Highly permeable alkali-resistant nitrate coating and preparation method thereof

Abstract

The application discloses a kind of high penetration nitrate alkali-resistant coating and preparation method thereof, belong to the technical field of coating composition. Including the following steps: bactericide, fungicide, propylene glycol, defoaming agent, wetting agent, active component, organic silicon modified polyacrylate emulsion, modified halloysite nanotube, KH550 modified silica sol and film-forming additive are sequentially added to deionized water, stirred uniformly and then filtered, and the high penetration nitrate alkali-resistant coating is obtained after discharging;The modified halloysite nanotube is prepared by stepwise electrostatic self-assembly of poly (4-sodium styrene sulfonate) and polydiallyldimethylammonium chloride, and the inner and outer surfaces of halloysite nanotube are modified;It is used to improve the permeability, alkali resistance and nitrate resistance, mildew resistance and antibacterial capacity of wall coating.

Description

Technical Field

[0001] This invention belongs to the field of coating composition technology, specifically relating to a high-penetration nitrate-alkali resistant coating and its preparation method. Background Technology

[0002] Walls are an important part of building interior decoration and a key factor affecting the aesthetics and health of the living environment. However, during long-term use, walls generally face a series of problems caused by the migration of moisture from the wall interior, the precipitation of soluble salts (such as salts and nitrates), and the growth of mold. These problems not only seriously damage the decorative effect of the walls, but also pose a threat to the health of the residents and the durability of the building.

[0003] Specifically, existing wall systems mainly suffer from the following technical defects:

[0004] 1) Wall rot and mold problems caused by efflorescence and nitrification: When silicates in concrete or mortar come into contact with air or moisture within the wall, they hydrolyze, forming hydroxides with low solubility. As temperatures rise and moisture gradually evaporates, some calcium hydroxide dissolves and is carried to the concrete surface, causing efflorescence. Furthermore, when the wall becomes damp, anaerobic bacteria and mold thrive in the humid, nutrient-rich environment. These microorganisms convert nitrogenous substances in the wall materials (such as cement admixtures and organic fillers) into nitrites and nitrates, which migrate to the wall surface with moisture and precipitate, forming nitrate efflorescence. Long-term erosion by salts and nitrates damages the film-forming structure of putty, latex paint, and other coatings, leading to powdering and peeling. It also provides a more suitable growth environment for mold spores, causing the wall to rot and turn black. In traditional renovations, due to a lack of scientific early diagnosis and targeted prevention measures, efflorescence and nitrate efflorescence problems are often overlooked until large areas of the coating are damaged, at which point irreversible damage has already occurred. Even with repeated repairs or reinstallation, if the continuous precipitation of salts and nitrates cannot be stopped, the problem will recur, and the frequency of occurrence will increase. Traditional wall repair methods are no longer effective for this type of problem.

[0005] 2) Yellowing and loss of luster on the walls: Salts, nitrates, and mold metabolites leached from within the wall, as well as the performance degradation of the coating itself due to hydrolysis and oxidation, are all important causes of wall yellowing. Traditional ordinary interior wall paints lack the ability to effectively block salts and nitrates from the wall, and cannot inhibit yellowing from the root cause. They can only cover it up with recoating later, which is a temporary solution.

[0006] 3) Wall bulging and peeling issues; Blistering and peeling of walls are usually direct signs of dampness and mold growth. When walls are in a damp environment for extended periods (such as kitchen / bathroom partitions, exterior wall leaks, or damp floors), mold spores easily proliferate and spread under suitable temperature and humidity conditions, damaging the adhesion between the coating and the substrate, leading to blistering and peeling. Internal defects such as voids and cracks in the wall can also cause moisture to accumulate during rain or when damp, exacerbating peeling and flaking. Mold not only releases unpleasant odors, but its spores can also harm human health, easily triggering respiratory illnesses and allergic reactions.

[0007] To address the aforementioned issues, while some alkali-resistant primer products have been developed in the industry, such as the alkali-resistant coating disclosed in patent document CN118703067B, this coating relies solely on physical adsorption and neutralization with weak acids, lacking chemical precipitation and chelation. Therefore, it cannot eradicate deep-seated alkali sources in the wall, its alkali-resistant effect is short-lived and prone to recurrence, and the powder accumulates into a film that cannot penetrate the interior of the wall, only providing surface coverage and failing to fundamentally prevent efflorescence and alkali blooming. Therefore, developing a wall coating that combines high permeability, strong alkali resistance, and long-lasting anti-mildew and antibacterial functions has become a critical technical problem urgently needing to be solved in the current building decoration field. Summary of the Invention

[0008] The purpose of this invention is to provide a high-penetration alkali-resistant coating and its preparation method, which can improve the permeability, alkali-resistant and nitrate-resistant ability, and mildew-proof and antibacterial ability of wall coatings.

