High-strength antibacterial PVC composite pipe and preparation process thereof

Abstract

This invention relates to a high-strength antibacterial PVC composite pipe and its preparation process, belonging to the field of PVC pipe technology. It comprises the following raw materials in parts by weight: 100 parts PVC resin, 5-15 parts composite antibacterial agent, 10-20 parts modified nano-calcium carbonate, 1-3 parts ACR resin, 1-3 parts compatibilizer, 0.5-1.5 parts lubricant, 1-2 parts anti-aging agent, and 3-5 parts heat stabilizer; the composite antibacterial agent is a mixture of nano-zinc oxide surface-treated with a silane coupling agent and silver-loaded sepiolite, with a mixing mass ratio of (2-4):1. The prepared PVC composite pipe exhibits excellent antibacterial properties and strength.

Description

Technical Field

[0001] This invention belongs to the field of PVC pipe technology, and relates to a high-strength antibacterial PVC composite pipe and its preparation process. Background Technology

[0002] Polyvinyl chloride (PVC) pipes are widely used in various fields due to their excellent chemical corrosion resistance, electrical insulation, flame retardancy and low cost. As the application environment becomes more complex, the functional requirements for PVC pipes are also increasing, especially in terms of antibacterial properties and mechanical strength.

[0003] In terms of antibacterial modification, existing technologies mainly employ the addition of organic or inorganic antibacterial agents. While organic antibacterial agents offer immediate effectiveness, they suffer from poor heat resistance, easy migration and precipitation, and short service life, making them unsuitable for the high-temperature environment and long-term use requirements of PVC processing. Inorganic antibacterial agents also have significant shortcomings in practical applications: First, the carriers are mostly spherical or granular materials, resulting in weak interfacial bonding with the PVC matrix, and excessive addition can significantly reduce the mechanical properties of the pipe. Second, silver-based antibacterial agents are easily reduced and discolored under the high temperatures and light exposure conditions of PVC processing, affecting the product's appearance. Third, antibacterial agents exhibit poor dispersibility in the matrix, easily agglomerating, leading to uneven antibacterial effects and poor stability.

[0004] To improve the ring stiffness and resistance to external pressure of PVC pipes, traditional methods often involve increasing the wall thickness or adding a sand-filled layer. However, increasing the wall thickness increases material costs, while the sand-filled layer is prone to stress concentration points due to the poor compatibility between sand particles and PVC resin, resulting in weak interlayer bonding and easy delamination after long-term use.

[0005] Therefore, there is an urgent need to develop a PVC composite pipe that combines high strength and long-lasting antibacterial properties. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength antibacterial PVC composite pipe and its preparation process. The prepared PVC composite pipe has excellent antibacterial properties and strength.

[0007] The objective of this invention can be achieved through the following technical solutions: A high-strength antibacterial PVC composite pipe, wherein the PVC composite pipe comprises the following parts by weight of raw materials: 100 parts PVC resin, 5-15 parts composite antibacterial agent, 10-20 parts modified nano calcium carbonate, 1-3 parts ACR resin, 1-3 parts compatibilizer, 0.5-1.5 parts lubricant, 1-2 parts anti-aging agent and 3-5 parts heat stabilizer; The composite antibacterial agent is a mixture of nano zinc oxide surface-treated with silane coupling agent and silver-loaded sepiolite, with a mixing mass ratio of (2~4):1.

[0008] As a preferred embodiment of the present invention, the preparation process of the composite antibacterial agent is as follows: S21. Add activated sepiolite powder to a reaction vessel, add deionized water at a solid-liquid ratio of 1:5 and stir to disperse. Add the prepared silver ammonia solution dropwise to the sepiolite suspension and adjust the pH to 7.0~8.0. Stir at a constant temperature of 40~60℃ for 4~6h. Add 1~2% glucose by weight of sepiolite, heat to 70~80℃ and stir for 30min. Wash with deionized water and anhydrous ethanol, dry at 80~100℃, and then calcine at 250~300℃ for 1~2h. S22. Mix nano zinc oxide with silane coupling agent and ethanol solution at a mass ratio of 1:20, reflux and stir at 65~75℃ for 3~5h, wash and dry after the reaction to obtain modified nano zinc oxide. S23. The modified nano zinc oxide and modified sepiolite are ball-milled and mixed for 30 minutes to obtain the composite antibacterial agent.

[0009] As a preferred embodiment of the present invention, the preparation process of the modified nano-calcium carbonate is as follows: Nano-calcium carbonate was dried at 110℃ for 1 hour, and then 2.5-4% stearic acid and 2-4% aluminate were added by weight of calcium carbonate. The mixture was stirred at 1000 rpm for 15 minutes at 90-95℃ to obtain the modified nano-calcium carbonate.

