A paint for wall painting and a method for preparing the same

Abstract

This invention relates to a wall painting coating and its preparation method, belonging to the field of polymer coating technology. The wall painting coating of this invention comprises the following components in parts by weight: 35-45 parts of waterborne acrylic copolymer emulsion; 15-25 parts of waterborne iron oxide red paste; 1.8-2.5 parts of silane-modified attapulgite clay; 0.4-0.6 parts of associative polyurethane thickener; 0.6-1.0 parts of wood fiber; 0.8-1.2 parts of wetting and dispersing agent; 0.15-0.2 parts of defoamer; 2.0-3.0 parts of film-forming aid; and 31-33 parts of water. The wetting and dispersing agent is sorbitan monolaurate, N,N-bis(2-hydroxypropyl)-dodecanoamide, or N-tris(hydroxymethyl)methyl-citrate monohydrazide amide.

Description

Technical Field

[0001] This invention relates to a paint for wall painting and its preparation method, belonging to the field of polymer coating technology. Background Technology

[0002] With the increasing demand for personalized and artistic interior decoration, wall art painting (such as hand-painted murals, screen prints, and artistic reliefs) has gradually become one of the mainstream choices for interior decoration. Wall painting paint is a thick-paste decorative material applied to the interior and exterior walls of buildings to create decorative patterns, textures, or three-dimensional shapes. Unlike ordinary flat latex paint, wall painting paint not only needs good hiding power and weather resistance, but also places higher demands on its anti-sagging properties, thixotropy, and washability and adhesion after film formation. Especially when using techniques such as scraping, troweling, or roller coating to create three-dimensional textures, the paint system needs to have high viscosity under static conditions to maintain the shape, and can quickly thin under dynamic shear to ensure smooth application.

[0003] Currently, conventional methods for improving the thixotropic and anti-sagging properties of thick-film coatings typically rely on adding cellulose ether thickeners or inorganic thixotropic agents (such as bentonite and attapulgite). However, cellulose ether thickeners are susceptible to microbial attack in alkaline environments, leading to viscosity reduction, and excessive dosage can result in poor coating flow and leveling, making the paint film prone to brush marks. While unmodified ordinary attapulgite possesses certain thixotropic properties, its dispersion stability in organic emulsion systems is poor, easily leading to agglomeration and sedimentation, resulting in decreased coating storage stability, and its contribution to the coating's water resistance and mechanical strength is limited.

[0004] Furthermore, in colored paint systems with high pigment volume concentrations, the uniformity of pigment particle dispersion directly affects the coating's gloss, color fastness, and durability. While existing conventional surfactant-based wetting and dispersing agents can improve color development, their functionality in enhancing coating anti-sagging properties and resistance to chemical corrosion is relatively limited. Therefore, there is an urgent need to develop a wall painting coating that combines excellent anti-sagging workability, high thixotropic index, strong adhesion, washability, and long-lasting weather resistance. Summary of the Invention

[0005] The purpose of this invention is to provide a wall painting coating and its preparation method, so as to solve the problems of deviations in the anti-sagging construction properties, washability and weather resistance of current wall painting coatings.

[0006] This invention provides a wall painting coating, composed of the following components in parts by weight: 35-45 parts of water-based acrylic copolymer emulsion; 15-25 parts of water-based iron oxide red paste; 1.8-2.5 parts of silane-modified attapulgite; 0.4-0.6 parts of associative polyurethane thickener; 0.6-1.0 parts of wood fiber; 0.8-1.2 parts of wetting and dispersing agent; 0.15-0.2 parts of defoamer; 2.0-3.0 parts of film-forming aid; and 31-33 parts of water. The preparation method of the silane-modified attapulgite is as follows: attapulgite ore powder and hydrochloric acid are mixed at 6... The mixture was stirred at 0-70℃ for 2-3 hours to obtain acid-activated attapulgite. Then, the acid-activated attapulgite was dispersed in a solvent, and the pH was adjusted to 4.0-5.0. γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 70-75℃ for 4-5 hours to obtain silane-modified attapulgite. The wetting and dispersing agent was sorbitan monolaurate, N,N-bis(2-hydroxypropyl)-dodecanoamide, or N-tris(hydroxymethyl)methyl-citrate monohydrazide amide. The chemical structure of N-tris(hydroxymethyl)methyl-citrate monohydrazide amide is as follows:

[0007] .

[0008] Preferably, the attapulgite ore powder has an average diameter of 20-50 nm, an average length of 0.5-2 μm, and a cation exchange capacity of 25-35 mmol / 100g.

[0009] Preferably, the concentration of the hydrochloric acid is 2-3 mol / L, and the mass ratio of γ-aminopropyltriethoxysilane to acid-activated attapulgite is 7.5-9:50.

[0010] Preferably, the particle size of the silane-modified attapulgite is greater than 800 mesh.

[0011] Preferably, the average length of the wood fibers is 180~220μm and the average diameter is 10~20μm.

[0012] Preferably, the preparation method of the lignocellulose is as follows: bleached wood pulp with α-cellulose content ≥90% and kappa number ≤1.0 is dissociated, dried, and then screened to obtain the lignocellulose.

[0013] Preferably, the aqueous acrylic copolymer emulsion is prepared by emulsion polymerization of monomers including styrene, hexyl acrylate, methyl methacrylate, acrylic acid and N-hydroxymethylacrylamide.

[0014] Preferably, the method for preparing the aqueous acrylic copolymer emulsion includes the following steps:

[0015] (1) Styrene, hexyl acrylate, methyl methacrylate, acrylic acid and N-hydroxymethylacrylamide are added to a mixture composed of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether, sodium bicarbonate and water, and mixed evenly to obtain a monomer pre-emulsion; the mass ratio of styrene, hexyl acrylate, methyl methacrylate, acrylic acid, N-hydroxymethylacrylamide, sodium dodecyl sulfate, nonylphenol polyoxyethylene ether, sodium bicarbonate and water is 28~30:23~25:7~9:1~2:1.8~3:0.7~1:0.7~1:0.2~0.5:13.5~15;

[0016] (2) After mixing the monomer preemulsion, ammonium persulfate and water, heat to 80~85℃ and react for 30~45 min to obtain seed emulsion; the mass ratio of the monomer preemulsion, ammonium persulfate and water is 7~10:0.1~0.3:31.5~35;

[0017] (3) Add the monomer pre-emulsion and ammonium persulfate solution dropwise to the seed emulsion, control the system temperature at 83~87℃, raise the temperature to 88~90℃ after the addition is complete, mix and react for 1~2h, cool down and adjust the pH to 7.0~8.0 to obtain an aqueous acrylic copolymer emulsion; the mass fraction of the ammonium persulfate solution is 7~9%, and the mass ratio of ammonium persulfate in the monomer pre-emulsion, seed emulsion and ammonium persulfate solution is 55~58:35~45:0.25~0.5.

