CN118772765A - A kind of water-based solid color base paint and its preparation method and application - Google Patents

Abstract

The present invention relates to the technical field of automotive coatings, and specifically discloses a water-based solid color base paint and a preparation method and application thereof. The water-based solid color base paint is composed of a component A and a component B in a mass ratio of 100:(0-10), and a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a high glass transition temperature and a water-based aliphatic anionic polyurethane dispersion with a low glass transition temperature are compounded as film-forming resins, and a water-based self-crosslinking low-hydroxyl acrylate dispersion is selectively added. Through the synergistic effect and specific proportion of each raw material component, the characteristics of different types of water-based resins are brought into the best state, so that the water-based solid color base paint has excellent anti-sagging, color bridging ability and interlayer adhesion, no fly ash, and excellent mechanical properties and corrosion resistance. It can be constructed on a large area under high temperature, low temperature or high humidity environment, and has good coordination with the "wet spray wet" coating of the topcoat varnish, and has high practical value and promotion value.

Description

A kind of water-based solid color base paint and its preparation method and application

Technical Field

The invention relates to the technical field of vehicle coatings, and in particular to a water-based solid color base paint and a preparation method and application thereof.

Background Art

Rail transit vehicles are a major means of transportation for the public. Most rail transit vehicles are manufactured using lightweight aluminum alloys instead of steel. With the change in the material of the carriage, the types and quality of coatings have also changed. Rail transit vehicles operate in various environments from C2 to C5, which determines that their coatings must take into account both anti-corrosion and decorative effects. The coating system of water-based basecoat + clearcoat has the advantages of low VOC content, fast drying, high hardness, impact resistance, strong adhesion, good appearance, excellent anti-corrosion performance, green environmental protection, safe and convenient construction, and energy saving. It has become the mainstream direction of the development of the modern coatings industry. Basecoat is a coating used between the middle coating and the clearcoat, which mainly plays a role in coloring, covering and decoration. The basecoat uses organic and inorganic pigments to delay the aging damage of ultraviolet light to the coating; the basecoat layer has good shielding properties, preventing the penetration of water, gas and ions, thereby protecting the paint film and having a good decorative effect.

When the "water-based solid color base paint + clear coat" system for rail transit vehicles is applied, the solid color base paint and clear coat are applied "wet on wet". During the conversion process of the water-based matching coating, due to the large construction area of the rail transit vehicle body painting, when the construction environment temperature is too high, too low or the humidity is high, it is easy to have problems such as sagging, fly ash, difficulty in connecting the gun or poor interlayer adhesion. Therefore, the existing water-based base paint must be applied under constant temperature and humidity conditions. In order to solve the problem of harsh base paint construction conditions, it is urgent to find a water-based solid color base paint that can be applied in high temperature, low temperature or high humidity environments, and at the same time, the paint film joint has a smooth transition, the surface is flat and smooth, and the "wet-spray-wet" adhesion between the intermediate coating and the base paint, and the base paint and the clear coat is excellent, so as to meet the actual needs of the application of water-based solid color base paint in rail transit vehicle painting.

Summary of the invention

In response to the above problems, the present invention provides a water-based solid color base paint and a preparation method and application thereof. Through the synergistic effect of various raw material components, it can be constructed on a large area under high temperature, low temperature or high humidity environments, cooperates well with the "wet spray wet" coating of topcoat varnish, and has excellent comprehensive performance.

In order to solve the above technical problems, the technical solution provided by the present invention is:

In a first aspect, the present invention provides a water-based solid color base paint, which is composed of component A and component B in a mass ratio of 100: (0-10); wherein,

The A component comprises the following raw material components in mass percentage: 10% to 25% of an aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 10% to 20% of an aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 0% to 10% of an aqueous self-crosslinking low-hydroxy acrylate dispersion, 1% to 3% of a neutralizer, 2% to 4% of an aqueous cellulose acetate butyrate solution, 3% to 6% of a first cosolvent, 0.2% to 1% of a first surfactant, 0.2% to 1% of a substrate wetting agent, 0.1% to 1% of a leveling agent, 12% to 45% of an aqueous color paste, 0.2% to 1% of a first defoamer, 0.3% to 1.5% of a thickener, and 10% to 30% of water; the aqueous color paste comprises water, a dispersant, a second defoamer, a second surfactant, a pigment, a color paste stabilizer, and a neutralizer;

The B component includes the following raw material components in percentage by mass: 70% to 80% of a curing agent and 20% to 30% of a second co-solvent; the curing agent is at least one of hexamethylene diisocyanate or a hydrophilic aliphatic polyisocyanate.

Compared with the prior art, the water-based solid color base paint provided by the present invention comprises component A as the main paint component and component B as the curing component; component A is a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a high glass transition temperature and a water-based aliphatic anionic polyurethane dispersion with a low glass transition temperature for compounding as film-forming resins, and selectively adds a water-based self-crosslinking low-hydroxyl acrylate dispersion, and through a specific ratio and the synergistic effect of each component, the characteristics of different types of water-based resins are brought into play to the best state, so that the final water-based solid color base paint has a higher solid content, better gloss and thixotropy, and good overlap when spraying over a large area (the overlapped part during multi-pass spraying), and the thixotropy is improved to above 4.8 degrees, while the flexibility and hardness of the cured film are balanced (can be improved to above 2H), which can effectively solve the problem of difficult "wet spray wet" matching coating construction in the "water-based solid color base paint + topcoat clear varnish" system.

The paint film prepared by waterborne polyurethane dispersion is soft, has good thixotropic index and anti-sagging properties, and has a moderate drying speed. At the same time, it has good permeability, and different spraying techniques have little effect on the color effect of the base paint, with high coating efficiency, and strong bonding with the upper and lower layers. When matched with the clearcoat, it is in a good state of "neither dry nor wet", which can ensure good interlayer adhesion and is not easily "re-dissolved" by the clearcoat (when matched with the clearcoat wet spray, the cosolvent in the clearcoat will redissolve the base paint). The flexibility of the molecular chain is the most important factor in determining the glass transition temperature (Tg, referred to as the glass transition temperature) of the polymer. The better the flexibility of the main chain, the lower the glass transition temperature. The present invention finds through a large number of tests that an aqueous polyurethane dispersion with a low glass transition temperature can still maintain good flexibility in a low temperature environment and can improve the film-forming property under low temperature conditions; an aqueous polyurethane dispersion with a high glass transition temperature can improve the adaptability of the coating in a high temperature environment and enhance its high temperature resistance; and compounding aqueous polyurethane dispersions with different glass transition temperatures can adapt to and improve the paint film construction property under various complex conditions such as high temperature and low temperature, and can form a smooth and bright coating.

In addition, the water-based self-crosslinking low-hydroxyl acrylate dispersion has a lower hydroxyl content in the molecule, more chemical bonds between molecules, and a more orderly arrangement between molecules, so it has a higher viscosity, better thixotropic index and anti-sagging properties; the lower the hydroxyl value, the worse the hydrophilicity, and the stronger the water resistance after film formation. However, due to the shortcomings of fast drying, poor interlayer adhesion and poor water resistance, water-based self-crosslinking low-hydroxyl acrylate dispersions and water-based acrylic resin emulsions are difficult to apply with a gun; and they are easily dissolved or corroded by organic solvents, acids, alkalis and other chemical substances, and the paint film shrinks quickly, with many pits and obvious particles; at the same time, the water-based solid color base paint prepared by water-based self-crosslinking low-hydroxyl acrylate dispersions has blue or white light on the sides, which is difficult to adjust the color and cannot meet the requirements of large-area spraying of rail transit vehicle bodies and rapid color adjustment of later repair paints. By compounding a certain proportion of water-based self-crosslinking low-hydroxyl acrylate dispersion into a hydroxyl-free water-based polyurethane dispersion, chemical crosslinking can occur between hydroxyl (-OH) and isocyanate (-NCO) curing agent to further enhance the adhesion of the paint film; the synergistic effect of water-based polyurethane dispersion and water-based self-crosslinking low-hydroxyl acrylate dispersion can make up for the respective deficiencies of water-based polyurethane dispersion and water-based acrylic resin emulsion (single water-based polyurethane dispersion has poor self-thickening property, low solid content, and poor water resistance, heat resistance and gloss of the paint film; single water-based acrylic resin emulsion is hot-sticky and cold-brittle, has poor flexibility, is not solvent-resistant, and is difficult to color).

The present invention obtains a water-based solid color base paint with excellent comprehensive performance through the synergistic effect of each raw material component and a specific ratio content. The results of the embodiments show that the water-based solid color base paint provided by the present invention can be applied on a large area under high temperature, low temperature or high humidity environment, and cooperates well with the "wet spray wet" coating of the topcoat varnish. Under the premise of not affecting the construction fluidity, it has excellent anti-sagging, color joint ability and interlayer adhesion, no fly ash, and at the same time has excellent mechanical properties and corrosion resistance, and has high practical value and promotion value.

