PVC (polyvinyl chloride) drainage pipe material and preparation method thereof

Abstract

The invention discloses a PVC drainage pipe and a preparation method thereof, and belongs to the technical field of plastic pipes. The PVC drainage pipe material comprises the following raw materials: 90-100 parts of PVC resin, 10-20 parts of filler, 2-5 parts of a heat stabilizer, 1-4 parts of chlorinated polyethylene, 1-3 parts of a coupling agent, 2-4 parts of an anti-aging agent, 1-1.5 parts of a lubricant and 0.01-0.1 part of an initiator. A cross-linked hybrid network structure is formed among the anti-aging agent, the filler and the PVC resin, so that the filler and the anti-aging agent can be highly dispersed and stably exist in the PVC drainage pipe material, are not easy to migrate and fall off, and continuously and stably play roles in enhancing the mechanical property, oxidation resistance, light stability and the like of the PVC drainage pipe material; different from commercially available micromolecular antioxidants, the anti-aging agent disclosed by the invention not only can be better compatible with PVC resin, but also is more difficult to migrate and separate, and can give full play to the anti-oxidation effect and the light stabilization effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic pipes, and specifically relates to a PVC drainage pipe and a preparation method thereof. Background Art

[0002] As an indispensable part of modern buildings, the drainage system directly affects the living quality of residents. In recent years, with the acceleration of the urbanization process, the demand for efficient drainage systems has been increasing. PVC (polyvinyl chloride) materials, with their excellent chemical stability, light weight, durability and low cost advantages, have been widely used globally, especially playing a key role in the drainage networks of civil and commercial buildings. The development of PVC pipes in China is relatively fast. Among plastic pipes, the consumption of PVC pipes has always been far ahead, and it is widely used in water supply and drainage pipes.

[0003] However, there is no chemical interaction between the anti-aging agent and the matrix resin in the existing PVC drainage pipes. Therefore, the anti-aging agent will inevitably migrate or escape from the PVC drainage pipes during use, and its anti-aging effect cannot be exerted permanently, resulting in the aging of the PVC drainage pipes and the abnormal operation of the pipes. Therefore, it is urgent to prepare a PVC drainage pipe with excellent anti-aging performance to extend the service life and ensure the stable operation of the pipes. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a PVC drainage pipe and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A PVC drainage pipe comprises the following raw materials in parts by weight: 90 - 100 parts of PVC resin, 10 - 20 parts of filler, 2 - 5 parts of heat stabilizer, 1 - 4 parts of chlorinated polyethylene, 1 - 3 parts of coupling agent, 2 - 4 parts of anti-aging agent, 1 - 1.5 parts of lubricant, and 0.01 - 0.1 part of initiator.

[0007] Further, the filler is one or more of calcium carbonate, talcum powder, fumed silica, magnesium carbonate, wollastonite, mica, and titanium dioxide.

[0008] Further, the heat stabilizer is a calcium-zinc composite stabilizer.

[0009] Further, the coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane.

[0010] The coupling agents are all coupling agents containing carbon-carbon double bonds. When added to PVC drainage pipes, they can effectively disperse the fillers, and thus the fillers of the present invention can significantly enhance the wear resistance, heat resistance, and mechanical properties of PVC drainage pipes. In addition, the coupling agents also introduce carbon-carbon double bonds on the surface of the fillers. Then, under the action of an initiator during the extrusion process, the carbon-carbon double bonds on the surface of the fillers react chemically with the carbon-carbon double bonds in the anti-aging agent and the unreacted carbon-carbon double bonds at the ends of the PVC resin. As a result, a crosslinked hybrid network structure is formed among the fillers, anti-aging agent, and PVC resin of the present invention. This structure enables the fillers and anti-aging agent to be highly dispersed and stably present in the PVC drainage pipes, not easily migrating or escaping, and can continuously and stably play the role of enhancing the wear resistance, heat resistance, mechanical properties, antioxidant properties, and light stability of PVC drainage pipes, thereby extending the service life of PVC drainage pipes and ensuring the normal operation of the pipes.

