A fluoropolymer modified PVC pipe material and its preparation method and application

Abstract

The present invention discloses a fluoropolymer modified PVC material and a preparation method and application thereof, and relates to the technical field of polymer materials. The fluoropolymer modified PVC material of the present invention comprises polyvinyl chloride resin, fluoropolymer modifier, compatibilizer, filler, heat stabilizer, titanium dioxide, and processing aid, wherein the melting point of the fluoropolymer modifier is within the processing temperature range of the PVC material, and the compatibilizer is chlorinated polyethylene and / or polymethyl methacrylate, wherein the mass of the compatibilizer accounts for 3 to 8% of the mass of the polyvinyl chloride resin; and the mass ratio of the fluoropolymer modifier to the compatibilizer is 2.4 to 3:1. The fluoropolymer modified PVC material of the present invention improves the compatibility of the fluoropolymer modifier with the PVC material system through the addition of a specific compatibilizer, and the synergistic effect of each component reduces the performance loss of the main body of the material, realizes the interface regulation of the PVC resin matrix and the fluoropolymer modifier, thereby further improving the hydrophobicity and mechanical properties of the PVC pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically to a fluoropolymer modified PVC pipe material and a preparation method and application thereof. Background Art

[0002] PVC pipe products are made of polyvinyl chloride resin as raw material, and inorganic fillers, heat stabilizers, impact modifiers, and processing aids are added to the physical blending to achieve PVC pipe extrusion injection molding. They are often widely used in building water supply and drainage and municipal water supply and drainage. With the continuous expansion of PVC application areas, PVC pipes are increasingly used in agricultural water and fertilizer integrated supply and material distribution in the chemical food industry. At the same time, new requirements are also put forward for the performance of PVC pipe products. For example, on the basis of traditional impact resistance, pressure resistance, and corrosion resistance, PVC pipe products are also required to have the characteristics of hydrophobicity and oleophobicity, and at the same time, they can reduce pipeline transportation resistance, achieve self-cleaning effect, and improve transportation efficiency.

[0003] The prior art discloses a super-hydrophobic pipe and a preparation method thereof, which improves the hydrophobicity of the PVC pipe by introducing a powdered polytetrafluoroethylene composite material into PVC, thereby increasing the service life of the pipe, and increases the crosslinking degree of the polytetrafluoroethylene composite material by using N-heptafluorobutyrylimidazole and 1,7-dibromoheptane, thereby increasing its strength. However, the processing temperature of PVC pipes is generally 160-210°C, and the melting point of polytetrafluoroethylene is above 300°C, so when processed into PVC pipes, it will exist as solid particles and cannot be compatible with PVC resin and other raw materials, thereby affecting the mechanical properties of PVC materials. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects and shortcomings of the existing hydrophobic modified PVC material using polytetrafluoroethylene, such as poor compatibility between the hydrophobic modified component and PVC, which leads to poor mechanical properties, and to provide a fluoropolymer modified PVC material, which improves the overall compatibility through the synergistic effect between specific components, achieves a hydrophobic effect and has good mechanical properties, especially impact resistance.

[0005] Another object of the present invention is to provide a method for preparing a fluoropolymer modified PVC material.

[0006] Another object of the present invention is to provide an application of a fluoropolymer modified PVC material in the preparation of a PVC pipe.

[0007] Another object of the present invention is to provide a PVC pipe.

[0008] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0009] A fluoropolymer modified PVC material, comprising the following components:

[0010] Polyvinyl chloride resin, fluoropolymer modifier, compatibilizer, filler, heat stabilizer, titanium dioxide, processing aid, other additives,

[0011] The compatibilizer is chlorinated polyethylene and / or polymethyl methacrylate,

[0012] The melting point of the fluoropolymer modifier is within the processing temperature range of the PVC material.

[0013] Wherein, the mass of the compatibilizer accounts for 3-8% of the mass of the polyvinyl chloride resin;

[0014] The mass ratio of the fluoropolymer modifier to the compatibilizer is 2.4 to 3:1.

