Water-based conductive anticorrosive paint with temperature-resistant and hydrophobic characteristics and preparation method of water-based conductive anticorrosive paint

Abstract

The invention discloses a water-based conductive anticorrosive paint with temperature-resistant and hydrophobic characteristics and a preparation method thereof, and belongs to the technical field of paints. Comprising the following components in parts by mass: 40-60 parts of waterborne epoxy resin; 10 to 30 parts of water-based polytetrafluoroethylene; 2.5 to 15 parts of a polyaniline grafted nitrogen doped carbon nano tube; 1-8 parts of a corrosion inhibitor; 0.05 to 0.2 part of a silane coupling agent; 0.5 to 1.5 parts of a defoaming agent; 10-30 parts of a curing agent; and 20 to 30 parts of deionized water. The water-based temperature-resistant hydrophobic conductive anticorrosive paint provided by the invention has the characteristics of high corrosion resistance, high conductivity, high hydrophobicity, high temperature resistance, high adhesive force and the like, and can be applied to the fields of petrochemical equipment, electronic components, automobile industry and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a water-based conductive anti-corrosion coating with temperature-resistant and hydrophobic properties and a preparation method thereof. Background Art

[0002] Most of the raw materials and products required by the petrochemical industry are flammable and corrosive. In order to avoid fire accidents caused by static sparks and safety problems caused by corrosion, the surface of the metal equipment used needs to be coated with conductive anti-corrosion coatings. Traditional anti-corrosion conductive coatings use solvent-based anti-corrosion conductive coatings, which will volatilize a large amount of volatile organic compounds during the construction process, which is easy to cause environmental pollution and human harm, leading to safety accidents such as fire and explosion, and does not meet the requirements of sustainable development. In order to meet the green, environmentally friendly, safe and reliable application needs of the coatings industry, the development of water-based conductive anti-corrosion coatings has become a mainstream development trend.

[0003] In the production process of petrochemical products, high temperature production conditions are often required, which requires that the conductive anti-corrosion coating used in its production equipment also needs to have temperature resistance. Most of the existing water-based conductive anti-corrosion coatings use water-based epoxy resin coatings. For example, CN103756514B discloses a water-based two-component light-colored tank internal static conductive anti-corrosion coating, which is composed of tap water, water-based epoxy emulsion, water-based epoxy curing agent, anti-rust pigment, white pigment, white filler, light-colored conductive filler, anti-settling agent, wetting dispersant A, wetting dispersant B, film-forming aid, defoamer, leveling agent, anti-flash rust agent, thickener. CN115124905A discloses a water-based epoxy conductive anti-corrosion coating with graphene conductive powder as a conductive agent, which is composed of A component and B component mixed in a mass ratio of 5:1, wherein A component includes water-based epoxy resin, substrate wetting agent, first defoamer, anti-flash rust agent, ethylene glycol butyl ether and graphene conductive powder aqueous slurry. Component B includes a water-based epoxy curing agent and water. However, the temperature resistance limit of the water-based epoxy resin coating used in the above invention is about 120°C, and the long-term use temperature generally does not exceed 80°C, which greatly limits its use scenarios in high-temperature equipment in the petrochemical industry. CN116042050B discloses a water-based conductive anti-corrosion coating, including a primer and a topcoat applied to the surface of the primer, wherein the topcoat is composed of component A and component B, wherein component A includes a water-based epoxy resin, a conductive hydrogel, a first filler, a flame retardant liquid, an aqueous dispersant, a defoamer, an active monomer, a first cosolvent, an amine neutralizer, and functionalized graphene, and component B is a water-based epoxy curing agent. The primer is composed of component C and component D, wherein component C includes a water-based epoxy resin, a second filler, a water-based dispersant, a water-based defoamer, an adhesion promoter, a water-based thickener, a water-based anti-flash rust agent, a second cosolvent, an amine neutralizer, functionalized graphene, and deionized water, and component D includes a water-based epoxy curing agent and a third cosolvent. Although the temperature resistance limit of the conductive anti-corrosion coating can be increased to 200°C by adopting the above invention scheme, there are still problems such as complex coating components, cumbersome preparation process and large coating thickness. In addition, the conductive anti-corrosion coating prepared by water-based coating generally has a high water absorption rate, which affects its long-term use effect, so it is also necessary to improve the water resistance and hydrophobicity of the coating. Summary of the invention

[0004] Purpose of the invention: In order to solve the problems of poor temperature resistance, high water absorption, poor long-term corrosion resistance, etc. in the existing water-based conductive anti-corrosion coating technology, the present invention proposes a water-based conductive anti-corrosion coating with temperature-resistant and hydrophobic properties and a preparation method thereof. The coating has the characteristics of high temperature resistance, high hydrophobicity, high conductivity, high corrosion resistance, high hardness, high adhesion, etc., and can be applied to petrochemical equipment, electronic components, automotive industry and other fields.