[0011] Furthermore, the anti-aging agent is prepared through the following steps:

[0012] S1. Add 3,5-di-tert-butyl-4-hydroxycinnamic acid, EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride), NHS (N-hydroxysuccinimide), and chloroform into a dry three-necked flask. After stirring and dissolving, slowly add diethylenetriamine, then raise the temperature to 60 °C, keep the temperature for reaction for 6 h. After the reaction is completed, cool to room temperature, perform reduced-pressure distillation, and purify by column chromatography (select a mixed solvent of cyclohexane and ethyl acetate as the eluent, and the volume ratio of cyclohexane to ethyl acetate is 1:1), and perform reduced-pressure distillation to obtain Intermediate 1; the dosage ratio of 3,5-di-tert-butyl-4-hydroxycinnamic acid, diethylenetriamine, EDC, NHS, and chloroform is 28 g:12.9 mL:0.58 g:0.35 g:200 mL;

[0013] Under the action of EDC and NHS, control the molar ratio of 3,5-di-tert-butyl-4-hydroxycinnamic acid to diethylenetriamine to be 1:1.1 - 1.2, then the -COOH of 3,5-di-tert-butyl-4-hydroxycinnamic acid reacts with the -NH2 of diethylenetriamine to undergo an amidation reaction, and the reaction equation is as follows:

[0014]

[0015] S2. Under nitrogen protection, add 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid, triethylamine and toluene into a three-necked flask. After stirring and dissolving, slowly add 10-bromo-1-decene. After the addition, heat up to 75 °C and stir for 3 h. After the reaction is completed, cool to room temperature, carry out vacuum distillation, and purify by column chromatography (the eluent is a mixed solvent of benzene and ethyl acetate, and the volume ratio of benzene to ethyl acetate is 8:2). Carry out vacuum distillation to obtain intermediate 2; the dosage ratio of 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid, 10-bromo-1-decene, triethylamine and toluene is 21.5 g:20 mL:17 mL:200 mL;

[0016] Triethylamine is used as an acid-binding agent to control the molar ratio of 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid to 10-bromo-1-decene to be 1.05 - 1.1:1. The -NH- of 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid undergoes a substitution reaction with the -Br of 10-bromo-1-decene. The reaction process is as follows:

[0017]

[0018] S3. Add intermediate 1, EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride), NHS (N-hydroxysuccinimide) and dimethyl sulfoxide into a dry three-necked flask. After stirring and dissolving, slowly add intermediate 2, then heat up to 70 °C and keep the temperature for 8 h. After the reaction is completed, cool to room temperature, carry out vacuum distillation, and purify by column chromatography (the eluent is a mixed solvent of benzene and methanol, and the volume ratio of benzene to methanol is 19:1). Carry out vacuum distillation to obtain intermediate 3; the dosage ratio of intermediate 1, intermediate 2, EDC, NHS and dimethyl sulfoxide is 21 g:17 g:0.029 g:0.017 g:240 mL;

[0019] Under the action of EDC and NHS, control the molar ratio of intermediate 1 to intermediate 2 to be 1.1 - 1.2:1, then the -NH2 of intermediate 1 and the -COOH of intermediate 2 undergo an amidation reaction. The reaction equation is as follows:

[0020]

[0021] S4. Under nitrogen protection, add polyvinyl chloride, triethylamine, intermediate 4 and DMF (N,N-dimethylformamide) into a sufficiently dry three-necked flask. After stirring and dissolving, heat up to 60 °C and keep the temperature for 9.5 h. After the reaction is completed, first cool to room temperature, then carry out vacuum distillation, and finally dry in vacuum at 50 °C to obtain the anti-aging agent; the dosage ratio of polyvinyl chloride, intermediate 4, triethylamine and DMF is 46.9 g:4.5 g:1.1 mL:260 mL.

