component B in the composition is preferably 1-5wt.%.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ultraviolet curable resin composition for coating an optical fiber, and more particularly to a secondary coating layer material and tape used for a quartz-based optical fiber. It relates to a material for a covering layer.

[Conventional technology]

It is known that the strength of silica glass constituting optical fibers decreases due to static fatigue in the presence of water. To prevent this, various plastic protective coatings are applied.

In addition, the coating material and coating structure are selected from the viewpoint of transmission loss and handling of the coated optical fiber, in addition to reducing the strength. Generally, optical fibers have a primary coating with a low tensile modulus and a primary coating with a low tensile modulus. Two layers of high modulus secondary coatings are formed as protective coatings. Furthermore, two optical fibers with a primary coating and a secondary coating are bundled together and hardened with plastic (tape structure) to facilitate handling. At present, ultraviolet curable resin compositions are widely used because they have a fast curing speed and enable high-speed drawing of optical fibers.

In the silica glass that makes up the optical fiber, Si-0 bonds are hydrolyzed by alkali [Source: R, J
, Charles, J., Appl, Phys.
, Vol. 29.1554 (1985)), the network structure constituting the glass is destroyed. This destruction of the network structure leads to a decrease in the strength of the glass.

On the other hand, optical fiber cables containing a plurality of coated optical fibers are used in various environments, but the cables are often immersed in water, especially inside conduits or manholes. In order to prevent the strength of optical fibers from decreasing in such environments, gas maintenance systems that flow dry air through the cables and waterproof cables that are filled with waterproof material have been put into practical use.

However, in gas maintenance, due to the high cost of gas pressurization devices, remote monitoring devices, etc., waterproof cables that do not require special monitoring are increasingly being used.

The problem with waterproof cables is that there is no way to detect when tiny pinholes occur in the cable. Therefore, when water enters the cable, it is constructed so that it can be blocked by the waterproof material inside the cable, but it is difficult to completely shield the water and prevent water from moving along the length of the cable. be. Materials known as waterproof materials include:
There is a petroleum-based sherry, but if it is not filled uniformly and in gaps within the cable, water will gradually advance over a long period of time.In this way, it is difficult to completely fill the cable inside the cable during manufacturing. The problem is that it is accompanied by

Another material is a water-absorbing material that absorbs water and creates a dam, but since this basically causes fibers to absorb water, it is difficult to completely shield it.

In this way, waterproof cables have a structure that prevents water from entering to a large extent due to the waterproof material, but it is important to ensure that water does not enter the protective coating of the optical fiber or the surface of the optical fiber over a long period of time (for example, 10 years as the cable life span). It is difficult to guarantee.

Therefore, there are problems in that the coating material deteriorates due to water and the strength of the optical fiber itself decreases.

In addition, water that accumulates in some places in pipes and manholes becomes alkaline due to elution of calcium hydroxide, etc. from concrete.

However, since UV-curable resin compositions used in conventional optical fiber coating materials generally have polar groups such as urethane bonds, ether bonds, ester bonds, and hydroxyl groups in their molecules, they cannot be used in the presence of alkali. There was a problem that it was easily hydrolyzed.

Therefore, optical fibers coated with such conventional ultraviolet curable resin compositions have a problem in that the coating layer deteriorates in an alkaline atmosphere, and as a result, the strength easily decreases. That is, even if the cable is waterproof, the coating deteriorates over a long period of time due to the alkaline water that has entered the cable, and the cable no longer functions to protect the glass. At the same time, the 5i-O bonds of the glass are destroyed by moisture in the presence of alkali on the fiber surface, resulting in a decrease in strength.

Therefore, it essentially had a serious problem in that it could not function as a waterproof cable.

In order to solve these problems, Japanese Patent Publication No. 1-8753
Publication No. 5 (applicant: Nippon Telegraph and Telephone Corporation) discloses an ultraviolet curable resin composition for coating optical fibers with low water absorption.
In the presence of an alkali, it is unlikely to be hydrolyzed over a long period of time (therefore, an optical fiber coated with an ultraviolet curable resin composition with a low water absorption rate has a coating layer that hardly deteriorates in an alkaline atmosphere. , it is stated that the fiber strength can therefore be maintained for a long period of time.

[Problem that the invention seeks to solve]

However, the materials for the secondary coating layer and tape coating layer of conventional ultraviolet curable resin compositions coated on optical fibers have a high water absorption rate and are hydrolyzed in the presence of alkali, causing these materials to deteriorate. The coated optical fiber had a problem in that its strength deteriorated in an alkaline atmosphere. Furthermore, ultraviolet curable resin compositions for coating optical fibers with low water absorption have a problem in that the coating layer thereof has a low tensile modulus and cannot protect the optical fiber.

