A water-based epoxy resin spraying agent and its preparation method and application

Abstract

The invention discloses a water-based epoxy resin spraying agent and a preparation method and application thereof, and belongs to the field of spray film-forming water-based epoxy resin. The water-based epoxy resin spraying agent provided by the present invention is to dissolve water-based epoxy resin in a solvent as component A, and to use cyclohexanediamine carbonate and dopamine hydrochloride solution as component B. When used, component A is mixed with component B and then sprayed on the substrate surface, and an epoxy resin protective film with an anticorrosive effect is formed on the substrate surface after curing. During the curing process of the epoxy resin film, the cyclohexanediamine carbonate in component B gradually decomposes, releases carbon dioxide and cyclohexanediamine and forms an alkaline environment, and cyclohexanediamine reacts with water-based epoxy resin as a curing agent to form an epoxy resin coating, while dopamine hydrochloride polymerizes in an alkaline environment to form polydopamine, enhances the adhesion between the epoxy resin coating and the substrate, and improves the anticorrosive effect. Therefore, the water-based epoxy resin spraying agent prepared by the present invention is convenient and efficient, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the field of spray film-forming water-based epoxy resin, and in particular to a water-based epoxy resin spraying agent and a preparation method and application thereof. Background Art

[0002] Epoxy resin has excellent bonding strength, wear resistance, impact resistance, and corrosion resistance, so it is often used for metal corrosion protection. However, traditional solvent-based epoxy resin coatings are mostly diluted with organic solvents, which pollute the environment and endanger human health. Therefore, with the implementation of government policies related to environmental protection, the application of epoxy resin has been continuously transformed from solvent-based to water-based. Water-based epoxy resin coatings use water as a solvent and are mainly composed of epoxy emulsion, pigments, fillers, and additives. The coating has high hardness and is safe and environmentally friendly. Water-based epoxy resin coatings mainly use the hydrophilization of resins to make them emulsions. Because the hydrophilic groups still exist during film formation, the water resistance and corrosion resistance of the coating are poor. In addition, using traditional brushing technology, water-based epoxy resin coatings will inevitably come into contact with the human body, causing difficulties in cleaning, and traditional brushing technology is difficult to distribute the coating on heterogeneous components, small holes, gaps, and concave and convex places. Therefore, it is necessary to develop a water-based epoxy resin spray with strong adhesion, good anti-corrosion effect, low environmental pollution, and easy operation. Summary of the invention

[0003] In order to solve the above problems in the prior art, the present invention provides a water-based epoxy resin spraying agent, which can make up for the shortcomings of a single system and improve the ease of use during the construction process.

[0004] In order to achieve the above object, the present invention is implemented through the following technologies.

[0005] The water-based epoxy resin spray provided by the present invention comprises a component A and a component B which are mixed when used, and the preparation method comprises the following steps:

[0006] 1) Carbon dioxide is introduced into water under low temperature and high pressure conditions to generate carbonic acid.

[0007] 2) Dissolve the carbonic acid generated in step 1) in dichloromethane, stir evenly, add an organic base to adjust the pH of the system, stir evenly, then add EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride) and HOBT (1-hydroxybenzotriazole), place in an ice-water bath at about -20°C, cool and stir for 1 hour.

[0008] 3) Add cyclohexanediamine to the solution in step 2), stir and react for 30 minutes at room temperature, then wash with water and dry to obtain cyclohexanediamine carbonate.

[0009] 4) The cyclohexanediamine carbonate prepared in step 3) is prepared into an aqueous solution with a mass concentration of 4-6%, and a dopamine hydrochloride aqueous solution with a mass concentration of 4-6% is added thereto, and stirred evenly at room temperature. The resulting solution is component B.

[0010] 5) When in use, add water-based epoxy resin into the solvent, the mass concentration of the water-based epoxy resin is 50%-70%, and obtain component A.

[0011] Furthermore, in step 1), the low temperature and high pressure conditions are specifically: 0-5°C, 15-20MPa.

