High-temperature-resistant flame-retardant material and preparation method thereof

Abstract

The application belongs to the technical field of flame-retardant materials, and particularly relates to a high-temperature-resistant flame-retardant material and a preparation method thereof. The high-temperature-resistant flame-retardant material is composed of the following components in parts by mass: ethylene-vinyl acetate copolymer 50-60 parts, ethylene-propylene-diene rubber 10-20 parts, maleic anhydride grafted ethylene-vinyl acetate 2-5 parts, flame retardant 20-25 parts, graphene 1-2 parts, citrate plasticizer 5-8 parts, calcium stearate 0.5-1 part, paraffin 1-2 parts, antioxidant 0.5-1 part, and sensitized crosslinking agent 1-3 parts. The flame retardant is prepared by mixing phosphorus-modified nanocellulose, modified zinc borate and melamine. The high-temperature-resistant flame-retardant material prepared by the application has good flame-retardant effect, and has good tensile strength, elongation at break, good processability and other properties.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, specifically relating to a high-temperature resistant flame retardant material and its preparation method. Background Technology

[0002] Heat-shrinkable materials, also known as polymer shape memory materials, are intelligent materials that combine polymer materials with radiation processing technology. Ordinary polymer materials such as polyethylene and polyvinyl chloride are usually linear structures. After being irradiated by radiation sources such as electron accelerators, they become network structures. These materials then possess a unique "memory effect," meaning that materials that expand when heated and solidify when cooled can shrink back to their original shape upon heating. They can be applied in industries such as electronics, home appliances, communications, power, automobiles, and pipeline corrosion protection.

[0003] Most flame-retardant heat-shrinkable materials use halogenated flame retardants. For example, Chinese patent application CN110144077A discloses a polyolefin heat-shrinkable marking sleeve and its preparation method. The formula uses a compound product of decabromodiphenyl ethane and antimony trioxide as a flame retardant. Although it has a certain flame-retardant effect, bromine-based flame retardants release toxic hydrogen bromide gas when burning and may produce harmful substances that affect human health.

[0004] To avoid the aforementioned problems, researchers have added halogen-free flame retardants, mainly magnesium hydroxide and aluminum hydroxide, to flame-retardant heat-shrinkable materials. For example, Chinese patent application CN105273296A discloses a polyolefin heat-shrinkable tube for busbar insulation and its preparation method. This technical solution uses magnesium hydroxide and microcapsule red phosphorus as flame retardants. Although it does not contain halogen-containing flame retardants, the amount of magnesium hydroxide in the formula is relatively large. The addition of a large amount of inorganic filler can easily disrupt the continuity of the polyolefin matrix, resulting in a significant increase in material hardness and a decrease in flexibility and elasticity. This affects indicators such as tensile strength and elongation at break, thus impacting the reliability of the product under complex working conditions. Summary of the Invention

[0005] Existing flame retardant materials suffer from the problem of requiring a large amount of halogen-free flame retardant, which affects product performance. To address this issue, this invention provides a high-temperature resistant flame retardant material and its preparation method.

[0006] To achieve the objectives of this invention, the following technical solution is adopted:

[0007] This invention provides a high-temperature resistant flame-retardant material, composed of the following components in parts by weight:

[0008] 50-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of ethylene propylene diene monomer (EPDM) rubber, 2-5 parts of maleic anhydride-grafted ethylene-vinyl acetate, 20-25 parts of flame retardant, 1-2 parts of graphene, 5-8 parts of citrate ester plasticizer, 0.5-1 part of calcium stearate, 1-2 parts of paraffin wax, 0.5-1 part of antioxidant, and 1-3 parts of sensitizing crosslinking agent;

[0009] The flame retardant is prepared by mixing phosphorus-modified nanocellulose, modified zinc borate, and melamine.

