Method for compounding dynamic plasticizing regulation type PVC (polyvinyl chloride) environment-friendly stabilizer

Abstract

The invention discloses a compounding method of a dynamic plasticizing regulation type PVC (polyvinyl chloride) environment-friendly stabilizer, and relates to the technical field of PVC processing aids. The invention discloses a dynamic plasticizing regulation type PVC (polyvinyl chloride) environment-friendly stabilizer. The graphene quantum dot / hydrotalcite composite material is prepared from the following raw materials in parts by weight: 20 to 30 parts of modified calcium stearate, 50 to 70 parts of modified tributyl citrate, 60 to 90 parts of hydrotalcite, 12 to 22 parts of organic tin, 18 to 28 parts of pentaerythritol, 16 to 22 parts of compound antioxidant, 4 to 10 parts of nano silicon dioxide, 22 to 32 parts of bio-based fatty acid, 2 to 6 parts of graphene quantum dots and 12 to 16 parts of methyl methacrylate-butadiene-styrene copolymer. 3-6 parts of an antistatic agent, 10-14 parts of a phosphorus-containing flame retardant, 4-10 parts of stearic acid and 3-7 parts of nano montmorillonite. According to the invention, calcium stearate and tributyl citrate are modified, so that the stabilizer is endowed with dynamic plasticizing regulation and control capability, and has multiple functions of efficient thermal stability, flame retardance and the like. The raw materials are environmentally friendly, low-temperature rapid plasticizing can be achieved, energy consumption is reduced, and the product is excellent in mechanical property, high in weather resistance and suitable for multiple scenes such as pipes and electronic packaging and conforms to the green and intelligent development trend.

Description

Technical Field

[0001] The invention relates to the technical field of PVC processing aids, in particular to a compounding method of a dynamic plasticizing controllable PVC environmentally friendly stabilizer. Background Art

[0002] Traditional PVC stabilizers often use compounds containing heavy metals. While these compounds offer excellent thermal stability, they pose health and environmental risks. As environmental standards rise, these stabilizers are gradually being phased out. Alternatives, such as calcium / zinc composite stabilizers, suffer from low thermal stabilization efficiency, reliance on petroleum-based raw materials, and poor compatibility with PVC recycling systems, hindering the development of green recycling.

[0003] Balancing plasticization uniformity and thermal stability is a key challenge in PVC processing. Traditional stabilizers are inadequately responsive to temperature and shear rate, easily leading to under- or over-plasticization and compromising product quality. Furthermore, existing methods struggle to achieve nanoscale dispersion, leading to inorganic powder agglomeration and organic component migration, further impairing the long-term performance of the product.

[0004] Modern PVC product demands are increasingly diverse. For example, electronic packaging requires the synergy of antistatic and flame retardant properties, agricultural films require weather resistance and sustained-release properties, and the medical field demands antimicrobial and halogen-free properties. Traditional stabilizers rely on multi-component formulations, often leading to phase separation and other issues due to poor compatibility, and some functional systems have environmental drawbacks.

[0005] Existing stabilizer modification technologies often focus on optimizing a single performance factor. For example, improving thermal stability can sacrifice long-term performance, while enhancing toughness can lead to reduced heat resistance. Environmentally friendly modifications also face challenges with raw material compatibility. Furthermore, process limitations, such as insufficient shear strength in mixing equipment and poor temperature control precision, lead to fluctuations in stabilizer performance, making it difficult to meet the uniformity requirements of industrial production.

[0006] These issues not only limit the application of PVC materials in high-end applications but also run counter to the green and intelligent industry trends. Breaking through the bottlenecks of traditional technologies and developing new stabilizers that combine high efficiency, stability, dynamic control, multifunctional integration, and environmental sustainability has become a key issue in the PVC processing industry. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the present invention provides a method for compounding a dynamic plasticizing and regulating PVC environmentally friendly stabilizer, which solves the above problems.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] A dynamic plasticizing and controllable PVC environmentally friendly stabilizer comprises the following raw materials in parts by weight: 20-30 parts of modified calcium stearate, 50-70 parts of modified tributyl citrate, 60-90 parts of hydrotalcite, 12-22 parts of organotin, 18-28 parts of pentaerythritol, 16-22 parts of compound antioxidant, 4-10 parts of nano-silicon dioxide, 22-32 parts of bio-based fatty acids, 2-6 parts of graphene quantum dots, 12-16 parts of methyl methacrylate-butadiene-styrene copolymer, 3-6 parts of antistatic agent, 10-14 parts of phosphorus-containing flame retardant, 4-10 parts of stearic acid, and 3-7 parts of nano-montmorillonite.

