Anticorrosion and wear-resistant pipeline coating and its production process

Abstract

This application discloses an anti-corrosion and wear-resistant pipe coating and its manufacturing process, belonging to the technical field of anti-corrosion and wear-resistant pipe coatings. The pipe coating includes a first coating formed by curing a first component on the pipe wall and a second coating formed by curing a second component on the outside of the first coating. The first component includes 80-100 parts epoxy resin, 5-10 parts monomer containing at least two thiol groups, 5-10 parts monomer A, 10-20 parts diluent, 40-50 parts filler, 2-4 parts defoamer, 2-4 parts leveling agent, 2-5 parts dispersant, 8-15 parts ethylenediamine, 1 part photoinitiator, and 10-25 parts solvent. Monomer A has the following structural formula 1 and / or 2. The second component includes 80-120 parts polyethylene resin, 10-15 parts polyvinyl butyral, 20-30 parts toughening agent, 30-50 parts filler, and 3-8 parts leveling agent. The pipeline coating improves the overall weather resistance and wear resistance of the anti-corrosion and wear-resistant pipeline coating by adding monomers containing at least two mercapto groups and monomer A to the epoxy resin matrix of the first coating and polyvinyl butyral to the second coating.

Description

Technical Field

[0001] This application relates to an anti-corrosion and wear-resistant pipe coating and its manufacturing process, belonging to the technical field of anti-corrosion and wear-resistant pipe coatings. Background Technology

[0002] Currently, pipelines can be used to transport fluids of various properties. In order to prevent the pipeline from being corroded by the transported fluid medium, the external environmental medium, the metabolic activities of microorganisms, electrochemical effects, etc., the pipeline wall needs to be coated with anti-corrosion medium to extend the service life of the pipeline.

[0003] Current research focuses primarily on improving the corrosion resistance of anti-corrosion coatings in acidic, alkaline, or harsh media. This is mainly achieved by adding modifying components. While this approach can improve the corrosion resistance of pipe coatings, it often neglects the coating's weather resistance and results in poor abrasion resistance. Pipelines exposed to the elements for extended periods or requiring heating are not effectively protected and often need replacement after only one or two years. This not only wastes human and financial resources but also generates a large amount of waste coating material, increasing the difficulty of disposal. Summary of the Invention

[0004] To address the aforementioned issues, a corrosion-resistant and wear-resistant pipe coating is provided. This coating improves the weather resistance and wear resistance of the first coating by adding monomers containing at least two thiol groups and monomer A to the epoxy resin matrix of the first coating, thereby forming a cross-linked network. Furthermore, by adding polyvinyl butyral to the polyethylene resin matrix of the second coating, the weather resistance and wear resistance of the second coating are improved, thus enhancing the overall weather resistance and wear resistance of the corrosion-resistant and wear-resistant pipe coating. Simultaneously, the combination of the first and second coatings improves their bonding strength and maintains good corrosion resistance.

[0005] According to one aspect of this application, a corrosion-resistant and wear-resistant pipe coating is provided, the coating comprising a first coating formed by curing a first component on a pipe wall and a second coating formed by curing a second component on the outside of the first coating;

[0006] The first component comprises 80-100 parts epoxy resin, 5-10 parts monomer containing at least two thiol groups, 5-10 parts monomer A, 10-20 parts diluent, 40-50 parts filler, 2-4 parts defoamer, 2-4 parts leveling agent, 2-5 parts dispersant, 8-15 parts ethylenediamine, 1 part photoinitiator, and 10-25 parts solvent, wherein monomer A has the following structural formula 1 and / or 2:

[0007]

[0008] The second component comprises 80-120 parts of polyethylene resin, 10-15 parts of polyvinyl butyral, 20-30 parts of toughening agent, 30-50 parts of filler and 3-8 parts of leveling agent.

[0009] This anti-corrosion and wear-resistant pipe coating can be formed on the inner surface of the pipe, the outer surface of the pipe, or both the inner and outer surfaces of the pipe simultaneously. Those skilled in the art can prepare it according to actual needs.

[0010] The first coating is formed by the first component. The epoxy resin is cured to form a first cross-linked network. The first component of this application is based on epoxy resin, with the addition of a monomer containing at least two thiol groups, monomer A, and a photoinitiator. During the curing process of the first coating, the monomer containing at least two thiol groups and monomer A are polymerized under the action of the photoinitiator to form a second cross-linked network. The two cross-linked networks can interpenetrate each other, and the interaction force between atoms is enhanced, thereby improving the wear resistance and weather resistance of the first coating, enabling it to be used for a long time in high temperature and high oxygen environment.

