A kind of bionic hydrophobic material, hydrophobic anti-fouling PP-R pipe and its preparation method and application

Abstract

The application discloses a kind of bionic hydrophobic material, hydrophobic anti-fouling PP-R pipe and its preparation method and application.The bionic hydrophobic material of the present application, 40-60 parts of siloxane grafted polyethylene, 15-30 parts of inorganic nanoparticles are calculated according to weight fraction;The preparation method of the siloxane grafted polyethylene is: under the action of initiator, by heating melt polyethylene and vinyl-terminated polysiloxane grafting reaction, i.e. siloxane grafted polyethylene;The mass ratio of the polyethylene and vinyl-terminated polysiloxane is (20-40):(20-40).The present application simultaneously improves the hydrophobic property and mechanical property of PP-R pipe by regulating the mass ratio of polyethylene and vinyl-terminated polysiloxane, and the weight fraction of siloxane grafted polyethylene and inorganic nanoparticles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe material, more particularly to a kind of bionic hydrophobic material, hydrophobic anti-fouling PP-R pipe and its preparation method and application. BACKGROUND

[0002] PP-R pipe is a kind of plastic pipe in the field of building water supply transportation, and is widely used in drinking water transportation system. In the long-term use process, the inner wall of the existing PP-R pipe is easy to attach dirt, produce moss and breed bacteria, which affects the water quality of drinking water. Therefore, researchers have developed PP-R water supply pipe with anti-fouling property. Chinese patent (a kind of super-hydrophobic anti-fouling pipe material and its preparation method) uses polypropylene resin or polyethylene resin as base resin, and uses polysiloxane and organic modified nano-silicon dioxide particles as super-hydrophobic agent. The super-hydrophobic anti-fouling pipe material is prepared by simple mixing and extrusion, coating. Although the super-hydrophobic anti-fouling pipe material has strong hydrophobic property and can achieve the purpose of anti-fouling, its mechanical property is poor, which is not conducive to transportation and affects the service life of the pipe material.

[0003] Therefore, it is of important economic value to provide a kind of bionic hydrophobic material that can improve the hydrophobic property and mechanical property of PP-R pipe at the same time. SUMMARY

[0004] The primary object of the present application is to overcome the problem that the prior art cannot improve the hydrophobic property and mechanical property of PP-R pipe at the same time, and to provide a kind of bionic hydrophobic material.

[0005] Another object of the present application is to provide a preparation method of the bionic hydrophobic material.

[0006] Another object of the present application is to provide the application of the bionic hydrophobic material in the preparation of pipe material.

[0007] Another object of the present application is to provide a kind of hydrophobic anti-fouling PP-R pipe.

[0008] Another object of the present application is to provide a preparation method of the hydrophobic anti-fouling PP-R pipe.

[0009] The above technical objects of the present application are achieved by the following technical solutions:

[0010] A kind of bionic hydrophobic material, calculated by weight fraction, includes:

[0011] 40-60 parts of siloxane grafted polyethylene, 15-30 parts of inorganic nano-particles;

[0012] The preparation method of the siloxane grafted polyethylene is: under the action of initiator, the grafted polyethylene is obtained by heating and melting polyethylene and vinyl-terminated polysiloxane for grafting reaction;

[0013] The mass ratio of the polyethylene and the vinyl-terminated polysiloxane is (20-40):(20-40).

[0014] Compared with the polyethylene and the vinyl-terminated polysiloxane simply mixed, the siloxane grafted polyethylene obtained by the grafting reaction of the polyethylene and the vinyl-terminated polysiloxane using the initiator can improve the compatibility between the hydrophobic vinyl-terminated polysiloxane and the polypropylene resin which is the base resin of the PP-R pipe, and is conducive to improving the mechanical properties of the PP-R pipe; and can improve the regularity of the biomimetic hydrophobic material and the hydrophobic layer of the PP-R pipe, so that the molecules are arranged more orderly and closely, and can better wrap and extrude the inorganic nanoparticles to form papillae, thereby improving the hydrophobic properties of the PP-R pipe.

