Hydrophobic and anti-scaling PVC (polyvinyl chloride) drainage pipe and preparation method thereof

Abstract

The invention relates to the technical field of PVC pipeline preparation, and particularly discloses a hydrophobic and anti-scaling PVC drainage pipe. Comprising the following raw materials in parts by mass: 100 parts of PVC resin, 8-10 parts of nano calcium, 3-5 parts of a calcium-zinc stabilizer, 0.8-1.5 parts of a lubricant, 1.2-2.0 parts of oxidized polyethlene wax, 8-12 parts of an impact modifier, 2-3 parts of an antioxidant, 5-7 parts of titanium dioxide, 3-5 parts of fluorinated silicon dioxide, 1-3 parts of a silane coupling agent, 4-6 parts of polyacrylate and 0.2-0.4 part of a whitening agent. The preparation method of the hydrophobic and anti-scale PVC drainage pipe comprises the following steps: S1, weighing the raw materials according to the raw material groups of the hydrophobic and anti-scale PVC drainage pipe in any one of claims 1-6; and S2, mixing and melting the raw materials weighed in the step S1, and carrying out extrusion molding through a screw extruder. The scheme is used for solving the problems that scale is easy to deposit and grease is easy to adhere in a common PVC drainage pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PVC pipe preparation, in particular to a hydrophobic and scale-resistant PVC drainage pipe and a preparation method thereof. BACKGROUND

[0002] When the traditional PVC-U drainage pipe is used in high-fat environments such as kitchens and catering, it generally has problems such as fat adhesion, scale deposition, and microbial growth. The surface energy of ordinary PVC pipe is relatively high, and water and oil stains are easy to stay on the pipe wall. After long-term accumulation, stubborn dirt is formed. In addition, kitchen wastewater often contains detergent, food residue and other components, making it easy for kitchen drainage pipes to scale, which seriously affects the drainage efficiency.

[0003] In the prior art, patent No. CN114889227B "Anti-scale PVC pipe and preparation method thereof" proposes to use UHMWPE ultra-high molecular weight polyethylene as an anti-scale layer to reduce dirt adhesion through its low friction properties. However, this scheme requires a double-layer co-extrusion process to combine the UHMWPE layer with the PVC substrate, which is complex and costly to process.

[0004] In addition, the prior art patent No. CN113861587A "Special pipe material for high-rise building rainwater discharge and its preparation method and application" optimizes the mechanical properties of PVC pipe material for high-rise building rainwater discharge scenarios by adding nano calcium carbonate and impact modifier to improve pressure resistance and impact resistance, but this technology does not involve hydrophobic or anti-scale design.

[0005] The prior art patent No. CN117362871A "High-impact-resistant weather-resistant pressure-bearing PVC pipe and its preparation method" uses ACR resin and organic silicon impact modifier to improve the toughness of the pipe material, and uses rutile titanium dioxide to improve the weather resistance. However, its surface still lacks effective hydrophobic structures and cannot solve the problem of easy oil adhesion.

[0006] In addition, the prior art also proposes chemical coating anti-scale technology, such as spraying polytetrafluoroethylene on the inner and outer surfaces of the pipe material. Although this can improve the surface performance in the short term, such coatings have poor adhesion to the PVC substrate and are prone to falling off under high-temperature extrusion or long-term water flow. In the production of PVC pipes, it is not possible to spray the inner wall of the pipe. More seriously, some coating materials may release harmful substances during processing, which does not meet environmental protection requirements.

[0007] In summary, the existing technology either focuses on single performance optimization and ignores the comprehensive needs of actual application scenarios, or is difficult to promote on a large scale due to complex processes or high costs. Therefore, there is an urgent need to develop a PVC drainage pipe that has excellent hydrophobicity, scale resistance, mechanical properties, and processing economy to meet the long-term use requirements of high-pollution environments such as kitchens. SUMMARY

[0008] The present application intends to provide a hydrophobic scale-preventing PVC drain pipe and a preparation method thereof to solve the problems of easy scale deposition and grease adhesion of common PVC drain pipes.

