Preparation process of heavy-duty anticorrosive coating for building bridges

Abstract

The application relates to the field of corrosion prevention technology, and particularly relates to a preparation process of heavy-duty anticorrosive paint for building bridges, which introduces a self-repairing prepolymer into water-based epoxy resin as a base material to improve the durability, uses composite basalt flakes as fillers, introduces diluents and penetrants as assistants under the action of a water-based amine curing agent, grows nanometer silicon dioxide on the surface of the basalt flakes in situ to obtain pretreated basalt flakes, and then grafts 2-urea-based-4[1H] pyrimidone; the self-repairing prepolymer is a silicone-modified prepolymer grafted with composite phenylboronic acid ester; the composite phenylboronic acid ester is obtained by a thiol-ene click reaction of eugenol and 3-mercapto-1,2-propanediol to obtain double-hydroxyl eugenol, and then grafted with 2-urea-based-4[1H] pyrimidone under the action of boron-nitrogen coordination between 2-dimethylaminoethylamine and 3-aminophenylboronic acid to form phenylboronic acid ester with pH response by dehydration.

Description

Technical Field

[0001] This invention relates to the field of corrosion protection technology, specifically a preparation process for heavy-duty anti-corrosion coatings for building bridges. Background Technology

[0002] With rapid economic development, the increasing number of bridge and building projects has effectively improved transportation capacity and provided convenience for modern people's travel and life. However, during construction and use, bridges are inevitably subject to corrosion and damage due to factors such as materials used, environment, temperature, drying shrinkage, and maintenance conditions. This accelerates structural deterioration and affects their safety. Therefore, strengthening corrosion protection for bridges is of great significance for maintaining their long-term operational safety and stability.

[0003] Bridge coatings have seen widespread use in recent years due to their advantages such as lightweight, aesthetic appeal, economy, and ease of application. Bridge anti-corrosion coatings are generally divided into conventional and heavy-duty anti-corrosion coatings. Heavy-duty anti-corrosion coatings are designed for use in relatively harsh corrosive environments and offer a longer protection period compared to conventional coatings. With the promotion of environmental protection concepts, environmentally friendly coating products are constantly being introduced to the market. Among them, water-based coatings are currently a rapidly developing type of environmentally friendly coating. However, the difficulty of application and limited durability of thick-film heavy-duty anti-corrosion coatings have restricted their development and promotion. Summary of the Invention

[0004] The purpose of this invention is to provide a preparation process for heavy-duty anti-corrosion coatings for building bridges, so as to solve the problems in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A heavy-duty anti-corrosion coating for building bridges comprises two components, A and B. By weight, component A comprises 21-31 parts of waterborne epoxy resin, 14-24 parts of self-healing prepolymer, 5-10 parts of diluent, and 1-5 parts of composite basalt flakes; component B comprises 1-3 parts of waterborne amine curing agent and 1-3 parts of penetrant.

[0007] Furthermore, the diluent is one or more of the following: butanediol diglycidyl ether, polypropylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, and cashew phenol glycidyl ether.

[0008] Furthermore, the penetrant is one or a combination of sodium butylnaphthalenesulfonate and acetylenol polyoxyethylene ether.

[0009] Furthermore, the water-based amine curing agent is one or more of the following: ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, diethylenetriamine, tetraethylenepentamine, and trimethylhexanediamine.

[0010] Furthermore, the preparation of the self-healing prepolymer includes the following steps:

[0011] (1) Under a nitrogen atmosphere, polytetrahydrofuran glycol, polypropylene glycol, hydroxyl-terminated polydimethylsiloxane and dibutyltin dilaurate are mixed, heated to 105℃ and kept at that temperature for 1h, cooled to 18-25℃ and added isophorone diisocyanate, heated to 78-82℃ and kept at that temperature for 2-3h to obtain organosilicon modified prepolymer;

[0012] (2) Mix the organosilicon-modified prepolymer and tetrahydrofuran, add the composite phenylboronic acid ester and dibutyltin dilaurate, stir for 20-30 minutes, and discharge to obtain the self-healing prepolymer.

