A nanocomposite material EP@DA@GO@M and a preparation method thereof, and a water-based epoxy heavy-duty anticorrosive coating with a slow-release function and a preparation method thereof

Abstract

The present application relates to the paint technical field, especially relates to a kind of nano composite material EP@DA@GO@M and preparation method thereof, water-based epoxy heavy-duty anticorrosive coating with slow-release function and preparation method thereof.The preparation method of the nano composite material EP@DA@GO@M includes the following steps: water-based graphene slurry a is diluted to obtain graphene slurry b;Dopamine, catalyst, water and 1,6-hexanediol diglycidyl ether are mixed to form mixed solution C;Graphene slurry b is added in mixed solution C, and mixed at (25~35) ℃ for (20~24) h to obtain composite material EP@DA@GO;2-mercapto benzimidazole anhydrous ethanol solution is added to silane coupling agent to obtain mixture KM;After EP@DA@GO, water and KM are mixed, heated to react to obtain nano composite material EP@DA@GO@M.The nano composite material EP@DA@GO@M prepared by the present application is applied in water-based epoxy coating, can effectively improve the anticorrosion of water-based epoxy coating, realizes long-acting anticorrosive function of water-based epoxy coating, in addition, its preparation raw material is biological material, and coating is green and environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a nanocomposite material EP@DA@GO@M and its preparation method, and a waterborne epoxy heavy-duty anti-corrosion coating with slow-release function and its preparation method. Background Technology

[0002] Waterborne coatings, as one of the three major environmentally friendly coatings, have developed rapidly. However, due to their unique film-forming method, the large amount of solvents and additives required, and the strong hydrophilicity of the film-forming material, their corrosion resistance has not been effectively improved. Commonly available waterborne anti-corrosion coatings typically have a neutral salt spray time of 600-700 hours, which is insufficient for long-term protection. Therefore, improving the corrosion resistance of waterborne epoxy coatings has always been a research hotspot in the field of corrosion protection.

[0003] Zhu Ke et al. studied the synthesis of a TETA-modified GO dispersion (TGO) by ball milling triethylenetetramine (TETA) and graphene oxide (GO). Then, bisphenol A type epoxy resin E44, trimethylolpropane triglycidyl ether (TPEG), methoxy polyethylene oxide-2,3-epoxypropane (MEH), and γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) were sequentially added to the TGO dispersion, and an in-situ polymerization method was used to synthesize a graphene oxide-waterborne epoxy resin curing agent (TGO-WPEA). The results showed that the waterborne epoxy resin curing agent (WPEA) molecules were covalently bonded to the GO surface, improving the dispersion stability and grafting rate of GO in epoxy resin (EP), and enhancing the shielding performance of the TGO-EP composite coating against corrosive media.

[0004] Chinese invention patent application CN 202310305489.2 discloses a two-component waterborne epoxy anticorrosive coating and its preparation method. The coating consists of waterborne epoxy resin, silica sol, zinc phosphate, and a formulation design that provides good anticorrosive properties.

[0005] Chinese invention patent application CN115216170A discloses a waterborne epoxy resin anticorrosive coating and its preparation method. This invention prepares amino-functionalized siloxanes through the hydrolysis and condensation of a silane coupling agent. Simultaneously, it utilizes tannic acid as a reaction center to graft NH2-POSS onto the SiO2 surface to prepare a POSS-TA-SiO2 hybrid material. The POSS-TA-SiO2 hybrid material is then used as a filler to further prepare the waterborne epoxy anticorrosive coating. The results show that the POSS-TA-SiO2 hybrid material effectively improves the coating's crosslinking density, hydrophobicity, and corrosion resistance.

[0006] Chinese invention patent application CN 116751503A discloses a water-based high-adhesion epoxy anti-corrosion coating and its preparation method. Component A of this invention includes water-based epoxy resin, micro / nano-composite silica, sodium alginate, graphene oxide, diatomaceous earth, zinc phosphate, and aniline / 5-aminosalicylic acid copolymer, while component B includes polyamide, urea, calcium lactate, and deionized water. This invention effectively promotes the dispersion of graphene in the system and possesses a certain degree of self-healing ability, giving the coating excellent anti-corrosion properties. Summary of the Invention

[0007] To address the shortcomings of existing waterborne epoxy heavy-duty anti-corrosion coatings mentioned in the background section, this invention provides a nanocomposite material EP@DA@GO@M and its preparation method, as well as a waterborne epoxy heavy-duty anti-corrosion coating with slow-release function and its preparation method. The purpose of this invention is to provide a nanocomposite material EP@DA@GO@M that can be used to prepare environmentally friendly and long-lasting anti-corrosion waterborne epoxy heavy-duty anti-corrosion coatings. This invention modifies dopamine with 1,6-hexanediol diglycidyl ether to form EP@DA. EP@DA is further reacted with graphene (GO) to introduce catechol groups and epoxy groups onto the GO surface, forming EP@DA@GO. The nanocomposite material EP@DA@GO@M is further prepared by utilizing the hydrogen bonding and electronic coupling between the -OH groups in the catechol groups, the -OH and -NH- groups in the modified dopamine, and the NH and C=N groups in 2-mercaptobenzimidazole (M). This material is an active composite material. When applied to waterborne epoxy coatings, it can simultaneously increase the crosslinking density of the waterborne epoxy coating and provide a triple effect of physical shielding and chemical slow-release synergistic anti-corrosion, effectively improving the anti-corrosion properties of waterborne epoxy coatings. The technical solution is as follows:

[0008] The preparation method of the nanocomposite material EP@DA@GO@M includes the following steps:

[0009] Aqueous graphene (GO) slurry a was diluted with water to a mass content of (0.3-0.7)% to obtain graphene slurry b;

[0010] Under reflux, dopamine, catalyst, water and 1,6-hexanediol diglycidyl ether were mixed and heated to (40-50) °C and stirred to dissolve dopamine. The mixture was then dispersed for (2-2.5) h to form a mixed solution C.