The problem to be solved by the present invention is to provide an ultraviolet curable resin composition for coating optical fibers that can form a coating layer with low water absorption and high tensile modulus.

[Means to solve the problem]

In order to solve the above problems, the present invention has the following features: 1. (1)
General formula (I) (wherein R is an alkyl group, a cyclohexyl group, a cyclopentyl group, an aryl group, an aryl group substituted with an alkyl group, an aryl group substituted with an alkoxy group, an aryl group substituted with a carboxyl group) or an aryl group substituted with a halogen atom.) An ultraviolet curable resin composition for coating an optical fiber, characterized by containing a maleimide monomer represented by (1) and (2) a photopolymerization initiator. ) A polymerizable unsaturated polyurethane obtained by reacting (a) a hydroxy compound having a polyoxyalkylene block structure, (b) a hydroxy compound having an acryloyl group, and (c) a polyisocyanate, (2)
) A maleimide monomer represented by the above general formula (I), (3) a polymerizable unsaturated compound having two or more acryloyl groups, and (4) a photopolymerization initiator. Curable resin composition and 3. (1) Polymerizable unsaturated polyurethane obtained by reacting (a) a hydroxy compound having a polyoxyalkylene block structure, (b) a hydroxy compound having an acryloyl group, and (C) a polyisocyanate. , (2) a maleimide monomer represented by the above general formula (I), (3) a polymerizable unsaturated compound having one ethylenically unsaturated bond other than the maleimide monomer represented by the above general formula (I) The present invention provides an ultraviolet curable resin composition for coating an optical fiber, which contains (4) a polymerizable unsaturated compound having two or more acryloyl groups and (5) a photopolymerization initiator.

The maleimide monomer represented by the general formula (I) provides a cured product with sufficient tensile elongation at break and tensile break strength, and includes, for example, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-5ee-butylmaleimide, N-te
rt-butylmaleimide, N-pentylmaleimide, N
-Isopentylmaleimide, N-neopentylmaleimide, N-hexylmaleimide, N-hebutylmaleimide, N-octylmaleimide, N-nonylmaleimide, N
-decylmaleimide, N-undecylmaleimide, N-
Dodecylmaleimide, N-cyclopentylmaleimide,
N-cyclohexylmaleimide, N-phenylmaleimide, N-tolylmaleimide, N-xylmaleimide, N
-Trimethylphenylmaleimide, N-ethylphenylmaleimide, N-diethylphenylmaleimide, N-triethylphenylmaleimide, N-chlorophenylmaleimide, N-promophenylmaleinide, N-dichlorofinylmaleimide, N-dibromophenylmaleimide, N- Examples include trichlorophenylmaleimide, N-)dibromophenylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-ethoxyphenylmaleimide, and N-carboxyphenylmaleimide. Commercially available products include, for example,
rPMIJ, rc-PMI manufactured by Daihachi Chemical Industry Co., Ltd.
J, rE-PMIJ, [M-PMIJ, rDM-PMI
J, rcHMIJ, rLMIJ, rHPMrJ and rc
Examples include APMIJ. These 7-reimide monomers can be used alone or in combination of two or more.

Polymerizable unsaturated polyurethane can be easily produced by reacting a hydroxy compound having a polyoxyalkylene block structure, a hydroxy compound having an acryloyl group, and a polyisocyanate.

The polymerizable unsaturated polyurethane can be produced, for example, by the following method.

(2) A method in which a hydroxy compound having an acryloyl group is reacted with a polymer having a functional group obtained by reacting a hydroxy compound having a polyoxyalkylene block structure with a polyisocyanate.

(2) A method in which a hydroxy compound having a polyoxyalkylene block structure is reacted with an adduct having a functional group obtained by reacting a polyisocyanate with a hydroxy compound having an acryloyl group.

■ A famous method in which a hydroxy compound having a polyoxyalkylene block structure, a polyisocyanate, and a hydroxy compound having an acryloyl group are simultaneously reacted.

