A modified polyurea-based conductive anti-corrosion coating, its preparation method and application

Abstract

The present invention discloses a modified polyurea-based conductive anticorrosive coating, its preparation method and application, belonging to the technical field of polymer materials. The modified polyurea-based conductive anticorrosive coating prepared by the present invention uses carbon black as the main conductive filler, polyaniline and AZO as auxiliary conductive fillers, and utilizes the amino groups carried by polyaniline and the amino functional groups introduced by modified AZO, which can be chemically grafted onto the polyurea main chain during the curing process, enabling the coating to have better conductive performance and adhesion, thereby improving the corrosion resistance of the coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a modified polyurea-based conductive anticorrosive coating, a preparation method thereof, and an application thereof. Background Art

[0002] In the field of anti-corrosion of metals and other materials, coatings are widely used to protect surfaces from corrosion and oxidation. Traditional anti-corrosive coatings use epoxy resins, polyurethanes, acrylic resins, alkyd resins, etc. as film-forming resins, especially epoxy resins with the largest consumption. However, the coatings of epoxy resin anti-corrosive coatings have deficiencies such as poor flexibility, poor aging resistance, and low resistance to heat and humidity, resulting in very brittle coatings that are prone to pores or cracks, thus losing their anti-corrosion performance.

[0003] The electrical conductivity of traditional conductive anti-corrosive coatings is achieved by adding a large amount of conductive fillers to the film-forming resin, and the anti-corrosion performance is solely achieved by relying on the anti-corrosion performance of the film-forming resin. The common conductive fillers and the film-forming resin are mainly in a physical mixing manner, and there are problems of incompatibility. Wetting agents, dispersants and other modifiers often need to be added. Therefore, as the addition amount increases, the mechanical properties will inevitably be affected.

[0004] Existing conductive coatings can be divided into two categories according to their composition and conduction mechanism: structural (also known as intrinsic) conductive coatings and composite (also known as additive or doped) conductive coatings. The conductive material of intrinsic conductive coatings is the polymer itself (such as conductive polymers like polyaniline, etc.); the conductive material of additive conductive coatings is the conductive substance added to the insulating polymer, and the polymer has conductive properties by utilizing the conductive effect of the conductive substance.

[0005] Polyaniline is a polymer material with conductive properties. Due to the conjugated structure and redox properties in its molecules, polyaniline can adjust its conductivity by doping or controlling its oxidation state. However, pure polyaniline has poor film-forming properties and brittle coatings. Therefore, it is added or compounded into the film-forming resin for application, resulting in limited conductive performance that can be provided. Therefore, it is usually used as antistatic or shielding effectiveness and is difficult to meet the use requirements of conductive anti-corrosive coatings for grounding grids; the coatings often have defects such as pinholes and breakages, which are prone to form corrosion cells with large cathodes and small anodes, causing pitting corrosion and accelerating local corrosion of the grounding grid. Summary of the Invention

[0006] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this part, the abstract of the specification and the title of the invention of this application to avoid obscuring the purpose of this part, the abstract of the specification and the title of the invention, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0007] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0008] Therefore, an object of the present invention is to overcome the deficiencies in the prior art and provide a preparation method of a modified polyurea-based conductive anti-corrosion coating.

[0009] To solve the above technical problems, the present invention provides the following technical solutions: A preparation method of a modified polyurea-based conductive anti-corrosion coating, including,

[0010] Preparing nano-polyaniline;

[0011] Preparing conductive aluminum-doped nano-AZO powder;

[0012] Wet modification of nano-AZO powder;

[0013] Stir the siloxane-modified polyaspartate resin, solvent, and dispersant evenly, add conductive carbon black, modified nano-AZO powder, and nano-polyaniline, disperse evenly, ball mill, add a leveling agent, anti-settling agent, defoaming agent, and solvent, stir evenly to obtain component A;

[0014] Mix the HDI trimer and the solvent evenly to obtain the curing agent component B;

[0015] Measure component A and component B according to an NCO index of 1.05, quickly mix them at room temperature, and stir evenly to obtain the modified polyurea-based conductive anti-corrosion coating.