[0011] Graphene slurry b was added to mixed solution C and mixed at (25-35)℃ for (20-24) h. The product was then filtered, washed, and dried to obtain the composite material EP@DA@GO.

[0012] A silane coupling agent was added to an anhydrous ethanol solution of 2-mercaptobenzimidazole (M) to obtain a mixture KM;

[0013] After mixing EP@DA@GO, water and KM, the system was heated to 35℃~45℃ and refluxed for 1.5~2.0h. The product was then filtered, washed and dried to obtain the nanocomposite material EP@DA@GO@M.

[0014] In some embodiments, the mass ratio of dopamine, catalyst, 1,6-hexanediol diglycidyl ether, and graphene slurry b is (1.0-1.5):(0.002-0.006):(1.5-1.75):(180-220); the catalyst is catalyst K54.

[0015] In some embodiments, during the preparation of the KM mixture, the mass content of the 2-mercaptobenzimidazole anhydrous ethanol solution is (8-15)%; the amount of the silane coupling agent is (1-1.5)% of the mass of the 2-mercaptobenzimidazole anhydrous ethanol solution; and the silane coupling agent is KH-560.

[0016] In some embodiments, during the preparation of EP@DA@GO@M, the mass ratio of EP@DA@GO to KM is 10:(30-50).

[0017] In some embodiments, during the preparation of EP@DA@GO, the reaction product is filtered, and the residue is washed with anhydrous ethanol 3-5 times, and then dried at (70-90)℃ for (5-6) hours to obtain EP@DA@GO; during the preparation of EP@DA@GO@M, the reaction product is filtered, and the residue is washed with water 3-5 times, and then dried at (55-65)℃ for (6-8) hours to obtain EP@DA@GO@M.

[0018] The present invention also provides a nanocomposite material EP@DA@GO@M, which is prepared by the nanocomposite material preparation method described above.

[0019] The present invention also provides a water-based epoxy heavy-duty anti-corrosion coating with a slow-release function, comprising component A and component B, wherein component A comprises the nanocomposite material EP@DA@GO@M as described in claim 6.

[0020] In some embodiments, by weight, component A comprises: 10-25 parts water, 0.1-1 parts dispersant, 0.1-1 parts substrate wetting agent, 5-10 parts cosolvent, 0.1-1 parts defoamer, 5-10 parts nanocomposite material EP@DA@GO@M, 5-15 parts flake filler, 5-15 parts extender filler, 10-30 parts rust-inhibiting filler, 0.1-2.0 parts thickener, 5-15 parts waterborne epoxy resin emulsion A, and 10-30 parts waterborne epoxy resin emulsion B; by weight, component B comprises: 5-10 parts water, 0.1-1.5 parts pH adjuster, 0.1-1.5 parts flash rust inhibitor, and 80-99 parts waterborne epoxy curing agent; the weight ratio of component A to component B is (5-8):1.

[0021] In some embodiments, the dispersant is one or more combinations of BYK-190, BYK-151, and COATEXP90.

[0022] In some embodiments, the substrate wetting agent is one or more combinations of BYK-348, Hydropalat 140, and Tego wet 270.

[0023] In some embodiments, the co-solvent is a mixture of propylene glycol methyl ether and diethylene glycol butyl ether in a mass ratio of 5:3.

[0024] In some embodiments, the defoamer is one or more combinations of NXZ, Foamex 830, Surfynol 104E, and Tego 450.

[0025] In some embodiments, the sheet-like filler is sericite powder.

[0026] In some embodiments, the filler material is one or more combinations of barite powder, titanium dioxide, and precipitated barium sulfate.

[0027] In some embodiments, the anti-rust pigment is one or more of zinc phosphate, composite nano-iron-titanium powder, and aluminum tripolyphosphate; preferably, the mass ratio of zinc phosphate to composite nano-iron-titanium powder is 1:1.

[0028] In some embodiments, the thickener is one or more combinations of BR-125P, WT-105A, and WT-204.

[0029] In some embodiments, the aqueous epoxy resin emulsion A is E51 type epoxy emulsion 5175.

[0030] In some embodiments, the aqueous epoxy resin emulsion B is E20 type epoxy emulsion 2060H.

[0031] In some embodiments, the pH adjuster is one or a combination of two of DMEA and AMP-95; preferably, the mass ratio of DMEA to AMP-95 is 2:1.

[0032] In some embodiments, the flash rust inhibitor is FA-179.

[0033] In some embodiments, the waterborne epoxy curing agent is a mixture of KEH-305 and BC901 in a mass ratio of 1:3.

[0034] This invention also provides a method for preparing the waterborne epoxy heavy-duty anti-corrosion coating with slow-release function as described above, wherein the preparation process of component A is as follows:

[0035] Disperse the water, dispersant, substrate wetting agent, cosolvent and defoamer evenly;

[0036] Then, the nanocomposite material EP@DA@GO@M is added and dispersed evenly.

