Modified chlorite toughened antifouling PVC pipe and preparation method thereof

Abstract

The invention discloses a modified chlorite toughened antifouling PVC pipe and a preparation method thereof, and belongs to the technical field of PVC pipes. The PVC pipe comprises the following raw materials: 70-80% of PVC resin, 0.2-2% of a heat stabilizer, 1-5% of a lubricant, 5-10% of an impact modifier, 1-2% of an antioxidant and 3-10% of an anti-fouling toughening modifier. On one hand, the invention overcomes the contradiction that toughening and strengthening are difficult to balance and the function and durability are difficult to balance in the traditional modification technology, and on the other hand, compared with the traditional chemical antifouling agent which depends on organic tin, heavy metal salt and the like and possibly causes negative influence on the environment, the curcumin which is naturally sourced is selected as an active component, and the environmental friendliness is better. In addition, according to the technology, multiple functions of strengthening, toughening and antifouling are integrated in one modifier, the formula and the production process are simplified, and the use of other expensive additives can be possibly reduced.

Description

Technical Field

[0001] This invention belongs to the field of PVC pipe technology, and relates to a modified chlorite toughened and antifouling PVC pipe and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) pipes are widely used in water supply and drainage, construction, and agricultural irrigation due to their excellent corrosion resistance, high mechanical strength, and low cost. However, traditional PVC materials themselves lack toughness, and are prone to brittle fracture, especially at low temperatures or under impact, affecting their reliability and lifespan. Furthermore, when transporting eutrophic water or sewage, PVC pipes are susceptible to the adhesion and growth of microorganisms and algae, forming difficult-to-remove biofouling that leads to pipe blockage, reduced transport efficiency, and high maintenance costs.

[0003] To address the aforementioned issues, conventional toughening modification methods (such as adding elastomers) often sacrifice material rigidity and strength while improving toughness. Regarding antifouling, traditional methods involving the addition of chemical bactericides or surface coatings suffer from problems such as easy loss of antifouling components, poor durability, and potential environmental toxicity. For example, CN202010323371.9 discloses an impact-resistant toughened PVC pipe fitting and its preparation method. By adding elastomer particles with impact modifiers such as MBS-66, the total crazing-inducing stress can be reduced. Furthermore, the particle's own deformation and shear bands prevent the growth of crazing and absorb the impact energy transmitted into the material, thereby achieving impact resistance and toughening.

[0004] In terms of antifouling and antibacterial properties, curcumin is a natural polyphenolic compound extracted from turmeric, exhibiting excellent antibacterial, antioxidant, and pH-sensitive properties (yellow under acidic / neutral conditions, turning reddish-brown under alkaline conditions). For example, CN201610605348.2 discloses a paint antifouling additive that combines components with biofouling effects, such as capsaicin / capsaicin, curcumin, garlic powder, and artemisinin, with the addition of slow-release agents and oily solvents. This allows the additive to achieve good and long-lasting antifouling effects while also being uniformly dispersed and mixed with various anti-corrosion paints, offering advantages such as good performance, long duration, good dispersibility, and environmental friendliness. However, curcumin molecules are prone to photodegradation, and the direct application of curcumin is limited by its poor photochemical stability, presenting a technical bottleneck.

[0005] Therefore, developing a composite modification technology that can effectively improve the toughness and strength of PVC pipes while enhancing their anti-fouling performance has become an urgent technological need for the industry. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a modified chlorite-toughened and stain-resistant PVC pipe and its preparation method.

[0007] Specifically, this is achieved through the following technical solutions: A modified chlorite-toughened and stain-resistant PVC pipe, by mass fraction, comprises the following raw materials: 70-80% PVC resin, 0.2-2% heat stabilizer, 1-5% lubricant, 5-10% impact modifier, 1-2% antioxidant, and 3-10% stain-resistant and toughening modifier; The antifouling and toughening modifier is obtained by polymer-modified curcumin intercalation into chlorite.