[0009] The objective of this invention can be achieved through the following technical solutions: A method for preparing a high-penetration nitrate-alkali resistant coating includes the following steps: Add bactericide, mildew inhibitor and propylene glycol to deionized water in sequence, stir evenly, then add defoamer, wetting agent and active component, stir evenly, then add organosilicon modified polyacrylate emulsion, modified halloysite nanotubes and KH550 modified silica sol, stir evenly, then add film-forming aid, stir evenly, filter, and discharge to obtain the high-penetration nitrate-alkali resistant coating. The modified halloysite nanotubes were prepared by stepwise electrostatic self-assembly of poly(sodium 4-styrene sulfonate) and polydiallyl dimethyl ammonium chloride to modify the inner and outer surfaces of the halloysite nanotubes.

[0010] Through stepwise electrostatic self-assembly of poly(4-styrene sulfonate) and polydiallyldimethylammonium chloride, the electrostatic interaction of poly(4-styrene sulfonate) allows it to be tightly adsorbed onto the positively charged region inside the halloysite nanotube. Simultaneously, through hydrogen bonding and other interactions, it covers the outer wall, forming a negatively charged poly(4-styrene sulfonate) layer on both the inner and outer surfaces of the halloysite nanotube. This eliminates the original charge difference. Furthermore, through electrostatic interaction, polydiallyldimethylammonium chloride excessively covers the poly(4-styrene sulfonate) layer, resulting in a positively charged modified halloysite nanotube. This enhances the adsorption capacity and binding strength for alkali ions and nitrates in the wall, achieving long-term stable alkali locking and preventing repeated alkali and nitrate blooms.

[0011] Modified halloysite nanotubes and KH550 modified silica sol form an interpenetrating cross-linked structure, creating a directional, layered barrier network inside the coating. This physically blocks the channels for the migration and diffusion of alkali salts from inside the wall to the surface, inhibiting efflorescence, whitening, and crystallization from the migration path.

[0012] Organosilicon-modified polyacrylate emulsion provides flexibility and film-forming properties, modified halloysite nanotubes provide strong adsorption and barrier properties, and KH550 modified silica sol provides hardness and sealing properties. The three work together to achieve high permeability, strong alkali resistance, high sealing and crack resistance.

[0013] As a preferred embodiment of the present invention, the method for preparing the organosilicon-modified polyacrylate emulsion includes the following steps: A1. In a nitrogen atmosphere, take the double-ended epoxypropoxypropyl polydimethylsiloxane and toluene, mix them evenly, heat to 80-90℃, and then add a mixture of acrylic acid, p-hydroxyanisole, triethylamine and toluene under reflux heating and stirring. Heat to 100-105℃ and continue stirring for 2-4 hours. After the reaction product is treated by vacuum distillation, it is discharged and dried under vacuum to obtain the double-ended acrylate polysiloxane. A2. Add sodium bicarbonate and deionized water to a reactor equipped with a reflux stirring device. Turn on the stirring and purge with nitrogen for protection. First, add 1 / 3 of the total mass of the core layer pre-emulsion and 1 / 6 of the total mass of the initiator. Heat to 75-80℃. After the system shows a blue light, add the remaining core layer pre-emulsion and 1 / 3 of the total mass of the initiator dropwise at a uniform rate. After the addition is complete, keep the temperature for 10-20 minutes to obtain the core layer emulsion. Then, add the shell layer pre-emulsion and the remaining initiator dropwise at a uniform rate to the core layer emulsion. After the addition is complete, continue to keep the temperature for 2-3 hours. Control the pH of the system to 5-6 throughout the reaction. After the reaction is complete, cool to room temperature, filter and discharge to obtain the organosilicon-modified polyacrylate emulsion.

[0014] By first preparing dual-terminated acrylate-based polysiloxanes and then using core-shell seed emulsion polymerization to prepare silicone-modified polyacrylate emulsions, silicone segments are covalently integrated into the polyacrylate backbone, solving the problems of easy phase separation and easy migration and precipitation of silicone in traditional physical blending systems. At the same time, a core-shell latex particle structure with a flexible interior and a rigid exterior is formed, giving the coating excellent elasticity, adhesion, high permeability, high hardness, water resistance, weather resistance, scrub resistance, and low surface energy hydrophobicity. The reaction process is stable, the latex particle size is uniform, and it has good compatibility with other components in the coating, significantly improving the overall performance of the coating.

[0015] As a preferred embodiment of the present invention, in step A1, the mass ratio of the double-sided epoxypropoxypropyl-terminated polydimethylsiloxane, toluene, acrylic acid, p-hydroxyanisole, triethylamine, and toluene is 100:50:39.2:0.2:1.0:50.

[0016] As a preferred embodiment of the present invention, in step A2, the core layer pre-emulsion is prepared by homogenizing and emulsifying butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, diacrylate-terminated polysiloxane, emulsifier, and deionized water; the mass ratio of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, diacrylate-terminated polysiloxane, emulsifier, and deionized water is 50-60:25-35:4-6:15-22:5-7:150-250.

[0017] As a preferred embodiment of the present invention, in step A2, the shell pre-emulsion is prepared by homogenizing and emulsifying butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, emulsifier and deionized water; the mass ratio of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, emulsifier and deionized water is 55-65:30-35:4-6:3-5:150-250.

