Quick-drying double-component water-based paint and preparation process thereof

Abstract

The invention relates to a quick-drying double-component water-based paint and a preparation process thereof, and belongs to the technical field of water-based paints.The quick-drying double-component water-based paint comprises a component A and a component B. The component A comprises 50-60 parts of water-based acrylic emulsion, 0.5-1 part of dispersing agent, 0.2-0.5 part of defoaming agent, 10-15 parts of pigment, 5-10 parts of filler and 0-0.5 part of coalescing agent, and the component B comprises 10-15 parts of water-based isocyanate curing agent. The water-based acrylic emulsion with a core-shell structure is adopted, the dibutyl maleate and the polyacrylamide are used for wrapping the water-based acrylic emulsion, the sensitivity of the emulsion to low temperature can be reduced, and the stability of the emulsion can be guaranteed in the storage process.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based paints, and in particular relates to a quick-drying two-component water-based paint and a preparation process thereof. Background Art

[0002] Water-based acrylic emulsion is a system with water as the dispersion medium. Water-based acrylic emulsion is sensitive to temperature. In a low temperature environment, the structure of the emulsion may be destroyed, causing the emulsion to lose its original performance, such as gelation and failure to form a normal film. Water-based acrylic emulsion may react with some substances. For example, it is sensitive to certain pigments, which will cause the stability of the emulsion to decrease. During storage, the presence of water may cause microorganisms (such as bacteria, molds, and yeasts) to multiply in the emulsion, which may cause the emulsion to deteriorate. For example, bacterial metabolites may change the pH value of the emulsion, and acidic substances produced by some bacteria may reduce the pH value of the emulsion and affect the stability of the emulsion. In addition, the growth of microorganisms may also cause the emulsion to have odor, discoloration, and even flocculation and stratification.

[0003] Moreover, for furniture manufacturing, metal product processing, indoor and outdoor building painting, and equipment external protection, water-based paint is required to have the effects of quick drying, antibacterial, and flame retardant. However, the drying of water-based paint depends on the volatilization of water and has limitations. The use of antibacterial agents and flame retardants will also affect the mechanical properties and weather resistance of water-based paint. Summary of the invention

[0004] The purpose of the present invention is to provide a quick-drying two-component water-based paint and a preparation process thereof in order to solve the above-mentioned problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: The first object of the present invention is to provide a quick-drying two-component water-based paint, comprising component A and component B, wherein component A comprises, by weight: 50-60 parts of water-based acrylic emulsion, 0.5-1 parts of dispersant, 0.2-0.5 parts of defoamer, 10-15 parts of pigment, 5-10 parts of filler, and 0-0.5 parts of film-forming aid; Component B includes: 10-15 parts of water-based isocyanate curing agent; Wherein, the preparation method of water-based acrylic emulsion comprises the following steps: The emulsifier is dissolved in deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate are added, and stirred at high speed to obtain a core pre-emulsion; the emulsifier is dissolved in deionized water and stirred evenly, and dibutyl maleate and polyacrylamide are added, and stirred at high speed to obtain a shell pre-emulsion; Put an emulsifier, an initiator, and sodium bicarbonate into a reaction kettle, add deionized water, stir thoroughly, then add the nuclear pre-emulsion, slowly heat up the reaction, and when obvious blue fluorescence appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, keep warm after the dropwise addition, and the nuclear emulsion is obtained; The shell pre-emulsion and the initiator solution are added dropwise to the core emulsion, and after the addition is completed, the solution is kept warm, cooled, and filtered to obtain an aqueous acrylic emulsion with a core-shell structure.

[0006] As a further improvement of the present invention, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate is 10-20%:40-50%:30-40% by mass percentage.

[0007] As a further improvement of the present invention, the preparation process of the initiator solution is to add the initiator and sodium bicarbonate into deionized water and stir to dissolve them; wherein the initiator is one of benzoyl peroxide and ammonium persulfate, and the mass concentration of the initiator is 1-3wt%.

[0008] As a further improvement of the present invention, the mass ratio of dibutyl maleate and polyacrylamide as a whole to acrylic acid, methyl methacrylate and butyl acrylate as a whole is 10-30%:70-90% by mass percentage.

[0009] As a further improvement of the present invention, the mass ratio of polyacrylamide to dibutyl maleate is 10-20%:80-90% by mass percentage.

[0010] As a further improvement of the present invention, the preparation of the shell emulsion also includes adjusting the pH of the shell pre-emulsion system to 7.6-8.5 using sodium hydroxide.

[0011] As a further improvement of the present invention, modified dibutyl maleate is used to replace dibutyl maleate in the preparation method of the aqueous acrylic emulsion. The preparation steps of the modified polydibutyl maleate are as follows: First, dissolve butyl acrylate, dibutyl maleate and vinyl acetate in an appropriate amount of acetone in a mass ratio of (2.2-4.8):1:(3.1-6.5), react at 70°C for 5 hours and at 80°C for 1 hour under the initiation of benzoyl peroxide, then cool to 30°C, add 1-3% of the total system mass of chlorinated paraffin, and freeze-dry to obtain the product.

[0012] As a further improvement of the present invention, modified polyacrylamide is used to replace the polyacrylamide in the preparation method of the aqueous acrylic emulsion. The preparation steps of the modified polyacrylamide are as follows: The triethyl phosphate and methyl methacrylate are mixed, and a precursor solution is obtained under the initiation of benzoyl peroxide; anionic polyacrylamide is dissolved in water, and a formaldehyde aqueous solution is added to react to obtain a mixture, and the precursor solution is added to the mixture to react to obtain a reactant, which is washed with water and freeze-dried to obtain.

[0013] As a further improvement of the present invention, based on the triethyl phosphate, the volume fraction of the methyl methacrylate is 4-5 vol%, and the amount of the benzoyl peroxide is 1-2wt%.

[0014] The second object of the present invention is to provide a preparation process of a quick-drying two-component water-based paint, comprising the following steps: Add pigment, filler and dispersant into the agitator, disperse at a speed of 1000-1500 rpm for 10-20 minutes until a fine color paste is formed, reduce the speed to 500-800 rpm, slowly add water-based acrylic emulsion into the color paste, stir at a speed of 300-500 rpm for 10-15 minutes, add defoamer and film-forming aid, stir at a speed of 300-500 rpm for 3-5 minutes to evenly disperse them in the system, obtain component A, filter and package for storage; Mix component A and component B, stir at 300-500 rpm for 3-5 minutes, and the mixed components will be the water-based paint to be sprayed.

[0015] The beneficial effects of the present invention are: (1) The present invention adopts a water-based acrylic emulsion with a core-shell structure and uses dibutyl maleate and polyacrylamide to encapsulate the water-based acrylic emulsion, which can reduce the sensitivity of the emulsion to low temperatures and ensure the stability of the emulsion during storage.

[0016] (2) The present invention uses modified dibutyl maleate to encapsulate the water-based acrylic emulsion, which may participate in the cross-linking reaction during the film-forming process of the water-based paint, forming a more stable polymer network structure, improving the weather resistance of the water-based paint, and also playing a flame retardant role to a certain extent.

[0017] (3) The present invention also uses modified polyacrylamide to encapsulate the water-based acrylic emulsion, which can be very stably adsorbed on the water-based acrylic emulsion, greatly improving the stability of the emulsion, and can also improve the hardness and construction performance of the water-based paint.

[0018] (4) Two-component water-based paint is used. Compared with single-component water-based paint, which mainly relies on water evaporation to dry, the chemical reaction-driven drying process of two-component water-based paint is faster. DETAILED DESCRIPTION

[0019] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] 1. Materials The defoamer used in the present invention is BYK polysiloxane defoamer, the dispersant used is polyacrylic acid sodium salt dispersant, the emulsifier used is SDS emulsifier, the film-forming aid used is Texanol film-forming agent, the pigment used is titanium dioxide (rutile type), and the filler used is mica powder (80-200 mesh).

[0021] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art, and the reagents and other materials used are commercially available products unless otherwise specified.

[0022] 2. Methods Example 1 (1) The preparation method of the aqueous acrylic emulsion comprises the following steps: The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 15%:45%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. The emulsifier is dissolved in an appropriate amount of deionized water and stirred evenly, and then dibutyl maleate and polyacrylamide are added, and stirred at a high speed for 20 minutes to obtain a shell pre-emulsion. In terms of mass percentage, the mass ratio of polyacrylamide to dibutyl maleate is 20%:80%, and the amount of the emulsifier is 5% of the total mass of dibutyl maleate and polyacrylamide; Put emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence phenomenon appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, drop for 2h, keep warm for 4h after the dropwise addition, and the nuclear emulsion is obtained; In terms of mass percentage, the mass ratio of dibutyl maleate and polyacrylamide as a whole to acrylic acid, methyl methacrylate and butyl acrylate as a whole is 10%:90%. The shell pre-emulsion and initiator solution are added dropwise to the core emulsion according to the above mass ratio for 2 hours. After the addition is completed, the mixture is kept at 80°C (±5°C) for 4 hours, cooled and filtered to obtain an aqueous acrylic emulsion with a core-shell structure and a solid content of 45%.

[0023] (2) The preparation method of component A comprises the following steps: Add 15 parts of pigment, 10 parts of filler and 1 part of dispersant into the agitator, disperse at 1200 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.2 parts of defoamer and 0.5 parts of film-forming aid, stir at 300 rpm for 5 minutes to evenly disperse them in the system, and obtain component A.

[0024] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0025] Example 2 (1) The preparation method of the aqueous acrylic emulsion comprises the following steps: The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 10%:50%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, and then dibutyl maleate and polyacrylamide were added, and the shell pre-emulsion was obtained by high-speed stirring for 20 minutes. The pH of the shell pre-emulsion system was adjusted to 8.1 with sodium hydroxide. The mass ratio of polyacrylamide to dibutyl maleate was 20%:80% by mass percentage, and the amount of the emulsifier was 5% of the total mass of dibutyl maleate and polyacrylamide. Put emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence phenomenon appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, drop for 2h, keep warm for 4h after the dropwise addition, and the nuclear emulsion is obtained; In terms of mass percentage, the mass ratio of dibutyl maleate and polyacrylamide as a whole to acrylic acid, methyl methacrylate and butyl acrylate as a whole is 10%:90%. The shell pre-emulsion and the initiator solution are added dropwise to the core emulsion according to the above mass ratio for 2 hours. After the addition, the mixture is kept at 80°C (±5°C) for 4 hours, cooled and filtered to obtain an aqueous acrylic emulsion with a core-shell structure and a solid content of 48%.

[0026] (2) The preparation method of component A comprises the following steps: Add 15 parts of pigment, 10 parts of filler and 1 part of dispersant into the agitator, disperse at 1200 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.2 parts of defoamer and 0.5 parts of film-forming aid, stir at 300 rpm for 5 minutes to evenly disperse them in the system, and obtain component A.

[0027] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0028] Example 3 (1) The preparation method of the aqueous acrylic emulsion comprises the following steps: First, butyl acrylate, dibutyl maleate and vinyl acetate were dissolved in a proper amount of acetone in a mass ratio of 2.6:1:3.1, and reacted at 70°C for 5 hours and at 80°C for 1 hour under the initiation of a proper amount of benzoyl peroxide, and then cooled to 30°C, and 1% of the total system mass of chlorinated paraffin was added, and the modified polydibutyl maleate was obtained by freeze drying at 40°C for 24 hours; The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 10%:50%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, and then modified dibutyl maleate and polyacrylamide were added, and the shell pre-emulsion was obtained by high-speed stirring for 20 minutes. The pH of the shell pre-emulsion system was adjusted to 8.1 with sodium hydroxide. The mass ratio of polyacrylamide to modified dibutyl maleate was 20%:80% by mass percentage, and the amount of the emulsifier was 5% of the total mass of modified dibutyl maleate and polyacrylamide. Put emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence phenomenon appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, drop for 2h, keep warm for 4h after the dropwise addition, and the nuclear emulsion is obtained; The mass percentage of modified dibutyl maleate and polyacrylamide to acrylic acid, methyl methacrylate and butyl acrylate is 10%:90%. The shell pre-emulsion and initiator solution are added dropwise to the core emulsion according to the above mass ratio for 2 hours. After the addition, the mixture is kept at 80°C (±5°C) for 4 hours, cooled and filtered to obtain an aqueous acrylic emulsion with a core-shell structure and a solid content of 51%.

[0029] (2) The preparation method of component A comprises the following steps: Add 15 parts of pigment, 10 parts of filler and 0.7 parts of dispersant into the agitator, disperse at 1200 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.2 parts of defoamer and 0.2 parts of film-forming aid, stir at 300 rpm for 5 minutes to evenly disperse them in the system, and obtain component A.

[0030] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0031] Example 4 (1) The preparation method of the aqueous acrylic emulsion comprises the following steps: Triethyl phosphate and methyl methacrylate are mixed, and a precursor solution is obtained under the initiation of benzoyl peroxide, wherein the volume fraction of methyl methacrylate is 4 vol% based on triethyl phosphate, and the amount of benzoyl peroxide is 1wt%; anionic polyacrylamide is dissolved in water to obtain a solution with a mass concentration of 2wt%, and then a sufficient amount of a 40% formaldehyde aqueous solution is added to react to obtain a mixture, and an equal volume of the precursor solution is added to the mixture to react to obtain a reactant, which is washed with water at 45°C and freeze-dried at 40°C to obtain modified polyacrylamide; The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 10%:50%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, and then dibutyl maleate and modified polyacrylamide were added, and the shell pre-emulsion was obtained by high-speed stirring for 20 minutes. The pH of the shell pre-emulsion system was adjusted to 8.1 with sodium hydroxide. The mass ratio of modified polyacrylamide and dibutyl maleate was 20%:80% by mass percentage, and the amount of the emulsifier was 5% of the total mass of dibutyl maleate and modified polyacrylamide. Put emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence phenomenon appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, drop for 2h, keep warm for 4h after the dropwise addition, and the nuclear emulsion is obtained; The mass percentage of dibutyl maleate and modified polyacrylamide to acrylic acid, methyl methacrylate and butyl acrylate is 20%:80%. The shell pre-emulsion and initiator solution are added dropwise to the core emulsion according to the above mass ratio for 2 hours. After the addition, the mixture is kept at 80°C (±5°C) for 4 hours, cooled and filtered to obtain an aqueous acrylic emulsion with a core-shell structure and a solid content of 52%.

[0032] (2) The preparation method of component A comprises the following steps: Add 15 parts of pigment, 10 parts of filler and 0.8 parts of dispersant into the agitator, disperse at 1200 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.2 parts of defoamer and 0.1 parts of film-forming aid, stir at 300 rpm for 5 minutes to evenly disperse them in the system, and obtain component A.

[0033] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0034] Example 5 (1) The preparation method of the aqueous acrylic emulsion comprises the following steps: First, butyl acrylate, dibutyl maleate and vinyl acetate were dissolved in a proper amount of acetone in a mass ratio of 2.6:1:3.1, and reacted at 70°C for 5 hours and at 80°C for 1 hour under the initiation of a proper amount of benzoyl peroxide, and then cooled to 30°C, and 1% of the total system mass of chlorinated paraffin was added, and the modified polydibutyl maleate was obtained by freeze drying at 40°C for 24 hours; Triethyl phosphate and methyl methacrylate are mixed, and a precursor solution is obtained under the initiation of benzoyl peroxide, wherein the volume fraction of methyl methacrylate is 4 vol% based on triethyl phosphate, and the amount of benzoyl peroxide is 1wt%; anionic polyacrylamide is dissolved in water to obtain a solution with a mass concentration of 2wt%, and then a sufficient amount of a 40% formaldehyde aqueous solution is added to react to obtain a mixture, and an equal volume of the precursor solution is added to the mixture to react to obtain a reactant, which is washed with water at 45°C and freeze-dried at 40°C to obtain modified polyacrylamide; The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 10%:50%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, and then modified dibutyl maleate and modified polyacrylamide were added, and the shell pre-emulsion was obtained by high-speed stirring for 20 minutes. The pH of the shell pre-emulsion system was adjusted to 8.1 with sodium hydroxide. The mass ratio of modified polyacrylamide and modified dibutyl maleate was 20%:80% by mass percentage, and the amount of emulsifier was 5% of the total mass of modified dibutyl maleate and modified polyacrylamide. Put emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence phenomenon appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, drop for 2h, keep warm for 4h after the dropwise addition, and the nuclear emulsion is obtained; In terms of mass percentage, the mass ratio of modified dibutyl maleate and modified polyacrylamide to acrylic acid, methyl methacrylate and butyl acrylate is 20%:80%. The shell pre-emulsion and initiator solution are added dropwise to the core emulsion according to the above mass ratio for 2 hours. After the addition, the mixture is kept at 80°C (±5°C) for 4 hours, cooled and filtered to obtain an aqueous acrylic emulsion with a core-shell structure and a solid content of 55%.

[0035] (2) The preparation method of component A comprises the following steps: Add 15 parts of pigment, 10 parts of filler and 0.5 parts of dispersant into the agitator, disperse at 1200 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.2 parts of defoamer, stir at 300 rpm for 5 minutes to evenly disperse it in the system, and obtain component A.

[0036] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0037] Comparative Example 1 The emulsifier was dissolved in an appropriate amount of deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate were added, and stirred at high speed for 30 minutes to obtain a nuclear pre-emulsion. In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate was 10%:50%:40%, and the amount of the emulsifier was 5% of the total mass of acrylic acid, methyl methacrylate and butyl acrylate; Add benzoyl peroxide and sodium bicarbonate into an appropriate amount of deionized water, stir at room temperature to dissolve them, and obtain an initiator solution. The mass concentration of benzoyl peroxide is 2wt%, and the amount of sodium bicarbonate is 0.1% of the mass of the initiator solution. Place emulsifier, benzoyl peroxide and sodium bicarbonate into a reactor and add appropriate amount of deionized water, the amount of emulsifier is 1% of the mass of the nuclear pre-emulsion, the amount of benzoyl peroxide is 0.1% of the mass of the nuclear pre-emulsion, the amount of sodium bicarbonate is 0.1% of the mass of the nuclear pre-emulsion, stir well, then add the nuclear pre-emulsion, slowly heat to 80±5℃ for reaction, when obvious blue fluorescence appears, the seed emulsion is obtained; continue to add the remaining nuclear pre-emulsion and initiator solution dropwise to the seed emulsion, add dropwise for 2h, and keep warm for 4h after the addition is completed to obtain a water-based acrylic emulsion with a solid content of 42%.

[0038] Add 15 parts of pigment, 10 parts of filler and 2 parts of dispersant into the agitator, disperse at 1500 rpm for 10 minutes until a fine color paste is formed, reduce the stirring speed to 500 rpm, slowly add 60 parts of water-based acrylic emulsion into the color paste, stir at 500 rpm for 10 minutes, add 0.5 parts of defoamer and 0.5 parts of film-forming aid, stir at 300 rpm for 5 minutes to evenly disperse them in the system, and obtain component A.

[0039] Mix component A and 15 parts of component B water-based isocyanate curing agent, stir at 300 rpm for 3 minutes, and the mixed product is the water-based paint to be sprayed.

[0040] Comparative Example 2 On the basis of Example 3, when the dibutyl maleate modification was performed, no chlorinated paraffin was added, and the rest was the same as Example 3.

[0041] Comparative Example 3 On the basis of Example 4, triethyl phosphate was not added during the polyacrylamide modification, and the rest was the same as Example 4.

[0042] 3. Water-based paint test Drying speed: According to standard GB / T 1728-2020 "Determination of drying time of paint film and putty film".

[0043] Low temperature resistance: In an experimental environment with a temperature of 0°C and a humidity of 40-55%, each sample was coated on a glass substrate with a coating thickness of 100μm, and the film appearance and actual drying time were tested.

[0044] Weather resistance: The paint film is coated on a glass sheet, and a border is drawn on the surface of the paint film. Then the sample is immersed in a container containing 40°C water and 10% H2SO4. The samples are taken out after 96 hours (water) and 24 hours (H2SO4), and the changes on the paint film surface, such as blistering and shedding, are observed under an optical microscope.

[0045] Antibacterial property: tested in accordance with the standard GB / T21866-2008 "Determination of antibacterial property and antibacterial effect of antibacterial water-based paint (paint film)"; Flame retardancy: The water-based paint of each sample is coated on the glass substrate with a coating thickness of 0.5 mm. The coated samples need to be dried to constant weight at a temperature of 23±2°C and a relative humidity of 50±5%, and then the limiting oxygen index of the water-based paint is tested using an oxygen index meter.

[0046] Hardness: According to the standard GB / T 6739 "Paint and varnish pencil method for determination of paint film hardness".

[0047] The test results of Examples 1-5 and Comparative Examples 1-3 are shown in the following table: By comparing the test performance results in the above table, the following analysis conclusions can be drawn. By comparing Examples 1-2 and Comparative Example 1, it can be seen that the aqueous acrylic emulsion with a core-shell structure of the present invention uses dibutyl maleate and polyacrylamide to encapsulate the aqueous acrylic emulsion, which can reduce the sensitivity of the emulsion to low temperatures, and during storage, the stability of the emulsion can be guaranteed. The reason is speculated that dibutyl maleate, as an internal plasticizing monomer, can reduce the film-forming temperature of the acrylic emulsion, making the emulsion particles more easily deformed and aggregated to form a continuous film, thereby accelerating the film-forming speed and improving the cohesion and mechanical properties of the emulsion; the three-dimensional network structure formed by polyacrylamide in the aqueous acrylic emulsion can limit the penetration of water. At the same time, some groups on its molecular chain can interact with the polymer in the emulsion, making the structure of the polymer more compact and reducing the channel for water to enter the emulsion. Adjusting the pH of the shell emulsion to 7.6-8.5 can make polyacrylamide more compatible with the aqueous acrylic emulsion, better adsorption effect, stronger encapsulation, and conducive to the water resistance and antibacterial properties of the water-based paint.

[0048] The present invention uses modified dibutyl maleate to wrap the water-based acrylic emulsion, so that the modified dibutyl maleate may participate in the cross-linking reaction in the film-forming process of the water-based paint to form a more stable polymer network structure, thereby improving the weather resistance of the water-based paint. It can be seen from Comparative Example 2 that the added chlorinated paraffin can also play a flame retardant role to a certain extent, thereby increasing the construction performance of the water-based paint.

[0049] The present invention also uses modified polyacrylamide to wrap the water-based acrylic emulsion, further enhancing its adsorption, and can be very stably adsorbed on the water-based acrylic emulsion, greatly improving the stability of the emulsion, and can improve the hardness and construction performance of the water-based paint. Triethyl phosphate is a commonly used insecticide component in pesticides, which can effectively inhibit and remove bacteria and fungi. It is used to modify and compound polyacrylamide. It can be seen from Comparative Example 3 that the antibacterial and flame retardant properties of the water-based paint are further improved.

[0050] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A quick-drying two-component water-based paint, comprising component A and component B, characterized in that: By weight: Component A includes: 50-60 parts of water-based acrylic emulsion, 0.5-1 parts of dispersant, 0.2-0.5 parts of defoamer, 10-15 parts of pigment, 5-10 parts of filler, and 0-0.5 parts of film-forming aid; Component B includes: 10-15 parts of water-based isocyanate curing agent; Wherein, the preparation method of water-based acrylic emulsion comprises the following steps: The emulsifier is dissolved in deionized water and stirred evenly, acrylic acid, methyl methacrylate and butyl acrylate are added, and stirred at high speed to obtain a core pre-emulsion; the emulsifier is dissolved in deionized water and stirred evenly, and dibutyl maleate and polyacrylamide are added, and stirred at high speed to obtain a shell pre-emulsion; Put an emulsifier, an initiator, and sodium bicarbonate into a reaction kettle, add deionized water, stir thoroughly, then add the nuclear pre-emulsion, slowly heat up the reaction, and when obvious blue fluorescence appears, the seed emulsion is obtained; continue to drop the remaining nuclear pre-emulsion and initiator solution into the seed emulsion, keep warm after the dropwise addition, and the nuclear emulsion is obtained; The shell pre-emulsion and the initiator solution are added dropwise to the core emulsion, and after the addition is completed, the solution is kept warm, cooled, and filtered to obtain an aqueous acrylic emulsion with a core-shell structure.

2. A quick-drying two-component water-based paint according to claim 1, characterized in that: In terms of mass percentage, the mass ratio of acrylic acid, methyl methacrylate and butyl acrylate is 10-20%: 40-50%: 30-40%.

3. A quick-drying two-component water-based paint according to claim 1, characterized in that: The preparation process of the initiator solution is to add the initiator and sodium bicarbonate into deionized water and stir to dissolve them; wherein the initiator is one of benzoyl peroxide and ammonium persulfate, and the mass concentration of the initiator is 1-3wt%.

4. The quick-drying two-component water-based paint according to claim 1, characterized in that: Calculated by mass percentage, the mass ratio of dibutyl maleate and polyacrylamide as a whole to acrylic acid, methyl methacrylate and butyl acrylate as a whole is 10-30%:70-90%.

5. The quick-drying two-component water-based paint according to claim 1, characterized in that: Calculated by mass percentage, the mass ratio of polyacrylamide to dibutyl maleate is 10-20%:80-90%.

6. The quick-drying two-component water-based paint according to claim 1, characterized in that: The preparation of the shell emulsion also includes adjusting the pH of the shell pre-emulsion system to 7.6-8.5 using sodium hydroxide.

7. The quick-drying two-component water-based paint according to claim 1, characterized in that: Modified dibutyl maleate is used to replace dibutyl maleate in the preparation method of water-based acrylic emulsion. The preparation steps of the modified polydibutyl maleate are as follows: First, dissolve butyl acrylate, dibutyl maleate and vinyl acetate in an appropriate amount of acetone in a mass ratio of (2.2-4.8):1:(3.1-6.5), react at 70°C for 5 hours and at 80°C for 1 hour under the initiation of benzoyl peroxide, then cool to 30°C, add 1-3% of the total system mass of chlorinated paraffin, and freeze-dry to obtain the product.

8. A quick-drying two-component water-based paint according to any one of claims 1 or 7, characterized in that: The modified polyacrylamide is used to replace the polyacrylamide in the preparation method of the aqueous acrylic emulsion. The preparation steps of the modified polyacrylamide are as follows: The precursor solution is obtained by mixing triethyl phosphate and methyl methacrylate under the initiation of benzoyl peroxide; Anionic polyacrylamide is dissolved in water, and formaldehyde aqueous solution is added to react to obtain a mixture, and a precursor solution is added to the mixture to react to obtain a reactant, which is washed with water and freeze-dried to obtain the reactant.

9. A quick-drying two-component water-based paint according to claim 8, characterized in that: Based on the triethyl phosphate, the volume fraction of the methyl methacrylate is 4-5 vol%, and the amount of the benzoyl peroxide is 1-2wt%.

10. A process for preparing the quick-drying two-component water-based paint according to any one of claims 1 to 9, characterized in that: The following steps are involved: Add pigment, filler and dispersant into the agitator, disperse at a speed of 1000-1500 rpm for 10-20 minutes until a fine color paste is formed, reduce the speed to 500-800 rpm, slowly add water-based acrylic emulsion into the color paste, stir at a speed of 300-500 rpm for 10-15 minutes, add defoamer and film-forming aid, stir at a speed of 300-500 rpm for 3-5 minutes to evenly disperse them in the system, obtain component A, filter and package for storage; Mix component A and component B, stir at 300-500 rpm for 3-5 minutes, and the mixed components will be the water-based paint to be sprayed.

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