JP2000001630A - Ultraviolet-curable resin composition for coating optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curable resin composition for the coating of optical fiber giving a cured product having low crystallinity even after the storage at a low temperature, small temperature-dependency of Young's modulus and high Young's modulus as well as high elongation. SOLUTION: This resin composition contains (A) a urethane (meth)acrylate oligomer having a number-average molecular weight of >=5,000, (B) a reaction product of a (meth)acrylate having hydroxyl group with a polyisocyanate having a ring structure, (C) an ethylenic unsaturated monomer, (D) a diacrylic monomer of formula (R1, R2 and R3 are each independently an atom or a group selected from hydrogen atom, methyl group and ethyl group) and (E) a photo-polymerization initiator as essential components. The amount of the component B is 25-50 wt.% based on the sum of A to D and the weight ratio of the component A to the component B is <1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber coating having excellent temperature dependency of Young's modulus, providing a cured product having high Young's modulus and high elongation, and having good liquid retention even under low temperature storage. The present invention relates to an ultraviolet curable resin composition.

[0002]

2. Description of the Related Art Characteristics commonly required for a secondary material of optical fiber, a tape material, a hard coat material for a drop wire, and the like are as follows.
The cured product has a high Young's modulus and high elongation, a small temperature dependence of the Young's modulus, and excellent long-term reliability. In the future, since hard coat materials will be used in more severe environments such as drop wire applications, it is increasingly important that the temperature dependence of Young's modulus is further reduced.

Conventionally, as a method of reducing the temperature dependence of the Young's modulus, a high Tg (glass transition temperature, the same applies hereinafter) ethylenic monomer is used to reduce the decrease in the Young's modulus in a high temperature range, Methods of using low molecular weight and high molecular weight urethane acrylates in combination to reduce the change in Young's modulus in a wide temperature range from low to high have been studied.

[0004] However, when an ethylenic monomer having a high Tg is used, the amount of the polyfunctional monomer used is often increased, which causes a problem that the elongation is lowered and the Young's modulus at a low temperature becomes too large. .

When low-molecular-weight and high-molecular-weight urethane acrylates are used in combination, those obtained by reacting a low-molecular-weight diol with a diisocyanate and a hydroxy group-containing acrylate are often used. However, the use of a product obtained by reacting a diisocyanate having a ring structure with a hydroxy group-containing acrylate is more effective for suppressing a decrease in Young's modulus at a high temperature. However, a large amount of a reaction product of a diisocyanate having a ring structure and a hydroxy group-containing acrylate tends to precipitate during storage of a liquid when used in a large amount, which is a problem in quality control. If you reduce its usage,
Since a material with a high Young's modulus cannot be obtained, and a decrease in the Young's modulus at a high temperature is large, a material having a low temperature dependence of the Young's modulus and a high optical fiber protection performance can be obtained as an optical fiber coating hard coat material. Disappears.

The present invention has been made in view of the above circumstances, and provides a cured product having a low Young's modulus temperature dependency, having a high Young's modulus and a high elongation, and having low crystallinity even under low-temperature storage. An object is to provide an ultraviolet-curable resin composition for coating.

[0007]

Means for Solving the Problems and Embodiments of the Invention In order to achieve the above objects, the present invention provides: (A) a urethane (meth) acrylate oligomer having a number average molecular weight of 5,000 or more; (C) Ethylenically unsaturated monomer (D) Diacrylic monomer represented by the following general formula (1) (E) Photopolymerization initiator as an essential component Wherein the component (B) is 25 to 50% by weight of the total amount of the components (A) to (D), and the weight ratio of the component (A) to the component (B) is smaller than 1. An ultraviolet-curable resin composition for coating is provided.

[0008]

Embedded image (In the formula, R ¹ , R ² , and R ³ are each independently an atom or a group selected from a hydrogen atom, a methyl group, and an ethyl group.)

That is, the present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a polyisocyanate having a ring structure such as an aromatic polyisocyanate represented by tolylene diisocyanate and a hydroxyl group-containing polyisocyanate. In a system in which a high molecular weight urethane (meth) acrylate oligomer (A) is used in combination with a low molecular weight urethane (meth) acrylate (B) which is a reaction product with (meth) acrylate, the weight ratio of component (A) to component (B) Lower than 1, and the use of an ethylenically unsaturated monomer (C) compatible with these high and low molecular weight urethane (meth) acrylates (A) and (B) to lower Young's modulus at high temperatures. Is small, it is possible to obtain an ultraviolet-curable resin composition for coating an optical fiber having a small temperature dependence of Young's modulus, It has been found that by adding the diacrylic monomer of the component (D) represented by the formula (1) to this, it is possible to further improve the stability of liquid storage at a low temperature, and the present invention has been achieved. It is.