[0008] Furthermore, the antifouling toughening modifier is prepared by the following method: a. Chlorite exfoliation: Chlorite mineral is ground into powder and dispersed in organic acid at a solid-liquid mass ratio of 1:10 to 1:20. The mixture is heated and stirred in a water bath at 60-80℃ for 6-24 hours. Then, solid-liquid separation is performed, the solid product is collected and washed with deionized water until neutral, and dried to obtain exfoliated chlorite. b. Intercalation modification: The polymer-modified curcumin is dissolved in water, and the exfoliated chlorite obtained in step a is dispersed in the solution. The mixture is subjected to ultrasonic treatment for 6-24 hours under heating conditions of 40-60℃. After the reaction is completed, solid-liquid separation is performed, the solid product is collected, and after washing, drying and grinding, the antifouling toughening modifier is obtained.

[0009] Furthermore, in step b, the mass ratio of polymer-modified curcumin to exfoliated chlorite is 3~6:1, and the mass ratio of the total mass of the mixture obtained by adding polymer-modified curcumin and exfoliated chlorite to the mass of solvent water is 1:10~1:20.

[0010] Furthermore, the organic acid is one of oxalic acid and citric acid, with a concentration of 1 mol / L.

[0011] Further, the polymer-modified curcumin is prepared by the following steps: curcumin and polymer are heated at 90-100 °C. o Dissolve in water at temperature C, mix and stir well, then place in an oven to dry at 40~60°C. o C, allowing the water to evaporate completely, yields polymer-modified curcumin.

[0012] Furthermore, the polymer is polyvinyl alcohol, which has the property of decomposing under water-soluble conditions.

[0013] A method for preparing modified chlorite-toughened and stain-resistant PVC pipe includes the following steps: (1) Ingredients: Weigh each component according to the following mass fractions: 70-80% PVC resin, 0.2-2% heat stabilizer, 1-5% lubricant, 5-10% impact modifier, 1-2% antioxidant, 3-10% antifouling and toughening modifier, and divide the antifouling and toughening modifier into two portions for later use, one of which accounts for 60%; (2) Segmented mixing: Mix all components except the antifouling and toughening modifier evenly, then add 60% of the total amount of the antifouling and toughening modifier to the mixture, mix evenly to obtain mixture 1, ultrasonically treat for 2-4 hours, then add the remaining antifouling and toughening modifier, and stir evenly. (3) Molding and processing: Add the auxiliary materials required for molding to the above-mentioned uniformly mixed materials, and obtain the modified chlorite toughened and antifouling PVC pipe by extrusion molding process.

[0014] Furthermore, the heat stabilizer is one or more of butyltin stabilizer, thiol methyltin stabilizer, zeolite, and C6-C12 metal carboxylates.

[0015] Furthermore, the lubricant is one or more of calcium stearate, paraffin wax, erucamide, Fischer-Tropsch wax, polyethylene wax, and oxidized polyethylene wax.

[0016] Furthermore, the impact modifier is one or more of methyl methacrylate-butadiene-styrene copolymer (MBS), chlorinated polyethylene (CPE), acrylate rubber (ACR), and acrylonitrile-butadiene-styrene copolymer (ABS).

[0017] Furthermore, the antioxidant includes one or more of antioxidant 1010, antioxidant 300, antioxidant 264, antioxidant 2246, and antioxidant 1076.

[0018] The technical principle of this invention is based on the integrated design of "structure-function" and the synergistic effect of natural active substances. Its core lies in the preparation and application of a unique "polymer-modified curcumin-intercalated chlorite" composite modifier, achieving synergistic modification of PVC materials from both physical structure and chemical function perspectives. First, the natural layered silicate mineral—chlorite—is acid-treated to exfoliate its layers, exposing a large specific surface area and abundant active sites. Subsequently, under ultrasonic treatment, polymer-modified curcumin is inserted and anchored between the chlorite layers. When this composite modifier is dispersed in the PVC matrix, the exfoliated chlorite layers act as a nanoscale rigid reinforcement, effectively hindering crack propagation and dispersing stress. Furthermore, its large specific surface area allows for strong interfacial interactions with the PVC molecular chains, thereby significantly improving the material's toughness while enhancing its rigidity and strength, achieving a synergistic effect of "toughening" and "strengthening" that is usually difficult to achieve simultaneously. In terms of long-lasting antifouling function, this system works synergistically through a dual mechanism: First, chemical slow-release antibacterial properties. After polymer coating enhances the photothermal stability of curcumin, it is intercalated between chlorite layers. Utilizing chlorite as a "molecular warehouse," curcumin is slowly and controllably released throughout the entire service life of the PVC pipe via ion exchange or concentration gradient diffusion, thus forming an antibacterial microenvironment at the pipe wall interface, inhibiting initial microbial adhesion and biofilm formation. Second, physical surface modification. Leveraging the introduced polymer-modified curcumin and the hydrophilic properties of chlorite itself, the microscopic chemical properties of the PVC pipe's inner wall are altered, enhancing surface hydrophilicity and forming a physical antifouling barrier that discourages the adhesion of hydrophobic microorganisms, creating a synergistic antifouling effect with the chemical antibacterial mechanism. Furthermore, the polymer coating of curcumin provides a primary physical protective layer, effectively isolating it from adverse factors such as high temperatures, strong shear during processing, and ultraviolet radiation in the operating environment, ensuring the functional components maintain their activity and durability during processing and service.