Preferably, the solid contents of the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C., the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature ≤ 5° C., and the aqueous self-crosslinking low-hydroxy acrylate dispersion are all 34% to 41%.

Preferably, the hydroxyl content of the aqueous self-crosslinking low-hydroxyl acrylate dispersion is 1% to 2%.

Preferably, the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion having a glass transition temperature of 40 to 50° C. is Bayhydol UH 2606 produced by Covestro.

Preferably, the aqueous self-crosslinking low-hydroxyl acrylate dispersion is Bayhydrol A 2846 produced by Covestro.

Preferably, the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5° C. is at least one of Bayhydrol UH 2648/1, Bayhydrol UH 2110, Bayhydrol UH 2621 or Bayhydrol UH 2952/1.

In the present invention, the aliphatic anionic polyurethane dispersion has the advantages of light color, high transparency, good compatibility, slightly slow drying speed, soft paint film, moderate film volume shrinkage, strong corrosion resistance and strong interlayer adhesion, etc. It can minimize the interference with the color of the paint wet film state, has the rapid color adjustment required by the repair paint, has excellent leveling, chemical resistance and weather resistance after film formation, and has high toughness and good elasticity. Among them, low glass transition temperature water-based aliphatic anionic polyurethane dispersions (especially Covestro Bayhydrol UH 2952/1) and high glass transition temperature water-based polycarbonate-containing aliphatic anionic polyurethane dispersions (Covestro Bayhydol UH 2606) can be attached to the body surface (or OEM product surface) without polishing, and have excellent adhesion and chemical resistance. They can not only meet the needs of large-area spraying of rail transit vehicle bodies, but also work well with the "wet spray wet" coating of clearcoat varnishes. They are particularly suitable for repairing paint under infrared baking lamps, or after pre-baking, they can be coated with two-component polyurethane varnish on the solid color base paint coating. Low hydroxyl value resins (water-based self-crosslinking low hydroxyl acrylate dispersions) have a higher viscosity due to the low hydroxyl content in the molecules, more chemical bonds between molecules, and more orderly arrangement between molecules; in addition, the lower the hydroxyl value, the worse the hydrophilicity, and the stronger the water resistance after film formation. Adding a certain amount of low hydroxyl value resin to the film-forming resin can improve the thixotropic index and anti-sagging properties of the coating.

Preferably, the pigment is an organic pigment or an inorganic pigment.

Preferably, the A component includes 15% to 40% of the water-based color paste. Further preferably, the A component includes 20% to 37% of the water-based color paste. More preferably, when the pigment is an organic pigment, the A component includes 21% to 26% of the water-based color paste; when the pigment is an inorganic pigment, the A component includes 32% to 37% of the water-based color paste.

Preferably, based on 100% of component A, the aqueous color paste includes 5% to 14% water, 0.8% to 1.4% dispersant, 0.2% to 0.5% second defoamer, 0.2% to 1% second surfactant, 5% to 13% organic pigment, 0.9% to 4.5% color paste stabilizer and 0.1% to 0.3% neutralizer.

Preferably, based on 100% of component A, the aqueous color paste includes 5% to 12% water, 1.2% to 1.8% dispersant, 0.2% to 0.5% second defoamer, 0.2% to 0.5% second surfactant, 15% to 25% inorganic pigment, 1.5% to 7% color paste stabilizer and 0.1% to 0.3% neutralizer.

Preferably, the dispersant is at least one of a nonionic wetting dispersant or an anionic wetting dispersant.

Further preferably, the nonionic wetting and dispersing agent is at least one of BYK DISPERBYK-190, BYK DISPERBYK-LPN 23160, BYK DISPERBYK-2010, BYK DISPERBYK-2012, allnex VXW6208-60 or BASF DispexUltra PX 4585.

Further preferably, the anionic wetting and dispersing agent is at least one of TEGO Dispers 747W, TEGO Dispers 757W, TEGO Dispers 750W or TEGO Dispers 755W.

Further preferably, the dispersant comprises a nonionic wetting dispersant and an anionic wetting dispersant in a mass ratio of 1:1 to 2.5:1.

Preferably, the mass ratio of the non-volatile matter of the dispersant to the organic pigment is 0.02:1 to 0.2:1.

Preferably, the mass ratio of the non-volatile matter of the dispersant to the inorganic pigment is 0.03:1 to 0.05:1.

Preferably, the second defoaming agent is at least one of BYK-011, BYK-024, BYK-1711 or TEGO-810.

Preferably, the second surfactant is at least one of an acetylenic glycol surfactant or an alcohol alkoxy compound.

More preferably, the second surfactant is at least one of Surfynol AD01, Surfynol 440, Surfynol 104BC or BYK-DYNWET 800.

In the present invention, Surfynol AD01 is a Gemini acetylene glycol surfactant, HLB value (hydrophile-lipophile balance) = 4, has defoaming and wetting functions, can provide defoaming, dynamic wetting and help film-forming effects; Surfynol 440 is a nonionic acetylene glycol ethoxy compound, has low dynamic tension, good compatibility, HLB value = 8, has Gemini wetting and low foaming effects, can reduce the dynamic and static surface tension of the system, and prevent the occurrence of shrinkage holes, pinholes and fish eyes; Surfynol 104BC is a Gemini tetramethyldecynediol nonionic surfactant, has wetting, leveling, defoaming and other functions; BYK-DYNWET 800 is an alcohol alkoxy compound, has a slight foam stabilizing function, can reduce the dynamic surface tension of the system, and is particularly suitable for high-speed construction grinding slurry.

Preferably, the organic pigment is at least one of bright chestnut red, phthalocyanine green, phthalocyanine blue, organic yellow or carbon black.

Preferably, the inorganic pigment is titanium dioxide.

Preferably, the color paste stabilizer includes at least three of water-based fumed silica, modified urea rheological additive, resin-free color paste moisturizer or anti-drying agent for water-based pigment concentrate.

Further preferably, the color paste stabilizer includes at least three of Degussa AEROSIL R972, BYK RHEOBYK-420, TEGO Humectant 7005 or BYKETOL-PC.

More preferably, the color paste stabilizer includes Degussa AEROSIL R972, BYK RHEOBYK-420 and TEGO Humectant 7005 in a mass ratio of 1:1:8 to 1:1:12.

More preferably, the color paste stabilizer includes Degussa AEROSIL R972, BYK RHEOBYK-420 and BYKETOL-PC in a mass ratio of 1:1:8 to 1:1:12.

In the present invention, AEROSILR972 is a water-based fumed silica, which contains silanol groups on its surface. After being fully stirred and dispersed, hydrogen bonds are formed between the silanol groups to produce a three-dimensional network structure, thereby increasing the viscosity of the dispersion system, producing thixotropic flow properties, and playing an anti-settling role, thereby improving the stability, corrosion resistance and thixotropy of the pigment; RHEOBYK-420 is a modified urea rheological additive, which has anti-settling and anti-sagging effects and can produce a thixotropic effect; TEGO Humectant 7005 is a resin-free color paste moisturizer; BYKETOL-PC is an anti-drying agent for water-based pigment concentrates, which is also a modified urea solution. Based on a specific molecular structure, water evaporation can be optimally controlled to ensure that the water-based pigment concentrate does not dry out too quickly.

Preferably, the neutralizing agent is an 8 wt % to 12 wt % aqueous solution of dimethylethanolamine.

Preferably, the method for preparing the water-based color paste comprises the following steps:

Add the dispersant, the second defoamer and the second surfactant into water, mix them evenly, add the pigment and the color paste stabilizer, grind them, add the neutralizer, and obtain the water-based color paste.

For example, the preparation method of the water-based color paste comprises the following steps:

Add water to a clean container, stir at 280rpm-320rpm, add dispersant and second defoamer in sequence, adjust the speed to 800rpm-1500rpm, add second surfactant, stir for 5min-10min to make it uniform; adjust the speed to 1500rpm-2000rpm, add pigment and color paste stabilizer in sequence, adjust the speed to 2000rpm-3000rpm, disperse and stir for 25min-40min; grind with horizontal grinder or basket grinder; finally add neutralizer, mix well to obtain water-based color paste.

Since the second surfactant has low solubility in water (such as Surfynol AD01's HLB=4, solubility in water is 0.1%), low molecular weight, and is volatile, in order to fully adsorb it onto various particles in the system to achieve good compatibility, it needs to be fully dispersed. It is recommended that the dispersion speed be no less than 800rpm to avoid water sensitivity problems.

More preferably, the pH of the aqueous color paste is 8 to 8.5.

More preferably, the fineness of the water-based color paste is 10 μm to 20 μm.

It should be noted that there is no need to adjust the pH before and during grinding, and no other components such as resins, amines, organic co-solvents, thickeners, etc. are added, otherwise the grinding effect of the pigment slurry will be affected.

