JPH05229854A - Production of optical fiber having hard coated film - Google Patents

Abstract

PURPOSE:To improve surface hardness, scratch resistance, durability, etc., of the subject optical fiber by plating an optical fiber with a primer agent containing a liquid capable of dissolving or swelling a plastic clad and coating the plated optical fiber with a given coating agent. CONSTITUTION:A plastic clad (A) of an optical fiber consisting of a core and a plastic clad is obtained from a polymer as a main component comprising a vinylidene fluoride unit and/or a fluoroalkyl (meth)acrylate unit. One or more liquids capable of dissolving or swelling the component A are selected from ether-based solvents, ketone-based solvents, ester-based solvents, fluorine-based solvents and chlorine-based solvents and a primer agent (B) comprising >=50wt.% of the liquid is obtained. The component A is coated with the component B by immersion method, subjected to hot air drying and then coated with a hard coating material (C) of organopolysiloxane base to produce an optical fiber having a coating film with 0.1-200mum thickness of film of the component C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hard coat-coated optical fiber which is excellent in surface properties such as surface hardness and scratch resistance and has excellent durability.

[0002]

2. Description of the Related Art An optical fiber generally comprises a core through which light is transmitted, a clad having a lower refractive index than the core and covering the periphery of the core, and a coating layer (protective layer) further surrounding the clad. It consists of

When connecting the optical fiber, a complicated manual operation of peeling a coating layer of polyvinyl chloride, polyethylene or the like, inserting it into a connector (coupler), and connecting it is performed. It is very easy to damage the optical fiber during such a connecting operation. In particular, in an optical fiber in which the clad material is made of plastic, the clad material has low surface hardness and scratch resistance, and the layer is very thin, so that the scratches that occur during the connection work easily reach the core. Light leakage easily occurs. Therefore, scratches during this operation have been a major problem as a cause of transmission loss.

Depending on the application, there is a case where an optical fiber having only a core and a clad without a coating layer is used. In this case, since the clad is exposed, it is easily damaged. There was such a problem.

In order to overcome such drawbacks, it has been proposed in JP-A-62-124040 that it is effective to provide a hard coat film on the clad.

[0006]

However, since the hard coat material proposed in this publication is an acrylic polymer, it is difficult to increase the surface hardness and scratch resistance of the optical fiber to a sufficient level. ..

Further, it is also desired that the hard coat film has excellent durability, because if the adhesion between the hard coat film and the clad is not sufficient, the hard coat film is easily peeled off due to bending of the optical fiber.

Therefore, the present invention can solve the above problems of an optical fiber having a plastic clad material and improve the surface performance such as surface hardness and scratch resistance of the optical fiber, and is excellent in durability. The main object is to provide a method for producing a hard coat-coated optical fiber capable of forming a hard coat film.

[0009]

In order to achieve this object, the present invention provides an optical fiber comprising a core and a plastic clad with a liquid capable of dissolving or swelling the clad (hereinafter referred to as a clad dissolving / swelling component). An optical fiber having a hard coat film is manufactured by pre-coating with a primer agent and then coating with an organopolysiloxane-based hard coat material.

For example, in the case of an optical fiber whose clad is mainly composed of a polymer containing a vinylidene fluoride unit and / or a fluoroalkyl (meth) acrylate unit, an ether type solvent, a ketone type solvent, an ester type clad dissolving and swelling component is used. One or more solvents selected from solvents, fluorine-based solvents, and chlorine-based solvents are used, and the content (solvent in the primer agent) is 50% by weight.
After precoating with the above primer agent,
An optical fiber having a hard coat film is manufactured by applying a coating treatment with an organopolysiloxane hard coat material.

The primer agent usually contains a non-volatile component such as a poly (meth) acrylate polymer in addition to the above-mentioned solvent.

In the optical fiber of the present invention, the core material may be glass or plastic as long as the clad material is made of plastic.