[0019] Beneficial effects Compared to traditional PVC pipe modification technologies, this invention overcomes the inherent contradictions of balancing toughness and strength, as well as functionality and durability. Existing technologies typically use the addition of a single elastomer (such as CPE) for toughening, which often leads to a decrease in material modulus and strength; or the addition of rigid fillers for reinforcement, which increases brittleness. The composite modifier of this invention achieves simultaneous improvement in toughness and strength through the reinforcement and bridging effect of chlorite nanosheets. Simultaneously, the antifouling component (curcumin) is fixed through intercalation chemical bonding, avoiding the problems of easy migration, rapid loss, and short shelf life of antifouling agents in conventional blending or coating methods, ensuring long-lasting antifouling performance. Furthermore, compared to traditional chemical antifouling agents that rely on organotin compounds and heavy metal salts, which may have negative environmental impacts, this invention uses naturally derived curcumin as the active ingredient, making it more environmentally friendly. In addition, this technology integrates multiple functions such as reinforcement, toughening, and antifouling into a single modifier, simplifying the formulation and production process and potentially reducing the use of other expensive additives. Furthermore, by utilizing the dual protection mechanism of polymers providing primary physical protection for curcumin and the layered structure of chlorite, the chemical stability and weather resistance of the functional components during processing and use are greatly enhanced. This effectively isolates them from adverse factors such as light, heat, and strong alkalis, ensuring their chemical activity and stability during processing and storage. Ultimately, this ensures the long-term reliability of the product's performance, providing a solid guarantee for the industrial application of high-performance PVC pipes. Attached Figure Description

[0020] Figure 1 This refers to the water contact angle in Example 1.

[0021] Figure 2 The water contact angle is shown in Comparative Example 4. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0023] The following describes some of the raw materials used in the embodiments and comparative examples of this invention: PVC resin, model P-450, purchased from Shanghai Chlor-Alkali Chemical Co., Ltd. Curcumin, purchased from Zhongshan Dixing Chemical Co., Ltd. Chlorite, purchased from Hebei Kewode Chemical Co., Ltd. Polyvinyl alcohol, purchased from Hebei Zesu Chemical Technology Co., Ltd.; The heat stabilizer was butyltin stabilizer, purchased from Shandong Qiansheng Chemical Co., Ltd. The lubricant was calcium stearate, purchased from Shandong Junteng Chemical Co., Ltd. The impact modifier was chlorinated polyethylene, purchased from Tianjin Zhongke New Materials Co., Ltd. The antioxidant was antioxidant 1010, purchased from Hebei Chuangzhiyuan Biotechnology Co., Ltd. All other raw materials not mentioned are common in the field. The above description is for illustrative purposes only and should not be construed as a strict limitation of the invention. Those skilled in the art can directly purchase commercially available materials or prepare similar or identical materials themselves. These details will not be elaborated upon in the embodiments.

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 A method for preparing modified chlorite-toughened and stain-resistant PVC pipe includes the following steps: (1) Ingredients: Weigh each component according to the following mass fractions: 75% PVC resin, 1% butyltin stabilizer, 3% calcium stearate, 10% chlorinated polyethylene, 1% antioxidant 1010, and 7% antifouling toughening modifier. Divide the antifouling toughening modifier into two portions for later use, one of which accounts for 60%. (2) Segmented mixing: Mix all components except the antifouling and toughening modifier evenly, then add 60% of the total amount of the antifouling and toughening modifier to the mixture, mix evenly to obtain mixture 1, ultrasonically treat for 3 hours, then add the remaining antifouling and toughening modifier, and stir evenly. (3) Molding process: Add 3% by mass of the auxiliary materials required for molding to the above-mentioned uniformly mixed materials, and obtain the modified chlorite toughened antifouling PVC pipe by extrusion molding process.

