JPH08171819A - Water-proofing material for layer twisted-type communication cable and layer twisted-type communication cable using it - Google Patents

Abstract

PURPOSE: To provide a water-proofing material (a water-proofing tape) which is utilized for a layer twisted-type communication cable, e.g. a copper metal type, an optical fiber loose tube type, etc., and which falls properly in gaps of communication wire bundles when coiled on the communication wire bundles, which are bundles produced by twisting a plurality of bundles of wires, to keep water proofing properties for a layer twisted-type communication cable. CONSTITUTION: A layer twisted-type communication cable is one having a two- layer structure consisting of a sheet substrate and a water absorptive composition layer on the substrate or one having a three-layer structure in which a cover cloth is put further on the water absorptive composition layer. The rigidity value in the vertical direction is within a range of 0.3-1.5gfcm<2> /cm and the rigidity value in the transverse direction is within a range of 0.2-0.5gfcm<2> /cm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a layer-twisted communication cable in which a bundle of a plurality of communication wires is bundled into a stranded wire and a sheath material is coated on the outer periphery thereof, and the inside of the sheath material of the communication cable. The present invention relates to a water-impervious material (water-impervious tape) used by being installed in Here, the “bundle of communication lines” refers to a bundle of copper wires for signal transmission, or an optical fiber core in which a plurality of optical fiber core wires are gathered in a loose tube.

[0002]

2. Description of the Related Art In recent years, most of the obstacles of communication cables, especially optical fiber cables, are caused by the intrusion of water into the cables, and the infiltration of water causes the strength of the optical fiber to deteriorate or the invaded water to freeze. As a result, pressure is applied to the optical fiber, which causes problems such as impairing optical transmission characteristics.

Therefore, a water-blocking material (water-blocking tape, water-blocking tape, or water-absorbing tape) having the characteristics of preventing water from entering the optical fiber cable and shortening the length of water entry even if water enters. Is generally referred to as a water-repellent tape, etc.), for example, as a one having a two-layer structure in which a water-absorbent composition layer is provided on a sheet base material, JP-A-1-207
Japanese Laid-Open Patent Publication No. 3-224729 and Japanese Laid-Open Patent Publication No. 3-224729 have a three-layer structure in which a cover cloth is further laminated on the water-absorbent composition layer. It is presented in Japanese Patent Laid-Open No. 4-357623.

By the way, conventionally, for example, JP-A-58-20
A layer-twisted communication cable as shown in Japanese Patent No. 7007 is known. As shown in the sectional structure of FIG. 9, the communication cable 50 has a plurality of optical fiber cores 56, 56, ... Outside the buffer layer 54 provided on the outer periphery of the linear tension member 52 having tensile strength. . Is provided, and a water blocking tape 60 is wound around the optical fiber cores 56, 56 ... With the water absorbing strings 58, 58 .. The polyethylene laminate tape 62 is wound, and the outermost layer is covered with a sheath material 64.

According to the layer-twisted communication cable disclosed in this publication, the water-absorbing cords 58, 5 are used when water enters the cable.
8 and the water-blocking tape 60 absorb water to form a gel, and the optical fiber cores 56, 56 in the sheath material 64.
..The space between them is sealed to prevent water from entering.

[0006]

However, the water-blocking material (water-blocking tape) used for such a communication cable generally has high rigidity. Therefore, when the water-blocking tape is wound around the cable, the optical fiber cores 56, 56 ...
The amount of water-blocking tape that falls into the gap between them is small, and the water-blocking performance cannot be fully exhibited.

The water-absorbing cords 58, 58 ... Are interposed between the optical fiber cores 56, 56 ... Due to the small amount of the water-blocking tape falling into the gap between the optical fiber cores. This is because the water absorption cord is interposed in the communication cable, and the number of communication lines per communication cable is restricted and reduced. Further, the outer diameter of the cross section of the communication cable becomes large, and the winding diameter in the winding operation at the time of manufacturing the cable also becomes large. Further, there is a problem that the manufacturing process is increased and the manufacturing cost is increased due to the use of the water absorbing string.