[0010] By adopting the above technical solutions, ethylene-vinyl acetate copolymer and EPDM rubber complement each other, providing properties such as flexibility and impact resistance. Vinyl acetate groups can form hydrogen bonds with phosphorus-modified nanocellulose, improving interfacial bonding and enhancing the elasticity of the blend system. Phosphorus-modified nanocellulose is compounded with modified zinc borate and melamine, while graphene acts as a nanoframework to enhance the strength of the carbon layer, forming a phosphorus-nitrogen-boron-graphene synergistic flame retardant system. Calcium stearate and paraffin wax form a composite lubricant, which is compounded with maleic anhydride-grafted ethylene-vinyl acetate to maintain good processing fluidity. The synergistic effect of multiple components improves the flame retardant efficiency, mechanical properties, and processing adaptability of the material.

[0011] Preferably, the mass ratio of phosphorus-modified nanocellulose, modified zinc borate, and melamine is (3-5):(1-2):1.

[0012] By adopting the above technical solution, phosphorus-modified nanocellulose and modified zinc borate form a composite network, with melamine uniformly dispersed within it. At high temperature, phosphide is catalyzed to form carbon, creating a carbon layer framework. B2O3 generated from the decomposition of zinc borate fills the pores of the carbon layer, improving its density. The gas generated from the decomposition of melamine causes the carbon layer to expand, forming a heat-insulating structure. However, excessive use of phosphorus-modified nanocellulose can lead to excessively rigid materials. When the amount of melamine is too low, the carbon layer expansion effect is poor, while excessive use can easily compete with phosphorus-modified nanocellulose for matrix compatibility.

[0013] Preferably, the preparation method of the P-NC includes the following steps:

[0014] (1a) Mix nanocellulose and dimethyl sulfoxide evenly, disperse by ultrasonication, add triethylamine under anaerobic conditions and mix evenly to obtain mixture 1;

[0015] (1b) Add phosphorus oxychloride dropwise to mixture 1 and mix well. After the addition is complete, heat the mixture to react, centrifuge, wash, and dry to obtain phosphorus-modified nanocellulose.

[0016] By adopting the above technical solution, phosphorus is introduced into nanocellulose. At high temperature, phosphorus can be converted into polyphosphoric acid, which catalyzes the dehydration of matrix resins such as ethylene-vinyl acetate copolymer into carbon, thereby increasing the carbon layer residue. The rigid skeleton of nanocellulose supports the carbon layer structure, inhibits crack propagation, and forms a continuous and dense heat insulation layer. It is halogen-free, releases no toxic gases during combustion, and reduces smoke density.

[0017] Preferably, the mass ratio of nanocellulose to phosphorus oxychloride is 1:(2-3); and the mass ratio of triethylamine to phosphorus oxychloride is (1.8-2.2):1.

[0018] By adopting the above technical solution, excessive phosphorus oxychloride can easily lead to a loose char layer structure, while insufficient phosphorus oxychloride cannot form a continuous char layer and is prone to melting and dripping during combustion. Excessive triethylamine is difficult to completely remove by washing and is prone to residue. When triethylamine is insufficient, phosphorus oxychloride is prone to hydrolysis, consuming the effective phosphorus source and reducing the phosphorus loading rate.

[0019] Preferably, in step (1b), the temperature of the droplet is 0-5℃; the reaction temperature is 60-70℃; and the reaction time is 12-20h.

[0020] By adopting the above technical solution, adding phosphorus oxychloride dropwise at a lower temperature can reduce the hydrolysis rate of POCl3 and avoid violent reactions.

[0021] Preferably, the preparation method of modified zinc borate includes the following steps:

[0022] (2a) Mix zinc borate, anhydrous ethanol and water evenly to obtain mixture 2;

[0023] (2b) Mix the aluminate coupling agent with anhydrous ethanol to obtain mixture 3;

[0024] (2c) Mix mixture 2 and mixture 3 evenly, heat to react, filter, wash, and dry to obtain modified zinc borate.

