Salt-fog resistant waterborne industrial paint and preparation method thereof

Abstract

The application relates to the technical field of industrial coatings, in particular to a salt-fog-resistant water-based industrial paint and a preparation method thereof. The salt-fog-resistant water-based industrial paint comprises components A and B with a mass ratio of (12-15):1. The component A comprises the following components: a cationic water-based epoxy resin, a water-based acrylic modified epoxy resin, a pH regulator, an amphoteric surfactant, mica powder, nano zinc oxide, a silane coupling agent, a polyether modified siloxane, a wet dispersant and deionized water. The component B comprises the following components: a polyamide epoxy curing agent, 2-ethyl-4-methyl imidazole, propylene glycol methyl ether acetate and deionized water. The cationic water-based epoxy resin and the water-based acrylic modified epoxy resin are compounded, the salt-fog resistance is maintained, the weather resistance is improved, and the salt-fog-resistant water-based industrial paint is suitable for rust prevention on a metal surface.

Description

Technical Field

[0001] This invention relates to the field of industrial coatings technology, specifically to a salt spray resistant water-based industrial paint and its preparation method. Background Technology

[0002] Water-based industrial paint is a new type of environmentally friendly anti-rust and anti-corrosion coating. It uses water as a diluent and does not require the addition of additional hardeners or diluents, making it a new type of environmentally friendly anti-rust and anti-corrosion coating that is different from oil-based industrial paint.

[0003] Chinese invention patent CN116694188B discloses a high-performance waterborne epoxy resin emulsion, its preparation method, and its application. The invention uses bisphenol A epoxy resin as the base resin. The molecular structure of bisphenol A epoxy resin contains aromatic ether bonds. These aromatic ether bonds will degrade and break under the irradiation of ultraviolet rays from the sun, causing the epoxy resin to lose its gloss and gradually become powdery after curing, resulting in poor weather resistance and light resistance of the epoxy resin. Summary of the Invention

[0004] The purpose of this invention is to provide a salt spray resistant water-based industrial paint and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a salt spray resistant waterborne industrial paint and its preparation method, comprising component A and component B in a mass ratio of (12-15):1. Component A comprises, by weight, the following components: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic modified epoxy resin, 0.1-0.3 parts pH adjuster, 0.5-1.0 parts amphoteric surfactant, 8-12 parts mica powder, 3-5 parts nano zinc oxide, 1-2 parts silane coupling agent, 0.4-0.6 parts polyether modified siloxane, 0.5-0.8 parts wetting and dispersing agent, and 10-15 parts deionized water. Component B comprises, by weight, the following components: 15-20 parts polyamide epoxy curing agent, 1-5 parts 2-ethyl-4-methylimidazolium, 3-5 parts propylene glycol methyl ether acetate, and 10-15 parts deionized water.

[0006] The preparation method of the cationic waterborne epoxy resin includes the following steps: S1, adding 1.0 mol of 1,4-cyclohexanediethanol and 0.01 mol of tetrabutylammonium bromide to a nitrogen-protected reactor, heating to 50°C, and then uniformly adding 2.0 mol of epichlorohydrin dropwise over 1 hour, maintaining the temperature for 1 hour, cooling to 40°C, and then adding a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions, maintaining the temperature for 4 hours, adding 100 mL of toluene, and azeotropically dehydrating at 50 kPa and 80°C for 1 hour, filtering to obtain an epoxidized intermediate; S2, mixing the epoxidized intermediate, 1 mol of polypropylene glycol, and 0.002 mol of triphenylphosphine, and then reacting under nitrogen... Under nitrogen protection, the temperature was raised to 80℃ and 0.05 mol of benzyltrimethylammonium chloride was slowly added. The reaction was maintained at this temperature for 4 hours, and then degassed under reduced pressure at 10 kPa and 80℃ for 2 hours to obtain an epoxy-terminated prepolymer. S3, The epoxy-terminated prepolymer was heated to 85℃ and 0.6 mol of monoglycidyl ether-terminated PDMS was slowly added. The reaction was carried out under nitrogen protection for 4 hours, and the volatiles were removed by vacuum distillation at 80℃ for 30 minutes. The mixture was then filtered to obtain a modified polymer. S4, 0.2 mol of benzoic acid was slowly added to the modified polymer, and deionized water was slowly added while stirring at 1000 rpm. The mixture was emulsified for 30 minutes and then filtered to obtain the cationic waterborne epoxy resin emulsion.

