Flame-retardant silica gel cable material and preparation method thereof

Abstract

The invention relates to the technical field of cable materials, in particular to a flame-retardant silica gel cable material and a preparation method thereof. The silica gel cable material comprises the following components in parts by weight: 80-100 parts of methyl vinyl silicone rubber, 20-40 parts of fumed silica, 20-40 parts of modified magnesium hydroxide, 10-20 parts of silica powder, 2-8 parts of hydroxyl silicone oil, 0.5-3.0 parts of a vulcanizing agent, 0.5-1.5 parts of an anti-aging agent and 1-5 parts of a lubricant. The preparation method comprises the following steps: banburying methyl vinyl silicone rubber, hydroxyl silicone oil, an anti-aging agent and a lubricant to obtain a mixture; banburying the mixture, fumed silica, silica powder, modified magnesium hydroxide and a vulcanizing agent to obtain a rubber compound; the rubber compound is sequentially subjected to first-stage vulcanization and second-stage vulcanization to obtain the silica gel cable material which has excellent flame retardant property and mechanical property, so that the service life of the silica gel cable material is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of cable materials, in particular to a flame retardant silicone cable material and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology and the widespread application of intelligent devices, cables, as basic components for power and signal transmission, have received increasing attention for their performance and safety. Silicone rubber is a type of polymer compound with repeated Si-O bonds as the main chain and side chains of organic groups such as methyl, vinyl, and phenyl. Silicone rubber has very good flexibility and chemical stability, and has a certain degree of self-extinguishing properties in flames. At the same time, the gas produced when pure silicone rubber burns is non-toxic and will not drip. The residue after combustion is silicon dioxide, which can cover the surface of the polymer and play a role in blocking heat and mass transfer. Due to these excellent properties of silicone rubber, it is widely used in cables, wires, aerospace, automobiles, and chemicals.

[0003] However, silicone rubber is flammable and will continue to burn once it catches fire, posing a potential combustion risk, which to some extent limits its application in the wire and cable industry.

[0004] Therefore, we propose a flame retardant silicone cable material and a preparation method thereof. Summary of the invention

[0005] The object of the present invention is to provide a flame retardant silicone cable material and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a flame retardant silicone cable material comprises the following steps: Step S1: kneading methyl vinyl silicone rubber, hydroxy silicone oil, anti-aging agent and lubricant at 90-110° C. for 2-5 minutes to obtain a mixture; Step S2: kneading the mixture, fumed silica, silicon powder and modified magnesium hydroxide at 110-130° C. for 1-3 min, adding a vulcanizing agent, and kneading at 140-160° C. for 3-5 min to obtain a rubber compound; and sequentially performing a first-stage vulcanization and a second-stage vulcanization on the rubber compound to obtain a silicone cable material.

[0007] Furthermore, the silicone cable material includes the following components by weight: 80-100 parts of methyl vinyl silicone rubber, 20-40 parts of fumed silica, 20-40 parts of modified magnesium hydroxide, 10-20 parts of silicon micropowder, 2-8 parts of hydroxy silicone oil, 0.5-3.0 parts of vulcanizing agent, 0.5-1.5 parts of anti-aging agent, and 1-5 parts of lubricant.

[0008] Further, the preparation method of the modified magnesium hydroxide is as follows: Step A: Mix magnesium hydroxide, anhydrous ethanol, deionized water and 3-mercaptopropyltriethoxysilane evenly, adjust the pH of the system to 3-5 with acetic acid, react at 70-80° C. for 4-6 hours, and obtain mercapto magnesium hydroxide after filtering, washing and drying; Step B: Mix the thiolated magnesium hydroxide, the flame retardant and the photoinitiator evenly, and irradiate with ultraviolet light to obtain modified magnesium hydroxide.

[0009] Furthermore, in step A, the mass ratio of magnesium hydroxide, anhydrous ethanol, deionized water and 3-mercaptopropyltriethoxysilane is 1:(10-15):(2-4):(0.3-0.5).

