Adaptive environment-friendly putty-free coating and preparation method thereof

Abstract

The invention relates to the field of coating preparation, in particular to adaptive environment-friendly putty-free coating and a preparation method thereof. The coating comprises a film-forming agent, nano silicon dioxide, a functional additive and deionized water, the film-forming agent comprises a hybrid emulsion and a supramolecular quadruple hydrogen bond monomer; the hybrid emulsion is formed by copolymerization of acrylate containing disulfide bonds and organic silicon; the functional additive comprises any one or more of hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and polyether modified silicone oil. A double-network interpenetrating structure is formed by the acrylic acid-organic silicon hybrid emulsion containing the disulfide bond and the supramolecular quadruple hydrogen bond monomer, the disulfide bond endows the coating with self-repairing ability, and the quadruple hydrogen bond improves the film-forming property and adhesive force of the coating. And nano silicon dioxide enhances hardness and alkali resistance. In the functional additive, hyperbranched polyglycerol ester improves the rheological property, phosphorylated bamboo fiber nanocrystals and silicon dioxide form multi-stage filling to improve the environmental protection property of the coating, and a defoaming system improves the uniformity of the coating.

Description

Technical Field

[0001] This application relates to the field of coating preparation technology, specifically to an adaptive, environmentally friendly, putty-free coating and its preparation method. Background Technology

[0002] In the field of architectural decoration, traditional coating processes rely on putty layers for leveling, which presents three major technical bottlenecks: First, the construction is cumbersome, requiring multiple scraping and sanding processes, which is time-consuming, labor-intensive, and has high labor costs; second, there are significant environmental risks, as putty often contains volatile organic compounds (VOCs) such as formaldehyde and benzene series compounds, as well as harmful substances such as asbestos and lead, which endanger human health; third, performance is limited, with existing putty-free coatings generally suffering from poor substrate adaptability (such as reduced adhesion due to alkaline erosion of cement substrates), insufficient weather resistance (prone to powdering and cracking under long-term ultraviolet radiation), and low defoaming efficiency (foam during production and construction affects the uniformity of the coating film).

[0003] In the prior art, Chinese patent application CN116376376A discloses a putty-free textured coating and its application method. However, its film-forming system uses only ordinary acrylic emulsion, failing to address the issue of coating stability under complex environments. Ordinary acrylic emulsions lack dynamic repair capabilities after film formation, making them prone to irreversible cracking under temperature changes or mechanical stress. While simple silicone-modified coatings can improve weather resistance, the physical blending method results in insufficient cohesive strength, making it difficult to balance high hardness and flexibility.

[0004] Therefore, there is a significant practical need to develop a new type of coating that is putty-free and has improved adhesion, weather resistance, crack prevention, and environmental performance. Summary of the Invention

[0005] To address the above technical issues, this application provides an adaptive and environmentally friendly putty-free coating and its preparation method. A film-forming agent is formed by copolymerizing an acrylic-organosilicon hybrid emulsion containing disulfide bonds with a supramolecular four-fold hydrogen bond monomer, thereby improving the coating's adhesion and crack resistance. At the same time, nanofillers and functional additives are added to enhance the coating's environmental friendliness.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides an adaptive, environmentally friendly, putty-free coating, comprising a film-forming agent, nano-silica, and functional additives; the film-forming agent comprises a hybrid emulsion and a supramolecular tetrahydrobonded monomer; the hybrid emulsion is copolymerized from disulfide-bonded acrylate and organosilicon; the functional additives comprise hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals, and a leveling agent; the leveling agent is obtained by compounding polyether-modified silicone oil and fluorocarbon surfactant.

[0008] In this application, during the film-forming process, an acrylic-organosilicon hybrid emulsion containing disulfide bonds is prepared through core-shell emulsion polymerization. The core layer consists of acrylate copolymer segments containing hydroxyl and carboxyl polar groups, providing adhesion and initial film-forming properties for the coating. The shell layer consists of polysiloxane segments containing methyl and phenyl hydrophobic groups, imparting weather resistance, low surface energy, and flexibility to the coating. The disulfide bonds in the hybrid emulsion form a dynamic cross-linking network through thiol-disulfide bond exchange reactions. The disulfide bonds (-SS-) serve as reversible cross-linking nodes, enabling stress-responsive self-healing and endowing the coating with reversible repair capabilities. Simultaneously, supramolecular tetrahydrobonded monomers containing uracilone and carboxylic acid groups are introduced. These monomers form physical cross-links with the polar groups of the hybrid emulsion through hydrogen bonds (NH…O, C=O…HO), and chemical cross-link with the disulfide bonds to form a double-network interpenetrating structure, enhancing the cohesive strength and crack resistance of the coating film.

