Flame-retardant rubber and plastic thermal insulation material and preparation method thereof

Abstract

The invention relates to a flame-retardant rubber and plastic thermal insulation material and a preparation method thereof, and belongs to the technical field of high polymer materials. The flame-retardant rubber-plastic thermal insulation material comprises the following components in parts by weight: 50-75 parts of nitrile rubber, 20-45 parts of PVC resin, 10-15 parts of a plasticizer, 1-10 parts of a foaming agent, 1-5 parts of a foaming promoter, 10-40 parts of a composite flame retardant and 2-6 parts of a modified anti-aging agent, cyclohexanehexol phosphate in the composite flame retardant is heated and dehydrated into phosphoric acid, a barrier layer is formed to inhibit release of combustible materials, and dimethylallylamine combusts to absorb heat and cooperates with phosphorus-oxygen double bonds for flame retardance; a pre-product in the modified anti-aging agent reacts with a free radical of a rubber molecular chain, so that the heat resistance and the aging resistance of the material are improved, a maleimide group enhances an intermolecular acting force, the rigidity and the heat resistance of the molecular chain are improved, and material aging caused by high temperature is reduced; the flame-retardant rubber and plastic thermal insulation material prepared by the invention not only has an excellent anti-aging effect, but also has good flame retardance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a flame retardant rubber-plastic thermal insulation material and a preparation method thereof. Background Art

[0002] With the advancement of science and technology and the vigorous development of industry, thermal insulation materials are widely used in central air-conditioning, construction, chemical industry, automobile and electrical appliances and other fields, and are increasingly favored by the market.

[0003] Traditional thermal insulation materials are difficult to use for a long time due to their defects such as being not resistant to water, being susceptible to moisture, being easy to burn, and possibly releasing harmful gases in actual applications. In contrast, rubber-plastic thermal insulation materials, as elastic closed-cell foam materials, not only have the properties of low thermal conductivity, moisture resistance, vibration reduction and noise reduction, but also have the advantages of a long service life and environmental protection. They are mainly made of nitrile rubber and PVC resin, and have good oil resistance, physical and mechanical properties and processing properties. However, when exposed to sunlight for a long time, the organic matter in the rubber-plastic materials will undergo photooxidation reaction, resulting in performance degradation. In addition, although rubber-plastic thermal insulation materials have certain flame retardancy, with the increase in actual application needs, their own flame retardancy no longer meets the needs. Therefore, the research and development of rubber-plastic thermal insulation materials with excellent anti-aging and flame retardancy has important practical significance and application value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a flame retardant rubber-plastic thermal insulation material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A flame retardant rubber-plastic thermal insulation material and a preparation method thereof, comprising the following raw materials in parts by weight: 50-75 parts of nitrile rubber, 20-45 parts of PVC resin, 10-15 parts of plasticizer, 1-10 parts of foaming agent, 1-5 parts of foaming aid, 10-40 parts of composite flame retardant, and 2-6 parts of modified anti-aging agent;

[0007] The plasticizer is trialkyl phosphate;

[0008] The foaming agent is azodicarbonamide;

[0009] The foaming auxiliary agent is zinc oxide.

[0010] The composite flame retardant is prepared by the following method:

[0011] Step A1: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, N,N-dimethylformamide and dimethylallylamine were mixed, stirred at 150° C. for 9 h, filtered, washed, and dried under vacuum at 60° C. for 24 h to obtain a compound;

[0012] Further, the usage ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, N,N-dimethylformamide, and dimethylallylamine is 0.15-0.25 mol:40-60 mL:10.65-17.75 g;

[0013] Step A2: uniformly mix the compound, 1-chlorohexane and methanol, react for 12 hours, cool to room temperature, and dry under nitrogen protection to obtain an intermediate product;

[0014] Furthermore, the usage ratio of the compound, 1-chlorohexane, and methanol is 1-2 mol: 1-2 mol: 20-50 mL;

[0015] Step A3: Disperse cyclohexane hexanol phosphate uniformly in deionized water, adjust the pH to 6, add the intermediate product and mix evenly, stir at 40° C. for 2 h, centrifuge and wash, to obtain a composite flame retardant;

[0016] Furthermore, the usage ratio of cyclohexanehexol phosphate, deionized water, and intermediate product is 11.2-12.1 g: 100-120 mL: 2-4 g.

