JP2814251B2 - Waterproof tape for cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a water stoppage for a cable which prevents water from penetrating in a longitudinal direction and an inward direction of a cable when water enters a communication cable or a power cable. It is about tape.

<Prior Art> Conventionally, it is known to use a water stop tape in order to prevent water running in a communication cable such as an optical fiber cable or a power cable from flowing into the cable.

For example, FIG. 2 is a cross-sectional view showing an example of the structure of a non-metal waterproof optical fiber cable for a trunk line. A water-stop tape 8 and a polyethylene are provided on a grooved polyethylene slot 7 having an FRP tensile wire 6 at the center. An outer jacket 9 is provided sequentially, and an optical fiber ribbon 10 is accommodated in a groove 7A of the slot 7. In the groove A of the slot 7, for example, an ultrafine film waterproof tape 11 in which a mixture of a water-absorbing resin and a synthetic resin is coated on both sides of a polyester film is accommodated together with the tape core.

FIG. 3 is a sectional view showing an example of the structure of the power cable. Outside the conductor 12, the inner conductive layer 13, the insulator layer 14, the outer conductive layer 15, the metal shielding layer 16, the waterproof tape 17, the PVC outer layer 1
8 are provided sequentially.

When the jacket of the cable having the above structure is deteriorated or damaged due to some accident, and water enters the cable, the waterproof tape disposed under the jacket passes through the jacket and enters. An excellent water stoppage that absorbs and expands water and stops water only near the infiltration point, preventing water running in the longitudinal direction or inside the cable, and preventing accidents due to cable water. Has a function.

Various types of tapes have been proposed as these cable waterproof tapes. For example, (1) a sandwich type in which a water-absorbent resin powder is interposed between two polyester long-fiber non-woven fabric sheets and integrated (Japanese Utility Model Application Laid-Open No. 59-47914).
JP-A-61-129228), (2) a type in which a water-absorbing paint obtained by mixing a powdery or granular water-absorbing resin and a resin binder is applied to one or both sides of a polyester long-fiber nonwoven fabric sheet (3) A mixed type in which a water-absorbent resin is contained in a matrix such as pulp fiber and reinforced with a mesh body (JP-A-61-163511). (4) A web composed of a water-absorbent fiber and a heat-bonded fiber is used. And nonwoven fabric sheets of water-absorbing fibers pressed with a hot roll (Japanese Utility Model Laid-Open No. 131012/1985).

<Problems to be Solved by the Invention> However, each of these conventional waterproof tapes has the following problems.

(1) Since the sandwich type water blocking tape has a hydrophobic polyester long fiber nonwoven fabric above and below the water-absorbent resin powder, when water invades, the water is absorbed by the water-absorbent resin powder. There is a drawback that it takes a little time and the running distance before stopping the water is long. In order to improve this, changing the basis weight of the upper and lower nonwoven fabrics has been performed,
In that case, it is difficult to determine the front and back sides and it is difficult to use. In addition, this type of waterproof tape does not have the water-absorbent resin powder adhered to the non-woven fabric, so when the wide sheet is cut into a tape of a practical width, or when taping to a cable, the tape is cut open or cut. Then, there is a problem that the water-absorbent resin powder falls off from the end of the tape.

(2) Since the water-absorbent resin powder is fixed with a binder, the water-absorbent resin powder has an advantage that the water-absorbent resin powder does not fall off from the end of the tape when the wide sheet is cut or cut into a tape shape. . However, since the water-absorbent resin powder is completely covered with the hydrophobic resin binder, when it comes into contact with water that has penetrated into the cable, its wettability with water is poor, and it takes time for the water-absorbent resin powder to absorb water. However, there is a drawback that the running distance until water stops is long.