[0005] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is: A water-based conductive anticorrosive coating with temperature-resistant and hydrophobic properties, comprising the following components in proportion by mass: 40-60 parts of water-based epoxy resin, 10-30 parts of water-based polytetrafluoroethylene emulsion, 2.5-15 parts of polyaniline-grafted nitrogen-doped carbon nanotubes, 1-8 parts of corrosion inhibitor, 0.05-0.2 parts of silane coupling agent, 0.5-1.5 parts of defoaming agent, 10-30 parts of curing agent, and 20-30 parts of deionized water.

[0006] Preferably, the polyaniline-grafted nitrogen-doped carbon nanotubes are corrosion inhibitor@polyaniline-grafted nitrogen-doped carbon nanotubes.

[0007] Preferably, the corrosion inhibitor is one or more of 8-hydroxyquinoline, benzotriazole, and 2-mercaptobenzothiazole.

[0008] A method for preparing a water-based conductive anticorrosive coating having temperature-resistant and hydrophobic properties comprises the following steps: Step S1: preparing a polyaniline grafted nitrogen-doped carbon nanotube composite material.

[0009] Step S2: preparing a corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler according to the polyaniline grafted nitrogen-doped carbon nanotube composite material prepared in step 1.

[0010] Step S3: preparing a water-based epoxy resin / polytetrafluoroethylene mixed emulsion.

[0011] Step S4: preparing a water-based temperature-resistant hydrophobic conductive anti-corrosion coating based on the corrosion inhibitor @polyaniline grafted nitrogen-doped carbon nanotube filler and the water-based epoxy resin / polytetrafluoroethylene mixed emulsion.

[0012] Preferably: the method for preparing a polyaniline grafted nitrogen-doped carbon nanotube composite material in step S1: add nitrogen-doped carbon nanotubes and aniline monomers in a mass ratio of 1 / 5-1 / 20 to a 1 mol / L hydrochloric acid solution, and ultrasonically vibrate for 1-2 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. Add 0.015 mmol / L ammonium persulfate solution dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, control the molar ratio of the amount of ammonium persulfate added to aniline to be 1.0-1.3, and react for 2-5 h under ice bath stirring. Filter the reaction solution, wash with ethanol and deionized water in turn, and dry to obtain a polyaniline grafted nitrogen-doped carbon nanotube composite material.

[0013] Preferably: the method for preparing the corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler in step S2: adding 2.5-15 parts of polyaniline grafted nitrogen-doped carbon nanotube composite material and 1-8 parts of corrosion inhibitor to anhydrous ethanol in a mass ratio, ultrasonically adsorbing for 3-5 h under vacuum conditions, followed by centrifugal washing and vacuum drying to obtain the corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler.

[0014] Preferably, in step S3, a method for preparing a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion is as follows: 40-60 parts of a waterborne epoxy resin, 10-30 parts of a waterborne polytetrafluoroethylene and 0.05-0.2 parts of a silane coupling agent are mixed and stirred in a mass ratio to obtain a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0015] Preferably: the method for preparing a water-based heat-resistant hydrophobic conductive anti-corrosion coating in step S4: 5-20 parts of corrosion inhibitor @polyaniline grafted nitrogen-doped carbon nanotube filler, 0.5-1.5 parts of defoaming agent and 10-30 parts of curing agent are sequentially added to 40-80 parts of water-based epoxy resin / polytetrafluoroethylene mixed emulsion and stirred and mixed evenly to obtain a water-based heat-resistant hydrophobic conductive anti-corrosion coating.

