CN113121932A

CN113121932A - PVC-U drainage pipe fitting and preparation method and application thereof

Info

Publication number: CN113121932A
Application number: CN202110322244.1A
Authority: CN
Inventors: 王绍雄; 徐政委; 余华林; 宋科明
Original assignee: Maoming Liansu Building Materials Co ltd
Current assignee: Maoming Liansu Building Materials Co ltd
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2021-07-16
Anticipated expiration: 2041-03-25
Also published as: CN113121932B

Abstract

The invention discloses a PVC-U drainage pipe fitting and a preparation method and application thereof.A component of an environment-friendly lead-free heat stabilizer, ultrafine nano active calcium carbonate and a composite high-efficiency environment-friendly nano inorganic antibacterial mildew-proof modifier is used for improving the performance of the PVC-U drainage pipe fitting, the pipe fitting is not easy to migrate, separate out and change color, the smoothness and brightness of the appearance of the pipe fitting are obviously improved, the flow resistance is small, and the PVC-U drainage pipe fitting has better wear-resistant and impact-resistant physical and mechanical properties; the pipe fitting has excellent hydrophobic property, smooth and flat surface, low interface free energy and difficult adhesion of carrier and silt, so that the pipe fitting has strong dirt resistance, small flow resistance, difficult scaling and color change and longer service life; the antibacterial and mildewproof effects are lasting, safe and efficient, the pipeline system is not easy to block, and the pollution of the mildews to water quality is avoided.

Description

PVC-U drainage pipe fitting and preparation method and application thereof

Technical Field

The invention relates to the technical field of drainage pipe fittings, in particular to a PVC-U drainage pipe fitting and a preparation method and application thereof.

Background

The PVC-U drainage pipe fitting has good mechanical property, corrosion resistance, electrical insulation property, low cost, light weight and easy processing, so the PVC-U drainage pipe fitting is widely applied to building houses, agriculture and municipal engineering, particularly the fields of civil building materials and municipal engineering drainage and sewage discharge, as the outdoor water quality contacted with the drainage and sewage discharge system is mostly rich in more organic matters and mineral matters, the mildew and algae substances are easy to breed in the water, particularly the key parts such as pipe fitting joints, the problems of pipe fitting physical property reduction, pipe fitting blockage, mildew and algae pollution, short service life and the like caused by the growth of the mildew and algae are solved, in addition, the pipe fitting product formula system is mostly rich in more plasticizers, monoglyceride, antioxidants and the like, the additives contain a large amount of grease and organic matters, although the appearance of the plastic pipe fitting is improved to a certain degree, The performance, but also aggravate the growth of bacteria, fungi and algae on the surface of the plastic pipe, the growth of flora algae is more active under the humid and illumination environment such as drainage and pollution discharge, and the like, which directly results in the problems of easy scaling and blockage of a pipeline system, and the like.

Chinese patent CN107828118A discloses an antibacterial wear-resistant plastic pipe and a preparation method thereof, wherein a silane coupling agent is used to couple the high-density polyethylene and the nano calcium carbonate interface, so as to improve the adhesion strength of the material, and the addition of nano silver can increase the antibacterial and mildewproof capabilities of the pipe. However, the adhesion method may cause the imbalance of the antibacterial and mildewproof capabilities of all parts of the surface of the pipe fitting, and the antibacterial and mildewproof durability of the pipe fitting which only depends on a small amount of nano silver is not strong, so that the adhesion of mildews cannot be fundamentally inhibited.

Disclosure of Invention

The invention aims to solve the technical problems that the existing PVC-U drainage and pollution discharge pipe fitting is not good enough in bacteriostasis and mildew-proof efficacy and easy to scale, and provides a PVC-U drainage pipe fitting which can realize high-efficiency bacteriostasis and mildew prevention in an open water quality environment and is not easy to scale on the surface of the pipe fitting.

The invention also aims to provide a preparation method of the PVC-U drainage pipe fitting.

The invention also aims to provide application of the PVC-U drainage pipe fitting.