[0025] By adopting the above technical solution, the aluminate coupling agent can bond to the surface of zinc borate, reducing the agglomeration of zinc borate, while the long carbon chain group can entangle or crosslink with the resin, reducing the interfacial tension between the resin and other components such as ethylene-vinyl acetate copolymer.

[0026] Preferably, the amount of aluminate coupling agent used is 1%-3% of the mass of zinc borate.

[0027] By adopting the above technical solutions, insufficient use of aluminate coupling agent and insufficient surface hydroxyl coverage can easily lead to zinc borate agglomeration; excessive use of aluminate coupling agent will form multilayer physical adsorption and weaken the interfacial bonding force.

[0028] Preferably, in step (2c), the reaction temperature is 45-55℃ and the reaction time is 2-4h.

[0029] By adopting the above technical solution, the coupling agent and zinc borate can be efficiently bonded at the specified reaction temperature and time.

[0030] Preferably, the citrate plasticizer is selected from either tributyl citrate or acetylated tributyl citrate.

[0031] By adopting the above technical solution, the ester groups of citrate plasticizers can form hydrogen bonds with the vinyl acetate groups in ethylene-vinyl acetate copolymers and the hydroxyl groups in phosphorus-modified nanocellulose, etc., and are uniformly dispersed in the matrix, which can avoid flame retardant agglomeration caused by plasticizer migration.

[0032] Secondly, the present invention also provides a method for preparing the above-mentioned high-temperature resistant flame-retardant material, comprising the following steps:

[0033] (S1) Ethylene-vinyl acetate copolymer, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride-grafted ethylene-vinyl acetate, flame retardant, graphene, citrate plasticizer, calcium stearate, paraffin wax, antioxidant and sensitizing crosslinking agent are mixed and then mixed evenly in an internal mixer at 110-120℃ to obtain a compound.

[0034] (S2) The compound is extruded and granulated in a single screw extruder at 120-140℃ to obtain granules;

[0035] (S3) The granules are extruded in a screw extruder at 120-140℃ to obtain pipes;

[0036] (S4) Irradiate the pipe to crosslink it. The irradiation dose is 6-10 Mrad. The crosslinked pipe expands 1-4 times at a temperature of 120-150℃ to obtain a high-temperature flame-retardant material.

[0037] By adopting the above technical solutions, the mixing and extrusion processes ensure component dispersion and structural uniformity, with a wide extrusion temperature range and high process stability. Irradiation can cause cross-linking reactions in polymer chains to form a three-dimensional network structure, which can inhibit the thermal decomposition of the polymer matrix and the release of flammable gases, and slow down the combustion rate. At the same time, the cross-linking process enhances the intermolecular forces, thereby improving tensile strength and impact resistance.

[0038] In summary, the beneficial effects of this invention are:

[0039] (1) This invention uses ethylene-vinyl acetate copolymer and ethylene propylene diene monomer rubber as base materials, combined with maleic anhydride grafted ethylene-vinyl acetate compatibilizer, and forms a flame retardant by compounding phosphorus-modified nanocellulose and modified zinc borate and adding melamine, and adds antioxidants, composite lubricants and other related additives to make a high temperature resistant flame retardant material, which has good flame retardant effect and processing fluidity and other properties;

[0040] (2) The phosphorus-modified nanocellulose prepared in this invention forms a three-dimensional network skeleton in the matrix, supports the carbon layer structure, forms a continuous and dense heat insulation layer, improves the tensile strength of the material, and can also form hydrogen bonds with the vinyl acetate unit of the ethylene-vinyl acetate copolymer to improve interfacial compatibility.

[0041] (3) In this invention, the surface of zinc borate is modified by an aluminate coupling agent. The aluminate groups on the modified zinc borate surface can form hydrogen bonds with the amino groups of melamine, promoting the uniform distribution of melamine on the surface of zinc borate. At high temperature, the gas generated by the decomposition of melamine is wrapped by zinc borate to form an expanded foam carbon layer, which enhances the heat insulation effect. Detailed Implementation

[0042] The technical solution of the present invention will be explained in detail below with reference to several representative embodiments.

