Preparation method of flame-retardant and high-temperature resistant PVC material

Abstract

The invention relates to the field of material technology and discloses a method for preparing a flame-retardant and high-temperature resistant PVC material. The flame-retardant and high-temperature resistant PVC material comprises the following raw materials in parts by weight: a polyvinyl chloride resin, a stabilizer, a plasticizer, a carbonizing agent, a flame retardant and smoke suppressant, a lubricant, and an antioxidant. The carbonizing agent is prepared by amination-modifying cellulose and then compounding it with sodium stannate. The flame retardant and smoke suppressant is diatomaceous earth surface-modified with a phosphorus-containing flame retardant. The hydrogen bond effect between the carbonizing agent and the polyvinyl chloride molecular chain is utilized to form a hydrogen bond cross-linking network, thereby improving the high-temperature resistance and flame retardancy of the polyvinyl chloride, reducing the emission of toxic gases during combustion, reducing air pollution and harm to the human body, and contributing to promoting environmentally friendly and sustainable product design, and expanding the applicable fields of the polyvinyl chloride.

Description

Technical Field

[0001] The invention relates to the technical field of polyvinyl chloride composite materials, and in particular to a method for preparing a flame-retardant and high-temperature resistant PVC material. Background Art

[0002] Polyvinyl chloride (PVC) has good comprehensive properties such as acid and alkali resistance, electrical insulation, mechanical properties and processing properties. It is used everywhere in daily life and is one of the five most widely used general-purpose resins. Due to the high chlorine content in the PVC structure, it has good flame retardant properties. However, during the processing of PVC, a large amount of plasticizers are generally added to assist. The presence of these plasticizers greatly affects the flame retardant and high temperature resistance of PVC, making PVC products prone to combustion. In addition, a large amount of hydrogen chloride-containing smoke is released during the combustion process, which not only easily causes the fire to spread, but also causes potential property and safety hazards and environmental problems. These shortcomings have greatly limited the further development and application of PVC products. Therefore, flame retardant modification of PVC has great research value and safety benefits.

[0003] In the processing of polyvinyl chloride, adding inorganic flame retardants for flame retardant modification is a commonly used technical means. For example, the invention patent with application number CN201711220083.X discloses a silane cross-linked flame retardant polyvinyl chloride cable material and its preparation method. Antimony trioxide or molybdenum trioxide is selected as flame retardant a, and any one or a mixture of two or more of zinc borate, basic magnesium carbonate, silicon stannate, magnesium stannate and montmorillonite is selected as flame retardant b. Although the flame retardant modification of polyvinyl chloride can improve the flame retardant properties of polyvinyl chloride to a certain extent, these inorganic flame retardants have low flame retardant efficiency, resulting in a large amount of flame retardant added, causing the compatibility between the flame retardant and the matrix to deteriorate, thereby having a great impact on the mechanical properties of polyvinyl chloride products. According to test results, even if a large amount of inorganic flame retardant is added, the limiting oxygen index of the product is only 27-28%.

[0004] Based on this, the present invention provides a PVC material that combines the advantages of organic flame retardants and inorganic flame retardants to enable the PVC material to have excellent flame retardant and high temperature resistance. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a flame-retardant and high-temperature resistant PVC material, which solves the problem that the polyvinyl chloride material has poor flame retardancy and high-temperature resistance.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a flame-retardant and high-temperature resistant PVC material, comprising the following raw materials in parts by weight: 85-95 parts of polyvinyl chloride resin, 5-12 parts of stabilizer, 20-35 parts of plasticizer, 2-4.5 parts of charring agent, 4-8 parts of flame retardant and smoke suppressant, 0.5-1.5 parts of lubricant, and 0.1-0.4 parts of antioxidant;

[0008] The carbon-forming agent is prepared by modifying cellulose by amination and then compounding it with sodium stannate;

[0009] The flame retardant and smoke suppressant is diatomaceous earth with a phosphorus-containing flame retardant modified on its surface;

[0010] The preparation method of the flame retardant and high temperature resistant PVC material comprises the following steps:

[0011] Step 1: Pour parts by weight of polyvinyl chloride resin, stabilizer, plasticizer, carbonizing agent, lubricant and antioxidant into a mixer, set the mixer temperature to 120-130°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, continue stirring until a uniform material is formed to form a premix;

[0012] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 160-200°C to obtain a flame-retardant and high-temperature resistant PVC material.