[0022] Triethylamine is used as an acid-binding agent, and the -NH- of intermediate 3 undergoes a substitution reaction with the -Cl of polyvinyl chloride. The reaction process is as follows:

[0023]

[0024] The anti-aging agent prepared by the present invention contains a hindered phenol structure and a hindered amine structure. The hindered phenol structure can capture the free radicals generated during the oxidation process of high molecular polymers, interrupt the free radical chain reaction, thereby preventing further oxidative degradation and improving the antioxidant ability of PVC drainage pipes. The hindered amine structure can effectively capture the active free radicals generated under the action of ultraviolet light by high molecular polymers, thereby exerting a light stabilizing effect and achieving the purpose of preventing oxidation. The combination of the hindered phenol structure and the hindered phenol structure has excellent synergistic effects.

[0025] The anti-aging agent of the present invention contains lipophilic ester groups, benzene rings and long carbon chains, so the anti-aging agent has good compatibility with the remaining raw materials, and the anti-aging agent can be evenly dispersed in PVC drainage pipes. At the same time, the anti-aging agent contains carbon-carbon double bonds, so the anti-aging agent can form an interpenetrating hybrid network structure with fillers and PVC resin, and the anti-aging agent can stably exist in this network structure, and thus stably exist in PVC drainage pipes, and play a stable and excellent antioxidant effect and light stabilizing effect for a long time; in addition, the anti-aging agent of the present invention also contains polyvinyl chloride macromolecular chains, which makes the anti-aging agent of the present invention different from commercially available small molecule antioxidants. It can not only be better compatible with PVC resin, but also be less likely to migrate and escape, and can be more stable in PVC drainage pipes, fully exerting the antioxidant effect and light stabilizing effect, prolonging the service life of PVC drainage pipes and ensuring the normal operation of the pipeline.

[0026] Further, the lubricant is one or more of paraffin, calcium stearate, oxidized polyethylene wax, ethylene bisstearamide.

[0027] Further, the initiator is one or more of bis(2-ethylhexyl) peroxydicarbonate, azobisisobutyronitrile, benzoyl peroxide, diisopropylbenzene peroxide.

[0028] A preparation method of a PVC drainage pipe includes the following steps:

[0029] Weigh each raw material by weight and add it to a high-speed mixer for mixing. After hot mixing to 120°C - 140°C, it is then discharged into a low-speed cold mixer for cooling. After cold mixing to 45°C - 55°C, the powder is discharged into the hopper of an extruder through a tube chain drag, and is extruded and molded by the extruder and injection molded by an injection molding machine. After cooling, curing and shaping, a PVC drainage pipe is obtained.

[0030] The beneficial effects of the present invention:

[0031] (1) The antioxidant of the present invention forms a cross-linked hybrid network structure with the filler and the PVC resin, so that the filler and the antioxidant can be highly dispersed and stably present in the PVC drainage pipe, and are not easy to migrate and fall out. They can continuously and stably play the role of enhancing the wear resistance and heat resistance, mechanical properties, oxidation resistance and light stability of the PVC drainage pipe, thereby extending the service life of the PVC drainage pipe and ensuring the normal operation of the pipeline.

[0032] (2) The antioxidant of the present invention contains a polyvinyl chloride macromolecular chain, which makes the antioxidant of the present invention different from the small molecule antioxidants on the market. It is not only more compatible with the PVC resin, but also less likely to migrate and escape. It can be further stabilized in the PVC drainage pipe and give full play to the antioxidant effect and light stabilization effect. DETAILED DESCRIPTION

[0033] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0034] All the raw materials used in the examples and comparative examples are from:

[0035] 3,5-di-tert-butyl-4-hydroxycinnamic acid: CAS No. 22014-01-3, Shanghai Mairui Biochemical Technology Co., Ltd., purity 98%;

[0036] Diethylenetriamine: CAS No. 111-40-0, Aladdin Biochemical Technology Co., Ltd., purity ≥ 98.5%;

[0037] 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid: CAS No. 34635-77-3, Beijing Bailingwei Technology Co., Ltd.;

[0038] 10-Bromo-1-decene: CAS No. 62871-09-4, Aladdin Biochemical Technology Co., Ltd., purity ≥95%;

[0039] Polyvinyl chloride: CAS No. 9002-86-2, Aladdin Biochemical Technology Co., Ltd., K value 59-55;

