JP2002145970A - Liquid radiation curing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid radiation curing resin composition having good curability with a small radiation exposed dose and a low water absorption coefficient. SOLUTION: This liquid radiation curing resin composition is characterized as comprising (A) 100 pts.wt. of a polyether polyurethane having at least two (meth)acrylic groups in one molecule and 800-10,000 number-average molecular weight and (B) 1-100 pts.wt. of a compound having a vinyl ether group in the molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid radiation-curable resin composition having excellent high-speed coating properties, and more particularly to a primary coating material, a secondary coating material, and an optical fiber used as a coating material for an optical fiber. The present invention relates to a liquid radiation-curable resin composition suitable as a coating material such as a tape material.

[0002]

2. Description of the Related Art There are various types of optical communication fibers such as silica glass, multi-component glass, and plastic, but in reality, their light weight, low loss, Due to its high durability and large transmission capacity, quartz glass-based materials are widely used in a wide range of fields. However, since the silica glass-based fiber is extremely thin and changes may occur due to external factors, the silica glass-based optical communication fiber is a soft liquid curable material that is previously cured on a fused-spun silica glass fiber. After coating and curing with a resin and performing a primary coating, a secondary coating is further applied with a hard liquid curable resin of a cured product in order to protect the primary coating layer. This is called an optical fiber core wire. Further, several (usually four or eight) core wires are bundled, and a tape material is applied and hardened.
Tape cores are manufactured.

As these coating materials, urethane acrylate-based ultraviolet curable resin compositions have been proposed, and are disclosed in Japanese Patent Publication No. 1-16944 and Japanese Patent No. 2522.
As described in U.S. Pat. No. 663 and Japanese Patent No. 2547021, an ultraviolet liquid curable composition comprising a urethane acrylate oligomer, a reactive diluent and a photopolymerization initiator is known. However, in recent years, the drawing speed of the optical fiber has been increased in order to improve productivity, and a resin having good curability with a small amount of irradiation of ultraviolet rays is required. From the viewpoint of increasing the curing rate, JP-A-10-204250 describes a resin composition containing a compound containing a (meth) acryloyl group and a compound containing an N-vinyl group. When a compound containing the fiber is contained, the water absorption rate is increased, and there is a problem that the reliability over time after laying the fiber is poor. As another solution, there is a method of increasing the number of ultraviolet lamps to be irradiated at the time of drawing an optical fiber to increase the amount of ultraviolet irradiation, but there is a problem that curing in a limited space is limited.

The present invention has been made in view of the above circumstances, and has excellent curability and excellent properties of a cured film to be obtained.
In particular, it is an object of the present invention to provide a liquid radiation-curable resin composition having a small water absorption of a cured film.

[0005]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that a liquid radiation curable resin composition has a (meth) acrylic group. By adding a compound containing a vinyl ether group in the molecule (hereinafter referred to as a vinyl ether compound) to a polyether polyurethane containing a, a cured film having good curability with a small radiation dose and a small water absorption is provided. Was obtained. In general, it is known that vinyl ether compounds generate an acid upon irradiation with an onium salt or the like and undergo cationic photopolymerization, and are often used as a mixture with a plurality of vinyl ether compounds or epoxy compounds. But (meta)
There are few reports on its use as a radical polymerization with acrylic compounds, and in particular, little is known about the behavior upon irradiation with ionizing radiation such as an electron beam.

[0006] The present inventors have found that even if a polymerization initiator is not present, a mixed system of a vinyl ether compound and a polyether polyurethane containing a (meth) acryl group is cured by irradiation with an electron beam, and a radical photopolymerization initiator is obtained. It was found that the composition was cured by irradiation with ultraviolet light in the presence of, and the present invention was accomplished.

Accordingly, the present invention provides: (A) 100 parts by weight of a polyether polyurethane having a number average molecular weight of 800 to 10,000 having at least two (meth) acryl groups in one molecule; Compounds having a group
A liquid radiation-curable resin composition characterized by containing 100 parts by weight.