[0037] Then add the sheet filler, bulk filler, and rust-inhibiting filler and disperse them evenly;

[0038] Then add a thickener and disperse at high speed until the fineness is ≤80μm;

[0039] Finally, add waterborne epoxy resin emulsion A, waterborne epoxy resin emulsion B, and defoamer, disperse evenly, and filter to obtain component A;

[0040] The preparation process of component B is as follows:

[0041] The components B are obtained by dispersing water, regulator, pH adjuster, anti-flash rust agent and water-based epoxy curing agent evenly and filtering.

[0042] Based on the above, compared with the prior art, the nanocomposite material EP@DA@GO@M prepared by the present invention has the following beneficial effects:

[0043] The nanocomposite material EP@DA@GO@M provided by this invention can be used to prepare environmentally friendly and long-lasting anti-corrosion waterborne epoxy heavy-duty anti-corrosion coatings. The prepared nanocomposite material EP@DA@GO@M is an active composite material. When applied to waterborne epoxy coatings, it can simultaneously improve the crosslinking density of the waterborne epoxy coating and provide a triple effect of physical shielding and chemical slow-release synergistic anti-corrosion, effectively improving the anti-corrosion performance of the waterborne epoxy coating. Furthermore, the electronic coordination between the catechol groups, epoxy groups, and -OH groups in EP@DA@GO@M and the epoxy resin, as well as the interaction between the epoxy groups in EP@DA@GO@M and the amino groups in the curing agent, synergistically improve the dispersibility of EP@DA@GO@M in the epoxy coating, further improving its application efficiency and achieving the long-lasting anti-corrosion function of the waterborne epoxy coating. In addition, the raw materials for preparing EP@DA@GO@M, dopamine and 2-mercaptobenzimidazole, are both bio-based materials, making the coating green and environmentally friendly.

[0044] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained by means of the structures and / or components pointed out in the description and claims. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0047] This invention provides a method for preparing a waterborne epoxy heavy-duty anti-corrosion coating with a slow-release function, comprising the following steps:

[0048] The preparation method of component A is as follows:

[0049] (1) Add deionized water, cosolvent, dispersant, substrate wetting agent and defoamer, start the high-speed disperser, adjust the speed to 300-800 r / min, and disperse for 10-15 min;

[0050] (2) Add the nanocomposite material EP@DA@GO@M and disperse it at high speed for 1.0 h at a rotation speed of 800-1500 r / min;

[0051] (3) Add the sheet-like filler, bulk filler and rust-preventive filler, and adjust the rotation speed to 800-1500 r / min to disperse them evenly;

[0052] (4) Add thickener and disperse at high speed of 800-1500 r / min until the fineness is ≤80 μm;

[0053] (5) Add waterborne epoxy resin emulsion A, waterborne epoxy resin emulsion B, and defoamer, and disperse at high speed of 800-1500 r / min for 15 min;

[0054] (6) Filter and package to obtain component A as the finished product.

[0055] The preparation method of component B is as follows:

[0056] Add deionized water, regulator, pH adjuster, anti-flash rust agent and water-based epoxy curing agent, start stirring, adjust the speed to 300-800 r / min, disperse evenly, filter and package to obtain component B finished product.

[0057] The formulations of components A and B are as follows:

[0058] By weight, component A comprises: 10-25 parts water, 0.1-1 parts dispersant, 0.1-1 parts substrate wetting agent, 5-10 parts cosolvent, 0.1-1 parts defoamer, 5-10 parts nanocomposite material EP@DA@GO@M, 5-15 parts flake filler, 5-15 parts extender filler, 10-30 parts rust-inhibiting filler, 0.1-2.0 parts thickener, 5-15 parts waterborne epoxy resin emulsion A, and 10-30 parts waterborne epoxy resin emulsion B;

[0059] By weight, component B comprises: 5-10 parts water, 0.1-1.5 parts pH adjuster, 0.1-1.5 parts flash rust inhibitor, and 80-99 parts water-based epoxy curing agent;

[0060] The weight ratio of component A to component B is (5-8):1.

[0061] The selected raw material nanocomposite material is specially formulated, and its specific preparation process is as follows:

[0062] a. Add deionized water to dilute commercially available water-based graphene (GO) slurry a (brand name GRF-FLGAD) with a mass content of 10% to a pure graphene mass content of (0.3-0.7)%, and disperse at high speed of 2000-2500 rpm for (2-2.5) h to obtain graphene slurry b.

[0063] b. In a four-necked flask, turn on the magnetic stirrer and cooling water, adjust the speed to 1500 rpm, slowly add dopamine, deionized water and 1,6-hexanediol diglycidyl ether, add catalyst K54, heat to (40-50)℃, disperse at high speed of 1500 rpm until dopamine is completely dissolved, and then continue to disperse for 2 hours.

[0064] Weigh 200g of graphene slurry b and add it to a four-necked flask. Adjust the temperature to (25-35)℃ and disperse at high speed for (20-24)h. Filter by suction, wash with anhydrous ethanol and filter by suction 3-5 times, and then bake in an oven at (70-90)℃ for (5-6)h to obtain EP@DA@GO.

[0065] The mass ratio of dopamine, catalyst, 1,6-hexanediol diglycidyl ether, and graphene slurry b is (1.0-1.5):(0.002-0.006):(1.5-1.75):(180-220).

[0066] c. Dissolve 2-mercaptobenzimidazole (M) in anhydrous ethanol to form a solution M(aq) with a mass content of (8-15)%. Then add (1-1.5)% of silane coupling agent KH-560 to the aqueous solution, denoted as KM(aq), for later use.

[0067] d. Weigh EP@DA@GO, add deionized water, and disperse at 1500 rpm for 1.5 h; weigh KM(aq) and add it to the system, adjust the temperature of the four-necked flask to 35℃~45℃, turn on the cooling water, and continue dispersion for 1.5~2.0 h. The mass ratio of EP@DA@GO to KM is 10:(30~50).

[0068] e. Filter, wash with deionized water 3-5 times, and place in a (55-65) oven for (6-8) hours to obtain the nanocomposite material EP@DA@GO@M.

[0069] The present invention also provides the following embodiments and comparative formulations (unit: parts by weight), as shown in Tables 1-2 below:

[0070] Table 1

[0071]

[0072] Table 2

[0073]

[0074] Specifically, the raw materials selected for the embodiments and comparative examples are as follows:

[0075] 1. Example

[0076] Example 1

[0077] The dispersant is BYK-190;

[0078] The substrate wetting agent is BYK-348;

[0079] The co-solvent is a mixture of propylene glycol methyl ether and diethylene glycol butyl ether in a mass ratio of 5:3;

[0080] The defoamer is Foamex 830;

[0081] The sheet-like filler is sericite powder;

[0082] The filler material is precipitated barium sulfate;

[0083] The rust-preventive filler is a mixture of zinc phosphate and composite nano-iron-titanium powder in a 1:1 mass ratio; wherein, the composite nano-iron-titanium powder is WDB-500.

[0084] The thickener is BR-125P;

[0085] Waterborne epoxy resin emulsion A is E51 type epoxy emulsion 5175;

[0086] Waterborne epoxy resin emulsion B is E20 type epoxy emulsion 2060H;

[0087] The pH adjuster is a mixture of DMEA and AMP-95 in a 2:1 mass ratio.

[0088] The flash rust inhibitor is FA-179;

[0089] The water-based epoxy curing agent is a mixture of KEH-305 and BC901 in a mass ratio of 1:3.

[0090] Example 2

[0091] The dispersant is BYK-151;

[0092] The substrate wetting agent is Hydropalat 140;

[0093] The co-solvent is a mixture of propylene glycol methyl ether and diethylene glycol butyl ether in a mass ratio of 5:3;

[0094] The defoamer is NXZ;

[0095] The sheet-like filler is sericite powder;

[0096] The filler material is barite powder;

[0097] The rust-inhibiting filler is a composite nano-iron-titanium powder, wherein the composite nano-iron-titanium powder is WDB-500.

[0098] The thickener is WT-105A;

[0099] Waterborne epoxy resin emulsion A is E51 type epoxy emulsion 5175;

[0100] Waterborne epoxy resin emulsion B is E20 type epoxy emulsion 2060H;

[0101] The pH adjuster is a mixture of DMEA and AMP-95 in a 1:1 mass ratio;

[0102] The flash rust inhibitor is FA-179;

[0103] The water-based epoxy curing agent is a mixture of KEH-305 and BC901 in a mass ratio of 1:3.

[0104] Example 3

[0105] The dispersant is COATEX P90;

[0106] The substrate wetting agent is Tego wet 270.

[0107] The co-solvent is a mixture of propylene glycol methyl ether and diethylene glycol butyl ether in a mass ratio of 5:3;

[0108] The defoamer is Tego 450;

[0109] The sheet-like filler is sericite powder;

[0110] The filler material is a mixture of titanium dioxide and precipitated barium sulfate in a mass ratio of 1:2;

[0111] The rust-preventive filler is aluminum tripolyphosphate;

[0112] The thickener is WT-204;

[0113] Waterborne epoxy resin emulsion A is E51 type epoxy emulsion 5175;

[0114] Waterborne epoxy resin emulsion B is E20 type epoxy emulsion 2060H;

[0115] The pH adjuster is a mixture of DMEA and AMP-95 in a mass ratio of 1:2;

[0116] The flash rust inhibitor is FA-179;

[0117] The water-based epoxy curing agent is a mixture of KEH-305 and BC901 in a mass ratio of 1:3.

[0118] The preparation process for Examples 1-3 is as follows:

[0119] The preparation method of component A is as follows:

[0120] (1) Add deionized water, cosolvent, dispersant, substrate wetting agent and defoamer, start the high-speed disperser, adjust the speed to 500 r / min, and disperse for 13 min;

[0121] (2) Add the nanocomposite material EP@DA@GO@M and disperse it at high speed for 1.0 h at a rotation speed of 1000 r / min;

[0122] (3) Add the sheet-like filler, bulk filler and rust-preventive filler, adjust the rotation speed to 1000 r / min, and disperse evenly;

[0123] (4) Add thickener and disperse at 1000 r / min at high speed until the fineness is ≤80 μm;

[0124] (5) Add waterborne epoxy resin emulsion A, waterborne epoxy resin emulsion B, and defoamer, and disperse at 1000 r / min for 15 min;

[0125] (6) Filter and package to obtain component A as the finished product.

[0126] The preparation method of component B is as follows:

[0127] Add deionized water, regulator, pH adjuster, anti-flash rust agent and water-based epoxy curing agent, start stirring, adjust the speed to 500 r / min, disperse evenly, filter and package to obtain component B finished product.

[0128] Among them, EP@DA@GO@M in Examples 1-3 were self-made, and their preparation process is as follows:

[0129] a. Add deionized water to dilute commercially available water-based graphene (GO) slurry a (brand name GRF-FLGAD) with a mass content of 10% to a pure graphene mass content of 0.5%, and disperse at high speed of 2000 rpm for 1.5 h to obtain graphene slurry b.

[0130] b. In a four-necked flask, turn on the magnetic stirrer and cooling water, adjust the speed to 1500 rpm, slowly add 1.0 g dopamine, 100 ml deionized water and 1.5 g 1,6-hexanediol diglycidyl ether, add 0.002 g catalyst K54, heat to 45 °C, disperse at high speed of 1500 rpm until dopamine is completely dissolved, and then continue to disperse for 2 h.

[0131] Weigh 200g of graphene slurry b and add it to a four-necked flask. Adjust the temperature to 30℃ and disperse at high speed for 24h. Filter by suction, wash with anhydrous ethanol and filter by suction 3-5 times, then bake in an oven at 80℃ for 5h to obtain EP@DA@GO.

[0132] c. Dissolve 2-mercaptobenzimidazole (M) in anhydrous ethanol to form a 10% mass content solution M(aq). Then add 1% mass content of silane coupling agent KH-560 to this aqueous solution, denoted as KM(aq), for later use.

[0133] d. Weigh 10g of EP@DA@GO, add 100ml of deionized water, and disperse at 1500rpm for 1.5h; weigh 50g of KM(aq) and add it to the system, adjust the temperature of the four-necked flask to 40℃, turn on the cooling water, and continue to disperse for 2.0h.

[0134] e. Filter, wash 3-5 times with deionized water, and place in a 60℃ oven for 6 hours to obtain the nanocomposite material EP@DA@GO@M.

[0135] 2. Comparative Examples 1-5

[0136] The raw material selection and coating preparation methods of Comparative Examples 1-5 are the same as those of Example 1. The only difference between them and Example 1 is the nanocomposite material EP@DA@GO@M, specifically:

[0137] Comparative Example 1: No nanocomposite material EP@DA@GO@M added.

[0138] Comparative Example 2 used aqueous graphene (GO) slurry, 2-mercaptobenzimidazole, dopamine, and 1,6-hexanediol diglycidyl ether to directly replace the nanocomposite material EP@DA@GO@M in Example 1.

[0139] Comparative Example 3 uses 2-mercaptobenzimidazole and EP@DA@GO directly added to replace the nanocomposite material EP@DA@GO@M in Example 1; the only difference between the preparation process of EP@DA@GO and the preparation process of EP@DA@GO@M in Example 1 is that 2-mercaptobenzimidazole is not added.

[0140] Comparative Example 4 uses 1,6-hexanediol diglycidyl ether and DA@GO@M directly added to replace the nanocomposite material EP@DA@GO@M in Example 1; the only difference between the preparation process of DA@GO@M and the preparation process of EP@DA@GO@M in Example 1 is that 1,6-hexanediol diglycidyl ether was not added.

[0141] Comparative Example 5 uses aqueous graphene (GO) slurry and EP@DA@M directly added to replace the nanocomposite material EP@DA@GO@M in Example 1; the only difference between the preparation process of EP@DA@M and the preparation process of EP@DA@GO@M in Example 1 is that the aqueous graphene (GO) slurry is not added.

[0142] 3. Comparative Example 6

[0143] Existing waterborne epoxy coatings are prepared according to a mass ratio of component A to component B of 9:1.

[0144] The performance of components A and B in Example 1 (mass ratio) was tested at an A:B ratio of 5:1, in Example 2 at an A:B ratio of 6.5:1, in Example 3 at an A:B ratio of 7.8:1, and in Comparative Examples 1-4 at an A:B ratio of 5:1. The test results are shown in Table 3.

[0145] Table 3

[0146]

[0147] Analyzing the above test results, we can see that:

[0148] As can be seen from Examples 1-3 in Table 4, the coating prepared by the present invention has excellent salt spray resistance and salt water resistance;

[0149] Comparing the data from Examples 1-3 and Comparative Examples 1-5, it can be seen that the addition of the nanocomposite material EP@DA@GO@M significantly improved the salt spray resistance, 3.5% NaCl immersion resistance, and electrochemical impedance of the waterborne epoxy coating, resulting in a significant enhancement in corrosion resistance. The main reason for this is:

[0150] The nanocomposite material EP@DA@GO@M possesses dual functions of "chemical slow release and physical shielding" and exhibits curing reactivity, which can improve the crosslinking density of the coating. Specifically, the EP@DA resin, modified with 1,6-hexanediol diglycidyl ether, exhibits good dispersibility with epoxy resin, excellent coordination with GO, and good chemical reactivity with the curing agent. The GO modified with EP@DA is well dispersed in the system, effectively blocking the penetration of corrosive media. Simultaneously, the EP@DA@GO loaded with the corrosion inhibitor 2-mercaptobenzimidazole M effectively passivates the substrate and significantly increases the crosslinking density of the coating, thus achieving a triple effect of chemical slow release, physical shielding, and enhanced crosslinking density.

[0151] As can be seen from Examples 1-3 and Comparative Example 1, the corrosion resistance of waterborne epoxy coatings without the addition of nanocomposite material EP@DA@GO@M is significantly reduced, indicating that the nanocomposite material EP@DA@GO@M does indeed play a triple protective role of "chemical slow release-physical shielding" and increased crosslinking density.

[0152] As can be seen from Examples 1-3 and Comparative Example 2, the improvement in the corrosion resistance of the coating is not significant after adding DA, GO, M and 1,6-hexanediol diglycidyl ether alone. This indicates that the excellent corrosion resistance of the nanocomposite material EP@DA@GO@M prepared in this invention is the result of the coordination of multiple technologies, and ordinary physical mixing cannot achieve its corrosion resistance effect.

[0153] As can be seen from Examples 1-3 and Comparative Example 3, EP@DA@GO and the slow-release agent M also exerted a synergistic effect after modification and loading. After preparing them into nanocomposite materials EP@DA@GO@M, the present invention simultaneously improved the dispersibility of GO and the slow-release performance of M. This effect is greater than the effect of ordinary physical mixing of EP@DA@GO and M.

[0154] As can be seen from Examples 1-3 and Comparative Example 4, the chemical modification of DA by 1,6-hexanediol diglycidyl ether in the early stage is crucial. Without this step, the corrosion resistance of the coating cannot be significantly improved. This indicates that only the composite material EP@DA@GO@M modified by 1,6-hexanediol diglycidyl ether possesses triple corrosion resistance. The modification of DA by 1,6-hexanediol diglycidyl ether lays the foundation for the chemical reactivity and good dispersibility of the composite material, changing the EP@DA@GO@M composite material from a dual-function particle of chemical rust prevention and physical shielding to a triple-function particle with reactivity, greatly improving the corrosion resistance of the coating.

[0155] As can be seen from Examples 1-3 and Comparative Example 5, compared with the coating with added EP@DA@GO@M, the coating with EP@DA@M and GO added directly without GO modification has a certain decrease in corrosion resistance. This indicates that EP@DA@GO@M has a good physical shielding effect, and the modification technology used in this invention can effectively improve the dispersibility of GO in the coating.

[0156] In summary, the coating exhibits excellent corrosion resistance thanks to the synergistic effect of the preparation technology and formulation design of the nanocomposite material EP@DA@GO@M of this invention. This achieves the goal of highly efficient corrosion protection for water-based epoxy anti-rust paint. The absence of any one component or technology would significantly reduce its overall performance. Therefore, the inventive effect of this invention is achieved through the synergistic effect of various raw materials, rather than simply by adding them together, demonstrating significant innovation.

[0157] The technical solution of this invention includes at least the following design concepts, novelty, and beneficial effects:

[0158] The main design concept of this invention:

[0159] (1) Dopamine was modified by 1,6-hexanediol diglycidyl ether. The modified dopamine was then reacted with graphene (GO) to introduce catechol groups and epoxy groups on the GO surface. The nanocomposite material EP@DA@GO@M was prepared by using the hydrogen bonding and electronic coupling between the -OH in the catechol group, the -OH and -NH- in the modified dopamine and the NH and C=N in 2-mercaptobenzimidazole (M).

[0160] The technical features are as follows:

[0161] 1) First, the molar ratio of 1,6-hexanediol diglycidyl ether to dopamine is controlled at 0.8:1 to 1.2:1. Under the catalysis of K54, the -NH2 group in dopamine undergoes an addition reaction with the epoxy group in 1,6-hexanediol diglycidyl ether to generate hexanediol diglycidyl ether modified dopamine epoxy resin. This modified dopamine epoxy resin is a bifunctional compound, with an epoxy group at one end and a dopamine structure at the other, while fully retaining the dopamine-catechol structure. This modified dopamine epoxy resin EP@DA, due to its epoxy group and catechol structure, exhibits excellent compatibility with epoxy resins such as 5175 and 2060H.

[0162] The structural formula of the catechol group is as follows:

[0163] ;

[0164] The structural formula of the epoxy group is as follows:

[0165] .

[0166] 2) The catechol hydroxyl, -NH-, and -OH groups in the modified dopamine epoxy resin interact with the -OH and -COOH groups in the modified graphene through coordination and hydrogen bonding to form the dopamine epoxy resin modified graphene material EP@DA@GO.

[0167] 3) In the complete catechol structure of EP@DA@GO, the phenol-OH group can form a multifunctional PDA@GO@M nanocomposite material through hydrogen bonding and electronic coordination with the -SH, N=H, C=N, and benzene rings of 2-mercaptobenzimidazole (M). This composite material retains the sustained-release function of 2-mercaptobenzimidazole (M) to the greatest extent. The -SH group, as an adsorption active sustained-release site, can freely desorb from the composite material under corrosive acidic conditions, achieving a sustained-release effect on the substrate and improving the corrosion resistance of the coating.

[0168] (2) The nanocomposite material EP@DA@GO@M has both chemical and physical rust prevention effects. 2-Mercaptobenzimidazole (M) in EP@DA@GO@M is an environmentally friendly bio-based corrosion inhibitor with chemical rust prevention effect, while graphene material is a high aspect ratio sheet barrier material that can effectively block the penetration of corrosive media. This invention effectively synergizes the chemical rust prevention effect of the bio-based slow-release agent and the physical rust prevention effect of the graphene material, effectively improving the corrosion resistance of the water-based epoxy coating.

[0169] (3) By using dopamine-modified epoxy resin EP@DA to modify GO, catechol groups, epoxy groups and long carbon chain structures are introduced on the surface of GO. Through the similarity between the catechol groups, epoxy groups and the structure of bisphenol A epoxy resin, and the interaction between the phenolic hydroxyl groups in the catechol groups and the hydroxyl groups and ether bonds in the epoxy resin, the dispersibility of graphene in the epoxy resin system can be effectively improved, graphene agglomeration can be avoided, and the shielding properties of graphene can be improved. At the same time, for the nanocomposite EP@DA@GO@M, the epoxy groups and catechol groups in its structure also greatly improve the dispersibility of the composite material in the coating, effectively improving its "shielding-slow release" dual effect, thereby improving the coating life.

[0170] (4) The nanocomposite material EP@DA@GO@M prepared in this invention not only has chemical slow release and physical shielding effects, but is also a functional resin with chemical reactivity. The epoxy groups in the composite material can react chemically with the active -NH2 in the curing agent, which on the one hand increases the crosslinking density of the coating, and on the other hand, the mutual electronic interaction between the epoxy groups in EP@DA@GO@M and -NH2 can further enhance the uniform dispersion of the composite filler in the coating, thereby improving its slow release and shielding effects. The synergistic effect of these factors effectively improves the corrosion resistance of the waterborne epoxy coating.

[0171] (5) Coating formulation design of the present invention: Through multiple technologies such as formulation PVC (pigment volume concentration) optimization, multiple shielding effects of physical anti-rust fillers, and control of film-forming material crosslinking density, the shielding effect of the coating is effectively improved, and its protective effect on the substrate is enhanced.

[0172] In summary, the nanocomposite material EP@DA@GO@M provided by this invention, when applied to the preparation of environmentally friendly and long-lasting anti-corrosion water-based epoxy heavy-duty anti-corrosion coatings, has the following characteristics and functions:

[0173] (1) EP@DA@GO@M has a triple function of "chemical slow release-physical shielding" and reactivity;

[0174] (2) EP@DA@GO@M material can simultaneously improve the crosslinking density of waterborne epoxy coating and achieve the triple effect of physical shielding and chemical slow release synergistic anti-corrosion. It is an active composite material that effectively improves the anti-corrosion properties of waterborne epoxy coating.

[0175] (3) The electronic coordination between the catechol group, epoxy group, and -OH group in EP@DA@GO@M and the epoxy resin, and the interaction between the epoxy group in EP@DA@GO@M and the amino group of the curing agent, synergistically improve the dispersibility of EP@DA@GO@M in epoxy coating, further improve its application efficiency, and realize the long-term anti-corrosion function of waterborne epoxy coating.

[0176] (4) The raw materials for the preparation of EP@DA@GO@M, dopamine and 2-mercaptobenzimidazole, are both bio-based materials, and the coating is green and environmentally friendly.

[0177] This invention is applicable to the preparation of polydopamine-modified waterborne epoxy heavy-duty anti-corrosion coatings with slow-release function, and can be applied to corrosion protection of all steel structures.

[0178] In summary, the concept and effects of this invention can be summarized as follows:

[0179] This invention modifies dopamine with 1,6-hexanediol diglycidyl ether to generate dopamine-modified epoxy resin EP@DA. EP@DA is further modified with graphene (GO) by introducing catechol groups and epoxy groups onto the graphene surface to form EP@DA@GO nanoparticles. Simultaneously, the hydrogen bonds and electronic coordination between the phenol-OH group in catechol and 2-mercaptobenzimidazole (M) and the benzene ring are utilized to form a multifunctional EP@DA@GO@M reactive composite material, achieving the dual function of "shielding-slow release" and active reaction of the nanocomposite material.

[0180] By utilizing the similarity and compatibility between the catechol groups, epoxy groups, and -OH groups in the EP@DA@GO@M composite material and epoxy resin, and the synergistic interaction between the epoxy groups in EP@DA@GO@M and the amino groups in the curing agent, the dispersibility of the composite material in the coating system is effectively solved. Furthermore, by utilizing the reactivity of the active epoxy groups in the EP@DA@GO@M composite material and the amino groups in the curing agent, the crosslinking density of the coating is further increased while ensuring that the composite material has both chemical and physical anti-corrosion functions. At the same time, through synergistic formulation design optimization, the high-efficiency anti-corrosion performance of the waterborne epoxy coating is finally achieved, which is significantly innovative.

[0181] It should be noted that:

[0182] In this article, “~” is used to represent the range of values, and the range of values ​​represented by this expression includes two endpoint values.

[0183] The specific parameters or commonly used reagents in the above embodiments are specific or preferred embodiments under the concept of this invention, and are not intended to limit it; those skilled in the art can make adaptive adjustments within the concept and protection scope of this invention. Furthermore, unless otherwise specified, the raw materials used can also be commercially available products in the art, or prepared by conventional methods in the art.

[0184] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0185] Although this document frequently uses terms such as functional filler and polyaspartic acid ester, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the description and claims of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0186] Finally, 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 foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a nanocomposite material EP@DA@GO@M, characterized in that, Includes the following steps: Aqueous graphene slurry a was diluted with water to a graphene mass content of (0.3-0.7)% to obtain graphene slurry b; Under reflux, dopamine, catalyst, water and 1,6-hexanediol diglycidyl ether were mixed and heated to (40-50) °C and stirred to dissolve dopamine. The mixture was then dispersed for (2-2.5) h to form a mixed solution C. Graphene slurry b was added to mixed solution C and stirred and dispersed at (25-35)℃ for (20-24) h. The product was then filtered, washed, and dried to obtain the composite material EP@DA@GO. A silane coupling agent was added to an anhydrous ethanol solution of 2-mercaptobenzimidazole to obtain a mixture KM; After mixing EP@DA@GO, water and KM, the system was heated to 35℃~45℃ and refluxed for 1.5~2.0h. The product was then filtered, washed and dried to obtain the nanocomposite material EP@DA@GO@M.