[0043] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples and comparative examples are commercially available.

[0044] The antioxidant used in the following examples and comparative examples is antioxidant 1010, the sensitizing crosslinking agent is pentaerythritol tetraacrylate, and the aluminate coupling agent is aluminate coupling agent DL-411.

[0045] Preparation Example 1

[0046] The specific preparation steps of the phosphorus-modified nanocellulose in this preparation example are as follows:

[0047] (1a) Add 10g of nanocellulose to 200mL of dimethyl sulfoxide and disperse by ultrasonication for 45min; introduce nitrogen into the device, purge the air, add 45g of triethylamine and stir for 15min to obtain mixture 1;

[0048] (1b) 25g of phosphorus oxychloride was slowly added dropwise to mixture 1 at a temperature of 5°C. After the addition was complete, the ice bath was removed and the temperature was raised to 70°C for 18h. The system was placed in an ice bath and anhydrous ethanol was slowly added to quench the reaction. The mixture was centrifuged and the precipitate was washed 5 times with deionized water and acetone alternately. The precipitate was then placed in a vacuum drying oven and dried at 60°C for 24h to obtain phosphorus-modified nanocellulose.

[0049] Preparation Example 2

[0050] The specific preparation steps of the phosphorus-modified nanocellulose in this preparation example are as follows:

[0051] (1a) Add 10g of nanocellulose to 200mL of dimethyl sulfoxide and disperse by ultrasonication for 45min; introduce nitrogen into the device, purge the air, add 44g of triethylamine and stir for 15min to obtain mixture 1;

[0052] (1b) 20g of phosphorus oxychloride was slowly added dropwise to mixture 1 at a temperature of 3°C. After the addition was complete, the ice bath was removed and the temperature was raised to 65°C for 12h. The system was placed in an ice bath and anhydrous ethanol was slowly added to quench the reaction. The mixture was centrifuged and the precipitate was washed 5 times with deionized water and acetone alternately. The precipitate was then dried in a vacuum drying oven at 60°C for 24h to obtain phosphorus-modified nanocellulose.

[0053] Preparation Example 3

[0054] The specific preparation steps of the phosphorus-modified nanocellulose in this preparation example are as follows:

[0055] (1a) Add 10g of nanocellulose to 200mL of dimethyl sulfoxide and disperse by ultrasonication for 45min; introduce nitrogen into the device, purge the air, add 60g of triethylamine and stir for 15min to obtain mixture 1;

[0056] (1b) 30g of phosphorus oxychloride was slowly added dropwise to mixture 1 at a temperature of 0°C. After the addition was complete, the ice bath was removed and the temperature was raised to 68°C for 20h. The system was placed in an ice bath and anhydrous ethanol was slowly added to quench the reaction. The mixture was centrifuged and the precipitate was washed 5 times with deionized water and acetone alternately. The precipitate was then placed in a vacuum drying oven and dried at 60°C for 24h to obtain phosphorus-modified nanocellulose.

[0057] Preparation Example 4

[0058] The preparation method of this example of modified zinc borate includes the following specific steps:

[0059] (2a) Disperse 100g zinc borate, 30mL anhydrous ethanol and 400mL water by ultrasonication for 45min to obtain mixture 2;

[0060] (2b) Disperse 1g of aluminate coupling agent with 50mL of anhydrous ethanol by ultrasonication for 30min to obtain mixture 3;

[0061] (2c) Add mixture 3 to mixture 2 and stir for 15 min. Heat to 45℃ and react for 4 h. Filter, wash 3 times alternately with water and anhydrous ethanol, and dry in a vacuum drying oven at 70℃ for 24 h to obtain modified zinc borate.

