Ultra-light self-cleaning microporous polyethylene socket-and-spigot drain pipe and preparation method thereof

Abstract

The invention discloses an ultra-light self-cleaning microporous polyethylene socket-and-spigot drain pipe and a preparation method thereof, and belongs to the technical field of drain pipes for buildings, the ultra-light self-cleaning microporous polyethylene socket-and-spigot drain pipe comprises a pipe body and a socket joint, and the socket joint is arranged at a port of the pipe body through an extrusion process; the pipe body is composed of an outer layer, a middle layer and an inner layer. The outer layer is made of an ultra-high molecular weight polyethylene composite material; the middle layer is made of a high-density polyethylene foaming composite material; the inner layer is made of a polyethylene / silicon dioxide / spandex fiber composite material; and the socket joint is made of a medium-density polyethylene material. The three-layer structure and the connector are all prepared by modifying a polyethylene material, the cohesiveness between layers and between the pipe body and the connector is high when the pipe body is prepared through extrusion, integration of the pipe body and the connector is achieved, the characteristics of different composite materials are fully combined, and it is guaranteed that all properties of the drainage pipe are improved while the cost is reduced; and the whole process does not have complicated procedures, and the practical applicability is high.

Description

Technical Field

[0001] The invention belongs to the technical field of drainage pipes for buildings, and specifically relates to an ultra-light self-cleaning microporous polyethylene socket-type drainage pipe and a preparation method thereof. Background Art

[0002] With the vigorous development of municipal engineering, the demand for water supply and drainage pipes is increasing. The water supply and drainage pipes usually involved include corrugated pipes, spiral pipes, high-density polyethylene solid wall drainage pipes, high-density polyethylene solid wall water supply pipes, steel belt pipes, etc. The above pipes have obvious advantages and disadvantages due to their application fields and structural composition. For example: due to the existing market verification, the quality of corrugated pipes is difficult to guarantee, and its ring flexibility performance is difficult to guarantee 100%. Because of its spiral square tube structure, the sealing of the port of spiral pipes is difficult to guarantee. High-density polyethylene solid wall drainage pipes are mostly produced in the market with recycled materials, and their surface roughness is difficult to guarantee, which affects the flow rate of the medium in the pipe body. The price of high-density polyethylene solid wall water supply pipes is too high, and it is difficult to promote them in the drainage field without special needs. Since the steel belt pipe is a composite pipe of steel belt and polyethylene, the volatility of the composite process directly affects the product stability of the finished steel belt pipe.

[0003] Based on the simple shortcomings analysis of the above products, it is of great significance to develop a pipe with excellent ring stiffness, excellent ring flexibility, smooth inner wall, wear-resistant and unbreakable outer wall, lightweight pipe body, convenient construction and high cost performance. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-light self-cleaning microporous polyethylene socket-type drainage pipe and a preparation method thereof, so as to improve the comprehensive performance of the polyethylene drainage pipe and enhance its practical applicability.

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

[0006] The present invention provides an ultra-light self-cleaning microporous polyethylene spigot and socket type drainage pipe, the ultra-light self-cleaning microporous polyethylene spigot and socket type drainage pipe comprises a pipe body and a socket joint, and one end of the pipe body is provided with a socket joint by an extrusion injection process;

[0007] The tube body is composed of an outer layer, a middle layer and an inner layer;

[0008] The outer layer is an ultra-high molecular weight polyethylene composite material;

[0009] The middle layer is a high-density polyethylene foam composite material;

[0010] The inner layer is a polyethylene / silicon dioxide / spandex fiber composite material;

[0011] The socket joint is made of medium-density polyethylene material.

[0012] Furthermore, the ultra-high molecular weight polyethylene composite material comprises the following raw materials in parts by mass:

[0013] 30-50 parts of ultra-high molecular weight polyethylene, 10-24 parts of medium density polyethylene, 6-12 parts of polyphthalamide, 3-8 parts of mica, 2-7 parts of talc, and 1-2 parts of coupling agent.