[0009] In this application, the hydroxyl groups on the surface of the filler nano-silica form hydrogen bonds with the polar groups of the film-forming agent, enhancing interfacial compatibility. Simultaneously, its high specific surface area adsorbs alkaline substances from the substrate surface, improving the coating's alkali resistance. Hyperbranched polyglycerol ester, a functional additive prepared by ring-opening polymerization of epichlorohydrin and glycerol, forms a hydrogen bond network with the aqueous phase through its hydroxyl groups, disrupting the stability of the foam liquid film. Introducing phosphate groups (-OPO3H2) into bamboo fiber nanocrystals yields phosphorylated modified bamboo fiber nanocrystals. The negatively charged groups repel the positively charged groups on the foam surface, causing the nanocrystals to adsorb at the gas-liquid interface, reducing film elasticity. Simultaneously, it forms a multi-level "fiber-particle" filling structure with the filler nano-silica, improving the coating's density and environmental friendliness, filling the gaps between polymer molecules, reducing the coating's porosity, and thus increasing its hardness. By compounding polyether-modified silicone oil with fluorocarbon surfactants, the polydimethylsiloxane segments of the polyether-modified silicone oil can reduce interfacial tension, while the polyether segments enhance water solubility; the fluorocarbon surfactants, with their extremely low surface tension, can spread and break bubbles rapidly. The three work together to achieve a dual function of defoaming and foam suppression.

[0010] Preferably, the supramolecular tetrahydrobonded monomer is obtained by reacting 2-amino-4-hydroxy-6-methylpyrimidine with isocyanoethyl methacrylate; the disulfide-containing acrylate is obtained by reacting a hydroxyl-containing acrylate monomer with a disulfide-containing bifunctional compound; the hydroxyl-containing acrylate monomer includes any one of hydroxyethyl methacrylate, hydroxypropyl acrylate, and 2-hydroxyethyl acrylate; the disulfide-containing bifunctional compound includes any one of di(N-hydroxysuccinimide) 3,3'-dithiodipropionate, 3,3'-dithiodioctylpropionamide, and bis(2-carboxyethyl) disulfide; the organosilicon includes any one of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethylsilane.

[0011] Preferably, the hyperbranched polyglycerol ester is obtained by reacting glycerol with epichlorohydrin; the phosphorylated modified bamboo fiber nanocrystals are obtained by reacting bamboo fiber nanocrystals with diammonium hydrogen phosphate; the polyether modified silicone oil is obtained by reacting terminal hydrogen silicone oil with allyl polyoxyethylene ether; and the fluorocarbon surfactant is obtained by reacting perfluorohexylethylene with polyethylene glycol monomethyl ether.

[0012] Preferably, the mass ratio of the film-forming agent, nano-silica, and functional additives is (60-75):(5-15):(10-25); the mass ratio of the disulfide-bonded acrylate, organosilicon, and supramolecular tetrahydrobonded monomer is (60-80):(20-40):1; the mass ratio of the hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals, and leveling agent is (3-5):(2-4):(1-2); and the mass ratio of the polyether-modified silicone oil and fluorocarbon surfactant is (8-12):1.

[0013] Preferably, the mass ratio of the hydroxyl-containing acrylate monomer to the disulfide-containing bifunctional compound is 1:(0.6-1.0); the mass ratio of glycerol to epichlorohydrin is 1:(2.5-4.0); the mass ratio of bamboo fiber nanocrystals to diammonium hydrogen phosphate is 1:(0.3-0.8); the mass ratio of terminal hydrogen silicone oil to allyl polyoxyethylene ether is 1:(0.9-1.2); and the mass ratio of perfluorohexylethylene to polyethylene glycol monomethyl ether is 1:(1.0-1.5).

[0014] Secondly, this application provides a method for preparing an adaptive, environmentally friendly, putty-free coating, comprising the following steps:

[0015] Step 1: Add ethyl acetate and hydroxyl-containing acrylate monomer to a reactor, and heat and stir under nitrogen protection; slowly add a disulfide-bonded bifunctional compound, and after the addition is complete, maintain the temperature and react, then distill under reduced pressure to obtain acrylate containing disulfide bonds; add deionized water, sodium dodecylbenzenesulfonate and half the mass of ammonium persulfate to a reaction vessel, and heat and stir to form an initial emulsion; mix the acrylate monomer containing disulfide bonds with organosilicon, and add it dropwise to the initial emulsion; after the addition is complete, add the remaining mass of ammonium persulfate, maintain the temperature and mature, cool to room temperature and filter to obtain a hybrid emulsion;

[0016] Step 2: Mix glycerol and epichlorohydrin, add calcium hydroxide, and stir to react; after cooling, adjust the pH to 6.5-7.5 with hydrochloric acid, and dry under reduced pressure to obtain hyperbranched polyglycerol ester; mix bamboo fiber nanocrystals and deionized water, add diammonium hydrogen phosphate, and simultaneously add urea, stir to react, centrifuge, wash, and dry to obtain phosphorylated modified bamboo fiber nanocrystals; take terminal hydrogen silicone oil and allyl polyoxyethylene ether, add platinum catalyst, and react under nitrogen protection to obtain polyether modified silicone oil; take perfluorohexylethylene and polyethylene glycol monomethyl ether to react, add azobisisobutyronitrile, and carry out an addition reaction to obtain fluorocarbon surfactant;

[0017] Step 3: Mix and stir the hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and leveling agent to obtain functional additives;

[0018] Step 4: First, react 2-amino-4-hydroxy-6-methylpyrimidine with isocyanate methacrylate to prepare a supramolecular four-fold hydrogen bond monomer. Then, mix nano-silica and deionized water, add silane coupling agent KH570, add the hybrid emulsion and supramolecular four-fold hydrogen bond monomer, and stir. Add the functional additives, add deionized water to a solid content of 40%-60%, and continue stirring. Finally, degas under vacuum and filter to obtain an adaptive environmentally friendly putty-free coating.