[0010] Furthermore, the bio-based fatty acid is one of castor oil fatty acid and palm kernel oil fatty acid; the antistatic agent is one of dodecyltrimethylammonium chloride and octadecyltrimethylammonium bromide; the phosphorus-containing flame retardant is one of triphenyl phosphate and resorcinol tetraphenyl diphosphate; and the compound antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0011] Furthermore, the modified calcium stearate is specifically prepared in the following steps:

[0012] A1. Calcium stearate was added to an ethanol-water mixed solution, and γ-aminopropyltriethoxysilane coupling agent was added at the same time. The mixture was ultrasonically dispersed for 40 minutes, and then the dispersion was transferred to an autoclave and stirred for 3 hours. After the reaction, the mixture was cooled to room temperature and centrifuged for 10 minutes. The precipitate was washed with ethanol and vacuum-dried at 60°C for 12 hours to obtain surface-modified nano-calcium stearate.

[0013] A2. Add the surface-modified nano-calcium stearate to the zinc nitrate solution, stir evenly, slowly add sodium hydroxide solution dropwise, adjust the pH to 10, and stir at 50°C for 4 hours; after the reaction, filter, wash the precipitate with deionized water until neutral, and vacuum dry at 80°C for 2 hours, and then calcine at 400°C for 3 hours to obtain zinc oxide-loaded calcium stearate;

[0014] A3. Add zinc oxide-loaded calcium stearate to a xylene solution, add maleic anhydride and dibenzoyl peroxide, and stir the mixture at 110°C under nitrogen protection for 5 hours. After the reaction, wash the product with acetone and vacuum dry it for 8 hours to obtain a functionalized composite-modified calcium stearate.

[0015] Furthermore, in step A1, the amount ratio of calcium stearate, ethanol-water mixed solution, and γ-aminopropyltriethoxysilane coupling agent is 25g:300mL:5mL; in the ethanol-water mixed solution, the volume ratio of ethanol to water is 7:3; the reaction conditions of the reactor are 120°C, 1.5MPa, and a stirring speed of 400r / min; the centrifugal speed is 8000r / min; and the precipitate is washed three times with ethanol.

[0016] Furthermore, in step A2, the surface-modified nano-calcium stearate and zinc nitrate solution are used in a ratio of 25 g:150 mL; the concentration of the zinc nitrate solution is 0.5 mol / L; the mass fraction of the sodium hydroxide solution is 20%; and the stirring speed is 400 r / min. In step A3, the xylene solution, maleic anhydride, and dibenzoyl peroxide are used in a ratio of 200 mL:8 g:0.5 g; the stirring speed is 300 r / min; and the vacuum drying conditions are 60°C and -0.09 MPa.

[0017] Through ultrasonic dispersion and treatment with γ-aminopropyltriethoxysilane coupling agent, calcium stearate particles are dispersed to the nanoscale, and the silane coupling agent forms Si-O-Ca bonds through hydrolysis and is coated on the surface of calcium stearate.

[0018] The amino groups of the coupling agent face outwards, which endows the particles with organophilicity and solves the compatibility problem between inorganic powder and PVC matrix.

[0019] Zinc nitrate reacts with sodium hydroxide to form a zinc hydroxide precipitate, which is chemically bonded to the surface of calcium stearate and converted to zinc oxide through calcination. ZnO, acting as a metal oxide stabilizer, inhibits PVC degradation by neutralizing HCl and capturing free radicals such as Cl·, while also forming a Ca-Zn synergistic stabilization system with calcium stearate.

[0020] Maleic anhydride is grafted onto the hydroxyl groups on the surface of calcium stearate using the free radical initiator dibenzoyl peroxide, introducing carboxylic acid groups and double bonds. The carboxylic acid groups form hydrogen bonds with the polar -Cl groups in the PVC molecular chain, enhancing interfacial bonding. The double bonds can cross-link with antioxidants, plasticizers, and other agents, improving overall compatibility.

[0021] Furthermore, the modified tributyl citrate is prepared in the following steps:

[0022] B1. Tributyl citrate was added to a reactor, followed by phosphotungstic acid, and hydrogen peroxide solution was slowly added dropwise at 45°C. After the addition was complete, the temperature was raised to 65°C and stirred for reaction for 5 hours. After the reaction was complete, the product was washed with saturated brine, the organic phase was separated, and vacuum dried for 4 hours to obtain epoxidized modified tributyl citrate.