[0014] Furthermore, the high-density polyethylene foam composite material comprises the following raw materials by weight: 80-100 parts of high-density polyethylene, 24-30 parts of hydroxyapatite, 3.0-9.6 parts of calcium carbonate, 1.5-4.8 parts of sodium bicarbonate, and 0.5-1.6 parts of magnesium carbonate.

[0015] Furthermore, the polyethylene / silicon dioxide / spandex fiber composite material comprises the following raw materials in parts by mass:

[0016] 50-70 parts of polyethylene, 10-15 parts of silicon dioxide, 5-8 parts of spandex fiber, 0.8-2.1 parts of coupling agent, and 5-7 parts of plasticizer.

[0017] Furthermore, the coupling agent in the ultra-high molecular weight polyethylene composite material is at least one of a titanate coupling agent, an aluminate coupling agent, stearic acid, sodium stearate and a KH-550 silane coupling agent.

[0018] Furthermore, the coupling agent in the polyethylene / silicon dioxide / spandex fiber composite material is at least one of KH-500 silane coupling agent and KH-550 silane coupling agent.

[0019] Furthermore, the plasticizer in the polyethylene / silicon dioxide / spandex fiber composite material is at least one of tributyl citrate, tri-n-hexyl citrate and cyclohexane dicarboxylate.

[0020] Tributyl citrate, tri-n-hexyl citrate and cyclohexanedicarboxylate are all environmentally friendly plasticizers, which are non-toxic and highly safe and will not cause secondary pollution to water quality.

[0021] The present invention also provides a method for preparing the ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe as described above, comprising the following steps:

[0022] Step 1: Prepare polyethylene / silicon dioxide / spandex fiber composite materials, mix and stir the coupling agent, deionized water and anhydrous ethanol to fully hydrolyze the coupling agent, add silica to n-butanol for ultrasonic dispersion to form a silica dispersion, heat the silica dispersion in an oil bath, add the coupling agent hydrolyzate dropwise under constant temperature stirring conditions, centrifuge and wash after the modification reaction is completed, and dry to obtain modified silica. Put the modified silica, spandex fiber, plasticizer and polyethylene into a high-speed mixer and mix them evenly, put them into a screw extruder for melt extrusion and granulation, and the extruder temperature is 150-200°C to obtain a polyethylene / silicon dioxide composite material;

[0023] Since silica is an inorganic substance and polyethylene is an organic substance, the composite of the two requires surface modification of silica. Silica particles are prone to agglomeration and are difficult to disperse. The presence of hydroxyl functional groups on the surface of silica powder also makes it hydrophilic and oleophobic, which hinders its good dispersion in organic matter. Coupling agent treatment causes chemical bonding between the hydroxyl groups on the surface of silica and the silane coupling agent, so that there are larger steric hindrances and long-chain molecules on the surface of the modified particles, allowing them to composite with polyethylene. The long-chain molecules grafted on the modified particles are physically entangled with the long-chain molecules of polyethylene to improve dispersibility. The hydrophobicity of the surface of the composite silica can be well transferred to the polyethylene material, thereby improving the hydrophobic properties of the composite material, that is, increasing the hydrophobicity of the inner wall of the tube body, improving the flow smoothness of the liquid medium inside the tube body, and reducing the friction coefficient. Spandex fiber is a fiber made of polymerized carbamate. It basically does not have ionic groups and strong hydrophilic groups in the molecule, but has aromatic rings and hydrophobic methylene chains, and has certain hydrophobic properties. Spandex fiber has excellent elasticity, good heat resistance, chemical resistance and wear resistance. When it is added to polyethylene material, on the one hand, the elasticity and hydrophobicity of the fiber itself can improve the ring stiffness and hydrophobicity of the composite material. On the other hand, the melting point of spandex fiber is 230-260℃, and the original fiber structure will not be destroyed during the polyethylene extrusion and melting process. The fiber forms entanglement with polyethylene and silica materials, ensuring the tightness of the bonding between different materials in the composite material and improving the comprehensive performance of the material.

