Salt-spray-resistant water-based industrial paint and preparation method thereof

Abstract

The invention relates to the technical field of industrial paint, in particular to salt-spray-resistant water-based industrial paint and a preparation method thereof.The salt-spray-resistant water-based industrial paint comprises a component A and a component B. The mass ratio of the component A to the component B is (12-15): 1. The component A comprises cationic water-based epoxy resin, water-based acrylic acid modified epoxy resin, a pH regulator, an ampholytic surfactant, mica powder and nano-zinc oxide; a silane coupling agent, polyether modified siloxane, a wetting dispersant and deionized water are added; the component B is prepared from the following components: a polyamide epoxy curing agent, 2-ethyl-4-methylimidazole, propylene glycol methyl ether acetate and deionized water. By compounding the cationic water-borne epoxy resin and the water-borne acrylic acid modified epoxy resin, the weather resistance is improved while excellent salt fog resistance is maintained, and the water-borne epoxy resin composition is suitable for rust prevention of metal surfaces.

Description

Technical Field

[0001] The invention relates to the technical field of industrial coatings, in particular to a salt spray resistant water-based industrial paint and a preparation method thereof. Background Art

[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 curing agents or diluents. It is a new type of environmentally friendly anti-rust and anti-corrosion coating that is different from oil-based industrial paint.

[0003] A Chinese invention with publication number CN116694188B discloses a high-performance water-based epoxy resin emulsion, its preparation method, and application. The invention uses bisphenol A epoxy resin as the base resin. The molecular structure of the bisphenol A epoxy resin contains aromatic ether bonds. The aromatic ether bonds will degrade and break under the irradiation of solar ultraviolet rays, causing the cured epoxy resin product to lose gloss and gradually become powdery, resulting in poor weather resistance and light resistance of the epoxy resin. Summary of the Invention

[0004] The object of the present invention is to provide a salt spray resistant water-based industrial paint and a preparation method thereof, so as to solve the problems raised in the above background technology.

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

[0006] The preparation method of the cationic waterborne epoxy resin comprises the following steps: S1, adding 1.0 mol of 1,4-cyclohexanedimethanol and 0.01 mol of tetrabutylammonium bromide to a reactor protected by nitrogen, heating to 50° C., uniformly adding 2.0 mol of epichlorohydrin dropwise within 1 hour, keeping the temperature for reaction for 1 hour, cooling to 40° C., adding a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions, keeping the temperature for reaction for 4 hours, adding 100 mL of toluene, 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 under nitrogen, Under nitrogen protection, the temperature is raised to 80°C and 0.05 mol of benzyltrimethylammonium chloride is slowly added, the temperature is kept for reaction for 4 hours, and the reduced pressure degassing is carried out at 10 kPa and 80°C for 2 hours to obtain an epoxy-terminated prepolymer; S3, the epoxy-terminated prepolymer is heated to 85°C, 0.6 mol of monoglycidyl ether-terminated PDMS is slowly added, the reaction is carried out under nitrogen protection for 4 hours, the volatile matter is removed by reduced pressure distillation at 80°C for 30 minutes, and the modified polymer is obtained by filtering; S4, 0.2 mol of benzoic acid is slowly added to the modified polymer, deionized water is slowly added while stirring at 1000 rpm, emulsified for 30 minutes, and 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, and the mass ratio of cocamidopropyl betaine to Tween 80 is 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 dripping speed 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. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reaction kettle, adjust the pH to 8.5-9.0 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 20-30 min. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 200-400 rpm for 20-30 min to obtain component A.

[0016] S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 1800-2400 rpm for 30-60 min, and cool to room temperature to obtain component B;

[0017] S3. Mixing: Evenly mix component A and component B to prepare the salt spray resistant water-based industrial paint.

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

[0019] 1. The present invention improves weather resistance while maintaining excellent salt spray resistance by compounding a cationic waterborne epoxy resin and a waterborne acrylic acid-modified epoxy resin, making it suitable for rust prevention on metal surfaces.

[0020] 2. The present invention prevents cationic waterborne epoxy resin from demulsifying by using a pH regulator, and solves the compatibility problem between ionic waterborne epoxy resin and waterborne acrylic acid-modified epoxy resin through charge neutralization and steric hindrance by using an amphoteric surfactant, thereby improving storage stability. The amphoteric surfactant forms an oriented arrangement layer at the interface, which helps to block chloride ion penetration and improve the salt spray resistance of the product. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

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

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

[0024] S1. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reaction kettle, adjust the pH to 8.5 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 20 min. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 200 rpm for 20 min to obtain component A.

[0025] S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 1800 rpm for 30 min, and cool to room temperature to obtain component B;

[0026] S3. Mixing: Evenly mix component A and component B to prepare salt spray resistant water-based industrial paint.

[0027] Example 2: The present invention provides a salt spray-resistant water-based 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 of a cationic water-based epoxy resin, 20 parts of a water-based acrylic-modified epoxy resin, 0.1 part of a pH adjuster, 0.8 parts of an amphoteric surfactant, 10 parts of mica powder, 4 parts of nano-zinc oxide, 1 part of a silane coupling agent, 0.5 parts of a polyether-modified siloxane, 0.7 parts of a wetting and dispersing agent, and 12 parts of deionized water. Component B comprises the following components, by weight: 18 parts of a polyamide epoxy curing agent, 3 parts of 2-ethyl-4-methylimidazole, 4 parts of propylene glycol methyl ether acetate, and 12 parts of deionized water.

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

[0029] S1. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reaction kettle, adjust the pH to 8.7 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 25 minutes. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 300 rpm for 25 minutes to obtain component A.

[0030] S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 2000 rpm for 45 minutes, and cool to room temperature to obtain component B;

[0031] S3. Mixing: Evenly mix component A and component B to prepare salt spray resistant water-based industrial paint.

[0032] Example 3: The present invention provides a salt spray-resistant water-based 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 of a cationic water-based epoxy resin, 20 parts of a water-based acrylic acid-modified epoxy resin, 0.3 parts of a pH adjuster, 1.0 parts of an amphoteric surfactant, 12 parts of mica powder, 5 parts of nano-zinc oxide, 2 parts of a silane coupling agent, 0.6 parts of a polyether-modified siloxane, 0.8 parts of a wetting and dispersing agent, and 15 parts of deionized water. Component B comprises the following components, by weight: 20 parts of a polyamide epoxy curing agent, 5 parts of 2-ethyl-4-methylimidazole, 5 parts of propylene glycol methyl ether acetate, and 15 parts of deionized water.

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

[0034] S1. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reactor, adjust the pH to 9.0 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 30 min. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 400 rpm for 30 min to obtain component A.

[0035] S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 2400 rpm for 60 min, and cool to room temperature to obtain component B;

[0036] S3. Mixing: Evenly mix component A and component B to prepare salt spray resistant water-based industrial paint.

[0037] Example 4: The present invention provides a salt spray-resistant water-based 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 of a cationic water-based epoxy resin, 20 parts of a water-based acrylic acid-modified epoxy resin, 0.2 parts of a pH adjuster, 0.7 parts of an amphoteric surfactant, 10 parts of mica powder, 4 parts of nano-zinc oxide, 1 part of a silane coupling agent, 0.5 parts of a polyether-modified siloxane, 0.7 parts of a wetting and dispersing agent, and 14 parts of deionized water. Component B comprises the following components, by weight: 16 parts of a polyamide epoxy curing agent, 4 parts of 2-ethyl-4-methylimidazole, 4 parts of propylene glycol methyl ether acetate, and 12 parts of deionized water.

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

[0039] S1. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reactor, adjust the pH to 8.8 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 25 min. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 300 rpm for 25 min to obtain component A.

[0040] S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 2200 rpm for 50 min, and cool to room temperature to obtain component B;

[0041] S3. Mixing: Evenly mix component A and component B to prepare salt spray resistant water-based industrial paint.

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

[0043] S1. Add 1.0 mol of 1,4-cyclohexanedimethanol and 0.01 mol of tetrabutylammonium bromide to a nitrogen-protected reactor, heat to 50°C, and uniformly add 2.0 mol of epichlorohydrin dropwise within 1 hour. Keep the temperature for reaction for 1 hour. Cool to 40°C, and add a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions. Keep the temperature for reaction for 4 hours. Add 100 mL of toluene, and azeotropically dehydrate at 50 kPa and 80°C for 1 hour. Filter to obtain an epoxidation intermediate, wherein the 5% w / w aqueous solution containing 2.2 mol of NaOH is prepared by diluting 2.2 mol of NaOH into a 5% w / w aqueous solution. The addition rate of the 5% w / w aqueous solution containing 2.2 mol of NaOH is 3-4 mL / min.

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

[0045] S3. The epoxy-terminated prepolymer was heated to 85° C., 0.6 mol of monoglycidyl ether-terminated PDMS was slowly added, and the mixture was reacted for 4 h under nitrogen protection. Volatiles were removed by reduced pressure distillation at 80° C. for 30 min, and the mixture was filtered to obtain a modified polymer, wherein the molecular weight of the monoglycidyl ether-terminated PDMS was 1000-1200;

[0046] S4. Slowly add 0.2 mol of benzoic acid to the modified polymer, slowly add deionized water while stirring at 1000 rpm, emulsify for 30 minutes, and filter to 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 to 4, the pH regulator is AMP-95, the amphoteric surfactant is a combination of cocamidopropyl betaine and Tween 80, the mass ratio of cocamidopropyl betaine to Tween 80 is 2:1, the average particle size of the mica powder is 25 μm, and the silane coupling agent is silane coupling agent KH-570.

[0048] The wetting and dispersing agents in Example 1 and Example 2 are Disper BYK101 and Disper BYK130 respectively, and the wetting and dispersing agents in Example 3 and Example 4 are both Disper BYK160.

[0049] Test Example 1

[0050] Test content: According to the method disclosed in HG / T 3668-2020, the paint film performance test was carried out on the salt spray resistant water-based industrial paints prepared in Examples 1 to 4. The test substrate size was 150mm×70mm×5mm, and the coating thickness was 100μm. Before application, the A component and the B component 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 time after the salt spray test, the corrosion spread width at the scratch is maintained at ≤2.0mm, and the unscratched area does not rust, crack, or peel.

[0051] Test 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 in Test Example 1 were tested for powdering degree and cracking grade. The results are recorded in Table 1.

[0053] Table 1

[0054]

[0055] Among them, the powdering degree of level 0 means no powdering, the cracking quantity level of level 0 means no visible cracking, and the cracking size level of level S0 means no visible cracking under a 10x magnifying glass.

[0056] As can be seen from 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 which Example 4 performs the best and is worthy of promotion and use.

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

Claims

1. A salt spray resistant water-based industrial paint, characterized in that: The invention comprises component A and component B in a mass ratio of (12-15):1, wherein the component A comprises the following components in parts by weight: 80 parts of a cationic waterborne epoxy resin, 20 parts of a waterborne acrylic acid-modified epoxy resin, 0.1-0.3 parts of a pH regulator, 0.5-1.0 parts of an amphoteric surfactant, 8-12 parts of mica powder, 3-5 parts of nano zinc oxide, 1-2 parts of a silane coupling agent, 0.4-0.6 parts of a polyether-modified siloxane, 0.5-0.8 parts of a wetting and dispersing agent, and 10-15 parts of deionized water; and the component B comprises the following components in parts by weight: 15-20 parts of a polyamide epoxy curing agent, 1-5 parts of 2-ethyl-4-methylimidazole, 3-5 parts of propylene glycol methyl ether acetate, and 10-15 parts of deionized water. The preparation method of the cationic waterborne epoxy resin comprises the following steps: S1, adding 1.0 mol of 1,4-cyclohexanedimethanol and 0.01 mol of tetrabutylammonium bromide to a reactor protected by nitrogen, heating to 50° C., uniformly adding 2.0 mol of epichlorohydrin dropwise within 1 hour, keeping the temperature for reaction for 1 hour, cooling to 40° C., adding a 5% w / w aqueous solution containing 2.2 mol of NaOH in four portions, keeping the temperature for reaction for 4 hours, adding 100 mL of toluene, 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 under nitrogen, Under nitrogen protection, the temperature is raised to 80°C and 0.05 mol of benzyltrimethylammonium chloride is slowly added, the temperature is kept for reaction for 4 hours, and the reduced pressure degassing is carried out at 10 kPa and 80°C for 2 hours to obtain an epoxy-terminated prepolymer; S3, the epoxy-terminated prepolymer is heated to 85°C, 0.6 mol of monoglycidyl ether-terminated PDMS is slowly added, the reaction is carried out under nitrogen protection for 4 hours, the volatile matter is removed by reduced pressure distillation at 80°C for 30 minutes, and the modified polymer is obtained by filtering; S4, 0.2 mol of benzoic acid is slowly added to the modified polymer, deionized water is slowly added while stirring at 1000 rpm, emulsified for 30 minutes, and 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 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.

3. The salt spray resistant water-based industrial paint according to claim 1, characterized in that: The pH adjuster was 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, and the mass ratio of cocamidopropyl betaine to Tween 80 is 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 speed 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: The following steps are involved: S1. Prepare component A: pre-mix a cationic waterborne epoxy resin and deionized water in a reaction kettle, adjust the pH to 8.5-9.0 with a pH adjuster, slowly add an amphoteric surfactant, and stir for 20-30 min. Then, add a wetting dispersant, mica powder, nano zinc oxide, a silane coupling agent, and a polyether-modified siloxane, and stir continuously at a stirring speed of 200-400 rpm for 20-30 min to obtain component A. S2. Prepare component B: pre-mix 2-ethyl-4-methylimidazole and deionized water in a high-speed shear emulsifier, add polyamide epoxy curing agent and propylene glycol methyl ether acetate, stir continuously at a stirring speed of 1800-2400 rpm for 30-60 min, and cool to room temperature to obtain component B; S3. Mixing: Evenly mix component A and component B to prepare the salt spray resistant water-based industrial paint.

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