High temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material and manufacturing method thereof

Abstract

The present invention discloses a high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material and a manufacturing method thereof. The sheath material comprises: borosilicate rubber, low phenyl silicone rubber, methyl vinyl silicone rubber, phenylene ether silicone rubber, fumed silica, titanium dioxide, quartz powder, diatomaceous earth, diphenylsilanediol, hydroxy silicone oil, ferric oxide, nano mica powder, cerium oxide and dipentadienyl vulcanizer. The present invention has excellent acid resistance, chemical solvent resistance, radiation resistance and high flame retardant properties while having high temperature resistance, high strength and torsion resistance. In addition to being used in metallurgical industry cables to solve the problem of sheath carbonization in high temperature environments, it is also suitable for use in cable insulation and sheaths in extremely harsh environments such as aviation, chemical industry and atomic energy industry.

Description

Technical Field

[0001] The invention patent relates to a high temperature resistant, high strength, torsion resistant and highly flame retardant cable insulation sheath material and a manufacturing method thereof. Background Art

[0002] At present, the sheath of dynamic power cables for ramming cars, ladle cars, and slag tank cars in the domestic metallurgical industry generally adopts chloroprene rubber sheath or chlorinated polyethylene sheath. The conventional formula of chloroprene rubber sheath or chlorinated polyethylene sheath has an operating temperature of 90℃. Since the cable is in high-temperature radiation for a long time, the radiation temperature of the cable close to the smelting furnace reaches 300℃, and it is frequently dragged, curled and rotated. After 15 days to 3 months of use, the sheath will be carbonized and cracked when close to the high-temperature furnace and must be replaced. For the current atomic energy industry, the temperature resistance of the cable insulation sheath used is also low. Therefore, the problem of poor temperature resistance of cables in the metallurgical industry and the atomic energy industry is a problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention provides a high temperature resistant, high strength, torsion resistant and highly flame retardant cable insulation sheath material and a manufacturing method thereof. The material can enable the cable to have the characteristics of high temperature resistance, high strength, torsion resistance and high flame retardancy to meet the requirements for cable use in the metallurgical industry and the atomic energy industry.

[0004] The high-temperature resistant, high-strength, torsion-resistant and high-flame-retardant cable insulation sheath material of the present invention comprises the following raw materials in parts by weight: 50-90 parts of borosilicate rubber, 5-25 parts of low-phenyl silicone rubber, 5-25 parts of methyl vinyl silicone rubber, 2-10 parts of phenylene ether silicone rubber, 30-45 parts of fumed silica, 10-20 parts of titanium dioxide, 5-20 parts of quartz powder, 5-20 parts of diatomaceous earth, 2-5 parts of diphenylsilanediol, 2-5 parts of hydroxy silicone oil, 2-5 parts of ferric oxide, 5-10 parts of nano mica powder, 1-4 parts of cerium oxide and 0.5-2 parts of dipentadienyl vulcanizer.

[0005] The low phenyl silicone rubber preferably has a phenyl content of 6%-9%. The phenyl content refers to the molar percentage of phenyl segments in the silicone rubber molecule to the total number of segments, expressed as the ratio Ph (%) of the number of phenyl segments to the total number of polysiloxane molecular segments.

[0006] The methyl vinyl silicone rubber preferably has a molecular weight of 570,000-630,000 and a vinyl content of 0.13-0.17%. The vinyl content refers to the molar percentage of vinyl segments in the silicone rubber molecule to the total number of segments, expressed as the ratio Vi (%) of the number of segments containing vinyl to the total number of segments in the polysiloxane molecule.

[0007] In order to improve the tensile strength of the insulating sheath material and improve the heat resistance, the fumed silica comprises 40-45 parts, titanium dioxide 10-15 parts, quartz powder 10-20 parts, diatomaceous earth 10-15 parts, and nano-mica powder 5-8 parts.