[0024] Step 2: preparing a high-density polyethylene foam composite material, putting high-density polyethylene, hydroxyapatite, calcium carbonate, magnesium carbonate and sodium bicarbonate into a high-speed mixer, mixing at a temperature below 40° C. for 10-20 minutes to obtain a high-density polyethylene foam composite material;

[0025] High-density polyethylene is physically mixed with hydroxyapatite, calcium carbonate, magnesium carbonate and sodium bicarbonate at low temperature to form a modified composite material. The composite material will be plasticized by heat during the subsequent extrusion process, and carbon dioxide will be decomposed at this time to play a foaming role. The normal pipe density is between 0.95-0.97. By controlling the dosage of calcium carbonate, magnesium carbonate and sodium bicarbonate, the density after foaming is between 0.75-0.8, which can better save costs and achieve lightweight pipes. In order to ensure strength, the density value is controlled not too low. Hydroxyapatite has a high elastic modulus. Adding hydroxyapatite to the composite material can increase the elastic modulus and make the pipe have a larger ring stiffness value.

[0026] Step 3, preparing an ultra-high molecular weight polyethylene composite material, putting a coupling agent, mica and talc into a high-speed mixer, the mixing temperature is 50-60°C, mixing for 20-30 minutes to obtain a modified mica and modified talc mixture, and putting the modified mica and modified talc mixture, ultra-high molecular weight polyethylene, medium-density polyethylene and polyphthalamide into a high-speed mixer for stirring and mixing. After mixing evenly, put it into a screw extruder for melt extrusion granulation, and the extruder temperature is 180-200°C to obtain an ultra-high molecular weight polyethylene composite material;

[0027] Ultra-high molecular weight polyethylene is a polymer compound that is difficult to process, and has super wear resistance, self-lubrication, high strength, stable chemical properties, and strong anti-aging performance. Pure ultra-high molecular weight polyethylene products are difficult to melt, and the fluidity after melting is poor, which is not conducive to processing. In order to ensure that this material can be formed into pipes by extrusion molding, the material is mixed and modified to obtain an ultra-high molecular weight polyethylene composite material. Medium-density polyethylene and polyphthalamide have high fluidity and good processability. The modified mica and modified talc mixture can improve the wear resistance of the material and have good compatibility with the polymer matrix. The composite modification not only ensures the wear resistance of the material, but also improves the processability of the material.

[0028] Step 4: Prepare a pipe body, put the polyethylene / silicon dioxide / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material into a three-layer co-extrusion extruder, extrude the polyethylene / silicon dioxide / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material simultaneously according to the inner layer, the middle layer and the outer layer through three-layer co-extrusion, and cool and shape to obtain the pipe body of the ultra-light self-cleaning microporous polyethylene socket-type drainage pipe;

[0029] During the extrusion process of the high-density polyethylene foam composite material, due to the stress, the polyethylene forms a tightly arranged microfiber structure and forms a layered structure with hydroxyapatite. This structure enables the middle layer to maintain structural continuity while having a certain space gap, ensuring that calcium carbonate, magnesium carbonate and sodium bicarbonate can better release carbon dioxide and form an enlarged pore structure.

[0030] Step 5. The outer wall of the pipe body port of the ultralight self-cleaning microporous polyethylene socket-type drainage pipe is connected to the socket joint molding mold, the outer wall is heated and melted, and the medium-density polyethylene is melted and injected with high pressure to fill the socket joint molding mold. After cooling and molding, the socket joint molding mold is separated to obtain the ultralight self-cleaning microporous polyethylene socket-type drainage pipe.

