JPH1062662A - Optical coated fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the leading of an optical coated fiber and utilize an existing batch fusing machine by forming an intermediate layer formed of a resin having releasing property on the optical coated fiber, and providing a coating layer having a specified Young's modulus. SOLUTION: A primary coating layer 2 and a secondary coating layer 3 formed of an ultraviolet ray hardening resin are successively provided on the circumference of an optical crude fiber 1, whereby an optical coated fiber 4 is formed. An intermediate layer 5 formed of a resin having releasing property is provided on the circumference of the optical coated fiber 4, and a coating layer 6 having a Young's modulus of 50-150kgf/mm<2> is provided thereon, whereby an optical fiber 7 is formed. The optical fiber 7 is thus low tough with a small elongation of the coating layer 5, and can be easily notched by a tool such as mechanical stripper. The outer diameter C of the optical fiber 7 is set to 450-550μm, so that a batch fusion can be performed by use of an existing multifiber fusing machine as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber core, and more particularly to an optical fiber core which has good handleability, can be connected collectively, and can easily lead out an optical fiber.

[0002]

2. Description of the Related Art Conventionally, an optical fiber having an outer diameter of 250 μm, in which a bare optical fiber is coated with a UV curable resin or the like, has been widely used. Since the optical fiber is thin and lacks rigidity, it is difficult to handle it during connection work and the like, and loss (handling loss) due to lateral pressure or the like is likely to occur during handling. Therefore, a coating layer made of nylon is provided on this optical fiber and its outer diameter is set to 600 to 90.
An optical fiber core having a diameter of 0 μm has been proposed. The nylon forming this coating layer generally has a Young's modulus (A
(According to STM D638) 90 to 150 kg / mm ² is used.

[0003]

By the way, in the case of connecting the optical fiber, the covering layer is peeled off, and the optical fiber is drawn out and then connected. This mouth is
For example, a small notch or notch (notch) is formed in the coating layer with a tool such as a mechanical stripper, and the coating layer is peeled from the notch. However, in the conventional optical fiber core, it is difficult to form a notch with a tool such as a mechanical stripper because the nylon forming the coating layer has high toughness. In addition, due to the nature of nylon, the coating layer and the optical fiber are adhered to each other, and the coating layer is difficult to be peeled off. .

[0004] A batch fusion splicer is used to simultaneously connect a plurality of optical fiber cores, and the core wire having an outer diameter of up to about 500 µm can be applied to the batch fusion splicer. Is limited to For this reason, the outer diameter is 600 ~
When connecting the above-mentioned conventional type optical fiber core having a thickness of 900 μm, this one-time fusion splicer could not be used. The present invention has been made in view of the above circumstances, allows easy tapping of an optical fiber, can use an existing batch fusion splicer, has appropriate rigidity, and minimizes a handling loss. It is an object to provide an optical fiber core.

[0005]

The object of the present invention is to form an intermediate layer made of a resin having releasability on an optical fiber,
A coating layer made of a resin having a Young's modulus of 50 to 150 kgf / mm ² is provided thereon, and has an outer diameter of 450 to 550 μm.
It is solved by the optical fiber core. Further, it is preferable that the resin forming the coating layer is an ultraviolet curable resin.

[0006]

FIG. 1 shows an example of an optical fiber cable according to the present invention. In the figure, reference numeral 1 denotes an optical fiber bare wire, and a primary coating layer 2 and a secondary coating layer 3 made of an ultraviolet curable resin are sequentially provided on the outer periphery of the bare optical fiber to form an optical fiber wire 4. An intermediate layer 5 is provided on the outer periphery of the optical fiber 4, and a coating layer 6 is provided thereon to form the optical fiber 7. The outer diameter A of the bare optical fiber 1 is usually 125 μm, the outer diameter B of the optical fiber 4 is usually 250 μm, and the thickness of the intermediate layer 5 is 5 to 20 μm.
m, the thickness of the coating layer 6 is 95 to 140 μm, and the outer diameter C of the optical fiber is 450 to 550 μm.

