JPH05112619A - Resin composition and plastic-clad optical fiber using the same - Google Patents

Abstract

PURPOSE:To obtain a resin composition, containing plural silicon atoms bound to plural alkoxy groups and a specific reactive compound, excellent in adhesive strength, etc., between a core and a clad and useful as optical fiber, etc. CONSTITUTION:The objective resin composition containing (A) >=2 silicon atoms bound to >=2 alkoxy groups and (B) a reactive compound such as N,N-bis [3-(methyldimethoxysilyl)propyl] (meth)acrylamide having at least one functional group (e.g. CH2=CHCO-) capable of forming chemical bond with an ultraviolet curing type resin such as an acrylate or methacrylate copolymer having unsaturated bond in the ester side chain. Furthermore, the amount of the component (B) is preferably 0.01-10 pts.wt. based on 100 pts.wt. resin composition. A cured product of the composition is preferred as a clad material in optical fiber using quartz-based or optical glass as a core and a plastic having a lower refractive index than that of the core as a clad.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic clad optical fiber having a resin composition and a cured product thereof as a clad.

[0002]

2. Description of the Related Art UV-curable fluorinated acrylate is preferable as a clad material for polymer clad optical fibers because the resin itself has excellent mechanical strength and low optical transmission loss. However, when the uncured resin is applied on the core glass and then cured by irradiation with ultraviolet rays, a gap is generated between the core and the clad due to curing shrinkage, which not only increases the transmission loss but also lowers the tensile strength of the optical fiber. .. Further, since the adhesive force between the core and the clad is low, it is not possible to obtain sufficient connector pull-out strength after attaching the connector.

Therefore, as a compound capable of forming a chemical bond between the core glass and the clad polymer at the time of ultraviolet curing, as shown in the following formula (I), one ultraviolet functional group and at least one alkoxy group are used. Alternatively, it is described in JP-A-64-24203 to attempt to solve the above problems by adding a compound having a halogen-bonded silicon atom in the same molecule to a clad-forming resin composition:

[Chemical 1] [In the formula, Z represents a functional group capable of forming a chemical bond with an ultraviolet curable resin by irradiation with ultraviolet rays, at least one of X _{1 to} X ₃ represents an alkoxy group or halogen, and the other groups represent an alkyl group or fluoroalkyl. Represents a group, and R represents a single bond or a divalent organic group connecting Z and Si. ].

[0004]

However, in the conventional technique, the adhesive force between the core and the clad after curing was insufficient. An object of the present invention is to provide a plastic clad optical fiber having a sufficiently high adhesive force between the core and the clad.

[0005]

The present invention comprises at least two aspects.
At least 2 silicon atoms bonded to one alkoxy group
And a reactive compound having at least one functional group capable of forming a chemical bond with an ultraviolet curable resin in the same molecule.

The present invention also provides a plastic clad optical fiber having a silica or optical glass as a core and a plastic having a refractive index lower than that of the core as a clad, wherein the clad material is a cured product of the resin composition. To do.

The resin composition of the present invention comprises a reactive compound and an ultraviolet curable resin. The resin composition of the present invention,
It is photocurable, especially UV curable. In the reactive compound, the alkoxy _group, -OCH 3, -OCH ₂ C
_{H 3, -OCH 2 CH 2 CH} 3, preferably -OCH ₂ CH ₂ OCH _3. Chlorine is preferable as the halogen. Further, as the functional group capable of forming a chemical bond with the ultraviolet curable resin, CH ₂ ═CHCO— and CH ₂ ═C (CH ₃ ) CO.
_{-, CH 2 = C (CF} 3) CO-, CF 2 = C (CF 3) CO
-, CH ₂ = CH- or I- are preferable.

Examples of reactive compounds include N, N-bis
[3- (Methyldimethoxysilyl) propyl] (meth) acrylamide, N, N-bis [3- (trimethoxysilyl) propyl] (meth) acrylamide, and formula:

[Chemical 2] [In the formula, R ¹ is hydrogen or a methyl group, Rx is a hydrocarbon group having an unsaturated bond in the molecule, Rf is a fluoroalkyl group, R is hydrogen, a methyl group, an ethyl group or a propyl group, and Z is a single group. A bond or an organic group consisting of carbon, hydrogen and oxygen, x represents a number of 1 to 1000, y represents a number of 2 to 1000, and w represents a number of 0 to 1000. ] The (meth) acrylate type polymer shown by these can be mentioned.

The group Z consisting of carbon, hydrogen and oxygen is

[Chemical 3] (m and n are integers from 1 to 10). The amount of the reactive compound is usually 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin composition.

