JPS5835940B2 - Coating material for optical glass fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to coating materials for optical glass fibers.

Optical glass fibers (sometimes referred to as optical glass fibers) are easily damaged during manufacturing or storage, so the fiber surface is usually scratched several to several hundred μm in a continuous process immediately after fiber manufacturing. A method of coating with a polymeric material has been adopted.

Conventionally, thermosetting resins such as epoxy and urethane, or thermoplastic resins such as polyvinylidene fluoride and nylon have been used as coating materials, but it takes a long time to dry the coated material, and optical glass There are drawbacks such as poor adhesion between the fiber and the coating material, which slows down the production speed of the fiber and also poses problems in the reliability of the coated fiber.

In order to solve these drawbacks, the present invention uses a butadiene-based material as a coating material for optical glass fibers.The purpose of the present invention is to increase the manufacturing speed of optical glass fibers,
The object of the present invention is to obtain a coated optical glass fiber with high reliability.

In view of the above-mentioned drawbacks, the present inventors have studied various coating materials and found that, although the reason is not clear, the drying speed of butadiene-based materials is extremely fast, and the optical glass fiber coated with butadiene-based materials has a high strength. was found to be large and reliable.

The coating material of the present invention is composed of a two-component thermosetting resin, and its composition is a butadiene polymer (4
) and two or more hydroxyl groups, and the main skeleton consists of 1,2-butadiene bonds, or butadiene polymers, which have two or more carboxyl groups and the main skeleton consists of 1,2-butadiene bonds, or hydroxyl groups. , one or more butadiene selected from the group of butadiene polymers (B) having a functional group such as a carboxyl group, the number of functional groups is two or more, and a main skeleton consisting of a 1,2-butadiene bond. It is a mixture with polymer.

The butadiene polymer having a functional group in the present invention is obtained by addition reaction of butadiene, so-called living polymerization.

This reaction is carried out by replacing the inside of the reaction vessel with an inert gas, and gradually adding butadiene to a mixture of a Lewis base, an activator, and an alkali metal dispersion at a low temperature (for example, -80°C) with stirring. A living polybutadiene solution is produced.

Electrophilic reagents such as carbon dioxide (CO2), oxygen, and formaldehyde (H-CHO) are added to this living polybutadiene solution.

By reacting with a drug, a functional group can be introduced into the anionic end of the living polymer.

For example, a hydroxy group, methylol group, 2-hydroxyethyl group, 2-hydroxypropyl group, dithiocarboxyl group, etc. can be introduced at the end of the polymer chain.

After termination of the polymerization reaction, the diluent, Lewis space and other reagents added in excess are removed from the mixture by distillation.

By further performing separation and purification, a 1.2-addition polybutadiene derivative having a narrow degree of polymerization distribution can be obtained.

The butadiene polymer having a hydroxyl group at the terminal used in this invention is synthesized as follows.

The inside of the reaction vessel equipped with an airtight stirrer, a reflux condenser, a gas inlet pipe, an addition inlet, and a thermometer is replaced with nitrogen gas.

Metallic sodium finely dispersed therein contains orthoterphenyl (0-terphenyl).

Butadiene is gradually added to a system containing 1.2-diphenylbenzene dissolved in tetrahydrofuran at -80°C.

Adding the ethylene oxide immediately after adding the butadiene results in a gel-like semi-solid, giving a brown-brown mixture.

Further, water is added thereto and stirred, and the reaction solution is allowed to stand at room temperature to separate the layers.

Then remove the aqueous layer. Tetrahydrofuran and unreacted butadiene are distilled off from the solvent layer to obtain a liquid having a viscosity of 6000 centihoise (CP) at 45°C.

The number average molecular weight of this product was determined to be 1390 by osmotic pressure measurement.

The hydroxyl value was 68.3 ■KOH/9, and the components were in weight ratio.

The carboxyl group-containing butadiene polymer used in the present invention is synthesized as follows.