[0016] As a preferred embodiment of the preparation method of the present invention, wherein: for the preparation of nano-polyaniline, the preparation method of nano-polyaniline is:

[0017] For the preparation of nano-polyaniline, the preparation method of nano-polyaniline is:

[0018] Dissolve aniline An in ethylene glycol EG containing hydrochloric acid, and stir evenly to obtain an An solution;

[0019] Dissolve ammonium persulfate APS in ethylene glycol EG, and dissolve and stir to obtain an APS solution;

[0020] Slowly drip the APS solution into the An solution, continuously stir during the dripping process, then stir for 24 h, centrifuge, wash the product twice with ethanol and distilled water respectively, and vacuum dry at 45 °C for 24 h to obtain conductive nano-polyaniline.

[0021] As a preferred embodiment of the preparation method of the present invention, wherein: the molar ratio of ammonium persulfate APS to aniline An is 1:1 to 1.1:1.

[0022] As a preferred embodiment of the preparation method of the present invention, wherein: for the preparation of conductive aluminum-doped nano-AZO powder, the preparation method of the conductive aluminum-doped nano-AZO powder is as follows:

[0023] Dissolve zinc chloride and aluminum chloride hexahydrate in ethylene glycol to prepare a mixed ethylene glycol solution of zinc chloride and aluminum chloride with a concentration of 1 mol / L. 2+ A mixed ethylene glycol solution of zinc chloride and aluminum chloride with a concentration of 1 mol / L.

[0024] Dissolve sodium hydroxide in ethylene glycol to prepare a sodium hydroxide ethylene glycol solution with a concentration of 2 mol / L.

[0025] Quickly add the mixed ethylene glycol solution of zinc chloride and aluminum chloride to a quantitative sodium hydroxide ethylene glycol solution, continuously stir during the addition process, and then stir for 30 min to obtain a precursor of aluminum-doped nano-zinc oxide sol.

[0026] Centrifuge the precursor, wash it 3 times with ethanol and water, dry it in vacuum at 80 °C, and calcine it at 550 °C for 2 h in a nitrogen atmosphere to obtain the conductive aluminum-doped nano-AZO powder.

[0027] As a preferred embodiment of the preparation method of the present invention, wherein: the molar ratio of Al / Zn of the zinc chloride and aluminum chloride hexahydrate is 3%; the final pH value of the reaction system of the precursor of the aluminum-doped nano-zinc oxide sol is 9-10.

[0028] As a preferred embodiment of the preparation method of the present invention, wherein: for the wet modification of the nano-AZO powder, the modification method is as follows:

[0029] Disperse the conductive AZO powder in water and ball mill it for 30 min to obtain an AZO dispersion.

[0030] Mix 3-glycidoxypropyltrimethoxysilane kh560 with an ethanol aqueous solution evenly, pre-hydrolyze it for 10-30 min, slowly drop it into the AZO dispersion, continuously stir during the dropping process, and ball mill it for 30 min. Then stir and react at room temperature for 2 h, then raise the temperature to 60 °C and react for 2 h, cool to room temperature to obtain a kh560-modified AZO dispersion.

[0031] Pre-hydrolyze kh131 and kh902.

[0032] At room temperature, slowly drop the pre-hydrolyzed methyltrimethoxysilane kh131 into the kh560-modified AZO dispersion, stir for 1 h, then slowly add the pre-hydrolyzed γ-aminopropylmethyldiethoxysilane kh902, stir at room temperature for 2 h, then raise the temperature to 60 °C and stir and react for 2 h, cool to room temperature, filter and wash, and dry in vacuum at 80 °C to obtain the modified nano-AZO powder.

[0033] As a preferred embodiment of the preparation method of the present invention, it is as follows: The silicone-modified polyaspartic acid ester resin, solvent, and dispersant are stirred evenly, wherein the mass ratio of the silicone-modified polyaspartic acid ester resin to the solvent is 10:3, and the dosage of the dispersant is 15% of the mass of the conductive carbon black.