The present invention has been made to solve such a problem, and its purpose is to select the optimum range of the rigidity of the water blocking material (water blocking tape). It is intended to improve the water-blocking efficiency of the layer-twisted type communication cable. This eliminates the need for a water-absorbing string interposed between the optical fiber cores in the communication cable and economically provides the layer-twisted communication cable with excellent transmission efficiency to the market. Although this purpose has been described with reference to the above-mentioned problems for the optical fiber type communication cable for convenience of explanation, it is also applied to a so-called copper metal type copper wire cable.

[0009]

In order to achieve this object, the first water-blocking material for layer-twisted communication cables of the present invention comprises a water-absorbent composition layer formed on the surface of a sheet base material. However, the rigidity value of this water-impervious material is 0.3 in the vertical direction.
The gist is that it is in the range of up to 1.5 gfcm ² / cm and in the range of 0.2 to 0.5 gfcm ² / cm in the lateral direction.

A second water-impervious material for a layer-twisted type communication cable of the present invention has a water-absorbent composition layer formed on the surface of a sheet substrate, and a cover cloth is laminated on the water-absorbent composition layer. a made of Te, the rigidity value as the water barrier material is located in the longitudinal direction in the range of 0.3 ~1.5 gfcm ² / cm, and at a transverse 0.2 ~ 0.5gfcm ² / cm The gist is to be in the range.

As described above, the “water impervious material for cables” of the present invention
Include a two-layer structure in which a water-absorbent composition layer is provided on a sheet substrate, a water-absorbent composition layer provided on a sheet substrate, and a cover cloth on the water-absorbent composition layer. Included are laminated three-layer structures. Examples of the sheet base material include polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, polyacrylic fibers, non-woven fabrics such as rayon and vinylon, woven fabrics and knitted fabrics. It may be a combination of two or more kinds of synthetic fibers.

Further, the water-absorbent composition layer contains additives such as water-absorbent polymer particles, an organic binder, other surfactants, oxidative deterioration inhibitors, and inorganic fillers. Here, as the water-absorbent polymer particles, a polyacrylate cross-linked product,
Examples thereof include neutralized starch-acrylic acid graft polymer, crosslinked polyvinyl alcohol modified product, crosslinked isobutylene-maleic anhydride copolymer, polyethylene oxide crosslinked product, acrylamide-acrylic acid crosslinked polymer and the like.

The water-absorbent polymer particles have to fall apart when coming into contact with water and fall off from the sheet base material, but the particle shape and particle diameter are not particularly limited, and the particle shape is a perfect circle shape. It may be a thing or a distorted shape. Also, the particle size is such that the water absorption and swelling speed does not slow down and the falling off from the sheet substrate is not delayed (45
To 425 μm) is preferable, and to some extent (5% by weight or more) those having a particle size of 45 μm or less are also included in order not to impair the water impermeability of minute gaps such as gaps between cores of optical fiber cables or copper wire cables. It is desirable that These water-absorbent polymer particles may be used alone or in combination of two or more kinds.

As the organic binder, there are mainly rubber-based materials and thermoplastic elastomer synthetic resin-based materials. Examples of rubber materials include styrene-butadiene rubber, butyl rubber, butadiene rubber, isoprene rubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber, silicone rubber, chloroprene rubber, polyurethane rubber, acrylic rubber, chlorinated butyl rubber, epichlorohydrin rubber and others. To be

As the thermoplastic elastomer synthetic resin material, ethylene-vinyl acetate copolymer, ethylene-
Examples thereof include propylene copolymers, acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, polyester resins, polyamide resins, urethane resins, and other thermoplastic elastomers. This organic binder may be used alone or in combination of two or more kinds of these rubber materials and synthetic resin materials, or may be a mixture of randomly polymerized materials.