[0040] EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride): CAS No. 25952-53-8, Jier Biochemical (Shanghai) Co., Ltd., purity 98%;

[0041] NHS (N-Hydroxysuccinimide): CAS No. 6066-82-6, Aladdin Biochemical Technology Co., Ltd., purity 98%;

[0042] Triethylamine: CAS No. 121-44-8, Jiangsu Runfeng Synthetic Technology Co., Ltd., purity 99%;

[0043] Dimethyl sulfoxide: CAS No. 67-68-5, Shandong Naibaichuan Chemical Sales Co., Ltd., purity 99.99%;

[0044] DMF (N,N-Dimethylformamide): CAS No. 68-12-2, Shanghai Merck Chemical Technology Co., Ltd., purity ≥99.9%;

[0045] Antioxidant 1076: CAS No. 2082-79-3, Aladdin Biochemical Technology Co., Ltd.;

[0046] Light stabilizer 944: CAS No. 71878-19-8, Aladdin Biochemical Technology Co., Ltd.

[0047] Example 1, preparation of anti-aging agent, the specific steps are as follows:

[0048] S1. Add 28 g of 3,5-di-tert-butyl-4-hydroxycinnamic acid, 0.58 g of EDC, 0.35 g of NHS and 200 mL of chloroform into a 500 mL dry three-necked flask. After stirring and dissolving, slowly add 12.9 mL of diethylenetriamine, then raise the temperature to 60 °C and keep the reaction for 6 h. After the reaction is completed, cool to room temperature, carry out vacuum distillation, and purify by column chromatography (the eluent is a mixed solvent of cyclohexane and ethyl acetate, and the volume ratio of cyclohexane to ethyl acetate is 1:1), and carry out vacuum distillation to obtain Intermediate 1;

[0049] S2. Under nitrogen protection, add 21.5 g of 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid, 17 mL of triethylamine and 200 mL of toluene into a 500 mL three-necked flask. After stirring and dissolving, slowly add 20 mL of 10-bromo-1-decene. After adding, raise the temperature to 75 °C and stir the reaction for 3 h. After the reaction is completed, cool to room temperature, carry out vacuum distillation, and purify by column chromatography (the eluent is a mixed solvent of benzene and ethyl acetate, and the volume ratio of benzene to ethyl acetate is 8:2), and carry out vacuum distillation to obtain Intermediate 2;

[0050] S3. Add 21 g of Intermediate 1, 0.029 g of EDC, 0.017 g of NHS, and 240 mL of dimethyl sulfoxide into a 500 mL dry three-necked flask. After stirring and dissolving, slowly add 17 g of Intermediate 2, then raise the temperature to 70 °C, keep the temperature for reaction for 8 h. After the reaction is completed, cool to room temperature, perform vacuum distillation, and purify by column chromatography (select a mixed solvent of benzene and methanol as the eluent, and the volume ratio of benzene to methanol is 19:1), then perform vacuum distillation to obtain Intermediate 3;

[0051] S4. Under nitrogen protection, add 46.9 g of polyvinyl chloride, 1.1 mL of triethylamine, 4.5 g of Intermediate 4, and 260 mL of DMF into a 500 mL thoroughly dried three-necked flask. After stirring and dissolving, raise the temperature to 60 °C, keep the temperature for reaction for 9.5 h. After the reaction is completed, first cool to room temperature, then perform vacuum distillation, and finally dry under vacuum at 50 °C to obtain the anti-aging agent.

[0052] Example 2. To prepare the anti-aging agent, the specific steps are as follows:

[0053] Keep the other steps unchanged, only remove step S4 of Example 1 to prepare the anti-aging agent.