[0010] Furthermore, in step B, the mass ratio of thiolated magnesium hydroxide, flame retardant and photoinitiator is 1:(1-3):(0.03-0.05).

[0011] Furthermore, in step B, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the process conditions of ultraviolet irradiation are: irradiation wavelength 360-400nm, irradiation time 20-40min, irradiation intensity 20-35mW / cm 2 .

[0012] Furthermore, the preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, vanillin, phenylphosphonothioic acid dichloride, ethyl acetate and triethylamine are mixed evenly, reacted at 60-70° C. for 8-10 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, the aldehyde compound, 4-hydroxyphenylboronic acid, N,N-dimethylformamide and triethylamine are mixed evenly, reacted at 60-70°C for 8-10 hours, filtered, washed and dried to obtain an intermediate; Step (3): 2,4-diamino-6-diallylamino-1,3,5-triazine, the intermediate and N,N-dimethylformamide are mixed evenly, reacted at 65-75°C for 3-5h, DOPO is added, the temperature is raised to 85-95°C, the reaction is performed for 16-18h, the mixture is cooled to room temperature, filtered, washed and dried to obtain a flame retardant.

[0013] In the above technical scheme, by controlling the slight excess of phenylphosphonothioyl dichloride, one -Cl in phenylphosphonothioyl dichloride reacts with the hydroxyl group in vanillin to obtain an aldehyde compound; then the hydroxyl group in 4-hydroxyphenylboronic acid reacts with the remaining -Cl in the aldehyde compound to obtain an intermediate containing phenylboronic acid group; finally, the amino group in 2,4-diamino-6-diallylamino-1,3,5-triazine reacts with the aldehyde group in the intermediate to form an imine bond, which can react with the PH bond in DOPO to obtain a flame retardant containing N, S, P, and B elements.

[0014] Furthermore, in the step (1), the mass ratio of vanillin, phenylphosphonothioic acid dichloride, ethyl acetate and triethylamine is 1: (1.4-1.6): (6-8): (0.6-0.8).

[0015] Furthermore, in the step (2), the mass ratio of the aldehyde compound, 4-hydroxyphenylboric acid, N,N-dimethylformamide and triethylamine is 1:(0.4-0.6):(8-10):(0.6-0.8).

[0016] Furthermore, in the step (3), the mass ratio of 2,4-diamino-6-diallylamino-1,3,5-triazine, the intermediate, N,N-dimethylformamide and DOPO is 1:(2-4):(20-30):(3-5).

[0017] Furthermore, the antioxidant is antioxidant RD.

[0018] Furthermore, the vulcanizing agent is a dipentadienyl vulcanizing agent.

[0019] Furthermore, the lubricant is one of polyethylene wax, stearic acid and zinc stearate.

[0020] Furthermore, the process conditions of the one-stage vulcanization are: carried out on a flat vulcanizing machine, at a temperature of 160-170° C., a molding pressure of 10-15 MPa, and a time of 10-30 min.

[0021] Furthermore, the process conditions of the two-stage vulcanization are: carried out in a forced air drying oven, at a temperature of 180-200° C., and for 1-3 hours.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. A flame-retardant silicone cable material and a preparation method thereof of the present invention comprises the following steps: controlling phenylphosphonothioyl dichloride to be slightly excessive, so that a -Cl in phenylphosphonothioyl dichloride reacts with a hydroxyl group in vanillin to obtain an aldehyde compound; then the hydroxyl group in 4-hydroxyphenylboronic acid reacts with the remaining -Cl in the aldehyde compound to obtain an intermediate containing phenylboronic acid group; finally, the amino group in 2,4-diamino-6-diallylamino-1,3,5-triazine reacts with the aldehyde group in the intermediate to form an imine bond, which can react with the PH bond in DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), thereby further improving the flame retardancy and obtaining a flame retardant containing N, S, P, and B elements, wherein the nitrogen element can form a gas phase flame retardant layer to inhibit flame propagation; the sulfur and phosphorus elements can form a carbonized layer at high temperature to further isolate oxygen and slow down the combustion process; and the boron element enhances the thermal stability and oxidation resistance of the material and improves the overall flame retardant effect.