[0015] Moreover, the mass ratio of the polyethylene and the vinyl-terminated polysiloxane and the weight fraction of the siloxane grafted polyethylene and the inorganic nanoparticles are regulated to simultaneously improve the hydrophobic properties and the mechanical properties of the PP-R pipe, and the specific regulation is as follows:

[0016] For the mass ratio of the polyethylene and the vinyl-terminated polysiloxane, when the amount of the vinyl-terminated polysiloxane is certain, the amount of the polyethylene is too small, which means that the content of the vinyl-terminated polysiloxane is high, and although it is conducive to improving the hydrophobicity of the PP-R pipe, the amount of the polyethylene is too small, which is not conducive to improving the compatibility between the hydrophobic vinyl-terminated polysiloxane and the polypropylene resin which is the base resin of the PP-R pipe, resulting in the decline of the mechanical properties of the PP-R pipe; and when the amount of the vinyl-terminated polysiloxane is certain, the amount of the polyethylene is too large, which means that the content of the hydrophobic vinyl-terminated polysiloxane is small, and will reduce the hydrophobic properties of the PP-R pipe.

[0017] Therefore, only when the mass ratio of the polyethylene and the vinyl-terminated polysiloxane is in the range of (20-40):(20-40), the hydrophobic properties and the mechanical properties of the PP-R pipe can be simultaneously improved.

[0018] For the weight fraction of the siloxane grafted polyethylene and the inorganic nanoparticles, when the weight fraction of the inorganic nanoparticles is constant, the weight fraction of the siloxane grafted polyethylene is too small, which means that the content of the inorganic nanoparticles is too much, so that the inorganic nanoparticles are unevenly distributed in the hydrophobic layer of the PP-R pipe, resulting in stress concentration, and causing the decline of the mechanical properties of the PP-R pipe; and when the weight fraction of the siloxane grafted polyethylene is constant, the weight fraction of the inorganic nanoparticles is too small, which means that the content of the siloxane grafted polyethylene is too much, and at this time, the papillae formed by the inorganic nanoparticles have too large a spacing, resulting in the decline of the hydrophobic properties of the PP-R pipe.

[0019] Therefore, only when the weight fraction of the siloxane grafted polyethylene is 40-60 parts and the weight fraction of the inorganic nanoparticles is 15-30 parts, the hydrophobic property and the mechanical property of the PP-R pipe can be simultaneously improved.

[0020] Specifically, the average particle size of the inorganic nanoparticles is ≤100 nm.

[0021] Specifically, the polyethylene is one or more of low-density polyethylene, medium-density polyethylene or high-density polyethylene.

[0022] Further, the polyethylene is low-density polyethylene.

[0023] In the present application, compared with high-density polyethylene and medium-density polyethylene, the biomimetic hydrophobic material prepared by using low-density polyethylene has a higher melt index, which is more conducive to improving the dispersibility of the biomimetic hydrophobic material in the base resin polypropylene resin of the PP-R pipe, thereby being more conducive to simultaneously improving the hydrophobic property and the mechanical property of the PP-R pipe.

[0024] Specifically, the inorganic nanoparticles are one or more of TiO2, BaSO4, SiO2 or CaCO3.

[0025] Further, the nanoparticles are a mixture of TiO2 and BaSO4 with a mass ratio of (1-3):(1-3).

[0026] Specifically, the vinyl-terminated polysiloxane is one or more of methyl vinyl-terminated polydimethylsiloxane, vinyl-terminated polyphenylsiloxane or vinyl-terminated dimethyl methyl vinyl (siloxane and polysiloxane). Moreover, the CAS number of the monovinyl-terminated polydimethylsiloxane is 68083-19-2, the CAS number of the vinyl-terminated polyphenylsiloxane is 225927-21-9, and the CAS number of the vinyl-terminated dimethyl methyl vinyl (siloxane and polysiloxane) is 68083-18-1.

[0027] Specifically, the temperature of the heating and melting is 190-210°C.

[0028] Specifically, the initiator is one or more of diphenyl peroxide, dibenzoyl peroxide, tert-butyl benzene peroxide or azobis isobutyronitrile.

[0029] A preparation method of a biomimetic hydrophobic material, comprising the following steps:

[0030] Mixing the siloxane grafted polyethylene and the inorganic nanoparticles to obtain the biomimetic hydrophobic material.

