JPH0412484Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention does not increase transmission loss in low and high temperature ranges, does not deteriorate mechanical properties such as bending resistance and impact resistance, and can be used from low to high temperatures. The present invention relates to an optical fiber cord that can be used over a wide temperature range.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, various configurations have been proposed for optical fiber cords, but generally, as shown in FIG. 2, an optical fiber wire 1 consisting of a core and a cladding is used.
A silicone resin layer 2 and a polyamide resin layer 3 are sequentially extruded and coated around the outer periphery of the wafer, and a tension member layer made of, for example, Kevlar (polyaramid fiber (trade name of EIDUPONT)) is further formed around the outer periphery of the polyamide resin layer 3. A soft vinyl chloride resin layer 5 is disposed on the outside as a protective coating (envelope).

However, with such conventional optical fiber cords, the operating environment temperature of the optical fiber cords is
When the temperature exceeds 80℃, the soft vinyl chloride resin layer 5 of the outer cover
Since the internal polyamide resin layer 3 softens, it cannot be used at high temperatures of 80°C or higher, or -10°C.
At lower temperatures, these resin layers lose their elasticity, resulting in problems such as an increase in transmission loss of the optical fiber 1 and a deterioration in mechanical properties that can withstand bending and impact.

As a result of many research experiments, the inventors of the present invention devised an optical fiber cord as shown in FIGS. 3 and 4 in order to improve the shortcomings of the conventional optical fiber cord. No. 137286). Briefly speaking, the optical fiber cord includes a silicone resin layer 12, an inner soft resin layer 13, a covering tension member layer 14, and an outer covering soft resin layer 15 on the outer periphery of an optical fiber wire 11 consisting of a core and a cladding.
are sequentially provided, and the covering tension member layer 14
is constructed by vertically attaching or twisting a plurality of string-like materials 14c, which are made by coating the outer periphery of high tensile strength fibers 14a with silicone resin 14b, around the inner soft resin layer.

The optical fiber cord with this structure uses heat-resistant and cold-resistant fluorine resin for the outer jacket and inner resin layer, and the tension member layer is also a string-like material made of high tensile strength fibers coated with silicone resin. This provides the advantage that it can be used in both high and low temperature ranges.

However, as a result of further research on the optical fiber cord, the present inventors discovered that the silicone resin 14 coated on the outer periphery of the string-like material 14c constituting the tension member layer 14 during the manufacture of the optical fiber cord.
b is a soft resin layer 1 that adheres to the soft resin layers 13 and 15 of the inner and outer coverings and has a relatively large coefficient of linear expansion;
3 and 15 are restrained by the tension member when expanding and contracting due to changes in the operating environment temperature, resulting in concentration of stress on the optical fiber strands, bending of the optical fiber cord, and increased transmission loss. I found out.

The present invention is based on this new knowledge.

Purpose of the invention The purpose of the invention is to prevent transmission loss from increasing in low and high temperature ranges, without deteriorating mechanical properties such as bending resistance and impact resistance, and which can be used over a wide temperature range from low to high temperatures. An object of the present invention is to provide an optical fiber cord that can be used in various applications.

Means for Solving the Problems The above objects are achieved by the optical fiber cord according to the present invention. In summary, the present invention provides a silicone resin layer, an internal flexural resin layer, a covering tension member layer, and an outer covering flexural resin layer in this order around the outer periphery of an optical fiber consisting of a core and a cladding. A plurality of string-like materials made by coating the outer periphery of high tensile strength fibers with silicone resin are arranged around the inner soft resin layer by vertically attaching or twisting them, and the void portion of the coated tension member layer is provided. This is an optical fiber cord characterized by being filled with talc.

Embodiments Next, the optical fiber cord according to the present invention will be explained in more detail with reference to the drawings.

Referring to FIG. 1, the optical fiber cord according to the present invention includes a silicone resin layer 22, an internal ductile resin layer 23, a covering tension member layer 2
4. An outer covering soft resin layer 25 is sequentially provided.

According to the present invention, the covering tension member layer has a structure similar to that described in connection with FIG. Silicone resin 24 is applied to the outer periphery of the high tensile strength fiber 24a, such as
A plurality of string-like materials 24c coated with B are arranged vertically or twisted together, and gaps in the coated tension member layer are filled with talc (talc) 24d. By filling the voids in the covering tension member layer with talc (talc) 24d, the silicone resin 24b coated on the outer periphery of the string material 14c during the manufacture of the optical fiber cord is transferred to the inner and outer soft resin layers. 23, 25 is completely prevented from sticking. Therefore, even if the soft resin layers 23 and 25, which have relatively large coefficients of linear expansion, expand and contract due to changes in the operating environment temperature, they are not restrained by the tension member layer 24 and can freely expand and contract. It does not cause stress to be concentrated on the optical fiber wire or cause the optical fiber cord to curve, thereby increasing transmission loss.

According to another aspect of the invention, as illustrated in FIG. It can be formed by extrusion coating the outer periphery of the resin tape layer 25b with a soft resin layer 25a. The soft resin tape layer 25b is used to prevent thermal deterioration of the internal layer structure at the extrusion temperature during extrusion coating of the soft resin layer 25a of the outer cover, and is also a talc-filled covering tape layer. This has the function of preventing talc from peeling off from the sion member layer 24.

