JPH01201317A - Coating composition for optical fiber - Google Patents

Abstract

PURPOSE:To make it possible to form a coating composition for optical fiber, especially excelling in properties after being immersed in hot water and having a high refractive index, by using a polyurethane poly(meth)acrylate prepared from a specified polyol component as the base material. CONSTITUTION:This composition comprises a polyurethane poly(meth)acrylate (a) obtained by reacting a brominated bisphenol/alkylene oxide adduct as a polyol component with a diisocyanate compound and a hydroxyl group- containing (meth)acrylate, a compound (b) having at least one polymerizable double bond in the molecule and a photopolymerization initiator (c), wherein the (a) to (c) weight ratio is 30/70-95/5, and the amount of component (c) is 0.1-10wt.% based on the weight of the composition. As said component (b), polyethylene glycol (2-ethylhexyl) ether acrylate is particularly preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composition suitable for coating optical fibers for light transmission.

[Conventional technology]

In recent years, optical fibers have been used for a variety of communication purposes, and inorganic optical glass fibers are used to prevent scratches on the glass in subsequent processes, prevent deterioration of the fiber, and prevent microhenting, which causes attenuation of optical signals. To prevent this, a protective coat is applied immediately after drawing, improving the reliability of the optical fiber.

As this protective coat, for example, one using a thermosetting resin such as a silicone resin, an epoxy resin, or a urethane resin is known. However, these thermosetting materials require a long time to cure and dry, resulting in poor optical fiber productivity.

Therefore, in order to improve productivity, epoxy (meth)acrylate (hereinafter, "acrylate" and "methacrylate" are collectively referred to as "(meth)acrylate").
Proposals have been made to use ultraviolet curing resins such as urethane (meth)acrylate, polyester (meth)acrylate, etc.

Among them, JP-A-60-181170 and JP-A-61-2653.
6, 61-291611, 62-30640, 6
2-30641 and 60-30642 contain urethane (
Coating materials that use meth)acrylate as the main component have been proposed, and in these proposals, in order to maintain a good balance between elongation and toughness of the cured product, polyol is Various ingredients have been studied.

However, in order to obtain long-lasting reliability as an optical fiber, it is necessary not only to ensure the primary balance between strength and elongation as described above, but also to satisfy various physical properties after secondary environmental tests. It has to be something. However, as mentioned above, with the curable materials proposed so far, various physical properties after secondary environmental tests, especially after long-term immersion in hot water (for example, 1-force immersion in 80°C hot water) The disadvantage was that the physical properties after immersion in the moon were poor.

In addition, a high refractive index is required for the so-called primary coat that is applied immediately after wire drawing as a protective coating material, but the curable materials proposed so far as mentioned above do not have a high refractive index. The refractive index was not sufficient, and there was a desire for an ultraviolet curable resin with an even higher refractive index.

[What does invention try to solve? Ja〕

In view of the current state of the art as described above, an object of the present invention is to provide a composition useful as an optical fiber protective coating, which has excellent physical properties and a high refractive index, especially after long-term immersion in hot water.

[Means to solve the problem]

It has been discovered that the above object can be achieved by using polyurethane poly(meth)acrylate containing a specific polyol component as the main material, leading to the completion of the present invention.

That is, the present invention provides (a) a polyurethane poly(
Provided is a coating composition for an optical fiber, comprising a meth)acrylate, (b) a compound having one or more polymerizable double bonds in one molecule, and (c) a photopolymerization initiator.

The polyurethane (meth) polyacrylate as the component (a) used in the present invention is composed of a halogenated bisphenol alkylene oxide adduct as a polyol component, a diisocyanate compound, and a hydroxyl group-containing (meth) polyacrylate.
Obtained by reacting with acrylate. The brominated bisphenol alkylene oxide adduct used as a polyol component has the following formula [■]: (R+, Rz are hydrogen or methyl groups, R3゜R4
is an alkylene group, and n is an integer from 1 to 1O). Specific examples of halogenated bisphenol-based alkylene oxide adducts include:
2,2-bis(3,5-dibromo-4(2-hydroxyethoxy)phenyl)propane, 2,2-bis[3,5
-dibromo-4(2-hydroxyethoxyethoxy)phenyl]propane, 2,2-bis[3,5-dibromo-
4(2-hydroxypropoxy)phenyl]propane,
Examples include 2,2-bis[3,5-dibromo-4(2-hydroxypropoxypropoxy)phenylpropane].