Examples of the hydroxy compound having a polyoxyalkylene block structure used in methods (1), (2), and (2) above include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, a copolymer of propylene oxide and ethylene oxide, and tetrahydrofuran and propylene oxide. copolymers of tetrahydrofuran and ethylene oxide, ethylene oxide adducts of bisphenol A, and propylene oxide adducts of bisphenol A. Commercially available products include rPEG 600J and rPEG manufactured by Kochu Kasei Co., Ltd. as polyethylene glycol.
G 100OJ and rPEG 2000J; polypropylene glycol manufactured by Mitsui Toatsu Chemical Co., Ltd.
PG diol 1000", rPPGPP-ru 2ooo"
and rPPGPP-R 3000J, “Efsenol 1020J, [Efsenol 2020J and “
Efcenol 3020J; rPTG 650 manufactured by Hodogaya Chemical Co., Ltd. as polytetramethylene glycol
J, r P T G 850J, r P T G
100OJ, rPTG2000J and rPTG 40
00J; rED-28J manufactured by Mitsui Toatsu Chemical Co., Ltd. as a copolymer of propylene oxide and ethylene oxide; and “Efcenol 510J manufactured by Asahi Glass Co.; rP P T manufactured by Hodogaya Chemical Co., Ltd. as a copolymer of tetrahydrofuran and propylene oxide G 100OJ, r
P P T G 2000J and r P P T G
4000J, “Unisafe” manufactured by Nippon Oil & Fats Co., Ltd.
D CB-1100J and [U=SE-7D CB-
1800J; “UNISE-7D C” manufactured by NOF Corporation as a copolymer of tetrahydrofuran and ethylene oxide
-1loOJ and [Unisafe DC-1800J: Uniol DA-400J and "Uniol DA-700J" produced by Nippon Oil & Fats Co., Ltd. as ethylene oxide adducts of bisphenol A;
Examples include B-400J.

These hydroxy compounds having a polyoxyalkylene block structure may be used alone or in combination of two or more.

Examples of the hydroxy compound having an acryloyl group include hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, phenoxyhydroxypropyl acrylate, bovine dihydro-bovine dipropyl acrylate, pentaerythritol acrylate, dipentaerythritol monohydroxypenta Acrylate, trimethylolpropane diacrylate, dipropylene glycol monoacrylate, 1,6-hexanethiol monoacrylate, glycerin diacrylate, caprolactone-modified 2-hydroxyethyl acrylate, stearic acid-modified pentaerythritol diacrylate, polyethylene glycol monoacrylate, polypropylene glycol Monoacrylate, polytetramethylene glycol monoacrylate, monoacrylate of a copolymer of propylene oxide and ethylene oxide, monoacrylate of a copolymer of tetrahydrofuran and propylene oxide, monoacrylate of a copolymer of tetrahydrofuran and ethylene oxide, bisphenol Examples include monoacrylates of ethylene oxide adducts of A and monoacrylates of propylene oxide adducts of bisphenol A.

These hydroxy compounds having an acryloyl group are
It can be used alone or in combination of two or more types.

The ratio of the hydroxy compound having a polyoxyalkylene block structure to the hydroxy compound having an acryloyl group is preferably in the range of 1=9 to 9:1 by weight.

Examples of the polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate,
xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl xylylene diisocyanate,
Trimethylhexamethylene diisocyanate, 1,5-
Examples include naphthalene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, and lysine diisocyanate.

These polyisocyanate compounds can be used alone or in combination of two or more.

The proportion of the polymerizable unsaturated polyurethane used in the ultraviolet curable resin composition of the present invention is preferably in the range of 20 to 80% by weight, particularly preferably in the range of 40 to 70% by weight.

The polymerizable unsaturated compound having one ethylenically unsaturated bond other than the maleimide monomer represented by the general formula (I) gives the cured product sufficient tensile elongation at break and tensile strength, and Can be used in combination with monomers. Examples of such compounds include vinylcaprolactam, N-vinyl-2-pyrrolidone, acryloylmorpholine, vinylimidazole, vinyl-p-
Examples include t-butyl benzoate, cyclohexyl acrylate, inbornyl acrylate, dicyclopentanyl acrylate, and dicyclopentenyl acrylate.

These polymerizable unsaturated compounds having one ethylenically unsaturated bond can be used alone or in combination of two or more.

The proportion of the maleimide monomer and the polymerizable compound having one ethylenically unsaturated bond other than the maleimide monomer in the ultraviolet curable resin composition of the present invention is 5 to 3.
A range of 0% by weight is preferred.

The ratio of the maleimide monomer to the polymerizable compound having one ethylenically unsaturated bond other than the maleimide monomer is preferably in the range of 100:0 to 10:90 by weight.

Examples of the polymerizable unsaturated compound having two or more acryloyl groups include trimethylolpropane triacrylate, ethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1, 6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane trioxyethyl acrylate, tricyclodecane dimetatool diacrylate, dicyclopentadiene diacrylate, tricyclodecanyl diacrylate,
Examples include trimethylolpropane trioxyprobyl acrylate, tris-2-hydroxyethyl isocyanurate triacrylate, and tris-2-hydroxyethyl isocyanurate diacrylate.