[0034] As a preferred embodiment of the preparation method of the present invention, it is as follows: Conductive carbon black, modified nano-AZO powder, and nano-polyaniline are added, wherein the dosages of the conductive carbon black, modified nano-AZO powder, and nano-polyaniline are 20 - 40 parts, 0.5 - 3.5 parts, and 3 - 10 parts respectively.

[0035] As a preferred embodiment of the preparation method of the present invention, it is as follows: A leveling agent, anti-settling agent, defoaming agent, and solvent are added, wherein the leveling agent is 0.1 - 0.5 part, the anti-settling agent is 0.1 - 1 part, the defoaming agent is 0.1 - 1 part, and the solvent is 10 - 20 parts.

[0036] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a modified polyurea-based conductive anti-corrosion coating.

[0037] Advantages of the present invention:

[0038] The modified polyurea-based conductive anti-corrosion coating prepared by the present invention uses conductive carbon black as the main conductive filler, and polyaniline and AZO as auxiliary conductive fillers. By utilizing the amino groups carried by polyaniline and the amino functional groups introduced by modified AZO, they can be chemically grafted onto the polyurea main chain during the curing process, enabling the coating to have better conductivity and adhesion, thereby improving the corrosion resistance of the coating.

[0039] The modified polyurea-based conductive anti-corrosion coating of the present invention is based on a modified polyurea coating. When the carbon black content is 30%, polyaniline is 8%, and modified AZO is 1.5%, the coating has the best adhesion and aging resistance, and at the same time, the resistivity is only 60.3 Ω·cm, which is a conductive anti-corrosion coating with great application prospects. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0041] Figure 1 It is a graph showing the relationship between the conductive carbon black content and the coating resistivity and adhesion measured in Example 5.

[0042] Figure 2Graph showing the relationship between the content of conductive polyaniline and the resistivity and adhesion of the coating measured in Example 6.

[0043] Figure 3 TEM images of AZO measured in Example 7 at different heating times (a: 0 h; b: 2 h; c: 4 h; d: 6 h).

[0044] Figure 4 Graph showing the relationship between the content of conductive AZO and the resistivity and adhesion of the coating measured in Example 7. Detailed implementation manners

[0045] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given in combination with the embodiments of the specification.

[0046] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0047] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive with other embodiments.

[0048] The reagents used in the embodiments of the present invention are shown in Table 1, and the instruments used are shown in Table 2.

[0049] Table 1

[0050]

[0051]

[0052] Table 2

[0053] Serial number Experimental instrument (model) Place of origin 1 Electronic balance (FA-2004B) Shanghai Youke Instrument Co., Ltd. 2 Electrically heated forced air drying oven (101-3AB) Tianjin Test Instrument Co., Ltd. 3 Digital display constant temperature magnetic stirrer (85-2A) Jintan Chengdong Xinrui Instrument Factory 4 NDJ-1 Rotary viscometer Shanghai Lichen Instrument Technology Co., Ltd. 5 Full-range planetary ball mill (PMQW2) Nanjing Chishun Technology Development Co., Ltd. 6 Adhesion tester (BGD500 / S) Biaogeda Precision Instruments (Guangzhou) Co., Ltd. 7 Four-probe conductivity measuring instrument (HRMS-800) Bailibo Technology (China) Co., Ltd.

[0054] Example 1

[0055] Preparation of nano-polyaniline, including the following steps:

[0056] Dissolve 1.42 g of aniline (An) in 48 mL of ethylene glycol containing hydrochloric acid (hydrochloric acid is 0.5 mol / L) (EG), and stir evenly with a magnetic stirrer to obtain an An solution;

[0057] According to the molar ratio of oxidant APS to An being 1, an appropriate amount of ammonium persulfate (APS) was dissolved in 38 mL of EG, and stirred to dissolve to obtain an APS solution;

[0058] Under stirring conditions, the APS solution was slowly added dropwise to the An solution, and stirred and reacted for 24 hours. The reaction product was centrifuged and separated by a high-speed centrifuge (5000 r / min), and the product was washed twice with ethanol and distilled water respectively, and vacuum dried at 45 °C for 24 hours to obtain conductive nano-polyaniline.

