JP7108513B2 - CABTYRE CABLE AND CABTYRE CABLE MANUFACTURING METHOD - Google Patents

Description

The present invention relates to cabtyre cables.

2. Description of the Related Art Conventionally, cabtyre cables that can be routed in a conducting state have been used as electric wires that supply power to various industrial equipment such as industrial cranes, hoists, and welders (for example, Patent Document 1). A cabtyre cable is composed of a conductor, at least one wire core having an insulator covering the conductor, and a sheath covering the wire core. is used, and NR (natural) rubber is used for the core insulator and sheath. Some cabtyre cables for welders omit insulation from the core.

Japanese Patent Application Laid-Open No. 2007-12462

By the way, NR rubber has low weather resistance. Therefore, when a cabtire cable with a sheath made of NR rubber is used outdoors, cracks are likely to occur on the surface of the sheath. Therefore, the weather resistance of the sheath is usually improved by adding an antiozonant to NR rubber, which is the material of the sheath. However, antiozonants require careful handling, and consideration must also be given to their impact on the environment.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cabtyre cable excellent in weather resistance without using an antiozonant, and a method for manufacturing the same.

In order to solve the above-mentioned problems, the cabtire cable of the present invention is a blend rubber in which NR rubber , EP (ethylene propylene) rubber , and NBR (nitrile) rubber as a binder for EP rubber and NR rubber are compounded in the sheath. was used. This blend rubber is prepared by, for example, mixing NR rubber, carbon masterbatch of EP rubber and NBR rubber, carbon masterbatch of SBR (styrene butadiene), vulcanizing agent and vulcanization acceleration aid in a mixer. It may be manufactured by

Since EP rubber has better weather resistance than NR rubber, by using NR rubber and a blended rubber blended with EP rubber for the sheath, it is possible to eliminate the addition of anti-ozonants to the NR rubber that is the material of the sheath. However, the weatherability of the sheath can be improved. Therefore, according to the present invention, it is possible to provide a cabtyre cable excellent in weather resistance and a method for producing the same without using an antiozonant.

FIG. 1 is a schematic cross-sectional view of a cabtire cable 1 according to one embodiment of the invention. FIG. 2 is a diagram for explaining a flexibility test method for cabtyre cable 1 according to one embodiment of the present invention. FIG. 3 is a diagram showing a flexibility test result of cabtyre cable 1 according to one embodiment of the present invention. FIG. 4 is a diagram for explaining a wear resistance test method for materials used for the sheath 3 of the cabtire cable 1 according to one embodiment of the present invention.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a cabtire cable 1 according to this embodiment.

As illustrated, a cabtire cable 1 according to this embodiment includes at least one wire core 2 and a sheath 3 covering the wire core 2 .

The wire core 2 has a conductor 4 such as a tin-plated annealed copper stranded wire, an insulator 5 covering the conductor 4, and a separator 6 such as paper separating the conductor 4 and the insulator 5 from each other. Although FIG. 1 illustrates a so-called two-core type cabtyre cable 1 having two cores 2, the number of cores 2 may be one or three or more.

EP rubber mixed with talc as a filler is used for the insulator 5 . This EP rubber is compounded with a vulcanizing agent (or cross-linking agent) and a vulcanization accelerator aid (or cross-linking accelerator aid). If necessary, plasticizers such as naphthenic oils, fillers (extending materials) such as calcium carbonate and clay, and lubricity imparting agents such as paraffin for improving moldability are blended. The EP rubber may be either sulfur-vulcanized or peroxide-vulcanized. It is possible to further improve the performance.

The sheath 3 is made of a blend rubber containing NR rubber, EP rubber, NBR rubber, and SBR (styrene-butadiene) rubber. This blend rubber contains a vulcanizing agent (or cross-linking agent) and a vulcanization accelerator (or cross-linking accelerator). In addition, if necessary, a plasticizer such as naphthenic oil, a filler (extending agent) such as calcium carbonate, an antioxidant, and a dispersing agent such as stearic acid are blended. This blend rubber includes, for example, NR rubber, a carbon masterbatch of EPDM (ethylene propylene diene) rubber and NBR rubber as EP rubber, a carbon masterbatch of SBR, a vulcanizing agent (or a cross-linking agent) and a vulcanizing agent. An accelerator aid (or cross-linking accelerator aid) and, if necessary, a plasticizer such as naphthenic oil, a filler (extending agent) such as calcium carbonate, an antioxidant, and a dispersing agent such as stearic acid. It is made by mixing in a mixer. By compounding the NBR rubber, it functions as a binder between the NR rubber and the EP rubber, and the compatibility between the NR rubber and the EP rubber is improved, and the quality variation of the sheath 3 is reduced.

In the cabtyre cable 1 according to the present embodiment, the insulator 5 is made of EP rubber containing talc as a filler. EP rubber is superior in heat resistance to NR rubber. In addition, talc is a layered mineral containing magnesium as a main component. By blending talc with EP rubber as a filler, it accumulates in the EP rubber and increases the dimensional stability in the talc deposition direction, that is, in the thickness direction of the EP rubber. improve. Therefore, by using EP rubber mixed with talc as a filler for the insulator 5 of the wire core 2, the heat resistance and pressure resistance of the insulator 5 are improved. Also, the insulator 5 need not be thickened. Therefore, it is possible to prevent the cabtyre cable 1 from increasing in diameter, increasing in weight, and decreasing in flexibility.