[0019] Preferably, in step 1, the mass ratio of ethyl acetate to hydroxyl-containing acrylate monomer is (1.5-3):1; the heating temperature under nitrogen protection is 30-50℃, and the stirring time is 1-2 hours; the reaction time after the addition is 2-4 hours; the mass ratio of deionized water, sodium dodecylbenzenesulfonate, and ammonium persulfate is 100:(2-3):(0.3-0.6); the temperature for heating and stirring to form the initial emulsion is 75-85℃, and the stirring time is 30-50 minutes; the curing time is 1-2 hours.

[0020] Preferably, in step 2, the amount of calcium hydroxide added is 0.5wt%-2wt% of the total mass of glycerol and epichlorohydrin; the temperature of the stirring reaction is 60-80℃ and the time is 3-5h; the mass concentration of hydrochloric acid is 5wt%-10wt%; the mass ratio of bamboo fiber nanocrystals to deionized water is 1:(10-20); the amount of urea added is 30wt%-50wt% of the mass of diammonium hydrogen phosphate; the amount of platinum catalyst added is 0.01wt%-0.05wt% of the total mass of terminal hydrogen silicone oil and allyl polyoxyethylene ether; the temperature of the reaction under nitrogen protection is 90-110℃ and the time is 3-4h; the amount of azobisisobutyronitrile added is 0.5wt%-1.5wt% of the total mass of perfluorohexylethylene and polyethylene glycol monomethyl ether; and the temperature of the addition reaction is 70-80℃ and the time is 4-6h.

[0021] Preferably, in step 3, the mixing and stirring reaction is carried out at a temperature of 55-65°C for 1-3 hours.

[0022] Preferably, in step 4, the mass ratio of 2-amino-4-hydroxy-6-methylpyrimidine to isocyanate methacrylate is 1:(1.0-1.3); the mass ratio of nano-silica to deionized water during the mixing process is 1:(10-20); the amount of silane coupling agent KH570 added is 5%-10% of the mass of nano-silica; the stirring speed is 200-400 rpm for 10-15 min; the stirring speed is 300-500 rpm for 30-60 min; and the vacuum degree of vacuum degassing is -0.08 to -0.1 MPa for 5-10 min.

[0023] Compared with the prior art, the beneficial effects of this application are as follows:

[0024] This application provides an adaptive, environmentally friendly, putty-free coating and its preparation method. A double-network interpenetrating structure is formed by an acrylic-organosilicon hybrid emulsion containing disulfide bonds and supramolecular quadruple hydrogen-bonded monomers. The reversible crosslinking of the disulfide bonds enhances the coating's self-healing ability. The supramolecular quadruple hydrogen bonds form multiple hydrogen bonds with the polar groups of the hybrid emulsion through intermolecular hydrogen bonds, increasing the oligomer strength of the film-forming agent, thereby improving the coating's film-forming properties and adhesion. Nano-silica, as a filler, is uniformly dispersed in the double-network structure through a nano-filling effect, forming hydrogen bonds with the polar groups of the film-forming agent, improving the coating's hardness and alkali resistance. Hyperbranched polyglycerol ester in the functional additives is compatible with the film-forming agent through hydroxyl hydrogen bonds, improving the coating's rheology and ensuring uniform application during construction. Phosphorylated modified bamboo fiber nanocrystals fill the coating's pores at nanoscale, and simultaneously form a "fiber-particle" multi-level filling structure with the filler nano-silica, improving the coating's density and environmental friendliness. A polyether-modified silicone oil and fluorocarbon surfactant compound defoaming system achieves efficient defoaming and foam suppression, avoiding coating defects. Attached Figure Description

[0025] Figure 1 This is a diagram showing the experimental results of the water resistance test of the adaptive environmentally friendly putty-free coating of Example 1 after one week;

[0026] Figure 2 The figure shows the experimental results of the water resistance test of the adaptive environmentally friendly putty-free coating of Comparative Example 1 after one week.

[0027] Figure 3 The figure shows the experimental results of the water resistance test of the adaptive environmentally friendly putty-free coating of Comparative Example 2 after one week.

[0028] Figure 4 The figure shows the experimental results of the water resistance test of the adaptive environmentally friendly putty-free coating of Comparative Example 3 after one week. Detailed Implementation

[0029] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0031] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] Furthermore, the terms "first" and "second" appearing in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] The following will describe in detail, with reference to specific embodiments, an adaptive and environmentally friendly putty-free coating and its preparation method provided in this application.

