A heat-resistant silicon rubber cable for ladle car

Abstract

The application discloses a kind of silicon rubber cables for heat-resistant ladle car, belong to cable technical field.It includes wire core, insulating layer and sheath layer from inside to outside successively;Among them, the raw material of sheath layer includes the following components: by weight fraction, 80-100 parts of methyl vinyl silicone rubber, 10-12 parts of linear low density polyethylene, 4-5 parts of crosslinking agent, 10-12 parts of multifunctional additive, 1-2 parts of antioxidant and 1-2 parts of lubricant.The silicon rubber cable for heat-resistant ladle car provided in the application significantly improves the comprehensive performance of the cable after adding multifunctional additives in the sheath layer.

Description

Technical Field

[0001] This invention belongs to the field of cable technology, specifically relating to a heat-resistant silicone rubber cable for steel-clad vehicles. Background Technology

[0002] In high-temperature, dynamically moving industrial environments such as steel-clad trains, cables not only need to withstand continuous heat but also frequently experience bending, torsion, and mechanical impact. Therefore, stringent requirements are placed on the heat resistance, flexibility, flame retardancy, and long-term stability of the sheath material. Currently, traditional steel-clad train cables mostly use ordinary silicone rubber as the sheath material. While it possesses certain heat resistance and flexibility, its flame retardancy is poor, making it highly flammable under high temperatures or open flame conditions. Furthermore, combustion produces large amounts of dense smoke and toxic gases, posing significant safety hazards. To improve flame retardancy, a common practice is to add halogenated or phosphorus-based flame retardants to the silicone rubber matrix. However, these conventional flame retardants have poor compatibility with silicone rubber, easily leading to a decline in the material's mechanical properties, such as reduced tensile strength and decreased flexibility. This makes the sheath layer prone to cracking or fatigue failure under frequent movement and bending / torsion conditions. In addition, small-molecule flame retardants and additives are prone to migration, volatilization, or precipitation under long-term high-temperature and humid conditions, causing a decrease in flame retardant effect and accelerating the aging of the sheath material, significantly shortening the cable's service life.

[0003] Therefore, existing steel-clad automotive silicone rubber cables cannot achieve a good balance between flame retardancy efficiency, mechanical property retention, and long-term stability. There is an urgent need to develop a new type of cable sheath material that can simultaneously achieve high flame retardancy, high strength and toughness, heat aging resistance, and minimal additive migration. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a heat-resistant silicone rubber cable for steel ladle vehicles.

[0005] The objective of this invention can be achieved through the following technical solutions: A heat-resistant steel-clad vehicle silicone rubber cable comprises, from the inside out, a conductor, an insulation layer, and a sheath layer; wherein, the raw material of the sheath layer comprises the following components: by weight, 80-100 parts methyl vinyl silicone rubber, 10-12 parts linear low-density polyethylene, 4-5 parts crosslinking agent, 10-12 parts multifunctional additive, 1-2 parts antioxidant, and 1-2 parts lubricant.

[0006] In a more optimized manner, the preparation process of the multifunctional additive is as follows: A1: Mix acetyl-L-alanine, α-hydroxypropionic acid, and p-toluenesulfonic acid, stir until homogeneous, heat to 120℃, stir under normal pressure for 1-2 hours, then continue to heat to 150℃ and maintain the temperature for 6-7 hours. After the reaction is complete, stop heating, cool to 80℃, adjust pH to 5-6, distill under reduced pressure for 1-2 hours, and filter under reduced pressure while hot to obtain intermediate A. A2: Under a protective atmosphere, intermediate A was added to chloroform and stirred evenly at room temperature. Then, thionyl chloride was slowly added dropwise. After the addition was complete, the temperature was raised to 65°C and the mixture was refluxed for 4-5 hours. After the reaction was completed, the solvent and filtered thionyl chloride were removed by rotary evaporation to obtain intermediate B. A3: Dissolve 2,5-dihydroxyphenyl(diphenyl)phosphine oxide and triethylamine in chloroform and stir until homogeneous to obtain solution A; dissolve intermediate B in chloroform and stir until homogeneous to obtain solution B; under a protective atmosphere, slowly add solution B dropwise to solution A. After the addition is complete, raise the temperature to 70°C and reflux for 20-24 hours. After the reaction is complete, wash three times with deionized water to remove triethylamine hydrochloride and unreacted raw materials. Dry the organic phase with anhydrous magnesium sulfate, remove the solvent by rotary evaporation, and dry to obtain a multifunctional additive.

