An aqueous resin for wall hardener and its preparation method

Abstract

The present invention belongs to the technical field of wall coatings, and particularly relates to an aqueous resin for wall curing agents and a preparation method thereof. Specifically, the following raw materials are included: polyurethane prepolymer, acrylic resin, aminated lignin, epoxy-functionalized nano-SiO2 particles, polyamide, surfactant, catalyst. During the preparation process, the epoxy-functionalized nano-SiO2 particles and aminated lignin of the present invention are first mixed and then reacted with the polyurethane prepolymer, greatly improving the adhesion and structural strength of the resin material. At the same time, the reaction with polyamide further improves the adhesion and toughness of the composite resin; moreover, the cross-linking reaction between the acrylic resin and the polyurethane can form a stable network structure, which can effectively isolate the influence of the external environment, reduce the attachment of pollutants, and resist the invasion of ultraviolet rays and moisture, significantly enhancing the adhesion, abrasion resistance, weather resistance and stain resistance of the resin material.

Description

Technical Field

[0001] The present invention belongs to the technical field of wall coatings, and particularly relates to an aqueous resin for wall curing agents and a preparation method thereof. Background Art

[0002] In the field of wall materials, existing curing agents are mainly used to enhance the adhesion, abrasion resistance and weather resistance of coatings. However, in actual applications, the performance in these aspects still has deficiencies, especially in extreme environments or during long-term use. For example, on some smooth or low-absorbency substrates, the coating of existing wall curing agents is prone to peeling or falling off; especially in humid or dusty environments, the coating formed after curing is very easy to bulge or peel off. Therefore, it is urgent to improve the general adhesion of the curing agent on different substrates and its durability in special environments. Secondly, in special application scenarios such as public buildings and industrial factories, the walls may be subject to frequent friction, collision and scratching, and the coating is also easily damaged, resulting in the wall losing its protective layer, thereby affecting its aesthetics and service life. Moreover, when existing wall curing agents are used outdoors, since they are long-term exposed to sunlight, rain, sand and large temperature changes, the coating is prone to problems such as aging, cracking and fading, which not only affects the appearance of the wall, but also reduces the functionality of the coating, such as waterproof, mildew-proof and anti-fouling properties. In summary, there is still a large room for improvement in the adhesion, abrasion resistance, weather resistance and anti-fouling properties of existing wall curing agents. Therefore, there is an urgent need for new resin materials to improve the performance of wall curing agents.

[0003] For example, Chinese Patent CN107629627B discloses a permeable hydrophobic multifunctional new waterproof coating and its preparation method and application. The permeable hydrophobic multifunctional new waterproof coating comprises the following components in parts by weight: film-forming substance 30-45 parts, permeable waterproof hydrophobic raw material 4-8 parts, auxiliary agent 0.3-0.6 part, permeable rust inhibitor 0.5-2 parts, pigment in an appropriate amount, thickener 1-6 parts, active diluent 1-12 parts, toughening agent 3-6 parts, filler 30-45 parts, and the usage amount of spiroamine curing agent is 30%-50% of the weight of the film-forming substance. This waterproof coating has a high bonding strength with concrete and a large hydrophobic angle, and has a strong reinforcing and waterproof effect, especially suitable for concrete floors and walls with poor structural strength. However, the adhesion of this coating is greatly affected by environmental conditions (such as humidity and temperature). Especially in high-humidity or high-temperature environments, the adhesion will decrease; moreover, the film-forming substance has insufficient resistance to ultraviolet rays. When exposed to sunlight for a long time, the coating will fade, powder or crack, reducing the weather resistance. In summary, although this waterproof coating performs well in some aspects, there are still certain defects in adhesion, weather resistance and anti-fouling properties. Therefore, the present invention provides an aqueous resin for wall curing agents and a preparation method thereof in order to solve the above technical problems. Summary of the Invention