The material of the plastic clad material is
Vinyl fluoride, vinylidene fluoride, ethylene trifluoride,
Ethylene tetrafluoride, Propylene trifluoride, Propylene hexafluoride, Ethylene trifluoride chloride, Hexafluoroacetone; Ethyl trifluoride (meth) acrylate, Propyl tetrafluoride (meth) acrylate, Isopropyl hexafluoride (meth) Acrylate, pentyl (meth) acrylate octafluoride, isobutyl (meth) acrylate pentafluoride,
17 Fluoroalkyl (meth) acrylates such as dodecyl (meth) acrylate; α-fluoroacrylates such as methyl α-fluoroacrylate and ethyl trifluoride α-fluoroacrylate; perfluoro-2,2
A cyclic fluorinated olefin such as dimethyl-1,3-dioxole; or a polymer obtained by polymerizing one or more monomers having a low refractive index such as dimethylsiloxane and siloxanes such as trifluoropropylmethylsiloxane. However, other plastics may be used.

The above-mentioned fluorine-based polymer or silicone-based polymer is often used as the clad material of the optical fiber, but the polymer of these clad materials is inferior in adhesiveness to the organopolysiloxane-based hard coat material. Many.

Therefore, in order to overcome this problem, in the present invention, the surface of the clad is pre-coated with a primer agent having a specific composition, and then an organopolysiloxane hard coat is applied.

This primer agent is composed of a non-volatile (residual) component and a volatile (solvent) component.

As the non-volatile component of the primer agent, a polymer having a poly (meth) acrylate derivative as a main component is used. Specifically, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, lauryl ( (Meth) acrylate, dodecyl (meth)
Acrylate, stearyl (meth) acrylate, 2-
Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxyoligoethylene glycol (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N, N-
Dimethylaminoethyl (meth) acrylate, N, N-
Various (meth) acrylate derivatives such as diethylaminoethyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, 1,4-butanediol Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth)
Acrylate, trimethylolpropane (di / tri)
One or more main components selected from various polyfunctional (meth) acrylate derivatives such as (meth) acrylate, pentaerythritol (di / tri / tetra) (meth) acrylate, oligoethylene glycol di (meth) acrylate The polymers mentioned above are listed.

The precoating treatment is carried out in order to enhance the adhesiveness between the organopolysiloxane hard coat material and the clad. The film (primer film) formed by this precoating treatment improves the adhesiveness with the clad. Being good is also important.

In order to obtain good adhesion between the clad and the primer film, it is important to select a solvent as a solvent component in the primer agent, that is, a liquid which dissolves or swells the clad is preferable. It is necessary to use it as the main component of the solvent.

The liquid for dissolving the clad as used herein means a liquid capable of dissolving 5% by weight or more of the clad material after dipping 5 g of the clad material in 100 g of the liquid at room temperature for 7 days. Further, the liquid for swelling the clad means a liquid capable of increasing the amount of the clad material by 3% by weight or more after immersing 5 g of the clad material in 100 g of the liquid at room temperature for 7 days.

Further, if the solvent component in the primer agent remains for a long time after the precoating treatment, the clad dissolution and swelling component penetrates into the deep part of the clad layer, which adversely affects the translucency of the optical fiber. There is also. Therefore, it is desirable that the solvent component of the primer agent be volatilized promptly after coating, and for that purpose, the boiling point of the material of the clad dissolution swelling component is preferably 150 ° C. or lower.

As a solvent for such a clad-dissolving and swelling component, when the clad material is mainly composed of a polymer containing a vinylidene fluoride unit and / or a fluoroalkyl (meth) acrylate unit, for example, tetrahydrofuran or diethyl ether. , Ether solvents such as dioxane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate; CFC 113, CFC 112,
Fluorine-based solvents such as trifluoromethyl-benzene, 1,3-bis-trifluoromethyl-benzene, hexafluoroisopropanol, hexafluoroacetone hydrate; methylene chloride, chloroform, carbon tetrachloride, trichloroethane, chlorobenzene, dichlorobenzene, etc. The chlorine-based solvent can be exemplified.

If desired, these solvents can be used as a mixed solvent of two or more kinds. It is preferable that the above-mentioned clad dissolution and swelling component accounts for 50% by weight or more, more preferably 70% by weight or more, in the primer agent solvent in order to sufficiently enhance the adhesiveness between the clad and the primer film.

As a method of applying the primer agent, a method used in a usual coating operation can be applied, for example, a dipping method, a flow coating method, a spin coating method, a brush coating method, a spray method, a roll method, a curtain flow method. Etc. are preferred.