[0062] Preparation Example 5

[0063] The preparation method of this example of modified zinc borate includes the following specific steps:

[0064] (2a) Disperse 100g zinc borate, 30mL anhydrous ethanol and 400mL water by ultrasonication for 45min to obtain mixture 2;

[0065] (2b) Disperse 3g of aluminate coupling agent with 50mL of anhydrous ethanol by ultrasonication for 30min to obtain mixture 3;

[0066] (2c) Add mixture 3 to mixture 2 and stir for 15 min. Heat to 55℃ and react for 2 h. Filter, wash 3 times alternately with water and anhydrous ethanol, and dry in a vacuum drying oven at 70℃ for 24 h to obtain modified zinc borate.

[0067] Example 1

[0068] This embodiment of a high-temperature resistant flame-retardant material is composed of the following components by mass:

[0069] 5 kg of ethylene-vinyl acetate copolymer, 2 kg of ethylene propylene diene monomer (EPDM) rubber, 0.3 kg of maleic anhydride-grafted ethylene-vinyl acetate, 2.4 kg of flame retardant, 0.2 kg of graphene, 0.8 kg of tributyl citrate, 0.07 kg of calcium stearate, 0.2 kg of paraffin wax, 0.05 kg of antioxidant, and 0.2 kg of sensitizing crosslinking agent;

[0070] The flame retardant was prepared by mixing 1.5 kg of phosphorus-modified nanocellulose prepared in Preparation Example 1, 0.6 kg of modified zinc borate prepared in Preparation Example 5, and 0.3 kg of melamine.

[0071] The specific steps of the preparation method of the high-temperature resistant flame-retardant material in this embodiment are as follows:

[0072] (S1) Ethylene-vinyl acetate copolymer, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride-grafted ethylene-vinyl acetate, flame retardant, graphene, citrate plasticizer, calcium stearate, paraffin wax, antioxidant and sensitizing crosslinking agent are mixed and then kneaded evenly in an internal mixer at 120°C to obtain a compound.

[0073] (S2) The compound is extruded and granulated in a single screw extruder at 125°C to obtain granules;

[0074] (S3) The granules are extruded in a screw extruder at 125°C to obtain pipes;

[0075] (S4) The pipe is cross-linked by irradiation with an irradiation dose of 6Mrad. The cross-linked pipe expands 3 times at 140℃ to obtain a high-temperature resistant flame-retardant material.

[0076] Example 2

[0077] This embodiment of a high-temperature resistant flame-retardant material is composed of the following components by mass:

[0078] 6 kg of ethylene-vinyl acetate copolymer, 1 kg of ethylene propylene diene monomer (EPDM) rubber, 0.2 kg of maleic anhydride-grafted ethylene-vinyl acetate, 2.5 kg of flame retardant, 0.15 kg of graphene, 0.5 kg of tributyl acetylacetic acid, 0.05 kg of calcium stearate, 0.1 kg of paraffin wax, 0.08 kg of antioxidant, and 0.3 kg of sensitizing crosslinking agent;

[0079] The flame retardant was prepared by mixing 1.5 kg of phosphorus-modified nanocellulose prepared in Preparation Example 1, 0.5 kg of modified zinc borate prepared in Preparation Example 5, and 0.5 kg of melamine.

[0080] The specific steps of the preparation method of the high-temperature resistant flame-retardant material in this embodiment are as follows:

[0081] (S1) Ethylene-vinyl acetate copolymer, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride-grafted ethylene-vinyl acetate, flame retardant, graphene, citrate plasticizer, calcium stearate, paraffin wax, antioxidant and sensitizing crosslinking agent are mixed and then kneaded evenly in an internal mixer at 110°C to obtain a compound.

[0082] (S2) The compound is extruded and granulated in a single screw extruder at 140°C to obtain granules;

[0083] (S3) The granules are extruded in a screw extruder at 140°C to obtain pipes;

[0084] (S4) The pipe is cross-linked by irradiation with an irradiation dose of 10Mrad. The cross-linked pipe expands by 1 time at 120°C to obtain a high-temperature resistant flame-retardant material.