[0018] Preferably, the preparation method of the associative polyurethane thickener includes the following steps: under the action of a catalyst, isophorone diisocyanate, polyethylene glycol PEG-6000 and trimethylolpropane are mixed and reacted, then dimethylolpropionic acid is added for chain extension reaction, and finally a monohydric alcohol compound is added for end capping, followed by neutralization and dispersion with water to obtain the product; the monohydric alcohol compound is n-dodecyl alcohol or n-tetradecyl alcohol; the molar ratio of isophorone diisocyanate, polyethylene glycol PEG-6000, trimethylolpropane, dimethylolpropionic acid and the monohydric alcohol compound is 0.11~0.13:0.01~0.015:0.01~0.015:0.06~0.07:0.05~0.06.

[0019] A method for preparing a wall painting coating as described above includes the following steps: mixing waterborne acrylic copolymer emulsion, waterborne iron oxide red paste, silane-modified attapulgite clay, associative polyurethane thickener, wood fiber, wetting and dispersing agent, defoamer, film-forming aid and water in the prescribed amounts until homogeneous, thereby obtaining the coating.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) This invention constructs a stable three-dimensional thixotropic network in the coating system by compounding wood fibers with silane-modified attapulgite clay and combining it with an associative polyurethane thickener with a specific structure. Test results show that the wall painting coating of this invention has a large anti-sagging wet film thickness and a high thixotropic index. This indicates that the coating has excellent shaping ability under static conditions, which can meet the construction requirements of three-dimensional modeling such as thick paste textured painting and relief printing, and has moderate viscosity and smooth application during dynamic construction.

[0022] (2) This invention synthesizes N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazide amide containing a hydroxymethyl structure, which is used as a wetting and dispersing agent to help enhance the crosslinking density and compactness of the coating film. Test data show that the coating using this dispersant has good resistance to saturated calcium hydroxide solution, 10% acetic acid solution and ethanol. At the same time, the coating exhibits excellent scrub resistance and abrasion resistance.

[0023] (3) Through the synergistic effect of the water-based acrylic copolymer emulsion and the modified filler, the coating exhibits a grade 0 adhesion on the cement substrate. In addition, in the test of artificial aging for 3000 hours, the coating has a low color difference value, indicating that the coating of the present invention can effectively resist ultraviolet aging, has good color retention, and is suitable for long-term outdoor wall decoration. Attached Figure Description

[0024] Figure 1 The above is the 1H NMR spectrum of the intermediate prepared in Example 5 of this invention;

[0025] Figure 2 The image shows the 1H NMR spectrum of N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazide amide prepared in Example 5 of this invention. Detailed Implementation

[0026] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the present invention.

[0027] Example 1

[0028] The wall painting coating of this embodiment is composed of the following components in parts by weight: 40 parts of waterborne acrylic copolymer emulsion, 20 parts of waterborne iron oxide red paste, 2.0 parts of silane-modified attapulgite clay, 0.5 parts of associative polyurethane thickener, 0.8 parts of wood fiber, 1.0 part of wetting and dispersing agent, 0.2 parts of defoamer, 2.5 parts of film-forming aid, and 33 parts of deionized water. Specifically, the waterborne iron oxide red paste is BASF Luconyl waterborne iron oxide red paste 3396, the associative polyurethane thickener is Haiming Sideqian DEURHEO WT-105A rheology modifier, the wetting and dispersing agent is sorbitan monolaurate, the defoamer is BASF FoamStar® SI 2250 silicone defoamer, and the film-forming aid is dodecyl alcohol ester.

[0029] The preparation method of the aqueous acrylic copolymer emulsion is as follows:

[0030] (1) Add 0.7 parts by weight of sodium dodecyl sulfate, 0.7 parts by weight of nonylphenol polyoxyethylene ether and 0.2 parts by weight of sodium bicarbonate to 13.5 parts by weight of deionized water and stir until the solid is fully dissolved. Under stirring conditions of 1000 r / min, add 28 parts by weight of styrene, 23 parts by weight of hexyl acrylate, 7 parts by weight of methyl methacrylate, 1.0 parts by weight of acrylic acid and 1.8 parts by weight of N-hydroxymethylacrylamide in sequence. After the addition is complete, continue stirring for 30 min to obtain monomer pre-emulsion.

[0031] (2) In a four-necked flask equipped with a stirrer, condenser, thermometer and constant pressure dropping funnel, add 31.5 parts by mass of deionized water, 10% of the total mass of the monomer pre-emulsion prepared in step (1) and 0.1 parts by mass of ammonium persulfate. After passing nitrogen gas through, stir evenly, then heat to 80°C and keep warm and stir for 45 min to obtain seed emulsion.

[0032] (3) Under stirring and nitrogen protection, the remaining monomer pre-emulsion and initiator solution (0.25 parts by mass of ammonium persulfate dissolved in 3 parts by mass of deionized water) prepared in step (1) are added dropwise to the seed emulsion through two constant pressure dropping funnels. During the dropping process, the reaction temperature is maintained at 83~87℃, and the dropping rate of monomer pre-emulsion and initiator solution is controlled to ensure that both are added at the same time (dropping time is 4h). After the dropping is completed, the temperature is raised to 88℃ and stirred for 1h. After the reaction is completed, the temperature is lowered to below 40℃, and the pH of the system is adjusted to 7.0 with 25% ammonia water. The material is filtered out with a 200-mesh filter to obtain the waterborne acrylic copolymer emulsion.

[0033] The preparation method of silane-modified attapulgite is as follows:

[0034] (1) 100g of raw attapulgite ore powder (the average diameter of the raw attapulgite ore powder is 30nm, the average length is 1μm, and the cation exchange capacity is 30mmol / 100g) was added to 1000mL of hydrochloric acid with a concentration of 2mol / L. The mixture was heated to 60℃ and stirred for 2h. After centrifugation, the solid obtained was washed with deionized water until the washing liquid was neutral. The washed solid was then dried at 120℃ to constant weight, ground through a 200-mesh sieve, and the sieve residue was collected to obtain acid-activated attapulgite.