[0059] Example 2

[0060] Preparation of conductive aluminum-doped nano-zinc oxide (AZO), including the following steps:

[0061] A certain amount of zinc chloride and aluminum chloride hexahydrate (molar ratio of Al / Zn being 3%) were dissolved in ethylene glycol to prepare a mixed ethylene glycol solution of zinc chloride with a concentration of 1 mol / L. 2+ The aluminum chloride hexahydrate mixed ethylene glycol solution with a concentration of 1 mol / L.

[0062] Sodium hydroxide was dissolved in ethylene glycol to obtain a 2 mol / L sodium hydroxide ethylene glycol solution;

[0063] Under stirring conditions, the measured zinc chloride and aluminum chloride mixed solution was quickly added to a quantitative sodium hydroxide solution, so that the final pH value of the reaction system was 9-10, and stirring was continued for 30 min to obtain a precursor of aluminum-doped nano-zinc oxide sol;

[0064] The precursor was centrifuged and separated, washed 3 times with ethanol and water, vacuum dried at 80 °C, and then calcined at 550 °C for 2 hours in a nitrogen atmosphere to obtain conductive nano-AZO powder.

[0065] Example 3

[0066] Wet modification of nano-AZO powder, including the following steps:

[0067] (1) Dispersion of nano-AZO powder and modification with kh560:

[0068] 10 g of conductive nano-AZO powder was dispersed in 90 g of water (solid content 10%), and ball milled for 30 minutes to obtain an AZO dispersion;

[0069] 1 g of 3-glycidoxypropyltrimethoxysilane (kh560) was weighed, added to 10 g of an ethanol aqueous solution (containing about 20% water), pre-hydrolyzed for 10-30 minutes first, and then slowly added dropwise to the continuously stirred AZO dispersion. After ball milling and dispersing and modifying for another 30 minutes, it was transferred to a beaker and continuously stirred and reacted at room temperature for 2 hours; the temperature was raised to 60 °C and reacted for another 2 hours, and then cooled to room temperature.

[0070] (2) Modification of KH131 and KH902:

[0071] The dispersion modified with KH560 was slowly added dropwise with pre-hydrolyzed KH131 (0.5 g) at room temperature. After stirring at room temperature for 1 hour, pre-hydrolyzed KH902 (0.5 g) was slowly added dropwise. After stirring at room temperature for 2 hours, the temperature was raised to 60 °C and stirring reaction continued for 2 hours. Then it was cooled to room temperature, filtered and washed, and dried at 80 °C under vacuum to obtain modified nano-AZO powder.

[0072] Example 4

[0073] Preparation of polyurea-modified conductive polyaniline anticorrosive coating, including the following steps:

[0074] Preparation of siloxane-modified polyaspartate resin: Under nitrogen protection, first stir and react polyaspartate resin with diisocyanate for pre-polymerization, then add silane coupling agent and stir and react for 0.5 - 4 h to obtain siloxane-modified polyaspartate resin.

[0075] Weigh 50 g of siloxane-modified polyaspartate resin, 15 g of solvent (ethyl acetate or PMA), and 15% of dispersant 7631 (Guangzhou Slok Chemical Co., Ltd.) of conductive carbon black, stir evenly, add 30% of conductive carbon black, 1.5% of modified nano-AZO powder and 8% of conductive nano-polyaniline in total amount of component A. After dispersing evenly, ball mill for 30 minutes (15 minutes for each direction), then add 0.4% of leveling agent, 0.2% of anti-settling agent, 0.3% of defoaming agent in total amount of component A, and then adjust the viscosity with solvent. After mixing and stirring evenly, component A is obtained;

[0076] Component B is a curing agent of HDI trimer and 10% solvent (PMA or ethyl acetate).

[0077] According to the NCO index of 1.05, measure component A and component B, quickly mix them at room temperature and stir evenly to obtain polyurea-modified conductive polyaniline anticorrosive coating.

[0078] Example 5

[0079] The difference between this example and Example 4 is that the addition amounts of conductive carbon black are 5 w / %, 10 w / %, 20 w / %, 40 w / %, 50 w / %, 60 w / % respectively, and the other parameters and steps are the same as those in Example 4, and polyurea-modified conductive polyaniline anticorrosive coatings with different addition amounts of conductive carbon black are prepared.