[0010] As a preferred embodiment of the present invention, the lubricant is one or more of calcium stearate, paraffin wax, erucamide, Fischer-Tropsch wax, polyethylene wax, and oxidized polyethylene wax.

[0011] As a preferred embodiment of the present invention, the anti-aging agent is one of methylbutyridine and dioctadecyl thiodipropionate.

[0012] As a preferred embodiment of the present invention, the compatibilizer is chlorinated polyethylene or maleic anhydride-grafted ABS.

[0013] As a preferred embodiment of the present invention, the heat stabilizer is one or more of butyltin stabilizer, thiol methyltin stabilizer, and metal carboxylates.

[0014] As a preferred embodiment of the present invention, the specific preparation process of the activated sepiolite powder is as follows: Sepiolite was crushed to 200 mesh and added to deionized water at a solid-liquid ratio of 1:10. The mixture was stirred to form a suspension. 0.5-1.0% sodium hexametaphosphate by weight of the sepiolite was added and stirred for 30 minutes. Then, dilute hydrochloric acid was added to adjust the pH to 3.0-4.0. The mixture was then heated to 60-80℃ and stirred for 1-2 hours. After filtration, washing, drying at 105℃, and grinding through a 400-mesh sieve, activated sepiolite was obtained.

[0015] A manufacturing process for a high-strength antibacterial PVC composite pipe includes the following steps: S1. According to the mass fraction, put each raw material into a high-speed mixer, heat to 110~120℃, stir at 1000~1200r / min for 15~25min, and after mixing, cool down by 40~50℃. S2. The mixed materials are poured into the hopper of a twin-screw extruder for melt extrusion, shaping, cooling and cutting to obtain the PVC pipe.

[0016] As a preferred technical solution of the present invention, in step S2, the heating zone temperature of the twin-screw extruder barrel is: zone 1 160~165℃, zone 2 165~170℃, zone 3 170~175℃, zone 4 175~180℃, and zone 5 185~190℃.

[0017] In this invention, calcium carbonate is treated with stearic acid and aluminate. When used together, the coupling effect of aluminate can compensate for the insufficient binding force of stearic acid relying solely on physical coating. Stearic acid prevents agglomeration, while aluminate enhances binding force. Together, they provide excellent interfacial bonding, thereby reducing microcracks caused by filler-resin separation and delaying material aging. Furthermore, the treated nano-calcium carbonate exhibits good compatibility with the composite antibacterial agent, preventing direct contact and agglomeration between antibacterial particles, thus maintaining a long-lasting and stable antibacterial rate.

[0018] Sepiolite is first acid-activated by adding sodium hexametaphosphate to further enhance the activation process, thereby increasing its specific surface area and the number of silanol groups. Silver ammonia complex ion [Ag(NH3)2] + It is stable in a weakly alkaline environment and carries a positive charge, making it easily adsorbed by the negatively charged surface of sepiolite; glucose, as a mild reducing agent, can reduce Ag... + The silver is reduced to nano-silver, and then calcined to stabilize the crystal structure, while simultaneously removing residual Ag. + Thermal reduction yields nano-silver, enhancing the binding force between silver and the carrier. Silver-loaded sepiolite: Ag + Slow release from sepiolite nanopores provides long-lasting, broad-spectrum antibacterial properties.

[0019] Nano zinc oxide itself has antibacterial activity, and it is compatible with Ag. +A synergistic effect is generated, which improves antibacterial efficiency while reducing the amount of silver used. The nano zinc oxide is also treated with a coupling agent. After the two are mixed, they are evenly dispersed in PVC without agglomeration.

[0020] Therefore, the composite antibacterial agent used in this invention, as a key functional component for antibacterial action, endows the pipe with efficient, long-lasting, and broad-spectrum antibacterial properties. The fiber reinforcement of sepiolite and the rigid particle reinforcement of nano-zinc oxide work synergistically to improve the pipe's ring stiffness, impact resistance, and overall strength of the PVC pipe. Both components exhibit good compatibility with PVC and are uniformly dispersed, ensuring melt stability and uniform layer thickness during co-extrusion. The fibrous nanoporous structure of sepiolite physically confines silver ions, achieving Ag... + The slow, controlled release of nano-zinc oxide further delays the migration of silver ions. The synergistic effect of these two components matches the antibacterial duration with the pipeline's lifespan, solving the problems of easy loss and short antibacterial period associated with traditional silver-based antibacterial agents.

