JPS632834A - Primary coating material for optical glass fiber - Google Patents

Abstract

PURPOSE:To obtain the title resinous composition capable of providing a film capable of maintaining a low Young' modulus at low temp. by composing the composition essentially of epoxy acrylate obtained by the reaction of acrylic acid with a specified epoxy compd. of polyether polyol. CONSTITUTION:Epihalohydrin is allowed to react with the polyether polyol shown by HO(RO)nH [where R is a 2-4C alkylene group and (n) is 6-80] such as a copolymer of 10-80mol% ethylene oxide and 90-20% propylene oxide, polypropylene glycol, polyisobutylene glycol, polytetramethylene glycol, etc., to obtain halohydrin ether. The material is dehydrohalogenated to obtain the epoxy compd. of polyether polyol having 250-2,000 epoxy equivalents. Acylic acid is allowed to react with the epoxy compd. to obtain epoxy acrylate. The acrylate is used as the essential component, an acrylic monomer or resin compatible with the acrylate and a photopolymerization initiator are added in appropriate amts., and the primary coating material for optical glass fiber is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin composition for subsequent coating of optical glass fibers for light transmission, which provides a coating that can maintain a low Young's modulus at low temperatures by curing with ultraviolet light. It is something.

[Prior art]

The coating of optical glass fibers (hereinafter referred to as optical fibers) used for light transmission usually consists of two layers, an inner layer made of a low Young's modulus material and an outer layer made of a high Young's modulus material. This is called the next covering.

The primary coating reduces transmission loss and maintains initial strength.
The surface of the optical fiber is coated immediately after it is spun from a glass base material, and thermosetting silicone resin has conventionally been used as the primary coating material (Electronics Letters, Vol. 16, p. 100 (1980)) .

Recently, there has been a need to reduce the cost of optical fibers, which are transmission media, and various primary coating materials using UV-curable resins such as polybutadiene acrylate and polyester urethane acrylate, which are low-cost and can be manufactured at high speed, have been investigated. (Japanese Unexamined Patent Publication No. 58-223638).

[Problem that the invention seeks to solve]

These ultraviolet curable secondary coating materials have a higher Young's modulus at low temperatures than thermosetting silicone resins, and therefore have the drawback of increasing compressive strain due to shrinkage at low temperatures and increasing transmission loss.

[Specific means to solve the problem of luck]

An object of the present invention is to provide a resin composition for the primary coating of optical fibers that is cured by ultraviolet light and provides a film that maintains a low Young's modulus at low temperatures.

That is, the present invention provides epihalohydrin to a polyether polyol represented by the general formula HO(RO)nH [wherein R is an alkylene group having 2 to 4 carbon atoms, and n is a number from 6 to 80]. A primary coating for optical glass fibers whose main material is epoxy acrylate obtained by reacting acrylic acid with the epoxy compound of a polyether polyol obtained by reacting halohydrin ether and dehydrohalogenating this. It provides materials.

(Epoxy compound of polyether polyol) Epoxidized polyol, which is a raw material for epoxy acrylate, is a polyether obtained by reacting 10 to 80 mol% of ethylene oxide (EO) and 90 to 20 mol% of propylene oxide (PO). Polyol (either block copolymer or random copolymer) or polypropylene glycol is reacted with epihalohydrin in the presence of a Lewis acid, and the resulting halohydrin intermediate product is dehydrohalogenated with an alkali metal hydroxide. The epoxy equivalent is 250 to 2,0.
00 is desirable. If the epoxy equivalent is smaller than 250, the Young's modulus of the ultraviolet-cured epoxy acrylate product at low temperatures increases, which adversely affects the transmission loss of the optical fiber.

Moreover, when the epoxy equivalent is larger than 2000, the ultraviolet curability of the epoxy acrylate decreases, resulting in low productivity.

(Epoxy acrylate) Epoxy acrylate is produced by reacting the epoxy compound of the polyol with acrylic acid at a reaction temperature of 80 to 110°C for 50 minutes.
Paper synthesis can be performed by reacting for ~20 hours.

In this synthesis, acrylic acid is added in an amount of 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0.
It is desirable to select the blending ratio so that the amount is 2 moles.

In the above reaction, a catalyst, an inhibitor, etc. may be used as necessary, and examples of the catalyst include penzyltriethylammonium chlorite, benzyltributylammonium chloride, tetramethylammonium chloride,
Examples of the inhibitor include quaternary ammonium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and tetramethylammonium hydroxide. Examples of the inhibitor include hydroquinone, halodroquinone monomethyl ether, and phenothiazine.

The primary coating material for optical fibers based on epoxy acrylate of the present invention is well cured by various types of radiation, such as β rays, electron beams, and ultraviolet rays, but is particularly excellent in curing by ultraviolet rays.

