JPH06309945A - Water stopping tape - Google Patents

Abstract

PURPOSE:To provide a water stop tape exerting an excellent water stopping performance. CONSTITUTION:A water stop tape is formed by providing a water absorbing layer 2 on either or both of the surfaces of a base material 1, which is made from a nonwoven cloth chiefly consisting of resin fibers having flat section. This greatly reduces water intrusion and penetration in the vertical direction of the tape, so that it exerts a surprisingly high running water preventing performance, being 30 times as large as that of a conventional water stop tape using a nonwoven fabric having a circular fiber section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an optical fiber cable,
The present invention relates to a water stopping tape for running water prevention used for the purpose of imparting water impermeability in electric cables and the like.

[0002]

2. Description of the Related Art Conventionally, in a communication cable such as an optical fiber cable, a power cable or the like, water that has entered from the outside due to damage to the cable jacket or the like runs inside the cable (this phenomenon is usually called "running water"). It is known in the art to use water-blocking tape under the cable jacket to prevent "running water"). As shown in FIG. 1, this waterproofing tape basically has a structure in which a water absorbing layer 2 containing a water absorbing resin is provided on one surface or both surfaces of a base material 1, and when the outer jacket of the cable is damaged, The water absorbing layer 2 absorbs the water that has entered, and the water absorbing layer 2 swells and gels, filling the voids in the cable and preventing the invading water from running in the cable in the longitudinal direction. It is a thing.

A water-stop tape used for such a purpose is a water-swelling swell consisting of a mixture of two highly absorbent water-absorbent resin powder particles and a low-melting adhesive resin powder particle. Having a plurality of layers, the base nonwoven fabric between each water-swelling layer,
A sandwich type water blocking tape (Japanese Patent Laid-Open No. 63-301418) or a polyester long-fiber non-woven fabric sheet mixed with a powdery or granular water-absorbing substance and a binder resin. A water-stop tape (Japanese Utility Model Publication No. 61-129228) having a coating type water-absorbing layer formed by coating and drying a coating liquid has been proposed.

[0004]

The water-absorbent material that forms the water-absorbent layer of the water-stop tape is mainly composed of a water-absorbent resin and a binder. In order to shorten the running distance, it is necessary to improve the water absorbing performance of this water absorbing material, and for that purpose, it is desirable to reduce the ratio of the binder in the water absorbing material as much as possible. On the other hand, when the amount of the binder is small, the adhesiveness to the base material is deteriorated. Therefore, in order to secure the adhering amount of the water absorbing material to the base material, a non-woven fabric is used as the tape base material as in the conventional example. However, in the conventional waterproof tape using a non-woven fabric as the base material, the non-woven fabric itself easily allows water to permeate, so even if only the cable jacket is damaged, the invading water is the base layer of the waterproof tape. There is a drawback that it easily penetrates the water absorption layer vertically and flows into the inside of the cable. In order to prevent water permeation of the non-woven fabric, as a water-absorbing material applied to the non-woven fabric of the base material,
It is effective to use a high content ratio of the binder resin that is non-water-absorbing, but the water-absorbing layer using the water-absorbing material with a high content ratio of the binder resin has a poor water-absorbing performance, and the invaded water There is a drawback that the running distance in the longitudinal direction becomes long. It is also conceivable to use a plastic film as the base material to prevent the water penetration tape from penetrating water in the vertical direction, but if the plastic film is used as the base material, the water absorption layer will easily peel off and There is a drawback in that the water-absorbent layer is easily cracked when the tape is manufactured or used.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have mentioned the above-mentioned drawbacks found in a conventional waterproof tape using a nonwoven fabric as a base material.
That is, paying attention to the drawback that water easily penetrates through the waterproof tape in the vertical direction and reduces the penetration of water in the vertical direction of the waterproof tape without impairing the water absorption performance of the water-absorbing layer. As a result of diligent study to develop a waterproof tape that can
The present invention has been completed. That is, the water blocking tape of the present invention is a water blocking tape in which a water absorbing layer is provided on one side or both sides of a base material, wherein the base material is a non-woven fabric mainly composed of resin fibers having a flat cross section. It is characterized by.

In the present invention, the non-woven fabric used as the substrate is mainly composed of resin fibers having a flat cross section, and the basis weight of the resin fibers in the non-woven fabric is 30 g / m ² or more and the thickness is Those having a thickness of 0.05 mm or more are preferable in terms of strength, adhesion of a water absorbing substance, and water blocking property. Also,
Examples of the material of the resin fiber include materials such as polyester, polyamide, polyolefin, rayon, and vinylon. From the viewpoint of strength and heat resistance, a polyester-based or polypropylene-based spunbonded nonwoven fabric is preferable. An example of the non-woven fabric mainly composed of fibers having a flat cross section is, for example, manufactured by Unitika Ltd. under the trade name 2070.
1 FLV (basis weight 70 g / m ² , polyester spun bond), trade name 20551 FLV (basis weight 55 g / m ² ,
Polyester spun bond), product name 20457FL
V (basis weight: 45 g / m ² , spunbond made of polyester) and the like are commercially available.

