Aging-resistant PVC composite material and preparation method thereof

Abstract

The application provides an anti-aging PVC composite material and a preparation method thereof, and belongs to the technical field of PVC composite materials.The preparation method comprises the steps of preparing a ternary powder, preparing carbon dots and composite molding.The ternary powder preparation step is as follows: the mixed salt solution is raised to a temperature of 58-62 DEG C, the theanine solution is added at a uniform speed, the adding time is controlled to be 10-12 min, the stirring speed is controlled to be 120-140 rpm at the same time of adding, after the adding is completed, the stirring is continuously performed for 5-6 min, then the sodium hydroxide solution is added, the pH value of the system is controlled to be 9.5-10.5, the system is kept at 88-93 DEG C for 110-120 min, the temperature is naturally reduced to 72-75 DEG C, the stirring is kept for 38-43 min, and then the ternary powder is obtained after centrifugation, washing and drying.The PVC composite material prepared by the application has strong mechanical properties and excellent anti-aging performance.

Description

Technical Field

[0001] This invention belongs to the field of PVC composite material technology, specifically relating to an aging-resistant PVC composite material and its preparation method. Background Technology

[0002] PVC, or polyvinyl chloride, is one of the most widely produced and used general-purpose polymer materials. It possesses excellent mechanical properties, corrosion resistance, insulation properties, and molding and processing properties, and is widely used in cable sheathing, building profiles, piping systems, packaging materials, and other fields. It is an indispensable basic polymer material in national economic construction and has extremely high industrial and market application value. With the increasing demand for applications in harsh conditions such as outdoor scenes, high temperature and humidity, and strong ultraviolet radiation, the aging resistance and weather resistance of PVC composite materials have become core objectives for measuring material quality.

[0003] However, PVC material itself has significant structural defects. Its molecular chain contains unstable tertiary carbon atoms and allyl chloride atoms, which are highly reactive groups. Under the influence of long-term ultraviolet radiation, damp heat aging, oxygen oxidation and other external environmental factors, it is very easy to undergo dehydrochlorination degradation reaction, which triggers molecular chain breakage, cross-linking and degradation reactions. Ultimately, this leads to PVC composite materials yellowing, powdering, cracking, sharp decline in mechanical properties, and dimensional deformation. It cannot meet the requirements of long-term outdoor service and high-durability working conditions, and seriously shortens the service life of PVC composite materials.

[0004] Therefore, improving the aging resistance of PVC composite materials is a core research direction in the PVC field.

[0005] Currently, the main technical solutions for improving PVC composite materials include the following: The first method is to add anti-aging additives, including ultraviolet absorbers, hindered amine light stabilizers, antioxidants, etc., which delay material aging by capturing free radicals, absorbing ultraviolet light, and inhibiting oxidation reactions. The second method is to add inorganic nanoparticles, such as nano titanium dioxide, nano zinc oxide, talc, and kaolin, which utilize the ultraviolet shielding and heat insulation properties of inorganic powders to improve the weather resistance of materials. The third method involves optimizing the formulation of plasticizers and heat stabilizers to reduce the thermal and oxidative aging degradation of PVC during processing and use.

[0006] However, the existing solutions have the following shortcomings: First, single anti-aging agents have small molecular weights and limited compatibility with PVC resin. During long-term use, they are prone to migration, precipitation, and volatilization, leading to a rapid decline in the material's anti-aging properties and causing phenomena such as frosting and stickiness on the surface of the product, failing to achieve long-term protection. Second, conventional inorganic nanofillers are prone to agglomeration and poor dispersibility. They cannot be uniformly dispersed in the PVC matrix, easily forming stress concentration points. This not only fails to provide stable anti-aging effects but also reduces the tensile strength, toughness, and other mechanical properties of PVC composites, shortening their service life. Third, existing compounding schemes are mostly simple physical mixtures. The interfacial bonding between plasticizers, heat stabilizers, and other additives, fillers, and the PVC matrix is ​​weak, resulting in poor synergistic anti-aging effects. Furthermore, the compounding system affects the processing flowability and molding precision of PVC composites, and some schemes require the addition of high amounts of additives and fillers, significantly increasing production costs.