[0013] Furthermore, the mass ratio of the organosilicon-modified prepolymer to the composite phenylboronic acid ester is 9:2.

[0014] Furthermore, the preparation of the composite phenylboronic ester includes the following steps:

[0015] 1) Under a nitrogen atmosphere, eugenol, 3-mercapto-1,2-propanediol, 2-hydroxy-2-methylphenylacetone and tetrahydrofuran were mixed and irradiated under 360 nm ultraviolet light for 10 h to obtain dihydroxyeugenol;

[0016] 2) Mix dihydroxyeugenol, 3-aminophenylboronic acid, 2-dimethylaminoethylamine and tetrahydrofuran, add anhydrous sodium sulfate and stir for 10-12 h, centrifuge and filter, add 2-ureido-4[1H]pyrimidinone, and continue to keep warm for 22-24 h to obtain composite phenylboronic acid ester.

[0017] Furthermore, the preparation of composite basalt flakes includes the following steps:

[0018] A. Mix basalt flakes, tetraethyl silicate, and anhydrous ethanol, add ammonia, keep warm at 78-82℃ for 4-5 hours, cool, wash with anhydrous ethanol 3-5 times, filter, and dry to obtain pretreated basalt flakes.

[0019] B. Under a nitrogen atmosphere, 2-ureido-4[1H]pyrimidinone and N,N-dimethylformamide are mixed, heated to 78-82℃ and kept at that temperature for 1-2 hours, dibutyltin dilaurate is added, pretreated basalt flakes are added, and the mixture is kept at that temperature for 7-8 hours. After cooling, the mixture is filtered, washed, and dried to obtain composite basalt flakes.

[0020] Furthermore, the preparation of 2-ureido-4[1H]pyrimidinone includes the following steps: under nitrogen protection, hexamethylene diisocyanate and 2-amino-4-hydroxy-6-methylpyrimidin are mixed, heated to 98-102℃ and kept at that temperature for 22-24h, cooled, washed with ether 3-5 times, and dried to obtain 2-ureido-4[1H]pyrimidinone.

[0021] Furthermore, a method for preparing a heavy-duty anti-corrosion coating for building bridges includes the following steps:

[0022] S1: Mix water-based epoxy resin, self-healing polyurea prepolymer, diluent, and composite basalt flakes to obtain component A;

[0023] S2: Mix water-based amine curing agent and penetrant to obtain component B; mix component A and component B to obtain a heavy-duty anti-corrosion coating for building bridges.

[0024] The beneficial effects of this invention are:

[0025] This invention provides a preparation process for heavy-duty anti-corrosion coatings for building bridges. Through component design, the prepared heavy-duty anti-corrosion coating forms a coating with a self-healing surface and has durable hydrophobicity, impact resistance, and corrosion resistance.

[0026] To address the common problems of easy peeling and limited lifespan of epoxy anti-corrosion coatings in the existing market, this invention uses waterborne epoxy resin as the base material and introduces a self-healing prepolymer to improve its durability. Composite basalt flakes are used as fillers, and diluents and penetrants are introduced as additives under the action of waterborne amine curing agents. This significantly improves the coating's hardness, impact resistance, and other mechanical strengths, while also enhancing its bonding strength with the substrate, forming a hydrophobic self-healing surface. This endows the heavy-duty anti-corrosion coating with durable resistance to mechanical damage, thereby providing long-lasting protection for buildings and bridges.

[0027] Using environmentally friendly and inexpensive basalt flakes as filler, a "maze effect" is generated in water-based epoxy resin, thereby improving the corrosion resistance of the coating. However, the interfacial properties between basalt flakes and water-based epoxy resin are weak, and direct addition to the coating can easily lead to uneven dispersion, thus affecting its protective performance. At the same time, there are gaps between the flakes. To solve this problem, this invention utilizes the hydroxyl groups on the surface of basalt flakes to grow nano-silica in situ on the surface of basalt flakes, obtaining pretreated basalt flakes, thereby constructing a micro-nano structure and improving the layering of protection. By reacting the hydroxyl groups on the pretreated basalt flakes with the isocyanate groups of 2-ureido-4[1H]pyrimidinone, which has four hydrogen bonds, 2-ureido-4[1H]pyrimidinone, prepared by the reaction of hexamethylene diisocyanate and 2-amino-4-hydroxy-6-methylpyrimidinone, is grafted onto the pretreated basalt flakes, giving the coating the ability to self-repair even at low temperatures, thereby significantly improving the coating hardness and impact resistance.