The above purpose of the invention is realized by the following technical scheme:

a PVC-U drainage pipe fitting comprises the following components in parts by weight: 100 parts of PVC resin;

5-8 parts of an environment-friendly lead-free heat stabilizer;

10-30 parts of superfine nano active calcium carbonate;

1.5-3.5 parts of a processing aid ACR;

2.0-5.0 parts of an impact-resistant auxiliary agent;

1-3 parts of a functional lubricant;

2-5 parts of a composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier;

1-5 parts of pigment;

0.5-1.0 part of inorganic opacifier;

the PVC resin is loose resin prepared by a suspension polymerization method with the polymerization degree of 700-850 and the viscosity number of 73-86;

the superfine nano active calcium carbonate is functional inorganic filler treated by a surfactant; the particle size of the superfine nano active calcium carbonate is 25-100 nm;

the composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier is a compound of long-acting antibacterial material powder prepared by loading silver ions on biological carbon and inorganic nano zinc oxide mildew-proof material powder.

The PVC-U drainage pipe fitting provided by the invention takes PVC resin as a base material, and is added with components such as a composite efficient environment-friendly nano inorganic antibacterial and mildew-proof modifier, ultrafine nano active calcium carbonate and the like, wherein the ultrafine nano active calcium carbonate is a functional inorganic filler treated by a surfactant, and is characterized in that the surface is oleophylic and hydrophobic, the compatibility with resin is good, and the rigidity, toughness, smoothness and bending strength of the product can be effectively improved or adjusted; the processing performance is improved, the rheological property, the size stability and the heat-resisting stability of the product are improved, and the filling, reinforcing and toughening effects are realized, so that the glossiness and the smoothness of the pipe fitting can be greatly improved, the molecular energy of the inner surface and the outer surface of the pipe fitting and the interface free energy are reduced, and the hydrophobic performance is obviously improved; the composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier overcomes the characteristics of unstable carrier and uneven material dispersion in the injection molding process, so that the material can be uniformly dispersed in the injection molding process, the addition amount is low, the performance is stable, and processing defects such as precipitation, infusibility and the like can not occur; in addition, the spore enters cells through cell membranes of the spores to prevent the spores from sprouting or kill the spores, so that the pipe fitting has the characteristics of long-acting continuous bacteriostasis, mildew resistance, peculiar smell prevention, purification and the like; inorganic sunscreens also reflect sunlight, prevent light from penetrating the pipe, absorb ultraviolet light, and the like. The pigment is made of inorganic materials, and is not easy to migrate, separate out and change color, so that various properties of the product are more stable, and other formula components are green and environment-friendly, and have no potential harm to water quality, health and environment. The pipe fitting has stable physical performance, the pipeline system is not easy to block, and the pollution of mould to water quality and the like are avoided; the inner surface and the outer surface of the pipe fitting product are smooth and flat, and the pipe fitting product has excellent physical and mechanical properties, and in addition, the inner surface of the pipe fitting has excellent hydrophobic property, so that dirt and precipitates in water are extremely difficult to attach to the inner wall of the pipe fitting, the inner wall of the pipe fitting is prevented from scaling to form local blockage, and the flow rate is improved.

Preferably, the composition comprises the following components in parts by weight:

100 parts of PVC resin;

5.5-6.5 parts of an environment-friendly lead-free heat stabilizer;

15-25 parts of superfine nano active calcium carbonate;

1.8-3.0 parts of a processing aid ACR;

2.0-3.5 parts of an impact-resistant auxiliary agent;

1.5-2 parts of a functional lubricant;

3-5 parts of a composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier;

2-3 parts of a pigment;

0.5-1 part of inorganic light-screening agent.

Bulk resin prepared by suspension polymerization: dispersing vinyl chloride monomer in water containing suspension dispersant by mechanical stirring, initiating polymerization by a free radical initiator, stripping, removing residual monomer, and centrifugally drying to obtain the product.

Preferably, the polymerization degree of the PVC resin is 700-750; viscosity number is 70 to 81. The polymerization degree and the viscosity number of the PVC resin are limited in the interval, the resin powder characteristics of the suspension polymerization method at the injection molding level are met, the PVC resin is loose, has more pores, large surface area, easy absorption of plasticizer, stable resin molecular mass and distribution, good compatibility with other formula components, easy plasticization and excellent processability, and can be better fused with other components in the formula, so that the pipe fitting has excellent performance.

