JPH0234620A - Photocurable resin composition - Google Patents

Abstract

PURPOSE:To obtain a rapid-curing photocurable resin composition desirable as a cladding material for optical fiber by adding a specified photopolymerization initialtor to the system in mixing a urethane-modified (meth)acrylate with both monofunctional and polyfunctional unsaturated compounds. CONSTITUTION:This photocurable resin composotion is formed by mixing a urethane-modified (meth)acrylate (A) with a resin component of a monofunctional unsaturated compound (B) (e.g., nonyl phenyl ether acrylate) and a polyfunctional unsaturated compound (e.g., trisacryloyloxyethyl isocyanurate) and a phosphine oxide compound (C) as a photopolymerization initiator, for example, 2,4,6- trimethylbenzoyldiphenylphosphine oxide. The mixing ratio of component A to component B is preferably 30-70 pts.wt. component A, 60-30 pts.wt. monofunctional unsaturated compound and 10-0 pt.wt. polyfunctional unsaturated compound per 100 pts.wt. total of components A and B for a primary cladding material. The amount of the photopolymerization initiator is 0.1-10wt.%, diesirably, 1-4wt.%, based on the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photocurable resin composition. More specifically, the present invention relates to a photocurable resin composition that has a fast curing speed and is suitable as a coating material for optical transmission glass fibers (herein abbreviated as optical fibers).

[Conventional technology]

In general, for optical fibers, the glass surface is first coated with a material with a low elastic modulus immediately after spinning to provide physical and chemical protection from the external environment, and then a second coat is applied with a material with a high elastic modulus. It is being done. Conventionally, silicone resins, nylon resins, or various ultraviolet curing resins have been used as these coating materials.

[Problem to be solved by the invention]

It is desired that coating materials for optical fibers have a fast curing speed in order to increase the productivity of optical fibers not only from the viewpoint of performance but also from an economical point of view. -Next Silicone resin as a coating material has a low elastic modulus and a glass transition temperature, so it has excellent transmission properties, but its slow curing speed does not increase productivity and is economically disadvantageous. In addition, conventionally proposed UV-curable coating materials such as epoxy acrylate, urethane acrylate, and polybutadiene acrylate have advantages over silicone resins in terms of curing speed and are currently widely used. .

However, in recent optical fiber production, in order to increase productivity, the optical fiber drawing speed has increased from the conventional 60 to 100 m/min to 300 m/min, and along with this, the curing speed is even faster. There is a need for UV-curable coating materials. The various UV-curable coating materials currently in use do not fully meet this requirement.

The present invention provides a coating material that has a fast curing speed and can increase the productivity of optical fibers.

[Means to solve problems]

As a result of various studies, the present inventors found that a composition consisting of urethane-modified (meth)acrylate, a monofunctional unsaturated compound, a polyfunctional unsaturated compound, and a photopolymerization initiator with a specific structure has a fast curing speed and is suitable for optical fibers. The present inventors have discovered that high-speed coating is possible, and that optical fibers coated with this composition exhibit excellent transmission characteristics, leading to the present invention.

The present invention contains (A) urethane-modified (meth)acrylate, (B) a monofunctional unsaturated compound and a polyfunctional unsaturated compound, and (C) a phosphine oxide compound as a photopolymerization initiator. The present invention provides a photocurable resin composition characterized by the following.

The expression (meth)acrylate used in the present invention means both acrylates and methacrylates. Other (meth)acryloyl groups (meth)acrylic acid,
The same applies to expressions such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate.

(A) Urethane modified (meth) used in the present invention
Acrylate means (a) polyisocyanate compound,
It is a compound obtained by reacting a polyhydroxy compound and (C) an unsaturated monohydroxy compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule. The polyisocyanate compound (a) mentioned above is a substance having two or more isocyanate groups in the molecule, and specific examples thereof include 2.4-) lylene diisocyanate, 2.6-tolylene diisocyanate, and diphenylmethane-4,4. Diisocyanate compounds such as '-diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, dimers and trimers of these diisocyanate compounds, and combinations of these diisocyanate compounds with ethylene glycol, hexanediol, trimethylolpropane, and glycerin. Examples include compounds obtained by reacting polyols such as hexanetriol under conditions in which isocyanate groups are excessive. These polyisocyanate compounds may be used alone or in combination of two or more.