In the case of a water-impervious material having a three-layer structure, a non-woven fabric, a woven fabric, a knitted fabric or the like is used as the material of the cover cloth attached on the water-absorbent composition layer. This cover cloth is
The water-blocking tape is left in a high humidity environment such as the rainy season,
This is to prevent the tapes from blocking each other when they absorb a lot of moisture, and to prevent troubles such as soiling the guide rolls etc. while winding the fiber cable. Yes, and must withstand the tension of the laminating process.

Therefore, as the material of the cover cloth, the non-woven fabric sheet made of synthetic fiber is the best, and polypropylene fiber, polyethylene fiber, polyethylene terephthalate (PET) fiber, nylon, polyester fiber, polyacrylic fiber, etc. are used in terms of material. It can be manufactured by the spunbond method or the melt blow method.

In the third aspect of the present invention, a plurality of communication wire bundles each having a plurality of communication wires are bundled into a bundled stranded wire, a water impervious tape is wrapped around the outer circumference, and a sheath material is coated on the outer circumference. In the layer-twisted communication cable, the water-impervious tape has a water-absorbent composition layer on the surface of a sheet substrate, and the water-impervious tape itself has a rigidity value of 0.3 in the longitudinal direction.
˜1.5 gfcm ² / cm and laterally in the range 0.2 to 0.5 gfcm ² / cm.

Further, in the fourth aspect of the present invention, a plurality of communication wire bundles in which a plurality of communication wires are bundled are further bundled into a stranded wire shape, a water impervious tape is wound around the outer circumference, and a sheath material is coated on the outer circumference. A layer-twisted communication cable having the following structure, wherein the water-permeable tape has a water-absorbent composition layer on a surface of a sheet base material, and a cover cloth is bonded onto the water-absorbent composition layer. The waterproof tape itself has a rigidity value within the range of 0.3 to 1.5 gfcm ² / cm in the longitudinal direction and within the range of 0.2 to 0.5 gfcm ² / cm in the lateral direction. Is presented. These layer-twisted communication cables are applicable to both the one in which the communication wire is a copper wire and the one in which the communication wire is an optical fiber.

Thus, according to the present invention, whether the waterproof property of the cable (water impervious tape) for the cable has a two-layer structure or a three-layer structure, the longitudinal direction (tape length direction) ) In the range of 0.3 to 1.5 gfcm ² / cm, and in the lateral direction (tape width direction) of 0.2 to 0.0.
It is required to be in the range of 5 gfcm ² / cm. For that purpose, it is desired that the total thickness of the water-blocking material is in the range of 0.25 to 0.65 mm.

When the water-impervious material does not satisfy the requirements of the rigidity in the longitudinal direction or the rigidity in the lateral direction, for example, the rigidity value in the longitudinal direction is higher than 1.5 gfcm ² / cm or in the lateral direction. If the rigidity value of the cable is higher than 0.5 gfcm ² / cm, the water-blocking material (water-blocking tape) will fall into the gap between the communication wire bundles too little, resulting in water-blocking performance when water enters the cable. Results inferior to.

On the other hand, the rigidity value in the longitudinal direction is 0.3 gfcm ² /
lower than 0.1 cm, or lateral stiffness is 0.2 gf
When it is lower than cm ² / cm, the water-impervious tape falls into the gap between the communication wire bundles well, but not only the sheet base material is thinned to satisfy the rigidity value, but also the water-absorbent composition on the sheet base material. It is not preferable because the adhered amount of water will not be reduced, resulting in a problem that the water impermeability is deteriorated.

Various conditions can be set in order to optimize the rigidity characteristic. For example, when the sheet base material is a non-woven fabric, the unit weight of the non-woven fabric is controlled,
When attaching the cover cloth, use a thin one so that the total thickness of the water-blocking tape is 0.25.
It is effective to keep the thickness within the range of to 0.65 mm.