[0023] B2. Mix the epoxidized tributyl citrate with sodium alginate and stir evenly to form an oil-water emulsion. Then, add the poly (N-isopropylacrylamide) solution and the calcium chloride solution, and stir and react at 45° C. for 4 hours. After the reaction, centrifuge and separate. The precipitate is washed with deionized water and dried for 10 hours to obtain a microcapsule-smart material composite modified tributyl citrate.

[0024] B3. Add tributyl citrate of the microcapsule-smart material composite to a dichloromethane solution, add 2-carboxyethylphenylphosphinic acid and dibutyltin dilaurate as catalysts, and react at 75°C under nitrogen protection for 7 hours. After the reaction is completed, filter, wash the precipitate with deionized water, and dry for 8 hours to obtain modified tributyl citrate with flame retardant, temperature-sensitive regulation and stabilization functions.

[0025] Furthermore, in step B1, the dosage ratio of tributyl citrate, phosphotungstic acid, and hydrogen peroxide solution is 60 g:0.8 g:35 mL; the mass fraction of the hydrogen peroxide solution is 35%; the dropwise addition time of the hydrogen peroxide solution is controlled within 2 h; the stirring speed is 300 r / min; and the vacuum drying conditions are 60° C. and 3 kPa.

[0026] Furthermore, in step B2, the amount ratio of sodium alginate, poly (N-isopropylacrylamide) solution, and calcium chloride solution is 20 g: 12 mL: 15 mL; the mass fraction of sodium alginate is 3%, the mass fraction of poly (N-isopropylacrylamide) solution is 15%, and the concentration of calcium chloride solution is 0.2 mol / L; the stirring speed is 400 r / min; the centrifugal speed is 10,000 r / min, and each centrifugation time is 10 min; the drying temperature is 40°C; in step B3, the amount ratio of dichloromethane solution, 2-carboxyethylphenylphosphinic acid, and dibutyltin dilaurate is 250 mL: 10 g: 0.6 g; and the drying temperature is 50°C.

[0027] Hydrogen peroxide, catalyzed by phosphotungstic acid, epoxidizes the double bonds of tributyl citrate to generate epoxy groups. These groups react with HCl produced by PVC degradation, consuming corrosive gases while also enhancing interfacial interactions with inorganic fillers such as calcium stearate and hydrotalcite through polar groups.

[0028] Epoxidized tributyl citrate acts as the oil phase, emulsified with sodium alginate through high-speed shearing to form an oil-water emulsion. This is then cross-linked with calcium chloride to form alginate microcapsules encapsulating the oil phase. Poly(N-isopropylacrylamide) is introduced as a temperature-sensitive material. Its low critical solution temperature allows the microcapsules to release the plasticizer at the high temperatures of PVC processing, while maintaining structural stability at lower temperatures.

[0029] Using dibutyltin dilaurate as a catalyst, 2-carboxyethylphenylphosphinic acid is grafted onto the hydroxyl groups of tributyl citrate, introducing a phosphorus-carbon bond and a carboxylic acid group. During combustion, the phosphorus-containing groups form a phosphoric acid / pyrophosphate coating, blocking heat and oxygen while simultaneously releasing non-combustible gases to dilute the oxygen in the flame zone.

[0030] A dynamic plasticizing and regulating PVC environmentally friendly stabilizer compounding method specifically comprises the following steps:

[0031] S1. Start the high-speed mixer and stir. Add 20-30 parts of modified calcium stearate, 60-90 parts of hydrotalcite, 12-22 parts of organotin, 4-10 parts of nano-silica, and 3-7 parts of nano-montmorillonite in sequence. Maintain the stirring speed for 5 minutes to achieve uniform dispersion and preliminary compounding of the inorganic powders through mechanical force to avoid agglomeration.

[0032] S2. Increase the stirring speed and sequentially add 50-70 parts of modified tributyl citrate, 18-28 parts of pentaerythritol, 22-32 parts of bio-based fatty acid, 12-16 parts of methyl methacrylate-butadiene-styrene copolymer, and 4-10 parts of stearic acid, and stir for 8 minutes to allow the organic components to form core-shell structure composite particles with the inorganic powder through physical coating;

[0033] S3. Increase the stirring speed again, add 16-22 parts of compound antioxidant, 2-6 parts of graphene quantum dots, 3-6 parts of antistatic agent, and 10-14 parts of phosphorus-containing flame retardant in sequence, maintain the stirring speed for 7 minutes, and strengthen the uniform dispersion of functional additives in the composite system by shear force to complete the multi-component synergistic composite process;

[0034] S4. The mixed material is transferred to a twin-screw extruder. The temperature and screw speed of each section of the twin-screw extruder are set. The material is melt-blended and dynamically sheared in the extruder to achieve full combination of the components at the molecular level. The extrudate is extruded through a circular die and immediately enters a cooling water tank. The material is solidified and pelletized to obtain a multifunctional composite stabilizer product with a core-shell structure.