The polyhydroxy compound (b) mentioned above is preferably a compound having two or more hydroxyl groups in the molecule and having a molecular weight of 700 or more, and specific examples thereof include polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, and propylene. Polyether polyols such as glycol-tetrahydrofuran copolymers, polyester polyols obtained by reacting adipic acid or dodecanedicarboxylic acid with the above-mentioned polyols, diethylene glycol, polypropylene glycol, etc., polycaprolactone polyols, and saturated polyolefins having terminal hydroxyl groups. Examples include.

If the molecular weight of these polyhydroxy compounds is less than 700, the modulus of elasticity will be high in the case of the primary coating material for optical fibers, which is unfavorable in terms of transmission characteristics, and the modulus of elasticity will be high and the elongation will be low in the case of the secondary coating material. This is not desirable because the balance between elastic modulus and elongation is poor.

Examples of the unsaturated monohydroxy compound (C) mentioned above include 2-hydroxyethyl (meth)acrylate, 2
- Hydroxyalkyl (meth)acrylates such as hydroxypropyl (meth)acrylate, N-hydroxyalkyl (meth)acrylamides such as N-hydroxymethyl (meth)acrylamide, ethylene glycol mono(meth)acrylate, diethylene glycol mono(meth) acrylate, (poly)alkylene glycol mono(meth)acrylate such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, trimethylolbroban di(meth)acrylate, glycidyl(meth)acrylate
Examples include equimolar reaction products of acrylate and (meth)acrylic acid, and these can be used alone or in combination of two or more.

The amounts of (a), Φ) and (C) are usually 1.1 to 2.0 equivalents of a) and 0.1 to 1.2 equivalents of (C) per equivalent of Q)), preferably ( b) For 1 equivalent (a) 1.
2 to 1.8 equivalents, and (c) 0.2 to 1.0 equivalents.

Furthermore, the order of reactions (a), (b), and (C) is not particularly limited; for example, (a), (b), and (C) are reacted at the same time, or (a) and (bl are reacted, and then There is a method of reacting (C) or reacting (a) with (C) and then reacting 0)), and the reaction temperature is usually about 20°C to 15°C.
0''C. At this time, a common urethanization reaction catalyst such as triethylamine or dibutyltin dilaurate is used to accelerate the reaction, or benzoquinone, hydroquinone, or hydroquinone is used to prevent the polymerization of the (meth)acryloyl group. monomethyl ether, catechol,
A common radical polymerization inhibitor such as phenothiazine may be used, or air or oxygen may be introduced into the reaction system.

The terminal of the urethane-modified (meth)acrylate of the present invention is usually a (meth)acryloyl group, but it may also be a -partial isocyanate group or a hydroxyl group.

The monofunctional unsaturated compound (B) used in the present invention is a compound containing one (meth)acryloyl group in the molecule, or a compound containing one (meth)acryloyl group in the molecule, which is N-vinylpyrrolidone. Examples of compounds include 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, phenoxyethyl (meth)acrylate, ethylene glycol nonylphenyl (
meth)acrylate, trepropylene glycol nonylphenyl ether (meth)acrylate, (meth)acrylic acid adduct of butyl glycidyl ether, (meth)acrylate of tetrahydrofurfuryl alcohol caprolactone adduct, hydroxyethyl (meth)acrylate, hydroxypropyl ( meth)acrylate, cyclohexyl(meth)acrylate, isobornyl(meth)
Examples include acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and the like. These may be used alone or in combination of two or more.