In the water-blocking material of the present invention, the rigidity value is improved by adding an inorganic filler such as silica to the water-absorbent composition. Also, it is effective to bond a cover cloth on the water-absorbent composition layer or a reinforcing film on the sheet base material to increase the rigidity value, but simply by bonding the cover cloth etc., the rigidity value is satisfied. Not necessarily
The basis weight of the sheet base material, the content of the water absorbing composition, the material of the cover cloth, the basis weight of the cover cloth and the like contribute synergistically.

Further, although not directly related to the present invention, a proper amount of a surfactant is added to improve the hydrophilicity of the organic binder, or the organic binder is prevented from being deteriorated by heat to be discolored or cured. Therefore, it is recommended to add an antioxidant. Examples of the surfactant include anionic surfactant, nonionic surfactant, cationic surfactant,
Examples thereof include carboxylic acid metal salts, polyhydric alcohols, amino alcohols, linear polyethers, sugars, sugar alcohols, sorbitan fatty acid esters, glycidyl ethers of polyhydric alcohols, alkyl phosphate alkali metal salts, polyoxyethylene alkyl ethers and the like. Further, when an inorganic filler such as silica is blended in order to increase the rigidity value, the tackiness (stickiness) at the time of winding the optical fiber cable is also improved.

[0026]

EXAMPLES Examples of the present invention will be described in detail below. First, a schematic configuration of a layer-twisted communication cable to which the present invention is applied is shown in FIGS. 1 to 4 and described. 1 and 2 show an example of a metal-type layer-twisted communication cable using a copper wire as a communication wire. In this metal type communication cable 10, a large number of copper wires 12, 12, ... Are bundled together, and the copper wire bundles 14, 14, ... 14 ... A water-impervious tape 16 is wrapped around the outer periphery of the group, and a sheath material 18 is further coated on the outer periphery thereof.

On the other hand, FIGS. 3 and 4 show an example of an optical loose tube type layer twist type communication cable using an optical fiber line as a communication line. This optical loose tube type communication cable 20 includes a plurality of optical fiber lines 22,
22 ... through a single loose tube 24, which is bundled outside the buffer layer 27 provided around the tension member 26 in a twisted line, and the optical loose tube bundles 24, 24
... The water shielding tape 16 is wrapped around the outer circumference of the group, and the outer circumference thereof is covered with the sheath material 28. Next, Table 1 shows the types of various test samples of the product of the present invention and the comparative product,
The test results are shown together.

[0028]

[Table 1]

Specimen samples 1 to 3 represent a water-impervious material (impermeable tape) having a two-layer structure in which a water-absorbent composition layer is provided on a sheet base material, and Specimen samples 4 to 10 are sheet base materials. This shows a water-impervious material (water-impervious tape) having a three-layer structure in which a water-absorbent composition layer is provided on the material and a cover cloth is further coated on the water-absorbent composition layer. Among the two-layer structure of the test samples 1 to 3, the test sample 1 is a comparative product, and the test samples 2 and 3 are the products of the present invention.
Further, among the three-layer structure of the test samples 4 to 10, the test samples 4 to 6 are comparative products, and the test samples 7 to 10 are the products of the present invention.

Thus, the sheet base material of the water-impervious material of each of the test samples 1 to 10 is a polyester spunbonded non-woven fabric (trade name “Marix 70 ××× WT manufactured by Unitika Ltd.”).
O ”), a polyester single yarn having a fineness of 2 denier is used. As shown in Table 1, the test samples 1 to 3 (two-layer structure) have a basis weight of 40 g / m 2.
^A constant value of ² is adopted, and the number of steps of the test samples 4 to 10 (three-layer structure) is selected in the range of 20 to 60 g / m ² . On the other hand, as the water-absorbent composition, three types of composition blends shown in Table 2 below were tested. In the following description, all units "parts" mean "parts by weight".