As the bare optical fiber 1, a silica glass glass fiber or the like is usually used. In the primary coating layer 2,
Usually, a soft ultraviolet curable resin having a Young's modulus of 1 kg / mm ² or less is used. For the secondary coating layer 3, a hard ultraviolet curable resin having a Young's modulus of usually 50 kg / mm ² or more is used. The ultraviolet curable resin used for the primary coating layer 2 and the secondary coating layer 3 is a urethane acrylate, epoxy acrylate, polybutadiene acrylate,
It can be selected from silicone acrylate type, polyester acrylate type and the like.

The resin having releasability forming the intermediate layer 5 contains a silicone resin, and the effect of the silicone resin imparts releasability to the surface of the intermediate layer 5. This releasability refers to a layer (secondary coating layer 3 and coating layer 6) provided in close contact with the surface of the intermediate layer 5.
And the intermediate layer 5 are not bonded to each other and are easily separated.

As a raw material for forming the intermediate layer 5, a silicone resin is usually used in an amount of 0.5 to 4 in addition to the resin as the main component.
%, Preferably about 1 to 2% by weight. As the resin as the main component, a thermoplastic resin such as a polyethylene resin or a polypropylene resin, a phenol resin, an unsaturated polyethylene resin, a thermosetting resin such as a melamine resin, or an ultraviolet curable resin can be used. An ultraviolet curable resin is preferred because the thickness of the layer 5 can be easily controlled and the production speed can be increased, and is selected from urethane acrylate, epoxy acrylate, polybutadiene acrylate, silicone acrylate, polyester acrylate, and the like. can do. In particular, those which are generally used as a releasable coloring UV-curable ink are suitable as the raw material of the intermediate layer 5, and KSU455.
(Kansai Paint), Best Cure FR-1 (T &
KTOKA) can be used.

The resin used for the coating layer 6 preferably has a Young's modulus of 50 to 150 kg / mm 2. If the Young's modulus is less than 50 kg / mm2, handling loss due to lateral pressure or the like increases when handling the optical fiber for connection or the like. If the Young's modulus exceeds 150 kg / mm 2, the coating layer 6 may be formed in a low temperature environment of -40 ° C. or lower.
It is not preferable because the loss increases due to the side pressure due to the shrinkage of the material. The outer diameter of the coating layer 6 is desirably 450 to 550 μm. If the outer diameter is less than 450 μm, the mechanical strength becomes insufficient and the existing multi-core fusion machine cannot be used. The outer diameter is 550μ.
If it exceeds m, a multi-core fusion splicer cannot be used, and when an optical cable is formed by multiplying the optical fiber core, the cable outer diameter becomes too large, which is not preferable. It is also disadvantageous in terms of manufacturing cost.

After satisfying the above conditions, the coating layer 6
Thermoplastic resins such as polypropylene resin, phenolic resins, unsaturated polyethylene resins, thermosetting resins such as melamine resins, or UV-curable resins can be used as the resin for forming the UV-curable resin. It is also preferable in terms of speeding up. The UV-curable resin is particularly preferably an acrylate resin, and may be selected from urethane acrylate, epoxy acrylate, polybutadiene acrylate, silicone acrylate, polyester acrylate, and the like.

The optical fiber core wire 7 of this embodiment is formed, for example, by applying an uncured ultraviolet curable ink for coloring to the surface of the optical fiber wire 4 formed by a conventional method, and irradiating the ink with ultraviolet light to cure it. After forming the intermediate layer 5, an ultraviolet-curable resin liquid to be the coating layer 6 is applied thereon, and this is irradiated with ultraviolet rays, and the ultraviolet-curable resin liquid is cured to form the coating layer 6. Can be manufactured.

