A corrosion-resistant PVC-U drainage pipe and its preparation method

Abstract

The present invention relates to the technical field of drain pipes and provides a corrosion-resistant PVC-U drain pipe and a method for preparing the same. The corrosion-resistant PVC-U drain pipe comprises the following components in parts by weight: 100 parts PVC, 3-6 parts acrylate copolymer, 1-2 parts polyacrylate rubber, 6-16 parts titanium-doped graphene, 10-13 parts filler, 2-4 parts titanium dioxide, 3.6-5 parts stabilizer, 0.15-0.3 parts lubricant, and 0.03-0.05 parts brightener; the raw materials for the titanium-doped graphene include graphene and a water-soluble titanium salt. This technical solution solves the problem of poor corrosion resistance of PVC-U drain pipes in related technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of drainage pipes, and in particular to a corrosion-resistant PVC-U drainage pipe and a preparation method thereof. Background Art

[0002] Due to their low cost and ease of processing, rigid polyvinyl chloride (PVC-U) drainage pipes are widely used in building drainage, municipal engineering, and other fields. However, long-term exposure to corrosive media (such as industrial wastewater and acid rain) can lead to corrosion and aging of traditional PVC-U drainage pipes, resulting in a decrease in mechanical properties and a shortened service life.

[0003] Currently, the primary method for improving the corrosion resistance of PVC-U drainage pipes involves adding corrosion-resistant fillers. For example, graphene and its derivatives (such as graphene oxide and graphene fluoride) are used as corrosion-resistant fillers due to their molecular resistance to molecular penetration. This improves the material's barrier properties and, consequently, its corrosion resistance. However, graphene's high electrical conductivity also contributes to its corrosion-activating properties, also known as corrosion-promoting activity. This corrosion-promoting effect compromises the material's actual corrosion resistance.

[0004] Therefore, developing a PVC-U drainage pipe that improves corrosion resistance by optimizing corrosive fillers is of great significance for meeting the long-term use requirements of PVC-U drainage pipes in harsh environments. Summary of the Invention

[0005] The present invention provides a corrosion-resistant PVC-U drainage pipe and a preparation method thereof, which solves the problem of poor corrosion resistance of the PVC-U drainage pipe in the related art.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention provides a corrosion-resistant PVC-U drainage pipe, comprising the following components in parts by weight:

[0008] 100 parts of PVC, 3-6 parts of acrylic copolymer, 1-2 parts of polyacrylate rubber, 6-16 parts of titanium-doped graphene, 10-13 parts of filler, 2-4 parts of titanium dioxide, 3.6-5 parts of stabilizer, 0.15-0.3 parts of lubricant, and 0.03-0.05 parts of brightener;

[0009] The raw materials of the titanium-doped graphene include graphene and water-soluble titanium salt.

[0010] The corrosion-resistant PVC-U drainage pipe of the present invention adopts PVC (polyvinyl chloride) as the base material, combined with acrylic ester copolymers, polyacrylate rubber, titanium-doped graphene, fillers, titanium dioxide, stabilizers, lubricants and whitening agents. With the cooperation of various components, the prepared PVC-U drainage pipe has good corrosion resistance, can meet the use requirements of drainage systems in different environments, and has a long service life and high reliability. Among them, PVC as the base material can provide basic structural support and basic corrosion resistance for the drainage pipe. Polyacrylate rubber can improve the toughness of the PVC-U drainage pipe, so that it can adapt to a certain degree of deformation without cracking, thereby improving its adaptability in different environments. Acrylic ester copolymers are HL series processing aids, which can improve the processability and fluidity of PVC materials. Titanium dioxide, as a white pigment, gives the corrosion-resistant PVC-U drainage pipe a good appearance.

[0011] In the corrosion-resistant PVC-U drain pipe of the present invention, by adding fillers, it can play a role in strengthening the skeleton in the PVC base material, improve the hardness and mechanical strength of the corrosion-resistant PVC-U drain pipe, enable the PVC-U drain pipe to withstand greater external forces and pressures, and is not prone to deformation and rupture. The filler can be an inorganic filler commonly used in this field, such as light calcium carbonate, talc, kaolin, and wollastonite, preferably light calcium carbonate. Light calcium carbonate is an inorganic filler commonly used in PVC-U drain pipes, has the advantages of low price and effectively reducing pipe processing costs. At the same time, light calcium carbonate can improve the hardness and dimensional stability of the PVC-U drain pipe.

