A high temperature resistant and corrosion resistant silicone rubber cable sheath material

Abstract

The application discloses a high-temperature-resistant and corrosion-resistant silicone rubber cable sheath material and belongs to the technical field of cable manufacturing. The material comprises the following raw materials in parts by weight: 75-85 parts of methyl vinyl silicone rubber, 25-35 parts of sericite powder, 5-8 parts of hydroxyl silicone oil, 1.5-3.5 parts of modified hydrogen-containing silicone oil, 0.05-0.2 parts of a catalyst, 0.05-0.3 parts of a vulcanization inhibitor, 0.3-1 parts of an antioxidant and 0.5-1.5 parts of a processing aid. The modified hydrogen-containing silicone oil is prepared by grafting an alkenyl amide product containing a naphthalene ring, a benzene ring and a trifluoromethyl sulfone group through a three-step reaction. The high-temperature-resistant and corrosion-resistant properties of the sheath material are remarkably improved through the synergistic effect of the sheet barrier effect of the sericite powder and the rigid aromatic structure, the sulfone group and the C-F bond in the modified hydrogen-containing silicone oil, and the sheath material is suitable for special cables in marine salt mist environments such as ships, offshore drilling platforms and offshore wind power facilities.

Description

Technical Field

[0001] This invention belongs to the field of cable manufacturing technology, specifically relating to a high-temperature and corrosion-resistant silicone rubber cable sheath material. Background Technology

[0002] In the cable manufacturing industry, the sheath material directly determines the cable's service life and operational reliability in complex environments. With the rapid development of marine resource development and the marine equipment manufacturing industry, the demand for special cables suitable for marine salt spray environments is increasing. Taking ships, offshore drilling platforms, and offshore wind power facilities as examples, their power and control cables are exposed to the typical "high temperature, high humidity, and high salt spray" marine atmospheric environment for extended periods. On the one hand, due to the concentrated operation of power equipment, the ambient temperature inside equipment compartments can be maintained between 80℃ and 150℃ for extended periods, and even higher in enclosed compartments or under poor heat dissipation conditions. On the other hand, seawater splashing and salt spray deposition cause a thin liquid film containing high concentrations of strong electrolytes such as sodium chloride and magnesium chloride to continuously adhere to the cable surface. Under alternating wet and dry conditions, the salt continuously concentrates and accumulates, forming a highly corrosive microenvironment. Under these harsh operating conditions with the coupling of these factors, the cable sheath material must simultaneously possess long-term high-temperature resistance and corrosion resistance. Defects in either aspect can lead to premature sheath failure, causing short circuits, leakage, or even fires, endangering equipment and personnel safety.

[0003] Silicone rubber, due to its unique silicon-oxygen bond backbone structure, possesses excellent high and low temperature resistance, good electrical insulation, ozone resistance, and weather resistance, making it widely used in the insulation and sheathing layers of special cables. However, in the high-temperature, high-salt, and high-humidity environment of marine salt spray, ordinary silicone rubber cable sheathing materials reveal serious performance shortcomings. First, when ordinary silicone rubber operates in a cabin environment exceeding 150°C for extended periods, the silicone rubber molecular chains are prone to thermo-oxidative degradation, leading to material hardening, decreased elasticity, and a gradual loss of its buffering and protective function for the internal conductor. More critically, the high concentration of chloride ions in the marine salt spray environment has a unique destructive mechanism on silicone rubber. Although silicone rubber itself has a hydrophobic surface, under long-term salt spray deposition and wet-dry cycles, chloride ions gradually penetrate and adsorb onto the silicone rubber surface, catalyzing the hydrolytic breakage of silicon-oxygen bonds. Furthermore, the unavoidable leakage of fuel oil, lubricating oil, and various chemical solvents in the marine environment can also cause swelling of ordinary silicone rubber. Ordinary silicone rubber has limited tolerance to non-polar or weakly polar oil media. Upon contact with diesel fuel, hydraulic oil, or cleaning agents, it easily expands in volume, reducing the seal between the sheath and the cable core, thus affecting electrical performance and mechanical protection. Therefore, there is an urgent need to develop a silicone rubber cable sheath material that combines high-temperature resistance and corrosion resistance to meet the high demands of marine salt spray environments. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature and corrosion-resistant silicone rubber cable sheath material.