Hereinafter, the present invention will be described in more detail. Component (A) The component (A) of the ultraviolet-curable resin composition for coating an optical fiber of the present invention is a urethane (meth) acrylate oligomer having a number average molecular weight of 5,000 or more, and generally generally has a number average molecular weight. 5,000 to 50,000, preferably about 5,000 to 15,000.

The component (A) can be obtained by reacting a polyisocyanate with a polyol and a (meth) acrylate having a hydroxyl group.

In this case, the polyisocyanate includes aromatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, aliphatic polyisocyanate and the like. Diisocyanates are widely used as polyisocyanates.

Examples of the aromatic polyisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and 4,4 '
Diisocyanates such as -diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and triphenylmethane-4,4 ', 4 "-triisocyanate , 1,
Tri- or higher polyisocyanates such as 3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, and 4,4′-diphenylmethane-2,2 ′, 5,5′-tetraisocyanate can be mentioned.

The araliphatic polyisocyanate includes
For example, diisocyanates such as 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, 1,3- or 1,4-bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof, 5-
Examples include polyisocyanates such as triisocyanate methylbenzene.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentene diisocyanate and 1,4-cyclopentene diisocyanate.
Cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-
3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane and the like Diisocyanate, 1,3,5-triisocyanatecyclohexane, 1,3,5-trimethylisocyanatecyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) Heptane, 2- (3-isocyanatopropyl) -2,6-di (isocyanatomethyl)
-Bicyclo (2.2.1) heptane, 3- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2 -Isocyanatomethyl-3
-(3-isocyanatopropyl) -bicyclo (2.
2.1) Heptane, 6- (2-isocyanatoethyl)
-2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 5-
(2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3- Tri or higher polyisocyanates such as (isocyanatopropyl) -bicyclo (2.2.1) heptane can be mentioned.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate,
Diisocyanates such as 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate, lysine ester triisocyanate, 1,4,8-
Triisocyanate octane, 1,6,11-triisocyanate undecane, 1,8-diisocyanate-4
-Isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,
Tri- or higher polyisocyanates such as 8-diisocyanate-5-isocyanatemethyloctane can be mentioned.

Furthermore, derivatives from these polyisocyanates can also be used. Derivatives from polyisocyanates include, for example, dimers, trimers, burettes, allophanates, carbodiimides, polymethylene polyphenyl polyisocyanates (also called crude MDI or polymeric MDI), crude TDI, and adducts of isocyanate compounds with low molecular weight polyols And the like.

Among these polyisocyanates, diisocyanates (for example, tolylene diisocyanate, 4,4
An aromatic diisocyanate such as 4'-diphenylmethane diisocyanate, an alicyclic diisocyanate such as isophorone diisocyanate, and an aliphatic diisocyanate such as hexamethylene diisocyanate are often used.

On the other hand, examples of the polyol include polyols such as polyether polyols, polyester polyols, and polycarbonate polyols having a number average molecular weight of about 1,000 to 10,000. Among them, polyether polyols and polycarbonate polyols are preferable, and diols are particularly preferable. Is preferred.

As the polyether polyol, for example, alkylene oxide (eg, ethylene oxide,
Propylene oxide, C ₂ -C _5, such as butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran
Or an alkylene oxide) homopolymer or copolymer, C
_The above alkylene oxide homopolymer or copolymer having a polyol of _{14 to} C ₄₀ (indicating ₁₄ to ₄₀ carbon atoms; the same applies hereinafter) (eg, 12-hydroxystearyl alcohol, hydrogenated dimer diol, etc.) as an initiator. And the above-mentioned alkylene oxide adducts of bisphenol A or hydrogenated bisphenol A. These polyether polyols can be used alone or in combination of two or more. Preferred polyether polyols include C _2-
C ₄ alkylene oxides, especially C ₃ -C ₄ alkylene oxide (propylene oxide, tetrahydrofuran) homopolymer or copolymer, C ₂ -C ₄ alkylene oxide homopolymer and polyol initiator of C ₁₄ -C ₄₀ Or a copolymer is included.

