JPS6215510A - Running water preventing optical fiber cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a running-proof optical fiber cable using a water-absorbing and swelling substance.

(Prior art and its problems) Conventionally, in metal thread communication cables, K inside the cable
In order to prevent the running of water, it is common practice to include a water-absorbing and swelling substance that swells and gels when it absorbs water in the press-wrapping tape or fills it in the core wire. In recent years, similar measures have been taken for optical fiber cables, for example,
No. 207007 discloses a method in which an optical fiber and an intervening string are arranged around the outer periphery of a tensile member, and the outside of the optical fiber is covered with a pressing tape and a V-strip. Complementary products have been disclosed in which a water-absorbing and swelling substance is contained. In such optical fiber cables, the water-absorbing and swelling material absorbs water that has entered through cracks in the sheath, swells and turns into a gel, sealing the voids within the cable, effectively preventing water running. .

However, when an optical fiber cable containing a water-absorbing and swelling substance is used in a cold region, when the temperature drops below freezing, the gel water retained in the water-absorbing and swelling substance freezes and expands in volume, causing lateral pressure on the optical fiber cable. This has the disadvantage of causing transmission loss due to the addition of microbending.

(Objective of the Invention) The present invention has been made to eliminate the drawbacks of the above-mentioned prior art, and prevents transmission loss due to microbending of optical fibers by preventing gel water from hydrating even when used in cold regions. To provide a running-proof optical fiber cable capable of preventing running of water that has entered into the cable without causing any problems.

(Structure and operation of the invention) The present invention is a running-preventing optical fiber cable characterized by incorporating a water-running preventing material containing a water-absorbing and swelling substance and a freezing point depressant.

That is, since the anti-running optical fiber cable of the present invention uses the above-mentioned anti-running material, water that has entered the cable is absorbed by the water-absorbing and swelling substance and retained as gel water, and at the same time, the freezing point depressant is Because it dissolves, the gel water does not freeze and expand in volume, so no microbending occurs in the optical fiber.

Hereinafter, the present invention will be explained along with the drawings.

FIG. 1 shows an example of the anti-running optical fiber cable of the present invention, taking a unit type optical fiber cable as an example. This cable has a buffer layer (2
) and made of nine steel wires, etc.
Multiple optical fiber units (3) are attached to the outer periphery of 1).
is placed and the outside is pressed down and wrapped with tape (4j).

Laminated tape (5) made of aluminum tape, etc.
, a sheath (6) made of polyethylene or the like. The optical fiber unit (3) has a Tenseen member [powerful] in the center.
A plurality of optical fibers (8) and intervening strings (QO) having a coating layer (9) of silicone rubber, polyamide resin, etc. are arranged on the outer periphery, and the outer side of the optical fibers (8) is secured with a cushioning material (01) of non-woven fabric or woven fabric. It is covered with a rolled tape circle.

In this example, the pressure winding tape (41 (II) and the intervening string 0I are water running prevention materials and contain the water-absorbing swelling substance 01 and the freezing point lowering action, but the pressure winding tape f
4] (13) and all of the intervening matm do not need to be anti-water running materials, and as long as any one of them is a water-running preventing material, the object of the present invention can be achieved. If it is a water-preventing material, do not use the intervening string,
An optical fiber may be placed at the position of the intervening string.

The water-absorbing and swelling material QIK used in the present invention is cross-linked polyacrylate, starch acrylic acid lat polymer, starch/acrylonitrile graph) polymer, soybean acrylate copolymer, isobutylene/maleic anhydride copolymer, etc. Polymer, PVA/maleic anhydride copolymer.

So-called super absorbent polymers having a water absorption capacity of 50 to 1.000 times, such as CMC crosslinked products, are suitable.

Further, the shape of the water-absorbing and swelling substance may be any shape such as powder, powder, fibrous, film, or non-woven fabric.

The freezing point depressant 04) used in the present invention exists stably when the optical fiber cable is in normal use,
It is necessary that when water enters the cable, it dissolves and exhibits a freezing point lowering effect. Such freezing point depressants include N a CJ ) M j' Cj
So-called powdered alcohol is made by holding inorganic electrolytes such as ', polymer electrolytes such as sodium polyacrylate, and lower alcohols in dextrin powder.

These include antifreeze glycoproteins and surfactant proteins. Among these, surfactant proteins are particularly preferred since they exhibit a large freezing point lowering effect even in small amounts. The reason why a small amount of surfactant protein exhibits a large freezing point-depressing effect is thought to be because the freezing-point-depressing effect of surfactant protein is caused by supercooling of water, unlike the freezing point-depressing effect that is proportional to solute molar concentration. It will be done. This is presumed to be because surfactant proteins have the effect of inactivating ice crystal nuclei, and water does not start to turn into ice even if the temperature drops below freezing.

For example, surfactant proteins do not freeze even at this temperature. Note that the surfactant protein here refers to a hydrophilic protein to which a hydrophobic amino acid ester is added in the form of a peptide bond using the so-called enzyme modification method, in which a functional group is imparted to the protein using an enzyme as a lytic medium. ,
A reaction product using sukuVylated α1-casein as a woody protein and leucine n-dodecyl ester as an amino acid ester, and a nine-reaction product using gelatin as a hydrophilic protein and leucine n-dodecyl ester as an amino acid ester ( (hereinafter referred to as "surfactant gelatin").