These polymerizable unsaturated compounds having two or more acryloyl groups can be used alone or in combination of two or more.

The proportion of the polymerizable unsaturated compound having two or more acryloyl groups in the ultraviolet curable resin composition of the present invention is 20
A range of 80% by weight is preferred, and a range of 30 to 70% by weight is particularly preferred.

The photopolymerization initiator used in the present invention may be one that generates radicals when exposed to light and allows the radicals to react efficiently with the polymerizable unsaturated compound.

There are types in which the molecule cleaves to generate radicals, and types in which the molecules are used in combination, such as a combination of an aromatic ketone and a hydrogen donor. Examples of photopolymerization initiators belonging to the former include benzoylethyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one. , 2. 4.
6-Dolimethylbenzoyldiphenylphosphine, 1-(4-isopropylphenyl)-2-hydrocyto, 2-methylpropan-1-one and 2-methyl-
Examples of photopolymerization initiators belonging to the latter category include 1-(4-(methylthio)phenyl]-2-morpholinopropanone-1, and aromatic ketones such as benzophenone, 4-phenylbenzophenone, and Phthalophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2,4-diethylthioxanthone,
Examples include 2-isopropylthioxanthone and 2-chlorothioxanthone. Examples of the hydrogen donor used in combination with these include mercapto compounds and amine compounds, but amine compounds are generally preferred.

Examples of amine compounds include triethylamine,
Methylgetanolamine, triethanolamine, diethylaminoethyl (meth)acrylate, p-dimethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,
N-dimethylbenzylamine and 4,4'-bis(
diethylamino)benzophenone and the like. These photopolymerization initiators can be used alone or in combination of two or more.

The usage ratio of the photopolymerization initiator in the ultraviolet curable resin composition of the present invention is preferably in the range of 0.1 to 10% by weight, and 1
A range of 5% by weight is particularly preferred.

In addition, as other additives, thermal polymerization inhibitors, antioxidants, plating agents, silane coupling agents, and the like may be added for the purpose of improving various properties.

[Effect]

The second part of the ultraviolet curable resin composition coated on the optical fiber
The material for the next coating layer and the material for the tape coating layer must have toughness, ie, high tensile modulus, sufficient tensile elongation at break, and tensile strength at break, in order to protect the optical fiber. As shown in Experimental Examples 1 and 2 below, the polymerizable unsaturated compound having one ethylenically unsaturated bond provides sufficient tensile elongation at break and tensile break strength to the ultraviolet curable resin composition. It is an essential component for the material for the secondary coating layer and the material for the tape coating layer of the ultraviolet curable resin composition for coating optical fibers. However, conventionally used ultraviolet curable resin compositions containing polymerizable unsaturated compounds having one ethylenically unsaturated bond have high toughness, that is, high tensile elasticity, as shown in Comparative Examples 1 to 3 below. However, it is clear that the alkali resistance is poor due to the large water absorption rate. In addition, ethylenically unsaturated bonds with low water absorption are
As shown in Comparative Examples 4 to 6, the ultraviolet curable resin containing the polymerizable unsaturated compound has a low tensile modulus,
It is clear that optical fibers cannot be protected. - As shown in Examples 1 to 3, the ultraviolet curable resin composition of the present invention containing the maleimide monomer represented by Funazou (I) has high toughness, that is, high tensile modulus, and sufficient tensile rupture. It is clear that the optical fiber coated with the ultraviolet curable resin composition of the present invention has excellent alkali resistance because it has high elongation and tensile breaking strength and low water absorption.

〔Example〕

EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

First, a synthesis example of the polymerizable unsaturated polyurethane of the present invention will be shown.

Synthesis example polytetramethylene glycol (number average molecular weight: 8
50) 1 mole and 2,4-tolylene diincyanate 2
The moles were charged into a reaction vessel equipped with a nitrogen gas inlet tube, a stirrer, and a cooling tube, and the mixture was reacted at 70'C for 2 hours. next,
To this reaction mixture, 2 moles of 2-hydroxyethyl acrylate, a trace amount of t-butylhydroquinone as a polymerization inhibitor, and a trace amount of dibutyltin dilaurate as a catalyst were gradually added, and the reaction was further carried out at 70°C for 5 hours to form a polymerizable polymer. A saturated polyurethane (A) was obtained.

Table 1 shows examples, comparative examples, and experimental examples of the ultraviolet curable resin composition for coating optical fibers of the present invention. These resin compositions were obtained by mixing the respective components of the resin compositions shown in Table 1 in the parts by weight shown in Table 1, and melting the mixture at 60°C for 1 hour. Each of the obtained ultraviolet curable resin compositions was a uniform and transparent liquid. Table 1 shows the physical properties of the ultraviolet curable resin compositions of Experimental Examples 1 and 2, Comparative Examples 1 to 6, and Examples 1 to 4.