[0007] Therefore, providing an aging-resistant PVC composite material and its preparation method, avoiding the loss of additives, improving the mechanical properties of the product, enhancing the interfacial compatibility between raw materials, and enhancing the aging resistance of the composite material are technical problems that urgently need to be solved in the existing technology. Summary of the Invention

[0008] To address the technical problems existing in the prior art, this invention provides an aging-resistant PVC composite material and its preparation method, which avoids the loss and migration of additives, enhances the compatibility between raw materials, and results in a PVC composite with good mechanical properties and excellent aging resistance.

[0009] To address the aforementioned technical problems, this invention provides a method for preparing aging-resistant PVC composite materials, comprising the steps of preparing ternary powder, preparing carbon dots, and composite molding, as detailed below: 1. Preparation of ternary powder Magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate were added to deionized water and stirred until completely dissolved to obtain a mixed salt solution; theanine was added to deionized water and dissolved to obtain a theanine solution. In the mixed salt solution, the mass ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, lanthanum nitrate hexahydrate, and deionized water is 10.5-10.8:3.8-4.2:0.5-0.6:65. In the theanine solution, the mass ratio of theanine to deionized water is 0.2-0.3:20; The temperature of the mixed salt solution is raised to 58-62℃, and theanine solution is added at a uniform rate over a period of 10-12 minutes. The stirring speed is maintained at 120-140 rpm during the addition. After the addition is complete, stirring is continued for 5-6 minutes. Then, 6-10 wt% sodium hydroxide solution is added, and the pH of the system is controlled at 9.5-10.5. The temperature is then raised to 88-93℃ at a rate of 0.8-1.2℃ / min and held for 110-120 minutes. After the holding period, the temperature is naturally lowered to 72-75℃, and the mixture is stirred at 180-210 rpm for 38-43 minutes to mature. After centrifugation, the mixture is washed and dried to obtain ternary powder. The mass ratio of the mixed salt solution to the theanine solution is 78-82:18-23.

[0010] 2. Preparation of carbon dots Citric acid, ethylenediamine, and PVP K30 were added to deionized water and stirred for 4-6 minutes. The mixture was then ultrasonically dispersed for 8-12 minutes at a power of 100-120 W and a frequency of 34-37 kHz. The mixture was then transferred to a hydrothermal reactor and hydrothermally reacted at 178-183℃ for 5.8-6.0 hours. After the reaction was completed, the mixture was allowed to return to room temperature naturally. After filtration and drying, carbon dots were obtained. The mass ratio of citric acid, ethylenediamine, and PVP K30 is 1.8-2.2g:1.4-1.6mL:0.14-0.17g.

[0011] 3. Composite molding (1) Primary compound Carbon dots were added to deionized water and dissolved evenly to obtain a carbon dot solution of 0.8-1.2 g / L. Ternary powder was added to deionized water and ultrasonically dispersed for 30-35 min at an ultrasonic power of 110-120 W and an ultrasonic frequency of 28-35 kHz to obtain a ternary powder suspension of 0.8-1.2 g / L. The carbon dot solution was added to the ternary powder suspension, and the mass ratio of carbon dots to ternary powder was controlled at 1:6-8. The mixture was stirred at 55-60℃ for 7-8 h, centrifuged, and dried to obtain the primary composite agent. (2) Molding PVC resin SG-8, halloysite nanotubes, primary composite agent, epoxidized soybean oil, calcium stearate, polyethylene wax, calcium-zinc stabilizer, ACR-401 processing aid, and dioctyl phthalate are added to a high-speed mixer and stirred at 600-700 rpm for 40-50 minutes at a stirring temperature of 95-100℃. After stirring, the mixture is cooled to room temperature to obtain a mixture. The mixture is then added to a twin-screw extruder, and the extrusion temperature is set to 165-175℃ and the screw speed to 200-220 rpm. After mixing, the mixture is molded at 180-185℃ and 9-10 MPa for 5-7 minutes. After cooling and setting, an aging-resistant PVC composite material is obtained. The mass ratio of the PVC resin SG-8, halloysite nanotubes, primary composite agent, epoxidized soybean oil, calcium stearate, polyethylene wax, calcium-zinc stabilizer, ACR-401 processing aid, and dioctyl phthalate is 100:8-10:5-6:3-5:0.5-1.0:0.5-1.0:3-4:1.2-1.8:8-10.

