Hydroxy Acrylic Resin Dispersion for Waterborne Paint, Preparation Method Thereof, and Waterborne Paint

Abstract

The present disclosure provides a hydroxyl acrylic resin dispersion for waterborne paints, a preparation method thereof, and a waterborne paint, belonging to the technical field of waterborne acrylic resins. The hydroxyl acrylic resin dispersion for waterborne paints includes: 2-3 parts by mass of styrene; 7-8 parts by mass of methyl methacrylate; 23-24 parts by mass of isobutyl methacrylate; 2-3 parts by mass of hydroxypropyl methacrylate; 7-8 parts by mass of hydroxyethyl methacrylate; 0.5-1 part by mass of acrylic acid; 0.1-0.5 part by mass of diacetone acrylamide; 0.5-1.5 parts by mass of ethylene glycol dimethacrylate; 2-3 parts by mass of tert-butyl peroxy (2-ethylhexanoate); 2-3 parts by mass of diethylene glycol methyl ether; 1-2 parts by mass of N,N-dimethylethanolamine; 45-55 parts by mass of deionized water. By using the dispersion in combination with an isocyanate crosslinking agent, the application effect of an oil-based paint can be achieved, and at the same time, it also has good water resistance and acid and alkali resistance.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of waterborne acrylic resins, and particularly relates to a hydroxyl acrylic resin dispersion for waterborne paints, a preparation method thereof, and a waterborne paint. Background Art

[0002] A large amount of VOC emissions exist during the production and use of oil-based paints, which cannot meet the requirements of environmental development. Therefore, it is necessary to develop other paints with low VOC emissions, such as waterborne paints.

[0003] As an important component of waterborne paints, the performance of waterborne resins ultimately determines the performance of waterborne paints. Compared with traditional solvent-based acrylic resins, waterborne acrylic resins rarely use or do not use organic solvents, and have the advantages of reducing VOC emissions, being green and environmentally friendly, etc. The waterborne industrial paints made from them also have the advantages of low VOC emissions, green and environmentally friendly during the production and use processes; at the same time, waterborne acrylic resins have excellent light, heat, and chemical stability, and weather resistance. Therefore, waterborne acrylic resins have become the main development direction of current acrylic resins.

[0004] The waterborne hydroxyl acrylic resin dispersion is the main raw material of waterborne paints, and its performance and stability play a crucial role in the popularization and use of waterborne paints. The waterborne hydroxyl acrylic resin dispersion needs to be used in combination with a waterborne polyisocyanate curing agent to prepare high-end waterborne paints, which can be applied to fields such as automobiles, rail trains, and industrial equipment. However, due to the high price of the water-dispersed isocyanate curing agent, it limits the further popularization of waterborne paints. Moreover, the current waterborne hydroxyl acrylic resin dispersions have problems such as insufficient stability, slow drying speed, poor water resistance, and poor acid and alkali resistance, resulting in common problems such as poor water resistance and poor solvent resistance in current waterborne paints or waterborne resins on the market, especially the phenomenon that the paint film turns white easily when encountering water. Summary of the Invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a hydroxyl acrylic resin dispersion for waterborne paints, a preparation method thereof, and a waterborne paint.

[0006] On the one hand, the present disclosure provides a hydroxyl acrylic resin dispersion for waterborne paints, and the raw materials of the hydroxyl acrylic resin dispersion for waterborne paints include the following components in parts by mass:

[0007] 2 - 3 parts by mass of styrene;

[0008] 7 - 8 parts by mass of methyl methacrylate;

[0009] 23 - 24 parts by mass of isobutyl methacrylate;

[0010] 2 - 3 parts by mass of hydroxypropyl methacrylate;

[0011] 7 - 8 parts by mass of hydroxyethyl methacrylate;

[0012] 0.5 - 1 part by mass of acrylic acid;

[0013] 0.1 - 0.5 part by mass of diacetone acrylamide;

[0014] 0.5 - 1.5 parts by mass of ethylene glycol dimethacrylate;

[0015] 2 - 3 parts by mass of tert - butyl peroxy(2 - ethylhexanoate);

[0016] 2 - 3 parts by mass of diethylene glycol methyl ether;

[0017] 1 - 2 parts by mass of N,N - dimethylethanolamine;

[0018] 45 - 55 parts by mass of deionized water.

[0019] On the other hand, the present disclosure provides a method for preparing the hydroxy acrylic resin dispersion for water - based paint described above. The method includes:

[0020] S110: Form a first monomer mixture of styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, the total content of tert - butyl peroxy(2 - ethylhexanoate), and diethylene glycol methyl ether;

[0021] S120: Form a second monomer mixture of styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, acrylic acid, diacetone acrylamide, ethylene glycol dimethacrylate, tert - butyl peroxy(2 - ethylhexanoate), and diethylene glycol methyl ether;

[0022] S130: First, add diethylene glycol methyl ether to the reactor and stir. Heat it to the first temperature under nitrogen protection, and dropwise add the first monomer mixture. After the addition is completed, continue to dropwise add the second monomer mixture. After the first heat - preservation reaction, cool it to the second temperature, dropwise add styrene. After the addition is completed, add diethylene glycol methyl ether for the second time. After the second heat - preservation reaction, cool it to the third temperature, add N,N - dimethylethanolamine. After the third heat - preservation reaction, add deionized water, heat it to the fourth temperature for the fourth heat - preservation reaction, and then cool it to room temperature to obtain the hydroxy acrylic resin dispersion.

[0023] Optionally, the addition amount of styrene is 55 - 57% of the total content of its raw materials;

[0024] The addition amount of methyl methacrylate is 69 - 71% of the total content of its raw materials;

[0025] The addition amount of isobutyl methacrylate is 69 - 71% of the total raw material content;

[0026] The addition amount of hydroxypropyl methacrylate is 82 - 84% of the total raw material content;

[0027] The addition amount of hydroxyethyl methacrylate is 65 - 67% of the total raw material content;

[0028] The addition amount of tert-butyl peroxy(2-ethylhexanoate) is 69 - 71% of the total raw material content;

[0029] The addition amount of diethylene glycol methyl ether is 14 - 16% of the total raw material content.