[0005] The objective of this invention can be achieved through the following technical solutions: A high-temperature and corrosion-resistant silicone rubber cable sheath material comprises the following raw materials in parts by weight: 75-85 parts methyl vinyl silicone rubber (raw rubber), 25-35 parts sericite powder, 5-8 parts hydroxyl silicone oil, 1.5-3.5 parts modified hydrogen-containing silicone oil, 0.05-0.2 parts catalyst, 0.05-0.3 parts vulcanization inhibitor, 0.3-1 parts antioxidant, and 0.5-1.5 parts processing aid.

[0006] As a further technical solution, the modified hydrogen-containing silicone oil is prepared through the following steps: A1. In a dry round-bottom flask, 2,6-naphthalenedicarboxylic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl), 1-hydroxybenzotriazole (HOBt), and anhydrous N,N-dimethylformamide were added sequentially. Magnetic stirring was turned on, and N-methylmorpholine was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 20-30 min. Then, 3-aminophenyltrifluoromethyl sulfone was added, and the mixture was stirred at room temperature for 10-12 h. After the reaction was completed, the monoamide product was obtained after post-treatment. A2. In a dry round-bottom flask, add the monoamide product, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole and anhydrous N,N-dimethylformamide in sequence. Turn on the magnetic stirrer and add N-methylmorpholine dropwise. After the addition is complete, stir at room temperature for 20-30 min. Add 3-buten-1-amine and stir at room temperature for 8-10 h. After the reaction is complete, after post-treatment, the alkenylamide product is obtained. A3. In a dry three-necked flask, assemble a magnetic stirrer, a reflux condenser, a constant pressure dropping funnel, and a thermometer. Purge the air with nitrogen three times. Add hydrogen-containing silicone oil, alkenyl amide product, isopropanol, and toluene to the flask. After stirring evenly at room temperature, heat to 80-85℃. After the temperature stabilizes, add the catalyst and keep the reaction at this temperature for 4-5 hours. Once the reaction is complete, after post-treatment, the modified hydrogen-containing silicone oil is obtained.

[0007] As a further technical solution, the ratio of 2,6-naphthalenedicarboxylic acid and 3-aminophenyltrifluoromethyl sulfone in step A1 is 23.3-25.6g:22.5g.

[0008] As a further technical solution, the ratio of the amount of monoamide product to 3-buten-1-amine in step A2 is 42.3g:7.9-8.3g.

[0009] As a further technical solution, the ratio of the amount of hydrogen-containing silicone oil and alkenylamide product used in step A3 is 20g:3.5-4.1g.

[0010] In the process of preparing modified hydrogen-containing silicone oil, to ensure the successful acquisition of the modified hydrogen-containing silicone oil with the following chemical formula, it is necessary to note that in step A1, the molar ratio of 3-aminophenyltrifluoromethyl sulfone and 2,6-naphthalenedicarboxylic acid should be controlled to be close to 1:1, and 2,6-naphthalenedicarboxylic acid should be in excess, reserving one carboxyl group for the reaction in step A2. Moreover, in order to obtain modified hydrogen-containing silicone oil with low grafting rate (retaining most of Si-H), a small amount of alkenylamide product should be added in step A3.

[0011]

[0012] The modified hydrogen-containing silicone oil obtained by this invention has the following performance characteristics: First, the grafted benzene and naphthalene rings are both rigid aromatic structures with high thermal decomposition temperatures and conjugation stabilization effects. As rigid side groups in the silicone rubber crosslinking network, they effectively suppress the thermal motion of the siloxane backbone at high temperatures, delaying thermo-oxidative degradation and thus improving the long-term heat aging resistance of the sheath (especially suitable for cabin environments above 150°C).

[0013] Secondly, the sulfone group in the trifluoromethyl sulfone group exhibits extremely high thermal stability and a strong electron-withdrawing inductive effect. On the one hand, the sulfone group itself has a high thermal decomposition temperature and can stabilize adjacent aromatic rings through the electron-withdrawing effect, synergistically enhancing the overall high-temperature resistance. On the other hand, the sulfone group has good resistance to acid, alkali, and salt solutions (especially high concentrations of chloride ions in marine environments), preventing chloride ions from catalyzing the hydrolysis and breakage of silicon-oxygen bonds, thus significantly improving corrosion resistance.

[0014] Furthermore, the CF bond in the trifluoromethyl group is key to giving the material its superior hydrophobicity, oleophobicity, and chemical inertness. The extremely high bond energy and extremely low surface energy of the CF bond make it difficult for seawater, salt spray, and solvents such as fuel oil and lubricating oil to wet and penetrate the sheath surface, thereby significantly reducing the risk of swelling and corrosion damage.