[0026] The preparation method of the antifouling and toughening modifier is as follows: a. Chlorite exfoliation: Chlorite mineral is ground into powder and dispersed in citric acid at a solid-liquid mass ratio of 1:10. The mixture is heated in a water bath at 60°C and stirred for 6 hours. Then, solid-liquid separation is performed, the solid product is collected and washed with deionized water until neutral, and dried to obtain exfoliated chlorite. b. Intercalation modification: Polymer-modified curcumin is dissolved in water, and the exfoliated chlorite obtained in step a is dispersed in the solution. The mixture is ultrasonically treated for 6 hours under heating at 40°C. After the reaction is completed, solid-liquid separation is performed, the solid product is collected, and after washing, drying and grinding, the antifouling toughening modifier is obtained.

[0027] Example 2 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the method for preparing the antifouling and toughening modifier is different.

[0028] The preparation method of the antifouling and toughening modifier in this embodiment is as follows: a. Chlorite exfoliation: Chlorite mineral is ground into powder and dispersed in oxalic acid at a solid-liquid mass ratio of 1:20. The mixture is heated in a water bath at 80°C and stirred for 24 hours. Then, solid-liquid separation is performed, the solid product is collected and washed with deionized water until neutral, and dried to obtain exfoliated chlorite. b. Intercalation modification: Polymer-modified curcumin is dissolved in water, and the exfoliated chlorite obtained in step a is dispersed in the solution. The mixture is subjected to ultrasonic treatment at 60°C for 24 hours. After the reaction is completed, solid-liquid separation is performed, the solid product is collected, and after washing, drying and grinding, the antifouling toughening modifier is obtained.

[0029] Example 3 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the method for preparing the antifouling and toughening modifier is different.

[0030] The preparation method of the antifouling and toughening modifier in this embodiment is as follows: a. Chlorite exfoliation: Chlorite mineral is ground into powder and dispersed in oxalic acid at a solid-liquid mass ratio of 1:15. The mixture is heated in a water bath at 70°C and stirred for 20 hours. Then, solid-liquid separation is performed, the solid product is collected and washed with deionized water until neutral, and dried to obtain exfoliated chlorite. b. Intercalation modification: Polymer-modified curcumin is dissolved in water, and the exfoliated chlorite obtained in step a is dispersed in the solution. The mixture is subjected to ultrasonic treatment at 50°C for 20 hours. After the reaction is completed, solid-liquid separation is performed, the solid product is collected, and after washing, drying and grinding, the antifouling toughening modifier is obtained.

[0031] Comparative Example 1 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the segmented mixing step (2) is cancelled and the material is directly weighed and mixed evenly according to the proportion.

[0032] Comparative Example 2 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the amount of antifouling and toughening modifier added is 2wt%.

[0033] Comparative Example 3 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the amount of antifouling and toughening modifier added is 11wt%.

[0034] Comparative Example 4 A method for preparing modified chlorite-toughened and antifouling PVC pipes is basically the same as that in Example 1, except that the antifouling and toughening modifier is replaced with a commercially available composition of elastomer MBS-66 + curcumin.

[0035] Comparative Example 5 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that citric acid is replaced with sulfuric acid in the preparation process of the antifouling and toughening modifier.

[0036] Comparative Example 6 A method for preparing modified chlorite toughened and antifouling PVC pipe is basically the same as that in Example 1, except that the polymer-modified curcumin is replaced with curcumin in the preparation of the antifouling and toughening modifier.