[0031] Furthermore, in step 1, the mass ratio of the coupling agent, deionized water and anhydrous ethanol mixed and stirred is 1-2:1:10, the mass ratio of silica and n-butanol is 1:15-20, the temperature of the silica dispersion heated in an oil bath is 80-100°C, the coupling agent hydrolyzate is added dropwise to the silica dispersion according to 8-14% of the coupling agent by mass of silica, and the modification reaction time is 5-8h.

[0032] During the modification reaction, the reaction time is short, the effective collision probability between the coupling agent and silica is reduced, and the effective active sites are not fully reacted. If the reaction time is too long, the effective active sites on the particle surface have been occupied, and the self-polymerization reaction of the coupling agent also occupies a large proportion, and the concentration of the silane coupling agent that can participate in the grafting reaction is reduced. If the temperature is low, the chemical energy required for bond breaking during the grafting modification reaction is insufficient, and if the temperature is too high, the collision probability between silane coupling agent molecules is relatively high, resulting in a large proportion of the self-polymerization reaction of the silane coupling agent. If the proportion of coupling agent is too large, the effective collision probability between the coupling agents will increase, and self-polymerization reaction will occur. If the proportion of coupling agent is too small, there will be insufficient reaction between the coupling agent and the active sites on the silica surface. In order to ensure that the modified silica has the best hydrophobic properties, it is necessary to strictly control the parameters during the modification reaction.

[0033] Furthermore, the extrusion temperature of each layer in the three-layer co-extrusion extruder is set to:

[0034] The extrusion temperature of the inner layer is 150-180°C, the extrusion temperature of the middle layer is 160-200°C, and the extrusion temperature of the outer layer is 180-210°C.

[0035] According to the melting characteristics of the composite materials of different layers, the extrusion temperature needs to be strictly controlled. Too high a temperature will lead to degradation of the material, while too low a temperature will lead to insufficient melting, poor fluidity of the material, and inability to obtain a uniform molding material.

[0036] Beneficial effects of the present invention:

[0037] (1) With regard to the wear resistance of the outer wall, the present invention adopts an ultra-high molecular weight polyethylene composite material as the outer coating layer, which has excellent wear resistance and processability. Since it and the middle layer are both made of polyethylene materials, they can have good compatibility and adhesion.

[0038] (2) In order to achieve lightweight and high ring stiffness of the pipe body, high-density polyethylene is mixed with hydroxyapatite, calcium carbonate, magnesium carbonate and sodium bicarbonate in a certain proportion and used as the middle layer. Since the polyethylene body is modified with hydroxyapatite, its elastic modulus is relatively high and can provide a larger ring stiffness value. At the same time, the addition of calcium carbonate, magnesium carbonate and sodium bicarbonate decomposes to produce carbon dioxide, which ensures that the internal structure of the middle layer of the pipe is evenly distributed in the shape of a honeycomb, presenting a pore structure. This not only reduces the density of the middle layer and greatly reduces the weight of the pipe body itself, but also the uniform distribution of the honeycomb pores can provide greater support for the ring stiffness of the pipe body itself from a structural perspective.

[0039] (3) In order to make the inner wall of the pipe smooth and flat, a polyethylene / silicon dioxide / spandex fiber composite material is used for the inner layer of the pipe. Modified silica is added to the composite material to increase the hydrophobicity of the inner wall, improve the flow smoothness of the liquid medium inside the pipe, and reduce the friction coefficient. The added spandex fiber can further improve the comprehensive performance of the composite material from the fiber structure and its own hydrophobic high elastic properties.

[0040] (4) Regarding the convenience of construction, solid wall pipes are currently mainly fixed by hot melt welding or flange welding, which is affected by the construction environment and welding process and is subject to greater constraints. In order to improve this situation, the present invention chooses to prepare a socket joint at the port of the pipe body, changing the traditional welding butt method to a socket method, which greatly facilitates construction.