[0004] To solve the problems existing in the prior art, the object of the present invention is to provide an aqueous resin for wall curing agent and a preparation method thereof. During the preparation of the aqueous resin for wall curing agent, the epoxidized nano-SiO2 particles are first mixed with amino-functionalized lignin, and the amino and epoxy groups react with the isocyanate groups in the polyurethane prepolymer, thereby improving the adhesion and structural strength of the resin material; at the same time, the introduction of the epoxidized nano-SiO2 particles in the present invention not only slows down the degradation process of lignin, but also enhances the hardness, heat resistance and wear resistance of the resin material, making the resin for curing agent more durable in daily use; subsequently, acrylic resin is added and crosslinked with polyurethane to form a stable network structure, effectively isolating the influence of the external environment, reducing the attachment of pollutants, and resisting the invasion of ultraviolet rays and moisture, thereby significantly improving the adhesion, wear resistance, weather resistance and stain resistance of the resin material.

[0005] An aqueous resin for wall curing agent, comprising the following raw materials in parts by weight: 200-215 parts of polyurethane prepolymer, 100-110 parts of acrylic resin, 30-35 parts of amino-functionalized lignin, 30-35 parts of epoxidized nano-SiO2 particles, 10-15 parts of polyamide, 5-6 parts of surfactant, 3-5 parts of catalyst.

[0006] A large number of hydrogen bonds can be formed between the amino groups (-NH) contained in the polyurethane prepolymer of the present invention and the carboxyl groups (-COOH) in the acrylic resin, which can effectively enhance the binding force between the two. Moreover, during the polymerization process, the double bonds (-C=C) of the acrylic resin can undergo a ring-opening reaction with the hydroxyl groups (-OH) in the polyurethane to form new covalent linkages. Therefore, when the two resins are mixed, the formation of the above-mentioned hydrogen bonds and covalent bonds causes the molecular chains to crosslink with each other, forming a complex three-dimensional network structure, which provides excellent flexibility, adhesion, weather resistance, and ultraviolet resistance for the system. And this crosslinked structure can effectively disperse stress and improve the mechanical properties of the overall resin material. Secondly, as a natural polymer resin material, the polymerized structure and flexible molecular chains of amino-functionalized lignin can assist in forming a more flexible network after the resin is cured. Moreover, the phenolic hydroxyl groups (-OH) in amino-functionalized lignin can form hydrogen bonds with the polyurethane and acrylic resin, further enhancing the adhesion and toughness of the resin material and preventing the formation of tiny surface cracks, thereby reducing the possibility of dirt entering these microcracks. Therefore, introducing it into the resin used in the wall curing agent can effectively increase the toughness and elasticity of the resin, thereby improving the impact resistance of the resin material, and at the same time enhancing the eco-friendliness of the resin material. Furthermore, the present invention also adds polyamide as a raw material, and its amide groups (-CONH-) can form hydrogen bonds with the polyurethane and acrylic resin to enhance the adhesion and toughness of the resin material. At the same time, its combination with amino-functionalized lignin can form a composite phase in the resin, enabling the applied external stress to be effectively dispersed inside the resin material, preventing local overload and reducing the risk of cracking. And the surface properties of this composite resin material are significantly improved due to the hydrophobicity of lignin and the wear resistance of polyamide, and a more uniform composite structure can be formed, so that the surface of the final coating is smoother, effectively preventing dirt adhesion and avoiding the penetration of dirt on the surface and inside, improving the cleanliness.

[0007] Furthermore, since lignin will exhibit certain performance degradation under conditions of high temperature, humidity, or strong chemical corrosion, the present invention has carried out a modification treatment on lignin and, at the same time, combined it with raw materials such as modified epoxy nanosilica particles, significantly reducing the degradation rate of lignin in a humid environment. Through the amination reaction, the present invention introduces amino (-NH2) functional groups on the surface of lignin, improving its compatibility with other components such as modified nanosilica particles and resins. And the aminated lignin can form chemical crosslinks with the polyurethane and acrylic resin, and the enhanced compatibility can improve the stability of lignin in the composite resin material and slow down its degradation in an environment of high temperature, humidity, or strong chemical corrosion.