In order to confirm the above points, the present inventors investigated a comparative product using NR rubber for the insulator 5 of the wire core 2 in the cabtire cable 1, and a cabtire cable 1 that achieves pressure resistance equivalent to that of the comparative product. A prototype of and was produced. However, the sheath 3, both the prototype and the comparative product, contains NR rubber, SBR rubber, a vulcanizing agent, a vulcanization accelerator aid, a plasticizer such as naphthenic oil, a filler such as calcium carbonate, an antioxidant, The same material containing an antiozonant and a dispersing agent such as stearic acid is used.

The comparative product has a rated temperature of 60°C, an allowable current of 19A, an outer diameter of 12.6mm, and a weight per unit length of 225g/m, while the prototype has a rated temperature of 80°C and an allowable current of 23A. It has an outer diameter of 11.1 mm and a weight per unit length of 180 g/m. It was confirmed that it can be realized.

Next, the present inventor conducted a flexibility test in the following manner, using each of the produced prototype and comparative product as test object 7 . Specifically, as shown in FIG. 2, the test object 7 is placed on the horizontal table 8 with the tip portion 70 of the test object 7 protruding horizontally from the end of the horizontal table 8 . Then, the deflection amount D of the tip portion 70 of the test object 7 was measured while changing the projection length L of the tip portion 70 of the test object 7 from the horizontal table 8 .

The test results of this flexibility test are shown in FIG. Here, the horizontal axis represents the projection length L (mm) of the tip portion 70 of the test object 7 and the vertical axis represents the amount of deflection D (mm) of the tip portion 70 of the test object 7 .

In FIG. 3, a solid-line graph 10 indicates the experimental results of the prototype, and a dotted-line graph 11 indicates the experimental results of the comparative product. As shown in the figure, the prototype has a greater amount of deflection D than the comparative product at any protrusion length L, and from this it was found that the prototype has higher flexibility than the comparative product.

Moreover, in the cabtire cable 1 according to the present embodiment, the sheath 3 is made of a blend rubber containing NR rubber, EP rubber, NBR rubber, and SBR rubber. Since EP rubber has better weather resistance than NR rubber, by using a blend rubber containing NR rubber and EP rubber for the sheath 3, the sheath can be used without adding an anti-ozonant to the NR rubber. The weather resistance of 3 can be improved. In addition, since NBR rubber and SBR rubber are excellent in abrasion resistance, the wear resistance of the sheath 3 can be improved by blending the NBR rubber and the SBR rubber into the blend rubber that is the material of the sheath 3. .

In order to confirm the above points, the present inventors used NR rubber, EP rubber (EPDM rubber), NBR rubber, SBR rubber, vulcanizing agents, vulcanization accelerator aids, plasticizers such as naphthenic oils, calcium carbonate, etc. A plate-shaped test piece (referred to as test piece A) made of a material containing a filler, an antioxidant, and a dispersing agent such as stearic acid, NR rubber, SBR rubber, vulcanizing agent, vulcanization acceleration aid A plate-shaped test piece (test piece B and ) were made with the same dimensions (length: 120 mm, width: 10 mm, thickness: 2 mm). Then, in a test environment with an ozone concentration of 50 pphm and a temperature of 40 ° C., the test pieces A and B are set to a static 40% elongation state (a state in which tension is applied and stretched by 40% from the natural length state) to prevent the occurrence of cracks. Observed. As a result, in the test piece B containing no EP rubber, many cracks with a length of 3 mm or more occurred on the surface after 24 hours, but in the test piece A, even after 72 hours, cracks were visually observed. No possible cracks occurred on the surface. From this, it was found that the test piece A containing the EP rubber had higher weather resistance than the test piece B containing the antiozonant.

Next, the present inventors found that NR rubber, EP rubber (EPDM rubber), NBR rubber, SBR rubber, vulcanizing agents, vulcanization accelerator aids, plasticizers such as naphthenic oils, fillers such as calcium carbonate, oxidation A disk-shaped test piece (referred to as test piece C) made of a material containing an inhibitor and a dispersing agent such as stearic acid, NR rubber, SBR rubber, vulcanizing agent, vulcanization accelerator aid, naphthenic A disk-shaped test piece (referred to as test piece D) made of a material containing a plasticizer such as oil, a filler such as calcium carbonate, an antioxidant, an antiozonant, and a dispersing agent such as stearic acid. were made with the same dimensions (diameter: 54.5 mm, thickness: 20 mm). Then, as shown in FIG. 4, the outer peripheral surfaces of the test pieces C and D were pressed against a wear disc 9 with a diameter of about 350 mm rotating at 60 rpm to observe the state of wear. Here, one end 91 is fixed about 300 mm above the center of the wear disc 9, and the other end 92 is attached with a weight 93 of 1 kg. C and D were attached and their outer peripheries were pressed against the wear disc 9 . Then, for each of the test pieces C and D, the wear volume after 600 rotations of the wear disc 9 was calculated from the wear weight (difference between the weight before the test and the weight after the test (after 600 revolutions of the wear disc)) and the specific gravity. Calculated. As a result, the wear volume of test piece D was about 5.5 ^cm3 , while the wear volume of test piece C was about 3.7 ^cm3 . It was confirmed that the abrasion resistance was improved by about 1.5 times compared to the test piece D in which EP rubber and NBR rubber were not blended.