[0034] Example 1

[0035] An adaptive, environmentally friendly, putty-free coating and its preparation method, comprising the following steps:

[0036] Step 1: Add ethyl acetate and hydroxyethyl methacrylate to the reactor, heat to 30°C under nitrogen protection and stir for 1 hour; slowly add di(N-hydroxysuccinimide) 3,3'-dithiodipropionate, wherein the mass ratio of hydroxyethyl methacrylate to di(N-hydroxysuccinimide) 3,3'-dithiodipropionate is 1:0.6. After the addition is complete, maintain the temperature for 2 hours, and distill under reduced pressure to obtain acrylate containing disulfide bonds; add deionized water and dextran to the reaction vessel. Sodium dialkylbenzenesulfonate and half the mass of ammonium persulfate were heated to 75°C and stirred for 30 min to form an initial emulsion, wherein the mass ratio of deionized water, sodium dodecylbenzenesulfonate and ammonium persulfate was 100:2:0.3; the acrylate containing disulfide bonds was mixed with vinyltriethoxysilane at a mass ratio of 60:20 and added dropwise to the initial emulsion. After the addition was complete, the remaining mass of ammonium persulfate was added, and the mixture was kept at the temperature for 1 h to mature. After cooling to room temperature, the mixture was filtered to obtain a hybrid emulsion.

[0037] Step 2: Glycerin and epichlorohydrin were mixed at a mass ratio of 1:2.5. 0.5 wt% of calcium hydroxide (based on the total mass of glycerin and epichlorohydrin) was added, and the mixture was stirred at 60°C for 3 hours. After cooling, the pH was adjusted to 6.5 with 5 wt% hydrochloric acid, and the mixture was dried under reduced pressure to obtain hyperbranched polyglycerol ester. Bamboo fiber nanocrystals and deionized water were mixed at a mass ratio of 1:10, and diammonium hydrogen phosphate was added, with a mass ratio of bamboo fiber nanocrystals to diammonium hydrogen phosphate of 1:0.3. Urea (based on the mass of diammonium hydrogen phosphate) was also added, and the mixture was stirred at 80°C for 3 hours. h, centrifugation, washing, and drying yielded phosphorylated modified bamboo fiber nanocrystals; terminal hydrogen silicone oil and allyl polyoxyethylene ether were reacted at a mass ratio of 1:0.9, and 0.01 wt% of platinum catalyst (total mass of terminal hydrogen silicone oil and allyl polyoxyethylene ether) were added, and the reaction was carried out at 90℃ under nitrogen protection for 3 h to obtain polyether modified silicone oil; perfluorohexylethylene and polyethylene glycol monomethyl ether were reacted at a mass ratio of 1:1.0, and 0.5 wt% of azobisisobutyronitrile (total mass of perfluorohexylethylene and polyethylene glycol monomethyl ether) were added, and the reaction was carried out at 70℃ for 4 h to obtain fluorocarbon surfactant;

[0038] Step 3: The hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and leveling agent are mixed and stirred at 55°C for 1 hour in a mass ratio of 3:2:1 to obtain the functional additive; the leveling agent is composed of polyether modified silicone oil and fluorocarbon surfactant in a mass ratio of 8:1.

[0039] Step 4: First, react 2-amino-4-hydroxy-6-methylpyrimidine with isocyanate methacrylate at a mass ratio of 1:1 to obtain a supramolecular quadruple hydrogen bond monomer. Then, mix nano-silica and deionized water at a mass ratio of 1:10, add 5 wt% of silane coupling agent KH570 (by mass of nano-silica), add the hybrid emulsion and supramolecular quadruple hydrogen bond monomer, and stir at 200 rpm for 10 min. Add functional additives, add deionized water to a solid content of 40%, and continue stirring at 300 rpm for 30 min. Finally, degas under a vacuum of -0.1 MPa for 5 min, and filter to obtain an adaptive environmentally friendly putty-free coating. The mass ratio of the hybrid emulsion, nano-silica, and functional additives is 60:5:10.

[0040] Example 2

[0041] An adaptive, environmentally friendly, putty-free coating and its preparation method, comprising the following steps:

[0042] Step 1: Add ethyl acetate and hydroxypropyl acrylate to a reactor, heat to 40°C under nitrogen protection and stir for 1.5 h; slowly add 3,3'-dithiodioctylpropionamide, wherein the mass ratio of hydroxypropyl acrylate to 3,3'-dithiodioctylpropionamide is 1:0.8, and after the addition is complete, keep the reaction at this temperature for 3 h, and distill under reduced pressure to obtain acrylate containing disulfide bonds; add deionized water, sodium dodecylbenzenesulfonate and half the mass of ammonium persulfate to a reaction vessel, heat to 80°C and stir for 40 min to form an initial emulsion, wherein the mass ratio of deionized water to sodium dodecylbenzenesulfonate to ammonium persulfate is 100:2.5:0.4; mix the acrylate containing disulfide bonds with γ-methacryloyloxypropyltrimethoxysilane at a mass ratio of 70:30, and add it dropwise to the initial emulsion; after the addition is complete, add the remaining mass of ammonium persulfate, keep the reaction at this temperature for 1.5 h, cool to room temperature and filter to obtain a hybrid emulsion;

