High-flame-retardant PVC composite material for PU coating and preparation method thereof

Abstract

The application discloses PVC composite material for high-flame-retardant coated PU and a preparation method thereof, and belongs to the technical field of polymer materials. The composite material provided by the application is prepared from the following raw materials in parts by weight: polyvinyl chloride resin, chlorinated polyvinyl chloride resin, dioctyl terephthalate, stabilizer, magnesium hydroxide, zinc borate, antimony trioxide, lubricant, modified activated carbon and nano lanthanum oxide. The preparation method comprises the following steps: preliminarily mixing the magnesium hydroxide, zinc borate and antimony trioxide, adding the polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide, mixing to obtain a premix; adding the remaining raw materials into the premix, mixing to obtain a mixture; and feeding the mixture into a double-screw extruder to perform melt blending, extruding, cooling, pulling, cutting and obtaining the PVC composite material. The composite material prepared by the application has excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

Description

Technical Field

[0001] This application belongs to the field of polymer materials technology, specifically relating to a high flame-retardant PVC composite material for PU coating and its preparation method. Background Technology

[0002] With the continuous improvement of modern welding technology and industrial automation, electric welding machines are widely used in manufacturing, construction engineering, and many other fields. As an important component of electric welding machines, the gas hose plays a crucial role in conveying gas during the welding process. Therefore, the materials used for the gas hose not only need to have good flexibility and mechanical strength, but also must be able to maintain excellent flame retardancy, corrosion resistance, and wear resistance in high-temperature and complex gas environments.

[0003] Currently, most welding machine hoses use an inner layer of PU material and an outer layer of PVC material. Polyvinyl chloride (PVC) is widely used in the manufacture of flexible pipes such as hoses due to its low cost, excellent processing performance, and certain flexibility. However, conventional PVC material is easily combustible under high temperatures or open flame conditions, releasing large amounts of black toxic fumes, posing a significant safety hazard. Furthermore, PVC material has weak resistance to acidic, alkaline, and oily environments during long-term use, making it susceptible to chemical corrosion, leading to material performance degradation and consequently affecting its service life.

[0004] To improve the overall performance of PVC materials, existing technologies typically modify them by adding flame retardants, plasticizers, and other functional additives. However, existing flame retardants often require high dosages to achieve a certain flame-retardant effect, which not only increases material costs but may also adversely affect the material's mechanical properties, such as reducing its flexibility and tensile strength. Furthermore, these traditional flame-retardant systems are difficult to effectively suppress the black toxic smoke produced during combustion in practical applications.

[0005] Therefore, there is an urgent need to develop a PVC composite material with excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect, which can overcome the defects of existing technologies and meet the performance requirements of industrial fields for gas pipe materials used in electric welding machines. Summary of the Invention

[0006] In view of this, this application provides a PVC composite material for high flame retardant PU coating and a method for preparing the same. The PVC composite material provided by this application has excellent flame retardancy, corrosion resistance, abrasion resistance, and smoke suppression effect.

[0007] In a first aspect, this application provides a PVC composite material for high flame retardant PU coating, which, by weight, comprises: 40-60 parts of polyvinyl chloride resin, 40-60 parts of chlorinated polyvinyl chloride resin, 60-80 parts of dioctyl terephthalate, 3-8 parts of stabilizer, 30-50 parts of magnesium hydroxide, 4-8 parts of zinc borate, 4-8 parts of antimony trioxide, 0.5-1 part of lubricant, 5-10 parts of modified activated carbon, and 0.5-2 parts of nano-lanthanum oxide.

[0008] By adopting the above technical solution and using specific raw materials, this application achieves excellent flame retardancy, smoke suppression, corrosion resistance, and abrasion resistance in PVC composite materials. This application uses polyvinyl chloride and chlorinated polyvinyl chloride (CPVC) as the matrix resin, which not only provides good processing performance and mechanical strength, but also enhances the material's heat aging resistance and flame retardancy due to the chlorine element introduced into CPVC. Dioctyl terephthalate (DOTP) is used as a plasticizer, which improves flexibility while ensuring good flowability, facilitating subsequent extrusion molding.