[0013] Furthermore, the stabilizer is a calcium zinc stabilizer; the plasticizer is any one of the phthalates; the lubricant is any one of calcium stearate or liquid paraffin; and the antioxidant is any one of antioxidant 1010 or antioxidant 1076.

[0014] Furthermore, the preparation method of the carbon-forming agent comprises the following steps:

[0015] Step ①: Mix cellulose with sodium hydroxide solution, stir and alkalize at 0°C for 12-24 hours, then add it into ethanol and stir until a uniform dispersion is formed, add triethylbenzyl ammonium chloride and mix evenly, then add 2-chloroethylamine hydrochloride to the dispersion, stir at room temperature for 12-18 hours, filter out the solid material, and purify it to obtain aminated cellulose;

[0016] Step ②: Stir and disperse the aminated cellulose and purified water evenly to form a dispersion, add sodium stannate to the dispersion and mix evenly, stir at a temperature of 60-70° C. for 4-8 hours, cool and discharge, wash and freeze-dry to obtain a carbonizing agent.

[0017] Furthermore, in step ①, the average molecular weight of the cellulose is 25,000.

[0018] Furthermore, in step ①, the mass percentage concentration of the sodium hydroxide solution is 40-50%.

[0019] Furthermore, in step ②, the mass ratio of the aminated cellulose to sodium stannate is 1:2.4-3.

[0020] Through the above technical solution, the hydroxyl groups in the cellulose structure are alkalized by sodium hydroxide and can undergo a nucleophilic substitution reaction with the active chlorine in the 2-chloroethylamine hydrochloride structure under the action of triethylbenzyl ammonium chloride, thereby introducing active amino groups into the cellulose structure to prepare aminated cellulose. Since the amino groups are positively charged in aqueous solution, sodium stannate will ionize to negatively charged SnO3 in aqueous solution. 2- Through electrostatic action, they can combine with each other to produce a cellulose-based carbonizing agent.

[0021] Furthermore, the preparation method of the flame retardant and smoke suppressant comprises the following steps:

[0022] Step A: diatomaceous earth and 1,4-dioxane are mixed and dispersed evenly, and acryloyl chloride is added and mixed evenly, and nitrogen is passed through, and the mixture is stirred at 70-75° C. for 2-4 hours, and the solid material is separated by centrifugation to obtain a diatomaceous earth intermediate material;

[0023] Step B: Mix the diatomaceous earth intermediate material with toluene, perform ultrasonic dispersion, continue to add the phosphite compound and catalyst to the system, stir evenly, pass nitrogen to deoxygenate, stir at 65-70° C. for 6-12 hours, cool and discharge to obtain a flame retardant and smoke suppressant.

[0024] Furthermore, in step A, the average particle size of the diatomaceous earth is 4 μm.

[0025] Furthermore, in step B, the phosphite compound is any one of dimethyl phosphite, diethyl phosphite, diphenyl phosphite or dibenzyl phosphite.

[0026] Furthermore, in step B, the catalyst is azobisisobutyronitrile.

[0027] Through the above technical solution, the surface of diatomaceous earth contains abundant silanol groups, which can undergo an esterification reaction with the acyl chloride groups in the acryloyl chloride structure, thereby modifying the unsaturated alkenyl functional groups on the surface of the diatomaceous earth to produce a diatomaceous earth intermediate material. Under the action of the catalyst azobisisobutyronitrile, the unsaturated alkenyl functional groups can undergo an addition reaction with the PH bond in the structure of the phosphite compound, thereby modifying the phosphorus-containing flame retardant on the surface of the diatomaceous earth to produce a flame retardant and smoke suppressant.