[0031]

[Table 2]

The water-absorbent compositions No. 1 to No. 3 are all water-absorbent resin polymers which are crosslinked metal salts of isobutylene-maleic acid copolymer (trade name "K" manufactured by Kuraray Co., Ltd.
I gel 201K-F3 ") 200 parts, to styrene-butadiene-styrene (SBS) thermoplastic elastomer (trade name" Califlex TR-11 "manufactured by Shell Chemical Co., Ltd.
01 ”) and butyl rubber (trade name“ Essobutyl # 268 ”manufactured by Esso Co., Ltd.) are mixed in a ratio of 100 parts to form a basic composition.

In this case, the compounding ratio of SBS thermoplastic elastomer and butyl rubber (IIR) was 80 in No. 1.
Part: 20 parts, No. 2 20 parts: 80 parts, No. 3 0
Copies: 100 copies. Then, 4 parts of a polyethylene glycol (Nippon Yushi Co., Ltd. trade name "PEG600") surfactant and an phenolic oxidative deterioration inhibitor (Ciba Geigy trade name "Irganox 565") were added to these compositions as additives. 1 part each is compounded.

Table 1 shows which type of water-absorbent composition was used for each of the test samples 1 to 10, and the amount of the water-absorbent composition attached is also shown in Table 1. Is shown in. The amount of the water-absorbing composition deposited on the two-layer structure (test samples 1 to 3) was fixed at 150 g / m ^{2 and} was 3
The layered structure (test samples 4 to 10) has a small 110 g / m ² only for the test sample 4 and 15 for the other test samples 5 to 10.
It was kept constant at 0 g / m ² . As a result, the tape thickness of the two-layer structure (test samples 1 to 3) was all constant at 0.3 mm.

Next, a description will be given of the cover cloth material of Test Samples 4 to 10 having a three-layer structure in which the cover cloth is laminated on the water absorbing composition layer.
No. 0 is a spunbonded nonwoven fabric made of polypropylene (trade name "Syntex PK-102" manufactured by Mitsui Chemicals & Petroleum Co., Ltd.), and a polypropylene single yarn having a fineness of 4 denier is stuck together, and the basis weight of the nonwoven fabric is 12 g / m ² . It is constant.

As a result, the tape thickness of the test sample 4 having the smallest amount of the water-absorbing composition attached was 0.2 mm, and the test sample 5 having the smallest weight of the non-woven fabric of the sheet base material. The tape was thin. It goes without saying that the tape thickness increases as the weight of the nonwoven fabric of the sheet substrate increases.

This water-blocking material is prepared by dissolving and dispersing an organic binder such as a binder resin in an organic solvent such as toluene, methyl ethyl ketone, and ethyl acetate by using a stirrer, and then mixing the water-absorbent polymer particles with this. Further, other additives are mixed as needed. Then, the surface of the sheet substrate is coated with this using a bar coater, a roll coater or the like to form a water absorbing composition layer.

Then, when laminating the cover cloth on the surface of the water-absorbent composition layer, a laminating method is used. At that time, the cover cloth is laid on the water-absorbent composition layer, and the upper and lower parts of the polyester film for release ( (75 μm thick), press the surface pressure of 5 kg / cm ² × 3 minutes with a press machine adjusted to a temperature of 150 ° C., and then cool the press temperature to 80 ° C. in a pressurized state. As a result, a water blocking tape with a cover cloth can be obtained.

Next, various test results will be described. As the test items, rigidity characteristics (longitudinal direction and lateral direction) as a water-impervious material, dipability into gaps, and water impermeability (T-type and L-type) were measured, and each was measured by the methods described below.

(1) Rigidity property In each of the test samples 1 to 10, a sample 30 having a length of 20 cm and a width of 1 cm or more is used as a fixed chuck 3 of an apparatus as shown in FIG.
It is sandwiched and fixed between 2 and the movable chuck 34 (arranged at 1 cm intervals). Then, the movable chuck is rotated in one direction within the range of curvature K = −2.5 to +2.5 (cm ⁻¹ ) around the fixed chuck and then further rotated in the opposite direction to bend and deform the sample. By giving the value, the flexural rigidity value per unit length (unit: gfcm ² / cm ² ) was measured (referred to as “KES method”). In order to measure the longitudinal rigidity value and the lateral rigidity value, a cutout sample in the tape length direction and a cutout sample in the tape width direction of the water blocking material (water blocking tape) are being tested.