[0041] (5) The present invention prepares an ultra-light self-cleaning microporous polyethylene socket-type drainage pipe by combining a three-layer structure of the pipe body and a socket joint. The three-layer structure and the joint are prepared by modifying the polyethylene material. When the pipe body is prepared by extrusion, the adhesion between the layers and between the pipe body and the joint is strong, so the pipe body and the joint are integrated. The characteristics of different composite materials are fully combined to reduce the cost while ensuring the improvement of various performances of the drainage pipe. The overall process does not have complicated steps and has strong practical applicability. DETAILED DESCRIPTION

[0042] 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.

[0043] Example 1

[0044] The present embodiment provides an ultra-light self-cleaning microporous polyethylene socket-type drainage pipe, including a pipe body and a socket joint. The port of the pipe body is provided with a socket joint by an extrusion process. The pipe body is composed of an outer layer, a middle layer and an inner layer. The outer layer is an ultra-high molecular weight polyethylene composite material, the middle layer is a high-density polyethylene foam composite material, the inner layer is a polyethylene / silicon dioxide / spandex fiber composite material, and the socket joint is a medium-density polyethylene material.

[0045] The ultra-high molecular weight polyethylene composite material includes the following raw materials by weight:

[0046] 50 parts of ultra-high molecular weight polyethylene, 10 parts of medium density polyethylene, 6 parts of polyphthalamide, 3 parts of mica, 2 parts of talc, and 1 part of titanate coupling agent.

[0047] The high-density polyethylene foam composite material includes the following raw materials by weight:

[0048] 100 parts of high-density polyethylene, 24 parts of hydroxyapatite, 3.0 parts of calcium carbonate, 1.5 parts of sodium bicarbonate, and 0.5 parts of magnesium carbonate.

[0049] The polyethylene / silicon dioxide / spandex fiber composite material includes the following raw materials by weight:

[0050] 70 parts of polyethylene, 10 parts of silicon dioxide, 5 parts of spandex fiber, 0.8 parts of KH-500 silane coupling agent, and 7 parts of tributyl citrate.

[0051] The specific steps for preparing the ultra-light self-cleaning microporous polyethylene socket-type drainage pipe are as follows:

[0052] Step 1: Prepare polyethylene / silicon dioxide / spandex fiber composite material, mix and stir KH-500 silane coupling agent, deionized water and anhydrous ethanol in a mass ratio of 1:1:10, fully hydrolyze KH-500 silane coupling agent, add silica to n-butanol for ultrasonic dispersion to form silica dispersion, the mass ratio of silica to n-butanol is 1:15, heat silica dispersion to 90°C in oil bath, add coupling agent hydrolyzate dropwise under constant temperature stirring conditions, add dropwise according to the coupling agent accounting for 8% of silica mass, modify reaction for 6h, centrifuge and wash after completion, and dry to obtain modified silica. Put modified silica, spandex fiber, plasticizer and polyethylene into a high-speed mixer and mix evenly, put into a screw extruder for melt extrusion granulation, and the extruder temperature is 150-200°C to obtain a polyethylene / silicon dioxide composite material.

[0053] Step 2: prepare a high-density polyethylene foam composite material, put high-density polyethylene, hydroxyapatite, calcium carbonate, magnesium carbonate and sodium bicarbonate into a high-speed mixer, mix at a temperature of 35° C., mix for 15 minutes, and obtain a high-density polyethylene foam composite material.

[0054] Step 3, prepare an ultra-high molecular weight polyethylene composite material, put the titanate coupling agent, mica and talc into a high-speed mixer, the mixing temperature is 60 ° C, and after mixing for 30 minutes, a modified mica and modified talc mixture is obtained, and the modified mica and modified talc mixture, ultra-high molecular weight polyethylene, medium-density polyethylene and polyphthalamide are put into a high-speed mixer and stirred and mixed. After mixing evenly, put it into a screw extruder for melt extrusion and granulation. The extruder temperature is 180-200 ° C to obtain an ultra-high molecular weight polyethylene composite material.