Preferably, the aqueous cellulose acetate butyrate solution comprises the following raw material components in percentage by mass: 15% to 25% aqueous cellulose acetate butyrate, 0% to 0.5% neutralizer and 74.5% to 85% medium solution, and the sum of the components is 100%.

More preferably, the aqueous cellulose acetate butyrate is Eastman Solus 3050.

Further preferably, the medium solution is at least one of an aqueous solution of ethylene glycol butyl ether, an aqueous solution of propylene glycol methyl ether, an aqueous solution of dipropylene glycol dimethyl ether, an aqueous solution of N-methylpyrrolidone, an aqueous solution of dimethyl sulfoxide, an aqueous solution of dimethylformamide, an aqueous solution of N-methylformamide or an aqueous solution of tetrahydrofuran.

More preferably, the mass concentration of the medium solution is 50% to 75%.

More preferably, the medium solution is a 50% to 75% aqueous solution of ethylene glycol butyl ether.

More preferably, the medium solution consists of a first medium, a second medium and water in a mass ratio of 2:1:3 to 2:2:3; the first medium is ethylene glycol butyl ether (BCS) or dipropylene glycol dimethyl ether (DMM), and the second medium is N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF) or tetrahydrofuran (THF).

In the present invention, the specific medium has excellent stability, fluidity and solubility, can significantly reduce the surface tension of the system, play the role of auxiliary leveling agent, and improve the spreadability and adhesion of the coating; by compounding the first co-solvent, it can play the role of stabilizing the liquid mixture.

Preferably, the method for preparing the aqueous cellulose acetate butyrate solution comprises the following steps:

The aqueous cellulose acetate butyrate is added to the medium solution, mixed evenly, and the pH value of the mixed solution is adjusted to 8-8.5 with a neutralizer to obtain an aqueous cellulose acetate butyrate solution.

For example, the method for preparing the aqueous cellulose acetate butyrate solution comprises the following steps:

Add aqueous cellulose acetate butyrate into the medium solution, disperse at 1000 rpm to 1500 rpm for 10 to 20 minutes, and adjust the pH value of the mixed solution to 8 to 8.5 with a neutralizer to obtain an aqueous cellulose acetate butyrate solution.

Preferably, the first cosolvent includes at least three of dipropylene glycol dimethyl ether, propylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol methyl ether, dimethyl sulfoxide, N-methylpyrrolidone, diethylene glycol monobutyl ether or dipropylene glycol butyl ether.

Further preferably, based on the A component as 100%, the first co-solvent includes 1% to 2% of a first solvent, 0.75% to 1.5% of a second solvent and 1.25% to 2.5% of a third solvent; the first solvent includes at least one of dipropylene glycol dimethyl ether (DMM) or propylene glycol butyl ether (PNB), the second solvent includes at least one of ethylene glycol butyl ether (BCS), dipropylene glycol methyl ether (DPM) or dimethyl sulfoxide (DMSO), and the third solvent includes at least one of N-methylpyrrolidone (NMP), diethylene glycol monobutyl ether (BDG) or dipropylene glycol butyl ether (DPNB).

More preferably, the first co-solvent comprises propylene glycol butyl ether (PNB), dipropylene glycol dimethyl ether (DMM), ethylene glycol butyl ether (BCS), dipropylene glycol methyl ether (DPM), N-methylpyrrolidone (NMP) and dipropylene glycol butyl ether (DPNB) in a mass ratio of 1.5:0.5:0.5:1:1.5:1.

The present invention is conducive to balancing the volatilization rate and improving the solubility in water during the film-forming process by controlling the boiling point (gradient boiling point) of the first cosolvent and the solubility of the solvent miscible with water (including the solubility of the solvent in water and the solubility of water in the solvent). The specific first cosolvent can couple different phases and interact with the solution system in the water-based coating to produce a tiny phase separation, which helps to reduce the surface tension of the water-based system and enhance the fluidity of the coating, thereby adjusting its coating properties, increasing the viscosity of the water-based coating, changing the drying time of the coating, improving the wettability and coating effect of the coating, and improving the water resistance and solvent resistance of the paint film. The preferred first cosolvent can also be used as a film-forming aid, and its unique hydrophilic and lipophilic balance characteristics enable it to exert different film-forming effects on different resins, helping the coating to form a uniform and smooth coating, and in particular, it can significantly reduce the surface tension of the system and has an auxiliary leveling effect.

Preferably, the first surfactant is a gemini acetylenic diol surfactant.

Further preferably, the first surfactant is at least one of Surfynol 440 from Air Chemistry or Surfynol 104BC from Air Chemistry.

Preferably, the substrate wetting agent is a polyether-modified silicone surfactant.

Further preferably, the substrate wetting agent is at least one of BYK-345, BYK-346, BYK-347, Tego-4100, Tego-280 or Surfynol 104BC.

The preferred substrate wetting agent of the present invention can effectively reduce the surface tension of the system, significantly improve the substrate wettability of the system, and does not increase the surface slipperiness, and is suitable for all aqueous systems without cosolvents.

Preferably, the leveling agent is at least one of BYK-378, BYK-381, BYK-333, BYK-331, Tego-4100 or Surfynol 104BC.

The paint molecules are constantly moving during the leveling process. As the viscosity of the paint gradually increases during the leveling process, the system molecules gradually form Bénard vortices, which leads to defects such as pinholes and sagging in the film-forming process. Among the preferred leveling agents of the present invention, BYK-378 is a polyether-modified dimethyl polysiloxane, which can significantly reduce the surface tension of the system, improve the surface smoothness, and thus improve the anti-scratch performance of the paint. It also has excellent substrate wettability and good anti-shrinkage effect, and has a good effect even at a low addition amount. It also has low foam stability, good compatibility, and is easy to recoat without causing oil spots; BYK-381 is an ionic polyacrylate solution type surface additive, which can improve the leveling and substrate wettability of water-based basecoat and overprint varnish, and prevent surface defects (shrinkage and pinholes); Tego-4100 is a leveling agent with a twin structure, which has high activity and unstable foam. Even at extremely low concentrations, it can effectively reduce surface tension and improve wettability and leveling performance.

The dynamic surface tension of the wet film needs to be slightly lower than the surface tension of the substrate, so that the paint film can wet the substrate well and form a continuous and stable paint film. The preferred first surfactant, substrate wetting agent and leveling agent of the present invention have low water sensitivity, which can effectively reduce the surface tension and achieve a balance between static and dynamic surface tensions. The special structure enables it to have wetting and defoaming effects, which can improve the dispersibility of the system, improve fluidity and leveling, control foam, and stabilize consistency and viscosity.

Preferably, the first defoaming agent is at least one of BYK-093, BYK-011 or TEGO-830.

Preferably, the thickener is a polyurethane associative thickener.

Further preferably, the thickener is at least one of Hemmings RHEOLATE 299, BYK RHEOBYK-H 7625VF or Rohm and Haas RM-8W.

More preferably, the thickener is at least two of Hemmings RHEOLATE 299, BYK RHEOBYK-H 7625VF or Rohm and Haas RM-8W.

In the present invention, RHEOLATE 299 and RHEOBYK-H 7625VF are the same type of polyurethane associative thickeners and are not affected by pH value; RHEOLATE 299 can provide efficient thickening in the medium and low shear rate range, and RHEOBYK-H7625VF can sharply increase the viscosity under low shear, and the two play a complementary role; RM-8W is a low-odor, solvent-free, hydrophobically modified polyurethane nonionic associative thickener with excellent flow and leveling properties, uniform film-forming properties, glossiness and high thickening efficiency.

Preferably, the solid content of component A is 20% to 45%.

More preferably, when the pigment is an organic pigment, the solid content of component A is 20% to 30%.

More preferably, when the pigment is an inorganic pigment, the solid content of component A is 33% to 45%.

In the present invention, the solid content of component A refers to the mass ratio of all solid components in component A (including resin dispersion and pigment).

Preferably, based on 100% of the B component, the curing agent includes 25% to 30% of low-viscosity hydrophobic hexamethylene diisocyanate, 25% to 30% of high-viscosity hydrophilic hexamethylene diisocyanate and 18% to 22% of hydrophilic modified isophorone diisocyanate.

It should be noted that the hydrophilic modified isophorone diisocyanate in the present invention refers to a hydrophilic modified aliphatic polyisocyanate based on isophorone diisocyanate (IPDI).

Further preferably, the low-viscosity hydrophobic hexamethylene diisocyanate is at least one of Covestro Desmodur N3900, Covestro Desmodur N3600 or Wanhua WANNATE HT-600.

Further preferably, the high-viscosity hydrophilic hexamethylene diisocyanate is at least one of Bayhydrol XP2655, Bayhydur XP 2547, Bayhydur XP 2487/1, Bayhydur 304 or Bayhydur 305.

Preferably, the solid content of the hydrophilic aliphatic polyisocyanate is 60% to 70%.

Preferably, the -NCO content of the hydrophilic aliphatic polyisocyanate is 8.5% to 9.5%.

