Weather-proof anti-scale PE (polyethylene) drainage pipe and preparation method thereof

Abstract

The invention discloses a weather-proof anti-scale PE drainage pipe and a preparation method thereof, and relates to the field of pipes. The weather-proof and anti-scale PE drainage pipe comprises an anti-scale PE inner layer and a weather-proof PE outer layer, and the anti-scale PE inner layer is prepared from the following raw materials in parts by weight: 100 parts of first HDPE resin, 4.5-5.5 parts of modified zinc oxide whiskers, 1-2 parts of polyolefin wax and 0.005-0.01 part of a first initiator; the modified zinc oxide whiskers are obtained by at least modifying zinc oxide whiskers with a vinyl / allyl silane coupling agent. The PE drainage pipe with excellent anti-scaling performance can be obtained through synergistic cooperation of the modified zinc oxide whiskers and the polyethylene wax.

Description

Technical Field

[0001] The present application relates to the field of pipe materials, and particularly to a weather-resistant and scale-resistant PE drainage pipe and a preparation method thereof. Background Art

[0002] Due to its good chemical stability, corrosion resistance, and convenient construction, PE drainage pipes are widely used in construction, municipal engineering, etc. However, there are still some problems to be solved urgently in the actual use of existing PE drainage pipes.

[0003] For example: There are often various microorganisms and impurities in drainage pipes. The growth of microorganisms and the attachment of impurities are likely to form dirt, which will not only affect the drainage efficiency of drainage pipes, but also may cause pipe blockage and increase maintenance costs. Although zinc oxide whiskers have antibacterial effects and can inhibit the growth of microorganisms, theoretically, they can improve the scale resistance of PE drainage pipes. However, there is a problem of poor interfacial compatibility between zinc oxide whiskers and the resin matrix in PE resin, which will cause uneven dispersion of zinc oxide or poor interfacial bonding strength, greatly reducing the effect of improving the scale resistance by antibacterial. Summary of the Invention

[0004] In order to improve the scale resistance of PE drainage pipes, the present application provides a weather-resistant and scale-resistant PE drainage pipe and a preparation method thereof.

[0005] In the first aspect, a weather-resistant and scale-resistant PE drainage pipe provided by the present application adopts the following technical solution: A weather-resistant and scale-resistant PE drainage pipe includes a scale-resistant PE inner layer and a weather-resistant PE outer layer. The preparation raw materials of the scale-resistant PE inner layer include 100 parts by weight of a first HDPE resin, 4.5 - 5.5 parts by weight of modified zinc oxide whiskers, 1 - 2 parts by weight of polyolefin wax, and 0.005 - 0.01 parts by weight of a first initiator. The modified zinc oxide whiskers are obtained by modifying zinc oxide whiskers with at least a vinyl / allyl silane coupling agent; the preparation raw materials of the weather-resistant PE outer layer include 100 parts by weight of a second HDPE resin, 0.002 - 0.004 parts by weight of a PE-carbon black masterbatch, 6.5 - 7.5 parts by weight of acrylate-capped silicone oil, and 0.01 - 0.015 parts by weight of a second initiator.

[0006] Zinc oxide whiskers have antibacterial effects and can inhibit the growth of microorganisms, and can improve the scale resistance of the scale-resistant PE inner layer. However, zinc oxide whiskers are prone to poor interfacial compatibility between the resin matrixes in PE resin, which is likely to cause problems such as uneven dispersion of zinc oxide or poor interfacial bonding strength.