In the present invention, in addition to the above components (A) and (B), (C) a reactive diluent having a molecular weight of 500 or less and having a (meth) acrylic group and / or an N-vinyl group is added in an amount of 1 to 200% by weight. The present invention provides a liquid radiation-curable resin composition characterized by containing:

Further, in the present invention, the above (A), (B),
In addition to the component (C), a photo-radical polymerization initiator and / or a photo-cationic polymerization initiator may be used as (A) + (B) + (C) = 100
Provided is a liquid radiation-curable resin composition which is contained in an amount of 0.01 to 20 parts by weight based on parts by weight.

Hereinafter, the present invention will be described in more detail.
The liquid radiation-curable resin composition of the present invention comprises (A) a polyether polyurethane having a number average molecular weight of 800 to 10,000 having at least two (meth) acryl groups in one molecule, and (B) a vinyl ether in the molecule. Including compounds having a group.

The polyether polyurethane having at least two (meth) acryl groups in one molecule, which is the component (A) of the present invention, has a number average molecular weight of 800 to 10,000,
Preferably it is 1,000-8,000. When the number average molecular weight is less than 800, the obtained cured film has a small elongation and is easily peeled off at the time of coating.
If it is more than 000, the hardness and Young's modulus of the cured film become small, and the cured film is easily damaged and does not function as a protective film.

The polyether polyurethane having at least two (meth) acryl groups in one molecule of the present invention is
For example, it can be obtained by reacting a diol having an oxyalkylene group having 2 to 10 carbon atoms with a compound having a diisocyanate and a (meth) acryl group.

Here, specific examples of the diol containing an oxyalkylene group having 2 to 10 carbon atoms include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 2-methyltetrahydrofuran glycol, 3-methyltetrahydrofuran glycol, and polyheptamethylene. Glycol, polyhexamethylene glycol, polydecamethylene glycol, bisphenol A
And the like, and polypropylene glycol, polytetramethylene glycol, 2-methyltetrahydrofuran glycol, and 3-methyltetrahydrofuran glycol are preferred from the viewpoint of water absorption and viscosity. As the polyalkylene oxide, not only the homopolymer but also a random or block copolymer thereof can be used.

Examples of the diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, and p-isocyanate. Phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-
Examples include trimethylhexamethylene diisocyanate, and among them, 2,4-tolylene diisocyanate, isophorone diisocyanate and the like are preferable. These diisocyanates may be used alone or in combination of two or more.

Further, examples of the compound having a (meth) acrylic group include (meth) acrylic compounds having a hydroxyl group, an acid halide group, and an epoxy group.

The (meth) acrylic compound having a hydroxyl group includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerin di (meth) acrylate and the like. An adduct of a glycidyl group-containing compound such as alkyl glycidyl ether and glycidyl (meth) acrylate with (meth) acrylic acid may be mentioned.

Examples of the (meth) acrylic compound having an acid halide include (meth) acrylic chloride and (meth) acrylic bromide.

Examples of the (meth) acrylic compound having an epoxy group include glycidyl esters of (meth) acrylic acid.

Polyether polyurethane having at least two (meth) acryl groups in one molecule is, for example,
The above diol and diisocyanate are converted to OH / N
After reacting at CO = 0.5 to 2.0 (molar ratio), it can be further produced by reacting a compound having a (meth) acryl group.