[0007] Optionally, the solid content of the cationic waterborne epoxy resin is 60±1%, and the epoxy equivalent of the cationic waterborne epoxy resin is 505±25 g / eq.

[0008] Optionally, the pH adjuster is AMP-95.

[0009] Optionally, the amphoteric surfactant is a combination of cocamidopropyl betaine and Tween 80, with a mass ratio of cocamidopropyl betaine to Tween 80 of 2:1.

[0010] Optionally, the average particle size of the mica powder is 25 μm.

[0011] Optionally, the wetting and dispersing agent is one of Disper BYK101, Disper BYK130, and Disper BYK160.

[0012] Optionally, the dropping rate of the 5% w / w aqueous solution containing 2.2 mol NaOH is 3-4 mL / min.

[0013] Optionally, the molecular weight of the monoglycidyl ether-terminated PDMS is 1000-1200.

[0014] On the other hand, the present invention provides the following technical solution: a method for preparing a salt spray resistant water-based industrial paint, comprising the following steps:

[0015] S1. Preparation of Component A: Cationic aqueous epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 8.5-9.0 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 20-30 minutes. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 200-400 rpm for 20-30 minutes to obtain Component A.

[0016] S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water are premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate are added, and the mixture is continuously stirred at a stirring speed of 1800-2400 rpm for 30-60 min. After cooling to room temperature, component B is obtained.

[0017] S3. Mixing: Mix component A and component B thoroughly to obtain the salt spray resistant water-based industrial paint.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention combines cationic waterborne epoxy resin and waterborne acrylic modified epoxy resin, which improves weather resistance while maintaining excellent salt spray resistance, making it suitable for rust prevention on metal surfaces.

[0020] 2. This invention prevents demulsification of cationic waterborne epoxy resin by using a pH adjuster, and solves the compatibility problem between ionic waterborne epoxy resin and waterborne acrylic modified epoxy resin by using amphoteric surfactants through charge neutralization and steric hindrance, thereby improving storage stability. The amphoteric surfactants form an oriented layer at the interface, which helps to block chloride ion penetration and improve the product's salt spray resistance. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: This invention provides a salt spray resistant waterborne industrial paint, comprising component A and component B in a mass ratio of 12:1. Component A, by weight, comprises the following components: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic-modified epoxy resin, 0.1 parts pH adjuster, 0.5 parts amphoteric surfactant, 8 parts mica powder, 3 parts nano zinc oxide, 1 part silane coupling agent, 0.4 parts polyether-modified siloxane, 0.5 parts wetting and dispersing agent, and 10 parts deionized water. Component B, by weight, comprises the following components: 15 parts polyamide epoxy curing agent, 1 part 2-ethyl-4-methylimidazolium, 3 parts propylene glycol methyl ether acetate, and 10 parts deionized water.

[0023] The preparation method of the above-mentioned salt spray resistant water-based industrial paint includes the following steps:

[0024] S1. Preparation of Component A: Cationic waterborne epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 8.5 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 20 min. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 200 rpm for 20 min to obtain Component A.

[0025] S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water were premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate were added, and the mixture was continuously stirred at 1800 rpm for 30 min. After cooling to room temperature, component B was obtained.

[0026] S3. Mixing: Mix component A and component B thoroughly to obtain a salt spray resistant water-based industrial paint.

[0027] Example 2: This invention provides a salt spray resistant waterborne industrial paint, comprising component A and component B in a mass ratio of 13:1. Component A comprises the following components by weight: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic modified epoxy resin, 0.1 part pH adjuster, 0.8 parts amphoteric surfactant, 10 parts mica powder, 4 parts nano zinc oxide, 1 part silane coupling agent, 0.5 parts polyether modified siloxane, 0.7 parts wetting and dispersing agent, and 12 parts deionized water. Component B comprises the following components by weight: 18 parts polyamide epoxy curing agent, 3 parts 2-ethyl-4-methylimidazolium, 4 parts propylene glycol methyl ether acetate, and 12 parts deionized water.

[0028] The preparation method of the above-mentioned salt spray resistant water-based industrial paint includes the following steps:

[0029] S1. Preparation of Component A: Cationic waterborne epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 8.7 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 25 min. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 300 rpm for 25 min to obtain Component A.

[0030] S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water were premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate were added, and the mixture was continuously stirred at a stirring speed of 2000 rpm for 45 min. After cooling to room temperature, component B was obtained.

[0031] S3. Mixing: Mix component A and component B thoroughly to obtain a salt spray resistant water-based industrial paint.

[0032] Example 3: This invention provides a salt spray resistant waterborne industrial paint, comprising component A and component B in a mass ratio of 15:1. Component A comprises the following components by weight: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic-modified epoxy resin, 0.3 parts pH adjuster, 1.0 part amphoteric surfactant, 12 parts mica powder, 5 parts nano zinc oxide, 2 parts silane coupling agent, 0.6 parts polyether-modified siloxane, 0.8 parts wetting and dispersing agent, and 15 parts deionized water. Component B comprises the following components by weight: 20 parts polyamide epoxy curing agent, 5 parts 2-ethyl-4-methylimidazolium, 5 parts propylene glycol methyl ether acetate, and 15 parts deionized water.

[0033] The preparation method of the above-mentioned salt spray resistant water-based industrial paint includes the following steps:

[0034] S1. Preparation of Component A: Cationic waterborne epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 9.0 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 30 min. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 400 rpm for 30 min to obtain Component A.

[0035] S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water were premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate were added, and the mixture was continuously stirred at 2400 rpm for 60 min. After cooling to room temperature, component B was obtained.

[0036] S3. Mixing: Mix component A and component B thoroughly to obtain a salt spray resistant water-based industrial paint.

[0037] Example 4: This invention provides a salt spray resistant waterborne industrial paint, comprising component A and component B in a mass ratio of 14:1. Component A comprises the following components by weight: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic-modified epoxy resin, 0.2 parts pH adjuster, 0.7 parts amphoteric surfactant, 10 parts mica powder, 4 parts nano zinc oxide, 1 part silane coupling agent, 0.5 parts polyether-modified siloxane, 0.7 parts wetting and dispersing agent, and 14 parts deionized water. Component B comprises the following components by weight: 16 parts polyamide epoxy curing agent, 4 parts 2-ethyl-4-methylimidazolium, 4 parts propylene glycol methyl ether acetate, and 12 parts deionized water.

[0038] The preparation method of the above-mentioned salt spray resistant water-based industrial paint includes the following steps:

[0039] S1. Preparation of Component A: Cationic waterborne epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 8.8 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 25 min. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 300 rpm for 25 min to obtain Component A.

[0040] S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water were premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate were added, and the mixture was continuously stirred at 2200 rpm for 50 min. After cooling to room temperature, component B was obtained.

[0041] S3. Mixing: Mix component A and component B thoroughly to obtain a salt spray resistant water-based industrial paint.

[0042] In Examples 1-4, the preparation method of the cationic waterborne epoxy resin includes the following steps:

[0043] S1. Add 1.0 mol of 1,4-cyclohexanediethanol and 0.01 mol of tetrabutylammonium bromide to a nitrogen-protected reactor. After heating to 50°C, add 2.0 mol of epichlorohydrin dropwise at a uniform rate over 1 hour. Maintain the temperature for 1 hour. After cooling to 40°C, add a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions. Maintain the temperature for 4 hours. Add 100 mL of toluene and dehydrate the mixture azeotropically at 50 kPa and 80°C for 1 hour. Filter to obtain an epoxidized intermediate. The 5% w / w aqueous solution containing 2.2 mol of NaOH is obtained by diluting 2.2 mol of NaOH to a 5% w / w aqueous solution. The dropping rate of the 5% w / w aqueous solution containing 2.2 mol of NaOH is 3-4 mL / min.

[0044] S2. Mix the epoxidation intermediate, 1 mol of polypropylene glycol and 0.002 mol of triphenylphosphine, heat to 80°C under nitrogen protection and slowly add 0.05 mol of benzyltrimethylammonium chloride, keep the reaction at the temperature for 4 h, and degas under reduced pressure at 10 kPa and 80°C for 2 h to obtain the terminal epoxy prepolymer.

[0045] S3. Heat the epoxy-terminated prepolymer to 85°C, slowly add 0.6 mol of monoglycidyl ether-terminated PDMS, react under nitrogen protection for 4 h, remove volatiles by vacuum distillation at 80°C for 30 min, filter, and obtain the modified polymer, wherein the molecular weight of the monoglycidyl ether-terminated PDMS is 1000-1200.

[0046] S4. Slowly add 0.2 mol of benzoic acid to the modified polymer, and slowly add deionized water while stirring at 1000 rpm. Emulsify for 30 min, filter, and obtain a cationic waterborne epoxy resin emulsion. The solid content of the cationic waterborne epoxy resin is 60±1%, and the epoxy equivalent of the cationic waterborne epoxy resin is 505±25 g / eq.

[0047] In Examples 1-4, the pH adjuster was AMP-95, the amphoteric surfactant was a combination of cocamidopropyl betaine and Tween 80 with a mass ratio of 2:1, the average particle size of the mica powder was 25 μm, and the silane coupling agent was silane coupling agent KH-570.

[0048] The wetting and dispersing agents in Examples 1 and 2 are Disper BYK101 and Disper BYK130, respectively, while the wetting and dispersing agent in Examples 3 and 4 is Disper BYK160.

[0049] Experimental Example 1

[0050] Test Content: The salt spray resistant water-based industrial paints prepared in Examples 1-4 were subjected to film performance tests according to the method disclosed in HG / T 3668-2020. The substrate dimensions were 150mm × 70mm × 5mm, and the coating thickness was 100μm. Before application, components A and B of each salt spray resistant water-based industrial paint were mixed, diluted with pure deionized water, and the viscosity was measured using a Stormer viscometer. The test data are recorded in Table 1. Salt spray resistance refers to the duration after a salt spray test where the corrosion spread width at the scratched area is ≤2.0mm, and the unscratched area does not rust, crack, or peel.

[0051] Experimental Example 2

[0052] Test content: According to the method disclosed in GB / T 1766-2008, the salt spray resistant water-based industrial paints prepared in Examples 1 to 4 of Test Example 1 were tested for chalking degree and cracking grade, and the results are recorded in Table 1.

[0053] Table 1

[0054]

[0055] Among them, a level of 0 for the degree of pulverization indicates no pulverization, a level of 0 for the number of cracks indicates no visible cracks, and a level of S0 for the size of cracks indicates no visible cracks under a 10x magnifying glass.

[0056] As shown in Table 1, the salt spray resistant water-based industrial paints prepared in Examples 1 to 4 have excellent salt spray resistance, weather resistance and light resistance. Among them, Example 4 performs the best and is worth promoting.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A salt spray resistant water-based industrial paint, characterized in that, The product comprises component A and component B in a mass ratio of (12-15):

1. Component A, by weight, includes the following components: 80 parts cationic waterborne epoxy resin, 20 parts waterborne acrylic-modified epoxy resin, 0.1-0.3 parts pH adjuster, 0.5-1.0 parts amphoteric surfactant, 8-12 parts mica powder, 3-5 parts nano zinc oxide, 1-2 parts silane coupling agent, 0.4-0.6 parts polyether-modified siloxane, 0.5-0.8 parts wetting and dispersing agent, and 10-15 parts deionized water. Component B, by weight, includes the following components: 15-20 parts polyamide epoxy curing agent, 1-5 parts 2-ethyl-4-methylimidazolium, 3-5 parts propylene glycol methyl ether acetate, and 10-15 parts deionized water. The preparation method of the cationic waterborne epoxy resin includes the following steps: S1, adding 1.0 mol of 1,4-cyclohexanediethanol and 0.01 mol of tetrabutylammonium bromide to a nitrogen-protected reactor, heating to 50°C, and then uniformly adding 2.0 mol of epichlorohydrin dropwise over 1 hour, maintaining the temperature for 1 hour, cooling to 40°C, and then adding a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions, maintaining the temperature for 4 hours, adding 100 mL of toluene, and azeotropically dehydrating at 50 kPa and 80°C for 1 hour, filtering to obtain an epoxidized intermediate; S2, mixing the epoxidized intermediate, 1 mol of polypropylene glycol, and 0.002 mol of triphenylphosphine, and then reacting under nitrogen... Under nitrogen protection, the temperature was raised to 80℃ and 0.05 mol of benzyltrimethylammonium chloride was slowly added. The reaction was maintained at this temperature for 4 hours, and then degassed under reduced pressure at 10 kPa and 80℃ for 2 hours to obtain an epoxy-terminated prepolymer. S3, The epoxy-terminated prepolymer was heated to 85℃ and 0.6 mol of monoglycidyl ether-terminated PDMS was slowly added. The reaction was carried out under nitrogen protection for 4 hours, and the volatiles were removed by vacuum distillation at 80℃ for 30 minutes. The mixture was then filtered to obtain a modified polymer. S4, 0.2 mol of benzoic acid was slowly added to the modified polymer, and deionized water was slowly added while stirring at 1000 rpm. The mixture was emulsified for 30 minutes and then filtered to obtain the cationic waterborne epoxy resin emulsion.

2. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The cationic waterborne epoxy resin has a solid content of 60±1% and an epoxy equivalent of 505±25 g / eq.

3. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The pH adjuster is AMP-95.

4. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The amphoteric surfactant is a combination of cocamidopropyl betaine and Tween 80, with a mass ratio of cocamidopropyl betaine to Tween 80 of 2:

1.

5. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The average particle size of the mica powder is 25 μm.

6. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The wetting and dispersing agent is one of DisperBYK101, DisperBYK130, and DisperBYK160.

7. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The dropping rate of the 5% w / w aqueous solution containing 2.2 mol NaOH is 3-4 mL / min.

8. The salt spray resistant water-based industrial paint according to claim 1, characterized in that, The molecular weight of the monoglycidyl ether-terminated PDMS is 1000-1200.

9. A method for preparing a salt spray resistant water-based industrial paint according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Preparation of Component A: Cationic aqueous epoxy resin and deionized water are premixed in a reactor. The pH is adjusted to 8.5-9.0 with a pH adjuster. An amphoteric surfactant is slowly added and stirred for 20-30 minutes. Wetting and dispersing agent, mica powder, nano zinc oxide, silane coupling agent and polyether modified siloxane are added. The mixture is stirred continuously at 200-400 rpm for 20-30 minutes to obtain Component A. S2. Preparation of component B: 2-ethyl-4-methylimidazolium and deionized water are premixed in a high-speed shear emulsifier, polyamide epoxy curing agent and propylene glycol methyl ether acetate are added, and the mixture is continuously stirred at a stirring speed of 1800-2400 rpm for 30-60 min. After cooling to room temperature, component B is obtained. S3. Mixing: Mix component A and component B thoroughly to obtain the salt spray resistant water-based industrial paint.

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