[0007] To this end, in the anti-scaling PE inner layer of the PE drainage pipe of the present application, modified zinc oxide whiskers are used instead of zinc oxide whiskers. The modified zinc oxide whiskers are obtained by modifying zinc oxide whiskers with at least vinyl / allyl silane coupling agents. Among them, the silanol groups generated after hydrolysis of the vinyl / allyl silane coupling agent react with the hydroxyl groups on the surface of the zinc oxide whiskers to graft the vinyl / allyl silane coupling agent onto the surface of the zinc oxide whiskers. Then, the free radicals decomposed by the first initiator in a high-temperature environment initiate the cross-linking reaction between the carbon-carbon double bonds in the modified zinc oxide whiskers and the first HDPE resin to form a cross-linked network, effectively improving the interfacial bonding strength between the vinyl / allyl silane coupling agent-modified zinc oxide whiskers and the first HDPE resin, which is beneficial to obtaining a PE anti-scaling inner layer with long-term antibacterial effects. Polyolefin wax can reduce the melt viscosity of the first HDPE resin, which is beneficial to promoting the uniform dispersion of the modified zinc oxide whiskers in the first HDPE resin melt, improving the melt fluidity after incorporating the modified zinc oxide whiskers, and facilitating the preparation of an anti-scaling PE inner layer with a smooth inner wall and small roughness to weaken the adhesion of scaling substances on the anti-scaling PE inner layer and reduce the adhesion of scaling substances. That is, with the combined action of the antibacterial modified zinc oxide whiskers and the anti-scaling PE inner layer with a smooth inner wall in the present application, a PE drainage pipe with good anti-scaling performance can be obtained.

[0008] In addition, in the weather-resistant PE outer layer of the present application, a PE-carbon black masterbatch capable of effectively absorbing ultraviolet rays is added to prevent the problem of aging of the PE drainage pipe due to ultraviolet irradiation during outdoor use; acrylate-capped silicone oil and a second initiator are added, and under the initiation of the second initiator, the acrylate-capped silicone oil reacts with the second HDPE resin to cross-link, which can further improve the heat-aging resistance of the weather-resistant PE outer layer and is beneficial to obtaining a PE drainage pipe with good weather resistance.

[0009] In some specific embodiments, the diameter of the modified zinc oxide whiskers is 30-40 nm, the length is 200-300 nm, and the aspect ratio is 5-10.

[0010] In some specific embodiments, the structural formula of the acrylate-capped silicone oil is as follows: CH 2 =CR 1 COO(CH 2 ) 3 SiR 2 R 3 O(SiR 2 R 3 O) n SiR 2 R 3 (CH 2 ) 3 OOCCR 1 =CH 2 ; Among them, R1 is H or an alkyl group, R2 and R3 are alkyl groups or phenyl groups, and the value range of n is 40 - 50.

[0011] In some specific embodiments, the acrylate - terminated silicone oil includes acrylate - terminated silicone oil A and acrylate - terminated silicone oil B, and the weight ratio of acrylate - terminated silicone oil A to acrylate - terminated silicone oil B is (3 - 4):1; among them, in acrylate - terminated silicone oil A, R1 is H, and R2 and R3 are methyl groups; in acrylate - terminated silicone oil B, R1 is a methyl group, R2 is a methyl group, and R3 is a phenyl group.

[0012] This application preferably uses a composition of acrylate - terminated silicone oil A and acrylate - terminated silicone oil B as the acrylate - terminated silicone oil, which can effectively improve the heat - aging performance while improving the ring stiffness and low - temperature impact resistance of PE drain pipes, thereby obtaining a PE drain pipe with excellent weather resistance.

[0013] In some specific embodiments, the preparation raw materials of the PE - carbon black masterbatch include 50 - 60 parts by weight of PE resin, 40 - 50 parts by weight of modified carbon black, and 0.1 - 0.2 parts by weight of silicone masterbatch; among them, the modified carbon black is obtained by jointly modifying carbon black with a vinyl / allyl - type silane coupling agent and an epoxy - based silane coupling agent. In the preparation raw materials of the modified carbon black, the weight ratio of the vinyl / allyl - type silane coupling agent, the epoxy - based silane coupling agent to carbon black is (0.15 - 0.25):(0.15 - 0.25):1.