[0031] The above-mentioned biomimetic hydrophobic material in the preparation of pipe material should also be within the protection scope of the present application.

[0032] A hydrophobic anti-fouling PP-R pipe, from inside to outside, in turn, a hydrophobic layer, an impact layer and a protective layer, calculated by weight fraction: the hydrophobic layer comprises: 100 parts of polypropylene resin, 3-9 parts of biomimetic hydrophobic material, 5-10 parts of cross-linked polyethylene (PEX);

[0033] The impact layer comprises: 100 parts of polypropylene resin, 5-10 parts of impact agent, 5-10 parts of cross-linked polyethylene (PEX).

[0034] The application promotes the micro-crosslinking of the hydrophobic layer and the impact layer by adding cross-linked polyethylene (PEX) in the hydrophobic layer and the impact layer of the PP-R pipe, and the substance formed after micro-crosslinking has a three-dimensional structure, which is beneficial to improve the bonding force between the hydrophobic layer and the impact layer and the strength of the PP-R pipe, thereby further improving the mechanical properties of the PP-R pipe.

[0035] Specifically, the hydrophobic layer comprises: 100 parts of polypropylene resin, 3-9 parts of biomimetic hydrophobic material, 5-10 parts of cross-linked polyethylene (PEX), and 3-5 parts of color master.

[0036] Specifically, the impact layer comprises: 100 parts of polypropylene resin, 5-10 parts of impact agent, 5-10 parts of cross-linked polyethylene (PEX), and 3-5 parts of color master.

[0037] Specifically, the protective layer comprises: 100 parts of polypropylene resin, 3-5 parts of color master.

[0038] Specifically, the weight average molecular weight of the polypropylene resin is 0.6-1 million.

[0039] Further, the weight average molecular weight of the polypropylene resin is 0.81 million.

[0040] Specifically, the impact agent is one or more of POE (thermoplastic elastomer), EDPM (ethylene-propylene rubber) or SBS (thermoplastic butadiene block copolymer or thermoplastic butadiene rubber).

[0041] Any conventional color master in the art can be used in the application.

[0042] Specifically, the thickness of the hydrophobic layer is 0.2-1.2 mm.

[0043] Further, the thickness of the hydrophobic layer is 0.2-0.8 mm.

[0044] Specifically, the thickness of the impact layer is 0.9-1.2 mm.

[0045] Specifically, the thickness of the protective layer is 1.4-1.7 mm.

[0046] A preparation method of a hydrophobic anti-fouling PP-R pipe, comprising the following steps:

[0047] Mixing each layer component of the hydrophobic layer, the impact layer and the protective layer respectively, using a three-layer co-extrusion die, heating and extruding, cooling and forming, thus obtaining the hydrophobic and anti-fouling PP-R pipe.

[0048] Specifically, the preparation method of the hydrophobic and anti-fouling PP-R pipe comprises the following steps:

[0049] Mixing each layer component of the hydrophobic layer, the impact layer and the protective layer respectively, using a three-layer co-extrusion die, using a main extruder to extrude the impact layer, using a first co-extrusion auxiliary machine to extrude the hydrophobic layer, using a second co-extrusion auxiliary machine to extrude the protective layer, using a third co-extrusion auxiliary machine to extrude the color strip, heating, composite co-extrusion, cooling and forming, and cutting, thus obtaining the hydrophobic and anti-fouling PP-R pipe.

[0050] Specifically, the heating temperature is 180-200 DEG C.

[0051] Compared with the prior art, the present application has the following beneficial effects:

[0052] Compared with simply mixed polyethylene and vinyl-terminated polysiloxane, the siloxane grafted polyethylene obtained by using an initiator to make polyethylene and vinyl-terminated polysiloxane undergo grafting reaction, on the one hand, improves the compatibility between the hydrophobic vinyl-terminated polysiloxane and the base resin polypropylene resin of the PP-R pipe, which is beneficial to improving the mechanical properties of the PP-R pipe; on the other hand, improves the regularity of the biomimetic hydrophobic material and the hydrophobic layer of the PP-R pipe, so that the molecules are arranged more orderly and closely, which can better wrap and extrude inorganic nanoparticles to form papillae, thereby improving the hydrophobic properties of the PP-R pipe.