[0037] Test 1 PVC pipes were prepared from the coatings used in the examples and comparative examples. Impact performance was tested according to GB / T 1043.1-2008, tensile performance according to GB / T1040.2-2006, and flexural performance according to GB / T 9341-2008. The results are shown in Table 1. Table 1 Serial Number <![CDATA[Impact strength (KJ / m 2 )]]> Tensile strength (MPa) Bending strength (MPa) Example 1 9.6 45.8 112.3 Example 2 9.4 45.5 110.8 Example 3 9.2 44.8 108.9 Comparative Example 1 6.8 32.2 90.1 Comparative Example 2 5.5 28.0 75.5 Comparative Example 3 7.1 33.1 90.9 Comparative Example 4 7.3 23.5 74.2 Comparative Example 5 5.9 28.8 76.4 Comparative Example 6 1.5 18.9 56.3 As can be seen from the test results in Table 1, the modified PVC pipe successfully prepared by this invention achieves a high level of synergistic improvement in impact strength (toughness), tensile strength, and flexural strength (rigidity), breaking the contradiction of difficulty in achieving both "toughening" and "strengthening" in traditional modification technologies. Comparative Example 1 shows that the segmented mixing process is crucial for ensuring the uniform dispersion of the nanocomposite modifier in the PVC matrix; uneven dispersion will severely weaken its strengthening and toughening effects. Comparative Examples 2 and 3 show that insufficient modifier dosage results in insignificant strengthening and toughening effects, while excessive dosage may cause the modifier to agglomerate in the matrix, becoming defect points and reducing performance. Comparative Example 4 shows that traditional elastomer toughening severely reduces strength. Comparative Example 5 shows that using organic acids such as oxalic acid / citric acid for "exfoliation" treatment is necessary to gently open the chlorite layers, maintain their structural integrity to facilitate subsequent intercalation, and ultimately allow them to function within the matrix. Sulfuric acid may cause irreversible damage to the chlorite structure, thereby reducing its performance; as shown in Comparative Example 6, directly adding functional substances (curcumin) will damage the mechanical properties of the material. Combining Comparative Examples 5 and 6, the advantages of the unique composite structure of polymer-modified curcumin-intercalated chlorite in this patent are demonstrated.

[0038] Test 2 PVC pipes were prepared using the coatings from the examples and comparative examples. The water contact angle of these pipes was tested according to GB / T30693-2014, and the results are shown in Table 2. Table 2 Serial Number <![CDATA[Water contact angle / o > Example 1 62.5 Example 2 63.2 Example 3 63.8 Comparative Example 1 72.8 Comparative Example 2 95.6 Comparative Example 3 51.7 Comparative Example 4 135.6 Comparative Example 5 90.3 Comparative Example 6 126.9 As can be seen from the test results in Table 2, this invention successfully transformed the surface of PVC pipes from hydrophobic to hydrophilic by introducing a composite modifier. The water contact angle was significantly reduced from that of traditional PVC or poorly modified samples (>90°) to approximately 63°. This lays a crucial surface foundation for achieving physical antifouling. Comparative Example 1 shows that the segmented mixing process ensured the uniform dispersion of the composite modifier in the PVC matrix, ultimately forming a uniform and continuous hydrophilic phase on the product surface. Simplified processes resulted in uneven dispersion of the modifier, reducing the surface hydrophilic modification effect. Comparative Examples 2 and 3 show that both insufficient and excessive modifier dosage reduce the hydrophilic modification effect; insufficient dosage prevents the formation of an effective hydrophilic layer on the PVC surface, while excessive dosage causes the modifier to agglomerate, reducing the effectiveness of the hydrophilic modification. Comparative Examples 4 and 6 show that the water contact angle is extremely high (135.6°). o And 126.9 oThe presence of this material indicates that the surface is extremely hydrophobic. This is because both MBS elastomer and unmodified curcumin are hydrophobic substances. Comparative Example 5 shows that exfoliation treatment with organic acids (such as citric acid) is crucial for maintaining or enhancing the hydrophilicity of chlorite layers and for better combining them with PVA to modify surface properties. Sulfuric acid treatment may damage the surface chemical properties of chlorite, thereby reducing the hydrophilic modification effect.