[0028] The self-healing prepolymer is prepared by using polytetrahydrofuran glycol, polypropylene glycol, hydroxyl-terminated polydimethylsiloxane, and isophorone diisocyanate as raw materials, and obtaining an organosilicon-modified prepolymer under the catalysis of dibutyltin dilaurate. Then, a composite phenylboronic acid ester is grafted onto it as a capping agent. The mass limits of polytetrahydrofuran glycol, polypropylene glycol, and hydroxyl-terminated polydimethylsiloxane impart good impact resistance to the self-healing prepolymer. The composite phenylboronic acid ester is prepared by using eugenol, a natural antifouling agent, as a raw material, and 3-mercapto-phenylboronic acid ester... 1,2-propanediol undergoes a mercapto-olefin click reaction to yield dihydroxyeugenol. Under the boron-nitrogen coordination between 2-dimethylaminoethylamine and 3-aminophenylboronic acid, it is dehydrated to form a pH-responsive phenylboronic ester. Then, 2-ureido-4[1H]pyrimidinone isocyanate groups are grafted onto it to obtain a self-healing prepolymer with multiple active sites, thereby enhancing the adhesion performance of the coating, solving the problem of easy breakage and peeling of traditional coatings, and significantly increasing the fatigue life and self-healing properties of the coating formed by the coating. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indicators such as up, down, left, right, front, and back, these directional indicators are only used to explain the relative positional relationship and movement of components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0031] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1: A method for preparing a heavy-duty anti-corrosion coating for building bridges, comprising the following steps:

[0033] S1: Mix water-based epoxy resin, self-healing polyurea prepolymer, diluent, and composite basalt flakes to obtain component A;

[0034] By weight, component A comprises 21 parts of waterborne epoxy resin, 14 parts of self-healing prepolymer, 5 parts of diluent, and 1 part of composite basalt flakes; component B comprises 1 part of waterborne amine curing agent and 1 part of penetrant.

[0035] The diluent is polypropylene glycol diglycidyl ether; the penetrant is sodium butylnaphthalene sulfonate;

[0036] The aqueous amine curing agent is tetraethylenepentamine;

[0037] The preparation of the self-healing prepolymer includes the following steps:

[0038] (1) Under a nitrogen atmosphere, 8g of polytetrahydrofuran glycol, 10g of polypropylene glycol, 2g of hydroxyl-terminated polydimethylsiloxane and 0.02g of dibutyltin dilaurate were mixed, heated to 105℃ and kept at that temperature for 1h, cooled to 18℃ and 14g of isophorone diisocyanate were added, and the temperature was raised to 78℃ and kept at that temperature for 3h to obtain an organosilicon modified prepolymer;

[0039] (2) Mix 9g of organosilicon-modified prepolymer and 45mL of tetrahydrofuran, add 2g of composite phenylboronic acid ester and 0.1g of dibutyltin dilaurate, stir for 20min to obtain self-healing prepolymer;

[0040] The preparation of the composite phenylboronic ester includes the following steps:

[0041] 1) Under a nitrogen atmosphere, 4.3 g of eugenol, 2.7 g of 3-mercapto-1,2-propanediol, 0.07 g of 2-hydroxy-2-methylphenylacetone and 40 mL of tetrahydrofuran were mixed and irradiated under 360 nm ultraviolet light for 10 h to obtain dihydroxyeugenol.

[0042] 2) Mix 0.54g of dihydroxyeugenol, 0.26g of 3-aminophenylboronic acid, 0.36g of 2-dimethylaminoethylamine, and 10mL of tetrahydrofuran. Add 0.4g of anhydrous sodium sulfate and stir for 10h. Centrifuge and filter. Add 1.4g of 2-ureido-4[1H]pyrimidinone and continue to keep warm for 22h to obtain the composite phenylboronic acid ester.

[0043] The preparation of the composite basalt flakes includes the following steps:

[0044] A. Mix 4g of basalt flakes, 24mL of tetraethyl silicate, and 90mL of anhydrous ethanol, add 5mL of ammonia, keep warm at 78℃ for 5h, cool, wash 3 times with anhydrous ethanol, filter, and dry to obtain pretreated basalt flakes.

[0045] B. Under a nitrogen atmosphere, 0.1 g of 2-ureido-4[1H]pyrimidinone and 40 mL of N,N-dimethylformamide were mixed, heated to 78 °C and kept at that temperature for 2 h, 4 drops of dibutyltin dilaurate were added, 2 g of pretreated basalt flakes were added, and the mixture was kept at that temperature for 7 h. After cooling, the mixture was filtered, washed, and dried to obtain composite basalt flakes.

[0046] The preparation of the 2-ureido-4[1H]pyrimidinone includes the following steps: under nitrogen protection, 5.3 g of hexamethylene diisocyanate and 0.6 g of 2-amino-4-hydroxy-6-methylpyrimidinone are mixed, heated to 98°C and kept at that temperature for 24 h, cooled, washed three times with ether, and dried to obtain 2-ureido-4[1H]pyrimidinone;

[0047] S2: Mix water-based amine curing agent and penetrant to obtain component B; mix component A and component B to obtain a heavy-duty anti-corrosion coating for building bridges.

[0048] Example 2: A method for preparing a heavy-duty anti-corrosion coating for building bridges, comprising the following steps:

[0049] S1: Mix water-based epoxy resin, self-healing polyurea prepolymer, diluent, and composite basalt flakes to obtain component A;

[0050] By weight, component A comprises 25 parts of waterborne epoxy resin, 18 parts of self-healing prepolymer, 6 parts of diluent, and 3 parts of composite basalt flakes; component B comprises 2 parts of waterborne amine curing agent and 2 parts of penetrant.

[0051] The diluent is benzyl glycidyl ether; the penetrant is sodium butylnaphthalene sulfonate; and the aqueous amine curing agent is tetraethylenepentamine.

[0052] The preparation of the self-healing prepolymer includes the following steps:

[0053] (1) Under a nitrogen atmosphere, 8g of polytetrahydrofuran glycol, 10g of polypropylene glycol, 2g of hydroxyl-terminated polydimethylsiloxane and 0.02g of dibutyltin dilaurate were mixed, heated to 105℃ and kept at that temperature for 1h, cooled to 20℃ and 14g of isophorone diisocyanate were added, and the mixture was heated to 80℃ and kept at that temperature for 2.5h to obtain an organosilicon-modified prepolymer;

[0054] (2) Mix 9g of organosilicon-modified prepolymer and 45mL of tetrahydrofuran, add 2g of composite phenylboronic acid ester and 0.1g of dibutyltin dilaurate, stir for 25min to obtain self-healing prepolymer;

[0055] The preparation of the composite phenylboronic ester includes the following steps:

[0056] 1) Under a nitrogen atmosphere, 4.3 g of eugenol, 2.7 g of 3-mercapto-1,2-propanediol, 0.07 g of 2-hydroxy-2-methylphenylacetone and 40 mL of tetrahydrofuran were mixed and irradiated under 360 nm ultraviolet light for 10 h to obtain dihydroxyeugenol.

[0057] 2) Mix 0.54g of dihydroxyeugenol, 0.26g of 3-aminophenylboronic acid, 0.36g of 2-dimethylaminoethylamine, and 10mL of tetrahydrofuran, add 0.4g of anhydrous sodium sulfate and stir for 11h. Centrifuge, filter, add 1.4g of 2-ureido-4[1H]pyrimidinone, and continue to keep warm for 23h to obtain the composite phenylboronic acid ester.

[0058] The preparation of the composite basalt flakes includes the following steps:

[0059] A. Mix 4g of basalt flakes, 24mL of tetraethyl silicate, and 90mL of anhydrous ethanol, add 5mL of ammonia, keep warm at 80℃ for 4.5h, cool, wash 4 times with anhydrous ethanol, filter, and dry to obtain pretreated basalt flakes.

[0060] B. Under a nitrogen atmosphere, 0.1 g of 2-ureido-4[1H]pyrimidinone and 40 mL of N,N-dimethylformamide were mixed, heated to 80 °C and kept at that temperature for 1.5 h, 4 drops of dibutyltin dilaurate were added, 2 g of pretreated basalt flakes were added, and the mixture was kept at that temperature for 7.5 h. After cooling, the mixture was filtered, washed, and dried to obtain composite basalt flakes.

[0061] The preparation of the 2-ureido-4[1H]pyrimidinone includes the following steps: under nitrogen protection, 5.3 g of hexamethylene diisocyanate and 0.6 g of 2-amino-4-hydroxy-6-methylpyrimidinone are mixed, heated to 100°C and kept at that temperature for 23 h, cooled, washed 4 times with ether, and dried to obtain 2-ureido-4[1H]pyrimidinone;

[0062] S2: Mix water-based amine curing agent and penetrant to obtain component B; mix component A and component B to obtain a heavy-duty anti-corrosion coating for building bridges.

[0063] Example 3: A method for preparing a heavy-duty anti-corrosion coating for building bridges, comprising the following steps:

[0064] S1: Mix water-based epoxy resin, self-healing polyurea prepolymer, diluent, and composite basalt flakes to obtain component A;

[0065] By weight, component A comprises 31 parts of waterborne epoxy resin, 24 parts of self-healing prepolymer, 10 parts of diluent, and 5 parts of composite basalt flakes; component B comprises 3 parts of waterborne amine curing agent and 3 parts of penetrant.

[0066] The diluent is cashew phenol glycidyl ether; the penetrant is sodium butylnaphthalene sulfonate; and the aqueous amine curing agent is tetraethylenepentamine.

[0067] The preparation of the self-healing prepolymer includes the following steps:

[0068] (1) Under a nitrogen atmosphere, 8g of polytetrahydrofuran glycol, 10g of polypropylene glycol, 2g of hydroxyl-terminated polydimethylsiloxane and 0.02g of dibutyltin dilaurate were mixed, heated to 105℃ and kept at that temperature for 1h, cooled to 25℃ and 14g of isophorone diisocyanate were added, and the temperature was raised to 82℃ and kept at that temperature for 2h to obtain an organosilicon-modified prepolymer;

[0069] (2) Mix 9g of organosilicon-modified prepolymer and 45mL of tetrahydrofuran, add 2g of composite phenylboronic acid ester and 0.1g of dibutyltin dilaurate, stir for 30min to obtain self-healing prepolymer;

[0070] The preparation of the composite phenylboronic ester includes the following steps:

[0071] 1) Under a nitrogen atmosphere, 4.3 g of eugenol, 2.7 g of 3-mercapto-1,2-propanediol, 0.07 g of 2-hydroxy-2-methylphenylacetone and 40 mL of tetrahydrofuran were mixed and irradiated under 360 nm ultraviolet light for 10 h to obtain dihydroxyeugenol.

[0072] 2) Mix 0.54g of dihydroxyeugenol, 0.26g of 3-aminophenylboronic acid, 0.36g of 2-dimethylaminoethylamine, and 10mL of tetrahydrofuran. Add 0.4g of anhydrous sodium sulfate and stir for 12h. Centrifuge and filter. Add 1.4g of 2-ureido-4[1H]pyrimidinone and continue to keep warm for 24h to obtain the composite phenylboronic acid ester.

[0073] The preparation of the composite basalt flakes includes the following steps:

[0074] A. Mix 4g of basalt flakes, 24mL of tetraethyl silicate, and 90mL of anhydrous ethanol, add 5mL of ammonia, keep warm at 82℃ for 4h, cool, wash 5 times with anhydrous ethanol, filter, and dry to obtain pretreated basalt flakes.

