JPH0882726A - Optical fiber and coated optical fiber - Google Patents

Abstract

PURPOSE: To prevent volume change in a resin coating layer, changes in mechanical characteristics and decrease in adhesion strength between an optical fiber core and a coating layer due to an oil component by forming an oil-repellent layer as the outermost layer. CONSTITUTION: The optical fiber 7 is produced by forming a primary layer 9 on an optical fiber core 8 and further forming a secondary layer 10 and an oil-repellent layer 11 thereon. This oil-repellent layer 11 is formed by applying an oil-repellent agent. As for the oil-repellent agent, any polymer material having low surface energy such as various kinds of surfactants may be used, and especially, a material having good adhesion strength with the coating resin layer is preferable. The polymer material described above is usually prepared by dispersing or dissolving in a proper solvent for use. Thereby, by forming the oil-repellent layer 11, permeation of the oil component a jelly into inside of the optical fiber can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber element wire and an optical fiber core wire used in a jelly-filled optical fiber cable, and more particularly to an optical fiber element wire and an optical fiber core wire having excellent waterproofness.

[0002]

2. Description of the Related Art An optical fiber cable increases the optical transmission loss of the optical fiber and shortens its life due to the generation of hydrogen inside when water penetrates. Therefore, as one of the means for preventing the intrusion of water, a so-called loose material is one in which optical fiber strands or optical fiber ribbons are loosely stored in a loose tube and the gap is filled with a grease-like compound called jelly. It is used as a tube unit.

This jelly is generally composed of a petroleum-based base oil, silica for adjusting the consistency and sodium salt for adjusting the acid value. This loose tube unit is further covered, or several strands are twisted and then covered to form a so-called jelly-filled optical fiber cable. This jelly is useful not only for the purpose of waterproofing, but also for relaxing the impact and bending stress from the outside to prevent the optical transmission loss due to the micro vent of the optical fiber.

In such a loose tube unit, a plurality of optical fiber ribbons are laminated to form a laminated body having a rectangular cross section, which is arranged at the center of the loose tube, and a gap between the loose tube and the laminated body is formed. Is filled with jelly. A tension member is usually arranged between the loose tube and the laminated body.

The optical fiber ribbon used in the loose tube unit described above has a plurality of optical fiber strands formed by arranging a primary layer and a secondary layer on a bare optical fiber, which are arranged side by side to form a collective coating layer. It is formed by being fixed by. The primary layer, the secondary layer, and the collective coating layer are all made of UV curable resin or silicone resin. Hereinafter, the primary layer, the secondary layer, and the collective coating layer are collectively referred to as a coating resin layer.

Jerry is effective for waterproofing optical fiber cables and is inexpensive, so that it is often used for waterproof cables. But this jerry
As described above, since it contains petroleum-based oil as one of the components, it penetrates into the coating resin layer of the optical fiber for a long time and swells and deteriorates it. It penetrates even to the interface with the primary layer, peels off this interface, and causes obstacles such as increasing optical transmission loss particularly in a low temperature environment. It is considered that non-uniform strain is applied to the bare optical fiber due to partial peeling between the bare optical fiber and the primary layer, which causes loss due to microbending.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances, and prevents the jelly component from penetrating into the coating resin layer, thereby swelling the coating resin layer and the optical fiber. Providing optical fiber strands and optical fiber cores for jelly-filled optical fiber cables that prevent delamination between the bare wire and the primary layer, maintain waterproofness for a long time, and do not increase optical transmission loss The purpose is to do.

[0008]

This object can be solved by forming an oil repellent layer on the outermost layer of the optical fiber element wire or the optical fiber core wire. Further, the optical fiber core wire may be an optical fiber optical fiber tape core wire.

[0009]

In the optical fiber element wire or the optical fiber core wire of the present invention, the oil repellent layer is formed on the outermost layer thereof, so that the oil repellent layer prevents the oil component of the jelly from penetrating into the inside of the optical fiber. It

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the optical fiber strand for a jelly-filled optical fiber cable according to claim 1 will be described in detail. An example of the optical fiber strand is shown in FIG. The optical fiber bare wire 7 has a primary layer 9 on the bare optical fiber 8.
However, the secondary layer 10 is further formed thereon, and the oil repellent layer 11 is further formed thereon.

The oil-repellent layer 11 is formed by applying an oil-repellent agent and has a surface energy of 25 dyne / c.
It is preferably m or less. This is because when the surface energy exceeds 25 dyne / cm 2, the affinity with the oil component of jelly becomes high and the oil repellency effect cannot be exhibited.

The oil repellent may be any polymer material having a low surface energy, such as various surfactants, as long as it has oil repellency, but particularly good adhesion to the coating resin layer. It is preferably one. These polymeric materials are usually used after being dispersed or dissolved in an appropriate solvent.

Specific examples of the oil repellent include Daiflon (trade name, Daikin Industries, Ltd.) and Surflon C.
(Trade name, Asahi Glass Co., Ltd.) and other fluoroalkyl group-containing fluorosurfactants. This fluorine-based surfactant can be used by dispersing it in any solvent such as water, an organic solvent, or a mixed solution of water and an organic solvent, but one that does not mix with jelly oil preferable.

The thickness of the oil-repellent layer 11 made of such an oil-repellent agent can be any thickness depending on the type of the oil-repellent agent used and its physical properties, but is particularly 1 to 15 μm, and further 3 to 10 μm. Preferably there is. This is 1μ
This is because if it is m or less, the oil repellency cannot be sufficiently exhibited and the oil repellent layer 11 is more likely to be peeled from the secondary layer 10. Further, even if it exceeds 15 μm, the oil repellency is not greatly improved and it is wasted.

Such an oil repellent layer 11 is the secondary layer 1
It can be obtained by applying the above-mentioned oil repellent agent on the surface of No. 0 and forming a thin film made of the oil repellent agent. As a coating method, an arbitrary method such as a spray coating method or a die coating method can be used, and it is preferable that all of them are applied inline when the optical fiber element wire 7 is manufactured.

FIG. 2 shows an example of the loose tube unit 13 used in the jelly-filled optical fiber cable using the optical fiber element wire 7 as described above. This is one in which a plurality of the optical fiber strands 7 are bundled and loosely housed in the loose tube 4. A jelly 5 is filled between the optical fiber element wire 7 and the loose tube 4. Then, the loose tube unit 13 is further coated, or several loose strands are twisted and then coated to form a jelly-filled optical fiber cable.

Such an optical fiber strand 7 has a primary layer 9 and a secondary layer 10 on a bare optical fiber 8.
Since the oil repellent layer 11 is further formed thereon, the oil repellent layer 11 prevents the oil component of the jelly 5 from penetrating into the optical fiber.
It is possible to prevent a change in volume of the coating resin layer due to the oil content, a change in mechanical characteristics, a decrease in adhesion between the bare optical fiber 8 and the primary layer 9, and the like, and it is possible to maintain good optical characteristics for a long period of time.

Next, the optical fiber core wire for the jelly-filled optical fiber cable according to claim 2 will be described in detail. In this optical fiber core wire, a coating layer made of a resin such as nylon, Hytrel, or Teflon is formed on the optical fiber wire, and an oil repellent layer similar to the optical fiber wire 7 is formed on the coating layer. It will be.

Similar to the optical fiber elemental wire 7 described above, a plurality of the optical fiber core wires are bundled and loosely housed in a loose tube filled with jelly to form a loose tube unit. Then, the loose tube unit is further coated, or several strands are twisted and then coated to form a jelly-filled optical fiber cable.

Since such an optical fiber core wire has the oil repellent layer formed on the outermost layer, the oil repellent layer allows the oil component of jelly to enter the inside of the optical fiber, as in the case of the optical fiber bare wire 7. As a result, the mechanical properties are excellent, and good optical properties can be maintained for a long time.

Next, the optical fiber ribbon for the jelly-filled optical fiber cable according to claim 3 will be described in detail. An example of the optical fiber ribbon is shown in FIG. The optical fiber tape core wire 2 is formed by arranging a plurality of optical fiber element wires juxtaposed to each other and integrating them by a collective coating layer 12, and an oil repellent layer 11 is formed on the integrated one.

As shown in FIG. 4, a plurality of the optical fiber ribbons 2 are laminated to form a laminate 3 having a rectangular cross section, which is filled with jelly 5 and tension members 6 are provided in the vicinity of the inner peripheral edge. The loose tube unit 1 can be loosely housed in the loose tube 4 provided to form the loose tube unit 1. Then, as in the case of the optical fiber element wire 7 and the optical fiber core wire, the loose tube unit 1 is
Further coating, or several strands are twisted and then coated to form a jelly-filled optical fiber cable.

Since such an optical fiber tape core wire 2 has the oil repellent layer 11 formed on the outermost layer, it is formed by the oil repellent layer 11 like the optical fiber element wire 7 and the optical fiber core wire. Since the oil content of jelly is prevented from penetrating into the inside of the optical fiber, the mechanical properties are excellent and good optical properties can be maintained for a long period of time.

The present invention is not limited to the above example, and the oil repellent layer 11 is applied at 100 ° C. after applying the oil repellent.
It may be dried at the following low temperature. Furthermore, when an optical fiber cable is manufactured using the optical fiber element wire 7, the optical fiber core wire, the optical fiber tape core wire 2 and the like, the specific conditions such as the structure of the optical fiber cable and the composition of jelly are arbitrary. Is.

The effects of the present invention will be clarified below by showing concrete examples. Example 1 A primary layer 9 and a secondary layer 10 made of a UV curable resin are formed on a bare optical fiber 8 having a core diameter of 8 μm and a clad diameter of 125 μm, and an oil repellent layer 11 is further formed thereon. Thus, the optical fiber strand 7 was obtained. Then, this was put into the loose tube 4 to fabricate the loose tube unit 13 having the structure shown in FIG. The surface energy of the oil repellent layer 11 was adjusted to be 15 dyne / cm 2 by the contact angle method. Further, the void between the optical fiber element wire 7 and the loose tube 4 was filled with Syniofox # 415 as the jelly 5. Replace the loose tube unit 13 with 5
After leaving it in a constant temperature bath at 0 ° C. for 30 days, the transmission loss at 1.55 μm was measured. The results are shown in Table 1.

(Example 2) Surface energy is 25 dyne / c
A loose tube unit 13 similar to that of Example 1 was prepared except that the optical fiber element wire 7 having the m 2 oil repellent layer 11 formed thereon was used, and the same measurement was performed. The results are shown in Table 1.

(Example 3) Core diameter 8 μm, clad diameter 1
On the bare optical fiber 8 of 25 μm, on the optical fiber bare wire on which the primary layer 9 and the secondary layer 10 made of UV curable resin are formed, and on the optical fiber core wire on which the coating layer made of nylon 12 is further formed, An oil repellent layer composed of diflon and having a surface energy of 15 dyne / cm was formed. A loose tube unit similar to that in Example 1 was produced using such an optical fiber core wire, and the same measurement as in Example 1 was performed. The results are shown in Table 1.

(Embodiment 4) The surface energy is 25 dyne / c.
Other than using the optical fiber core wire formed with an oil repellent layer of m,
A loose tube unit similar to that in Example 3 was manufactured, and the same measurement was performed. The results are shown in Table 1.

(Example 5) Core diameter 8 μm, clad diameter 1
Four optical fiber element wires having a primary layer 9 made of a UV curable resin and a secondary layer 10 are juxtaposed on a bare optical fiber 8 of 25 μm, and these are put together by a collective coating layer 12 made of a urethane acrylate resin. After the integration, an oil repellent layer 11 made of Surflon S141 and having a surface energy of 15 dyne / cm was formed on the integrated optical fiber tape core wire 2. Then, four of the optical fiber optical fiber ribbons 2 were laminated to form a laminated body 3 to fabricate a loose tube unit 1 having a structure shown in FIG. Also, Synonyx # 29 as Jerry 5
0 was used. Then, the same measurement as in Example 1 was performed, and the results are shown in Table 1.

Example 6 Surface energy is 25 dyne / c
Loose tube unit 1 was prepared in the same manner as in Example 5 except that optical fiber ribbon 2 having m 2 oil repellent layer 11 was used, and the same measurement was performed. The results are shown in Table 1.

(Prior Art Example 1) The same loose tube unit as in Example 1 was prepared except that the oil repellent layer 11 was not formed. Similarly, the transmission loss at 1.55 μm was measured. The results are shown in Table 1.

(Conventional Example 2) A loose tube unit similar to that of Example 3 was prepared except that the oil repellent layer 11 was not formed. Similarly, the transmission loss at 1.55 μm was measured. The results are shown in Table 1.

(Conventional Example 2) A loose tube unit similar to that of Example 5 was prepared except that the oil repellent layer 11 was not formed. Similarly, the transmission loss at 1.55 μm was measured. The results are shown in Table 1.

Comparative Example 1 Surface energy is 30 dyne / c
A loose tube unit was prepared in the same manner as in Example 1 except that the oil repellent layer 11 of m 2 was formed, and the same measurement was performed. The results are shown in Table 1.

Comparative Example 2 Surface energy is 30 dyne / c
A loose tube unit was produced in the same manner as in Example 3 except that the oil repellent layer 11 of m 3 was formed, and the same measurement was performed. The results are shown in Table 1.

(Comparative Example 3) The surface energy is 30 dyne / c.
A loose tube unit was prepared in the same manner as in Example 5 except that the oil repellent layer 11 of m 2 was formed, and the same measurement was performed. The results are shown in Table 1.

[0037]

[Table 1]

[0038]

As described above, since the optical fiber element wire, the optical fiber core wire and the optical fiber tape core wire of the present invention have the oil repellent layer formed on the outermost layer, Since the oil content of jelly is prevented from penetrating into the inside of the optical fiber, the change in volume of the resin coating layer, the change in mechanical characteristics, and the decrease in the adhesive force between the bare optical fiber and the coating layer due to the oil content are prevented. it can. Therefore, it is possible to obtain an effect that good optical characteristics can be maintained for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an optical fiber element wire of the present invention.

FIG. 2 is a cross-sectional view showing an example of a loose tube unit using the optical fiber strand shown in FIG.

FIG. 3 is a sectional view showing an embodiment of the optical fiber optical fiber ribbon according to the present invention.

FIG. 4 is a cross-sectional view showing an example of a loose tube unit using the optical fiber ribbon of the optical fiber shown in FIG.

[Explanation of symbols]

1 ... Loose tube unit, 2 ... Optical fiber ribbon, 3 ... Laminated body, 4 ... Loose tube, 5 ... Jerry,
6 ... tension member, 7 ... optical fiber bare wire, 8 ... bare optical fiber, 9 ... primary layer, 10 ... secondary layer,
11 ... Oil repellent layer, 12 ... Collective coating layer

Claims (3)

[Claims] 1. An optical fiber element wire having an oil repellent layer formed on the outermost layer. 2. An optical fiber core wire, wherein an oil repellent layer is formed on the outermost surface layer. 3. The optical fiber core wire according to claim 2, wherein the optical fiber core wire is an optical fiber tape core wire.