[0011] Furthermore, monomer A contains NH or NH2 groups, which can participate in the curing of epoxy resin, improve the compatibility between the second crosslinking network and the first crosslinking network, and increase the density of the first coating, thereby preventing contact between corrosive media and the pipe wall and improving the corrosion resistance of the first coating. The ester groups contained in monomer A can also improve the compatibility with the epoxy resin crosslinking network and increase the adsorption of the first crosslinking network on the pipe wall, thereby improving the bonding force with the pipe wall. The presence of C=N bonds can improve the stability of the second crosslinking network, thus significantly improving the weather resistance of the first coating.

[0012] The addition of polyvinyl butyral to the second coating increases its compatibility with polyethylene resin, improves its weather resistance and abrasion resistance, enhances its adhesion to the first coating, and also improves its scratch resistance, reducing scratches on the abrasion-resistant and anti-corrosion coating during construction or use, thus extending its service life.

[0013] Optionally, the monomer containing at least two thiol groups is selected from at least one of 1,4-dimercapto-2,3-butanediol, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, di(mercaptoacetic acid)-1,4-butanediol ester, and ethylene glycol dimercaptoacetate.

[0014] Optionally, the monomer containing at least two thiol groups is selected from pentaerythritol tetrakis(3-mercaptopropionic acid) and di(mercaptoacetic acid)-1,4-butanediol.

[0015] A monomer containing at least two thiol groups reacts with the double bond of monomer A to form a second crosslinking network. The two substances are crosslinked through pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and the chain length between adjacent crosslinking points of the second crosslinking network is extended through di(mercaptoacetic acid)-1,4-butanediol ester. Both substances also contain ester groups, which can further improve the compatibility with the first crosslinking network and increase the density of the first coating, so that the first coating forms a dense protective layer on the pipe wall.

[0016] Optionally, the molar ratio of the tetra(3-mercaptopropionic acid) pentaerythritol ester and the di(mercaptoacetic acid)-1,4-butanediol ester is 1:4.

[0017] The above molar ratio ensures that the crosslinking points of the second crosslinking network and the molecular chain length between adjacent crosslinking points are moderate, thus achieving optimal wear resistance, weather resistance, and corrosion resistance of the first coating. If there is too much pentaerythritol tetrakis(3-mercaptopropionic acid) ester, the number of crosslinking points in the second crosslinking network will increase, leading to increased brittleness of the first coating and a decrease in both wear resistance and weather resistance. If there is too little pentaerythritol tetrakis(3-mercaptopropionic acid) ester, the number of crosslinking points in the second crosslinking network will increase or it will fail to crosslink, thus failing to interact with the first crosslinking network. Similarly, wear resistance, weather resistance, and corrosion resistance will also decrease.

[0018] Optionally, the photoinitiator is benzoyl dimethyl ether.

[0019] Optionally, the filler is selected from at least one of titanium dioxide, silicon dioxide, hydroxyapatite, barium sulfate, talc, and wollastonite.

[0020] Optionally, the monomer A is a mixture of structural formulas 1 and 2, wherein the molar ratio of structural formula 1 to structural formula 2 is 7:3.

[0021] The above two molar ratios of structural formula 1 and structural formula 2 enable the first coating to have the best wear resistance, weather resistance and corrosion resistance, and the first coating to have the strongest adhesion to the pipe and the second coating.

[0022] Optionally, monomer A is prepared by reacting p-acetoxystyrene, formaldehyde compounds and 2-aminoimidazole in a molar ratio of 1:(1-3):(1-2) under an acidic catalyst.

[0023] Optionally, the temperature for preparing monomer A from p-acetoxystyrene, formaldehyde compounds, and 2-aminoimidazole is 50-60°C, and the time is 7-12 hours.

[0024] This preparation method can prepare monomers A of both structural formula 1 and structural formula 2. Studies have found that the higher the temperature, the more structural formula 1 is generated. At a temperature of 60℃, more than 90% of the obtained monomers are of structural formula 1, and at a temperature of 50℃, the proportion of monomers A of structural formula 1 is 60-70%. All of the above proportions refer to molar ratios.

[0025] Optionally, the formaldehyde compound is selected from at least one of formaldehyde, trioxymethylene, and paraoxymethylene.

[0026] Optionally, the coating further includes a wear-resistant material that is melt-cast onto the surface of the second coating to form a wear-resistant layer, wherein the wear-resistant material accounts for 30%-50% of the total weight of the second component.