The vinyl ether compound (B) of the present invention has the effect of lowering the viscosity of the polyether polyurethane (A) having at least two (meth) acryl groups in one molecule. Further, the present inventors have found that they have the effect of increasing the curing speed and reduce the water absorption of the cured film. Specific examples of vinyl ether compounds include compounds having one vinyl ether group in the molecule, such as ethyl vinyl ether, propyl vinyl ether, t-butyl vinyl ether, isobutyl vinyl ether, t-amyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether,
Examples include ethylene glycol butyl vinyl ether, triethylene glycol ethyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, aminopropyl vinyl ether, 2-diethylaminoethyl vinyl ether, and propenyl ether propylene carbonate. Vinyl ether compounds containing a hydroxy group in the molecule include ethylene glycol monovinyl ether, hydroxybutyl vinyl ether,
Hexanediol monovinyl ether, cyclohexane dimethanol monovinyl ether, diethylene glycol monovinyl ether and the like can be mentioned. Compounds containing two or more vinyl ether groups in the molecule include butanediol divinyl ether, hexanediol divinyl ether, 1,4-cyclohexane dimethanol divinyl ether, ethylene glycol divinyl ether, and the following general formula (1) CH ₂ ＝ CH— (OCH ₂ CH ₂ ) _m —OCH ＝ CH ₂ (1) wherein m is an integer of 2 to 20. In the above formula (1), the ethylene oxide group is propylene. Polypropylene glycol divinyl ether substituted with an oxide group,
Following general formula _{(2) CH 2 = CH- (} OCH 2 CH 2 CH 2 CH 2) n -OCH = CH 2 (2) ( wherein, n. Represents an integer of 2 to 20) represented by poly Examples thereof include divinyl ethers such as tetrahydrofuran vinyl ether, trivinyl ethers represented by trimethylolpropane trivinyl ether, and tetravinyl ethers represented by pentaerythritol tetravinyl ether. The above compounds having a vinyl ether group can be used alone or in combination of two or more.

The compounding amount of the vinyl ether compound is 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the polyether polyurethane having two (meth) acryl groups in one molecule. Is done. When the amount of the vinyl ether compound is less than 1 part by weight, the effect of accelerating the reaction when the viscosity is reduced or irradiated with radiation is small, and when the amount is more than 100 parts by weight, the effect of promoting the reaction when irradiated with the radiation is reduced although the effect of dilution is obtained.

In the present invention, a reactive diluent having a (meth) acrylic group and / or an N-vinyl group as the component (C) is blended for the purpose of adjusting the viscosity and adjusting the physical properties according to the intended use. be able to.

Specific examples of the (meth) acrylate compound [reactive diluent having a (meth) acrylic group] include:
For example, isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-butylcyclohexyl Contains alicyclic structure such as (meth) acrylate (meth)
Acrylate; glycidyl (meth) acrylate, 2-
(Meth) acrylates having an epoxy group or a hydroxyl group such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate; methyl (meth) acrylate;
Ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, amyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) Acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) Acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isosteary Alkyl (meth) acrylates such as (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, polyethylene glycol mono (Meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, dimethylaminoethyl (meth) Acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl ( Data) acrylate, and the following general formula (3) or (4) a compound represented by.

CH ₂ ＣC (R ¹ ) —COO (R ² O) _p —R ³ (3) (wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² has 2 to 6 carbon atoms, preferably Represents an alkylene group of 2 to 4;
³ represents a hydrogen atom or an alkyl group or an aryl group having 1 to 12, preferably 1 to 9 carbon atoms, and p represents a number of 0 to 12, preferably 1 to 8. ) CH ₂ ＣC (R ⁴ ) —CO (OR ⁵ CO) _q —OCH ₂ —THF (4) (wherein, R ⁴ has the same meaning as R ^1, and R ⁵ has 2 to 2 carbon atoms)
8, preferably 2 to 5 alkylene groups, THF represents a tetrahydrofuryl group, and q represents a number of 1 to 8, preferably 1 to 4. )

Such (meth) acrylate compounds include, for example, Aronix M-111, M-113, M-11
4, M-117 (manufactured by Toa Gosei Chemical); KAYAR
Commercially available products such as ADTC110S, R629 and R644 (all manufactured by Nippon Kayaku); Viscort 3700 (manufactured by Osaka Organic Chemicals) can be obtained. Further, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, 1,4-butanediol di (meth)
Acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropanetrioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2
-Hydroxyethyl) isocyanurate di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethylene oxide of bisphenol A or di (meth) acrylate of diol as an adduct of propylene oxide, ethylene oxide of hydrogenated bisphenol A Alternatively, di (meth) acrylate of a diol, which is an adduct of propylene oxide, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, and triethylene glycol divinyl ether may be used. Commercial products include, for example, Iupima UV SA1002, SA200
7 (all manufactured by Mitsubishi Chemical); Viscoat 700 (manufactured by Osaka Organic Chemical); KAYARAD R-604, R-684;
DPCA-20, DPCA-30, DPCA-60, D
PCA-120, HX-620, D-310, D-33
0 (all manufactured by Nippon Kayaku); Aronix M-210, M
-215, M-220, M-315, M-325 (all manufactured by Toagosei Chemical); Newpole BPE, BP, H
A60S (all manufactured by Sanyo Chemical Industries) and the like.