[0009] To achieve the above-mentioned purposes, the present application adopts the following technical solutions: The hydrophobic scale-preventing PVC drain pipe comprises the following raw material components by mass: 100 parts of PVC resin, 8-10 parts of nano calcium, 3-5 parts of calcium-zinc stabilizer, 0.8-1.5 parts of lubricant, 1.2-2.0 parts of oxidized polyethylene wax, 8-12 parts of impact modifier, 2-3 parts of antioxidant, 5-7 parts of titanium dioxide, 3-5 parts of fluorinated silicon dioxide, 1-3 parts of silane coupling agent, and 4-6 parts of polyacrylate.

[0010] Preferably, as an improvement, it further comprises 0.2-0.4 parts of whitening agent.

[0011] Preferably, as an improvement, the calcium carbonate content in the nano calcium is ≥97%, and the average particle size of the nano calcium is ≤100 nm.

[0012] Preferably, as an improvement, the titanium dioxide is nano titanium dioxide, and the particle size of the nano titanium dioxide is less than 50 nm.

[0013] Preferably, as an improvement, the particle size of the fluorinated silicon dioxide is not higher than 100 nm.

[0014] Preferably, as an improvement, the lubricant is monoglyceride.

[0015] Preferably, as an improvement, the impact modifier is ACR401. Preferably, as an improvement, the antioxidant is antioxidant 1010.

[0016] Preferably, as an improvement, the whitening agent is OB-01.

[0017] The present application further provides a preparation method of the hydrophobic scale-preventing PVC drain pipe, comprising the following steps: S1, weighing the raw materials of the hydrophobic scale-preventing PVC drain pipe; S2, mixing and melting the raw materials weighed in S1 and extruding them into a shape through a screw extruder.

[0018] Preferably, as an improvement, step S2 is specifically as follows: S21, mixing and stirring the PVC resin and calcium-zinc stabilizer; S22, adding the lubricant, impact modifier, and polyacrylate after being heated to 60℃ until they are uniformly stirred; S23, continue to warm up to 80℃, then add nano calcium, oxidized polyethylene wax, antioxidant, titanium dioxide, fluorinated silicon dioxide, silane coupling agent, mix until the temperature reaches 120-130℃; S24, cool the mixture to 40-45℃; S25, deliver the mixture obtained in S24 to a twin-screw extruder, plasticize and extrude at 180-210℃.

[0019] The principles and advantages of the present application are: 1. The present application uses PVC resin as the base material, combined with nano calcium, calcium-zinc stabilizer, oxidized polyethylene wax, fluorinated silicon dioxide, polyacrylate, etc., so that the tensile strength of the drainage pipe material reaches more than 41MPa, the elongation at break is not less than 120%, up to 150%, or even 170%. The water contact angle of the pipe surface is controlled at 87.8°-90.30°, so that the hydrophobicity of the pipe material is excellent compared with the current PVC pipe, which has a contact angle of only 50°-60°. In terms of oil stain prevention, the synergistic effect of the extremely low surface energy brought by fluorinated silicon dioxide and the surface structure of nanoscale raw materials makes the pipe material exhibit near super-oleophobic properties, with a contact angle of 148° for edible oil, which is close to the super-oleophobic property (usually considered to be >150° for super-oleophobicity), making it difficult for oil to adhere to the inner wall of the pipe, thereby greatly reducing the problem of scale deposition in the drainage pipe. It has been proven that in the 30-day accelerated scale deposition experiment, the calcium carbonate deposition amount is controlled at 0.1g / m 2 which is 85% lower than ordinary PVC pipes.

[0020] 2. The raw materials used in the present application include nano titanium dioxide and nano fluorinated silicon dioxide. The small size effect of nano particles enables them to be uniformly dispersed in the base material, making the compatibility of nano fluorinated silicon dioxide with other raw materials better, and helping to uniform plasticization. The introduction of silane coupling agent KH-570 further improves the interfacial bonding force between the nano particles and the base material, ensuring the stability of the material performance in long-term use, so that the inner surface roughness of the pipe material is reduced from 0.55-0.69µm of existing pipe materials to 0.14-0.19µm.