[0035] (2) 50g of acid-activated attapulgite was dispersed in 500mL of a mixed solvent of ethanol and deionized water with a volume ratio of 9:1. The mixture was ultrasonically dispersed for 30min. The pH of the system was adjusted to 4.5 with glacial acetic acid. Then, 7.5g of γ-aminopropyltriethoxysilane was added dropwise. After the addition was completed, the mixture was stirred and refluxed at 75℃ for 4h. After the reaction was completed, the solid product was centrifuged and washed three times with anhydrous ethanol. Finally, the washed solid product was vacuum dried at 80℃ for 12h. After grinding, the solid product was passed through an 800-mesh sieve, and the sieve residue was collected to obtain silane-modified attapulgite.

[0036] The preparation method of wood fiber is as follows: bleached wood pulp with α-cellulose content ≥90% and kappa number ≤1.0 is dissociated using a fiber decongester, dried, and then screened to obtain fibers with an average length of 200μm and an average diameter of 15μm.

[0037] Example 2

[0038] The wall painting coating of this embodiment is composed of the following components in parts by weight: 35 parts of waterborne acrylic copolymer emulsion, 25 parts of waterborne iron oxide red paste, 2.5 parts of silane-modified attapulgite clay, 0.6 parts of associative polyurethane thickener, 1.0 part of wood fiber, 1.2 parts of wetting and dispersing agent, 0.2 parts of defoamer, 2.0 parts of film-forming aid, and 32 parts of deionized water. Specifically, the waterborne iron oxide red paste is BASF Luconyl waterborne iron oxide red paste 3396, the associative polyurethane thickener is Haiming Sideqian DEURHEO WT-105A rheology modifier, the wetting and dispersing agent is sorbitan monolaurate, the defoamer is BASF FoamStar® SI 2250 silicone defoamer, and the film-forming aid is dodecyl alcohol ester.

[0039] The preparation method of the aqueous acrylic copolymer emulsion is as follows:

[0040] (1) Add 0.7 parts by weight of sodium dodecyl sulfate, 0.7 parts by weight of nonylphenol polyoxyethylene ether and 0.2 parts by weight of sodium bicarbonate to 13.5 parts by weight of deionized water and stir until the solid is fully dissolved. Under stirring conditions of 900 r / min, add 28 parts by weight of styrene, 23 parts by weight of hexyl acrylate, 7 parts by weight of methyl methacrylate, 1.0 parts by weight of acrylic acid and 1.8 parts by weight of N-hydroxymethylacrylamide in sequence. After the addition is complete, continue stirring for 30 min to obtain monomer pre-emulsion.

[0041] (2) In a four-necked flask equipped with a stirrer, condenser, thermometer and constant pressure dropping funnel, add 31.5 parts by mass of deionized water, 12% of the total mass of the monomer pre-emulsion prepared in step (1) and 0.1 parts by mass of ammonium persulfate. After passing nitrogen gas through, stir evenly, then heat to 82°C and keep warm and stir for 40 min to obtain seed emulsion.

[0042] (3) Under stirring and nitrogen protection, the remaining monomer pre-emulsion and initiator solution (0.25 parts by mass of ammonium persulfate dissolved in 3 parts by mass of deionized water) prepared in step (1) are added dropwise to the seed emulsion through two constant pressure dropping funnels. During the dropping process, the reaction temperature is maintained at 83~87℃, and the dropping rate of monomer pre-emulsion and initiator solution is controlled to ensure that both are added at the same time (dropping time is 3.5h). After the dropping is completed, the temperature is raised to 90℃ and stirred for 1h. After the reaction is completed, the temperature is lowered to below 40℃, and the pH of the system is adjusted to 7.5 with 26% ammonia water. The material is filtered out with a 200-mesh filter to obtain the waterborne acrylic copolymer emulsion.

[0043] The preparation method of silane-modified attapulgite is as follows:

[0044] (1) 100g of raw attapulgite ore powder (the average diameter of the raw attapulgite ore powder is 20nm, the average length is 0.5μm, and the cation exchange capacity is 25mmol / 100g) was added to 1000mL of hydrochloric acid with a concentration of 2mol / L. The mixture was heated to 60℃ and stirred for 2h. After centrifugation, the solid obtained was washed with deionized water until the washing liquid was neutral. The washed solid was then dried at 120℃ to constant weight, ground through a 200-mesh sieve, and the sieve residue was collected to obtain acid-activated attapulgite.

[0045] (2) 50g of acid-activated attapulgite was dispersed in 500mL of a mixed solvent of ethanol and deionized water with a volume ratio of 9:1. The mixture was ultrasonically dispersed for 30min. The pH of the system was adjusted to 4.0 with glacial acetic acid. Then, 7.5g of γ-aminopropyltriethoxysilane was added dropwise. After the addition was completed, the mixture was stirred and refluxed at 75℃ for 4h. After the reaction was completed, the solid product was centrifuged and washed three times with anhydrous ethanol. Finally, the washed solid product was vacuum dried at 80℃ for 12h. After grinding, the solid product was passed through an 800-mesh sieve. The sieve residue was collected to obtain silane-modified attapulgite.

[0046] The preparation method of wood fiber is as follows: bleached wood pulp with α-cellulose content ≥90% and kappa number ≤1.0 is dissociated using a fiber decongester, dried, and then screened to obtain fibers with an average length of 180μm and an average diameter of 10μm.

[0047] Example 3

[0048] The wall painting coating of this embodiment is composed of the following components in parts by weight: 45 parts of waterborne acrylic copolymer emulsion, 15 parts of waterborne iron oxide red paste, 1.8 parts of silane-modified attapulgite clay, 0.4 parts of associative polyurethane thickener, 0.6 parts of wood fiber, 0.8 parts of wetting and dispersing agent, 0.15 parts of defoamer, 3.0 parts of film-forming aid, and 31 parts of deionized water. Specifically, the waterborne iron oxide red paste is BASF Luconyl waterborne iron oxide red paste 3396, the associative polyurethane thickener is Haiming Sideqian DEURHEO WT-105A rheology modifier, the wetting and dispersing agent is sorbitan monolaurate, the defoamer is BASF FoamStar® SI 2250 silicone defoamer, and the film-forming aid is dodecyl alcohol ester.

[0049] The preparation method of the aqueous acrylic copolymer emulsion is as follows:

[0050] (1) Add 0.7 parts by weight of sodium dodecyl sulfate, 0.7 parts by weight of nonylphenol polyoxyethylene ether and 0.2 parts by weight of sodium bicarbonate to 13.5 parts by weight of deionized water and stir until the solid is fully dissolved. Under stirring conditions of 800 r / min, add 28 parts by weight of styrene, 23 parts by weight of hexyl acrylate, 7 parts by weight of methyl methacrylate, 1.0 parts by weight of acrylic acid and 1.8 parts by weight of N-hydroxymethylacrylamide in sequence. After the addition is complete, continue stirring for 30 min to obtain monomer pre-emulsion.