[0023] At the same time, the flame retardant also contains triazine structure and olefin group. The triazine structure has high rigidity and stability, which can not only enhance the thermal stability of the material, but also form a carbonized layer at high temperature, further improving the flame retardant performance; the olefin group can ensure the subsequent reaction and is easy to cross-link or modify with other functional groups, thereby improving the chemical stability of the material.

[0024] 2. A flame-retardant silicone cable material and a preparation method thereof of the present invention utilizes 3-mercaptopropyltriethoxysilane to carry out surface modification of magnesium hydroxide, and organic silicon molecular chains can be modified to the surface of magnesium hydroxide to obtain mercapto magnesium hydroxide. This modification enables the mercapto magnesium hydroxide and the silicone rubber matrix to have the same organic silicon structural monomer, thereby improving the affinity of the two and further enhancing the compatibility between the two; at the same time, the mercapto group on the surface of the mercapto magnesium hydroxide can undergo a mercapto-ene click reaction with the allyl group in the flame retardant to form a stable chemical bond, which together exerts a synergistic effect, thereby significantly improving the flame retardant properties and mechanical properties of the material. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In this embodiment, the methyl vinyl silicone rubber raw rubber is: model 110-2, with an average molar mass of 65×10 4g / mol, sourced from Hesheng Silicon Industry Co., Ltd.; fumed silica: model HL380, sourced from Hubei Huifu Nanomaterials Co., Ltd.; silicon micropowder: particle size of 1250 mesh, sourced from Chifeng Hengshuo Silica Processing Co., Ltd.; magnesium hydroxide: particle size of 2500 mesh, sourced from Shandong Boxin Chemical Co., Ltd.; hydroxy silicone oil: model JP-107, sourced from Shenzhen Jipeng Silicon Fluoride Materials Co., Ltd.; dipentadienyl vulcanizing agent: sourced from Shandong Hanyue Chemical Co., Ltd.; anti-aging agent RD: sourced from Shijiazhuang Zhongdao Chemical Technology Co., Ltd.; lubricant: stearic acid, model 630, sourced from Shanghai Shengyue International Trade Co., Ltd.

[0027] In the following examples and comparative examples, 1 part is equal to 10 g.

[0028] Embodiment 1: A method for preparing a flame retardant silicone cable material, comprising the following process: Step S1: knead 80 parts of methyl vinyl silicone rubber, 2 parts of hydroxy silicone oil, 0.5 parts of antioxidant RD, and 1 part of stearic acid at 90° C. for 2 minutes to obtain a mixture; Step S2: kneading the mixture, 20 parts of fumed silica, 10 parts of silicon powder and 20 parts of modified magnesium hydroxide at 110° C. for 1 min, adding 0.5 parts of dipentadienyl vulcanizing agent, and kneading at 140° C. for 3 min to obtain a rubber compound; subjecting the rubber compound to a first-stage vulcanization (carried out on a flat vulcanizing machine at a temperature of 160° C., a molding pressure of 10 MPa, and a time of 10 min) and a second-stage vulcanization (carried out in a blast drying oven at a temperature of 180° C. and a time of 1 h) in sequence to obtain a silicone cable material; The preparation method of modified magnesium hydroxide is as follows: Step A: 15 parts of magnesium hydroxide, 150 parts of anhydrous ethanol, 30 parts of deionized water and 4.5 parts of 3-mercaptopropyltriethoxysilane are mixed evenly, acetic acid is used to adjust the pH of the system to 3, the reaction is carried out at 70° C. for 4 hours, and after filtering, washing and drying, thiolated magnesium hydroxide is obtained; Step B: 15 parts of magnesium thiohydroxide, 15 parts of flame retardant and 0.45 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (the process conditions of ultraviolet light were: irradiation wavelength 360nm, irradiation time 20min, irradiation intensity 20mW / cm 2 ), to obtain modified magnesium hydroxide; The preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, 10 parts of vanillin, 14 parts of phenylphosphonothioic acid dichloride, 60 parts of ethyl acetate and 6 parts of triethylamine are mixed evenly, reacted at 60° C. for 8 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, 10 parts of an aldehyde compound, 4 parts of 4-hydroxyphenylboric acid, 100 parts of N,N-dimethylformamide and 6 parts of triethylamine are mixed evenly, reacted at 60° C. for 8 hours, filtered, washed and dried to obtain an intermediate; Step (3): 5 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 10 parts of the intermediate and 100 parts of N,N-dimethylformamide are mixed evenly, reacted at 65°C for 3 hours, 15 parts of DOPO are added, the temperature is raised to 85°C, the reaction is performed for 16 hours, and the mixture is cooled to room temperature. After filtering, washing and drying, a flame retardant is obtained.