[0008] Further, the preparation of the aminated lignin includes: dissolving lignin in ethanol, adding ethylenediamine, stirring and heating to 60 - 65 °C for reaction for 4 - 6 h. After the reaction, washing the lignin product with distilled water, centrifuging and drying to obtain aminated lignin for standby.

[0009] The above-mentioned ethylenediamine reacts with the hydroxyl groups of lignin to form aminated lignin, enhancing the interaction between lignin with amino (-NH2) functional groups and modified epoxy nanosilica particles and resin. The reaction between amino and epoxy groups forms more stable chemical bonds, effectively improving the performance of lignin in the composite resin material. At the same time, the chemical interaction and physical crosslinking between epoxy nanosilica particles and aminated lignin also significantly enhance the adhesion of the resin material to the wall substrate. Moreover, epoxy groups can form a protective film in the resin to block the active sites of lignin, further slowing down its degradation in a strong chemical corrosion environment. And the combined use of epoxy nanosilica particles and polyurethane can effectively improve the stability of the resin material at high temperatures and slow down the thermal degradation of lignin.

[0010] Further, the mass ratio of the lignin to ethylenediamine is (3 - 7):(1 - 2).

[0011] Further, the preparation of the epoxy nanosilica particles includes: dispersing the nanosilica particles in an ethanol solution, stirring and ultrasonically dispersing; then adding 3-aminopropyltriethoxysilane and stirring at room temperature for reaction for 3.5 - 4.5 h. After the reaction, centrifuging the product and washing with ethanol, drying for standby to obtain amino-modified nanosilica particles; then redispersing the dried amino-modified nanosilica particles in an ethanol solution, and adding epichlorohydrin, stirring and reacting at 55 - 65 °C for 4 - 6 h. After the reaction, centrifuging, washing with ethanol, and drying to obtain epoxy nanosilica particles.

[0012] In the above reaction, 3-aminopropyltriethoxysilane (APTES) undergoes a chemical reaction through its amino group with the hydroxyl groups on the surface of pretreated nano-SiO2 particles to form amino-modified SiO2. This process generates a silicon-oxygen bond (Si-O) chemical bond, which enhances the adhesion between nano-SiO2 and the resin matrix. Subsequently, epichlorohydrin (EPC) reacts with the surface of the amino-modified SiO2 particles to form the grafting of epoxy groups. This grafting provides additional reaction sites, enabling the modified nano-SiO2 to crosslink better with polyurethane and acrylic resins. Finally, the reaction of epoxy groups with active groups such as amino or hydroxyl groups will form strong chemical bonds (such as ether bonds, etc.), further improving the adhesion and durability. Moreover, the addition of the epoxidized nano-SiO2 particles in the present invention improves the overall waterproof performance and heat resistance of the resin material. At the same time, the epoxidized nano-SiO2 particles can form a dense network structure in the resin, reducing the penetration of moisture, thereby significantly reducing the degradation rate of lignin in a humid and high-temperature environment.

[0013] Furthermore, the dosage ratio of the nano-SiO2 particles, 3-aminopropyltriethoxysilane, and epichlorohydrin is (5 - 7) g : (1 - 2) g : (3 - 4) mL.

[0014] Furthermore, the surfactant is cetyltrimethylammonium bromide; the catalyst is triethanolamine.

[0015] Moreover, the present invention also provides a preparation method of the aqueous resin for the wall curing agent as described above, including: adding the epoxidized nano-SiO2 particles and amino-modified lignin into an ethanol solvent for mixing, followed by ultrasonic dispersion and drying to obtain a mixture; then, at 60 °C, mixing the polyurethane prepolymer with the above mixture and stirring for 1.5 - 2 h; adding the acrylic resin and continuing to stir for 10 - 30 min; adding polyamide and stirring for 25 - 35 min; adding the surfactant and stirring for 10 - 15 min; finally, adding the catalyst for catalysis and stirring for 15 - 30 min, standing for 0.5 - 1.5 h to obtain the aqueous resin for the wall curing agent. After removing bubbles, it is sub-packed into sealed containers.