[0012] In the corrosion-resistant PVC-U drain pipe of the present invention, the addition of a stabilizer can improve the thermal stability of PVC during processing, suppress the degradation reaction of PVC at high temperature, and the stabilizer can be a conventional stabilizer in the art, for example, it can be one or both of stearate and stearic acid, wherein stearate can be calcium stearate, zinc stearate, magnesium stearate, preferably calcium stearate, zinc stearate, more preferably calcium stearate. When the stabilizer includes calcium stearate and stearic acid, two stabilizers are used in combination, and there is an advantage of suppressing the thermal degradation of PVC for a long time. Wherein the weight ratio of calcium stearate and stearic acid is 9~17:1, for example, it can be 9:1, 10:1, 12:1, 14:1, 15:1, 17:1, preferably 9:1, 14:1, 17:1, more preferably 14:1.

[0013] In the corrosion-resistant PVC-U drainage pipe of the present invention, the addition of lubricant can reduce the friction between polymer molecules, making the material easier to flow during processing, thereby improving processing efficiency. The lubricant can be a commonly used lubricant in the field, such as polyethylene wax, oxidized polyethylene wax, preferably polyethylene wax.

[0014] In the corrosion-resistant PVC-U drain pipe of the present invention, the addition of a whitening agent can improve the glossiness of the corrosion-resistant PVC-U drain pipe, reduce the color unevenness problem between the PVC base material and other components during the processing, thereby improving the aesthetics of the corrosion-resistant PVC-U drain pipe. The whitening agent can be a fluorescent whitening agent commonly used in the art, for example, fluorescent whitening agent OB, fluorescent whitening agent OB-1, fluorescent whitening agent FP-127, fluorescent whitening agent CBS-127, preferably fluorescent whitening agent OB.

[0015] In the corrosion-resistant PVC-U drainage pipe of the present invention, the weight ratio of graphene to water-soluble titanium salt is 2 to 9:1, for example, it can be 2:1, 3:1, 4:1, 5:1, 7:1, 9:1, preferably 2:1, 3:1, 5:1, 9:1, and more preferably 3:1, 5:1.

[0016] In the corrosion-resistant PVC-U drain pipe of the present invention, a weight ratio of graphene to water-soluble titanium salt of 3 to 5:1 further improves the corrosion resistance of the PVC-U drain pipe. Compared to a weight ratio outside the range of 3 to 5:1, the PVC-U drain pipe prepared with a graphene to water-soluble titanium salt weight ratio of 3 to 5:1 shows a lesser decrease in tensile strength after immersion in a 15% hydrochloric acid solution, further improving the corrosion resistance of the PVC-U drain pipe.

[0017] In the corrosion-resistant PVC-U drainage pipe of the present invention, the water-soluble titanium salt may be any one or more water-soluble titanium salts in the art, such as titanium sulfate, titanyl sulfate, potassium titanium oxalate, preferably titanyl sulfate.

[0018] As a further technical solution, the method for preparing titanium-doped graphene comprises the following steps:

[0019] A1. Dispersing the graphene in dimethylformamide, adding a coupling agent solution, mixing evenly, concentrating, and drying to obtain a solid;

[0020] A2. Dissolve the water-soluble titanium salt in water, add the solid, mix well, add alkaline solution, stir, concentrate, and dry to obtain the titanium-doped graphene.

[0021] As a further technical solution, in step A2, the alkaline solution includes one or both of a sodium hydroxide aqueous solution and a sodium carbonate aqueous solution, preferably a sodium hydroxide aqueous solution, and the mass fraction of the alkaline solution is 6% to 15%, for example, 6%, 7%, 9%, 10%, 11%, 12%, 15%, preferably 10%.

[0022] In the corrosion-resistant PVC-U drainage pipe of the present invention, the coupling agent solution is a coupling agent solution commonly used in the field, for example, it can be γ-glycidyloxypropyltrimethoxysilane ethanol solution, γ-aminopropyltriethoxysilane ethanol solution, preferably γ-glycidyloxypropyltrimethoxysilane ethanol solution; the mass fraction of the coupling agent solution is 1% to 3%, for example, it can be 1%, 1.5%, 2%, 3%, preferably 2%.