[0029] Embodiment 2: A method for preparing a flame-retardant silicone cable material, comprising the following process: Step S1: knead 90 parts of methyl vinyl silicone rubber, 6 parts of hydroxy silicone oil, 1 part of antioxidant RD, and 3 parts of stearic acid at 100° C. for 3 minutes to obtain a mixture; Step S2: kneading the mixture, 30 parts of fumed silica, 15 parts of silicon powder and 30 parts of modified magnesium hydroxide at 120°C for 2 minutes, adding 2 parts of dipentadienyl vulcanizing agent, and kneading at 150°C for 4 minutes to obtain a rubber mix; subjecting the rubber mix to a first-stage vulcanization (carried out on a flat vulcanizer, at a temperature of 165°C, a molding pressure of 12Mpa, and a time of 20 minutes) and a second-stage vulcanization (carried out in a blast drying oven, at a temperature of 190°C and a time of 2 hours) in sequence to obtain a silicone cable material; The preparation method of modified magnesium hydroxide is as follows: Step A: 30 parts of magnesium hydroxide, 360 parts of anhydrous ethanol, 90 parts of deionized water and 12 parts of 3-mercaptopropyltriethoxysilane are mixed evenly, acetic acid is used to adjust the pH of the system to 4, the reaction is carried out at 75° C. for 5 hours, and after filtering, washing and drying, mercapto magnesium hydroxide is obtained; Step B: 30 parts of magnesium thiohydroxide, 60 parts of flame retardant and 1.2 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (the process conditions of ultraviolet light were: irradiation wavelength 380nm, irradiation time 30min, irradiation intensity 30mW / cm 2 ), to obtain modified magnesium hydroxide; The preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, 60 parts of vanillin, 90 parts of phenylphosphonothioic acid dichloride, 420 parts of ethyl acetate and 42 parts of triethylamine are mixed evenly, reacted at 65° C. for 9 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, 60 parts of an aldehyde compound, 30 parts of 4-hydroxyphenylboric acid, 540 parts of N,N-dimethylformamide and 42 parts of triethylamine were mixed evenly, reacted at 65°C for 9 hours, and filtered, washed and dried to obtain an intermediate; Step (3): 20 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 60 parts of the intermediate and 500 parts of N,N-dimethylformamide are mixed evenly, reacted at 70°C for 4 hours, 80 parts of DOPO are added, the temperature is raised to 90°C, the reaction is carried out for 17 hours, and the mixture is cooled to room temperature. After filtering, washing and drying, a flame retardant is obtained.