[0030] Optionally, the addition amount of styrene is 23 - 25% of the total raw material content;

[0031] The addition amount of methyl methacrylate is 29 - 31% of the total raw material content;

[0032] The addition amount of isobutyl methacrylate is 29 - 31% of the total raw material content;

[0033] The addition amount of hydroxypropyl methacrylate is 16 - 18% of the total raw material content;

[0034] The addition amount of hydroxyethyl methacrylate is 33 - 35% of the total raw material content;

[0035] The addition amount of acrylic acid is 100% of the total raw material content;

[0036] The addition amount of diacetone acrylamide is 100% of the total raw material content;

[0037] The addition amount of ethylene glycol dimethacrylate is 100% of the total raw material content;

[0038] The addition amount of tert-butyl peroxy(2-ethylhexanoate) is 29 - 31% of the total raw material content;

[0039] The addition amount of diethylene glycol methyl ether is 6 - 8% of the total raw material content.

[0040] Optionally, the content of diethylene glycol methyl ether added for the first time is 75 - 77% of the total raw material content;

[0041] The addition amount of styrene is 18 - 22% of the total raw material content;

[0042] The content of diethylene glycol methyl ether added for the second time is 1 - 3% of the total raw material content;

[0043] The addition amount of the N,N-dimethylethanolamine is 100% of the total content of its raw materials.

[0044] Optionally, the first temperature is 130 - 140 °C, and the time for the first heat preservation reaction is 0.3 - 1 hour; and / or,

[0045] the second temperature is 110 - 125 °C, and the time for the second heat preservation reaction is 1 - 2 hours; and / or,

[0046] the third temperature is 70 - 90 °C, and the time for the third heat preservation reaction is 0.2 - 1 hour; and / or,

[0047] the fourth temperature is 50 - 70 °C, and the time for the fourth heat preservation reaction is 0.2 - 1 hour.

[0048] Optionally, the dropping time for dropping the first monomer mixture is controlled within 3 - 4 hours.

[0049] Optionally, the dropping of the second monomer mixture is controlled within 1 - 2 hours.

[0050] Optionally, the dropping time for dropping styrene is controlled within 0.2 - 0.5 hours.

[0051] On the other hand of the present disclosure, an aqueous paint is proposed, and the aqueous paint includes an isocyanate crosslinking agent and the hydroxyl acrylic resin dispersion described above.

[0052] The present disclosure provides a hydroxyl acrylic resin dispersion for aqueous paint, a preparation method thereof, and an aqueous paint. The raw materials of the hydroxyl acrylic resin dispersion for aqueous paint include the following components in parts by mass: 2 - 3 parts by mass of styrene; 7 - 8 parts by mass of methyl methacrylate; 23 - 24 parts by mass of isobutyl methacrylate; 2 - 3 parts by mass of hydroxypropyl methacrylate; 7 - 8 parts by mass of hydroxyethyl methacrylate; 0.5 - 1 part by mass of acrylic acid; 0.1 - 0.5 part by mass of diacetone acrylamide; 0.5 - 1.5 parts by mass of ethylene glycol dimethacrylate; 2 - 3 parts by mass of tert-butyl peroxy (2-ethylhexanoate); 2 - 3 parts by mass of diethylene glycol methyl ether; 1 - 2 parts by mass of N,N-dimethylethanolamine; 45 - 55 parts by mass of deionized water. By optimizing each component and its content, a hydroxyl acrylic resin dispersion for aqueous paint with excellent water resistance and acid and alkali resistance is formed. When it is used in an aqueous paint, by using this dispersion in combination with an isocyanate crosslinking agent, the application effect of an oil-based paint can be achieved, and at the same time, it also has good water resistance and acid and alkali resistance, without the need for water treatment of the isocyanate crosslinking agent, reducing costs. Description of the Drawings

[0053] Figure 1It is a flowchart of the preparation method of the hydroxyl acrylic resin dispersion for waterborne paint in the specific implementation manner of the present disclosure. Specific implementation manner

[0054] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below with reference to the accompanying drawings and specific implementation manners. It should be understood that the specific embodiments described herein are only used to explain the present disclosure, which are a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0055] On the one hand, the present disclosure provides a hydroxyl acrylic resin dispersion for waterborne paint. The raw materials of the hydroxyl acrylic resin dispersion for waterborne paint include the following components in parts by mass: 2 - 3 parts by mass of styrene; 7 - 8 parts by mass of methyl methacrylate; 23 - 24 parts by mass of isobutyl methacrylate; 2 - 3 parts by mass of hydroxypropyl methacrylate; 7 - 8 parts by mass of hydroxyethyl methacrylate; 0.5 - 1 part by mass of acrylic acid; 0.1 - 0.5 part by mass of diacetone acrylamide; 0.5 - 1.5 parts by mass of ethylene glycol dimethacrylate; 2 - 3 parts by mass of tert-butyl peroxy(2-ethylhexanoate); 2 - 3 parts by mass of diethylene glycol methyl ether; 1 - 2 parts by mass of N,N-dimethylethanolamine; 45 - 55 parts by mass of deionized water.

[0056] Among them, styrene is used as a vinyl monomer; methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, and acrylic acid are acrylate and propylene monomers, which constitute the basic units of the resin, provide crosslinking points and the basis for chemical reactions for the curing of two-component waterborne paint, and improve the dispersibility of the resin at the same time.

[0057] Secondly, diethylene glycol methyl ether is used as a hydrophilic solvent to adjust the viscosity and construction performance of the resin. N,N-dimethylethanolamine is used as a neutralizing agent to adjust the pH value of the resin and improve the resin stability. Tert-butyl peroxy(2-ethylhexanoate) is a free radical initiator used for the polymerization reaction of vinyl, acrylate, and propylene monomers, and can effectively initiate the polymerization of these monomers.

[0058] Furthermore, diacetone acrylamide has N-substituted amide and methyl ketone, and it is very easy to copolymerize with other ethylene and monomers to introduce a ketone carbonyl group into the polymer, prompting it to participate in reactions such as cross-linking and grafting, enhancing adhesiveness, and improving acid-base and chemical corrosion resistance. At the same time, ethylene glycol dimethacrylate increases the hardness of the paint film through participating in copolymerization polymerization, and at the same time improves water resistance, heat resistance, weather resistance, solvent resistance and friction resistance. That is to say, diacetone acrylamide and ethylene glycol dimethacrylate are key components for water resistance and acid-base resistance. During the synthesis process of the system, these components undergo a grafting reaction with styrene and acrylate monomers to form a three-dimensional network cross-linked structure, increasing the cross-linking density, and further improving the water resistance, acid-base resistance and other chemical resistance properties. In addition, it should be noted that the reactivity ratio of ethylene glycol dimethacrylate relative to other monomers shows a relatively small value. For example, compared with styrene, its copolymerization ability is relatively weak. Therefore, in the present invention, by adding diacetone acrylamide, since the diacetone acrylamide component is very easy to copolymerize with various monomers to introduce a ketone carbonyl group into the polymer, it prompts ethylene glycol dimethacrylate to participate in copolymerization. However, since diacetone acrylamide can also homopolymerize, reducing the mass fraction of diacetone acrylamide prompts it to copolymerize. That is to say, the added diacetone acrylamide component in the present invention can not only copolymerize with other monomers by itself, but also cooperate with ethylene glycol dimethacrylate to prompt ethylene glycol dimethacrylate to copolymerize with other monomers to form a three-dimensional network cross-linked structure, increasing the cross-linking density, and further improving the water resistance, solvent resistance and other properties of the paint film.

[0059] At the same time, the polyhydroxy structure in the system further increases the cross-linking density and improves the water resistance, acid-base resistance and other chemical resistance properties of the paint film when reacting with the isocyanate cross-linking agent later.

[0060] In some preferred embodiments, the total content of the styrene raw material can be preferably 2 parts by mass, 2.5 parts by mass, 3 parts by mass, etc.

[0061] In some other preferred embodiments, the total content of the methyl methacrylate raw material can be preferably 7 parts by mass, 7.5 parts by mass, 8 parts by mass, etc.

[0062] In some other preferred embodiments, the total content of the isobutyl methacrylate raw material can be preferably 23 parts by mass, 23.5 parts by mass, 24 parts by mass, etc.

[0063] In some other preferred embodiments, the total content of the hydroxypropyl methacrylate raw material can be preferably 2 parts by mass, 2.5 parts by mass, 3 parts by mass, etc.

[0064] In some other preferred embodiments, the total content of the hydroxyethyl methacrylate raw material can be preferably 7 parts by mass, 7.5 parts by mass, 8 parts by mass, etc.

[0065] In some other preferred embodiments, the total content of the acrylic raw material may preferably be 0.5 parts by mass, 0.7 parts by mass, 1 part by mass, etc.

[0066] In some other preferred embodiments, the total content of the diacetone acrylamide raw material may preferably be 0.1 parts by mass, 0.3 parts by mass, 0.5 parts by mass, etc.

[0067] In some other preferred embodiments, the total content of the ethylene glycol dimethacrylate raw material may preferably be 0.5 parts by mass, 0.8 parts by mass, 1 part by mass, 1.5 parts by mass, etc.

[0068] In some other preferred embodiments, the total content of the tert-butyl peroxy (2-ethylhexanoate) raw material may preferably be 2 parts by mass, 2.5 parts by mass, 3 parts by mass, etc.

[0069] In some other preferred embodiments, the total content of the diethylene glycol methyl ether raw material may preferably be 2 parts by mass, 2.5 parts by mass, 3 parts by mass, etc.

[0070] In some other preferred embodiments, the total content of the N,N-dimethylethanolamine raw material may preferably be 1 part by mass, 1.5 parts by mass, 2 parts by mass, etc.

[0071] In some other preferred embodiments, the total content of the deionized water is preferably 1 part by mass, 1.5 parts by mass, 2 parts by mass, etc.

[0072] In this embodiment, by optimizing the components and their contents, based on the interaction of the components, a hydroxyl acrylic resin dispersion for waterborne paint with excellent water resistance and acid and alkali resistance is formed. When it is used in waterborne paint, by using this dispersion in combination with an isocyanate crosslinking agent, the application effect of oil-based paint can be achieved, and at the same time, it also has good water resistance and acid and alkali resistance properties. In particular, the phenomenon of the paint film turning white is not likely to occur when exposed to water, that is, there is no whitening phenomenon after being soaked in water, and at the same time, there is no need to perform water treatment on the isocyanate crosslinking agent, reducing costs.

[0073] As shown in FIG. 1, on the other hand, the present disclosure provides a preparation method S100 of a hydroxyl acrylic resin dispersion for waterborne paint, which specifically includes the following steps S110 to S130:

[0074] S110. Form a first monomer mixture of styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, the total content of tert-butyl peroxy (2-ethylhexanoate), and diethylene glycol methyl ether.

[0075] In step S110, the addition amount of styrene is 55-57% of the total content of its raw materials, for example, 55%, 56%, 57%, etc., and specifically may preferably be 1.1-1.6 parts by mass.

[0076] In step S110, the addition amount of methyl methacrylate is 69-71% of the total raw material content. For example, 69%, 70%, 71%, etc., and specifically, 4.9-5.6 parts by mass, etc. can be preferably used.

[0077] In step S110, the addition amount of isobutyl methacrylate is 69-71% of the total raw material content. For example, 69%, 70%, 71%, etc., and specifically, 15.9-17 parts by mass, etc. can be preferably used.

[0078] In step S110, the addition amount of hydroxypropyl methacrylate is 82-84% of the total raw material content. For example, 82%, 83%, 84%, etc., and specifically, 1.6-2.5 parts by mass, etc. can be preferably used.

[0079] In step S110, the addition amount of hydroxyethyl methacrylate is 65-67% of the total raw material content. For example, 65%, 66%, 67%, etc., and specifically, 4.5-5.3 parts by mass, etc. can be preferably used.

[0080] In step S110, the addition amount of tert-butyl peroxy(2-ethylhexanoate) is 69-71% of the total raw material content. For example, 69%, 70%, 71%, etc., and specifically, 1.4-2.1 parts by mass, etc. can be preferably used.

[0081] In step S110, the addition amount of diethylene glycol methyl ether is 14-16% of the total raw material content. For example, 14%, 15%, 16%, etc., and specifically, 0.28-0.48 parts by mass, etc. can be preferably used.

[0082] It should be understood that the addition amounts of the above components are part of the total amount of their corresponding raw materials. That is to say, according to the total content of each raw material in the formula, a part of it is first mixed to form the first monomer mixture, and the remaining part is added in other steps.

[0083] S120. Styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, acrylic acid, diacetone acrylamide and ethylene glycol dimethacrylate, tert-butyl peroxy(2-ethylhexanoate), and diethylene glycol methyl ether are used to form a second monomer mixture.

[0084] In step S120, the addition amount of styrene is 23-25% of the total raw material content. For example, 23%, 24%, 25%, etc., and specifically, 0.46-0.75 parts by mass can be preferably used.

[0085] In step S120, the addition amount of methyl methacrylate is 29-31% of the total raw material content. For example, 29%, 30%, 31%, etc., that is, the remaining methyl methacrylate in the formula is added to step S120.

[0086] In step S120, the addition amount of isobutyl methacrylate is 29 - 31% of the total raw material content, for example, 29%, 30%, 31%, etc. That is, the remaining isobutyl methacrylate in the formulation is added to step S120.

[0087] In step S120, the addition amount of hydroxypropyl methacrylate is 16 - 18% of the total raw material content, for example, 16%, 17%, 18%, etc. That is, the remaining hydroxypropyl methacrylate in the formulation is added to step S120.

[0088] In step S120, the addition amount of hydroxyethyl methacrylate is 33 - 35% of the total raw material content, for example, 33%, 34%, 35%, etc. That is, the remaining hydroxyethyl methacrylate in the formulation is added to step S120.

[0089] In step S120, the addition amount of acrylic acid is 100% of the total raw material content. That is, all of the acrylic acid is added to step S120, and preferably 0.5 - 1 part by mass.

[0090] In step S120, the addition amount of diacetone acrylamide is 100% of the total raw material content. That is, all of the diacetone acrylamide is added to step S120, and preferably 0.1 - 0.5 part by mass.

[0091] In step S120, the addition amount of ethylene glycol dimethacrylate is 100% of the total raw material content. That is, all of the ethylene glycol dimethacrylate is added to step S120, and preferably 0.5 - 1.5 part by mass.

[0092] In step S120, the addition amount of tert-butyl peroxy (2-ethylhexanoate) is 29 - 31% of the total raw material content, for example, 29%, 30%, 31%, and specifically preferably 0.6 - 0.9 part by mass.

[0093] In step S120, the addition amount of diethylene glycol methyl ether is 6 - 8% of the total raw material content, for example, 6%, 7%, 8%, and specifically preferably 0.12 - 0.24 part by mass.

[0094] S130. First, add diethylene glycol methyl ether into the reactor and stir. Heat it to the first temperature under the protection of nitrogen, and then dropwise add the first monomer mixture. After the dropping is completed, continue to dropwise add the second monomer mixture. After the first heat preservation reaction, cool down to the second temperature, and then dropwise add styrene. After the dropping is completed, add the remaining diethylene glycol methyl ether for the second time. After the second heat preservation reaction, cool down to the third temperature, add N,N-dimethylethanolamine. After the third heat preservation reaction, add deionized water, heat up to the fourth temperature for the fourth heat preservation reaction, and then cool down to room temperature to obtain the hydroxyl acrylic resin dispersion.

[0095] In step S130, the content of the diethylene glycol methyl ether added for the first time is 75 - 77% of the total raw material content, for example, 75%, 76%, 77%, and specifically, 1.5 - 2.3 parts by mass can be preferably selected. The content of the diethylene glycol methyl ether added for the second time is 1 - 3% of the total raw material content, for example, 1%, 2%, 3%, that is, all the remaining diethylene glycol methyl ether in the formula is added to step S130.

[0096] In step S130, the addition amount of styrene is 18 - 22% of the total raw material content, for example, 18%, 20%, 22%, that is, all the remaining styrene in the formula is added to step S130.

[0097] In step S130, the addition amount of N,N-dimethylethanolamine is 100% of the total raw material content, that is, all the N,N-dimethylethanolamine in the formula is added to step S130, and specifically, 1 - 2 parts by mass can be preferably selected.

[0098] Furthermore, in step 130, the first temperature is 130 - 140 °C, for example, 130 °C, 135 °C, 140 °C, etc., and the time of the first heat preservation reaction is 0.3 - 1 hour, for example, 0.3 hour, 0.5 hour, 1 hour, etc.

[0099] In step 130, the second temperature is 110 - 125 °C, for example, 110 °C, 115 °C, 120 °C, 125 °C, etc., and the time of the second heat preservation reaction is 1 - 2 hours, for example, 1 hour, 1.5 hours, 2 hours, etc.

[0100] In this embodiment, by controlling the reaction temperature (including the first temperature and the second temperature) within the above range, it helps to shorten the half-life of the initiator (tert-butyl peroxy (2-ethylhexanoate)), thereby improving the reaction efficiency. And the above reaction time range exactly matches the half-life of the initiator. If the reaction time is too long, it will waste production time; if the reaction time is too short, the monomers will not fully react. Therefore, controlling the second temperature and the first temperature within the above range helps to reduce the reaction time and improve the efficiency.

[0101] In step 130, the third temperature is 70 - 90 °C, for example, 70 °C, 80 °C, 90 °C, etc., and the time for the third heat preservation reaction is 0.2 - 1 hour, for example, 0.2 hour, 0.5 hour, 1 hour, etc.

[0102] In step 130, the fourth temperature is 50 - 70 °C, for example, 50 °C, 60 °C, 70 °C, etc., and the time for the fourth heat preservation reaction is 0.2 - 1 hour, for example, 0.2 hour, 0.5 hour, 1 hour, etc.

[0103] Furthermore, in step S130, the dropping time of the first monomer mixture is controlled within 3 - 4 hours, for example, 3 hours, 3.5 hours, 4 hours, etc.

[0104] In step S130, the dropping of the second monomer mixture is controlled within 1 - 2 hours, for example, 1 hour, 1.5 hours, 2 hours, etc.

[0105] In step S130, the dropping time of styrene is controlled within 0.2 - 0.5 hour, for example, 0.2 hour, 0.3 hour, 0.5 hour, etc.

[0106] In the preparation process provided in this embodiment, by forming the monomer mixture step by step and adding the monomer mixture into the reactor step by step during the reaction to react at different temperatures, it can promote the full grafting reaction between diacetone acrylamide and ethylene glycol dimethacrylate. Through the copolymerization of the two with other monomers, a three-dimensional network cross-linked structure is formed, effectively improving the cross-linking density. Compared with the dispersion polymerized by the conventional one-step method, it has good water resistance and acid and alkali resistance. Moreover, this preparation method is easy to implement in practical applications, has been verified in different reaction kettles, can quickly achieve mass production, and the prepared dispersion has good water resistance and acid and alkali resistance. When used in combination with an isocyanate cross-linking agent, the isocyanate cross-linking agent does not require other water resistance treatments.

[0107] On the other hand, the present disclosure proposes an aqueous paint, which includes an isocyanate cross-linking agent and the hydroxyl acrylic resin dispersion given above.

[0108] When the hydroxyl acrylic resin dispersion proposed in this embodiment is used in combination with an isocyanate cross-linking agent, the application effect of an oil-based paint can be achieved, and it has very good water resistance and acid and alkali resistance.

[0109] It should be noted that when the hydroxyl acrylic resin dispersion is used in combination with an isocyanate cross-linking agent, the mass ratio range of the two is preferably 100:(20 - 30).

[0110] In some preferred embodiments, the mass ratio of the hydroxy acrylic resin dispersion to the isocyanate crosslinking agent is preferably 100:20, 100:25, 100:30, etc.

[0111] The preparation method and components of the hydroxy acrylic resin dispersion will be further described below in conjunction with specific embodiments:

[0112] Example 1

[0113] In this example, the raw material composition of the hydroxy acrylic resin dispersion is as follows by weight: Styrene 2.3 parts by mass

[0114] Methyl methacrylate 7.1 parts by mass

[0115] Isobutyl methacrylate 23.8 parts by mass

[0116] Hydroxypropyl methacrylate 2.5 parts by mass

[0117] Hydroxyethyl methacrylate 7.8 parts by mass

[0118] Acrylic acid 0.9 parts by mass

[0119] Diacetone acrylamide 0.2 parts by mass

[0120] Ethylene glycol dimethacrylate 1.0 parts by mass

[0121] tert-Butyl peroxy (2-ethylhexanoate) 2.0 parts by mass

[0122] N,N-Dimethylethanolamine 1.1 parts by mass

[0123] Diethylene glycol methyl ether 2.1 parts by mass

[0124] Deionized water 49.2 parts by mass

[0125] Total 100 parts by mass.

[0126] Furthermore, the preparation method of the above-mentioned hydroxy acrylic resin dispersion includes the following steps:

[0127] S1. Take 55% of the total amount of styrene in the above formula, i.e., 1.265 parts; 70% of the total amount of methyl methacrylate, i.e., 4.97 parts; 70% of the total amount of isobutyl methacrylate, i.e., 16.66 parts; 84% of the total amount of hydroxypropyl methacrylate, i.e., 2.1 parts; 66% of the total amount of hydroxyethyl methacrylate, 5.148 parts; 70% of the total amount of tert-butyl peroxy (2-ethylhexanoate), i.e., 1.4 parts; 15% of the total amount of diethylene glycol methyl ether, i.e., 0.315 parts, to form a first monomer mixture;

[0128] S2. Take 23% of the total amount of styrene in the above formula, which is 0.529 parts; the remaining methyl methacrylate; the remaining isobutyl methacrylate; the remaining hydroxypropyl methacrylate, the remaining hydroxyethyl methacrylate, all acrylic acid, diacetone acrylamide and ethylene glycol dimethacrylate, the remaining tert-butyl peroxy(2-ethylhexanoate), 7% of the total amount of diethylene glycol methyl ether, which is 0.147 parts, to form a second monomer mixture;

[0129] S3. Take 77% of the total amount of diethylene glycol methyl ether, which is 1.617 parts of diethylene glycol methyl ether, and add it to a reactor with nitrogen protection, heating, stirring and condensation reflux. Start stirring, heat to 132 °C under nitrogen protection, and slowly dropwise add the first monomer mixture. The dropping time is controlled within 3.2 hours. After the dropping is completed, continue to dropwise add the second monomer mixture. The dropping time is controlled within 1.5 hours. After holding the reaction for 1 hour, cool down to 115 °C, dropwise add the remaining styrene. The dropping time is controlled within 0.25 hours. After the dropping is completed, add the remaining diethylene glycol methyl ether, hold for 1 hour, cool down to 75 °C, add N,N-dimethylethanolamine, hold for 0.5 hours, increase the stirring speed, add deionized water, heat up to 60 °C, hold for 0.5 hours, cool down to room temperature, and discharge and filter.

[0130] Furthermore, the hydroxyl acrylic resin dispersion obtained in Example 1 is used in combination with an isocyanate crosslinking agent. The test results of the water resistance of the obtained paint film are shown in Table 1. After soaking in hot water at 40 °C for 10 days and soaking in hot water at 90 °C for 40 minutes, there is no whitening phenomenon on the paint film. After soaking in 5% sulfuric acid solution, 5% sodium hydroxide solution and industrial alcohol, the number of scrubbing resistance times is still greater than 600 times. This shows that the paint film obtained by using the dispersion obtained in this example in combination with the isocyanate crosslinking agent has good water resistance and acid and alkali resistance.

[0131] Example 2

[0132] In this example, the raw material composition of the hydroxyl acrylic resin dispersion is as follows by weight: styrene 3 parts by mass

[0133] methyl methacrylate 8 parts by mass

[0134] isobutyl methacrylate 24 parts by mass

[0135] hydroxypropyl methacrylate 2.5 parts by mass

[0136] hydroxyethyl methacrylate 7 parts by mass

[0137] acrylic acid 0.5 parts by mass

[0138] diacetone acrylamide 0.5 parts by mass

[0139] ethylene glycol dimethacrylate 1.5 parts by mass

[0140] 3.0 parts by mass of tert-butyl peroxy(2-ethylhexanoate)

[0141] 2 parts by mass of N,N-dimethylethanolamine

[0142] 3 parts by mass of diethylene glycol methyl ether

[0143] 45 parts by mass of deionized water

[0144] Total: 100 parts by mass.

[0145] Furthermore, the preparation method of the above hydroxy acrylic resin dispersion comprises the following steps:

[0146] S1. Take 57% of the total amount of styrene in the above formula, i.e., 1.71 parts; 69% of the total amount of methyl methacrylate, i.e., 5.52 parts; 69% of the total amount of isobutyl methacrylate, i.e., 16.56 parts; 82% of the total amount of hydroxypropyl methacrylate, i.e., 2.05 parts; 65% of the total amount of hydroxyethyl methacrylate, 4.55 parts; 69% of the total amount of tert-butyl peroxy(2-ethylhexanoate), i.e., 2.07 parts; 14% of the total amount of diethylene glycol methyl ether, i.e., 0.42 parts, to form a first monomer mixture.

[0147] S2. Take 25% of the total amount of styrene in the above formula, i.e., 0.75 parts; the remaining methyl methacrylate; the remaining isobutyl methacrylate; the remaining hydroxypropyl methacrylate, the remaining hydroxyethyl methacrylate, all acrylic acid, diacetone acrylamide and ethylene glycol dimethacrylate, the remaining tert-butyl peroxy(2-ethylhexanoate), 8% of the total amount of diethylene glycol methyl ether, i.e., 0.24 parts, to form a second monomer mixture.

[0148] S3. Add 2.34 parts of diethylene glycol methyl ether, which is 78% of the total amount of diethylene glycol methyl ether, to a reactor with nitrogen protection, heating, stirring and condensation reflux. Start stirring, heat to 132 °C under nitrogen protection, and slowly dropwise add the first monomer mixture. The dropping time is controlled within 3.2 hours. After the dropping is completed, continue to dropwise add the second monomer mixture. The dropping time is controlled within 1.5 hours. After holding the reaction for 1 hour, cool down to 115 °C, dropwise add the remaining styrene. The dropping time is controlled within 0.25 hours. After the dropping is completed, add the remaining diethylene glycol methyl ether, hold for 1 hour, cool down to 75 °C, add N,N-dimethylethanolamine, hold for 0.5 hours, increase the stirring speed, add deionized water, heat up to 60 °C, hold for 0.5 hours, cool down to room temperature, and discharge and filter.

[0149] Furthermore, the hydroxy acrylic resin dispersion obtained in Example 2 is used in combination with an isocyanate crosslinking agent. The water resistance test results of the obtained paint film are shown in Table 1. It can be seen that changing the contents of each component has a small influence on the paint film, and all have good water resistance and acid and alkali resistance.

[0150] Example 3

[0151] In this example, the raw material composition of the hydroxyl acrylic resin dispersion is the same as that of Example 1 by weight ratio.

[0152] Furthermore, the preparation method of the above-mentioned hydroxyl acrylic resin dispersion includes the following steps:

[0153] S1. Take 57% of the total amount of styrene in the above formula, that is, 1.71 parts; 69% of the total amount of methyl methacrylate, that is, 5.52 parts; 69% of the total amount of isobutyl methacrylate, that is, 16.56 parts; 82% of the total amount of hydroxypropyl methacrylate, that is, 2.05 parts; 65% of the total amount of hydroxyethyl methacrylate, 4.55 parts; 69% of the total amount of tert-butyl peroxy(2-ethylhexanoate), that is, 2.07 parts; 14% of the total amount of diethylene glycol methyl ether, that is, 0.42 parts, to form a first monomer mixture.

[0154] S2. Take 25% of the total amount of styrene in the above formula, that is, 0.75 parts; the remaining methyl methacrylate; the remaining isobutyl methacrylate; the remaining hydroxypropyl methacrylate, the remaining hydroxyethyl methacrylate, all acrylic acid, diacetone acrylamide and ethylene glycol dimethacrylate, the remaining tert-butyl peroxy(2-ethylhexanoate), 8% of the total amount of diethylene glycol methyl ether, that is, 0.24 parts, to form a second monomer mixture.

[0155] S3. Take 78% of the total amount of diethylene glycol methyl ether, that is, 2.34 parts of diethylene glycol methyl ether and add it to a reactor with nitrogen protection, heating, stirring and condensation reflux. Start stirring, heat to 140 °C under nitrogen protection, slowly dropwise add the first monomer mixture, control the dropping time within 3.6 hours. After the dropping is completed, continue to dropwise add the second monomer mixture, control the dropping time within 1.8 hours. After holding the reaction for 1.5 hours, cool down to 120 °C, dropwise add the remaining styrene, control the dropping time within 0.45 hours. After the dropping is completed, add the remaining diethylene glycol methyl ether, hold for 1.5 hours, cool down to 85 °C, add N,N-dimethylethanolamine, hold for 1 hour, increase the stirring speed, add deionized water, heat up to 70 °C, hold for 1 hour, cool down to room temperature, and discharge and filter.

[0156] Furthermore, the hydroxyl acrylic resin dispersion obtained in this Example 3 is used in combination with an isocyanate crosslinking agent. The water resistance test results of the obtained paint film are shown in Table 1. It can be seen that changing the holding temperature, time and dropping time in the preparation process has little influence on the results of the paint film, and all have good water resistance and acid and alkali resistance.

[0157] Comparative Example 1

[0158] Same as Example 1, except that there is no diacetone acrylamide and ethylene glycol dimethacrylate in the raw materials, and the raw material composition of the hydroxy acrylic resin dispersion is as follows by weight:

[0159] Styrene: 5 parts by mass

[0160] Methyl methacrylate: 8 parts by mass

[0161] Isobutyl methacrylate: 24 parts by mass

[0162] Hydroxypropyl methacrylate: 2.5 parts by mass

[0163] Hydroxyethyl methacrylate: 7 parts by mass

[0164] Acrylic acid: 0.5 parts by mass

[0165] tert-Butyl peroxy (2-ethylhexanoate): 3.0 parts by mass

[0166] N,N-Dimethylethanolamine: 2 parts by mass

[0167] Diethylene glycol methyl ether: 3 parts by mass

[0168] Deionized water: 45 parts by mass

[0169] Total: 100 parts by mass.

[0170] Furthermore, the preparation method of the above-mentioned hydroxy acrylic resin dispersion includes the following steps:

[0171] S1. Take 57% of the total amount of styrene in the above formula, i.e., 1.71 parts; 69% of the total amount of methyl methacrylate, i.e., 5.52 parts; 69% of the total amount of isobutyl methacrylate, i.e., 16.56 parts; 82% of the total amount of hydroxypropyl methacrylate, i.e., 2.05 parts; 65% of the total amount of hydroxyethyl methacrylate, 4.55 parts; 69% of the total amount of tert-butyl peroxy (2-ethylhexanoate), i.e., 2.07 parts; 14% of the total amount of diethylene glycol methyl ether, i.e., 0.42 parts, to form the first monomer mixture;

[0172] S2. Take 25% of the total amount of styrene in the above formula, i.e., 0.75 parts; the remaining methyl methacrylate; the remaining isobutyl methacrylate; the remaining hydroxypropyl methacrylate, the remaining hydroxyethyl methacrylate, all of the acrylic acid, the remaining tert-butyl peroxy (2-ethylhexanoate), 8% of the total amount of diethylene glycol methyl ether, i.e., 0.24 parts, to form the second monomer mixture;

[0173] S3. Take 78% of the total amount of diethylene glycol methyl ether, i.e., 2.34 parts of diethylene glycol methyl ether, and add it to a reactor equipped with nitrogen protection, heating, stirring, and condensation reflux. Start stirring and heat to 132 °C under nitrogen protection. Slowly dropwise add the first monomer mixture, with the dropping time controlled at 3.2 hours. After the dropping is completed, continue to dropwise add the second monomer mixture, with the dropping time controlled at 1.5 hours. After holding the reaction for 1 hour, cool down to 115 °C, dropwise add the remaining styrene, with the dropping time controlled at 0.25 hours. After the dropping is completed, add the remaining diethylene glycol methyl ether, hold for 1 hour, cool down to 75 °C, add N,N-dimethylethanolamine, hold for 0.5 hours, increase the stirring speed, add deionized water, heat up to 60 °C, hold for 0.5 hours, cool down to room temperature, and discharge and filter.

[0174] The hydroxyl acrylic resin dispersion obtained in this Comparative Example 1 was used in combination with an isocyanate crosslinking agent. The water resistance test results of the obtained paint film are shown in Table 2. It can be seen that when diacetone acrylamide and ethylene glycol dimethacrylate are not added, the obtained paint film shows a whitening phenomenon and does not have good water resistance, acid resistance, and alkali resistance.

[0175] Comparative Example 2

[0176] Same as Example 1, except that there is no diacetone acrylamide in the raw materials, and the raw material composition of the hydroxyl acrylic resin dispersion is as follows by weight:

[0177] Styrene 2.5 parts by mass

[0178] Methyl methacrylate 7.1 parts by mass

[0179] Isobutyl methacrylate 23.8 parts by mass

[0180] Hydroxypropyl methacrylate 2.5 parts by mass

[0181] Hydroxyethyl methacrylate 7.8 parts by mass

[0182] Acrylic acid 0.9 parts by mass

[0183] Ethylene glycol dimethacrylate 1.0 parts by mass

[0184] tert-Butyl peroxy (2-ethylhexanoate) 2.0 parts by mass

[0185] N,N-Dimethylethanolamine 1.1 parts by mass

[0186] Diethylene glycol methyl ether 2.1 parts by mass

[0187] Deionized water 49.2 parts by mass

[0188] Total 100 parts by mass.

[0189] Further, the preparation method of the above hydroxy acrylic resin dispersion is the same as that in Example 1.

[0190] The hydroxy acrylic resin dispersion obtained in this Comparative Example 2 was used in combination with an isocyanate crosslinking agent, and the water resistance test results of the obtained paint film are shown in Table 2. It can be seen that when diacetone acrylamide is not added, the obtained paint film shows a slight whitening phenomenon and does not have good water resistance, acid resistance and alkali resistance.

[0191] Comparative Example 3

[0192] Same as Example 1, except that ethylene glycol dimethacrylate is not present in the raw materials, and the raw material composition of the hydroxy acrylic resin dispersion is as follows by weight:

[0193] Styrene 3.5 parts by mass

[0194] Methyl methacrylate 7.1 parts by mass

[0195] Isobutyl methacrylate 23.8 parts by mass

[0196] Hydroxypropyl methacrylate 2.5 parts by mass

[0197] Hydroxyethyl methacrylate 7.8 parts by mass

[0198] Acrylic acid 0.9 parts by mass

[0199] Diacetone acrylamide 0.2 parts by mass

[0200] tert-Butyl peroxy (2-ethylhexanoate) 2.0 parts by mass

[0201] N,N-Dimethylethanolamine 1.1 parts by mass

[0202] Diethylene glycol methyl ether 2.1 parts by mass

[0203] Deionized water 49.2 parts by mass

[0204] Total 100 parts by mass.

[0205] Further, the preparation method of the above hydroxy acrylic resin dispersion is the same as that in Example 1.

[0206] The hydroxy acrylic resin dispersion obtained in this Comparative Example 3 was used in combination with an isocyanate crosslinking agent, and the water resistance test results of the obtained paint film are shown in Table 2. It can be seen that when ethylene glycol dimethacrylate is not added, the obtained paint film shows a slight whitening phenomenon and does not have good water resistance, acid resistance and alkali resistance.

[0207] Comparative Example 4

[0208] Same as Example 1, except that the mass fraction of diacetone acrylamide is 1, and the raw material composition of the hydroxy acrylic resin dispersion is as follows by weight:

[0209] Styrene 1.5 parts by mass

[0210] Methyl methacrylate 7.1 parts by mass

[0211] Isobutyl methacrylate 23.8 parts by mass

[0212] Hydroxypropyl methacrylate 2.5 parts by mass

[0213] Hydroxyethyl methacrylate 7.8 parts by mass

[0214] Acrylic acid 0.9 parts by mass

[0215] Diacetone acrylamide 1.0 part by mass

[0216] Ethylene glycol dimethacrylate 1.0 part by mass

[0217] tert-Butyl peroxy (2-ethylhexanoate) 2.0 parts by mass

[0218] N,N-Dimethylethanolamine 1.1 parts by mass

[0219] Diethylene glycol methyl ether 2.1 parts by mass

[0220] Deionized water 49.2 parts by mass

[0221] Total 100 parts by mass.

[0222] Furthermore, the preparation method of the above hydroxy acrylic resin dispersion is the same as that of Example 1.

[0223] The hydroxy acrylic resin dispersion obtained in this Comparative Example 4 is used in combination with an isocyanate crosslinking agent, and the water resistance test results of the obtained paint film are shown in Table 2. It can be seen that when diethylene glycol dimethacrylate and diacetone acrylamide are contained, but the content of diacetone acrylamide is relatively high, the obtained paint film shows a slight whitening phenomenon and does not have good water resistance, acid resistance and alkali resistance.

[0224] In summary, the hydroxy acrylic resin dispersions obtained in Comparative Examples 1 to 4 are used in combination with an isocyanate crosslinking agent, and the water resistance test results of the obtained paint films are shown in Table 2. It can be seen that when the raw materials do not contain diacetone acrylamide and / or diethylene glycol dimethacrylate, the paint film shows a whitening phenomenon after soaking, and the scrub resistance times are all unqualified, and it does not have good water resistance, acid resistance and alkali resistance.

[0225] Comparative Example 5

[0226] The raw material composition is the same as that of Example 1, except that a conventional one-step polymerization method is adopted, including:

[0227] A monomer mixture is formed by styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, tert-butyl peroxy(2-ethylhexanoate), acrylic acid, diacetone acrylamide, ethylene glycol dimethacrylate and diethylene glycol methyl ether. Then, it is kept at 140 °C for 3 h, cooled to 60 °C, neutralized with N,N-dimethylethanolamine, and finally deionized water is added for high-speed dispersion to obtain a dispersion.

[0228] The hydroxy acrylic resin dispersion obtained in Comparative Example 5 is used in combination with an isocyanate crosslinking agent. The water resistance test results of the obtained paint film are shown in Table 2. It can be seen that when the one-step polymerization method is used, the obtained paint film shows a slight whitening phenomenon and does not have good water resistance, acid resistance and alkali resistance. This shows that the conventional preparation method cannot meet the sufficient mixing of each component, and diacetone acrylamide and ethylene glycol dimethacrylate do not fully undergo grafting reactions, and a three-dimensional network crosslinked structure cannot be formed, thereby having an adverse effect on the water resistance, acid resistance and alkali resistance of the paint film.

[0229] Table 1 Water resistance test results of the paint films of each example

[0230]

[0231] Table 2 Water resistance test results of the paint films of each comparative example

[0232]

[0233] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present disclosure. However, the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A method for preparing a hydroxylated acrylic resin dispersion for water-based paint, characterized in that: The method comprises: S110, forming a first monomer mixture by combining styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, tert-butyl peroxy (2-ethylhexanoate), and diethylene glycol methyl ether; S120, forming a second monomer mixture by combining styrene, methyl methacrylate, isobutyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, acrylic acid, diacetone acrylamide, ethylene glycol dimethacrylate, tert-butyl peroxy (2-ethylhexanoate), and diethylene glycol methyl ether; S130, adding diethylene glycol methyl ether to the reactor for the first time and stirring, heating to 130-140° C. under nitrogen protection, dripping the first monomer mixture, the dripping time of the first monomer mixture is controlled to be 3-4 hours, after the dripping is completed, continuing to drip the second monomer mixture, the dripping time of the second monomer mixture is controlled to be 1-2 hours, after the first heat preservation reaction for 0.3-1 hour, cooling to 110-125° C., dripping styrene, after the dripping is completed, adding diethylene glycol methyl ether for the second time, after the second heat preservation reaction for 1-2 hours, cooling to 70-90° C., adding N,N-dimethylethanolamine, after the third heat preservation reaction for 0.2-1 hour, adding deionized water, heating to 50-70° C. for the fourth heat preservation reaction for 0.2-1 hour, cooling to room temperature, and obtaining a hydroxy acrylic resin dispersion with a three-dimensional network cross-linked structure; The raw materials of the hydroxylated acrylic resin dispersion for water-based paint include the following components in parts by mass: 2-3 parts by mass of styrene; 7-8 parts by mass of methyl methacrylate; 23-24 parts by mass of isobutyl methacrylate; 2-3 parts by mass of hydroxypropyl methacrylate; 7-8 parts by mass of hydroxyethyl methacrylate; 0.5-1 parts by mass of acrylic acid; 0.1-0.5 parts by mass of diacetone acrylamide; 0.5-1.5 parts by mass of ethylene glycol dimethacrylate; 2-3 parts by mass of tert-butyl peroxy(2-ethylhexanoate); 2-3 parts by mass of diethylene glycol methyl ether; 1-2 parts by mass of N,N-dimethylethanolamine; 45-55 parts by mass of deionized water.

2. The method according to claim 1, characterized in that In step S110, the amount of styrene added is 55-57% of the total content of the raw materials; The amount of methyl methacrylate added is 69-71% of the total content of the raw materials; The amount of isobutyl methacrylate added is 69-71% of the total content of the raw materials; The amount of hydroxypropyl methacrylate added is 82-84% of the total content of the raw materials; The amount of hydroxyethyl methacrylate added is 65-67% of the total content of the raw materials; The amount of tert-butyl peroxy (2-ethylhexanoate) added is 69-71% of the total content of the raw materials; The added amount of diethylene glycol methyl ether is 14-16% of the total content of the raw materials.

3. The method according to claim 1, characterized in that In step S120, the amount of styrene added is 23-25% of the total content of the raw materials; The amount of methyl methacrylate added is 29-31% of the total content of the raw materials; The amount of isobutyl methacrylate added is 29-31% of the total content of the raw materials; The amount of hydroxypropyl methacrylate added is 16-18% of the total content of the raw materials; The amount of hydroxyethyl methacrylate added is 33-35% of the total content of the raw materials; The amount of acrylic acid added is 100% of the total content of the raw materials; The added amount of diacetone acrylamide is 100% of the total content of the raw materials; The added amount of ethylene glycol dimethacrylate is 100% of the total content of the raw materials; The amount of tert-butyl peroxy (2-ethylhexanoate) added is 29-31% of the total content of the raw materials; The added amount of the diethylene glycol methyl ether is 6-8% of the total content of the raw materials.

4. The method according to claim 1, characterized in that: In step S130, the content of the diethylene glycol methyl ether added for the first time is 75-77% of the total content of the raw materials; The amount of styrene added is 18-22% of the total content of the raw materials; The content of the diethylene glycol methyl ether added for the second time is 1-3% of the total content of the raw materials; The amount of N,N-dimethylethanolamine added is 100% of the total content of the raw materials.

5. The method according to claim 1, characterized in that The time for adding styrene dropwise is controlled at 0.2-0.5 hours.

6. A hydroxy acrylic resin dispersion for water-based paint, characterized in that: The hydroxy acrylic resin dispersion for water-based paint is prepared by the method according to any one of claims 1 to 5, and its raw materials include the following components in parts by weight: 2-3 parts by mass of styrene; 7-8 parts by mass of methyl methacrylate; 23-24 parts by mass of isobutyl methacrylate; 2-3 parts by mass of hydroxypropyl methacrylate; 7-8 parts by mass of hydroxyethyl methacrylate; 0.5-1 parts by mass of acrylic acid; 0.1-0.5 parts by mass of diacetone acrylamide; 0.5-1.5 parts by mass of ethylene glycol dimethacrylate; 2-3 parts by mass of tert-butyl peroxy(2-ethylhexanoate); 2-3 parts by mass of diethylene glycol methyl ether; 1-2 parts by mass of N,N-dimethylethanolamine; 45-55 parts by mass of deionized water.

7. A water-based paint, characterized in that: The water-based paint comprises an isocyanate crosslinking agent and the hydroxy acrylic resin dispersion according to claim 6.

Images