Examples of the diisocyanate compound to be reacted with the polyol component include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate,
Isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,
Examples thereof include 4'-diisocyanate, 1,6-hexane diisocyanate, diphenylmetal-4,4'-diisocyanate, and the like. Examples of the hydroxyl group-containing (meth)acrylate include compounds such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among them, dicyclohexylmethane-4,4'-diisocyanate is most preferred from the viewpoint of balance between strength and elongation.

As a method for synthesizing polyurethane poly(meth)acrylate (a) from the above raw materials, conventionally known synthesis methods can be employed. As for the reaction amount ratio of each component, the polyol component/diisocyanate compound ratio is 0.3.
/1.0 to 0.9/1.0, and the remaining isocyanate may be reacted with equimolar amount of hydroxyl group-containing (meth)acrylate. If the reactivity ratio is outside this range, the viscosity will become too high, resulting in poor workability, a large amount of bleed-out material after the 80°C hot water resistance test, and physical properties such as strength and elongation will deteriorate, which is undesirable. .

In the composition of the present invention, the compound (b) having one or more polymerizable double bonds in one molecule is blended to provide coating suitability. Specific examples of such compound (b) include tetrahydrofurfuryl (meth)acrylate, hydroxyphenyl (meth)acrylate, phenoxyethyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, and benzyl (meth)acrylate. ) acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, α-vinylpyrrolidone, tetrahydrofur Examples of the compound of furyl alcohol and ε-caprolactam adduct include a compound 2-ethylhexyl (meth)acrylate into which a (meth)acryloyl group has been introduced, and a compound represented by the following structural formula CI). Among these, a compound represented by the following structural formula (III) is most preferred from the viewpoint of balance of strength and elongation.

CHz=CH-CO-(OC2H4), -0-CH2
Cl(C211s)-(CH2):t-CH3(I[[
) (In the formula, n is 1 or 2.) In the composition of the present invention, polyurethane poly(meth)acrylate (a) and a compound (b) having one or more polymerizable double bonds in one molecule; The blending ratio is 30/70~95
15 (weight ratio). Outside of this range, the viscosity of the entire system increases, the coating suitability decreases, the number of bleed-outs after the 80° C. hot water resistance test increases, and physical properties such as strength and elongation decrease, which is not preferable.

Specific examples of photoinitiators used in the compositions of the invention include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, hesiphenone, xanthone, fluorenone, benzaldehyde, anthraquinone, 3-methylacetophenone, 4-chloro Benzophenone, 4,4'-diaminobenzophenone, benzoinpropyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1-(4-isopropylphenyl)
-2-hydroxy-2-methylpropan-1-one, 2
-Hydroxy-2-methyl-1-phenylpropane-1
-one, thioxanthone, camphorquinone, 2-methyl-1-(4(methylthio)phenyl)-2-morpholino-propan-1-one, and the like.

These photopolymerization initiators can be used alone or in combination of two or more in any proportion.

The amount used is usually from 0.1 to 10, based on the weight of the composition.
% by weight, preferably 1-5% by weight.

The composition of the present invention may further include a polymerizable monomer, for example, a polyfunctional (meth)acrylate such as polyethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. ) Acrylate compounds and compounds such as epoxy poly(meth)acrylates and polyester(meth)acrylates can be blended. Also,
If desired, modified resins such as epoxy resins, polyurethane resins, polybutadiene resins, and silicone resins, and additives such as silicone additives and fluorine additives can also be used.

〔Example〕

Hereinafter, the composition of the present invention will be specifically explained with reference to Examples. In the examples, parts mean parts by weight.

Example 1 264.8 g (1 mol) of dicyclohexylmethane-4,4'-diisocyanate and 30 g of polyethylene glycol (2-ethylhexyl) ether acrylate were placed in a 21-inch four-eye flask equipped with a stirrer, condenser, and thermometer.
7.1 g, 1.02 g of methyl ethyl hydroquinone as a polymerization inhibitor, and 0.20 g of dibutyltin dilaure as a catalyst, and the temperature inside the flask was set to 40°C.
After raising the temperature to , 576 g (0.8 mol) of 2,2-bis[3,5-dibromo-4(2-hydroxyethoxyethoxy)phenyl]propane was added to 100 g of polyethylene glycol (2-ethylhexyl) ether acrylate. 8. Drop the dissolved material from the dropping funnel and bring the internal temperature to 70.
After raising the temperature to 'C, the reaction was carried out for a total of 4 hours. Furthermore, 58.1 g of 2-hydroxyethyl acrylate (
0.5 mol) was added dropwise from the dropping funnel over 30 minutes, the temperature was further raised to 75°C, and the reaction was carried out until the NC0 value became 98% or more to obtain polyurethane polyacrylate. The amount of polyethylene glycol (2-ethylhexyl) ether 7 acrylate was 40% by weight of the total.