The primer agent thus applied is generally solvent-removed at room temperature or by heat drying to form a primer film. The heating method may be hot air, infrared rays, or the like. The heating temperature should be determined by the heat resistance of the applied optical fiber and the primer composition used, but it is necessary that the heating temperature does not exceed the heat resistance of the clad agent of the optical fiber, Is room temperature to 200 ° C, more preferably room temperature to 1
It is carried out at 50 ° C. If the temperature is lower than this, the drying tends to be insufficient. When the temperature is higher than this, the heat resistance of the clad material of the optical fiber is often exceeded, and problems such as thermal decomposition and cracking of the primer film and yellowing are likely to occur.

The thickness of the primer film in the present invention is preferably 0.1 to 200 μm from the viewpoint of maintaining the adhesive strength. Particularly preferably, it is 0.4 to 100 μm.

The organopolysiloxane-based component that forms the organopolysiloxane-based hard coat film in the present invention is, for example, an organosilicon compound represented by the following general formula (I) and its hydrolyzate, and the following general formula ( It is represented by at least one organosilicon compound selected from the group consisting of organosilicon compounds represented by II) and hydrolysates thereof.

[0028]

[Chemical 1] ^{(Wherein, R 1, R 2, R} 3, R 4, R 5, R 6 is an organic group having 1 to 10 carbon atoms .X and Q is a hydrolyzable group .a, c, e is 0 or 1 respectively, b,
d and f are 0, 1 or 2, respectively. Y has 2 carbon atoms
~ 40 organic groups. ) First, the organosilicon compound represented by formula (I) and its hydrolyzate will be described.

In the formula represented by the general formula (I), R ¹ and R ² are organic groups having 1 to 10 carbon atoms, and specific examples thereof include methyl group, ethyl group, phenyl group, vinyl group and the like. Hydrocarbon group, chloropropyl group, halogenated hydrocarbon group such as 3,3,3-trifluoropropyl group, epoxy such as γ-glycidoxypropyl group, β- (3,4-epoxycyclohexyl) ethyl group (Meth) acryl group-containing organic groups such as group-containing organic groups, γ-methacryloxypropyl group, γ-acryloxypropyl group, and other organic groups having various substituents such as mercapto group, cyano group and amino group. Be done. R ¹ and R ² are the same kind,
It may be different.

X is not particularly limited as long as it is a hydrolyzable functional group, in other words, a silanol group is formed by a hydrolysis reaction. Specific examples thereof include methoxy group, ethoxy group and methoxyethoxy group. An alkoxy group such as, an acyloxy group such as an acetoxy group,
Examples thereof include halogeno groups such as chloro group and bromo group, aryloxy groups such as phenoxy group, and the like.

Further, when (a + b) is 2 or more, R ¹
At least one of R ² and R ² is preferably a reactive organic group such as an epoxy group-containing organic group or a (meth) acryloxy group-containing organic group from the viewpoint of improving the surface hardness.

Specific representative examples of these organosilicon compounds are methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltripropoxysilane, methyltributoxysilane, and ethyltributoxysilane. Methoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxy Silane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane,
3,3,3-trifluoropropyltrimethoxysilane,
γ-methacryloxypropyltrimethoxysilane, γ-
Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltrimethoxyethoxysilane, γ-mercaptopropyltriethoxysilane, N-β- (aminoethyl) -γ- Aminopropyltrimethoxysilane, β-cyanoethyltriethoxysilane, methyltriphenoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, α-glycid Xyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane,
β-glycidoxyethyltriethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ
-Glycidoxypropyltrimethoxyethoxysilane,
γ-glycidoxypropyltriphenoxysilane, α-
Glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ- Glycidoxybutyltriethoxysilane, δ
-Glycidoxybutyltrimethoxysilane, delta-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, (3,4
-Epoxycyclohexyl) methyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyl Tripropoxysilane, β
-(3,4-Epoxycyclohexyl) ethyltributoxysilane, β- (3,4-epoxycyclohexyl)
Ethyltrimethoxyethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriphenoxysilane,
γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ-
Trialkoxysilanes such as (3,4-epoxycyclohexyl) butyltriethoxysilane, triacyloxysilanes or triphenoxysilanes or hydrolysates thereof, and dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldi Ethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxy Silane, γ-mercaptopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methyl Ruvinyldimethoxysilane, methylvinyldiethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, α-glycidoxyethylmethyldimethoxysilane, α-glycidoxyethylmethyldiethoxysilane, β -Glycidoxyethylmethyldimethoxysilane,
β-glycidoxyethylmethyldiethoxysilane, α-
Glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldimethoxysilane, β-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxypropylmethyldibutoxysilane, γ-glycidoxypropylmethyldimethoxyethoxysilane, γ-glycidoxypropyl Methyldiphenoxysilane, γ-glycidoxypropylmethyldiacetoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylvinyldimethoxy Orchid, γ-glycidoxypropylvinyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, dialkoxysilanes such as γ-glycidoxypropylphenyldiethoxysilane, diphenoxysilane or diacyloxysilanes or hydration thereof. Degradation products are an example.

