Flame-retardant modified composite rubber and plastic material and preparation method thereof

Abstract

The invention relates to the technical field of materials, and discloses a flame-retardant modified composite rubber-plastic material and a preparation method thereof, and the rubber-plastic material takes nitrile rubber and polyvinyl chloride as base materials. The flame-retardant rubber-plastic composite material is prepared through a vulcanization foaming process by taking a rubber-plastic composite material as a main material, an intumescent flame retardant, a modified bentonite additive and the like as auxiliary materials, the intumescent flame retardant can quickly form an intumescent carbon layer during combustion of the rubber-plastic material, the purpose of greatly improving the flame retardance of the rubber-plastic composite material can be achieved by adding a small amount, and the defect that a large amount of traditional inorganic flame retardants need to be added is overcome; and the problem that the flame retardant property of the material is difficult to last due to migration and precipitation of a conventional micromolecular flame retardant can be effectively avoided. The modified soil moistening additive is prepared by organically modifying bentonite by using polyphenyl ether, and the polyphenyl ether is used as an organic transition layer, so that the interfacial compatibility of the bentonite with nitrile rubber and polyvinyl chloride can be improved, and the mechanical properties such as compressive strength of the material can be improved.

Description

Technical Field

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

[0002] With the rapid development of global industrialization, the requirements for material performance are becoming increasingly stringent. Traditional single materials can no longer meet the complex and ever-changing engineering needs, and material compounding has become an effective way to solve this problem. Rubber-plastic composite materials, as an organic combination of rubber and plastic, not only inherit the high elasticity and wear resistance of rubber, but also integrate the advantages of plastic such as easy processing and chemical corrosion resistance, becoming a research hotspot in the field of materials science and a focus of industrial applications. Rubber-plastic composite foam materials are made by adding a foaming agent and foaming the rubber-plastic composite material. This foam material has a rich pore structure and has multiple functions such as sound insulation, shock absorption, and heat insulation. Therefore, it has been widely studied in recent years.

[0003] Nitrile-butadiene rubber (NBR) has excellent comprehensive properties and contains polar groups in its structure, which makes it compatible with polymer materials such as polyvinyl chloride (PVC). Therefore, using NBR and polyvinyl chloride as the base materials for rubber-plastic composite materials can complement each other's strengths and produce rubber-plastic composite materials with excellent comprehensive properties. However, the flame retardant properties of foamed rubber-plastic composite materials are poor, making them flammable. Moreover, when burned, molten drips are produced, causing the fire to spread, which is very disadvantageous in the current situation where high fire resistance requirements are placed on materials. In addition, the mechanical strength of foamed materials is also poor, making it difficult to meet industry requirements. Based on this, the present invention provides a composite rubber-plastic material with good mechanical properties and flame retardant properties, which can solve the problems existing in the prior art. Summary of the Invention

[0004] In order to solve the problems mentioned in the background technology, the purpose of the present invention is to provide a flame retardant modified composite rubber-plastic material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A flame retardant modified composite rubber-plastic material, characterized by comprising the following raw materials in parts by weight: 60-75 parts of nitrile rubber; 20-30 parts of polyvinyl chloride; 2-6.5 parts of intumescent flame retardant; 1-4 parts of modified bentonite additive; 2-4 parts of vulcanizing agent; 1-3 parts of accelerator; 0.5-1.5 parts of antioxidant; 4-8 parts of foaming agent; 15-25 parts of chlorinated paraffin oil; 10-15 parts of plasticizer; 1-3 parts of lubricant.

[0006] As a further embodiment of the present invention, the preparation method of the intumescent flame retardant is as follows: Step S1, adding maltose to ethanol, heating to 50-60° C., stirring until a uniform mixture is formed, then adding 2-chloropyrazine-2-carboxylic acid and a composite catalyst to the mixture, stirring evenly, stirring at 50-60° C. for 4-8 hours, stopping heating, and filtering the product to obtain a maltose derivative; Step S2: add the maltose derivative to toluene, stir and mix, then continue to add the phosphate derivative and the acid binding agent. After the addition is completed, raise the temperature to 80-90°C, keep stirring at this temperature for 6-9 hours, stop heating, cool and discharge the material to obtain the intumescent flame retardant.