For each compound listed in Table 1, the commercially available products listed below were used.

1) Incyanurate triacrylate: manufactured by Toagosei Kagaku Co., Ltd. “Aroex M-325J2) Tris-2-hydroxyethyl isocyanurate triacrylate: manufactured by Hitachi Chemical Co., Ltd. “Fancryl FA?31AJ3)”
Tricyclodecane dimetatool diacrylate: “Yupia UV 5A1002J4” manufactured by Mitsubishi Yuka Co., Ltd.
N-chlorophenylmaleimide: rC-PMIJ manufactured by Ohe Chemical Industry Co., Ltd. 5) N-cyclohexylmaleimide: rCHMIJ manufactured by Ohe Chemical Industry Co., Ltd. 6) N-phenylmaleimide: rPM I J manufactured by Ohe Chemical Industry Co., Ltd. 7) N- Vinyl-2-pyrrolidone.

NV2PJ manufactured by GAF 8) N-vinylimidazole: manufactured by BASF 9) Dicyclopentanyl acrylate: manufactured by Hitachi Chemical ``Fancryl FA513AJlO'' Dicyclopentenyl acrylate: manufactured by Hitachi Chemical ``Fancryl FA511AJ1''
1) Vinyl-p-t-butyl benzoate rVPTBBAJ manufactured by Fuso Chemical Industry Co., Ltd. 12) Benzyl dimethyl ketal rlrgacure 651J manufactured by Cibaken Geigy Co., Ltd. Using each of the ultraviolet curable resin compositions thus obtained, the method described below is carried out. Evaluate the results according to the first
It is described in the physical properties column of the table.

Method for measuring tensile secant elastic modulus Each UV-curable resin composition was applied onto a glass plate so that the dry film thickness was 200 ± 20μ■, and irradiated with ultraviolet rays using a metal halide lamp (lamp output: 2k). A film-like sample was prepared. A No. 2 type test piece was punched out from this film-like sample, and a JIS K7113 test piece was punched out.
The tensile secant modulus was measured according to the following. However, the tensile speed is 4% strain/min, and the tensile secant modulus is 2.5.
Calculated from tensile stress in % strain.

Method for measuring tensile elongation at break and tensile strength at break Measure tensile elongation at break and tensile break strength in accordance with JIS K7113 using a No. 2 test piece prepared by the method described in the section "Method for measuring tensile secant elastic modulus" did. However, the tensile speed was 50 mm/min, and the distance between the gauge lines was 25 mm.

Method for measuring water absorption rate Using a film-like sample prepared by the method described in the section ``Method for measuring tensile secant elastic modulus'', JIS K720 was used.
The water absorption rate was measured according to Method B of Section 9. However, the measurement temperature was 23°C.

〔Effect of the invention〕

The coating layer made of the ultraviolet curable resin composition for coating optical fibers of the present invention has a lower water absorption rate than the coating layer made of the conventional ultraviolet curable resin composition for coating optical fibers.
Excellent alkali resistance.

It also has toughness, that is, high tensile modulus, sufficient tensile elongation at break, and sufficient tensile break strength.

Therefore, the ultraviolet curable resin composition of the present invention is extremely useful as a coating material for fibers that are required to have long-term waterproof properties and toughness.

Agent Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. (1) General formula▲ Numerical formula, chemical formula, table, etc.▼ (In the formula, R is an alkyl group, a cyclohexyl group, a cyclopentyl group, an aryl group, an aryl group substituted with an alkyl group) , which represents an aryl group substituted with an alkoxy group, an aryl group substituted with a carboxyl group, or an aryl group substituted with a halogen atom) and (2) a photopolymerization initiator. Features: Ultraviolet curable resin composition for coating optical fibers. 2. (1) A polymerizable unsaturated polyurethane obtained by reacting (a) a hydroxy compound having a polyoxyalkylene block structure, (b) a hydroxy compound having an acryloyl group, and (c) a polyisocyanate, (2) Claims An ultraviolet curing type for coating optical fibers, comprising a maleimide monomer represented by the general formula described in 1, (3) a polymerizable unsaturated compound having two or more acryloyl groups, and (4) a photopolymerization initiator. Resin composition. 3. Claim 2 further comprising a polymerizable unsaturated compound having one ethylenically unsaturated bond other than the maleimide monomer represented by the general formula of Claim 1.
The ultraviolet curable resin composition for coating an optical fiber as described above.