[0016] Preferably, the nitrogen-doped carbon nanotubes used in step S1 have a nitrogen content of 5-8 wt%, a length of 0.5-1 μm, a diameter of 15-20 nm, and an inner diameter of 8-12 nm. The mass percentage of the corrosion inhibitor in the corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler used in step S4 is 10-15%.

[0017] Preferably, the silane coupling agent used in step S3 is 3-glycidyloxypropyltrimethoxysilane KH-550. The defoaming agent used in step S4 is JT-20221. The curing agent used in step S4 is polyamide curing agent.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts polyaniline chains to grow directly from N-doped sites of carbon nanotubes to form a polyaniline grafted nitrogen-doped carbon nanotube composite material, synergistically improves the electrical conductivity and anti-corrosion performance of carbon nanotubes, combines the use of corrosion inhibitors loaded in carbon nanotubes to prepare corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler composite materials as filler materials, and water-based polytetrafluoroethylene modified epoxy resin as film-forming matrix materials, thereby realizing the preparation of a water-based conductive anti-corrosion coating with high temperature resistance, high hydrophobicity, high conductivity, high corrosion resistance, high hardness, high adhesion and other characteristics.

[0019] Polytetrafluoroethylene emulsion with high chemical corrosion resistance, high hydrophobicity and high temperature resistance is introduced into the water-based epoxy resin matrix to improve the hydrophobicity, temperature resistance and corrosion resistance of the coating matrix material. Polyaniline grafted nitrogen-doped carbon nanotubes are used as conductive fillers and corrosion inhibitor carriers to achieve the preparation of green and environmentally friendly water-based coatings with integrated functions of high corrosion resistance, high hydrophobicity, high temperature resistance and high conductivity. DETAILED DESCRIPTION

[0020] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0021] Example 1 A method for preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating, comprising the following specific steps: Step S1: Preparation of polyaniline grafted nitrogen-doped carbon nanotube composite material Nitrogen-doped carbon nanotubes and aniline monomers with a mass ratio of 1 / 10 were added to a 1 mol / L hydrochloric acid solution and ultrasonically vibrated for 2 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. A 0.015 mmol / L ammonium persulfate solution was added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, and the molar ratio of the amount of ammonium persulfate added to aniline was controlled to be 1.2. The reaction was stirred in an ice bath for 4 h. The reaction solution was filtered, washed with ethanol and deionized water in turn, and vacuum dried at 60°C for 24 h to obtain a polyaniline-grafted nitrogen-doped carbon nanotube composite material.

[0022] Step S2: Preparation of 8-hydroxyquinoline corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler 10 parts of polyaniline grafted nitrogen-doped carbon nanotube composites and 5 parts of 8-hydroxyquinoline corrosion inhibitor were added to 30 parts of anhydrous ethanol according to the mass ratio, and ultrasonic adsorption was treated for 3 h under vacuum conditions. The precipitate was then centrifuged and washed to obtain a precipitate, which was vacuum dried at 80 °C for 24 h to obtain 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler.

[0023] Step S3: Preparation of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion 50 parts of waterborne epoxy resin, 15 parts of waterborne polytetrafluoroethylene and 0.1 parts of silane coupling agent were mixed according to the mass ratio, and stirred at a speed of 1000 r / min for 2 h to prepare a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0024] Step S4: Preparation of water-based temperature-resistant hydrophobic conductive anticorrosive coating 10 parts of 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler, 1 part of defoamer and 25 parts of curing agent were added sequentially into 64 parts of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion and stirred at 3000 r / min for 3 hours to prepare a waterborne temperature-resistant hydrophobic conductive anti-corrosion coating.

[0025] Example 2 A method for preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating, comprising the following specific steps: Step S1: Preparation of polyaniline grafted nitrogen-doped carbon nanotube composite material Nitrogen-doped carbon nanotubes and aniline monomers with a mass ratio of 1 / 10 were added to a 1 mol / L hydrochloric acid solution and ultrasonically vibrated for 2 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. A 0.015 mmol / L ammonium persulfate solution was added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, and the molar ratio of the amount of ammonium persulfate added to aniline was controlled to be 1.2. The reaction was stirred in an ice bath for 4 h. The reaction solution was filtered, washed with ethanol and deionized water in turn, and vacuum dried at 60°C for 24 h to obtain a polyaniline-grafted nitrogen-doped carbon nanotube composite material.