[0012] An aging-resistant PVC composite material is prepared using the aforementioned preparation method.

[0013] This invention employs a specific method to prepare PVC composite materials. First, magnesium-aluminum-lanthanum layered bimetallic hydroxide is prepared via co-precipitation-crystallization. Then, theanine is used for intercalation treatment. The organic segments of theanine improve the compatibility with ternary powders and PVC resin, and lanthanum enhances the thermal stability of the composite material. The interlayer spacing of the theanine-treated ternary powder increases, which is beneficial for the entry of PVC molecular chains, improves the dispersibility of fillers, and enhances stability. During the carbon dot preparation process, PVP K30 is added as a surfactant to enhance the dispersibility of carbon dots, prevent agglomeration, and improve affinity with ternary powders. In the composite molding step, carbon dots can be loaded onto the surface of theanine-intercalated ternary powders, achieving liquid-phase self-assembly to form a composite aging-resistant system that is not easily migrated or lost. Halloysite nanotubes, as natural nanotube-shaped reinforcing fillers, can improve the strength, modulus, and toughness of the composite material. Combined with other additives, the migration and diffusion of small additive molecules to the surface can be prevented, effectively improving the mechanical properties of the composite material while enhancing its aging resistance and extending its service life.

[0014] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The PVC composite material obtained by this invention has a tensile strength of 44.8-48.7 MPa and a notched impact strength of 22.6-25.3 MPa. 2. The PVC composite material obtained by this invention has a flexural strength of 74.9-80.1 MPa and a flexural modulus of 3316-3347 MPa; 3. The PVC composite material obtained by this invention, when placed in an air environment and subjected to heat aging at 100°C for 168 hours, exhibits a tensile strength of 42.6-47.0 MPa, a notched impact strength of 21.4-24.2 MPa, and a flexural strength of 71.5-77.8 MPa. Detailed Implementation

[0015] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0016] Example 1 1. Preparation of ternary powder 10.5g magnesium nitrate hexahydrate, 3.8g aluminum nitrate nonahydrate, and 0.5g lanthanum nitrate hexahydrate were added to 65g of deionized water and stirred until completely dissolved to obtain a mixed salt solution; 0.2g theanine was added to 20g of deionized water and dissolved to obtain a theanine solution. The temperature of 78g of mixed salt solution was raised to 58℃, and 18g of theanine solution was added at a constant rate over a period of 10min. The stirring speed was maintained at 120rpm during the addition. After the addition was completed, stirring was continued for 5min. Then, 6wt% sodium hydroxide solution was added, and the pH of the system was controlled at 9.5. The temperature was then raised to 88℃ at a rate of 0.8℃ / min and held for 110min. After the holding period, the temperature was naturally lowered to 72℃, and the mixture was stirred at 180rpm for 38min to mature. After centrifugation, the mixture was washed and dried to obtain ternary powder.

[0017] 2. Preparation of carbon dots 1.8 g citric acid, 1.4 mL ethylenediamine, and 0.14 g PVP K30 were added to deionized water, stirred for 4 min, and ultrasonically dispersed for 8 min at a power of 100 W and a frequency of 34 kHz. The mixture was then transferred to a hydrothermal reactor and hydrothermally reacted at 178 °C for 5.8 h. After the reaction was completed, the mixture was allowed to return to room temperature naturally. After filtration and drying, carbon dots were obtained.

[0018] 3. Composite molding (1) Primary compound Carbon dots were added to deionized water and dissolved evenly to obtain a 0.8 g / L carbon dot solution. Ternary powder was added to deionized water and ultrasonically dispersed for 30 min at an ultrasonic power of 110 W and an ultrasonic frequency of 28 kHz to obtain a 0.8 g / L ternary powder suspension. The carbon dot solution was added to the ternary powder suspension, and the mass ratio of carbon dots to ternary powder was controlled at 1:6. The mixture was stirred at 55 °C for 7 h, centrifuged, and dried to obtain the primary composite agent. (2) Molding 100g of PVC resin SG-8, 8g of halloysite nanotubes, 5g of primary composite agent, 3g of epoxidized soybean oil, 0.5g of calcium stearate, 0.5g of polyethylene wax, 3g of calcium-zinc stabilizer, 1.2g of ACR-401 processing aid, and 8g of dioctyl phthalate were added to a high-speed mixer and stirred at 600 rpm for 40 minutes at a stirring temperature of 95℃. After stirring, the mixture was cooled to room temperature to obtain a mixture. The mixture was then added to a twin-screw extruder, and the extrusion temperature was set to 165℃ and the screw speed to 200 rpm. After mixing, the mixture was molded at 180℃ and 9MPa for 5 minutes. After cooling and setting, an aging-resistant PVC composite material was obtained.