[0080] The conductivity of the polyurea-modified conductive polyaniline anticorrosive coatings prepared in Example 4 and this example was tested. A coating (with a thickness of about 0.1 - 0.5 mm) was made on a glass slide and directly tested for conductivity using a four-probe conductivity tester. The same sample was tested 3 times, and the average value was taken as its resistivity.

[0081] The polyurea-modified conductive polyaniline anticorrosive coatings prepared in Example 4 and this example were scraped into films on glass slides, and the coating properties were tested after aging at room temperature for 7 days. Among them, the leveling property of the coating was measured according to Standard GB / T 1750 - 1979, the glossiness was measured according to GB_9754 - 2007, the flexibility of the coating was measured according to GB / T 1731 - 2020, the adhesion of the coating was measured according to GB / T 5210 - 2006, and the salt spray resistance was measured according to GB / T 1771 - 2007.

[0082] The results of the conductivity test and the coating property test are shown in Table 3.

[0083] Table 3 Influence of Conductive Carbon Black on Coating Properties

[0084]

[0085] It can be seen from Table 3 that as the content of the conductive powder increases, the volume conductivity of the coating gradually decreases. When the content of the conductive carbon black powder is < 20%, the resistivity drops sharply. After the content of the conductive carbon black is greater than 30%, it tends to level off; when the addition amount is 60%, the volume resistivity of the coating reaches the minimum value.

[0086] Research shows that the influence of the content of carbon-based fillers on the conductive performance of the coating is consistent with the "percolation effect". When the filling amount of the conductive particles reaches a certain specific value (the packing density of the insulating polymer is small to a certain specific value), an electric current channel can be formed, and only then does the coating have conductivity. This specific value is called the percolation critical value. The relationship between the content of the conductive carbon black and the resistivity and adhesion of the coating is as Figure 1 shown, and it can be known from Figure 1 that the percolation critical value of the coating of the coating prepared in the present invention is about 15%.

[0087] On the other hand, as the content of the conductive carbon black increases, the adhesion first increases and then decreases significantly. This is mainly because after the filler is excessive, the leveling property becomes poor, and both the coating strength and flexibility decrease, resulting in a poor film-forming density, an increase in surface roughness, and even obvious pinholes, leading to a decrease in both the glossiness and adhesion, and thus a poor salt spray resistance. Therefore, considering the performance and cost, the addition amount of the conductive carbon black in the formula of this conductive coating is 20% - 40%, and 30% is the best.

[0088] Example 6

[0089] The difference between this example and Example 4 lies in that the addition amounts of conductive nano-polyaniline are 0 w / %, 3 w / %, 5 w / %, 10 w / %, 15 w / %, and 20 w / % respectively, and the remaining parameters and steps are the same as those in Example 4, and polyurea-modified conductive polyaniline anticorrosive coatings with different addition amounts of conductive nano-polyaniline are prepared.

[0090] Performance tests were carried out on the polyurea-modified conductive polyaniline anticorrosive coatings prepared in Example 4 and this example. The test method was the same as that in Example 5, and the test results are shown in Table 4. The relationship between the content of conductive polyaniline and the resistivity and adhesion of the coating is as Figure 2 shown.

[0091] Table 4 Influence of conductive nano-polyaniline on coating performance

[0092]

[0093] As can be seen from Table 4 and Figure 2 it can be seen that with the increase of the addition amount of conductive polyaniline, the conductivity gradually increases, while the adhesion first increases slightly and then gradually decreases. This is mainly because when the nano-material is added in an appropriate amount, it has a certain strengthening effect. In addition, the amino group of polyaniline can react with part of the curing agent, causing chemical grafting between the polyaniline chain and the polyurea chain, thereby improving its adhesion and reducing the resistivity of the polymer chain.

[0094] When the addition amount is too high (>8%), since more polyaniline is not grafted with polyurea, similar to the blending principle, the leveling property of the coating becomes poor, while the conductive performance basically remains stable. As can be seen from Table 4, after adding polyaniline, the anticorrosive performance of the coating has been improved to some extent, which is mainly due to the good anticorrosive ability of polyaniline itself. Therefore, the addition amount of conductive nano-polyaniline in the conductive coating formula of the present invention is 3% - 8%, and 8% is the best.