[0039] Test 3 PVC pipes were prepared from the coatings used in the examples and comparative examples. Their antibacterial properties were tested according to GB 4789.2-2022, and the results are shown in Table 3. Serial Number Escherichia coli inhibition rate (%) Staphylococcus aureus inhibition rate (%) Example 1 99.5 99.4 Example 2 99.3 99.3 Example 3 99.1 99.0 Comparative Example 1 85.2 82.3 Comparative Example 2 77.6 74.2 Comparative Example 3 89.9 89.7 Comparative Example 4 65.2 64.8 Comparative Example 5 88.9 87.8 Comparative Example 6 68.9 68.3 As shown in Table 3, the PVC pipes prepared by this invention exhibit excellent antibacterial properties, with inhibition rates exceeding 99% against both *Escherichia coli* and *Staphylococcus aureus*. Comparative Examples 1 and 3 reveal that direct mixing, excessive use of modifiers, or treatment of chlorite with sulfuric acid, while showing some antibacterial effect, fail to completely inhibit bacteria, resulting in insufficient antifouling reliability under long-term use or harsh environments. Comparative Example 5 demonstrates that gentle exfoliation with organic acids (citric acid / oxalic acid) is necessary to maintain the integrity of the chlorite's lamellar structure, maximizing its curcumin loading capacity and regulating release characteristics; however, the strong corrosiveness of sulfuric acid may damage this carrier structure. Comparative Examples 2, 4, and 6 show that insufficient antibacterial agent dosage or exposure of curcumin significantly reduces antibacterial ability, failing to effectively prevent biofilm formation and posing a high risk of antifouling failure.

Claims

1. A modified chlorite-toughened and stain-resistant PVC pipe, characterized in that, By mass fraction, it contains the following raw materials: 70-80% PVC resin, 0.2-2% heat stabilizer, 1-5% lubricant, 5-10% impact modifier, 1-2% antioxidant, and 3-10% antifouling and toughening modifier; The antifouling and toughening modifier is obtained by polymer-modified curcumin intercalation into chlorite.

2. The PVC pipe as described in claim 1, characterized in that, The antifouling and toughening modifier is prepared by the following method: a. Chlorite exfoliation: Chlorite mineral is ground into powder and dispersed in organic acid at a solid-liquid mass ratio of 1:10 to 1:

20. The mixture is heated and stirred in a water bath at 60-80℃ for 6-24 hours. Then, solid-liquid separation is performed, the solid product is collected and washed with deionized water until neutral, and dried to obtain exfoliated chlorite. b. Intercalation modification: The polymer-modified curcumin is dissolved in water, and the exfoliated chlorite obtained in step a is dispersed in the solution. The mixture is subjected to ultrasonic treatment for 6-24 hours under heating conditions of 40-60℃. After the reaction is completed, solid-liquid separation is performed, the solid product is collected, and after washing, drying and grinding, the antifouling toughening modifier is obtained.

3. The PVC pipe as described in claim 2, characterized in that, In step b, the mass ratio of polymer-modified curcumin to exfoliated chlorite is 3-6:1, and the mass ratio of the total mass of the mixture obtained by adding polymer-modified curcumin and exfoliated chlorite to the mass of solvent water is 1:10-1:

20.

4. The PVC pipe as described in claim 2, characterized in that, The organic acid is one of oxalic acid and citric acid, with a concentration of 1 mol / L.

5. The PVC pipe as described in claim 2, characterized in that, The polymer-modified curcumin is prepared by the following steps: curcumin and polymer are heated at 90-100°C. o Dissolve in water at temperature C, mix and stir well, then place in an oven to dry at 40~60°C. o C, allowing the water to evaporate completely, yields polymer-modified curcumin.

6. The PVC pipe as described in claim 4, characterized in that, The polymer is polyvinyl alcohol.

7. A method for preparing modified chlorite-toughened and stain-resistant PVC pipe, characterized in that, Includes the following steps: (1) Ingredients: Weigh each component according to the following mass fractions: 70-80% PVC resin, 0.2-2% heat stabilizer, 1-5% lubricant, 5-10% impact modifier, 1-2% antioxidant, 3-10% antifouling and toughening modifier, and divide the antifouling and toughening modifier into two portions for later use, one of which accounts for 60%; (2) Segmented mixing: Mix all components except the antifouling and toughening modifier evenly, then add 60% of the total amount of the antifouling and toughening modifier to the mixture, mix evenly to obtain mixture 1, ultrasonically treat for 2-4 hours, then add the remaining antifouling and toughening modifier, and stir evenly. (3) Molding and processing: Add the auxiliary materials required for molding to the above-mentioned uniformly mixed materials, and obtain the modified chlorite toughened and antifouling PVC pipe by extrusion molding process.

8. The application of a modified chlorite-toughened antifouling PVC pipe as described in any one of claims 1-6 or a modified chlorite-toughened antifouling PVC pipe prepared by the preparation method described in claim 7 in water supply and drainage, building water supply or agricultural irrigation pipeline systems.

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