[0017] The modified antioxidant is prepared by the following method:

[0018] Step B1: Evenly mix catechol and 4-vinylaniline, heat to 60-70°C, then add anhydrous ferric chloride, deionized water and toluene, stir, heat to 220°C within 20-30min, react for 5h, cool to 100-110°C, filter while hot, and distill under reduced pressure to obtain a pre-product;

[0019] Further, the dosage ratio of catechol, 4-vinylaniline, anhydrous ferric chloride, deionized water, and toluene is 22-26 g: 47.6-51.9 mL: 0.71-1.07 g: 25-40 mL: 10 mL;

[0020] Step B2: Disperse N-phenylmaleimide and benzoyl peroxide in xylene, add the pre-product and stir evenly, heat to 90°C under nitrogen protection for 4.5h, distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain a modified antioxidant;

[0021] Furthermore, the usage ratio of N-phenylmaleimide, benzoyl peroxide, xylene and pre-product is 3-5 g: 0.16 g: 70 mL: 10-12 g.

[0022] A method for preparing a flame retardant rubber-plastic thermal insulation material, comprising the following steps:

[0023] S1. Put nitrile rubber, PVC resin, plasticizer, composite flame retardant and modified anti-aging agent into a high-speed mixer, mix for 10-15 minutes, heat to 100-120° C., put into a low-speed mixer, cool to 30-50° C., discharge, and place for 8-24 hours to obtain a pretreated material;

[0024] S2, adding the foaming agent and the foaming aid to the pretreated material, mixing for 4-10 minutes, discharging the material, and obtaining a mixed rubber;

[0025] S3. Extrude the mixed rubber into a rubber extruder. The temperature of the extruder feeding section is 15-20°C, the temperature of the plasticizing section is 20-25°C, and the temperature of the die head section is 25-30°C. Then, the mixed rubber is transported to a foaming furnace through a guide wheel, foamed for 3-5 minutes, cooled and cut to obtain a flame-retardant rubber-plastic thermal insulation material. The foaming furnace is divided into 7 temperature control zones, wherein the temperature of the first zone is 100-120°C, the second zone is 120-125°C, the third zone is 125-135°C, the fourth zone is 135-140°C, the fifth zone is 140-150°C, the sixth zone is 150-160°C, and the seventh zone is 160-170°C.

[0026] Beneficial effects of the present invention:

[0027] The flame-retardant rubber-plastic thermal insulation material of the invention has good anti-aging effect and excellent flame retardancy, thereby extending the service life of the material.

[0028] The composite flame retardant prepared by the invention comprises the following steps: firstly, the carbon-carbon double bond of dimethylallylamine is reacted with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to synthesize a compound; secondly, the chlorine atom of 1-chlorohexane is used to make the compound undergo a quaternary ammonium salt reaction to synthesize an intermediate product with a positive charge; and finally, the composite flame retardant is prepared by utilizing the electrostatic interaction between the positive charge of the intermediate product and the negative charge of cyclohexanehexol phosphate. Cyclohexanehexol phosphate in the composite flame retardant is a widely available and environmentally friendly biomass renewable resource. It is dehydrated into phosphoric acid when heated, which promotes surface carbonization to form a barrier layer, effectively isolates air and heat, inhibits the release of combustible volatiles, and achieves a flame retardant effect. Dimethylallylamine absorbs a large amount of heat during combustion, reduces the temperature and slows down the combustion rate. At the same time, it forms a protective film during the combustion process, isolates oxygen and heat, interrupts the combustion chain reaction, reduces the generation of combustibles, releases non-combustible gases, and reduces the oxygen concentration in the combustion zone. In addition, the phosphorus-nitrogen flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, as a phosphaphenanthrene compound with high thermal stability, promotes the formation of a dense and continuous carbon layer during combustion, effectively isolates oxygen, blocks the exchange of heat and combustible gases, inhibits combustion, and also cooperates with the phosphorus-oxygen double bond to achieve flame retardancy, thereby extending its service life. In addition, the composite flame retardant prepared by the present invention is halogen-free, helps to reduce environmental pollution and damage to the ecosystem, is harmless to human health, and achieves sustainable development.

