JP2001242360A - Method for manufacturing optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the exfoliation of an outer layer by improving the adhesion property between the inner layer and outer layer of an optical fiber provided with the inner layer and outer layer consisting of UV curing resins on a wire- shaped medium. SOLUTION: The UV curing resin which constitutes the inner layer 19 is applied on a wire-like body, such as an internally coated wire-like body 5, and while this wire-like body is passed through the inside of a wire-like passage 7c in which the air in a UV irradiation furnace 7 passes and further while the wire-like body is passed through the inside of a wire-like passage 8c in which the gaseous nitrogen in a UV irradiation furnace 8 passes, the wire-like body is irradiated with UV rays to form the inner layer 19 not completely cured on the surface. The UV curing resin which constitutes the outer layer 20 is thereafter applied on the inner layer 19 and while this wire-like body is passed through the inside of a wire-like passage 12 in which the air in a UV irradiation furnace 12 passes, by which the outer layer 20 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber having an inner layer and an outer layer made of a UV-curable resin, in which the peeling of the outer layer is improved.

[0002]

2. Description of the Related Art In connection between a submarine optical fiber cable and a repeater, there is an optical fiber used in a portion called a feedthrough which is a penetrating portion of an airtight partition. FIG. 2 is a cross-sectional view showing an example of an optical fiber for feed-through, in which 21 is a glass fiber, 22 is a primary coating layer made of a polyimide resin, 23 is a secondary coating layer made of an ultraviolet curing resin, and 24 is An inner coating layer, 25 is an inner layer made of an ultraviolet curable resin, 26 is an outer layer made of an ultraviolet curable resin, and 27 is an optical fiber.

The optical fiber 27 is made of a glass fiber 2
1, a primary coating layer 22 made of a polyimide resin, a secondary coating layer 23 made of an ultraviolet curable resin, an inner layer 25,
An outer layer 26 provided with three coating layers,
An optical fiber with excellent heat resistance. The outer diameter of the glass fiber 21 is about 125 μm, the outer diameter of the primary coating layer 22 is about 140 μm, and the outer diameter of the secondary coating layer 23 is 180 μm.
The outer diameter of the inner layer 25 is about 245 μm,
Has an outer diameter of about 250 μm, and the outer layer 26 is colored by adding a coloring agent for identification of the optical fiber 27.

[0004] This optical fiber is manufactured by the manufacturing process shown in FIG. 3A is a diagram illustrating a polyimide coating process, FIG. 3B is a diagram illustrating an ultraviolet curable resin layer coating process, and FIG. 3C is a diagram illustrating a coloring layer coating process. 31 is an optical fiber base material, 32 is a heater, 33 and 35 are polyimide resin coating devices, 34 and 36
Is a heating furnace, 37 is a reel, 38 and 40 are ultraviolet curing resin coating devices, 39 and 41 are ultraviolet irradiation furnaces, 42 is a reel, 43 is an ultraviolet curing resin coating device, 44 is an ultraviolet irradiation furnace, and 45 is a reel. is there.

First, in the polyimide resin coating step shown in FIG.
The glass fiber 21 is drawn by heating under the above conditions, and a primary coating layer made of a polyimide resin is provided on the glass fiber 21 twice. The polyimide resin layer is applied with a resin in polyimide resin coating devices 33 and 35, and heated in a heating furnace 34 or 36.
In the stage where the primary coating layer made of a polyimide resin is formed, it is usually wound once on a reel 37 once.

In the ultraviolet curing resin coating step shown in FIG. 3B, a secondary coating layer and an inner layer made of the ultraviolet curing resin are provided on the line drawn from the reel 37 twice. The resin is applied by ultraviolet curing resin application devices 38 and 40, and the resin is cured by irradiating ultraviolet rays in an ultraviolet irradiation furnace 39 or 41, respectively, and wound on a reel 42. In the colored layer coating step of FIG. 3C, an ultraviolet curable resin containing a colorant is applied by a UV curable resin coating device 43 on the line drawn out from the reel 42, and the ultraviolet irradiation furnace 4 is used.
At 4, ultraviolet rays are irradiated and cured to form an outer layer to form an optical fiber 27, which is wound around a reel 45.

Since the ultraviolet irradiation furnaces 39, 41 and 44 have substantially the same structure, an example of the ultraviolet irradiation furnace 41 for curing the inner layer will be described. FIG. 4 is a detailed view of the ultraviolet irradiation furnace 41, wherein 41a is an ultraviolet lamp, 41b
Is a mirror, 41c is a linear body passage, 41d is a nitrogen gas supply device, 41e is a gas pipe, and 46 is a linear body coated with resin. Ultraviolet rays emitted from the ultraviolet lamp 41a are irradiated directly or via a mirror 41b onto the linear body 46 passing through the linear body passage 41c transmitting the ultraviolet rays, thereby curing the coating resin layer of the linear body 46. Further, a nitrogen gas is supplied from the nitrogen gas supply device 41d into the linear body passage 41c through the gas pipe 41e, the nitrogen gas is caused to flow into the linear body passage 41c, and the coating resin layer of the linear body 46 which is irradiated with ultraviolet rays. Is not exposed to oxygen in the air, thereby blocking oxygen in the air that inhibits the curing reaction of the resin.

[0008]

At the feed-through portion at the connection with the repeater, the work of passing an optical fiber through a small hole is involved, and the surface of the optical fiber is rubbed with fingers or other members. There are many. On the surface of the optical fiber, there is an outer layer 26 made of a UV-curable resin to which a coloring agent is added. This outer layer is as thin as several μm, and when the optical fiber is rubbed by touching other members, the Outer layer 26
May come off. In addition, since the outer layer 26 is colored, when it is peeled, the inner layer is exposed and mottled, resulting in an ugly appearance. SUMMARY OF THE INVENTION The present invention provides a method for manufacturing an optical fiber that can reduce peeling of an outer layer.

[0009]

According to a method of manufacturing an optical fiber of the present invention, an ultraviolet curing resin serving as an inner layer is applied on a linear body, and then air in an ultraviolet irradiation furnace flows. UV rays are irradiated while passing through the linear body passage, and furthermore, the inner layer is formed by irradiating ultraviolet rays while passing through the linear body passage through which the nitrogen gas in the UV irradiation furnace flows. The outer layer is formed by applying an ultraviolet curing resin to be the outer layer on the inner layer and irradiating ultraviolet rays while passing the ultraviolet curing resin through the linear body passage in the ultraviolet irradiation furnace where nitrogen gas flows. Is what you do. Further, in the present invention, when a linear body is referred to without any particular description, it includes any of a bare glass fiber, a primary coated linear body, and an internal coated linear body.

[0010] Thus, while the surface portion of the ultraviolet-curable resin layer serving as the inner layer remains in a semi-cured state and has a tacky state, portions other than the surface are cured, and the outer layer and the outer layer are further cured. By applying an ultraviolet curable resin and curing the resin, the adhesion between the inner layer and the outer layer is improved, so that the outer layer is hardly peeled off.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a view for explaining a coating step for forming a part of an inner coating layer and an inner layer in an embodiment of a method for manufacturing an optical fiber of the present invention, and FIG. FIG. 1C is a cross-sectional view illustrating an example of an optical fiber manufactured by an optical fiber manufacturing method according to an embodiment of the present invention. .

In FIG. 1, 1 is a reel, 2 is a primary coated linear body, 3, 6, and 11 are ultraviolet curable resin coating devices,
a, 6a, and 11a are ultraviolet curable resin supply devices, 3b,
6b, 11b are resin supply pipes, 4, 7, 8, 12 are ultraviolet irradiation furnaces, 4a, 7a, 8a, 12a are ultraviolet lamps,
b, 7b, 8b, 12b are mirrors, 4c, 7c, 8c,
12c is a linear passage, 4d, 8d, 12d is a nitrogen gas supply device, 7d is a clean air supply device, 4e, 7e, 8e,
12e is a pipe, 5 is an inner coated linear body, 9 is an inner coated linear body, 10 is a reel, 13 is an optical fiber, 14 is a reel, 15 is a glass fiber, 16 is a primary coating layer, and 17 is a secondary coating. Layers, 18 is an inner coating layer, 19 is an inner layer, and 20 is an outer layer.

The primary coated linear body 2 is made of a glass fiber 15
On which a primary coating layer 16 made of a polyimide resin is provided. The inner covering linear body 5 is provided with a secondary covering layer 17 made of an ultraviolet curable resin on the primary covering linear body 2. Further, the primary coating layer 16 and the secondary coating layer 17 are combined to form an internal coating layer 18. Therefore, it can be said that the inner coating linear body 5 has the inner coating layer 18 provided on the glass fiber 15. The inner layer-coated linear body 9 is
An inner layer 19 made of an ultraviolet curable resin is provided on the inner covering linear body 5.

The optical fiber 13 has an outer layer 20 made of an ultraviolet-curable resin provided on the inner layer-coated linear body 9. The optical fiber 13 is an example of an optical fiber having high heat resistance used in a place called a feed-through. However, in the case of an optical fiber for other uses, the inner coating layer is formed only by a layer of an ultraviolet curable resin. Sometimes it is.

Although not shown in FIG. 1 in manufacturing the optical fiber 13, first, a glass fiber is formed by a process similar to the above-described polyimide resin coating process of FIG. 15 is provided with a primary coating layer 16 made of a polyimide resin on
Prepare Then, as shown in FIG.
From the primary coated linear body 2 and the primary coated linear body 2
The secondary coating layer 17 and the inner layer 19 are formed thereon.

In forming the secondary coating layer 17, an ultraviolet-curable resin is supplied from the ultraviolet-curable resin supply device 3a to the ultraviolet-curable resin coating device 3 through the resin supply pipe 3b. Then, the ultraviolet-curable resin is applied to the surface of the primary coated linear body 2. And
While the linear body coated with the resin is passed through the linear body passage 4c of the ultraviolet irradiation furnace 4, ultraviolet rays are irradiated directly from the ultraviolet lamp 4a or through the mirror 4b to be cured to cure the secondary coating layer 17. It is formed as the internally coated linear body 5. In the linear passage 4c, a pipe 4e is provided from the nitrogen gas supply device 4d.
Through which nitrogen gas is supplied so that the line being irradiated with ultraviolet rays does not come into direct contact with air. The steps so far are the same as the steps according to the prior art shown in FIG.

Next, when forming the inner layer 19,
A method different from the prior art is adopted as follows. FIG.
As shown in (A), the inner-coated linear body 5 is passed through an ultraviolet-curable resin coating device 6 to apply a normal natural color ultraviolet-curable resin to be the inner layer 19. The UV-curable resin is supplied from the UV-curable resin supply device 6a to the resin supply pipe 6b.
To the ultraviolet-curable resin coating device 6. Next, while the linear body coated with the resin is passed through the linear body passage 7c of the ultraviolet irradiation furnace 7 and the linear body passage 8c of the ultraviolet irradiation furnace 8, the ultraviolet lamp 7a or 8a directly or the mirror 7b. , 8b. At the same time, air is circulated in the linear passage 7c from the clean air supply device 7d through the pipe 7e. Then, nitrogen gas is circulated in the linear passage 8c from the nitrogen gas supply device 8d through the pipe 8e.

Thus, while the linear body coated with the ultraviolet curable resin serving as the inner layer passes through the linear body passage 7c, the linear body passes through the air while the linear body passes through the linear body passage 8c. Is exposed to an atmosphere of nitrogen gas. Therefore, in the ultraviolet irradiation furnace 7, since the resin is irradiated with ultraviolet rays in the presence of oxygen in the air, the curing of the resin surface is inhibited by the oxygen and does not proceed. Since there is no contact, curing proceeds relatively. In addition, the surface and the inside of the resin are gradually cured by being irradiated with ultraviolet rays in the ultraviolet irradiation furnace 8, but even after passing through the ultraviolet irradiation furnace 8, the surface portion of the inner layer is semi-cured and becomes tacky. In the state of having, the inside other than the surface is in a fully cured state.

Thereafter, as shown in FIG. 1 (B), an ultraviolet curable resin containing a colorant, which becomes the outer layer 20, is supplied from the ultraviolet curable resin supply device 11a through a resin supply pipe 11b. And the ultraviolet curable resin is applied on the inner layer 19 of the inner layer-coated linear body 9 by the ultraviolet curable resin coating device 11. The linear body coated with the resin is moved to the linear body passage 12 c of the ultraviolet irradiation furnace 12.
Ultraviolet light is irradiated directly from the ultraviolet lamp 12a or through the mirror 12b during the passage through the inside.

At the same time, nitrogen gas is circulated in the linear passage 12c from a nitrogen gas supply device 12d through a pipe 12e. This forms a cured outer layer 20 on the inner layer 19. In addition, the surface of the inner layer 19 is formed in a semi-cured and tacky state, and the outer layer 20 is formed thereon. Playing a role, the inner layer 19 and the outer layer 20 are firmly adhered. Although FIGS. 1A and 1B show an example in which the inner layer and the outer layer are formed in separate steps, both may be formed in a continuous step.

[0021]

EXAMPLE As an example, an optical fiber was manufactured by the manufacturing method according to the present invention shown in FIGS. 3 (A), 1 (A) and 1 (B). The outer diameter of the glass fiber 15 is 125 μm, the outer diameter of the primary coating layer 16 is 140 μm, the outer diameter of the secondary coating layer is 180 μm, and the outer diameter of the inner layer is 245 μm.
m, and the outer diameter of the outer layer was 250 μm. Further, as a comparative example, an optical fiber having the same size as that of the example was manufactured by the manufacturing method according to the related art shown in FIGS. 3A, 3B and 3C.

With respect to the optical fibers of the examples and the comparative examples, the peeling state of the outer layer was examined by the following test method. FIG. 5 is a front view of an apparatus for testing the peeling of the outer layer, where 51 is an optical fiber to be measured, 52 is a table, 53
Is a moving object, 54 is a pulley, 55 is a weight, and 56 is a locking portion. The moving object 53 has a width W of 30 mm and a height H of 1
5 mm, R at both corners is 5 mm, and the upper surface is Ra = 20 μ
m, a steel object having a rough surface and a width D
= 20 mm and slides back and forth. Load W of weight 55
(N) can be changed variously.

One end of the optical fiber 51 to be measured is locked at a locking point 56 on the table 52, a weight 55 is connected to the other end, and a pulley 54 is provided across the moving object 53 placed on the table 52. The weight 55 is suspended, and tension is applied to the measured optical fiber 51. Note that L is 150 mm. In this state, the moving object placed at the center of L is reciprocated once with a width of D = 20 mm.

Thereafter, the measured optical fiber 51 is removed, and
The degree of peeling of the outer layer is visually inspected. If there is no peeling and lifting of the outer layer, it is `` good '', if there is no peeling of the outer layer, but `` floating '' is `` middle '', and if there is peeling of the outer layer. It is determined as "defective". Table 1 shows that each of the optical fibers of Examples and Comparative Examples was 10
It is a test of each book and the results are summarized. The fraction display indicates the ratio of the number of samples for each of “good”, “middle”, and “bad”.

[0025]

[Table 1]

According to Table 1, in the optical fiber of the embodiment,
Even when the load is 5.0 N, the outer layer does not peel off, but in the optical fiber of the comparative example, the outer layer peels off when the load is 2.0 N. Therefore, in the optical fiber of the example, the peeling of the outer layer was clearly reduced as compared with the optical fiber of the comparative example, and the adhesion between the outer layer and the inner layer was improved in the optical fiber of the example. Can be confirmed.

[0027]

According to the method of manufacturing an optical fiber of the present invention, an ultraviolet curable resin serving as an inner layer is applied on a linear body, and then the resin is passed through a linear body passage through which air flows. Irradiate with ultraviolet rays, further irradiate with ultraviolet rays while passing through the linear body passage in which nitrogen gas flows, to form an inner layer,
Thereafter, an ultraviolet-curable resin serving as an outer layer is applied on the inner layer, and the outer layer is formed by irradiating ultraviolet rays while passing the resin through a linear body passage through which nitrogen gas flows. is there. Thus, the surface of the ultraviolet-curable resin layer serving as the inner layer is left in a semi-cured state, and the ultraviolet-curable resin serving as the outer layer is applied thereon and the resin is cured, whereby the inner layer and the outer layer are cured. It is possible to manufacture an optical fiber in which the outer layer is hardly peeled off by improving the adhesion to the layer.

The optical fiber manufactured by the method for manufacturing an optical fiber according to the present invention can be used in a place where handling such as rubbing of a coated surface such as a field-through place can be performed. Peeling is unlikely to occur. When the outer layer contains a coloring agent, the colored layer does not come off, so that the appearance can be maintained. Further, the method for producing an optical fiber of the present invention is not only an optical fiber having an inner coating layer consisting of a primary coating layer of a polyimide resin and a secondary coating layer of an ultraviolet curable resin, but also a glass fiber having no inner coating layer. The present invention can be applied to the production of the most general optical fiber having an inner layer made of an ultraviolet-curable resin and an outer layer made of an ultraviolet-curable resin.

[Brief description of the drawings]

FIG. 1A is a diagram illustrating a coating step of forming a part of an inner coating layer and an inner layer in an embodiment of an optical fiber manufacturing method according to the present invention, and FIG. 1B is an optical fiber manufacturing method according to the present invention. Coating process explanatory diagram for forming the outer layer in the embodiment of the
(C) is a cross-sectional view showing one example of an optical fiber manufactured by the optical fiber manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing an example of an optical fiber for feed-through.

3A and 3B are diagrams illustrating a manufacturing process of an optical fiber according to a conventional technique, wherein FIG. 3A is a diagram illustrating a polyimide coating process, FIG. 3B is a diagram illustrating an ultraviolet curable resin layer coating process, and FIG. () Is a diagram illustrating a colored layer covering step.

FIG. 4 is a view showing an example of a conventional ultraviolet irradiation furnace.

FIG. 5 is a front view of an apparatus for testing the peeling of an outer layer.

[Explanation of symbols]

 1: Reel 2: Primary coated linear body 3, 6, 11: UV curable resin coating device 3a, 6a, 11a: UV curable resin supply device 3b, 6b, 11b: Resin supply pipe 4, 7, 8, 12 : UV irradiation furnace 4a, 7a, 8a, 12a: UV lamp 4b, 7b, 8b, 12b: Mirror 4c, 7c, 8c, 12c: Linear passage 4d, 8d, 12d: Nitrogen gas supply device 7d: Clean air supply Apparatus 4e, 7e, 8e, 12e: Piping 5: Inner coated linear body 9: Inner layer coated linear body 10: Reel 13: Optical fiber 14: Reel 15: Glass fiber 16: Primary coating layer 17: Secondary coating layer 18: inner coating layer 19: inner layer 20: outer layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H050 BA11 BA18 BA32 BB06Q BB33S BC03 4G060 AA01 AA03 AC12 AC15 AC18 AD24 AD43

Claims (2)

[Claims] 1. An ultraviolet-curable resin serving as an inner layer is applied on a linear body, and then ultraviolet rays are irradiated while passing through a linear body passage through which air in an ultraviolet irradiation furnace flows. ,
Further, ultraviolet rays are irradiated while passing through a linear passage in which a nitrogen gas flows in an ultraviolet irradiation furnace to form an inner layer, and then, an ultraviolet curable resin serving as an outer layer is applied on the inner layer. A method for producing an optical fiber, comprising: irradiating ultraviolet rays while passing it through a linear passage through which nitrogen gas flows in an ultraviolet irradiation furnace to form an outer layer. 2. The linear body is formed by applying an inner coating layer composed of a primary coating layer made of a polyimide resin on a glass fiber and a secondary coating layer made of an ultraviolet curable resin provided thereon. The method according to claim 1, wherein the ultraviolet curable resin serving as the outer layer contains a coloring agent.