Specific examples of the N-vinyl compound [reactive diluent having an N-vinyl group] include N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-vinylformamide, N, N '-Divinylethylene urea and the like.

These (meth) acrylic groups and / or N-
The reactive diluent having a vinyl group can be used alone or in combination of two or more.

These (meth) acrylic groups and / or N-
The amount of the reactive diluent having a vinyl group is 2 per molecule.
1 to 200 parts by weight, especially 5 to 100 parts by weight of the polyether polyurethane having (meth) acrylic groups
It is preferable to use 150 parts by weight. If the amount is less than 1 part by weight, the effect of lowering the viscosity may be hardly obtained, and 200
If the amount is more than the weight part, the curability may be impaired, or the elongation of the cured product may be reduced.

(A), (B) and (C) described so far.
The composition containing the components is cured by irradiating an electron beam, but can be cured by irradiating ultraviolet rays by further adding a photoradical polymerization initiator or a photocationic polymerization initiator.

The photo-radical polymerization initiator includes, for example, xanthone, fluorenone, benzaldehyde, fluorene,
Anthraquinone, triphenylamine, carbazole,
1-hydroxycyclohexylphenyl ketone, 2,2
-Dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 4-chlorobenzophenone, 4,
4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-
Hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [ 4- (methylthio) phenyl]
-2-morpholino-propan-1-one, 2,4,6-
Trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,
4,4-trimethylpentylphosphine oxide; I
rgacure 184, 369, 651, 500, 90
7, CGI1700, CGI1750, CGI185
0, CG24-61, Darocure 4625, 11
73 (manufactured by Ciba Specialty Chemicals); L
ucirin TPO, LR8728 (manufactured by BASF); Ubecryl P36 (manufactured by UCB) and the like.

Examples of the cationic photopolymerization initiator include diaryliodonium salts, triarylsulfonium salts, triarylselenonium salts, dialkylphenacylsulfonium salts, triarylsulfonoxonium salts, aryloxydiarylsulfonoxonium salts, and dialkylphenadium salts. Onium salts such as silsulfonoxonium salts are effective, and specific examples include UVI-695
0, UVI-6970, UVI-6974, UVI-6
990 (all manufactured by Union Carbide), Adeka Optomer SP-150, SP-151, SP-170, SP
-171 (all manufactured by Asahi Denka Kogyo), Irgacure2
61 (all made by Ciba Specialty Chemicals), C
I-2481, CI-2624, CI-2639, CI
-2064 (all made by Nippon Soda), CD-1010, C
D-1011, CD-1012 (all manufactured by Sartomer), DTS-102, DTS-103, NAT-10
3, NDS-103, TPS-103, MDS-10
3, MPI-103, BBI-103 (all manufactured by Midori Kagaku) and the like. These photo-radical polymerization initiators and photo-cationic polymerization initiators can be used alone or in combination of two or more. The amounts used are (A), (B),
(C) 0.01 to 20 parts by weight based on a total of 100 parts by weight of the component.
Parts by weight, preferably 0.1 to 10 parts by weight.

The liquid radiation-curable resin composition of the present invention may further contain, if necessary, a sensitizer, an antioxidant, an ultraviolet absorber, an organic solvent, a plasticizer, a surfactant, a silane coupling agent, and a coloring agent. Additives such as pigments, organic or inorganic particles and the like can be added within a range that does not impair the purpose of the present invention.

The radiation for curing the liquid radiation-curable resin composition of the present invention includes infrared rays, visible rays, ultraviolet rays, and ionizing radiations such as X-rays, electron beams, α-rays, β-rays, and γ-rays.

In addition, a method of irradiating with radiation and curing,
As the condition, an ordinary method can be adopted, but electron beam irradiation is performed.
In the case of a voltage of 30 to 200 kV, especially 50 to 170 kV
Accelerate the electrons and absorb 10 to 100 kGy, especially 20
Irradiation at ~ 80 kGy is preferred. Also UV
In the case of irradiation, the irradiation amount is 10 to 2,000 mJ / c.
m ^Two, Especially 50 to 1,000 mJ / cm^TwoGood to be
Good.