[0075] B. Under a nitrogen atmosphere, 0.1 g of 2-ureido-4[1H]pyrimidinone and 40 mL of N,N-dimethylformamide were mixed, heated to 82 °C and kept at that temperature for 1 h, 4 drops of dibutyltin dilaurate were added, 2 g of pretreated basalt flakes were added, and the mixture was kept at that temperature for 7-8 h. After cooling, the mixture was filtered, washed, and dried to obtain composite basalt flakes.

[0076] The preparation of the 2-ureido-4[1H]pyrimidinone includes the following steps: under nitrogen protection, 5.3 g of hexamethylene diisocyanate and 0.6 g of 2-amino-4-hydroxy-6-methylpyrimidinone are mixed, heated to 102 °C and kept at that temperature for 22 h, cooled, washed 5 times with ether, and dried to obtain 2-ureido-4[1H]pyrimidinone;

[0077] S2: Mix water-based amine curing agent and penetrant to obtain component B; mix component A and component B to obtain a heavy-duty anti-corrosion coating for building bridges.

[0078] Comparative Example 1: Example 3 was used as the control group. Pretreated basalt flakes were used to replace composite basalt flakes, while other processes were normal.

[0079] Comparative Example 2: Using Example 3 as the control group, the self-healing prepolymer was replaced with an organosilicon-modified prepolymer, while other processes were normal.

[0080] Comparative Example 3: Using Example 3 as the control group, 2-ureido-4[1H]pyrimidinone was not prepared, and other processes were normal.

[0081] Source of raw materials (for illustrative purposes only):

[0082] Waterborne epoxy resin 001: Langfang Wanteng Anticorrosion Materials Co., Ltd.; Cashew phenol glycidyl ether 171263-25-5: Hubei Jusheng Technology Co., Ltd.; 3-Aminophenylboronic acid S30813, sodium butylnaphthalenesulfonate S63838: Shanghai Yuanye Biotechnology Co., Ltd.; 3-Mercapto-1,2-propanediol 96-27-5: Hubei Yongkuo Technology Co., Ltd.; Basalt flakes (250 mesh): Haining Anjie Composite Materials Co., Ltd.; Polypropylene glycol diglycidyl ether P135604, benzyl glycidyl ether P136148, tetraethylenepentamine T103795, polytetrahydrofurandiol P117874, polypropylene glycol P1032 09. Hydroxyl-terminated polydimethylsiloxane P304442, dibutyltin dilaurate D100274, isophorone diisocyanate I109582, tetrahydrofuran T103263, eugenol E110640, 2-hydroxy-2-methylphenylacetone H110280, 2-dimethylaminoethylamine D105347, hexamethylene diisocyanate H106723, 2-amino-4-hydroxy-6-methylpyrimidine A151322, N,N-dimethylformamide D111999, tetraethyl silicate T110593: Aladdin reagent; anhydrous ethanol, anhydrous sodium sulfate, ammonia, and ether, analytical grade: Sinopharm Group reagent.

[0083] Performance testing: The coatings prepared in the examples and comparative examples were applied to a Q345B steel plate with dimensions of 150mm × 70mm × 0.5mm, and the resulting coating thickness was 0.5mm.

[0084] Water contact angle: Tested using a contact angle meter, using a 2μL deionized water droplet;

[0085] Low-temperature self-healing property: A scratch measuring 1 mm in length, 4 μm in width, and 250 μm in depth was formed on the coating. After incubation at 0℃ for 12 hours, the scratch length was observed under an electron microscope. The self-healing rate = (L... 初始划痕长度 -L 现有划痕长度 ) / L 初始划痕长度 ×100%;

[0086] Adhesion: Draw a 100-grid grid with equal spacing on the coating surface, expose the substrate through the scratches, apply tape and remove the tape at a uniform speed. Grade 0 - no edge peeling, Grade 1 - cross-damaged area less than 5%, Grade 2 - cross-damaged area less than 15%, Grade 3 - cross-damaged area less than 35%.