[0027] The second coating comes into contact with the wear-resistant layer. The wear-resistant material is embedded into the surface of the second coating through a spraying process. Verification has shown that the presence of polyvinyl butyral (PVB) improves the bonding between the wear-resistant material and the second coating, resulting in a stronger bond between the two layers. This prevents delamination between the two layers, ensuring long-term protection of the pipeline. The wear-resistant layer enhances the pipeline's wear resistance and scratch resistance, preventing damage during installation and transportation, thus extending the pipeline's service life, preventing media leakage, and improving the pipeline's safe transport capacity.

[0028] Optionally, the wear-resistant material is selected from at least one of silicon carbide, diamond, silicon micro powder, and alumina.

[0029] Optionally, the wear-resistant material is silicon carbide and diamond, and the weight ratio of silicon carbide to diamond is 1:(1-2).

[0030] Optionally, the silicon carbide has a particle size of 5-10 μm, and the diamond has a particle size of 1-3 μm.

[0031] Using silicon carbide and diamond, which have high hardness, is the best way to improve the wear resistance and scratch resistance of pipelines. Furthermore, at the above weight ratio and particle size, the density of the wear-resistant layer can be increased and the gaps in the wear-resistant layer can be reduced, thereby preventing corrosive media from entering the wear-resistant layer and improving the corrosion resistance of the pipeline. At the same time, both have high temperature resistance and low coefficient of thermal expansion, so they can maintain good corrosion resistance, wear resistance and scratch resistance even at high temperatures.

[0032] Optionally, the wear-resistant material is a wear-resistant material surface-modified with polyvinyl butyral. The wear-resistant material is placed in a polyvinyl butyral solution and kept at 50-70℃ for 2-4 hours, then filtered and dried to obtain the final product. Modifying the wear-resistant material with polyvinyl butyral allows the polyvinyl butyral to be loaded onto the surface of the wear-resistant material, thereby further increasing the bonding force between the wear-resistant layer and the second coating, and also increasing the bonding between the wear-resistant materials themselves, thus improving the density of the wear-resistant layer. This forms layers of protective film on the surface and inside the wear-resistant layer, improving the pipeline's corrosion resistance, wear resistance, and scratch resistance.

[0033] Optionally, the anti-corrosion material further includes 20-50 parts of cashew phenol-benzoxazine resin, which is cured on the surface of the wear-resistant layer to form a third coating.

[0034] From a microscopic perspective, the surface of the wear-resistant layer is uneven. A third coating is obtained by curing with cashew phenol-based benzoxazine resin, which can cover the surface of the wear-resistant material, thereby sealing the small gaps in the wear-resistant layer and improving the smoothness of the overall anti-corrosion coating. This prevents the wear-resistant layer from disintegrating when subjected to media corrosion, thus improving the corrosion resistance of the pipeline.

[0035] Meanwhile, the cashew phenol-based benzoxazine resin has good compatibility with polyvinyl butyral, and the wear-resistant material modified with polyvinyl butyral also has good adhesion to the third coating, thus avoiding delamination between the wear-resistant layer and the third coating.

[0036] Optionally, the thickness of the first coating is 400-600 μm, the thickness of the second coating is 300-800 μm, the thickness of the wear-resistant layer is 100-300 μm, and the thickness of the third coating is 40-100 μm.

[0037] According to another aspect of this application, a manufacturing process for the anti-corrosion and wear-resistant pipe coating described in any of the above claims is provided, comprising the following steps:

[0038] (1) The first coating is obtained by mixing the above epoxy resin, polyvinyl butyral, monomer containing at least two mercapto groups, monomer A, diluent, filler, defoamer, leveling agent, dispersant, ethylenediamine, photoinitiator and solvent, coating it on the pipe wall and curing it.

[0039] (2) Mix the above-mentioned polyethylene resin, toughening agent, filler and leveling agent, extrude and granulate, grind and then spray on the first coating to form the second coating, thus obtaining the anti-corrosion and wear-resistant pipe coating.

[0040] Optionally, in step (1), the curing process is divided into three stages:

[0041] First stage: Curing at 40℃-60℃ for 1-2 hours;

[0042] Second stage: Curing under ultraviolet light for 10-40 minutes;

[0043] Third stage: Curing at 40℃-60℃ for more than 3 hours.