[0018] As a preferred embodiment of the present invention, the initiator is prepared by dissolving 2,2'-azobis(2-methylpropanediamine) dihydrochloride in deionized water; the mass ratio of 2,2'-azobis(2-methylpropanediamine) dihydrochloride to deionized water is 1-2:20-30.

[0019] The use of cationic initiator 2,2'-azobis(2-methylpropanediamine) dihydrochloride enables the prepared organosilicon-modified polyacrylate emulsion particles to carry a positive potential on their surface. This allows them to form an electrostatic synergistic effect with the overall positively charged modified halloysite nanotubes, achieving highly uniform dispersion of each component without agglomeration or sedimentation. At the same time, the cationic sites on the emulsion surface can strongly adsorb free alkali / salt anions inside the wall, achieving in-situ alkali locking and further improving the coating's anti-efflorescence and anti-nitrification effects.

[0020] As a preferred embodiment of the present invention, the preparation method of the KH550 modified silica sol includes the following steps: B1. Dissolve silane coupling agent KH550 in a mixture of anhydrous ethanol and deionized water, stir until homogeneous, adjust the pH of the system to 4-5, and pre-hydrolyze at room temperature for 30-40 min to obtain KH550 solution; the volume ratio of silane coupling agent KH550, anhydrous ethanol and deionized water is 4-5:80:20. B2. Place the silica sol in a reaction vessel, and under the conditions of heating, condensing, and stirring in a 60°C water bath, add the KH550 solution dropwise into the silica sol. Stir at a constant temperature for 3-4 hours, centrifuge, collect the solid phase, wash, and dry to obtain KH550 modified silica sol. The ratio of silica sol to KH550 solution is 100g: 20-30mL.

[0021] The silane coupling agent KH550 was pre-hydrolyzed in an ethanol-water mixture at pH 4-5 to ensure complete dissolution and release of active silanol groups. Then, the KH550 solution was added dropwise to silica sol at a constant temperature of 60°C for graft modification, allowing KH550 to covalently bond to the silica sol surface, resulting in an aminated modified silica sol. This preparation method uniformly introduces active amino groups onto the silica sol surface, giving it a positive charge and excellent electrostatic compatibility and dispersion stability with organosilicon-modified polyacrylate emulsions and modified halloysite nanotubes. Simultaneously, it further enhances the coating's penetration and sealing properties, strengthens the capillary sealing effect on walls, and further improves resistance to alkali and efflorescence.

[0022] Another object of the present invention is to provide a high-penetration nitrate-alkali-resistant coating prepared by the above-mentioned high-penetration nitrate-alkali-resistant coating preparation method, wherein the mass ratio of deionized water, bactericide, mildew inhibitor, propylene glycol, defoamer, wetting agent, active component, organosilicon modified polyacrylate emulsion, modified halloysite nanotubes, KH550 modified silica sol and film-forming aid is 38.4-56:0.1-0.3:0.2-0.3:0.7-0.9:0.1-0.2:0.1-0.3:1.8-2.6:35-45:2-3:3-6:1-3.

[0023] As a preferred embodiment of the present invention, the active components include precipitants, chelating agents, and supplements; The mass ratio of the precipitant, chelating agent, and supplement is 2-3:2-4:4-5; The precipitant includes at least one of sodium carbonate, sodium sulfate, sodium fluorosilicate, and potassium phosphate; The chelating agent includes at least one of sodium gluconate, potassium sodium tartrate, and tetrasodium ethylenediaminetetraacetate. The supplement comprises calcium formate and calcium carbonate; the mass ratio of calcium formate to calcium carbonate is 3-5:1-2; The bactericide includes at least one of benzisothiazolinone, chloromethylisothiazolinone, and methylisothiazolinone; The antifungal agent includes at least one of TIO-20, Sol EPW and KP-M21; The defoamer is a polyether-modified polysiloxane defoamer; The wetting agent includes at least one of sodium polycarboxylate dispersant, alkyl polyoxyethylene ether, fatty alcohol polyoxyethylene ether and fatty acid polyoxyethylene ester; The film-forming aid includes at least one of alcohol ester dodecyl, propylene glycol methyl ether acetate, and propylene glycol butyl ether.

[0024] The active components of this invention are compounded from precipitants, chelating agents, and supplements in a specific mass ratio. Through the synergistic effects of chemical precipitation, ion chelation, and physical filling, they achieve deep alkali locking and thorough alkali sealing, inhibiting efflorescence and efflorescence on walls at their source. The bactericide and mildew inhibitor, used in combination, endow the coating with excellent antibacterial and mildew-proof properties, extending the coating's service life. The defoamer and wetting agent, working together, effectively improve the coating's workability, eliminate bubbles, improve dispersion, and enhance film smoothness. The film-forming aid optimizes the coating's film-forming performance, improving adhesion, density, water resistance, and washability. The scientific combination of these components gives the coating a comprehensive range of properties, including high penetration, strong alkali resistance, long-lasting mildew prevention, stable application, and excellent film formation.

[0025] As a preferred embodiment of the present invention, the particle size of the heavy calcium carbonate is 1000-1200 mesh.