[0035] Furthermore, in the step S1, the stirring speed is 300-400 r / min; in the step S2, the stirring speed is 500-600 r / min; in the step S3, the stirring speed is 700-800 r / min; in the step S4, the temperature of zone 1 is set to 125-135°C, zone 2 is set to 145-155°C, zone 3 is set to 165-175°C, zone 4 is set to 185-195°C, zone 5 is set to 205-215°C, the die head temperature is 195-205°C, the screw speed is controlled at 200-300 r / min; and the cooling water tank temperature is 5-10°C.

[0036] The present invention provides a dynamic plasticization control type PVC environmentally friendly stabilizer compounding method, which has the following beneficial effects:

[0037] 1. The present invention significantly improves the comprehensive performance of PVC stabilizers by subjecting raw materials such as calcium stearate and tributyl citrate to multi-step modification and multi-component composite formula design. After nano-sizing, zinc oxide loading, and functional composite modification, calcium stearate significantly enhances its thermal stability, effectively inhibiting the degradation and yellowing of PVC during processing. Tributyl citrate, through epoxidation, microencapsulation, and flame retardant modification, combines dynamic plasticization control, temperature-sensitive response, and flame retardant functions. Synergistically acting with various additives, PVC products possess excellent thermal stability, mechanical properties, and long-term weather resistance, meeting the requirements of complex processing processes such as extrusion and injection molding, and broadening the application areas of PVC materials.

[0038] 2. The stabilizer of this invention possesses precise dynamic plasticization control capabilities, enabling real-time adjustment of the fluidity and plasticization efficiency of the PVC melt based on processing temperature and shear rate, thereby avoiding over- or under-plasticization and improving production efficiency and product qualification rates. Furthermore, the stabilizer imparts excellent antistatic, flame-retardant, and chemical-resistant properties to PVC products. In applications such as electronic packaging and building pipes, this can reduce safety hazards caused by static electricity accumulation, extend the product's service life in complex environments, and reduce product losses and replacement costs due to performance deficiencies.

[0039] 3. Through raw material modification and process optimization, this invention improves the performance of PVC stabilizers while effectively controlling production costs. On the one hand, environmentally friendly and relatively inexpensive raw materials such as bio-based fatty acids and nano-montmorillonite replace some traditional additives. On the other hand, a unique composite method simplifies the production process, reducing energy consumption and raw material waste. Compared with traditional PVC stabilizers, the unit production cost of this product is reduced by approximately 15%-20%, while improving performance by over 30%. This allows downstream companies to significantly reduce production costs, enhance market competitiveness, and improve economic benefits while ensuring product quality.

[0040] 4. The present invention strictly adheres to the concept of environmental protection. The stabilizer is completely free of heavy metals such as lead and cadmium, as well as harmful substances such as phthalates, and meets stringent environmental standards at home and abroad. At the same time, the extensive use of bio-based raw materials and the introduction of degradable ingredients reduce dependence on petrochemical resources and reduce the pollution to the environment after product disposal. Compared with traditional PVC products, the PVC material of the present invention can gradually degrade in the natural environment after disposal, effectively reducing "white pollution", providing technical support for the green transformation of the plastics industry, and is of great significance for achieving the coordinated progress of economic development and ecological protection. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the embodiments 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 any creative efforts are within the scope of protection of the present invention.

[0042] Example 1: Preparation of a dynamic plasticizing regulated PVC environmentally friendly stabilizer, the specific steps are as follows:

[0043] S1. Turn on the high-speed mixer and set the initial speed to 300r / min. Add 20 parts of modified calcium stearate, 60 parts of hydrotalcite, 12 parts of organotin, 4 parts of nano-silica and 3 parts of nano-montmorillonite in sequence. Keep stirring at the same speed for 5 minutes to achieve uniform dispersion and preliminary compounding of the inorganic powders through mechanical force to avoid agglomeration.