[0044] In the first stage of this preparation method, epoxy resin is pre-crosslinked in the presence of triethylamine and monomer A. In the second stage, monomer A and a monomer containing at least two thiol groups are crosslinked under the action of ultraviolet light and a photoinitiator to form a second crosslinked network. In the third stage, the first crosslinked network is constructed. This curing method enables the interpenetration of the first and second crosslinked networks, improves the bonding and compatibility of the two crosslinked networks, and thus improves the wear resistance and weather resistance of the first coating.

[0045] Optionally, in step (2), the temperature of the extrusion granulation is 200℃-240℃.

[0046] Optionally, the preparation method further includes the following steps:

[0047] (3) The wear-resistant material is melt-sprayed onto the surface of the second coating to form a wear-resistant layer;

[0048] (4) Coat the surface of the wear-resistant layer with cashew phenol benzoxazine resin and cure at 85-100℃ for at least 8 hours to form a third coating.

[0049] By modifying the first and second components and adding the wear-resistant layer and third coating, the protective effect of the anti-corrosion material on the pipeline can be significantly improved. When the anti-corrosion material is applied to the pipeline wall, it can simultaneously improve the pipeline's corrosion resistance, wear resistance, and scratch resistance, extend the pipeline's service life, and improve the pipeline's safety in use.

[0050] The beneficial effects of this application include, but are not limited to:

[0051] 1. The anti-corrosion and wear-resistant pipe coating of this application consists of a first coating and a second coating. The two coatings have good adhesion, which can provide dense protection for the pipe surface and improve the overall wear resistance and weather resistance of the coating.

[0052] 2. The anti-corrosion and wear-resistant pipe coating of this application contains monomers containing at least two mercapto groups and monomer A in the first coating, which can form an interpenetrating cross-linked network with the epoxy resin network. The proportion of the monomers is conducive to the formation of the interpenetrating cross-linked network and improves the stability of the network, while facilitating the smooth formation of the epoxy resin cross-linked network. Detailed Implementation

[0053] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0054] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0055] The method for preparing monomer A used in Example 1 below is as follows:

[0056] (1) Prepare monomer A by reacting p-acetoxystyrene, trioxymethylene and 2-aminoimidazole in a molar ratio of 1:1:2. Dissolve p-acetoxystyrene in methanol, then add trioxymethylene and 2-aminoimidazole, stir to dissolve, add concentrated hydrochloric acid accounting for 1% of the total weight of raw materials, and stop the reaction after reacting at 50°C for 12 h.

[0057] (2) The reaction solution was neutralized to neutral with sodium bicarbonate, the organic layer was washed with saturated brine, dried with anhydrous sodium sulfate, and concentrated by vacuum filtration to obtain an oily product, namely monomer A containing both structural formula 1 and structural formula 2. SiO2 column chromatography was used. When the eluent gradient was changed to petroleum ether: ethyl acetate = 10-15:1, structural formula 1 was obtained. When the eluent gradient was changed to petroleum ether: ethyl acetate = 30-50:1, structural formula 2 was obtained. The total yield of monomer A with both structural formulas was 73%.

[0058] In the above preparation method, the molar ratio of structural formula 1 and structural formula 2 obtained by separation is 0.694:0.306.

[0059] Using the same method, only the reaction temperature of the raw materials was increased from 50℃ to 60℃, and the reaction was stopped after 7 hours. The treatment method in step (2) was also the same. The molar ratio of structural formula 1 and structural formula 2 was 0.931:0.069, and the total yield of the two structural formula monomers A was 76%.

[0060] Example 1

[0061] This embodiment relates to the preparation of a first coating. The first component forming the first coating includes 80-100 parts epoxy resin, 5-10 parts monomer containing at least two thiol groups, 5-10 parts monomer A, 10-20 parts diluent, 40-50 parts filler, 2-4 parts defoamer, 2-4 parts leveling agent, 2-5 parts dispersant, 8-15 parts ethylenediamine, 1 part photoinitiator, and 10-25 parts solvent. Monomer A has the following structural formula 1 and / or 2:

[0062]

[0063] The above-mentioned components, epoxy resin, monomers containing at least two thiol groups, monomer A, diluent, filler, defoamer, leveling agent, dispersant, ethylenediamine, photoinitiator, and solvent are mixed and coated on the surface of a polished steel plate (50*120*0.5mm). The first coating 1#-6# and the comparative first coating D1#-D3# are prepared by curing in three stages. The coating thickness is 600μm. The first stage is cured at 40℃ for 2h, the second stage is cured under ultraviolet light for 40min, and the third stage is cured at 40℃ for 5h. In Table 1, each coating uses 3 parts BYK-093 as a defoamer, 3 parts BYK-323 as a leveling agent, and 4 parts BYK-190 as a dispersant. The diluent is a mixture of ethanol and acetone in a 1:1 weight ratio. The solvent is a mixture of ethanol and tetrahydrofuran in a 2:1 weight ratio. The filler is a mixture of silica and hydroxyapatite in a 1:1 weight ratio with a particle size of 1000 mesh. 1 part benzoyl dimethyl ether is used as a photoinitiator. The first coating, D3#, does not contain an initiator. Other differences are shown in Table 1.