[0095] Example 7

[0096] The difference between this example and Example 4 lies in that the addition amounts of modified nano-AZO powder are 0 w / %, 0.5 w / %, 1 w / %, 2 w / %, 2.5 w / %, 3 w / %, and 3.5 w / % respectively, and the remaining parameters and steps are the same as those in Example 4, and polyurea-modified conductive polyaniline anticorrosive coatings with different addition amounts of modified nano-AZO powder are prepared.

[0097] The TEM images of the modified nano-AZO powder of the present invention at different heating times are as Figure 3 shown, and it can be seen that the AZO particle size is about 10 nm.

[0098] Performance tests were carried out on the polyurea-modified conductive polyaniline anticorrosive coatings prepared in Example 4 and this example. The test method was the same as that in Example 5, and the test results are shown in Table 5. The relationship between the content of conductive polyaniline and the resistivity and adhesion of the coating is asFigure 4 as shown

[0099] Table 5 Influence of Modified Nano-AZO Powder on Coating Properties

[0100]

[0101] From Table 5 and Figure 4 it can be seen that after adding nano-AZO, the gloss and adhesion of the coating increase significantly, and the resistivity gradually decreases. When the addition amount of nano-AZO is 1.5%, the adhesion reaches the maximum value and then decreases slowly; when the addition amount is greater than 2%, the decreasing trend of the resistivity becomes gentle.

[0102] The main reason is that due to the very small particle size of the added nano-AZO, it will further fill the gaps between carbon black and polyaniline, making the surface smoother and brighter, increasing the gloss, and at the same time making the conductive network channels more perfect, resulting in a decrease in resistivity. Similarly, it will also increase the contact area between the coating and the substrate, and the penetration degree of the nanoparticles is stronger. The amino groups carried on the surface can react with the curing agent to form polyurea and graft onto the resin, significantly increasing the adhesion.

[0103] When the addition amount is too large, the crosslinking degree is too high. Due to excessive reaction, the internal stress in the coating will increase, resulting in a decrease in adhesion. On the other hand, the flexibility of the coating becomes better in the presence of nano-AZO, so the coating is more difficult to crack, and the salt spray resistance performance is excellent, at least greater than 30 days. Therefore, considering the performance and cost, the addition amount of the modified nano-AZO powder in the conductive coating formula of the present invention is 1% - 2%, and 1.5% is the best.

[0104] The modified polyurea-based conductive anti-corrosion coating prepared by the present invention uses conductive carbon black as the main conductive filler, and polyaniline and AZO as auxiliary conductive fillers. First, the surface of nano-AZO is chemically modified to introduce functional groups, and by using the amino groups carried by polyaniline and the amino functional groups introduced by modified AZO, during the curing process, through the functional groups on the surface of nano-AZO and the amine groups on the surface of polyaniline, it reacts with the curing agent and grafts onto the film-forming resin chain, which can improve the dispersion of the filler in the coating. At the same time, combined with the physical mixing of carbon black and the film-forming resin, a conductive anti-corrosion coating with excellent adhesion and conductive performance can be obtained.

[0105] The modified polyurea-based conductive anti-corrosion coating of the present invention is based on a modified polyurea coating. When the carbon black content is 30%, polyaniline is 8%, and modified AZO is 1.5%, the coating has the best adhesion and anti-aging performance, and at the same time the resistivity is only 60.3 Ω·cm, which is a conductive anti-corrosion coating with great application prospects.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the present invention.