[0016] In the process of mixing epoxy-functionalized nano-SiO2 particles with aminated lignin, the amino and epoxy groups therein can react with the isocyanate groups in the polyurethane prepolymer to form strong urea or urethane bonds, which helps to improve the adhesion and structural strength of the resin material. Moreover, the introduction of epoxy-functionalized nano-SiO2 particles enhances the hardness, heat resistance and wear resistance of the resin material, making the resin for curing agent more durable in daily use. Subsequently, the introduction of acrylic resin can react with polyurethane to form a crosslinked structure, and a more stable network structure can be formed through polymerization reaction, thus effectively isolating the influence of the external environment, reducing the adhesion of pollutants, and resisting the invasion of ultraviolet rays and moisture, thereby improving the wear resistance, stain resistance and weather resistance of the resin material. In summary, the composite resin prepared by the present invention significantly improves the performance of the wall curing agent under various harsh conditions through a series of chemical reactions and crosslinking reactions, and solves the deficiencies of the existing resin materials for curing agents.

[0017] Further, the stirring speed is 400 - 700 revolutions per minute.

[0018] Secondly, the present invention also provides the use of the aqueous resin for wall curing agent as described above in the preparation of wall curing agent.

[0019] Compared with the prior art, the aqueous resin for wall curing agent and its preparation method provided by the present invention have the following advantages:

[0020] The composite resin of the present invention significantly improves the flexibility, adhesion, weather resistance, and stain resistance of the resin material by constructing a complex three-dimensional network structure. Among them, the interaction between the amino group (-NH) in the polyurethane prepolymer and the carboxyl group (-COOH) in the acrylic resin, combined with the ring-opening reaction of the double bond (-C=C) in the acrylic resin and the hydroxyl group (-OH) of the polyurethane, ensures the effective cross-linking of the molecular chains, thereby enhancing the overall mechanical properties of the resin material; to enhance the ecological friendliness and toughness of the resin material, amino-functionalized lignin is introduced as a natural polymer resin material in the present invention. The hydrogen bonds formed between its phenolic hydroxyl group (-OH) and the resin not only improve the flexibility of the resin material but also significantly reduce the formation of microcracks. At the same time, in order to improve the stability of lignin in high-temperature, humid, and chemically corrosive environments, the present invention modifies lignin and combines it with modified epoxy nano-SiO2 particles, effectively improving the durability of lignin and its compatibility with other raw materials, making the surface of the final resin coating smoother and greatly enhancing the cleanliness of the resin for wall curing agents; in addition, the present invention also introduces polyamide to further improve the adhesion and toughness of the composite resin material. The amide group (-CONH-) in polyamide can form hydrogen bonds with polyurethane and acrylic resin, promoting the effective dispersion of stress and reducing the risk of cracking; the modified epoxy nano-SiO2 particles are modified with amino groups to provide additional reaction sites, thereby improving the heat resistance, waterproof performance, and overall wear resistance of the resin, ensuring the excellent performance of the resin material under harsh conditions. Description of the Drawings

[0021] Figure 1 is the aqueous resin for wall curing agent prepared in Example 3;

[0022] Figure 2 is the aqueous resin for wall curing agent prepared in Example 2. Detailed Embodiments

[0023] The present invention will be further described below through the description of specific embodiments, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements according to the basic idea of the present invention, but as long as they do not depart from the basic idea of the present invention, they are within the protection scope of the present invention.

[0024] In the following examples and comparative examples, the methods used, unless otherwise specified, are all prior arts; the reagents not specifically described are conventional reagents, which can be purchased from conventional reagent production and sales companies. Information such as the production manufacturers and CAS numbers of some raw materials is as follows:

[0025] The polyurethane prepolymer was purchased from Zibo Qishang Network Technology Co., Ltd.;

[0026] Acrylic resin, purchased from Changzhou Gene New Resin Materials Co., Ltd., grade JE-6132;

[0027] Lignin, CAS number is 8068-05-1;

[0028] Ethylenediamine, CAS number is 107-15-3;

[0029] 3-Aminopropyltriethoxysilane, CAS number is 919-30-2;

[0030] Epichlorohydrin, CAS number is 106-89-8;

[0031] Polyamide, CAS number is 63428-84-2, purchased from Zhenjiang Danbao Resin Co., Ltd.;

[0032] Cetyltrimethylammonium bromide, CAS number is 57-09-0;

[0033] Triethanolamine, CAS number is 102-71-6.