[0044] S2, increasing the speed to 500r / min, adding 50 parts of modified tributyl citrate, 18 parts of pentaerythritol, 22 parts of castor oil fatty acid, 12 parts of methyl methacrylate-butadiene-styrene copolymer, and 4 parts of stearic acid in sequence, and stirring for 8 minutes to allow the organic components to form core-shell structure composite particles with the inorganic powder through physical coating;

[0045] S3. Increase the speed to 700 r / min, add 16 parts of compound antioxidant, 2 parts of graphene quantum dots, 3 parts of dodecyltrimethylammonium chloride, and 10 parts of triphenyl phosphate in sequence, maintain the speed and stir for 7 minutes, and strengthen the uniform dispersion of the functional additives in the composite system by shear force to complete the multi-component synergistic composite process;

[0046] S4. The mixed material is transferred to a twin-screw extruder. The temperature of each section of the twin-screw extruder is set as follows: zone 1 125°C, zone 2 145°C, zone 3 165°C, zone 4 185°C, zone 5 205°C, the die head temperature is 195°C, and the screw speed is controlled at 200r / min. The material is melt blended and dynamically sheared in the extruder to achieve full combination of the components at the molecular level. The extrudate is extruded through a circular die and immediately enters a cooling water tank at 5°C. The material is solidified and pelletized to obtain a multifunctional composite stabilizer product with a core-shell structure.

[0047] Example 2: Preparation of a dynamic plasticizing regulated PVC environmentally friendly stabilizer, the specific steps are as follows:

[0048] S1. Turn on the high-speed mixer and set the initial speed to 400r / min. Add 30 parts of modified calcium stearate, 90 parts of hydrotalcite, 22 parts of organotin, 10 parts of nano-silica and 7 parts of nano-montmorillonite in sequence. Keep stirring at the same speed for 5 minutes to achieve uniform dispersion and preliminary compounding of the inorganic powders through mechanical force to avoid agglomeration.

[0049] S2. Increase the speed to 600 r / min, add 70 parts of modified tributyl citrate, 28 parts of pentaerythritol, 32 parts of palm kernel oil fatty acid, 16 parts of methyl methacrylate-butadiene-styrene copolymer, and 10 parts of stearic acid in sequence, and stir for 8 minutes to allow the organic components to form core-shell structure composite particles with the inorganic powder through physical coating;

[0050] S3, increasing the speed to 800 r / min, adding 22 parts of compound antioxidant, 6 parts of graphene quantum dots, 6 parts of octadecyltrimethylammonium bromide, and 14 parts of resorcinol tetraphenyl diphosphate in sequence, maintaining the speed and stirring for 7 minutes, and strengthening the uniform dispersion of the functional additives in the composite system by shear force to complete the multi-component synergistic composite process;

[0051] S4. The mixed material is transferred to a twin-screw extruder. The temperature of each section of the twin-screw extruder is set as follows: zone 1 135°C, zone 2 155°C, zone 3 175°C, zone 4 195°C, zone 5 215°C, the die head temperature is 205°C, and the screw speed is controlled at 300r / min. The material is melt blended and dynamically sheared in the extruder to achieve full combination of the components at the molecular level. The extrudate is extruded through a circular die and immediately enters a cooling water tank at 10°C. The material is solidified and pelletized to obtain a multifunctional composite stabilizer product with a core-shell structure.

[0052] Example 3: Preparation of a dynamic plasticizing regulated PVC environmentally friendly stabilizer, the specific steps are as follows:

[0053] S1. Turn on the high-speed mixer and set the initial speed to 350r / min. Add 25 parts of modified calcium stearate, 75 parts of hydrotalcite, 17 parts of organotin, 7 parts of nano-silica and 5 parts of nano-montmorillonite in sequence. Keep stirring at the same speed for 5 minutes to achieve uniform dispersion and preliminary compounding of the inorganic powders through mechanical force to avoid agglomeration.

[0054] S2. Increase the speed to 550 r / min, add 60 parts of modified tributyl citrate, 23 parts of pentaerythritol, 27 parts of palm kernel oil fatty acid, 14 parts of methyl methacrylate-butadiene-styrene copolymer, and 7 parts of stearic acid in sequence, and stir for 8 minutes to allow the organic components to form core-shell structure composite particles with the inorganic powder through physical coating;

[0055] S3, increasing the speed to 750r / min, adding 19 parts of compound antioxidant, 4 parts of graphene quantum dots, 4 parts of octadecyltrimethylammonium bromide, and 12 parts of resorcinol tetraphenyl diphosphate in sequence, maintaining the speed and stirring for 7 minutes, and strengthening the uniform dispersion of the functional additives in the composite system by shear force to complete the multi-component synergistic composite process;

[0056] S4. The mixed material is transferred to a twin-screw extruder. The temperature of each section of the twin-screw extruder is set as follows: zone 1 130°C, zone 2 150°C, zone 3 170°C, zone 4 190°C, zone 5 210°C, the die head temperature is 200°C, and the screw speed is controlled at 250r / min. The material is melt blended and dynamically sheared in the extruder to achieve full combination of the components at the molecular level. The extrudate is extruded through a circular die and immediately enters a cooling water tank at 7°C. The material is solidified and pelletized to obtain a multifunctional composite stabilizer product with a core-shell structure.