[0029] The modified anti-aging agent prepared by the present invention has the advantage of a macromolecular polymer and exhibits anti-aging performance that exceeds that of a traditional small-molecule modified anti-aging agent. The modified anti-aging agent first utilizes the hydroxyl group of catechol and the amino group of 4-vinylaniline for dehydration condensation to synthesize a pre-product; and then utilizes the pre-product and the carbon-carbon double bond of N-phenylmaleimide for copolymerization to synthesize the modified anti-aging agent. The pre-product in the modified anti-aging agent can react with free radicals in the rubber molecular chain, effectively inhibiting the oxidation reaction caused by oxygen, ultraviolet rays, and ozone, thereby delaying the aging speed of rubber products, improving the heat resistance and aging resistance of the material, and extending the service life. At the same time, the pre-product is also closely combined with the matrix to enhance the stability of the internal structure of the material, improve the resistance to external adverse factors, and effectively optimize the performance of the material; in addition, the maleimide group increases the glass transition temperature and melting point of the material by enhancing the intermolecular force, increases the rigidity and heat resistance of the molecular chain, and reduces the aging of the material caused by high-temperature thermal aging; in addition, the modified anti-aging agent can copolymerize with the carbon-carbon double bond of polyvinyl chloride to solve the migration, incompatibility and volatilization problems of traditional modified anti-aging agents. DETAILED DESCRIPTION

[0030] 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.

[0031] Embodiment 1: A method for preparing a flame retardant rubber-plastic thermal insulation material, comprising the following steps:

[0032] S1. Weigh the raw materials by weight: 50 parts of nitrile rubber, 20 parts of PVC resin, 10 parts of plasticizer, 1 part of foaming agent, 1 part of foaming aid, 10 parts of composite flame retardant (prepared by this embodiment), and 2 parts of modified anti-aging agent (prepared by this embodiment); put the nitrile rubber, PVC resin, trialkyl phosphate, composite flame retardant and modified anti-aging agent into a high-speed mixer, mix for 10 minutes, heat to 100° C., put into a low-speed mixer, cool to 30° C., discharge the material, and place for 8 hours to obtain a pretreated material;

[0033] S2, adding azodicarbonamide and zinc oxide to the pretreated material, mixing for 4 minutes, discharging the material, and obtaining a mixed rubber;

[0034] S3, extrude the mixed rubber into a rubber extruder, the temperature of the extruder feeding section is 15°C, the temperature of the plasticizing section is 20°C, and the temperature of the die section is 25°C, and then transport it to the foaming furnace through the guide wheel, foam for 3 minutes, cool and cut, and obtain a flame-retardant rubber-plastic insulation material. The foaming furnace is divided into 7 temperature control zones, wherein the temperature of the first zone is 100°C, the second zone is 120°C, the third zone is 125°C, the fourth zone is 135°C, the fifth zone is 140°C, the sixth zone is 150°C, and the seventh zone is 160°C;

[0035] The composite flame retardant is prepared by the following method:

[0036] Step A1: 0.15 mol 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 mL N,N-dimethylformamide and 10.65 g dimethylallylamine were mixed, stirred at 150° C. for 9 h, filtered, washed, and dried under vacuum at 60° C. for 24 h to obtain a compound;

[0037] Step A2: 1 mol of the compound, 1 mol of 1-chlorohexane and 20 mL of methanol were mixed evenly, reacted for 12 h, cooled to room temperature, and dried under nitrogen protection to obtain an intermediate product;

[0038] Step A3: 11.2 g of cyclohexane hexanol phosphate was uniformly dispersed in 100 mL of deionized water, the pH was adjusted to 6, and 2 g of the intermediate product was added and mixed uniformly, stirred at 40° C. for 2 h, and centrifuged and washed to obtain a composite flame retardant;

[0039] The modified antioxidant is prepared by the following method:

[0040] Step B1: 22 g of catechol and 47.6 mL of 4-vinylaniline were mixed evenly, heated to 60° C., 0.71 g of anhydrous ferric chloride, 25 mL of deionized water and 10 mL of toluene were added and stirred, heated to 220° C. within 20 min, reacted for 5 h, cooled to 100° C., filtered while hot, and distilled under reduced pressure to obtain a pre-product;

[0041] Step B2: Disperse 3 g of N-phenylmaleimide and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 10 g of the pre-product and stir evenly. Under nitrogen protection, heat to 90 ° C and react for 4.5 hours. Distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain a modified antioxidant.