[0053] Moreover, the present application simultaneously improves the hydrophobic properties and the mechanical properties of the PP-R pipe by adjusting the mass ratio of polyethylene and vinyl-terminated polysiloxane, and the weight fraction of siloxane grafted polyethylene and inorganic nanoparticles. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of the hydrophobic and anti-fouling PP-R pipe of Example 1. DETAILED DESCRIPTION

[0055] The present application will be further described in conjunction with the examples. These examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods not specified in the following example are usually carried out according to the conventional conditions in the art or according to the conditions suggested by the manufacturers; the raw materials, reagents and the like used, if not specifically stated, are all raw materials and reagents that can be obtained through commercial channels such as conventional markets. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application shall fall within the scope of the present application.

[0056] In the embodiments and comparative examples of the present application:

[0057] Melt index of the biomimetic hydrophobic material: perform national standard GB / T3682.1-2018, test under the condition of 190℃, 2.16kg;

[0058] Initiator: azobis isobutyronitrile, CAS number: 78-67-1, Liaoning Shuangqi Fine Chemical Co., Ltd.;

[0059] Vinyl-terminated polysiloxane: methyl vinyl-terminated polydimethylsiloxane, CAS number: 68083-19-2, Guangzhou Shanghe Chemical Technology Co., Ltd.;

[0060] High-density polyethylene (HDPE): China Petroleum Jilin Petrochemical Co., Ltd., JHMGL 100S, melt index 0.26g / 10min (190℃, 5.0kg);

[0061] Medium-density polyethylene (MDPE): Nordic Chemical Co., Ltd., ME3446, melt index 0.80g / 10min (190℃, 5.0kg);

[0062] Low-density polyethylene (LDPE): Sinopec Yanshan Petrochemical Co., Ltd., LD100, melt index 2.0g / 10min (190℃, 5.0kg);

[0063] Polypropylene resin: Korea Xiaoxing Group, R200P, weight average molecular weight 810,000, melt index 0.25g / 10min (230℃, 2.16kg);

[0064] The average particle size of TiO2 is 90nm, which can be obtained by self-made or purchased on the market, such as VK-T100 purchased from Xuancheng Jingrui New Material Co., Ltd.;

[0065] The average particle size of BaSO4 is 50nm, which can be obtained by self-made or purchased on the market, such as purchased from China Gold Research (Beijing) Technology Co., Ltd.;

[0066] The average particle size of SiO2 is 50nm, which can be obtained by self-made or purchased on the market, such as VK-SP50 purchased from Hangzhou Zemeng New Material Co., Ltd.;

[0067] The average particle size of CaCO3 is 75nm, which can be obtained by self-made or purchased on the market, such as XFI11-2 purchased from Nanjing Xianfeng Nanometer Material Technology Co., Ltd.;

[0068] Impact modifier: SBS, Sinopec Baling Petrochemical Co., Ltd., YH-792E;

[0069] Crosslinked polyethylene (PEX): LG Chemical, XL-1800;

[0070] Color masterbatch for hydrophobic layer: Heshan Xingzhan Plastic Co., Ltd., SM103;

[0071] Color masterbatch for impact layer: Dongguan Chuangte Plastic Technology Co., Ltd., CT1027F;

[0072] Color masterbatch for protective layer: Heshan Xingzhan Plastic Co., Ltd., SM618;

[0073] Heat-resistant polyethylene PE-RT: PetroChina Dushanzi Petrochemical Company, DGD24620, melt index 0.68 g / 10 min (190℃, 5.0 kg).