[0043] Step 2: Glycerin and epichlorohydrin were mixed at a mass ratio of 1:3. Calcium hydroxide (1 wt% of the total mass of glycerin and epichlorohydrin) was added, and the mixture was stirred at 70°C for 4 hours. After cooling, the pH was adjusted to 7 with 7 wt% hydrochloric acid, and the mixture was dried under reduced pressure to obtain hyperbranched polyglycerol ester. Bamboo fiber nanocrystals and deionized water were mixed at a mass ratio of 1:15, and diammonium hydrogen phosphate (diammonium hydrogen phosphate) was added, with a mass ratio of bamboo fiber nanocrystals to diammonium hydrogen phosphate of 1:0.5. Urea (40 wt% of the mass of diammonium hydrogen phosphate) was also added, and the mixture was stirred at 87°C for 4 hours. Phosphorylated modified bamboo fiber nanocrystals were obtained by centrifugation, washing, and drying. Hydrogen-terminated silicone oil and allyl polyoxyethylene ether were reacted at a mass ratio of 1:1, with 0.03 wt% of a platinum catalyst added. The reaction was carried out at 100°C under nitrogen protection for 3.5 h to obtain polyether-modified silicone oil. Perfluorohexylethylene and polyethylene glycol monomethyl ether were reacted at a mass ratio of 1:1.2, with 1 wt% of azobisisobutyronitrile added. The reaction was carried out at 75°C for 5 h to obtain a fluorocarbon surfactant.

[0044] Step 3: The hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and leveling agent are mixed and stirred at 60°C for 2 hours in a mass ratio of 4:3:1.5 to obtain the functional additive; the leveling agent is composed of polyether modified silicone oil and fluorocarbon surfactant in a mass ratio of 10:1.

[0045] Step 4: First, react 2-amino-4-hydroxy-6-methylpyrimidine with isocyanate methacrylate at a mass ratio of 1:1.2 to obtain a supramolecular quadruple hydrogen bond monomer. Then, mix nano-silica and deionized water at a mass ratio of 1:15, add 8 wt% of silane coupling agent KH570 (based on the mass of nano-silica), add the hybrid emulsion and supramolecular quadruple hydrogen bond monomer, and stir at 300 rpm for 12 min. Add functional additives, add deionized water to a solid content of 50%, and continue stirring at 400 rpm for 40 min. Finally, degas under a vacuum of -0.09 MPa for 8 min, and filter to obtain an adaptive environmentally friendly putty-free coating. The mass ratio of the hybrid emulsion, nano-silica, and functional additives is 70:10:20.

[0046] Example 3

[0047] An adaptive, environmentally friendly, putty-free coating and its preparation method, comprising the following steps:

[0048] Step 1: Add ethyl acetate and 2-hydroxyethyl acrylate to a reactor, heat to 50°C under nitrogen protection and stir for 2 hours; slowly add bis(2-carboxyethyl) disulfide, wherein the mass ratio of 2-hydroxyethyl acrylate to bis(2-carboxyethyl) disulfide is 1:1.0, and after the addition is complete, keep the reaction at this temperature for 4 hours, and distill under reduced pressure to obtain acrylate containing disulfide bonds; add deionized water, sodium dodecylbenzenesulfonate and half the mass of ammonium persulfate to a reaction vessel, heat to 85°C and stir for 50 minutes to form an initial emulsion, wherein the mass ratio of deionized water, sodium dodecylbenzenesulfonate and ammonium persulfate is 100:3:0.6; mix the acrylate containing disulfide bonds with vinyltrimethylsilane at a mass ratio of 80:40 and add it dropwise to the initial emulsion, and after the addition is complete, add the remaining mass of ammonium persulfate, keep the reaction at this temperature for 2 hours, cool to room temperature and filter to obtain a hybrid emulsion;

[0049] Step 2: Glycerin and epichlorohydrin were mixed at a mass ratio of 1:4.0. 2wt% calcium hydroxide (based on the total mass of glycerin and epichlorohydrin) was added, and the mixture was stirred at 80°C for 5 hours. After cooling, the pH was adjusted to 7.5 with 10wt% hydrochloric acid, and the mixture was dried under reduced pressure to obtain hyperbranched polyglycerol ester. Bamboo fiber nanocrystals and deionized water were mixed at a mass ratio of 1:20, and diammonium hydrogen phosphate was added, with a mass ratio of bamboo fiber nanocrystals to diammonium hydrogen phosphate of 1:0.8. Urea (based on the mass of diammonium hydrogen phosphate) was also added, and the mixture was stirred at 95°C for 5 hours. h, centrifugation, washing, and drying yielded phosphorylated modified bamboo fiber nanocrystals; terminal hydrogen silicone oil and allyl polyoxyethylene ether were reacted at a mass ratio of 1:1.2, and 0.05 wt% of platinum catalyst (total mass of terminal hydrogen silicone oil and allyl polyoxyethylene ether) were added, and the reaction was carried out at 110℃ under nitrogen protection for 4 h to obtain polyether modified silicone oil; perfluorohexylethylene and polyethylene glycol monomethyl ether were reacted at a mass ratio of 1:1.5, and 1.5 wt% of azobisisobutyronitrile (total mass of perfluorohexylethylene and polyethylene glycol monomethyl ether) were added, and the reaction was carried out at 80℃ for 6 h to obtain fluorocarbon surfactant;

[0050] Step 3: The hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and leveling agent are mixed and stirred at 65°C for 3 hours in a mass ratio of 5:4:2 to obtain the functional additive; the leveling agent is composed of polyether modified silicone oil and fluorocarbon surfactant in a mass ratio of 12:1.