[0042] Embodiment 2: A method for preparing a flame retardant rubber-plastic thermal insulation material, comprising the following steps:

[0043] S1. Weigh the raw materials by weight: 62 parts of nitrile rubber, 32 parts of PVC resin, 12 parts of plasticizer, 5 parts of foaming agent, 3 parts of foaming aid, 25 parts of composite flame retardant (prepared by this embodiment), and 4 parts of modified anti-aging agent (prepared by this embodiment); put the nitrile rubber, PVC resin, trialkyl phosphate, composite flame retardant and modified anti-aging agent into a high-speed mixer, mix for 12 minutes, heat to 110° C., put into a low-speed mixer, cool to 40° C., discharge the material, and place it for 16 hours to obtain a pretreated material;

[0044] S2, adding azodicarbonamide and zinc oxide to the pretreated material, mixing for 7 minutes, discharging the material, and obtaining a mixed rubber;

[0045] S3, extrude the mixed rubber into a rubber extruder, the temperature of the extruder feeding section is 17°C, the temperature of the plasticizing section is 22°C, and the temperature of the die section is 27°C, and then transport it to the foaming furnace through the guide wheel, foam for 4 minutes, cool and cut, and obtain a flame-retardant rubber-plastic insulation material. The foaming furnace is divided into 7 temperature control zones, wherein the temperature of the first zone is 110°C, the second zone is 122°C, the third zone is 130°C, the fourth zone is 137°C, the fifth zone is 145°C, the sixth zone is 155°C, and the seventh zone is 165°C;

[0046] The composite flame retardant is prepared by the following method:

[0047] Step A1: 0.2 mol 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 50 mL N,N-dimethylformamide and 14.2 g dimethylallylamine were mixed, stirred at 150° C. for 9 h, filtered, washed, and dried under vacuum at 60° C. for 24 h to obtain a compound;

[0048] Step A2: 1.5 mol of the compound, 1.5 mol of 1-chlorohexane and 35 mL of methanol were mixed evenly, reacted for 12 h, cooled to room temperature, and dried under nitrogen protection to obtain an intermediate product;

[0049] Step A3: 11.65 g of cyclohexane hexanol phosphate was uniformly dispersed in 110 mL of deionized water, the pH was adjusted to 6, and 3 g of the intermediate product was added and mixed evenly, stirred at 40° C. for 2 h, and centrifuged and washed to obtain a composite flame retardant;

[0050] The modified antioxidant is prepared by the following method:

[0051] Step B1: 24 g of catechol and 49.75 mL of 4-vinylaniline were mixed evenly, heated to 65°C, and then 0.89 g of anhydrous ferric chloride, 32.5 mL of deionized water and 10 mL of toluene were added and stirred, and the temperature was raised to 220°C within 25 min, and the reaction was carried out for 5 h. When the temperature was lowered to 105°C, the mixture was filtered while hot and distilled under reduced pressure to obtain a pre-product;

[0052] Step B2: Disperse 4 g of N-phenylmaleimide and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 11 g of the pre-product and stir evenly. Under nitrogen protection, heat to 90 ° C and react for 4.5 hours. Distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain a modified antioxidant.