[0064] Table 1

[0065]

[0066]

[0067] First coatings 7#-9# were prepared using different curing methods according to the component ratio of first coating 3# in Table 1. The specific differences are shown in Table 2.

[0068] Table 2

[0069]

[0070] Test Example 1

[0071] The alkali resistance, acid resistance, and carbon dioxide resistance of the first coatings 1#-9# and the comparative first coatings D1#-D3# prepared in Example 1 were tested. The test methods are as follows:

[0072] Alkali resistance: The coated steel plate was immersed in a 5% NaOH solution at 80℃ for 720 hours. After immersion, the surface morphology of the first coating was observed. The steel plate was then wiped clean and dried. The weight after drying was obtained, and the weight loss rate of the steel plate was calculated. The weight loss rate = [(original weight of steel plate - weight of dried steel plate) / original weight of steel plate] * 100%. The results are shown in Table 3.

[0073] Acid resistance: The coated steel plate was immersed in a 5% H2SO4 solution at 80°C for 720 hours. After immersion, the surface morphology of the first coating was observed, and the weight loss rate of the steel plate was calculated. The results are shown in Table 3.

[0074] Carbon dioxide resistance: The coated steel plate was placed in a saturated carbon dioxide aqueous solution and immersed at 80°C for 720 hours. After that, it was taken out and the surface morphology of the first coating was observed. The weight loss rate of the steel plate was also calculated. The results are shown in Table 3.

[0075] Table 3

[0076]

[0077]

[0078] Test Example 2

[0079] The wear resistance and weather resistance of the first coatings 1#-9# and the comparative first coatings D1#-D3# prepared in Example 1 were tested using the following methods:

[0080] abrasion resistance

[0081] The wear performance of the coating was tested using an abrasion tester. The test conditions were as follows: the coating surface was polished with a grinding wheel at a frequency of 500 times / min, with a load of 500g and a wear time of 120min. The grinding wheel was replaced every 10min. After the steel plate was worn, it was rinsed, wiped clean, and dried. The weight of the dried steel plate was obtained, and the weight loss rate of the steel plate was calculated. The weight loss rate is calculated as [(original weight of steel plate - weight of dried steel plate) / original weight of steel plate] * 100%. The results are shown in Table 4 below.

[0082] Weather resistance

[0083] The test was conducted in accordance with IEC 61646:2008. The UVB (280–320 nm) energy in the metal halide lamp used in the test accounted for 3%–10% of the total energy, and the lamp irradiance was 180 W / m². 2 The test samples were prepared into experimental specimens of a specific size and were placed in a QUV aging test chamber for ultraviolet irradiation. The total irradiation energy of the instrument was 180 kWh / m². 2 The coating surface was tested under light. The test conditions were: QUV-B, light exposure at 60℃, condensation at 10℃, with 8 hours of light exposure and 4 hours of condensation every 4 hours, for a total of 1600 hours. After the sample aging was completed, the IV value of the test sample after QUV aging was measured. The test results are shown in Table 4.

[0084] Table 4

[0085] First coating #1 0.4 0.14 First coating #2 0.4 0.13 First coating #3 0.3 0.12 First coating #4 1.1 0.36 First coating #5 0.7 0.28 First coating #6 0.6 0.21 First coating #7 0.3 0.13 First coating #8 1.5 0.49 First coating #9 1.4 0.40 Comparison with the first coating D1# 2.3 0.75 Comparison with the first coating D2# 1.9 0.63 Comparison with the first coating D3# 2.7 0.91

[0086] Example 2

[0087] This embodiment relates to a production process for an anti-corrosion and wear-resistant pipe coating, including the following steps:

[0088] (1) The above epoxy resin, monomer containing at least two mercapto groups, monomer A, diluent, filler, defoamer, leveling agent, dispersant, ethylenediamine, photoinitiator and solvent are mixed, coated on the pipe wall and cured to obtain the first coating.