(3) The water-blocking tape of the mixed type has hydrophilic pulp fibers and water-absorbent resin powder exposed on the front and back, so that when water enters the cable, it immediately absorbs water and swells, stopping almost instantly. There is an advantage that the running distance until water is stopped and stopped is very short. However, since the water-absorbing layer composed of the pulp fiber and the water-absorbent resin powder is not fixed, there is a problem that the pulp fiber and the water-absorbent resin powder fall off from the end of the tape when the wide sheet is cut into a tape shape or cut. In addition, the pulp fiber and the water-swellable substance are biodegradable, and have a fatal defect that the water-stop tape is decomposed by microorganisms during long-term use of the cable to generate hydrogen gas, which adversely affects the cable life. . In addition, the biodegradable water-absorbing and swelling substance based on natural products is gradually decomposed, and eventually loses its water-absorbing ability, and does not exhibit a water-stopping effect for a long time.

(4) Water-stopping tapes made of a non-woven fabric sheet of water-absorbing fibers include rayon-based fibers and water-absorbing acrylic-based fibers as the water-absorbing fibers, but since the non-woven fabric sheet is formed from short fibers, the tensile strength is low. However, it does not withstand the tension during taping of the cable and requires some reinforcement. The water-absorbent nonwoven fabric made of water-absorbing rayon fiber has a high water absorption rate and a high water absorption ratio, so that when water enters the cable, it absorbs water immediately and swells out, stopping water at a short running distance. Although it has a water stopping effect, it has a fatal defect that the water-absorbing rayon fiber is biodegradable. On the other hand, the water-absorbent non-woven fabric made of water-absorbent acrylic fiber has no microbial decomposability, and when water enters the cable, it absorbs water immediately and swells out to stop water at a short running distance. Although it has a water effect, it has a drawback in that the stopped water gradually runs over time and runs over a long distance because of a low water absorption ratio, and is expensive.

An object of the present invention is to solve the above-mentioned problems of the conventional water-blocking tape, and to generate hydrogen gas and halogen gas that adversely affect the optical fiber and copper even when used for a long period of time. The water-absorbing ability did not decrease for a long time, the water-absorbing resin powder did not fall off from the end when tape-shaped cutting and taping to an optical cable, had sufficient strength, and water entered the cable In this case, a water-stop tape for a cable that can be used for a long period of time is provided that instantaneously absorbs and swells to stop water only in the vicinity of a water infiltration point, thereby preventing water from running in the cable in the longitudinal direction and the internal direction. It is in.

<Means for Solving the Problems> The water-stopping tape for a cable of the present invention that achieves the above object has a biodegradable property on one or both sides of a synthetic resin film or a substrate made of a synthetic fiber woven or nonwoven sheet. It is characterized in that a cushioning water-absorbing paint composed of a powdery or granular water-absorbent resin, a binder of a synthetic resin or a synthetic rubber and short fibers of synthetic fibers is applied.

The substrate used in the present invention is a synthetic material that has strength enough to withstand the tension during water absorption processing and cable winding, is not decomposed by microorganisms, and preferably has flexibility. Therefore, a synthetic resin film or a woven or non-woven fabric of synthetic fibers can be used as the substrate. As the synthetic resin film, a polyester film, a polypropylene film, a polyamide film, a polycarbonate film, and a polybutene-1 film having a thickness of 25 to 100 µ are suitable. As the synthetic fiber woven or nonwoven fabric sheet, polypropylene, nylon, polyester, and acrylic can be used from the viewpoint of the material, but from the viewpoint of price and strength, a long-fiber nonwoven fabric produced by a spunbond method is advantageous.

The powdery or granular water-absorbing resin used in the present invention is a synthetic polymer having a water absorbing capacity of several tens to several thousand times its own weight without dissolving in water when contacted with water, and having no biodegradability. % Synthetic products, for example,
Acrylate-based crosslinked product, saponified vinyl acetate / acrylic acid ester copolymer, polyvinyl alcohol / maleic anhydride reactant, crosslinked isobutylene / maleic acid copolymer, acrylic acid / vinyl alcohol copolymer, acrylic Acid salt / acrylamide copolymer, modified polyethylene oxide, and the like are preferable.

