JP4347233B2 - Optical fiber - Google Patents

Description

The present invention relates to an optical fiber element wires.

  When laying optical fiber cables, connection work is required for long-distance transmission and branching of transmission lines. In Japan, an optical fiber ribbon is generally used as an optical fiber cable. When different optical fiber cables are connected to each other, a connection operation of different optical fiber ribbons is performed.

  In the connection work of the optical fiber ribbon, after stripping the taped material and the wire coating material with the coating removal jig to expose the bare optical fiber, the bare optical fiber is removed to remove the remaining debris from the coating. After the surfaces of the optical fibers are cleaned and the end faces of the bare optical fibers are aligned by an optical fiber cutting jig, the bare optical fibers are fused and connected to each other by a fusion splicer, and the operation is completed. If the exposed bare optical fiber is damaged during this connection operation, the strength of the bare optical fiber is reduced.

  Therefore, conventionally, a tool for removing the coating and a method for removing the coating have been proposed in order to prevent a decrease in the strength of the bare optical fiber after the removal of the coating (see, for example, Patent Document 1 and Patent Document 2). .

However, in these methods, even if an appropriate tool or method is used, in the process of removing the coating of the optical fiber and cleaning the exposed surface of the bare optical fiber when connecting the optical fiber cable, In some cases, the strength of the bare fiber was reduced.
JP-A-5-181021 JP-A-6-186434

The present invention has been made in view of the above circumstances, and an object thereof is to provide a suppressing optical fiber element wires the decrease in strength at the time of connection work.

The present invention is an optical fiber strand in which a primary coating layer and a secondary coating layer made of an ultraviolet curable resin are provided on the outer periphery of an optical fiber bare wire, and the ultraviolet curable resin forming the primary coating layer includes: tetraethoxysilane 0.1 parts by mass or more, 3.0 parts by unrealized or less and, diethylamine 0.001 parts by mass or more, to provide 0.2 parts by mass or less including the optical fiber.

According to the optical fiber of the present invention, it is possible to prevent the strength of the bare optical fiber from being lowered in the process of removing the coating layer of the optical fiber and cleaning the exposed surface of the bare optical fiber. Can do. In addition, an optical fiber strand that has been manufactured for a long time has a smaller decrease in strength of the bare optical fiber in the operation of removing the coating layer than an optical fiber strand immediately after manufacture. Further, if an amine-based substance is added to the ultraviolet curable resin forming the primary coating layer, the silane coupling agent reacts with the quartz glass forming the optical fiber bare wire in the bare optical fiber after the coating layer is removed. Time can be shortened.
In this way, by removing the coating layer of the optical fiber strand and reducing the decrease in the strength of the exposed bare optical fiber, the workability at the time of connecting the optical fiber strand is improved, and the optical fiber strand is reused. It is possible to realize prevention of cutout due to an increase in connection work, reduction in risk of breakage of the connection portion, and the like.

  Hereinafter, an optical fiber strand embodying the present invention, and an optical fiber ribbon and an optical fiber cable using the same will be described in detail.

FIG. 1 is a schematic sectional view showing an embodiment of the optical fiber of the present invention.
The optical fiber 20 of this embodiment includes an optical fiber bare wire 10 composed of a core and a clad mainly composed of quartz glass, and a primary coating layer 11 and a secondary layer sequentially provided on the outer periphery of the optical fiber bare wire 10. The coating layer 12 is schematically configured.

  Examples of the material forming the primary coating layer 11 and the secondary coating layer 12 include ultraviolet curable resins such as urethane acrylate, epoxy acrylate, and butadiene acrylate.

  The ultraviolet curable resin forming the primary coating layer 11 contains 0.1 to 3.0 parts by mass of a low molecular weight silane coupling agent that is not incorporated into the skeleton of the ultraviolet curable resin. Preferably contains 0.1 parts by mass or more and 2.0 parts by mass or less of a low molecular weight silane coupling agent, and more preferably contains 0.25 parts by mass or more and 1.5 parts by mass or less.

  If the low molecular weight silane coupling agent contained in the ultraviolet curable resin forming the primary coating layer 11 is 0.1 parts by mass or more and 3.0 parts by mass or less, the primary coating layer 11 and the secondary coating layer 12 (hereinafter, These may be collectively referred to as a “coating layer”), and in the process of cleaning the exposed surface of the bare optical fiber 10, it is possible to prevent the strength of the bare optical fiber 10 from being lowered. it can. In addition, the optical fiber 20 that has been manufactured for a long time has a smaller decrease in the strength of the bare optical fiber 10 in the operation of removing the coating layer than the optical fiber 20 that has just been manufactured.

  Furthermore, the molecular weight of the low molecular weight silane coupling agent contained in the ultraviolet curable resin forming the primary coating layer 11 is preferably 100 or more and 600 or less, and more preferably 100 or more and 500 or less.

  If the molecular weight of the low molecular weight silane coupling agent contained in the ultraviolet curable resin forming the primary coating layer 11 is within the above range, in the process of cleaning the exposed surface of the bare optical fiber 10, the bare optical fiber 10 It can prevent that the intensity | strength of this falls. In addition, the optical fiber 20 that has been manufactured for a long time has a smaller decrease in the strength of the bare optical fiber 10 in the operation of removing the coating layer than the optical fiber 20 that has just been manufactured.