[0030] Embodiment 3: A method for preparing a flame retardant silicone cable material, comprising the following process: Step S1: kneading 100 parts of methyl vinyl silicone rubber, 8 parts of hydroxy silicone oil, 1.5 parts of antioxidant RD, and 5 parts of stearic acid at 110° C. for 5 minutes to obtain a mixture; Step S2: kneading the mixture, 40 parts of fumed silica, 20 parts of silicon powder and 40 parts of modified magnesium hydroxide at 130° C. for 3 min, adding 3.0 parts of dipentadienyl vulcanizing agent, and kneading at 160° C. for 5 min to obtain a rubber compound; subjecting the rubber compound to a first-stage vulcanization (carried out on a flat vulcanizing machine at a temperature of 170° C., a molding pressure of 15 MPa, and a time of 30 min) and a second-stage vulcanization (carried out in a blast drying oven at a temperature of 200° C. and a time of 3 h) in sequence to obtain a silicone cable material; The preparation method of modified magnesium hydroxide is as follows: Step A: 10 parts of magnesium hydroxide, 150 parts of anhydrous ethanol, 4 parts of deionized water and 5 parts of 3-mercaptopropyltriethoxysilane are mixed evenly, acetic acid is used to adjust the pH of the system to 5, the reaction is carried out at 80° C. for 6 hours, and after filtering, washing and drying, mercapto magnesium hydroxide is obtained; Step B: 10 parts of magnesium thiohydroxide, 40 parts of flame retardant and 0.5 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (the process conditions of ultraviolet light were: irradiation wavelength 400nm, irradiation time 40min, irradiation intensity 35mW / cm 2 ), to obtain modified magnesium hydroxide; The preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, 30 parts of vanillin, 48 parts of phenylphosphonothioic acid dichloride, 240 parts of ethyl acetate and 24 parts of triethylamine are mixed evenly, reacted at 70° C. for 10 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, 30 parts of an aldehyde compound, 24 parts of 4-hydroxyphenylboric acid, 300 parts of N,N-dimethylformamide and 24 parts of triethylamine are mixed evenly, reacted at 70° C. for 10 hours, filtered, washed and dried to obtain an intermediate; Step (3): 8 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 32 parts of the intermediate and 240 parts of N,N-dimethylformamide are mixed evenly, reacted at 75°C for 5 hours, 40 parts of DOPO are added, the temperature is raised to 95°C, the reaction is performed for 18 hours, and the mixture is cooled to room temperature. After filtering, washing and drying, a flame retardant is obtained.

[0031] Comparative Example 1: A method for preparing a flame-retardant silicone cable material, comprising the following processes: Step S1: knead 90 parts of methyl vinyl silicone rubber, 6 parts of hydroxy silicone oil, 1 part of antioxidant RD, and 3 parts of stearic acid at 100° C. for 3 minutes to obtain a mixture; Step S2: kneading the mixture, 30 parts of fumed silica, 15 parts of silicon powder and 40 parts of magnesium hydroxide at 120° C. for 2 minutes, adding 2 parts of dipentadienyl vulcanizing agent, and kneading at 150° C. for 4 minutes to obtain a rubber compound; subjecting the rubber compound to a first-stage vulcanization (carried out on a flat vulcanizing machine, at a temperature of 165° C., a molding pressure of 12 MPa, and a time of 20 minutes) and a second-stage vulcanization (carried out in a blast drying oven, at a temperature of 190° C. and a time of 2 hours) in sequence to obtain a silicone cable material; Compared with Example 2, Comparative Example 1 does not include the preparation method of modified magnesium hydroxide, the modified magnesium hydroxide in step S2 is replaced with magnesium hydroxide of the same mass, and the other steps are the same as Example 2.

[0032] Comparative Example 2: A method for preparing a flame-retardant silicone cable material, comprising the following processes: The preparation method of modified magnesium hydroxide is as follows: Step A: 30 parts of magnesium hydroxide, 360 parts of anhydrous ethanol, 90 parts of deionized water and 12 parts of 3-mercaptopropyltriethoxysilane are mixed evenly, acetic acid is used to adjust the pH of the system to 4, the reaction is carried out at 75° C. for 5 hours, and after filtering, washing and drying, mercapto magnesium hydroxide is obtained; Step B: 30 parts of magnesium thiohydroxide, 15 parts of flame retardant and 1.2 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (the process conditions of ultraviolet light were: irradiation wavelength 380nm, irradiation time 30min, irradiation intensity 30mW / cm 2 ), to obtain modified magnesium hydroxide; Compared with Example 2, in step B of Comparative Example 2, the mass ratio of thiolated magnesium hydroxide to the flame retardant is 1:0.5, and the other steps are the same as those in Example 2.