[0054] Example 3. To prepare PVC drainage pipes, the specific steps are as follows:

[0055] Weigh 90 parts of PVC resin, 3 parts of calcium carbonate, 3 parts of mica, 4 parts of titanium dioxide, 2 parts of calcium-zinc composite stabilizer, 1 part of chlorinated polyethylene, 1 part of vinyltrimethoxysilane, 2 parts of the anti-aging agent prepared in Example 1, 1 part of paraffin wax, and 0.01 part of diisopropylbenzene peroxide by weight and add them to a high-speed mixer for mixing. After hot mixing to 120 °C, then discharge them into a low-speed cold mixer for cooling. After cold mixing to 45 °C, drag the powder to the hopper of the extruder through a tube chain, and extrude and injection mold through the extruder and injection molding machine. After cooling, curing, and shaping, PVC drainage pipes are obtained.

[0056] Example 4. To prepare PVC drainage pipes, the specific steps are as follows:

[0057] Weigh 95 parts by weight of PVC resin, 3 parts of talcum powder, 3 parts of fumed silica, 3 parts of magnesium carbonate, 3 parts of wollastonite, 4 parts of titanium dioxide, 4 parts of calcium-zinc composite stabilizer, 3 parts of chlorinated polyethylene, 1 part of vinyltrimethoxysilane, 1 part of 3-(methacryloyloxy)propyltrimethoxysilane, 3 parts of the anti-aging agent prepared in Example 1, 0.6 parts of calcium stearate, 0.6 parts of oxidized polyethylene wax, 0.05 parts of dibenzoyl peroxide, and dicumyl peroxide, and add them to a high-speed mixer for mixing. After hot mixing to 140 °C, it is then discharged into a low-speed cold mixer for cooling. After cold mixing to 55 °C, the powder is discharged into the hopper of the extruder by tube chain dragging, and is extruded and molded by the extruder and injection molded by the injection molding machine. After cooling, curing, and shaping, PVC drainage pipes are obtained.

[0058] Example 5, Preparation of PVC Drainage Pipes, the specific steps are as follows:

[0059] Weigh 100 parts by weight of PVC resin, 5 parts of calcium carbonate, 5 parts of magnesium carbonate, 5 parts of mica, 5 parts of titanium dioxide, 5 parts of calcium-zinc composite stabilizer, 4 parts of chlorinated polyethylene, 3 parts of vinyltriethoxysilane, 4 parts of the anti-aging agent prepared in Example 1, 0.5 parts of paraffin wax, 0.5 parts of calcium stearate, 0.5 parts of ethylene bisstearamide, 0.1 parts of bis(2-ethylhexyl) peroxydicarbonate, and add them to a high-speed mixer for mixing. After hot mixing to 130 °C, it is then discharged into a low-speed cold mixer for cooling. After cold mixing to 50 °C, the powder is discharged into the hopper of the extruder by tube chain dragging, and is extruded and molded by the extruder and injection molded by the injection molding machine. After cooling, curing, and shaping, PVC drainage pipes are obtained.

[0060] Comparative Example 1, Preparation of PVC Drainage Pipes, the specific steps are as follows:

[0061] The remaining steps remain unchanged, and only the anti-aging agent in Example 3 is replaced with the anti-aging agent prepared in Example 2, thus preparing PVC drainage pipes.

[0062] Comparative Example 2, Preparation of PVC Drainage Pipes, the specific steps are as follows:

[0063] The remaining steps remain unchanged, and only the anti-aging agent in Example 3 is replaced with 1 part of antioxidant 1076 and 1 part of light stabilizer 944, thus preparing PVC drainage pipes.

[0064] Performance Testing

[0065] The following performance tests are carried out on Examples 3-5 and Comparative Examples 1-2, and the test results of all items are shown in Table 1:

[0066] Tensile Strength Test: Refer to GB / T1040.2-2022 Plastics - Determination of tensile properties - Part 2;

[0067] Aging Test:

[0068] (1) It is carried out with reference to GB / T 16422.3-2014 "Plastics - Methods of exposure to laboratory light sources - Part 3: Fluorescent UV lamps". The wavelength of the UV lamp is 313 nm. The sample is subjected to light treatment at 70 °C, and the total test duration is 150 h. Tensile strength test is carried out.

[0069] (2) It is dry-heat aged at 105 °C for 150 h, and the tensile strength test is carried out with reference to the second part of GB / T 1040.2-2022 "Determination of tensile properties of plastics".