[0009] In this application, magnesium hydroxide is the main halogen-free environmentally friendly flame retardant. Upon thermal decomposition, it absorbs heat and releases water vapor, effectively reducing the combustion temperature, diluting toxic fumes, and inhibiting flame spread, thereby reducing smoke generation. Zinc borate works synergistically with magnesium hydroxide to further promote char layer formation and improve the barrier effect at the combustion interface. Antimony trioxide combines with chlorine-containing components (such as CPVC) to capture free radicals in the gas phase, enhancing flame retardant efficiency. The combined effect of these three flame retardant systems gives the material excellent flame retardancy.

[0010] The modified activated carbon of this application can release metal oxides (such as CuO) at high temperatures, further catalyzing the formation of carbon and enhancing its flame-retardant effect. Combined with the use of nano-lanthanum oxide, it can significantly improve the material's oxidation resistance and thermal stability, while synergistically enhancing flame retardancy and smoke suppression properties. Nano-lanthanum oxide can form a dense protective film on the material surface, further enhancing its chemical stability, and together with the modified activated carbon, improves the material's corrosion resistance and wear resistance.

[0011] Optionally, by weight, the raw material composition includes: 50 parts polyvinyl chloride resin, 50 parts chlorinated polyvinyl chloride resin, 70 parts dioctyl terephthalate, 5 parts stabilizer, 40 parts magnesium hydroxide, 6 parts zinc borate, 6 parts antimony trioxide, 0.8 parts lubricant, 8 parts modified activated carbon, and 1 part nano lanthanum oxide.

[0012] By adopting the above technical solution, this application can further improve the flame retardancy, corrosion resistance, wear resistance and smoke suppression effect of composite materials by controlling the raw material composition of the composite materials.

[0013] Optionally, the stabilizer includes at least one of bisphenol A phosphite, dibutyltin dilaurate, and methyltin mercaptan.

[0014] By adopting the above technical solution, the stabilizer of this application can play a key role in thermal stabilization and anti-oxidation, and can effectively inhibit the chain degradation reaction caused by dehydrochlorination (HCl) of PVC resin during high-temperature processing, thereby preventing the material from discoloration, embrittlement or decline in mechanical properties.

[0015] Optionally, the weight ratio of the magnesium hydroxide, the zinc borate, and the antimony trioxide is 6-8:1-2:1-2.

[0016] By adopting the above technical solution, the specific weight ratio of magnesium hydroxide, zinc borate, and antimony trioxide in the flame-retardant system of this application enables multiple flame-retardant mechanisms to work synergistically, significantly improving the flame retardancy of the material, reducing smoke density, and enhancing smoke suppression. The addition of zinc borate and antimony trioxide also enhances the material's oxidation resistance and resistance to chemical corrosion to a certain extent. The above weight ratio not only achieves excellent flame retardancy and low smoke emission but also takes into account good corrosion resistance and wear resistance.

[0017] Optionally, the lubricant includes at least one of pentaerythritol stearate, oxidized polyethylene wax, and silicone oil.

[0018] By adopting the above technical solution, the lubricant of this application can improve processing fluidity and reduce internal and external friction, thereby enhancing the processing performance and surface finish of the material during extrusion molding. This not only helps improve production efficiency but also optimizes surface quality and long-term stability without sacrificing the material's mechanical properties.

[0019] Optionally, the modified activated carbon has an average particle size of 75 μm to 150 μm.

[0020] By adopting the above technical solution, this application controls the average particle size of the modified activated carbon, which helps it to be evenly distributed in the matrix resin and fully exert its adsorption and catalytic carbonization functions, thereby effectively suppressing the release of combustible gases and reducing smoke generation during combustion. Simultaneously, the metal oxides loaded on the surface of the modified activated carbon with this particle size can synergistically enhance the thermal stability and flame retardant efficiency of the material, further improving its flame retardancy. Furthermore, this particle size range can effectively fill the microporous structure in the PVC matrix, improving the material's density and surface hardness, thereby improving its wear resistance; while the presence of metal oxides also enhances the material's chemical stability in acidic and alkaline environments, improving its overall corrosion resistance.

[0021] Optionally, the weight ratio of the modified activated carbon to the nano-lanthanum oxide is 6 to 12:1.

[0022] By adopting the above technical solution, this application controls the weight ratio of modified activated carbon to nano-lanthanum oxide, which can effectively reduce smoke generation during combustion, reduce the emission of toxic gases, and significantly improve the flame retardancy of the material. Furthermore, the modified activated carbon and nano-lanthanum oxide work together to form a double-layer protective film on the material surface, which not only improves the density and hardness of the material but also maintains good surface smoothness, thereby enhancing the material's corrosion resistance and wear resistance.

