Flame-retardant ceramic silicone rubber sheath material for low-voltage cable and preparation method of flame-retardant ceramic silicone rubber sheath material
By combining modified corrosion-resistant fillers and gradient repair materials, the problem of easy degradation of ceramicized silicone rubber in extreme pH environments was solved, achieving efficient self-healing and corrosion resistance, and improving the flame retardant and mechanical properties of the material.
Patent Information
- Application Number
- CN202511925194.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-02-27
AI Technical Summary
Ceramicized silicone rubber is prone to chemical degradation in extreme pH environments, leading to a decline in its physical and mechanical properties. It also lacks self-healing capabilities and cannot effectively resist the penetration of corrosive media.
The combination of modified corrosion-resistant filler and gradient repair material is adopted. The modified corrosion-resistant filler forms a protective film through polyphenols and collagen, while the gradient repair material uses vinyl silicone oil and alumina fiber to achieve self-repair, thereby enhancing the density and strength of the ceramic skeleton.
It improves the flame retardancy and self-healing ability of ceramicized silicone rubber, enhances the corrosion resistance and mechanical properties of the material, and extends its service life.
Smart Images
Figure CN121574565A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cable sheath materials technology, specifically to a flame-retardant ceramicized silicone rubber sheath material for low-voltage cables and its preparation method. Background Technology
[0002] Ceramicized silicone rubber is a polymer composite material that can be transformed into ceramic materials at high temperatures. It is mainly used in the manufacture of fire-resistant wires and cables. Compared with traditional magnesium oxide mineral-insulated cables and mica tape-wrapped fire-resistant cables, the fire-resistant cables made from it have better economic efficiency and innovation, providing a new, efficient, and safe option for fire protection.
[0003] In environments with high concentrations of strong acids (such as concentrated sulfuric acid and concentrated hydrochloric acid) or strong alkalis (such as concentrated sodium hydroxide solution), ceramicized silicone rubber may undergo chemical degradation, swelling, or structural damage at extreme pH values due to the organosilicon polymer chains that make up its matrix and some ceramicized fillers. This leads to a decrease in the physical and mechanical properties of the material and a loss of its protective function. Furthermore, ceramicized silicone rubber itself does not have self-healing capabilities and cannot restore its original state after being ablated.
[0004] Therefore, this invention designs a flame-retardant ceramicized silicone rubber sheath material for low-voltage cables and a preparation method to improve the above-mentioned problems. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a flame-retardant ceramicized silicone rubber sheath material for low-voltage cables and its preparation method.
[0006] A flame-retardant ceramicized silicone rubber sheath material for low-voltage cables, comprising, by weight percentage: Corrosion-resistant filler: 3~5%; Gradient-type repair material: 5-8%; Inhibitor: 0.1~0.5; Vulcanizing agent: 1~2%; Flame retardant: 10~15%; Ceramic filler: 15~25%; Methyl vinyl silicone rubber: Balance; The corrosion-resistant filler is composed of corrosion-resistant filler with a particle size <30μm, corrosion-resistant filler with a particle size of 30~80μm, and corrosion-resistant filler with a particle size of 80~200μm. The mass ratio of the corrosion-resistant filler with a particle size <30μm, the corrosion-resistant filler with a particle size of 30~80μm, and the corrosion-resistant filler with a particle size of 80~200μm is 3:5:1~2. The gradient repair material is prepared by sequentially pressing a second gradient repair material, a first gradient repair material, and a second gradient repair material in a mass ratio of 3:1:2~3.
[0007] Furthermore, the corrosion-resistant filler is a modified corrosion-resistant filler, and the preparation method of the modified corrosion-resistant filler is as follows: Polyphenols and collagen are dispersed in an ethanol solution with a concentration of 60-70 wt% at a solid-liquid ratio of 0.8:0.6 g:15-20 ml. The polyphenols are any one of EGCG, resveratrol, and gallic acid esters to obtain a mixed solution. Then, 1,3-diepoxybutane, accounting for 8-10 wt% of the polyphenols, is added to the mixed solution and reacted at 25-30°C for 2-3 hours to obtain a reaction solution. 4,4'-diaminodiphenylmethane, chitosan, and glutaraldehyde were reacted at 75-85℃ for 10-12 h in a mass ratio of 1:4-6:0.7 to obtain a modified chitosan solution. The reaction solution was added dropwise to the modified chitosan solution at a volume ratio of 1:1 to 2, and then subjected to microjet treatment. The microjet reactor had a single channel with a channel size of 100 to 150 μm; the pressure was 100 to 150 MPa; the injection was repeated 15 to 20 times; the injection rate was 50 to 100 mL / min; and the product was freeze-dried to obtain modified polyphenols. The modified polyphenols, nano silica, and silane coupling agent are then reacted at 70-75℃ for 2.5-3 hours according to the specified ratio to obtain the modified corrosion-resistant filler.