[0015] Finally, grafting these functional groups onto hydrogen-containing silicone oil via chemical bonds offers significant additional advantages compared to simple physical blending. Firstly, the functional groups are anchored to the main chain of the hydrogen-containing silicone oil, and the silicone oil itself crosslinks into the three-dimensional network of the silicone rubber through hydrosilylation, thus preventing small molecule migration, precipitation (blooming), or volatilization, resulting in a long-lasting and stable modification effect. Secondly, the grafted rigid aromatic rings, located between crosslinking points, provide molecular-level reinforcement, improving the modulus and mechanical strength of the crosslinked network. Thirdly, the patent explicitly employs a low grafting rate design (retaining most of the Si-H groups), meaning that a small number of functional groups can significantly improve heat and corrosion resistance while preserving sufficient crosslinking active sites to ensure normal vulcanization of the silicone rubber and avoid excessive grafting leading to brittle materials or uncontrolled crosslinking.

[0016] As a further technical solution, the antioxidant is a phenolic antioxidant.

[0017] As a further technical solution, the catalyst is a platinum catalyst.

[0018] As a further technical solution, the processing aid is one of oleamide, calcium stearate, and zinc stearate.

[0019] The beneficial effects of this invention are: 1. The raw materials of this invention contain sericite powder, whose layered stacked structure forms a labyrinthine barrier layer in the matrix, effectively blocking the penetration of corrosive media such as chloride ions and sodium ions; at the same time, sericite has excellent high temperature resistance, which can improve the high temperature structural stability of the material and inhibit the degradation of molecular chains at high temperatures. 2. This invention modifies hydrogen-containing silicone oil, while retaining its crosslinking activity and introducing a variety of functional groups, which greatly improves the material's high temperature resistance, corrosion resistance and certain mechanical properties, and does not cause small molecule migration, precipitation (blooming) or volatilization, and its performance is stable over long-term use.

[0020] In summary, the sheath material obtained by this invention has both high temperature resistance and corrosion resistance, and has important application value in the field of marine engineering. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 Preparation of modified hydrogen-containing silicone oil: A1. In a dry round-bottom flask, add 34.9 g of 2,6-naphthalenedicarboxylic acid, 34.3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 24.3 g of 1-hydroxybenzotriazole, and 200 mL of anhydrous N,N-dimethylformamide in sequence. Turn on the magnetic stirrer and add 36.3 g of N-methylmorpholine dropwise. After the addition is complete, stir at room temperature for 20 min. Add 33.7 g of 3-aminophenyltrifluoromethyl sulfone and stir the reaction at room temperature for 10-12 h. After the reaction is complete, remove the solvent under reduced pressure to obtain the crude product. The crude product is purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:2 → 1:1) to obtain the monoamide product. A2. In a dry round-bottom flask, 42.3 g of the monoamide product, 23.1 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 16.0 g of 1-hydroxybenzotriazole, and 200 mL of anhydrous N,N-dimethylformamide were added sequentially. Magnetic stirring was started, and 23.8 g of N-methylmorpholine was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 20 min. Then, 7.9 g of 3-buten-1-amine was added, and the mixture was stirred at room temperature for 8 h. After the reaction was complete, the reaction solution was washed sequentially with saturated NaHCO3 solution and saturated brine, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:2 → 2:1) to obtain the alkenylamide product. A3. In a dry three-necked flask, assemble a magnetic stirrer, a reflux condenser, a constant pressure dropping funnel, and a thermometer. Purge the air with nitrogen three times. Add 20g of hydrogen-containing silicone oil (0.5% PHMS, where the mass fraction of H is 0.5%), 3.5g of alkenylamide product, 40mL of isopropanol, and 20mL of toluene to the flask. After stirring evenly at room temperature, heat to 80℃. After the temperature stabilizes, add 0.3mL of chloroplatinic acid catalyst (2% isopropanol solution). Keep the reaction at this temperature for 4 hours. After the reaction is complete, cool to room temperature and evaporate under reduced pressure to obtain modified hydrogen-containing silicone oil.