[0007] As a further embodiment of the present invention, in step S1, the composite catalyst is a mixture of dicyclohexylcarbodiimide and 4-dimethylaminopyridine, with a mass ratio of 1:0.2-0.4.

[0008] As a further embodiment of the present invention, in step S2, the phosphate derivative is any one of dibutyl phosphite, dimethyl phosphite, diethyl phosphite or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0009] As a further embodiment of the present invention, in step S2, the acid binding agent is triethylamine.

[0010] In the above technical solution, first, under the action of a composite catalyst, the hydroxyl group in the maltose structure can undergo a condensation reaction with the active carboxyl substituent in the 2-chloropyrazine-2-carboxylic acid structure to produce a maltose derivative. Then, under the action of an acid-binding agent, the halogen substituent on the pyridine ring can further react with the pH in the phosphate derivative structure, thereby connecting the maltose and the phosphate derivative by using 2-chloropyrazine-2-carboxylic acid as a linker. Maltose has a cyclic structure and can act as a carbon-forming agent. The pyridine ring can provide nitrogen as a gas source, and phosphorus can act as an acid source, which meets the characteristics of a ternary intumescent flame retardant.

[0011] As a further embodiment of the present invention, the preparation method of the modified bentonite additive is as follows: Step SS1: adding the hydroxy-terminated polyphenylene ether to xylene and mechanically stirring the mixture to form a uniform mixed solution; then adding 2,3-epoxypropyltrimethylammonium chloride and boron trifluoride etherate complex to the mixed solution; after the addition is completed, the temperature is raised to 60-70° C., and the mixture is stirred at this temperature for 6-8 hours, and then the heating is stopped, the temperature is lowered, and the material is discharged to obtain a cationic modified polyphenylene ether; Step S22: add sodium bentonite and cationic modified polyphenylene ether to a 60-70% volume fraction ethanol aqueous solution, stir and mix, turn on heating, raise the temperature to 60-70°C, keep stirring for 1-3 hours, stop heating, cool and discharge the material to obtain the modified bentonite additive.

[0012] As a further embodiment of the present invention, in step SS1, the number average molecular weight of the hydroxy-terminated polyphenylene ether is 5000.

[0013] As a further embodiment of the present invention, in step SS2, the mass ratio of the sodium bentonite to the cationic modified polyphenylene ether is 1:0.2-0.3.

[0014] In the above technical solution, first, under the catalytic action of boron trifluoride ether complex, the terminal hydroxyl group in the terminal hydroxyl polyphenyl ether structure can undergo a ring-opening reaction with the epoxy group in the 2,3-epoxypropyltrimethylammonium chloride structure, thereby preparing a polyphenyl ether derivative containing quaternary ammonium cations in the structure, that is, a cationic modified polyphenyl ether. Then, the sodium bentonite is organically modified by an ion exchange method to prepare a modified bentonite additive.

[0015] As a further embodiment of the present invention, the vulcanizing agent is sulfur; the antioxidant is antioxidant MB, antioxidant 4020 or antioxidant RD; the foaming agent is azodicarbonamide; the plasticizer is dioctyl phthalate; and the lubricant is polyethylene wax or paraffin.

[0016] A method for preparing a flame retardant modified composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, modified bentonite additive, antioxidant, chlorinated paraffin oil, plasticizer and lubricant into an internal mixer, mix for 10-20 minutes, and then perform rubber removal at a temperature of 160-180°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent, accelerator and foaming agent with the rubber compound, continue to mix for 5-10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber compound is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0017] Beneficial effects of the present invention: (1) The present invention prepares a ternary intumescent flame retardant to perform flame retardant modification on the rubber-plastic composite material. By utilizing the mechanism that the intumescent flame retardant can quickly form an intumescent carbon layer during combustion, the flame retardant properties of the rubber-plastic composite material can be greatly improved by adding a small amount of the intumescent flame retardant. This avoids the defect that traditional inorganic flame retardants need to be added in large quantities, and can also effectively avoid the migration and precipitation of conventional small molecule flame retardants, which makes it difficult to maintain the flame retardant properties of the material.