[0033] Comparative Example 3: A method for preparing a flame-retardant silicone cable material, comprising the following processes: The preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, 60 parts of vanillin, 42 parts of phenylphosphonothioic acid dichloride, 420 parts of ethyl acetate and 42 parts of triethylamine are mixed evenly, reacted at 65° C. for 9 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, 60 parts of an aldehyde compound, 30 parts of 4-hydroxyphenylboric acid, 540 parts of N,N-dimethylformamide and 42 parts of triethylamine were mixed evenly, reacted at 65°C for 9 hours, and filtered, washed and dried to obtain an intermediate; Step (3): 20 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 60 parts of the intermediate and 500 parts of N,N-dimethylformamide are mixed evenly, reacted at 70°C for 4 hours, 80 parts of DOPO are added, the temperature is raised to 90°C, the reaction is performed for 17 hours, the mixture is cooled to room temperature, filtered, washed and dried to obtain a flame retardant; Compared with Example 2, in step (1) of Comparative Example 3, the mass ratio of vanillin to phenylphosphonothioate dichloride is 1:0.7, and the other steps are the same as those of Example 2.

[0034] Comparative Example 4: A method for preparing a flame-retardant silicone cable material, comprising the following processes: Step S1: knead 90 parts of methyl vinyl silicone rubber, 6 parts of hydroxy silicone oil, 1 part of antioxidant RD, and 3 parts of stearic acid at 100° C. for 3 minutes to obtain a mixture; Step S2: kneading the mixture, 30 parts of fumed silica, 15 parts of silicon powder and 30 parts of magnesium hydroxide at 120° C. for 2 minutes, adding 2 parts of dipentadienyl vulcanizing agent, and kneading at 150° C. for 4 minutes to obtain a rubber compound; subjecting the rubber compound to a first-stage vulcanization (carried out on a flat vulcanizer, at a temperature of 165° C., a molding pressure of 12 MPa, and a time of 20 minutes) and a second-stage vulcanization (carried out in a blast drying oven, at a temperature of 190° C. and a time of 2 hours) in sequence to obtain a silicone cable material; Compared with Example 2, in Comparative Example 4, the modified magnesium hydroxide in step S2 is replaced with the same mass of thiolated magnesium hydroxide, and the other steps are the same as those in Example 2.

[0035] Experiment: Take the silicone cable materials obtained in Examples 1-3 and Comparative Examples 1-4, prepare samples, test their properties respectively and record the test results: The oxygen index was determined according to GB / T 2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method Part 2: Room Temperature Test", and the sample size was 125mm×6.5mm×3mm; the tensile strength was determined according to GB / T 528-2009 standard, and the tensile rate was 50mm / min.

[0036] Test Results According to the data in the above table, we can clearly draw the following conclusions: 1. Compared with Examples 1-3, the oxygen index and tensile strength of the products obtained in Comparative Examples 1 and 2 are both reduced, indicating that the modified magnesium hydroxide prepared by the present invention has better flame retardant effect and mechanical properties than the unmodified magnesium hydroxide; at the same time, when the amount of flame retardant added in the modified magnesium hydroxide is reduced, the flame retardant performance will decrease, indicating that the performance of the modified magnesium hydroxide prepared by the present invention is affected by the composition ratio thereof, and the composition ratio within the range is selected to prepare a modified magnesium hydroxide with better flame retardant effect.

[0037] 2. Compared with Examples 1-3, the oxygen index of the product obtained in Comparative Example 3 is reduced, which indicates that when the amount of phenylphosphonothioyl dichloride added is reduced, the vanillin and chlorine atoms react completely, resulting in the inability to effectively graft with 4-hydroxyphenylboronic acid in the subsequent reaction, thereby reducing the flame retardant performance of the material. Therefore, it can be seen that the performance of the flame retardant prepared by the present invention is affected by the ratio of each reagent in its preparation process. By selecting the mass ratio within the range, the prepared flame retardant has an excellent flame retardant effect.