[0012] Furthermore, in step 2), HOBT is used as an acylating agent, EDCI is used to activate the carboxyl group, and the specific temperature range of about minus 20°C is minus 15°C-25°C.

[0013] Furthermore, in step 2), the organic base is one or more of triethylamine, pyridine, sodium tert-butoxide, and potassium tert-butoxide, and the organic base is added to adjust the pH of the system to 8-9.

[0014] Furthermore, in step 4), the mass ratio of the cyclohexanediamine carbonate solution to the dopamine hydrochloride solution is (1-1.5): (1-1.5).

[0015] Furthermore, the waterborne epoxy resin in step 5) can be selected from E51 and E44 types, and the solvent can be one or more of ethylene carbonate, propylene carbonate, and dimethyl carbonate.

[0016] Furthermore, in step 5), the mass ratio of component A:component B is (1-1.5):(1-1.5).

[0017] The water-based epoxy resin spraying agent provided by the present invention has a specific application method as follows:

[0018] Evenly mix components A and B to prepare a water-based epoxy resin spray. Directly spray the spray onto the substrate to be sprayed and let stand for 20-30 minutes. Repeat the aforementioned spraying and standing steps 2-3 times.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The water-based epoxy spraying agent provided by the present application is composed of a component A containing a water-based epoxy resin and a component B containing cyclohexane carbonate and dopamine hydrochloride, and the components A and B are stably present before mixing, and are sprayed onto the substrate surface in a spray form after mixing, and an epoxy resin protective film with an anticorrosive effect is formed on the substrate surface after curing. During film formation, the cyclohexane carbonate of the B component gradually decomposes, releases carbon dioxide and cyclohexane diamine and forms an alkaline environment, and cyclohexane diamine reacts with the water-based epoxy resin as a curing agent to form an epoxy resin anticorrosive layer. In addition, carbon dioxide volatilizes in the cyclohexane carbonate of the B component, and the alkaline environment produced can promote the polymerization of dopamine to form a highly adhesive polydopamine layer, increase the bonding force of the epoxy resin coating and the metal substrate, thereby improving the anticorrosive performance of the coating. The dopamine hydrochloride / cyclohexanediamine carbonate waterborne epoxy resin prepared by the present invention is coated on the base material by spraying, and a thin and uniform coating film can be obtained. For the different components, small holes, gaps, and concave and convex parts, the coating can be evenly distributed; for spraying large parts, this method is faster and more effective than brushing. The spraying construction process has the advantages of fast construction speed, high quality assurance, simple construction method, and effective reduction of environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the chemical reaction diagram for the reaction of carbonic acid and cyclohexanediamine to produce cyclohexanediamine carbonate. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The invention discloses a water-based epoxy resin spraying agent.

[0025] The preparation principle is: carbon dioxide dissolves in water to generate carbonic acid, and carbonic acid reacts with cyclohexanediamine to generate cyclohexanediamine carbonate. Cyclohexanediamine carbonate and dopamine hydrochloride are uniformly mixed at a mass ratio of 1:1 to obtain component B. Component A is a water-based epoxy resin solution. When using, component A and component B are uniformly mixed at a mass ratio of 1:1 and sprayed onto the surface of the substrate in the form of a spray.

[0026] Specifically, the present invention also specifically provides a method for preparing a water-based epoxy resin spray, comprising the following steps:

[0027] (1) Carbon dioxide is introduced into distilled water under low temperature and high pressure conditions (0-5°C, 15-20 MPa) to generate carbonic acid, wherein the molar ratio of carbon dioxide to distilled water is 1:1.

[0028] (2) The carbonic acid generated in step (1) is dissolved in dichloromethane and stirred evenly. An organic base (triethylamine, arsenic nitrate, sodium tert-butoxide, potassium tert-butoxide, etc.) is added and stirred evenly to adjust the pH of the system. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The mixture is placed in an ice-salt bath at about -15°C to 25°C, cooled and stirred for about 1 hour to complete the reaction.

[0029] (3) Add cyclohexanediamine to the solution in step (2), stir and react for 30 minutes at room temperature, then wash with water and dry to obtain cyclohexanediamine carbonate. The molar ratio of carbonic acid to cyclohexanediamine in the solution is 2:1.

[0030] (4) The cyclohexanediamine carbonate obtained in step (3) is prepared into an aqueous solution with a mass concentration of 4-6%, and a dopamine hydrochloride aqueous solution with a mass concentration of 4-6% is added thereto, and stirred evenly at room temperature. The mass ratio of the cyclohexanediamine carbonate solution to the dopamine hydrochloride solution is (1-1.5):(1-1.5), and the resulting mixture is component B.

[0031] (5) Adding water-based epoxy resin to the solvent to obtain component A. Then, A:B are uniformly mixed to obtain a water-based epoxy resin spray. The mass ratio of component A to component B is (1-1.5):(1-1.5).

[0032] (6) Spray the water-based epoxy resin spray directly onto the substrate to be coated and let it stand for 20-30 minutes.

[0033] (7) Repeat step (6) 2-3 times.

[0034] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0035] Example 1

[0036] Carbon dioxide (8.8 g) was introduced into distilled water (3.6 g) under low temperature and high pressure conditions to generate carbonic acid. Dichloromethane was used as solvent, and the generated carbonic acid was dissolved in dichloromethane, stirred evenly, and an organic base was added, stirred evenly, and the pH of the system was adjusted to 8-9 with the organic base, and then EDC (activated carboxyl group) and HOBT (acylating agent) were added, and the solution was placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Then cyclohexanediamine (11.42 g) was added to the solution, and the reaction was stirred at room temperature for 30 minutes (reaction formula as shown in FIG. Figure 1 As shown), then washed and dried to obtain cyclohexanediamine carbonate. The prepared cyclohexanediamine carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride solution (18.96g) is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (the solvent is ethylene carbonate) is component A. A:B are evenly mixed to obtain a water-based epoxy resin spray. The mass ratio of component A to component B is 1:1. After cleaning the iron substrate to be protected, directly spray the water-based epoxy resin spray and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0037] Example 2

[0038] At low temperature and high pressure, carbon dioxide (8.8 g) is introduced into distilled water (3.6 g) to generate carbonic acid. Using dichloromethane as solvent, the generated carbonic acid is dissolved in dichloromethane and stirred evenly. An organic base is added and stirred evenly. The pH of the system is adjusted to 8-9 with the organic base. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The solution is placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Cyclohexanediamine (11.42 g) is then added to the solution and stirred for 30 minutes at room temperature (reaction formula as shown below). Figure 1 As shown), then washed and dried to obtain cyclohexane carbonate. The prepared cyclohexane carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride (18.96g) solution is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (solvent is ethylene carbonate) is component A. A:B are evenly mixed to obtain a water-based epoxy resin spray. The mass ratio of component A to component B is 1:1.1. After cleaning the substrate to be protected, directly spray the water-based epoxy resin spray and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0039] Example 3

[0040] At low temperature and high pressure, carbon dioxide (8.8 g) is introduced into distilled water (3.6 g) to generate carbonic acid. Using dichloromethane as solvent, the generated carbonic acid is dissolved in dichloromethane and stirred evenly. An organic base is added and stirred evenly. The pH of the system is adjusted to 8-9 with the organic base. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The solution is placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Cyclohexanediamine (11.42 g) is then added to the solution and stirred for 30 minutes at room temperature (reaction formula as shown below). Figure 1 As shown), then washed and dried to obtain cyclohexane carbonate. The prepared cyclohexane carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride (18.96g) solution is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (solvent is ethylene carbonate) is component A. The mass ratio of component A to component B is 1:1.2. After cleaning the substrate to be protected, directly spray the water-based epoxy resin spray agent and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0041] Example 4

[0042] At low temperature and high pressure, carbon dioxide (8.8 g) is introduced into distilled water (3.6 g) to generate carbonic acid. Using dichloromethane as solvent, the generated carbonic acid is dissolved in dichloromethane and stirred evenly. An organic base is added and stirred evenly. The pH of the system is adjusted to 8-9 with the organic base. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The solution is placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Cyclohexanediamine (11.42 g) is then added to the solution and stirred for 30 minutes at room temperature (reaction formula as shown below). Figure 1 As shown), then washed and dried to obtain cyclohexane carbonate. The prepared cyclohexane carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride (18.96g) solution is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (solvent is ethylene carbonate) is component A. The mass ratio of component A to component B is 1:1.3. After cleaning the substrate to be protected, directly spray the water-based epoxy resin spray agent and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0043] Example 5

[0044] At low temperature and high pressure, carbon dioxide (8.8 g) is introduced into distilled water (3.6 g) to generate carbonic acid. Using dichloromethane as solvent, the generated carbonic acid is dissolved in dichloromethane and stirred evenly. An organic base is added and stirred evenly. The pH of the system is adjusted to 8-9 with the organic base. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The solution is placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Cyclohexanediamine (11.42 g) is then added to the solution and stirred for 30 minutes at room temperature (reaction formula as shown below). Figure 1 As shown), then washed and dried to obtain cyclohexane carbonate. The prepared cyclohexane carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride (18.96g) solution is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (solvent is ethylene carbonate) is component A. A:B are evenly mixed to obtain a water-based epoxy resin spray. The mass ratio of component A to component B is 1:1.4. After cleaning the substrate to be protected, directly spray the water-based epoxy resin spray and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0045] Example 6

[0046] At low temperature and high pressure, carbon dioxide (8.8 g) is introduced into distilled water (3.6 g) to generate carbonic acid. Using dichloromethane as solvent, the generated carbonic acid is dissolved in dichloromethane and stirred evenly. An organic base is added and stirred evenly. The pH of the system is adjusted to 8-9 with the organic base. EDC (activated carboxyl group) and HOBT (acylating agent) are then added. The solution is placed in an ice-salt bath at about -15°C-25°C, cooled and stirred for 1 hour. Cyclohexanediamine (11.42 g) is then added to the solution and stirred for 30 minutes at room temperature (reaction formula as shown below). Figure 1 As shown), then washed and dried to obtain cyclohexane carbonate. The prepared cyclohexane carbonate (20.2g) is prepared into an aqueous solution with a mass concentration of 5%, and a 5% mass concentration of dopamine hydrochloride (18.96g) solution is added thereto, and stirred evenly at room temperature. The resulting mixture is component B, and a 60% mass concentration of an aqueous epoxy resin solution (solvent is ethylene carbonate) is component A. A:B are evenly mixed to obtain a water-based epoxy resin spray. The mass ratio of component A to component B is 1:1.5. After cleaning the substrate to be protected, directly spray the water-based epoxy resin spray and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times to form an anti-corrosion epoxy resin film on the surface of the substrate.

[0047] Comparative Example:

[0048] Evenly mix cyclohexanediamine (15kg) and water-based epoxy resin solution (10kg, the solvent is ethylene carbonate), clean the iron substrate to be protected, and then directly spray the water-based epoxy resin spray agent, and let it stand for 20-30 minutes. Repeat the spraying and standing steps 2-3 times, and also test the corrosion resistance, adhesion and water absorption performance.

[0049] Example 7

[0050] Anti-corrosion performance test:

[0051] In order to characterize the corrosion resistance, adhesion and water absorption performance of the water-based epoxy resin spray of the present invention, the substrates with different anticorrosive epoxy resin films obtained in the comparative example and Examples 1-6 were immersed in a 3wt% NaCl solution at room temperature to evaluate their water absorption and adhesion levels.

[0052] GB / T10125-2012 was used as the test standard, and the coating prepared in the example was placed in a neutral salt spray tester. The test was conducted with a 3.5wt% NaCl solution, and the pH was about 7. The coating surface was scratched until the base was visible. The corrosion of the coating was recorded, and it was observed how long it took for corrosion products to appear at the scratched line of the coating.