[0034] Example 1

[0035] (1) Preparation method of amino-functionalized lignin: Dissolve 300 g of lignin in 2500 mL of ethanol, add 100 g of ethylenediamine, stir and heat to 60 °C for reaction for 4 h. After the reaction, wash the lignin product 3 times with distilled water, centrifuge and dry to obtain amino-functionalized lignin.

[0036] (2) Preparation method of epoxidized nano-SiO2 particles:

[0037] Step ① Disperse 500 g of nano-SiO2 particles in a 50% ethanol solution, stir and ultrasonically disperse; then add 100 g of 3-aminopropyltriethoxysilane, stir and react at room temperature for 3.5 h. After the reaction, centrifuge the product and wash with ethanol, then dry to obtain amino-modified nano-SiO2 particles;

[0038] Step ② Redisperse the amino-modified nano-SiO2 particles prepared in Step ① in a 50% ethanol solution, then add 300 mL of epichlorohydrin, stir and react at 55 °C for 4 h. After the reaction, centrifuge, wash 3 times with ethanol, and dry to obtain epoxidized nano-SiO2 particles.

[0039] (3) Preparation method of waterborne resin for wall curing agent:

[0040] 300 g of epoxy-functionalized nano-SiO₂ particles and 300 g of amino-functionalized lignin were added to an ethanol solvent and mixed. After ultrasonic dispersion and drying, a mixture was obtained. Then, at 60 °C, 2000 g of polyurethane prepolymer was mixed with the above mixture and stirred at a speed of 400 rpm for 1.5 h. Then, 1000 g of acrylic resin was added and stirring continued for 10 min. 100 g of polyamide was added and stirring continued for 25 min. 50 g of cetyltrimethylammonium bromide was added and stirring continued for 10 min. Finally, 30 g of triethanolamine was added as a catalyst and stirring continued for 15 min. After standing for 0.5 h, an aqueous resin for wall curing agent was obtained. After removing air bubbles, it was dispensed into sealed containers.

[0041] Example 2

[0042] (1) Preparation method of amino-functionalized lignin: 700 g of lignin was dissolved in 2500 mL of ethanol, 200 g of ethylenediamine was added, and the mixture was stirred and heated to 65 °C for reaction for 6 h. After the reaction ended, the lignin product was washed 3 times with distilled water, centrifuged and dried to obtain amino-functionalized lignin.

[0043] (2) Preparation method of epoxy-functionalized nano-SiO₂ particles:

[0044] Step ①: 700 g of nano-SiO₂ particles were dispersed in a 50% ethanol solution, stirred and ultrasonically dispersed. Then, 200 g of 3-aminopropyltriethoxysilane was added, and the mixture was stirred at room temperature for 4.5 h. After the reaction ended, the product was centrifuged and washed with ethanol, and then dried to obtain amino-modified nano-SiO₂ particles.

[0045] Step ②: The amino-modified nano-SiO₂ particles prepared in Step ① were redispersed in a 50% ethanol solution, and then 400 mL of epichlorohydrin was added. The mixture was stirred at 65 °C for reaction for 6 h. After the reaction ended, it was centrifuged, washed 3 times with ethanol, and dried to obtain epoxy-functionalized nano-SiO₂ particles.