[0021] 3. Nano titanium dioxide not only has photocatalytic antibacterial function (the antibacterial test of the drainage pipe prepared by the present application shows that the antibacterial rate reaches more than 90%), but also can improve the weather resistance of the material. As a lubricant, oxidized polyethylene wax improves the processing performance while synergizing with polyacrylate to make the pipe surface gloss reach 67.8GU, making the roughness of the drainage pipe material lower and the appearance of the product more superior and attractive.

[0022] 4, The hydrophobic anti-fouling PVC drainage pipe is prepared by one-time extrusion molding process, and PVC resin and nano modified components are directly melt blended and extruded at a temperature of 180-210 DEG C. The process uses staged temperature control, first at a lower temperature to make the PVC matrix fully plasticized, and then gradually heated to ensure uniform dispersion of nano materials and other materials. Test data shows that the drainage pipe prepared by the process has stable surface hydrophobicity, the water contact angle fluctuation range is controlled within ±1 DEG, and the average difference of the elongation at break test result is also less than 6%. The one-time molding process avoids the secondary processing steps required by the traditional multi-layer composite pipe, and the prepared pipe shows good consistency in contact angle test data and anti-fouling performance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The stress-strain curve diagram in the tensile property test of the pipe obtained by formula three of the application.

[0024] Figure 2 The stress-strain curve diagram in the tensile property test of the pipe obtained by formula four of the application.

[0025] Figure 3 The stress-strain curve diagram in the tensile property test of the pipe obtained by formula five of the application. DETAILED DESCRIPTION

[0026] The following is further described in detail by specific embodiments: A hydrophobic anti-fouling PVC drainage pipe, comprising the following mass parts of raw material group: PVC resin 100 parts, nano calcium 8-10 parts, calcium zinc stabilizer 3-5 parts, lubricant 0.8-1.5 parts, oxidized polyethylene wax 1.2-2.0 parts, impact modifier 8-12 parts, antioxidant 2-3 parts, nano titanium dioxide 5-7 parts, fluorinated silicon dioxide 3-5 parts, silane coupling agent 1-3 parts, polyacrylate 4-6 parts, and whitening agent 0.2-0.4 parts.

[0027] The calcium carbonate content in the nano calcium is ≥97%, and the average particle size of the nano calcium is ≤100 nm.

[0028] The nano titanium dioxide has a particle size of 20-50 nm and is of rutile type, and the surface of the nano titanium dioxide can effectively hydrophobize, antibacterial, anti-pollution and self-cleaning.

[0029] The fluorinated silicon dioxide is a core-shell structure formed by substituting reaction of a fluorine-containing reagent with silicon hydroxyl (-Si-OH) on the surface of nano-silicon dioxide, bonding fluorine atoms to the surface of silicon dioxide to form a surface fluorination layer (-Si-F), thereby introducing a large number of fluorine atoms to the surface hydroxyl of silicon dioxide, so that the fluorinated silicon dioxide has surface hydrophobicity, surface active site and large specific surface area. The fluorinated silicon dioxide of the embodiment is a nanoparticle with a particle size of 50-100 nm, which can greatly improve the hydrophobicity, oil resistance and impact performance of the pipeline. The lubricant is monoglyceride, the impact modifier is ACR401, the antioxidant is antioxidant 1010, the whitening agent is OB-01, and the silane coupling agent is KH-570.

[0030] The preparation method of the hydrophobic and scale-resistant PVC drainage pipe comprises the following steps: Step 1: The raw materials of the hydrophobic and scale-resistant PVC drainage pipe are weighed according to the above-mentioned formula; Step 2: The PVC resin and calcium-zinc stabilizer are added to the mixer at low speed; Step 3: The lubricant, impact modifier and polyacrylate are added at high speed and 60°C; Step 4: The nano-calcium, oxidized polyethylene wax, antioxidant, whitening agent, nano-titanium dioxide, fluorinated silicon dioxide nanoparticles and silane coupling agent are continuously mixed at high speed and 80°C until the temperature reaches 120-130°C. The mixture is sent to the cooling machine for stirring, cooled to 40-45°C, and then the powder and the residue are separated through the vibrating screen. The separated material is transported to the storage tank; Step 5: The mixed material is transported to the double-screw extruder for plasticizing and extrusion, and then cooled and shaped. The processing temperature of the double-screw extruder is 170-210°C.