Claims

1. A preparation method of a modified polyurea-based conductive anticorrosive coating, characterized in that: Including, Preparing nano-polyaniline; Preparation of Conductive Aluminum-Doped Nano-AZO Powder: Zinc chloride and aluminum chloride hexahydrate are dissolved in ethylene glycol to prepare a mixed ethylene glycol solution of zinc chloride and aluminum chloride with a concentration of 1 mol / L of Zn 2+ ; Dissolving sodium hydroxide in ethylene glycol to prepare a 2 mol / L sodium hydroxide ethylene glycol solution; Quickly adding a mixed ethylene glycol solution of zinc chloride and aluminum chloride to a quantitative sodium hydroxide ethylene glycol solution, continuously stirring during the addition process, and then stirring for 30 min to obtain a precursor of aluminum-doped nano-zinc oxide sol; Centrifuging the precursor, washing it 3 times with ethanol and water, drying it in vacuum at 80 °C, and calcining it at 550 °C for 2 h in a nitrogen atmosphere to obtain conductive aluminum-doped nano-AZO powder; Wet modification of nano-AZO powder: Dispersing conductive AZO powder in water and ball milling for 30 min to obtain an AZO dispersion; Mixing 3-glycidylpropyltrimethoxysilane kh560 with an ethanol aqueous solution evenly, pre-hydrolyzing for 10 - 30 min, slowly dropping it into the AZO dispersion, continuously stirring during the dropping process, and ball milling for 30 min, then stirring and reacting at room temperature for 2 h, then heating to 60 °C and reacting for 2 h, cooling to room temperature to obtain a kh560-modified AZO dispersion; Pre-hydrolyzing kh131 and kh902; At room temperature, slowly dropping the pre-hydrolyzed methyltrimethoxysilane kh131 into the kh560-modified AZO dispersion, stirring for 1 h, then slowly dropping the pre-hydrolyzed γ-aminopropylmethyldiethoxysilane kh902, stirring at room temperature for 2 h, then heating to 60 °C and stirring and reacting for 2 h, cooling to room temperature, filtering and washing, and drying in vacuum at 80 °C to obtain the modified nano-AZO powder; Stirring the siloxane-modified polyaspartate resin, solvent, and dispersant evenly, adding conductive carbon black, the modified nano-AZO powder, and nano-polyaniline, dispersing evenly, ball milling, adding a leveling agent, anti-settling agent, defoaming agent, and solvent, and stirring evenly to obtain Component A; among them, the mass ratio of the siloxane-modified polyaspartate resin to the solvent is 10:3, and the dosage of the dispersant is 15% of the mass of the conductive carbon black; Mixing the HDI trimer with the solvent evenly to obtain the curing agent Component B; Measuring Component A and Component B according to an NCO index of 1.05, quickly mixing them at room temperature, and stirring evenly to obtain the modified polyurea-based conductive anticorrosive coating; The addition of conductive carbon black, the modified nano-AZO powder, and nano-polyaniline, among which the dosages of conductive carbon black, the modified nano-AZO powder, and nano-polyaniline are 20 - 40 parts, 0.5 - 3.5 parts, and 3 - 10 parts respectively.

2. The preparation method according to claim 1, characterized in that: The preparation of nano-polyaniline, among which the preparation method of nano-polyaniline is: Dissolving aniline An in ethylene glycol EG containing hydrochloric acid and stirring evenly to obtain an An solution; Dissolving ammonium persulfate APS in ethylene glycol EG, dissolving and stirring to obtain an APS solution; Slowly dropping the APS solution into the An solution, continuously stirring during the dropping process, then stirring for 24 h, centrifuging, washing the product twice with ethanol and distilled water respectively, and drying in vacuum at 45 °C for 24 h to obtain conductive nano-polyaniline.

3. The preparation method according to claim 2, characterized in that: The molar ratio of ammonium persulfate APS to aniline An is 1:1 - 1.1:

1.

4. The preparation method according to claim 1, characterized in that: The molar ratio of Al / Zn of the zinc chloride and aluminum chloride hexahydrate is 3%; the final pH value of the reaction system of the precursor of the aluminum-doped nano-zinc oxide sol is 9 to 10.

5. The preparation method according to claim 1, characterized in that: Leveling agent, anti-settling agent, defoaming agent, and solvent are added, wherein the leveling agent is 0.1 to 0.5 parts, the anti-settling agent is 0.1 to 1 part, the defoaming agent is 0.1 to 1 part, and the solvent is 10 to 20 parts.

6. Application of the modified polyurea-based conductive anticorrosive coating prepared by the preparation method according to any one of claims 1 to 5.

Images