[0026] Step S2: Preparation of 8-hydroxyquinoline corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler 10 parts of polyaniline grafted nitrogen-doped carbon nanotube composites and 5 parts of 8-hydroxyquinoline corrosion inhibitor were added to 30 parts of anhydrous ethanol according to the mass ratio, and ultrasonic adsorption was treated for 3 h under vacuum conditions. The precipitate was then centrifuged and washed to obtain a precipitate, which was vacuum dried at 80 °C for 24 h to obtain 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler.

[0027] Step S3: Preparation of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion 60 parts of waterborne epoxy resin, 15 parts of waterborne polytetrafluoroethylene and 0.1 parts of silane coupling agent were mixed according to the mass ratio, and stirred at a speed of 1000 r / min for 2 h to prepare a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0028] Step S4: Preparation of water-based temperature-resistant hydrophobic conductive anticorrosive coating 10 parts of 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler, 1 part of defoamer and 25 parts of curing agent were added sequentially into 64 parts of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion and stirred at 3000 r / min for 3 hours to prepare a waterborne temperature-resistant hydrophobic conductive anti-corrosion coating.

[0029] Example 3 A method for preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating, comprising the following specific steps: Step S1: Preparation of polyaniline grafted nitrogen-doped carbon nanotube composite material Nitrogen-doped carbon nanotubes and aniline monomers with a mass ratio of 1 / 10 were added to a 1 mol / L hydrochloric acid solution and ultrasonically vibrated for 2 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. A 0.015 mmol / L ammonium persulfate solution was added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, and the molar ratio of the amount of ammonium persulfate added to aniline was controlled to be 1.2. The reaction was stirred in an ice bath for 4 h. The reaction solution was filtered, washed with ethanol and deionized water in turn, and vacuum dried at 60°C for 24 h to obtain a polyaniline-grafted nitrogen-doped carbon nanotube composite material.

[0030] Step S2: Preparation of 8-hydroxyquinoline corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler 10 parts of polyaniline grafted nitrogen-doped carbon nanotube composites and 5 parts of 8-hydroxyquinoline corrosion inhibitor were added to 30 parts of anhydrous ethanol according to the mass ratio, and ultrasonic adsorption was treated for 3 h under vacuum conditions. The precipitate was then centrifuged and washed to obtain a precipitate, which was vacuum dried at 80 °C for 24 h to obtain 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler.

[0031] Step S3: Preparation of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion 44 parts of waterborne epoxy resin, 22 parts of waterborne polytetrafluoroethylene and 0.1 parts of silane coupling agent were mixed according to the mass ratio, and stirred at a speed of 1000 r / min for 2 h to prepare a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0032] Step S4: Preparation of water-based temperature-resistant hydrophobic conductive anticorrosive coating 10 parts of 8-hydroxyquinoline corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler, 1 part of defoamer and 25 parts of curing agent were added sequentially into 64 parts of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion and stirred at 3000 r / min for 3 hours to prepare a waterborne temperature-resistant hydrophobic conductive anti-corrosion coating.

[0033] Example 4 A method for preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating, comprising the following specific steps: Step S1: Preparation of polyaniline grafted nitrogen-doped carbon nanotube composite material Nitrogen-doped carbon nanotubes and aniline monomers with a mass ratio of 1 / 20 were added to a 1 mol / L hydrochloric acid solution and ultrasonically vibrated for 1 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. A 0.015 mmol / L ammonium persulfate solution was added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, and the molar ratio of the amount of ammonium persulfate added to aniline was controlled to be 1.3, and the reaction was carried out under ice bath stirring for 5 h. The reaction solution was filtered, washed with ethanol and deionized water in turn, and vacuum dried at 60°C for 24 h to obtain a polyaniline-grafted nitrogen-doped carbon nanotube composite material.

[0034] Step S2: Preparation of 2-mercaptobenzothiazole corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler 5 parts of polyaniline grafted nitrogen doped carbon nanotube composite material and 2.5 parts of 2-mercaptobenzothiazole corrosion inhibitor were added to 20 parts of anhydrous ethanol according to the mass ratio, and ultrasonic adsorption was carried out under vacuum conditions for 2 hours. The precipitate was then centrifuged and washed to obtain a precipitate, which was vacuum dried at 80°C for 24 hours to obtain 2-mercaptobenzothiazole corrosion inhibitor@polyaniline grafted nitrogen doped carbon nanotube filler after drying.