[0028] Beneficial effects of the present invention:

[0029] (1) The carbonizing agent prepared by the present invention contains aminated cellulose in its structure. Since the aminated cellulose structure contains polyhydroxyl and polyamine groups, it can form hydrogen bonds with the polyvinyl chloride matrix, thereby enhancing the interaction force between the molecular chains and forming a polyvinyl chloride-cellulose three-dimensional network with a physical cross-linking structure, thereby increasing the cross-linking density of the polyvinyl chloride and thus improving the high-temperature resistance of the polyvinyl chloride material. At the same time, the oxygen-containing carbon ring in the cellulose structure is easy to form carbon during the combustion process and can act as a carbonizing agent. Moreover, the inorganic metal tin compound in the structure can react with the hydrogen chloride produced by the combustion of polyvinyl chloride to form tin chloride, thereby achieving the effect of suppressing the emission of toxic gases. In addition, after the inorganic metal tin compound is compounded with cellulose, its compatibility with the polyvinyl chloride matrix can be improved, thereby avoiding its negative impact on the mechanical properties of the polyvinyl chloride material.

[0030] (2) The present invention prepares a flame retardant and smoke suppressant as a filler for polyvinyl chloride materials. After the diatomaceous earth in the flame retardant and smoke suppressant is organically modified, an organic bonding layer is formed on the surface, which greatly improves the interfacial bonding between the diatomaceous earth and the polyvinyl chloride matrix and reduces the problem of decreased mechanical properties due to the addition of diatomaceous earth. At the same time, the organic bonding layer on the surface of the diatomaceous earth contains a phosphorus-containing flame retardant. When the polyvinyl chloride material burns, the phosphorus-containing flame retardant can cooperate with the carbonizing agent to quickly form a dense carbon layer on the surface of the polyvinyl chloride, thereby preventing the continuation of combustion and reducing the risk of fire spread. In addition, diatomaceous earth has a rich pore structure and can adsorb gaseous hydrogen chloride and solid carbon particles to prevent them from overflowing, thereby producing a smoke suppression effect, thereby effectively enhancing the flame retardant and smoke suppression properties of the polyvinyl chloride material.

[0031] (3) The present invention significantly improves the flame retardant and high temperature resistance of polyvinyl chloride by designing the formula of polyvinyl chloride, while reducing the emission of toxic gases during the combustion of polyvinyl chloride materials, reducing environmental pollution, and avoiding the harm of toxic gas emissions to the human body. It helps to promote environmentally friendly and sustainable engineering and product design and expand the applicable fields of the polyvinyl chloride material.

[0032] 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

[0033] The following will be combined with the embodiments to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In the following examples and comparative examples, the preparation method of the carbon-forming agent is as follows:

[0035] Step ①: 1.2 g of cellulose with an average molecular weight of 25,000 was mixed with 2 mL of a 50% by mass sodium hydroxide solution, stirred at 0°C for 16 hours, and then added to ethanol and stirred until a uniform dispersion was formed. 0.2 g of triethylbenzyl ammonium chloride was added and mixed evenly. 2 g of 2-chloroethylamine hydrochloride was then added to the dispersion. After the addition was complete, the mixture was stirred at room temperature for 16 hours, the solid material was filtered out, and purified to obtain aminated cellulose;

[0036] Step ②: 1 g of aminated cellulose was stirred and dispersed evenly with purified water to form a dispersion, 2.5 g of sodium stannate was added to the dispersion and mixed evenly, stirred at 65° C. for 6 h, cooled and discharged, and washed and freeze-dried to obtain a carbonizing agent.

[0037] The content of each element in the carbonizing agent was tested using an Escalab 250Xi X-ray photoelectron spectrometer. The test results showed that the carbon content was 49.12%, the nitrogen content was 2.59%, and the tin content was 13.61%.

[0038] In the following examples and comparative examples, the preparation method of the flame retardant and smoke suppressant is as follows:

[0039] Step A: 1.8 g of diatomaceous earth with an average particle size of 4 μm was mixed with 1,4-dioxane, and after uniform dispersion, 2.5 g of acryloyl chloride was added and mixed, and nitrogen was passed through, and the mixture was stirred at 70° C. for 3 h. The solid material was separated by centrifugation to obtain a diatomaceous earth intermediate material;