Commercial products can be used as the polyether polyol. As these commercial products, for example,
As polyethylene glycol, "Takelac P-22", "Takelac P-21" by Takeda Pharmaceutical Co., Ltd. as "PEG 1000" and "PEG 2000" manufactured by Sanyo Chemical Industries, Ltd., and as polyoxypropylene glycol,
As Taketake P-23, polytetramethylene ether glycol, "PTG100" manufactured by Hodogaya Chemical Co., Ltd.
0 "," PTG 2000 "," PTG 4000 ",
As a copolymer of tetrahydrofuran and propylene oxide, "PPTG 1000" manufactured by Hodogaya Chemical Co., Ltd.,
“PPTG 2000”, “PPTG 4000”, “Unisafe DCB-1100” and “Unisafe DCB-1800” manufactured by NOF Corporation, and “Unisafe DC-1100” manufactured by NOF Corporation as a copolymer of tetrahydrofuran and ethylene oxide. , "Unisafe DC
-1800 "and the like.

Examples of the polyester polyol include diol components (eg, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentane C ₂ -C ₄₀ aliphatic low molecular weight diols such as diol, 1,6-hexane glycol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 12-hydroxystearyl alcohol, hydrogenated dimer diol and the like An addition reaction product of an alkylene oxide adduct of bisphenol A) and a lactone (eg, ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone); the diol component and a polycarboxylic acid (eg, , Succinic acid, adipic acid Reaction products with aliphatic dicarboxylic acids such as azelaic acid, sebacic acid and dodecane diacid; alicyclic or aromatic dicarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, phthalic acid, isophthalic acid and terephthalic acid) A three-component addition reaction product of the diol component, the dibasic acid component, and a lactone.

Examples of the polycarbonate polyol include the above-mentioned polyether polyol, polyester polyol and diol component (2-methylpropanediol,
Dipropylene glycol, 1,4-butanediol,
1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,5-octanediol, 1,4-bis- (hydroxymethyl) cyclohexane, etc.) and short-chain dialkyl carbonate (for example, Polycarbonate diols obtained by a reaction with C ₁ -C ₄ alkyl carbonates such as dimethyl carbonate and diethyl carbonate.

Furthermore, alkylene oxides (eg, ethylene oxide, propylene oxide, butylene oxide, etc.), lactones (eg, ε-caprolactone, β-methyl-δ)
-Valerolactone) can be used.

As the (meth) acrylate having a hydroxyl group, for example, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate,
4-hydroxybutyl (meth) acrylate, pentanediol mono (meth) acrylate, 2-hydroxy-
3-phenyloxypropyl (meth) acrylate, 2
-Hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate,
Examples thereof include pentaerythritol tri (meth) acrylate and the like, and further include compounds obtained by an addition reaction of a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether and glycidyl (meth) acrylate with (meth) acrylic acid. These (meth) acrylates can be used alone or in combination of two or more. The preferred (meth) acrylate having a hydroxyl group is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or the like.

The urethane (meth) acrylate oligomer of the component (A) can be synthesized by reacting the above components according to a conventional method.

The amount of the component (A) is from (A) to
(D) 20 to 40% of the total amount of the component (% by weight, the same applies hereinafter)
It is preferred that If it is less than 20%, the elongation of the cured product may be lowered or the Young's modulus at room temperature and low temperature may be too large. If it is more than 40%, the composition may have a high viscosity and workability may be reduced. In some cases, a material having a high Young's modulus cannot be obtained.

Component (B) The component (B) of the present invention is a reaction product of a (meth) acrylate having a hydroxyl group and a polyisocyanate having a ring structure. Different from ingredients.

The polyisocyanate having a ring structure used in the synthesis of the component (B) includes, among the polyisocyanates described as the raw materials of the component (A), aromatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates. Any of those having the ring structure exemplified as the polyisocyanate can be used.
Diisocyanates containing an aromatic ring in the molecule, such as aromatic diisocyanates and araliphatic diisocyanates, are preferred, and tolylene diisocyanate is particularly preferred. In this case, as tolylene diisocyanate,
Although there are 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, it is desirable to use 2,4-tolylene diisocyanate having good reactivity of isocyanate groups.