[0014] In some specific embodiments, the modified zinc oxide whiskers are obtained by jointly modifying zinc oxide whiskers with a vinyl / allyl - type silane coupling agent and an amino - silane coupling agent. In the preparation raw materials of the modified zinc oxide whiskers, the weight ratio of the vinyl / allyl - type silane coupling agent, the amino - silane coupling agent to zinc oxide whiskers is (0.3 - 0.4):(0.3 - 0.4):1.

[0015] In this application, the modified carbon black is the modified carbon black obtained by jointly modifying carbon black with a vinyl / allyl - type silane coupling agent and an epoxy - based silane coupling agent. By selecting a specific weight ratio among the vinyl / allyl - type silane coupling agent, the epoxy - based silane coupling agent and carbon black, the vinyl / allyl - type silane coupling agent and the epoxy - based silane coupling agent are simultaneously grafted onto the carbon black. The modified zinc oxide whiskers are the modified zinc oxide whiskers obtained by jointly modifying zinc oxide whiskers with a vinyl / allyl - type silane coupling agent and an amino - silane coupling agent. By selecting a specific weight ratio among the vinyl / allyl - type silane coupling agent, the amino - silane coupling agent and zinc oxide whiskers, the vinyl / allyl - type silane coupling agent and the amino - silane coupling agent are simultaneously grafted onto the zinc oxide whiskers.

[0016] Among them, the vinyl / allyl silane coupling agent on the modified carbon black can crosslink with the resin of the weather-resistant PE outer layer, improving the bonding strength between the modified carbon black and the weather-resistant PE outer layer resin, which is beneficial to improving the low-temperature embrittlement resistance and heat aging resistance of the weather-resistant PE outer layer; the epoxy silane coupling agent on the modified carbon black can chemically bond with the amino silane coupling agent on the modified zinc oxide whiskers, which can enhance the bonding strength between the anti-scaling PE inner layer and the weather-resistant PE outer layer, thereby improving the low-temperature embrittlement resistance and heat aging resistance of the PE drainage pipe. The vinyl / allyl silane coupling agent on the modified zinc oxide whiskers can crosslink with the resin of the anti-scaling PE inner layer, improving the bonding strength between the modified zinc oxide whiskers and the anti-scaling PE inner layer resin, which is beneficial to improving the low-temperature embrittlement resistance and heat aging resistance of the anti-scaling PE inner layer. After effectively improving the low-temperature embrittlement resistance and heat aging resistance of the weather-resistant PE outer layer, the anti-scaling PE inner layer, and the bonding interface between the anti-scaling PE inner layer and the weather-resistant PE outer layer, it is beneficial to obtain a PE drainage pipe with excellent low-temperature embrittlement resistance and heat aging resistance.

[0017] In some specific embodiments, the thickness ratio of the anti-scaling PE inner layer to the weather-resistant PE outer layer is (4-6):1.

[0018] In some specific embodiments, the first initiator and the second initiator are respectively at least one of benzoyl peroxide and diisopropylbenzene peroxide.

[0019] In some specific embodiments, the vinyl / allyl silane coupling agent is at least one of vinyltriethoxysilane, vinyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and γ-(methacryloyloxy)propyltriethoxysilane.

[0020] In a second aspect, a preparation method of a weather-resistant and anti-scaling PE drainage pipe provided by the present application adopts the following technical solution: A preparation method of a weather-resistant and anti-scaling PE drainage pipe includes the following steps: Put the preparation raw materials of the anti-scaling PE inner layer into extruder A according to the ratio, and melt and mix them evenly at 195-205°C to obtain an anti-scaling PE inner layer melt; Put the preparation raw materials of the weather-resistant PE outer layer into extruder B according to the ratio, and melt and mix them evenly at 195-205°C to obtain a weather-resistant PE outer layer melt; Distribute the anti-scaling PE inner layer melt to the inner layer of a two-layer co-extrusion die, distribute the weather-resistant PE outer layer melt to the outer layer of the two-layer co-extrusion die, and co-extrude them at 180-190°C, then vacuum shape, cool, and cut to obtain a weather-resistant and anti-scaling PE drainage pipe.