Preferably, the surfactant treatment is in Ca (OH)₂Introducing carbon dioxide gas into the suspension for carbonization, then adding a crystal form regulator, converting crystal nucleus formation control into crystal growth control, and then adding a dispersing agent to regulate particles to obtain uniformly dispersed cubic calcium carbonate nano particles; then the cubic nanometer calcium carbonate particles are processed by liquid phase surface coating treatment to obtain the superfine nanometer active calcium carbonate.

The surfactant treatment adopts Ca (OH) with certain concentration and purity₂Introducing high-purity carbon dioxide gas into the suspension to carry out carbonization. By reacting with Ca (OH)₂Controlling the nucleation rate of the calcium carbonate crystal nucleus by parameters such as the temperature, the pH value, the flow of carbon dioxide gas and the like of the suspension; after carbonization to form a certain number of crystal nuclei, the control of crystal nucleus formation is converted into the control of crystal growthDuring the preparation, a crystal form regulator is added to control the growth rate of each crystal face, so that the appearance is controllable; continuously carbonizing to the end point, adding a dispersing agent to adjust the surface charge of the particles to obtain uniformly dispersed cubic calcium carbonate nano particles; then the dispersed cubic nanometer calcium carbonate particles are subjected to liquid phase surface coating treatment to obtain the superfine nanometer active calcium carbonate.

Preferably, the crystal form regulator is one or more of phosphate, sulfate, acetate, citrate, monosaccharide or polysaccharide, and the addition amount of the crystal form regulator is 0.05-3.0% of the weight of the slurry.

Preferably, the coating agent used in the coating treatment is C12-C18 fatty acid, the addition amount is 0.5-3.5% by weight of calcium carbonate, the coating treatment time is 0.5-3.5 hours, and the slurry is filtered and dried to obtain the ultrafine nano active calcium carbonate.

Preferably, the mass ratio of the long-acting antibacterial material powder prepared by loading silver ions on biological carbon in the composite efficient environment-friendly nano inorganic antibacterial and mildewproof modifier to the inorganic nano zinc oxide mildewproof material powder is 2: 1.

Preferably, the processing aid ACR is a methyl methacrylate ACR.

Preferably, the impact resistance auxiliary agent is a methyl methacrylate-butadiene-styrene copolymer MBS impact resistance auxiliary agent.

Preferably, the environment-friendly lead-free heat stabilizer is a PVC calcium-zinc environment-friendly heat stabilizer compounded by taking zeolite, calcium-zinc-aluminum ternary hydrotalcite, dipentaerythritol ester and calcium stearate as main components.

Preferably, the functional lubricant is one or more of polyethylene wax, glyceryl monostearate and polyester plasticizer.

Preferably, the pigment is one or more of benzoxazole, titanium dioxide, cadmium red and azo pigment.

Preferably, the inorganic sunscreen agent is one or more of styrene/acrylic acid copolymer, carbon black and benzophenone.

The invention protects the preparation method of the PVC-U drainage pipe fitting, which comprises the following steps:

s1, mixing the raw materials according to the proportion, kneading and dispersing, cooling and stirring when the temperature reaches 110-120 ℃, and obtaining mixed materials for later use when the temperature is reduced to below 55 ℃;

s2, plasticizing the mixed material to be used in the step S1, extruding, granulating, pelletizing, cooling by a vibration tower, and packaging the pellets;

and S3, adding the granules extruded and granulated in the step S2 into a hopper of an injection molding machine, installing a corresponding injection mold of the drainage pipe fitting, and carrying out injection molding, pressure maintaining, cooling, mold supporting, trimming and packaging.

Preferably, the kneading dispersion of step S1 is performed in a high-speed hot mixer.

Preferably, the plasticizing of step S1 is performed in a twin screw extruder.

Preferably, the double-screw extruder is a counter-rotating parallel double-screw extruder, the temperature of a machine barrel is set to be 140-170 ℃, the temperature of a die head is set to be 150-170 ℃, and the vacuum degree is more than or equal to 0.06 MPa.

Preferably, the injection molding temperature is set to be 165-185 ℃, and the mold cooling temperature is 25-30 ℃.

The invention also protects the application of the PVC-U drainage pipe fitting in the fields of building home, agriculture or municipal engineering.