Next, the organosilicon compound represented by the general formula (II) and its hydrolyzate will be described.

In the general formula (II), R ³ , R ⁴ ,
R ⁵ and R ⁶ include R ¹ and R in the general formula (I).
An example similar to ² can be given. Further, as Q, the same examples as X can be given.

Y is an organic group having 2 to 40 carbon atoms. That is, Y is a functional group contained in the molecule through two Si atoms and a Si—C bond, and among the functional groups,
There is no problem even if foreign atoms other than carbon and hydrogen such as oxygen atom and nitrogen atom are contained. Furthermore, within the range of 2 to 40 carbon atoms, the organic group may be chain-like or cyclic, and there is no problem even if an oxygen atom or the like is present as an epoxy ring or the like. Alternatively, it is preferable in that it contributes as a functional group during curing.

As a concrete example,

[Chemical 2] And so on.

Among the organosilicon compounds represented by the above general formula (I) or (II), the use of organosilicon compounds containing an epoxy group or a glycidoxy group is particularly preferred for the purpose of imparting flexibility. Is. For the purpose of imparting weather resistance and water resistance, it is preferable to use organic silicon compounds containing a vinyl group, a methyl group, a phenyl group and the like. From the viewpoints of curing speed and ease of hydrolysis, X and Q are preferably an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group.

Among these organosilicon compounds, a hydrolyzate is preferable in order to lower the curing temperature and accelerate the curing.

The hydrolysis may be carried out by adding pure water or an acidic aqueous solution such as hydrochloric acid, acetic acid or sulfuric acid and stirring. The degree of hydrolysis may be performed by adjusting the amount of pure water or acidic aqueous solution added. At the time of hydrolysis, it is particularly preferable to add pure water or an acidic aqueous solution that is at least equimolar and at most 3 times the molar amount of X and Q in the general formula (I) or (II) from the viewpoint of promoting the curing. During the hydrolysis, alcohol or the like is generated, so it is possible to perform the hydrolysis without a solvent.However, the hydrolysis is performed after mixing the organic silicon compound and the solvent for the purpose of making the hydrolysis more uniform. It is also possible. It is also possible to remove an appropriate amount of alcohol after hydrolysis under heating and / or reduced pressure for use depending on the purpose, and to add an appropriate solvent after that.

Examples of these solvents include alcohols, esters, ethers, ketones, halogenated hydrocarbons, aromatic hydrocarbons such as toluene and xylene, and solvents such as N, N-dimethylformamide. Further, these solvents can be used as a mixed solvent of two or more kinds, if necessary. Further, depending on the purpose, it is possible to accelerate the hydrolysis reaction and further heat it to room temperature or higher in order to promote the reaction such as precondensation, or to lower the hydrolysis temperature to room temperature or lower in order to suppress precondensation. It is also possible.

Further, in order to improve the hardness of the hard coat film, it is preferable to use a particulate inorganic oxide in combination. The particulate inorganic oxide is not particularly limited as long as it does not impair transparency in a coating film state and achieves its purpose, but workability and a particularly preferable example from the viewpoint of imparting transparency. , A sol dispersed in a colloidal form. More specific examples include magnesium fluoride sol, silica sol, titanium oxide sol, cerium oxide sol, zirconia sol, antimony oxide sol, and alumina sol. The amount of particulate inorganic oxide added is
In order to show the effect more significantly, 5% by weight in the cured film
It is preferable that the content is not less than 80% by weight. That is, if it is less than 5% by weight, no obvious effect of addition is observed, and if it exceeds 80% by weight, adverse effects such as poor adhesion to the substrate, cracking of the coating film itself, and reduction of impact resistance are likely to occur.