[0089] (2) Mix the above-mentioned polyethylene resin, polyvinyl butyral, toughening agent, filler and leveling agent, extrude and granulate, grind and then spray on the first coating to form the second coating, thus obtaining the anti-corrosion and wear-resistant pipe coating.

[0090] The differences in raw materials used for the second coating, namely pipe coatings 1#-9# and comparative pipe coatings D1#-D2#, prepared according to the above process are as follows:

[0091] Pipe Coating #1

[0092] The second coating was prepared based on the first coating 3#. 80 parts of polyethylene resin, 10 parts of polyvinyl butyral, 20 parts of toughening agent, 30 parts of filler and 3 parts of leveling agent were mixed, extruded and granulated at 200℃, ground and then sprayed on the first coating to form the second coating. The thickness of the second coating was 300μm, which is the pipe coating 1#.

[0093] Pipe Coating #2

[0094] Based on the first coating 3#, a second coating is prepared by mixing 120 parts of polyethylene resin, 15 parts of polyvinyl butyral, 30 parts of toughening agent, 50 parts of filler and 8 parts of leveling agent, extruding and granulating at 240℃, grinding and spraying onto the first coating to form the second coating. The thickness of the second coating is 800μm, which is the pipe coating 2#.

[0095] Pipe Coating #3

[0096] The difference between this pipe coating #3 and pipe coating #1 is that it also includes a wear-resistant layer. This wear-resistant layer is formed by a melting spraying process using wear-resistant material, which accounts for 30% of the total weight of the second component. The thickness of the wear-resistant layer is 100μm. This wear-resistant material is composed of silicon carbide and diamond in a weight ratio of 1:1, wherein the particle size of silicon carbide is 10μm and the particle size of diamond is 3μm. The rest is the same as that of pipe coating #1, thus obtaining pipe coating #3.

[0097] Pipe coating #4

[0098] The difference between this pipe coating #4 and pipe coating #1 is that it also includes a wear-resistant layer. This wear-resistant layer is formed by a melting spraying process using wear-resistant material, which accounts for 50% of the total weight of the second component. The thickness of the wear-resistant layer is 300μm. This wear-resistant material is composed of silicon carbide and diamond in a weight ratio of 1:2, wherein the particle size of silicon carbide is 5μm and the particle size of diamond is 1μm. The rest is the same as that of pipe coating #1, thus obtaining pipe coating #4.

[0099] Pipe coating #5

[0100] The difference between pipe coating #5 and pipe coating #3 is that aluminum oxide is used instead of silicon carbide. The rest is the same as pipe coating #3, thus obtaining pipe coating #5.

[0101] Pipe Coating #6

[0102] The difference between this pipe coating #6 and pipe coating #3 is that the particle size of both silicon carbide and diamond is 3μm. The rest is the same as pipe coating #3, thus obtaining pipe coating #6.

[0103] Pipe coating #7

[0104] The difference between this pipe coating #7 and pipe coating #3 is that the wear-resistant material is modified with polyvinyl butyral. The wear-resistant material is placed in a polyvinyl butyral solution and kept at 50-70℃ for 2-4 hours. After filtration and drying, the modified wear-resistant material is obtained. The rest is the same as pipe coating #3, thus obtaining pipe coating #7.

[0105] Pipe coating #8

[0106] The difference between pipe coating #8 and pipe coating #7 is that it also includes a third coating, which is obtained by coating 20 parts of cashew phenol benzoxazine resin onto the surface of the wear-resistant layer and curing it at 100°C for 8 hours. The thickness of the third coating is 40 μm, and the rest is the same as pipe coating #7, thus obtaining pipe coating #8.

[0107] Pipe coating #9

[0108] The difference between pipe coating #9 and pipe coating #7 is that it also includes a third coating, which is obtained by coating 50 parts of cashew phenol benzoxazine resin onto the surface of the wear-resistant layer and curing it at 85°C for 12 hours. The thickness of the third coating is 100 μm, and the rest is the same as pipe coating #7, thus obtaining pipe coating #9.

[0109] Comparison of pipe coating D1#

[0110] The difference between this comparative pipe coating D1# and pipe coating 1# is that it does not contain polyvinyl butyral, while the rest is the same as pipe coating 1#, thus obtaining comparative pipe coating D1#.

[0111] Comparison of pipe coating D2#

[0112] The difference between this comparative pipe coating D2# and pipe coating 1# is that polyvinyl alcohol is used instead of polyvinyl butyral, while the rest is the same as pipe coating 1#, thus obtaining comparative pipe coating D2#.