[0015] Fluoropolymer modifiers contain a large number of fluorine atoms, which have strong polarity. When fluorine atoms combine with other elements, they can capture their electrons and form a stable structure with 8 electrons in the outermost layer. Therefore, it is difficult for other groups to have van der Waals forces with fluorine atoms. Therefore, fluoropolymer modifiers have low surface energy and have good hydrophobic modification effects.

[0016] Compared with general fluoropolymer hydrophobic modifiers, the melting point of the fluoropolymer modifier of the present invention is within the processing temperature range of the PVC material, and can be fully melted into one with the PVC material during the processing process. Moreover, by adding a specific compatibilizer, the specific solubility parameter thereof is utilized to achieve a volume expansion effect, and intermolecular forces are generated with the PVC resin and the fluoropolymer, thereby improving the compatibility of the modified system, reducing the performance loss of the main body of the material, and realizing the interface regulation between the PVC resin matrix and the fluoropolymer modifier, thereby further improving the hydrophobicity and impact resistance of the PVC pipe.

[0017] In addition, the compatibilizers of the present invention such as chlorinated polyethylene and polymethyl methacrylate themselves have an impact-modifying effect and can further improve the mechanical properties of PVC materials.

[0018] The compatibilizer of the present invention can help improve the compatibility of PVC resin and fluoropolymer, and the specific working principle is as follows:

[0019] 1. Hydrogen bonds can be formed between polymethyl methacrylate (PMMA) and PVC molecules, while PMMA and PVDF copolymers can use their strong polar structure to form dipole-dipole forces to improve compatibility.

[0020] 2. Chlorinated polyethylene CPE has a similar structure to PVC materials, with chlorine atoms replacing H on CC bonds. It has good compatibility and a solubility parameter lower than that of PVDF copolymers. However, the selection of high chlorine content increases the cohesive energy density, thereby improving its solubility parameter, adapting to PVDF copolymers, and improving system compatibility.

[0021] The compatibilizer of the present invention is preferably chlorinated polyethylene with a chlorine content of 40%, while the chlorinated polyethylene generally used as an impact modifier has a chlorine content of 35%.

[0022] The filler of the present invention can be a filler conventionally added to PVC, such as SiO2, talcum powder, etc., preferably with an average particle size of 1-10 μm, and surface activation treatment is performed. The content of the filler can be a conventional content, such as 3-7% of the mass of the polyvinyl chloride resin.

[0023] The heat stabilizer of the present invention can be a heat stabilizer conventionally added to PVC, such as a lead salt stabilizer, an organic tin stabilizer, a hydrotalcite heat stabilizer, a metal soap heat stabilizer, and a rare earth stabilizer, etc., preferably a metal soap heat stabilizer, such as a calcium zinc stabilizer, which is more non-toxic and environmentally friendly and more suitable for pipes in agriculture and the food industry. The content of the heat stabilizer can be a conventional content, such as 3 to 5% of the mass of the polyvinyl chloride resin.

[0024] In a specific embodiment, the mass ratio of the compatibilizer of the present invention to the total mass of the fluoropolymer-modified PVC material can be, for example, 3%, 4%, 5%, 6%, 7%, 8%, etc.

[0025] Preferably, the fluoropolymer modifier is one or both of polyvinylidene fluoride-chlorotrifluoroethylene copolymer and polyvinylidene fluoride-hexafluoropropylene copolymer.

[0026] By copolymerizing polyvinylidene fluoride with chlorotrifluoroethylene or hexafluoropropylene having a high fluorine content, chlorine atoms or side groups can be introduced into the main chain of the copolymer, so that it has both the impact resistance of polyvinylidene fluoride and the hydrophobicity brought by the high fluorine content.