[0023] Secondly, this application provides a method for preparing the above-mentioned high flame-retardant PVC composite material for PU coating, including the following steps:

[0024] Step S1: The magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then the polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added. The mixture is stirred at 400 rpm to 600 rpm for 5 min to 10 min at a temperature of 60 ℃ to 80 ℃ to obtain a premix.

[0025] Step S2: Add the dioctyl terephthalate, the stabilizer, and the lubricant to the premix, and mix at a stirring speed of 800 rpm to 1200 rpm for 5 min to 10 min at a temperature of 80℃ to 100℃ to obtain the mixture.

[0026] Step S3: The mixture is fed into a twin-screw extruder for melt blending at a temperature of 140℃~180℃ and a screw speed of 100rpm~300rpm. The mixture is then extruded, cooled, drawn, and cut to obtain a PVC composite material for high flame retardant PU coating.

[0027] By adopting the above technical solution, the preparation method provided in this application ensures that each component is uniformly dispersed in the matrix resin through staged mixing and control of process parameters, and gives full play to their synergistic effect, thereby obtaining a composite material with excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0028] Optionally, the modified activated carbon is prepared by:

[0029] Step 1: Soak activated carbon in copper nitrate solution and let it stand at room temperature for 6 to 24 hours; the solid-liquid ratio of activated carbon to copper nitrate solution is 1:(10 to 20), and the concentration of copper nitrate solution is 0.5 mol / L;

[0030] Step 2: Remove the soaked activated carbon and dry it.

[0031] Step 3: Place the dried activated carbon into a muffle furnace and calcine it at a rate of 5℃ / min to 10℃ / min to 400℃ to 600℃ in an air atmosphere for 2 hours to 4 hours.

[0032] Step 4: Cool the calcined activated carbon naturally to room temperature in a muffle furnace, sieve it, and obtain the modified activated carbon.

[0033] By adopting the above technical solution, the preparation method of modified activated carbon in this application ensures that the metal salt fully penetrates into the micropores and mesopores of the activated carbon in step one, achieving a high loading efficiency and laying the foundation for the formation of highly dispersed CuO nanoparticles during subsequent calcination. The calcination in step three effectively guarantees the formation of CuO and enhances its bonding force with the activated carbon matrix, preventing it from detaching during subsequent processing or use. Furthermore, the natural cooling method after calcination helps reduce the damage of thermal stress to the material structure, maintaining the original porous structure and high specific surface area characteristics of the activated carbon.

[0034] In the modified activated carbon prepared in this application, CuO nanoparticles promote the formation of a carbon layer during combustion, isolate heat and oxygen transfer, and adsorb harmful gases and fine particles, significantly reducing smoke production and helping to improve the flame retardant and smoke-suppressing functions of the material. The modified activated carbon can form a protective film on its surface to resist acid and alkali corrosion, improve the density of the material, and thus improve the corrosion resistance and wear resistance of the material.

[0035] Optionally, in step two, the drying process includes: air-drying the activated carbon naturally at room temperature for 4 to 8 hours, and then placing it in an oven and drying it at 80°C to 120°C for 8 to 12 hours.

[0036] By adopting the above technical solution, this application employs a two-stage drying process. The room temperature air-drying stage effectively removes free water adsorbed on the surface of activated carbon and some volatile liquids in the pores, reducing energy consumption in the subsequent heating and drying process and avoiding particle bursting or structural damage caused by sudden evaporation of moisture. The oven drying stage further removes deep-seated moisture and some organic impurities remaining in the microporous structure, ensuring that the material reaches a high degree of dryness before entering the high-temperature calcination process, thereby ensuring that it can generate highly dispersed CuO nanoparticles as expected during the subsequent calcination process.

[0037] In summary, the present invention has at least one of the following beneficial technical effects:

[0038] 1. The PVC composite material provided in this application has excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0039] 2. The modified activated carbon and nano-lanthanum oxide in this application work together to synergistically enhance the flame retardancy and smoke suppression properties of the material. They also form a double-layer protective film on the material surface, increasing the material's density and hardness, thereby improving its corrosion resistance and wear resistance.