An embodiment of the present invention has been described above.

In the cabtyre cable 1 according to the present embodiment, the sheath 3 is made of a blend rubber containing NR rubber and EP rubber, which has better weather resistance than the NR rubber. The weather resistance of the sheath 3 can be improved without adding an antiozonant to the NR rubber. Therefore, according to the present embodiment, it is possible to provide cabtyre cable 1 with excellent weather resistance without using an antiozonant.

In addition, in the present embodiment, by compounding NBR rubber into the blend rubber used as the material of the sheath 3, the NBR rubber functions as a binder between the NR rubber and the EP rubber contained in the blend rubber, The compatibility between the NR rubber and the EP rubber is improved, thereby reducing the variation in the quality of the sheath 3 and improving the manufacturing quality of the cabtire cable 1. - 特許庁

Further, in the present embodiment, the abrasion resistance of cabtyre cable 1 can be improved by blending NBR rubber and SBR rubber into the blend rubber used as the material of sheath 3 .

By the way, in a cabtyre cable, when current flows through the core conductor, the conductor generates heat due to its own electrical resistance. Since the amount of heat generated is determined by the value of the current flowing through the conductor, the insulator of the wire core is required to have heat resistance to withstand the temperature rise caused by the amount of heat generated depending on the value of the current flowing through the conductor. A conventional cabtire cable using NR rubber for the insulator of the wire core (for example, Patent Document 1) satisfies the required heat resistance by increasing the thickness of the insulator. Because cabtyre cables are required to have high heat resistance, the core insulation becomes thicker, resulting in an increase in the diameter and weight of the cabtyre cable, as well as a decrease in the flexibility of the cabtyre cable. It becomes difficult to handle the tire cable.

A highly heat-resistant cabtyre cable has been proposed in which EP rubber, which is more heat-resistant than NR rubber, is used as a core insulator, but EP rubber is inferior to NR rubber in pressure resistance. Therefore, even in a cabtyre cable using EP rubber for the wire core insulator, the wire core insulator must eventually be thickened in order to ensure pressure resistance. This increases the outer diameter and weight of the cabtyre cable and reduces the flexibility of the cabtyre cable, making it difficult to handle the cabtyre cable.

On the other hand, in the cabtyre cable 1 according to the present embodiment, the insulator 5 of the wire core 2 is made of EP rubber containing talc as a filler. As mentioned above, EP rubber is superior in heat resistance to NR rubber. In addition, talc is a layered mineral containing magnesium as a main component. By blending talc with EP rubber as a filler, it accumulates in the EP rubber and increases the dimensional stability in the talc deposition direction, that is, in the thickness direction of the EP rubber. is improved, and the withstand voltage of the insulator 5 is improved. Therefore, since it is not necessary to increase the thickness of the insulator 5 in order to ensure both heat resistance and pressure resistance, it is possible to prevent an increase in the outer diameter and weight of the cabtyre cable 1 and a decrease in flexibility. As a result, it is possible to provide the cabtyre cable 1 which is excellent in weather resistance, heat resistance and pressure resistance, and which is easy to handle.

Further, in the present embodiment, by using EP rubber vulcanized with peroxide for the insulator 5 of the wire core 2, the heat resistance of the cabtyre cable 1 can be further improved.

As described above, EP rubber has lower pressure resistance than NR rubber. Therefore, if EP rubber is blended into the material of the sheath 3 and the amount of NR rubber is reduced by that amount, the strength of the sheath 3 will decrease. This can be prevented by reducing the amount of the NR rubber and suppressing the amount of decrease in the NR rubber.

In the cabtyre cable 1 according to the above embodiment, the insulator 5 is omitted from the wire core 2, and the wire core 2 is replaced by the conductor 4 and the separator 6 that separates the conductor 4 from the sheath 3. may be configured. The cabtyre cable 1 in which the wire core 2 is composed of the conductor 4 and the separator 6 can be used, for example, as a cabtyre cable for a welding machine.

1: Cabtire cable 2: Wire core 3: Sheath 4: Conductor 5: Insulator 6: Separator 7: Test object 8: Horizontal table 9: Wear disc 70: Tip of test object 7 90: Arm 91, 92: End of arm 90 93: Weight

Claims (1)

A cabtyre cable manufacturing method comprising at least one wire core and a sheath made of a blended rubber covering the wire core,
The sheath is formed by mixing natural rubber, a carbon masterbatch of ethylene propylene rubber and nitrile rubber, a carbon masterbatch of styrene-butadiene rubber, a vulcanizing agent and a vulcanization accelerator in a mixer. A method for producing a cabtyre cable, comprising producing a blended rubber.

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