[0053] Embodiment 3: A method for preparing a flame retardant rubber-plastic thermal insulation material, comprising the following steps:

[0054] S1. Weigh the raw materials by weight: 75 parts of nitrile rubber, 45 parts of PVC resin, 15 parts of plasticizer, 10 parts of foaming agent, 5 parts of foaming aid, 40 parts of composite flame retardant (prepared by this embodiment), and 6 parts of modified anti-aging agent (prepared by this embodiment); put the nitrile rubber, PVC resin, trialkyl phosphate, composite flame retardant and modified anti-aging agent into a high-speed mixer, mix for 15 minutes, heat to 120° C., put into a low-speed mixer, cool to 50° C., discharge, and place for 24 hours to obtain a pretreated material;

[0055] S2, adding azodicarbonamide and zinc oxide to the pretreated material, mixing for 10 minutes, discharging the material, and obtaining a mixed rubber;

[0056] S3, extrude the mixed rubber into a rubber extruder, the temperature of the extruder feeding section is 20°C, the temperature of the plasticizing section is 25°C, and the temperature of the die section is 30°C, and then transported to a foaming furnace through a guide wheel, foamed for 5 minutes, cooled and cut, to obtain a flame-retardant rubber-plastic insulation material, the foaming furnace is divided into 7 temperature control zones, wherein the temperature of the first zone is 120°C, the second zone is 125°C, the third zone is 135°C, the fourth zone is 140°C, the fifth zone is 150°C, the sixth zone is 160°C, and the seventh zone is 170°C;

[0057] The composite flame retardant is prepared by the following method:

[0058] Step A1: 0.25 mol 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 60 mL N,N-dimethylformamide and 17.75 g dimethylallylamine were mixed, stirred at 150° C. for 9 h, filtered, washed, and dried under vacuum at 60° C. for 24 h to obtain a compound;

[0059] Step A2: 2 mol of the compound, 2 mol of 1-chlorohexane and 50 mL of methanol were mixed evenly, reacted for 12 h, cooled to room temperature, and dried under nitrogen protection to obtain an intermediate product;

[0060] Step A3: 12.1 g of cyclohexane hexanol phosphate was uniformly dispersed in 120 mL of deionized water, the pH was adjusted to 6, 4 g of the intermediate product was added and mixed evenly, stirred at 40° C. for 2 h, and centrifuged and washed to obtain a composite flame retardant;

[0061] The modified antioxidant is prepared by the following method:

[0062] Step B1: 26 g of catechol and 51.9 mL of 4-vinylaniline were mixed evenly, heated to 70°C, and then 1.07 g of anhydrous ferric chloride, 40 mL of deionized water and 10 mL of toluene were added and stirred, and the temperature was raised to 220°C within 30 min, and the reaction was carried out for 5 h. When the temperature was lowered to 110°C, the mixture was filtered while hot and distilled under reduced pressure to obtain a pre-product;

[0063] Step B2: Disperse 5 g of N-phenylmaleimide and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 12 g of the pre-product and stir evenly. Under nitrogen protection, heat to 90 ° C and react for 4.5 hours. Distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain a modified antioxidant.

[0064] Comparative Example 1: This comparative example is a flame retardant rubber-plastic thermal insulation material. The difference from Example 3 is that an equal amount of magnesium hydroxide is used to replace the composite flame retardant prepared in Example 3, and the rest is the same.

[0065] Comparative Example 2: This comparative example is a flame retardant rubber-plastic thermal insulation material. The difference from Example 3 is that an equal amount of 4,4'-thiobis(6-tert-butyl-3-methylphenol) is used to replace the modified antioxidant prepared in Example 3, and the rest are the same.

[0066] Performance test: The flame-retardant rubber-plastic thermal insulation materials prepared in Examples 1-3 and the comparative example were cut into standard test sizes, and the vertical combustion performance was tested using the GB / T2048-1996 plastic combustion performance test method; the samples were placed in a UV aging box at 60°C, 0.86w / cm2 , UV light exposure for 1000h, test the yellow index change difference, the larger the difference, the worse the anti-aging performance, hot air aging (100℃×24h) test the strength change rate and elongation change rate; the test results are shown in the following table:

[0067] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Vertical burning level V-1 V-1 V-1 V-2 V-1 Yellow index change difference 0.42 0.45 0.48 0.49 1.35 Strength change rate % 1 2 1 2 5 Elongation change% 2 1 2 2 5

[0068] It can be seen from the test data in the table that the flame retardant rubber-plastic thermal insulation material prepared by the present invention has excellent anti-aging effect. It can also be seen from the above table that the flame retardant rubber-plastic thermal insulation material prepared by the present invention has good flame retardancy and heat resistance.

