JPH05107432A - Single core separation type optic fiber unit - Google Patents

Abstract

PURPOSE:To provide a single core separation type optic fiber unit which is excellent in the connection work, the temperature characteristic and the coloring characteristic and which is cheap. CONSTITUTION:A first layer 6 composed of two covering layers for assembling a plurality of optic fibers coated with ultraviolet radiation curable resin and covering the same in one bundle, is made of ultraviolet radiation hardenable resin containing therein 1wt.% of white ink and having a Young's modulus of less than 0.3 kg/mm<2> and a second layer is made of ultraviolet radiation hardenable resin having a Young's modules of less than 720kg/mm<2>. The optic fibers 1 are assembled in a circular cross-sectional shape and are covered in one bundle by means of two ultraviolet hardenable resin layers 6, 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-core separation type optical fiber in which a plurality of UV-curable resin-coated optical fibers (hereinafter referred to as UV-coated optical fibers) are assembled and collectively coated with two layers of UV-curable resin. It relates to a fiber unit.

[0002]

2. Description of the Related Art Conventionally, a single-fiber separation type optical fiber unit as shown in FIG. 2 is well known. This is one in which optical fiber core wires 3 each having a buffer layer 2 of silicone provided on the outer periphery of an optical fiber 1 are gathered, and a protective layer 4 is integrally covered again with silicone.

However, the above-mentioned materials have a problem that the curing rate of silicone at the time of production is slow, the production linear velocity does not increase, and the cost is high. For such problems, various materials have been studied, and as a result, it has been proposed to apply an ultraviolet curable resin to the buffer layer 2 and the protective layer 3. By using the ultraviolet curable resin having a high curing speed in this way, productivity can be improved and cost can be reduced.

[0004]

However, since the optical fiber unit made of the above-mentioned material has a structure in which a circular cross section is collectively coated, it has a high Young's modulus, for example, 20 kg in order to have lateral pressure resistance. / Mm ² or more of UV curable resin is applied, and at least 2 cores or more of multi-core UV optical fibers are collectively covered, so it is difficult to separate each core when performing terminal treatment. Is complicated and the workability is poor. Further, the shrinkage of the ultraviolet curable resin at a low temperature was large, and the increase of light loss was likely to occur. Further, although color ink is mixed in the protective layer 4 for each color of the optical fiber unit itself, there is a problem that white and gray cannot be distinguished because the coating thickness of the protective layer 4 is thin. Therefore, it has been difficult to put the single-fiber optical fiber unit made of the ultraviolet curable resin into practical use in terms of connection workability, temperature characteristics, and color characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a low cost single-fiber optical fiber unit which is excellent in connection workability, temperature characteristics and color characteristics.

[0006]

In order to achieve the above object, the present invention provides a single-core separated type optical fiber in which a plurality of optical fibers coated with a UV-curable resin are assembled and are collectively coated with two layers of the UV-curable resin. In the fiber unit, the first layer of the coating layer has a Young's modulus of 0.3 kg / mm ² or less in which 1% or less of the weight of the first layer is mixed, and the second layer is 20 kg. The optical fiber has a Young's modulus of not more than 1 mm ² / mm ² , and is provided with a structure in which the two layers of the ultraviolet curable resin are used to collect the optical fibers in a circular cross-section or in a tape shape and collectively coat them.

[0007]

[Function] Since the inner coating layer of the first layer has a low Young's modulus of 0.3 kg / mm ² or less, when the UV coated optical fiber is branched when the cable is laid, the UV coating resin for collective coating is removed and Easy to separate. When the Young's modulus of the inner coating layer is 0.3 kg / mm ² or less, the optical loss does not increase even if the temperature is cooled to -70 ° C. Furthermore, by adding 1% of white ink to the inner coating layer in a weight ratio of the first layer,
The base becomes white, and each optical fiber unit can be color-coded.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing an embodiment of the present single-core separated optical fiber unit, in which six optical fiber core wires 3 each having a buffer layer 5 made of an ultraviolet curable resin around the optical fiber 1 are provided. And a two-layer coating layer made of an ultraviolet curable resin, that is, an inner coating layer 6 and an outer coating layer 7 are integrally coated on the above. In this optical fiber unit, the inner coating layer 6 of the first layer is mixed with white ink in an amount of 1% or less of the weight of the first layer 0.3 kg / mm ²
The ultraviolet curable resin having the following Young's modulus is
An ultraviolet curable resin having a Young's modulus of 20 kg / mm ² or less is used for the outer coating layer 7 of the second layer, and the six optical fiber core wires 3 have a circular cross section by the two coating layers 6 and 7. It is covered in a batch.