[0008] Explanation: When corrosive media penetrate, the catechol groups in the polyphenols are released, forming a protective film on the sheath surface to resist corrosion. Collagen cross-links with polyphenols to form a barrier that prevents the penetration of corrosive media such as water, oxygen, and chloride ions. The modified chitosan solution has better mechanical properties and can be used as a reinforcing component in silicone rubber. During the high-temperature ceramization process, this modified chitosan can be carbonized more effectively and participate in the construction of a robust ceramic skeleton, which helps to improve the density and strength of the ceramic body, thereby optimizing the flame retardant properties of the ceramized silicone rubber. Microjets promote a tighter bond between polyphenols, collagen, and modified chitosan, improving the long-term stability of the modified corrosion-resistant filler.
[0009] Furthermore, the corrosion-resistant filler is any one of kaolin, talc, or zinc borate.
[0010] Note: The above components can form a hard ceramic framework at high temperatures; they are chemically stable and provide basic corrosion resistance.
[0011] Furthermore, the preparation method of the gradient repair material is as follows: Vinyl silicone oil, rhodium dioxide, and silane coupling agent with a concentration of 70-80 wt% are mixed at a liquid-solid ratio of 10-20 ml: 0.1 g: 0.4 g at 60-70 °C for 1-2 h to obtain an inner layer repair solution. The inner layer repair solution, emulsifier, and water are then mixed at a ratio of 6 ml: 1 g: 10-12 ml to obtain an emulsion. The pH of the emulsion was adjusted to 8-9, and dopamine hydrochloride with a concentration of 1.5-2.5 mg / ml was added to the emulsion at a mass ratio of 8-9:1. The mixture was stirred at room temperature for 18-22 hours. After the reaction was completed, the mixture was centrifuged, and the centrifuged product was repeatedly washed with deionized water and freeze-dried to obtain the first-gradient repair material. Vinyl silicone oil, chloroplatinic acid, and ethynylcyclohexanol with a concentration of 40-50 wt% were mixed at a ratio of 8-10 ml: 0.01 g: 0.005 g for 1.5-2 h at 50-60 °C to obtain the outer layer repair solution. Alumina fiber body is impregnated in outer repair liquid at a solid-liquid ratio of 1g:5~8ml under a pressure of 0.8~1MPa and a temperature of 55~65℃. The impregnated product is then repeatedly washed with deionized water and heat-cured at 110~120℃ for 1.5~2h to obtain the second-gradient repair material. The second-gradient repair material, the first-gradient repair material, and the second-gradient repair material are laid in the mold in a certain proportion, and then hot-pressed at 120~130℃ for 1~2 minutes to obtain a gradient self-healing material.
[0012] Explanation: Vinyl silicone oil serves as both a carrier and a flexible matrix for the repair agent. When microcracks develop in the material, the silicone oil can flow and fill the cracks. Rhodium dioxide exhibits high activity and selectivity for reactions such as hydrosilylation, rapidly initiating cross-linking reactions at room temperature or lower, thus healing the cracks. The emulsion in a weakly alkaline environment undergoes oxidative self-polymerization with dopamine hydrochloride to form a polymer, creating a robust shell. When local pH changes due to corrosion, the polydopamine shell responds, controlling the release of the first-gradient repair material and also enhancing the bonding strength between the first-gradient repair material and the ceramicized silicone rubber matrix. In the second-gradient repair material… In the chloroplatinic acid / ethynylcyclohexanol system, when microcracks occur in the material, the fiber ruptures, prompting the internal repair material to fill and heal the cracks. Directional freezing of the alumina short fiber dispersion allows the fibers to form an ordered skeletal structure within the material, effectively hindering crack propagation and improving the material's fracture toughness and impact resistance. Furthermore, through gradient composites, the surface layer preferentially addresses larger cracks caused by mechanical damage, repairing them through rapid chemical cross-linking. The intermediate layer, utilizing its inherent self-healing properties, can handle more subtle damage or repairs triggered by humidity or pH changes, thus improving the repair success rate and the material's service life.
[0013] Further, the alumina fiber body is prepared by dispersing alumina short fibers in deionized water at a solid-liquid ratio of 1g:30~40ml to obtain a dispersion, and then directionally freezing it at -25~-35℃ for 10~12h to obtain the alumina fiber body.
[0014] Note: Directional freezing of alumina short fiber dispersion can cause the fibers to form an orderly skeletal structure inside the material, effectively hindering crack propagation and improving the fracture toughness and impact resistance of the material.
[0015] Furthermore, the vulcanizing agent is benzoyl peroxide.
[0016] Note: The free radicals generated after BPO decomposes upon heating can capture hydrogen atoms from the molecular chains of methyl vinyl silicone rubber, thereby initiating the formation of a strong carbon-carbon cross-linking network between the silicone rubber molecular chains, resulting in excellent thermal stability.
[0017] Furthermore, the inhibitor is 2-methyl-3-yn-2-ol.
[0018] Note: Alkyne alcohols can interact with the platinum catalyst in the repair material, temporarily inhibiting its catalytic activity, thereby effectively preventing premature vulcanization of the rubber compound in the processing equipment. This provides an important guarantee for obtaining a uniform compound.
[0019] Furthermore, the flame retardant is Lavaz 8685 flame retardant.
[0020] Note: The free radicals generated by the high-temperature decomposition of Lavaz 8685 flame retardant can capture the ·H and ·OH free radicals in the combustion chain reaction, thus interrupting the combustion reaction.