After purging the inside of the reaction vessel equipped with an airtight stirrer, reflux condenser, gas inlet tube, and addition/introduction ratio thermometer with nitrogen gas, finely dispersed metal (IJ) was added to tetrahydrofuran with naphthalene dissolved in it. Add, cool to -80℃,
Gradually add butadiene to this.

This reaction solution is poured onto solid carbon dioxide (so-called dry ice) and hydrolyzed.

By separating and purifying the reaction solution, a butadiene compound having a carboxyl group was obtained as a residue.

The number average molecular weight (Inago) determined by permeation pressure method was 1540, the acid value was 554 (■KOH/g), and the viscosity at 45°C was 19,000 CP.

Its components are carbon-carbon double bonds in weight ratio: 1.2 bonds 9
It was 1.5 ratio, 1.4 transformer coupling 8.5 ratio.

The modified product of the butadiene compound having a hydroxyl group used in the present invention with an incyanate group has a 1,2-
A polybutadiene urethane polymer and a 1,2 addition polybutadiene urethane polymer containing terminal free isocyanate groups are obtained.

For example, the weight ratio is 1.2 addition polybutadiene diol 4
Add 97 parts of tolylene diisocyanate to 19 parts,
Stir at 0°C.

As a result, 515 parts of a butadiene compound having a free incyanate group at the end was obtained.

This product had 4 isocyanate residues and a number average molecular weight (Mn) of 1,670.

A butadiene compound having a hydroxyl group and a carboxyl group can be obtained as follows.

1.2-diphenylbenzene (0-terphenyl
) was dissolved.

A polymerization reaction solution produced by adding butadiene to a system in which a sodium dispersion is added to tetrahydrofuran is treated with ethylene oxide.

The obtained butadiene compound having a hydroxyl group was introduced into a reaction vessel together with benzyl peroxide, dry air was introduced into the reaction vessel, and the mixture was reacted at 150°C.

Acid value 7 (■KOH/g), hydroxyl value 60 (immediately KOH/
A viscous product of g) was obtained.

As a result of measuring the infrared absorption spectrum of this material, carbon-
In addition to carbon double bonds, carbonyl groups, carboxyl groups,
/”f Droxyl ester bond absorption was observed.

The coating material used in the present invention is prepared by dissolving the 1.2 addition polybutadiene modified product in an appropriate organic solvent.

As the organic solvent, acetic acid esters such as butyl acetate and ethyl acetate, aromatic solvents such as toluene, xylene, and cresol, and in some cases, cyclohexane are used.

In addition, the molar ratio of the incyanate-modified butadiene compound and the butadiene compound having a hydroxyl group is -NCO/-O
When H is set to 1, gel ratio etc. tend to occur, so usually -NC
Optimal is O/-OH around 1.1.

The coating material used in this invention is a modified butadiene polymer and contains double bonds.

Therefore, it is also effective to use a hardening agent such as cobalt naphthenate or lead naphthenate to accelerate hardening.

In addition, in order to improve the adhesion between the coating material and the optical fiber,
It is also possible to add and use a silane coupling agent such as γ-methacroxypropyltrimethoxysilane, vinyltrimethoxy*silane, and β-epoxycyclohexylethyltrimethoxysilane.

The general formula of a typical butadiene polymer used in the present invention is as follows.

Butadiene polymers containing hydroxyl groups Butadiene polymers containing carboxyl groups Butadiene polymers containing incyanate groups In the present invention, the functional groups that react with isocyanate groups and contribute to crosslinking are hydroxyl groups and carboxyl groups.

Further, although esters, carbonyl groups, etc. do not contribute to the crosslinking reaction, it is recognized that the drying properties of the film are improved.

The coating material in the present invention is characterized by a fast curing speed.

The figure shows the curing time of epoxy resins and urethane resins currently used as coating materials and the coating material of the present invention.

The horizontal axis represents time, and the vertical axis represents viscosity as a measure of the degree of curing.