In the case of curing with ultraviolet rays, use pentuin methyl ether, benzoin ethyl ether, benzoin isoglobyl ether, benzoin butyl ether, jetoxyacetophenone, benzyl dimethyl ketal,
2-Hydroxy-2-methylpropiophenone, 1-hydroxyschiff-4hexylphenylketone, benzophenone, Michler's ketone, N,N-dimethylamino-isoamyl benzoate, 2-chlorothioxanthone, 2,4-
Diethylteoxanthone and the like are preferably used, and at least one of these is usually added in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on the epoxy acrylate.

Epoxy acrylate, which is the primary coating material of the present invention, can be used alone, but in order to adjust the viscosity, it can also be used in combination with an acrylic monomer or resin whose Young's modulus changes little with temperature during curing.

Particularly preferred as the acrylic monomer or resin are monomers and oligomers having an ether bond in the molecule.

Specifically, ■2-methoxyethyl acrylate, 2-
Ethoxyethyl acrylate, 2-butoxyethyl acrylate, phenoxyethyl acrylate, phenyldiethylene glycol acrylate, phenyltriethylene glycol acrylate, phenyltetraethylene glycol ac! 7L/-), monomers such as /nylphenoxyethyl acrylate, nonylphenoxydiederene glycol acrylate, nonylphenoxytriethylene glycol acrylate; ■(a), 11 to 80 mol% of ethylene oxide (EO) and propylene oxide PO) 9? A polyether polyol having a molecular weight of 2.000 to 6,000 obtained by reacting with 20 Morph o, (b), a polyisocyanate, and (c).

Examples include acrylic resins such as urethane acrylates obtained by reacting with acrylates having hydroxyl groups.

The (&) polyether polyol, which is the raw material for the urethane acrylate mentioned above, has a molar ratio of ethylene oxide to propylene oxide (EO/PO) of 8/2 to
Either a block copolymer or a random copolymer of 1/9 ethylene oxide and propylene oxide can be used. The number of molecules of this polyether polyol is 2
．． 000 to 6°000. When the molecular weight is less than 2.000, the ultraviolet cured product of the photocurable resin composition tends to have a large Young's modulus at low temperatures, and the optical fiber is likely to be damaged. Moreover, when the molecular weight is larger than 6,000, the ultraviolet curability of the photocurable resin composition decreases, resulting in low productivity.

Next, as the Φ) polyisocyanate, 2.4-tolylene diisocyanate, 2.6-)lylene diisocyanate, diphenylmethane-4,4'-diisocyanate, naphthylene-1,5-diisocyanate, xylylene diisocyanate, inhorn diisocyanate, 1,
Included are 6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and mixtures thereof.

Next, (c) acrylates having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and mixtures thereof.

This urethane acrylate has a molar ratio of (a)/(b) of polyether polyol (a), polyinsyanate (b), and acrylate (c) having hydroxyl groups.
/(e), then these raw materials are a/e-=0.5~2
Synthesized by using and reacting at a ratio of (za+c)/zb=i to 1.2.

As a method for synthesizing urethane acrylate, (1) a method in which a polyether polyol and a polyisocyanate are reacted, and then an acrylate having a hydroxyl group is reacted. (
2) A method in which a polyincyanate and an acrylate having a hydroxyl group are reacted and then a polyether polyol is reacted, and (3) a method in which a polyether polyol, a polyisocyanate, and an acrylate having a hydroxyl group are simultaneously reacted, and the temperature is 50 to 110°C. 1 as necessary
React for ~20 hours.

During the reaction, for example, 1,4-diazabicyclo(2,2
, 2) An isocyanate reaction catalyst such as octane, tin octoate, and dibutyltin dilaurate, and an acryloyl group polymerization inhibitor such as hydroquinone, nihydroquinone monomethyl ether, and phenothiazine may be added.

The urethane acrylate thus obtained is represented by the following formula.

[In the formula, R3 is an alkylene group of an acrylate having a hydroxyl group, & is a group of a polyincyanate in which an incyanate group is left, and Rs is a group of a polyether polyol without a hydroxyl group. R is H or CH3] The ratio of these acrylic monomers 7 or acrylic resins to the epoxy acrylate is usually 1 to 1.
80% by weight, preferably 10-50% by weight.

Therefore, the primary coating material for optical glass fibers of the present invention includes, for example, (1) 60 to 100% by weight of epoxy acrylate a3), an acrylic monomer compatible with component (A) above, and 40 to 0% by weight of the above resin. (A)
Even if it is indicated that it is a photopolymerizable resin composition containing 0.1 to 10 parts by weight of a photopolymerization initiator to 100 parts by weight of the photocurable resin containing component (B) and (B), good.