The first inner coating layer 6 is 0.3 kg / mm ²
Because of the following low Young's modulus, U when cable is laid
At the time of branching the V-coated optical fibers, it is possible to easily and stably and surely remove and separate the UV-curable resin collectively coated, for example, separate the UV-coated optical fibers having a diameter of 0.4 mm.

The optical fiber unit has a temperature of -7.
Even if the temperature is lowered to 0 ° C, the optical loss does not increase. The reason is that the Young's modulus of the inner coating layer 6 is specified to be 0.3 kg / mm ² or less. Reason why the Young's modulus and 0.3 kg / mm ² or less, a Young's modulus ^{0.1kg / mm 2, 0.3kg / mm} 2,
^{5kg / mm 2, 23kg / mm} 2, was subjected to cold test using a material ^{44kg / mm 2, 5kg / mm} 2 or more of the single-mode light by -40 ℃ from -30 ° C. greater shrinkage of the resin is The optical loss of the fiber at 1.55 μm wavelength was about 0.10 dB / Km, which was clearly increased, whereas the resin of 0.3 kg / mm ² or less showed the minimum cooling temperature of the thermostatic chamber − This is because no increase in light loss was observed up to 70 ° C.

Further, by adding 1% (the weight ratio of the inner coating layer) of the maximum amount of white ink which can be cured by ultraviolet rays to the inner coating layer 6, the base becomes white, and each optical fiber unit is color-coded. The color of each ink mixed in the outer side 7 of the coating layer emerged, and gray and white could be more clearly distinguished, which was highly reliable.

The optical fiber unit is not limited to have a circular cross section, but a plurality of optical fiber core wires 3 may be arranged in parallel, and two layers of collective coating may be applied thereon.

[0014]

As described above, the single-fiber-separated optical fiber unit of the present invention is capable of easily separating the optical fibers into single-core fibers during connection work, and is also excellent in low-temperature characteristics and color-coding characteristics. Furthermore, the curing speed of the ultraviolet curable resin is higher than that of the conventional silicone resin, and the production linear speed is increased, and the cost is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a single-fiber separation optical fiber unit of the present invention.

FIG. 2 is a sectional view of a conventional single-fiber separation optical fiber unit.

[Explanation of symbols]

 1 Optical fiber 2 Buffer layer (3 Optical fiber core wire 4 Protective layer 5 Buffer layer 6 Inner coating layer (first layer) 7 Outer coating layer (second layer)

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[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-core separation type optical fiber in which a plurality of UV-curable resin-coated optical fibers (hereinafter referred to as UV-coated optical fibers) are assembled and collectively coated with two layers of UV-curable resin. It relates to a fiber unit.

[0002]

2. Description of the Related Art Conventionally, a single-fiber separation type optical fiber unit as shown in FIG. 2 is well known. This is one in which optical fiber core wires 3 each having a buffer layer 2 of silicone provided on the outer periphery of an optical fiber 1 are gathered, and a protective layer 4 is integrally covered again with silicone.

However, the above-mentioned materials have a problem that the curing rate of silicone at the time of production is slow, the production linear velocity does not increase, and the cost is high. For such problems, various materials have been studied, and as a result, it has been proposed to apply an ultraviolet curable resin to the buffer layer 2 and the protective layer 3. By using the ultraviolet curable resin having a high curing speed in this way, productivity can be improved and cost can be reduced.

[0004]

However, since the optical fiber unit made of the above-mentioned material has a structure in which a circular cross section is collectively coated, it has a high Young's modulus, for example, 20 kg in order to have lateral pressure resistance. / Mm ² or more of UV curable resin is applied, and at least 2 cores or more of multi-core UV optical fibers are collectively covered, so it is difficult to separate each core when performing terminal treatment. Is complicated and the workability is poor. Further, the shrinkage of the ultraviolet curable resin at a low temperature was large, and the increase of light loss was likely to occur. Further, although color ink is mixed in the protective layer 4 for each color of the optical fiber unit itself, there is a problem that white and gray cannot be distinguished because the coating thickness of the protective layer 4 is thin. Therefore, it has been difficult to put the single-fiber optical fiber unit made of the ultraviolet curable resin into practical use in terms of connection workability, temperature characteristics, and color characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a low cost single-fiber optical fiber unit which is excellent in connection workability, temperature characteristics and color characteristics.