Further, according to a preferred embodiment, the internal fluorine resin layer 23 includes a fluorine resin 23a extruded and coated around the outer periphery of the silicone resin layer 22, and a fluorine resin tape layer 2 wound around the fluorine resin layer 23a.
3b, and more preferably, a talc layer 23c is provided between the soft resin layer 23a and the soft resin tape layer 23b. By forming the internal soft resin layer 23 into a multilayer structure in this manner, the influence of heat on the optical fiber strand 21 can be significantly reduced. Furthermore, the talc layer 23c allows the layers to expand and contract more freely, and the influence of the expansion and contraction of each layer on the optical fiber wire 21 can be significantly reduced.

In the above configuration, the soft resin used for the inner and outer soft resin layers 23 and 25 is as follows:
ETFE (ethylene/tetrafluoroethylene copolymer; extrusion temperature 240°C to 330°C), PFA (tetrafluoroethylene/fluoroalkyl vinyl ether copolymer; extrusion temperature 290°C to 380°C), FEP
(Tetrafluoroethylene/hexafluoropropylene copolymer; extrusion temperature 270°C to 360°C) etc. are preferable. In addition, the outer covering's soft resin layer 25
By using a soft resin having a lower extrusion temperature than the inner soft resin layer 23, the extent to which the optical fiber strand 21 and the silicone resin layer 22 are adversely affected when covering the outer soft resin layer 25 is reduced.
Furthermore, tapes made of the above-mentioned fluorocarbon resins can be used as the fluorocarbon resin tape layers 23b and 25b, and the winding thickness thereof is usually 100 μm.

Example 1 An optical fiber cord was manufactured according to the configuration shown in FIG. In one embodiment of the present invention, the optical fiber wire 21 is made of quartz glass and has a diameter of 50 μm.
The outer periphery of the optical fiber 11 was coated with a silicone resin layer 22 to have an outer diameter of 0.4 mm.

The outer circumference of this silicone resin layer 22 has an outer diameter.
The inner soft resin layer 23a was extruded and coated to a thickness of 0.7 mm, and the talc layer 23c and the soft resin tape layer 23b were not provided in this example.
The fluorine resin is PFA (tetrafluoroethylene/fluoroalkyl vinyl ether copolymer;
An extrusion temperature of 290°C to 380°C was used. Next, a layer with an outer diameter of 2.3 mm is placed on the outside of the inner soft resin layer 23a.
The covering tension member layer 24 was formed so as to have the following properties. In the coated tension member layer 24, the tension member, that is, the string-like material 24c is formed into a string-like shape with an outer diameter of about 0.65 mm by coating the outer periphery of the Kevlar 24a with a silicone resin 24b.
4c was arranged by twisting 16 pieces. Furthermore, the voids in the tension member layer 24 were filled with talc.

Next, the outermost soft resin layer 2 is applied to the outermost layer of the covering tension member layer 24 so as to have an outer diameter of 3.0 mm.
5 was loosely extrusion coated. As the resin layer 25, ETFE (ethylene/tetrafluoroethylene copolymer; extrusion temperature: 240°C to 330°C) was used. Further, in this embodiment, the soft resin tape layer 25b
was not established.

Optical fiber cord with the above configuration is heated to −10°C to 80°C.
As a result of various tests carried out in a temperature range of

Effects of the invention The optical fiber cord according to the invention configured as described above has no increase in transmission loss in the low temperature range or high temperature range, and no deterioration in mechanical properties such as bending resistance and impact resistance. It has the advantage of being able to be used over a wide temperature range from low to high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of an optical fiber cord according to the present invention. FIG. 2 is a cross-sectional view of a conventional optical fiber cord. FIG. 3 is a cross-sectional view of the optical fiber cord improved in the present invention. FIG. 4 is an example of a tension member used in the optical fiber cord of FIG. 3. 21... Optical fiber wire, 22... Silicone resin layer, 23... Internal soft resin layer, 24... Covering tension member layer, 24d... Talc, 25
...Full resin layer on the outer cover.

Claims (1)

[Claims for Utility Model Registration] 1. A silicone resin layer, an inner fused resin layer, a covering tension member layer, and an outer covering fused resin layer are sequentially provided on the outer periphery of an optical fiber consisting of a core and a cladding, and The tension member layer is formed by disposing a plurality of string-like materials made of high tensile strength fibers coated with silicone resin on the outer periphery thereof, longitudinally attached or twisted together, around the inner soft resin layer, and the coated tension member layer An optical fiber cord characterized in that the voids are filled with talc. 2. The outer covering musculoskeletal resin layer consists of a fascia resin layer wound around the outer periphery of the covering tension member layer, and a flexure resin layer extruded and coated around the outer periphery of the fascia resin tape layer. The optical fiber cord according to item 1. 3. The inner soft resin layer comprises a soft resin layer extruded around the silicone resin layer and a soft resin tape layer wound around the soft resin layer. fiber optic cord. 4. Claim No. 4, wherein a talc layer is disposed between a soft resin layer extruded and coated around the outer periphery of the silicone resin layer and a soft resin tape layer wound around the soft resin layer. The optical fiber cord described in Section 3.