Examples of the (meth) acrylate having a hydroxyl group include the same ones as described in the component (A). For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, 2-hydroxybutyl (meth)
Acrylate, 4-hydroxybutyl (meth) acrylate, pentanediol mono (meth) acrylate, 2
-Hydroxy-3-phenyloxypropyl (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate , Pentaerythritol tri (meta)
Acrylates and the like, and also compounds obtained by an addition reaction of a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether and glycidyl (meth) acrylate with (meth) acrylic acid. These hydroxyl group-containing (meth) acrylates can be used alone or in combination of two or more.
Preferred (meth) acrylates having a hydroxyl group are 2-hydroxyethyl (meth) acrylate,
And hydroxypropyl (meth) acrylate.

Here, when the polyisocyanate and the hydroxyl group-containing (meth) acrylate used in the synthesis of the component (A) are the same as those used in the synthesis of the component (B),
The component (A) and the component (B) may be synthesized at once,
Alternatively, they may be separately synthesized and mixed. On the other hand, when they are not the same, each component can be separately synthesized and mixed.
Furthermore, in the same reaction vessel, first, a prepolymer is synthesized from the isocyanate of the component (A) and the OH component, then the isocyanate of the component (B) is added, and finally, a hydroxyl group-containing (meth) acrylate is reacted to obtain a prepolymer. There is also.

The amount of the component (B) is 25 to 50% of the total amount of the components (A) to (D). If it is less than 25%, a high Young's modulus required for the hard coat material cannot be obtained, and the temperature dependence of the Young's modulus increases. On the other hand, if it is more than 50%,
The Young's modulus becomes too large, resulting in low elongation, poor compatibility with the reactive diluent, and problems such as easy crystallization of the cured composition even at room temperature storage.

The compounding ratio of the components (A) and (B) is such that the weight ratio of the component (A) to the component (B) is 1
It is important to make it smaller, usually in the range of 0.1 to 0.96, preferably 0.5 to 0.95.
If this ratio is greater than 1, the composition becomes high in viscosity and the workability deteriorates, and a high Young's modulus required for the hard coat material cannot be obtained, and the temperature dependence of the Young's modulus increases.

Component (C) The component (C) of the present invention is an ethylenically unsaturated monomer. As the ethylenically unsaturated monomer, urethane (meta) comprising the components (A) and (B) in the composition ) Compatible with acrylate to function as a reactive diluent and at room temperature (1
(About 5 to 30 ° C.), a liquid or solid polymerizable monomer can be used. Ethylenically unsaturated monomers include monofunctional, difunctional and polyfunctional monomers.

Monofunctional monomer (monofunctional polymerizable diluent)
Include, for example, heterocyclic ethylenically unsaturated compounds [for example, N-vinylpyrrolidone, N-vinylpyridine, N-
N-vinyl-nitrogen-containing heterocyclic compounds such as vinylcaprolactam; heterocyclic (meth) acrylates such as morpholine (meth) acrylate and tetrahydrofurfuryl (meth) acrylate; N-vinylformamide;
-Vinylacetamide, dialkylaminoethyl (meth) acrylate [for example, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc.], N, N'-dimethylacrylamide,
Alkoxy (poly) alkylene glycol (meth) acrylate [eg, methoxyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, butoxypolyethylene glycol (meth) acrylate, etc.], alkylphenoxyethyl (meth) acrylate [eg, nonyl Phenoxyethyl (meth) acrylate, etc.), phenoxy (poly) alkylene glycol (meth) acrylate (eg, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, etc.), alkyl (meth) acrylate [eg, butyl (meth) acrylate Acrylate, 2-ethylhexyl (meth) acrylate, etc.], cycloalkyl (meth) acrylate [for example, cyclohexyl Meth) acrylate, etc.], aralkyl (meth) acrylates [e.g., benzyl (meth) acrylate] has a bridged cyclic hydrocarbon group (meth) acrylates [for example, isobornyl (meth) acrylate, dicyclopentadiene (meth)
Acrylate, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyloxyalkyl (meth) acrylate, tricyclodecanyloxyethyl (meth) acrylate,
Isobornyloxyethyl (meth) acrylate, etc.), hydroxyl group-containing (meth) acrylate [for example, 2-hydroxypropyl (meth) acrylate, 3
-Chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth)
Acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, 3-acryloyloxyglycerin mono (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-1
-(Meth) acryloyloxy-3- (meth) acryloyloxypropane, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, etc.), polyε-caprolactone mono (meth) acrylate, glycidyl (meth) acrylate, Mono [2- (meth) acryloyloxyethyl] acid phosphate, halogen-containing (meth) acrylate [for example, trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2, 2,3,4,4,4-hexafluorobutyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, etc.].