[0027] In order to further control the proportion of the rubber state in the fluoropolymer modifier and optimize the mechanical properties of the PVC material, preferably, the ratio of the comonomers vinylidene fluoride and chlorotrifluoroethylene in the polyvinylidene fluoride-chlorotrifluoroethylene copolymer is 1:1 to 1.5.

[0028] The polyvinylidene fluoride-hexafluoropropylene copolymer is equivalent to introducing hexafluoropropylene units into polyvinylidene fluoride, which has greater steric hindrance, can hinder the orderly arrangement of vinylidene fluoride chain segments, reduce the crystallinity of the material, make the material more flexible, improve the impact performance of the material, and at the same time, the high fluorine content shows strong hydrophobicity. In the specific implementation process, preferably, the ratio of comonomers vinylidene fluoride (VDF) and hexafluoropropylene (HFP) in the polyvinylidene fluoride-hexafluoropropylene copolymer is 8 to 12:1, and the melting point of the material is about 140°C.

[0029] Preferably, the average particle size of the fluoropolymer modifier is ≤15 μm. A particle size below 15 μm can achieve a good dispersion effect, reduce interface defects, and alleviate performance loss caused by the introduction of hydrophobic groups.

[0030] In a specific embodiment, the particle size of the fluoropolymer modifier is 1 to 15 μm.

[0031] Preferably, the other additives include PE wax, paraffin wax, and pigments. The total content of the other additives may be a conventional content, for example, 0.5 to 1.5% of the mass of the polyvinyl chloride resin.

[0032] Preferably, the other additives include 0.2-0.6% of PE wax, 0.2-0.6% of paraffin wax, and 0.05-0.1% of masterbatch calculated by mass percentage of polyvinyl chloride resin.

[0033] The fluoropolymer modified PVC material of the present invention comprises the following components in parts by mass:

[0034] 100 parts of polyvinyl chloride resin, 7-25 parts of fluoropolymer modifier, 3-8 parts of compatibilizer, 3-7 parts of filler, 3-5 parts of heat stabilizer, 2-5 parts of titanium dioxide, 0.2-0.8 parts of processing aid, and 0.5-1.5 parts of other additives.

[0035] In the fluoropolymer modified PVC pipe material of the present invention, titanium dioxide and color masterbatch are mainly used for adjusting the product color; processing aids and paraffin wax and PE wax are used for improving the plasticization and molding processing of PVC.

[0036] The present invention also protects a method for preparing a fluoropolymer modified PVC material, which comprises the following steps:

[0037] Add polyvinyl chloride resin and heat stabilizer and stir evenly. When the temperature rises to 80-120°C, add compatibilizer, fluoropolymer modifier and remaining components in sequence, stir well and cool to obtain fluoropolymer modified PVC material.

[0038] The use of a fluoropolymer modified PVC material in the preparation of PVC pipes is also within the protection scope of the present invention.

[0039] The present invention also specifically protects a PVC pipe prepared from the above fluoropolymer-modified PVC material.

[0040] The beneficial effects of the present invention are:

[0041] The fluoropolymer modified PVC material of the present invention improves the compatibility of the fluoropolymer modifier and the PVC material system through the synergistic effect of various components by adding a specific compatibilizer, reduces the performance loss of the material body, and realizes the interface regulation between the PVC resin matrix and the fluoropolymer modifier, thereby further improving the hydrophobicity and mechanical properties of the PVC pipe.

[0042] The PVC pipe prepared by the fluoropolymer modified PVC material of the present invention has no cracks or leakage in a hydrostatic test at 20°C and 40MPa for 1h, and the cantilever beam notched impact strength is ≥3.9KJ / m 2 , water contact angle contact angle>120°. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0044] The main materials of the embodiments and comparative examples are described as follows:

[0045] Polyvinyl chloride resin: China Thai Chemical Co., Ltd., SG5;

[0046] Fluoropolymer modifier:

[0047] Polyvinylidene fluoride-chlorotrifluoroethylene copolymer (PVDF-CTFE): Shanghai Huayi Sanaifu New Materials Co., Ltd., the molar ratio of comonomer VDF: CTFE is 1:1;