As the finely divided inorganic oxide, those having an average particle diameter of 1 to 200 mμ are usually used, but those having an average particle diameter of 5 to 100 mμ are preferably used. When the average particle size exceeds 200 mμ, the transparency of the formed film is lowered and the turbidity becomes large, which makes it difficult to increase the film thickness. If it is less than 1 mμ, the stability is poor and the reproducibility is poor. Further, there is no problem even if various surfactants and amines are added to improve the dispersibility of the fine particles. Further, there is no problem in using two or more kinds of fine particle inorganic oxides in combination.

Further, various surfactants can be used in the coating composition for forming the organopolysiloxane type hard coat film in order to improve the flow at the time of application. Of these, a block or graft copolymer of dimethylpolysiloxane and alkylene oxide, and a fluorine-based surfactant are effective.

For the purpose of further improving the weather resistance, it is possible to add an ultraviolet absorber or an antioxidant as a method for improving heat deterioration resistance.

Further, various inorganic compounds and the like can be added to these coating compositions as long as the film performance is not significantly deteriorated. By using these additives together, various physical properties such as adhesion to a substrate, chemical resistance, surface hardness, durability, and dyeability can be further improved. Preferred examples of the inorganic material that can be added include metal alkoxides represented by the following general formula (III), and various chelate compounds and / or hydrolysates thereof.

M (OQ) _m (III) (wherein Q is an alkyl group, an acyl group or an alkoxyalkyl group. M is the same value as the charge number of the metal M. M
Is silicon, titanium, zircon, antimony, tantalum,
Examples include germanium and aluminum. ) When forming the organopolysiloxane-based hard coat film in the present invention, various curing agents can be used in combination for the purpose of accelerating curing, curing at low temperature and the like. As the curing agent, an ordinary curing agent used when curing various epoxy resins or various organic silicon resins may be used.

Specific examples of these curing agents include various organic acids and their acid anhydrides, nitrogen-containing organic compounds, various metal complex compounds or metal alkoxides, and organic carboxylates of alkali metals, carbonic acid. Examples include various salts such as salts, and radical polymerization initiators such as peroxides and azobisisobutyronitrile. These curing agents can be used as a mixture of two or more kinds.

Among these curing agents, an aluminum chelate compound represented by the following general formula (IV) is particularly preferable from the viewpoints of stability of the coating composition and prevention of coloration of the coating film after coating.

Al Y _r Z _(3-r) ... (IV) (wherein Y is OL (L is a lower alkyl group), Z
Is a ligand derived from a compound represented by the general formula M ¹ COCH ₂ COM ² (M ¹ and M ² are both lower alkyl groups), and a general formula M ³ COCH ₂ COOM ⁴ (M ³ , M
⁴ is at least one selected from ligands derived from compounds represented by lower alkyl groups), and r is 0, 1 or 2. Among the aluminum chelate compounds represented by the above general formula (IV), aluminum acetylacetonate, aluminum bisethylacetoacetate monoamine, from the viewpoints of solubility in the composition, stability, effect as a curing catalyst, and the like. Acetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, aluminum-di-iso-propoxide-monomethylacetoacetate and the like are particularly preferable. It is also possible to use a mixture of two or more thereof.

As a coating method, a method used in a usual coating operation can be applied. For example, a dipping method, a flow coating method, a spin coating method, a brush coating method, a spray method, a roll method, a curtain flow method and the like can be used. preferable.

The coating composition thus applied is generally cured by heating and drying. As a heating method, hot air or infrared rays can be used.
The heating temperature should be determined by the heat resistance of the applied optical fiber and the coating composition used, but it is necessary that the temperature does not exceed the heat resistance of the cladding agent of the optical fiber, Usually from room temperature to 200
C., more preferably 35 to 150.degree. C. is used. At temperatures lower than this, curing or drying tends to be insufficient,
Further, if the temperature is higher than this, the heat resistance of the cladding material of the optical fiber is often exceeded, and problems such as thermal decomposition of the hard coat film, generation of cracks, and yellowing are likely to occur.