Compared with the prior art, the invention has the beneficial effects that:

the invention improves the performance of the pipe fitting by improving the components, wherein the pigment is made of inorganic materials and is not easy to migrate, separate out and change color, so that various performances of the product are more stable, and other formula components are green and environment-friendly, have no potential harm to water quality, health and environment, and have good market prospect; the auxiliary agent can be fully and uniformly combined with the resin and the superfine nano activated calcium carbonate to form a coating body between molecules so that the grafting of the auxiliary agent molecules and the combination of active groups and the resin are firmer, the bacteriostatic and mildewproof capabilities of all parts on the surface of the pipe fitting are balanced, and the compound auxiliary agent can be prevented from being separated out from the resin and migrating in the process of using the environment so that the bacteriostatic and mildewproof durability is better; the composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier is characterized in that long-acting antibacterial material powder prepared by loading silver ions on biological carbon and inorganic nano zinc oxide mildew-proof material powder are combined to achieve the effect that one is added and the other is more than two, the defects that a carrier is unstable and the material is dispersed unevenly in the injection molding process are overcome, the material can be dispersed evenly in the injection molding process, and the processing defects of precipitation, infusibility and the like cannot occur; the inorganic light-shading agent can effectively block light from penetrating, shield light, block air, prevent the aging of the plastic pipeline, reduce the light transmittance of the pipe fitting and weaken the growth conditions of mould, algae and the like in the pipe fitting. The pipe surface interface has extremely low free energy and high smoothness, so that carriers and silt on the surface of the pipe are difficult to attach, thus mould and algae can not form local mould scale, the breeding of the mould is indirectly prevented, and the pollution of the mould to water quality is avoided. The flow resistance is small, scaling and color change are not easy to occur, the physical performance of the pipe fitting is stable, the pipeline system is not easy to block, and the service life is longer.

The preparation method provided by the invention adopts the specific components to carry out extrusion granulation and injection molding after compounding, can be produced by utilizing the existing pipe fitting mold and can be realized on the basis of the prior art, and meanwhile, inorganic colored sand can be added into a formula system for coloring, so that the use requirements of different environments and fields are met, and the size of a runner, the wall thickness of a main body, an electroplated layer on the surface of a cavity and a chamfer angle of the cavity of the pipe fitting mold can be properly changed; the specification including straight-through, elbow, tee joint and the like can be prepared, and the injection molding process and flow can be partially improved.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.

Materials used in the following examples and comparative examples:

PVC resin: the polymerization degree is 700, the viscosity number is 79, and the loose resin is prepared by a suspension polymerization method.

The environment-friendly lead-free heat stabilizer comprises the following components: the PVC calcium-zinc environment-friendly heat stabilizer is compounded by using zeolite, calcium-zinc-aluminum ternary hydrotalcite, dipentaerythritol ester and calcium stearate as main components.

Superfine nano active calcium carbonate: surface treatment is carried out on the particle size of 95 nm: the surfactant treatment adopts Ca (OH) with certain concentration and purity₂Introducing high-purity carbon dioxide gas into the suspension to carry out carbonization. By reacting with Ca (OH)₂Controlling the nucleation rate of the calcium carbonate crystal nucleus by parameters such as the temperature, the pH value, the flow of carbon dioxide gas and the like of the suspension; after the carbonization is carried out until a certain number of crystal nuclei are formed, the crystal nucleus formation control is converted into crystal growth control, and at the moment, a crystal form regulator is added to control the growth rate of each crystal face, so that the controllable appearance is achieved; continuously carbonizing to the end point, adding a dispersing agent to adjust the surface charge of the particles to obtain uniformly dispersed cubic calcium carbonate nano particles; then carrying out liquid phase surface coating treatment on the evenly dispersed cubic nano calcium carbonate particles to obtain the superfine nano active calcium carbonate.

Processing aid ACR: methyl methacrylate.

Impact resistance auxiliary agent MBS: methyl methacrylate-butadiene-styrene copolymer.

Functional lubricant: polyethylene wax and polyester plasticizer.

The composite efficient environment-friendly nano inorganic antibacterial mildew-proof modifier comprises the following components: the long-acting antibacterial material powder prepared by the biological carbon loaded with silver ions and the inorganic nano zinc oxide mildew-proof material powder.

Pigment: benzoxazole toner and titanium dioxide.

Inorganic light-screening agent: styrene/acrylic acid copolymer.