[0023] A high-temperature and corrosion-resistant silicone rubber cable sheath material is prepared through the following steps: 75 parts of methyl vinyl silicone rubber were added to a mixer (preheated to 50-60℃) and mixed for 2 minutes to soften the raw rubber and initially coat the rotor. 5 parts of hydroxyl silicone oil and 1.5 parts of modified hydrogen-containing silicone oil were added and mixed for another 3 minutes. Then, 25 parts of sericite powder, 0.3 parts of antioxidant 1010 and 0.5 parts of oleic acid amide were added in two batches and mixed for another 10 minutes until the powder was completely dispersed and the rubber compound was uniform in color. After mixing, the rubber compound was discharged from the mixer and immediately transferred to a two-roll mill (preheated to 70℃). 0.05 parts of caster catalyst and 0.05 parts of ethynylcyclohexanol (vulcanization inhibitor) were added, and the mixture was passed through a thin mill three times to obtain a high-temperature and corrosion-resistant silicone rubber cable sheath material.

[0024] Example 2 Preparation of modified hydrogen-containing silicone oil: A1. In a dry round-bottom flask, 38.3 g of 2,6-naphthalenedicarboxylic acid, 34.3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 24.3 g of 1-hydroxybenzotriazole, and 200 mL of anhydrous N,N-dimethylformamide were added sequentially. Magnetic stirring was started, and 36.3 g of N-methylmorpholine was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 30 min. Then, 33.7 g of 3-aminophenyltrifluoromethyl sulfone was added, and the mixture was stirred at room temperature for 12 h. After the reaction was complete, the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:2 → 1:1) to obtain the monoamide product. A2. In a dry round-bottom flask, 42.3 g of the monoamide product, 23.1 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 16.0 g of 1-hydroxybenzotriazole, and 200 mL of anhydrous N,N-dimethylformamide were added sequentially. Magnetic stirring was started, and 23.8 g of N-methylmorpholine was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 30 min. Then, 8.3 g of 3-buten-1-amine was added, and the mixture was stirred at room temperature for 10 h. After the reaction was complete, the reaction solution was washed sequentially with saturated NaHCO3 solution and saturated brine, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:2 → 2:1) to obtain the alkenylamide product. A3. In a dry three-necked flask, assemble a magnetic stirrer, a reflux condenser, a constant pressure dropping funnel, and a thermometer. Purge the air with nitrogen three times. Add 20g of hydrogen-containing silicone oil (0.5% PHMS, where the mass fraction of H is 0.5%), 4.1g of alkenylamide product, 40mL of isopropanol, and 20mL of toluene to the flask. After stirring evenly at room temperature, heat to 85℃. After the temperature stabilizes, add 0.3mL of chloroplatinic acid catalyst (2% isopropanol solution). Keep the reaction at this temperature for 5 hours. After the reaction is complete, cool to room temperature and evaporate under reduced pressure to obtain modified hydrogen-containing silicone oil.

[0025] A high-temperature and corrosion-resistant silicone rubber cable sheath material is prepared through the following steps: 80 parts of methyl vinyl silicone rubber were added to a mixer (preheated to 60°C) and mixed for 2 minutes to soften the raw rubber and initially coat the rotor. 6.5 parts of hydroxyl silicone oil and 2.5 parts of modified hydrogen-containing silicone oil were added and mixed for another 3 minutes. Then, 25-35 parts of sericite powder, 0.6 parts of antioxidant 1010 and 1.0 parts of zinc stearate were added in two batches and mixed for another 10 minutes until the powder was completely dispersed and the rubber compound was uniform in color. After mixing, the rubber compound was discharged from the mixer and immediately transferred to an open mill (preheated to 70-80°C). 0.1 parts of caster catalyst and 0.22 parts of ethynylcyclohexanol (vulcanization inhibitor) were added and the mixture was passed through a thin mill 5 times to obtain a high-temperature and corrosion-resistant silicone rubber cable sheath material.

[0026] Example 3 The only difference between this embodiment and Embodiment Two is that, in this embodiment, a high-temperature and corrosion-resistant silicone rubber cable sheath material is prepared through the following steps: 85 parts of methyl vinyl silicone rubber were added to a mixer (preheated to 60°C) and mixed for 2 minutes to soften the raw rubber and initially coat the rotor. 8 parts of hydroxyl silicone oil and 3.5 parts of modified hydrogen-containing silicone oil were added, and mixing continued for 3 minutes. Then, 35 parts of sericite powder, 1 part of antioxidant 1010, and 1.5 parts of calcium stearate were added in two batches, and mixing continued for 10 minutes until the powder was completely dispersed and the rubber compound was uniform in color. After mixing, the rubber compound was discharged from the mixer and immediately transferred to a two-roll mill (preheated to 80°C). 0.2 parts of caster catalyst and 0.3 parts of ethynylcyclohexanol (vulcanization inhibitor) were added, and the mixture was passed through a thin mill 5 times to produce sheets, thus obtaining a high-temperature and corrosion-resistant silicone rubber cable sheath material.