[0113] The preparation method of the cashew phenol-based benzoxazine resin used in the above-mentioned pipe coatings #8 and #9 is as follows:

[0114] (1) By weight, add 6 parts of cashew phenol, 10 parts of mercaptoglycerol and 0.16 parts of Irgacure-184 to the reaction flask and react under ultraviolet light for 36 h to synthesize hydroxy cashew phenol with hydroxyl groups in the side chain.

[0115] (2) By weight, add 5 parts of hydroxy cashew phenol with hydroxyl group in side chain prepared in step (1), 2.5 parts of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 1 part of formaldehyde to the reaction flask and react in an oil bath at 60°C for 14 h to synthesize cashew phenol benzoxazine monomer with hydroxyl group in side chain;

[0116] (3) By weight, 2 parts of the cashew phenol benzoxazine monomer with side chain containing hydroxyl groups prepared in step (2) and 1 part of phenyl diboronic acid are mixed and reacted at 0°C for 24 hours to obtain the cashew phenol benzoxazine resin.

[0117] Test Example 3

[0118] The alkali resistance, acid resistance, and carbon dioxide resistance of the pipe coatings 1#-9# prepared in Example 2 and the comparative pipe coatings D1#-D2# were tested. The test methods are as follows:

[0119] Alkali resistance: The coated steel plate was immersed in a 5% NaOH solution at 80℃ for 720 hours. After immersion, the surface morphology of the first coating was observed. The steel plate was then wiped clean and dried. The weight after drying was obtained, and the weight loss rate of the steel plate was calculated. The weight loss rate = [(original weight of steel plate - weight of dried steel plate) / original weight of steel plate] * 100%. The results are shown in Table 5.

[0120] Acid resistance: The coated steel plate was immersed in a 5% H2SO4 solution at 80°C for 720 hours. After immersion, the surface morphology of the first coating was observed, and the weight loss rate of the steel plate was calculated. The results are shown in Table 5.

[0121] Carbon dioxide resistance: The coated steel plate was placed in a saturated carbon dioxide aqueous solution and immersed at 80°C for 720 hours. After that, it was taken out and the surface morphology of the first coating was observed. The weight loss rate of the steel plate was also calculated. The results are shown in Table 5.

[0122] Table 5

[0123]

[0124]

[0125] Test Example 4

[0126] The wear resistance, weather resistance, and scratch resistance of the pipe coatings 1#-9# prepared in Example 2 and the comparative pipe coatings D1#-D2# were tested. The test methods are as follows:

[0127] abrasion resistance

[0128] The wear performance of the coating was tested using an abrasion tester. The test conditions were as follows: the coating surface was polished with a grinding wheel at a frequency of 500 times / min, with a load of 500g and a wear time of 120min. The grinding wheel was replaced every 10min. After the steel plate was worn, it was rinsed, wiped clean, and dried. The weight of the dried steel plate was obtained, and the weight loss rate of the steel plate was calculated. The weight loss rate is calculated as [(original weight of steel plate - weight of dried steel plate) / original weight of steel plate] * 100%. The results are shown in Table 6 below.

[0129] Weather resistance

[0130] The test was conducted in accordance with IEC 61646:2008. The UVB (280–320 nm) energy in the metal halide lamp used in the test accounted for 3%–10% of the total energy, and the lamp irradiance was 180 W / m². 2 The test samples were prepared into experimental specimens of a specific size and were placed in a QUV aging test chamber for ultraviolet irradiation. The total irradiation energy of the instrument was 180 kWh / m². 2 The coating surface was tested under light. The test conditions were: QUV-B, light exposure at 60℃, condensate at 10℃, with 8 hours of light exposure followed by 4 hours of condensation, for a total of 1600 hours. After the sample aging was completed, the IV value of the test sample after QUV aging was measured. The test results are shown in Table 6.

[0131] Scratch-resistant

[0132] The scratch resistance of the coating was tested using a scratch test. The coating was fixed so that it coincided with the center of the pendulum of the friction testing machine. 0000# steel wool was attached to the center of the mold. The total load was 100g, and the friction area was 2cm × 2cm. The sample was rubbed 100 times at a speed of 30 times / min. After testing, the sample was washed and dried. The surface of the sample was observed. If there were fewer than 5 scratches less than 5mm in length, it was classified as Grade A; if there were more than 5 but fewer than 10 scratches less than 5mm in length, it was classified as Grade B. If there are no scratches longer than 5mm, it is classified as Grade B; if there are more than 5 but less than 10 scratches shorter than 5mm on the surface, and less than 2 scratches longer than 10mm on the surface, it is classified as Grade C; if there are more than 10 scratches shorter than 5mm on the surface, and less than 2 scratches longer than 10mm on the surface, it is classified as Grade D; if there are more than 10 scratches shorter than 5mm on the surface, and more than 2 scratches longer than 10mm on the surface, it is classified as Grade E.