[0007] The structure of the multifunctional additive is shown below:

[0008] In a more optimized manner, the raw materials for preparing intermediate A include the following components: by weight, 130-140 parts of acetyl-L-alanine, 95-98 parts of α-hydroxypropionic acid, and 2-3 parts of p-toluenesulfonic acid.

[0009] In a more optimized manner, the raw materials for preparing intermediate B include the following components: by weight, 10-12 parts intermediate A, 50-60 parts chloroform, and 6-8 parts thionyl chloride.

[0010] In a more optimized manner, the raw materials for preparing solution A include the following components: by weight, 3-5 parts of 2,5-dihydroxyphenyl(diphenyl)phosphine oxide, 1-2 parts of triethylamine, and 80-100 parts of chloroform; the raw materials for preparing solution B include the following components: by weight, 4-5 parts of intermediate B and 60-80 parts of chloroform.

[0011] More preferably, the lubricant includes one or more of stearic acid and polyethylene wax.

[0012] More preferably, the antioxidant includes one or more of antioxidant 168 and antioxidant 2246.

[0013] The beneficial effects of this invention are: This invention provides a heat-resistant silicone rubber cable for steel-clad vehicles. The multifunctional additive introduced into its sheath layer, based on the molecular design principle of phosphorus-nitrogen synergistic flame retardancy and lactic acid ester flexible chain segments, can significantly improve the overall performance of the cable from multiple dimensions. Firstly, the additive molecule contains a phosphorus-phenanthroline ring structure and amide units. When the cable encounters high temperatures or open flames, phosphorus can catalyze carbonization in the condensed phase, forming a dense and stable carbon layer that effectively isolates oxygen and heat transfer. Simultaneously, nitrogen releases non-combustible gases in the gas phase to dilute oxygen and capture free radicals, synergistically achieving highly efficient flame retardancy and smoke suppression, significantly reducing smoke toxicity and emission levels, overcoming the shortcomings of traditional silicone rubber cables such as insufficient flame retardancy and the tendency to produce dense smoke during combustion. Secondly, the lactic acid ester prepolymer and flexible segments in the additive are well compatible with methyl vinyl silicone rubber and linear low-density polyethylene matrix, moderately weakening the secondary valence bonds between molecular chains, lowering the glass transition temperature of the sheath layer, and significantly improving the material's flexibility and processing fluidity. This allows the cable to maintain excellent fatigue resistance and mechanical stability under harsh conditions such as frequent movement, bending, and torsion in steel ladle cars, while avoiding the deterioration of the mechanical properties of silicone rubber by conventional flame retardants. Furthermore, this multifunctional additive has a high molecular weight and polar groups, exhibiting extremely low migration in the silicone rubber matrix. It is firmly bonded through chemical bonding or strong physical entanglement, significantly reducing the volatilization, precipitation, and migration of the additive, ensuring the sheath layer maintains stable performance under long-term high temperature, humid heat, and dynamic operating environments, thereby significantly extending the cable's service life. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1: The manufacturing process of a heat-resistant silicone rubber cable for steel-clad vehicles is as follows: Copper-tin alloy wires are twisted together to form a conductor to obtain the cable core. After being placed in parallel, styrene-butadiene rubber is extruded over the core to form an insulation layer. Then, an outer sheath material is extruded and coated on the surface of the insulation layer to form a sheath layer. The raw materials of the sheath layer include the following components: by weight, 80 parts methyl vinyl silicone rubber, 10 parts linear low-density polyethylene, 4 parts crosslinking agent, 10 parts multifunctional additive, 1 part antioxidant, and 1 part lubricant. The preparation process of the multifunctional additive is as follows: A1: Mix 130 parts of acetyl-L-alanine, 95 parts of α-hydroxypropionic acid, and 2 parts of p-toluenesulfonic acid, stir evenly, heat to 120℃, stir under normal pressure for 1 hour, then continue to heat to 150℃ and keep the reaction at this temperature for 6 hours. After the reaction is completed, stop heating, cool to 80℃, adjust the pH to 5 with dilute NaHCO3 solution, distill under reduced pressure for 1 hour, and filter under reduced pressure while hot to obtain intermediate A. A2: Under a protective atmosphere, 10 parts of intermediate A were added to 50 parts of chloroform and stirred evenly at room temperature. 6 parts of thionyl chloride were slowly added dropwise. After the addition was complete, the temperature was raised to 65°C and the reaction was carried out for 4 hours. After the reaction was completed, the solvent and excess thionyl chloride were removed by rotary evaporation to obtain intermediate B. A3: Dissolve 3 parts of 2,5-dihydroxyphenyl(diphenyl)phosphine oxide and 1 part of triethylamine in 80 parts of chloroform and stir until homogeneous to obtain solution A; dissolve 4 parts of intermediate B in 60 parts of chloroform and stir until homogeneous to obtain solution B; under a protective atmosphere, slowly add solution B dropwise to solution A. After the addition is complete, raise the temperature to 70°C and react for 20 hours. After the reaction is complete, wash three times with deionized water to remove triethylamine hydrochloride and unreacted raw materials. Dry the organic phase with anhydrous magnesium sulfate, remove the solvent by rotary evaporation, and dry to obtain a multifunctional additive.