Examples of UV-curable resins include (meth) acrylate copolymers having an unsaturated bond in the ester side chain, as shown in the following general formula:

[Chemical 4] [Wherein R ¹ and R ² are each hydrogen or a methyl group,
Rf represents a fluoroalkyl group, and Rx represents a hydrocarbon group having an unsaturated bond. ]. The number average molecular weight of this (meth) acrylate copolymer is 50,000 to 5,000,000 (in terms of styrene)
Is preferred. Examples of the terminal group of the (meth) acrylate copolymer include hydrogen, an alkyl group (for example, a methyl group), an aryl group, and an arylalkyl group (for example, a benzyl group).

Examples of the Rx group include vinyl group, allyl group, acryl group, methacryl group and internal olefin. The Rf _{group, - (CH 2) a -} (CF 2) b -CF 3 [ wherein, a is 1 or 2, b is 2 to 6. ] Can be illustrated.

A third component may be copolymerized with this polymer in order to improve heat resistance. As such a third copolymerization component, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate
An acrylate etc. can be mentioned. Examples of the (meth) acrylate copolymer containing a fluorine atom include those represented by the formula:

[Chemical 5] [In the formula, Rf is fluoroalkyl, and R is alkyl. ] The compound shown by these is preferable.

Further, a polyurethane acrylate represented by the following general formula can be mentioned. This polymer can also contain fluorine atoms in order to obtain a suitable refractive index:

[Chemical 6] Alternatively,

[Chemical 7] [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ represent the same or different alkyl groups or fluoroalkyl groups. ]. Furthermore, (meth) acrylic compounds and fluorinated (meth) acrylic compounds can be mentioned. The molecular weight of the ultraviolet curable resin is usually 10 to 5,000,000. The amount of the ultraviolet curable resin is usually 50 to 99.99 parts by weight, preferably 90 to 99.9 parts by weight, based on 100 parts by weight of the resin composition.

The resin composition of the present invention may further contain a photopolymerization initiator. The photopolymerization initiator is preferably a compound that easily generates radicals upon irradiation with ultraviolet rays. Examples of the photopolymerization initiator are benzophenone, acetophenone, benzyl, benzoin, benzoin methyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, α, α′-azobisisobutyronitrile, benzoyl peroxide, 1-hydroxycyclohexyl phenyl ketone. , 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and the like. 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2
-Phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one are particularly preferred.
The amount of the photopolymerization initiator is usually 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin composition.

Since the resin composition is applied to the core glass uniformly and thinly, its viscosity is 100 to 10,000.
It is preferably cps. The resin composition may contain a reactive diluent in order to adjust the viscosity. An example of a reactive diluent is a (meth) acrylic compound. The (meth) acrylic compound, methyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) An acrylate etc. can be mentioned.

The reactive diluent may be a (meth) acrylic compound containing a fluorine atom for adjusting the refractive index. Such fluorinated (meth) acrylic compounds include trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and the formula:

[Chemical 8] [In the formula, R ¹ and R ² are hydrogen or a methyl group, x is 1 or 2, and y is an integer of 2 to 6. ]

[Chemical 9] [In the formula, R is H or CH ₃ , and n is 4 to 10. ]

[Chemical 10] [In the formula, R is H or CH ₃ , m is 1-2, and n is 4-1.
It is 0. ] The compound etc. which are shown by these can be mentioned. The amount of the reactive diluent is usually 89 parts by weight or less, preferably 20 to 89 parts by weight, based on 100 parts by weight of the resin composition.

The resin composition is applied onto a core made of quartz or optical glass by a method such as a die coating method or a spray coating method, and is irradiated with active light such as ultraviolet rays to be cured to form a clad material. By forming, the plastic clad optical fiber of the present invention can be manufactured.

The light irradiation amount is usually 10 to 5000 mJ.
/ Cm ² . The core diameter is usually 10-1000.
μm. The thickness of the clad is usually 1 to 100 μm.
m, preferably 5 to 50 μm

[0019]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples.

Examples 1 and 2 and Comparative Examples 1 and
2 Immediately after drawing the quartz glass rod to an outer diameter of 200 μm, a clad material having the composition shown in Table 1 is applied and UV-cured,
A plastic clad optical fiber having an outer diameter of 230 μm was obtained. Table 2 shows the pull-out strength at 25 ° C. between the connector fibers after attaching the crimp type connector to these plastic clad optical fibers.

[0021]

[Table 1]

[0022]

[Chemical 11]

[0023]

[Table 2]

[0024]

The plastic clad optical fiber according to the present invention has a large adhesive force between the core and the clad. Therefore, the risk of pulling out between the fiber connectors due to careless handling of the fibers after attaching the connectors is reduced as compared with the conventional one.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G02B 6/00 386 7036-2K

Claims (2)

[Claims] 1. A reactive compound having at least two silicon atoms bonded to at least two alkoxy groups and at least one functional group capable of forming a chemical bond with an ultraviolet curable resin in the same molecule. And a resin composition. 2. In an optical fiber having a silica or optical glass as a core and a plastic having a refractive index lower than that of the core as a clad, the clad material is a cured product of the resin composition according to claim 1. And plastic clad optical fiber.