[0040] Weigh 0.4g of diatomaceous earth intermediate material as a sample, put it into 15mL of dichloromethane, ultrasonically disperse it evenly, and after forming a dispersion, add 30mL of Wei's solution to the dispersion, shake it well, let it stand for 30min, and continue to add 120mL of deionized water and 20mL of 15% potassium iodide solution to the dispersion. Use 0.1mol / L sodium thiosulfate standard solution to titrate until the color of the dispersion changes. Continue to add 2mL of 2% starch as an indicator to the dispersion. Continue titration until the color of the dispersion no longer changes. Record the volume of sodium thiosulfate standard solution used at this time X1, mL; do a blank control test, record the volume of sodium thiosulfate standard solution consumed X2, mL, through Calculate the molar number of carbon-carbon double bonds in the sample, where C is the concentration of the sodium thiosulfate standard solution, mol / L; M is the mass of the sample, g; after testing, W is 3.613 mmol / g;

[0041] Step B: 1.6 g of diatomaceous earth intermediate material was mixed with toluene, and ultrasonically dispersed. 1.5 g of dimethyl phosphite and 0.3 g of azobisisobutyronitrile were added to the system, and the mixture was stirred evenly. Nitrogen was passed through the mixture to deoxygenate the mixture. The mixture was stirred at 65° C. for 8 h, and the temperature was lowered and the material was discharged to obtain a flame retardant and smoke suppressant.

[0042] The same test method in step A was used to test the molar number of carbon-carbon double bonds in 0.4g of the flame retardant and smoke suppressant sample. The test showed that W was 0.784mmol / g. It was speculated that the reason for the reduction in carbon-carbon double bonds was that the carbon-carbon double bonds modified on the surface of the diatomaceous earth intermediate material reacted with the pH in the dimethyl phosphite structure to produce an addition reaction.

[0043] Example 1

[0044] A flame-retardant and high-temperature resistant PVC material, comprising the following raw materials in parts by weight: 85 parts of polyvinyl chloride resin, 5 parts of calcium zinc stabilizer, 20 parts of dioctyl phthalate, 2 parts of charring agent, 4 parts of flame retardant and smoke suppressant, 0.5 parts of calcium stearate, and 10100.1 parts of antioxidant;

[0045] The preparation method of the flame retardant and high temperature resistant PVC material comprises the following steps:

[0046] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, carbonizing agent, calcium stearate and antioxidant 1010 into a mixer, set the mixer temperature to 120°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, continue stirring until a uniform material is formed to form a premix;

[0047] Step 2: The premix is ​​transferred to a twin-screw extruder, melt-extruded and granulated at a temperature of 160° C. to obtain a flame-retardant and high-temperature resistant PVC material.

[0048] Example 2

[0049] A flame-retardant and high-temperature resistant PVC material, comprising the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 4 parts of charring agent, 6.5 parts of flame retardant and smoke suppressant, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0050] The preparation method of the flame retardant and high temperature resistant PVC material comprises the following steps:

[0051] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, carbonizing agent, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, and continue stirring until a uniform material is formed to form a premix;

[0052] Step 2: The premix is ​​transferred to a twin-screw extruder, melt-extruded and granulated at a temperature of 180° C. to obtain a flame-retardant and high-temperature resistant PVC material.

[0053] Example 3

[0054] A flame-retardant and high-temperature resistant PVC material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 12 parts of calcium zinc stabilizer, 35 parts of dioctyl phthalate, 4.5 parts of charring agent, 8 parts of flame retardant and smoke suppressant, 1.5 parts of calcium stearate, and 0.4 parts of antioxidant 1010;

[0055] The preparation method of the flame retardant and high temperature resistant PVC material comprises the following steps:

[0056] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, carbonizing agent, calcium stearate and antioxidant 1010 into a mixer, set the mixer temperature to 130°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, continue stirring until a uniform material is formed to form a premix;

[0057] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 200° C. to obtain a flame-retardant and high-temperature resistant PVC material.

[0058] Comparative Example 1

[0059] A PVC material comprises the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 4 parts of cellulose, 6.5 parts of flame retardant and smoke suppressant, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0060] The preparation method of the PVC material comprises the following steps:

[0061] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, cellulose, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, and continue stirring until a uniform material is formed to form a premix;

[0062] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 180° C. to obtain PVC material.

[0063] Comparative Example 2

[0064] A PVC material comprises the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 6.5 parts of flame retardant and smoke suppressant, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0065] The preparation method of the PVC material comprises the following steps:

[0066] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130°C, stir and mix evenly, add parts by weight of flame retardant and smoke suppressant, and continue stirring until a uniform material is formed to form a premix;

[0067] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 180° C. to obtain PVC material.