Furthermore, a polyfunctional unsaturated compound is a compound having two or more (meth)acryloyl groups in the molecule, such as ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butane. Diol (meth)acrylate, bisphenol A/ethylene oxide adduct di(meth)acrylate, bisacryloyloxyethyl hydroxyethyl isocyanurate, trisacryloyloxyethyl isocyanurate, trimethylolpropane tri(meth)acrylate,
Examples include dipentol hexa(meth)acrylate. These may be used alone or in combination of two or more.

In the present invention, when the ratio of (A) and (B) is 100 parts by weight, the ratio of (A) and (B) is usually 30 parts by weight of urethane-modified (meth)acrylate in the case of a second coating material.
~70 parts by weight, the monofunctional unsaturated compound is 60~70 parts by weight
30 parts by weight, and preferably 10 to 0 parts by weight of the polyfunctional unsaturated compound. If the amount of urethane-modified (meth)acrylate is less than 30 parts by weight, or if the total of monofunctional unsaturated compounds and polyfunctional unsaturated compounds exceeds 70 parts by weight, the viscosity of the coating material is too low and it is difficult to coat it during operation. It becomes difficult. On the other hand, if the urethane-modified (meth)acrylate exceeds 70 parts by weight, or if the total of monofunctional unsaturated compounds and polyfunctional unsaturated compounds is less than 30 parts by weight, the elastic modulus of the coating material increases and the transmission characteristics becomes worse. In the case of the secondary coating material, the monofunctional unsaturated compound is usually 30 to 10 parts by weight, and the polyfunctional unsaturated compound is 40 to 20 parts by weight, relative to 30 to 70 parts by weight of the urethane-modified (meth)acrylate. If the urethane-modified (meth)acrylate is less than 30 parts by weight, or the total of the monofunctional unsaturated compound and polyfunctional unsaturated compound exceeds 70 parts by weight, the urethane-modified (meth)acrylate The toughness is insufficient, the balance between elastic modulus and elongation is poor, and the transmission properties of the coating material are poor. If the total amount of unsaturated compounds is less than 1 part, the viscosity of the coating material will be too high, making coating difficult.

As the phosphine oxide compound as the polymerization initiator (C) used in the present invention, 2.4.6-dolimethylbenzoyldiphenylphosphine oxide (
The proportion of the phosphine oxide compound (Lucirin LR-8728) manufactured by BASF is usually 0.1% to 10% by weight, preferably 1% to 4% by weight of the resin composition of the present invention. It is. If it is less than 0.1% by weight, the effect of increasing the curing speed is insufficient, and if it exceeds 10% by weight, the desired physical properties of the photocurable resin composition may deteriorate.

Further, other photopolymerization initiators can also be used if necessary. These photoinitiators include benzoyl, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, benzyl, benzophenone, 2-hydroxy-2-methylpropiophenone, 2,2-jethoxyacetophenone, benzyl dimethyl ketal, anthraquinone, Chloranthraquinone,
Examples include ethyl anthraquinone, butylanthraquinone, diphenyl sulfide, dithiocarbamate, 2chlorothioxanthone, α-chloromethylnaphthaleneanthracene, 3.3', 4.4'-tetra-(t-butylperoxycarbonyl)benzophenone, and the like. Furthermore, amines such as Michler's ketone, triethylamine, and alkylmorpholine may be used in combination with these photopolymerization initiators.

Furthermore, the photocurable resin composition of the present invention can also contain various additives such as a silane coupling agent, an antioxidant, and a filler, if necessary.

Glass for optical fibers is quartz-based glass, and the main component is silica. This quartz base material is heated to about 2000°C and spun to an outer diameter of 125±3μ at a drawing speed of 60 to 300 m/min to obtain an optical fiber. The coating material is applied to the optical fiber by passing the optical fiber immediately after spinning through a tank containing the coating material. −
The coating thickness of the next coating material is usually 200~200mm in outer diameter after curing.
300μ, preferably 250μ, and the coating thickness of the secondary coating material is adjusted so that the outer diameter after curing is usually 400 to 900μ, preferably 400μ.

A typical method for curing is to irradiate the coated optical fiber with ultraviolet rays in a nitrogen gas atmosphere using a high-pressure mercury lamp.