[0016] Example 2: The manufacturing process of a heat-resistant silicone rubber cable for steel-clad vehicles is as follows: Copper-tin alloy wires are twisted together to form a conductor to obtain the cable core. After being placed in parallel, styrene-butadiene rubber is extruded over the core to form an insulation layer. Then, an outer sheath material is extruded and coated on the surface of the insulation layer to form a sheath layer. The raw materials of the sheath layer include the following components: by weight, 100 parts methyl vinyl silicone rubber, 12 parts linear low-density polyethylene, 5 parts crosslinking agent, 12 parts multifunctional additive, 2 parts antioxidant, and 2 parts lubricant. The preparation process of the multifunctional additive is as follows: A1: Mix 140 parts of acetyl-L-alanine, 98 parts of α-hydroxypropionic acid, and 3 parts of p-toluenesulfonic acid, stir evenly, heat to 120℃, stir under normal pressure for 2 hours, then continue to heat to 150℃ and keep the reaction at this temperature for 7 hours. After the reaction is completed, stop heating, cool to 80℃, adjust the pH to 6 with dilute NaHCO3 solution, distill under reduced pressure for 2 hours, and filter under reduced pressure while hot to obtain intermediate A. A2: Under a protective atmosphere, 12 parts of intermediate A were added to 60 parts of chloroform and stirred evenly at room temperature. 8 parts of thionyl chloride were slowly added dropwise. After the addition was complete, the temperature was raised to 65°C and the reaction was carried out for 5 hours. After the reaction was completed, the solvent and excess thionyl chloride were removed by rotary evaporation to obtain intermediate B. A3: Dissolve 5 parts of 2,5-dihydroxyphenyl(diphenyl)phosphine oxide and 2 parts of triethylamine in 100 parts of chloroform and stir until homogeneous to obtain solution A; dissolve 5 parts of intermediate B in 80 parts of chloroform and stir until homogeneous to obtain solution B; under a protective atmosphere, slowly add solution B dropwise to solution A. After the addition is complete, raise the temperature to 70°C and react for 24 hours. After the reaction is complete, wash three times with deionized water to remove triethylamine hydrochloride and unreacted raw materials. Dry the organic phase with anhydrous magnesium sulfate, remove the solvent by rotary evaporation, and dry to obtain a multifunctional additive.