[0019] Example 2 1. Preparation of ternary powder 10.6g magnesium nitrate hexahydrate, 4.0g aluminum nitrate nonahydrate and 0.5g lanthanum nitrate hexahydrate were added to 65g deionized water and stirred until completely dissolved to obtain a mixed salt solution; 0.2g theanine was added to 20g deionized water and dissolved to obtain a theanine solution. The temperature of 80g of mixed salt solution was raised to 60℃, and 20g of theanine solution was added at a constant rate over a period of 12min. The stirring speed was maintained at 130rpm during the addition. After the addition was completed, stirring was continued for 6min. Then, 8wt% sodium hydroxide solution was added, and the pH of the system was controlled at 10.0. The temperature was then raised to 90℃ at a rate of 1.0℃ / min and held for 115min. After the holding period, the temperature was naturally lowered to 73℃, and the mixture was stirred at 200rpm for 40min to mature. After centrifugation, the mixture was washed and dried to obtain ternary powder.

[0020] 2. Preparation of carbon dots Add 2.0g citric acid, 1.5mL ethylenediamine, and 0.15g PVP K30 to deionized water, stir for 5min, and ultrasonically disperse for 10min. The ultrasonic power is 110W and the ultrasonic frequency is 35kHz. Then transfer it to a hydrothermal reactor and hydrothermally react at 180℃ for 6.0h. After the reaction is completed, allow it to return to room temperature naturally, filter, and dry to obtain carbon dots.

[0021] 3. Composite molding (1) Primary compound Carbon dots were added to deionized water and dissolved evenly to obtain a 1.0 g / L carbon dot solution. Ternary powder was added to deionized water and ultrasonically dispersed for 32 min at an ultrasonic power of 115 W and an ultrasonic frequency of 30 kHz to obtain a 1.0 g / L ternary powder suspension. The carbon dot solution was added to the ternary powder suspension, and the mass ratio of carbon dots to ternary powder was controlled at 1:7. The mixture was stirred at 58 °C for 8 h, centrifuged, and dried to obtain the primary composite agent. (2) Molding 100g of PVC resin SG-8, 9g of halloysite nanotubes, 6g of primary composite agent, 4g of epoxidized soybean oil, 0.8g of calcium stearate, 0.7g of polyethylene wax, 4g of calcium-zinc stabilizer, 1.5g of ACR-401 processing aid, and 9g of dioctyl phthalate were added to a high-speed mixer and stirred at 650 rpm for 45 minutes at a stirring temperature of 98℃. After stirring, the mixture was cooled to room temperature to obtain a mixture. The mixture was then added to a twin-screw extruder, and the extrusion temperature was set to 170℃ and the screw speed to 210 rpm. After mixing, the mixture was molded at 182℃ and 10MPa for 6 minutes. After cooling and setting, an aging-resistant PVC composite material was obtained.

[0022] Example 3 1. Preparation of ternary powder 10.8g magnesium nitrate hexahydrate, 4.2g aluminum nitrate nonahydrate, and 0.6g lanthanum nitrate hexahydrate were added to 65g of deionized water and stirred until completely dissolved to obtain a mixed salt solution; 0.3g theanine was added to 20g of deionized water and dissolved to obtain a theanine solution. The temperature of 82g of mixed salt solution was raised to 62℃, and 23g of theanine solution was added at a constant rate over a period of 12min. The stirring speed was maintained at 140rpm during the addition. After the addition was completed, stirring was continued for 6min. Then, 10wt% sodium hydroxide solution was added, and the pH of the system was controlled at 10.5. The temperature was then raised to 93℃ at a rate of 1.2℃ / min and held for 120min. After the holding period, the temperature was naturally lowered to 75℃, and the mixture was stirred at 210rpm for 43min to mature. After centrifugation, the mixture was washed and dried to obtain ternary powder.