When the composition of the present invention is used as a coating material for an optical fiber, it may be a primary coating material, a secondary coating material, or a taped material of an optical fiber core.

When the liquid radiation-curable resin composition of the present invention is used for a coating material for an optical fiber, it can be prepared by mixing the above-mentioned required components and then stirring and mixing. From the point of compatibility with the normal manufacturing conditions of the optical fiber core wire from 500 to 10,000 mPa.
s (25 ° C.), particularly 1,000-
A range of 6,000 mPa · s (25 ° C.) is desirable.

The case where the resin composition is used for a coating material for an optical fiber has been described above. However, the resin composition of the present invention is not limited to its use. For example, the resin composition is also applicable to a coating material for a cellular phone, a keyboard of a personal computer, and the like. It is possible to Depending on the application, it may be desirable that the viscosity be lower than the above-mentioned value.
By increasing the proportion of the component (B) and / or component (C), it is possible to adjust the value to, for example, 100 mPa · s or less.

[0038]

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. In addition, in the following examples, a part shows a weight part.

Example 1 Isobornyl acrylate 8
8.14 g, 2,4-tolylene diisocyanate
52 g, dibutyltin dilaurate 0.4 g, 2,6-
0.11 g of di-tert-butylhydroxytoluene was charged into a reaction vessel, and 93.21 g of 2-hydroxyethyl acrylate was added dropwise at a rate kept at 15 ° C. or lower under dry air. Then, after reacting at 30 ° C. for 2 hours, polypropylene glycol 11 having a number average molecular weight of 1,018
8.89 g was added and reacted at 50-60 ° C. for 3 hours,
An acrylic group-terminated polyether urethane oligomer (hereinafter referred to as oligomer A) containing 22.2% by weight of isobornyl acrylate was obtained. Sample 1 was prepared by mixing 90 parts by weight of oligomer A and 10 parts by weight of cyclohexane dimethanol divinyl ether. Its viscosity at 25 ° C. was 4,900 mPa · s.

This sample-1 was applied on a glass plate to a thickness of about 60 μm using an applicator, and the electron beam obtained by accelerating electrons at a voltage of 100 kV was used to absorb an electron beam at a dose of 1 kV.
Irradiation was performed at 0, 20, 30, and 100 kGy, and the curability was determined by gel fraction. In addition, the absorption rate is 30k
The case of curing with Gy was examined. Table 1 shows the results of measuring the properties of the cured film as described below.

Method for Measuring Film Properties (1) Gel Fraction After the cured film was immersed in acetone for 16 hours, the film was taken out, dried at 70 ° C. for 4 hours, and the weight change ratio was determined by the following equation. Gel fraction (%) = (film weight after drying / initial film weight) × 100 (2) Water absorption A cured film having a shape of 5 cm in length and 5 cm in width was cured at 50 ° C.
After drying for 4 hours to volatilize the uncured components, the film is immersed in pure water at 25 ° C. for 24 hours, weighed (measured value is set to (A)), and the film is taken out and taken out at 50 ° C. for 24 hours. After drying, the weight was measured (the measured value was defined as (B)), and the weight was determined by the following equation. Water absorption (%) = [((A)-(B)) / (B)] × 10
0

Example 2 Sample 2 was prepared by mixing 90 parts by weight of the oligomer A obtained in Example 1, 5 parts by weight of N-vinylcaprolactam, and 5 parts by weight of cyclohexanedimethanol divinyl ether. 25 ℃
Was 5,200 mPa · s. This sample-2 was cured with an electron beam in the same manner as in Example 1, and the properties of the cured film were measured. The gel fraction was almost the same as in Sample-1, and the water absorption was a slightly higher value.

Comparative Example 1 Sample 3 was prepared by mixing 90 parts by weight of the oligomer A obtained in Example 1 and 10 parts by weight of N-vinylcaprolactam. This sample did not contain a vinyl ether compound. 2 of this one
The viscosity at 5 ° C. was 5,500 mPa · s. This sample-3 was cured with an electron beam in the same manner as in Example 1, and the results of measuring the properties of the cured film are shown in Table 1.