[0055] Step 4, prepare the pipe body, put the polyethylene / silica / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material into a three-layer co-extrusion extruder, and extrude the polyethylene / silica / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material simultaneously according to the inner layer, the middle layer and the outer layer through three-layer co-extrusion, set the inner layer extrusion temperature to 150-180°C, the middle layer extrusion temperature to 160-200°C and the outer layer extrusion temperature to 180-210°C, and cool and mold to obtain the pipe body of the ultra-light self-cleaning microporous polyethylene socket-type drainage pipe.

[0056] Step 5. The outer wall of the pipe body port of the ultralight self-cleaning microporous polyethylene socket-type drainage pipe is connected to the socket joint molding mold, the outer wall is heated and melted, and the medium-density polyethylene is melted and injected with high pressure to fill the socket joint molding mold. After cooling and molding, the socket joint molding mold is separated to obtain the ultralight self-cleaning microporous polyethylene socket-type drainage pipe.

[0057] Embodiment 2-5

[0058] The only difference from Example 1 is that the proportions of the components of the inner layer polyethylene / silicon dioxide / spandex fiber composite material are different. Other conditions and steps are the same as Example 1. The specific proportions of raw materials are shown in Table 1.

[0059] Table 1

[0060]

[0061] Embodiment 6-9

[0062] The only difference from Example 4 is that the proportions of the components in the middle layer high-density polyethylene foam composite material are different. Other conditions and steps are the same as Example 4. The specific proportions of raw materials are shown in Table 2.

[0063] Table 2

[0064]

[0065] Examples 10-13

[0066] The only difference from Example 8 is that the proportions of the components of the outer layer ultra-high molecular weight polyethylene composite material are different. Other conditions and steps are the same as Example 8. The specific proportions of raw materials are shown in Table 3.

[0067] Table 3

[0068]

[0069]

[0070] Comparative Example 1

[0071] Compared with Example 1, the drainage pipe prepared in this comparative example does not have a three-layer structure, but is a single-layer structure drainage pipe. The polyethylene drainage pipe is prepared according to the preparation method of Example 3 in the Chinese invention patent publication number CN112980082A.

[0072] Comparative Example 2

[0073] Compared with Example 1, the drainage pipe prepared in this comparative example does not have a three-layer structure, but is a double-layer structure drainage pipe. The drainage pipe is prepared according to the preparation method of Example 1 in the patent publication number CN114889228A.

[0074] The performance tests were performed on the drainage pipes prepared in Examples 1 to 13 and Comparative Examples 1 to 2. The results are shown in Table 4.

[0075] The wear index test refers to "HG / T 6046-2022 General Requirements for Wear-Resistant Products Made of Injection-Molding Grade Ultra-High Molecular Weight Polyethylene Resin" to test the wear resistance of the outer wall surface of the pipe body.

[0076] The ring stiffness test is carried out in accordance with "GBT9647-2015 Determination of Ring Stiffness of Thermoplastic Plastic Pipes".

[0077] The impact strength test is conducted in accordance with "CJ / T250-2018 High-density Polyethylene (HDPE) Pipes and Fittings for Building Drainage".

[0078] The tensile yield stress test is conducted with reference to GB / T 8804.3-2003 Determination of tensile properties of thermoplastic pipes Part 3 Polyolefin pipes.

[0079] The DSA100 drop shape analyzer was used to test the water contact angle of the inner wall surface of the tube.

[0080] Table 4

[0081]

[0082]