[0051] Step 4: First, react 2-amino-4-hydroxy-6-methylpyrimidine with isocyanate methacrylate at a mass ratio of 1:1.2 to obtain a supramolecular quadruple hydrogen bond monomer. Then, mix nano-silica and deionized water at a mass ratio of 1:20, add 10 wt% of silane coupling agent KH570 (by mass of nano-silica), add the hybrid emulsion and supramolecular quadruple hydrogen bond monomer, and stir at 400 rpm for 15 min. Add functional additives, add deionized water to a solid content of 60%, and continue stirring at 500 rpm for 60 min. Finally, degas under a vacuum of -0.08 MPa for 10 min, and filter to obtain an adaptive environmentally friendly putty-free coating. The mass ratio of the hybrid emulsion, nano-silica, and functional additives is 75:15:25.

[0052] Comparative Example 1

[0053] An adaptive and environmentally friendly putty-free coating and its preparation method are disclosed. The difference between this coating and Example 1 is that the film-forming agent is an acrylic emulsion, and step 1 is omitted. In step 4, the hybrid emulsion and supramolecular four-fold hydrogen bonded monomer film-forming agent are replaced with acrylic emulsion.

[0054] Comparative Example 2

[0055] An adaptive and environmentally friendly putty-free coating and its preparation method are disclosed, which differ from Example 1 in that supramolecular quadruple hydrogen bonds are not added in step 4.

[0056] Comparative Example 3

[0057] An adaptive and environmentally friendly putty-free coating and its preparation method are disclosed, which differs from Example 1 in that no difunctional compound containing disulfide bonds is added in step 1.

[0058] Performance testing:

[0059] Adhesion test: The adaptive environmentally friendly putty-free coatings prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to vertical tensile force after cutting a grid to evaluate the bonding strength between the coating and the substrate.

[0060] Surface smoothness test: The gaps between the ground or wall surfaces of the adaptive environmentally friendly putty-free coatings prepared in Examples 1-3 and Comparative Examples 1-3 were tested using a 2-meter straightedge and a wedge gauge.

[0061] Crack resistance test: The adaptive environmentally friendly putty-free coatings prepared in Examples 1-3 and Comparative Examples 1-3 were placed in a constant temperature and humidity chamber (temperature 25℃, humidity 50%) for 28 days and the number of microcracks within 100cm² was observed.

[0062] VOC content (g / L): The VOC content of the adaptive environmentally friendly putty-free coatings prepared in Examples 1-3 and Comparative Examples 1-3 was determined by gas chromatography.

[0063] Water resistance test (7 days): The adaptive environmentally friendly putty-free coating samples prepared in Examples 1-3 and Comparative Examples 1-3 were immersed in water for 7 days, and the presence of peeling or blistering was observed.

[0064] Alkali resistance test (14 days): The adaptive environmentally friendly putty-free coatings prepared in Examples 1-3 and Comparative Examples 1-3 were immersed in saturated Ca(OH)2 solution for 14 days, and the changes in appearance and strength were observed.

[0065] Table 1. Performance test data of adaptive environmentally friendly putty-free coatings prepared in each embodiment and comparative example.

[0066]

[0067] According to Table 1, the disulfide crosslinking agent introduces disulfide bonds during the core-shell emulsion polymerization process, constructing a dynamic and reversible crosslinking network. When the coating is subjected to external force, the disulfide bonds can break and absorb energy, and after stress release, they re-crosslink, achieving a self-healing function. This characteristic makes the crack resistance of Examples 1-3 superior to Comparative Examples 1 and 3. Comparative Examples 1 and 3, lacking disulfide bonds, have 8 and 5 microcracks per 100 cm², respectively. Simultaneously, the disulfide bonds enhance the inter-segment forces of the polymer chains, as can be seen from the table, the adhesion of Examples 1-3 all reaches grade 0. In water and alkali resistance tests, the disulfide crosslinking network improves the coating density and hinders the penetration of water and alkali; therefore, Example 1 (as shown in the table) exhibits superior crack resistance. Figure 1 Example 1 and Example 2 showed no blistering in the 7-day water resistance test and no powdering in the 14-day alkali resistance test, while Comparative Example 3 showed fine cracks in the alkali resistance test due to its loose structure.

[0068] The supramolecular tetrad hydrogen-bonded monomers form a dynamic network of four hydrogen bonds through intermolecular hydrogen bonds, which interpenetrate with the disulfide crosslinking network. Their molecular recognition promotes the orderly arrangement of polymer segments; the surface smoothness of Example 3 reaches 0.9 mm, nearly twice the precision of Comparative Example 2 (no hydrogen bonds, smoothness 1.8 mm). Regarding crack resistance, the dynamic effect of hydrogen bonds assists in stress dispersion; Comparative Example 2 has 3 microcracks / 100 cm², significantly more than Examples 1-3. Furthermore, hydrogen bonding reduces solvent dependence; the VOC of Example 2 (38 g / L) is significantly lower than that of Comparative Example 2 (85 g / L), demonstrating good environmental advantages.

[0069] In the organosilicon hybrid emulsion, silane hydrolysis generates -SiOH, which condenses with the acrylate polymer to form Si-OC covalent bonds, introducing low surface energy siloxane segments. This endows the coating with excellent hydrophobicity; Examples 1-3 showed no blistering in a 7-day water resistance test, while the ordinary acrylic emulsion in Comparative Example 1 showed large-area blistering and peeling. Figure 2 Meanwhile, the flexibility of the silicon-oxygen chain segments reduces film shrinkage stress, making the smoothness of Example 1 better than that of Comparative Example 1.