[0040] 3. The preparation method provided in this application ensures that each component is uniformly dispersed in the matrix resin through staged mixing and control of process parameters, and gives full play to their synergistic effect, thereby obtaining a composite material with excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0042] The inventors of this application discovered in their research on high flame-retardant PVC materials that: existing PVC materials are flammable and release black toxic fumes; in addition, their corrosion resistance and abrasion resistance cannot meet the performance requirements of industrial applications for gas pipe materials used in welding machine operations.

[0043] To address the aforementioned issues, this application proposes a high flame-retardant PVC composite material for coating PU. By weight, its raw material composition includes: 40-60 parts of polyvinyl chloride resin, 40-60 parts of chlorinated polyvinyl chloride resin, 60-80 parts of dioctyl terephthalate, 3-8 parts of stabilizer, 30-50 parts of magnesium hydroxide, 4-8 parts of zinc borate, 4-8 parts of antimony trioxide, 0.5-1 part of lubricant, 5-10 parts of modified activated carbon, and 0.5-2 parts of nano-lanthanum oxide.

[0044] This application also proposes a method for preparing the above-mentioned high flame retardant coated PU PVC composite material, including the following steps: Step S1, magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added, and the mixture is mixed at a stirring speed of 400 rpm to 600 rpm for 5 min to 10 min at a temperature of 60℃ to 80℃ to obtain a premix.

[0045] Step S2: Add dioctyl terephthalate, stabilizer and lubricant to the premix, mix at a stirring speed of 800 rpm to 1200 rpm for 5 min to 10 min, and at a temperature of 80℃ to 100℃ to obtain the mixture.

[0046] Step S3: The mixture is fed into a twin-screw extruder for melt blending at a temperature of 140℃~180℃ and a screw speed of 100rpm~300rpm. The mixture is then extruded, cooled, drawn, and cut to obtain a PVC composite material for high flame retardant coating of PU.

[0047] The solution of this application will be described below with reference to the following specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available products, and the devices or equipment used are all purchased from conventional market sales channels.

[0048] The specific embodiments are as follows: The preparation method of the modified activated carbon used in Examples 1 to 3 is as follows:

[0049] Step 1: Soak activated carbon in copper nitrate solution and let it stand at room temperature for 15 hours; the solid-liquid ratio of activated carbon to copper nitrate solution is 1:10, and the concentration of copper nitrate solution is 0.5 mol / L.

[0050] Step 2: Remove the soaked activated carbon and let it air dry naturally at room temperature for 6 hours. Then place it in an oven and dry it at 100℃ for 10 hours.

[0051] Step 3: Place the dried activated carbon into a muffle furnace and calcine it at 400°C at a rate of 5°C / min in an air atmosphere for 4 hours.

[0052] Step 4: Cool the calcined activated carbon naturally to room temperature in a muffle furnace, sieve it, and obtain modified activated carbon.

[0053] Examples 1-3

[0054] Example 1

[0055] This embodiment provides a high flame-retardant PVC composite material for PU coating. By weight, its raw material composition includes: 60 parts of polyvinyl chloride resin, 40 parts of chlorinated polyvinyl chloride resin, 80 parts of dioctyl terephthalate, 8 parts of stabilizer, 30 parts of magnesium hydroxide, 4 parts of zinc borate, 4 parts of antimony trioxide, 0.5 parts of lubricant, 10 parts of modified activated carbon, and 2 parts of nano lanthanum oxide.

[0056] Among them, the polyvinyl chloride resin is PVC-1300; the chlorine content of the chlorinated polyvinyl chloride resin is 70%; the stabilizer is bisphenol A phosphite; the lubricant is pentaerythritol stearate; the average particle size of the modified activated carbon is 75μm; and the average particle size of the nano-lanthanum oxide is 50nm.

[0057] The preparation method includes the following steps:

[0058] Step S1: Magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added. The mixture is stirred at 400 rpm for 10 min at 80°C to obtain a premix.

[0059] Step S2: Add dioctyl terephthalate, stabilizer and lubricant to the premix, mix at 800 rpm for 10 min at 100℃ to obtain the mixture.

[0060] Step S3: The mixture is fed into a twin-screw extruder for melt blending. The temperature of the feeding section is 145℃, the temperature of the compression section is 165℃, the temperature of the metering section is 180℃, the screw speed is 100rpm, and the mixture is extruded, cooled, drawn, and cut to obtain a high flame-retardant PVC composite material for PU coating.