[0083] It can be seen from Table 1 that the comprehensive performance of the drain pipe prepared in the embodiment is better than that of Comparative Example 1 and Comparative Example 2. Although the drain pipe with a single-layer structure in Comparative Example 1 has auxiliary resin and composite filler added to the material to enhance the impact resistance, its hydrophobicity is obviously poor, and because the density of its filler and auxiliary resin is obviously high, the density of its drain pipe is relatively large, which is not conducive to the lightweight of the pipe. The material of the double-layer structure in Comparative Example 2 is the same, and its main raw material is polyvinyl chloride resin, which is added with nano and whisker particles to toughen and improve the ring stiffness of the pipe, but it only starts from the material itself, and does not improve the internal structure of the material, and the comprehensive performance is still not as good as Example 1. In Examples 1 to 3, increasing the proportion of modified silica can enhance the hydrophobicity of the inner layer of the pipe body to a certain extent, but it will also increase the density of the drain pipe. In Example 2, when the mass fraction of silica is 12 parts, the hydrophobicity is the best. Examples 4 and 5 further adjust the proportion of spandex fibers in the inner layer on the basis of Example 2. The amount of spandex fibers increases, and the hydrophobicity and elastic properties of the material are enhanced. However, in Example 5, too much spandex fibers will cause surface unevenness on the surface of the inner layer, resulting in a decrease in hydrophobicity. According to the proportion of the inner layer material in Example 4, the proportion of the middle layer is gradually adjusted in Examples 6-9. The content of hydroxyapatite in Examples 6 and 7 increases, and the elastic modulus of the material increases, which is correspondingly reflected in the ring stiffness and tensile yield stress of the material. The ring stiffness and tensile yield stress are increased, but due to the high density of hydroxyapatite, it will affect the lightweight of the drain pipe. Comprehensive consideration is given to further increase the proportion of the foaming auxiliary materials calcium carbonate, magnesium carbonate and sodium bicarbonate in the middle layer on the basis of Example 6. Due to the change in the pore structure of the middle layer caused by foaming, the drain pipe prepared in Examples 7 and 8 not only reduces the density, but also enhances the ring stiffness and tensile yield stress. Example 10-Example 13 is an adjustment of the proportion of components in the outer layer ultra-high molecular weight polyethylene composite material, wherein Example 10 and Example 11 reduce the proportion of ultra-molecular weight polyethylene. Although the performance of the pipe body is slightly reduced, its fluidity is better during processing. Example 12 and Example 13 increase the content of modified mica and modified talcum powder, and the wear resistance of the outer wall of the drain pipe is significantly improved.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0085] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe, characterized in that: The ultra-light self-cleaning microporous polyethylene socket-type drainage pipe comprises a pipe body and a socket joint, and the port of the pipe body is provided with a socket joint by an extrusion process; the pipe body is composed of an outer layer, an intermediate layer and an inner layer; the outer layer is an ultra-high molecular weight polyethylene composite material; the intermediate layer is a high-density polyethylene foam composite material; the inner layer is a polyethylene / silicon dioxide / spandex fiber composite material; and the socket joint is a medium-density polyethylene material.

2. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to claim 1 is characterized in that: The ultra-high molecular weight polyethylene composite material comprises the following raw materials in parts by mass: 30-50 parts of ultra-high molecular weight polyethylene, 10-24 parts of medium density polyethylene, 6-12 parts of polyphthalamide, 3-8 parts of mica, 2-7 parts of talc, and 1-2 parts of coupling agent.

3. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to claim 1, characterized in that: The high-density polyethylene foam composite material comprises the following raw materials by weight: 80-100 parts of high-density polyethylene, 24-30 parts of hydroxyapatite, 3.0-9.6 parts of calcium carbonate, 1.5-4.8 parts of sodium bicarbonate, and 0.5-1.6 parts of magnesium carbonate.

4. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drain pipe according to claim 1, characterized in that: The polyethylene / silicon dioxide / spandex fiber composite material comprises the following raw materials by weight: 50-70 parts of polyethylene, 10-15 parts of silicon dioxide, 5-8 parts of spandex fiber, 0.8-2.1 parts of coupling agent, and 5-7 parts of plasticizer.

5. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to claim 1, characterized in that: The coupling agent in the ultra-high molecular weight polyethylene composite material is at least one of a titanate coupling agent, an aluminate coupling agent, stearic acid, sodium stearate and a KH-550 silane coupling agent.

6. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to claim 1, characterized in that: The coupling agent in the polyethylene / silicon dioxide / spandex fiber composite material is at least one of a KH-500 silane coupling agent and a KH-550 silane coupling agent.