[0035] Step S3: Preparation of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion 50 parts of waterborne epoxy resin, 15 parts of waterborne polytetrafluoroethylene and 0.1 parts of silane coupling agent were mixed according to the mass ratio, and stirred at 1000 r / min for 2 hours to obtain a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0036] Step S4: Preparation of water-based temperature-resistant hydrophobic conductive anticorrosive coating 5 parts of 2-mercaptobenzothiazole corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler, 0.5 parts of defoamer and 20 parts of curing agent were added to 74.5 parts of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion in sequence and stirred at 2000 r / min for 5 hours to prepare a waterborne temperature-resistant hydrophobic conductive anticorrosive coating. Example 5 A method for preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating, comprising the following specific steps: Step S1: Preparation of polyaniline grafted nitrogen-doped carbon nanotube composite material Nitrogen-doped carbon nanotubes and aniline monomers with a mass ratio of 1 / 5 were added to a 1 mol / L hydrochloric acid solution and ultrasonically vibrated for 0.5 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion. A 0.015 mmol / L ammonium persulfate solution was added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, and the molar ratio of the amount of ammonium persulfate added to aniline was controlled to be 1.1. The reaction was stirred in an ice bath for 4 h. The reaction solution was filtered, washed with ethanol and deionized water in turn, and vacuum dried at 60°C for 24 h to obtain a polyaniline-grafted nitrogen-doped carbon nanotube composite material.

[0037] Step S2: Preparation of benzotriazole corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler 15 parts of polyaniline grafted nitrogen-doped carbon nanotube composite material and 7 parts of benzotriazole corrosion inhibitor were added to 40 parts of anhydrous ethanol according to the mass ratio, and ultrasonic adsorption was carried out for 3 hours under vacuum conditions, followed by centrifugal washing to obtain a precipitate, which was vacuum dried at 80°C for 24 hours to obtain benzotriazole corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler after drying. Step S3: Preparation of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion 50 parts of waterborne epoxy resin, 15 parts of waterborne polytetrafluoroethylene and 0.1 parts of silane coupling agent were mixed according to the mass ratio, and stirred at 1000 r / min for 2 hours to obtain a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion.

[0038] Step S4: Preparation of water-based temperature-resistant hydrophobic conductive anticorrosive coating 15 parts of benzotriazole corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler, 1 part of defoamer and 18 parts of curing agent were added in sequence into 66 parts of waterborne epoxy resin / polytetrafluoroethylene mixed emulsion and stirred at 2500r / min for 4 hours to prepare a waterborne temperature-resistant hydrophobic conductive anti-corrosion coating.

[0039] Comparative Example 1: No water-based polytetrafluoroethylene was added, the silane coupling agent was reduced to 0.05 parts, and the rest was the same as in Example 1.

[0040] Comparative Example 2: A polyaniline-grafted carbon nanotube composite material was prepared using non-nitrogen-doped acidified carbon nanotubes (length 0.5-1 μm, diameter 15-20 nm, inner diameter 8-12 nm), and the rest was the same as in Example 1.

[0041] Comparative Example 3: No corrosion inhibitor was added, and the rest was the same as Example 1.

[0042] Performance test: Prepare the coating according to the formula of the above examples 1-3 and comparative examples 1-3, apply the coating to the surface of carbon steel by spraying, cure at room temperature for 8 hours, and then cure at 60°C for 12 hours to obtain a heat-resistant hydrophobic conductive anti-corrosion coating sample. The heat resistance test method, contact angle test method, electrochemical AC impedance method, water absorption rate determination method, surface resistance test method, pencil hardness determination method, and cross-cutting test method were used to test the heat resistance, contact angle, corrosion resistance, water absorption rate, surface resistivity, hardness and adhesion performance of the heat-resistant hydrophobic conductive anti-corrosion coating sample. The specific test methods are as follows: The temperature resistance test is carried out according to GB / T 1735 testing standard.

[0043] Contact angle test: At room temperature, use a pipette to drop 5 μL of water onto the surface of the coating to be tested, and use a contact angle meter to test the static water contact angle of the coating to characterize the hydrophobic properties of the coating.