[0085] Example 3

[0086] This embodiment of a high-temperature resistant flame-retardant material is composed of the following components by mass:

[0087] 5.5 kg of ethylene-vinyl acetate copolymer, 1.5 kg of ethylene propylene diene monomer (EPDM) rubber, 0.5 kg of maleic anhydride-grafted ethylene-vinyl acetate, 2.1 kg of flame retardant, 0.1 kg of graphene, 0.7 kg of tributyl acetylacetic acid, 0.1 kg of calcium stearate, 0.15 kg of paraffin wax, 0.1 kg of antioxidant, and 0.1 kg of sensitizing crosslinking agent;

[0088] The flame retardant was prepared by mixing 1.2 kg of phosphorus-modified nanocellulose prepared in Preparation Example 1, 0.6 kg of modified zinc borate prepared in Preparation Example 5, and 0.3 kg of melamine.

[0089] The specific steps of the preparation method of the high-temperature resistant flame-retardant material in this embodiment are as follows:

[0090] (S1) Ethylene-vinyl acetate copolymer, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride-grafted ethylene-vinyl acetate, flame retardant, graphene, citrate plasticizer, calcium stearate, paraffin wax, antioxidant and sensitizing crosslinking agent are mixed and then kneaded evenly in an internal mixer at 115°C to obtain a compound.

[0091] (S2) The compound is extruded and granulated in a single screw extruder at 130°C to obtain granules;

[0092] (S3) The granules are extruded in a screw extruder at 130°C to obtain pipes;

[0093] (S4) The pipe is cross-linked by irradiation with an irradiation dose of 8Mrad. The cross-linked pipe expands 4 times at 150°C to obtain a high-temperature resistant flame-retardant material.

[0094] Comparative Example 1

[0095] The difference from Example 1 is that the ratio of phosphorus-modified nanocellulose, modified zinc borate and melamine in the flame retardant was adjusted in Comparative Example 1, including four groups a-d. The specific dosage is shown in Table 1. All other aspects are the same as in Example 1.

[0096] Table 1 Flame retardant ratio

[0097]

[0098] Comparative Example 2

[0099] The difference from Example 1 is that this comparative example uses an equal amount of nanocellulose instead of phosphorus-modified nanocellulose, while the rest is the same as in Example 1.

[0100] Comparative Example 3

[0101] The difference from Example 1 is that this comparative example uses an equal amount of zinc borate instead of modified zinc borate, while the rest is the same as in Example 1.

[0102] Comparative Example 4

[0103] The difference from Example 1 is that the calcium stearate content in this comparative example is 0.13 kg and the paraffin content is 0.02 kg, while the rest are the same as in Example 1.

[0104] Comparative Example 5

[0105] The difference from Example 1 is that no graphene is added in this comparative example, but everything else is the same as in Example 1.

[0106] Comparative Example 6

[0107] This comparative example of a high-temperature resistant flame-retardant material is composed of the following components by mass, all others being the same as in Example 1:

[0108] 8 kg of ethylene-vinyl acetate copolymer, 3 kg of ethylene propylene diene monomer (EPDM) rubber, 0.3 kg of maleic anhydride-grafted ethylene-vinyl acetate, 0.8 kg of flame retardant, 0.5 kg of graphene, 0.8 kg of tributyl citrate, 0.07 kg of calcium stearate, 0.2 kg of paraffin wax, 0.05 kg of antioxidant, and 0.2 kg of sensitizing crosslinking agent;

[0109] The flame retardant was prepared by mixing 0.25 kg of phosphorus-modified nanocellulose prepared in Preparation Example 1, 0.1 kg of modified zinc borate prepared in Preparation Example 5, and 0.05 kg of melamine.