[0018] (2) The present invention uses polyphenylene ether to organically modify bentonite. On the one hand, polyphenylene ether can be used as an organic transition layer to improve the interfacial compatibility between bentonite and nitrile rubber and polyvinyl chloride. On the other hand, the rigid structure of polyphenylene ether can be used to cooperate with inorganic bentonite to improve the compressive strength and other mechanical properties of the material.

[0019] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Example 1

[0022] A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 60 parts of nitrile rubber; 20 parts of polyvinyl chloride; 2 parts of intumescent flame retardant; 1 part of modified bentonite additive; 2 parts of sulfur as a vulcanizing agent; 1 part of accelerator DM; 0.5 parts of antioxidant MB; 4 parts of azodicarbonamide, a blowing agent; 15 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 10 parts; 1 part of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, modified bentonite additive, antioxidant MB, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 10 minutes, and then perform rubber removal at a temperature of 160°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator DM and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 5 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0023] Example 2

[0024] A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 65 parts of nitrile rubber; 25 parts of polyvinyl chloride; 6 parts of intumescent flame retardant; 3 parts of modified bentonite additive; 3 parts of sulfur as a vulcanizing agent; 2 parts of accelerator MBT; 1 part of antioxidant MB; 5 parts of azodicarbonamide, a foaming agent; 20 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 12 parts; 2 parts of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, modified bentonite additive, antioxidant MB, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 15 minutes, and then perform glue removal at a temperature of 170°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator MBT and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0025] Example 3

[0026] A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 75 parts of nitrile rubber; 30 parts of polyvinyl chloride; 6.5 parts of intumescent flame retardant; 4 parts of modified bentonite additive; 4 parts of sulfur as a vulcanizing agent; 3 parts of accelerator MBT; 1.5 parts of antioxidant RD; 8 parts of azodicarbonamide, a foaming agent; 25 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 15 parts; 3 parts of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to their weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, modified bentonite additive, antioxidant RD, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 20 minutes, and then perform rubber removal at a temperature of 180°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator MBT and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 1402℃, 15.±2℃, 160±2℃. After completion, it is cooled by air cooling.

[0027] Comparative Example 1 A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 65 parts of nitrile rubber; 25 parts of polyvinyl chloride; 3 parts of modified bentonite additive; 3 parts of sulfur as a vulcanizing agent; 2 parts of accelerator MBT; 1 part of antioxidant MB; 5 parts of azodicarbonamide, a foaming agent; 20 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 12 parts; 2 parts of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to the weight ratio, first add nitrile rubber, polyvinyl chloride, modified bentonite additive, antioxidant MB, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 15 minutes, and then perform rubber removal at a temperature of 170°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator MBT and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0028] Comparative Example 2 A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 65 parts of nitrile rubber; 25 parts of polyvinyl chloride; 6 parts of intumescent flame retardant; 3 parts of sodium bentonite; 3 parts of sulfur as a vulcanizing agent; 2 parts of accelerator MBT; 1 part of antioxidant MB; 5 parts of azodicarbonamide, a foaming agent; 20 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 12 parts; 2 parts of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to their weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, sodium bentonite, antioxidant MB, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 15 minutes, and then perform rubber removal at a temperature of 170°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator MBT and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0029] Comparative Example 3 A flame retardant modified composite rubber-plastic material, comprising the following raw materials in parts by weight: 65 parts of nitrile rubber; 25 parts of polyvinyl chloride; 6 parts of intumescent flame retardant; 3 parts of sulfur as a vulcanizing agent; 2 parts of accelerator MBT; 1 part of antioxidant MB; 5 parts of azodicarbonamide, a foaming agent; 20 parts of chlorinated paraffin oil; Plasticizer dioctyl phthalate 12 parts; 2 parts of lubricant polyethylene wax; The preparation method of the composite rubber-plastic material comprises the following steps: The first step is to prepare all the raw materials according to weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, antioxidant MB, chlorinated paraffin oil, plasticizer dioctyl phthalate and lubricant polyethylene wax into an internal mixer, mix for 15 minutes, and then perform rubber removal at a temperature of 170°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent sulfur, accelerator MBT and foaming agent azodicarbonamide with the mixed rubber, continue mixing for 10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber material is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