[0027] Comparative Example 1 The only difference between this comparative example and Example 1 is that, in this comparative example, an equal amount of unmodified ordinary hydrogen-containing silicone oil was used to replace the modified hydrogen-containing silicone oil to obtain the sheath material.

[0028] Comparative Example 2 The only difference between this comparative example and Comparative Example 1 is that, in this comparative example, sericite powder is not added to obtain the sheath material.

[0029] Examples 1, 2, and 3, along with Comparative Examples 1 and 2, were vulcanized. The vulcanization process was as follows: The sheath material was added to a flat vulcanizing machine. After the first stage of vulcanization (vulcanization temperature 130℃; vulcanization pressure 10MPa; vulcanization time 15min), the mold was opened, the sample was removed, and allowed to cool naturally to room temperature. A second stage of vulcanization was then performed (stage heating, holding at 80℃ for 1 hour, 120℃ for 2 hours, and 150℃ for 4 hours) to complete the process. The vulcanized material was then used to prepare samples according to the testing standards for performance determination. The testing standards are as follows: Tensile strength was determined according to GB / T 528-2009 standard; The tensile strength retention rate after aging at 200℃ for 72 hours was determined according to GB / T 3512-2014 standard. The surface condition was observed after continuous spraying with neutral salt spray (NSS) for 500 hours, in accordance with GB / T 10125-2021 standard. The volume change rate after treatment at 100℃ for 72 hours was determined using IRM903 oil, in accordance with GB / T 1690-2010 standard. The measurement results are shown in Table 1: Table 1

[0030] As can be seen from the table above, the sheath material prepared by the embodiments of the present invention has better high temperature resistance and corrosion resistance than the comparative example. Therefore, the present invention has important application value in the field of marine engineering.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A high-temperature and corrosion-resistant silicone rubber cable sheath material, characterized in that, The raw materials include the following parts by weight: 75-85 parts methyl vinyl silicone rubber, 25-35 parts sericite powder, 5-8 parts hydroxyl silicone oil, 1.5-3.5 parts modified hydrogen-containing silicone oil, 0.05-0.2 parts catalyst, 0.05-0.3 parts vulcanization inhibitor, 0.3-1 parts antioxidant, and 0.5-1.5 parts processing aids.

2. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 1, characterized in that, The modified hydrogen-containing silicone oil is prepared by the following steps: A1. Add 2,6-naphthalenedicarboxylic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole and anhydrous N,N-dimethylformamide to a flask, start stirring, add N-methylmorpholine dropwise, after the addition is complete, stir at room temperature for 20-30 min, add 3-aminophenyltrifluoromethyl sulfone, stir at room temperature for 10-12 h, the reaction is complete, and the monoamide product is obtained; A2. Add the monoamide product, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole and anhydrous N,N-dimethylformamide to a flask, start stirring, add N-methylmorpholine dropwise, after the addition is complete, stir at room temperature for 20-30 min, add 3-buten-1-amine, stir at room temperature for 8-10 h, the reaction is complete, and the alkenylamide product is obtained; A3. Add hydrogen-containing silicone oil, alkenyl amide product, isopropanol and toluene to the flask, stir evenly at room temperature, heat to 80-85℃, add catalyst, and reflux for 4-5 hours. The reaction is complete, and modified hydrogen-containing silicone oil is obtained.

3. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 2, characterized in that, In step A1, the ratio of 2,6-naphthalenedicarboxylic acid to 3-aminophenyltrifluoromethyl sulfone is 23.3-25.6 g: 22.5 g.

4. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 2, characterized in that, In step A2, the ratio of the monoamide product to 3-buten-1-amine is 42.3 g: 7.9-8.3 g.

5. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 2, characterized in that, In step A3, the ratio of the amount of hydrogen-containing silicone oil to the alkenylamide product is 20g:3.5-4.1g.

6. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 1, characterized in that, The antioxidant is a phenolic antioxidant.

7. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 1, characterized in that, The catalyst is a platinum catalyst.

8. The high-temperature and corrosion-resistant silicone rubber cable sheath material according to claim 1, characterized in that, The processing aid is one of oleamide, calcium stearate, and zinc stearate.

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