[0021] Furthermore, the ceramic filler is mica powder.
[0022] Note: When exposed to high temperatures or flames, mica powder can melt and participate in the formation of a continuous, hard ceramic protective layer.
[0023] A method for preparing a flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in any of the above claims includes the following steps: S1. First, mix the corrosion-resistant filler with a particle size <30μm, the gradient repair material, the flame retardant, the ceramic filler, and the methyl vinyl silicone rubber at 40~50rpm for 30~40min. Then, add the corrosion-resistant filler with a particle size of 30~80μm and mix at 80~100rpm for 25~30min. Finally, add the corrosion-resistant filler with a particle size of 80~200μm and mix at 110~120rpm for 15~20min to obtain the mixture. The relationship between the mixing temperature T of each mixing step, the average particle size R of the corresponding added corrosion-resistant filler, and the mass ratio m of the corresponding added corrosion-resistant filler to the total corrosion-resistant filler is as follows: T = |50-R| / m; S3. Add inhibitors to the mixture in proportion and mix at 100~120℃ for 15~20min; S4. Add vulcanizing agent according to the ratio, and vulcanize at 180~190℃ and 8~10MPa for 5~10 minutes to obtain ceramic flame-retardant silicone rubber.
[0024] Compared with existing ceramicized silicone rubber sheath materials, the beneficial effects of this invention are: (1) In the modified corrosion-resistant filler of the sheath material of the present invention, when corrosive media invade, the catechol groups in the polyphenols are released to form a protective film on the surface of the sheath to resist corrosion. Collagen and polyphenol crosslink to form a barrier that blocks the penetration of corrosive media such as water, oxygen, and chloride ions. The modified chitosan solution has better mechanical properties and can be used as a reinforcing component in silicone rubber. In the process of high-temperature ceramicization, this modified chitosan can be carbonized more effectively and participate in the construction of a strong ceramic skeleton, which helps to improve the density and strength of the ceramic body, thereby optimizing the flame retardant properties of ceramicized silicone rubber. Microjets promote the formation of a tighter bond between polyphenols-collagen and modified chitosan, improving the long-term stability of the modified corrosion-resistant filler.
[0025] (2) The gradient repair material designed in this invention uses vinyl silicone oil as the repair agent carrier and flexible matrix. When microcracks occur in the material, the silicone oil can flow and fill the cracks. Rhodium dioxide has high activity and selectivity for reactions such as hydrosilylation. When cracks occur, it can quickly initiate cross-linking reactions at room temperature or lower temperatures to achieve crack healing. The emulsion in a weakly alkaline environment is oxidized and self-polymerized with dopamine hydrochloride to form a polymer, forming a strong shell. When the local pH changes due to corrosion, the polydopamine shell responds to control the release of the first gradient repair material, which also helps to improve the bonding force between the first gradient repair material and the ceramicized silicone rubber matrix; the second In the gradient repair material, the chloroplatinic acid / ethynylcyclohexanol system causes fiber rupture when microcracks occur, prompting the internal repair material to fill and heal the cracks. Directional freezing of the alumina short fiber dispersion allows the fibers to form an ordered skeletal structure within the material, effectively hindering crack propagation and improving the material's fracture toughness and impact resistance. Furthermore, through gradient composite processing, the surface layer preferentially addresses larger cracks caused by mechanical damage, repairing them through rapid chemical cross-linking. The intermediate layer, utilizing its inherent self-healing properties, can handle more subtle damage or repairs triggered by humidity or pH changes, thus improving the repair success rate and the material's lifespan.
[0026] (3) In this invention, the modified corrosion-resistant filler is ground into particles of different sizes and then filled with each other. This can significantly reduce the voids between fillers and the interface defects between fillers and silicone rubber matrix, improve the compactness of the sheath material, and mix small-particle fillers and other components at a lower speed. This is beneficial for nanoscale fillers and ceramic fillers to achieve initial and uniform dispersion in a high-viscosity matrix, laying a homogeneous foundation for the entire system. Then, the speed is gradually increased to add fillers with larger particle sizes. The enhanced shear force is used to overcome the agglomeration potential energy between particles, ensuring that each level of filler can be fully dispersed. This avoids local stress concentration points caused by filler agglomeration, thereby improving the overall uniformity and mechanical reliability of the material. The mixing temperature is adjusted according to the particle size of the added filler, which helps to match the most suitable processing viscosity and interfacial force for fillers of different sizes, optimize the dispersion state of fillers in the matrix, and reduce material degradation caused by local overheating. Attached Figure Description
[0027] Figure 1 This is a comparison chart of the loss results in Experiment Example 1 of the Sheath Material of the present invention; Figure 2 This is a comparison chart of the self-healing rate results of Experimental Example 1 of the Sheath Material of the present invention; Figure 3 This is a comparison chart of the self-healing rate results of Experimental Example 2 of the Sheath Material of the present invention; Figure 4 This is a comparison chart of the loss results in Experiment Example 3 of the Sheath Material of the present invention; Figure 5 This is a comparison chart of the loss results in Experiment Example 4 of the Sheath Material of the present invention; Figure 6 This is a comparison chart of the self-healing rate results of Experimental Example 4 of the Sheath Material of the present invention. Detailed Implementation
[0028] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.