[0021] The beneficial effects of this invention are: This invention designs an antibacterial system by combining fibrous silver-loaded sepiolite with nano zinc oxide, and combines the enhancement of nano calcium carbonate with the synergistic effect of other components to achieve simultaneous improvement in antibacterial properties and mechanical strength of PVC pipes. This solves the problems of poor compatibility between antibacterial agents and matrix, short antibacterial time and weak mechanical properties in the prior art. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0023] It should be noted that in the following embodiments, the PVC resin was purchased from China Petrochemical Corporation, with the grade S-1000; the ACR resin was purchased from Ningbo Laitong New Material Technology Co., Ltd., with the grade LP-23; unless otherwise specified, the present invention does not specifically limit the source of other raw materials used, and products prepared by commercially available products or conventional preparation methods well known to those skilled in the art can be used. Experimental methods without specific conditions are all conventional methods and conditions well known in the art. Example 1

[0024] Preparation of compound antibacterial agents: S21. Crush sepiolite to 200 mesh, add deionized water at a solid-liquid ratio of 1:10, stir to form a suspension, add 0.8% sodium hexametaphosphate by weight of sepiolite, stir for 30 min, add dilute hydrochloric acid, adjust the pH to 3.0~4.0; then heat to 60~80℃, stir for 1~2 h, filter, wash, dry at 105℃, grind through a 400 mesh sieve to obtain activated sepiolite; Activated sepiolite powder was added to a reaction vessel, and deionized water was added at a solid-liquid ratio of 1:5 and stirred to disperse. The prepared silver ammonia solution was added dropwise to the sepiolite suspension, and the pH was adjusted to 7.0~8.0. The mixture was stirred at a constant temperature of 50℃ for 5 hours, and 1~2% glucose (by weight of sepiolite) was added. The mixture was heated to 75℃ and stirred for 30 minutes. The mixture was washed with deionized water and anhydrous ethanol, dried at 90℃ for 8 hours, and then calcined at 280℃ for 1.5 hours. S22. Mix nano zinc oxide with silane coupling agent and ethanol solution at a mass ratio of 1:20, reflux and stir at 70°C for 4 hours, wash and dry after the reaction to obtain modified nano zinc oxide. S23. Modified nano zinc oxide and modified sepiolite in a mass ratio of 3:1 are ball-milled and mixed for 30 minutes to obtain the composite antibacterial agent.

[0025] Modified nano-calcium carbonate: Nano-calcium carbonate was dried at 110℃ for 1 hour, and then 3.5% stearic acid and 3% aluminate by weight of calcium carbonate were added. The mixture was stirred at 1000 rpm for 15 minutes at 95℃ to obtain the modified nano-calcium carbonate.

[0026] Preparation of high-strength antibacterial PVC composite pipes: S1. According to the mass fractions, put 100 parts of PVC resin, 11 parts of composite antibacterial agent, 14 parts of modified nano calcium carbonate, 2 parts of ACR resin, 2 parts of maleic anhydride grafted ABS, 1 part of calcium stearate, 1.5 parts of dioctadecyl thiodipropionate and 4 parts of butylstannic acid into a high-speed mixer, heat to 115℃, stir at 1100r / min for 20min, and after mixing, cool down to 45℃. S2. Pour the mixed material into the hopper of a twin-screw extruder for melt extrusion, shaping, cooling and cutting to obtain the PVC pipe. The heating zone temperature of the twin-screw extruder barrel is: Zone 1 163℃, Zone 2 168℃, Zone 3 174℃, Zone 4 177℃, Zone 5 188℃. Example 2

[0027] Preparation of compound antibacterial agents: S21. Crush sepiolite to 200 mesh, add deionized water at a solid-liquid ratio of 1:10, stir to form a suspension, add 0.5% sodium hexametaphosphate by weight of sepiolite, stir for 30 min, add dilute hydrochloric acid, adjust the pH to 3.0~4.0; then heat to 70℃, stir for 2 h, filter, wash, dry at 105℃ for 10 h, grind through a 400 mesh sieve to obtain activated sepiolite; Activated sepiolite powder was added to a reaction vessel, and deionized water was added at a solid-liquid ratio of 1:5 and stirred to disperse. The prepared silver ammonia solution was added dropwise to the sepiolite suspension, and the pH was adjusted to 7.0~8.0. The mixture was stirred at a constant temperature of 40℃ for 6 hours, and 1% glucose (by weight of sepiolite) was added. The mixture was heated to 70℃ and stirred for 30 minutes. The mixture was washed with deionized water and anhydrous ethanol, dried at 80℃ for 15 hours, and then calcined at 250℃ for 2 hours. S22. Mix nano zinc oxide with silane coupling agent and ethanol solution at a mass ratio of 1:20, reflux and stir at 70°C for 5 hours, wash and dry after the reaction to obtain modified nano zinc oxide. S23. Modified nano zinc oxide and modified sepiolite in a mass ratio of 2:1 are ball-milled and mixed for 30 minutes to obtain the composite antibacterial agent.