[0021] In some specific embodiments, in the vacuum shaping step, the vacuum degree is controlled to be -0.02 Mpa to -0.06 Mpa.

[0022] In summary, the present application at least includes the following beneficial technical effects: In the weather-resistant and scale-resistant PE drain pipe of the present application, the modified zinc oxide whiskers in the scale-resistant PE inner layer are at least obtained by modifying zinc oxide whiskers with vinyl / allyl silane coupling agents, which can improve the interfacial bonding strength between the modified zinc oxide whiskers and the resin matrix, and is beneficial to obtaining a PE scale-resistant inner layer with long-term antibacterial effects. In addition, adding a certain amount of polyethylene wax can achieve the uniform dispersion of the modified zinc oxide whiskers, which is beneficial to obtaining a scale-resistant PE inner layer with a smooth inner wall and small roughness, and reducing the attachment of scale-forming substances. That is, the present application can obtain a PE drain pipe with excellent scale resistance through the synergistic cooperation of modified zinc oxide whiskers and polyethylene wax.

[0023] In the weather-resistant PE outer layer of the present application, a PE-carbon black masterbatch capable of effectively absorbing ultraviolet rays is added, which can prevent the problem of aging of the PE drain pipe due to ultraviolet irradiation when used outdoors; adding acrylate-capped silicone oil and a second initiator, under the initiation of the second initiator, the acrylate-capped silicone oil and the second HDPE resin undergo a cross-linking reaction, which can further improve the heat aging performance of the weather-resistant PE outer layer.

[0024] The present application preferably uses a composition of acrylate-capped silicone oil A and acrylate-capped silicone oil B as the acrylate-capped silicone oil, which can effectively improve the heat aging performance while improving the ring stiffness and low-temperature impact resistance of the PE drain pipe, thereby obtaining a PE drain pipe with excellent weather resistance. Specific embodiments

[0025] The following further illustrates the present application in combination with specific experiments.

[0026] Preparation example of modified zinc oxide

Preparation example 1-1

[0027]

Preparation example 1-2

[0028]

Preparation Example 1 - 3

[0029] Preparation Example of Modified Carbon Black

Preparation Example 2 - 1

[0030]

Preparation Example 2 - 2

[0031] Examples

Example 1

[0032] In this embodiment, the preparation method of the weather-resistant and scale-resistant PE drainage pipe includes the following steps: Put the preparation raw materials of the scale-resistant PE inner layer into extruder A according to the ratio, and melt and mix them evenly at 195 - 205 °C to obtain a scale-resistant PE inner layer melt; Put the preparation raw materials of the weather-resistant PE outer layer into extruder B according to the ratio, and melt and mix them evenly at 195 - 205 °C to obtain a weather-resistant PE outer layer melt; Distribute the scale-resistant PE inner layer melt to the inner layer of the two-layer co-extrusion die, distribute the weather-resistant PE outer layer melt to the outer layer of the two-layer co-extrusion die, and co-extrude them at 180 - 190 °C. Then, shape, cool, and cut them under a vacuum degree of -0.02 Mpa to obtain a weather-resistant and scale-resistant PE drainage pipe.

[0033]

Example 2

[0034] In this embodiment, the preparation method of the weather-resistant and scale-resistant PE drainage pipe includes the following steps: Put the preparation raw materials of the scale-resistant PE inner layer into extruder A according to the ratio, and melt and mix them evenly at 195 - 205 °C to obtain a scale-resistant PE inner layer melt; Put the raw materials for preparing the weather-resistant PE outer layer into extruder B according to the ratio, melt and mix them evenly at 195 - 205 °C to obtain the weather-resistant PE outer layer melt; Distribute the anti-scaling PE inner layer melt to the inner layer of the two-layer co-extrusion die, and distribute the weather-resistant PE outer layer melt to the outer layer of the two-layer co-extrusion die, and co-extrude them at 180 - 190 °C, then shape, cool, and cut them under a vacuum of -0.06 Mpa to obtain the weather-resistant and anti-scaling PE drainage pipe.