[0048] Polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP): Shanghai Huayi Sanaifu New Materials Co., Ltd., the molar ratio of monomer content VDF:HFP is 8 to 12:1;

[0049] Polytetrafluoroethylene (PTFE): Shanghai Huayi Sanaifu New Materials Co., Ltd., suspension polymer resin

[0050] Compatibilizer:

[0051] Chlorinated polyethylene: Weifang Yaxing Chemical Co., Ltd., chlorine content 40%, CPE140B;

[0052] Polymethyl methacrylate; Zhenjiang Chimei Chemical Co., Ltd., CM-205;

[0053] Methyl methacrylate, butadiene and styrene copolymer (MBS): Shandong Ruifeng, LB-564

[0054] filler:

[0055] Calcium carbonate: Jiangmen Huixiong Non-metallic Materials Co., Ltd., BT-2;

[0056] Heat Stabilizer:

[0057] Calcium zinc stabilizer: Baerlocher Plastic Additives (Jiangsu) Co., Ltd., R161FP;

[0058] Titanium dioxide: Nanjing Titanium Dioxide Chemical Co., Ltd., NR950;

[0059] Processing aid: Shandong Riko Chemical Co., Ltd., LPA-40.

[0060] Embodiments 1 to 5

[0061] A fluoropolymer modified PVC material includes components and contents as shown in Table 1 in parts by weight.

[0062] Table 1

[0063] raw material 1 2 3 4 5 Polyvinyl chloride resin 100 100 100 100 100 PVDF-CTFE 24 15 8 15 PVDF-HFP / / / 15 CPE 8 5 3 5 PMMA / / / 5 Calcium carbonate 5 5 5 5 5 Calcium zinc stabilizer 4 4 4 4 4 Titanium dioxide 3 3 3 3 3 Processing Aids 0.5 0.5 0.5 0.5 0.5 Other additives 1 1 1 1 1

[0064] Other additives are: PE wax 0.5%, paraffin wax 0.5%, masterbatch 0.1%.

[0065] The fluoropolymer modified PVC pipe material is processed according to the components of Examples 1 to 5 in Table 1, specifically comprising the following steps:

[0066] S1. Add polyvinyl chloride resin and calcium zinc stabilizer to the container under stirring in a hot mixing tank, start high-speed stirring, and when the temperature rises to 80°C, add a compatibilizer, a fluoropolymer modifier and the remaining components in sequence;

[0067] S2. Continue to raise the temperature to 120°C, add calcium carbonate and titanium dioxide, stir thoroughly, discharge into a cold mixing tank and cool to 40°C to obtain a fluoropolymer modified PVC material.

[0068] The fluoropolymer-modified PVC material was used to prepare a PVC pipe with an outer diameter of 110 mm and a wall thickness of 6.6 mm.

[0069] Comparative Examples 1 to 7

[0070] A fluoropolymer modified PVC material includes components and contents as shown in Table 2 in parts by weight.

[0071] Table 2

[0072]

[0073] Other additives are: PE wax 0.5%, paraffin wax 0.5%, masterbatch 0.1%.

[0074] The fluoropolymer modified PVC pipe materials of Comparative Examples 1 to 7 are obtained by processing according to the components in Table 2, and their preparation methods are the same as those in Example 1.

[0075] Performance Testing

[0076] According to GB / T 4219.1-2008 "Industrial rigid polyvinyl chloride (PVC-U) piping system Part 1: Pipes", the fluoropolymer modified PVC pipes prepared in Examples 1-5 and Comparative Examples 1-7 were tested, and the results are shown in Tables 3 and 4:

[0077] Table 3

[0078]

[0079]

[0080] Table 4

[0081]

[0082] From the data in Table 3 above, it can be seen that the fluoropolymer modified PVC material of the present invention improves the compatibility of the fluoropolymer modifier and the PVC material system through the addition of a specific compatibilizer, and the synergistic effect of each component improves the compatibility of the fluoropolymer modifier and the PVC material system. The prepared PVC pipe has good hydrophobicity and mechanical properties. The hydrostatic performance test results show that there is no crack or leakage at 20°C and 40MPa for 1h, and the cantilever beam notched impact strength can reach 4.1KJ / m 2 And above, the water contact angle of the pipe is also above 120°C, with good hydrophobic properties.