[0028] Modified nano-calcium carbonate: Nano-calcium carbonate was dried at 110℃ for 1 hour, and then 2.5% stearic acid and 2% aluminate by weight of calcium carbonate were added. The mixture was stirred at 1000 rpm for 15 minutes at 90℃ to obtain the modified nano-calcium carbonate.

[0029] Preparation of high-strength antibacterial PVC composite pipes: S1. According to the mass fractions, put 100 parts of PVC resin, 5 parts of composite antibacterial agent, 10 parts of modified nano calcium carbonate, 1 part of ACR resin, 1 part of maleic anhydride grafted ABS, 0.5 parts of calcium stearate, 1 part of dioctadecyl thiodipropionate and 3 parts of butylstannic acid into a high-speed mixer, heat to 110℃, stir at 1000r / min for 15min, and after mixing, cool down by 40℃. S2. Pour the mixed material into the hopper of a twin-screw extruder for melt extrusion, shaping, cooling and cutting to obtain the PVC pipe. The heating zone temperature of the twin-screw extruder barrel is: Zone 1 160℃, Zone 2 165℃, Zone 3 170℃, Zone 4 175℃, Zone 5 185℃. Example 3

[0030] Preparation of compound antibacterial agents: S21. Crush sepiolite to 200 mesh, add deionized water at a solid-liquid ratio of 1:10, stir to form a suspension, add 1.0% sodium hexametaphosphate by weight of sepiolite, stir for 30 min, add dilute hydrochloric acid, adjust the pH to 3.0~4.0; then heat to 80℃, stir for 2 h, filter, wash, dry at 105℃ for 10 h, grind through a 400 mesh sieve to obtain activated sepiolite; Activated sepiolite powder was added to a reaction vessel, and deionized water was added at a solid-liquid ratio of 1:5 and stirred to disperse. The prepared silver ammonia solution was added dropwise to the sepiolite suspension, and the pH was adjusted to 7.0~8.0. The mixture was stirred at a constant temperature of 60℃ for 6 hours, and 2% glucose (by weight of sepiolite) was added. The temperature was raised to 80℃ and stirred for 30 minutes. The mixture was washed with deionized water and anhydrous ethanol, dried at 100℃ for 10 hours, and then calcined at 300℃ for 2 hours. S22. Mix nano zinc oxide with silane coupling agent and ethanol solution at a mass ratio of 1:20, reflux and stir at 75°C for 5 hours, wash and dry after the reaction to obtain modified nano zinc oxide. S23. The modified nano zinc oxide and modified sepiolite in a mass ratio of 4:1 are ball-milled and mixed for 30 minutes to obtain the composite antibacterial agent.

[0031] Modified nano-calcium carbonate: Nano-calcium carbonate was dried at 110°C for 1 hour, and then 4% stearic acid and 4% aluminate (by weight of calcium carbonate) were added. The mixture was stirred at 1000 rpm for 15 minutes at 95°C to obtain the modified nano-calcium carbonate.

[0032] Preparation of high-strength antibacterial PVC composite pipes: S1. According to the mass fractions, put 100 parts of PVC resin, 15 parts of composite antibacterial agent, 20 parts of modified nano calcium carbonate, 3 parts of ACR resin, 3 parts of maleic anhydride grafted ABS, 1.5 parts of calcium stearate, 2 parts of dioctadecyl thiodipropionate and 5 parts of butyl stannic acid into a high-speed mixer, heat to 120℃, stir at 1200r / min for 25min, and after mixing, cool down by 50℃. S2. Pour the mixed material into the hopper of a twin-screw extruder for melt extrusion, shaping, cooling and cutting to obtain the PVC pipe. The heating zone temperature of the twin-screw extruder barrel is: Zone 1 165℃, Zone 2 170℃, Zone 3 175℃, Zone 4 180℃, Zone 5 190℃.

[0033] Comparative Example 1 It is basically the same as Example 1, except that the calcium carbonate in Comparative Example 1 was not modified.

[0034] Comparative Example 2 It is basically the same as Example 1, except that modified zinc oxide was not added to the composite antibacterial agent in Comparative Example 2.

[0035] Comparative Example 3 It is basically the same as Example 1, except that the sepiolite in the composite antibacterial agent in Comparative Example 3 has not been modified.