Next, 30 parts of polyethylene glycol ether acrylate as a diluent and 4 parts of 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one as a photopolymerization initiator were blended with 70 parts of the reaction product. ,
By mixing and dissolving, an optical fiber coating composition having a viscosity of 3040 CPS (25° C.) was obtained.

The resulting composition was spread 1. on a tin plate. Apply to a thickness of 0 mm, use two mercury lamps of 160 W/cm, conveyor speed of 5 m/min in one pass, reflector height of 10 cm.
It was cured by irradiating ultraviolet rays under the following conditions (cured film thickness: 0)
．． 211℃m). In order to evaluate the Shore hardness, strength elongation, refractive index, and hot water resistance of the resulting cured coating film, the strength elongation, weight range, and gel fraction were measured after 30 days in 80°C hot water.

The results are shown in Table I.

Example 2 By the same method as in Example 1, the polyol component was mixed with 2.
Polyurethane polyacrylate was synthesized in place of 2-bis[3,5-dibromo-4(2-hydroxypropoxy)phenyl]propane, and 30 parts of polyethylene glycol (2-ethylhexyl) ether acrylate was added to 70 parts of this reaction product as a diluent. and 1. as a photopolymerization initiator.
(4-isopropylphenyl)-2-hydroxy-2-
Four parts of methylpropan-1-one were blended and mixed and dissolved to obtain an optical fiber coating composition having a viscosity of 2480 CPS (25°C).

The coating composition was cured and evaluated in the same manner as in Example 1. The results are shown in Table I.

Example 3 Using the same method as in Example 1, using 2,2-bis[3,5-dibromo-4(2-hydroxyethoxyethoxy)phenyl]propane as the polyol component, the ratio (molar ratio) to isocyanate was determined. The reaction was carried out using isocyanate/polyol-1,0/0.4. Add 30 parts of polyethylene glycol (2-ethylhexyl) ether acrylate as a diluent to 70 parts of this reaction product '+yJ.
and 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1- as a photopolymerization initiator.
Blend 4 parts of On, mix and dissolve to obtain a viscosity of 1830 CPS (
25°C) was obtained.

The coating composition was cured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 By the same method as in Example 1, isocyanate was prepared using polytetramethylene glycol instead of 2,2-bis[3,5-dibromo-4(2-hydroxyethoxyethoxy)phenyl]propane as the polyol component. /polyol-1,010.5 (molar ratio) to synthesize polyurethane polyacrylate, and to 70 parts of the obtained reaction product, 30 parts of polyethylene glycol (2-ethylhexyl) ether acrylate as a diluent and 4 parts of 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one was blended as a photopolymerization initiator, mixed and dissolved to give a viscosity of 4850 CPS (
25° C.) was obtained.

The coating composition was cured and evaluated in the same manner as in Example 1. Show your results! Shown below.

Table-1 ml) Measuring wheel according to JIS K-7215 3) J
Measured according to IS K-7105 [Effect of the invention] The optical fiber coating composition of the present invention
There is little bleed-out even when immersed in hot water for a long time.
Moreover, there is no deterioration in strength and elongation performance. It also has a high refractive index. Therefore, it is excellent as a protective coating composition for optical fibers.

Claims (1)

[Claims] 1. (a) A polyurethane polyacrylate or polyurethane obtained by reacting a brominated bisphenol alkylene oxide adduct with a diisocyanate compound and a hydroxyl group-containing acrylate or a hydroxyl group-containing methacrylate as a polyol component. polymethacrylate, (b) a compound having one or more polymerizable double bonds in one molecule, and (c) a photopolymerization initiator, the (a)/(b) weight ratio being 30/70 to 95. /
5, and the amount of (c) is 0.1 to 1 based on the weight of the composition.
A coating composition for optical fiber, characterized in that the content is 0% by weight. 2. The optical fiber coating composition according to claim 1, wherein the component (b) is polyethylene glycol (2-ethylhexyl) ether acrylate. 3. The diisocyanate compound used for the preparation of component (a) is dicyclohexylmethane-4 represented by the following formula [I]
, 4'-diisocyanate. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