[0068] Comparative Example 3

[0069] A PVC material comprises the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 4 parts of carbonizing agent, 6.5 parts of diatomaceous earth, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0070] The preparation method of the PVC material comprises the following steps:

[0071] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, carbonizing agent, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130° C., stir and mix evenly, add parts by weight of diatomaceous earth, and continue stirring until a uniform material is formed to form a premix;

[0072] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 180° C. to obtain warm PVC material.

[0073] Comparative Example 4

[0074] A PVC material comprises the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 4 parts of carbonizing agent, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0075] The preparation method of the PVC material comprises the following steps:

[0076] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, carbonizing agent, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130° C., stir and mix evenly to form a premix;

[0077] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 180° C. to obtain PVC material.

[0078] Comparative Example 5

[0079] A PVC material comprises the following raw materials in parts by weight: 92 parts of polyvinyl chloride resin, 10 parts of calcium zinc stabilizer, 30 parts of dioctyl phthalate, 0.6 parts of liquid paraffin, and 0.2 parts of antioxidant 1076;

[0080] The preparation method of the PVC material comprises the following steps:

[0081] Step 1: Pour parts by weight of polyvinyl chloride resin, calcium zinc stabilizer, dioctyl phthalate, liquid paraffin and antioxidant 1076 into a mixer, set the mixer temperature to 130° C., stir and mix evenly to form a premix;

[0082] Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 180° C. to obtain PVC material.

[0083] The PVC materials prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention were made into test samples and the following performance tests were performed:

[0084] Refer to the national standard GB / T 2406.2-2009 to test the limiting oxygen index of the sample; refer to ISO 5660-1:2015 and set the radiation power to 50kW / m 2 , test the smoke release performance of the samples; weigh 0.5 mg of each sample and place it in a STA 7300 thermogravimetric-differential thermal analyzer under nitrogen protection. Set the heating rate to 10℃ / min and heat from room temperature to 800℃. Record the temperature T corresponding to 5% decomposition of the sample. 5wt％ , evaluate its high temperature resistance. Generally speaking, the higher the temperature, the better the high temperature resistance. The test results are shown in the table below:

[0085] Limiting oxygen index / % <![CDATA[Total smoke release amount / m 2 > <![CDATA[T 5wt％ / ℃]]> Example 1 33.5 12.2 285.4 Example 2 33.9 11.7 286.1 Example 3 33.8 11.8 285.5 Comparative Example 1 33.0 15.0 278.9 Comparative Example 2 31.3 16.4 267.1 Comparative Example 3 27.8 23.4 284.0 Comparative Example 4 27.2 26.5 283.5 Comparative Example 5 25.6 28.8 265.8

[0086] It can be seen from the test results in the above table that the PVC materials prepared in Examples 1 to 3 of the present invention have good flame retardancy, smoke suppression and high temperature resistance effects.

[0087] Comparative Example 1 uses unmodified cellulose as a carbonizing agent to prepare PVC material, so the smoke suppression effect is slightly poor. In addition, since the structure does not contain amino groups, the hydrogen bond content between the polyvinyl chloride molecular chain is small and the cross-linking density is low, resulting in poor high temperature resistance performance.

[0088] The PVC material prepared in Comparative Example 2 did not add a carbonizing agent, resulting in a slow surface carbonization rate during combustion, and therefore poor flame retardant and smoke suppression effects. At the same time, since the polyvinyl chloride molecular chain cannot form a cross-linked structure, the high temperature resistance surface is poor.

[0089] In Comparative Example 3, diatomaceous earth without surface modification was used as a flame retardant and smoke suppressant to prepare a PVC material. Therefore, the PVC material did not contain a phosphorus flame retardant, making it difficult to form an expanded carbon layer, resulting in a significant decrease in the flame retardant and smoke suppression effect.

[0090] The flame retardant and smoke suppressant was not used in the PVC material prepared in Comparative Example 4, so the flame retardant and smoke suppressant effect was further reduced.

[0091] The PVC material prepared in Comparative Example 5 does not contain a charring agent and a flame retardant and smoke suppressant, and therefore all of its properties are the worst.