The mechanical properties of a product cured by ultraviolet rays basically depend on the epoxy acrylate as component (A) or the epoxy acrylate and the urethane acrylate as component 03). 4
It is mainly used to lower the viscosity of the cured product to make it easier to coat the optical fiber with the photocurable resin composition without increasing the Young's modulus of the cured product at 0°C. For this reason, it is preferable that the blending ratio of the acrylic monomer (iii) is 40% by weight or less of the resin content in the secondary coating material.

In addition to the above-mentioned components, the resin composition for subsequent coating of optical fibers of the present invention contains thermal polymerization inhibitors (), hydroquinone, hydroquinone monomethyl ether, benzoquinone, and catechol, if necessary, for the purpose of inhibiting polymerization due to heat during storage. , pt-butylcatechol, phenothiazine, etc.)
, even if various additives such as thermoplastic resins (polyurethane resins, polyester resins, acrylic resins, silicone resins), organosilicon compounds, and surfactants are added to this composition to improve the physical properties of the coating film. good.

In order to actually coat an optical fiber using the optical fiber-subsequent coating resin composition of this invention, a conventionally known method (
It can be carried out according to Japanese Patent Application Laid-Open No. 58-22638, DT2.459,320), and after applying the resin composition for primary coating of the present invention on the surface of an optical fiber, it can be polymerized and cured by irradiating it with ultraviolet rays. good.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts in the examples are based on weight unless otherwise noted.

Example 1 Epoxidized polyether polyol with a molecular weight of 2,000, which is a block copolymer of ethylene oxide (10 mol%) and topropylene oxide (90 mol%)
Epoxy equivalent: 1,200) 93.8 parts, 6.2 parts of acrylic acid, 0.5 part of benzyltriethylammonium chloride, and 0.0 parts of hydroquinone monomethyl ether.
．． Epoxy acrylate was obtained by reacting at 110° C. for 10 hours in the presence of 0.5 parts.

100 parts of this epoxy acrylate was mixed with 3 m'1 of 1-hydroxycyclohexylphenyl ketone to obtain a primary coating material for optical fiber having a viscosity of 950 centivoids (25°C).

This coating material was applied to a glass plate to a thickness of 100μ, and a high-pressure mercury lamp with an output of 2.0 and an output density of soW/6R was installed perpendicular to the sample passing direction using an irradiation device, and a mortuary was placed at a position of 9α below the light source. The film was cured at a conveyor speed of 10 m/min. The physical properties of the obtained film are shown below.

Temperature Young's modulus (kg/d) *1+20℃
55 0°C 58 -20°C 65 -40°C 89 Hardness (Shore A) 69 *1: Hereinafter, Young's modulus is 2.5% modulus.

Optical fiber base material is drawn at a drawing speed of 30 m/min with a diameter of 125 mm.
After spinning into a μm optical fiber, the coating material was applied to the surface of the optical fiber in a process subsequent to the spinning process, and two high-pressure mercury lamps (output 2 wide, output density 80W10n) installed parallel to the drawing direction were used. It was cured by irradiating it with ultraviolet light.

The outer diameter of the optical fiber after coating was 250 μm, and the surface was uniform. The resulting coated optical fiber was kept at -40°C.
No increase in transmission loss was observed up to this point.

Example 2 Molecule 3 is a random copolymer of ethylene oxide (70 mol%) and topropylene oxide (30 mol%)
95.3 parts of epoxidized polyether polyol (epoxy equivalent: 1700) and 4.7 parts of acrylic acid were mixed with 0% tetramethylammonium bromide.
．． 5 parts and 0.05 parts of phenothiazine at 110°C.
By reacting for 12 hours, epoxy acrylate was obtained.

To 80 parts of this epoxy acrylate, a molecular weight of 1.000
10 parts of urethane acrylate obtained by reacting inphorone diisocyanate and hydroxyethyl acrylate, 10 parts of phenoxypolyethylene glycol acrylate, and 3 parts of 1-hydroxycyclohexylphenyl ketone were dissolved and mixed in polytetramethylene glycol of 2000 centipoise ( A primary coating material for optical fiber was obtained.

The physical properties of a cured film obtained using this coating material in the same manner as in Example 1 are shown below.

Temperature Young's modulus (try/d) +20°C 90 0°C 92 -20°C 99 -40°C 115 Hardness (Shore A) 80 Further, a coated optical fiber obtained in the same manner as in Example 1 using this coating material had the following properties: No increase in transmission loss was observed up to -40°C.

Example 3 85.5 parts of an epoxidized product of polypropylene glycol having a molecular weight of 700 (i/epoxy: 470), 14.5 parts of acrylic acid, 0.5 part of tetrabutylammonium bromide and 0.05 part of hydroquinone monomethyl ether By reacting at 110° C. for 8 hours in the presence of the above-mentioned epoxy acrylate, a paper-formed epoxy acrylate was obtained.