In the optical fiber core 7, an intermediate layer 5 having releasability is provided between the optical fiber 4 and the coating layer 6, so that the optical fiber 4 (intermediate layer 5 ), The coating layer 6 is easily peeled off. Further, the Young's modulus of the resin forming the coating layer 6 is set to 50 to 1
Since it is set sufficiently high at 50 kg / mm 2, the elongation of the coating layer 6 is small and the toughness is low, so that a notch can be easily formed with a tool such as a mechanical stripper. Therefore, the operation of peeling off the coating layer 6 is easy, and the optical fiber 4 can be exposed by neatly peeling the coating layer 6 as needed.

Further, since the Young's modulus of the coating layer 6 is in the above range, sufficient rigidity can be given to the optical fiber, and loss due to lateral pressure and the like when the optical fiber is handled for connection operation or the like. (Handling loss) can be minimized. Further, by setting the Young's modulus of the coating layer 6 within the above range, a suitable softness is given to the coating layer 6, and when the coating layer 6 is placed in a low-temperature environment of -40 ° C or lower, the coating layer shrinks to form the optical fiber 4. The applied stress can be reduced, and an increase in loss due to this stress can be suppressed.

Further, since the outer diameter of the coating layer 6 is set to 450 to 550 μm suitable for use in a multi-core fusion machine, a plurality of optical fiber cores can be used as it is by using the existing multi-core fusion machine. And can be easily fused together. In addition, if the intermediate layer 5 is formed from the ultraviolet curing ink for coloring and colored, the optical fiber 4 can be easily identified. Further, by using an ultraviolet curable resin as the resin for forming the coating layer 6, it is possible to increase the production speed.

[0016]

EXAMPLES Hereinafter, the effects of the present invention will be clarified by showing specific examples. (Examples 1 and 2 and Comparative Examples 1 to 3) Optical fiber core wires having the structure shown in FIG. 1 were manufactured by changing the resin for forming the coating layer 6. The common conditions in each of the examples and the comparative examples at this time are as follows. That is, the outer diameter A of the bare optical fiber 1 is 125 μm, and the outer diameter B of the optical fiber 4 is
Was 250 μm. The intermediate layer 5 is coated with an ultraviolet curable ink for coloring containing 2% by weight of a silicone resin (product name FR-1: manufactured by K & K, TOKA) on the optical fiber 4 and then irradiated with ultraviolet light. Formed by curing. The thickness of the intermediate layer 5 was 10 to 15 μm. Table 1 shows conditions that differ depending on the examples and comparative examples. Examples 1 and 2 relate to the present invention, and Comparative Examples 1 and 2 set the Young's modulus of the resin forming the coating layer 6 to a value other than the preferable range of 50 to 150 kg / mm 2. In Comparative Example 3, the coating layer 6 was formed from nylon similarly to the conventional one.

A notch is formed in the coating layer 6 at one end of the optical fiber core wire of each of the above examples by a mechanical stripper, and 100 mm of the coating layer 6 is peeled off from the notch at a time, and the optical fiber 4 is led out. I checked whether I could do it. As a result, when the coating layer 6 was completely peeled off and the optical fiber 4 was exposed,
Was left on the optical fiber 4 or could not be peeled off, and was evaluated as x. Also, two sets of five optical fiber cores of each example were prepared, and after tapping them, they were set in a multi-core fusion splicer and batch connection was attempted. The case where a defect occurred was evaluated as x.

Further, the increase in the loss during handling of the optical fiber core of each of the above examples was measured using the handling loss measuring device 10 of FIG. In this figure, the optical fiber cores 12, 12,... Pulled out from one end of each of two cables 11a, 11b having four or more optical fiber cores 12, 12,. The connection portions 12a are connected to each other, and the excess length portions 13 including the connection portions 12a are bundled and mounted on an excess length storage sheet 15 of the same type as that used for the closure.
Are stored in the extra-length storage sheet box 14. Some of the optical fiber cores 12, 12,... Drawn from the other end of one cable 11a are partially (plural).
7 connected to the light source 18 and other parts (multiple)
Are connected to an analyzing recorder 20 via a power meter 19.