[0046] (3) Preparation method of aqueous resin for wall curing agent:

[0047] 350 g of epoxy-functionalized nano-SiO₂ particles and 350 g of amino-functionalized lignin were added to an ethanol solvent and mixed. After ultrasonic dispersion and drying, a mixture was obtained. Then, at 60 °C, 2150 g of polyurethane prepolymer was mixed with the above mixture and stirred at a speed of 700 rpm for 2 h. Then, 1100 g of acrylic resin was added and stirring continued for 30 min. 150 g of polyamide was added and stirring continued for 35 min. 60 g of cetyltrimethylammonium bromide was added and stirring continued for 15 min. Finally, 50 g of triethanolamine was added as a catalyst and stirring continued for 15 - 30 min. After standing for 1.5 h, an aqueous resin for wall curing agent was obtained. After removing air bubbles, it was dispensed into sealed containers.

[0048] Example 3

[0049] (1) Preparation method of aminated lignin: Dissolve 500 g of lignin in 2500 mL of ethanol, add 150 g of ethylenediamine, stir and heat to 60 °C for reaction for 5 h. After the reaction, wash the lignin product with distilled water 3 times, centrifuge and dry to obtain aminated lignin.

[0050] (2) Preparation method of epoxidized nano-SiO₂ particles:

[0051] Step ①: Disperse 600 g of nano-SiO₂ particles in a 50% ethanol solution, stir and ultrasonically disperse; then add 150 g of 3-aminopropyltriethoxysilane, stir and react at room temperature for 4 h. After the reaction, centrifuge the product and wash with ethanol, then dry to obtain amino-modified nano-SiO₂ particles;

[0052] Step ②: Redisperse the amino-modified nano-SiO₂ particles prepared in Step ① in a 50% ethanol solution, then add 350 mL of epichlorohydrin, stir and react at 60 °C for 5 h. After the reaction, centrifuge, wash with ethanol 3 times, and dry to obtain epoxidized nano-SiO₂ particles.

[0053] (3) Preparation method of water-based resin for wall curing agent:

[0054] Mix 350 g of epoxidized nano-SiO₂ particles and 300 g of aminated lignin in an ethanol solvent, ultrasonically disperse and dry to obtain a mixture; then at 60 °C, mix 2100 g of polyurethane prepolymer with the above mixture, stir at a speed of 500 r / min for 2 h; then add 1100 g of acrylic resin and continue to stir for 20 min; add 150 g of polyamide and continuously stir for 30 min; add 55 g of cetyltrimethylammonium bromide and then stir for 15 min; finally add 40 g of triethanolamine for catalysis and stir for another 20 min, let stand for 1 h to obtain water-based resin for wall curing agent. After removing air bubbles, sub-pack into sealed containers.

[0055] Comparative Example 1

[0056] The difference from Example 3 is that aminated lignin is not added in Comparative Example 1, and other steps and preparation processes are the same as those in Example 3.

[0057] Comparative Example 2

[0058] The difference from Example 3 is that lignin is not modified in Comparative Example 2, and other steps and preparation processes are the same as those in Example 3.

[0059] Comparative Example 3

[0060] The difference from Example 3 is that epoxidized nano-SiO2 particles were not added in Comparative Example 3, and other steps and preparation processes were the same as those in Example 3.

[0061] Comparative Example 4

[0062] The difference from Example 3 is that the nano-SiO2 particles were not modified in Comparative Example 4, and other steps and preparation processes were the same as those in Example 3.

[0063] Comparative Example 5

[0064] The difference from Example 3 is that polyamide was not added in Comparative Example 5, and other steps and preparation processes were the same as those in Example 3.

[0065] Comparative Example 6

[0066] The difference from Example 3 is that the amount of polyurethane prepolymer in Comparative Example 6 was 1100 g, and other steps and preparation processes were the same as those in Example 3.

[0067] Test Example: Performance Test

[0068] 1. Test resin material: The waterborne resin for wall curing agent prepared in the examples and comparative examples of the present invention.