Bifunctional monomer (bifunctional polymerizable diluent)
For example, di (meth) acrylate of 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate, (polyoxy) alkylene glycol di (meth) acrylate [eg, ethylene glycol Di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene di (meth) acrylate, 1,4-butane Diol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Pentanediol di (meth) acrylate, etc.], glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, bisphenol A alkylene oxide (ethylene oxide, propylene oxide) adduct (Meth) acrylate [for example, 2,2
Di (meth) acrylate of bis (2-hydroxyethoxyphenyl) propane, etc.), di (meth) acrylate having a bridged cyclic hydrocarbon group [for example, di (meth) acrylate of tricyclodecane dimethylol, dicyclo Pentadiene di (meth) acrylate, etc.), and a (meth) acrylic acid adduct of a bifunctional epoxy resin [for example,
(Meth) acrylic acid adduct of 2,2-bis (glycidyloxyphenyl) propane, etc.].

Polyfunctional monomer (polyfunctional polymerizable diluent)
Examples thereof include trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, tris (acryloyloxy)
Examples include isocyanurate, tris (meth) acrylate of tris (2-hydroxyethyl) isocyanurate, tri (meth) acrylate of tris (hydroxypropyl) isocyanurate, triallyl trimellitic acid, triallyl isocyanurate and the like.

These ethylenically unsaturated monomers can be used alone or in combination of two or more. The amount of the ethylenically unsaturated monomers used is (A) to (E)
It is preferable that the content of the component (D) is 5 to 40%, particularly 10 to 35%.

Among the above-mentioned ethylenically unsaturated monomers, a (meth) acrylate monomer having a bridged cyclic hydrocarbon group such as isobornyl (meth) acrylate and an N-vinylpyrrolidone, N-vinylcaprolactam, etc. -It is desirable to use a vinyl-nitrogen-containing heterocyclic compound and / or a heterocyclic (meth) acrylate monomer such as tetrahydrofurfuryl (meth) acrylate in combination.

That is, a (meth) acrylate having a bridged cyclic hydrocarbon group such as isobornyl acrylate is an acrylic monomer which gives a cured product having a high Tg, and gives the cured product hardness, elongation and flexibility. It has a high effect of reducing the temperature dependence of Young's modulus. Further, it is effective for lowering the water absorption of the cured product, and is effective for improving the long-term reliability maintenance of the optical fiber, such as preventing a decrease in strength due to hydrolysis degradation of the cured product.

The amount of the (meth) acrylate having a bridged cyclic hydrocarbon group is preferably 5 to 20%, more preferably 7 to 15% of the total amount of the components (A) to (D). If the amount is too small, the above-mentioned effects may not be sufficiently exhibited. If the amount is too large, the composition may be easily crystallized.

N-vinyl-nitrogen-containing heterocyclic compounds such as N-vinylpyrrolidone and N-vinylcaprolactam, and heterocyclic (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate have a diluting effect and curability. Urethane (meta) composed of components (A) and (B)
Good compatibility with acrylate, one of these can be used alone or in combination of two or more,
The compounding amount is desirably 5 to 20% of the total amount of the components (A) to (D), and particularly desirably 7 to 15% from the viewpoint of improving curability and reducing the water absorption of the cured product.

Component (D) The component (D) is a diacrylic monomer represented by the following formula (1).

[0044]

Embedded image (In the formula, R ¹ , R ² , and R ³ are each independently an atom or a group selected from a hydrogen atom, a methyl group, and an ethyl group.)

Here, R ¹ and R ² are preferably a methyl group, and R ³ is preferably a methyl group or an ethyl group.

Specific examples of the diacryl monomer as the component (D) include the following.

[0047]

Embedded image

The diacryl monomer of the above formula (1) is Tg
To give a cured product having a high modulus and good compatibility with the urethane (meth) acrylates of the components (A) and (B), so as to reduce the temperature dependence of the Young's modulus and improve the crystallization of the resin composition. And an important component. Of the above-mentioned component (C),
In particular, when used in combination with a (meth) acrylate having a bridged cyclic hydrocarbon group such as isobornyl acrylate, it functions more synergistically to improve these problems.

