JPH11202174A - Coated optical fiber tapes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To leave no resin waste on a ferruled bare optical fiber at the time of removing operation for a coating layer when a coated optical fiber tapes is connected. SOLUTION: The coated optical fiber tapes 6 has a <=50 g/mm drawing force between a bare optical fiber and a primary coating layer 2 of each of optical fibers 4, 4... constituting the ribbon 6 and 100 to 250% breaking elongation of the resin of the primary coating layer 2. Or the coated optical fiber tapes 6 has a >=50 g/mm drawing force and 150 to 250% breaking elongation of the resin of the primary coating layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber in which a primary coating layer and a secondary coating layer are formed on a bare optical fiber, and a plurality of the optical fiber strands are arranged in parallel and covered and integrated with a taped layer. The present invention is directed to an optical fiber tape core that is made so that when these coating layers are removed, resin dust does not remain on the bare optical fiber.

[0002]

2. Description of the Related Art FIG. 1 shows an example of an optical fiber ribbon, which has four optical fiber wires 4. The optical fiber ribbon 6 is formed by arranging optical fiber wires 4, 4,... In parallel, providing a tape layer 5 made of an ultraviolet curable resin or the like, and integrating them. As the optical fiber 4, two coating layers of a primary coating layer 2 and a secondary coating layer 3 made of an ultraviolet curable resin are provided on the circumference of the bare optical fiber 1.

When connecting these optical fiber ribbons 6, the primary coating layer 2, the secondary coating layer 3 and the taped layer 5 of each of the optical fiber wires 4 are peeled off and removed. It is necessary to dictate 1 ... In this case, a coating stripping tool such as a hot stripper is used, and the coating layers of the primary coating layer 2, the secondary coating layer 3, and the taped layer 5 are cut in a heated state, and these are collectively peeled off. Has been taken. FIG. 2 shows an example of the optical fiber ribbon 6 from which the respective coating layers have been removed and the bare optical fibers 1, 1.

[0004]

However, when the primary coating layer 2, the secondary coating layer 3, and the taped layer 5 of the optical fibers 4 are removed at one time, there are the following problems. That is, after the removal of these coating layers, the coating material of the coating layers cannot be completely removed, and as shown in FIG. 2, resin dust 7 may adhere to the bare optical fiber 1. This tendency is caused when the adhesive strength between the bare optical fiber 1 and the covering material is high, that is, the optical fiber ribbon 6.
Are connected to the bare optical fiber 1, 1,...
This was particularly evident when the pull-out force when pulling out was high. If such resin scraps 7 remain, it is necessary to remove them all from the bare optical fibers 1, 1... Before starting the connection work. The work of wiping and removing these resin wastes 7 has to be performed, which takes a great deal of trouble. Also,
By performing such work, the bare optical fiber 1
There is a possibility that the glass surface may be damaged, and there is a problem in the reliability of the strength of the connection portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent a resin debris from remaining on a bare optical fiber when removing a coating layer at the time of connecting an optical fiber ribbon. And

[0006]

According to the present invention, there is provided an optical fiber comprising a plurality of optical fiber strands each having a primary coating layer and a secondary coating layer formed around a bare optical fiber. In the case where the pull-out force between the bare optical fiber and the coating layer of each of the optical fibers constituting the optical fiber ribbon is not more than 50 g / mm in the optical fiber ribbons which are arranged in parallel and collectively covered with the taped layer. To
The elongation at break of the resin used for the primary coating layer of the optical fiber was set to 100 to 250%. When the pulling force between the bare optical fiber and the coating layer was 50 g / mm or more, the elongation at break of the resin used for the primary coating layer of the optical fiber was 150 to 250%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As a result of various studies, the present inventors have found that the primary coating layer, the secondary coating layer, and the taped layer of the optical fiber are collectively removed and the resin dust remains on the bare optical fiber because of the secondary coating layer and the tape. It has been found that, regardless of the properties of the resin used for the layer, it is related to the elongation at break of the resin used for the primary coating layer of the optical fiber. By adjusting the elongation at break of the resin of the primary coating layer of the optical fiber according to the pull-out force, an optical fiber ribbon that does not leave resin debris on the bare optical fiber even after the coating layer is removed can be obtained. I got it.

As an example of the optical fiber ribbon of the present invention, one having a structure similar to that shown in FIG. 1 can be mentioned. The present invention relates to an optical fiber tape in which a plurality of optical fiber wires 4 each having a primary coating layer 2 and a secondary coating layer 3 formed on the circumference of an optical fiber bare wire 1 are arranged in parallel and collectively covered with a taped layer 5. In the core wire 6, each of the optical fiber wires 4 and 4 constituting the optical fiber tape core wire 6
When the pulling force between the bare optical fiber 1 and the primary coating layer 2 is 50 g / mm or less, the elongation at break of the resin used for the primary coating layer 2 of the optical fiber 4 is reduced to 1
Adjusted to 100 to 250%, and the pulling force is 50 g / mm.
In the above case, the elongation at break of the resin used for the primary coating layer 2 of the optical fiber 4 is adjusted to 150 to 250%.