[0044] Corrosion resistance test: The corrosion resistance of the coating was tested by electrochemical impedance spectroscopy. The electrochemical impedance spectroscopy test used a three-electrode system, with the working electrode being the coating / carbon steel sheet, the auxiliary electrode being a platinum electrode, and the reference electrode being a saturated calomel electrode. The three electrodes were immersed in a 3.5 wt% NaCl aqueous solution, and the electrochemical impedance spectroscopy of the coating sample was tested at an open circuit potential at room temperature. The amplitude of the AC sinusoidal signal was 5 mV, and the measurement frequency range was 10 mHz-100 kHz.

[0045] The surface resistivity test is carried out according to GB / T 1410 testing standard.

[0046] The water absorption test is carried out according to the HG / T3344 testing standard.

[0047] The hardness test is carried out according to GB / T 6739 testing standard.

[0048] The adhesion test is carried out according to GB / T 9286 testing standard.

[0049] The specific performance test results are shown in Table 1. Comparing the coating samples of Example 1 and Comparative Example 1, the epoxy resin base film in Comparative Example 1 has a contact angle of 52° and a temperature resistance of 120°C. After the hydrophobic and temperature-resistant polytetrafluoroethylene material is introduced in Example 1, the contact angle of the coating is significantly increased to 119°, and the temperature resistance is increased to 200°C. At the same time, the introduction of polytetrafluoroethylene material will also improve the corrosion resistance, water absorption, hardness and adhesion of the coating material. Comparing the performance of the coating samples of Example 1 and Comparative Example 2, it is illustrated that nitrogen doping improves the preparation of highly conductive polyaniline grafted carbon nanotube composite materials. Nitrogen doping can provide additional electron pairs while increasing the surface energy of carbon nanotubes, which is conducive to the growth of polyaniline chains on carbon nanotubes, thereby preparing a highly conductive polyaniline grafted nitrogen-doped carbon nanotube composite material with a high grafting rate and uniform dispersion. The highly conductive polyaniline grafted nitrogen-doped carbon nanotube composite material is added to the coating as a filler, which is easy to form a three-dimensional conductive and barrier network structure, thereby improving the conductivity and corrosion resistance of the coating. Comparing the samples of Example 1 and Example 3, since the corrosion inhibitor was not added to the sample of Example 3, its corrosion resistance was significantly reduced. Comparing Examples 1-3, due to the different ratios of water-based epoxy resin to water-based polytetrafluoroethylene, the coating samples differed in properties such as temperature resistance, contact angle, and adhesion. Compared with Example 2, the proportion of polytetrafluoroethylene in the sample of Example 1 increased, so its contact angle, temperature tolerance, EIS corrosion resistance, and adhesion were all improved, while the water absorption rate was reduced. However, for the sample of Example 3, due to the introduction of too much polytetrafluoroethylene, the film-forming property of the coating deteriorated. Although its contact angle increased, its hardness and adhesion both decreased, so its temperature tolerance decreased. For Examples 4 and 5, compared with the sample of Example 1, the polyaniline grafting rate in Example 4 was reduced, so the conductivity and hardness of the coating prepared therefrom were reduced. In Example 5, a large amount of polyaniline grafted structures easily agglomerated and poorly dispersed in the coating, so the conductivity, hardness and adhesion of the coating decreased.

[0050] Table 1 In summary, the water-based temperature-resistant hydrophobic conductive anti-corrosion coating prepared by the present invention has the advantages of high corrosion resistance, high conductivity, high hydrophobicity, high temperature resistance and high adhesion, and can be applied to petrochemical equipment, electronic components, automobile industry and other fields, and has good application prospects.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A water-based conductive anti-corrosion coating with temperature-resistant and hydrophobic properties, characterized in that: The invention comprises the following components in proportion by mass: 40-60 parts of waterborne epoxy resin; 10-30 parts of waterborne polytetrafluoroethylene emulsion; 2.5-15 parts of polyaniline grafted nitrogen-doped carbon nanotubes; 1-8 parts of corrosion inhibitor; 0.05-0.2 parts of silane coupling agent; 0.5-1.5 parts of defoaming agent; 10-30 parts of curing agent; and 20-30 parts of deionized water.