[0008] The method for preparing the above-mentioned high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material comprises the following steps:

[0009] 1). Weigh half of the raw rubber by weight, which is borosilicate rubber + low phenyl silicone rubber + methyl vinyl silicone rubber, and put it into the internal mixer. At the same time, put one third of the formula by weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer, close the internal mixer and mix for 120-150 seconds;

[0010] 2). Open the internal mixer and add one-half of the formula weight of raw rubber (boron silicone rubber + low phenyl silicone rubber + methyl vinyl silicone rubber) into the internal mixer. At the same time, add one-third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer and mix for 120-150 seconds;

[0011] 3). Add one third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer, heat to 70±2℃ and mix for 120-150 seconds;

[0012] 4). After step 3) is completed, add diphenylsilanediol in the formula weight portion and heat to 70±2°C, mix and knead for 60-75 seconds;

[0013] 5). After step 4) is completed, add the hydroxy silicone oil in the formula weight and mix for 60-75 seconds;

[0014] 6). After step 5) is completed, add the phenyl ether silicone rubber in the formula weight parts and mix and knead for 60-75 seconds;

[0015] 7). After step 6) is completed, add the heat-resistant additive nano-mica powder, cerium oxide, and ferric oxide in the formula by weight and mix and knead for 120-150 seconds to obtain a mixed rubber compound;

[0016] 8). Filter the rubber. Put the mixed rubber into the rubber filter for filtering;

[0017] 9). The filter rubber obtained in step 8) is used to produce the sheet through the open mill;

[0018] 10). The film obtained in step 9) is subjected to aging treatment at room temperature.

[0019] 11). The aged film obtained in step 10) is passed through cooling water on the open mill for wrapping the roll;

[0020] 12). Weigh the dipentadienyl vulcanizing agent according to the formula, add it to the film obtained in step 11), and continue to roll it.

[0021] Preferably, the aging time in step 10) is more than 24 hours.

[0022] Preferably, in step 11), the roller spacing is adjusted to 8-10 mm and gradually reduced to 2-3 mm, and the rollers are wrapped on the open mill for 8-10 times. Step 12) The rollers are wrapped for 10 times.

[0023] Preferably, after step 12), the roller distance is gradually adjusted to 0.5-1 mm for thin pass until the film surface is smooth and free of bubbles.

[0024] Preferably, in step 8), three layers of metal filter screens are used for filtering the rubber, and the mesh numbers of the metal filter screens are 60, 80, and 100 respectively, and the temperature of the double rollers is 45-50°C during the wrapping process.

[0025] Beneficial effects of the present invention:

[0026] 1. The high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material of the present invention uses borosilicate rubber as the main rubber, low phenyl silicone rubber and methyl vinyl silicone rubber as the second and third auxiliary rubbers, and phenyl ether silicone rubber as the fourth reinforcing modified rubber. Combining the advantages of the four rubbers, the overall heat resistance of this formula reaches about 300-370°C and has excellent insulation performance, flame retardant performance and tensile strength.

[0027] 2. The high-temperature resistant, high-strength, torsion-resistant and high-flame-retardant cable insulation sheath material of the present invention adds 5-10 parts of nano-mica powder, 1-4 parts of cerium oxide, and 2-5 parts of ferric oxide to improve the heat resistance of the insulation sheath material, and cooperates with the borosilicate rubber + low-phenyl silicone rubber + methyl vinyl silicone rubber raw rubber system to increase the silicone rubber insulation sheath material from the normal working temperature of 180°C to 300-370°C.

[0028] 3. When the high-temperature-resistant, high-strength, torsion-resistant and high-flame-retardant cable insulation sheath material of the present invention is used as cable insulation, the long-term allowable working temperature of the conductor can reach 300°C, which is much higher than the long-term allowable working temperature of 180°C for silicone rubber film conductors used in conventional wires and cables, and the long-term allowable working temperature of 90°C for EPDM insulation film. The current carrying capacity of cables with the same cross-section is greatly improved. Under the same current carrying capacity, the required cable cross-section is smaller, which effectively reduces the cost and reduces the cable weight, making installation more convenient.