Further preferably, the hydrophilic aliphatic polyisocyanate is at least one of Covestro Bayhydur 401-70 and Covestro Bayhydur 401-60.

The present invention can further enhance the curing effect and improve the construction fluidity, viscosity and glossiness of the coating by limiting the type of curing agent.

Preferably, the second co-solvent is at least one of propylene glycol methyl ether acetate (PMA), propylene glycol methyl ether acrylate (PMP), propylene carbonate (PC), propylene glycol diacetate (PGDA), ethylene glycol butyl ether acetate (BGA), dibasic acid ester (DBE) or dipropylene glycol dimethyl ether (DMM).

In the present invention, a certain amount of the second cosolvent is added to the curing component, which can not only improve the compatibility of the curing agent with the water-based self-crosslinking low-hydroxyl acrylate dispersion, but also prolong the open time of the paint film, which is beneficial to leveling. The specific second co-solvents are all environmentally friendly solvents with the following characteristics: (1) they contain multiple functional groups and have strong solubility for both polar and non-polar substances, which can improve the strength of the coating film; (2) they have low surface tension, strong solvent power, low viscosity and good volatility, which can provide good solubility and fluidity, ensure uniform coating and easy construction, and at the same time improve the adhesion and durability of the coating, adjust the volatilization rate of the entire system, adjust the drying speed of the paint film, reduce pinholes and fish eyes, and increase gloss, wetting, leveling and re-leveling properties; (3) propylene carbonate has good film-forming properties and strong carbon dioxide absorption capacity. When used with a hydrophilic isocyanate curing agent, the effect is excellent and can improve prickly heat and reduce bubbles; (4) The use of multiple second co-solvents can complement each other to achieve a better overall effect. In addition, by compounding second co-solvents with different boiling points (gradient boiling points), it is beneficial to balance the volatilization rate during the film-forming process and improve the solubility in water. For example, the synergy of propylene glycol methyl ether acetate (PMA), propylene glycol methyl ether propionate (PMP) and propylene carbonate (PC) can not only improve the strength of the coating film, but also facilitate the stable storage of the coating. It can also absorb carbon dioxide during the coating and film-forming process, and is extremely effective in diluting water-based isocyanate curing agents.

Preferably, the mass ratio of the component A to the component B is 100:(0-5), and more preferably 100:(0-2).

Preferably, when the component A contains the aqueous self-crosslinking low-hydroxyl acrylate dispersion, the molar ratio of -NCO to -OH is 1.2:1 to 1.5:1.

It should be noted that when component A does not contain the aqueous self-crosslinking low-hydroxyl acrylate dispersion, the curing component may not be added.

In a second aspect, the present invention provides a method for preparing a water-based solid color base paint, comprising the following steps:

S1, weighing various raw materials according to the designed ratio, mixing the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C., the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5° C., and the aqueous self-crosslinking low-hydroxy acrylate dispersion, adding water and a neutralizing agent; then sequentially adding an aqueous cellulose acetate butyrate solution, a first cosolvent, a first surfactant, a substrate wetting agent, a leveling agent, an aqueous color paste, a first defoamer, and a thickener, mixing evenly, and obtaining component A;

S2, adding the curing agent into the second co-solvent, mixing evenly, to obtain component B.

It should be noted that there is no order of precedence for steps S1 and S2.

The preparation method of the water-based solid color base paint provided by the invention does not require special treatment of the raw materials and is simple and easy to implement.

For example, the preparation method of component A comprises the following steps:

Weigh the raw materials according to the designed ratio, add the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40-50°C, the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C and the aqueous self-crosslinking low-hydroxy acrylate dispersion into a clean container, add water at 600rpm-800rpm, and stir for 4min-6min; then add the neutralizer to adjust the pH of the system to 8-8.5; then add the aqueous cellulose acetate butyrate solution, the first cosolvent, the first surfactant, the substrate wetting agent, the leveling agent, the aqueous color paste and the first defoaming agent in sequence, and continue to stir at 600rpm-800rpm for 5min-10min; finally add the thickener, mix well, and obtain component A.

In a third aspect, the present invention provides the use of the above-mentioned water-based solid color base paint in automotive coatings.

Preferably, the vehicle coating is a coating for rail transit vehicles.

In a fourth aspect, the present invention provides a method for using the above-mentioned water-based solid color base paint, comprising the following steps:

Component A and component B are mixed evenly, an activating diluent is added, and mixed evenly to obtain a construction coating with a solid content of 20% to 40%, which is evenly applied to a metal substrate or a mid-coat; the activating diluent includes an aqueous cellulose acetate butyrate solution, a rheological additive, a surface additive and a stabilizer.

It should be noted that if the water-based solid color basecoat does not contain component B, just add the activated diluent to component A and mix well.

Preferably, when the pigment in the component A is an organic pigment, the solid content of the construction coating is 20% to 30%.

Preferably, when the pigment in the component A is an inorganic pigment, the solid content of the construction coating is 25% to 40%.

The inventor has found through a large number of experiments that under the same number of spraying passes, when the solid content of the construction is 20% to 40% (including 20% to 30% for organic pigments and 25% to 40% for inorganic pigments), after application, as the water evaporates rapidly, when the volume of the resin particles accounts for a critical value of the total system volume, the system slowly changes from liquid to solid, and reaching the critical point is the beginning of the surface drying of the water-based paint. With the further evaporation of water and solvent, the macromolecules and organic small molecules in the resin particles interpenetrate each other, the viscosity of the system increases, and the volume of the coating shrinks until it becomes a solid paint film. Generally, the higher the construction solid content, the closer it is to the critical value of the surface drying, and the faster the drying speed. However, too high a solid content of the construction will also bring a series of unfavorable factors, which will increase the difficulty of spraying and performance adjustment of the coating, such as poor leveling, too fast surface drying, shortening the application interval, easy fly ash in large-area construction, rough paint film surface, and difficulty in gunning, etc., and the brightness is reduced after glazing, forming blackening and graying phenomena visible to the naked eye. The solid content of the construction is low, the construction sagging, rheological properties are poor, the hiding power is poor, and the paint film thickness cannot be increased, so that the number of construction spraying passes needs to be increased to achieve a suitable dry film thickness and hiding power. The present invention controls the solid content of the construction coating to 20% to 40% (wherein the organic pigment is 20% to 30%, and the inorganic pigment is 25% to 40%), which can ensure that the comprehensive effects of paint film leveling, dry film thickness, hiding power and construction performance after application reach the best state, and the dry film thickness can be controlled to 20μm to 30μm by spraying 2 to 3 passes, and at the same time ensure that the paint film is smooth and fine, has good hiding power, does not sag during construction, resists orange peel, resists prickly heat, etc.

In the method for using water-based solid color basecoat, a unique activated diluent is used to dilute the water-based solid color basecoat (component A + component B), which has the following beneficial effects: (1) improving the system's tolerance to high content of surfactants or extreme pH values; (2) preventing the paint from sagging or miscibility during "wet-on-wet" construction; (3) during large-area spraying construction, it can accelerate the formation of the structure after construction, thereby improving the adhesion of the vertical surface (improving the interlayer adhesion between the water-based solid color basecoat and the clearcoat), and preventing the clearcoat from being "re-dissolved".

Preferably, the activated diluent comprises the following raw material components in percentage by mass: 28% to 31.5% aqueous cellulose acetate butyrate solution, 48% to 54% rheological additive, 4% to 4.5% surface additive and 10% to 20% stabilizer, the sum of the components being 100%.

Preferably, the mass ratio of the component A to the activated diluent is 100:(10-20).

The present invention adopts the above mass ratio to ensure that the solid content of the construction coating is 20% to 35%.

Preferably, the aqueous cellulose acetate butyrate solution comprises the following raw material components in percentage by mass: 15% to 25% aqueous cellulose acetate butyrate, 0% to 0.5% neutralizer and 74.5% to 85% medium solution, and the sum of the components is 100%.

More preferably, the aqueous cellulose acetate butyrate is Eastman Solus 3050.

Further preferably, the medium solution is at least one of an aqueous solution of ethylene glycol butyl ether, an aqueous solution of propylene glycol methyl ether, an aqueous solution of dipropylene glycol dimethyl ether, an aqueous solution of N-methylpyrrolidone, an aqueous solution of dimethyl sulfoxide, an aqueous solution of dimethylformamide, an aqueous solution of N-methylformamide or an aqueous solution of tetrahydrofuran.

More preferably, the mass concentration of the medium solution is 50% to 75%.

More preferably, the medium solution is a 50% to 75% aqueous solution of ethylene glycol butyl ether.

More preferably, the medium solution consists of a first medium, a second medium and water in a mass ratio of 2:1:3 to 2:2:3; the first medium is ethylene glycol butyl ether (BCS) or dipropylene glycol dimethyl ether (DMM), and the second medium is N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF) or tetrahydrofuran (THF).

Preferably, the method for preparing the aqueous cellulose acetate butyrate solution comprises the following steps:

The aqueous cellulose acetate butyrate is added to the medium solution, mixed evenly, and the pH value of the mixed solution is adjusted to 8-8.5 with a neutralizer to obtain an aqueous cellulose acetate butyrate solution.

Preferably, the rheological additive comprises the following raw material components in percentage by mass: 1.5% to 2.5% of organic modified synthetic layered silicate, 1.5% to 2.5% of emulsifying dispersant and 95% to 97% of water, and the sum of the components is 100%.

More preferably, the organic-modified synthetic layered silicate is BYK Laponite-RD.

Further preferably, the emulsifying dispersant is at least one of polyethylene glycol and polypropylene glycol. If the emulsifying dispersant includes polyethylene glycol and polypropylene glycol, the mass ratio of polyethylene glycol to polypropylene glycol may be 1:1.

More preferably, the emulsifying dispersant is at least one of PEG-1000, PEG-1500, PPG-200, PPG-400 or PPG-600.

In the present invention, the rheological additive can play an activation and regulating role in anti-sagging. The amount of this component used is related to the construction temperature. The higher the construction temperature, the more the amount used.

Preferably, the preparation method of the rheological additive comprises the following steps:

The emulsifying dispersant is added into water and mixed evenly, and then the organic modified synthetic layered silicate is added and mixed evenly to obtain the rheological additive.

For example, under stirring at 400 rpm to 600 rpm, an emulsifying dispersant is added to water, the rotation speed is adjusted to 1000 rpm to 1500 rpm, and an organic-modified synthetic layered silicate is slowly added, and stirring is continued until the solution is clear and no dissolved particles are observed, thereby obtaining a rheological additive.

Preferably, the surface additive is BYK-3560.

In the present invention, BYK-3560 is a surface additive that does not contain silicone and fluorine, which can improve the surface energy of the cured coating (especially the polar coating) and improve the "wet-spray-wet" adhesion between the coating and the varnish; at the same time, it can effectively improve the wettability of the cured coating, so that the coating has excellent leveling properties; and BYK-3560 will not affect the surface tension of the liquid coating and maintain the high transparency of the varnish.

Preferably, the stabilizer is at least one of propylene glycol methyl ether acetate (PGMEA) or propylene glycol methyl ether propionate (PMP).

In the present invention, the preferred stabilizer can provide good solubility and fluidity, ensure uniform coating and easy construction, and improve the adhesion and durability of the coating.

For example, the preparation method of the activated diluent comprises the following steps:

Weigh the raw materials according to the designed ratio, add the aqueous cellulose acetate butyrate solution and the surface additive to the rheological additive at 600 rpm to 800 rpm, stir for 8 min to 12 min, then add the stabilizer, mix well, and obtain the activated diluent.

The present invention improves the tolerance of the system to the high content of surfactant or the limit film thickness and pH value of the base paint through the compound synergistic effect. The rheological additive can increase the low shear viscosity of the coating, prevent the coating from sagging or mixing during the "wet-on-wet" construction, further improve the construction performance and storage stability of the coating, and effectively prevent the sedimentation and dehydration shrinkage of solid matter in the water-based coating system; in addition, there is no need to adjust the pH value during the addition process, and it is effective for the formulations with pH values ranging from strong acid to strong base, which is particularly suitable for large-area construction spraying of rail transit vehicle bodies, accelerates the formation of the structure after construction, thereby achieving smooth construction under high temperature, low temperature or high humidity environments, and forming an ideal paint film surface state; the rheological properties can also effectively prevent the precipitation and dehydration shrinkage of the base paint, and improve the stability. The rheological additive, the surface additive and the aqueous cellulose acetate butyrate solution can form a synergistic effect, achieve a significant increase in interlayer adhesion and precise adjustment of the rheological properties, thereby improving the interlayer adhesion of the water-based solid color base paint and the clear coat varnish, and further preventing the clear coat varnish from "re-dissolving".

The present invention finds through a large number of tests that when the rheological additive is compounded with the surface additive, excessive use of the rheological additive will lead to poor water resistance of the water-based solid color base paint; when the rheological additive is compounded with the aqueous cellulose acetate butyrate solution, excessive use of the aqueous cellulose acetate butyrate solution will also lead to poor water resistance of the water-based solid color base paint; compounding the rheological additive with the surface additive and the aqueous cellulose acetate butyrate solution in a specific ratio can further improve the storage stability and water resistance of the coating, so that the appearance of the paint film reaches the best state, and no undesirable phenomena such as orange peel and prickly heat will occur.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

The water used in the embodiments of the present invention is deionized water.

The test instrument used in the present invention comprises:

Grid marker, Guangzhou Biaogeda;

Pencil hardness tester, impact instrument, bending tester, cupping tester, distinctness of image tester, BYK, Germany;

MA85 multi-angle wind photometer, X-Rite, USA;

ISO No. 6 cup, Tu-4# cup, solvent resistance wiper, pH meter, film thickness meter, Shanghai Modern Environmental Engineering Technology Co., Ltd.;

Salt spray resistance test equipment, artificial weathering resistance (QUA/SPARY), Q-Lab, USA.

In order to better illustrate the present invention, further examples are given below.

Example 1

This embodiment provides a water-based solid color base paint, which is composed of component A and component B in a mass ratio of 100:1.

Component A is composed of the following raw material components in percentage by mass: 18% of an aqueous aliphatic anionic polyurethane dispersion containing polycarbonate having a glass transition temperature of 40 to 50°C (denoted as PUD with Tg=40-50), 16% of an aqueous aliphatic anionic polyurethane dispersion having a glass transition temperature of ≤5°C (denoted as PUD with Tg≤5), 6% of an aqueous self-crosslinking low-hydroxy acrylate dispersion, 2% of a neutralizer, 3% of an aqueous cellulose acetate butyrate solution (denoted as CAB solution), 5% of a first cosolvent, 0.6% of a first surfactant, 0.6% of a substrate wetting agent, 0.6% of a leveling agent, 25.6% of an aqueous colorant, 0.6% of a first defoaming agent, 1% of a thickener and 21% of water.

Taking component A as 100%, the water-based color paste is composed of 10% water, 1.2% dispersant, 0.4% second defoamer, 0.8% second surfactant, 10% organic pigment, 3% color paste stabilizer and 0.2% neutralizer.

The aqueous cellulose acetate butyrate solution is composed of the following raw materials in percentage by mass: 20% aqueous cellulose acetate butyrate (referred to as CAB), 0.2% neutralizer and 79.8% medium solution, and the sum of the components is 100%.

Component B is composed of the following raw material components in percentage by mass: 75% of curing agent (28% of low viscosity hydrophobic hexamethylene diisocyanate, 27% of high viscosity hydrophilic hexamethylene diisocyanate and 20% of hydrophilic modified isophorone diisocyanate) and 25% of the second cosolvent.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the organic pigment is 0.048:1, and the solid content of component A is 27.8%.

The preparation method of the above-mentioned water-based solid color base paint comprises the following steps:

S1, weigh the raw materials according to the designed ratio, add the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40-50°C, the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C and the aqueous self-crosslinking low-hydroxy acrylate dispersion into a clean container, add water at 700rpm, and stir for 5min; then add the neutralizer to adjust the pH of the system to 8; then add the aqueous cellulose acetate butyrate solution, the first cosolvent, the first surfactant, the substrate wetting agent, the leveling agent, the aqueous color paste and the first defoaming agent in sequence, and continue to stir at 700rpm for 8min; finally add the thickener, mix well, and obtain component A.

S2, adding the curing agent into the second co-solvent, mixing evenly, to obtain component B.

Example 2

This embodiment provides a water-based solid color base paint, which is composed of component A. Among them,

Component A is composed of the following raw material components in percentage by mass: 21.4% of aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 10% of aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 3% of neutralizer, 2% of aqueous cellulose acetate butyrate solution, 6% of a first cosolvent, 1% of a first surfactant, 1% of a substrate wetting agent, 1% of a leveling agent, 22.1% of an aqueous color paste, 1% of a first defoamer, 1.5% of a thickener and 30% of water.

Taking component A as 100%, the water-based color paste is composed of 5% water, 1.4% dispersant, 0.5% second defoamer, 1% second surfactant, 13% organic pigment, 0.9% color paste stabilizer and 0.3% neutralizer.

The aqueous cellulose acetate butyrate solution is composed of the following raw materials in percentage by mass: 15% of aqueous cellulose acetate butyrate and 85% of medium solution, and the sum of the components is 100%.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the organic pigment is 0.043:1, and the solid content of component A is 27.8%.

The preparation method of the above-mentioned water-based solid color base paint comprises the following steps:

S1. Weigh the raw materials according to the designed ratio, add the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40-50°C and the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C into a clean container, add water at 600rpm, and stir for 6min; then add the neutralizer to adjust the pH of the system to 8.5; then add the aqueous cellulose acetate butyrate solution, the first cosolvent, the first surfactant, the substrate wetting agent, the leveling agent, the aqueous color paste and the first defoamer in sequence, and continue to stir at 600rpm for 10min; finally add the thickener, mix well, and obtain component A, i.e., the aqueous solid color base paint.

Example 3

This embodiment provides a water-based solid color base paint, which is composed of component A and component B in a mass ratio of 100:1.7.

Component A is composed of the following raw material components in percentage by mass: 20% aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 20% aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 10% aqueous self-crosslinking low-hydroxy acrylate dispersion, 3% neutralizer, 4% aqueous cellulose acetate butyrate solution, 5.2% first cosolvent, 0.9% first surfactant, 0.8% substrate wetting agent, 0.8% leveling agent, 24.8% aqueous color paste, 0.2% first defoamer, 0.3% thickener and 10% water.

Taking component A as 100%, the water-based color paste is composed of 14% water, 0.8% dispersant, 0.2% second defoamer, 0.2% second surfactant, 5% organic pigment, 4.5% color paste stabilizer and 0.1% neutralizer.

The aqueous cellulose acetate butyrate solution is composed of the following raw materials in percentage by mass: 25% aqueous cellulose acetate butyrate, 0.5% neutralizer and 74.5% medium solution, and the sum of the components is 100%.

Component B is composed of the following raw material components in percentage by mass: 73% of curing agent (30% of low viscosity hydrophobic hexamethylene diisocyanate, 25% of high viscosity hydrophilic hexamethylene diisocyanate and 18% of hydrophilic modified isophorone diisocyanate) and 27% of the second cosolvent.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the organic pigment is 0.064:1, and the solid content of component A is 26.7%.

The preparation method of the above-mentioned water-based solid color base paint comprises the following steps:

S1, weigh the raw materials according to the designed ratio, add the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40-50°C, the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C and the aqueous self-crosslinking low-hydroxy acrylate dispersion into a clean container, add water at 800rpm, and stir for 4min; then add the neutralizer to adjust the pH of the system to 8.5; then add the aqueous cellulose acetate butyrate solution, the first cosolvent, the first surfactant, the substrate wetting agent, the leveling agent, the aqueous color paste and the first defoamer in sequence, and continue to stir at 800rpm for 6min; finally add the thickener, mix well, and obtain component A.

S2 is the same as in Example 1 and will not be described in detail.

Example 4

This embodiment provides a water-based solid color base paint, which is composed of component A and component B in a mass ratio of 100:0.6.

Component A is composed of the following raw material components in percentage by mass: 16% aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 14% aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 3% aqueous self-crosslinking low-hydroxy acrylate dispersion, 1% neutralizer, 4% aqueous cellulose acetate butyrate solution, 5% first cosolvent, 0.7% first surfactant, 0.7% substrate wetting agent, 0.7% leveling agent, 35.6% aqueous color paste, 0.7% first defoamer, 0.9% thickener and 17.7% water.

Taking component A as 100%, the water-based color paste is composed of 8% water, 1.5% dispersant, 0.4% second defoamer, 0.4% second surfactant, 20% inorganic pigment, 5% color paste stabilizer and 0.3% neutralizer.

The raw material composition of the aqueous cellulose acetate butyrate solution is the same as that in Example 1 and will not be described in detail.

Component B is composed of the following raw material components in percentage by mass: 80% of curing agent (28% of low viscosity hydrophobic hexamethylene diisocyanate, 30% of high viscosity hydrophilic hexamethylene diisocyanate and 22% of hydrophilic modified isophorone diisocyanate) and 20% of the second cosolvent.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the inorganic pigment is 0.03:1, and the solid content of component A is 36.1%.

The preparation method of the above-mentioned water-based solid color base paint is the same as that in Example 1 and will not be repeated here.

Example 5

This embodiment provides a water-based solid color base paint, which is composed of component A. Among them,

Component A is composed of the following raw material components in percentage by mass: 25% of aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 16.5% of aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 1% of a neutralizer, 2% of an aqueous cellulose acetate butyrate solution, 3% of a first cosolvent, 0.3% of a first surfactant, 0.4% of a substrate wetting agent, 0.2% of a leveling agent, 34.1% of an aqueous color paste, 0.8% of a first defoamer, 0.7% of a thickener and 16% of water.

Taking component A as 100%, the water-based color paste is composed of 5% water, 1.8% dispersant, 0.2% second defoamer, 0.5% second surfactant, 25% inorganic pigment, 1.5% color paste stabilizer and 0.1% neutralizer.

The raw material composition of the aqueous cellulose acetate butyrate solution is the same as that in Example 1 and will not be described in detail.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the inorganic pigment is 0.03:1, and the solid content of component A is 42.1%.

The preparation method of the above-mentioned water-based solid color base paint is the same as that in Example 2 and will not be repeated here.

Example 6

This embodiment provides a water-based solid color base paint, which is composed of component A and component B in a mass ratio of 100:1.1.

Component A is composed of the following raw material components in percentage by mass: 15% aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 17% aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 8% aqueous self-crosslinking low-hydroxy acrylate dispersion, 2% neutralizer, 3% aqueous cellulose acetate butyrate solution, 4% first cosolvent, 0.2% first surfactant, 0.2% substrate wetting agent, 0.1% leveling agent, 35.9% aqueous color paste, 0.4% first defoamer, 1.2% thickener and 13% water.

Taking component A as 100%, the water-based color paste is composed of 12% water, 1.2% dispersant, 0.3% second defoamer, 0.2% second surfactant, 15% inorganic pigment, 7% color paste stabilizer and 0.2% neutralizer.

The raw material composition of the aqueous cellulose acetate butyrate solution is the same as that in Example 1 and will not be described in detail.

Component B is composed of the following raw material components in percentage by mass: 75% of curing agent (75% of low-viscosity hydrophobic hexamethylene diisocyanate) and 25% of the second co-solvent.

The specific components of the above raw materials are shown in Table 1. According to calculation, the mass ratio of the non-volatile matter of the dispersant to the inorganic pigment is 0.032:1, and the solid content of component A is 33.1%.

The preparation method of the above-mentioned water-based solid color base paint is the same as that in Example 1 and will not be repeated here.

Example 7

This embodiment provides a water-based solid color base paint, which is similar to Example 1, except that the dispersant is replaced by a nonionic wetting dispersant (DISPERBYK-190), the second cosolvent is replaced by PMA, PC and DMM in a mass ratio of 1:1:2, and the curing agent is replaced by a high-viscosity hydrophilic hexamethylene diisocyanate (Covestro Bayhydur305 and Covestro Bayhydrol XP 2547 in a mass ratio of 1:1). The remaining components are the same as in Example 1 and will not be repeated.

The preparation method of the above-mentioned water-based solid color base paint is the same as that in Example 1 and will not be repeated here.

Example 8

This embodiment provides a water-based solid color base paint, which is similar to Example 1, except that the dispersant is replaced by an anionic wetting dispersant (TEGO Dispers 747W), and the curing agent is replaced by water-based isophorone diisocyanate (Covestro Bayhydur 401-70). The remaining components are the same as those in Example 1 and will not be repeated.

The preparation method of the above-mentioned water-based solid color base paint is the same as that in Example 1 and will not be repeated here.

Table 1 Specific raw material components of water-based solid color base paint in Examples 1 to 6

Comparative Example 1

This comparative example provides a water-based solid color basecoat, which is similar to Example 1, except that Covestro Bayhydol UH 2606 is replaced with Covestro Bayhydrol A 2846 of equal quality (i.e., the water-based resin does not contain a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C.). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 2

This comparative example provides a water-based solid color base paint, which is similar to Example 4, except that Covestro Bayhydrol UH 2110 is replaced with Covestro Bayhydrol A 2846 of equal quality (i.e., the water-based resin does not contain a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 3

This comparative example provides a water-based solid color basecoat, which is similar to Example 1, except that Covestro Bayhydol UH 2606 and Bayhydrol UH 2952/1 are replaced with Covestro Bayhydrol A 2846 of equal quality (i.e., the water-based resin contains only water-based self-crosslinking low-hydroxyl acrylate dispersion). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 4

This comparative example provides a water-based solid color base paint, which is similar to Example 4, except that Covestro Bayhydrol UH 2110 and Bayhydrol A 2846 are replaced by Covestro Bayhydol UH 2606 of equal quality (i.e., the water-based resin contains only a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C.). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 5

This comparative example provides a water-based solid color basecoat, which is similar to Example 1, except that Covestro Bayhydol UH 2606 and Bayhydrol A 2846 are replaced by Covestro Bayhydrol UH 2952/1 of equal quality (i.e., the water-based resin contains only a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 6

This comparative example provides a water-based solid color base paint, which is similar to Example 4, except that the water-based resin (Covestro Bayhydol UH 2606, Bayhydrol UH 2110 and Bayhydrol A 2846) is replaced with Liangu Uacryl 4219 (acrylic emulsion). The remaining components are the same as those in Example 1 and are not described in detail.

Comparative Example 7

This comparative example provides a water-based solid color basecoat, which is similar to Example 1, except that Covestro Bayhydol UH 2606 and Bayhydrol A 2846 are replaced by allnex of equal quality. 6803 (water-based acrylic resin emulsion). The remaining components are the same as those in Example 1 and will not be described in detail.

Application Example 1

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 1 were mixed evenly, and an activated diluent was added and mixed evenly to obtain a construction coating with a solid content of 25%.

The activated diluent is composed of the following raw material components in mass percentage: 30% aqueous cellulose acetate butyrate solution, 51% rheological additive, 4% surface additive and 15% stabilizer. The rheological additive is composed of the following raw material components in mass percentage: 2% organic modified synthetic layered silicate, 2% emulsifying dispersant and 96% water.

It should be noted that the raw material components and proportions of the aqueous cellulose acetate butyrate solution in the activated diluent and the aqueous cellulose acetate butyrate solution in the A component of Example 1 are the same. The specific components of the remaining raw materials are shown in Table 2.

Application Example 2

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

The activated diluent was added to component A of Example 2 and mixed evenly to obtain a construction coating with a solid content of 24%.

The activated diluent is composed of the following raw material components in mass percentage: 28% aqueous cellulose acetate butyrate solution, 48% rheological additive, 4% surface additive and 20% stabilizer. The rheological additive is composed of the following raw material components in mass percentage: 2.5% organic modified synthetic layered silicate, 2.5% emulsifying dispersant and 95% water.

It should be noted that the raw material components and proportions of the aqueous cellulose acetate butyrate solution in the activated diluent and the aqueous cellulose acetate butyrate solution in component A of Example 2 are the same. The specific components of the remaining raw materials are shown in Table 2.

Application Example 3

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 3 were mixed evenly, and an activated diluent was added and mixed evenly to obtain a construction coating with a solid content of 23%.

The activated diluent is composed of the following raw material components in mass percentage: 31.5% aqueous cellulose acetate butyrate solution, 54% rheological additive, 4.5% surface additive and 10% stabilizer. The rheological additive is composed of the following raw material components in mass percentage: 1.5% organic modified synthetic layered silicate, 1.5% emulsifying dispersant and 97% water.

It should be noted that the raw material components and proportions of the aqueous cellulose acetate butyrate solution in the activated diluent and the aqueous cellulose acetate butyrate solution in the A component of Example 3 are the same. The specific components of the remaining raw materials are shown in Table 2.

Application Example 4

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 4 were mixed evenly, and an activated diluent was added and mixed evenly to obtain a construction coating with a solid content of 32%.

Among them, the raw material ratio of the activated diluent is the same as that of Application Example 1; the raw material components of the aqueous cellulose acetate butyrate solution and the aqueous cellulose acetate butyrate solution in component A of Example 1 are the same and will not be repeated; the specific components of the remaining raw materials are shown in Table 2.

Application Example 5

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

The activated diluent was added to component A of Example 5 and mixed evenly to obtain a construction coating with a solid content of 38%.

Among them, the raw material ratio of the activated diluent is the same as that of Application Example 1; the raw material components of the aqueous cellulose acetate butyrate solution and the aqueous cellulose acetate butyrate solution in component A of Example 1 are the same and will not be repeated; the specific components of the remaining raw materials are shown in Table 2.

Application Example 6

This application embodiment provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 6 were mixed evenly, and an activated diluent was added and mixed evenly to obtain a construction coating with a solid content of 28%.

Among them, the raw material ratio of the activated diluent is the same as that of Application Example 1; the raw material components of the aqueous cellulose acetate butyrate solution and the aqueous cellulose acetate butyrate solution in component A of Example 1 are the same and will not be repeated; the specific components of the remaining raw materials are shown in Table 2.

Application Examples 7-8

Application Examples 7 to 8 respectively provide a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Examples 7 to 8 were mixed evenly respectively, and an activated diluent was added and mixed evenly to obtain two groups of construction coatings each having a solid content of 25%.

The raw material components and proportions of the activated diluent are the same as those in Application Example 1 and will not be described in detail.

Table 2 Specific raw material components of the activated diluent in Application Examples 1 to 6

Application Comparative Examples 1 to 7

Comparative Examples 1 to 7 provide a method for using a water-based solid color base paint, respectively, comprising the following steps:

Components A and B of Comparative Examples 1 to 7 were mixed evenly, and activated diluent was added and mixed evenly to obtain 7 groups of construction coatings. Among them, the solid content of the construction coatings of Comparative Examples 1, 3, 5 and 7 was 25%, and the solid content of the construction coatings of Comparative Examples 2, 4 and 6 was 32%; the raw material components and proportions of the activated diluent were the same as those of Application Example 1, and will not be repeated.

Application Comparative Example 8

This application comparative example provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 1 were mixed evenly, and an activated diluent was added and mixed evenly to obtain a construction coating with a solid content of 15%. The activated diluent was the same as that of Application Example 1 and will not be described in detail.

Application Comparative Example 9

This application comparative example provides a method for using a water-based solid color base paint, comprising the following steps:

Component A and component B of Example 1 were mixed evenly, water was added, and the mixture was mixed evenly to obtain a construction coating having a solid content of 25%.

Application Comparative Example 10

This comparative application example provides a method for using a water-based solid color base paint, which is similar to the application example 1, except that the water-based cellulose acetate butyrate solution in the activation diluent is replaced with an equal amount of rheological additive. That is, the activation diluent is composed of the following raw material components in mass percentage: 81% rheological additive, 4% surface additive and 15% stabilizer. The remaining conditions are the same as those in the application example 1 (obtaining a construction coating with a solid content of 25%), and will not be repeated.

Performance Testing

The performance tests were conducted on the construction coatings provided in Application Examples 1 to 8 and Application Comparative Examples 1 to 10.

(1) The tinplate was polished with 400-500 mesh sandpaper, and the surface oil was removed with ethanol, and then the construction coatings provided in application examples 1-8 and application comparative examples 1-10 were applied, such as: the construction coatings provided in application examples 1-2, 6-8 and application comparative examples 1-4 were applied at high temperature and high humidity (38°C, RH=85%), and the construction coatings provided in application examples 3-5 and application comparative examples 5-10 were applied at low temperature and high humidity (0°C, RH=85%); the film thickness was 20μm-30μm, and the coating was baked at 60°C for 2h. The paint film color and appearance, drying time, impact resistance, bending test and cupping test of the obtained test sample were tested respectively, and the test standards are shown in Table 3, and the test results are shown in Tables 4-5.

(2) A WB07-1 intermediate coating (purchased from Beijing Yulin Chemical Co., Ltd.) was applied on a steel plate coated with a cathode electrophoretic paint (CED, model EcoTa8500, purchased from Shanghai Jinlitai Chemical Co., Ltd.) with a film thickness of 40 to 60 μm and baked at 60°C for 2 h; then the construction coatings provided in Application Examples 1 to 8 and Application Comparative Examples 1 to 10 were applied, such as: the construction coatings provided in Application Examples 1 to 2, 6 to 8 and Application Comparative Examples 1 to 4 were applied at high temperature and high humidity (38°C, RH=85%), and the construction coatings provided in Application Examples 3 to 5 and Application Comparative Examples 5 to 10 were applied at low temperature and high humidity (0°C, RH=85%); 2 to 3 coats were sprayed, each coat flashed for 5 to 10 min, pre-baked at 60°C for 10 min (the paint film was surface dry), and then a two-component polyurethane varnish (SB04-01, purchased from Beijing Yulin Chemical Co., Ltd.) was applied, and the varnish dry film thickness was 40 to 60 μm. The solvent wiping resistance, water resistance, gasoline resistance, acid resistance, acid resistance, alkali resistance and artificial climate accelerated aging resistance of the obtained test samples were tested respectively. The test standards are shown in Table 3, and the test results are shown in Tables 4 to 5.

Table 3 Performance test standards and requirements of the construction coatings provided in the application examples and comparative examples

Table 4 Performance test results of the construction coating provided by the application example

In the table:

Thixotropic index: measured using NDJ-1 rotational viscometer; the viscosity of component A (ISO6 ^# ) was adjusted to about 70s by the amount of thickener, and its low rotation (6r/min) viscosity and high rotation (60r/min) viscosity were measured. The calculation formula of the thixotropic index is: Thixotropic index (DI) = low rotation viscosity / high rotation viscosity.

Appearance effect evaluation: 0 is "excellent", 1 is "qualified", and the larger the number is, the worse it is. 0-smooth and delicate; 1-not delicate enough; 2-slightly orange peel; 3-rough paint film with many pits; 4-obvious orange peel, paint film with prickly heat.

Construction performance: 0 is "excellent", 1 is "qualified", and the larger the number is, the worse it is. 0-no orange peel, no sag; 1-slight orange peel; 2-slight sag; 3-slight orange peel and slight sag; 4-poor fluidity; 5-severe orange peel and severe sag.

Cross-cut test: 0 means "excellent", 1 means "qualified", and the larger the number is, the worse it is. 0-The substrate is not polished, and the adhesion is excellent; the rest is based on the cross-cut test standard GB/T9286-1998 "Cross-cut test for paint and varnish film".

Table 5 Performance test results of the construction coating provided by the comparative example

In summary, the water-based solid color base paint provided by the present invention, component A selects a water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a high glass transition temperature and a water-based aliphatic anionic polyurethane dispersion with a low glass transition temperature for compounding as a film-forming resin, and selectively adds a water-based self-crosslinking low-hydroxyl acrylate dispersion, and through a specific ratio and the synergistic effect of each component, the characteristics of different types of water-based resins are brought into play to the best state, so that the final water-based solid color base paint has good gloss and thixotropy, and does not fly ash when sprayed on a large area, the gun is well mounted, the thixotropy is improved, and the flexibility and hardness of the cured film are balanced at the same time, which can effectively solve the problem of the difficulty of "wet spray wet" matching coating construction in the "water-based solid color base paint + varnish" system, and can be constructed on a large area under high temperature, low temperature or high humidity. The present invention obtains a water-based solid color base paint with excellent comprehensive performance through the synergistic effect of each raw material component and a specific ratio content, which has high practical value and promotion value.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A water-based solid color base paint, characterized in that it is composed of component A and component B in a mass ratio of 100: (0-10); wherein, The A component comprises the following raw material components in mass percentage: 10% to 25% of an aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, 10% to 20% of an aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C, 0% to 10% of an aqueous self-crosslinking low-hydroxy acrylate dispersion, 1% to 3% of a neutralizer, 2% to 4% of an aqueous cellulose acetate butyrate solution, 3% to 6% of a first cosolvent, 0.2% to 1% of a first surfactant, 0.2% to 1% of a substrate wetting agent, 0.1% to 1% of a leveling agent, 12% to 45% of an aqueous color paste, 0.2% to 1% of a first defoamer, 0.3% to 1.5% of a thickener, and 10% to 30% of water; the aqueous color paste comprises water, a dispersant, a second defoamer, a second surfactant, a pigment, a color paste stabilizer, and a neutralizer; The B component includes the following raw material components in percentage by mass: 70% to 80% of a curing agent and 20% to 30% of a second co-solvent; the curing agent is at least one of hexamethylene diisocyanate or a hydrophilic aliphatic polyisocyanate. 2. The water-based solid color base paint according to claim 1, characterized in that the solid contents of the water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50°C, the water-based aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5°C and the water-based self-crosslinking low-hydroxy acrylate dispersion are all 34% to 41%; The hydroxyl content of the aqueous self-crosslinking low-hydroxyl acrylate dispersion is 1% to 2%. 3. The water-based solid color base paint according to claim 1, characterized in that the water-based polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C. is Bayhydol UH 2606 produced by Covestro; The aqueous self-crosslinking low-hydroxyl acrylate dispersion is Bayhydrol A 2846 produced by Covestro; The aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5° C. is at least one of Bayhydrol UH2648/1, Bayhydrol UH 2110, Bayhydrol UH 2621 or Bayhydrol UH2952/1. 4. The water-based solid color base paint according to claim 1, characterized in that, based on 100% of the component A, the water-based color paste comprises 5% to 14% of water, 0.8% to 1.4% of a dispersant, 0.2% to 0.5% of a second defoamer, 0.2% to 1% of a second surfactant, 5% to 13% of an organic pigment, 0.9% to 4.5% of a color paste stabilizer, and 0.1% to 0.3% of a neutralizer; or Taking the A component as 100%, the aqueous color paste includes 5% to 12% water, 1.2% to 1.8% dispersant, 0.2% to 0.5% second defoamer, 0.2% to 0.5% second surfactant, 15% to 25% inorganic pigment, 1.5% to 7% color paste stabilizer and 0.1% to 0.3% neutralizer. 5. The water-based solid color base paint according to claim 1, characterized in that the water-based cellulose acetate butyrate solution comprises the following raw material components in mass percentage: 15% to 25% of water-based cellulose acetate butyrate, 0% to 0.5% of neutralizer and 74.5% to 85% of medium solution, and the sum of the components is 100%; wherein, The aqueous cellulose acetate butyrate is Eastman Solus 3050; The medium solution is at least one of ethylene glycol butyl ether aqueous solution, propylene glycol methyl ether aqueous solution, dipropylene glycol dimethyl ether aqueous solution, N-methyl pyrrolidone aqueous solution, dimethyl sulfoxide aqueous solution, dimethylformamide aqueous solution, N-methylformamide aqueous solution or tetrahydrofuran aqueous solution; the mass concentration of the medium solution is 50% to 75%. 6. The water-based solid color base paint according to claim 1, characterized in that, based on 100% of the B component, the curing agent comprises 25% to 30% of low-viscosity hydrophobic hexamethylene diisocyanate, 25% to 30% of high-viscosity hydrophilic hexamethylene diisocyanate and 18% to 22% of hydrophilic modified isophorone diisocyanate; wherein, The low-viscosity hydrophobic hexamethylene diisocyanate is at least one of Covestro Desmodur N3900, Covestro Desmodur N3600 or Wanhua WANNATE HT-600; The high-viscosity hydrophilic hexamethylene diisocyanate is at least one of Covestro Bayhydrol XP 2655, Covestro Bayhydur XP 2547, Covestro Bayhydur XP 2487/1, Covestro Bayhydur 304 or Covestro Bayhydur 305; The hydrophilic aliphatic polyisocyanate is at least one of Covestro Bayhydur 401-70 and Covestro Bayhydur 401-60. 7. The water-based solid color base paint according to any one of claims 1 to 6, characterized in that the first cosolvent comprises at least three of dipropylene glycol dimethyl ether, propylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol methyl ether, dimethyl sulfoxide, N-methylpyrrolidone, diethylene glycol monobutyl ether or dipropylene glycol butyl ether; The second cosolvent is at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether acrylate, propylene carbonate, propylene glycol diacetate, ethylene glycol butyl ether acetate, dibasic acid ester or dipropylene glycol dimethyl ether; The dispersant is at least one of a nonionic wetting dispersant or an anionic wetting dispersant; The second surfactant is at least one of an acetylenic glycol surfactant or an alcohol alkoxy compound; The color paste stabilizer includes at least three of water-based fumed silica, modified urea rheological additive, resin-free color paste moisturizer or anti-drying agent for water-based pigment concentrate; The neutralizing agent is an aqueous solution of 8wt% to 12wt% dimethylethanolamine; The first surfactant is a gemini acetylenic diol surfactant; The substrate wetting agent is a polyether-modified silicone surfactant; The thickener is a polyurethane associative thickener. 8. The method for preparing the water-based solid color base paint according to any one of claims 1 to 7, characterized in that it comprises the following steps: S1, weighing various raw materials according to the designed ratio, mixing the aqueous polycarbonate-containing aliphatic anionic polyurethane dispersion with a glass transition temperature of 40 to 50° C., the aqueous aliphatic anionic polyurethane dispersion with a glass transition temperature of ≤5° C., and the aqueous self-crosslinking low-hydroxy acrylate dispersion, adding water and a neutralizing agent; then sequentially adding an aqueous cellulose acetate butyrate solution, a first cosolvent, a first surfactant, a substrate wetting agent, a leveling agent, an aqueous color paste, a first defoamer, and a thickener, mixing evenly, and obtaining component A; S2, adding the curing agent into the second co-solvent, mixing evenly, to obtain component B. 9. Use of the water-based solid color base paint according to any one of claims 1 to 7 or the water-based solid color base paint prepared by the preparation method of the water-based solid color base paint according to claim 8 in automotive coatings. 10. A method for using the water-based solid color base paint according to any one of claims 1 to 7 or the water-based solid color base paint prepared by the method for preparing the water-based solid color base paint according to claim 8, characterized in that it comprises the following steps: The components A and B are mixed evenly, and an activating diluent is added and mixed evenly to obtain a construction coating with a solid content of 20% to 40%, which is evenly applied to a metal substrate or a mid-coat; the activating diluent comprises an aqueous cellulose acetate butyrate solution, a rheological additive, a surface additive and a stabilizer; wherein, The activation diluent comprises the following raw material components in percentage by mass: 28% to 31.5% of aqueous cellulose acetate butyrate solution, 48% to 54% of rheological additive, 4% to 4.5% of surface additive and 10% to 20% of stabilizer, the sum of the components being 100%; The rheological additive comprises the following raw material components in percentage by mass: 1.5% to 2.5% of organic modified synthetic layered silicate, 1.5% to 2.5% of emulsifying dispersant and 95% to 97% of water, and the sum of the components is 100%.