[0026] By controlling the particle size of heavy calcium carbonate to 1000-1200 mesh, it combines the characteristics of efficient filling, good dispersion, excellent application, and stable film formation in coatings. It can effectively fill the internal voids of the coating, improve the density and sealing properties of the coating, and is also well compatible with other components in the system, ensuring stable coating storage, smooth application, and a smooth film formation. Furthermore, it can work synergistically with active components to further enhance the capillary sealing effect of the wall and strengthen its resistance to alkali and nitrification.

[0027] The beneficial effects of this invention are: (1) The high-penetration nitrate-alkali resistant coating and its preparation method disclosed in this invention utilize the synergistic effect of stepwise electrostatic self-assembly modified halloysite nanotubes, KH550 modified silica sol, and organosilicon modified polyacrylate emulsion. The organosilicon modified polyacrylate emulsion, in conjunction with KH550 modified silica sol, gives the coating excellent permeability, allowing it to quickly penetrate into the capillary pores inside the wall, achieving deep sealing, blocking the migration space of salts and alkalis, and significantly improving the resistance to nitrate efflorescence and alkali efflorescence. The stepwise electrostatic self-assembly of poly(4-styrene sulfonate) and polydiallyl dimethyl ammonium chloride is used to modify halloysite nanotubes. The inner and outer surfaces of the halloysite nanotubes are simultaneously modified to impart an overall positive charge, enabling them to strongly adsorb alkali anions and nitrate anions in the wall, thereby increasing the adsorption capacity and binding strength. This achieves in-situ locking of alkali and salt, preventing free ions from migrating to the surface with moisture and forming nitrate and alkali blooms. The modified halloysite nanotubes and KH550 modified silica sol are oriented and interwoven in the coating to form a continuous and dense layered inorganic barrier network, which can effectively cut off the channels for alkali and salt ions to diffuse to the coating surface. Through physical barrier, crystallization, whitening, and nitrate blooms are further inhibited, making the anti-alkali and anti-nitrate effect more durable and without rebound.

[0028] (2) The high-penetration nitrate-alkali resistant coating and its preparation method disclosed in this invention, by adding active components, precipitants (sodium carbonate, sodium sulfate, sodium fluorosilicate, potassium phosphate) can quickly generate stable insoluble salts with free calcium ions and alkali ions in the wall, and solidify the alkali source in situ; chelating agents (sodium gluconate, potassium sodium tartrate, tetrasodium EDTA) have strong complexing ability for metal ions such as calcium, magnesium, and sodium, preventing ion migration and crystallization; supplementing agents (calcium formate, heavy calcium carbonate) can quickly strengthen the base layer, seal pores, and increase density, further preventing alkali salt penetration; the three work together to make the anti-nitrate-alkali effect more thorough and without rebound.

[0029] (3) The high-penetration nitrate-alkali resistant coating and its preparation method disclosed in this invention are compounded with benzisothiazolinone, chloromethylisothiazolinone, methylisothiazolinone bactericides and TIO-20, Sol EPW and KP-M21 antifungal agents to give the coating strong antibacterial and antifungal functions, avoid the blackening, mold growth and powdering of the wall surface due to efflorescence and nitrate in high humidity environment, and further improve the appearance and durability of the coating.

[0030] (4) The high-penetration nitrate-alkali resistant coating and its preparation method disclosed in this invention achieve long-lasting high-penetration nitrate and alkali resistance through the triple synergy of organic-inorganic-active components: the organosilicon-modified polyacrylate emulsion provides high penetration, strong film formation, and high flexibility; the modified halloysite nanotubes provide high-density ion adsorption and layered barrier; the KH550 modified silica sol provides nano-sealing, high hardness, and high adhesion; and the active components provide chemical fixation of nitrates and alkalis. The components work synergistically and do not interfere with each other under specific ratios to form a high-performance nitrate-alkali resistant coating, fundamentally solving the long-standing problems of efflorescence, nitrate efflorescence, whitening, cracking, and peeling on building walls. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0032] The raw materials used in this invention are explained below: Bilaterally epoxypropyl-terminated polydimethylsiloxane was purchased from Zhengzhou Gaike Technology Co., Ltd., CAS: 102782-97-8, epoxy value 0.528mol / 100g. A polydiallyldimethylammonium chloride solution, wherein the weight-average molecular weight of polydiallyldimethylammonium chloride is Mw = 200,000 g / mol, and the solid content is 20 wt%. Sodium poly(4-styrenesulfonate), Shanghai Jizhi Biochemical Technology Co., Ltd., CAS: 25704-18-1, Product No.: P84510; Silica sol, containing 25% silica by mass.