2. The water-based conductive anti-corrosion coating with temperature-resistant and hydrophobic properties according to claim 1, characterized in that: The polyaniline-grafted nitrogen-doped carbon nanotubes are corrosion inhibitor@polyaniline-grafted nitrogen-doped carbon nanotubes.

3. The water-based conductive anti-corrosion coating with temperature-resistant and hydrophobic properties according to claim 2, characterized in that: The corrosion inhibitor is one or more of 8-hydroxyquinoline, benzotriazole and 2-mercaptobenzothiazole.

4. A method for preparing a water-based conductive anticorrosive coating having temperature-resistant and hydrophobic properties as claimed in claim 1, characterized in that: The steps include: Step S1: preparing a polyaniline grafted nitrogen-doped carbon nanotube composite material; Step S2: preparing a corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler according to the polyaniline grafted nitrogen-doped carbon nanotube composite material prepared in step 1; Step S3: preparing a waterborne epoxy resin / polytetrafluoroethylene mixed emulsion; Step S4: preparing a water-based temperature-resistant hydrophobic conductive anticorrosive coating based on the corrosion inhibitor @polyaniline grafted nitrogen-doped carbon nanotube filler and the water-based epoxy resin / polytetrafluoroethylene mixed emulsion.

5. The preparation method according to claim 4, characterized in that: The method for preparing a polyaniline grafted nitrogen-doped carbon nanotube composite material in step S1 is as follows: nitrogen-doped carbon nanotubes and aniline monomers in a mass ratio of 1 / 5-1 / 20 are added to a 1 mol / L hydrochloric acid solution, and ultrasonically oscillated for 1-2 h to obtain a nitrogen-doped carbon nanotube / aniline dispersion; 0.015 mmol / L ammonium persulfate solution is added dropwise to the nitrogen-doped carbon nanotube / aniline dispersion, the molar ratio of the amount of ammonium persulfate added to aniline is controlled to be 1.0-1.3, and the reaction is carried out under ice bath stirring for 2-5 h; the reaction solution is filtered, washed with ethanol and deionized water in turn, and dried to obtain a polyaniline grafted nitrogen-doped carbon nanotube composite material.

6. The preparation method according to claim 5, characterized in that: The method for preparing the corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler in step S2 is as follows: 2.5-15 parts of polyaniline grafted nitrogen-doped carbon nanotube composite material and 1-8 parts of corrosion inhibitor are added to anhydrous ethanol in a mass ratio, and ultrasonic adsorption is performed for 3-5 hours under vacuum conditions, followed by centrifugal washing and vacuum drying to obtain the corrosion inhibitor @ polyaniline grafted nitrogen-doped carbon nanotube filler.

7. The preparation method according to claim 6, characterized in that: The method for preparing the water-based epoxy resin / polytetrafluoroethylene mixed emulsion in step S3 is as follows: 40-60 parts of water-based epoxy resin, 10-30 parts of water-based polytetrafluoroethylene and 0.05-0.2 parts of silane coupling agent are mixed and stirred according to the mass ratio to obtain the water-based epoxy resin / polytetrafluoroethylene mixed emulsion.

8. The preparation method according to claim 7, characterized in that: The method for preparing a water-based heat-resistant hydrophobic conductive anti-corrosion coating in step S4 is as follows: 5-20 parts of a corrosion inhibitor @polyaniline grafted nitrogen-doped carbon nanotube filler, 0.5-1.5 parts of a defoaming agent and 10-30 parts of a curing agent are sequentially added to 40-80 parts of a water-based epoxy resin / polytetrafluoroethylene mixed emulsion and stirred and mixed evenly to obtain a water-based heat-resistant hydrophobic conductive anti-corrosion coating.

9. The preparation method according to claim 8, characterized in that: The nitrogen-doped carbon nanotubes used in step S1 have a nitrogen content of 5-8 wt%, a length of 0.5-1 μm, a diameter of 15-20 nm, and an inner diameter of 8-12 nm; the mass percentage of the corrosion inhibitor in the corrosion inhibitor@polyaniline grafted nitrogen-doped carbon nanotube filler used in step S4 is 10-15%.

10. The preparation method according to claim 9, characterized in that: The silane coupling agent used in step S3 is 3-glycidyloxypropyltrimethoxysilane KH-550; the defoaming agent used in step S4 is JT-20221; and the curing agent used in step S4 is polyamide curing agent.

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