[0070] Functional additives also play an indispensable role. The multi-hydroxyl structure of hyperbranched polyglycerol enhances the dispersibility of nano-SiO2, reduces surface defects caused by agglomeration, and improves the smoothness of Examples 1-3; phosphorylated bamboo fiber nanocrystals, as nanoscale rigid fillers, are embedded in the polymer network, improving the density of the coating, so that Example 2 only shows slight loss of gloss in the alkali resistance test.

[0071] The performance differences in the comparative examples also stem from defects in their chemical structures. Comparative Example 1 uses ordinary acrylic emulsion, relying on physical drying for film formation without chemical cross-linking. The resulting film is loose and porous, and a single polyether defoamer cannot completely eliminate bubbles, leading to poor water resistance, low surface smoothness, and poor alkali resistance. Comparative Example 2 lacks supramolecular quadruple hydrogen bonds, exhibiting only disulfide cross-linking. The disordered arrangement of molecular chain segments results in low stress dispersion efficiency, weak polymer-filler interfacial forces, and uneven dispersion of nano-SiO2. In the 7-day water resistance test, it showed only minor bubbling without peeling. Figure 3 Comparative Example 3, lacking sulfur bond crosslinking and relying solely on hydrogen bond physical interaction for film formation, exhibits insufficient network strength and a lack of dynamic crosslinking repair mechanism, resulting in poor performance in crack resistance, water resistance, and alkali resistance. Figure 4 .

[0072] The superior performance of the embodiments is attributed to the interactions between the components. The dual dynamic network formed by disulfide bonds and quadruple hydrogen bonds exhibits a dual effect: when faced with external forces, the hydrogen bonds break first, dissipating low energy; as stress increases, the disulfide bonds break, absorbing high energy; and after stress release, both bonds synergistically rebuild the network, achieving a "rigid-flexible" crack-resistant effect. During film formation, hydrogen bonds guide molecular pre-arrangement, while disulfide bonds fix the final structure, reducing film defects. Organosilicon and nanofillers can form an "inorganic-organic bridge" through silane coupling agents, enhancing interfacial adhesion and filler dispersibility. Simultaneously, the hydrophobicity of the silicon-oxygen segments and the low surface energy of the fluorocarbon surfactant synergistically reduce water absorption.

[0073] In summary, this coating system, through multi-dimensional chemical design involving dynamic cross-linking of disulfide bonds, molecular recognition of quadruple hydrogen bonds, and organosilicon hybridization modification, combined with the addition of nanofillers and functional additives, constructs a high-performance system characterized by "ordered structure, dynamic response, and strong interface," thus breaking through the performance bottleneck of traditional coatings at the molecular level.

[0074] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0075] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. An adaptive, environmentally friendly, putty-free coating, characterized in that, The product includes a film-forming agent, nano-silica, and functional additives; the film-forming agent includes a hybrid emulsion and a supramolecular tetrahydrobonded monomer; the hybrid emulsion is copolymerized from disulfide-bonded acrylate and organosilicon; the functional additives include hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals, and a leveling agent; the leveling agent is obtained by compounding polyether-modified silicone oil and fluorocarbon surfactant.

2. The adaptive environmentally friendly putty-free coating according to claim 1, characterized in that, The supramolecular tetrahydrobonded monomer is obtained by reacting 2-amino-4-hydroxy-6-methylpyrimidine with isocyanoethyl methacrylate; the disulfide-containing acrylate is obtained by reacting a hydroxyl-containing acrylate monomer with a disulfide-containing bifunctional compound; the hydroxyl-containing acrylate monomer includes any one of hydroxyethyl methacrylate, hydroxypropyl acrylate, and 2-hydroxyethyl acrylate; the disulfide-containing bifunctional compound includes any one of di(N-hydroxysuccinimide) 3,3'-dithiodipropionate, 3,3'-dithiodioctylpropionamide, and bis(2-carboxyethyl) disulfide; the organosilicon includes any one of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethylsilane.

3. The adaptive environmentally friendly putty-free coating according to claim 2, characterized in that, The hyperbranched polyglycerol ester is obtained by reacting glycerol with epichlorohydrin; the phosphorylated modified bamboo fiber nanocrystals are obtained by reacting bamboo fiber nanocrystals with diammonium hydrogen phosphate; the polyether modified silicone oil is obtained by reacting terminal hydrogen silicone oil with allyl polyoxyethylene ether; and the fluorocarbon surfactant is obtained by reacting perfluorohexylethylene with polyethylene glycol monomethyl ether.

4. The adaptive environmentally friendly putty-free coating according to claim 3, characterized in that, The mass ratio of the film-forming agent, nano-silica, and functional additives is (60-75):(5-15):(10-25); the mass ratio of the disulfide-bonded acrylate, organosilicon, and supramolecular tetrahydrobonded monomer is (60-80):(20-40):1; the mass ratio of the hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals, and leveling agent is (3-5):(2-4):(1-2); and the mass ratio of the polyether-modified silicone oil and fluorocarbon surfactant is (8-12):

1.