[0033] Example 1 90 parts by weight of bi-glycidoxypropyl-terminated polydimethylsiloxane and 50 parts by weight of ditoluene were mixed and stirred mechanically at 300 rpm for 10 min until the system was homogeneous and showed no obvious stratification, yielding material A. 35 parts by weight of acrylic acid, 0.15 parts by weight of p-hydroxyanisole, 1.0 part by weight of triethylamine, and 50 parts by weight of ditoluene were mixed and stirred mechanically at 300 rpm for 10 min until the system was homogeneous, yielding material B. Under a nitrogen atmosphere, the reaction vessel containing material A was placed in an oil bath heating device. Mechanical stirring was started at 300 rpm, and the temperature was increased to 80°C at a rate of 2°C / min. Then, material B was added dropwise under reflux heating and stirring. After the addition was complete, the temperature was continued to rise to 100°C at a rate of 2°C / min and stirring was continued for 4 h. During the reaction, samples were taken to determine the acid value of the system. When the acid value of the reaction product was less than 3 mg / L... The reaction reaches its endpoint when KOH / g of the reaction product is used; wherein, the acid value refers to the number of milligrams of potassium hydroxide required to neutralize the acidic component in 1g of the reaction product. The reaction product is discharged after being treated by vacuum distillation and then vacuum dried for 6 hours to obtain a double-terminated acrylate polysiloxane.

[0034] Mix 50 parts by weight of butyl acrylate, 25 parts by weight of methyl methacrylate, 4 parts by weight of 2-hydroxyethyl acrylate, and 15 parts by weight of diacrylate-terminated polysiloxane. Stir at 300 rpm for 10 minutes at room temperature using mechanical stirring. Add 5 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 1:1 mass ratio) and 150 parts by weight of deionized water. Homogenize at 5000 rpm for 5 minutes to obtain a core layer pre-emulsion, which should be prepared and used immediately. Mix 55 parts by weight of butyl acrylate, 30 parts by weight of methyl methacrylate, and 4 parts by weight of 2-hydroxyethyl acrylate. Stir at 300 rpm for 10 minutes at room temperature using mechanical stirring. Add 3 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 1:1 mass ratio) and 150 parts by weight of deionized water. Homogenize at 5000 rpm for 5 minutes to obtain a core layer pre-emulsion. Homogenize and emulsify for 5 min to obtain the shell pre-emulsion, which should be prepared and used immediately. Dissolve 1 part by weight of 2,2'-azobis(2-methylpropanediamine) dihydrochloride in 20 parts by weight of deionized water to obtain the initiator. Add 1 part by weight of sodium bicarbonate and 200 parts by weight of deionized water to a reactor equipped with a reflux condenser and a stirrer. Turn on the stirrer and purge with nitrogen for protection. First, add 1 / 3 of the total mass of the core pre-emulsion and 1 / 6 of the total mass of the initiator. Use a water bath heating method. The temperature was increased to 75℃ at a rate of 2℃ / min. After the system showed blue light, 1 / 3 of the total mass of the remaining core layer pre-emulsion and initiator was added dropwise at a uniform rate. After the addition was completed, the temperature was maintained for 10 min to obtain the core layer emulsion. Subsequently, the shell layer pre-emulsion and the remaining initiator were added dropwise at a uniform rate to the core layer emulsion. After the addition was completed, the temperature was maintained for another 2 h. The pH of the system was controlled at 5 throughout the reaction. After the reaction was completed, the system was cooled to room temperature, filtered, and discharged to obtain the organosilicon-modified polyacrylate emulsion.

[0035] Mix 0.3 parts by mass of sodium poly(4-styrene sulfonate) and 100 parts by mass of deionized water at room temperature using magnetic stirring at a speed of 300 r / min for 10 min. Add 1.0 part by mass of halloysite nanotubes and stir magnetically for 20 h. Centrifuge and collect the solid phase, washing it repeatedly with deionized water until the pH of the filtrate is neutral. Collect the lower solid product to obtain material C. Disperse 1.0 part by mass of material C in 10 parts by mass of deionized water and add 0.2 parts by mass of polydiallyldimethylammonium chloride solution. Stir for 20 h and centrifuge. Collect the solid phase and wash it repeatedly with deionized water until the pH of the filtrate is neutral. Vacuum dry at 60 °C for 10 h to obtain modified halloysite nanotubes.

[0036] Take 4 volumes of silane coupling agent KH550 and dissolve it in a mixed system consisting of 80 volumes of anhydrous ethanol and 20 volumes of deionized water. Stir the mixture magnetically for 10 minutes at room temperature with a stirring speed of 300 r / min. Adjust the pH of the system to 4 with 0.1 mol / L hydrochloric acid solution and pre-hydrolyze at room temperature for 30 minutes to obtain KH550 solution.

[0037] Take 100 parts by mass of silica sol and place it in a reaction vessel. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60°C, add 18 parts by mass of KH550 solution dropwise into the silica sol. Stir at a constant temperature for 3 hours, centrifuge to separate, collect the solid phase, wash and dry to obtain KH550 modified silica sol.