[0017] Example 3: The manufacturing process of a heat-resistant silicone rubber cable for steel ladle vehicles is as follows: Copper-tin alloy wires are twisted together to form a conductor to obtain the cable core. After being placed in parallel, styrene-butadiene rubber is extruded over the core to form an insulation layer. Then, an outer sheath material is extruded and coated onto the surface of the insulation layer to form a sheath layer. The raw materials of the sheath layer include the following components: by weight, 90 parts methyl vinyl silicone rubber, 11 parts linear low-density polyethylene, 4.5 parts crosslinking agent, 11 parts multifunctional additive, 1.5 parts antioxidant, and 1.5 parts lubricant. The preparation process of the multifunctional additive is as follows: A1: Mix 135 parts of acetyl-L-alanine, 96.5 parts of α-hydroxypropionic acid, and 2.5 parts of p-toluenesulfonic acid, stir evenly, heat to 120℃, stir under normal pressure for 1.5h, then continue to heat to 150℃, keep the temperature for 6.5h, after the reaction is completed, stop heating, cool to 80℃, adjust pH to 5.5 with dilute NaHCO3 solution, distill under reduced pressure for 1.5h, filter under reduced pressure while hot to obtain intermediate A; A2: Under a protective atmosphere, 11 parts of intermediate A were added to 55 parts of chloroform and stirred evenly at room temperature. 7 parts of thionyl chloride were slowly added dropwise. After the addition was complete, the temperature was raised to 65°C and the reaction was carried out for 4.5 h. After the reaction was completed, the solvent and excess thionyl chloride were removed by rotary evaporation to obtain intermediate B. A3: Dissolve 4 parts of 2,5-dihydroxyphenyl(diphenyl)phosphine oxide and 1.5 parts of triethylamine in 90 parts of chloroform and stir until homogeneous to obtain solution A; dissolve 4.5 parts of intermediate B in 70 parts of chloroform and stir until homogeneous to obtain solution B; under a protective atmosphere, slowly add solution B dropwise to solution A. After the addition is complete, raise the temperature to 70°C and react for 22 hours. After the reaction is complete, wash three times with deionized water to remove triethylamine hydrochloride and unreacted raw materials. Dry the organic phase with anhydrous magnesium sulfate, remove the solvent by rotary evaporation, and dry to obtain a multifunctional additive.

[0018] Comparative Example 1: No multifunctional additives were added, as detailed below: Copper-tin alloy wires are twisted together to form a conductor to obtain the cable core. After being placed in parallel, styrene-butadiene rubber is extruded over the core to form an insulation layer. Then, an outer sheath material is extruded and coated on the surface of the insulation layer to form a sheath layer. The raw materials of the sheath layer include the following components: by weight, 90 parts methyl vinyl silicone rubber, 11 parts linear low-density polyethylene, 4.5 parts crosslinking agent, 1.5 parts antioxidant, and 1.5 parts lubricant.

[0019] Testing experiment: (1) The tensile strength of the cable sheath of the embodiments and comparative examples was tested in accordance with standard GB / T 1040.1-2025; (2) The oxygen index of the cable sheaths of the examples and comparative examples was determined by high temperature test according to standard GB / T 2406.3-2022; (3) The thermal properties of the sheath material were tested using a thermogravimetric analyzer. In the nitrogen range, the temperature was increased from room temperature to 800°C at a rate of 10°C / min. The test results are shown in the table below:

[0020] Conclusion: Based on the test results of the above embodiments and comparative examples, the addition of multifunctional additives to the sheath layer of the heat-resistant steel-clad silicone rubber cable provided by the present invention significantly improves the overall performance of the cable. Compared with the comparative example without multifunctional additives, the tensile strength of the sheath layer in Examples 1 to 3 is significantly improved, reaching 10.3 MPa, 11.2 MPa, and 11.8 MPa respectively, while the comparative example is only 6.5 MPa, indicating that the multifunctional additives can effectively improve the mechanical properties of the silicone rubber matrix. In terms of oxygen index, the examples all exceed 31%, reaching a maximum of 33.1%, which is much higher than the 25.6% of the comparative example, demonstrating excellent flame retardant performance. The initial decomposition temperature increases from 375.3℃ in the comparative example to over 430℃, reaching a maximum of 448.5℃, significantly enhancing thermal stability. The residual carbon content increases from 13.5% to 28.5%-33.1%, further confirming its flame retardant mechanism of forming a dense carbon layer at high temperatures. In summary, this heat-resistant silicone rubber cable for steel ladle vehicles achieves a synergistic improvement in high strength, high flame retardancy, high thermal stability, and long service life by introducing multifunctional additives, thus meeting the usage requirements of steel ladle vehicles and other high-temperature, dynamic, and harsh operating conditions.

[0021] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A heat-resistant silicone rubber cable for steel ladle vehicles, characterized in that, From the inside out, it includes a wire core, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components: by weight, 80-100 parts methyl vinyl silicone rubber, 10-12 parts linear low-density polyethylene, 4-5 parts crosslinking agent, 10-12 parts multifunctional additive, 1-2 parts antioxidant, and 1-2 parts lubricant.

2. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 1, characterized in that, The preparation process of the multifunctional additive is as follows: A1: Mix acetyl-L-alanine, α-hydroxypropionic acid, and p-toluenesulfonic acid, stir until homogeneous, heat to 120℃, stir under normal pressure for 1-2 hours, then continue to heat to 150℃ and maintain the temperature for 6-7 hours. After the reaction is complete, stop heating, cool to 80℃, adjust pH to 5-6, distill under reduced pressure for 1-2 hours, and filter under reduced pressure while hot to obtain intermediate A. A2: Under a protective atmosphere, intermediate A was added to chloroform and stirred evenly at room temperature. Then, thionyl chloride was slowly added dropwise. After the addition was complete, the temperature was raised to 65°C and refluxed for 4-5 hours. After the reaction was completed, the mixture was evaporated by rotary evaporation to obtain intermediate B. A3: Dissolve 2,5-dihydroxyphenyl(diphenyl)phosphine oxide and triethylamine in chloroform and stir until homogeneous to obtain solution A; dissolve intermediate B in chloroform and stir until homogeneous to obtain solution B; under a protective atmosphere, slowly add solution B dropwise to solution A. After the addition is complete, raise the temperature to 70°C and reflux for 20-24 hours. After the reaction is complete, wash three times with deionized water to remove triethylamine hydrochloride and unreacted raw materials. Dry the organic phase with anhydrous magnesium sulfate, remove the solvent by rotary evaporation, and dry to obtain a multifunctional additive.

3. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 2, characterized in that, The raw materials for preparing intermediate A include the following components: by weight, 130-140 parts acetyl-L-alanine, 95-98 parts α-hydroxypropionic acid, and 2-3 parts p-toluenesulfonic acid.

4. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 2, characterized in that, The raw materials for preparing intermediate B include the following components: by weight, 10-12 parts intermediate A, 50-60 parts chloroform, and 6-8 parts thionyl chloride.

5. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 2, characterized in that, The raw materials for preparing solution A include the following components: by weight, 3-5 parts of 2,5-dihydroxyphenyl(diphenyl)phosphine oxide, 1-2 parts of triethylamine, and 80-100 parts of chloroform; the raw materials for preparing solution B include the following components: by weight, 4-5 parts of intermediate B and 60-80 parts of chloroform.

6. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 1, characterized in that, The lubricant includes one or more of stearic acid and polyethylene wax.

7. The heat-resistant silicone rubber cable for steel ladle vehicles according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 168 and antioxidant 2246.

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