As the diacrylic monomer of the above formula (1), Kayarad R-604 (manufactured by Nippon Kayaku Co., Ltd.) can be used.

The amount of the component (D) is from (A) to
It is 5 to 30%, preferably 7 to 20% of the total amount of the component (D).

Component (E) The component (E) is a photopolymerization initiator. Examples of the photopolymerization initiator used in the present invention include acylphosphine oxide photopolymerization initiators, acetophenone type, benzoin ether type, benzophenone type, and the like. Photopolymerization initiators such as thioxanthone type are exemplified.

Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (for example, Lucylin TPO manufactured by BASF), bis (2,6-dimethoxybenzoyl) -2, 4,4-trimethylpentylphosphine oxide (BAPO), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2
4,6-trimethylbenzoyl) ethylphosphine oxide, bis (2,4,6-trimethylbenzoyl) n-
Butylphosphine oxide and the like.

Examples of acetophenones include, for example, diethoxyacetophenone, 2-hydroxy-2-methyl-
1-phenylpropan-1-one (for example, Darocure 117 manufactured by Ciba Specialty Chemicals)
3), benzyldimethyl ketal (for example, Irgacure 651, manufactured by Ciba Specialty Chemicals)
BASF, Lucilin BDK, etc.), 1-hydroxycyclohexyl phenyl ketone (eg, Ciba Specialty Chemicals, Irgacure 184),
2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one (for example, Irgacure 907 manufactured by Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butanone (e.g., Ciba Specialty
Chemicals, Irgacure 369), and oligomers of 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone (for example, Esacure KIP, manufactured by Lamberti).

As the benzoin ether type, for example,
Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and the like can be mentioned.

Examples of benzophenones include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 2,4,6-trimethylbenzophenone, and (4-benzoylbenzyl). Trimethylammonium chloride and the like.

As the thioxanthone type, for example, 2-
Or, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and the like.

Other than these, methylphenylglyoxyester (manufactured by AKZO, Vicure 55), 3,6-bis (2-morpholinoisobutyl) -9-butylcarbazole (A-Cure3, manufactured by Asahi Denka Co., Ltd.), titanocene Compounds and the like can also be mentioned.

These photopolymerization initiators can be used in combination, and specific examples thereof include commercially available Irgacure 1700 [bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine. Oxide / 2-hydroxy-2-methylphenylpropan-1-one = 25/75%], Irgacure 1800
[Bis (2,6-dimethoxybenzoyl) -2,4,4
-Trimethylpentylphosphine oxide / 1-hydroxycyclohexyl-phenyl ketone = 25/75%]
(All manufactured by Ciba Specialty Chemicals).

The amount of the photopolymerization initiator (E) to be used is generally 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total of the above components (A) to (D). Part.

The resin composition of the present invention may contain various photopolymerization accelerators, for example, dialkylaminobenzoic acid or a derivative thereof (for example, 4-alkylamine) in order to accelerate a photopolymerization reaction by a photopolymerization initiator, if necessary. Dimethylaminobenzoic acid, 4-
Dimethylaminobenzoic acid ester), a phosphine-based photopolymerization accelerator (arylphosphine such as triphenylphosphine, phosphine-based compound such as trialkylphosphine) and the like may be added. The addition amount of these polymerization accelerators can be in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the components (A) to (D).

A small amount of a stabilizer can be added to the composition of the present invention. As a stabilizer, a hindered phenol-based antioxidant, a hindered amine-based antioxidant, a sulfur-based antioxidant, or the like can be used.

As the hindered phenolic antioxidant, compounds having a hydroxyphenyl group substituted by a t-butyl group, for example, 2,6-di-t-butylhydroxytoluene, 2,2′-methylenebis (4- Methyl-6
-T-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), triethylene glycol-bis [(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1 , 6
-Hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4
-Hydroxy-3,5-di-t-butylanilino)-
1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,
5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-thiobis (4-methyl-6-t-
Butyl) phenol, 4,4'-thiobis (3-methyl-6-t-butyl) phenol, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Hydrocinnamamide), 3,5-di-t-butyl-4-
Hydroxy-benzylphosphonate-diethyl ester and the like.

