JPH04270146A - Ultraviolet ray curing type resin composition for coating optical fiber - Google Patents

Abstract

PURPOSE:To improve the curing rate and reduce the amount of hydrogen produced from cured products by including a polymerizable unsaturated polyurethane, a monomer having ethylenically unsaturated bond and a photopolymerization initiator expressed by the prescribed formula. CONSTITUTION:The aforementioned ultraviolet ray curing type resin composition for coating optical fiber is obtained by including a polymerizable unsaturated polyurethane, a monomer having ethylenically unsaturated bond (e.g. tricyclodecanedimethanol diacrylate) and a photopolymerization initiator. The above-mentioned photopolymerization initiator is expressed by the general formula (R is H or alkyl group) and, e.g. 3,6-bis(2-morpholinoisobutyl)-9-butylcarbazole is used. When the aforementioned composition is used, the curing rate is increased to increase the wire drawing speed. Optical fiber coated with the resultant cured films is excellent in reliability for a long period with a small amount of hydrogen produced from the cured films.

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 optical fibers.

0002

[Prior Art] Optical fibers are extremely brittle and easily damaged.
Furthermore, it is well known that contamination increases optical transmission loss. For this reason, conventionally, immediately after spinning an optical fiber, the glass surface is first coated with a material having a low elastic modulus, and then a second coating is performed with a material having a high elastic modulus. In recent years, ultraviolet curing resins have been used as these materials from the viewpoint of productivity.

0003

[Problems to be Solved by the Invention] Conventional ultraviolet curable resins can be sufficiently irradiated with ultraviolet rays during the resin coating process when the spinning speed of the optical fiber is slow, and the resin cannot be sufficiently cured. can.

However, in order to improve the productivity of optical fiber strands, it is necessary to increase the spinning speed. but as a result,
There was a problem that there were many uncured parts.

[0005] Furthermore, hydrogen gas generated over time from a cured film made of a conventional ultraviolet curable resin has the problem of causing an increase in transmission loss of an optical fiber.

[0006] The problem to be solved by the present invention is to provide an ultraviolet curable resin composition for coating optical fibers that is sufficiently cured even with a small amount of ultraviolet irradiation and generates a small amount of hydrogen. be.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides (1) polymerizable unsaturated polyurethane, (2)
) Monomer having an ethylenically unsaturated bond and (3) general formula

[0008]

[Case 2]

[0009] An ultraviolet curable resin composition for coating an optical fiber is provided, which is characterized by containing a photopolymerization initiator represented by (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. Examples include a copolymer of , an ethylene oxide adduct of bisphenol A, and a propylene oxide adduct of bisphenol A. These commercially available products include "PEG 600" as polyethylene glycol.
”, “PEG 1000”, “PEG 2000”
(Manufactured by Sanyo Chemical Co., Ltd.); As polypropylene glycol,
“PPG Diol 1000”, “PPG Diol
2000”, “PPG Diol 3000” (manufactured by Mitsui Toatsu Chemical Co., Ltd.); “Excenol 1020”, “Excenol 2020”, “Excenol 302”
0" (manufactured by Asahi Glass Co., Ltd.); as polytetramethylene glycol, "PTG 650", "PTG 850",
“PTG 1000”, “PTG2000”, “PT
G 4000” (manufactured by Hodogaya Chemical Co., Ltd.); “ED-
28” (manufactured by Mitsui Toatsu), “Excenor 510”
(manufactured by Asahi Glass Co., Ltd.); “PPTG 1000” and “PPTG 1000” are copolymers of tetrahydrofuran and propylene oxide.
PPTG 2000”, “PPTG 4000” (
Manufactured by Hodogaya Chemical Co., Ltd.), “Unisafe DC-1100”
, "Unisafe 1800" (manufactured by NOF Corporation); "Unisafe DC-1100", "Unisafe
1800'' (manufactured by NOF Corporation); ``UNIOL DA-400'' is an ethylene oxide adduct of bisphenol A.
", "Uniol 700" (manufactured by NOF Corporation); and "UNIOL DB-400" (manufactured by NOF Corporation) as propylene oxide adducts of bisphenol A.