Curve I shows the butadiene polymer of the present invention, curve (2) shows a conventional epoxy resin, and curve (2) shows a conventional urethane resin.

From this figure, it is recognized that the curing time of the present invention is short.

The composition of the materials used in this figure is as follows.

The butadiene polymer of the present invention is obtained by dissolving 50 parts of the resin in xylene-butyl acetate, and the mixing ratio is -NCO/-0.
An isocyanate-modified butadiene polymer with H=1.1 and NCO coefficient=4.0, and hydroxylation (■KOH/g)=9. z, acid value (■KOH/9)=]
It is a mixture of 2 hydroxyl group-modified and carboxyl group-modified butadiene polymers.

As the epoxy resin, 100 parts (by weight) of bisphenol A type epoxy resin (trade name Epicote 828), and as a hardening agent, ethylmethylimidazole (EMI) was used.
As the urethane resin, m-cresol is used as the solvent, the resin amount is 50 parts, the mixing ratio -NCO/-0H = 1.1, and the phenol block type isocyanate (trade name) with NC04 = 12. Death module A
P stable) and a polyol of 0H4=8.8 (trade name Desmofene 600).

The thus obtained coating material of the present invention is applied to an optical glass fiber immediately after production, and then cured by an appropriate method to obtain a coated optical glass fiber.

Note that even if an appropriate additive is added to the above-mentioned two-component thermosetting resin, it can be similarly used as a coating material for optical glass fibers.

Examples will be described below.

Example 1 The inside of a reaction vessel equipped with an airtight stirrer, a reflux condenser, a gas inlet pipe, an addition inlet, and a thermometer is replaced with nitrogen gas.

Butadiene is gradually added at -80 DEG C. to a system in which a solution of orthoterphenyl (1,2-diphenylbenzene) dissolved in tetrahydrofuran is added to finely dispersed metallic sodium.

Adding the ethylene oxide immediately after adding the butadiene results in a gel-like semi-solid, giving a brown-brown mixture.

Further, water is added thereto and stirred, and the reaction solution is allowed to stand at room temperature to separate the layers.

Then remove the aqueous layer. Tetrahydrofuran and unreacted butadiene are distilled off from the solvent layer to obtain a liquid having a viscosity of 6000 centipoise (cp) at 45°C.

The number average molecular weight of this product was determined to be 1390 by osmotic pressure measurement.

The hydroxyl value is 68.3 ■KOH/g, and its components are 1.2 carbon carbon double bonds 93.7% 1.4 by weight
Trans bond carbon carbon bond 5.1 ratio 1.4 cis bond carbon carbon bond 1.2 ratio.

97 parts of tolylene diisocyanate are added to 400 parts of the butadiene polymer having hydroxyl groups thus obtained, and the mixture is stirred at 80°C.

As a result, a butadiene polymer (4) having free isocyanate groups at the ends was obtained.

This product had an incyanate residue of 5.3 and a number average molecular weight (deposition τ) of 1,670.

Next, 1,2-diphenylbenzene (0-terp-h
A polymerization reaction solution produced by adding butadiene to a system in which a sodium dispersion is added to tetrahydrofuran in which enyl) is dissolved is treated with ethylene oxide.

The obtained butadiene compound having a hydroxyl group was placed in a reaction vessel together with benzyl peroxide, dry air was introduced into the reaction vessel, and the reaction was carried out at 150°C.

Acid value 7 (■KOH/g), hydroxyl value 60 (■KOH/f
! A viscous product (B1) of > was obtained.

As a result of measuring the infrared absorption spectrum of this material, carbon-
In addition to carbon double bonds, carbonyl groups, carboxyl groups,
Absorption of hydroxyl groups, carboxylic acids, and ester bonds was observed.

A coating material consisting of A and B and a mixed solvent of butyl acetate and xylene (resin concentration: 50% by weight) was applied to 100 m
The coating was applied to an optical glass fiber manufactured at a speed of 1 minute, and then dried and cured in a drying oven at 180° C. to obtain a coated optical fiber.