The thickness of the organopolysiloxane type hard coat film in the present invention is preferably from 0.1 to 200 μm from the viewpoint of retention of adhesive strength, hardness, surface gloss and the like. Particularly preferably, it is 0.4 to 100 μm.

Furthermore, in order to further improve the adhesiveness and wettability between the optical fiber clad surface and the primer film, or between the primer film and the hard coat film, the primer film on the clad surface or after the primer treatment The surface may be subjected to various chemical and physical treatments. For example, the chemical treatment includes hot water immersion, redox treatment, acid or alkali treatment, and the physical treatment is preferably plasma treatment, corona discharge treatment, ultraviolet irradiation, or the like.

The optical fiber having the organopolysiloxane type hard coat film of the present invention is preferably protected by further providing a coating layer of vinyl chloride resin, polyethylene resin, epoxy resin or the like on the optical fiber.

The form of the optical fiber may be a normal single-core form, a multi-core form in which a large number of optical fibers are fused between clad layers, or a film form with a wide core portion.

[0056]

In the present invention, the hard coat film is an organopolysiloxane hard coat material, and
Before forming the hard coat film, it is important to pre-coat the optical fiber with a primer agent containing a specific solvent.

That is, by precoating with a primer agent containing a liquid that dissolves or swells the clad, even if the clad material is a material having poor adhesiveness such as a fluorine-based polymer, the primer film is well adhered onto the clad. Therefore, the adhesion durability of the organopolysiloxane-based hard coat film can be improved.

Furthermore, since the hard coat film is an organopolysiloxane hard coat material, the surface characteristics such as surface hardness and abrasion resistance can be sufficiently improved.

[0059]

EXAMPLES Examples will be described below.

Example 1 (1) Preparation of primer agent 10 g of polymethylmethacrylate [“Acrypet VH” (manufactured by Mitsubishi Rayon Co., Ltd.)] was dissolved in 290 g of an equal mixture of ethyl acetate and butyl acetate, This was used as a primer.

(2) Preparation of hard coating agent 176 g of γ-glycidoxypropyltrimethoxysilane
While stirring, control the liquid temperature to 10 ° C and
A hydrolyzate was obtained by dropwise mixing 40.3 g of a 5 N hydrochloric acid aqueous solution. To 51.8 g of this hydrolyzate, 18.3 g of ethanol, 183 g of n-propanol, 1.5 g of aluminum acetylacetonate and a silicone-based surfactant (“SR manufactured by Torre Dow Corning Silicone Co., Ltd.
X-294A ″) (0.15 g) was added, and the mixture was stirred until it became uniform to obtain a hard coat agent.

(3) Coating and Cure An optical fiber having a vinylidene fluoride / tetrafluoroethylene copolymer (copolymerization ratio: 80/20% by weight) as a clad material is coated with the primer agent prepared in the above (1). It was applied by the dipping method. The coated optical fiber was heat-treated with a hot air dryer at 60 ° C. for 1 hour. Next, the hard coating agent prepared in the above (2) was applied to the primed optical fiber by a dipping method. The coated optical fiber was heated and cured in a hot air dryer at 80 ° C. for 2 hours.

(4) Test Results The performance of the obtained optical fiber having a hard coat film was evaluated according to the following test method. The results are shown in Table 1.
As shown in, the appearance, scratch resistance, and durability were all excellent.

(B) Appearance The quality of the appearance was evaluated by observing the transparency, colorability, and presence of cracks with the naked eye.

(B) Scratch resistance of the coating The surface was rubbed with # 0000 steel wool to determine the scratch condition. The criterion was as follows.

Good: Scratches slightly occur when rubbed strongly.

Defect: Scratches occur even if rubbed weakly.

(C) Durability of coating film After the optical fiber was repeatedly bent and extended at 20 mmφ and 90 ° for 50 times, it was judged whether or not the coating film was peeled off with the naked eye to judge the durability of the coating film. did.