[0031] To verify the performance of the drainage pipe of the present application, the performance of the pipes prepared by different formulas using the same preparation method is compared. The specific formula table is shown in Table 1 below: Table 1 Formula Table

[0032] Note: The PVC resin used in the formula of the embodiment is SG-5 resin.

[0033] The performance indicators of the pipes prepared by the above different formulas using the same preparation method are shown in Table 2 below: Table 2 Test Performance Index Table

[0034] Note: The national standard GB / T 5836.1-2018 requires that the tensile strength of ordinary PVC-U drainage pipe material is ≥ 40 MPa, the longitudinal shrinkage rate is ≤ 5%, the Vicat softening temperature is ≥ 79℃, the elongation at break is ≥ 80, and the falling weight impact test is ≤ 10%.

[0035] From the case of formula one, the elongation at break is only 72%, although it has approached the requirements of the national standard for the elongation at break and tensile strength of ordinary PVC-U drainage pipe material, there is still a lot of room for improvement, and the surface L value of the pipe material is 88.32, the color is yellowish, the inner wall mold support pattern is obvious, and the inner wall roughness is 0.56µm, which is insufficient in flatness.

[0036] After adding nano titanium dioxide, fluorinated silicon dioxide, impact modifier, etc. to formula one, the tensile strength of formula two meets the national standard requirements, and the elongation at break reaches 95%, far exceeding the requirements of ordinary PVC drainage pipe, but the outer wall brightness L value is 89.17, the color is still yellowish, the inner wall roughness is 0.52µm, there is unevenness, and the flowability is also deviated.

[0037] By continuously adding polyacrylate and impact modifier to formula two, and adding calcium-zinc stabilizer, all the performances of formula three meet the requirements of the national standard for ordinary PVC drainage pipe, and the elongation at break is increased to an average of 117%. However, through multi-section testing of the pipe material of formula three, it is found that although the average elongation at break is 117%, the difference between the maximum elongation at break and the minimum elongation at break is large, the maximum elongation at break can reach about 157%, and the minimum elongation at break is only about 99%, the average difference is 16% (see Table 3, the tensile property test data table of 7 pipes produced by formula three), it can be seen that the consistency of the pipe material needs to be improved, and the product plasticization needs to be improved; in addition, from the stress-strain curve in Figure 1 It can be seen that after testing 7 drainage pipes under the same formula, the 7 drainage pipes show great differences in stress-strain, indicating that the quality consistency of the drainage pipe is not high. In addition, the outer wall brightness L value of the pipe material is 90.45, the visual smoothness of the outer surface is greatly improved compared with the previous one, the inner wall roughness is reduced to 0.31µm, which is much better than the 0.5µm roughness of ordinary PVC pipe on the market. Table 3 tensile property test data table of pipe material obtained by formula three

[0038] Formula four is based on the optimization of formula three, and fluorinated silicon dioxide and polyacrylate are added, and the oxidized polyethylene wax is slightly reduced. The performance indicators of the PVC pipe obtained by formula four all meet the requirements of the national standard, and the elongation at break is far beyond the standard value and reaches 152%, and the average difference of the elongation at break is also greatly reduced, and the average difference is reduced to 6% (see the tensile property test data table of 6 pipes produced in the same batch by formula four in Table 4 below), the outer wall brightness value is slightly lower than that of formula three, but the inner wall roughness is reduced to 0.19 µm, the outer surface finish is greatly improved, and the inner wall is also very smooth; in addition, the stress-strain curves of 6 PVC drainage pipes in the same batch of products are as follows Figure 2 It can be seen that the change of the 7 drainage pipes is basically the same, indicating that the product consistency is good.

[0039] Table 4 tensile property test data table of pipe material obtained by formula four

[0040] In order to make the scheme effect more beneficial, formula five is designed, the elongation at break of which is as high as 170%, and the average difference of the elongation at break is also less than 6% (see the tensile property test data table of 5 pipes produced in the same batch by formula five in Table 5 below), so that the PVC pipe obtained by this formula meets the requirements of high toughness product; in addition, the stress-strain curves of 5 PVC drainage pipes in the same batch of products are as follows Figure 3 It can be seen that the change of the 5 drainage pipes is basically the same, not only indicating that the product consistency is good, but also indicating that the strength is higher, the toughness is better, and the impact resistance is also higher than that of formula four.