〔Example〕

The present invention will be explained below with reference to Synthesis Examples, Examples, and Comparative Examples.

Synthesis Example 1 300 parts by weight of polyoxytetramethylene glycol with a molecular weight of 1000, 2.4-tolylene diisocyanate 7
When 8 parts by weight were charged into a 500 ad flask equipped with a stirrer and a thermometer and reacted at 70° C. for 4 hours under a nitrogen stream, the NGO groups were reduced to 1/3 of the initial amount.

Next, 38 parts by weight of hydroxyethyl acrylate, 0.2 parts by weight of hydroquinone, and 0.1 parts by weight of dibutyltin dilaure were added to this reaction solution, and the mixture was further reacted at 70'C for 5 hours while bubbling air into the reaction solution. Then, urethane-modified (meth)acrylate (A-1) was synthesized.

Synthesis Example 2 300 parts by weight of polyoxytetramethylene glycol with a molecular weight of 12,000, 42 parts by weight of hexamethylene diisocyanate
Part by weight was charged into a flask equipped with a 500 ad stirrer and a thermometer, and the mixture was reacted at 70° C. for 5 hours under a nitrogen stream, and the NGO group became the initial 275.

Next, add hydroxypropyl acrylate 27 to this reaction solution.
parts by weight, 0.2 parts by weight of hydroquinone, and 0.1 parts by weight of dibutyltin dilaurate were added, and the reaction was further carried out at 70°C for 5 hours while bubbling air into the reaction solution to obtain urethane-modified (meth)acrylate (A-2). Synthesized.

Synthesis Example 3 Propylene oxide-tetrahydrofuran copolymer with molecules 12,000 (Odogaya Chemical: PPTG2000) 3
00 parts by weight, 2.4-) lylene diisocyanate 39
．． 2 parts by weight were placed in a 500 d flask equipped with a stirrer and a thermometer, and the mixture was reacted at 70°C for 6 hours under a nitrogen stream, resulting in an NGO group of 173.Next, hydroxyethyl was added to the reaction solution. Add 18.3 parts by weight of acrylate, 0.2 parts by weight of hydroquinone, and 0.11 parts of dibutyltin dilaurate, and react for an additional 5 hours while bubbling air into the reaction solution to modify the urethane (meth).
Acrylate (A-3>) was synthesized.

Example 1 To 50 parts by weight of the urethane-modified (meth)acrylate (A-1) obtained in Synthesis Example 1, 10 parts by weight of the structural formula (Toa Gosei type?l-117) as a monofunctional unsaturated compound, and 40 parts by weight of structural formula (Nippon Kaso TC-1105) were added, and 2 parts by weight of 2°4.6-trimethylbenzoyldiphenylphosphine oxide were added and stirred to obtain a second coating material.

Example 2 50 parts by weight of the urethane-modified (meth)acrylate (A-2) obtained in Synthesis Example 2 was added with 50 parts by weight of a monofunctional unsaturated compound (Structural formula % formula %) (Toagosei type M-120) In addition, 2 parts by weight of 2,4.6-trimethylbenzoyldiphenylphosphine oxide was added and mixed and stirred to obtain a second coating material.

Example 3 To 50 parts by weight of the urethane-modified (meth)acrylate (^-3) obtained in Synthesis Example 3, 10 parts by weight of the structural formula (Toa Gosei type M-111) as a monofunctional unsaturated compound and 120
4 parts by weight were added thereto, and 2 parts by weight of 2,4.6-trimethylbenzoyldiphenylphosphine oxide was added thereto and mixed and stirred to obtain a second coating material.

Example 4 To 50 parts by weight of the urethane-modified (meth)acrylate (A-3) obtained in Synthesis Example 3, 1 part by weight of To111 and 40 parts by weight of To120 were added as monofunctional unsaturated compounds,
Further, 1 part by weight of 2.4.6-)limethylbenzoyldiphenylphosphine oxide and 1 part by weight of benzyl dimethyl ketal were added and mixed with stirring to obtain a second coating material.