[0023] As a further technical solution, in step A1, when the mixing is uniform, the stirring speed is 200-300 rpm, for example, 200 rpm, 220 rpm, 240 rpm, 250 rpm, 260 rpm, 300 rpm, preferably 200 rpm, 240 rpm, 300 rpm, more preferably 240 rpm, and the stirring time is 1-2 h, for example, 1 h, 1.1 h, 1.2 h, 1.3 h, 1.5 h, 1.6 h, 1.8 h, 2 h, preferably 1 h, 1.5 h, 2 h, more preferably 1.5 h;

[0024] In step A2, when the mixing is uniform, the stirring speed is 600-700 rpm, for example, it can be 600 rpm, 620 rpm, 650 rpm, 670 rpm, 680 rpm, 700 rpm, preferably 600 rpm, 650 rpm, 700 rpm, more preferably 650 rpm, and the stirring time is 20-30 min, for example, it can be 20 min, 22 min, 25 min, 26 min, 28 min, 30 min, preferably 20 min, 25 min, 30 min, more preferably 25 min.

[0025] As a further technical solution, the raw material of the titanium-doped graphene further includes bisphenol A novolac epoxy resin.

[0026] As a further technical solution, the weight ratio of the water-soluble titanium salt and the bisphenol A novolac epoxy resin to the graphene is 1:3-5;

[0027] The weight ratio of the water-soluble titanium salt to the bisphenol A novolac epoxy resin is 1.5:1.

[0028] In the corrosion-resistant PVC-U drain pipe of the present invention, after graphene is doped with water-soluble titanium salt, although the corrosion-promoting activity of graphene can be suppressed, it has little effect on weakening the van der Waals force between graphene layers and improving the dispersibility of graphene in the PVC substrate. When the raw material of titanium-doped graphene also includes bisphenol A novolac epoxy resin, the graphene is treated with water-soluble titanium salt and bisphenol A novolac epoxy resin together, which can improve the dispersion performance of graphene in the PVC substrate, thereby effectively filling the tiny pores between the PVC substrates and improving the thermal stability of the corrosion-resistant PVC-U drain pipe.

[0029] In the corrosion-resistant PVC-U drainage pipe of the present invention, by regulating the content ratio of the water-soluble titanium salt, the bisphenol A novolac epoxy resin and the graphene, when the weight ratio of the water-soluble titanium salt and the bisphenol A novolac epoxy resin to the graphene is 1:3-5, and the weight ratio of the water-soluble titanium salt and the bisphenol A novolac epoxy resin is 1.5:1, the thermal stability of the corrosion-resistant PVC-U drainage pipe can be effectively improved, and the longitudinal shrinkage rate of the corrosion-resistant PVC-U drainage pipe can be reduced to 1.0%-1.2%.

[0030] As a further technical solution, the method for preparing titanium-doped graphene comprises the following steps:

[0031] A1. Dispersing the graphene in dimethylformamide, adding a coupling agent solution, mixing evenly, concentrating, and drying to obtain a solid;

[0032] A2. Dissolving the water-soluble titanium salt in water, adding the solid, mixing evenly, adding an alkaline solution, stirring, concentrating, and drying to obtain the titanium-doped graphene pretreatment product;

[0033] A3. Dispersing the bisphenol A novolac epoxy resin in anhydrous ethanol, adding the titanium-doped graphene pretreatment material, mixing evenly, concentrating, and drying to obtain the titanium-doped graphene.

[0034] As a further technical solution, in step A3, when the mixing is uniform, ball milling is adopted, the ball milling speed is 200~300rpm, for example, it can be 200rpm, 220rpm, 240rpm, 250rpm, 260rpm, 300rpm, preferably 260rpm, and the ball milling time is 1~2h, for example, it can be 1h, 1.2h, 1.3h, 1.5h, 1.8h, 2h, preferably 1.5h.

[0035] The present invention also provides a method for preparing a corrosion-resistant PVC-U drainage pipe, which is used to prepare the corrosion-resistant PVC-U drainage pipe, comprising the following steps:

[0036] S1. Blending the components of the corrosion-resistant PVC-U drainage pipe, extruding and granulating to obtain pellets;

[0037] S2. Add the pellets into the hopper of an injection molding machine, install a drainage pipe injection mold, perform injection molding, and vacuum shaping to obtain the corrosion-resistant PVC-U drainage pipe.