[0074] Example 1

[0075] The present embodiment provides a biomimetic hydrophobic material, which comprises, by weight fraction:

[0076] 50 parts of siloxane grafted polyethylene, 20 parts of inorganic nanoparticles;

[0077] The preparation method of the siloxane grafted polyethylene is as follows: under the action of 100 g of initiator, 3000 g of low-density polyethylene and 3000 g of vinyl-terminated polysiloxane are subjected to grafting reaction by heating to 140℃ for 3 h, washed with ethanol for multiple times, and vacuum dried at 70℃ to obtain the siloxane grafted polyethylene;

[0078] A preparation method of a biomimetic hydrophobic material, comprising the following steps:

[0079] Mixing the siloxane grafted polyethylene and the inorganic nanoparticles to obtain the biomimetic hydrophobic material;

[0080] A hydrophobic and anti-fouling PP-R pipe, which comprises, from inside to outside, a hydrophobic layer, an impact layer and a protective layer, and each layer comprises the following components, by weight fraction:

[0081] The hydrophobic layer comprises: 100 parts of polypropylene resin, 5 parts of biomimetic hydrophobic material, 5 parts of crosslinked polyethylene (PEX), and 3 parts of color masterbatch;

[0082] The impact layer comprises: 100 parts of polypropylene resin, 5 parts of impact agent, 5 parts of crosslinked polyethylene (PEX), and 3 parts of color masterbatch;

[0083] The protective layer comprises: 100 parts of polypropylene resin, and 5 parts of color masterbatch;

[0084] A preparation method of a hydrophobic and anti-fouling PP-R pipe, comprising the following steps:

[0085] The components of the hydrophobic layer, the impact layer and the protective layer were mixed in the barrel respectively for 5 min, a three-layer co-extrusion die was used, the impact layer was extruded by the main extruder, the hydrophobic layer was extruded by the first co-extrusion auxiliary machine, the protective layer was extruded by the second co-extrusion auxiliary machine, and the color strip was extruded by the third co-extrusion auxiliary machine, heating to 200℃, composite co-extrusion, the extrusion speed was 10 m / min, gradient cooling was used to form, and cutting was performed, thereby obtaining the hydrophobic and anti-fouling PP-R pipe;

[0086] The thickness of the hydrophobic layer is 0.5 mm; the thickness of the impact layer is 1.2 mm; and the thickness of the protective layer is 1.7 mm. Figure 1 It is a structural schematic diagram of the hydrophobic and anti-fouling PP-R pipe of Example 1, I-hydrophobic layer, II-impact layer, III-protective layer, dn-outer diameter of the hydrophobic and anti-fouling PP-R pipe, e1-total thickness of the hydrophobic layer, the impact layer and the protective layer, e2-thickness of the hydrophobic layer, e3-thickness of the protective layer, and L-average length of the hydrophobic and anti-fouling PP-R pipe; the outer diameter of the hydrophobic and anti-fouling PP-R pipe is 20 mm.

[0087] The mass ratio of the low-density polyethylene and the vinyl-terminated polysiloxane is 30:30.

[0088] The inorganic nanoparticles are a mixture of TiO2 and BaSO4 with a mass ratio of 1:1.

[0089] Examples 2-5 and Comparative Examples 1-4

[0090] Examples 2-5 and Comparative Examples 1-4 provide a biomimetic hydrophobic material and a hydrophobic and anti-fouling PP-R pipe, which are different from Example 1 only in that the mass ratio of the low-density polyethylene and the vinyl-terminated polysiloxane used to prepare the siloxane grafted polyethylene is different, and the rest are consistent with Example 1, as shown in the following table:

[0091] Table 1 Dosage of each component of the biomimetic hydrophobic material of Examples 1-5 and Comparative Examples 1-4

[0092]

[0093] Examples 6-9 and Comparative Examples 5-6

[0094] Examples 6-9 and Comparative Examples 5-6 provide a biomimetic hydrophobic material and a hydrophobic and anti-fouling PP-R pipe, which are different from Example 1 only in that the weight fraction of the siloxane grafted polyethylene and the inorganic nanoparticles used to prepare the biomimetic hydrophobic material is different, and the rest are consistent with Example 1, as shown in the following table:

[0095] Table 2 Weight fraction of siloxane grafted polyethylene and inorganic nanoparticles of Examples 1, 6-9 and Comparative Examples 5-6

[0096]

[0097] Examples 10-11

[0098] Examples 10-11 provide a biomimetic hydrophobic material and a hydrophobic and scale resistant PP-R pipe, which are different from Example 1 only in that the polyethylene species used to prepare the biomimetic hydrophobic material is different, and the rest are consistent with Example 1, as shown in the following table:

[0099] Table 3 Polyethylene species used to prepare the biomimetic hydrophobic material in Examples 1 and 10-11

[0100] Polyethylene species Example 1 Low density polyethylene Example 10 Medium density polyethylene Example 11 High density polyethylene

[0101] Example 12

[0102] This example provides a biomimetic hydrophobic material and a hydrophobic and scale resistant PP-R pipe, which are different from Example 1 only in that the hydrophobic layer and the impact layer do not add cross-linked polyethylene (PEX), and the rest are consistent with Example 1.

[0103] Examples 13-16

[0104] Examples 13-16 provide a biomimetic hydrophobic material and a hydrophobic and scale resistant PP-R pipe, which are different from Example 1 only in that the type of inorganic nanoparticles is different, and the rest are consistent with Example 1, as shown in the following table:

[0105] Table 4 Type of inorganic nanoparticles in Examples 1 and 13-16

[0106] Inorganic nanoparticle species Example 1 A mixture of TiO2and BaSO4in a mass ratio of 1 :1 Example 13 A mixture of Ti02and BaS04in a mass ratio of 1 :3 Example 14 TiO2and BaSO4 mixture in a mass ratio of 3:1 Example 15 [CAT] only for SiO2 Example 16 [CaCO3 only]

[0107] Comparative Example 7

[0108] This comparative example provides a biomimetic hydrophobic material, which comprises, by weight fraction:

[0109] 50 parts of a siloxane-polyethylene mixture, 20 parts of inorganic nanoparticles;

[0110] The preparation method of the siloxane-polyethylene mixture is to directly mix low-density polyethylene and vinyl-terminated polysiloxane in a mass ratio of 30:30;

[0111] A preparation method of a biomimetic hydrophobic material, comprising the following steps:

[0112] Mixing the siloxane-polyethylene mixture and the inorganic nanoparticles to obtain the biomimetic hydrophobic material;

[0113] A hydrophobic and scale resistant PP-R pipe, consistent with Example 1;

[0114] A preparation method of a hydrophobic and scale resistant PP-R pipe, consistent with Example 1;

[0115] The inorganic nanoparticles are a mixture of TiO2 and BaSO4 in a mass ratio of 1:1.

[0116] Comparative Example 8

[0117] This comparative example provides a biomimetic hydrophobic material and a hydrophobic anti-fouling PP-R pipe, in which low-density polyethylene is replaced by polypropylene (PP), and the rest is consistent with Example 1.

[0118] Comparative Example 9

[0119] This comparative example provides a biomimetic hydrophobic material and a hydrophobic anti-fouling PP-R pipe, in which low-density polyethylene is replaced by heat-resistant polyethylene PE-RT, and the rest is consistent with Example 1.

[0120] Performance test

[0121] The PP-R pipes of each embodiment and the comparative example of the present application are tested for hydrophobic performance and mechanical performance:

[0122] (1) Hydrophobic performance test:

[0123] The contact angle of the PP-R pipes of each embodiment or the comparative example of the present application is tested according to GB / T 30693-2014 "Measurement of Water Contact Angle of Plastic Film";

[0124] After simulating the actual application scenario and performing water flow scouring for 1000h under the condition of water flow 5.52m 3 / h, the contact angle is detected, which is the contact angle after 1000h of scouring; the greater the difference between the contact angle after 1000h of scouring and the contact angle without water flow scouring, the worse the long-term stability of the hydrophobic performance of the PP-R pipe;

[0125] (2) Mechanical performance test:

[0126] The tensile strength of the PP-R pipes of each embodiment or the comparative example of the present application is tested according to GB / T 1040.2-2006 "Test Methods for Tensile Properties of Plastics";

[0127] The burst strength of the PP-R pipes of each embodiment or the comparative example of the present application is tested according to GB / T 15560-1995 "Hydraulic Instantaneous Bursting and Pressure Resistance Test Method for Plastic Pipes for Fluid Transport";