[0061] Example 2

[0062] This embodiment provides a high flame-retardant PVC composite material for PU coating. By weight, its raw material composition includes: 50 parts of polyvinyl chloride resin, 50 parts of chlorinated polyvinyl chloride resin, 70 parts of dioctyl terephthalate, 5 parts of stabilizer, 40 parts of magnesium hydroxide, 6 parts of zinc borate, 6 parts of antimony trioxide, 0.8 parts of lubricant, 8 parts of modified activated carbon, and 1 part of nano lanthanum oxide.

[0063] Among them, the polyvinyl chloride resin is PVC-1300; the chlorine content of the chlorinated polyvinyl chloride resin is 70%; the stabilizer is bisphenol A phosphite; the lubricant is pentaerythritol stearate; the average particle size of the modified activated carbon is 75μm; and the average particle size of the nano-lanthanum oxide is 50nm.

[0064] The preparation method includes the following steps:

[0065] Step S1: Magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added. The mixture is stirred at 500 rpm for 8 minutes at a temperature of 70°C to obtain a premix.

[0066] Step S2: Add dioctyl terephthalate, stabilizer and lubricant to the premix, mix at 1000 rpm for 8 minutes at 90°C to obtain the mixture.

[0067] Step S3: The mixture is fed into a twin-screw extruder for melt blending. The temperature of the feeding section is 145℃, the temperature of the compression section is 165℃, the temperature of the metering section is 180℃, the screw speed is 200rpm, and the mixture is extruded, cooled, drawn, and cut to obtain a high flame-retardant PVC composite material for PU coating.

[0068] Example 3

[0069] This embodiment provides a high flame-retardant PVC composite material for PU coating. By weight, its raw material composition includes: 40 parts of polyvinyl chloride resin, 60 parts of chlorinated polyvinyl chloride resin, 60 parts of dioctyl terephthalate, 3 parts of stabilizer, 50 parts of magnesium hydroxide, 8 parts of zinc borate, 8 parts of antimony trioxide, 1 part of lubricant, 5 parts of modified activated carbon, and 0.5 parts of nano lanthanum oxide.

[0070] Among them, the polyvinyl chloride resin is PVC-1300; the chlorine content of the chlorinated polyvinyl chloride resin is 70%; the stabilizer is bisphenol A phosphite; the lubricant is pentaerythritol stearate; the average particle size of the modified activated carbon is 75μm; and the average particle size of the nano-lanthanum oxide is 50nm.

[0071] The preparation method includes the following steps:

[0072] Step S1: Magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added. The mixture is stirred at 600 rpm for 5 minutes at a temperature of 60°C to obtain a premix.

[0073] Step S2: Add dioctyl terephthalate, stabilizer and lubricant to the premix, mix at 1200 rpm for 5 minutes at 80°C to obtain the mixture.

[0074] Step S3: The mixture is fed into a twin-screw extruder for melt blending. The temperature of the feeding section is 145℃, the temperature of the compression section is 165℃, the temperature of the metering section is 180℃, the screw speed is 300rpm, and the mixture is extruded, cooled, drawn, and cut to obtain a high flame-retardant PVC composite material for PU coating.

[0075] Comparative Examples 1-2

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 2 is that no modified activated carbon was added in Comparative Example 1.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 did not include nano-lanthanum oxide.

[0080] Experimental testing

[0081] Test items and test methods: Flame retardancy: The oxygen index (LOI) of the composite material is tested according to ASTM D 2863. The higher the oxygen index, the better the flame retardancy of the material.

[0082] Corrosion resistance: The chemical resistance of the prepared composite material was tested according to GB / T 11547-2008: "Determination of the resistance of plastics to liquid chemical reagents". The reagents used were 40% nitric acid and 10% ammonium hydroxide. The soaking temperature was 70℃ and the soaking time was 96h. The appearance changes of the samples were observed.

[0083] The levels of appearance change are: no change, inconspicuous change, slight change, moderate change, and severe change.

[0084] Abrasion resistance: The abrasion resistance of the composite material was tested according to ASTM D4060-14. The abrasion cycle was 1000 times, conducted at room temperature and relative humidity of 50%. The presence of obvious scratches or peeling on the sample surface was observed and recorded.