The pulling force between the bare optical fiber 1 and the primary coating layer 2 is determined by a measuring method as shown in FIG. First, as shown in FIG. 3A, a plate 10 having a guide groove 11 having a length of about 5 mm is prepared. Next, as shown in (B), the tip of the optical fiber 4 is fixed to the guide groove 11 with an adhesive such as α-cyanoacrylate or epoxy. Then, as shown in FIG. 3C, the portion of the fixed optical fiber 4 near the plate 10 is cut so that only the coating layer on the outer peripheral portion is cut so as not to reach the bare optical fiber 1. Then, a cut is made with a razor 13 or the like. Then, as shown in (D), the optical fiber 4 is pulled out at a speed of 3 mm /
min, the coating layer of the optical fiber 4 is removed at once, and the bare optical fiber 1 is exposed. And
The pulling force applied at this time is measured. The pulling force between the bare optical fiber and the primary coating layer in the present invention is the pulling force required at this time.

In other words, the pulling force indicates the adhesion between the bare optical fiber 1 and the primary coating layer 2, and it can be said that the stronger the force, the greater the pulling force. Also, the stronger this force, the more the resin dust 7 tends to remain on the bare optical fiber 1 after removing the coating layer. According to the present invention, the elongation at break of the resin used for the primary coating layer 2 of the optical fiber 4 is adjusted according to the pulling force.

The breaking elongation of the resin is 0.2 m in film thickness.
m, a sample is prepared by cutting the resin sheet into a width of 10 mm, and the tensile strength is defined as the elongation percentage when the resin sheet is broken when the sample is pulled when the sample is pulled at 50 mm / min.

When the drawing force is 50 g / mm or less, the elongation at break of the resin used for the primary coating layer 2 is preferably in the range of 100 to 250%. The elongation at break of the resin used for the primary coating layer 2 is within the above range, and the pulling force between the bare optical fiber 1 of each optical fiber 4 and the primary coating layer 2 is 50 g / mm.
In the case of smaller than the following, the optical fiber ribbon 6
Is manufactured, and when these coating layers are collectively removed, the resin dust 7 can be prevented from remaining on the bare optical fibers 1, 1,....

When the drawing force is 50 g / mm or more, the breaking elongation is preferably in the range of 150 to 250%. Within this range, the resin dust 7 does not remain on the bare optical fiber 1 even when the pulling force of each optical fiber 4 is as high as 50 g / mm or more.

As the resin used for the primary coating layer 2, an ultraviolet curable resin such as urethane acrylate, epoxy acrylate, or silicon acrylate, which is generally used as a coating material for an optical fiber, is used.
At this time, the Young's modulus of the resin used for the primary coating layer 2 is in the range of 0.05 to 0.3 kg / mm ² , and the film thickness and the like are preferably set as appropriate, and are not particularly limited.

As the secondary coating layer 3 of the optical fiber 4, similarly to the primary coating layer 2, an ultraviolet curable resin such as urethane acrylate, epoxy acrylate, or silicon acrylate, which is generally used as a coating material for an optical fiber, is used. . The Young's modulus of the resin used for the secondary coating layer 3 is in the range of 10 to 200 kg / mm ² , and the film thickness and the like are preferably set appropriately, and are not particularly limited.

As a method for manufacturing the optical fiber 4, the bare optical fiber 1 obtained by melt-spinning the optical fiber preform is used.
Then, an ultraviolet-curable resin liquid used for the primary coating layer 2 whose elongation at break was adjusted as described above was applied, and this was cured to form the primary coating layer 2, on which the secondary coating layer 3 was formed. A commonly used method of forming a secondary coating layer 3 by applying and curing an ultraviolet curable resin liquid to be used may be used. In addition, the primary coating layer 2
Alternatively, a two-layer batch coating method in which the secondary coating layer 3 is collectively applied over two layers and cured may be used.

The optical fiber ribbon 6 of the present invention is obtained by aligning a plurality of the above-described optical fiber wires 4 in a row in parallel, collectively covering them with a tape layer 5, and integrating them. As the tape layer 5, an ultraviolet curable resin such as urethane acrylate, epoxy acrylate, or silicon acrylate is used. It is desirable that the Young's modulus of the resin used for the tape layer 5 is slightly smaller than that of the secondary coating layer 3 of the optical fiber 4. The film thickness and the like are preferably set as appropriate, and are not particularly limited. As a method of manufacturing the optical fiber ribbon 6, an ultraviolet curable resin liquid used for the tape layer 5 of the optical fiber wires 4, 4,... Normal methods are used.