[0128] The hydrostatic strength of the PP-R pipes of each embodiment or the comparative example of the present application is tested under the conditions of 95℃, 165h and 3.8MPa pressure according to GB / T 6111-2018 "Determination of Internal Pressure Resistance of Thermoplastic Pipe Systems for Fluid Transport";

[0129] The experimental results are shown in the following table:

[0130] Table 5 Test results of Examples 1-5 and Comparative Examples 1-4

[0131]

[0132]

[0133] From Table 5, it can be seen that, for the mass ratio of polyethylene and vinyl-terminated polysiloxane, when the amount of vinyl-terminated polysiloxane is constant, too little amount of polyethylene means high content of vinyl-terminated polysiloxane, which is beneficial to improve the hydrophobicity of the PP-R pipe, but too little amount of polyethylene is not conducive to improving the compatibility between the hydrophobic vinyl-terminated polysiloxane and the base resin polypropylene resin of the PP-R pipe, resulting in a decrease in the mechanical properties of the PP-R pipe; and when the amount of vinyl-terminated polysiloxane is constant, too much amount of polyethylene means low content of hydrophobic vinyl-terminated polysiloxane, thereby reducing the hydrophobicity of the PP-R pipe.

[0134] Therefore, only when the mass ratio of polyethylene and vinyl-terminated polysiloxane is in the range of (20-40):(20-40), can the hydrophobicity and the mechanical properties of the PP-R pipe be improved at the same time.

[0135] Table 6 Test results of Examples 1, 6-9 and Comparative Examples 5-6

[0136]

[0137] From Table 6, it can be seen that, for the weight fraction of siloxane-grafted polyethylene and inorganic nanoparticles, when the weight fraction of inorganic nanoparticles is constant, too little weight fraction of siloxane-grafted polyethylene means too much content of inorganic nanoparticles, which makes the inorganic nanoparticles unevenly distributed in the hydrophobic layer of the PP-R pipe, resulting in stress concentration and a decrease in the mechanical properties of the PP-R pipe; and when the weight fraction of siloxane-grafted polyethylene is constant, too little weight fraction of inorganic nanoparticles means too much content of siloxane-grafted polyethylene, in which case the distance between the bumps formed by the inorganic nanoparticles is too large, resulting in a decrease in the hydrophobicity of the PP-R pipe.

[0138] Therefore, only when the weight fraction of siloxane-grafted polyethylene is 40-60 parts and the weight fraction of inorganic nanoparticles is 15-30 parts, can the hydrophobicity and the mechanical properties of the PP-R pipe be improved at the same time.

[0139] Table 7 Test results of Examples 1 and 10-11

[0140]

[0141] From Table 7, it can be seen that, in the present application, compared with high-density polyethylene and medium-density polyethylene, the biomimetic hydrophobic material prepared by using low-density polyethylene has a higher melt index, which is more conducive to improving the dispersibility of the biomimetic hydrophobic material in the base resin polypropylene resin of the PP-R pipe, thereby being more conducive to simultaneously improving the hydrophobic performance and mechanical performance of the PP-R pipe.

[0142] Table 8 Test results of Examples 1, 12 and Comparative Examples 7-9

[0143]

[0144] In the table, the contact angle in the second column is the contact angle without water flow scouring, and the greater the difference between the contact angle after scouring for 1000h and the contact angle without water flow scouring, the poorer the long-term stability of the hydrophobic performance of the PP-R pipe.

[0145] From Table 8, it can be seen that:

[0146] By comparing Example 1 and Example 12, it can be seen that, in Example 1 of the present application, cross-linked polyethylene (PEX) is added to the hydrophobic layer and the impact layer of the PP-R pipe to promote micro-cross-linking of the hydrophobic layer and the impact layer, and the substances formed after micro-cross-linking have a three-dimensional structure, which is conducive to improving the bonding force between the hydrophobic layer and the impact layer and the strength of the PP-R pipe, thereby further improving the mechanical performance of the PP-R pipe.