[0133] Table 6

[0134] Pipe Coating #1 1.8 0.57 Class C Pipe Coating #2 2.0 0.64 Class C Pipe Coating #3 0.8 0.27 Grade A Pipe coating #4 0.9 0.34 Grade B Pipe coating #5 1.4 0.48 Class C Pipe Coating #6 1.2 0.41 Grade B Pipe coating #7 0.3 0.13 Grade A Pipe coating #8 0.3 0.12 Grade B Pipe coating #9 0.2 0.10 Grade B Comparison of pipe coating D1# 2.9 1.23 Class E Comparison of pipe coating D2# 2.5 0.81 Class D

[0135] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A corrosion-resistant and wear-resistant pipe coating, characterized in that, The coating comprises a first coating formed by curing a first component on the pipe wall and a second coating formed by curing a second component on the outside of the first coating; By weight, the first component comprises 80-100 parts epoxy resin, 5-10 parts monomer containing at least two thiol groups, 5-10 parts monomer A, 10-20 parts diluent, 40-50 parts filler, 2-4 parts defoamer, 2-4 parts leveling agent, 2-5 parts dispersant, 8-15 parts ethylenediamine, 1 part photoinitiator, and 10-25 parts solvent, wherein monomer A has the following structural formula 1 and / or 2: Structural Formula 1 Structural Formula 2 The second component comprises 80-120 parts polyethylene resin, 10-15 parts polyvinyl butyral, 20-30 parts toughening agent, 30-50 parts filler and 3-8 parts leveling agent; The monomer containing at least two thiol groups is selected from at least one of 1,4-dimercapto-2,3-butanediol, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, di(mercaptoacetic acid)-1,4-butanediol ester, and ethylene glycol dimercaptoacetate.

2. The anti-corrosion and wear-resistant pipe coating according to claim 1, characterized in that, The monomer containing at least two thiol groups is selected from pentaerythritol tetrakis(3-mercaptopropionic acid) and di(mercaptoacetic acid)-1,4-butanediol.

3. The anti-corrosion and wear-resistant pipe coating according to claim 2, characterized in that, The molar ratio of the tetra(3-mercaptopropionic acid) pentaerythritol ester and di(mercaptoacetic acid)-1,4-butanediol ester is 1:

4.

4. The anti-corrosion and wear-resistant pipe coating according to claim 1, characterized in that, The monomer A is a mixture of structural formulas 1 and 2, with a molar ratio of 7:3 between structural formulas 1 and 2.

5. The anti-corrosion and wear-resistant pipe coating according to claim 1, characterized in that, The monomer A was prepared by reacting p-acetoxystyrene, formaldehyde compounds and 2-aminoimidazole in an acidic catalyst at a molar ratio of 1:(1-3):(1-2).

6. The anti-corrosion and wear-resistant pipe coating according to claim 5, characterized in that, The preparation temperature of monomer A from p-acetoxystyrene, formaldehyde compounds, and 2-aminoimidazole is 50-60℃, and the time is 7-12h.

7. The anti-corrosion and wear-resistant pipe coating according to claim 5, characterized in that, The formaldehyde compounds are selected from at least one of formaldehyde, trioxymethylene, and paraoxymethylene.

8. The production process of the anti-corrosion and wear-resistant pipe coating according to any one of claims 1-7, characterized in that, Includes the following steps: (1) The first coating is obtained by mixing the above epoxy resin, monomer containing at least two mercapto groups, monomer A, diluent, filler, defoamer, leveling agent, dispersant, ethylenediamine, photoinitiator and solvent, coating it on the pipe wall and curing it. (2) Mix the above-mentioned polyethylene resin, polyvinyl butyral, toughening agent, filler and leveling agent, extrude and granulate, grind and then spray on the first coating to form the second coating, thus obtaining the anti-corrosion and wear-resistant pipe coating.

9. The production process according to claim 8, characterized in that, In step (1), the curing process is divided into three stages: First stage: Curing at 40℃-60℃ for 1-2 hours; Second stage: Curing under ultraviolet light for 10-40 minutes; Third stage: Curing at 40℃-60℃ for more than 3 hours.

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