JPH08264019A - Coating material and floating cable having sheath made of this coating material - Google Patents

Abstract

PURPOSE: To provide a floating cable by using the coating material for giving excellent bending resistance and damage resistance to the cable. CONSTITUTION: Olefin group thermoplastic elastomer at 2,000-5,000kg/cm<2> of bending elasticity and polypropylene at 10,000-16,000kg/cm<2> of bending elasticity are blended so as to obtain a specific gravity at about 0.89-1.0. A sheath is provided on a core part, which is formed by twisting several power cores and several optical fibers, by using this coating material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buoyancy cable used in, for example, a minesweeper, which is a covering material which imparts particularly excellent bending resistance and external damage resistance.

[0002]

2. Description of the Related Art Conventionally, as the buoyancy cable, the one illustrated in FIG. 3 is widely known. In FIG. 3, reference numeral 1 is a power line core, and reference numeral 2 is an optical fiber core. The power line cores 1 ... And the optical fiber line cores 2 ... Are twisted into a plurality of wires to form a wire core portion 3. An inner sheath 4 is filled and covered in the gap and the outside of the wire core portion 3. An intervening member 5 is provided on the outer side of the inner sheath 4 and is further covered with the outer sheath 6 to form a buoyancy cable.

As a covering material for the above buoyancy cable, a high resin foam (expansion ratio of 20 times or more) is used for the inner sheath 4 in order to reduce the specific gravity of the entire cable and maintain the buoyancy of the cable. Is common. Also,
The outer sheath 6 is made of high-strength rubber so as to have resistance to bending so that the buoyancy cable does not deteriorate even during repeated feeding and winding operations.

However, in such a buoyancy cable, it is necessary to provide an inner sheath of high resin foam in order to maintain the buoyancy of the cable and an outer sheath of high-strength rubber in order to impart bending resistance. Therefore, there is a drawback that the manufacturing efficiency is poor because two extrusion steps are required.

When a buoyancy cable of this type is used, the operations such as feeding or winding are repeatedly performed as described above, and the buoyancy cable rubs against the edge portions of the various parts of the apparatus, so that external There are many cases where the sheath is damaged and the quality of the buoyancy cable deteriorates.
This is because the high-strength rubber used for the outer sheath exhibits good bending resistance, but is inferior in external damage resistance. Under these circumstances, there has been a demand for a coating material that is excellent in both flex resistance and external damage resistance while maintaining the buoyancy of the cable and providing a buoyancy cable with less deterioration.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a coating material excellent in bending resistance and external damage resistance, and further to have sufficient buoyancy using this coating material and to improve manufacturing efficiency. It is to provide a buoyancy cable that is excellent in bending resistance and external damage resistance.

[0007]

This problem is solved by using a resin prepared by blending a thermoplastic polyolefin-based elastomer and polypropylene as a coating material. The buoyancy cable of the present invention maintains the buoyancy by using the above-mentioned coating material, and is improved in flex resistance and external damage resistance.

Hereinafter, the present invention will be described in detail. In the present invention, the olefinic thermoplastic elastomer has a flexural modulus of 2,000 to 5,000 kg / cm ² , and the polypropylene has a flexural modulus of 10,000.
The coating material is constituted by using the material of 0 to 16,000 kg / cm ² . It is desirable that the olefinic thermoplastic elastomer and the polypropylene are blended in a ratio of 9: 1 to 6: 4 and have a specific gravity of 0.89 to 1.

Since the covering material compounded as described above has a specific gravity of 0.89 to 1, it is possible to reduce the overall specific gravity of the cable using this covering material, and the conventional foamed product. It is possible to maintain the buoyancy of the cable without providing an inner sheath using.

Further, the above-mentioned coating material has both flex resistance and trauma resistance by using a mixture of an olefinic thermoplastic elastomer excellent in flex resistance and polypropylene excellent in trauma resistance. It is excellent. Therefore, if the covering material is used for the sheath of the buoyancy cable, the buoyancy cable can be provided with bending resistance and external damage resistance at the same time, and it is not necessary to provide a plurality of sheaths as in the conventional case.

FIG. 1 shows an example of a buoyancy cable using the above covering material, in which a plurality of power lines 1 and optical fiber lines 2 are twisted together into one line. The core 3 is similar to that of the conventional buoyancy cable shown in FIG. This buoyancy cable is different from the conventional product in that an intervening member 5 is directly provided on the core portion 3 and a collective sheath 7 is provided instead of the inner sheath 4 and the outer sheath 6 in FIG.

The collective sheath 7 is formed of a coating material made by blending a thermoplastic polyolefin-based elastomer and polypropylene, and the coating material has a specific gravity of 0.
It is compounded so as to be 89 to 1.0. It should be noted that the volume of the core portion 3 is limited to a portion in which the power cores 1 ... And the optical fiber cores 2 ... Fiber core 2
... and the space between the interposition 5 and the volume of the interposition 5 are not included.

In the buoyancy cable of the present invention, as described above, by forming the collective sheath using the covering material having a specific gravity of 0.89 to 1.0, the specific gravity of the entire cable can be reduced and the buoyancy force can be reduced. It is possible to maintain buoyancy as a cable.

Further, as described above, since it is not necessary to use the high resin foam for maintaining the buoyancy unlike the conventional product, it is not necessary to newly provide the outer sheath, and therefore, the conventional two-step extrusion coating process is performed. It can be shortened once, and it is possible to greatly improve the manufacturing efficiency.

In order to obtain excellent trauma resistance and flex resistance similar to that of conventional high-strength rubber, the above-mentioned one-piece sheath is coated with a mixture of a thermoplastic polyolefin elastomer and polyethylene. It is desirable to use a material, and in particular, the bending elastic modulus is 2,000 to
5,000 kg / cm ² of the olefinic thermoplastic elastomer and flexural modulus is most preferably used polypropylene 10,000~16,000kg / cm ^2.