[0038] The working principle and beneficial effects of the present invention are:

[0039] In the corrosion-resistant PVC-U drain pipe of the present invention, graphene is doped with a water-soluble titanium salt to obtain titanium-doped graphene. Adding this titanium-doped graphene to the corrosion-resistant PVC-U drain pipe effectively improves the corrosion resistance of the PVC-U drain pipe. In the prior art, graphene and its derivatives (such as graphene oxide and graphene fluoride) are commonly added directly. However, due to the high electrical conductivity of the graphene material itself, this material easily induces corrosion-promoting activity, resulting in a poor improvement in the corrosion resistance of the PVC-U drain pipe. To address this issue, the present invention uses a water-soluble titanium salt to dope graphene, which can reduce the impact of the graphene's corrosion-promoting activity on the corrosion resistance of the PVC-U drain pipe. Furthermore, the presence of titanium-doped graphene can, to a certain extent, limit the migration of small molecules in the PVC substrate, improving the stability of the internal structure of the PVC-U drain pipe, thereby improving the corrosion resistance of the PVC-U drain pipe. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the 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.

[0041] In the following examples and comparative examples:

[0042] The model of PVC is SG-5;

[0043] The model of acrylic copolymer is HL-701, purchased from Shandong Riko Chemical Co., Ltd.

[0044] The polyacrylate rubber model is ACM-P1, purchased from Shandong Riko Rubber & Plastic Technology Co., Ltd.

[0045] The model of bisphenol A novolac epoxy resin is NPES-901;

[0046] The particle size of graphene is 100nm;

[0047] The particle size of light calcium carbonate is 50nm;

[0048] The particle size of fluorinated graphene is 10 μm and the fluorine content is 60%.

[0049] Example 1

[0050] The preparation method of titanium-doped graphene comprises the following steps:

[0051] A1. Disperse 4 parts of graphene in 20 parts of dimethylformamide, add 0.5 parts of a 2% by mass solution of γ-glycidyloxypropyltrimethoxysilane in ethanol, stir at 200 rpm for 2 hours, concentrate, and dry to obtain a solid;

[0052] A2. Dissolve 2 parts of titanyl sulfate in 10 parts of water, add solid, stir at 600 rpm for 30 min, add 0.5 parts of 10% by mass sodium hydroxide aqueous solution, stir, concentrate, and dry to obtain titanium-doped graphene;

[0053] A method for preparing a corrosion-resistant PVC-U drainage pipe comprises the following steps:

[0054] S1. Blend 100 parts of PVC, 3 parts of acrylic copolymer, 1 part of polyacrylate rubber, 6 parts of titanium-doped graphene, 10 parts of light calcium carbonate, 2 parts of titanium dioxide, 3.4 parts of calcium stearate, 0.2 parts of stearic acid, 0.15 parts of polyethylene wax, and 0.03 parts of fluorescent brightener OB, and extrude and granulate to obtain pellets;

[0055] S2. Add the pellets into the hopper of the injection molding machine, install the drainage pipe injection mold, and perform injection molding and vacuum shaping to obtain a corrosion-resistant PVC-U drainage pipe.

[0056] Example 2

[0057] The preparation method of titanium-doped graphene comprises the following steps:

[0058] A1. Disperse 8 parts of graphene in 20 parts of dimethylformamide, add 0.5 parts of a 2% by mass solution of γ-glycidyloxypropyltrimethoxysilane in ethanol, stir at 240 rpm for 1.5 hours, concentrate, and dry to obtain a solid;

[0059] A2. Dissolve 4 parts of titanyl sulfate in 10 parts of water, add solid, stir at 650 rpm for 25 min, add 0.5 parts of 10% by mass sodium hydroxide aqueous solution, stir, concentrate, and dry to obtain titanium-doped graphene;

[0060] A method for preparing a corrosion-resistant PVC-U drainage pipe comprises the following steps:

[0061] S1. Blend 100 parts of PVC, 4 parts of acrylic copolymer, 1.5 parts of polyacrylate rubber, 12 parts of titanium-doped graphene, 12.5 parts of light calcium carbonate, 3 parts of titanium dioxide, 4.2 parts of calcium stearate, 0.3 parts of stearic acid, 0.2 parts of polyethylene wax, and 0.04 parts of fluorescent brightener OB, and extrude and granulate to obtain pellets;

[0062] S2. Add the pellets into the hopper of the injection molding machine, install the drainage pipe injection mold, and perform injection molding and vacuum shaping to obtain a corrosion-resistant PVC-U drainage pipe.

[0063] Example 3

[0064] A1. Disperse 14.4 parts of graphene in 20 parts of dimethylformamide, add 0.5 parts of a 2% by mass solution of γ-glycidyloxypropyltrimethoxysilane in ethanol, stir at 300 rpm for 1 hour, concentrate, and dry to obtain a solid;

[0065] A2. Dissolve 1.6 parts of titanyl sulfate in 10 parts of water, add solid, stir at 700 rpm for 20 min, add 0.5 parts of 10% by mass sodium hydroxide aqueous solution, stir, concentrate, and dry to obtain titanium-doped graphene;

[0066] A method for preparing a corrosion-resistant PVC-U drainage pipe comprises the following steps:

[0067] S1. Blend 100 parts of PVC, 6 parts of acrylic copolymer, 2 parts of polyacrylate rubber, 16 parts of titanium-doped graphene, 13 parts of light calcium carbonate, 4 parts of titanium dioxide, 4.5 parts of calcium stearate, 0.5 parts of stearic acid, 0.3 parts of polyethylene wax, and 0.05 parts of fluorescent brightener OB, and extrude and granulate to obtain pellets;

[0068] S2. Add the pellets into the hopper of the injection molding machine, install the drainage pipe injection mold, and perform injection molding and vacuum shaping to obtain a corrosion-resistant PVC-U drainage pipe.

[0069] Example 4

[0070] The only difference between this embodiment and embodiment 2 is that, in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 10.8 parts, and the amount of titanyl sulfate added is 1.2 parts.

[0071] Example 5

[0072] The only difference between this embodiment and embodiment 2 is that, in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 10 parts, and the amount of titanyl sulfate added is 2 parts.

[0073] Example 6

[0074] The only difference between this embodiment and embodiment 2 is that, in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 9 parts, and the amount of titanyl sulfate added is 3 parts.

[0075] Example 7

[0076] The only difference between this embodiment and embodiment 6 is that the preparation method of titanium-doped graphene in this embodiment is different, specifically:

[0077] A1. Disperse 8 parts of graphene in 20 parts of dimethylformamide, add 0.5 parts of a 2% by mass solution of γ-glycidyloxypropyltrimethoxysilane in ethanol, stir at 240 rpm for 1.5 hours, concentrate, and dry to obtain a solid;

[0078] A2. Dissolve 2.4 parts of titanyl sulfate in 10 parts of water, add solid, stir at 650 rpm for 25 min, add 0.5 parts of 10% by mass sodium hydroxide aqueous solution, stir, concentrate, and dry to obtain a titanium-doped graphene pretreatment product;

[0079] A3. Disperse 1.6 parts of bisphenol A novolac epoxy resin in 20 parts of anhydrous ethanol, add the titanium-doped graphene pretreatment material, and ball mill at 260 rpm for 1.5 h. Then, concentrate and dry to obtain titanium-doped graphene.

[0080] Example 8

[0081] The only difference between this embodiment and Example 7 is that in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 10.8 parts, the amount of titanyl sulfate added is 0.72 parts, and the amount of bisphenol A novolac epoxy resin added is 0.48 parts.

[0082] Example 9

[0083] The only difference between this embodiment and Example 7 is that in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 9 parts, the amount of titanyl sulfate added is 1.8 parts, and the amount of bisphenol A novolac epoxy resin added is 1.2 parts.

[0084] Example 10

[0085] The only difference between this embodiment and Example 7 is that in the preparation method of titanium-doped graphene in this embodiment, the amount of graphene added is 10 parts, the amount of titanyl sulfate added is 1.2 parts, and the amount of bisphenol A novolac epoxy resin added is 0.8 parts.

[0086] Comparative Example 1

[0087] The only difference between this comparative example and Example 2 is that in this comparative example, the titanium-doped graphene is replaced by an equal amount of graphene.

[0088] Comparative Example 2

[0089] The only difference between this comparative example and Example 2 is that in this comparative example, the titanium-doped graphene is replaced by an equal amount of fluorinated graphene.

[0090] Comparative Example 3

[0091] The only difference between this comparative example and Example 2 is that titanium-doped graphene is not added in this comparative example.

[0092] Experimental Example 1 Corrosion Resistance Test

[0093] The corrosion-resistant PVC-U drainage pipes with a thickness of 2 mm prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested for tensile strength before corrosion resistance according to the method in GB / T5836.1-2018 "Rigid Polyvinyl Chloride (PVC-U) Pipes for Building Drainage". The corrosion-resistant PVC-U drainage pipe samples prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were immersed in a 15% mass fraction hydrochloric acid solution for 48 hours, and then the tensile strength was tested after the corrosion test according to the above-mentioned tensile strength test method. The test results are shown in Table 1.