Absorbed dose 10 kGy compared to samples 1 and 2
Was lower by about 3%, and the water absorption was 1.6% higher than that of Sample-1. From the above results, as the content of the vinyl ether compound was increased, 10 kGy
It was found that the curability was high and the water absorption was low.

In the above example, curing was carried out by an electron beam.
Next, an example in which curing is performed using ultraviolet light will be described.

Example 3 The oligomer A of Example 1 was replaced with 9
0 parts by weight, 10 parts by weight of cyclohexane dimethanol divinyl ether, and Irg as a photoradical polymerization initiator.
Acure 17000 (manufactured by Ciba Specialty Chemicals) (4 parts) was mixed to prepare Sample-4. Its viscosity at 25 ° C. was 4,700 mPa · s.

This sample-4 was applied to a thickness of about 200 μm on a glass plate using an applicator, and irradiated with ultraviolet rays having a wavelength of 350 nm under a nitrogen atmosphere at 25, 50, 100 and 50 μm.
Exposure was performed with an irradiation light amount of 0 mJ / cm ² to obtain a cured film. Table 1 shows the results of measuring the properties of the cured film.

Comparative Example 2 90 parts by weight of the oligomer A obtained in Example 1, 10 parts by weight of N-vinylcaprolactam, and 4 parts of Irgacure 1700 were mixed, and a sample -5 was prepared.
Was prepared. This sample does not contain a vinyl ether compound. Its viscosity at 25 ° C is 5,30.
It was 0 mPa · s. This sample-5 was cured with ultraviolet rays in the same manner as in Example 3, and the properties of the cured film were measured.
Shown in

The gel fraction was 1.2 to 1.4% lower than that of Sample-4 for all irradiation light amounts, and the water absorption decreased as the content of the vinyl ether compound increased as in the case of curing with an electron beam. Was confirmed.

[0050]

[Table 1]

[0051]

According to the present invention, a liquid radiation-curable resin composition having good curability and low water absorption can be obtained with a small radiation dose.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 6/44 301 G02B 6/44 301A 381 381 F term (Reference) 2H001 KK02 KK17 KK22 2H050 AB02Z BA18 BA20 BA32 BB13W BB14W BB33W BD05 4J011 QA08 QA39 QB24 QC03 SA06 SA25 SA26 SA27 SA36 SA54 SA63 SA64 SA84 SA87 UA01 UA04 VA01 WA03 4J027 AG04 AG09 AG14 AG23 AG24 AG27 BA04 BA08 BA09 BA13 BA26 CB10 CC05 CD03 4J0FA FA141 FA01FA1 FA GA07 GA08 JA07 JA32 JA34 JB06 JB27 JB39 JC17 JC18 JC22 KA03 MA14 NA07 NA24 PA17 PB08 PC03 PC08

Claims (4)

[Claims] (A) a number average molecular weight of from 800 to 10,000 having at least two (meth) acryl groups in one molecule;
100 parts by weight of a 00 polyether polyurethane,
(B) a compound having a vinyl ether group in the molecule of 1 to
A liquid radiation-curable resin composition comprising 100 parts by weight. 2. (A) a number average molecular weight of from 800 to 10,000 having at least two (meth) acryl groups in one molecule.
100 parts by weight of a 00 polyether polyurethane,
(B) a compound having a vinyl ether group in the molecule of 1 to
100 parts by weight, (C) (meth) acrylic group and / or N
-A liquid radiation-curable resin composition comprising 1 to 200 parts by weight of a reactive diluent having a vinyl group and a molecular weight of 500 or less. 3. A photo-radical polymerization initiator and / or a cationic photo-polymerization initiator, wherein (A) + (B) + (C) = 10
The liquid radiation-curable resin composition according to claim 1, wherein the liquid radiation-curable resin composition is contained in an amount of 0.01 to 20 parts by weight based on 0 part by weight. 4. A coating material for an optical fiber.
Or the composition according to 3.