[0036] Comparative Example 4 The results are basically the same as in Example 1, except that the composite antibacterial agent in Comparative Example 4 was prepared by ball milling and mixing nano zinc oxide with sepiolite in a mass ratio of (2~4):1 for 30 minutes.

[0037] Performance testing 1. Antibacterial properties: The PVC pipes prepared in the examples and comparative examples were tested for antimicrobial properties according to the QB / T2591-2003 test method and standard. Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were selected as indicator bacteria, respectively. The data obtained are shown in Table 1 below: Table 1 2. Tensile strength: Refer to GB / T 8804.2-2016; 3. Impact strength: Referring to GB / T 1043-2008, the data obtained are shown in Table 2 below: Table 2 Based on the above data, it can be seen that the PVC pipe prepared by this invention has excellent strength and antibacterial properties.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-strength antibacterial PVC composite pipe, characterized in that, The PVC composite pipe comprises the following parts by weight of raw materials: 100 parts PVC resin, 5-15 parts composite antibacterial agent, 10-20 parts modified nano calcium carbonate, 1-3 parts ACR resin, 1-3 parts compatibilizer, 0.5-1.5 parts lubricant, 1-2 parts anti-aging agent and 3-5 parts heat stabilizer; The composite antibacterial agent is a mixture of nano zinc oxide surface-treated with silane coupling agent and silver-loaded sepiolite, with a mixing mass ratio of (2~4):

1.

2. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The preparation process of the composite antibacterial agent is as follows: S21. Add activated sepiolite powder to a reaction vessel, add deionized water at a solid-liquid ratio of 1:5 and stir to disperse. Add the prepared silver ammonia solution dropwise to the sepiolite suspension and adjust the pH to 7.0~8.

0. Stir at a constant temperature of 40~60℃ for 4~6h. Add 1~2% glucose by weight of sepiolite, heat to 70~80℃ and stir for 30min. Wash with deionized water and anhydrous ethanol, dry at 80~100℃, and then calcine at 250~300℃ for 1~2h. S22. Mix nano zinc oxide with silane coupling agent and ethanol solution at a mass ratio of 1:20, reflux and stir at 65~75℃ for 3~5h, wash and dry after the reaction to obtain modified nano zinc oxide. S23. The modified nano zinc oxide and modified sepiolite are ball-milled and mixed for 30 minutes to obtain the composite antibacterial agent.

3. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The preparation process of the modified nano-calcium carbonate is as follows: Nano-calcium carbonate was dried at 110℃ for 1 hour, and then 2.5-4% stearic acid and 2-4% aluminate were added by weight of calcium carbonate. The mixture was stirred at 1000 rpm for 15 minutes at 90-95℃ to obtain the modified nano-calcium carbonate.

4. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The lubricant is one or more of calcium stearate, paraffin wax, erucamide, Fischer-Tropsch wax, polyethylene wax, and oxidized polyethylene wax.

5. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The anti-aging agent is one of methylbutyridine and dioctadecyl thiodipropionate.

6. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The compatibilizer is chlorinated polyethylene or maleic anhydride-grafted ABS.

7. The high-strength antibacterial PVC composite pipe according to claim 1, characterized in that, The heat stabilizer is one or more of butyltin stabilizer, thiol methyltin stabilizer, and metal carboxylates.

8. The high-strength antibacterial PVC composite pipe according to claim 2, characterized in that, The specific preparation process of the activated sepiolite powder is as follows: Sepiolite was crushed to 200 mesh and added to deionized water at a solid-liquid ratio of 1:

10. The mixture was stirred to form a suspension. 0.5-1.0% sodium hexametaphosphate by weight of the sepiolite was added and stirred for 30 minutes. Then, dilute hydrochloric acid was added to adjust the pH to 3.0-4.

0. The mixture was then heated to 60-80℃ and stirred for 1-2 hours. After filtration, washing, drying at 105℃, and grinding through a 400-mesh sieve, activated sepiolite was obtained.

9. A manufacturing process for a high-strength antibacterial PVC composite pipe as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. According to the mass fraction, put each raw material into a high-speed mixer, heat to 110~120℃, stir for 15~25min at 1000~1200r / min, and cool down by 40~50℃ after mixing. S2. The mixed materials are poured into the hopper of a twin-screw extruder for melt extrusion, shaping, cooling and cutting to obtain the PVC pipe.

10. The preparation process of the high-strength antibacterial PVC composite pipe according to claim 9, characterized in that, In step S2, the heating zone temperatures of the twin-screw extruder barrel are: Zone 1 160~165℃, Zone 2 165~170℃, Zone 3 170~175℃, Zone 4 175~180℃, and Zone 5 185~190℃.

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