[0035]

Example 3

Example 1

Preparation Example 1-2

[0036]

Example 4

Example 3

[0037] In this example, the raw materials for preparing the weather-resistant PE outer layer include 100 kg of the second HDPE resin (Formosa Plastics 8001), 0.002 kg of PE-carbon black masterbatch, 6.5 kg of acrylate-capped silicone oil, and 0.012 kg of diisopropylbenzene peroxide. Among them, the acrylate-capped silicone oil specifically uses acrylate-capped silicone oil A, and the structural formula of acrylate-capped silicone oil A is as follows: CH 2 =CR 1 COO(CH 2 ) 3 SiR 2 R 3 O(SiR 2 R 3 O) n SiR 2 R 3 (CH 2 ) 3 OOCCR 1 =CH 2 ; Among them, R 1 is H, R 2 , R 3 are methyl groups, and the value of n is 45.

[0038]

Example 5

Example 4

[0039] In this example, the acrylate-capped silicone oil specifically uses acrylate-capped silicone oil B, and the structural formula of acrylate-capped silicone oil B is as follows: CH 2 =CR 1 COO(CH 2 ) 3 SiR 2 R 3 O(SiR 2 R 3 O) n SiR 2 R 3 (CH 2 ) 3 OOCCR 1 =CH 2 ; Wherein, R 1 is methyl, R 2 is methyl, R 3 is phenyl, and the value of n is 45.

[0040]

Example 6

Example 3

[0041] In this example, the acrylate-capped silicone oil is a composition of acrylate-capped silicone oil A and acrylate-capped silicone oil B, and the weight ratio of acrylate-capped silicone oil A to acrylate-capped silicone oil B is 1:1.

[0042]

Example 7

Example 3

[0043] In this example, the acrylate-capped silicone oil is a composition of acrylate-capped silicone oil A and acrylate-capped silicone oil B, and the weight ratio of acrylate-capped silicone oil A to acrylate-capped silicone oil B is 3:1.

[0044]

Example 8

Example 7

[0045]

Example 9

[0046] Comparative example

Comparative Example 1

[0047]

Comparative Example 2

[0048] Performance detection test Preparation of test specimens to be tested: According to the methods described in each example and comparative example, pipes with a nominal size of 500 mm, a minimum inner diameter of 490 mm, and a nominal wall thickness of 46 mm are prepared.

[0049] Inner wall roughness coefficient: For each example and comparative example, 10 PE drainage pipes of the same size are taken to test the inner wall roughness coefficient, and the average value is taken.

[0050] Inner wall antibacterial property: The test is carried out with reference to JC / T 939-2004 "Antibacterial Properties of Antibacterial Plastic Pipes for Building Use", and the test strain is Staphylococcus aureus.

[0051] Ring stiffness: The test is carried out with reference to GB / T9647-2015 "Determination of Ring Stiffness of Thermoplastic Pipe".

[0052] Ring flexibility: The test is carried out with reference to GB / T39385-2020 "Plastics piping systems - Determination of the ring flexibility of thermoplastic pipes".

[0053] Impact performance: For each example and comparative example, 50 PE drainage pipes of the same size are taken, and a falling hammer with a weight of 1.5 kg is used to impact the PE drainage pipe at a height of 1.0 m, and the number of damaged pipes (including the number of cracks, delaminations, and bubbles) is calculated. Among them, when the damage rate ≤ 10%, it is qualified.

[0054] Low-temperature impact performance: For each example and comparative example, 50 PE drainage pipes of the same size are taken, left standing in an environment of -10 °C for 168 h, then placed at room temperature, and a falling hammer with a weight of 1.5 kg is used to impact the PE drainage pipe at a height of 1.0 m, and the number of damaged pipes (including the number of cracks, delaminations, and bubbles) is calculated. Among them, when the damage rate ≤ 10%, it is qualified.