The surface of the fiber thus obtained was completely hardened, and no change was observed even after one hour of boiling water treatment.

Also, the average strength of this fiber is 480)c! 9/book d
Met.

Example 2 Using a method similar to B1 shown in Example 1, an acid value of 6.2 (■
A coating material consisting of a mixture of A used in Example 1 and butadiene polymer B2 containing a hydroxyl group (KOH/, 9), hydroxyl group 55 (■KOH), and a carboxyl group was used.

The coating material was applied to an optical glass fiber manufactured at a speed of 80 m/min, and then cured in a drying oven at 180° C. to obtain a coated optical fiber.

The surface of the coated optical fiber was completely cured, and there was no change even after one hour of boiling water treatment.

The average strength of this fiber was 512 kg/ma.

Example 3 The inside of a reaction vessel equipped with an airtight stirrer, a reflux condenser, a gas inlet pipe, an addition inlet, and a thermometer is replaced with nitrogen gas.

Metallic sodium finely dispersed therein contains orthoterphenyl (0-terphenyl).

Butadiene is gradually added to a system containing 1.2-diphenylbenzene dissolved in tetrahydrofuran at -80°C.

Immediately after adding butadiene, ethylene oxide is added to form a gel-like semi-solid, resulting in a brown mixture.

Further, water is added thereto and stirred, and the reaction solution is allowed to stand at room temperature to separate the layers.

Then remove the aqueous layer. Tetrahydrofuran and unreacted butadiene are distilled off from the solvent layer to obtain a liquid having a viscosity of 6000 centipoise (CP) at 45°C.

The number average molecular weight of this product was determined to be 1390 by osmotic pressure measurement.

The hydroxyl value is 68.3 KOR/g, and its components are 1.2 carbon carbon double bonds 93.7% 1.4 by weight
Trans bond carbon carbon bond Section 5.1 1.4 Cis bond carbon carbon bond Section 1.2 A mixture of the hydroxyl group-containing butadiene polymer (B3) thus obtained and A used in Example 1 70 coating materials to avoid
After coating on the optical fiber manufactured at a speed of 1 m7 min, 1
It was cured in a drying oven at 80°C to obtain a coated optical fiber.

The surface of the coated optical fiber was completely cured, and there was no change even after one hour of boiling water treatment.

Comparative Example 1 A urethane resin consisting of Desmodur AP Stable as an isocyanate component and Desmofene 600 as a polyol component was applied to the surface of an optical glass fiber manufactured at a speed of 25 m/min, and then dried in a drying oven at 210'C. A coated optical glass fiber was obtained.

Although the surface of the fiber was dry, whitening was observed after one hour of boiling water treatment.

The average strength of this fiber was 283 kg/mtA.

As explained above, the optical fiber coating material of the present invention requires less time to dry than conventional coating materials, so it is possible to significantly increase the manufacturing speed of optical glass fibers, and the resulting It has the advantage of high fiber strength and high reliability.

[Brief explanation of the drawing]

The figure shows the curing time of the conventional coating material and the coating material of the present invention. ■・・・Polybutadiene polymer of the present invention, ■・・・
...Conventional epoxy resin, ■...Conventional urethane resin.

Claims (1)

[Claims] 1. A butadiene polymer having two or more isocyanate groups and having a main skeleton of 1,2-butadiene bonds, and a butadiene polymer having two or more hydroxyl groups and having a main skeleton of 1,2-butadiene bonds, or two. A butadiene polymer having the above carboxyl groups and whose main skeleton is composed of 1,2-butadiene bonds, or which has functional groups such as hydroxyl groups and carboxyl groups, and has two or more functional groups and whose main skeleton is 1.
．． A coating material for an optical fiber, characterized in that it is a two-component thermosetting resin comprising a mixture with one or more butadiene polymers selected from the group of butadiene polymers comprising 2-butadiene bonds.