[0038] Add 56 parts by weight of deionized water to the dispersion vessel, maintain a stirring speed of 300 r / min, and then add 0.1 parts by weight of the bactericide benzisothiazolinone, 0.2 parts by weight of the antifungal agent TIO-20, and 0.7 parts by weight of propylene glycol in sequence. Stir for 5 min, then add 0.1 parts by weight of the polyether-modified polysiloxane defoamer, 0.1 parts by weight of the wetting agent alkyl polyoxyethylene ether, and 1.8 parts by weight of the active component (this active component includes 2 parts by weight of precipitant, 2 parts by weight of chelating agent, and 5 parts by weight of supplementing agent; the precipitant consists of 2 parts by weight of sodium carbonate, 3 parts by weight of sodium sulfate, 0.4 parts by weight of sodium fluorosilicate, and 6 parts by weight of sodium carbonate). The composition is potassium phosphate; the chelating agent consists of 5 parts by mass of sodium gluconate, 1 part by mass of potassium sodium tartrate, and 1 part by mass of tetrasodium ethylenediaminetetraacetate; the supplement consists of 3 parts by mass of calcium formate and 2 parts by mass of heavy calcium carbonate with a particle size of 1000 mesh), and stirring is continued for 3 min; then 35 parts by mass of organosilicon modified polyacrylate emulsion, 2 parts by mass of modified halloysite nanotubes, and 3 parts by mass of KH550 modified silica sol are added, and stirring is continued for 10 min at a speed of 600 r / min. Then 1 part by mass of film-forming aid alcohol ester dodecyl is added, and stirring is continued for 5 min. After filtration, the material is discharged to obtain a high-penetration nitrate-alkali resistant coating.

[0039] Example 2 95 parts by mass of bi-glycidoxypropyl-terminated polydimethylsiloxane and 52 parts by mass of xylene were mixed and stirred mechanically at 300 rpm for 12 min to obtain material A. 38 parts by mass of acrylic acid, 0.18 parts by mass of p-hydroxyanisole, 1.05 parts by mass of triethylamine, and 53 parts by mass of xylene were mixed and stirred mechanically at 300 rpm for 12 min to obtain material B. Under a nitrogen atmosphere, the reaction vessel containing material A was placed in an oil bath heating device, and mechanical stirring was started at 300 rpm. The temperature was increased to 85°C at a rate of 2°C / min. Then, material B was added dropwise under reflux heating and stirring. After the addition was complete, the temperature was continued to rise to 103°C at a rate of 2°C / min and stirred for 3 h. During the reaction, samples were taken to determine the acid value of the system. When the acid value of the reaction product was less than 3 mg / L... The reaction reached its endpoint when KOH / g of the product was reacted. The product was then discharged after vacuum distillation and vacuum dried for 7 hours to obtain a double-terminated acrylate polysiloxane.

[0040] Mix 52 parts by weight of butyl acrylate, 28 parts by weight of methyl methacrylate, 4.5 parts by weight of 2-hydroxyethyl acrylate, and 17 parts by weight of diacrylate-terminated polysiloxane. Stir at 300 rpm for 12 minutes at room temperature using mechanical stirring. Add 5.5 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a mass ratio of 1.5:1) and 180 parts by weight of deionized water. Homogenize at 6000 rpm for 8 minutes to obtain a core layer pre-emulsion, which should be prepared and used immediately. Mix 58 parts by weight of butyl acrylate, 32 parts by weight of methyl methacrylate, and 4.5 parts by weight of 2-hydroxyethyl acrylate. Stir at 300 rpm for 12 minutes at room temperature using mechanical stirring. Add 3.5 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a mass ratio of 1.5:1) and 180 parts by weight of deionized water. Homogenize at 6000 rpm for 8 minutes to obtain a core layer pre-emulsion. Homogenize and emulsify at a constant speed for 7 min to obtain a shell pre-emulsion, which should be prepared and used immediately. Dissolve 1.2 parts by weight of 2,2'-azobis(2-methylpropanediamine) dihydrochloride in 22 parts by weight of deionized water to obtain an initiator. Add 1.3 parts by weight of sodium bicarbonate and 200 parts by weight of deionized water to a reactor equipped with a reflux condenser and a stirrer. Start stirring and purge with nitrogen for protection. First, add 1 / 3 of the total mass of the core pre-emulsion and 1 / 6 of the total mass of the initiator, and then add the mixture using a water bath. The system was heated to 78°C at a rate of 2°C / min. After the system emitted blue light, 1 / 3 of the total mass of the remaining core pre-emulsion and initiator was added dropwise at a uniform rate. The mixture was kept at this temperature for 15 minutes after the addition was completed to obtain a core emulsion. Subsequently, the shell pre-emulsion and the remaining initiator were added dropwise to the core emulsion at a uniform rate. The mixture was kept at this temperature for another 2.5 hours after the addition was completed. The pH of the system was maintained at 5 throughout the reaction. After the reaction was completed, the mixture was cooled to room temperature, filtered, and discharged to obtain an organosilicon-modified polyacrylate emulsion.

[0041] Mix 0.4 parts by mass of poly(4-styrene sulfonate) and 100 parts by mass of deionized water at room temperature using magnetic stirring at a speed of 350 r / min for 10 min. Add 1.05 parts by mass of halloysite nanotubes and stir magnetically for 25 h. Centrifuge and collect the solid phase, washing it repeatedly with deionized water until the pH of the filtrate is neutral. Collect the lower solid product to obtain material C. Disperse 1.0 part by mass of material C in 15 parts by mass of deionized water and add 0.25 parts by mass of polydiallyldimethylammonium chloride solution. Stir for 25 h and centrifuge. Collect the solid phase and wash it repeatedly with deionized water until the pH of the filtrate is neutral. Vacuum dry at 60 °C for 12 h to obtain modified halloysite nanotubes.