Also, of the optical fiber cores drawn out from the other end of the other cable 11b, those connected to the core connected to the light source 18 and those connected to the core connected to the recorder 20. Are connected to each other at the folded portion 12b. As a result, a plurality of optical fiber core wires reach the folded portion 12 b from the light source 18 via the extra length portion 13, and further reach the analyzing recorder 20 via the extra length portion 13.

3 (a) to 3 (e) using the above measuring device.
As shown in the figure, a sheet 15 is taken out from the sheet box 14 in a state where light having a wavelength of 1.55 μm is incident from the light source 18 to the optical fiber cores 12, 12,. Is removed, the connection portion 12a of the removed core wire (operation core wire) is taken out of the sheet box 14, and then this core wire is attached to the sheet 15 again.
This sheet was stored in the sheet box 14. The loss at a wavelength of 1.55 μm of the core wire other than the operation core wire at this time was measured, and the increase in the loss is also shown in Table 1. In addition, in order to examine the temperature characteristics of the optical fiber cores of each of the above examples, the values at the wavelength of 1.55 μm of each optical fiber core were measured.
The loss at 40 ° C. was measured, and the increase was also shown in Table 1.

[0021]

[Table 1]

From the results in Table 1, it is found that the first embodiment according to the present invention
In the optical fiber core wire of No. 2, the increase in loss at the time of handling, the increase in loss at −40 ° C., the collective fusion property, and the tapping property all showed good values, whereas Comparative Examples 1 to 5.
In No. 3, it can be seen that the increase in loss at the time of handling, the increase in loss at −40 ° C., the collective fusion property, and the leadability were significantly inferior to those of the optical fiber core wires of Examples 1 and 2. .

[0023]

As described above, in the optical fiber core according to the present invention, since the intermediate layer having releasability is provided between the optical fiber and the coating layer, the coating layer is easily peeled off. Become. Further, the resin forming the coating layer has a Young's modulus of 5
Since it is set to a sufficiently high value of 0 to 150 kg / mm 2, the elongation of the coating layer is small and the toughness is low, and a notch can be easily formed with a tool such as a mechanical stripper. Therefore, the operation of peeling off the coating layer is easy, and the necessary amount of this coating layer can be peeled off so that the optical fiber can be exposed.

Further, since the Young's modulus of the coating layer is within the above range, sufficient rigidity can be given to the optical fiber, and loss due to lateral pressure or the like when the optical fiber is handled for connection operation or the like. (Handling loss) can be minimized. Further, by giving the coating layer a moderate softness by setting the Young's modulus of the coating layer to the above range,
When placed in a low temperature environment of −40 ° C. or lower, the stress applied to the optical fiber by contraction of the coating layer can be reduced, and an increase in loss due to this stress can be suppressed.

Further, since the outer diameter of the coating layer is set to 450 to 550 μm, which is suitable for use in a multi-core fusion machine, a plurality of optical fiber cores can be used as it is by using the existing multi-core fusion machine. And can be easily fused together. Further, by using an ultraviolet curable resin as a resin for forming the coating layer, the production speed can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an optical fiber core according to the present invention.

FIG. 2 is a schematic diagram showing a handling loss measuring system.

FIG. 3 is a process chart showing a procedure for measuring a handling loss.

[Explanation of symbols]

4 optical fiber, 5 intermediate layer, 6 coating layer

Claims (2)

[Claims] An intermediate layer made of a resin having releasability is formed on an optical fiber, and a Young's modulus of 50 to 50 is formed on the intermediate layer.
An optical fiber having a coating layer made of a resin of 150 kgf / mm ² and having an outer diameter of 450 to 550 μm. 2. The optical fiber core according to claim 1, wherein the resin forming the coating layer is an ultraviolet curable resin.