It is also possible to use a thermoplastic polyolefin-based elastomer or polyethylene alone for the collective sheath, and whichever one is used, it is expected to have better scratch resistance than conventional high-strength rubber.

The buoyancy cable of the present invention is not limited to the structure shown in FIG. 1, and the structure shown in FIG. 2 is also suitable as in FIG. In FIG. 2, a part of the collective sheath 7 is extruded and coated on the wire core portion 3, and the remaining collective sheath 7 is further provided on the core portion 3 via a braided interposition 5.

The operation and effect will be clarified below by showing concrete examples. (Conventional example) Several power cores and optical fiber cores are twisted together to form a core, and an inner sheath made of high-resin foam is provided on the surface of this core, and the inner sheath A buoyancy cable was made with an outer sheath of strong rubber (EP). (Comparative Example) A buoyancy cable was prepared in the same manner as in the conventional example except that the outer sheath was formed of polyurethane resin (PU).

(Example 1) A core portion was provided in the same manner as in the conventional example, and 75 parts by weight of an olefinic thermoplastic elastomer (TPO) having a flexural modulus of 4000 kg / cm ² was applied to the surface of the core portion. A buoyancy cable was prepared by forming a collective sheath using a resin prepared by mixing 25 parts by weight of polypropylene (PP) having a rate of 16000 kg / cm ² .

Example 2 A buoyancy cable was prepared in the same manner as in Example 1 except that the olefin thermoplastic elastomer (TPO) having a flexural modulus of 4000 kg / cm ² was used alone to form a collective sheath. .

(Example 3) Flexural modulus 16000 kg / cm ²
A buoyancy cable was formed in the same manner as in Example 1 except that polypropylene (PP) was used alone to form the collective sheath.

Specific gravity, tensile strength, elongation rate, hardness, embrittlement temperature, and flex resistance of the above-mentioned conventional example, comparative example and each example were measured, and the results are shown in Table 1. A JIS Durometer A for soft plastics (needle load: 822 g) was used to measure the hardness.

[0023]

[Table 1]

With respect to the above-mentioned bending resistance, the following test was carried out, and the test method: the bending diameter was measured and evaluated according to the following criteria. Flexibility (R) ◎: R <50 cm ○: R <100 cm ×: R> 100 cm

Further, the following conventional tests, comparative examples and examples were carried out with respect to the external damage resistance test method: NEMA type abrasion tester (reciprocating wear using a V-shaped blade) Condition: reciprocating distance 10 mm, speed 60 times / minute The result is shown in FIG.

From the results shown in Table 1 and FIG. 4, the buoyancy cable of the comparative example is improved in the external damage resistance by forming the outer sheath from polyurethane, but the specific gravity of polyurethane is 1.12. Moreover, this cable proves difficult to maintain buoyancy.

In Example 1, the coating material prepared by blending the olefinic thermoplastic elastomer used for the collective sheath and polypropylene has a specific gravity of 0.91, which is within a desirable range, and the bending resistance and It can be seen that the trauma is also significantly improved. In Example 2, the specific gravity of the olefinic thermoplastic elastomer used for the collective sheath was 0.89.
It is understood that the values are within the desirable range, and the bending resistance and the external damage resistance are remarkably improved.

In Example 3, the specific gravity of polypropylene used for the collective sheath was 0.91, which was a value within a desirable range, and although it was particularly excellent in external damage resistance, it was slightly poor in flexibility, It is expected that deterioration due to short-term use due to repeated feeding and winding operations. Further, since polypropylene has a relatively high brittleness temperature of −5 ° C., it is understood that a sheath using polypropylene alone is not suitable for a cable that requires cold resistance.

Summarizing the above results, it was carried out using a coating material in which an olefinic thermoplastic elastomer and polypropylene were blended so that their specific gravity was 0.91 and the flexural modulus was 5,000 kg / cm ^2. It was found that Example 1 was easy to maintain buoyancy, and had excellent flex resistance and external damage resistance. Further, as compared with the conventional example having the two-layer coating structure, the example in which the collective sheath is provided was able to exert a remarkable effect in terms of improvement in manufacturing efficiency.

[0030]

As described above, the coating material of the present invention contains an olefinic thermoplastic elastomer and polypropylene and has a specific gravity of 0.89 to 1.0 and a bending elastic modulus of 4.
000 to 7,000 kg / cm ^2, and by using this covering material, it is possible to impart excellent bending resistance and external damage resistance to the buoyancy cable and to maintain the buoyancy of the buoyancy cable. It is something.

The buoyancy cable of the present invention has excellent bending resistance and external damage resistance by forming a collective sheath using the above-mentioned coating material. Furthermore, since the buoyancy cable of the present invention is coated as a collective sheath instead of the conventional two-layer coating structure, the manufacturing process is reduced,
Manufacturing efficiency is significantly improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a buoyancy cable of the present invention.

FIG. 2 is a cross-sectional view showing another example of the buoyancy cable of the present invention.

FIG. 3 is a sectional view showing an example of a conventional buoyancy cable.

FIG. 4 is a diagram comparing differences in external damage resistance due to coating materials in buoyancy cables.

[Explanation of symbols]

 1 ... power core, 2 ... optical fiber core, 7 ... collective sheath.

Claims (2)

[Claims] 1. A coating material comprising a thermoplastic polyolefin-based elastomer and polypropylene. 2. A buoyancy cable in which a collective sheath is provided on a core portion formed by twisting several power cores and optical fiber cores together, wherein the collective sheath has a covering material according to claim 1. Buoyancy cable characterized by using.