[0087] Impact resistance: The test is conducted in accordance with GB / T1732-2020. The distance between the impact part of the test plate and the edge is 15mm, and the distance between the boundaries of each impact point is 15mm. The weight is fixed at 50cm. The paint film is observed under a 4x magnifying glass for cracks, wrinkles and leakage. If there are any, it is unqualified; if there are none, it is excellent.

[0088] Corrosion resistance: Salt spray resistance was tested according to GB / T1771-2007. The salt spray chamber temperature was 37℃, the sodium chloride concentration was 55g / L, and the pH value was 7. After 3000h, blistering, peeling, and corrosion were observed. If they appeared, it was considered unqualified; if not, it was considered excellent. The results are shown in Table 1 below.

[0089] Table 1

[0090]

[0091]

[0092] This invention provides a preparation process for heavy-duty anti-corrosion coatings for building bridges. Through component design, the prepared heavy-duty anti-corrosion coating forms a coating with a self-healing surface and has durable hydrophobicity, impact resistance, and corrosion resistance.

[0093] Comparing Example 3 with Comparative Example 1, it can be seen that using environmentally friendly and inexpensive basalt flakes as a filler creates a "maze effect" in water-based epoxy resin, thereby improving the corrosion resistance of the coating. However, basalt flakes and water-based epoxy resin have weak interfacial properties, and direct addition to the coating can lead to uneven dispersion, thus affecting its protective performance. Furthermore, gaps exist between the flakes. To address this issue, this invention utilizes the hydroxyl groups on the surface of basalt flakes to grow nanoparticles in situ on the surface of the basalt flakes. Pretreated basalt flakes were obtained by using silica to construct micro-nano structures and improve the layering of protection. The hydroxyl groups on the pretreated basalt flakes were reacted with the isocyanate groups of 2-ureido-4[1H]pyrimidinone, which has four hydrogen bonds, to graft 2-ureido-4[1H]pyrimidinone, which was prepared by reacting hexamethylene diisocyanate and 2-amino-4-hydroxy-6-methylpyrimidine, onto the pretreated basalt flakes. This gave the coating the ability to self-repair even at low temperatures, thereby greatly improving the coating's hardness and impact resistance.

[0094] Comparing Example 3 with Comparative Examples 2 and 3, it can be seen that the self-healing prepolymer is prepared by using polytetrahydrofuran glycol, polypropylene glycol, hydroxyl-terminated polydimethylsiloxane, and isophorone diisocyanate as raw materials, and obtaining an organosilicon-modified prepolymer under the catalysis of dibutyltin dilaurate. Then, a composite phenylboronic acid ester is grafted onto it as a capping agent. The mass limits of polytetrahydrofuran glycol, polypropylene glycol, and hydroxyl-terminated polydimethylsiloxane impart good impact resistance to the self-healing prepolymer. The composite phenylboronic acid ester is a natural antifouling agent. Eugenol is used as a raw material and reacts with 3-mercapto-1,2-propanediol in a mercapto-olefin click reaction to obtain dihydroxyeugenol. Under the boron-nitrogen coordination between 2-dimethylaminoethylamine and 3-aminophenylboronic acid, it is dehydrated to form a pH-responsive phenylboronic ester. Then, 2-ureido-4[1H]pyrimidinone isocyanate groups are grafted onto it to obtain a self-healing prepolymer with multiple active sites, thereby enhancing the adhesion performance of the coating, solving the problem of easy breakage and peeling of traditional coatings, and greatly increasing the fatigue life and self-healing properties of the coating formed by the coating.

[0095] The heavy-duty anti-corrosion coating for building bridges prepared by this invention has high corrosion resistance and good self-healing properties, making up for the shortcomings of existing commercially available products in terms of limited service life.