[0094] Table 1 Tensile strength test results

[0095]

[0096] Compared with Comparative Examples 1 to 3, the degree of decrease in tensile strength after corrosion of Examples 1 to 6 is less than that before corrosion, indicating that adding titanium-doped graphene obtained by doping graphene with water-soluble titanium salt to the corrosion-resistant PVC-U drainage pipe can effectively improve the corrosion resistance of the PVC-U drainage pipe.

[0097] Experimental Example 2 Thermal Stability Test

[0098] The corrosion-resistant PVC-U drainage pipes prepared in Examples 6 to 10 were subjected to a longitudinal shrinkage test according to the method in GB / T 5836.1-2018 "Uniform Polyvinyl Chloride (PVC-U) Pipes for Building Drainage". The test results are shown in Table 2.

[0099] Table 2 Longitudinal shrinkage test results

[0100]

[0101] Compared with Example 6, the longitudinal shrinkage rate of the corrosion-resistant PVC-U drainage pipes prepared in Examples 7 to 10 is reduced, indicating that when the titanium-doped graphene also includes bisphenol A novolac epoxy resin, the thermal stability of the corrosion-resistant PVC-U drainage pipes can be improved by jointly treating the graphene with bisphenol A novolac epoxy resin and water-soluble titanium salt.

[0102] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A corrosion-resistant PVC-U drainage pipe, characterized in that: The composition comprises the following components in parts by weight: 100 parts of PVC, 3-6 parts of acrylic copolymer, 1-2 parts of polyacrylate rubber, 6-16 parts of titanium-doped graphene, 10-13 parts of filler, 2-4 parts of titanium dioxide, 3.6-5 parts of stabilizer, 0.15-0.3 parts of lubricant, and 0.03-0.05 parts of brightener; The raw materials of the titanium-doped graphene include graphene and water-soluble titanium salt; The weight ratio of the graphene to the water-soluble titanium salt is 3 to 5:1; The raw material of the titanium-doped graphene also includes bisphenol A novolac epoxy resin.

2. The corrosion-resistant PVC-U drainage pipe according to claim 1, characterized in that: The water-soluble titanium salt includes titanyl sulfate.

3. The corrosion-resistant PVC-U drainage pipe according to claim 1, characterized in that: The preparation method of the titanium-doped graphene comprises the following steps: A1. Dispersing the graphene in dimethylformamide, adding a coupling agent solution, mixing evenly, concentrating, and drying to obtain a solid; A2. Dissolving the water-soluble titanium salt in water, adding the solid, mixing evenly, adding an alkaline solution, stirring, concentrating, and drying to obtain the titanium-doped graphene pretreatment product; A3. Dispersing the bisphenol A novolac epoxy resin in anhydrous ethanol, adding the titanium-doped graphene pretreatment material, mixing evenly, concentrating, and drying to obtain the titanium-doped graphene.

4. The corrosion-resistant PVC-U drainage pipe according to claim 3, characterized in that: In step A1, the mixing is carried out by stirring at a speed of 200-300 rpm for 1-2 hours. In step A2, the mixing is carried out uniformly by stirring at a speed of 600-700 rpm and a stirring time of 20-30 min.

5. The corrosion-resistant PVC-U drainage pipe according to claim 1, characterized in that: The weight ratio of the water-soluble titanium salt and the bisphenol A novolac epoxy resin to the graphene is 1:3-5; The weight ratio of the water-soluble titanium salt to the bisphenol A novolac epoxy resin is 1.5:

1.

6. The corrosion-resistant PVC-U drainage pipe according to claim 1, characterized in that: The filler includes light calcium carbonate.

7. The corrosion-resistant PVC-U drainage pipe according to claim 1, characterized in that: The stabilizer includes one or more of calcium stearate, zinc stearate, and stearic acid; The whitening agent includes fluorescent whitening agent OB; The lubricant includes polyethylene wax.

8. A method for preparing a corrosion-resistant PVC-U drainage pipe, for preparing a corrosion-resistant PVC-U drainage pipe according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Blending the components of the corrosion-resistant PVC-U drainage pipe, extruding and granulating to obtain pellets; S2. Add the pellets into the hopper of an injection molding machine, install a drainage pipe injection mold, perform injection molding, and vacuum shaping to obtain the corrosion-resistant PVC-U drainage pipe.

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