JPH03145609A - Optical cable - Google Patents

Abstract

PURPOSE:To improve fire retardance and optical transmission characteristics by specifying the waterproof intimate mixture packed in contact with coated optical fibers. CONSTITUTION:The waterproof intimate mixture packed in to the gap of the optical cable in contact with >=1 pieces of the optical fibers or coated optical fibers consists of 75 to 97 wt.% oil and oil mixture expressed by formula I, 3 to 15 wt.% thickener and 0.001 to 0.1 wt.% platinum or platinum compd. In the formula I, R', R'', R''' are selected from any of an alkyl group, cycloalkyl group, slkenyl group, and aryl group. Hydrogen atoms are used for all of these groups which are bonded to the carbon atoms thereof. Halogen atoms do not generate toxic gases at the time of combustion and are, therefore, not substd.. Thus, the optical cable which is stable not only in fire retardance but in the transmission characteristics as well is obtd..

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an optical cable that uses glass fiber as an optical transmission path, and is particularly effective in terms of flame retardancy and waterproofness.
The transmission characteristics were also devised to be stable.

<Conventional Technology> If a communication cable spreads and is damaged by a fire, there is a risk of chaos in today's information-oriented society. In particular, many cable materials, including polyethylene, are easily flammable. Therefore, making the cable flame retardant was considered.

On the other hand, in conventional cables, in order to protect the optical fiber from moisture, the cable is filled with a waterproofing compound such as petrolatum-based sherry, mineral oil-based sherry, polybutene-based sherry, or a gel-like compound that is a mixture of thermoplastic nidistomer and process oil. are doing.

However, since the main component of these waterproof mixtures is flammable, they easily catch fire and burn. Therefore, a silicone-based shelly disclosed in Japanese Unexamined Patent Application Publication No. 63-235398 has been proposed, and a waterproof and flame-retardant optical fiber cable has been developed using this.

<Problems to be Solved by the Invention> However, even optical fiber cables using the above-mentioned flame-retardant and waterproof mixture still have problems that need to be improved.

That is, when an optical fiber cable is manufactured using the above-mentioned flame-retardant and waterproof mixture, although the flame-retardant properties are satisfactory, there are problems with the optical transmission properties.

Furthermore, in recent years, optical transmission using optical fibers has been carried out at longer wavelengths (1.55 μm band) with lower loss, but this wavelength band is extremely sensitive to external forces, especially bending. Another problem is that optical fiber cables using the above-mentioned flame-retardant and waterproof mixtures do not satisfy optical transmission characteristics.

In view of the above-mentioned circumstances, it is an object of the present invention to provide an optical cable that is not only flame retardant but also has improved optical transmission characteristics.

Means for Solving the Problems> The structure of the optical cable according to the present invention to achieve the above object is as follows: In the cavity of the optical cable, at least one or more bare optical fibers or cored optical fibers are contacted with a waterproof mixture. an optical cable filled with a material, wherein the waterproof mixture is: (1) 75 to 97% by weight of an oil represented by the following general formula fl) and a mixture thereof; [R”2S
in], -3iR"' -1) ■ 3 to 15% by weight of a thickening agent; ■ o, o o i ~ 01% by weight of gold or a platinum compound, and the consistency of the waterproofing mixture is such that 200 or more at -40℃, and the consistency change from +80℃ to -40℃ is 150
It is characterized by being within

Hereinafter, the configuration of the present invention will be explained in detail.

In the present invention, the waterproof mixture is a silicone oil component represented by the following general formula (1), a thickener component that imparts thixotropy to this silicone oil component, and platinum that imparts flame retardancy to a product consisting of these components. Moreover, the main component is a platinum compound, and in addition to the above, an antioxidant, an ultraviolet stabilizer, etc. may be added as appropriate.

The viscosity of the silicone oil represented by the above general formula (1) is preferably 100 centistokes or more and 10,000 centistokes or less. This is because if the viscosity is less than 100 centistokes, the viscosity and dropping point of the composition will be low, causing it to flow out from within the cable.
This is because if it exceeds 000 centistokes, the viscosity of the acid will increase, making it difficult to fill it into the cable.

Further, the content of the silicone oil in the composition is preferably 75 to 97% by weight based on the total amount of the composition. This is because if it exceeds 97% by weight, the oil will easily separate and the stability of the grease properties will deteriorate, and if it is less than 75% by weight, the viscosity of the composition will increase and it will be difficult to fill it into the cable. It is.

Examples of thickeners that impart thixotropy to the silicone include inorganic powders with a diameter of 1 μm or less, such as silica powder, talc clay, and carbon, whose content is 3% by weight based on the total amount of the composition. 15% by weight or more
The following are preferred. This is because if it is less than 3% by weight, it will be difficult to impart thixotropic properties to the silicone oil, and if it exceeds 15% by weight, it will become putty-like and cannot be used as a waterproof mixture.

Examples of the platinum or platinum compound for imparting flame retardancy to the composition include platinum metal and platinum compounds such as chloroplatinic acid. Note that the content of platinum or platinum compound is 0. It is desirable that OO be 1% by weight or more, and 0% by weight or more.
．． If it is less than 0.001% by weight, the flame retardant effect will be extremely poor.