In the present invention, the powder or granular water-absorbent resin used in the water-absorbing layer does not melt when it comes into contact with water, and has a water-absorbing capacity of several ten times to several thousand times its own weight. Any polymer can be used as long as it is a 100% synthetic product which is not biodegradable, and is not limited to any particular product. Examples of such products include cross-linked acrylates, acrylate / acrylamide copolymers, polyvinyl alcohol / maleic anhydride reaction products,
There are saponified vinyl acetate / acrylic acid ester copolymers, polyethylene oxide modified products, isobutylene / maleic anhydride copolymers, etc.
Alternatively, two or more of these can be used in combination. This water-absorbent resin is used as a mixture with the binder resin, and the compounding amount thereof is preferably in the range of 20 to 1500 parts by weight with respect to 100 parts by weight of the binder. If the amount is less than 20 parts by weight with respect to 100 parts by weight of the binder, a good water-stopping effect is not exhibited, and if the amount is more than 1500 parts by weight, the water-absorbing layer composed of the resulting composition is It becomes easy to fall off the material tape.

As the binder, a synthetic resin or synthetic rubber which is not biodegradable is used. For example, acrylic acid resin, polyurethane resin, unsaturated polyester resin, polyethylene resin, polyamide resin, silicone resin. , Polyisobutylene, butyl rubber,
Acrylic rubber, ethylene propylene rubber, and the like that do not contain a halogen atom are preferable. The water absorbing material used in the water absorbing layer in the present invention is a powder or granular water absorbing resin and a binder, and if necessary, a crosslinking agent or a vulcanizing agent,
It can be prepared by dissolving and dispersing in an organic solvent one or more substances selected from the group consisting of a rust preventive, a wetting agent, a flame retardant, a filler, and a conductive substance to prepare a paint. .
As the organic solvent used for this purpose, general-purpose solvents such as toluene, xylene, benzene, methyl ethyl ketone, acetone, hexane, dioxane, tetrahydrofuran, cyclohexane, alcohol can be used.

[0009]

The non-woven fabric used as the base material of the waterproof tape is a non-woven fabric having a flat cross section and is formed by a calender roll or the like. The contact area is large and the structure is more dense. Therefore, the water permeability of the water blocking tape in the vertical direction is hindered accordingly. Furthermore, when compression molding is performed in the thickness direction with a calender roll or the like, the densification of the resin fiber proceeds, and the penetration of water in the vertical direction of the water blocking tape can be significantly prevented. Hereinafter, the water blocking tape of the present invention will be specifically described with reference to examples.

[0010]

【Example】

Examples 1 to 3 and Comparative Examples 1 to 2 Each of the non-woven fabrics having the configurations shown in Table 1 was used as a substrate, and a water-absorbing material having the composition shown in Table 2 on one side thereof was 100 in terms of solid content.
After coating and drying so as to be g / m ² , Examples 1 to 3 and Comparative Example 1 were obtained by cutting into a tape body having a width of 30 mm.
The water blocking tapes of ~ 2 were produced.

[0011]

[Table 1]

[0012]

[Table 2] * 1 Product name Aqualic CS-6HM [manufactured by Nippon Shokubai Co., Ltd.] * 2 Product name Toa Akron PS-250 [manufactured by Toa Paint Co., Ltd.]

A T-shaped water running test was carried out using each of the water blocking tapes produced in the above-mentioned constitution. Note that the T-shaped water running test is a test assuming water intrusion from the side surface of the cable due to damage to the cable jacket or the like. The test method is such that the optical fiber tape core wire is arranged in the groove portion of the slot type spacer, and 1/2 of the first water blocking tape is provided on the outer periphery thereof.
A press-wrapping layer formed by wrapping, a 1 / 2-wrap winding layer of vinyl tape for waterproofing, and a press-wrapping layer formed by 1 / 2-wrap winding of the second waterproof tape are sequentially provided on the outer periphery thereof. An optical fiber cable with an outer cover is made, and as shown in FIG. 2, the outer cover of the intermediate portion 4 of the cable 3 is removed by about 25 mm, and the second winding tape is used as the press-winding layer 5. The exposed seam is exposed on this part, and the artificial seawater 6 at a room temperature with a head length of 1 m is formed at this temperature.
Water is injected into the cable of 1.5 m on each side, and the running water is measured after 24 hours. The results obtained are shown in Table 3.

[0014]

[Table 3]

As is clear from Table 3, the water-stop tape of the present invention, which uses as a base material a non-woven fabric made of resin fibers having a flat cross section as a raw material, is a water-stop tape in the vertical direction. As a result of remarkably reducing the penetration penetration, the water running prevention performance was 30 times or more as compared with the conventional water blocking tape using a nonwoven fabric having a circular fiber cross section.

[0016]

EFFECTS OF THE INVENTION The water blocking tape of the present invention has a significantly reduced penetration of water in the vertical direction of the water blocking tape.
Compared with the conventional water-stop tape using a nonwoven fabric having a circular fiber cross section, the water-stopping performance is 30 times or more astonishing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a water blocking tape.

FIG. 2 is an explanatory diagram for explaining a T-shaped water running test method.

[Explanation of symbols]

 1 ... Base material of water blocking tape 2 ... Water absorption layer of water blocking tape 3 ... Optical fiber cable 4 ... Intermediate part 5 ... Rolled layer 6 ... Artificial seawater

Claims (1)

[Claims] 1. A water blocking tape having a water absorbing layer on one or both sides of a base material, wherein the base material is a non-woven fabric mainly composed of resin fibers having a flat cross section. .