[0085] Smoke suppression effect: A vertical combustion test was conducted according to UL 94. The sample was ignited and the smoke production during the combustion process was observed and recorded.

[0086] The flame retardant PU-coated PVC composite materials prepared in Examples 1-3 and Comparative Examples 1-2 were tested for flame retardancy, corrosion resistance, abrasion resistance and smoke suppression effect. The test results are shown in Table 1.

[0087] Table 1

[0088]

[0089] As can be seen from the test results in Table 1, the PVC composite materials prepared in Examples 1 to 3 have high oxygen index, small oxygen index reduction rate after salt spray test, and good performance in abrasion resistance test and smoke suppression test, indicating that the composite material has excellent flame retardancy, corrosion resistance, abrasion resistance and smoke suppression effect.

[0090] In Comparative Example 1, without the addition of modified activated carbon, the oxygen index of the prepared composite material decreased significantly. The oxygen index reduction rate increased after the salt spray test. Scratches appeared in the wear resistance test, and black toxic smoke was emitted, indicating that the flame retardancy, corrosion resistance, wear resistance, and smoke suppression effect of the composite material were all reduced.

[0091] In Comparative Example 2, without the addition of nano-lanthanum oxide, the resulting composite material showed varying degrees of decline in flame retardancy, corrosion resistance, wear resistance, and smoke suppression.

[0092] Examples 4-14

[0093] Example 4

[0094] The difference between Example 4 and Example 2 is that in Example 4, the stabilizer is methyl tin mercaptan.

[0095] Example 5

[0096] The difference between Example 5 and Example 2 is that in Example 5, the total weight of magnesium hydroxide, zinc borate and antimony trioxide is 52 parts, and the weight ratio of magnesium hydroxide, zinc borate and antimony trioxide is 8:1:1.

[0097] Example 6

[0098] The difference between Example 6 and Example 2 is that in Example 6, the lubricant is oxidized polyethylene wax.

[0099] Example 7

[0100] The difference between Example 7 and Example 2 is that in Example 7, the average particle size of the modified activated carbon is 110 μm.

[0101] Example 8

[0102] The difference between Example 8 and Example 2 is that in Example 8, the average particle size of the modified activated carbon is 150 μm.

[0103] Example 9

[0104] The difference between Example 9 and Example 2 is that in Example 9, the total weight of modified activated carbon and nano lanthanum oxide is 9 parts, and the weight ratio of modified activated carbon to nano lanthanum oxide is 6:1.

[0105] Example 10

[0106] The difference between Example 10 and Example 2 is that in Example 10, the total weight of modified activated carbon and nano lanthanum oxide is 9 parts, and the weight ratio of modified activated carbon to nano lanthanum oxide is 12:1.

[0107] Example 11

[0108] The difference between Example 11 and Example 7 is that in Example 11, the solid-liquid ratio of activated carbon and copper nitrate solution is 1:15 when preparing modified activated carbon.

[0109] Example 12

[0110] The difference between Example 12 and Example 7 is that in Example 12, the solid-liquid ratio of activated carbon and copper nitrate solution is 1:20 when preparing modified activated carbon.

[0111] Example 13

[0112] The difference between Example 13 and Example 11 is that in Example 13, during the preparation of modified activated carbon, in step three, the activated carbon is heated to 500°C at a rate of 8°C / min for calcination for 3 hours.

[0113] Example 14

[0114] The difference between Example 14 and Example 11 is that in Example 14, during the preparation of modified activated carbon, in step three, the activated carbon is heated to 600°C at a rate of 10°C / min for calcination, and the calcination time is 2 hours.

[0115] The flame retardant PU-coated PVC composite materials prepared in Examples 4-14 were tested for flame retardancy, corrosion resistance, abrasion resistance and smoke suppression effect. The test results are shown in Table 2.

[0116] Table 2

[0117]

[0118] As can be seen from the test results in Table 2, the difference between Example 4, Example 6 and Example 2 is that different stabilizers and lubricants were selected, and the resulting composite material has excellent flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0119] The difference between Example 5 and Example 2 is that the weight ratios of magnesium hydroxide, zinc borate, and antimony trioxide are different. The composite material prepared in Example 2 has better flame retardancy.