[0092] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0093] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments 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 scope of protection of the present invention.

Claims

1. A method for preparing a flame retardant and high temperature resistant PVC material, characterized in that: The flame retardant and high temperature resistant PVC material comprises the following raw materials in parts by weight: 85-95 parts of polyvinyl chloride resin, 5-12 parts of stabilizer, 20-35 parts of plasticizer, 2-4.5 parts of carbonizing agent, 4-8 parts of flame retardant and smoke suppressant, 0.5-1.5 parts of lubricant, and 0.1-0.4 parts of antioxidant; The carbon-forming agent is prepared by modifying cellulose by amination and then compounding it with sodium stannate; The preparation method of the carbon-forming agent comprises the following steps: Step ①: Mix cellulose with sodium hydroxide solution, stir and alkalize at 0°C for 12-24 hours, then add it into ethanol and stir until a uniform dispersion is formed, add triethylbenzyl ammonium chloride and mix evenly, then add 2-chloroethylamine hydrochloride to the dispersion, stir at room temperature for 12-18 hours, filter out the solid material, and purify it to obtain aminated cellulose; Step ②: stirring and dispersing the aminated cellulose and purified water to form a dispersion, adding sodium stannate to the dispersion, stirring at a temperature of 60-70° C. for 4-8 hours, cooling and discharging, washing and freeze-drying to obtain a carbonizing agent; The flame retardant and smoke suppressant is diatomaceous earth with a phosphorus-containing flame retardant modified on its surface; The preparation method of the flame retardant and smoke suppressant comprises the following steps: Step A: diatomaceous earth and 1,4-dioxane are mixed and dispersed evenly, and acryloyl chloride is added and mixed evenly, and nitrogen is passed through, and the mixture is stirred at 70-75° C. for 2-4 hours, and the solid material is separated by centrifugation to obtain a diatomaceous earth intermediate material; Step B: Mix the diatomaceous earth intermediate material with toluene, disperse it by ultrasonication, continue to add the phosphite compound and the catalyst to the system, stir evenly, pass nitrogen to deoxygenate, stir at a temperature of 65-70°C for 6-12 hours, cool and discharge the material to obtain a flame retardant and smoke suppressant; The preparation method of the flame retardant and high temperature resistant PVC material comprises the following steps: Step 1: Pour the above-mentioned parts by weight of polyvinyl chloride resin, stabilizer, plasticizer, carbonizing agent, lubricant and antioxidant into a mixer, set the mixer temperature to 120-130°C, stir and mix evenly, add the above-mentioned parts by weight of flame retardant and smoke suppressant, continue stirring until a uniform material is formed to form a premix; Step 2: Transfer the premix to a twin-screw extruder, melt-extrude and granulate at a temperature of 160-200°C to obtain a flame-retardant and high-temperature resistant PVC material.

2. The method for preparing a flame retardant and high temperature resistant PVC material according to claim 1, characterized in that: The stabilizer is a calcium zinc stabilizer; the plasticizer is any one of the phthalates; the lubricant is any one of calcium stearate or liquid paraffin; and the antioxidant is any one of antioxidant 1010 or antioxidant 1076.

3. The method for preparing a flame retardant and high temperature resistant PVC material according to claim 1, characterized in that: In step ①, the average molecular weight of the cellulose is 25,000.

4. The method for preparing a flame-retardant and high-temperature resistant PVC material according to claim 1, characterized in that: In step ①, the mass percentage concentration of the sodium hydroxide solution is 40-50%.

5. The method for preparing a flame retardant and high temperature resistant PVC material according to claim 1, characterized in that: In step ②, the mass ratio of the aminated cellulose to sodium stannate is 1:2.4-3.

6. The method for preparing a flame-retardant and high-temperature resistant PVC material according to claim 1, characterized in that: In step A, the average particle size of the diatomaceous earth is 4 μm.

7. The method for preparing a flame-retardant and high-temperature resistant PVC material according to claim 1, characterized in that: In step B, the phosphite compound is any one of dimethyl phosphite, diethyl phosphite, diphenyl phosphite or dibenzyl phosphite.

8. The method for preparing a flame-retardant and high-temperature resistant PVC material according to claim 1, characterized in that: In step B, the catalyst is azobisisobutyronitrile.