JP3134269B2 - UV curable resin composition for optical fiber coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet curable resin composition for coating an optical fiber.

[0002]

2. Description of the Related Art Optical fibers are very brittle and easily damaged.
It is well known that optical transmission loss increases due to contamination. For this reason, conventionally, immediately after spinning of an optical fiber, a primary coating is performed on a glass surface with a material having a low elastic modulus, and then a secondary coating is performed with a material having a high elastic modulus. In recent years, ultraviolet curable resins have been used as these materials from the viewpoint of productivity.

[0003]

When the spinning speed of the optical fiber is low, the conventional ultraviolet curable resin can sufficiently irradiate ultraviolet rays in the resin coating step, and the resin can be sufficiently cured. it can.

[0004] However, in order to improve the productivity of the optical fiber strand, it is necessary to increase the spinning speed. However, when the spinning speed is increased, the amount of the applied ultraviolet ray to the applied ultraviolet curable resin is not sufficient. But as a result,
There was a problem that uncured portions increased.

In addition, hydrogen gas generated with time from a cured film made of a conventional ultraviolet curable resin has a problem of causing an increase in transmission loss of an optical fiber.

The problem to be solved by the present invention is to provide an ultraviolet-curable resin composition for coating an optical fiber, which cures sufficiently even with a small amount of irradiation of ultraviolet light and generates a small amount of hydrogen. is there.

[0007]

In order to solve the above-mentioned problems, the present invention provides (1) a polymerizable unsaturated polyurethane,
(2) a monomer having an ethylenically unsaturated bond and (3) a general formula

[0008]

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[0009] Provided is an ultraviolet curable resin composition for coating an optical fiber, characterized by containing a photopolymerization initiator represented by the following (wherein R represents H or an alkyl group).

The polymerizable unsaturated polyurethane used in the present invention can be obtained by reacting a hydroxy compound having a polyoxyalkylene block, a hydroxy compound having an acryloyl group, and a polyisocyanate.

Examples of the hydroxy compound having a polyoxyalkylene block include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, a copolymer of propylene oxide and ethylene oxide, a copolymer of tetrahydrofuran and propylene oxide, and a copolymer of tetrahydrofuran and ethylene oxide. , An ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, and the like. As these commercially available products, "PEG 600" as polyethylene glycol,
"PEG 1000", "PEG 2000" (manufactured by Sanyo Chemical Industries); "PPG diol 100
0 "," PPG diol 2000 "," PPG diol 3000 "
(Mitsui Toatsu Chemical Co., Ltd.); "Exenol 1020", "Exenol 2020", "Exenol 3020" (Asahi Glass Co., Ltd.); "PTG" as polytetramethylene glycol
650 "," PTG 850 "," PTG 1000 "," PTG2000 ",
"PTG 4000" (manufactured by Hodogaya Chemical Co., Ltd.); "ED-28" as a copolymer of propylene oxide and ethylene oxide
(Manufactured by Mitsui Toatsu), "Exenol 510" (manufactured by Asahi Glass Co.); "PPTG 1000", "PPTG 2000", "PPTG" as a copolymer of tetrahydrofuran and propylene oxide
4000 "(made by Hodogaya Chemical Co., Ltd.)," Unisafe DC-110
0 "," Unisafe 1800 "(manufactured by NOF Corporation); as copolymers of tetrahydrofuran and ethylene oxide," Unisafe DC-1100 "and" Unisafe 1800 "(manufactured by NOF Corporation); as bisethylene A ethylene oxide adduct UNIOL DA-400, UNIOL 70
0 "(manufactured by NOF Corporation); Examples of the propylene oxide adduct of bisphenol A include" Uniol DB-400 "(manufactured by NOF Corporation).

Examples of the hydroxy compound having an acryloyl group include hydroxyethyl acrylate, 2
-Hydroxypropyl acrylate, 2-hydroxybutyl acrylate, phenoxyhydroxypropyl acrylate, butoxyhydroxypropyl acrylate,
Pentaerythritol acrylate, dipentaerythritol monohydroxypentaacrylate, trimethylolpropane diacrylate, dipropylene glycol monoacrylate, 1,6-hexanediol monoacrylate, glycerin diacrylate, caprolactone-modified 2-hydroxyethyl acrylate, stearic acid-modified pentaerythritol diacrylate Acrylate and the like can be mentioned.