Examples 1-2 and comparative example 1

A PVC-U drainage pipe member comprising the components in parts by weight as shown in table 1 below.

TABLE 1 composition and parts by weight of PVC-U drainpipe member of each example and comparative example

The preparation method of the PVC-U drainage pipe fitting comprises the following steps:

s1, mixing the raw material components, adding the raw material components into a high-speed hot mixer for high-temperature high-speed kneading and dispersing, transferring the mixture into a cold mixer for low-speed stirring and cooling when the temperature reaches 115 ℃, and discharging the mixture into a hopper for later use when the temperature is reduced to below 55 ℃;

s2, adding the mixed ingredients to be used in the hopper of S1 into a double-screw extruder for plasticizing, extruding and granulating, pelletizing, cooling by a vibration tower, and packaging the pellets; the double-screw extruder is a counter-rotating parallel double-screw extruder, the temperature of the machine barrel is set to 170 ℃ in a machine barrel 1 region, 165 ℃ in a second region, 160 ℃ in a third region, 155 ℃ in a fourth region, 150 ℃ in a fifth region and 145 ℃ in a 6 region, the temperature of the die head is set to 160 ℃ in a die head 1 region, 165 ℃ in the second region, and the vacuum degree is more than or equal to 0.06 MPa;

s3, adding the extruded and granulated granules obtained in the step S2 into a hopper of an injection molding machine, installing a corresponding injection mold of the drainage pipe fitting, performing injection molding, maintaining pressure, cooling, supporting the mold, trimming and packaging; wherein the molding temperature of the injection molding machine is set to be 185 ℃, 180 ℃ at the first section, 175 ℃ at the second section, 170 ℃ at the third section, 165 ℃ at the fourth section and 160 ℃ at the fifth section, and the cooling temperature of the mold is 25 ℃.

Performance testing

1. Test method

Following relevant standards, regimes: the national standard GB/T5836.2-2018 rigid polyvinyl chloride PVC-U pipe fitting for building drainage; the pipe fitting needs to meet the requirements that the light transmittance is less than or equal to 0.2 percent and the bacteriostatic rate is greater than or equal to 99.0 percent.

2. And (3) testing results: product specification dn75 straight-through

TABLE 2 test results of examples and comparative examples

Item

Baking oven

Falling down

Vicat

Density of

Limit of lead

Light transmittance

Rate of inhibition of bacteria

Example 1

Qualified

79.3

1451

4.5ppm

4.2％

88.3％

Example 2

Qualified

79.6

1451

4.9ppm

0.05％

99.5％

Example 3

Qualified

79.7

1451

5.1ppm

2.1％

92.6％

Example 4

Qualified

79.5

1451

5.0ppm

0.1％

95.7％

Comparative example 1

With a layer separation

Qualified

77.5

1451

4.7ppm

10.5％

5.4％

Comparative example 2

Qualified

79.2

1451

4.6ppm

0.05％

19.5％

Comparative example 3

Qualified

79.5

1451

5.3ppm

10.5％

85.2％

The surface smoothness can be measured by extruding the formula material through an extruder to prepare samples and measuring the surface friction coefficient contrast. The PVC-U pipe fittings of the embodiments 1-4 have extremely high surface smoothness, good pipe fitting plasticization and inhibition of adhesion of mold; comparative examples 1 to 3 had rough surfaces and poor smoothness.

The test results in table 2 show that the physical properties of the product can reach the standard by adding the ultrafine nano activated calcium carbonate, and the light transmittance and the bacteriostasis rate are adjusted along with the increase of the opacifier and the composite bacteriostatic and mildewproof agent, so that the light transmittance is gradually reduced, and the bacteriostasis rate is gradually increased; in the comparative example, one of the three variables is lacked, the performance of the pipe fitting is defective, the plasticizing effect is common when superfine nano calcium is not used, the performance of the oven is layered, the single opacifier can only slow down the growth of flora when the composite bacteriostatic mildew inhibitor is not used, the composite bacteriostatic mildew inhibitor which is only used without opacifier cannot fully play a role, and the growth of flora is accelerated by illumination.

