JPH08167329A - Buoyancy cable - Google Patents

Abstract

PURPOSE: To improve buoyancy, bending resistance, external damage resistance and production efficiency by using polyolefin or a olefin family thermoplastic elastomer having a prescribed specific gravity and bending elastic modulus in a lump sheath covering a wire core part. CONSTITUTION: Several power wire cores 1 and optical fiber cores 2 are twisted to form a wire core part, an interposition 4 is directly placed thereon, then a lump sheath 6 is arranged thereon. The lump sheath 6 is formed with polyolefin or olefin family thermoplastic elastomer having a specific gravity of 0.8-0.95 and a bending elastic modulus of 4000-7000kg/cm<2> . The specific gravity of the whole cable is reduced, buoyancy as a buoyancy cable is maintained, bending resistance and external damage resistance are improved. Use of a high foam resin body for maintaining buoyancy is made unnecessary, an extrusion covering process is reduced to one process and production efficiency is remarkably improved.

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, and more particularly to a cable having excellent bending resistance and external damage resistance.

[0002]

2. Description of the Related Art As a conventional 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. An inner sheath 3 is coated on the outer side of the core portion formed by twisting the power cores 1 ... And the optical fiber cores 2. Outside the inner sheath 3,
The interposition 4 is provided, and the outer sheath 5 is further covered to form a buoyancy cable.

In the buoyancy cable as described above, the inner sheath 3 has a high resin foam (expansion ratio of 20 times or more).
Is generally used, which reduces the specific gravity of the entire cable and maintains the buoyancy of the cable. Further, by using high-strength rubber for the outer sheath 5, the buoyancy cable is provided with bending resistance so as not to be deteriorated even during repeated feeding and winding operations.

However, in such a buoyancy cable, since the resin high foam is used as the inner sheath in order to reduce the specific gravity of the cable, it is necessary to further provide the outer sheath. There is a drawback in that the manufacturing efficiency is poor because the outer sheath and the two extrusion processes 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 is good in flex resistance, but inferior in trauma resistance. Therefore, a buoyancy cable excellent in both flex resistance and trauma resistance cannot be obtained. Was wanted.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a buoyancy cable having sufficient buoyancy, good manufacturing efficiency, and excellent flex resistance and external damage resistance.

[0007]

[Means for Solving the Problems] The problem is to provide a single sheath on the wire core with a polyolefin or olefinic thermoplastic elastomer having a specific gravity of 0.8 to 0.95 and a flexural modulus of 4000 to 7000 kg / cm ^2. It is solved by forming using.

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of the buoyancy cable of the present invention. The power core 1 ... and the optical fiber core 2 ... It is similar to that of the conventional buoyancy cable shown in FIG. The buoyancy cable of the present invention is different from the conventional product in that an intervening member 4 is directly provided on the core portion and a collective sheath 6 is provided in place of the inner sheath 3 and the outer sheath 5 in FIG.

The collective sheath 6 has a specific gravity of 0.8 to 0.9.
No. 5, which is formed using a polyolefin or an olefin-based thermoplastic elastomer having a flexural modulus of 4000 to 7000 kg / cm ² . It should be noted that the volume of the power core is limited to only a portion in which the power cores 1 ... And the optical fiber cores 2 are twisted into one by one.
..., the optical fiber core 2, ..., and the space between the interposition 4 and the volume of the interposition 4 are not included.

In the buoyancy cable of the present invention, as described above, by forming the collective sheath using a resin having a specific gravity of 0.8 to 0.95, the specific gravity of the entire cable can be reduced and the buoyancy cable can be made smaller. It is possible to maintain its buoyancy.

Further, as described above, since it is not necessary to use the resin high-foam body 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 high strength rubber in conventional products, it is desirable to use polyolefin or olefinic thermoplastic elastomer in the above-mentioned collective sheath. However, it is most preferable to use a polyolefin or an olefin-based thermoplastic elastomer having a flexural modulus of 4000 to 7000 kg / cm ² .

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 6 is extruded and coated on the wire core portion, and the remaining collective sheath 6 is further provided on the core portion via a braided interposition 4.

The action 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 created with an outer sheath of strong rubber. (Comparative Example) A buoyancy cable was prepared in the same manner as the conventional example except that the outer sheath was formed of polyurethane resin.