The synthetic resin or synthetic rubber binder used in the present invention has a function of preventing the water-absorbent resin powder from falling off and adhering the water-absorbent resin powder to the base material, and is 100% synthetic without microbial degradability. Goods. Here, as the synthetic resin or synthetic rubber, in particular, acrylic resin, polyurethane resin, unsaturated polyester resin, ethylene copolymer resin, polyamide resin, polyisobutylene rubber, butyl rubber, ethylene propylene rubber, acrylic rubber, etc. Which do not contain a halogen atom are preferred. When a binder containing a halogen atom is used, harmful substances such as hydrochloric acid which adversely affect optical fibers and copper are released during long-term use.

The amount of the binder is preferably 10 to 200 parts by weight based on 100 parts by weight of the water absorbent resin. If the amount exceeds 200 parts by weight, the binder is too much for the water-absorbing resin, so that the water stopping effect is not exhibited. If the amount is less than 10 parts by weight, the effect of preventing the binder from falling off is not exhibited.

As a major feature of the present invention, a synthetic fiber short fiber is blended into the water-absorbing paint, and the synthetic fiber short fiber is dispersed in the water-absorbing paint to make the water-absorbing paint, which originally exhibits Newtonian fluidity, thixotropic fluidity. Change, reduce the shrinkage of the coating when applying the water-absorbing paint and drying the organic solvent, form fine water passages (voids) in the dried coating and thicken the dried coating to improve cushioning Is given. As the short fiber of the synthetic fiber, it is a synthetic substance having no biodegradability, and the material is preferably polypropylene, nylon, acryl, or polyester, and the thickness of the fiber is 0.5 to 5 denyl, and the length of the fiber is 1 to 1. 10 mm is preferred.

The compounding amount of the short fibers of the synthetic fibers is preferably 1 to 20 parts by weight based on 100 parts by weight of the water absorbent resin. If the amount is less than 1 part by weight, shrinkage of the coating film during drying of the coating film is large, and the effect of forming a fine water conduit is lost, and the cushioning property of the present invention cannot be obtained. If the amount is more than 20 parts by weight, the fluidity of the water-absorbing paint will be remarkably deteriorated, and it will not be possible to apply it uniformly to the substrate.

The cushioning water-absorbing paint used in the present invention is dissolved and dispersed in an organic solvent to be applied to one or both surfaces of the substrate. As the organic solvent, those capable of dissolving the above-mentioned synthetic resin or synthetic rubber as a binder can be used.For example, toluene, xylene, benzene, methyl ethyl ketone, acetone, hexane, methyl isobutylene, ethyl acetate, dioxane, tetrahydrofuran, cyclohexane, General purpose solvents such as alcohols are preferred.

The cushioning water-absorbing paint applied to the base material of the present invention is obtained by dissolving a synthetic resin or synthetic rubber binder in an organic solvent, adding a water-absorbent resin powder and synthetic fiber short fibers, and dispersing the mixture under stirring. Prepared. The prepared water-absorbing paint is applied to one or both sides of the substrate by a known coating method and dried to obtain the water-stopping tape for a cable of the present invention.