[0042] 4.3 parts by volume of silane coupling agent KH550 were dissolved in a mixed system consisting of 80 parts by volume of anhydrous ethanol and 20 parts by volume of deionized water. The mixture was stirred magnetically for 12 minutes at room temperature with a stirring speed of 300 r / min. The pH of the system was adjusted to 4 with 0.1 mol / L hydrochloric acid solution. The mixture was then pre-hydrolyzed at room temperature for 35 minutes to obtain the KH550 solution.

[0043] Take 100 parts by mass of silica sol and place it in a reaction vessel. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60°C, add 20 parts by mass of KH550 solution dropwise into the silica sol. Stir at a constant temperature for 3.5 hours, centrifuge, collect the solid phase, wash and dry to obtain KH550 modified silica sol.

[0044] Add 50.9 parts by weight of deionized water to the dispersion vessel, maintain a stirring speed of 300 rpm, and then add 0.15 parts by weight of bactericide (composed of benzisothiazolinone and chloromethylisothiazolinone in a mass ratio of 1:1), 0.22 parts by weight of antifungal agent (composed of TIO-20 and Sol EPW in a mass ratio of 2:1), and 0.75 parts by weight of propylene glycol in sequence. Stir for 8 minutes, then add 0.12 parts by weight of polyether-modified polysiloxane defoamer, 0.16 parts by weight of wetting agent (composed of sodium polycarboxylate dispersant and alkyl polyoxyethylene ether in a mass ratio of 3:1), and 2.0 parts by weight of active ingredient (this active ingredient includes 2.3 parts by weight of precipitant, 2.5 parts by weight of chelating agent, and 4.2 parts by weight of supplementing agent; the precipitant consists of 2.8 parts by weight of...). The mixture consists of sodium carbonate, 3.2 parts by weight of sodium sulfate, 0.45 parts by weight of sodium fluorosilicate, and 4.95 parts by weight of potassium phosphate; the chelating agent consists of 5.5 parts by weight of sodium gluconate, 1.3 parts by weight of potassium sodium tartrate, and 1.2 parts by weight of tetrasodium ethylenediaminetetraacetate; the supplement consists of 3.5 parts by weight of calcium formate and 1.2 parts by weight of heavy calcium carbonate with a particle size of 1100 mesh. Stirring continues for 4 minutes. Then, 38 parts by weight of organosilicon-modified polyacrylate emulsion, 2.2 parts by weight of modified halloysite nanotubes, and 4 parts by weight of KH550 modified silica sol are added, and stirring continues for 15 minutes at a speed of 700 r / min. Next, 1.5 parts by weight of film-forming aid propylene glycol butyl ether is added, and stirring continues for 8 minutes. The mixture is then filtered and discharged to obtain a high-penetration nitrate-alkali resistant coating.

[0045] Example 3 100 parts by weight of bi-glycidoxypropyl-terminated polydimethylsiloxane and 55 parts by weight of ditoluene were mixed and stirred mechanically at 350 rpm for 11 min to obtain material A. 39.2 parts by weight of acrylic acid, 0.20 parts by weight of p-hydroxyanisole, 1.15 parts by weight of triethylamine, and 55 parts by weight of ditoluene were mixed and stirred mechanically at 350 rpm for 12 min to obtain material B. Under a nitrogen atmosphere, the reaction vessel containing material A was placed in an oil bath heating device, and mechanical stirring was started at 350 rpm. The temperature was increased to 88°C at a rate of 2°C / min. Then, material B was added dropwise under reflux heating and stirring. After the addition was complete, the temperature was continued to rise to 105°C at a rate of 2°C / min and stirring was continued for 3 h. During the reaction, samples were taken to determine the acid value of the system. When the acid value of the reaction product was less than 3 mg / L... The reaction reached its endpoint when KOH / g of the product was reacted. The product was then discharged after vacuum distillation and vacuum dried for 7 hours to obtain a double-terminated acrylate polysiloxane.