[0029] Example 1: A flame-retardant ceramicized silicone rubber sheath material for low-voltage cables, comprising, by weight percentage: Corrosion-resistant filler (kaolin): 4%; Gradient-type repair material: 7%; Inhibitor (2-methyl-3-yn-2-ol): 0.3%; Vulcanizing agent (benzoyl peroxide): 1.5%; Lavaz 8685 flame retardant: 12%; Ceramic filler (mica powder): 20%; Methyl vinyl silicone rubber: Balance; The corrosion-resistant filler is composed of corrosion-resistant fillers with a particle size <30μm, corrosion-resistant fillers with a particle size of 30~80μm, and corrosion-resistant fillers with a particle size of 80~200μm, wherein the mass ratio of the corrosion-resistant fillers with a particle size <30μm, the corrosion-resistant fillers with a particle size of 30~80μm, and the corrosion-resistant fillers with a particle size of 80~200μm is 3:5:1.5; The gradient repair material is formed by sequentially pressing a second gradient repair material, a first gradient repair material, and a second gradient repair material in a mass ratio of 3:1:2.5. The preparation method of the gradient repair material is as follows: Vinyl silicone oil (75 wt%), rhodium dioxide, and KH-560 silane coupling agent were mixed at 65°C for 1.5 h with a liquid-to-solid ratio of 15 ml: 0.1 g: 0.4 g to obtain an inner layer repair solution. The inner layer repair solution, emulsifier (sodium dodecyl sulfate), and water were then mixed at a solid-to-liquid ratio of 6 ml: 1 g: 11 ml to obtain an emulsion. The pH of the emulsion was adjusted to 8.5, and dopamine hydrochloride with a concentration of 2 mg / ml was added to the emulsion at a mass ratio of 8.5:1. The mixture was stirred at room temperature for 20 h. After the reaction was completed, the mixture was centrifuged at 3500 rpm for 2 min. The centrifuged product was repeatedly washed with deionized water and freeze-dried at -50℃ for 20 h to obtain the first gradient repair material. Vinyl silicone oil (45 wt%), chloroplatinic acid, and ethynylcyclohexanol were mixed at 55°C for 1.8 h in a mass ratio of 9 ml: 0.01 g: 0.005 g to obtain the outer layer repair solution. Short alumina fibers were dispersed in deionized water at a solid-liquid ratio of 1g:35ml to obtain a dispersion, which was then directionally frozen at -30℃ for 11h to obtain alumina fiber body. Alumina fiber was impregnated in the outer repair solution at a solid-liquid ratio of 1g:6ml under a pressure of 0.9MPa and a temperature of 60℃. The impregnated product was then repeatedly washed with deionized water and heat-cured at 115℃ for 1.9h to obtain the second-gradient repair material. The second-gradient repair material, the first-gradient repair material, and the second-gradient repair material are laid in the mold in a certain proportion, and then hot-pressed at 125℃ for 1.5 minutes to obtain the gradient self-healing material.
[0030] Example 2: A method for preparing flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in Example 1, comprising the following steps: S1. First, mix the corrosion-resistant filler with a particle size <30μm, the gradient repair material, the flame retardant, the ceramic filler, and the methyl vinyl silicone rubber at 45rpm for 35min. Then, add the corrosion-resistant filler with a particle size of 30~80μm and mix at 90rpm for 28min. Finally, add the corrosion-resistant filler with a particle size of 80~200μm and mix at 115rpm for 18min to obtain the compound. The relationship between the mixing temperature T of each mixing step, the average particle size R of the corresponding added corrosion-resistant filler (which can be understood as the average particle size R corresponding to particle sizes of 15μm, 55μm, and 140μm in S1), and the mass ratio m of the corresponding added corrosion-resistant filler to the total corrosion-resistant filler is as follows (which can be understood as the following formula representing a numerical relationship, i.e., T on the left side is taken from the value calculated on the right side): T = |50-R| / m; S2. Add inhibitor to the mixture in proportion and mix at 110°C for 18 minutes. S3. Add vulcanizing agent according to the ratio, and vulcanize at 185℃ and 9MPa for 8 minutes to obtain ceramic flame-retardant silicone rubber.
[0031] Example 3: This example differs from Example 1 in that the sheath material, by mass percentage, comprises: Corrosion-resistant filler (talc): 3%; the mass ratio of corrosion-resistant filler with particle size <30μm, corrosion-resistant filler with particle size 30~80μm, and corrosion-resistant filler with particle size 80~200μm is 3:5:1; Gradient repair material: 5%; The gradient repair material is made by sequentially pressing a second gradient repair material, a first gradient repair material, and a second gradient repair material in a mass ratio of 3:1:2; Inhibitor (2-methyl-3-yn-2-ol): 0.1; Vulcanizing agent (benzoyl peroxide): 1%; Lavaz 8685 flame retardant: 10%; Ceramic filler (mica powder): 15%; Methyl vinyl silicone rubber: Balance.