[0023] 2. Preparation of carbon dots 2.2g citric acid, 1.6mL ethylenediamine, and 0.17g PVP K30 were added to deionized water and stirred for 6min. The mixture was then ultrasonically dispersed for 12min at a power of 120W and a frequency of 37kHz. The mixture was then transferred to a hydrothermal reactor and hydrothermally reacted at 183℃ for 6.0h. After the reaction was completed, the mixture was allowed to return to room temperature naturally. After filtration and drying, carbon dots were obtained.

[0024] 3. Composite molding (1) Primary compound Carbon dots were added to deionized water and dissolved evenly to obtain a 1.2 g / L carbon dot solution. Ternary powder was added to deionized water and ultrasonically dispersed for 35 min at an ultrasonic power of 120 W and an ultrasonic frequency of 35 kHz to obtain a 1.2 g / L ternary powder suspension. The carbon dot solution was added to the ternary powder suspension, and the mass ratio of carbon dots to ternary powder was controlled at 1:8. The mixture was stirred at 60 °C for 8 h, centrifuged, and dried to obtain the primary composite agent. (2) Molding 100g of PVC resin SG-8, 10g of halloysite nanotubes, 6g of primary composite agent, 5g of epoxidized soybean oil, 1.0g of calcium stearate, 1.0g of polyethylene wax, 4g of calcium-zinc stabilizer, 1.8g of ACR-401 processing aid, and 10g of dioctyl phthalate were added to a high-speed mixer and stirred at 700 rpm for 50 minutes at a stirring temperature of 100℃. After stirring, the mixture was cooled to room temperature to obtain a mixture. The mixture was then added to a twin-screw extruder, and the extrusion temperature was set to 175℃ and the screw speed to 220 rpm. After mixing, the mixture was molded at 185℃ and 10MPa for 7 minutes. After cooling and setting, an aging-resistant PVC composite material was obtained.

[0025] Comparative Example 2.1 Based on Example 2, the following changes were made: 1. Preparation of ternary powder 10.6g magnesium nitrate hexahydrate, 4.0g aluminum nitrate nonahydrate and 0.5g lanthanum nitrate hexahydrate were stirred at 150rpm for 20min to obtain ternary powder; 2. Preparation of carbon dots The operation is exactly the same as in Example 2; 3. Composite molding The operation is exactly the same as in Example 2.

[0026] Comparative Example 2.2 Based on Example 2, the following changes were made: 1. Preparation of ternary powder The steps “add 20g of theanine solution at a uniform speed, control the addition time to 12min, control the stirring speed to 130rpm while adding, and continue stirring for 6min after the addition is completed” are omitted. 2. Preparation of carbon dots "0.15g PVP K30" is omitted; 3. Composite molding The primary composite step is omitted. In the molding step, the primary composite agent is replaced in equal amounts with a mixture of ternary powder and carbon dots, with a mass ratio of carbon dots to ternary powder of 1:7. The rest of the operations are exactly the same.

[0027] Performance testing The PVC composite materials obtained in Examples 1-3, Comparative Example 2.1, and Comparative Example 2.2 were subjected to performance tests, and the results are as follows:

[0028] The PVC composite materials obtained in Examples 1-3, Comparative Example 2.1, and Comparative Example 2.2 were placed in an air environment and subjected to heat aging at 100°C for 168 hours. Performance tests were then conducted again, and the results are as follows:

[0029] Comparative Example 2.1 directly used a mixture of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and lanthanum nitrate hexahydrate as the ternary powder. This could not produce layered bimetallic hydroxides, and its compatibility with halloysite nanotubes and the PVC matrix was poor, thus losing its reinforcing effect. Furthermore, it caused severe agglomeration within the PVC matrix, creating stress concentration points, which led to a decrease in mechanical properties, a rapid decline in strength after thermal aging, and a significantly shortened lifespan. Comparative Example 2.2 did not treat the ternary powder with theanine, did not add PVP during the preparation of carbon dots, and directly mixed the ternary powder and carbon dots with other components during the composite molding process. This prevented uniform mixing with the PVC matrix, resulting in a decrease in the overall performance of the final product.