Example 5 To 50 parts by weight of the urethane-modified (meth)acrylate (^-1) obtained in Synthesis Example 1, 1 part of a monofunctional unsaturated compound (Structural formula % Formula % Toagosei type L150) was added, and Add 1 part of structural formula (PO-A manufactured by Kyoeisha Yushi Co., Ltd.), further add 20 parts by weight of structural formula % formula % (Toagosei type M-315) as a polyfunctional unsaturated compound, 4.6-) 2 parts by weight of lymethylbenzoyldiphenylphosphine oxide was added and mixed and stirred to obtain a secondary coating material.

Example 6 Urethane-modified (meth)acrylate obtained in Synthesis Example 1)
(A-1) 10 parts by weight of To150 as a monofunctional unsaturated compound and 20 parts by weight of PO-A are added to 50 parts by weight, and further 20 parts by weight of M-315 is added as a polyfunctional unsaturated compound, To this, 1 part by weight of 2,4.6-)limethylbenzoyldiphenylphosphine oxide was added,
Furthermore, 1 part by weight of benzyl dimethyl ketal was added and mixed and stirred to obtain a secondary coating material.

Comparative Example 1 A primary coating material was obtained with the same composition as in Example 1 except that 912 parts by weight of 2.4.6-)trimethylbenzoyldiphenylphosphine oxide was replaced with 2 parts by weight of benzyl dimethyl ketal.

Comparative Example 2 With the same composition as Example 3, 2 parts by weight of 2.4.6-)dimethylbenzoyldiphenylphosphine oxide were added to
A primary coating material was obtained by replacing 2 parts by weight of 2-jethoxyacetophenone.

Comparative Example 3 A secondary coating material was obtained with the same composition as in Example 5 except that 2 parts by weight of 2,4.6-trimethylbenzoyldiphenylphosphine oxide was replaced with 2 parts by weight of benzyl dimethyl ketal.

The following evaluations were performed on the coating materials obtained in each of the above cases. The results are shown in Table-1 and Table-2.

The evaluation was performed using the following method.

l) Curing speed The coating material was applied to a thickness of approximately 100μ on a glass plate, and several types of cured films were created by irradiating the coating material with ultraviolet rays in a nitrogen gas atmosphere using an 80W/Cl high-pressure mercury lamp at varying doses. Next, this film was extracted with methyl ethyl ketone in a Soxhlet extractor for 12 hours, and the gel content was measured by the weight ratio before and after extraction.The minimum amount of ultraviolet irradiation required for the gel content to reach a constant value was determined, and this value was calculated as the curing rate. was used as a scale.

2) Transmission loss The primary coating material obtained in Examples 1 to 4 was combined with the secondary coating material obtained in Example 5, and the secondary coating material obtained in Examples 5 to 6 was combined with the secondary coating material obtained in Example 1. In addition, the primary coating materials obtained in Comparative Examples 1 and 2 were combined with the secondary coating material obtained in Comparative Example 3 to form coated optical fibers in the following manner. obtain.

Immediately after spinning the primary coating material onto an optical fiber with an outer diameter of 125μ spun at a speed of 300 m/min, the outer diameter after curing is 250 μm.
Immediately apply 0-order secondary coating material cured in a nitrogen atmosphere using a high-pressure mercury lamp (3.2) so that the outer diameter after curing is 400μ, and then apply Cure under the same conditions as the coating material. These coated optical fibers thus obtained were heated at 23°C and -40°C at a wavelength of 1.3μ.
The photoconductive loss at °C was measured.

[Effects of the Invention] As explained above, the coating material of the present invention has a fast curing speed,
It enables high-speed coating of optical fibers and increases productivity. Moreover, the optical fiber coated with the coating material has a remarkable effect of having excellent conduction properties.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] (A) a urethane-modified (meth)acrylate, (B) a monofunctional unsaturated compound and a polyfunctional unsaturated compound, and (C) a phosphine oxide compound as a photopolymerization initiator. A photocurable resin composition characterized by containing: