JPH0481704A - Novel plastic clad optical fiber - Google Patents

Abstract

PURPOSE:To prevent the holding power between an optical fiber and a connector from degrading and a core from projecting at high temps. by using the cured matter of a photosetting resin compsn. consisting of respectively specific ratios of ladder type silicone, (meth)acrylate and photopolymn. initiator as a clad material. CONSTITUTION:The cured matter of the photosetting resin compsn. consisting of 9.99 to 95wt.% ladder type silicone expressed by formula I, 4.99 to 90wt.% (meth)acrylate and 0.01 to 10wt.% photopolymn. initiator is used as the clad material. In the formula I, R<1> and R<2> are an alkyl group or aryl group which may contain a fluorine atom; X<1> to X<4> are hydrogen atoms, alkyl groups or polyorganosiloxane groups; (n) is an integer >=2. The degradation in the mechanical characteristics at a high temp. is lessened in this way and the degradation in the holding power between a pressure contact type connector and the optical fiber is lessened even in a high temp. and the extent of the projection of the core from the front end of the connector after resting at a high temp. is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to plastic-clad optical fibers.

[Prior Art] Conventionally, cladding materials for plastic clad optical fibers include Noricone resin (Japanese Unexamined Patent Publication No. 5830703), polyfluoroalkyl methacrylate copolymer (
JP-A No. 66706), vinylidene fluoride/tetrafluoroethylene copolymer (JP-A No. 56-4196)
6) is known. Also, JP-A-62-250
As disclosed in Japanese Patent No. 047 and US Pat. No. 4,707,076, cladding materials using ultraviolet curable resin compositions have been proposed. Since these resin compositions have a crosslinked structure through ultraviolet curing, they have advantages not found in conventional compositions, such as excellent mechanical strength and improved production speed of optical fibers.

However, these cladding materials are no longer able to meet the advanced demands of recent years, such as simplification of connector attachment using a caulking method and maintenance of mechanical strength at high temperatures. For example, with Noricone resin, it is not possible to process the terminals by attaching a caulking type connector due to insufficient mechanical strength. Although polyfluoroalkyl methacrylate copolymer has excellent transparency, it has poor adhesion to the core glass, and it can be pulled out with weak force at the caulked end. Furthermore, since the copolymer of hynylidene fluoride/tetrafluoroethylene has a large loss due to absorption and scattering, it is impossible to reduce the loss of an optical fiber. On the other hand, UV-curable fluorinated acrylate has a fast curing speed and good processability, and the resin itself has excellent mechanical strength and low optical transmission loss, making it suitable as a cladding material. It is often used in However, the mechanical strength decreases significantly at temperatures above 80°C, and the mechanical strength at high temperatures is insufficient.
There was a problem that the holding force between the optical fiber and the connector was reduced. Furthermore, there were other problems such as the protrusion of the core at high temperatures.

``Problems to be Solved by the Invention'' Two objects of the present invention are to provide a plastic clad optical fiber that solves the above-mentioned problems.

[Means for Solving the Problems 2] The gist of the present invention is as follows: (A) General formula [In the formula, R1-R2 are an alkyl group or an aryl group which may contain a fluorine atom, and X1 to X' are a hydrogen atom, an alkyl group or a polyorganonoloxane group,
n is a number of 2 or more. From 9.99 to 95% by weight of ladder type silicone represented by Otsu, (B) 4.99 to 90% by weight of (meth)acrylic acid ester, and (C) 0.01 to 10% by weight of photopolymerization initiator. The present invention relates to a plastic clad optical fiber whose cladding material is a cured product of a photocurable resin composition.

In order for the cured product of the resin composition to function as a cladding material, the refractive index must be lower than that of the core material. As a means for this purpose, the ladder type silicone (A) can contain a substituent having a fluorine atom such as a fluorinated alkyl group.

Specific examples of ladder-type silicone (A) include:
It is as follows.

CH.

CH3 [n is 2 or more. ] [Q is 2 or more, m is 1 or more, and n is 1 or more. The amount of colladder type noricorn (A) is 999 to 95% of the resin composition.
Weight%.

As the (meth)acrylic acid ester (B), methyl (meth)acrylate, noclohexynol (meth)acrylate, isobonyl (meth)acrylate, ethylene glycol (meth)acrylate, neopentyl glycol (meth)acrylate, trimethylolpropanetri (Meth)acrylate etc. can be mentioned.

Furthermore, this (meth)acrylic ester may contain a fluorine atom in order to adjust the refractive index. It is preferable that at least one of the (meth)acrylic esters (B) is a fluorinated (meth)acrylic ester. Such fluorinated (meth)acrylic acid esters include trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, heptadecafluorodene (
meth)acrylate and formula: R' R.