Ethylene oxide (10 mol%) and pumavilene oxide (90 mol%) were added to 75 parts of this epoxy acrylate.
25 parts of urethane acrylate obtained by reacting tolylene diisocyanate and hydroxyethyl acrylate and 3 parts of benzyl dimethyl ketal were dissolved and mixed in a polyether polyol having a molecular weight of 312,000, which is a block copolymer of ℃
) was obtained as a primary coating material for optical fiber.

The physical properties of the cured film obtained using this coating material in the same manner as in Example 1 are shown below.

Temperature Young's modulus (T/-) +20°C 75 0°C 77 -20°C 84 -40°C 98 Hardness (Shore A) 74 In addition, a coated optical fiber obtained in the same manner as in Example 1 using this coating material had the following properties: No increase in transmission loss was observed up to -40°C.

Example 4 Molecule ill, 91.6 parts of epoxidized polyisobutylene glycol of 500 (epoxy equivalent: 940) and 8.4 parts of acrylic acid in the presence of 0.5 part of benzyltriethylammonium chloride and 0.05 part of phenothiazine Epoxy acrylate was obtained by reacting at 110° C. for 15 hours.

3 parts of benzyl dimethyl ketal were dissolved and mixed in 100 parts of this epoxy acrylate to obtain a primary coating material for optical fiber having a viscosity of 1,700 centivoise (25°C).

The physical properties of a cured film obtained using this coating material in the same manner as in Example 1 are shown below.

Temperature Young's modulus (#/clI), +20℃
63 0°C 69 -20°C 74 -40°C 90 Hardness (Shore A) 72 In addition, the coated optical fiber obtained using this coating material in the same manner as in Example 1 showed no increase in transmission loss up to -40°C. I couldn't.

Example 5 90.0 parts of an epoxidized polytetramethylene glycol having a molecular weight of 1,000 (epoxy equivalent: 6 s O) and 10.0 parts of acrylic acid were mixed with 0.5 parts of tetramethylammonium chloride and 0 parts of hydroquinone monomethyl ether. Epoxy acrylate was obtained from K by reacting at 110° C. for 12 hours in the presence of .05 parts.

Molecules in 70 parts of this epoxy acrylate! 2゜00 to
30 parts of urethane acrylate obtained by reacting tolylene diisocyanate and hydroxyethyl acrylate and 3 parts of 1-hydroxyethylhexylphenyl ketone were dissolved and mixed in polypropylene glycol of 0.0 to prepare a primary optical fiber having a viscosity of 8200 centiboise (25°C). A coating material was obtained.

The physical properties of a cured film obtained using this coating material in the same manner as in Example 1 are shown below.

Temperature Young's modulus (I) +20°C 46 0°C 52 -20°C 58 -40°C 74 Hardness (Shore A) 48 In addition, a coated optical fiber obtained using the present coating material in the same manner as in Example 1 No increase in transmission loss was observed up to -40C.

Claims (1)

[Claims] 1) A polyether polyol represented by the general formula HO(RO)_nH [wherein R is an alkylene group having 2 to 4 carbon atoms, and n is a number from 6 to 80] An optical glass fiber whose main material is epoxy acrylate obtained by reacting acrylic acid with the epoxy compound of a polyether polyol obtained by reacting epihalohydrin with epihalohydrin and dehydrohalogenating this to obtain a halohydrin ether. Primary coating material. 2) The polyether polyol is selected from a copolymer of 10 to 80 mol% of ethylene oxide and 90 to 20 mol% of propylene oxide, polypropylene glycol, polyisobutylene glycol, and polytetramethylene glycol. A primary coating material for optical glass fibers according to item 1. 3), the epoxy equivalent of the epoxy compound is 250 to 2,0
00. The primary coating material for optical glass fiber according to claim 1. 4) The primary coating material for optical glass fibers contains (A) 60-100% by weight of epoxy acrylate (B) 40-0% by weight of an acrylic monomer or resin compatible with component (A) above. Photocurable resin 1 containing component ) and component (B)
The optical glass fiber according to claim 1, which is a photopolymerizable resin composition containing a photopolymerization initiator in a ratio of 0.1 to 10 parts by weight to 0.00 parts by weight. Primary coating material. 5) The acrylic resin of component (B) contains (a) 10 to 80 mol% of ethylene oxide (EO).
and a polyether polyol with a molecular weight of 2,000 to 6,000 obtained by reacting 90 to 20 mol% of propylene oxide (PO), (b), a polyisocyanate, and (c), an acrylate having a hydroxyl group. The primary coating material for optical glass fibers according to claim 4, which is a urethane acrylate obtained by reaction.