[0041] Table 5 tensile property test data table of pipe material obtained by formula five

[0042] In addition, the outer wall brightness L value of the drainage pipe obtained by formula five is 93.47, the glossiness is 67.8 GU (tested according to GB / T9754-2007 at an incident angle of 60°), and the inner wall roughness is 0.14 µm; the pipe material of formula five is detected by GB / T30693-2014 “Plastic film and sheet water contact angle determination method”, and the detection results of 3 groups are as follows.

[0043] Table 6 contact angle detection results

[0044] It can be seen from Table 6 that the water contact angle of the pipe surface is controlled at 87.8°-90.30°, so that the hydrophobicity of the pipe material of the present application is very good compared with the corresponding contact angle of the current PVC pipe material, which is only 50°-60°.

[0045] In addition, the pipe prepared from the formula five is subjected to oil-repellent test, and the contact angle of edible oil reaches 148°, which is basically close to super oil-repellent property, so that it is difficult for oil to adhere to the inner wall of the pipe, thereby greatly reducing the problem of scale in the drain pipe. It has been verified that in the 30-day accelerated scale experiment, the calcium carbonate deposition amount is controlled to be 0.1 g / m 2 The following is reduced by 85% compared with the ordinary PVC pipe.

[0046] It can be seen that the present application improves the brightness of the inner and outer surfaces of the product by formula modification, plasma activation and fluorine-containing layer technology, realizes the super-hydrophobic, oil-repellent and long-acting scale prevention functions of the pipe surface. The method is simple in process and controllable in cost, can significantly improve the durability and environmental protection of the pipe under complex working conditions, and improve the impact performance, reduce or eliminate the brittle fracture problem of the product during packaging, transportation and construction.

[0047] The above-mentioned is only an embodiment of the present application, and the specific technical solutions and / or common knowledge of the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A hydrophobic scale resistant PVC drain pipe, characterized in that, The raw material group comprises: PVC resin 100 parts, nano calcium 8-10 parts, calcium-zinc stabilizer 3-5 parts, lubricant 0.8-1.5 parts, oxidized polyethylene wax 1.2-2.0 parts, impact modifier 8-12 parts, antioxidant 2-3 parts, titanium dioxide 5-7 parts, fluorinated silicon dioxide 3-5 parts, silane coupling agent 1-3 parts, and polyacrylate 4-6 parts.

2. A hydrophobic scale preventing PVC drain pipe according to claim 1, characterized in that: It also comprises whitening agent 0.2-0.4 parts.

3. A hydrophobic scale preventing PVC drain pipe according to claim 1, characterized in that: The calcium carbonate content in the nano calcium is ≥97%, and the average particle size of the nano calcium is ≤100 nm.

4. A hydrophobic scale preventing PVC drain pipe according to claim 1, characterized in that: The titanium dioxide is nano titanium dioxide, and the particle size of the nano titanium dioxide is less than 50 nm.

5. A hydrophobic scale preventing PVC drain pipe according to claim 1, characterized in that: The particle size of the fluorinated silicon dioxide is not higher than 100 nm.

6. A process for the preparation of a hydrophobic scale resistant PVC drain pipe, characterized in that, The method comprises the following steps: S1. Each raw material of the hydrophobic scale-preventing PVC drain pipe according to any one of claims 1-5 is weighed; S2. The weighed raw materials are mixed and fused, and then extruded into a shape by a screw extruder.

7. A process for the preparation of a hydrophobic scale preventing PVC drain according to claim 6, characterized in that: Step S2 is specifically as follows: S21. The PVC resin and the calcium-zinc stabilizer are mixed and stirred; S22. After being heated to 60℃, the lubricant, impact modifier, and polyacrylate are added, and stirring is continued until uniform; S23. After being continuously heated to 80℃, the nano calcium, oxidized polyethylene wax, antioxidant, titanium dioxide, fluorinated silicon dioxide, and silane coupling agent are added, and mixed until the temperature reaches 120-130℃; S24. The mixture is cooled to 40-45℃; S25. The mixture obtained in S24 is transported to a double-screw extruder, and plasticized and extruded into a shape at 180-210℃.

Images