Figure 2 shows an example of the presser-wound tape (41, Q3), which has a granular or powdery form inside the base material such as pulp fiber.

It contains a fibrous water-absorbing and swelling substance 03 and a freezing point depressing agent I. In order to increase the bonding strength of the tape, it may be heated and pressurized with water added thereto, or heated and pressurized with the addition of thermoplastic powder such as polyethylene. Examples of other pressure-wrapping tapes (41, (12)) include nonwoven fabric-like water-absorbing and swelling substances (for example, long-fiber cellulose nonwoven fabrics with carboxylmethylated cellulose), K-holding freezing point depressants; A film-like water-absorbing and swelling material containing a snoring and solid point depressant;
Alternatively, a fibrous water-absorbing and swelling material (for example, a polyacrylate copolymer moderately crosslinked on the surface of acrylic fibers) is made into a sheet such as a nonwoven fabric.
Some of these contain freezing point depressants. In particular, when the tape strength is set to 8, the above-mentioned pressing tape (41, 03 is tissue, non-woven fabric, woven fabric).

A reinforcing material 61 such as a mesh may be laminated, and FIG. 3 shows an example in which the reinforcing material is laminated on the presser-wound tape shown in FIG. 2.

An example of manufacturing the presser tape used in the present invention is shown below. First, pulp 3517d, cross-linked polyacrylic acid soda 14.51/d, and surfactant gelatin 0.5 N/♂ were placed on tissue 171/♂ using the 1 air lay method.
, a mixture of polyethylene powder 3117d is assembled and then heated and pressed to form a first-order long-fiber polyester non-woven fabric 4011/
Laminate d on the opposite side to the tissue side to obtain a pressing tape. This tape holds 1,000 cc of water per 1-, and thermostatic ovens f-5'C, -7@C, -10'C (
D When cooled to various temperatures, the water did not freeze at any temperature. On the other hand, when the same tape was formed and a similar experiment was performed, except without the addition of surfactant gelatin, water froze at both temperatures.

Other intervening strings a1 of the above-mentioned presser winding tie j may also be used as the water running prevention material. This intervening string (1) includes a string-like material made by twisting the above-mentioned presser-wound tape with slits, and a material with a water-absorbing and swelling material.
ν11-point desiccant and other fibers and resins are molded into a string shape.

In addition, according to 2 of the present invention, the running waterproof 1F-8 is limited to 1 to 1 or more pressure-wrapping tapes and intervening strings, and contains moisturizing substances and freezing point depressants.
: The voids within the cable may be filled with a water-absorbing and swelling substance and a freezing point depressant.

In the waterproof 1L type optical fiber cable of the present invention, when a tear or the like occurs in the sheath (61) for some reason and water from the outside enters, the water running prevention material 1 (containing water-absorbing and swelling substance 01 The substance quickly absorbs water and completely prevents swelling and gelation 1 to water running.This water absorption means that the freezing point depressant (14) dissolves in water at the time of t1, so the gel retained by the water-absorbing and swelling substance (131) The freezing point depressant is dissolved in water, so even if the freezing point reaches F, the gel water will hydrate and the volume will swell. When optical fiber cables are used in cold areas, etc., even if the 11□Li5 content is low after water absorption, the gel water retained in the water-absorbing and swelling material does not hydrate, and microbending occurs in the fibers. There is no need to worry about transmission loss occurring.

Although the explanation has been given using a unit type optical fiber cable as an example, the present invention is not limited to this, and may be applied to other types such as a spacer type optical fiber cable, a twisted type optical fiber cable, an optical fiber cord, and a twisted type optical fiber cable. Naturally, fiber optic cables are also included.

(Effects of the Invention) As described above, since the anti-running optical fiber cable of the present invention contains an anti-running material containing a water-absorbing swelling substance and a freezing point depressant, water that enters through cracks in the sheath, etc.
Water is quickly absorbed by the water-absorbing and swelling substance, and the water-absorbing and swelling substance swells into a gel, thereby preventing water running. Since a freezing point depressant is dissolved in the gel water that has been absorbed and retained by the water-absorbing and swelling material, it will not freeze and expand in volume even if the temperature drops below freezing after absorbing water. Therefore, the anti-running optical fiber cable of the present invention can effectively prevent running water, and even when used in cold regions, it can prevent various problems such as micro-bending of optical fibers due to freezing of intruding water. It can be used without causing any problems, so it can be used for four purposes.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of the optical fiber cable of the present invention. Fig. 2 is a sectional view of an example of the presser winding device used in the present invention. Fig. 3 is an example of the presser winding tape pond used in the present invention. Cross-sectional view of 1...Tension member 3...Optical fiber unit 4...Pressure winding tape 5...Template l-tag 6...Sheath 7...Tension member 8
... Optical fiber 10 ... Intervening string 12 ... Pressure winding tape 13 ... Water-absorbing swelling substance 14 ... Freezing point depressant 15 ... 1 is body 16 ... Reinforcement material

Claims (1)

[Scope of Claims] 1. An anti-water running optical fiber cable, characterized in that it contains an anti-water running material containing a water-absorbing and swelling substance and a freezing point depressant. 2. The water running prevention type optical fiber cable according to claim 1, wherein the water running preventing material is a pressure-wrapping tape. 3. The anti-water running optical fiber cable according to claim 1, wherein the anti-water running material is an intervening string. 4. The anti-running optical fiber cable according to claim 1, wherein the freezing point depressant is a surfactant protein.