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 Examples include acrylate.

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

[0014] As the monomer having an ethylenically unsaturated bond used in the present invention, an acrylic ester compound is mainly used. When softness is required for the cured film, monofunctional (meth)acrylic ester compounds are used, and when hardness is required for the cured film, polyfunctional acrylic ester compounds with difunctionality or higher are used. is commonly used.

Specific examples of monomers having ethylenically unsaturated bonds used in the present invention include aromatic vinyl monomers such as styrene, chlorostyrene, divinylbenzene, etc.; substituents include methyl, ethyl, propyl, butyl, amyl; , 2-ethylhexyl, octyl, nonyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, nonylphenoxyethyl, tetrahydrofurfuryl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxy propyl, 3-chloro-
Acrylates, methacrylates or fumarates having groups such as 2-hydroxypropyl, dimethylaminoethyl, diethylaminoethyl, nonylphenoxyethyl, tetrahydrofurfuryl, etc.; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, Mono(meth)acrylates or poly(meth)acrylates such as tetramethylene glycol, hexamethylene glycol, trimethylolpropane, glycerin and pentaerythritol
Acrylate; 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, 2 or more moles of ethylene oxide or propylene per mole of neopentyl glycol Di(meth)acrylate of diol obtained by adding oxide, di- or tri(meth)acrylate of triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, 1 mole of bisphenol A Di(meth)acrylate of diol obtained by adding 2 moles or more of ethylene oxide or propylene oxide, reaction product of 1 mole of 2-hydroxyethyl (meth)acrylate and 1 mole of phenyl isocyanate or n-butyl isocyanate, Examples include poly(meth)acrylate of pentaerythritol.

[0016] Also, N-vinyl-2-pyrrolidone, acryloylmorpholine, vinylimidazole, vinylcaprolactam, vinyl-p-tert-butylbenzoate, cyclohexyl acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate. At least one monomer selected from the group consisting of: can also be used, and when used in combination with the above difunctional or higher (meth)acrylates, the curability improves, resulting in a high gel fraction after curing, providing a highly reliable material. 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]

[Chemical formula 3]

(However, R represents H or an alkyl group. )

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

Comparing with other known photopolymerization initiators, compound (3) has a particularly low ultraviolet irradiation amount of 20 mJ/c when used in an ultraviolet curable resin composition for coating optical fibers.
Polymerization and crosslinking reactions proceed more effectively when curing is performed with a small amount of irradiation light such as m2.

Compound (3) exhibits sufficient effects when used alone, but it can also be used in combination with other known photopolymerization initiators.

Examples of photopolymerization initiators that can be used in combination with compound (3) include benzyl dimethyl ketal,
Benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzylbenzophenone, 2-hydroxy-2-methylpropiophenone, 2,2-diethoxyacetophenone, anthraquinone, chloranthraquinone, ethyl anthraquinone,
Examples include aromatic ketones such as thioxanthone, chlorothioxanthone, and acylphosphine oxide, and dithiocarbamates.

[0024] In addition to these main ingredients, by using various auxiliary agents such as antioxidants and thermal polymerization inhibitors, it is possible to improve the storage stability of the paint and the weather resistance of the cured product. Coupling agents can also be used to control adhesion.

The ultraviolet resin composition for coating optical fibers of the present invention comprises (1) 10 to 80% by weight of a polymerizable unsaturated polyurethane, (2) 10 to 80% by weight of a monomer having an ethylenically unsaturated bond, and ( 3) 0.1 to 1 photopolymerization initiator
It is preferable that the content is in the range of 0% by weight.