The consistency of flame-retardant waterproof mixtures consisting of such components is
It is preferable that the consistency is 200 or more at -40°C, and the consistency change from +80°C to -40°C is 150 or less. This is because transmission loss increases if the consistency is less than 200° C. at -40° C., which is considered to be the lowest operating temperature range for optical cables. On the other hand”-80
The reason why the change in consistency from 150 degrees Celsius to -40 degrees Celsius is set within 150 is because if it is more than 150, the transmission characteristics of the optical fiber at long wavelengths will not be satisfied.

The consistency of the present invention at 40°C is 200 or more, and +
A waterproof mixture with a consistency change of 150 from 80° C. to -40° C. can be produced by selecting 0 for each of the silicone oil component and the thickener component and selecting their respective blending ratios.

Note that the consistency here is an index indicating the hardness of a waterproof compound specified by JISK-2220, and the smaller the value of the consistency, the harder it is.

In the present invention, the optical fiber refers to a glass fiber for optical transmission whose main component is silica glass. Optical fiber cores are quartz glass coated with a single layer of primary repeating or multiple layers of secondary repeating, or coated optical fibers arranged in parallel, and then coated with a single layer or multiple layers. Refers to something that has been repeated.

An example of an optical cable filled with the waterproof mixture according to the present invention is shown in FIG. As shown in the figure, optical cable 1
0 is a waterproof mixture 14 according to the present invention, in which a plurality of two integrated optical fiber elements 1s13 are arranged in each groove 12a of a slot 12 in which one tension member 11 is arranged in the center.
The fiber is filled with the fibers, pressed and rolled 15, and then covered with a jacket 16 to form a cable, resulting in a grouped spacer type optical cable.

In addition, the waterproof mixture according to the present invention can be used in various optical cables such as loose tube type optical cables and tape slot type optical cables.

In addition, when converting into a cable, the components of the cable, such as the outer sheath, slot, and spacer.

Setting the oxygen index of each constituent material of the tube to within 150 is particularly effective in terms of flame retardancy.

If an optical cable is manufactured using the waterproof mixture according to the present invention in the above configuration, the composition of the waterproof mixture can be expressed by the general formula (
A silicone oil shown in 1), a thickener that gives the silicone oil thixotropic properties, and platinum or a platinum compound that gives flame retardancy, and has a consistency of 200 or more at -40°C and a temperature range from -40°C to +80°C. Since the consistency change is 150 or less, it is possible to obtain an optical cable that is not only flame retardant but also has stable transmission characteristics.

Embodiment Example The present invention was carried out using an optical cable having the cable configuration shown in FIG.

As the optical fiber wire 13, the glass fiber diameter is 125μ
Using a single-mode fiber of 250 μm coated with ultraviolet curable resin and having an outer diameter of 250 μm,
Four units each of so-called two-core tape core wires, which are two fiber optic fibers 13 made of ultraviolet curable resin, are inserted into the six grooves of the SZ twisting slot 12 made of flame-retardant polyethylene (oxygen index 29). 12a together with a waterproof mixture having the composition shown in Table 1, and then press and roll 15.
After that, a shell made of flame-retardant polyethylene (oxygen index 27)
It was made into a cable.

For comparison, cables were made in the same manner using the compositions according to the conventional examples shown in Table 1.

The following tests were conducted using the obtained optical cable.

■ Vertical l-ray combustion test specified in T EEE 5 standard 383 ■ Measurement of optical fiber transmission loss change (130 μm band and 1.55 μm band) at -40°C and +80°C ■ Be1lcore 5 specification
The so-called drip test, which observes the dripping of a waterproofing mixture specified in TR-TSY-000020, JP-A-3-145609 (5) 4 From the results in Table 1, the flame retardance and transmission characteristics of the optical cables of Examples 1 and 2 were evaluated. It was confirmed that the results were satisfactory and that it was suitable for use as a waterproof mixture for optical cables.

<Effects of the Invention> As described above in detail along with the examples, the optical cable of the present invention has the advantage of being highly flame retardant and having stable transmission characteristics from low to high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical cable according to an embodiment of the present invention. In the drawing, 10 is an optical cable, 11 is a tension member, 12 is a thrower l-1, 12a is a groove, 13 is an optical fiber, 14 is a waterproof mixture, 15 is a presser winding, and 6 is an outer cover. Agent for patent applicant Sumitomo Electric Industries, Ltd.

Claims (1)

[Scope of Claims] 1) An optical cable in which a waterproofing mixture is filled in a cavity of the optical cable in contact with at least one bare optical fiber or cored optical fiber, the waterproofing mixture comprising: (1) 75 to 97% by weight of an oil represented by the following general formula (1) and a mixture thereof, and chemical formula; R'_3SiO-[R''_2SiO]_n-S
iR″′_3...(1) {R′, R″, R″′; halogen-unsubstituted alkyl group, cycloalkyl group, alkenyl group, or aryl group} (2) 3 to 15% by weight thickener and (3) 0.001 to 0.1% by weight of platinum or a platinum compound, and the consistency of the waterproofing mixture is 200 or more at -40°C, and the consistency from +80°C to -40°C. An optical cable characterized in that the change is within 150. 2) The optical cable according to claim 1, wherein the outer jacket material constituting the optical cable has an oxygen index of 27 or more. 3) Claim 3. The optical cable according to item 1 or 2, wherein the member housing the bare optical fiber or cored optical fiber of the optical cable has an oxygen index of 27 or more.