Example 2 (1) Preparation of primer agent 10 g of polymethylmethacrylate [“Acrypet VH” (manufactured by Mitsubishi Rayon Co., Ltd.)] was dissolved in 290 g of hexafluoroisopropanol, and this was used as a primer agent.

(2) Preparation of hard coat agent (a) 263.7 g of vinyltrimethoxysilane and 1 part of acetic acid
9.8g was added, while maintaining the liquid temperature at 10 ° C under stirring,
74.7 g of 0.05N hydrochloric acid was added dropwise to obtain a vinyltrimethoxysilane hydrolyzate.

(B) Methyltrimethoxysilane 378.
28.8 g of acetic acid was added to 0 g, and 149.4 g of 0.01N hydrochloric acid was added dropwise while maintaining the liquid temperature at 10 ° C. under stirring to obtain a methyltriethoxysilane hydrolyzate.

(C) 352.6 g of the vinyltriethoxysilane hydrolyzate obtained in (a) above and the methyltrimethoxysilane hydrolyzate 547.gm obtained in (b) above.
4 g with stirring, and further 2 g of sodium acetate, 80 g of xylene, 20 g of butyl acetate and a silicone surfactant [“SRX-298” (Toray Dow Corning.
(Manufactured by Silicone Co., Ltd.)] was added and stirred until uniform to obtain a hard coat agent.

(3) Coating and Cure The primer agent prepared in (1) above was applied to an optical fiber having a fluoroalkylmethacrylate copolymer as a cladding material by a dipping method. 60 coated optical fiber
It heat-processed for 1 hour with the hot air dryer of (degree C). Next, the hard coat agent prepared in the above (2) was applied to the primer-treated optical fiber by a dipping method. The coated optical fiber was heated and cured in a hot air dryer at 80 ° C. for 2 hours.

(4) Test Results A performance test of the obtained optical fiber having a coating film was carried out in the same manner as in Example 1. The results are, as shown in Table 1, excellent in appearance, scratch resistance and durability.

Comparative Example 1 The optical fiber used in Example 1 was subjected to the same test as Example 1 without coating anything. As a result, as shown in Table 1, scratch resistance was poor.

Comparative Example 2 In the same manner as in Example 1, except that 290 g of toluene was used in place of 290 g of an equal mixture of ethyl acetate and butyl acetate as a solvent for the primer agent, a primer treatment and a hard treatment were performed. An optical fiber having a hard coat film was obtained by coating. As shown in Table 1, the results of the test conducted in the same manner as in Example 1 were excellent in appearance and scratch resistance, but poor in durability.

Comparative Example 3 An optical fiber having a hard coat film was obtained in the same manner as in Example 1 except that the hard coat agent was applied without the primer treatment. As shown in Table 1, the results of the test conducted in the same manner as in Example 1 were excellent in appearance and scratch resistance, but poor in durability.

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[Table 1]

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According to the present invention, when a hard coat film is formed on the surface of a plastic clad material for an optical fiber, the surface performance such as surface hardness and scratch resistance of the optical fiber can be greatly improved. Moreover, since the hard coat coating and the clad have excellent peeling resistance, a hard coat coated optical fiber having excellent durability can be obtained.

Therefore, in the obtained coated optical fiber, the scratches on the surface and the peeling of the coating during the operation such as the connection work are greatly reduced, and the handling property and the durability during the operation are greatly improved.

Claims (3)

[Claims] 1. An optical fiber comprising a core and a plastic clad is precoated with a primer agent containing a liquid capable of dissolving or swelling the clad,
A method for producing an optical fiber having a hard coat film, which comprises coating with an organopolysiloxane hard coat material. 2. The plastic clad in the optical fiber is mainly composed of a polymer containing vinylidene fluoride units and / or fluoroalkyl (meth) acrylate units, and 50% by weight or more of the solvent in the primer agent. Is a liquid capable of dissolving or swelling the clad, and the liquid is one or more selected from ether solvents, ketone solvents, ester solvents, fluorine solvents and chlorine solvents. The method for producing an optical fiber having a hard coat film according to claim 1, which is a solvent. 3. The primer agent comprises a polymer containing a poly (meth) acrylate polymer as a main component, and a solvent containing a liquid capable of dissolving or swelling the clad as a main component. Item 2. A method for producing an optical fiber having a hard coat film according to Item 1.