[0038] 3. Compared with Examples 1-3, the oxygen index and tensile strength of the product obtained in Comparative Example 4 are both reduced. It can be seen that the magnesium hydroxide modified with mercaptosilane can improve its dispersibility, which is beneficial to improving the flame retardant effect.

[0039] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a flame retardant silicone cable material, characterized in that: The steps include: Step S1: kneading methyl vinyl silicone rubber, hydroxy silicone oil, anti-aging agent and lubricant at 90-110° C. for 2-5 minutes to obtain a mixture; Step S2: kneading the mixture, fumed silica, silicon powder and modified magnesium hydroxide at 110-130° C. for 1-3 min, adding a vulcanizing agent, and kneading at 140-160° C. for 3-5 min to obtain a rubber compound; and sequentially performing a first-stage vulcanization and a second-stage vulcanization on the rubber compound to obtain a silicone cable material; The silicone cable material comprises the following components by weight: 80-100 parts of methyl vinyl silicone rubber, 20-40 parts of fumed silica, 20-40 parts of modified magnesium hydroxide, 10-20 parts of silicon micropowder, 2-8 parts of hydroxy silicone oil, 0.5-3.0 parts of vulcanizing agent, 0.5-1.5 parts of anti-aging agent, and 1-5 parts of lubricant; The preparation method of the modified magnesium hydroxide is as follows: Step A: Mix magnesium hydroxide, anhydrous ethanol, deionized water and 3-mercaptopropyltriethoxysilane evenly, adjust the pH of the system to 3-5 with acetic acid, react at 70-80° C. for 4-6 hours, and obtain mercapto magnesium hydroxide after filtering, washing and drying; Step B: uniformly mixing thiolated magnesium hydroxide, a flame retardant and a photoinitiator, and irradiating the mixture with ultraviolet light to obtain modified magnesium hydroxide; The preparation method of the flame retardant is as follows: Step (1): Under nitrogen protection, vanillin, phenylphosphonothioic acid dichloride, ethyl acetate and triethylamine are mixed evenly, reacted at 60-70° C. for 8-10 hours, filtered, washed and dried to obtain an aldehyde compound; Step (2): Under nitrogen protection, the aldehyde compound, 4-hydroxyphenylboronic acid, N,N-dimethylformamide and triethylamine are mixed evenly, reacted at 60-70°C for 8-10 hours, filtered, washed and dried to obtain an intermediate; Step (3): 2,4-diamino-6-diallylamino-1,3,5-triazine, the intermediate and N,N-dimethylformamide are mixed evenly, reacted at 65-75°C for 3-5h, DOPO is added, the temperature is raised to 85-95°C, the reaction is performed for 16-18h, the mixture is cooled to room temperature, filtered, washed and dried to obtain a flame retardant.

2. The method for preparing a flame-retardant silicone cable material according to claim 1, characterized in that: In the step B, the mass ratio of the mercaptohydroxide magnesium, the flame retardant and the photoinitiator is 1:(1-3):(0.01-0.03).

3. The method for preparing a flame-retardant silicone cable material according to claim 1, characterized in that: In the step (1), the mass ratio of vanillin, phenylphosphonothioic acid dichloride, ethyl acetate and triethylamine is 1: (1.4-1.6): (6-8): (0.6-0.8).

4. The method for preparing a flame-retardant silicone cable material according to claim 1, characterized in that: In the step (3), the mass ratio of 2,4-diamino-6-diallylamino-1,3,5-triazine, the intermediate, N,N-dimethylformamide and DOPO is 1:(2-4):(20-30):(3-5).

5. The method for preparing a flame retardant silicone cable material according to claim 1, characterized in that: The vulcanizing agent is a dipentadienyl vulcanizing agent.

6. The method for preparing a flame retardant silicone cable material according to claim 1, characterized in that: The antioxidant is antioxidant RD.

7. A flame retardant silicone cable material, characterized in that: The flame-retardant silicone cable material is prepared by the method for preparing a flame-retardant silicone cable material according to any one of claims 1 to 6.

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