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

As the monomer having an ethylenically unsaturated bond used in the present invention, an acrylate compound is mainly used. When a cured film requires softness, a monofunctional (meth) acrylate compound is used. When a cured film requires hardness, a bifunctional or higher polyfunctional acrylate compound is used. Is generally used.

Specific examples of the monomer having an ethylenically unsaturated bond used in the present invention include aromatic vinyl monomers such as styrene, chlorostyrene and divinylbenzene; and methyl, ethyl, propyl, butyl and amyl as substituents. , 2-ethylhexyl, octyl, nonyl,
Dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, nonylphenoxyethyl, tetrahydrofurfuryl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxy Acrylate, methacrylate or fumarate having a group such as propyl, dimethylaminoethyl, diethylaminoethyl, nonylphenoxyethyl, tetrahydrofurfuryl, etc .; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol , Hexamethylene glycol,
Mono (meth) acrylates or poly (meth) acrylates such as trimethylolpropane, glycerin and pentaerythritol; vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile, cetyl vinyl ether,
Limonene, cyclohexene, diallyl phthalate, 2
-, 3- or 4-vinylpyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide or N-hydroxyethylacrylamide and their alkyl ether compounds,
Di (meth) acrylate of diol obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol, and 3 mol or more of ethylene oxide or propylene oxide added to 1 mol of trimethylolpropane Diol or tri (meth) acrylate of triol, bisphenol A1
Reaction product of 1 mol of di (meth) acrylate, 2-hydroxyethyl (meth) acrylate of diol obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of diol and 1 mol of phenyl isocyanate or n-butyl isocyanate And poly (meth) acrylate of dipentaerythritol.

Further, N-vinyl-2-pyrrolidone, acryloylmorpholine, vinylimidazole, vinylcaprolactam, vinyl-p-tert-butylbenzoate, cyclohexyl acrylate, isobornyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl acrylate At least one monomer selected from the group consisting of: can be used, and when used in combination with the above-mentioned (meth) acrylate having two or more functionalities, the curability is improved, a high gel fraction is obtained after curing, and a highly reliable material is provided. be able to.

The photopolymerization initiator used in the present invention is a compound represented by the following general formula (hereinafter, referred to as compound (3)).

[0018]

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(Where R represents H or an alkyl group)

As a commercially available product of this compound (3), for example, Asahi Denka Kogyo Co., Ltd. product name “A-CURE3” (3,3)
6-bis (2-morpholinoisobutyl) -9-butylcarbazole).

When compound (3) is used in an ultraviolet-curable resin composition for coating an optical fiber, it has an ultraviolet irradiation dose of 20 mJ / cm when compared with other known photopolymerization initiators.
^When cured with a small amount of irradiation light, such as ² , the polymerization and crosslinking reactions proceed more effectively.

The compound (3) exerts its effect sufficiently even when used alone, but can also be used in combination with other known photopolymerization initiators.

Examples of the photopolymerization initiator which can be used in combination with the compound (3) include, for example, benzyldimethyl ketal,
Benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzylbenzophenone, 2-hydroxy-2-methylpropiophenone, 2,2-diethoxyacetophenone, anthraquinone, chloranthraquinone, ethylanthraquinone,
Aromatic ketones such as thioxanthone, chlorothioxanthone and acylphosphine oxide, and dithiocarbamates are exemplified.

In addition to these main components, various auxiliary agents such as an antioxidant and a thermal polymerization inhibitor can be used in combination to improve the storage stability of the coating and to improve the weather resistance of the cured product. Alternatively, a coupling agent can be used to control the adhesiveness.

The ultraviolet resin composition for coating an optical fiber of the present invention comprises (1) 10 to 80% by weight of a polymerizable unsaturated polyurethane and (2) 10% by weight of a monomer having an ethylenically unsaturated bond.
It is preferable to add the photopolymerization initiator in the range of 0.1 to 10% by weight.

[0026]

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 described.

(Synthesis Example 1) 1 mol of polytetramethylene glycol (number average molecular weight: 850) and 2 mol of 2,4-tolylene diisocyanate were charged into a reaction vessel equipped with a nitrogen gas introducing pipe, a stirrer and a cooling pipe. The reaction was carried out at 2 ° C. for 2 hours. Next, 2 mol of 2-hydroxypropyl acrylate, a trace amount of t-butylhydroquinone as a polymerization inhibitor and a trace amount of dibutyltin dilaurate as a catalyst are gradually added, and the mixture is further reacted at 70 ° C. for 5 hours to obtain a polymerizable polymer having an acryloyl group. A saturated polyurethane (A-1) was obtained.