[0006]

In order to achieve the above object, the present invention provides a single-core separated type optical fiber in which a plurality of optical fibers coated with a UV-curable resin are assembled and are collectively coated with two layers of the UV-curable resin. In the fiber unit, the first layer of the coating layer has a Young's modulus of 0.3 kg / mm ² or less in which 1% or less of the weight of the first layer is mixed, and the second layer is 20 kg. The optical fiber has a Young's modulus of not more than 1 mm ² / mm ² , and is provided with a structure in which the two layers of the ultraviolet curable resin are used to collect the optical fibers in a circular cross-section or in a tape shape and collectively coat them.

[0007]

[Function] Since the inner coating layer of the first layer has a low Young's modulus of 0.3 kg / mm ² or less, when the UV coated optical fiber is branched when the cable is laid, the UV coating resin for collective coating is removed and Easy to separate. When the Young's modulus of the inner coating layer is 0.3 kg / mm ² or less, the optical loss does not increase even if the temperature is cooled to -70 ° C. Furthermore, by adding 1% of white ink to the inner coating layer in a weight ratio of the first layer,
The base becomes white, and each optical fiber unit can be color-coded.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing an embodiment of the present single-core separated optical fiber unit, in which six optical fiber core wires 3 each having a buffer layer 5 made of an ultraviolet curable resin around the optical fiber 1 are provided. And a two-layer coating layer made of an ultraviolet curable resin, that is, an inner coating layer 6 and an outer coating layer 7 are integrally coated on the above. In this optical fiber unit, the inner coating layer 6 of the first layer is mixed with white ink in an amount of 1% or less of the weight of the first layer 0.3 kg / mm ²
The ultraviolet curable resin having the following Young's modulus is
An ultraviolet curable resin having a Young's modulus of 20 kg / mm ² or less is used for the outer coating layer 7 of the second layer, and the six optical fiber core wires 3 have a circular cross section by the two coating layers 6 and 7. It is covered in a batch.

The inner coating layer 6 of the first layer is 0.3 kg / mm ²
Because of the following low Young's modulus, U when cable is laid
At the time of branching the V-coated optical fibers, it is possible to easily and stably and surely remove and separate the UV-curable resin collectively coated, for example, separate the UV-coated optical fibers having a diameter of 0.4 mm.

The optical fiber unit has a temperature of -7.
Even if the temperature is lowered to 0 ° C, the optical loss does not increase. The reason is that the Young's modulus of the inner coating layer 6 is specified to be 0.3 kg / mm ² or less. Reason why the Young's modulus and 0.3 kg / mm ² or less, a Young's modulus ^{0.1kg / mm 2, 0.3kg / mm} 2,
^{5kg / mm 2, 23kg / mm} 2, was subjected to cold test using a material ^{44kg / mm 2, 5kg / mm} 2 or more of the single-mode light by -40 ℃ from -30 ° C. greater shrinkage of the resin is The optical loss of the fiber at 1.55 μm wavelength was about 0.10 dB / Km, which was clearly increased, whereas the resin of 0.3 kg / mm ² or less showed the minimum cooling temperature of the thermostatic chamber − This is because no increase in light loss was observed up to 70 ° C.

Further, by adding 1% (the weight ratio of the inner coating layer) of the maximum amount of white ink which can be cured by ultraviolet rays to the inner coating layer 6, the base becomes white, and each optical fiber unit is color-coded. The color of each ink mixed in the outer side 7 of the coating layer emerged, and gray and white could be more clearly distinguished, which was highly reliable.

The optical fiber unit is not limited to have a circular cross section, but a plurality of optical fiber core wires 3 may be arranged in parallel, and two layers of collective coating may be applied thereon.

[0014]

As described above, the single-fiber-separated optical fiber unit of the present invention is capable of easily separating the optical fibers into single-core fibers during connection work, and is also excellent in low-temperature characteristics and color-coding characteristics. Furthermore, the curing speed of the ultraviolet curable resin is higher than that of the conventional silicone resin, and the production linear speed is increased, and the cost is reduced.

Claims (1)

[Claims] 1. A single-core separation type optical fiber unit in which a plurality of optical fibers coated with a UV-curable resin are assembled and coated with two layers of a UV-curable resin at once, wherein the first layer of the coating layer is the first layer. It has a Young's modulus of 0.3 kg / mm ² or less mixed with 1% or less of the layer weight of white ink.
The single-fiber-separated optical fiber unit having a Young's modulus of 20 kg / mm ² or less.