[0096] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the present invention's specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A heavy-duty anti-corrosion coating for building bridges, characterized in that, It consists of two components, A and B. By weight, component A includes 21-31 parts of waterborne epoxy resin, 14-24 parts of self-healing prepolymer, 5-10 parts of diluent, and 1-5 parts of composite basalt flakes; component B includes 1-3 parts of waterborne amine curing agent and 1-3 parts of penetrant. The preparation of the self-healing prepolymer includes the following steps: (1) Under a nitrogen atmosphere, polytetrahydrofuran glycol, polypropylene glycol, hydroxyl-terminated polydimethylsiloxane and dibutyltin dilaurate are mixed, heated to 105℃ and kept at that temperature for 1h, cooled to 18-25℃ and added isophorone diisocyanate, heated to 78-82℃ and kept at that temperature for 2-3h to obtain organosilicon modified prepolymer; (2) Mix the organosilicon-modified prepolymer and tetrahydrofuran, add the composite phenylboronic acid ester and dibutyltin dilaurate, stir for 20-30 min, and discharge to obtain the self-healing prepolymer; The preparation of the composite phenylboronic ester includes the following steps: 1) Under a nitrogen atmosphere, eugenol, 3-mercapto-1,2-propanediol, 2-hydroxy-2-methylphenylacetone and tetrahydrofuran were mixed and irradiated under 360 nm ultraviolet light for 10 h to obtain dihydroxyeugenol; 2) Mix dihydroxyeugenol, 3-aminophenylboronic acid, 2-dimethylaminoethylamine and tetrahydrofuran, add anhydrous sodium sulfate and stir for 10-12 h, centrifuge and filter, add 2-ureido-4[1H]pyrimidinone, and continue to keep warm for 22-24 h to obtain composite phenylboronic acid ester. The preparation of the composite basalt flakes includes the following steps: A. Mix basalt flakes, tetraethyl silicate, and anhydrous ethanol, add ammonia, keep warm at 78-82℃ for 4-5 hours, cool, wash with anhydrous ethanol 3-5 times, filter, and dry to obtain pretreated basalt flakes. B. Under a nitrogen atmosphere, 2-ureido-4[1H]pyrimidinone and N,N-dimethylformamide are mixed, heated to 78-82℃ and kept at that temperature for 1-2 hours, dibutyltin dilaurate is added, pretreated basalt flakes are added, and the mixture is kept at that temperature for 7-8 hours. After cooling, the mixture is filtered, washed, and dried to obtain composite basalt flakes.

2. The heavy-duty anti-corrosion coating for building bridges according to claim 1, characterized in that, The diluent is one or more of the following: butanediol diglycidyl ether, polypropylene glycol diglycidyl ether, benzyl glycidyl ether, phenyl glycidyl ether, and cashew phenol glycidyl ether.

3. The heavy-duty anti-corrosion coating for building bridges according to claim 1, characterized in that, The penetrant is one or a combination of sodium butylnaphthalenesulfonate and acetylacetonate diol polyoxyethylene ether.

4. The heavy-duty anti-corrosion coating for building bridges according to claim 1, characterized in that, The aqueous amine curing agent is one or more of the following: ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, and trimethylhexamethylenediamine.

5. The heavy-duty anti-corrosion coating for building bridges according to claim 1, characterized in that, In the preparation of the self-healing prepolymer, the mass ratio of the organosilicon-modified prepolymer to the composite phenylboronic acid ester is 9:

2.

6. The heavy-duty anti-corrosion coating for building bridges according to claim 1, characterized in that, The preparation of the 2-ureido-4[1H]pyrimidinone includes the following steps: under nitrogen protection, hexamethylene diisocyanate and 2-amino-4-hydroxy-6-methylpyrimidin are mixed, heated to 98-102℃ and kept at that temperature for 22-24h, cooled, washed with ether 3-5 times, and dried to obtain 2-ureido-4[1H]pyrimidinone.

7. A method for preparing a heavy-duty anti-corrosion coating for building bridges according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Mix waterborne epoxy resin, self-healing prepolymer, diluent, and composite basalt flakes to obtain component A; S2: Mix water-based amine curing agent and penetrant to obtain component B; mix component A and component B to obtain a heavy-duty anti-corrosion coating for building bridges.

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