[0110] Related performance tests

[0111] The high-temperature resistant flame-retardant materials prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to relevant performance tests, and the test results are shown in Table 2.

[0112] Table 2 Test Results

[0113]

[0114] As can be seen from the test results in Table 2, the high-temperature resistant flame-retardant materials prepared in Examples 1-3 of this invention have good flame-retardant effects and good tensile strength and elongation at break.

[0115] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A high temperature resistant flame retardant material, characterized in that, It is composed of the following components by mass parts: Ethylene-vinyl acetate copolymer 50-60 parts, ethylene-propylene-diene rubber 10-20 parts, maleic anhydride grafted ethylene-vinyl acetate 2-5 parts, flame retardant 20-25 parts, graphene 1-2 parts, citrate plasticizer 5-8 parts, calcium stearate 0.5-1 part, paraffin wax 1-2 parts, antioxidant 0.5-1 part, sensitized crosslinking agent 1-3 parts; The flame retardant is prepared by mixing phosphorus modified nanocellulose, modified zinc borate and melamine, and the mass ratio of phosphorus modified nanocellulose, modified zinc borate and melamine is (3-5):(1-2):1; The preparation method of the modified zinc borate comprises the following steps: (2a) uniformly mix zinc borate, anhydrous ethanol and water to obtain a mixed solution 2; (2b) uniformly mix aluminic ester coupling agent and anhydrous ethanol to obtain a mixed solution 3; (2c) uniformly mix the mixed solution 2 and the mixed solution 3, heat and react, filter, wash and dry to obtain the modified zinc borate.

2. A high temperature resistant flame retardant material as claimed in claim 1, wherein, The preparation method of the phosphorus modified nanocellulose comprises the following steps: (1a) uniformly mix nanocellulose and dimethyl sulfoxide, ultrasonic dispersion, add triethylamine under anaerobic condition and uniformly mix to obtain a mixed solution 1; (1b) drop phosphorus oxychloride into the mixed solution 1 and uniformly mix, after the dropping is completed, heat and react, centrifugal, wash, dry to obtain the phosphorus modified nanocellulose.

3. A high temperature resistant flame retardant material as claimed in claim 2, wherein, The mass ratio of the nanocellulose and phosphorus oxychloride is 1:(2-3); the mass ratio of triethylamine and phosphorus oxychloride is (1.8-2.2):

1.

4. The high temperature resistant flame retardant material according to claim 2, wherein, In the step (1b), the dropping temperature is 0-5℃; the reaction temperature is 60-70℃, and the reaction time is 12-20h.

5. The high temperature resistant flame retardant material according to claim 1, wherein, The amount of the aluminic ester coupling agent is 1%-3% of the mass of the zinc borate.

6. The high temperature resistant flame retardant material according to claim 1, wherein, In the step (2c), the reaction temperature is 45-55℃, and the reaction time is 2-4h.

7. The high temperature resistant flame retardant material according to claim 1, wherein, The citrate plasticizer is selected from one of tributyl citrate or acetyl tributyl citrate.

8. A method of producing a high temperature resistant flame retardant material as claimed in any one of claims 1 to 7, wherein, Comprise the following steps: (S1) mix ethylene-vinyl acetate copolymer, ethylene-propylene-diene rubber, maleic anhydride grafted ethylene-vinyl acetate, flame retardant, graphene, citrate plasticizer, calcium stearate, paraffin wax, antioxidant and sensitized crosslinking agent, and uniformly mix them in a banbury mixer at 110-120℃ to obtain a mixed material; (S2) extrude and granulate the mixed material in a single screw extruder at 120-140℃ to obtain a granular material; (S3) extrude the granular material in a screw extruder at 120-140℃ to obtain a pipe material; (S4) irradiate and crosslink the pipe material, the irradiation dose is 6-10Mrad, and the pipe material after radiation crosslinking is expanded by 1-4 times at a temperature of 120-150℃ to obtain a high-temperature resistant flame retardant material.

Images