[0057] Example 4, preparation of modified calcium stearate, the specific steps are as follows:

[0058] A1. Add 25 g of calcium stearate to 300 mL of an ethanol-water mixed solution with a volume ratio of ethanol to water of 7:3. At the same time, add 5 mL of γ-aminopropyltriethoxysilane coupling agent and ultrasonically disperse for 40 min. Then transfer the dispersion to an autoclave and react at 120°C and 1.5 MPa for 3 h. After the reaction, cool to room temperature and centrifuge at 8000 r / min for 10 min. Wash the precipitate three times with ethanol and vacuum dry at 60°C for 12 h to obtain surface-modified nano-calcium stearate.

[0059] A2. Add the surface-modified nano-calcium stearate to 150 mL of 0.5 mol / L zinc nitrate solution, stir evenly, slowly add 20% sodium hydroxide solution, adjust the pH to 9-10, and react at 50°C for 4 h. After the reaction, filter, wash the precipitate with deionized water until neutral, and vacuum dry at 80°C for 2 h, and then calcine at 400°C for 3 h to obtain zinc oxide-loaded calcium stearate.

[0060] A3. Add zinc oxide-loaded calcium stearate to 200 mL of xylene solution, add 8 g of maleic anhydride and 0.5 g of dibenzoyl peroxide, and under nitrogen protection, stir at 300 r / min at 110 ° C for 5 h; after the reaction, wash the product with acetone and vacuum dry it at 60 ° C and -0.09 MPa for 8 h to obtain functionalized composite modified calcium stearate.

[0061] Example 5, preparation of modified tributyl citrate, the specific steps are as follows:

[0062] B1. Add 60 g of tributyl citrate to a reactor, then add 0.8 g of phosphotungstic acid, and slowly dropwise add 35 mL of a 35% mass fraction hydrogen peroxide solution at 45 ° C. The addition time is controlled within 2 h. After the addition is completed, the temperature is raised to 65 ° C. and stirred at a speed of 300 r / min for 5 h. After the reaction is completed, the product is washed with saturated brine, the organic phase is separated, and vacuum dried at 60 ° C. and 3 kPa for 4 h to obtain epoxidized modified tributyl citrate;

[0063] B2. Mix the epoxidized tributyl citrate with 20 g of 3% sodium alginate and stir evenly to form an oil-water emulsion. Then, add 12 mL of 15% poly (N-isopropylacrylamide) solution and 15 mL of 0.2 mol / L calcium chloride solution. Stir and react at 45°C and 400 r / min for 4 h. After the reaction, centrifuge the product at 10,000 r / min for 10 min. Wash the precipitate with deionized water and dry it at 40°C for 10 h to obtain a microcapsule-smart material composite modified tributyl citrate.

[0064] B3. Add the microcapsule-smart material composite tributyl citrate to 250 mL of dichloromethane solution, add 10 g of 2-carboxyethylphenylphosphinic acid and 0.6 g of dibutyltin dilaurate catalyst, and react at 75 ° C under nitrogen protection for 7 hours; after the reaction is completed, filter, wash the precipitate with deionized water, and dry at 50 ° C for 8 hours to obtain modified tributyl citrate with flame retardant, temperature-sensitive regulation and stabilization functions.

[0065] Comparative Example 1: Preparation of a dynamic plasticizing regulated PVC environmentally friendly stabilizer, the specific steps are as follows:

[0066] The remaining steps remained unchanged, except that the modified calcium stearate in Example 2 was replaced by calcium stearate without any treatment to prepare a dynamic plasticizing controllable PVC environmentally friendly stabilizer.

[0067] Comparative Example 2: Preparation of a dynamic plasticizing regulated PVC environmentally friendly stabilizer, the specific steps are as follows:

[0068] The remaining steps remained unchanged, except that the modified tributyl citrate in Example 2 was replaced by tributyl citrate without any treatment to prepare a dynamic plasticization-controlled PVC environmentally friendly stabilizer.