[0055] Thermal aging impact performance: For each of the examples and comparative examples, 10 PE drainage pipes of the same size were taken. After standing in an environment of 80 °C for 168 h, they were cooled to room temperature. A falling hammer weighing 1.5 kg was used to impact the PE drainage pipes at a height of 1.0 m, and the number of damaged pipes (including the number of cracks, delaminations, and blisters) was calculated. Among them, a damage rate ≤ 10% was considered qualified.

[0056] Table 1

[0057] Table 2

[0058] Table 3

[0059] Combined with the content recorded in Examples 1-8 and Tables 1-3, it can be seen that: The inner wall roughness of the weather-resistant and scale-resistant PE drainage pipes provided in Examples 1-8 of the present application is low, the antibacterial property is good, the ring stiffness and ring flexibility are high, and it has good impact performance, low-temperature impact performance, and thermal aging impact performance, and the comprehensive performance is excellent.

[0060] Combined with the content recorded in Example 1 and Comparative Examples 1-2 and Tables 1-3, it can be seen that: When the modified zinc oxide whiskers are modified alone with a vinyl-free silane coupling agent or the addition of polyethylene wax is omitted, it is not conducive to the uniform dispersion of the modified zinc oxide, and it is difficult to obtain a PE drainage pipe with a wall roughness coefficient lower than 0.011. In addition, the antibacterial persistence of the PE drainage pipe also decreases, and scaling problems are likely to occur after long-term use.

[0061] Combined with the content recorded in Example 1 and Example 3 and Tables 1-3, it can be seen that: In the PE scale-resistant inner layer, the product obtained by modifying zinc oxide whiskers with a combination of vinyltriethoxysilane and amino silane coupling agent KH550 can further improve the ring stiffness, low-temperature impact resistance, and thermal aging impact resistance of the PE drainage pipe, that is, it is beneficial to further improve the strength and weather resistance of the PE drainage pipe.

[0062] Combined with the content recorded in Example 3 and Examples 4-8 and Tables 1-3, it can be seen that: In the weather-resistant PE outer layer, adding acrylate-capped silicone oil or vinyl-capped silicone oil to crosslink and modify the matrix resin of the weather-resistant PE outer layer is beneficial to improving the heat aging resistance of the PE drainage pipe. Among them, when the acrylate-capped silicone oil is a composition with a weight ratio of acrylate-capped silicone oil A to acrylate-capped silicone oil B of 3:1, it can effectively improve the heat aging resistance while improving the ring stiffness and low-temperature impact resistance of the PE drainage pipe, thereby obtaining a PE drainage pipe with excellent weather resistance.

[0063] It can be seen from the combination of Example 7 and Example 9 and the content recorded in Tables 1-3 that the weight ratio of the two silane coupling agents in the modified zinc oxide whiskers and the modified carbon black affects the wall roughness coefficient, ring stiffness, low-temperature impact resistance, and heat-aging impact resistance of the PE drainage pipe.

[0064] This specific implementation manner is only an interpretation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this specific implementation manner as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A weather-resistant and anti-scale PE drainage pipe, characterized by: The invention comprises an anti-fouling PE inner layer and a weather-resistant PE outer layer, wherein the raw materials for preparing the anti-fouling PE inner layer comprise 100 parts by weight of a first HDPE resin, 4.5-5.5 parts by weight of modified zinc oxide whiskers, 1-2 parts by weight of polyolefin wax and 0.005-0.01 parts by weight of a first initiator, wherein the modified zinc oxide whiskers are obtained by modifying the zinc oxide whiskers at least by using a vinyl / propylene silane coupling agent; and the raw materials for preparing the weather-resistant PE outer layer comprise 100 parts by weight of a second HDPE resin and 0.002-0.004 parts by weight of PE-carbon black masterbatch, 6.5-7.5 parts by weight of acrylate-terminated silicone oil and 0.01-0.015 parts by weight of a second initiator.