[0032] Example 4: This example differs from Example 1 in that the sheath material, by mass percentage, comprises: Corrosion-resistant filler (zinc borate): 5%; the mass ratio of corrosion-resistant filler with particle size <30μm, corrosion-resistant filler with particle size 30~80μm, and corrosion-resistant filler with particle size 80~200μm is 3:5:2; Gradient repair material: 8%; The gradient repair material is made by sequentially pressing a second gradient repair material, a first gradient repair material, and a second gradient repair material in a mass ratio of 3:1:3; Inhibitor (2-methyl-3-yn-2-ol): 0.5; Vulcanizing agent (benzoyl peroxide): 2%; Lavaz 8685 flame retardant: 15%; Ceramic filler (mica powder): 25%; Methyl vinyl silicone rubber: Balance.
[0033] Example 5: This example differs from Example 1 in that a 70wt% vinyl silicone oil, rhodium dioxide, and coupling agent are mixed at 60°C for 1 hour with a liquid-solid ratio of 10ml:0.1g:0.4g to obtain an inner layer repair solution.
[0034] Example 6: The difference between this example and Example 1 is that 80wt% vinyl silicone oil, rhodium dioxide and coupling agent are mixed at 70°C for 2 hours with a liquid-solid ratio of 20ml:0.1g:0.4g to obtain the inner layer repair solution.
[0035] Example 7: This example differs from Example 1 in that the inner layer repair solution, emulsifier, and water are mixed in a solid-liquid ratio of 6ml:1g:10ml to obtain an emulsion; the pH of the emulsion is adjusted to 8, and then dopamine hydrochloride with a concentration of 1.5mg / ml is added to the emulsion in a mass ratio of 8:1, and the mixture is stirred at room temperature for 18 hours.
[0036] Example 8: This example differs from Example 1 in that the inner layer repair solution, emulsifier, and water are mixed in a solid-liquid ratio of 6ml:1g:12ml to obtain an emulsion; the pH of the emulsion is adjusted to 9, and then dopamine hydrochloride with a concentration of 2.5mg / ml is added to the emulsion in a mass ratio of 9:1, and the mixture is stirred at room temperature for 22h.
[0037] Example 9: This example differs from Example 1 in that vinyl silicone oil with a concentration of 40wt%, chloroplatinic acid, and ethynylcyclohexanol are mixed at 50°C for 1.5 hours in a mass ratio of 8ml:0.01g:0.005g to obtain an outer layer repair solution.
[0038] Example 10: This example differs from Example 1 in that vinyl silicone oil, chloroplatinic acid, and ethynylcyclohexanol with a concentration of 50wt% are mixed at 60°C for 2 hours in a mass ratio of 10ml:0.01g:0.005g to obtain an outer layer repair solution.
[0039] Example 11: The difference between this example and Example 1 is that alumina short fibers are dispersed in deionized water at a solid-liquid ratio of 1g:30ml to obtain a dispersion, which is then directionally frozen at -25℃ for 10h to obtain a fiber body.
[0040] Example 12: The difference between this example and Example 1 is that alumina short fibers are dispersed in deionized water at a solid-liquid ratio of 1g:40ml to obtain a dispersion, which is then directionally frozen at -35℃ for 12h to obtain a fiber body.
[0041] Example 13: The difference between this example and Example 1 is that the fiber body is impregnated in the outer repair liquid at a solid-liquid ratio of 1g:5ml under a pressure of 0.8MPa and a temperature of 55℃. The impregnated product is then repeatedly washed with deionized water and heat-cured at 110℃ for 1.5h to obtain the second gradient repair material.
[0042] Example 14: The difference between this example and Example 1 is that the fiber body is impregnated in the outer repair liquid at a solid-liquid ratio of 1g:8ml under a pressure of 1MPa and a temperature of 65℃. The impregnated product is then repeatedly washed with deionized water and heat-cured at 120℃ for 2 hours to obtain the second gradient repair material.
[0043] Example 15: The difference between this example and Example 1 is that the second gradient repair material, the first gradient repair material, and the second gradient repair material are laid in the mold in proportion, and then hot-pressed at 120°C for 1 minute to obtain a gradient self-healing material.
[0044] Example 16: The difference between this example and Example 1 is that the second gradient repair material, the first gradient repair material, and the second gradient repair material are laid in the mold in proportion, and then hot-pressed at 130°C for 2 minutes to obtain a gradient self-healing material.
[0045] Example 17: This example differs from Example 1 in that the corrosion-resistant filler is a modified corrosion-resistant filler, and the preparation method of the modified corrosion-resistant filler is as follows: Polyphenols (EGCG) and collagen were dispersed in a 65wt% ethanol solution at a solid-liquid ratio of 0.8:0.6g:18ml to obtain a mixed solution. Then, 1,3-diepoxybutane, accounting for 9wt% of the polyphenols, was added to the mixed solution and reacted at 28℃ for 2.5h to obtain a reaction solution. 4,4'-diaminodiphenylmethane, chitosan, and glutaraldehyde were reacted at 80°C for 11 h in a mass ratio of 1:5:0.7 to obtain a modified chitosan solution. The reaction solution was added dropwise to the modified chitosan solution at a volume ratio of 1:1.5 and subjected to microjet treatment. The microjet reactor had a single channel with a channel size of 120 μm; the pressure was 125 MPa; the injection was repeated 18 times at a rate of 80 mL / min; and the product was freeze-dried at -50 °C for 24 h to obtain modified polyphenols. The modified polyphenols, nano silica, and KH550 silane coupling agent were then reacted at 73°C for 2.8 hours according to the specified ratio to obtain the modified corrosion-resistant filler.