(2) Drop-in evaluation test As shown in FIG. 6, 10 mmφ simulating a cable core
Three rods of × 500 mm are bundled, and a water-impervious sheet having a tape width of 20 mm is wrapped around the rod while applying a load of 2 kg. Then, the amount of drop of the water-blocking material sheet between the rods at the central portion in the length direction of the rods was measured with a caliper.

As a result, as shown in Table 1, the one having a low rigidity value (test sample 4) has a large amount of drop of the waterproof sheet between the rods, and the one having a high rigidity value (test sample). It was found that in Samples 1, 5, and 6), the amount of the impervious sheet falling between the rods was small.

(3) T-shaped water blocking test Next, the T-shaped water blocking test will be described. This is because some force is applied to the sheath material that is the outer jacket of the cable.
It is a test of how to prevent the intrusion of water in the longitudinal direction of the cable when a hole or a crack is formed in the sheath material and water intrudes from the hole. This device is shown in FIG.
In the following description, a 3 mmφ round bar 40 is bundled in a model of this type of layer-twisted type communication cable, which is wrapped with a water-blocking tape 16, and a sheath material is assumed on the outer side thereof to achieve heat shrinkability. Simulated cable 42 covering tube 41
Create

Further, the heat-shrinkable tube 41 in the middle of the simulated cable 42 is peeled off for 1 cm, and a water supply pipe 44 is provided on the heat-shrinkable tube 41.
4 is filled with artificial seawater to a height of 1 m, a cock (not shown) is opened to penetrate the water-impervious tape 16, and after 24 hours, how long the gap between the round bars of the simulated cable 42 is. The water running performance in the T-shape was evaluated depending on whether the water ran and was dammed. It is judged that the one with a short running length of water is excellent in water impermeability, and if it exceeds 50 cm, it cannot be used.

(4) L-Shaped Water Blocking On the other hand, the L-shaped water blocking will be explained. This is because when the cable is cut by an external force and water enters from the cross section of the cable, the water in the longitudinal direction of the cable is cut. It is a test of how to prevent the invasion of. This device will be described with reference to FIG. 8. First, a simulated cable 42 is prepared in the same manner as the T-shaped water shield test shown in FIG. 7, and a water supply pipe 46 is provided at one end thereof. Then, a cock (not shown) is opened in a state where the water supply pipe 46 is filled with artificial seawater to a height of 1 m to inject water into the cable 42, and after 24 hours, how long the seawater runs into the cable 42. The water running property in the L-shape was evaluated depending on whether or not it was dammed. The shorter the running length of water is, the better the L-shaped water shield is.
If it exceeds 8 m, it is determined that it cannot be used.

As a result, first, the test samples 1 having a two-layer structure were prepared.
Considering No. 3, it was judged that the comparative product (test sample 1) was defective (marked with X) in both T-shaped and L-shaped water-impervious properties, and both of the present invention products 2 and 3 were impervious. It was judged that the water characteristics were excellent (marked with ○). And for this reason,
Since the comparative product (test sample 1) has a high rigidity value, especially in the longitudinal direction, the amount of drop in the gap when the water-blocking tape is wrapped around a bundle of round bars is small (the drop is small).
Therefore, it is considered that when water entered the cable, it was easy to run and it was difficult to block the intrusion of water.

The reason why the rigidity values of the comparative product (test sample 1) and the invention product (test samples 2 and 3) are different is that the water-absorbing composition layer provided on the sheet substrate is used. And the compounding ratio of the styrene-butadiene-styrene thermoplastic elastomer of the organic binder contained in the composition was high.