2. A weather-resistant and anti-scale PE drainage pipe according to claim 1, characterized in that: The modified zinc oxide whisker has a diameter of 30-40 nm, a length of 200-300 nm, and an aspect ratio of 5-10.

3. The weather-resistant and anti-scale PE drainage pipe according to claim 1, characterized in that: The structural formula of the acrylate-terminated silicone oil is as follows: <h2 style=";text-align:left;direction:ltr">CH2=Cr1COO(CH2)3SiR2R3O(SiR2R3O)<h2 style=";text-align:left;direction:ltr"> n <h2 style=";text-align:left;direction:ltr"> SiR2R3(CH2)3OOCCR1=CH2; Wherein, R1 is H or alkyl, R2 and R3 are alkyl or phenyl, and the value range of n is 40-50.

4. The weather-resistant and anti-scale PE drainage pipe according to claim 3, characterized in that: The acrylate-terminated silicone oil comprises acrylate-terminated silicone oil A and acrylate-terminated silicone oil B, wherein the weight ratio of the acrylate-terminated silicone oil A to the acrylate-terminated silicone oil B is (3-4):1; wherein, in the acrylate-terminated silicone oil A, R1 is H, and R2 and R3 are methyl groups; and in the acrylate-terminated silicone oil B, R1 is methyl, R2 is methyl, and R3 is phenyl group.

5. The weather-resistant and anti-scale PE drainage pipe according to claim 1, characterized in that: The raw materials for preparing the PE-carbon black masterbatch include 50-60 parts by weight of PE resin, 40-50 parts by weight of modified carbon black and 0.1-0.2 parts by weight of silicone masterbatch; wherein the modified carbon black is obtained by modifying carbon black with a vinyl / propylene silane coupling agent and an epoxy silane coupling agent, and in the raw materials for preparing the modified carbon black, the weight ratio of the vinyl / propylene silane coupling agent, the epoxy silane coupling agent and the carbon black is (0.15-0.25):(0.15-0.25):

1.

6. The weather-resistant and anti-scale PE drainage pipe according to claim 5, characterized in that: The modified zinc oxide whisker is obtained by modifying zinc oxide whiskers with a vinyl / propylene silane coupling agent and an aminosilane coupling agent. In the raw materials for preparing the modified zinc oxide whisker, the weight ratio of the vinyl / propylene silane coupling agent, the aminosilane coupling agent and the zinc oxide whisker is (0.3-0.4): (0.3-0.4):

1.

7. A weather-resistant and anti-scale PE drainage pipe according to any one of claims 1 to 6, characterized in that: The thickness ratio of the anti-fouling PE inner layer to the weather-resistant PE outer layer is (4-6):

1.

8. A method for preparing a weather-resistant and anti-scale PE drainage pipe according to any one of claims 1 to 7, characterized in that: The following steps are involved: The raw materials for preparing the anti-fouling PE inner layer are put into the extruder A according to the ratio, and melted evenly at 195-205° C. to obtain the anti-fouling PE inner layer melt; The raw materials for preparing the weather-resistant PE outer layer are put into the extruder B according to the ratio, and melted evenly at 195-205° C. to obtain a weather-resistant PE outer layer melt; The anti-scale PE inner layer melt is distributed to the inner layer of a two-layer co-extrusion mold, and the weather-resistant PE outer layer melt is distributed to the outer layer of a two-layer co-extrusion mold, and composite co-extruded at 180-190°C, and then vacuum-formed, cooled, and cut to obtain a weather-resistant and anti-scale PE drainage pipe.

9. The method for preparing a weather-resistant and anti-scale PE drainage pipe according to claim 8, characterized in that: In the vacuum shaping step, the vacuum degree is controlled to be -0.02Mpa~-0.06Mpa.

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