[0029] 4. The high temperature resistant, high strength, torsion resistant and high flame retardant cable insulation sheath material of the present invention adopts a di-25 vulcanizing agent with a high decomposition temperature. It is not easy to be pre-crosslinked in the screw when extruded by continuous vulcanization rubber extrusion equipment (length-to-diameter ratio: 12-16). Therefore, cable companies do not need to purchase special silicone rubber extruders and can use conventional continuous vulcanization rubber extrusion equipment (length-to-diameter ratio: 12-16) for production, thereby reducing fixed asset investment.

[0030] In summary, the high temperature resistant, high strength, torsion resistant and high flame retardant cable insulation sheath material of the present invention has high temperature resistance, high strength and torsion resistance, and at the same time has excellent acid resistance, chemical solvent resistance, radiation resistance and high flame retardancy. In addition to being used for cable insulation and sheathing in the metallurgical industry, it is also suitable for use in cable insulation and sheathing in extremely harsh environments such as aviation, chemical industry and atomic energy industry. DETAILED DESCRIPTION

[0031] Implementation Case 1: 90 parts of borosilicate rubber, 5 parts of low-phenyl silicone rubber, 5 parts of methyl vinyl silicone rubber, 10 parts of phenylene ether silicone rubber, 40 parts of fumed silica, 10 parts of titanium dioxide, 10 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 8 parts of nano-mica powder, 4 parts of cerium oxide, 1-1.5 parts of dipentadienyl vulcanizer

[0032] Implementation Case 2: 80 parts of borosilicate rubber, 10 parts of low-phenyl silicone rubber, 10 parts of methyl vinyl silicone rubber, 10 parts of phenylene ether silicone rubber, 40 parts of fumed silica, 10 parts of titanium dioxide, 10 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 7 parts of nano-mica powder, 3 parts of cerium oxide, 1-1.5 parts of dipentadienyl vulcanizer

[0033] Implementation Case 3:

[0034] 70 parts of borosilicate rubber, 15 parts of low-phenyl silicone rubber, 15 parts of methyl vinyl silicone rubber, 8 parts of phenylene ether silicone rubber, 45 parts of fumed silica, 10 parts of titanium dioxide, 20 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 8 parts of nano-mica powder, 3 parts of cerium oxide, and 1-1.5 parts of dipentadienyl vulcanizer.

[0035] Implementation Case 4: 60 parts of borosilicate rubber, 20 parts of low-phenyl silicone rubber, 20 parts of methyl vinyl silicone rubber, 7 parts of phenylene ether silicone rubber, 40 parts of fumed silica, 10 parts of titanium dioxide, 15 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 5 parts of nano-mica powder, 4 parts of cerium oxide, 1-1.5 parts of dipentadienyl vulcanizer

[0036] Implementation Case 5: 50 parts of borosilicate rubber, 25 parts of low-phenyl silicone rubber, 25 parts of methyl vinyl silicone rubber, 5 parts of phenylene ether silicone rubber, 35 parts of fumed silica, 10 parts of titanium dioxide, 15 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 7 parts of nano-mica powder, 4 parts of cerium oxide, and 1-1.5 parts of dipentadienyl vulcanizer.

[0037] Implementation Case 6: 50 parts of borosilicate rubber, 25 parts of low-phenyl silicone rubber, 25 parts of methyl vinyl silicone rubber, 5 parts of phenylene ether silicone rubber, 35 parts of fumed silica, 10 parts of titanium dioxide, 15 parts of quartz powder, 10 parts of diatomaceous earth, 2 parts of diphenylsilanediol, 2 parts of hydroxy silicone oil, 5 parts of ferric oxide, 3 parts of nano-mica powder, 2 parts of cerium oxide, and 1-1.5 parts of dipentadienyl vulcanizer.