The hindered amine antioxidants include
For example, bis (2,2,6,6-tetramethylpiperidinyl-4-sebacate), dimethyl-1-succinate (2
-Hydroxyethyl) -4-hydroxy-2,2,6
6-tetramethylpiperidyl polycondensate and the like.

Examples of the sulfur-based antioxidants include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-
3,3′-thiodipropionate, pentaerythritol tetrakis- (β-lauryl-thiopropionate), ditridecyl-3,3′-thiopropionate,
2-mercaptobenzimidazole and the like.

The amount of the stabilizer is 2.0 parts by weight or less based on 100 parts by weight of the total amount of the components (A) to (D).
From the viewpoint of the amount of hydrogen gas generated and the curing speed, 0.1 to 1.
0 parts by weight is preferred.

The resin composition of the present invention may further comprise, if necessary, other than the above components, for example, a stabilizer such as an antioxidant or an ultraviolet absorber other than those described above, a plasticizer, an organic solvent, a silane coupling agent, Various additives such as a water-repellent silane compound, a modified silicone oil, a leveling agent, a surfactant, a coloring pigment, and organic or inorganic fine particles may be added.

The resin composition for coating an optical fiber of the present invention comprises:
Although the high molecular weight urethane (meth) acrylate oligomer (A) is used, the amount of the low molecular weight urethane (meth) acrylate (B) is large, and (A),
Since the reactive diluent (C) compatible with the component (B) is used, 1,000 to 6,000 suitable for high-speed coating properties is used.
It has a low viscosity of cps / 25 ° C.

The composition for coating an optical fiber of the present invention is used as a secondary material of an optical fiber, a tape material, a hard coat material for a drop wire, and the like, and can be applied according to a conventional method. In addition, the curing can be performed by irradiating light, in particular, irradiating ultraviolet rays using an ultraviolet irradiation lamp such as a high-pressure mercury lamp, and the obtained cured product has a high Young's modulus and a high elongation as a hard coat material. 25 ° C Young's modulus 40-120kgf / mm
^2, it has an elongation of 30% or more, has a small temperature dependence of the Young's modulus, is excellent in protecting the optical fiber, and is suitable for obtaining an optical fiber having high reliability.

[0069]

The ultraviolet-curable resin composition for coating an optical fiber of the present invention has a low crystallinity even under low-temperature storage, has a small temperature dependence of Young's modulus, and has a high Young's modulus and high elongation. give.

[0070]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Synthesis Example of Urethane Acrylate] Synthesis Example 56.0 g of hexamethylene diisocyanate, 1,000 g of polytetramethylene ether glycol having a number average molecular weight of 3,000, and 1,000 g of polyoxypropylene ether glycol having a number average molecular weight of 3,000 The mixture is reacted under a nitrogen atmosphere at a temperature of 80 to 90 ° C. for 3 hours, and then the reaction catalyst 1,8-diazabicyclo [5.4.
0] -7-undecene (0.60 g) was further reacted for 4 hours, and it was confirmed by an infrared absorption spectrum that there was no absorption due to isocyanate groups.

In a nitrogen atmosphere, 881.1 g of the urethane polyol (number average molecular weight 6,168) and 497.1 g of 2,4-tolylene diisocyanate were added under nitrogen atmosphere.
The reaction was performed at a temperature of 0 to 80 ° C for 3 hours. Next, after cooling the reaction mixture to 40 ° C., the inside of the reaction vessel was replaced with dry air, and 2-hydroxyethyl acrylate 63
6.0 g and a polymerization inhibitor 0.5 g of 2,6-di-t-butylhydroxytoluene were added, and the temperature was gradually raised.
The reaction was carried out at 70 ° C. for 2 hours. Then, the reaction catalysts 1, 8
-Diazabicyclo [5.4.0] -7-undecene.
56 g was charged and further reacted for 4 hours, and it was confirmed that there was no absorption due to isocyanate groups in an infrared absorption spectrum. Thus, a polyurethane acrylate oligomer A was obtained.

The oligomer A has a number average molecular weight of 6,748.
Was a mixture of 48.0% by weight and a reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate at 52.0% by weight.