Next, considering the test samples 4 to 10 having the three-layer structure, the comparative products (test samples 4 to 6) are defective (marked with an X) in both T-shaped and L-shaped water-blocking properties. Is the judgment of
All of the products 7 to 10 of the present invention have excellent water impermeability (marked with ○)
It was a decision. For this reason, first of all, the test sample 4 among the comparative products may have a large amount of drop into the gap when the water-blocking tape is wrapped around the bundle of round bars. It is considered that the water-blocking property was impaired because the amount of the water-absorbent composition deposited was too small.

Further, in Comparative Samples 5 and 6, the compounding ratio of the styrene-butadiene-styrene thermoplastic elastomer of the organic binder contained in the composition of the water absorbing composition layer provided on the sheet substrate was high. It is considered that the amount of water-blocking tape falling into the gap between the rods was reduced, which made it difficult to block water from entering the cable.

On the other hand, the product of the present invention (test samples 7 to 1)
The results that 0) were excellent in water-impervious properties were obtained because the rigidity value was in the appropriate range and the composition content and the amount of the water-absorbing composition were appropriate. Seem. Judging from this result, the rigidity value is 0.3 to 1.5 gfcm in the longitudinal direction (tape length direction).
It is in the range of ² / cm and in the lateral direction (tape width direction) in the range of 0.2 to 0.5 gfcm ² / cm,
It can be said that it is possible to maintain a considerable amount of the waterproof tape falling into the gap between the communication wire bundles, which is preferable. It is desirable that the amount of the water-blocking tape that falls into the gap between the communication wire bundles be 0.2 mm or more.

As described above, the type (composition content) and the coating amount (adhesion amount) of the water-absorbing composition applied on the sheet base material are effective in improving the water-blocking performance. If the total thickness of the water tape is 0.25 mm or more, there is a synergistic effect with the amount of depression, but it is presumed that good results can be obtained for the water-blocking property. still,
The upper limit of the tape thickness is 0.65 mm, and if it is more than that, the weight of the non-woven fabric of the sheet base material is increased and the water absorbing composition layer is thickened. Improvements can no longer be expected and should be avoided as the economic cost of increasing product costs is greater.

Others In the present invention, various examples (test samples)
However, the present invention is not limited to the above examples, and various improvements and modifications can be made without departing from the spirit of the present invention. For example, it is necessary to change various sheet base materials, water absorbing compositions, cover cloths, etc., or change the blending amount of the water absorbing compositions, the fineness of the sheet base materials, the cover cloths, etc. The directional and lateral rigidity values falling within the numerical range of the present invention are in accordance with the gist of the present invention.

[0053]

As described in the above embodiments, the cable water-impervious material (water-impervious tape) of the present invention can be adjusted by setting the longitudinal rigidity value and the lateral rigidity value within appropriate ranges. When used as a winding tape for a layer-twisted type communication cable, the water-impervious tape can be easily dropped into the gap between communication bundles, thereby maintaining the water-impervious performance of the water-impervious tape. Therefore, it is possible to provide the layer-twisted communication cable with high transmission efficiency to the market without the need for interposing a water-absorbing string in the communication cable as in the conventional case.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a copper metal type as an example of a layer-twisted communication cable to which the present invention is applied.

FIG. 2 is a cross-sectional view of the copper-metal type layer-twisted communication cable shown in FIG.

FIG. 3 is an external perspective view showing an optical fiber loose tube type as another example of the layer-twisted communication cable to which the present invention is applied.

FIG. 4 is a sectional view of the optical fiber loose tube type layer-twisted communication cable shown in FIG.

FIG. 5 is a schematic diagram showing a main part of a rigidity value measurement test (KES method) device used for confirming the effect of the present invention.

FIG. 6 is a schematic configuration diagram of an apparatus for evaluating a falling amount of a water-blocking material sheet into a slot, which is also used for confirming the effect of the present invention.

FIG. 7 is a perspective view of a T-shaped water impermeability measuring device.