[0051] (2) In a four-necked flask equipped with a stirrer, condenser, thermometer and constant pressure dropping funnel, add 31.5 parts by mass of deionized water, 15% of the total mass of the monomer pre-emulsion prepared in step (1) and 0.1 parts by mass of ammonium persulfate. After passing nitrogen gas through, stir evenly, then heat to 85°C and keep warm and stir for 30 min to obtain seed emulsion.

[0052] (3) Under stirring and nitrogen protection, the remaining monomer pre-emulsion and initiator solution (0.25 parts by mass of ammonium persulfate dissolved in 3 parts by mass of deionized water) prepared in step (1) are added dropwise to the seed emulsion through two constant pressure dropping funnels. During the dropping process, the reaction temperature is maintained at 83~87℃, and the dropping rate of monomer pre-emulsion and initiator solution is controlled to ensure that both are added at the same time (dropping time is 4h). After the dropping is completed, the temperature is raised to 90℃ and stirred for 1h. After the reaction is completed, the temperature is lowered to below 40℃, and the pH of the system is adjusted to 8.0 with 28% ammonia water. The material is filtered out with a 200-mesh filter to obtain the waterborne acrylic copolymer emulsion.

[0053] The preparation method of silane-modified attapulgite is as follows:

[0054] (1) 100g of raw attapulgite ore powder (the average diameter of the raw attapulgite ore powder is 50nm, the average length is 2μm, and the cation exchange capacity is 35mmol / 100g) was added to 1000mL of hydrochloric acid with a concentration of 2mol / L. The mixture was heated to 60℃ and stirred for 2h. After centrifugation, the solid obtained was washed with deionized water until the washing liquid was neutral. The washed solid was then dried at 120℃ to constant weight, ground through a 200-mesh sieve, and the sieve residue was collected to obtain acid-activated attapulgite.

[0055] (2) 50g of acid-activated attapulgite was dispersed in 500mL of a mixed solvent of ethanol and deionized water with a volume ratio of 9:1. The mixture was ultrasonically dispersed for 30min. The pH of the system was adjusted to 5.0 with glacial acetic acid. Then, 7.5g of γ-aminopropyltriethoxysilane was added dropwise. After the addition was completed, the mixture was stirred and refluxed at 75℃ for 4h. After the reaction was completed, the solid product was centrifuged and washed three times with anhydrous ethanol. Finally, the washed solid product was vacuum dried at 80℃ for 12h. After grinding, the solid product was passed through an 800-mesh sieve. The sieve residue was collected to obtain silane-modified attapulgite.

[0056] The preparation method of wood fiber is as follows: bleached wood pulp with α-cellulose content ≥90% and kappa number ≤1.0 is dissociated using a fiber decongester, dried, and then screened to obtain fibers with an average length of 220μm and an average diameter of 20μm.

[0057] Example 4

[0058] The difference between the wall painting coating of this embodiment and the wall painting coating of Example 1 is only that the wetting and dispersing agent in the wall painting coating of this embodiment is N,N-bis(2-hydroxypropyl)-dodecanoamide.

[0059] Example 5

[0060] The difference between the wall painting paint of this embodiment and the wall painting paint of Example 1 is only that the wetting and dispersing agent in the wall painting paint of this embodiment is N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazide amide; the preparation method of N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazide amide is as follows:

[0061] (1) Dissolve 0.08 mol of monomethyl citrate in 60 mL of anhydrous tetrahydrofuran, then add 0.08 mol of N-hydroxysuccinimide and 0.08 mol of dicyclohexylcarbodiimide, stir at 0 °C for 1 h, then filter, cool the filtrate to 0 °C, and then add dropwise a 20% mass fraction anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine (the amount of tert-butyloxycarbonylhydrazine in the anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine is 0.08 mol). After the addition is completed, stir the reaction at room temperature for 6 h, and then distill the reaction solution under reduced pressure. Concentrate to dryness, then add 15 mL of ethyl acetate, heat to 60°C and stir to fully dissolve the concentrate. Filter while hot to remove insoluble matter. Add 40 mL of petroleum ether to the filtrate to obtain a mixture. Let the mixture stand at room temperature for 2 hours, then transfer to a 4°C refrigerator and refrigerate for 12 hours. Filter while cold. Wash the filter cake twice with a 1:3 (v / v) mixture of ethyl acetate and petroleum ether at 4°C (10 mL of mixed solvent per wash). Dry the washed solid under vacuum at 40°C to constant weight to obtain the intermediate, with a yield of 73%. The 1H NMR spectrum of the intermediate is shown below. Figure 1 As shown, the chemical structure is as follows:

[0062] .

[0063] (2) Add 0.035 mol of the intermediate to 50 mL of deionized water and stir until the intermediate is fully dissolved. Then add 0.042 mol of tris(hydroxymethyl)aminomethane and adjust the pH to 6.0 with 1 mol / L sodium hydroxide solution. Then add 0.042 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and stir the reaction at room temperature for 12 h. After the reaction is complete, add 1 mol / L hydrochloric acid dropwise to the reaction solution to adjust the pH to 2.0. Then continue stirring the reaction at room temperature for 1 h. Then add 1 mol / L sodium hydroxide solution to adjust the pH of the system to 6.5. Then concentrate the solution under reduced pressure to a volume of 1 Add 5 mL of the concentrate to 40 mL of anhydrous ethanol, stir well, and transfer to a 4°C refrigerator to stand for 12 h. Then, filter while cold. Wash the filter cake twice with anhydrous ethanol at 4°C (20 mL of anhydrous ethanol each time). The washed filter cake is the crude product. Add the crude product to 30 mL of a mixed solvent of anhydrous ethanol and deionized water in a volume ratio of 3:1. Heat to 60°C and stir until the crude product is fully dissolved. Then filter while hot. After the filtrate cools naturally to room temperature, transfer to a 4°C refrigerator to stand for 12 h. Then filter while cold. Dry the filter cake under vacuum at 40°C to constant weight to obtain N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazideamide. The 1H NMR spectrum of N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazideamide is shown below. Figure 2 As shown, the chemical structure is as follows:

[0064] .

[0065] Example 6

[0066] The difference between the wall painting coating of this embodiment and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this embodiment is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the temperature is raised to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000 which has been vacuum dehydrated at 110°C and 0.01 mol of trimethylolpropane are added. The mixture was added to a four-necked flask and stirred at 70°C for 2 hours. The reaction mixture was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-dodecyl alcohol were added. The mixture was stirred at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0067] Example 7

[0068] The difference between the wall painting coating of this embodiment and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this embodiment is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the temperature is raised to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000 which has been vacuum dehydrated at 110°C and 0.01 mol of trimethylolpropane are added. The mixture was added to a four-necked flask and stirred at 70°C for 2 hours. The reaction mixture was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-tetradecyl alcohol were added. The mixture was stirred at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0069] Example 8

[0070] The difference between the wall painting coating of this embodiment and the wall painting coating of Example 5 is that the associative polyurethane thickener in the wall painting coating of this embodiment is the associative polyurethane thickener used in Example 6.

[0071] Example 9

[0072] The difference between the wall painting coating of this embodiment and the wall painting coating of Example 5 is that the associative polyurethane thickener in the wall painting coating of this embodiment is the associative polyurethane thickener used in Example 7.

[0073] The preparation method of the wall painting paint in Examples 1-9 includes the following steps:

[0074] Deionized water, wetting and dispersing agent, and defoamer were added to a dispersion container and stirred evenly at 300 rpm. Then, under high-speed dispersion conditions at 1800 rpm, silane-modified attapulgite and wood fibers were added sequentially and dispersed for 20 min. Subsequently, the speed was reduced to 1200 rpm, and waterborne acrylic copolymer emulsion, waterborne iron oxide red paste, and film-forming aid were added, and stirring was continued for 15 min. Finally, associative polyurethane thickener was added and stirred evenly at 600 rpm to obtain the wall painting coating.

[0075] Comparative Example 1

[0076] The only difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is that the wall painting coating of this comparative example contains 2.8 parts by mass of silane-modified attapulgite and 0 parts by mass of wood fiber.

[0077] Comparative Example 2

[0078] The only difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is that the wall painting coating of this comparative example contains 0 parts by mass of silane-modified attapulgite and 2.8 parts by mass of wood fiber.

[0079] Comparative Example 3

[0080] The only difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is that the wood fiber in the wall painting coating of this comparative example is replaced with sepiolite fiber, and the sepiolite fiber has an average length of 200 μm and an average diameter of 15 μm.

[0081] Comparative Example 4

[0082] The difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this comparative example is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the temperature is raised to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000, which has been vacuum dehydrated at 110°C, and 0.01 mol of trimethylolpropionic acid are added. Alkane was added to a four-necked flask, and the mixture was stirred and kept at 70°C for 2 hours. The reaction system was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-octanol were added. The mixture was stirred and kept at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0083] Comparative Example 5

[0084] The difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this comparative example is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the temperature is raised to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000 which has been vacuum dehydrated at 110°C and 0.01 mol of trimethylolpropane are added. The mixture was added to a four-necked flask and stirred at 70°C for 2 hours. The reaction mixture was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-hexadecyl alcohol were added. The mixture was stirred at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0085] Comparative Example 6

[0086] The difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this comparative example is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the mixture is heated to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000, which has been vacuum dehydrated at 110°C, and 0.015 mol of 1,6-hexanediol are added. Alcohol was added to a four-necked flask and the mixture was stirred at 70°C for 2 hours. The reaction system was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-dodecyl alcohol was added. The mixture was stirred at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0087] Comparative Example 7

[0088] The difference between the wall painting coating of this comparative example and the wall painting coating of Example 1 is only that the associative polyurethane thickener in the wall painting coating of this comparative example is prepared by the following method: 0.11 mol of isophorone diisocyanate and 0.1 g of dibutyltin dilaurate are added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen delivery tube, and the temperature is raised to 55°C. Then, 0.01 mol of polyethylene glycol PEG-6000 which has been vacuum dehydrated at 110°C and 0.0075 mol of pentaerythritol are added. The mixture was added to a four-necked flask and stirred at 70°C for 2 hours. The reaction mixture was then cooled to 55°C, and 0.06 mol of dimethylolpropionic acid and 25 g of butanone were added to adjust the viscosity. The mixture was then heated to 70°C and stirred for 2.5 hours. The mixture was then cooled to 50°C, and 0.05 mol of n-dodecyl alcohol were added. The mixture was stirred at 60°C for 1.5 hours. Butanone was removed by vacuum distillation, and deionized water was added to adjust the solid content to 25%. The mixture was then neutralized with triethylamine to a pH of 7.0-7.5 to obtain an associative polyurethane thickener.

[0089] Comparative Example 8

[0090] The difference between the wall painting paint of this comparative example and the wall painting paint of Example 5 lies only in the preparation method of the wetting and dispersing agent in the wall painting paint of this comparative example:

[0091] (1) Dissolve 0.08 mol of monomethyl citrate in 60 mL of anhydrous tetrahydrofuran, then add 0.08 mol of N-hydroxysuccinimide and 0.08 mol of dicyclohexylcarbodiimide, stir at 0 °C for 1 h, then filter, cool the filtrate to 0 °C, and then add dropwise a 20% (w / w) anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine (the amount of tert-butyloxycarbonylhydrazine in the anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine is 0.08 mol). After the addition is complete, stir the reaction at room temperature for 6 h, and then reduce the reaction solution... The solution was concentrated to dryness by pressure distillation, then 15 mL of ethyl acetate was added. The mixture was heated to 60°C and stirred to fully dissolve the concentrate. The solution was then filtered while hot to remove insoluble matter. 40 mL of petroleum ether was added to the filtrate to obtain a mixture. The mixture was allowed to stand at room temperature for 2 hours, then transferred to a refrigerator at 4°C and refrigerated for 12 hours. The mixture was then filtered while cold. The filter cake was washed twice with a 1:3 (v / v) mixture of ethyl acetate and petroleum ether at 4°C (10 mL of the mixed solvent was used for each wash). The washed solid was dried under vacuum at 40°C to constant weight to obtain the intermediate. The chemical structure of the intermediate is as follows:

[0092] .

[0093] (2) Add 0.035 mol of the intermediate to 50 mL of deionized water and stir until the intermediate is completely dissolved. Then add 0.042 mol of ethanolamine and adjust the pH to 6.0 with 1 mol / L sodium hydroxide solution. Then add 0.042 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and stir the reaction at room temperature for 12 h. After the reaction is completed, add 1 mol / L hydrochloric acid dropwise to the reaction solution to adjust the pH to 2.0. Then continue stirring the reaction at room temperature for 1 h. Then add 1 mol / L sodium hydroxide solution to adjust the pH of the system to 6.5. Then concentrate by vacuum distillation. To a volume of 15 mL, add 40 mL of anhydrous ethanol to the concentrate, stir well, and transfer to a 4°C refrigerator to stand for 12 hours. Then, filter while cold. Wash the filter cake twice with anhydrous ethanol at 4°C (20 mL of anhydrous ethanol each time). The washed filter cake is the crude product. Add the crude product to 30 mL of a mixed solvent consisting of anhydrous ethanol and deionized water in a volume ratio of 3:1. Heat to 60°C and stir until the crude product is fully dissolved. Then, filter while hot. After the filtrate has cooled naturally to room temperature, transfer to a 4°C refrigerator to stand for 12 hours. Then, filter while cold. Dry the filter cake under vacuum at 40°C to constant weight to obtain the wetting and dispersing agent. The chemical structure of the wetting and dispersing agent is as follows:

[0094] .

[0095] Comparative Example 9

[0096] The difference between the wall painting paint of this comparative example and the wall painting paint of Example 5 lies only in the preparation method of the wetting and dispersing agent in the wall painting paint of this comparative example:

[0097] (1) Dissolve 0.08 mol of monomethyl citrate in 60 mL of anhydrous tetrahydrofuran, then add 0.08 mol of N-hydroxysuccinimide and 0.08 mol of dicyclohexylcarbodiimide, stir at 0 °C for 1 h, then filter, cool the filtrate to 0 °C, and then add dropwise a 20% (w / w) anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine (the amount of tert-butyloxycarbonylhydrazine in the anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine is 0.08 mol). After the addition is complete, stir the reaction at room temperature for 6 h, and then reduce the reaction solution... The solution was concentrated to dryness by pressure distillation, then 15 mL of ethyl acetate was added. The mixture was heated to 60°C and stirred to fully dissolve the concentrate. The solution was then filtered while hot to remove insoluble matter. 40 mL of petroleum ether was added to the filtrate to obtain a mixture. The mixture was allowed to stand at room temperature for 2 hours, then transferred to a refrigerator at 4°C and refrigerated for 12 hours. The mixture was then filtered while cold. The filter cake was washed twice with a 1:3 (v / v) mixture of ethyl acetate and petroleum ether at 4°C (10 mL of the mixed solvent was used for each wash). The washed solid was dried under vacuum at 40°C to constant weight to obtain the intermediate. The chemical structure of the intermediate is as follows:

[0098] .

[0099] (2) Add 0.035 mol of the intermediate to 50 mL of deionized water and stir until the intermediate is fully dissolved. Then add 0.042 mol of glucosamine and adjust the pH to 6.0 with 1 mol / L sodium hydroxide solution. Then add 0.042 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and stir the reaction at room temperature for 12 h. After the reaction is complete, add 1 mol / L hydrochloric acid dropwise to the reaction solution to adjust the pH to 2.0. Then continue stirring the reaction at room temperature for 1 h. Then add 1 mol / L sodium hydroxide solution to adjust the pH of the system to 6.5. Then distill the concentrated solution under reduced pressure. Reduce the volume to 15 mL, add 40 mL of anhydrous ethanol to the concentrate, stir well, and transfer to a 4°C refrigerator to stand for 12 hours. Then, filter while cold. Wash the filter cake twice with anhydrous ethanol at 4°C (20 mL of anhydrous ethanol each time). The washed filter cake is the crude product. Add the crude product to 30 mL of a mixed solvent of anhydrous ethanol and deionized water in a volume ratio of 3:1, heat to 60°C, and stir until the crude product is fully dissolved. Then filter while hot. After the filtrate cools naturally to room temperature, transfer to a 4°C refrigerator to stand for 12 hours, and then filter while cold. Dry the filter cake under vacuum at 40°C to constant weight to obtain the wetting and dispersing agent. The chemical structure of the wetting and dispersing agent is as follows:

[0100] .

[0101] Comparative Example 10

[0102] The difference between the wall painting paint of this comparative example and the wall painting paint of Example 5 lies only in the preparation method of the wetting and dispersing agent in the wall painting paint of this comparative example:

[0103] (1) Dissolve 0.08 mol of monomethyl citrate in 60 mL of anhydrous tetrahydrofuran, then add 0.08 mol of N-hydroxysuccinimide and 0.08 mol of dicyclohexylcarbodiimide, stir at 0 °C for 1 h, then filter, cool the filtrate to 0 °C, and then add dropwise a 20% mass fraction anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine (the amount of tert-butyloxycarbonylhydrazine in the anhydrous tetrahydrofuran solution of tert-butyloxycarbonylhydrazine is 0.08 mol). After the addition is completed, stir the reaction at room temperature for 6 h, and then distill the reaction solution under reduced pressure. Concentrate to dryness, then add 15 mL of ethyl acetate, heat to 60°C and stir to fully dissolve the concentrate. Filter while hot to remove insoluble matter. Add 40 mL of petroleum ether to the filtrate to obtain a mixture. Let the mixture stand at room temperature for 2 hours, then transfer to a 4°C refrigerator and refrigerate for 12 hours. Filter while cold. Wash the filter cake twice with a 1:3 (v / v) mixture of ethyl acetate and petroleum ether at 4°C (10 mL of mixed solvent per wash). Dry the washed solid under vacuum at 40°C to constant weight to obtain the intermediate, with a yield of 73%. The chemical structure of the intermediate is as follows:

[0104] .

[0105] (2) Add the intermediate obtained in step (1) to 50 mL of a mixed solvent of methanol and deionized water with a volume ratio of 1:1, stir until the intermediate is fully dissolved, then add 1 mol / L hydrochloric acid to adjust the pH of the system to 2.0, continue stirring the reaction at room temperature for 1 h, then add 1 mol / L sodium hydroxide solution to adjust the pH of the system to 6.5, then concentrate under reduced pressure to a volume of 15 mL, add 40 mL of anhydrous ethanol to the concentrate, stir evenly, transfer to a 4 °C refrigerator and let stand for 12 h, then filter while cold, the filter cake The solution was washed twice with anhydrous ethanol at 4°C (20 mL of anhydrous ethanol was used for each wash). The filter cake after washing was the crude product. The crude product was added to 30 mL of a mixed solvent consisting of anhydrous ethanol and deionized water in a volume ratio of 3:1. The mixture was heated to 60°C and stirred until the crude product was fully dissolved. The solution was then filtered while hot. After the filtrate cooled naturally to room temperature, it was transferred to a refrigerator at 4°C and allowed to stand for 12 hours. The solution was then filtered while cold. The filter cake was vacuum dried at 40°C to constant weight to obtain monomethyl citrate monohydrazide. The chemical structure of monomethyl citrate monohydrazide is as follows:

[0106] .

[0107] (3) Mix monomethyl citrate monohydrazide and tri(hydroxymethyl)propane at a molar ratio of 1:1 to obtain a wetting and dispersing agent.

[0108] Experimental Example

[0109] To examine the comprehensive performance of the wall painting coatings in each embodiment and comparative example, the anti-sagging properties, thixotropic index, adhesion, water resistance, solvent resistance, scrub resistance, abrasion resistance, and weather resistance of the wall painting coatings in each embodiment and comparative example were tested. The anti-sagging property was tested according to the method in standard GB / T 9264-2012 "Evaluation of Anti-sagging Properties of Paints and Varnishes". A sag tester was used to apply wet films of different thicknesses to a glass plate, which was then placed vertically, and the maximum wet film thickness at which sagging occurred was recorded. The thixotropic index was tested as follows: the apparent viscosity η6 of the wall painting coating at 6 rpm and the apparent viscosity η60 at 60 rpm were measured using a rotational viscometer. Then, the thixotropic index TI value was calculated as η6 / η60. The higher the TI value, the stronger the thixotropy, and the better it is for three-dimensional modeling. Adhesion was tested according to the method specified in standard GB / T 9286-2021. The specific test method is as follows: Paint for wall painting was brushed onto the test board and allowed to cure and dry at room temperature for 7 days. Then, five parallel cuts were made along the long side of the test board, both parallel and perpendicular, penetrating the coating. Each cut was spaced 1 mm apart. A tear test was then performed using adhesive tape. Based on the degree of coating damage after tearing, the adhesion of the paint was rated according to the provisions of standard GB / T 9286-2021. The test board material was cement. Each sample was tested three times, and the average of the three test results was taken as the final result. Water resistance and solvent resistance were tested according to the methods specified in standard GB / T 9274-1988 "Determination of Resistance to Liquid Media for Paints and Varnishes". The specific test method is as follows: Paint for wall painting was brushed onto a tinplate and allowed to cure and dry at room temperature for 7 days. The edges and back of the tinplate were then sealed with paraffin wax. The tinplate was then immersed in water or the test solvent, sealed, and the time it took for the coating surface to change color, blister, peel, chalk, or soften was observed and recorded. The test solvents were saturated calcium hydroxide solution, 10% acetic acid solution, or ethanol. Each sample was tested three times, and the average of the three test results was taken as the final result. Scrub resistance was determined according to the methods in standard GB / T 9266-2009, measuring the number of scrub cycles the coating formed by the paint for wall painting could withstand. Abrasion resistance was tested using an abrasion tester with a rubber grinding wheel under a load of 500g and a rotation speed of 500r. The weight loss of the coating during the test (abrasion amount) was used to evaluate abrasion resistance. Each sample was tested three times, and the average of the three results was taken as the final result. Weather resistance was tested according to the method specified in standard GB / T 1865-2009. The specific test method is as follows: Wall painting paint was brushed onto a glass plate, then allowed to cure and dry at room temperature for 7 days. The coated side of the glass plate was then placed in an artificial aging test chamber for weather resistance testing. The absolute value ΔC of the color difference between the coating before aging and after 3000 hours of aging was calculated.Each sample was tested three times, and the average of the three test results was used as the final result.

[0110] The test results for the anti-sagging, thixotropic index, adhesion, water resistance, solvent resistance, scrub resistance, abrasion resistance, and weather resistance of the wall painting coatings of each embodiment and comparative example are shown in Table 1.

[0111] Table 1. Comprehensive Performance of Paints for Wall Painting

[0112]

[0113] As can be seen from the test results in Table 1, the wall painting coatings provided in Examples 1-9 of the present invention exhibit superior comprehensive performance in terms of anti-sagging, thixotropic index, adhesion, media resistance, scrub resistance, abrasion resistance, and weather resistance.

[0114] As shown in Example 1 and Comparative Examples 1-3, by using silane-modified attapulgite in combination with wood fibers, the coating exhibits a greater anti-sagging wet film thickness and thixotropic index. In contrast, Comparative Example 1, without the addition of wood fibers and only increasing the amount of silane-modified attapulgite, showed a decrease in anti-sagging properties, a lower thixotropic index, and reduced abrasion resistance and weather resistance; this indicates that the lack of physical interweaving of fibrous fillers affects the rheological resistance and density of the coating. Comparative Example 2, without the addition of silane-modified attapulgite and relying solely on wood fibers, showed a poorer anti-sagging property and a lower abrasion resistance compared to Example 1; this demonstrates that the synergistic effect of silane-modified attapulgite and wood fibers helps improve the barrier properties and mechanical strength of the coating. Comparative Example 3, by replacing wood fibers with sepiolite fibers, showed a decrease in performance indicators, which may be due to the difference in fiber type leading to different dispersion states in the system and different overlap structures with attapulgite.

[0115] As shown in Examples 1, 4, 5 and Comparative Examples 8-10, Example 5, using N-tris(hydroxymethyl)methyl-citrate monomethyl hydrazide amide as a wetting and dispersing agent, exhibits significantly improved anti-sagging properties, thixotropic index, and scrub resistance compared to Example 1 using sorbitan monolaurate and Example 4 using N,N-bis(2-hydroxypropyl)-dodecanoamide, and its ethanol resistance is also significantly enhanced. In Comparative Example 8, the wetting and dispersing agent uses an ethanolamine segment instead of the tris(hydroxymethyl)aminomethane fragment from Example 5. The reduction in the number of terminal hydroxyl groups may weaken the interfacial bonding strength between the dispersant and the resin matrix, thus affecting the density and cohesiveness of the coating film. In Comparative Example 9, the wetting and dispersing agent uses glucosamine instead of the tris(hydroxymethyl)aminomethane fragment from Example 5. The introduction of the rigid cyclic structure of glucosamine may restrict the movement of molecular chains to some extent, which is not conducive to establishing a uniform physical cross-linking network in the coating system. Comparative Example 10 uses a physical mixing method to prepare a dispersant, and its adhesion grade drops to level 1, with a significant decrease in water resistance and abrasion resistance. This indicates that the N-tris(hydroxymethyl)methyl-citrate monohydrazide amide used in Example 5 can more effectively promote the dispersion of pigments and fillers and enhance the cohesion of the coating.

[0116] As can be seen from Examples 1, 6, 7 and Comparative Examples 4-7, regarding the thickener, Examples 6 and 7 used associative polyurethanes with specific carbon chain lengths (dodecyl alcohol and tetradecyl alcohol), respectively, which improved the thixotropic index and anti-sagging properties compared to the commercially available product used in Example 1. Comparative Example 4 used n-octanol for end-capping, resulting in shorter hydrophobic segments and relatively lower anti-sagging and thixotropic index of the coating. Comparative Examples 6 and 7 changed the type of chain extender, and their thixotropic index and scrub resistance were lower than those of Example 6, with a significant loss in abrasion resistance. This indicates that the thickeners used in Examples 6 and 7 are more conducive to establishing a balanced hydrophobic associative network in the system. Comparative Example 6 used difunctional 1,6-hexanediol instead of trifunctional trimethylolpropane, and the synthesized thickener had a linear structure, which could not form an effective three-dimensional network, resulting in a significant decrease in the thixotropic index and anti-sagging properties of the coating. Comparative Example 7 uses pentaerythritol with tetrafunctionality. Although it introduces a higher degree of branching, its overly rigid core structure may restrict the flexible movement of hydrophobic end groups, which is not conducive to the formation of a dynamically reversible hydrophobic association network, and also leads to a decrease in performance.

[0117] As can be seen from Examples 8 and 9, the wetting and dispersing agent used in Example 5 and the associative thickener used in Examples 6 and 7 were combined in Examples 8 and 9, which further improved the performance of the coating. This shows that the above-mentioned specific dispersant and thickener have good compatibility and synergistic effect, which together improve the storage stability, anti-sagging properties and physicochemical resistance of the coating.

[0118] In summary, by combining the components, especially by using wetting and dispersing agents and associative thickeners with specific structures, this invention can produce wall painting coatings with good adhesion, good anti-sagging application performance, washability, durability, and resistance to chemical corrosion.

Claims

1. A paint for wall painting, characterized in that, The product is composed of the following components in parts by weight: 35-45 parts of waterborne acrylic copolymer emulsion; 15-25 parts of waterborne iron oxide red paste; 1.8-2.5 parts of silane-modified attapulgite; 0.4-0.6 parts of associative polyurethane thickener; 0.6-1.0 parts of wood fiber; 0.8-1.2 parts of wetting and dispersing agent; 0.15-0.2 parts of defoamer; 2.0-3.0 parts of film-forming aid; and 31-33 parts of water. The preparation method of the silane-modified attapulgite is as follows: attapulgite ore powder and hydrochloric acid are mixed at 60-70°C. After 2-3 hours, acid-activated attapulgite is obtained. Then, the acid-activated attapulgite is dispersed in a solvent, and the pH is adjusted to 4.0-5.

0. γ-aminopropyltriethoxysilane is added, and the mixture is reacted at 70-75°C for 4-5 hours to obtain silane-modified attapulgite. The wetting and dispersing agent is sorbitan monolaurate, N,N-bis(2-hydroxypropyl)-dodecanoamide, or N-tris(hydroxymethyl)methyl-citrate monohydrazide amide. The chemical structure of N-tris(hydroxymethyl)methyl-citrate monohydrazide amide is as follows: 。 2. The wall painting coating as described in claim 1, characterized in that, The attapulgite ore powder has an average diameter of 20-50 nm, an average length of 0.5-2 μm, and a cation exchange capacity of 25-35 mmol / 100g.

3. The wall painting coating as described in claim 1, characterized in that, The concentration of the hydrochloric acid is 2-3 mol / L, and the mass ratio of γ-aminopropyltriethoxysilane to acid-activated attapulgite is 7.5-9:

50.

4. The wall painting coating as described in claim 1, characterized in that, The particle size of the silane-modified attapulgite is greater than 800 mesh.

5. The wall painting coating as described in claim 1, characterized in that, The average length of the wood fibers is 180~220μm, and the average diameter is 10~20μm.

6. The wall painting coating as described in claim 1, characterized in that, The method for preparing the wood fiber is as follows: bleached wood pulp with α-cellulose content ≥90% and kappa number ≤1.0 is dissociated, dried, and then screened to obtain the fiber.

7. The wall painting coating as described in claim 1, characterized in that, The aqueous acrylic copolymer emulsion is prepared by emulsion polymerization of monomers including styrene, hexyl acrylate, methyl methacrylate, acrylic acid and N-hydroxymethylacrylamide.

8. The wall painting coating as described in claim 1, characterized in that, The preparation method of the aqueous acrylic copolymer emulsion includes the following steps: (1) Styrene, hexyl acrylate, methyl methacrylate, acrylic acid and N-hydroxymethylacrylamide are added to a mixture composed of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether, sodium bicarbonate and water, and mixed evenly to obtain a monomer pre-emulsion; the mass ratio of styrene, hexyl acrylate, methyl methacrylate, acrylic acid, N-hydroxymethylacrylamide, sodium dodecyl sulfate, nonylphenol polyoxyethylene ether, sodium bicarbonate and water is 28~30:23~25:7~9:1~2:1.8~3:0.7~1:0.7~1:0.2~0.5:13.5~15; (2) After mixing the monomer preemulsion, ammonium persulfate and water, heat to 80~85℃ and react for 30~45 min to obtain seed emulsion; the mass ratio of the monomer preemulsion, ammonium persulfate and water is 7~10:0.1~0.3:31.5~35; (3) Add the monomer pre-emulsion and ammonium persulfate solution dropwise to the seed emulsion, control the system temperature at 83~87℃, raise the temperature to 88~90℃ after the addition is complete, mix and react for 1~2h, cool down and adjust the pH to 7.0~8.0 to obtain an aqueous acrylic copolymer emulsion; the mass fraction of the ammonium persulfate solution is 7~9%, and the mass ratio of ammonium persulfate in the monomer pre-emulsion, seed emulsion and ammonium persulfate solution is 55~58:35~45:0.25~0.

5.

9. The wall painting coating as described in claim 1, characterized in that, The preparation method of the associative polyurethane thickener includes the following steps: under the action of a catalyst, isophorone diisocyanate, polyethylene glycol PEG-6000 and trimethylolpropane are mixed and reacted, then dimethylolpropionic acid is added for chain extension reaction, and finally a monohydric alcohol compound is added for end capping. After neutralization and dispersion with water, the product is obtained. The molar ratio of isophorone diisocyanate, polyethylene glycol PEG-6000, trimethylolpropane, dimethylolpropionic acid and monohydric alcohol compound is 0.11~0.13:0.01~0.015:0.01~0.015:0.06~0.07:0.05~0.

06. The monohydric alcohol compound is n-dodecyl alcohol or n-tetradecyl alcohol.

10. A method for preparing a wall painting coating as described in any one of claims 1-9, characterized in that, The process includes the following steps: mixing the formulated amounts of waterborne acrylic copolymer emulsion, waterborne iron oxide red paste, silane-modified attapulgite, associative polyurethane thickener, wood fiber, wetting and dispersing agent, defoamer, film-forming aid, and water evenly to obtain the final product.

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