[0038] For the formulations of the above 6 specific embodiments, the inventors used the following method to manufacture, and the steps are as follows:

[0039] Weigh one-half of the raw rubber (boron silicone rubber + low phenyl silicone rubber + methyl vinyl silicone rubber) by weight and put it into the internal mixer. At the same time, put one-third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer.

[0040] Close the charging door and mix borosilicate rubber, low phenyl silicone rubber, methyl vinyl silicone rubber, fumed silica, titanium dioxide, quartz powder and diatomaceous earth in the internal mixer for 120-150 seconds.

[0041] Open the internal mixer and add one-half of the formula weight of raw rubber (boron silicone rubber + low phenyl silicone rubber + methyl vinyl silicone rubber) into the internal mixer. At the same time, add one-third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer and mix for 120-150 seconds.

[0042] Add one third of the formula weight of fumed silica, titanium dioxide, quartz powder and diatomaceous earth into the internal mixer, raise the temperature to 70±2°C and mix for 120-150 seconds.

[0043] Add diphenylsilanediol in the formula weight portion, heat to 70±2°C and mix and knead for 60-75 seconds.

[0044] Add hydroxy silicone oil in the formula weight portion and mix and knead for 60-75 seconds.

[0045] Add phenylene ether silicone rubber in parts by weight of the formula and mix and knead for 60-75 seconds.

[0046] Add heat-resistant additive nano-mica powder, cerium oxide and ferric oxide in proportions by weight of the formula, and mix and knead for 120-150 seconds.

[0047] Filter the rubber. Put the mixed rubber into the rubber filter and start filtering. The head filter uses a three-layer metal filter with mesh numbers of 60, 80 and 100 respectively. The filter should be replaced every 300 kg. If the filter is suddenly damaged, the replacement should be stopped immediately. The rubber filtered out should be re-filtered. When changing the filter, the rubber 3mm away from the filter should be cut off and re-filtered.

[0048] Weigh 10 kg (per piece) of the sheet from the open mixer, roll it on the mixer and place it on the rack for more than 24 hours to ensure that all the ingredients are evenly dispersed.

[0049] 11. Sulfurization of the mixing mill

[0050] 11.1 Take out the film that has been stored for more than 24 hours in step 10. Start the open mill, open the cooling water valve, adjust the roller distance to 8-10mm and gradually reduce the roller distance to 2-3mm, and wrap the roller on the open mill 8-10 times.

[0051] 11.2 Accurately add dipentadienyl vulcanizer according to the formula and continue to roll it for 10 times.

[0052] 11.3 Gradually adjust the roller distance to 0.5-1mm and perform thin pass 5 times (the film surface should be smooth and free of bubbles. If it is not smooth, increase the number of thin passes), then adjust the roller distance to 6-8mm and place the film on the rack.

[0053] 11.4 During operation, the temperature of the double rollers is 45-50℃.

[0054] The inventor recorded the experimental data of the above experiments and compared them with the prior art, as shown in Table 1. From the data in Table 1, it can be seen that the present invention has the following advantages over the existing silicone rubber compound in the cable industry:

[0055] The tensile strength before aging is significantly increased by 40%-100%.

[0056] The heat resistance is significantly improved, so that the long-term allowable operating temperature of the silicone rubber film is increased from 180℃ to 300-370℃. The aging test temperature is increased from 200℃ to 370℃. The tensile strength and elongation at break of the implementation case 1 after aging at 370±2℃ for 10 days are similar to the data measured after aging at 200±2℃ for 10 days for the current silicone rubber compound.

[0057] The breakdown field strength is increased from 19-20kv / mm to 21-25kv / mm.