[0069] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a flame retardant rubber-plastic thermal insulation material, characterized in that: The specific steps include: S1. Weigh the raw materials by weight: 50-75 parts of nitrile rubber, 20-45 parts of PVC resin, 10-15 parts of plasticizer, 1-10 parts of foaming agent, 1-5 parts of foaming aid, 10-40 parts of composite flame retardant, and 2-6 parts of modified anti-aging agent; put the nitrile rubber, PVC resin, plasticizer, composite flame retardant and modified anti-aging agent into a high-speed mixer, mix for 10-15 minutes, heat to 100-120° C., put into a low-speed mixer, cool to 30-50° C., discharge the materials, and place them for 8-24 hours to obtain a pretreated material; S2, adding the foaming agent and the foaming aid to the pretreated material, mixing for 4-10 minutes, discharging the material, and obtaining a mixed rubber; S3. Extrude the mixed rubber into a rubber extruder. The temperature of the extruder feeding section is 15-20°C, the temperature of the plasticizing section is 20-25°C, and the temperature of the die head section is 25-30°C. Then, the mixed rubber is transported to a foaming furnace through a guide wheel, foamed for 3-5 minutes, cooled and cut to obtain a flame-retardant rubber-plastic thermal insulation material. The foaming furnace is divided into 7 temperature control zones, wherein the temperature of the first zone is 100-120°C, the second zone is 120-125°C, the third zone is 125-135°C, the fourth zone is 135-140°C, the fifth zone is 140-150°C, the sixth zone is 150-160°C, and the seventh zone is 160-170°C.

2. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 1, characterized in that: The composite flame retardant is prepared by the following method: Step A1: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, N,N-dimethylformamide and dimethylallylamine were mixed, stirred at 150° C. for 9 h, filtered, washed, and dried under vacuum at 60° C. for 24 h to obtain a compound; Step A2: uniformly mix the compound, 1-chlorohexane and methanol, react for 12 hours, cool to room temperature, and dry under nitrogen protection to obtain an intermediate product; Step A3: Disperse cyclohexanehexol phosphate uniformly in deionized water, adjust the pH to 6, add the intermediate product and mix evenly, stir at 40° C. for 2 h, centrifuge and wash, and obtain a composite flame retardant.

3. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 2, characterized in that: In step A1, the usage ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, N,N-dimethylformamide and dimethylallylamine is 0.15-0.25 mol:40-60 mL:10.65-17.75 g.

4. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 2, characterized in that: In step A2, the usage ratio of the compound, 1-chlorohexane and methanol is 1-2 mol: 1-2 mol: 20-50 mL.

5. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 2, characterized in that: In step A3, the usage ratio of cyclohexanehexol phosphate, deionized water and intermediate product is 11.2-12.1 g: 100-120 mL: 2-4 g.

6. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 1, characterized in that: The modified antioxidant is prepared by the following method: Step B1: Evenly mix catechol and 4-vinylaniline, heat to 60-70°C, then add anhydrous ferric chloride, deionized water and toluene, stir, heat to 220°C within 20-30min, react for 5h, cool to 100-110°C, filter while hot, and distill under reduced pressure to obtain a pre-product; Step B2: Disperse N-phenylmaleimide and benzoyl peroxide evenly in xylene, add the pre-product and stir evenly, heat to 90°C under nitrogen protection for 4.5 hours, distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain a modified antioxidant.

7. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 6, characterized in that: In step B1, the dosage ratio of catechol, 4-vinylaniline, anhydrous ferric chloride, deionized water and toluene is 22-26 g: 47.6-51.9 mL: 0.71-1.07 g: 25-40 mL: 10 mL.

8. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 6, characterized in that: In step B2, the usage ratio of N-phenylmaleimide, benzoyl peroxide, xylene and pre-product is 3-5 g: 0.16 g: 70 mL: 10-12 g.

9. The method for preparing a flame retardant rubber-plastic thermal insulation material according to claim 1, characterized in that: The plasticizer is trialkyl phosphate, the foaming agent is azodicarbonamide, and the foaming aid is zinc oxide.

10. A flame retardant rubber-plastic thermal insulation material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.