The wettability and hydrophobicity of the surface of the pipe and the water carrier are generally evaluated by the contact angle between the surface and the water carrier. The contact angle is formed by the included angle between the tangent and the solid-liquid interface at the solid-liquid contact point along the tangent of the liquid-phase interface. If the solid surface is smooth, the shape of the water drop on the surface is determined by the interfacial tension of the solid-liquid-gas three-phase contact surface. The contact angle equal to 90 ° is the critical angle to determine whether water is hydrophilic with a solid surface. If the contact angle is greater than 90 °, the solid is hydrophobic, otherwise it is hydrophilic; surfaces with contact angles greater than 150 ° are referred to as superhydrophobic surfaces. In general, the larger the contact angle, the more hydrophobic the surface. The method can be measured by an optical water drop angle measuring instrument, wherein the method comprises the following steps of 1-4: contact angle 115 °; indicating that the pipe surface is a hydrophobic surface. Comparative example 1: contact angle 75 °; the surface of the pipe element is a hydrophilic surface. Comparative examples 2, 3: contact angle 109 °; the surface of the pipe belongs to a hydrophobic surface, but the hydrophobic performance is not as good as that of the pipe in the embodiments 1-4, the pipe manufactured by the invention has extremely high smoothness, the surface of the pipe has a micro-nano structure, the surface energy and the interface free energy of the pipe are low, the hydrophobic performance is obviously improved, the excellent hydrophobic performance ensures that dirt and sediment in water are extremely difficult to attach to the inner wall of the pipe, the scaling of the inner wall of the pipe is avoided to form local blockage, and the flow rate is improved.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A PVC-U drainage pipe fitting is characterized by comprising the following components in parts by weight:

100 parts of PVC resin;

5-8 parts of an environment-friendly lead-free heat stabilizer;

10-30 parts of superfine nano active calcium carbonate;

1.5-3.5 parts of a processing aid ACR;

2.0-5.0 parts of an impact-resistant auxiliary agent;

1-3 parts of a functional lubricant;

1-5 parts of pigment;

0.5-1.0 part of inorganic opacifier;

2. The PVC-U drain pipe member according to claim 1, comprising the following components in parts by weight:

100 parts of PVC resin;

5.5-6.5 parts of an environment-friendly lead-free heat stabilizer;

15-25 parts of superfine nano active calcium carbonate;

1.8-3.0 parts of a processing aid ACR;

2.0-3.5 parts of an impact-resistant auxiliary agent;

1.5-2 parts of a functional lubricant;

2-3 parts of a pigment;

0.5-1 part of inorganic light-screening agent.

3. The PVC-U drainage pipe fitting according to claim 1 or 2, wherein the polymerization degree of the PVC resin is 700-750; viscosity number is 70 to 81.

4. The PVC-U drainage tube of claim 1, wherein the surfactant treatment is in Ca (OH)₂Introducing carbon dioxide gas into the suspension to carry out carbon preparationAfter the crystallization, adding a crystal form regulator, converting crystal nucleus formation control into crystal growth control, and then adding a dispersing agent to regulate particles to obtain uniformly dispersed cubic calcium carbonate nano particles; then the cubic nanometer calcium carbonate particles are processed by liquid phase surface coating treatment to obtain the superfine nanometer active calcium carbonate.

5. The PVC-U drainage pipe fitting of claim 1, wherein the mass ratio of the long-acting antibacterial material powder prepared by loading silver ions on biological carbon in the composite efficient environment-friendly nano inorganic antibacterial and mildewproof modifier to the inorganic nano zinc oxide mildewproof material powder is 2: 1.

6. The PVC-U drainage pipe of claim 1 or 2, wherein the impact resistance aid is a methyl methacrylate-butadiene-styrene copolymer MBS impact resistance aid.

7. The PVC-U drainage pipe fitting of claim 1, wherein the environment-friendly lead-free heat stabilizer is a PVC calcium zinc environment-friendly heat stabilizer compounded by taking zeolite, calcium zinc aluminum ternary hydrotalcite, dipentaerythritol ester and calcium stearate as main components.

8. The PVC-U drain pipe fitting according to claim 1, wherein said functional lubricant is one or more of polyethylene wax, glyceryl monostearate, polyester plasticizer.

9. The method for preparing the PVC-U drainage pipe fitting of any one of claims 1 to 8, which is characterized by comprising the following steps:

10. Use of the PVC-U drainage pipe fitting of any one of claims 1 to 8 in the field of building home, agriculture or municipal engineering.