5. The adaptive environmentally friendly putty-free coating according to claim 4, characterized in that, The mass ratio of the hydroxyl-containing acrylate monomer to the disulfide-containing bifunctional compound is 1:(0.6-1.0); the mass ratio of glycerol to epichlorohydrin is 1:(2.5-4.0); the mass ratio of bamboo fiber nanocrystals to diammonium hydrogen phosphate is 1:(0.3-0.8); the mass ratio of terminal hydrogen silicone oil to allyl polyoxyethylene ether is 1:(0.9-1.2); and the mass ratio of perfluorohexylethylene to polyethylene glycol monomethyl ether is 1:(1.0-1.5).

6. A method for preparing an adaptive, environmentally friendly, putty-free coating according to claim 5, characterized in that, Includes the following steps: Step 1: Add ethyl acetate and hydroxyl-containing acrylate monomers to a reactor, heat and stir under nitrogen protection; add a disulfide-bonded bifunctional compound dropwise, maintain the temperature after addition, and distill under reduced pressure to obtain disulfide-bonded acrylate; add deionized water, sodium dodecylbenzenesulfonate and half the mass of ammonium persulfate to a reaction vessel, heat and stir to form an initial emulsion; mix the disulfide-bonded acrylate with organosilicon, add it dropwise to the initial emulsion, add the remaining mass of ammonium persulfate after addition, maintain the temperature for aging, cool to room temperature and filter to obtain a hybrid emulsion; Step 2: Mix glycerol and epichlorohydrin, add calcium hydroxide, and stir to react; after cooling, adjust the pH to 6.5-7.5 with hydrochloric acid, and dry under reduced pressure to obtain hyperbranched polyglycerol ester; mix bamboo fiber nanocrystals and deionized water, add diammonium hydrogen phosphate, and simultaneously add urea, stir to react, centrifuge, wash, and dry to obtain phosphorylated modified bamboo fiber nanocrystals; take terminal hydrogen silicone oil and allyl polyoxyethylene ether, add platinum catalyst, and react under nitrogen protection to obtain polyether modified silicone oil; take perfluorohexylethylene and polyethylene glycol monomethyl ether to react, add azobisisobutyronitrile, and carry out an addition reaction to obtain fluorocarbon surfactant; Step 3: Mix and stir the hyperbranched polyglycerol ester, phosphorylated modified bamboo fiber nanocrystals and leveling agent to obtain functional additives; Step 4: First, react 2-amino-4-hydroxy-6-methylpyrimidine with isocyanate methacrylate to prepare a supramolecular four-fold hydrogen bond monomer. Then, mix nano-silica and deionized water, add silane coupling agent KH570, add the hybrid emulsion and the supramolecular four-fold hydrogen bond monomer, and stir. Add the functional additives, add deionized water to a solid content of 40%-60%, and continue stirring. Finally, degas under vacuum and filter to obtain an adaptive environmentally friendly putty-free coating.

7. The method for preparing an adaptive, environmentally friendly, putty-free coating according to claim 6, characterized in that, In step 1, the mass ratio of ethyl acetate to hydroxyl-containing acrylate monomer is (1.5-3):1; the heating temperature under nitrogen protection is 30-50℃, and the stirring time is 1-2 hours; the reaction time after the addition is 2-4 hours; the mass ratio of deionized water, sodium dodecylbenzenesulfonate, and ammonium persulfate is 100:(2-3):(0.3-0.6); the temperature for heating and stirring to form the initial emulsion is 75-85℃, and the stirring time is 30-50 minutes; the curing time is 1-2 hours.

8. The method for preparing an adaptive, environmentally friendly, putty-free coating according to claim 6, characterized in that, In step 2, the amount of calcium hydroxide added is 0.5wt%-2wt% of the total mass of glycerol and epichlorohydrin; the temperature of the stirring reaction is 60-80℃ and the time is 3-5h; the mass concentration of hydrochloric acid is 5wt%-10wt%; the mass ratio of bamboo fiber nanocrystals to deionized water is 1:(10-20); the amount of urea added is 30wt%-50wt% of the mass of diammonium hydrogen phosphate; the amount of platinum catalyst added is 0.01wt%-0.05wt% of the total mass of terminal hydrogen silicone oil and allyl polyoxyethylene ether; the temperature of the reaction under nitrogen protection is 90-110℃ and the time is 3-4h; the amount of azobisisobutyronitrile added is 0.5wt%-1.5wt% of the total mass of perfluorohexylethylene and polyethylene glycol monomethyl ether; the temperature of the addition reaction is 70-80℃ and the time is 4-6h.

9. The method for preparing an adaptive, environmentally friendly, putty-free coating according to claim 6, characterized in that, In step 3, the mixing and stirring reaction is carried out at a temperature of 55-65℃ for 1-3 hours.

10. The method for preparing an adaptive, environmentally friendly, putty-free coating according to claim 6, characterized in that, In step 4, the mass ratio of 2-amino-4-hydroxy-6-methylpyrimidine to isocyanate methacrylate is 1:(1.0-1.3); the mass ratio of nano-silica to deionized water during the mixing process is 1:(10-20); the amount of silane coupling agent KH570 added is 5%-10% of the mass of nano-silica; the stirring speed is 200-400 rpm for 10-15 min; the stirring speed is 300-500 rpm for 30-60 min; and the vacuum degree of vacuum degassing is -0.08 to -0.1 MPa for 5-10 min.

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