[0058] Table 1: Performance comparison of current silicone rubber insulation materials, silicone rubber sheath materials and implementation cases in the cable industry

[0059]

Claims

1. A high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material, comprising the following raw materials in parts by weight: 50-90 parts of borosilicate rubber, 5-25 parts of low phenyl silicone rubber, 5-25 parts of methyl vinyl silicone rubber, 2-10 parts of phenylene ether silicone rubber, 30-45 parts of fumed silica, 10-20 parts of titanium dioxide, 5-20 parts of quartz powder, 5-20 parts of diatomaceous earth, 2-5 parts of diphenylsilanediol, 2-5 parts of hydroxy silicone oil, 2-5 parts of ferric oxide, 5-10 parts of nano mica powder, 1-4 parts of cerium oxide, and 0.5-2 parts of dipentadienyl vulcanizing agent; The high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material has a heat resistance of 300-370°C; The phenyl content of the low-phenyl silicone rubber is 6%-9%, and the phenyl content refers to the molar percentage of the phenyl chain segments in the silicone rubber molecule to the total number of chain segments, expressed as the ratio Ph of the number of phenyl chain segments to the total number of polysiloxane molecule chain segments; The molecular weight of the methyl vinyl silicone rubber is 570,000-630,000, and the vinyl content is 0.13-0.17%. The vinyl content refers to the molar percentage of vinyl segments in the silicone rubber molecule to the total number of segments, expressed as the ratio Vi of the number of segments containing vinyl to the total number of segments in the polysiloxane molecule.

2. The high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 1 is characterized in that The fumed silica comprises 40-45 parts, titanium dioxide 10-15 parts, quartz powder 10-20 parts, diatomaceous earth 10-15 parts, and nano-mica powder 5-8 parts.

3. A method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 1 or 2, comprising the following steps: 1). Weigh half of the raw rubber by weight, which is borosilicate rubber + low phenyl silicone rubber + methyl vinyl silicone rubber, and put it into the internal mixer. At the same time, put one third of the formula by weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer, close the internal mixer and mix for 120-150 seconds; 2). Open the internal mixer and add one-half of the formula weight of raw rubber (boron silicone rubber + low phenyl silicone rubber + methyl vinyl silicone rubber) into the internal mixer again; at the same time, add one-third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer and mix for 120-150 seconds; 3). Add one third of the formula weight of fumed silica, titanium dioxide, quartz powder, and diatomaceous earth into the internal mixer, heat to 70±2℃ and mix for 120-150 seconds; 4). After step 3) is completed, add diphenylsilanediol in the formula weight portion and heat to 70±2°C, mix and knead for 60-75 seconds; 5). After step 4) is completed, add the hydroxy silicone oil in the formula weight and mix for 60-75 seconds; 6). Step 5) After completion, add the formula weight parts of phenyl ether support silicone rubber and mix for 60-75 seconds; 7). After step 6) is completed, add the heat-resistant additive nano-mica powder, cerium oxide, and ferric oxide in the formula by weight and mix and knead for 120-150 seconds to obtain a mixed rubber compound; 8). Filter the rubber. Put the mixed rubber into the rubber filter for filtering; 9). The filter rubber obtained in step 8) is passed through the open mill to produce the sheet; 10). The film obtained in step 9) is subjected to aging treatment at room temperature. 11). The aged film obtained in step 10) is passed through cooling water on the open mill for wrapping the roll; 12). Weigh the dipentadienyl vulcanizing agent according to the formula, add it to the film obtained in step 11), and continue to roll it.

4. The method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 3 is characterized in that The aging time in step 10) is more than 24 hours.

5. The method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 3, characterized in that Step 11) When wrapping the rolls, adjust the roll distance to 8-10 mm and gradually reduce the roll distance to 2-3 mm, and wrap the rolls on the mixing mill 8-10 times.

6. The method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 3, characterized in that Step 12) Continue wrapping the roller 10 times.

7. The method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 3, characterized in that Step 12) Then gradually adjust the roller distance to 0.5-1mm for thin pass until the film surface is smooth and free of bubbles.

8. The method for preparing the high temperature resistant, high strength, torsion resistant and flame retardant cable insulation sheath material according to claim 3, characterized in that Step 8) Use three layers of metal filter screens to filter the rubber, and the mesh numbers of each metal filter screen are 60, 80, and 100 respectively.

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