[0046] Example 18: This example differs from Example 17 in that polyphenols (resveratrol) and collagen are dispersed in a 60wt% ethanol solution at a solid-liquid ratio of 0.8:0.6g:15ml to obtain a mixed solution. Then, 1,3-diepoxybutane, accounting for 8wt% of the polyphenols, is added to the mixed solution, and the mixture is reacted at 25°C for 2 hours to obtain a reaction solution.
[0047] Example 19: This example differs from Example 17 in that polyphenols (gallate) and collagen are dispersed in a 70wt% ethanol solution at a solid-liquid ratio of 0.8:0.6g:20ml to obtain a mixed solution. Then, 1,3-diepoxybutane, accounting for 10wt% of the polyphenols, is added to the mixed solution, and the mixture is reacted at 30°C for 3 hours to obtain a reaction solution.
[0048] Example 20: This example differs from Example 17 in that 4,4'-diaminodiphenylmethane, chitosan, and glutaraldehyde are reacted at 75°C for 10 hours in a mass ratio of 1:4:0.7 to obtain a modified chitosan solution.
[0049] Example 21: This example differs from Example 17 in that 4,4'-diaminodiphenylmethane, chitosan, and glutaraldehyde are reacted at 85°C for 12 hours in a mass ratio of 1:6:0.7 to obtain a modified chitosan solution.
[0050] Example 22: This example differs from Example 17 in that the reaction solution is added dropwise to the modified chitosan solution at a volume ratio of 1:1 and subjected to microjet treatment. The microjet reactor has a single channel with a channel size of 100 μm; the pressure is 100 MPa; the injection is repeated 15 times; and the injection rate is 50 mL / min.
[0051] Example 23: The difference between this example and Example 17 is that the reaction solution is added dropwise to the modified chitosan solution at a volume ratio of 1:2 and subjected to microjet treatment. The microjet reactor has a single channel with a channel size of 150 μm; the pressure is 150 MPa; the injection is repeated 20 times; and the injection rate is 100 mL / min.
[0052] Example 24: This example differs from Example 17 in that modified polyphenols, nano silica, and silane coupling agent in a mass ratio of 5:3:0.5 are reacted at 70°C for 2.5 hours to obtain a modified corrosion-resistant filler.
[0053] Example 25: This example differs from Example 17 in that modified polyphenols, nano silica, and silane coupling agent in a mass ratio of 8:3:0.5 are reacted at 75°C for 3 hours to obtain a modified corrosion-resistant filler.
[0054] Example 26: This example differs from Example 2 in that the corrosion-resistant filler with a particle size <30μm, the gradient repair material, the flame retardant, the ceramic filler, and the methyl vinyl silicone rubber are first mixed at 40 rpm for 30 min, then the corrosion-resistant filler with a particle size of 30~80μm is added and mixed at 80 rpm for 25 min, and finally the corrosion-resistant filler with a particle size of 80~200μm is added and mixed at 110 rpm for 15 min to obtain the compound.
[0055] Example 27: This example differs from Example 2 in that the corrosion-resistant filler with a particle size <30μm, the gradient repair material, the flame retardant, the ceramic filler, and the methyl vinyl silicone rubber are first mixed at 50rpm for 40min, then the corrosion-resistant filler with a particle size of 30~80μm is added and mixed at 100rpm for 30min, and finally the corrosion-resistant filler with a particle size of 80~200μm is added and mixed at 120rpm for 20min to obtain the compound.
[0056] Example 28: The difference between this example and Example 2 is that an inhibitor is added to the mixture in proportion, mixed at 100°C for 15 minutes, and then a vulcanizing agent is added in proportion. The mixture is vulcanized at 180°C and 8MPa for 5 minutes to obtain ceramic flame-retardant silicone rubber.
[0057] Example 29: The difference between this example and Example 2 is that an inhibitor is added to the mixture in proportion, and the mixture is mixed at 120°C for 20 minutes. Then, a vulcanizing agent is added in proportion, and the mixture is vulcanized at 190°C and 10 MPa for 10 minutes to obtain ceramic flame-retardant silicone rubber.
[0058] Experimental Example: The description of this experimental example is based on the scheme described in Example 2, and aims to illustrate the practical application effect of the present invention.
[0059] The sheath materials of each embodiment were subjected to acid and alkali etching resistance tests at room temperature for 40 days. The percentage of loss was tested, and the test results are shown below. The tensile stress before damage and the tensile stress after self-healing in each embodiment were calculated to obtain the self-healing rate of the sheath material. The test results are shown below. Investigation 1: The effect of the group allocation ratio on the loss and self-repair rate of the sheath material.