Next, the water blocking tape for cables of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a cross-sectional structure of a water-stopping tape for a cable according to the present invention. The waterproofing tape for cables of the present invention,
A water-absorbing layer 5 formed by applying and drying the water-absorbing paint of the present invention is provided on both sides of a synthetic resin film or a woven or non-woven fabric sheet 4 of synthetic fiber, and the water-absorbing layer 5 is powdery or granular biodegradable. It is composed of a water-absorbent resin 1 having no fibers, short fibers 2 of synthetic fibers, and a binder 3. The water-absorbing layer 5 of the water-stopping tape for a cable according to the present invention further contains the synthetic short fibers 2 as compared with the water-absorbing layer composed of the water-absorbing resin powder 1 and the binder 3 of the prior art. Sometimes it is very bulky, thick, rich in cushioning, and flexible. Because of the bulkiness, the water absorbing layer contains fine water passages formed by short fibers. Therefore, in the cable using the water-stopping tape for a cable of the present invention, the gap in the cable structure can be made extremely small due to the cushioning effect of the tape, and as a result, the internal space (water running gap) in the cable structure becomes very small. Can be reduced. Further, in the water-stopping tape of the prior art, the water that has penetrated into the cable is sequentially absorbed from the surface of the water-absorbing layer and expands, whereas in the water-stopping tape for a cable of the present invention, the fine water guide of the water-absorbing layer is provided. Water spreads throughout the water-absorbing layer and the entire water-absorbent resin in the water-absorbing layer instantly absorbs water and expands, thereby exhibiting excellent initial water stopping performance. Therefore, it is possible to stop the water running in the longitudinal direction and the inner direction of the cable only in the vicinity of the entry point of the water. In addition, since the water-absorbing resin powder of the present invention is fixed by a hinder, the water-absorbing resin powder does not fall off at the time of cutting and cable manufacturing, and is not decomposed by microorganisms. It does not generate harmful hydrogen gas and contains no halogen compounds, so it has a long-term reliability of several decades, and has a high tensile strength in the longitudinal direction, so it has excellent workability that can be easily applied to cables. Having. Further, the water-stopping tape for a cable of the present invention can be used not only as a communication cable of an optical fiber or a copper conductor, but also as a restraining winding of a power cable, and has a very wide application range and is extremely useful in practical use.

<Example> Next, an example of the present invention will be described.

100 parts by weight of butyl rubber heated to 50 ° C for test 2
The rubber was masticated between the rolls, and kneaded while gradually adding 15 parts by weight of polyester cut fiber (1.5 denyl × 3 mm length) to the butyl rubber to obtain a rubber sheet. The rubber sheet was cut into small pieces, placed in a container, added with 600 parts by weight of toluene, and allowed to stand overnight. The small pieces of the rubber sheet were swollen and stirred with a stirrer to obtain a rubber solution. To this rubber solution was added 250 parts by weight of a water-absorbent resin powder, AQUALIC CA-ML (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.), and 600 parts by weight of toluene, and sufficiently stirred and mixed to obtain a water-absorbing paint. This water-absorbing paint is applied to a polyester long-fiber nonwoven sheet (made by Asahi Kasei Corporation)
E1040: Coated on both sides with a basis weight of 40 g / m ² ) at a dry adhesion amount of 100 g / m ² , dried, and cut into a width of 25 mm to obtain a waterproof tape for cables of the present invention. Tape thickness is 0.4mm, unit weight is 140g /
It was m ^2.

(Comparative Example) 100 parts by weight of butyl rubber was heated to 50 ° C for test 2
It was masticated between the rolls to obtain a rubber sheet. The rubber sheet was cut into small pieces, placed in a container, 100 parts by weight of toluene was added, and the mixture was allowed to stand overnight. The small pieces of the rubber sheet were swollen and stirred with a stirrer to obtain a rubber solution. 250 parts by weight of water-absorbent resin powder Aquaric CA-ML (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) and 1200 parts by weight of toluene were added to this rubber solution, and thoroughly stirred and mixed to obtain a water-absorbing paint of the prior art. .
The water-absorbing coating by applying and drying a dry coating weight 100 g / m ² on both surfaces of the polyester filament nonwoven sheet of the same embodiment,
The tape was cut into a width of 25 mm to obtain a conventional waterproof tape for cables. The thickness of the tape was 0.3 mm, and the unit weight was 140 g / m ² .

(Test Example) In order to examine the water stopping effect of the cable waterproofing tape of the present invention obtained in the example and the conventional cable waterproofing tape obtained in the comparative example, the following simulation test was performed.

That is, a 25 mm diameter, 1.5 mm length linear glass rod
A waterproof tape having a width of mm was spirally wound on a half wrap. The glass rod around which the water blocking tape was wound was inserted into a glass tube having an inner diameter of 11 mm and a length of 1.5 m, and was fixed so that the glass rod was held at the center of the glass tube. Next, the composite glass tube was placed horizontally on a table, and tap water collected in the container was drained into the glass tube from a distance of 1.2 m in height from one side of the glass tube through the tube. As a result, the water stop tape of the example was completely stopped at a water running distance of 30 cm. After leaving it for 10 days in this state, the water running distance was 30 cm, which was not different from that immediately after water infiltration. On the other hand, the water stopping tape of the comparative example stopped at a water running distance of 60 cm, but when left as it was for 10 days, the water running distance was 70 cm, which was longer than immediately after water infiltration.