[0070] Table 1

[0071]

[0072] In the description of the specification, the description of reference terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0073] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A PVC drainage pipe, characterized in that: The invention comprises the following raw materials in parts by weight: 90-100 parts of PVC resin, 10-20 parts of filler, 2-5 parts of heat stabilizer, 1-4 parts of chlorinated polyethylene, 1-3 parts of coupling agent, 2-4 parts of anti-aging agent, 1-1.5 parts of lubricant and 0.01-0.1 parts of initiator; Wherein, the anti-aging agent is prepared by the following steps: S1. Add 3,5-di-tert-butyl-4-hydroxycinnamic acid, EDC, NHS and chloroform into a flask, add diethylenetriamine after stirring, heat to 60°C and react for 6 hours. After the reaction is completed, cool to room temperature, distill under reduced pressure, purify by column chromatography, and distill under reduced pressure to obtain intermediate 1; the amount ratio of 3,5-di-tert-butyl-4-hydroxycinnamic acid, diethylenetriamine, EDC, NHS and chloroform is 28g:12.9mL:0.58g:0.35g:200mL; S2. Under nitrogen protection, 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid, triethylamine and toluene were added into a flask, 10-bromo-1-decene was added after stirring, the temperature was raised to 75°C and the reaction was carried out for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, distilled under reduced pressure, purified by column chromatography, and distilled under reduced pressure to obtain intermediate 2; the dosage ratio of 2-(2,2,6,6-tetramethylpiperidin-4-yl)acetic acid, 10-bromo-1-decene, triethylamine and toluene was 21.5 g:20 mL:17 mL:200 mL; S3, intermediate 1, EDC, NHS and dimethyl sulfoxide were added to a flask, and intermediate 2 was added after stirring, and the temperature was raised to 70°C for reaction for 8 hours, and the mixture was cooled to room temperature, and the mixture was distilled under reduced pressure, purified by column chromatography, and distilled under reduced pressure to obtain intermediate 3; the amount ratio of intermediate 1, intermediate 2, EDC, NHS and dimethyl sulfoxide was 21g:17g:0.029g:0.017g:240mL; S4. Add polyvinyl chloride, triethylamine, intermediate 4 and DMF into a flask under nitrogen protection, heat to 60°C after stirring, and react for 9.5 hours. After the reaction, cool to room temperature, distill under reduced pressure, and dry to obtain an anti-aging agent; the dosage ratio of polyvinyl chloride, intermediate 4, triethylamine and DMF is 46.9g:4.5g:1.1mL:260mL.

2. A PVC drainage pipe according to claim 1, characterized in that: The coupling agent is one or more of vinyl trimethoxy silane, vinyl triethoxy silane and 3-(methacryloyloxy)propyl trimethoxy silane.

3. A PVC drainage pipe according to claim 1, characterized in that: The filler is one or more of calcium carbonate, talc, fumed silica, magnesium carbonate, wollastonite, mica and titanium dioxide.

4. A PVC drainage pipe according to claim 1, characterized in that: The heat stabilizer is a calcium-zinc composite stabilizer.

5. A PVC drainage pipe according to claim 1, characterized in that: The lubricant is one or more of paraffin wax, calcium stearate, oxidized polyethylene wax, and ethylene bisstearamide.

6. A PVC drainage pipe according to claim 1, characterized in that: The initiator is one or more of di(2-ethylhexyl) peroxydicarbonate, azobisisobutyronitrile, dibenzoyl peroxide, and diisopropylbenzene peroxide.

7. The method for preparing a PVC drainage pipe according to claim 1, characterized in that: The following steps are involved: Weigh each raw material by weight and add it to a high-speed mixer for mixing. After hot mixing at 120°C-140°C, discharge it into a low-speed cold mixer for cooling. After cold mixing at 45°C-55°C, discharge the powder into the hopper of the extruder by dragging a pipe chain, extrude it into shape by the extruder and inject it into shape by the injection molding machine, and obtain the PVC drainage pipe after cooling, curing and shaping.

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