[0030] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0031] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an aging-resistant PVC composite material, characterized in that, This includes steps such as preparing ternary powder, preparing carbon dots, and composite molding. The steps for preparing ternary powder are as follows: The temperature of the mixed salt solution is raised to 58-62℃, and theanine solution is added at a uniform rate over a period of 10-12 minutes. Simultaneously, the stirring speed is controlled at 120-140 rpm. After addition, stirring is continued for 5-6 minutes. Then, sodium hydroxide solution is added, and the pH of the system is controlled at 9.5-10.

5. The temperature is maintained at 88-93℃ for 110-120 minutes, and then naturally lowered to 72-75℃. The mixture is stirred and matured for 38-43 minutes. After centrifugation, the mixture is washed and dried to obtain the ternary powder. The mixed salt solution is a mixture of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, lanthanum nitrate hexahydrate, and deionized water. The theanine solution is a mixture of theanine and deionized water.

2. The method for preparing an aging-resistant PVC composite material according to claim 1, characterized in that, In the step of preparing ternary powder, the mass ratio of the mixed salt solution to the theanine solution is 78-82:18-23; In the mixed salt solution, the mass ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, lanthanum nitrate hexahydrate, and deionized water is 10.5-10.8:3.8-4.2:0.5-0.6:

65. In the theanine solution, the mass ratio of theanine to deionized water is 0.2-0.3:

20.

3. The method for preparing an aging-resistant PVC composite material according to claim 1, characterized in that, The preparation steps for carbon dots are as follows: citric acid, ethylenediamine, and PVP K30 are added to deionized water, stirred for 4-6 minutes, ultrasonically dispersed for 8-12 minutes with an ultrasonic power of 100-120W and an ultrasonic frequency of 34-37kHz, and then transferred to a hydrothermal reactor. The mixture is then subjected to a hydrothermal reaction at 178-183℃ for 5.8-6.0 hours. After the reaction is completed, the mixture is allowed to return to room temperature naturally, filtered, and dried to obtain carbon dots.

4. The method for preparing an aging-resistant PVC composite material according to claim 3, characterized in that, The mass ratio of citric acid, ethylenediamine, and PVP K30 is 1.8-2.2g:1.4-1.6mL:0.14-0.17g.

5. The method for preparing an aging-resistant PVC composite material according to claim 1, characterized in that, The composite molding step includes a primary composite step and a molding step; The primary composite step is as follows: carbon dots are added to deionized water and dissolved evenly to obtain a carbon dot solution of 0.8-1.2 g / L; ternary powder is added to deionized water and ultrasonically dispersed for 30-35 min at an ultrasonic power of 110-120 W and an ultrasonic frequency of 28-35 kHz to obtain a ternary powder suspension of 0.8-1.2 g / L; the carbon dot solution is added to the ternary powder suspension, and the mass ratio of carbon dots to ternary powder is controlled at 1:6-8. The mixture is stirred at 55-60℃ for 7-8 h, and then dried after centrifugation to obtain the primary composite agent.

6. The method for preparing an aging-resistant PVC composite material according to claim 5, characterized in that, The molding step involves adding PVC resin SG-8, halloysite nanotubes, primary composite agent, epoxidized soybean oil, calcium stearate, polyethylene wax, calcium-zinc stabilizer, ACR-401 processing aid, and dioctyl phthalate into a high-speed mixer and stirring at 600-700 rpm for 40-50 minutes at a stirring temperature of 95-100℃. After stirring, the mixture is cooled to room temperature to obtain a mixture. The mixture is then added to a twin-screw extruder, with the extrusion temperature set at 165-175℃ and the screw speed at 200-220 rpm. After mixing, the mixture is molded at 180-185℃ and 9-10 MPa for 5-7 minutes. After cooling and setting, an aging-resistant PVC composite material is obtained.

7. The method for preparing an aging-resistant PVC composite material according to claim 6, characterized in that, The mass ratio of the PVC resin SG-8, halloysite nanotubes, primary composite agent, epoxidized soybean oil, calcium stearate, polyethylene wax, calcium-zinc stabilizer, ACR-401 processing aid, and dioctyl phthalate is 100:8-10:5-6:3-5:0.5-1.0:0.5-1.0:3-4:1.2-1.8:8-10.

8. An aging-resistant PVC composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

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