2. The method for preparing the nanocomposite material EP@DA@GO@M according to claim 1, characterized in that... The mass ratio of dopamine, catalyst, 1,6-hexanediol diglycidyl ether, and graphene slurry b is (1.0–1.5):(0.002–0.006):(1.5–1.75):(180–220). The catalyst used is catalyst K54.

3. The method for preparing the nanocomposite material EP@DA@GO@M according to claim 1, characterized in that... In the preparation of the KM mixture, the mass content of the 2-mercaptobenzimidazole anhydrous ethanol solution is (8-15)%; the amount of the silane coupling agent used is (1-1.5)% of the mass of the 2-mercaptobenzimidazole anhydrous ethanol solution. The silane coupling agent is KH-560.

4. The method for preparing the nanocomposite material EP@DA@GO@M according to claim 1, characterized in that... In the preparation process of EP@DA@GO@M, the mass ratio of EP@DA@GO to KM is 10:(30-50).

5. The method for preparing the nanocomposite material EP@DA@GO@M according to claim 1, characterized in that... : In the preparation process of EP@DA@GO, the reaction product is filtered and the residue is washed with anhydrous ethanol 3 to 5 times, and then dried at (70 to 90) °C for (5 to 6) h to obtain EP@DA@GO; In the preparation process of EP@DA@GO@M, the reaction product is filtered, and the residue is washed with water 3 to 5 times. Then, it is dried at (55 to 65) °C for (6 to 8) h to obtain EP@DA@GO@M.

6. A nanocomposite material EP@DA@GO@M, characterized in that: The nanocomposite material was prepared using the method described in any one of claims 1-5.

7. A water-based epoxy heavy-duty anti-corrosion coating with slow-release function, comprising component A and component B, characterized in that: The component A comprises the nanocomposite material EP@DA@GO@M as described in claim 6.

8. The waterborne epoxy heavy-duty anti-corrosion coating with slow-release function according to claim 7, characterized in that... By weight, component A comprises: 10-25 parts water, 0.1-1 parts dispersant, 0.1-1 parts substrate wetting agent, 5-10 parts cosolvent, 0.1-1 parts defoamer, 5-10 parts nanocomposite material EP@DA@GO@M, 5-15 parts flake filler, 5-15 parts extender filler, 10-30 parts rust-inhibiting filler, 0.1-2.0 parts thickener, 5-15 parts waterborne epoxy resin emulsion A, and 10-30 parts waterborne epoxy resin emulsion B; By weight, component B comprises: 5-10 parts water, 0.1-1.5 parts pH adjuster, 0.1-1.5 parts flash rust inhibitor, and 80-99 parts water-based epoxy curing agent; The weight ratio of component A to component B is (5-8):

1.

9. The waterborne epoxy heavy-duty anti-corrosion coating with slow-release function according to claim 8, characterized in that... The dispersant is one or more combinations of BYK-190, BYK-151, and COATEXP90; And / or, the substrate wetting agent is one or more combinations of BYK-348, Hydropalat 140, and Tego wet 270; And / or, the co-solvent is a mixture of propylene glycol methyl ether and diethylene glycol butyl ether in a mass ratio of 5:3; And / or, the defoamer is one or more combinations of NXZ, Foamex 830, Surfynol 104E, and Tego 450; And / or, the sheet-like filler is sericite powder; And / or, the bulk filler is one or more combinations of barite powder, titanium dioxide, and precipitated barium sulfate; And / or, the rust-preventive filler is one or more combinations of zinc phosphate, composite nano-iron-titanium powder, and aluminum tripolyphosphate; And / or, the thickener is one or more combinations of BR-125P, WT-105A, and WT-204; And / or, the aqueous epoxy resin emulsion A is E51 type epoxy emulsion 5175; And / or, the aqueous epoxy resin emulsion B is E20 type epoxy emulsion 2060H; And / or, the pH adjuster is one or a combination of two of DMEA and AMP-95; And / or, the flash rust inhibitor is FA-179; And / or, the waterborne epoxy curing agent is a mixture of KEH-305 and BC901 in a mass ratio of 1:

3.

10. A method for preparing a waterborne epoxy heavy-duty anti-corrosion coating with slow-release function as described in any one of claims 8-9, characterized in that: The preparation process of component A is as follows: Disperse the water, dispersant, substrate wetting agent, cosolvent and defoamer evenly; Then, the nanocomposite material EP@DA@GO@M is added and dispersed evenly. Then add the sheet filler, bulk filler, and rust-inhibiting filler and disperse them evenly; Then add a thickener and disperse at high speed until the fineness is ≤80μm; Finally, add waterborne epoxy resin emulsion A, waterborne epoxy resin emulsion B, and defoamer, disperse evenly, and filter to obtain component A; The preparation process of component B is as follows: The components B are obtained by dispersing water, regulator, pH adjuster, anti-flash rust agent and water-based epoxy curing agent evenly and filtering.

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