[0120] The difference between Examples 7 and 8 and Example 2 is that the average particle size of the modified activated carbon is different. Among them, the composite material prepared in Example 7 has the best flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0121] The difference between Examples 9 and 10 and Example 2 is that the weight ratio of modified activated carbon to nano-lanthanum oxide is different. Among them, the composite material prepared in Example 2 has better flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0122] The difference between Examples 11, 12 and 7 is that the solid-liquid ratio of activated carbon and copper nitrate solution is different when preparing modified activated carbon. Among them, the composite material prepared in Example 11 has the best flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0123] The difference between Examples 13 and 14 and Example 11 is that the calcination parameters are different when preparing the modified activated carbon. Among them, the composite material obtained in Example 13 has the best flame retardancy, corrosion resistance, wear resistance and smoke suppression effect.

[0124] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the principles of this application should be included within the protection scope of this application.

Claims

1. A PVC composite material for high flame retardant PU coating, characterized in that, By weight, its raw material composition includes: 40-60 parts of polyvinyl chloride resin, 40-60 parts of chlorinated polyvinyl chloride resin, 60-80 parts of dioctyl terephthalate, 3-8 parts of stabilizer, 30-50 parts of magnesium hydroxide, 4-8 parts of zinc borate, 4-8 parts of antimony trioxide, 0.5-1 part of lubricant, 5-10 parts of modified activated carbon, and 0.5-2 parts of nano-lanthanum oxide; The method for preparing the modified activated carbon is as follows: Step 1: Soak activated carbon in copper nitrate solution and let it stand at room temperature for 6 to 24 hours; the solid-liquid ratio of activated carbon to copper nitrate solution is 1:(10 to 20), and the concentration of copper nitrate solution is 0.5 mol / L; Step 2: Remove the soaked activated carbon and dry it. Step 3: Place the dried activated carbon into a muffle furnace and calcine it at a rate of 5℃ / min~10℃ / min to 400℃~600℃ in an air atmosphere for 2h~4h. Step 4: Cool the calcined activated carbon naturally to room temperature in a muffle furnace, sieve it, and obtain the modified activated carbon.

2. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, By weight, its raw material composition includes: 50 parts polyvinyl chloride resin, 50 parts chlorinated polyvinyl chloride resin, 70 parts dioctyl terephthalate, 5 parts stabilizer, 40 parts magnesium hydroxide, 6 parts zinc borate, 6 parts antimony trioxide, 0.8 parts lubricant, 8 parts modified activated carbon, and 1 part nano lanthanum oxide.

3. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, The stabilizer includes at least one of bisphenol A phosphite, dibutyltin dilaurate, and methyltin mercaptan.

4. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, The weight ratio of the magnesium hydroxide, the zinc borate, and the antimony trioxide is 6~8:1~2:1~2.

5. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, The lubricant includes at least one of pentaerythritol stearate, oxidized polyethylene wax, and silicone oil.

6. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, The modified activated carbon has an average particle size of 75 μm to 150 μm.

7. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, The weight ratio of the modified activated carbon to the nano-lanthanum oxide is 6~12:

1.

8. The PVC composite material for high flame retardant PU coating according to claim 1, characterized in that, In step two of the modified activated carbon preparation method, the drying process includes: air-drying the activated carbon naturally at room temperature for 4 to 8 hours, and then placing it in an oven and drying it at 80°C to 120°C for 8 to 12 hours.

9. A method for preparing a high flame-retardant PVC composite material for PU coating according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step S1: The magnesium hydroxide, zinc borate and antimony trioxide are initially mixed, and then the polyvinyl chloride resin, chlorinated polyvinyl chloride resin, modified activated carbon and nano lanthanum oxide are added. The mixture is stirred at 400 rpm to 600 rpm for 5 min to 10 min at a temperature of 60 ℃ to 80 ℃ to obtain a premix. Step S2: Add the dioctyl terephthalate, the stabilizer, and the lubricant to the premix, and mix at a stirring speed of 800 rpm to 1200 rpm for 5 min to 10 min at a temperature of 80℃ to 100℃ to obtain the mixture. Step S3: The mixture is fed into a twin-screw extruder for melt blending at a temperature of 140℃~180℃ and a screw speed of 100rpm~300rpm. The mixture is then extruded, cooled, drawn, and cut to obtain a PVC composite material for high flame retardant coating of PU.

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