(Synthesis Example 2) Polypropylene glycol (number-average molecular weight of 4,000) was used instead of 1 mol of polytetramethylene glycol (number-average molecular weight of 850) in Synthesis Example 1.
0) In the same manner as in Synthesis Example 1 except that 1 mol was used,
Polymerizable unsaturated polyurethane having an acryloyl group (A
-2) was obtained.

Hereinafter, examples and comparative examples of the ultraviolet curable resin composition for coating an optical fiber of the present invention will be described.

(Example 1) 55 parts by weight of the polymerizable unsaturated polyurethane (A-1) obtained in Synthesis Example 1 and tricyclodecane dimethanol diacrylate ("Iupimer U" manufactured by Mitsubishi Yuka Co., Ltd.)
V SA1002 ”), 30 parts by weight of N-vinyl-2-pyrrolidone and 1 part by weight of“ A-CURE3 ”at 60 ° C.
After mixing and dissolving for hours, a liquid UV-curable resin composition having a viscosity of 39 poise (25 ° C.) was obtained.

Comparative Example 1 In Example 1, "AC
In the same manner as in Example 1 except that 1 part by weight of benzyl dimethyl ketal was used instead of 1 part by weight of URE3 ”,
A liquid UV-curable resin composition having a viscosity of 42 poise (25 ° C.) was obtained.

(Example 2) 55 parts by weight of the polymerizable unsaturated polyurethane (A-2) obtained in Synthesis Example 2, 45 parts by weight of nonylphenoxy polypropylene glycol acrylate ("Aronix M117" manufactured by Toa Gosei Chemical Co., Ltd.) and "A -CUR
One part by weight of E3 was mixed and dissolved at 60 ° C. for 1 hour to obtain a liquid ultraviolet curable resin composition having a viscosity of 43 poise (25 ° C.).

Comparative Example 2 In Example 2, "AC
In the same manner as in Example 2 except that 1 part by weight of benzyl dimethyl ketal was used instead of 1 part by weight of URE3,
A liquid UV-curable resin composition having a viscosity of 34 poise (25 ° C.) was obtained.

The following evaluations were carried out using each of the ultraviolet-curable resin compositions obtained in Examples 1 and 2 and Comparative Examples 1 and 2, and the results are shown in Table 1.

(Evaluation of Curability) The ultraviolet-curable resin composition was placed on a glass plate, and the thickness of the dried coating film was determined in Example 1 and Comparative Example 1.
Each of the resin compositions obtained in the above was applied so as to have a thickness of 50 μm, and the resin compositions obtained in Example 2 and Comparative Example 2 were each applied so as to have a thickness of 200 μm. The composition was cured by changing the amount of light. The tensile modulus and gel fraction of the cured film were measured.

The tensile modulus was measured according to JIS K71.
Performed according to 13. Regarding the gel fraction, the cured film was extracted with methyl Sodium extractor for 3 hours or more using methyl ethyl ketone, and the weight ratio before and after the extraction was defined as the gel fraction.

(Measurement of Hydrogen Generation Amount) An ultraviolet curable resin composition was applied on a glass plate so as to have a dry coating thickness of 200 μm, and then irradiated in a nitrogen atmosphere using an 80 W / cm metal halide lamp. Curing was performed at a light intensity of 200 mJ / cm ² .
Put 10 g of this cured film in a headspace bottle,
After heating for 24 hours, measurement was performed by gas chromatography.

[0039]

[Table 1]

[0040]

The ultraviolet-curable resin composition for coating an optical fiber of the present invention has a higher curing speed than the conventional ultraviolet-curable resin composition. Even when the amount is small, the uncured portion is small, the strength of the obtained cured film is sufficiently large, and the amount of hydrogen generated from the cured film is small.

Therefore, when the ultraviolet curable resin composition for coating an optical fiber of the present invention is used, the drawing speed of the optical fiber can be increased, so that the productivity of the optical fiber can be improved. An optical fiber coated with the ultraviolet-curable resin composition for coating an optical fiber of the present invention,
High reliability can be obtained even in long-term use.

Claims (1)

(57) [Claims] (1) a polymerizable unsaturated polyurethane,
(2) a monomer having an ethylenically unsaturated bond and (3) a general formula: (Where R represents H or an alkyl group). An ultraviolet-curable resin composition for coating an optical fiber, comprising a photopolymerization initiator represented by the following formula: