Water-based anti-corrosion coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of water-based coatings, and discloses a water-based anticorrosive coating as well as a preparation method and application thereof. The water-based anti-corrosion coating comprises the following components in parts by mass: water-based color paste: 1-20 parts of water-based resin; 0.1 to 1.0 part of a neutralizing agent; 0.1 to 0.5 part of a thixotropic agent; 0.1 to 1 part of a flash rust inhibitor; 1-30 parts of a pigment; 1 to 20 parts of water; water-based varnish: 15 to 40 parts of water-based resin; 0.1 to 1.0 part of a neutralizing agent; 0.1 to 1 part of a drier; and 1-20 parts of water. The water-based anti-corrosion coating provided by the invention is a water-based single-component primer-topcoat quick-drying anti-corrosion coating, the water-based dispersion resin with low solvent content is selected, and the coating is low in VOC content, safe and environment-friendly; the viscosity is low, and the operability of production and construction is high; the thixotropic value of a coating system is greater than 3.2, and the one-time coating sagging film thickness of a wet film can reach 250-300 [mu] m.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based coatings, and in particular to a water-based anti-corrosion coating and a preparation method and application thereof. Background Art

[0002] In the structure of agricultural transport machinery such as tractors, the chassis, as the component closest to the ground, is subjected to harsh environmental tests. Chassis anti-corrosion coatings can be used to protect the chassis system from environmental damage, solve the problems of early rust of the chassis and coating loss, discoloration and powdering, and ensure the integrity and safety of agricultural transport machinery. Therefore, the coating quality of chassis anti-corrosion coatings is not only related to the overall appearance of agricultural transport machinery, but also to the safety performance of the machinery.

[0003] The protective coating for chassis of agricultural transport machinery abroad mainly uses deionized water-based two-component epoxy primer and water-based two-component polyurethane topcoat. The composite coating has excellent resistance to neutral salt spray and aging, but the two-coating and two-baking process results in low production efficiency, high energy consumption and high overall cost.

[0004] Domestic agricultural transport machinery chassis painting mainly chooses air-drying water-based one-component protective coatings that are affordable, easy to apply, and have the dual advantages of epoxy coatings and drying oil coatings. The existing air-drying water-based one-component protective coatings on the market generally have film-forming resins that are water-soluble resins, that is, the solvent content in the resin is 25-35%. According to the 30% formulation resin dosage, the VOC content of air-drying water-based one-component protective coatings is significantly higher than other types of water-based coatings, which has exceeded the VOC content limit of agricultural locomotive coatings in the national standard GB30981-2020 "Limits of Hazardous Substances in Industrial Protective Coatings".

[0005] In addition, in the production of modern agricultural transport machinery, the coating production line has introduced a high-pressure plunger pump centralized paint supply system and an automated coating robot to ensure the occupational health of spraying workers, improve economic benefits (such as saving paint), and improve spraying efficiency and coating quality. However, the existing water-based paint construction has insufficient adaptability. For agricultural transport machinery with a wide variety of chassis parts, complex structures, and various external dimensions, it is difficult to meet the construction requirements of the robot's stepless change of the spraying program trajectory when spraying different chassis parts. Summary of the invention

[0006] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide a water-based anti-corrosion coating; the second purpose of the present invention is to provide a method for preparing the water-based anti-corrosion coating; the third purpose of the present invention is to provide a coating; the fourth purpose of the present invention is to provide the application of the water-based anti-corrosion coating.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The first aspect of the present invention provides a water-based anti-corrosion coating, comprising the following components in parts by weight:

[0009] Water-based color paste:

[0010]

[0011] Water-based varnish:

[0012]

[0013] Preferably, the mass ratio of the aqueous color paste to the aqueous varnish is (1-3):1; further preferably, the mass ratio of the aqueous color paste to the aqueous varnish is (1-2):1.

[0014] Preferably, the water-based color paste has a slurry fineness of ≤30 μm; further preferably, the water-based color paste has a slurry fineness of ≤25 μm.

[0015] Preferably, the pH of the aqueous color paste is 8-10; further preferably, the pH of the aqueous color paste is 8.5-9.5.

[0016] Preferably, the slurry fineness of the water-based anti-corrosion coating is 10-30 μm; further preferably, the slurry fineness of the water-based anti-corrosion coating is 18-24 μm.

[0017] Preferably, in the water-based color paste or the water-based varnish, the parameters of the water-based resin include at least one of the following: pH 7-10; solid content 35-50%; solvent content 5-10%; ICI cone and plate viscometer, viscosity at 25°C is 1000-5000mPa·s; acid value ≤35mgKOH / g; Further preferably, in the water-based color paste or the water-based varnish, the parameters of the water-based resin include at least one of the following: pH 7.5-8.5; solid content 42-48%; solvent content 6-10%; ICI cone and plate viscometer, viscosity at 25°C is 1000-3000mPa·s; acid value ≤35mgKOH / g. (The solvent includes a neutralizer)

[0018] Preferably, in the water-based color paste or the water-based varnish, the water-based resin is an air-drying water-based dispersion resin; further preferably, the water-based resin includes at least one of a water-based modified epoxy ester dispersion and a water-based modified alkyd dispersion.

[0019] Preferably, the drying agent includes at least one of a Co-based drying agent, a Mn-based drying agent, a Ga-based drying agent, a Fe-based drying agent and a Zr-based drying agent; further preferably, the drying agent includes a Zr-based drying agent and a Fe-based drying agent.

[0020] Preferably, in the drying agent, the mass ratio of the Zr-based drying agent to the Fe-based drying agent is (1-6):1; further preferably, the mass ratio of the Zr-based drying agent to the Fe-based drying agent is (2-6):1.

[0021] Preferably, the aqueous color paste further comprises, by weight, 0-2.5 parts of a dispersant, 0-30 parts of a filler, and 0-0.5 parts of a defoaming agent.

[0022] Preferably, the water-based varnish further comprises, by weight, 0-0.5 parts of a defoamer, 0-1 parts of a thickener, and 0-0.5 parts of a wetting agent.

[0023] Preferably, the water-based anti-corrosion coating comprises the following components in parts by mass:

[0024] Water-based color paste: 1-20 parts of water-based resin; 0.1-1 parts of neutralizer; 0-2.5 parts of dispersant; 0.1-0.5 parts of thixotropic agent; 0.1-1 parts of anti-flash rust agent; 1-30 parts of pigment; 0-30 parts of filler; 0-0.5 parts of defoamer; 1-20 parts of water;

[0025] Water-based varnish: 15-40 parts of water-based resin; 0.1-1 parts of neutralizer; 0-0.5 parts of defoamer; 0.1-1 parts of drying agent; 0-1 parts of thickener; 0-0.5 parts of wetting agent; 1-20 parts of water.

[0026] Further preferably, the water-based anti-corrosion coating comprises the following components in parts by mass:

[0027] Water-based color paste: 5-15 parts of water-based resin; 0.1-0.5 parts of neutralizer; 0-2.0 parts of dispersant; 0.1-0.3 parts of thixotropic agent; 0.5-1 parts of anti-flash rust agent; 1-20 parts of pigment; 15-30 parts of filler; 0.1-0.3 parts of defoamer; 10-20 parts of water;

[0028] Water-based varnish: 25-40 parts of water-based resin; 0.1-0.5 parts of neutralizer; 0.1-0.5 parts of defoamer; 0.1-0.5 parts of drying agent; 0.2-1 parts of thickener; 0-0.3 parts of wetting agent; 5-15 parts of water.

[0029] More preferably, the water-based anti-corrosion coating comprises the following components in parts by mass:

[0030] Water-based color paste: 10-15 parts of water-based resin; 0.1-0.2 parts of neutralizer; 0-1.5 parts of dispersant; 0.2-0.3 parts of thixotropic agent; 0.5-1 parts of anti-flash rust agent; 5-20 parts of pigment; 15-25 parts of filler; 0.1-0.3 parts of defoamer; 15-20 parts of water;

[0031] Water-based varnish: 30-40 parts of water-based resin; 0.2-0.3 parts of neutralizer; 0.1-0.2 parts of defoamer; 0.2-0.3 parts of drying agent; 0.3-0.8 parts of thickener; 0-0.2 parts of wetting agent; 5-10 parts of water.

[0032] Preferably, in the water-based color paste and the water-based varnish, the neutralizer is independently selected from at least one of N,N-dimethylethanolamine, diethylethanolamine and 2-amino-2-methyl-1-propanol.

[0033] Preferably, the dispersant comprises a nonionic acrylic copolymer dispersant; further preferably, the dispersant comprises Gen 1252.

[0034] Preferably, the thixotropic agent includes at least one of bentonite, magnesium aluminum silicate and polyamide wax; further preferably, the thixotropic agent includes at least one of Heidis HT-W604 organic bentonite, Leifuss W2N magnesium aluminum silicate and Olochi AUNIK478 polyamide wax.

[0035] Preferably, the anti-flash rust agent includes at least one of CK-149 from Enze Chemical and FR-5100 from Puwei New Materials.

[0036] Preferably, the pigment comprises an anti-corrosion pigment and a coloring pigment.

[0037] Preferably, the anti-corrosion pigment comprises at least one of strontium phosphate, zinc phosphomolybdate and ionic anti-rust pigment; further preferably, the anti-corrosion pigment comprises zinc strontium phosphate and ionic anti-rust pigment.

[0038] Preferably, the mass ratio of the zinc strontium phosphate to the ionic anti-rust pigment is (0.1-1):1; further preferably, the mass ratio of the zinc strontium phosphate to the ionic anti-rust pigment is (0.3-0.7):1.

[0039] Preferably, the zinc strontium phosphate is zinc strontium phosphate JP-B808.

[0040] Preferably, the ionic anti-rust pigment includes at least one of silica ion exchange anti-rust pigments LMC-60, LMC-70, and calcium ion modified silica gel CH-6, CH-2.

[0041] Preferably, the coloring pigment includes at least one of carbon black, titanium white, permanent yellow, permanent red, permanent violet, phthalocyanine blue, phthalocyanine green, ultramarine, yellow iron oxide, black iron oxide, brown iron oxide and red iron oxide.

[0042] Preferably, the filler includes at least one of feldspar powder, barium sulfate, kaolin, wollastonite powder and silica powder; further preferably, the filler includes silica powder and barium sulfate.

[0043] Preferably, the particle size of the silicon micropowder and barium sulfate is 3000-5000 mesh.

[0044] Preferably, the mass ratio of the silicon micropowder to barium sulfate is (0.1-1):1; further preferably, the mass ratio of the silicon micropowder to barium sulfate is (0.2-0.8):1.

[0045] Preferably, in the water-based color paste and water-based varnish, the defoaming agent is independently selected from AFCONA-2502, BYK-1789, Evonik At least one of Foamex 845.

[0046] Preferably, the thickener comprises At least one of Gel 0630, BYK-L1400VF, and Hemmings RHEOLATE 299.

[0047] Preferably, the wetting agent includes at least one of Hesongyuan MH-44370, Innoway INSOWAY 2541, and Uka Chemical FLOW489U.

[0048] The basic principle of the present invention is described as follows:

[0049] 1) The air-drying water-based resin selected in the present invention is a water-based dispersion resin, with a solvent content (including a neutralizer) of 5-10%, a solid content of 35-50%, a pH of 7-10, an ICI cone and plate viscometer, a viscosity of 1000-5000 mPa·s at 25°C, and an acid value of ≤35 mgKOH / g; the same type of air-drying water-soluble resin has a solvent content (including a neutralizer) of 28-32%, a solid content of 65-72%, an acid value of ≤40 mgKOH / g, and an ICI cone and plate viscometer, and a viscosity of 6000-9000 mPa·s at 25°C. In comparison, the air-drying water-based dispersion resin has a low solvent (including a neutralizer) content and has the environmental advantage of low VOC; the resin has a low viscosity and high operability in production and construction; at the same time, the dispersion resin retains the characteristics of high-speed shear stability resistance of the air-drying water-soluble resin, and when applied to color paste, the water-based dispersion resin can withstand high-speed shear in the process of preparing the color paste;

[0050] 2) When the air-drying water-based dispersion resin is applied to the field of water-based coatings, during the film-forming process, the unsaturated epoxy ester group or unsaturated polyester group in the dispersion resin chain segment can produce a covalent bond with the metal substrate to form excellent adhesion, and the dispersion resin has a good wetting and wrapping effect on the pigments and fillers, which can reduce the amount of wetting agent and dispersant used, and ensure the corrosion resistance of the coating; at the same time, due to the low content of the resin co-solvent, the water-based coating prepared using the air-drying water-based dispersion resin has a high responsiveness to the thickening thixotropic agent, can be adjusted to an ideal construction viscosity, and has strong construction adaptability.

[0051] The second aspect of the present invention provides a method for preparing the water-based anti-corrosion coating according to the first aspect of the present invention, comprising the following steps:

[0052] The components of the water-based color paste are mixed to obtain the water-based color paste; the components of the water-based varnish are mixed to obtain the water-based varnish; and the water-based color paste and the water-based varnish are mixed to obtain the water-based anti-corrosion coating.

[0053] Preferably, the method for preparing the water-based anti-corrosion coating specifically comprises the following steps:

[0054] S1. Prepare water-based color paste: mix water, water-based resin, neutralizer, dispersant and anti-flash rust agent with high-speed stirring, add thixotropic agent, pigment and filler in increasing order of particle size, add defoamer, disperse evenly, grind and adjust pH to obtain the water-based color paste;

[0055] S2, preparing water-based varnish: adding water-based resin, neutralizer and water in sequence, stirring for 15-30 minutes, adding drying agent, defoamer, thickening thixotropic agent and wetting agent, stirring for 5-10 minutes, to obtain the water-based varnish;

[0056] S3, adding the water-based color paste to the water-based varnish, stirring for 15-30 minutes, filtering, and obtaining the water-based anti-corrosion coating.

[0057] The third aspect of the present invention provides a coating formed by the water-based anti-corrosion coating described in the first aspect of the present invention.

[0058] Preferably, the conditions for forming the coating include at least one of the following:

[0059] 1) The water-based anti-corrosion coating is diluted with deionized water before use;

[0060] 2) The water-based anti-corrosion coating is sprayed by a plunger pump high-pressure airless robot automated spraying system;

[0061] 3) The curing temperature of the water-based anti-corrosion coating is 50-80°C; the curing time is 20-40min.

[0062] Preferably, the diluent of the water-based anti-corrosion coating includes deionized water, and the dilution ratio is 1:(0.1-0.3).

[0063] Preferably, the curing temperature of the water-based anti-corrosion coating is 60-80°C.

[0064] Preferably, the curing time of the water-based anti-corrosion coating is 20-30 minutes.

[0065] The fourth aspect of the present invention provides the use of the water-based anti-corrosion coating described in the first aspect of the present invention in the surface coating of agricultural transportation machinery.

[0066] Preferably, the agricultural transport machine comprises an agricultural tractor.

[0067] Preferably, the surface coating of the agricultural transport machinery includes coating of the braking system, power system and transmission system in the chassis system of the agricultural transport machinery.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] 1) The water-based anti-corrosion coating provided by the present invention is a water-based single-component bottom-to-top integrated quick-drying anti-corrosion coating, which uses a water-based dispersion resin with a low solvent content, and the VOC content of the coating is less than 150g / L, which is safe and environmentally friendly; the high shear viscosity of the coating at 25°C is between 1100-1400mPa·s, the viscosity is low, and the operability of production and construction is high; the thixotropic value of the coating system is greater than 3.2, and the sagging film thickness of the wet film can reach 250-300μm after one coating;

[0070] 2) The water-based anti-corrosion coating provided by the present invention has corrosion resistance properties such as mechanical properties, water resistance and neutral salt spray resistance comparable to those of existing water-based single-component anti-corrosion coatings, and has better storage stability and drying properties. It can replace general water-based single-component anti-corrosion coatings, providing excellent corrosion resistance while improving the safety and environmental protection of coating operations;

[0071] 3) The film-forming process of the water-based anti-corrosion coating provided by the present invention is that the ester bonds in the resin react with the oxygen in the air to absorb oxygen and open-chain crosslink with the help of Co-based, Mn-based, Ga-based, Fe-based and Zr-based driers, etc. No other key components need to be added before construction. It only needs to be diluted to the construction viscosity with deionized water as a diluent and can be directly applied. There is no applicable period, and it only needs to be sealed and stored, and it can be reopened and used at any time within the shelf life;

[0072] 4) The preparation method of the water-based anti-corrosion coating provided by the present invention has simple steps, mild conditions, and is suitable for industrial use;

[0073] 5) The water-based anti-corrosion coating provided by the present invention has good construction adaptability and can be sprayed using a plunger pump high-pressure airless robot automated spraying system, which is beneficial to protecting the health of spraying workers, saving paint, improving economic benefits, and improving spraying efficiency and coating quality;