[0069] 2. Test method:

[0070] (1) Test the stain resistance of the sample according to GB / T9780-2013 "Test Method for Stain Resistance of Building Paint Coatings";

[0071] (2) Test the cross-cut adhesion of the sample according to GB / T9286-1998 "Cross-Cut Test for Paint and Varnish Films";

[0072] (3) Test the flexibility of the sample according to GB / T1731-2020 "Determination of Flexibility of Paint Films and Putty Films";

[0073] (4) Test the impact resistance of the sample according to GB / T1732-2020 "Determination of Impact Resistance of Paint Films";

[0074] (5) Test the water resistance of the sample according to GB / T1733-1993 "Determination of Water Resistance of Paint Films";

[0075] (6) Test the 1000-hour salt spray resistance of the sample according to GB / T1771-2007 "Determination of Resistance to Neutral Salt Spray of Paints and Varnishes";

[0076] (7) Test the pencil hardness of the sample according to GB / T6739-2006 "Determination of Film Hardness by Pencil Method for Paints and Varnishes".

[0077] The test results are shown in Table 1 and Table 2

[0078] Table 1 Performance test results of the embodiments of the present invention

[0079]

[0080] Table 2 Performance test results of the comparative examples of the present invention

[0081]

[0082] As shown in the above test results, all the performance test results of the aqueous resin for wall curing agent obtained in the embodiments of the present invention are excellent. When the raw materials and preparation parameters in the preparation process of the present invention are changed in each group of comparative examples, the performance of the prepared resin materials is affected to varying degrees.

[0083] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A water-based resin for a wall curing agent, characterized in that: The invention comprises the following raw materials in parts by weight: 200-215 parts of polyurethane prepolymer, 100-110 parts of acrylic resin, 30-35 parts of amino lignin, 30-35 parts of epoxidized nano-SiO2 particles, 10-15 parts of polyamide, 5-6 parts of surfactant, and 3-5 parts of catalyst; The preparation of the amino lignin comprises: dissolving lignin in ethanol, adding ethylenediamine, stirring and heating to 60-65° C. for reaction for 4-6 hours, and after the reaction, washing the lignin product with distilled water, centrifuging and drying to obtain the amino lignin; The preparation of the epoxidized nano-SiO2 particles comprises: Step ① Disperse nano-SiO2 particles in an ethanol solution, stir and disperse by ultrasound; then add 3-aminopropyltriethoxysilane, stir and react at room temperature for 3.5-4.5 hours. After the reaction is completed, centrifuge and separate the product, wash it with ethanol, and dry it to obtain amino-modified nano-SiO2 particles; Step ②: Re-disperse the amino-modified nano-SiO2 particles in an ethanol solution, then add epichlorohydrin, stir and react at 55-65°C for 4-6 hours, and after the reaction is completed, centrifuge, wash with ethanol, and dry to obtain epoxidized nano-SiO2 particles; The mass ratio of lignin to ethylenediamine is (3-7): (1-2); The dosage ratio of the nano-SiO2 particles to 3-aminopropyltriethoxysilane and epichlorohydrin is (5-7) g: (1-2) g: (3-4) mL.

2. The water-based resin for wall curing agent according to claim 1, characterized in that: The surfactant is hexadecyltrimethylammonium bromide; and the catalyst is triethanolamine.

3. The method for preparing the aqueous resin for a wall curing agent according to claim 1 or 2, characterized in that: include: The epoxidized nano-SiO2 particles and the amino lignin are added to an ethanol solvent, mixed, ultrasonically dispersed, and dried to obtain a mixture; then, the polyurethane prepolymer is mixed with the mixture at 60°C and stirred for 1.5-2 h; then, acrylic resin is added and stirring is continued for 10-30 min; polyamide is added and stirring is continued for 25-35 min; a surfactant is added and stirring is continued for 10-15 min; finally, a catalyst is added and stirred for 15-30 min, and the mixture is allowed to stand for 0.5-1.5 h to obtain a water-based resin for a wall curing agent, and after eliminating bubbles, it is dispensed into sealed containers.

4. The method for preparing the water-based resin for wall curing agent according to claim 3, characterized in that: The stirring speed is 400-700 rpm.

5. Use of the aqueous resin for wall curing agent as claimed in claim 1 or 2 in the preparation of wall curing agent.

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