As described above, in the optical fiber ribbon 6 of the present invention, the elongation at break of the resin used for the primary coating layer 2 is adjusted according to the pull-out force.
In the tapping operation at the connection, the resin waste 7 does not remain on the bare optical fiber 1 after the removal of the coating layer. Therefore, troublesome work of removing the resin dust 7 at the time of the connection work becomes unnecessary, the connection work proceeds smoothly, and the surface of the bare optical fiber 1 is not damaged.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The resin used for the primary coating layer 2 of the optical fiber 1 is urethane acrylate having a Young's modulus of 1.1 to 0.15 kg / mm ² , and the resin used for the secondary coating layer 3 is a Young's modulus of 60 to 70 kg / mm ^2. mm ² urethane acrylate, optical fiber ribbon 6
As the resin used for the taped layer 5, a Young's modulus of 50 to
The breaking elongation of the primary coating layer 2 was changed as shown in Table 1 using urethane acrylate of 60 kg / mm ² , and the four-core optical fiber ribbons 6 of Examples 1 to 3 and Comparative Examples 1 to 3 were used. Was prepared. Using these optical fiber tape cores 6, the coating layer of the optical fiber was drawn out and removed in the following manner. The pulling force at that time and the residual resin dust of the bare optical fiber 1 after the removal were examined, and the coating removal characteristics of each optical fiber tape were evaluated.

First, 5 mm from the tip of each strand 4 constituting each optical fiber ribbon 6 of Examples 1-3 and Comparative Examples 1-3.
3A is fixed to a plate-like rubber piece as shown in FIG. 3A with an epoxy resin, and an optical fiber is coated on the coating layer of each of the wires 4 constituting the optical fiber ribbon 6 near the fixed portion. A cut was made with a razor so that the bare wire 1 was not damaged. Then, the fixing portion was fixed with an epoxy-based adhesive, and the coating layer of each strand 4 constituting the optical fiber ribbon 6 was pulled out. The drawing speed at this time is 3 mm / m
The withdrawal force at this time was measured as in, and shown in Table 1.

As for the evaluation of the coating removal characteristics, the coating layer of each of the wires 4 constituting the optical fiber ribbon 6 was removed at once using a hot stripper as shown in FIG. 4 optical fiber bare wires 1, 1 ...
Observe with a microscope 20mm from the tip of
This was performed by counting the number of resin chips. At this time,
As resin dust 7, those having a size of 5 μm or more, which are considered to have an effect on fusion splicing of optical fibers, were counted.
Then, those in which the resin waste 7 remained were evaluated as x, and those in which the resin waste 7 did not remain were evaluated as o. Table 1 shows the results.

[0022]

[Table 1]

From these results, it can be seen that in the embodiment of the present invention, no resin dust 7 remains on the bare optical fiber 1 after the coating layer is removed, and good coating removal characteristics can be obtained. Further, in Comparative Example 3, although the breaking elongation of the resin was 135%, which is the optical fiber wire 4 according to the first aspect, since the drawing force was as high as 85 g / mm, it is assumed that the resin debris remained. . In this case, as described in claim 2, it is understood that the elongation at break of the resin needs to be 150% or more.

[0024]

As described above, in the optical fiber ribbon of the present invention, the elongation at break of the resin used for the primary coating layer is adjusted in accordance with the pulling force. No resin waste remains in the bare optical fiber after the layer is removed. Therefore, troublesome work of removing resin dust at the time of connection work becomes unnecessary, the connection work proceeds smoothly, and the surface of the bare optical fiber is not damaged.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an optical fiber tape cord.

FIG. 2 is a schematic configuration diagram showing an example of an optical fiber tape cord after a coating layer is removed.

FIG. 3 is a schematic process diagram showing steps of a method for measuring a pulling force between a bare optical fiber and a primary coating layer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... bare optical fiber, 2 ... primary coating layer, 3 ... secondary coating layer 4 ... optical fiber strand, 5 ... taped layer, 6 ... optical fiber tape core wire 7 ... resin waste

Claims (2)

[Claims] 1. An optical fiber ribbon in which a plurality of optical fiber wires each having a primary coating layer and a secondary coating layer formed on the circumference of an optical fiber bare wire are arranged in parallel and collectively covered with a taped layer. The pull-out force between the bare optical fiber and the primary coating layer of each optical fiber constituting the optical fiber ribbon is 50 g / mm or less, and the resin used for the primary coating layer of the optical fiber is not used. Elongation at break is 100-25
An optical fiber ribbon comprising 0%. 2. An optical fiber ribbon, in which a plurality of optical fiber wires each having a primary coating layer and a secondary coating layer formed on the periphery of an optical fiber bare wire are arranged in parallel and collectively coated with a taped layer, The pull-out force between the bare optical fiber and the primary coating layer of each optical fiber constituting the optical fiber tape is 50 g / mm or more, and the resin used for the primary coating layer of the optical fiber is used. Breaking elongation is 150-25
An optical fiber ribbon comprising 0%.