7. The ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to claim 1, characterized in that: The plasticizer in the polyethylene / silicon dioxide / spandex fiber composite material is at least one of tributyl citrate, tri-n-hexyl citrate and cyclohexane dicarboxylate.

8. A method for preparing an ultra-light self-cleaning microporous polyethylene spigot-and-socket drainage pipe according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: preparing a polyethylene / silicon dioxide / spandex fiber composite material, mixing a coupling agent, deionized water and anhydrous ethanol to fully hydrolyze the coupling agent, adding silicon dioxide to n-butanol for ultrasonic dispersion to form a silicon dioxide dispersion, heating the silicon dioxide dispersion in an oil bath, adding the coupling agent hydrolyzate dropwise under constant temperature stirring conditions, centrifugally washing after the modification reaction is completed, and drying to obtain modified silicon dioxide, and putting the modified silicon dioxide, spandex fiber, plasticizer and polyethylene into a high-speed mixer to mix evenly, and putting them into a screw extruder for melt extrusion and granulation, and the extruder temperature is 150-200° C. to obtain a polyethylene / silicon dioxide composite material; Step 2: preparing a high-density polyethylene foam composite material, putting high-density polyethylene, hydroxyapatite, calcium carbonate, magnesium carbonate and sodium bicarbonate into a high-speed mixer, mixing at a temperature below 40° C. for 10-20 minutes to obtain a high-density polyethylene foam composite material; Step 3, preparing an ultra-high molecular weight polyethylene composite material, putting a coupling agent, mica and talc into a high-speed mixer, the mixing temperature is 50-60°C, mixing for 20-30 minutes to obtain a modified mica and modified talc mixture, and putting the modified mica and modified talc mixture, ultra-high molecular weight polyethylene, medium-density polyethylene and polyphthalamide into a high-speed mixer for stirring and mixing. After mixing evenly, put it into a screw extruder for melt extrusion granulation, and the extruder temperature is 180-200°C to obtain an ultra-high molecular weight polyethylene composite material; Step 4: Prepare a pipe body, put the polyethylene / silicon dioxide / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material into a three-layer co-extrusion extruder, extrude the polyethylene / silicon dioxide / spandex fiber composite material, the high-density polyethylene foam composite material and the ultra-high molecular weight polyethylene composite material simultaneously according to the inner layer, the middle layer and the outer layer through three-layer co-extrusion, and cool and shape to obtain the pipe body of the ultra-light self-cleaning microporous polyethylene socket-type drainage pipe; Step 5. The outer wall of the pipe body port of the ultralight self-cleaning microporous polyethylene socket-type drainage pipe is connected to the socket joint molding mold, the outer wall is heated and melted, and the medium-density polyethylene is melted and injected with high pressure to fill the socket joint molding mold. After cooling and molding, the socket joint molding mold is separated to obtain the ultralight self-cleaning microporous polyethylene socket-type drainage pipe.

9. The method for preparing an ultra-light self-cleaning microporous polyethylene spigot-and-socket type drainage pipe according to claim 8, characterized in that: In step 1, the mass ratio of the coupling agent, deionized water and anhydrous ethanol mixed and stirred is 1-2:1:10, the mass ratio of silica and n-butanol is 1:15-20, the temperature of the silica dispersion heated in an oil bath is 80-100°C, the coupling agent hydrolyzate is added dropwise to the silica dispersion according to 8-14% of the coupling agent by mass of silica, and the modification reaction time is 5-8h.

10. The method for preparing an ultra-light self-cleaning microporous polyethylene spigot-and-socket type drainage pipe according to claim 8, characterized in that: The extrusion temperature of each layer in the three-layer co-extrusion extruder is set to: The extrusion temperature of the inner layer is 150-180°C, the extrusion temperature of the middle layer is 160-200°C, and the extrusion temperature of the outer layer is 180-210°C.

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