Comparative Synthetic Example 1 1295.2 g of urethane polyol (number average molecular weight 6,168) and 348.0 g of 2,4-tolylene diisocyanate obtained in the same manner as in Synthetic Example were mixed in a nitrogen atmosphere for 7 days.
The reaction was performed at a temperature of 0 to 80 ° C for 3 hours. Next, after cooling the reaction mixture to 40 ° C., the inside of the reaction vessel was replaced with dry air, and 2-hydroxyethyl acrylate 41 was removed.
9.4 g and a polymerization inhibitor 0.5 g of 2,6-di-t-butylhydroxytoluene were added, and the temperature was gradually raised.
The reaction was performed at 0 to 70 ° C for 2 hours. Then, the reaction catalyst 1,
0.56 g of 8-diazabicyclo [5.4.0] -7-undecene was charged and reacted for further 4 hours, and it was confirmed that there was no absorption due to isocyanate groups in an infrared absorption spectrum to obtain a polyurethane acrylate oligomer B. .

The oligomer B has a number average molecular weight of 6,748.
Was a mixture of 68.8% by weight and a reactant of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate at 31.2% by weight.

COMPARATIVE SYNTHESIS EXAMPLE 2 A mixture of 500 g of polytetramethylene ether glycol having an average molecular weight of 2,000 and 417.6 g of 2,4-tolylene diisocyanate was placed in a nitrogen atmosphere at 70 to 80 ° C.
At a temperature of 3 hours. Next, after cooling the reaction mixture to 40 ° C., the inside of the reaction vessel was replaced with dry air, and 503.8 g of 2-hydroxyethyl acrylate was added.
0.40 g of a polymerization inhibitor 2,6-di-t-butylhydroxytoluene was added, and the temperature was gradually raised.
For 2 hours. Next, 0.46 g of a reaction catalyst 1,8-diazabicyclo [5.4.0] -7-undecene was charged, and the reaction was further performed for 4 hours. It was confirmed by an infrared absorption spectrum that there was no absorption due to urethane groups, and urethane acrylate oligomer C was obtained.

The oligomer C has a number average molecular weight of 2,580.
Was a mixture of 45.5% by weight and a reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate at 54.5% by weight.

Examples and Comparative Examples A resin composition having the composition shown in Table 1 was prepared, and a cured film was prepared and its physical properties were evaluated by the following methods. Table 1 shows the results. Evaluation method (1) Preparation of sample A resin composition was applied on a glass plate, and 500 mJ / cm ²
(Wavelength: 350 nm) and irradiate with an
A cured film of 50 μm was obtained. (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 tensile speed was 1 mm / min.
The 2.5% tensile modulus was measured under the conditions described above. (3) Measurement of elongation After the cured film was conditioned at 25 ° C. and 50% relative humidity for 24 hours, the distance between the marked lines was 25 mm, and the tensile speed was 500 mm / m.
The tensile elongation at break was measured under the condition of in. (4) The crystalline resin composition is placed in a brown glass bottle, stored at 10 ° C.,
The presence or absence of crystal precipitation was visually observed. ○: No crystal precipitation ×: Crystal precipitation

[0079]

[Table 1]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuhiro Nishimura Inventor, Chemicals Company, Takeda Pharmaceutical Co., Ltd. 2--17-17 Honcho, Yodogawa-ku, Osaka-shi, Osaka (72) Inventor Setsu Uemura Osaka-shi, Osaka 2-17-85, Jusanhoncho, Yodogawa-ku Takeda Pharmaceutical Co., Ltd. Chemical Company (72) Inventor Akira Yamamoto 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture 10 Shin-Etsu Chemical Co., Ltd. In-house (72) Shohei Kosakai 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Masatoshi Asano 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd.

Claims (2)

[Claims] (A) a urethane (meth) acrylate oligomer having a number average molecular weight of 5,000 or more; (B) a reaction product of a (meth) acrylate having a hydroxyl group and a polyisocyanate having a ring structure; (C) ethylene (D) the following general formula (1): (Wherein, R ¹ , R ² , and R ³ are each independently an atom or a group selected from a hydrogen atom, a methyl group, and an ethyl group). Component (B) wherein the component (B) is 25 to 50% by weight of the total amount of the components (A) to (D), and the weight ratio of the component (A) to the component (B) is less than 1. UV curable resin composition for fiber coating. 2. In the total amount of the components (A) to (D), (A)
Component is 20 to 40% by weight, component (B) is 25 to 50% by weight, component (C) is 5 to 40% by weight, and component (D) is 5 to 3%.
The ultraviolet-curable resin composition for coating optical fibers according to claim 1, wherein the amount is 0% by weight.