<Effect of the Invention> The water-blocking tape for a cable of the present invention, compared to the water-blocking tape of the prior art, contains a synthetic fiber short fiber in the water-absorbing layer. Thick, bulky and rich in cushioning. Because of the bulkiness, the water absorbing layer contains fine water passages formed by short fibers. Therefore, in the cable using the water-stopping tape for a cable of the present invention, the gap in the cable structure can be made extremely small due to the cushioning effect of the tape, and as a result, the internal space (water running gap) in the cable structure becomes very small. Can be reduced.
Further, in the water-stopping tape of the prior art, the water that has penetrated into the cable is sequentially absorbed from the surface of the water-absorbing layer and expands, whereas in the water-stopping tape for a cable of the present invention, the fine water guide of the water-absorbing layer is provided. The water spreads throughout the water-absorbing layer through the water, and the entire water-absorbing resin in the water-absorbing layer instantly absorbs water and expands.
Demonstrates excellent initial water stopping performance. Therefore, it is possible to prevent water running in the longitudinal direction and the inner direction of the cable, and to have an excellent water stopping performance that water can be stopped only in the vicinity of a water entry point.

The water-stopping tape for a cable of the present invention is characterized in that a water-absorbent resin powder and short fibers of synthetic fibers adhere to one or both sides of a synthetic resin film or a woven or non-woven fabric of synthetic fibers via a synthetic resin or synthetic rubber binder. It is fixed and made of 100% synthetic, so it is not decomposed by microorganisms to generate hydrogen gas, does not decrease water absorption capacity, and contains no halogen atoms, so it generates harmful substances such as hydrochloric acid. And can be used for a long time. Since the base material is a synthetic resin film or a woven or nonwoven fabric sheet of synthetic fibers, it has sufficient strength to withstand taping tension to the cable, and is very flexible. Moreover, the water-absorbing resin powder or particles do not fall off the water-stopping tape during processing,
It is possible to obtain a practically useful waterproof tape for cables.

The water-stopping tape for cables of the present invention can be used not only for communication cables including optical fiber cables but also for power cables, and for wide-width ones, sanitary products and water-absorbent sheets for disposable diapers, freshness of fruits and vegetables, fresh fish and raw meat, etc. It can be used as a holding material, a dew condensation prevention sheet, a sealing material, a medical dressing material, and the like, and its application range is extremely large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an example of a waterproof tape for cables of the present invention. FIG. 2 is a cross-sectional view schematically illustrating an example of an optical fiber communication cable to which a waterproof tape for cable is applied, and FIG. 3 is a cross-sectional view schematically illustrating an example of an electric power cable to which a waterproof tape for cable is applied. The figure is shown. 1: Water absorbing resin powder 2: Synthetic fiber short fiber 3: Synthetic resin or synthetic rubber binder 4: Substrate (synthetic resin film or woven or non-woven sheet made of synthetic fiber) 5: Water absorbing layer 6: Tensile body 7: Slot with polyethylene with groove 7a: Groove 8: Waterproof tape 9: Polyethylene jacket 10: Optical fiber tape core wire 11: Ultrafine film watertight tape 12: Conductor 13: Internal conductive layer 14: Insulator layer 15: External Conductive layer 16: Metal shielding layer 17: Waterproof tape 18: PVC outer layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01B 7/28 G02B 6/00, 6/44

Claims (1)

(57) [Claims] 1. One or both sides of a substrate made of a synthetic resin film or a woven or non-woven fabric sheet of synthetic fiber,
What is claimed is: 1. A water-stop tape for a cable, which is coated with a cushioning water-absorbing paint made of a powdery or granular water-absorbent resin having no microbial decomposability, a binder of a synthetic resin or a synthetic rubber, and short fibers of synthetic fibers.