[0074] 6) The water-based anti-corrosion coating provided by the present invention can meet the application requirements of surface coating of agricultural transport machinery with a wide variety of parts, complex structures and various sizes. The VOC content of the coating meets the national standard GB 30981-2020 "Limits of Hazardous Substances in Industrial Protective Coatings" for the VOC content of agricultural locomotive coatings. It is safe and environmentally friendly and can ensure the overall appearance and safety performance of agricultural transport machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 Schematic diagram of the reaction mechanism of the film-forming process of the water-based anti-corrosion coating in an embodiment of the present invention;

[0076] Figure 2 This is a schematic diagram of the reaction mechanism of the component A resin and the component B amine curing agent of 2K waterborne epoxy coating;

[0077] Figure 3 Schematic diagram of the reaction mechanism between component A resin and component B isocyanate curing agent of 2K waterborne epoxy coating. DETAILED DESCRIPTION

[0078] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0079] The characteristic parameters of the aqueous resin WE42 water-based modified epoxy ester dispersion used in Examples 1-3 are: appearance is light yellow to light brown slightly transparent liquid; pH is 7-10; solid content is 36.5±1%; solvent (including neutralizer) content is 6-10%; ICI cone and plate viscometer, viscosity is 1000-5000mPa·s at 25°C; acid value ≤35mgKOH / g.

[0080] The characteristic parameters of the water-soluble resin 3EA31Y used in Comparative Examples 1-3 are: solvent (including neutralizer) content is 28-32%, solid content is 70±2%, acid value is ≤40mgKOH / g, ICI cone and plate viscometer, 25°C, viscosity is 6000-9000mPa·s.

[0081] Unless otherwise specified, “parts” in the following examples and comparative examples refer to “parts by mass”.

[0082] Example 1

[0083] This example prepares a water-based anti-corrosion coating, the components and contents are shown in Table 1:

[0084] Table 1 Components and contents of water-based anticorrosive coating in Example 1

[0085]

[0086]

[0087] The preparation steps of water-based anti-corrosion coating are:

[0088] S11, preparing water-based color paste: mixing water, water-based resin, neutralizer, dispersant and anti-flash rust agent with high-speed stirring, adding thixotropic agent, pigment and filler according to the particle size from small to large, adding defoamer, dispersing evenly, transferring to a sand mill, grinding until the slurry fineness is ≤25 μm, and adjusting the pH value of the color paste to 8.5-9.5, to obtain a water-based color paste;

[0089] S21. Under stirring conditions, add the water-based resin and the neutralizing agent to a stirring tank in sequence, then slowly add deionized water, stir evenly for 25 minutes, until it is stirred into a homogeneous liquid state, then add a drying agent, a defoaming agent, a thickening thixotropic agent and a wetting agent in sequence, stir evenly for 10 minutes, and obtain a water-based varnish;

[0090] S31. Add the water-based color paste to the water-based varnish (mass ratio 1.4:1), stir for 25 minutes, and filter with a 200-300 mesh filter to obtain a water-based anti-corrosion coating.

[0091] Example 2

[0092] This example prepares a water-based anti-corrosion coating, the components and contents are shown in Table 2:

[0093] Table 2 Components and contents of water-based anticorrosive coating in Example 2

[0094]

[0095]

[0096] The preparation steps of water-based anti-corrosion coating are as follows:

[0097] S11, preparing water-based color paste: mixing water, water-based resin, neutralizer, dispersant and anti-flash rust agent with high-speed stirring, adding thixotropic agent, pigment and filler according to the particle size from small to large, adding defoamer, dispersing evenly, transferring to a sand mill, grinding until the slurry fineness is ≤25 μm, and adjusting the pH value of the color paste to 8.5-9.5, to obtain a water-based color paste;

[0098] S21. Under stirring conditions, add the water-based resin and the neutralizing agent to a stirring tank in sequence, then slowly add deionized water, stir evenly for 25 minutes, until it is stirred into a homogeneous liquid state, then add a drying agent, a defoaming agent, a thickening thixotropic agent and a wetting agent in sequence, stir evenly for 10 minutes, and obtain a water-based varnish;

[0099] S31. Add the water-based color paste to the water-based varnish (mass ratio 1.33:1), stir for 25 minutes, filter with a 200-300 mesh filter to obtain a water-based anti-corrosion coating.

[0100] Example 3

[0101] This example prepares a water-based anti-corrosion coating, the components and contents are shown in Table 3:

[0102] Table 3 Components and contents of water-based anticorrosive coating in Example 3

[0103]

[0104]

[0105] The preparation steps of water-based anti-corrosion coating are as follows:

[0106] S11, preparing water-based color paste: mixing water, water-based resin, neutralizer, dispersant and anti-flash rust agent with high-speed stirring, adding thixotropic agent, pigment and filler according to the particle size from small to large, adding defoamer, dispersing evenly, transferring to a sand mill, grinding until the slurry fineness is ≤25 μm, and adjusting the pH value of the color paste to 8.5-9.5, to obtain a water-based color paste;

[0107] S21. Under stirring conditions, add the water-based resin and the neutralizing agent to a stirring tank in sequence, then slowly add deionized water, stir evenly for 25 minutes, until it is stirred into a homogeneous liquid state, then add a drying agent, a defoaming agent, a thickening thixotropic agent and a wetting agent in sequence, stir evenly for 10 minutes, and obtain a water-based varnish;

[0108] S31. Add the water-based color paste to the water-based varnish (mass ratio 1.55:1), stir for 25 minutes, and filter with a 200-300 mesh filter to obtain a water-based anti-corrosion coating.

[0109] Comparative Example 1

[0110] This comparative example prepares a water-based anti-corrosion coating, the components and contents are shown in Table 4:

[0111] Table 4 Comparative Example 1 Water-based anti-corrosion coating components and contents

[0112]

[0113]

[0114] The preparation steps of water-based anti-corrosion coating are as follows:

[0115] S11, preparing water-based color paste: mixing water, water-soluble resin, neutralizing agent, dispersant and anti-flash rust agent at high speed, adding thixotropic agent, pigment and filler according to the particle size from small to large, adding defoaming agent, dispersing evenly, transferring to a sand mill, grinding until the slurry fineness is ≤25 μm, and adjusting the pH value of the color paste to 8.5-9.5, to obtain a water-based color paste;

[0116] S21. Under stirring conditions, add the water-soluble resin and the neutralizing agent to a stirring tank in sequence, then slowly add deionized water and a cosolvent, stir evenly for 25 minutes, until it is stirred into a homogeneous liquid state, then add a drying agent, a defoaming agent, a thickening thixotropic agent and a wetting agent in sequence, stir evenly for 10 minutes, and obtain a water-based varnish;

[0117] S31. Add the water-based color paste to the water-based varnish (mass ratio 2.4:1), stir for 25 minutes, and filter with a 200-300 mesh filter to obtain a water-based anti-corrosion coating.

[0118] Comparative Example 2

[0119] This comparative example prepares a water-based anti-corrosion coating, the components and contents are shown in Table 5:

[0120] Table 5 Comparative Example 2 Water-based anti-corrosion coating components and contents

[0121]

[0122]

[0123] The preparation steps of water-based anti-corrosion coating are as follows:

[0124] S11, preparing water-based color paste: mixing water, water-soluble resin, neutralizing agent, dispersant and anti-flash rust agent at high speed, adding thixotropic agent, pigment and filler according to the particle size from small to large, adding defoaming agent, dispersing evenly, transferring to a sand mill, grinding until the slurry fineness is ≤25 μm, and adjusting the pH value of the color paste to 8.5-9.5, to obtain a water-based color paste;

[0125] S21. Under stirring conditions, add the water-soluble resin and the neutralizing agent to the stirring tank in sequence, then slowly add deionized water and the cosolvent, stir evenly for 25 minutes, until it is stirred into a homogeneous liquid state, then add the drying agent, defoaming agent, thickening thixotropic agent and wetting agent in sequence, stir evenly for 10 minutes, and finally add the water-based acrylic emulsion, stir evenly for 5 minutes to obtain a water-based varnish;

[0126] S31. Add the water-based color paste to the water-based varnish (mass ratio 1.55:1), stir for 25 minutes, and filter with a 200-300 mesh filter to obtain a water-based anti-corrosion coating.

[0127] Application Example 1

[0128] S1. Dilute the water-based anti-corrosion coatings in Examples 1-3 and Comparative Examples 1 and 2 with deionized water at a ratio of 1:0.2;

[0129] S2. Use a plunger pump high-pressure airless robot automated spraying to spray the paint on the A3 carbon steel plate whose surface has been degreased and polished;

[0130] The coatings sprayed in S3 and S2 were heated and dried at 60° C. for 30 min to form coatings 1-5.

[0131] Performance Testing

[0132] 1. Refer to GB / T 9751-1988 "Determination of Viscosity of Coatings at High Shear Rates" to test the rotational viscosity of the diluted water-based anti-corrosion coating in step S1 of application example 1. The test results are shown in Table 6;

[0133] 2. Observe and record the construction performance of the water-based anti-corrosion coating in step S2 of application example 1. The results are shown in Table 6.

[0134] 3. After coatings 1-5 in step S3 of Application Example 1 were cured at 15-25°C for 7 days, the coating film appearance was observed, and the corrosion resistance, storage stability, VOC content, adhesion, etc. of the coating were tested. The reference standards for the test indicators and methods are shown in Table 7, and the test results are shown in Table 8.

[0135] Table 6 Viscosity and construction performance test results of water-based anti-corrosion coatings in Application Example 1

[0136]

[0137]

[0138] Note: The sagging film thickness is the maximum wet film thickness that will not show a flow tendency during the drying process when the sample is placed at an angle.

[0139] Table 6 shows the viscosity and construction performance test results of the water-based anti-corrosion coating in Application Example 1. It can be seen from Table 6 that the water-based single-component bottom-to-top integrated quick-drying anti-corrosion coating in Examples 1-3 uses a water-based dispersion resin, and the coating has good construction controllability. The high shear viscosity at 25°C is between 1100 and 1400 mPa·s, which can meet the process requirements of normal spraying construction of a plunger pump high-pressure airless robot automated spraying system, and the TI value of the coating system is greater than 3.2, ensuring that the wet film can reach a sagging film thickness of 250-300 μm in one coating.

[0140] In Comparative Example 1, a water-soluble resin is used to prepare the coating. The high shear viscosity of the water-based one-component anti-corrosion coating at 25°C exceeds 2100 mPa·s, and the viscosity is relatively high, which causes the high-pressure plunger pump for feeding to work laboriously, the paint supply is not smooth, the atomization effect of the robot spraying process is poor, and the sprayed film thickness is uneven. At the same time, the TI value of the coating system is only 1.63, and sagging occurs when the wet film thickness of a single coating reaches 200 μm, indicating that the water-based one-component anti-corrosion coating prepared by the air-drying water-soluble resin has inferior construction controllability to that of the water-based dispersion-type resin.

[0141] In Comparative Example 2, a water-soluble resin is used to prepare the coating. The high shear viscosity of the water-based one-component anti-corrosion coating at 25°C is 1499mPa·s, and it is also suitable for a plunger pump high-pressure airless robot automated spraying system. However, the TI of the coating system is 2.52, and slight sagging begins to occur when the wet film thickness of one coating reaches 200μm; when the dry film thickness of Comparative Example 2 exceeds 80μm, the corresponding wet film thickness exceeds 275μm and begins to have sagging problems.

[0142] Table 7 Test indicators and methods for water-based anti-corrosion coatings and paint film performance in Application Example 1

[0143]

[0144]

[0145] Table 8 Test results of water-based anti-corrosion coating and paint film performance in Application Example 1

[0146]

[0147]

[0148] Table 8 shows the test results of the water-based anticorrosion coating and paint film performance in Application Example 1. It can be seen from Table 8 that the water-based anticorrosion coating prepared in Examples 1-3 has better storage stability than Comparative Examples 1 and 2. Under the drying conditions of 60°C×30min, the initial drying properties of Examples 1-3 and the initial water resistance after curing for 2h are better than those of Comparative Example 1; at the same time, the weather resistance of the water-based anticorrosion coating in Examples 1-3 is significantly better than that of Comparative Example 1, and slightly better than that of Comparative Example 2. In addition to the highest gloss of the paint film in Comparative Example 1, the water-based anticorrosion coating in Examples 1-3 is comparable to that of Comparative Examples 1 and 2 in terms of mechanical properties, water resistance, and neutral salt spray resistance, etc. This shows that the water-based coating provided by the present invention can meet the requirements of the protective performance of the chassis coating of agricultural transportation machinery, and can replace the existing water-based single-component anticorrosion coating. Furthermore, the VOC content of the water-based coatings in Examples 1-3 is lower than 150 g / L, which is significantly lower than 300.96 g / L of Comparative Example 1 and 224.67 g / L of Comparative Example 2, meeting the technical requirements for limiting the VOC content of agricultural machinery coatings in the national standard GB 30981-2020 "Limits of Hazardous Substances in Industrial Protective Coatings", and is more environmentally friendly and safer when used for surface coating of agricultural machinery.

[0149] Figure 1 Schematic diagram of the reaction mechanism of the film-forming process of the water-based anti-corrosion coating in the embodiment of the present invention. The water-based anti-corrosion coating provided by the present invention belongs to a 1K air-drying water-based coating. The coating film-forming process is an air-drying reaction of the ester bonds in the resin with the oxygen of the air to undergo oxygen absorption open-chain crosslinking with the help of Co-based driers, Mn-based driers, Ga-based driers, Fe-based driers and Zr-based driers. The oxygen absorption dry curing process is a free radical reaction, which can be divided into three stages: induction period, initiation period and crosslinking period. No other key components need to be added before the coating is applied. It only needs to be diluted to the construction viscosity with deionized water as a diluent before direct application.

[0150] Figure 2 This is a schematic diagram of the reaction mechanism of the resin component A and the amine curing agent component B of 2K waterborne epoxy coating. Figure 3 The schematic diagram of the reaction mechanism of the component A resin and the component B isocyanate curing agent of the 2K waterborne epoxy coating is that the 2K waterborne epoxy coating is the component A with the resin as the main body and the component B with the curing agent as the main body. Before construction, the components A and B must be mixed evenly according to the strict ratio requirements, and then diluted to the construction viscosity with deionized water as a diluent. That is, the film-forming process of this type of coating is that the cross-linked groups of the component A, such as hydroxyl or epoxy groups, cross-link with the cross-linking groups of the curing agent, such as isocyanate or polyamines, and there will be an applicable period (generally 3-4 hours) after the components A and B are mixed. After the applicable period, the coating is scrapped and cannot be used. The water-based anti-corrosion coating provided by this application has no applicable period, and only needs to be sealed and stored, and can be reopened and used at any time within the shelf life, which is more conducive to resource conservation.

Claims

1. A water-based anti-corrosion coating, characterized in that: The composition comprises the following components in parts by weight: Water-based color paste: Water-based varnish:

2. The water-based anti-corrosion coating according to claim 1, characterized in that: The mass ratio of the water-based color paste to the water-based varnish is (1-3):

1.

3. The water-based anti-corrosion coating according to claim 1, characterized in that: In the water-based color paste or the water-based varnish, the parameters of the water-based resin include at least one of the following: 1) pH 7-10; 2) Solid content is 35-50%; 3) The solvent content is 5-10%; 4) ICI cone and plate viscometer, viscosity 1000-5000 mPa·s at 25°C; 5) Acid value ≤35mgKOH / g.

4. The water-based anti-corrosion coating according to claim 3, characterized in that: In the water-based color paste or the water-based varnish, the water-based resin is an air-drying water-based dispersion resin; Preferably, the air-drying water-based dispersion resin includes at least one of a water-based modified epoxy ester dispersion and a water-based modified alkyd dispersion.

5. The water-based anti-corrosion coating according to claim 1, characterized in that: The drying agent includes at least one of a Co-based drying agent, a Mn-based drying agent, a Ga-based drying agent, a Fe-based drying agent and a Zr-based drying agent.

6. The water-based anti-corrosion coating according to any one of claims 1 to 5, characterized in that: The water-based color paste further comprises, by weight, 0-2.5 parts of a dispersant, 0-30 parts of a filler, and 0-0.5 parts of a defoamer; And / or, the water-based varnish further comprises 0-0.5 parts of a defoamer, 0-1 parts of a thickener, and 0-0.5 parts of a wetting agent.

7. The method for preparing the water-based anticorrosive coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mixing the components of the water-based color paste to obtain the water-based color paste; Mixing the components of the water-based varnish to obtain the water-based varnish; The water-based color paste and water-based varnish are mixed to obtain the water-based anti-corrosion coating.

8. A coating, characterized in that The invention is formed by the water-based anti-corrosion coating according to any one of claims 1 to 6.

9. The coating according to claim 8, characterized in that The conditions for forming the coating include at least one of the following: 1) The water-based anti-corrosion coating is diluted with deionized water before use; 2) The water-based anti-corrosion coating is sprayed by a plunger pump high-pressure airless robot automated spraying system; 3) The curing temperature of the water-based anti-corrosion coating is 50-80°C; the curing time is 20-40min.

10. Use of the water-based anti-corrosion coating according to any one of claims 1 to 6 in surface coating of agricultural transport machinery.

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