(Example 1) A buoyancy cable was prepared by forming a core portion in the same manner as in Conventional Example 1 and providing a collective sheath made of polyurethane resin on the surface of the core portion. (Example 2) A buoyancy cable was produced in the same manner as in Example 1 except that the collective sheath was formed by using the polyolefin resin I. (Example 3) A buoyancy cable was produced in the same manner as in Example 1 except that the collective sheath was formed using polyolefin resin II. (Example 4) A buoyancy cable was produced in the same manner as in Example 1 except that the collective sheath was formed using an olefinic thermoplastic elastomer (TPO).

With respect to the above-mentioned conventional example and comparative example, the specific gravity,
Tensile strength, elongation and hardness were measured, and the scratch resistance was evaluated. The results are shown in Table 1. A JIS Durometer A for soft plastics (needle load: 822 g) was used to measure the hardness.

[0017]

[Table 1]

With respect to the above-mentioned conventional examples and Examples 1 to 4, the specific gravity, tensile strength, elongation rate, hardness, flexural modulus, and dynamic friction coefficient were measured, and the scratch resistance and flex resistance were evaluated. The results are shown in Table 2. In addition,
A Shore durometer for hard plastics D type (needle load: 4.536 kg) was used to measure the hardness.

[0019]

[Table 2]

Regarding the above-mentioned external damage resistance, the following tests are carried out: Test method: NEMA type abrasion tester (reciprocating abrasion using a V-shaped blade) Conditions: reciprocating distance 10 mm, speed 60 times / min. An evaluation was performed. Damage resistance (number of times of durability) ◎:> 5000 times / mm ○:> 3000 times / mm △: 1000 to 2000 times / mm ×: <1000 times / mm

Further, the following test was carried out for the flex resistance, 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

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

From the results shown in Table 2, Example 1 has improved external damage resistance and good bending resistance, but since the specific gravity of the polyurethane used for the collective sheath is 1.12. This cable is difficult to maintain buoyancy. In addition, in Example 2, the polyolefin I used for the collective sheath was used.
Has a specific gravity of 0.91, which is within a desirable range, and has significantly improved external damage resistance, but it has poor flexibility and a short period of time due to repeated feeding and winding operations. Is expected to deteriorate with use.

On the other hand, in Examples 3 and 4, the specific gravities of the polyolefin II and TPO used for the collective sheath were both 0.89, which were within the desired range, and the trauma resistance was remarkably improved. To be In addition, with respect to the bending resistance, the result satisfying the required characteristics was obtained.

When the above results are summed up, the specific gravity is 0.8 to
Within the range of 0.95, the flexural modulus is 4000 to 70.
Polyolefin II and TP in the range of 00 kg / cm ²
It was found that Examples 3 and 4 in which O was used could easily maintain buoyancy and had excellent flex resistance and external damage resistance. In addition, compared with the conventional example having a 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.

[0026]

As described above, in the buoyancy cable of the present invention, the collective sheath has the specific gravity of 0.8 to 0.
Polyolefin or olefinic thermoplastic elastomer (TP having a flexural modulus of 4000 to 7000 kg / cm ² at 95 (TP
It is a buoyancy cable formed using O).

The buoyancy cable of the present invention has a specific gravity of 0.
8 to 0.95 has a buoyancy by forming a collective sheath using a polyolefin or an olefinic plastic elastomer, and has a flexural modulus of 4000 to 70 as the polyolefin or the olefinic plastic elastomer.
It is a buoyancy cable that has excellent flex resistance by selecting and using 00 kg / cm ² and also has excellent external damage resistance. Further, since the buoyancy cable of the present invention is coated as a collective sheath instead of the conventional two-layer coating structure, the number of manufacturing steps is reduced and the manufacturing efficiency is remarkably 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.

[Explanation of symbols]

 1 ... power core, 2 ... optical fiber core, 6 ... collective sheath.

Claims (1)

[Claims] 1. A buoyancy cable in which a collective sheath is provided on the core portion formed by twisting several power cores and optical fiber cores together, and the specific gravity of the collective sheath is 0.
A buoyancy cable characterized by using a polyolefin or an olefin-based thermoplastic elastomer having a flexural modulus of 4000 to 7000 kg / cm ² at 8 to 0.95.