[0060] The difference between Comparative Example 1 and Example 1 is that it does not contain gradient self-healing material; Depend on Figure 2The results show that Comparative Example 1 lacks a gradient self-healing material and relies on only a single repair mechanism, which cannot cope with different types of cracks and loses the synergistic repair and thermal protection advantages brought by the gradient structure. Therefore, although the loss of the sheath material in Comparative Example 1 is smaller than that in Examples 1 and 3-4, the self-healing rate is significantly reduced. Comparing Examples 1 and 3-4, it can be seen that both too small and too large a proportion of gradient repair material will reduce the self-healing performance of the sheath material. Therefore, from a comprehensive perspective, the parameters of Example 1 are relatively better.
[0061] Inquiry 2: Investigate the effect of gradient repair material on the self-healing rate of sheath material.
[0062] The difference between Comparative Example 2 and Example 1 is that only the first-gradient repair material is used; The difference between Comparative Example 3 and Example 1 is that only the second-gradient repair material was used; The difference between Comparative Example 4 and Example 1 is that the gradient positions of the first gradient repair material and the second gradient repair material are interchanged; Depend on Figure 4 The results show that the first-gradient repair material in Comparative Example 2 relies more on supramolecular forces or dynamic chemical bonds to repair microcracks, and its repair effect on larger cracks and the maintenance of mechanical strength after repair are insufficient. The second-gradient repair material in Comparative Example 3 focuses on the repair of larger cracks and mechanical strength, but lacks the characteristics of rapid response to microcracks and potential for multiple trigger repair. Comparative Example 4 does not conform to the reasonable protection logic of working from the surface to the inside, dealing with small damage first and then resisting large damage, which will reduce the overall repair efficiency and adaptability to different damage types. Therefore, the self-healing rate of the sheath materials in Comparative Examples 2 to 4 is significantly lower than that in Examples 1 and 5 to 16. Comparing Examples 1 and 5-16, it can be seen that if the preparation parameters of the inner layer repair fluid, the first-grade repair material, the outer layer repair fluid, the fiber preparation parameters, the second-grade repair material, and the gradient self-healing material are too small or too large, the corrosion resistance and self-healing performance of the sheath material will be reduced. Therefore, from a comprehensive perspective, the parameters of Example 1 are relatively better.
[0063] Investigation 3: Investigating the effect of modified corrosion-resistant filler on the loss of sheath material. (It is understood that the preparation methods and parameters of the obtained cable are based on the methods and parameters of Example 2.) The difference between Comparative Example 5 and Example 1 is that the modified chitosan solution and the reaction solution were directly mixed without microfluidic treatment; Depend on Figure 3The results show that, compared with Examples 1 and 17 to 25, by using a new type of modified corrosion-resistant filler, the density and strength of the ceramic body are improved, and a protective film with better corrosion resistance is formed. Therefore, the cable loss in Examples 17 to 25 is significantly reduced, and the corrosion resistance of the cable is significantly improved. Secondly, the mixture in Comparative Example 5 may be uneven, which can lead to agglomeration in the silicone rubber, forming defect points, and allowing corrosive media to easily penetrate. As a result, the loss of sheath material in Comparative Example 5 is greater than that in Examples 17 to 25. Comparing Examples 17 to 25, it can be seen that if the preparation parameters of the reaction solution are too small or too large, the preparation parameters of the modified chitosan solution are too small or too large, the microfluidic parameters are too small or too large, and the proportion of modified polyphenols is too small or too large, the corrosion resistance and self-healing performance of the sheath material will be reduced. Therefore, from a comprehensive perspective, the parameters of Example 17 are relatively better.
[0064] Investigation 4: Investigate the effect of the preparation of the sheath material on the loss and self-repair rate of the sheath material.
[0065] The difference between Comparative Example 6 and Example 1 is that particle size separation mixing was not performed; Depend on Figure 5 and Figure 6 The results show that the fillers of different particle sizes in Comparative Example 6 could not achieve the tightest packing, and the corrosive medium could more easily penetrate through the gaps between the fillers, and the stability of the self-healing material was also affected. Therefore, compared with Examples 2 and 26 to 29, the loss of the sheath material in Comparative Example 6 increased and the self-healing rate decreased. Comparing Examples 2 and 26-29, it can be seen that too small or too large mixing parameters and too small or too large vulcanization parameters will lead to an increase in the loss of sheath material and a decrease in the self-repair rate. Therefore, from a comprehensive perspective, the parameter effect of Example 2 is relatively better.
Claims
1. A flame-retardant ceramicized silicone rubber sheath material for low-voltage cables, characterized in that, By weight percentage, including: Corrosion-resistant filler: 3~5%; Gradient-type repair material: 5-8%; Inhibitor: 0.1~0.5; Vulcanizing agent: 1~2%; Flame retardant: 10~15%; Ceramic filler: 15~25%; Methyl vinyl silicone rubber: Balance; The corrosion-resistant filler is composed of corrosion-resistant filler with a particle size <30μm, corrosion-resistant filler with a particle size of 30~80μm, and corrosion-resistant filler with a particle size of 80~200μm, wherein the mass ratio of corrosion-resistant filler with a particle size <30μm, corrosion-resistant filler with a particle size of 30~80μm, and corrosion-resistant filler with a particle size of 80~200μm is 3:5:1~2; The gradient repair material is formed by sequentially pressing a second gradient repair material, a first gradient repair material, and a second gradient repair material in a mass ratio of 3:1:2~3.
2. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The corrosion-resistant filler is a modified corrosion-resistant filler, and the preparation method of the modified corrosion-resistant filler is as follows: Polyphenols and collagen are dispersed in an ethanol solution with a concentration of 60-70 wt% at a solid-liquid ratio of 0.8:0.6 g:15-20 ml. The polyphenols are any one of EGCG, resveratrol, and gallic acid esters to obtain a mixed solution. Then, 1,3-diepoxybutane, accounting for 8-10 wt% of the polyphenols, is added to the mixed solution and reacted at 25-30°C for 2-3 hours to obtain a reaction solution. 4,4'-diaminodiphenylmethane, chitosan, and glutaraldehyde were reacted at 75-85℃ for 10-12 h in a mass ratio of 1:4-6:0.7 to obtain a modified chitosan solution. The reaction solution was added dropwise to the modified chitosan solution at a volume ratio of 1:1 to 2 and then subjected to microjet treatment. The microjet reactor had a single channel with a channel size of 100 to 150 μm. The product was freeze-dried at a pressure of 100-150 MPa, repeated 15-20 times, and a spray rate of 50-100 mL / min to obtain modified polyphenols. The modified polyphenols, nano silica, and silane coupling agent are then reacted at 70-75℃ for 2.5-3 hours in a mass ratio of 5-8:3:0.5 to obtain the modified corrosion-resistant filler.
3. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The corrosion-resistant filler is any one of kaolin, talc, or zinc borate.
4. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The preparation method of the gradient repair material is as follows: Vinyl silicone oil, rhodium dioxide, and silane coupling agent with a concentration of 70-80 wt% are mixed at a liquid-solid ratio of 10-20 ml: 0.1 g: 0.4 g at 60-70 °C for 1-2 h to obtain an inner layer repair solution. The inner layer repair solution, emulsifier, and water are then mixed at a ratio of 6 ml: 1 g: 10-12 ml to obtain an emulsion. The pH of the emulsion was adjusted to 8-9, and dopamine hydrochloride with a concentration of 1.5-2.5 mg / ml was added to the emulsion at a mass ratio of 8-9:
1. The mixture was stirred at room temperature for 18-22 hours. After the reaction was completed, the mixture was centrifuged, and the centrifuged product was repeatedly washed with deionized water and freeze-dried to obtain the first-gradient repair material. Vinyl silicone oil, chloroplatinic acid, and ethynylcyclohexanol with a concentration of 40-50 wt% were mixed at a ratio of 8-10 ml: 0.01 g: 0.005 g for 1.5-2 h at 50-60 °C to obtain the outer layer repair solution. Alumina fiber body is impregnated in outer repair liquid at a solid-liquid ratio of 1g:5~8ml under a pressure of 0.8~1MPa and a temperature of 55~65℃. The impregnated product is then repeatedly washed with deionized water and heat-cured at 110~120℃ for 1.5~2h to obtain the second-gradient repair material. The second-gradient repair material, the first-gradient repair material, and the second-gradient repair material are laid in the mold in a certain proportion, and then hot-pressed at 120~130℃ for 1~2 minutes to obtain a gradient self-healing material.
5. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The alumina fiber body is prepared by dispersing alumina short fibers in deionized water at a solid-liquid ratio of 1g:30~40ml to obtain a dispersion, and then directionally freezing it at -25~-35℃ for 10~12h to obtain the alumina fiber body.
6. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The vulcanizing agent is benzoyl peroxide.
7. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The inhibitor is 2-methyl-3-yn-2-ol.
8. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The flame retardant is Lavaz 8685 flame retardant.
9. The flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in claim 1, characterized in that, The ceramic filler is mica powder.
10. A method for preparing a flame-retardant ceramicized silicone rubber sheath material for low-voltage cables as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. First, mix the corrosion-resistant filler with a particle size <30μm, gradient repair material, flame retardant, ceramic filler, and methyl vinyl silicone rubber at 40~50rpm for 30~40min. Then, add the corrosion-resistant filler with a particle size of 30~80μm and mix at 80~100rpm for 25~30min. Finally, add the corrosion-resistant filler with a particle size of 80~200μm and mix at 10~120rpm for 15~20min to obtain the compound. The relationship between the mixing temperature T of each mixing step, the average particle size R of the corresponding added corrosion-resistant filler, and the mass ratio m of the corresponding added corrosion-resistant filler to the total corrosion-resistant filler is as follows: T = |50-R| / m; S2. Add inhibitors to the mixture in proportion and mix at 100~120℃ for 15~20min; S3. Add vulcanizing agent according to the ratio, and vulcanize at 180~190℃ and 8~10MPa for 5~10min to obtain ceramic flame-retardant silicone rubber.