  Although it does not specifically limit as a low molecular weight silane coupling agent contained in the ultraviolet curable resin which forms such a primary coating layer 11, For example, diethoxydimethylsilane, dimethoxydimethylmethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenyl Silane, n-dodecyltriethoxysilane, ethyltriethoxysilane, n-hexyltrimethoxysilane, methyltriethoxysilane, n-octadecyltriethoxysilane, octadecyltrimethoxysilane, n-octyltriethoxysilane, phenyltriethoxysilane, Examples include phenyltrimethoxysilane, trimethoxymethylsilane, and trimethoxy-n-propylsilane.

  Further, the ultraviolet curable tree constituting the primary coating layer 11 preferably contains 0.001 part by mass or more of an amine substance, and practically 0.01 parts by mass or more and 0.2 parts by mass or less of an amine substance. More preferably.

  If the amine-based material contained in the ultraviolet curable resin forming the primary coating layer 11 is 0.001 part by mass or more, the silane coupling agent and the optical fiber bare wire in the bare optical fiber 10 after the coating layer is removed The time for reaction with the quartz glass forming 10 (bonding with the silane coupling agent and quartz glass) can be shortened. Specifically, after removing the coating, the time required to reduce the decrease in the strength of the bare optical fiber 10 that was 3 months or more when the amine-based material is not included is included in the amine-based material. Can be shortened to about one week.

An example of the amine material is diethylamine .

The optical fiber 20 of this embodiment can prevent the strength of the bare optical fiber 10 from being lowered in the process of removing the coating layer and cleaning the exposed surface of the bare optical fiber 10. In addition, the reaction between the silane coupling agent and the quartz glass forming the bare optical fiber proceeds with the passage of time after the coating layer is removed, and the decrease in strength of the bare optical fiber 10 is reduced. Further, if an amine-based substance is added to the ultraviolet curable resin forming the primary coating layer 11, the silane coupling agent and the quartz glass forming the optical fiber bare wire 10 in the bare optical fiber 10 after removing the coating layer The reaction time can be shortened.
Thus, by removing the coating layer of the optical fiber strand 20 and reducing the decrease in strength of the bare optical fiber 10 exposed, the workability at the time of connecting the optical fiber strand 20 is improved. It is possible to prevent the lack of scale due to the increase in the reconnection work of the wire 20 and to reduce the risk of breakage of the connection portion.

In addition, a colored layer may be provided on the outer periphery of the optical fiber 20 to form a dyed wire.
Such a dyed wire can prevent the strength of the bare optical fiber from being lowered when the optical fiber 20 constituting the same is connected to another optical fiber.

Alternatively, a plurality of optical fiber strands 20 may be arranged in a line at an equal pitch, and these may be covered with a covering material in a lump to form a tape-shaped optical fiber ribbon.
Such an optical fiber ribbon can prevent the strength of the bare optical fiber from being lowered when the optical fiber 20 constituting the optical fiber tape is connected to another optical fiber.

Furthermore, the outer periphery of the optical fiber 20 may be surrounded by a buffer material such as jelly and yarn, and the optical fiber 20 may be collectively covered with a coating layer together with the buffer material to form an optical fiber cable.
Such an optical fiber cable can prevent the strength of the bare optical fiber from being lowered when the optical fiber 20 constituting the optical fiber cable is connected to another optical fiber.

Next, a method for manufacturing the optical fiber 20 of this embodiment will be described.
In the method of manufacturing the optical fiber strand 20 of this embodiment, first, an optical fiber preform mainly composed of quartz glass is attached in a spinning furnace so as to be movable in the axial direction, and then argon (Ar), helium In an inert gas atmosphere such as (He), the lower end portion is heated to about 2000 ° C. at a high temperature, melt-spun, and the bare optical fiber 10 is obtained.

  Subsequently, the bare optical fiber 10 is sent into the cooling cylinder, or the bare optical fiber 10 is rapidly cooled to a temperature suitable for forming the primary coating layer 11 in the next step by natural cooling.

  Subsequently, the cooled bare optical fiber 10 is coated with an ultraviolet curable resin so as to cover the outer periphery thereof in the first coating layer coating apparatus for forming the primary coating layer. The primary coating layer 11 is formed by being cured by light such as ultraviolet rays emitted from a crosslinking lamp formed of a UV lamp or the like provided in the first crosslinking cylinder.

  Furthermore, in the second coating layer coating apparatus for forming the secondary coating layer, an ultraviolet curable resin is applied so as to cover the outer periphery of the primary coating layer 11, and then this ultraviolet curable resin is applied to the second cross-linking cylinder. The secondary coating layer 12 is formed by being cured by light such as ultraviolet rays irradiated from a bridge lamp composed of a provided UV lamp or the like, and the optical fiber 20 is formed.

  Further, the direction of the optical fiber 20 is changed in another direction by a turn pulley, and is wound around a winding drum through a take-up machine and a dancer roll.