[0083] In Comparative Example 3, polytetrafluoroethylene is used to replace the fluoropolymer modifier of the present invention. The melting point is not within the processing temperature range of the PVC material. When processed into PVC pipes, it will exist as solid particles and is incompatible with PVC resin and other raw materials. Although it also has certain hydrophobic properties, the mechanical properties are significantly affected. The hydrostatic performance breaks at 0.39h, and the cantilever beam notch impact strength is only 2.6KJ / m 2 .

[0084] The compatibilizer used in Comparative Example 4 is methyl methacrylate, butadiene and styrene copolymer (MBS), which is not the specific compatibilizer protected by the present invention. Obviously, it cannot achieve the corresponding volume expansion effect, and cannot enhance the intermolecular force with PVC resin and fluoropolymer, thereby affecting the compatibility of the modified system, and the mechanical properties are obviously affected. The hydrostatic performance breaks at 0.74h, and the cantilever beam notched impact strength is only 3.2KJ / m 2 .

[0085] The mass ratio of the fluoropolymer modifier to the compatibilizer in Comparative Examples 5 and 6 is not within the protection scope of the present invention and cannot achieve a good synergistic effect, and the overall hydrophobicity and mechanical properties cannot achieve the balanced effect of the present invention.

[0086] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A fluoropolymer modified PVC material, characterized in that: In parts by weight, it includes the following components: Polyvinyl chloride resin, fluoropolymer modifier, compatibilizer, filler, heat stabilizer, titanium dioxide, processing aid, other additives, The melting point of the fluoropolymer modifier is within the processing temperature range of the PVC material. The compatibilizer is chlorinated polyethylene and / or polymethyl methacrylate, Wherein, the mass of the compatibilizer accounts for 3-8% of the mass of the polyvinyl chloride resin; The mass ratio of the fluoropolymer modifier to the compatibilizer is 2.4 to 3:

1. The fluoropolymer modifier is a polyvinylidene fluoride-chlorotrifluoroethylene copolymer or a polyvinylidene fluoride-hexafluoropropylene copolymer. When the fluoropolymer modifier is polyvinylidene fluoride-hexafluoropropylene copolymer, the molar ratio of the copolymer monomers vinylidene fluoride and hexafluoropropylene is 8 to 12:1; When the fluoropolymer modifier is polyvinylidene fluoride-chlorotrifluoroethylene copolymer, the molar ratio of the copolymer monomers vinylidene fluoride and chlorotrifluoroethylene is 1:1-1.

5.

2. The fluoropolymer modified PVC material according to claim 1, characterized in that: The particle size of the fluoropolymer modifier is ≤15 μm.

3. The fluoropolymer modified PVC material according to claim 2, characterized in that: The particle size of the fluoropolymer modifier is 1 to 15 μm.

4. The fluoropolymer modified PVC material according to any one of claims 1 to 3, characterized in that: The other additives include PE wax, paraffin and pigment.

5. A method for preparing the fluoropolymer modified PVC material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Add polyvinyl chloride resin and heat stabilizer and stir evenly. When the temperature rises to 80-120°C, add compatibilizer, fluoropolymer modifier and remaining components in sequence, stir well and cool to obtain fluoropolymer modified PVC material.

6. Use of the fluoropolymer modified PVC material according to any one of claims 1 to 3 in the preparation of PVC pipes.

7. A PVC pipe, characterized in that: The fluoropolymer is prepared from the PVC material modified by any one of claims 1 to 3.

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