FIG. 8 is a perspective view of an L-shaped water impermeability measuring device.

FIG. 9 is a sectional view of an optical fiber type as an example of a conventionally known layer-twisted communication cable.

[Explanation of symbols]

 10 metal type layer-twisted type communication cable 12 copper wire 14 copper wire bundle 16 water blocking tape 18 sheath material 20 optical loose tube type layer-twisted type communication cable 22 optical fiber line 24 loose tube 28 sheath material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01B 11/00 Z 4232-5L

Claims (12)

[Claims] 1. A water-impervious material for a layer-twisted communication cable, comprising a water-absorbent composition layer formed on the surface of a sheet base material, wherein the water-impervious material has a rigidity value of 0.3 to 0.3 in the longitudinal direction. 1.5 gf
It is in the range of cm ² / cm and is 0.2 to 0.0 in the lateral direction.
Water-impermeable material for layer-twisted communication cables, which is in the range of 5 gfcm ² / cm. 2. The sheet base material is a polyester-based non-woven fabric, and has a total thickness as a water blocking material of 0.25 to
The water impervious material for layer-twisted communication cables according to claim 1, wherein the water impervious material is in the range of 0.65 mm. 3. A layer-twisted communication cable obtained by bundling a plurality of communication wire bundles each having a plurality of communication wires bundled into a stranded wire, wrapping a water-blocking tape around the outer circumference, and covering the outer circumference with a sheath material. The water-impervious tape has a water-absorbent composition layer on the surface of the sheet substrate, and the rigidity value of the water-impervious tape itself is in the range of 0.3 to 1.5 gfcm ² / cm in the longitudinal direction. And laterally 0.2 to 0.5 gfcm ² / c
A layer-twisted communication cable characterized by being in the range of m. 4. The sheet base material is a polyester-based non-woven fabric, and the entire thickness of the waterproof tape itself is 0.2.
The layer-twisted communication cable according to claim 3, wherein the layer-twisted communication cable is in the range of 5 to 0.65 mm. 5. The layer-twisted communication cable according to claim 3, wherein the communication wire is a copper wire. 6. The layer-twisted communication cable according to claim 3, wherein the communication line is an optical fiber. 7. A water-impervious material for layer-twisted communication cables, comprising a water-absorbent composition layer formed on the surface of a sheet base material, and a cover cloth laminated on the water-absorbent composition layer, Rigidity value as a water barrier is 0.3-1.5 gf in the vertical direction
It is in the range of cm ² / cm and is 0.2 to 0.0 in the lateral direction.
Water-impermeable material for layer-twisted communication cables, which is in the range of 5 gfcm ² / cm. 8. The sheet base material is a polyester-based non-woven fabric, and has a total thickness of 0.25 to 10 as a water-blocking material.
The water impervious material for a layer-twisted communication cable according to claim 7, which is in a range of 0.65 mm. 9. A layer-twisted communication cable obtained by bundling a plurality of communication wire bundles each having a plurality of communication wires bundled into a stranded wire, wrapping a water-blocking tape around the outer circumference, and covering the outer circumference with a sheath material. The water-impervious tape has a water-absorbent composition layer on the surface of a sheet base material, and a cover cloth is attached onto the water-absorbent composition layer, and the water-impervious tape itself. Has a stiffness value of 0.3 to 1.5 gf in the vertical direction.
It is in the range of cm ² / cm and is 0.2 to 0.5 in the lateral direction.
A layer-twisted communication cable characterized by being in a range of gfcm ² / cm. 10. The sheet base material is a polyester-based non-woven fabric, and the water-proof tape itself has a total thickness of 0.1.
The layer-twisted communication cable according to claim 9, which is in a range of 25 to 0.65 mm. 11. The layer-twisted communication cable according to claim 9, wherein the communication wire is a copper wire. 12. The water impervious material for a layer-twisted communication cable according to claim 9, wherein the communication line is an optical fiber.