[0026]

EXAMPLES Next, the present invention will be explained 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 1) 1 mole of polytetramethylene glycol (number average molecular weight 850) and 2 moles of 2,4-tolylene diisocyanate were charged into a reaction vessel equipped with a nitrogen gas introduction tube, a stirrer, and a cooling tube. The reaction was carried out at ℃ for 2 hours. Next, 2 moles of 2-hydroxypropyl 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 having an acryloyl group. A saturated polyurethane (A-1) was obtained.

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

Examples and comparative examples of the ultraviolet curable resin composition for coating optical fibers of the present invention are shown below.

(Example 1) 55 parts by weight of the polymerizable unsaturated polyurethane (A-1) obtained in Synthesis Example 1, 30 parts by weight of tricyclodecane dimethanol diacrylate ("Yupimer UV SA1002" manufactured by Mitsubishi Yuka Co., Ltd.) , N-vinyl-2
- 10 parts by weight of pyrrolidone and 1 part by weight of "A-CURE3" were mixed and dissolved at 60°C for 1 hour, and the viscosity was 39 poise (2
A liquid ultraviolet curable resin composition was obtained.

(Comparative Example 1) In Example 1, “A-C
Same as Example 1 except that 1 part by weight of benzyl dimethyl ketal was used instead of 1 part by weight of URE3.
A liquid ultraviolet 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 Toagosei Kagaku Co., Ltd.) and "A −
1 part by weight of "CURE3" was mixed and dissolved at 60°C for 1 hour.
A liquid ultraviolet curable resin composition having a viscosity of 43 poise (25° C.) was obtained.

(Comparative Example 2) In Example 2, “A-C
Same as Example 2 except that 1 part by weight of benzyl dimethyl ketal was used instead of 1 part by weight of URE3.
A liquid ultraviolet curable resin composition having a viscosity of 34 poise (25° C.) was obtained.

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

(Evaluation of curability) The ultraviolet curable resin composition was placed on a glass plate, and the dry coating thickness was that of Example 1 and Comparative Example 1.
The resin compositions obtained in Example 2 and Comparative Example 2 were coated to a thickness of 50 μm and 200 μm, respectively, and then irradiated in a nitrogen atmosphere using an 80 W/cm metal halide lamp. It was cured by changing the amount of light. The tensile modulus and gel fraction of the cured film were measured.

[0037] The tensile modulus is measured according to JIS K
7113. Regarding the gel fraction, the cured film was extracted with methyl ethyl ketone using a Soxhlet extractor for 3 hours or more, and the weight ratio before and after extraction was taken as the gel fraction.

(Measurement of hydrogen generation amount) After coating the ultraviolet curable resin composition on a glass plate so that the dry film thickness was 200 μm, irradiation was performed in a nitrogen atmosphere using an 80 W/cm metal halide lamp. It was cured at a light intensity of 200 mJ/cm2. Put 10g of this cured film into a headspace bottle and
After heating at 0° C. for 24 hours, measurement was performed by gas chromatography.

[0039]

[Table 1]

[0040]

Effects of the Invention The ultraviolet curable resin composition for coating optical fibers of the present invention has a faster curing speed than conventional ultraviolet curable resin compositions. Even when the amount is small, the uncured portion is small, the strength of the obtained cured film is sufficiently high, and the amount of hydrogen generated from the cured film is small.

Therefore, by using the ultraviolet curable resin composition for coating optical fibers of the present invention, it is possible to increase the drawing speed of optical fibers, thereby improving the productivity of optical fibers. The optical fiber coated with the ultraviolet curable resin composition for coating optical fiber of the invention is
High reliability can be obtained even during long-term use.

Claims (1)

[Claims] Claim 1: (1) Polymerizable unsaturated polyurethane, (
2) Monomer having an ethylenically unsaturated bond and (3)
An ultraviolet curable resin composition for coating an optical fiber, characterized by containing a photopolymerization initiator represented by the general formula: (R represents H or an alkyl group).