(:H,=CC00(CHI)X(CF2)y(CI
7)XOCOC=CI.

[In the formula, R1 and R2 are hydrogen or a methyl group, X is 1 or 2, and y is an integer from 2 to 6.

Examples include compounds represented by:

In addition, in order to improve the compatibility between the ladder-type noricorn and the above (meth)acrylic ester, and to chemically bond the (meth)acrylic ester and the ladder-type noricorn after curing, it is necessary to chemically bond the (meth)acrylic ester and the ladder-type noricorn to each other by containing a silicon atom (meth). Acrylic esters can be added. It is preferable that at least one of the (meth)acrylic esters contains a silicon atom.

Examples of (meth)acrylic esters containing silicon atoms include 3-methacryloquinoprobyltrimethoquinonolane,
]-(]3-methacryloquinobrovir 1.1.3.3.
3-bentylinoneloxane, 3-methacryloquinepropyltris(trimethylchloroquine)ran.

The amount of (meth)acrylic acid ester is 49% of the resin composition.
The content is preferably 9 to 90% by weight.

The photopolymerization initiator (C) is preferably a compound that easily generates radicals upon irradiation with ultraviolet rays, and examples thereof include the following compounds. Hensiphenone, acetophenone,
Hensil, hengeine, hengeine methyl ether, hengeine isobutyl ether, hennolz methyl ketal, α,α゛-azohisisobutyronitrile, henzyl peroxide, l-hydroquinone chloroquinorphenyl ketone, 22-dimethoxy-2- Phenylacetophenone, 2-hydroquine-2-methyl-1-phenylpropan-1-one. In particular, when used as a clad material for ultraviolet light guiding fibers, l-hydroquinone chlorohequinyl phenyl ketone and 2-hydroquino-2-methyl-
-Phenylpropane-1-ono is preferred.

The amount of photopolymerization initiator (C) is 001-10 of the resin composition.
Preferably, it is % by weight.

A resin composition is applied onto a core made of quartz or optical glass using a method such as a die coating method or a spray coating method, and is cured by irradiation with active light such as ultraviolet rays to form a crat material. , the plastic-clad optical fiber of the present invention can be manufactured. The amount of light irradiation can be determined as appropriate depending on the type and amount of the compound contained in the composition. The irradiation dose is usually lO~
Calculate at 5000 mJ/cm'.

Since the ladder-type nori cone has excellent heat resistance, the plastic-clad optical fiber of the present invention exhibits excellent mechanical properties even at high temperatures, and the retention strength between the optical core and the connector does not decrease significantly (and the core does not protrude). In addition, ladder-type silicone has excellent adhesion to glass, and therefore the plastic clad optical fiber of the present invention also has excellent adhesion between the core and clad.

Further, since the resin composition used for the clad material is photocured, the plastic clad optical fiber of the present invention is characterized by excellent productivity.

Furthermore, this resin composition has sufficient mechanical strength after curing, and the plastic-clad optical fiber of the present invention can be terminal-treated by attaching a crimp-type connector.

[One Preferred Embodiment of the Invention] The present invention will be specifically described below with reference to Examples and Comparative Examples. In Examples and Comparative Examples, parts represent parts by weight unless otherwise specified.

Examples 1 to 2 and Comparative Examples 1 to 5 Immediately after drawing a glass rod to an outer diameter of 200 μm, a resin composition having the composition shown in Table 1 was applied and UV-cured to form a cladding material. A 230 μm polymer clad optical fiber was obtained.

Table 2 shows the physical properties when crimp type optical connectors are attached to these optical fibers.

Ladder type silicone: CH3 acrylic copolymer m: x:y:z=I:8・I [Effects of the invention] The plastic clad optical fiber of the present invention has little deterioration in mechanical properties at high temperatures of 85°C or higher. Even under high temperatures, the retention force between the crimp type connector and the optical fiber does not decrease much, and the amount of core protrusion from the connector tip after being left under high temperatures is also small. Therefore, for example, crimp-type connector attachment is useful as an optical fiber for short-distance optical communication systems while being used under high temperatures.

Patent applicant Sumitomo Electric Industries, Ltd.

Claims (1)

[Claims] 1. (A) General formula: ▲ Numerical formula, chemical formula, table, etc. ▼ [I] [In the formula, R^1 to R^2 are an alkyl group that may contain a fluorine atom or It is an aryl group, X^1 to X^4 are hydrogen atoms, alkyl groups, or polyorganosiloxane groups, and n is a number of 2 or more. ] 9.99 to 95% by weight of ladder-type silicone represented by (B) 4.99 to 90% by weight of (meth)acrylic acid ester, and (C) 0.01 to 10% by weight of photopolymerization initiator. A plastic clad optical fiber whose cladding material is a cured product of a photocurable resin composition.