[0069] Performance Testing

[0070]

[0071]

[0072] The performance test results show that the thermal stability time of Examples 1-3 is 42-45 minutes, which is significantly higher than the 25 minutes of Comparative Example 1 and the 28 minutes of Comparative Example 2; the plasticization peak torque is 26-28 N·m, which is lower than the 33-35 N·m of the Comparative Example; the tensile strength is 45-48 MPa and the elongation at break is 350%-380%, which are both better than the 32-35 MPa and 220%-250% of the Comparative Example; the flame retardant grade reaches UL94V-0, while Comparative Example 1 is V-2 and Comparative Example 2 is HB; the surface resistance is ≤8.5× Ω, meeting the antistatic requirements, while the comparative example did not meet the standards; after 500h of UV aging, the elongation at break retention rate was 88%-92%, much higher than 65%-70% of the comparative example, indicating that the stabilizer of the present invention is significantly superior to the unmodified system in terms of thermal stability, plasticizing properties, mechanical strength, flame retardancy, antistatic properties and weather resistance, and has significant performance advantages.

[0073] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from 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 dynamic plasticizing and regulating PVC environmentally friendly stabilizer, characterized by: The invention comprises the following raw materials in parts by weight: 20-30 parts of modified calcium stearate, 50-70 parts of modified tributyl citrate, 60-90 parts of hydrotalcite, 12-22 parts of organotin, 18-28 parts of pentaerythritol, 16-22 parts of compound antioxidant, 4-10 parts of nano-silicon dioxide, 22-32 parts of bio-based fatty acid, 2-6 parts of graphene quantum dots, 12-16 parts of methyl methacrylate-butadiene-styrene copolymer, 3-6 parts of antistatic agent, 10-14 parts of phosphorus-containing flame retardant, 4-10 parts of stearic acid, and 3-7 parts of nano-montmorillonite.

2. A dynamic plasticizing and regulating PVC environmental stabilizer according to claim 1, characterized in that: The bio-based fatty acid is one of castor oil fatty acid and palm kernel oil fatty acid; the antistatic agent is one of dodecyltrimethylammonium chloride and octadecyltrimethylammonium bromide; the phosphorus-containing flame retardant is one of triphenyl phosphate and resorcinol tetraphenyl diphosphate; the compound antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:

1.

3. The dynamic plasticizing and regulating PVC environmental stabilizer according to claim 1, characterized in that: The modified calcium stearate is specifically prepared in the following steps: A1. Calcium stearate was added to an ethanol-water mixed solution, and γ-aminopropyltriethoxysilane coupling agent was added at the same time. The mixture was ultrasonically dispersed for 40 minutes, and then the dispersion was transferred to an autoclave and stirred for 3 hours. After the reaction, the mixture was cooled to room temperature and centrifuged for 10 minutes. The precipitate was washed with ethanol and vacuum-dried at 60°C for 12 hours to obtain surface-modified nano-calcium stearate. A2. Add the surface-modified nano-calcium stearate to the zinc nitrate solution, stir evenly, slowly add sodium hydroxide solution dropwise, adjust the pH to 10, and stir at 50°C for 4 hours; after the reaction, filter, wash the precipitate with deionized water until neutral, and vacuum dry at 80°C for 2 hours, and then calcine at 400°C for 3 hours to obtain zinc oxide-loaded calcium stearate; A3. Add zinc oxide-loaded calcium stearate to a xylene solution, add maleic anhydride and dibenzoyl peroxide, and stir the mixture at 110°C under nitrogen protection for 5 hours. After the reaction, wash the product with acetone and vacuum dry it for 8 hours to obtain a functionalized composite-modified calcium stearate.

4. The dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 3, characterized in that: In step A1, the amount ratio of calcium stearate, ethanol-water mixed solution, and γ-aminopropyltriethoxysilane coupling agent is 25g:300mL:5mL; the volume ratio of ethanol to water in the ethanol-water mixed solution is 7:3; the reaction conditions in the reactor are 120°C, 1.5MPa, a stirring speed of 400r / min; the centrifugal speed is 8000r / min; and the precipitate is washed three times with ethanol.

5. The dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 3, characterized in that: In step A2, the surface-modified nano-calcium stearate and zinc nitrate solution are used in a ratio of 25 g:150 mL; the concentration of the zinc nitrate solution is 0.5 mol / L; the mass fraction of the sodium hydroxide solution is 20%; and the stirring speed is 400 r / min. In step A3, the xylene solution, maleic anhydride, and dibenzoyl peroxide are used in a ratio of 200 mL:8 g:0.5 g; the stirring speed is 300 r / min; and the vacuum drying conditions are 60° C. and −0.09 MPa.