[0147] Compared with the polyethylene and the vinyl-terminated polysiloxane simply mixed in Comparative Example 7, the siloxane-grafted polyethylene obtained by grafting reaction of the polyethylene and the vinyl-terminated polysiloxane by using the initiator in Example 1 of the present application, on the one hand, improves the compatibility between the hydrophobic vinyl-terminated polysiloxane and the base resin polypropylene resin of the PP-R pipe, which is conducive to improving the mechanical performance of the PP-R pipe; on the other hand, improves the regularity of the biomimetic hydrophobic material and the hydrophobic layer of the PP-R pipe, so that the molecules are arranged more orderly and closely, which can better wrap and extrude inorganic nanoparticles to form papillae, thereby further improving the hydrophobic performance of the PP-R pipe.

[0148] When the polypropylene of Comparative Example 8 or the heat-resistant polyethylene PE-RT of Comparative Example 9 is used instead of the low-density polyethylene of Example 1, it is found that the polypropylene and the heat-resistant polyethylene PE-RT have a poorer ability to improve the compatibility between the vinyl-terminated polysiloxane and the base resin polypropylene resin of the PP-R pipe than the low-density polyethylene, and therefore, the PP-R pipes of Comparative Examples 8 and 9 have poorer mechanical performance than Example 1, and also have a certain influence on the hydrophobic performance of the PP-R pipes of Comparative Examples 8 and 9.

[0149] Table 9 Test results of Examples 1 and 13-16

[0150]

[0151] From Table 9, it can be seen that:

[0152] The type of inorganic nanoparticles has certain influence on the hydrophobic property and mechanical property of the PP-R pipe.

[0153] Obviously, the above embodiments of the present application are merely exemplary for clearly illustrating the present application, but not limitation on the embodiments of the present application. Other different forms of changes or variations can be made on the basis of the above description for those skilled in the art. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A biomimetic hydrophobic material, characterized in that, By weight parts, comprising: 40~60 parts of siloxane grafted polyethylene, 15~30 parts of inorganic nanoparticles; The preparation method of the siloxane grafted polyethylene is: under the action of an initiator, a grafting reaction is carried out by heating and melting polyethylene and a vinyl-terminated polysiloxane, thereby obtaining the siloxane grafted polyethylene; The mass ratio of the polyethylene and the vinyl-terminated polysiloxane is (20~40):(20~40); The inorganic nanoparticles are a mixture of TiO2 and BaSO4 with a mass ratio of 1:1; The preparation method of the biomimetic hydrophobic material comprises the following steps: mixing the siloxane grafted polyethylene and the inorganic nanoparticles, thereby obtaining the biomimetic hydrophobic material.

2. The biomimetic hydrophobic material of claim 1, wherein, The average particle size of the inorganic nanoparticles is ≤100 nm.

3. The biomimetic hydrophobic material of claim 1, wherein, The polyethylene is one or more of low-density polyethylene, medium-density polyethylene or high-density polyethylene.

4. The biomimetic hydrophobic material of claim 1, wherein, The vinyl-terminated polysiloxane is one or more of methyl vinyl-terminated polydimethylsiloxane, vinyl-terminated polyphenylsiloxane or vinyl-terminated dimethyl methyl vinyl polysiloxane.

5. Use of the biomimetic hydrophobic material according to any one of claims 1~4 in the preparation of a pipe.

6. A hydrophobic, scale resistant PP-R pipe, characterized in that, From the inside to the outside, the hydrophobic layer, the impact layer and the protective layer are sequentially arranged, and by weight parts, the hydrophobic layer comprises: 100 parts of polypropylene resin, 3~9 parts of the biomimetic hydrophobic material according to any one of claims 1~4, and 5~10 parts of crosslinked polyethylene. The impact layer comprises: 100 parts of polypropylene resin, 5~10 parts of an impact agent, and 5~10 parts of crosslinked polyethylene.

7. The hydrophobic, scale resistant PP-R pipe according to claim 6, characterized in that The thickness of the hydrophobic layer is 0.2~1.2 mm.

8. A process for the preparation of the hydrophobic, scale resistant PP-R pipe according to claim 6 or 7, characterized in that, The method comprises the following steps: The components of the hydrophobic layer, the impact layer and the protective layer are respectively mixed, a three-layer co-extrusion die is used, and the mixture is heated and extruded, and then cooled and formed, thereby obtaining the hydrophobic and anti-fouling PP-R pipe.

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