[0053] The results are shown in Table 1.

[0054] Table 1 Test data of water-based epoxy anticorrosive spray agent for dopamine hydrochloride / cyclohexanediamine carbonate compound system

[0055] preservative Salt spray resistance / h Water absorption / % Adhesion Example 1 611 0.112 Level 1 Example 2 624 0.110 Level 1 Example 3 632 0.107 Level 1 Example 4 589 0.111 Level 1 Example 5 556 0.113 Level 1 Example 6 534 0.114 Level 1 Comparative Example 282 1.212 Level 4

[0056] As shown in Table 1, the adhesion of the water-based epoxy anticorrosive spray using the dopamine hydrochloride / cyclohexanediamine carbonate compound system is level one, and the comparative example is level four, indicating that the water-based epoxy anticorrosive spray using the dopamine hydrochloride / cyclohexanediamine carbonate compound system enhances the adhesion of the anticorrosive layer, and the water absorption rate is reduced from 1.212 to 0.112, indicating that the water-based epoxy anticorrosive spray using the dopamine hydrochloride / cyclohexanediamine carbonate compound system prepared by the present invention has good water resistance, and the corrosion resistance can reach 632h, and has good corrosion resistance.

[0057] The above content is a further detailed description of the present invention. It cannot be considered that the specific implementation modes of the present invention are limited thereto. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope determined by the claims submitted for the present invention.

Claims

1. A water-based epoxy resin spraying agent, characterized in that, include: Component A and component B are mixed when used, wherein the component A is a water-based epoxy resin solution, and the component B is a cyclohexanediamine carbonate solution and a dopamine hydrochloride solution; The preparation method of cyclohexanediamine carbonate comprises the following steps: adding an organic base to a dichloromethane solution of carbonic acid to adjust the pH of the solution to 8-9, adding EDC to activate the carboxyl group and HOBT as an acylating agent, stirring and cooling under low temperature conditions, then adding cyclohexanediamine to react, and finally washing and drying the reaction product to obtain cyclohexanediamine carbonate.

2. The water-based epoxy resin spray according to claim 1, characterized in that The solvent of the waterborne epoxy resin solution is ethylene carbonate, propylene carbonate and / or dimethyl carbonate, and the mass concentration of the waterborne epoxy resin solution is 50%-70%.

3. The water-based epoxy resin spray according to claim 1, characterized in that In the B component, the mass concentration of the cyclohexanediamine carbonate solution is 4-6% aqueous solution, the mass concentration of the dopamine hydrochloride solution is 4-6% aqueous solution, and the mass ratio of the cyclohexanediamine carbonate solution to the dopamine hydrochloride solution is (1-1.5): (1-1.5).

4. The water-based epoxy resin spray according to claim 1, characterized in that The mass ratio of the component A to the component B is (1-1.5): (1-1.5).

5. The method for preparing the water-based epoxy resin spray according to any one of claims 1 to 4, characterized in that: A water-based epoxy resin is dissolved in a solvent to obtain component A, and a cyclohexanediamine carbonate solution and a dopamine hydrochloride solution are separately prepared and mixed to obtain component B.

6. The method for preparing the water-based epoxy resin spraying agent according to claim 1, wherein: The dichloromethane solution of carbonic acid is prepared by introducing carbon dioxide into distilled water under low temperature and high pressure conditions to generate carbonic acid; and dissolving the carbonic acid in dichloromethane to obtain the dichloromethane solution of carbonic acid.

7. Use of the water-based epoxy resin spray according to any one of claims 1 to 4 for spraying a substrate surface to form a coating.

8. The use according to claim 7, characterized in that The spraying step is performed once or several times: spraying the water-based epoxy resin spray agent on the surface of the substrate and letting it stand for 20-30 minutes.

9. The use according to claim 8, characterized in that The substrate is made of metal.

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