6. The dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 1, characterized in that: The modified tributyl citrate is specifically prepared in the following steps: B1. Tributyl citrate was added to a reactor, followed by phosphotungstic acid, and hydrogen peroxide solution was slowly added dropwise at 45°C. After the addition was complete, the temperature was raised to 65°C and stirred for reaction for 5 hours. After the reaction was complete, the product was washed with saturated brine, the organic phase was separated, and vacuum dried for 4 hours to obtain epoxidized modified tributyl citrate. B2. Mix the epoxidized tributyl citrate with sodium alginate and stir evenly to form an oil-water emulsion. Then, add the poly (N-isopropylacrylamide) solution and the calcium chloride solution, and stir and react at 45° C. for 4 hours. After the reaction, centrifuge and separate. The precipitate is washed with deionized water and dried for 10 hours to obtain a microcapsule-smart material composite modified tributyl citrate. B3. Add tributyl citrate of the microcapsule-smart material composite to a dichloromethane solution, add 2-carboxyethylphenylphosphinic acid and dibutyltin dilaurate as catalysts, and react at 75°C under nitrogen protection for 7 hours. After the reaction is completed, filter, wash the precipitate with deionized water, and dry for 8 hours to obtain modified tributyl citrate with flame retardant, temperature-sensitive regulation and stabilization functions.

7. The dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 6, characterized in that: In step B1, the dosage ratio of tributyl citrate, phosphotungstic acid, and hydrogen peroxide solution is 60 g:0.8 g:35 mL; the mass fraction of the hydrogen peroxide solution is 35%; the hydrogen peroxide solution addition time is controlled within 2 h; the stirring speed is 300 r / min; and the vacuum drying conditions are 60° C. and 3 kPa.

8. The dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 6, characterized in that: In step B2, the amount ratio of sodium alginate, poly (N-isopropylacrylamide) solution, and calcium chloride solution is 20 g:12 mL:15 mL; the mass fraction of sodium alginate is 3%, the mass fraction of poly (N-isopropylacrylamide) solution is 15%, and the concentration of calcium chloride solution is 0.2 mol / L; the stirring speed is 400 r / min; the centrifugal speed is 10,000 r / min, and each centrifugation time is 10 min; the drying temperature is 40°C; in step B3, the amount ratio of dichloromethane solution, 2-carboxyethylphenylphosphinic acid, and dibutyltin dilaurate is 250 mL:10 g:0.6 g; and the drying temperature is 50°C.

9. A dynamic plasticizing and regulating PVC environmentally friendly stabilizer compounding method, characterized by: The specific steps include: S1. Start the high-speed mixer and stir. Add 20-30 parts of modified calcium stearate, 60-90 parts of hydrotalcite, 12-22 parts of organotin, 4-10 parts of nano-silica, and 3-7 parts of nano-montmorillonite in sequence. Maintain the stirring speed for 5 minutes to achieve uniform dispersion and preliminary compounding of the inorganic powders through mechanical force to avoid agglomeration. S2. Increase the stirring speed and sequentially add 50-70 parts of modified tributyl citrate, 18-28 parts of pentaerythritol, 22-32 parts of bio-based fatty acid, 12-16 parts of methyl methacrylate-butadiene-styrene copolymer, and 4-10 parts of stearic acid, and stir for 8 minutes to allow the organic components to form core-shell structure composite particles with the inorganic powder through physical coating; S3. Increase the stirring speed again, add 16-22 parts of compound antioxidant, 2-6 parts of graphene quantum dots, 3-6 parts of antistatic agent, and 10-14 parts of phosphorus-containing flame retardant in sequence, maintain the stirring speed for 7 minutes, and strengthen the uniform dispersion of functional additives in the composite system by shear force to complete the multi-component synergistic composite process; S4. The mixed material is transferred to a twin-screw extruder. The temperature and screw speed of each section of the twin-screw extruder are set. The material is melt-blended and dynamically sheared in the extruder to achieve full combination of the components at the molecular level. The extrudate is extruded through a circular die and immediately enters a cooling water tank. The material is solidified and pelletized to obtain a multifunctional composite stabilizer product with a core-shell structure.

10. The method for compounding a dynamic plasticizing and regulating PVC environmentally friendly stabilizer according to claim 9, characterized in that: In the step S1, the stirring speed is 300-400 r / min; in the step S2, the stirring speed is 500-600 r / min; in the step S3, the stirring speed is 700-800 r / min; in the step S4, the temperature of zone 1 is set to 125-135°C, zone 2 is set to 145-155°C, zone 3 is set to 165-175°C, zone 4 is set to 185-195°C, zone 5 is set to 205-215°C, the die head temperature is set to 195-205°C, the screw speed is controlled at 200-300 r / min; and the cooling water tank temperature is set to 5-10°C.

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