[0030] The intumescent flame retardants in the above examples and comparative examples were prepared by the following method: Step S1, adding 2.4 g of maltose to ethanol, heating to 55° C., stirring until a uniform mixture is formed, then adding 0.5 g of 2-chloropyrazine-2-carboxylic acid, 0.2 g of dicyclohexylcarbodiimide and 0.05 g of 4-dimethylaminopyridine to the mixture, stirring evenly, stirring at 55° C. for 6 h, stopping heating, and filtering the product to obtain a maltose derivative; Step S2: add 1.8 g of maltose derivative to toluene, stir and mix, then add 0.4 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and triethylamine. After the addition is completed, raise the temperature to 85° C., keep stirring at this temperature for 8 hours, stop heating, cool and discharge the material, and the intumescent flame retardant can be obtained.

[0031] The modified bentonite additives in the above examples and comparative examples were prepared by the following method: Step SS1, adding 1.2 g of a hydroxy-terminated polyphenylene ether having a number average molecular weight of 5000 to xylene, mechanically stirring to form a uniform mixed solution, and then adding 0.08 g of 2,3-epoxypropyltrimethylammonium chloride and 0.01 g of boron trifluoride ether complex to the mixed solution. After the addition is completed, the temperature is raised to 65° C., and the mixture is stirred at this temperature for 8 hours. Then, the heating is stopped, the temperature is lowered, and the material is discharged to obtain a cationic modified polyphenylene ether; Step S22, add 1.5g of sodium bentonite and 0.4g of cationic modified polyphenylene ether to a 70% volume fraction ethanol aqueous solution, stir and mix, turn on the heating, raise the temperature to 65°C, keep stirring for 2h, stop heating, cool and discharge the material to obtain the modified bentonite additive.

[0032] Performance Testing The rubber and plastic materials in the examples and comparative examples were made into test specimens that met the specifications and various performance tests were performed; Conduct flame retardant performance test according to standard GB / T 2406.2-2009; Conduct compression resistance test according to standard GB / T 8813-2020; The test results are shown in the table below:

[0033] Test results show that rubber and plastic materials containing intumescent flame retardants exhibit significantly superior flame retardancy. Using unmodified bentonite as an additive, compatibility issues prevent the full utilization of bentonite's advantages as an inorganic reinforcing agent. Furthermore, polyphenylene ether cannot enhance the rigidity of the rubber and plastic material, resulting in reduced mechanical properties. However, bentonite's layered chain structure provides a certain degree of insulation against oxygen and heat, thus positively impacting the flame retardancy of rubber and plastic materials.

Claims

1. A flame retardant modified composite rubber-plastic material, characterized in that: According to parts by weight, the following raw materials are included: 60-75 parts of nitrile rubber; 20-30 parts of polyvinyl chloride; 2-6.5 parts of intumescent flame retardant; 1-4 parts of modified bentonite additive; 2-4 parts of vulcanizing agent; 1-3 parts of accelerator; 0.5-1.5 parts of antioxidant; 4-8 parts of foaming agent; 15-25 parts of chlorinated paraffin oil; 10-15 parts of plasticizer; 1-3 parts of lubricant.