  Hereinafter, the present invention will be described more specifically with experimental examples, but the present invention is not limited to the following experimental examples.

(Experimental example 1)
Primary coating with different addition amount of low molecular weight silane coupling agent by changing the addition amount of low molecular weight silane coupling agent to UV curable resin for forming primary coating layer of optical fiber Eight types of optical fiber strands with layers were fabricated.
Tetraethoxysilane having a molecular weight of 208 was used as the low molecular weight silane coupling agent.
For these optical fiber strands, the coating layer was removed with a hot jacket stripper, and then the surface of the bare optical fiber was wiped with a Kim wipe soaked in ethanol. The strength characteristics of the wire were evaluated.
The strength of the bare optical fiber after removing the coating layer was measured by measuring the two-point bending strength of the bare optical fiber. The test speed in this two-point bending strength measurement was 100 μm / s. The strength was measured one week and three months after the production of the optical fiber.
The results are shown in Table 1.

  From the results in Table 1, the strength of the bare optical fiber after the coating layer is removed is low after one week from manufacture. However, after 3 months from manufacture, the coating layer of the optical fiber having a primary coating layer to which a low molecular weight silane coupling agent is added in an amount of 0.1 parts by mass or more and 3.0 parts by mass or less is removed and exposed. It was confirmed that the strength of the bare optical fiber increased. In addition, it was confirmed that when the addition amount of the low molecular weight silane coupling agent is 0.1 parts by mass or more and 3.0 parts by mass or less, the decrease in strength becomes smaller as the addition amount increases.

(Experimental example 2)
A primary in which low molecular weight silane coupling agents having different molecular weights are added according to a predetermined production method by changing the molecular weight of the low molecular weight silane coupling agent with respect to the ultraviolet curable resin for forming the primary coating layer of the optical fiber. Six types of optical fiber strands with coating layers were made.
The addition amount of the low molecular weight silane coupling agent was 0.5 parts by mass.
For these optical fiber strands, the coating layer was removed with a hot jacket stripper, and then the surface of the bare optical fiber was wiped with a Kim wipe soaked in ethanol. The strength characteristics of the wire were evaluated.
The strength of the bare optical fiber after removing the coating layer was measured by measuring the two-point bending strength of the bare optical fiber. The test speed in this two-point bending strength measurement was 100 μm / s. The strength was measured 3 months after the production of the optical fiber.
The results are shown in Table 2.

  From the results of Table 2, if the molecular weight of the low molecular weight silane coupling agent is 100 or more and 600 or less, the strength of the bare optical fiber exposed by removing the coating layer of the optical fiber after 3 months from the production Was confirmed to be high.

(Experimental example 3)
By changing the addition amount of the low molecular weight silane coupling agent and the addition amount of the amine-based material to the ultraviolet curable resin for forming the primary coating layer of the optical fiber strand, the low molecular weight silane cup is changed by a predetermined production method. Seven types of optical fiber wires having primary coating layers with different amounts of ring agent and amine were added.
Tetraethoxysilane having a molecular weight of 208 was used as the low molecular weight silane coupling agent.
As an amine-based material, for these optical fiber strands using diethylamine, after removing the coating layer with a hot jacket stripper, and wiping the surface of the bare optical fiber with a Kimwipe dipped in ethanol as a sample, The strength characteristics of the bare optical fiber after removing the coating layer were evaluated.
The strength of the bare optical fiber after removing the coating layer was measured by measuring the two-point bending strength of the bare optical fiber. The test speed in this two-point bending strength measurement was 100 μm / s. The strength was measured one week after the production of the optical fiber.
The results are shown in Table 3.

  From the results of Table 3, if the added amount of the amine-based material is 0.001 part by mass or more, the strength of the bare optical fiber exposed by removing the coating layer of the optical fiber one week after production is reduced. Was confirmed to be small. Further, if the addition amount of the amine-based substance is 0.01 parts by mass or more, even if the addition amount of the low molecular weight silane coupling agent is less than 0.1 parts by mass, the optical fiber element after one week from the production is obtained. It was confirmed that the strength of the bare optical fiber exposed by removing the coating layer of the wire was high.

  The optical fiber of the present invention, and the optical fiber ribbon and the optical fiber cable using the optical fiber are used for information communication, and can be applied to all kinds of optical fibers such as a single mode fiber and a dispersion shifted fiber. Moreover, the optical fiber strand of this invention, the optical fiber colored core wire using this, and an optical fiber tape core wire are applicable also as an optical component.

It is a schematic sectional drawing which shows one Embodiment of the optical fiber strand of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Bare optical fiber, 11 ... Primary coating layer, 12 ... Secondary coating layer, 20 ... Optical fiber strand.

Claims (1)

An optical fiber in which a primary coating layer and a secondary coating layer made of an ultraviolet curable resin are provided on the outer periphery of a bare optical fiber,
The ultraviolet curable resin forming the primary coating layer, tetraethoxysilane 0.1 parts by mass or more, 3.0 parts by unrealized or less and, diethylamine 0.001 parts by mass or more, containing 0.2 parts by mass or less optical fiber, characterized in Mukoto.

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