2. The flame retardant modified composite rubber-plastic material according to claim 1, characterized in that: The preparation method of the intumescent flame retardant is as follows: Step S1, adding maltose to ethanol, heating to 50-60° C., stirring until a uniform mixture is formed, then adding 2-chloropyrazine-2-carboxylic acid and a composite catalyst to the mixture, stirring evenly, stirring at 50-60° C. for 4-8 hours, stopping heating, and filtering the product to obtain a maltose derivative; Step S2: add the maltose derivative to toluene, stir and mix, then continue to add the phosphate derivative and the acid binding agent. After the addition is completed, raise the temperature to 80-90°C, keep stirring at this temperature for 6-9 hours, stop heating, cool and discharge the material to obtain the intumescent flame retardant.

3. The flame retardant modified composite rubber-plastic material according to claim 2, characterized in that: In step S1, the composite catalyst is a mixture of dicyclohexylcarbodiimide and 4-dimethylaminopyridine in a mass ratio of 1:0.2-0.

4.

4. The flame retardant modified composite rubber-plastic material according to claim 2, characterized in that: In step S2, the phosphate derivative is any one of dibutyl phosphite, dimethyl phosphite, diethyl phosphite or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

5. The flame retardant modified composite rubber-plastic material according to claim 2, characterized in that: In step S2, the acid binding agent is triethylamine.

6. The flame retardant modified composite rubber-plastic material according to claim 1, characterized in that: The preparation method of the modified bentonite additive is as follows: Step SS1: adding the hydroxy-terminated polyphenylene ether to xylene and mechanically stirring the mixture to form a uniform mixed solution; then adding 2,3-epoxypropyltrimethylammonium chloride and boron trifluoride etherate complex to the mixed solution; after the addition is completed, the temperature is raised to 60-70° C., and the mixture is stirred at this temperature for 6-8 hours, and then the heating is stopped, the temperature is lowered, and the material is discharged to obtain a cationic modified polyphenylene ether; Step S22: add sodium bentonite and cationic modified polyphenylene ether to a 60-70% volume fraction ethanol aqueous solution, stir and mix, turn on heating, raise the temperature to 60-70°C, keep stirring for 1-3 hours, stop heating, cool and discharge the material to obtain the modified bentonite additive.

7. The flame retardant modified composite rubber-plastic material according to claim 6, characterized in that: In step SS1, the number average molecular weight of the hydroxy-terminated polyphenylene ether is 5000.

8. The flame retardant modified composite rubber-plastic material according to claim 6, characterized in that: In step SS2, the mass ratio of the sodium bentonite to the cationic modified polyphenylene ether is 1:0.2-0.

3.

9. The flame retardant modified composite rubber-plastic material according to claim 1, characterized in that: The vulcanizing agent is sulfur; the accelerator is accelerator MBT or accelerator DM; the antioxidant is antioxidant MB, antioxidant 4020 or antioxidant RD; the foaming agent is azodicarbonamide; the plasticizer is dioctyl phthalate; and the lubricant is polyethylene wax or paraffin.

10. A method for preparing the flame retardant modified composite rubber-plastic material according to claim 1, characterized in that: The following steps are involved: The first step is to prepare all the raw materials according to weight, first add nitrile rubber, polyvinyl chloride, intumescent flame retardant, modified bentonite additive, antioxidant, chlorinated paraffin oil, plasticizer and lubricant into an internal mixer, mix for 10-20 minutes, and then perform rubber removal at a temperature of 160-180°C. After refining and slicing, a rubber mixture is formed; The second step is to mix the vulcanizing agent, accelerator and foaming agent with the rubber compound, continue to mix for 5-10 minutes, discharge the material, feed it into the extruder, and carry out the extrusion process. Finally, the obtained rubber compound is transferred to the oven for vulcanization and foaming. The foaming process passes through seven temperature control zones, and the temperatures of each zone are: zone 1 120±2℃, 125±2℃, 130±2℃, 140±2℃, 150±2℃, 160±2℃. After the end, it is cooled by air cooling.

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