[0046] Mix 55 parts by weight of butyl acrylate, 30 parts by weight of methyl methacrylate, 5 parts by weight of 2-hydroxyethyl acrylate, and 19 parts by weight of diacrylate-terminated polysiloxane. Stir at 350 rpm for 12 minutes at room temperature using mechanical stirring. Add 6 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 2:1 mass ratio) and 200 parts by weight of deionized water. Homogenize and emulsify at 8000 rpm for 8 minutes to obtain a core layer pre-emulsion, which should be prepared and used immediately. Mix 60 parts by weight of butyl acrylate, 33 parts by weight of methyl methacrylate, and 5 parts by weight of 2-hydroxyethyl acrylate. Stir at 350 rpm for 12 minutes at room temperature using mechanical stirring. Add 4 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 2:1 mass ratio) and 200 parts by weight of deionized water. Homogenize and emulsify at 8000 rpm for 8 minutes. The emulsifier was stirred for 8 minutes to obtain a shell pre-emulsion, which was prepared and used immediately. 1.5 parts by weight of 2,2'-azobis(2-methylpropanediamine) dihydrochloride were dissolved in 25 parts by weight of deionized water to obtain the initiator. 1.5 parts by weight of sodium bicarbonate and 200 parts by weight of deionized water were added to a reactor equipped with a reflux condenser and a stirrer. Stirring was started and nitrogen was introduced for protection. One-third of the total mass of the core pre-emulsion and one-sixth of the total mass of the initiator were added first, and the reactor was heated in a water bath. The temperature was increased to 80℃ at a rate of 2℃ / min. After the system showed blue light, 1 / 3 of the total mass of the remaining core layer pre-emulsion and initiator was added dropwise at a uniform rate. After the addition was completed, the temperature was maintained for 15 min to obtain the core layer emulsion. Subsequently, the shell layer pre-emulsion and the remaining initiator were added dropwise at a uniform rate to the core layer emulsion. After the addition was completed, the temperature was maintained for another 2.5 h. The pH of the system was controlled at 5 throughout the reaction. After the reaction was completed, the system was cooled to room temperature, filtered, and discharged to obtain the organosilicon-modified polyacrylate emulsion.

[0047] Mix 0.5 parts by mass of sodium poly(4-styrene sulfonate) and 100 parts by mass of deionized water at room temperature using magnetic stirring at a speed of 350 r / min for 13 min. Add 1.1 parts by mass of halloysite nanotubes and stir magnetically for 25 h. Centrifuge and collect the solid phase, washing it repeatedly with deionized water until the pH of the filtrate is neutral. Collect the lower solid product to obtain material C. Disperse 1.0 part by mass of material C in 15 parts by mass of deionized water and add 0.3 parts by mass of polydiallyldimethylammonium chloride solution. Stir for 25 h and centrifuge. Collect the solid phase and wash it repeatedly with deionized water until the pH of the filtrate is neutral. Vacuum dry at 60 °C for 12 h to obtain modified halloysite nanotubes.

[0048] Take 4.5 parts by volume of silane coupling agent KH550 and dissolve it in a mixed system consisting of 80 parts by volume of anhydrous ethanol and 20 parts by volume of deionized water. Stir the mixture magnetically for 12 minutes at room temperature with a stirring speed of 350 r / min. Adjust the pH of the system to 5 with 0.1 mol / L hydrochloric acid solution and pre-hydrolyze it at room temperature for 35 minutes to obtain KH550 solution.

[0049] 100 parts by mass of silica sol were placed in a reaction vessel. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60°C, 23 parts by mass of KH550 solution were added dropwise to the silica sol. The mixture was stirred at a constant temperature for 3.5 hours, centrifuged, and the solid phase was collected, washed, and dried to obtain KH550 modified silica sol.

[0050] Add 47.2 parts by weight of deionized water to the dispersion vessel, maintain a stirring speed of 400 rpm, and then add 0.2 parts by weight of bactericide (composed of benzisothiazolinone, chloromethylisothiazolinone, and methylisothiazolinone in a mass ratio of 1:1:2), 0.25 parts by weight of mildew inhibitor (composed of TIO-20, Sol EPW, and KP-M21 in a mass ratio of 1:1:1), and 0.8 parts by weight of propylene glycol. Stir for 10 minutes, then add 0.15 parts by weight of polyether-modified polysiloxane defoamer, 0.2 parts by weight of wetting agent (composed of sodium polycarboxylate dispersant, fatty alcohol polyoxyethylene ether, and fatty acid polyoxyethylene ester in a mass ratio of 3:1:2), and 2.2 parts by weight of active ingredient (this active ingredient includes 2.5 parts by weight of precipitant, 3 parts by weight of chelating agent, and 4.5 parts by weight of supplementing agent; the precipitant consists of 2.5 parts by weight of...). The mixture consists of sodium carbonate (3.8 parts by weight), sodium sulfate (0.5 parts by weight), sodium fluorosilicate (4.6 parts by weight), and potassium phosphate (6 parts by weight), sodium gluconate (1.5 parts by weight), potassium sodium tartrate (1.5 parts by weight), and tetrasodium ethylenediaminetetraacetate (EDTA). The supplement consists of calcium formate (4 parts by weight) and heavy calcium carbonate (1100 mesh particle size). Stirring continues for 5 minutes. Then, 40 parts by weight of silicone-modified polyacrylate emulsion, 2.5 parts by weight of modified halloysite nanotubes, and 4.5 parts by weight of KH550 modified silica sol are added. Stirring continues for 15 minutes at 700 rpm. Next, 2 parts by weight of film-forming aid (composed of dodecyl alcohol ester, propylene glycol methyl ether acetate, and propylene glycol butyl ether in a mass ratio of 2:1:1) are added. Stirring continues for 8 minutes. The mixture is then filtered and discharged to obtain a high-penetration nitrile-alkali resistant coating.

[0051] Example 4 105 parts by mass of bi-glycidoxypropyl-terminated polydimethylsiloxane and 58 parts by mass of ditoluene were mixed and stirred mechanically at 380 rpm for 13 min to obtain material A. 42 parts by mass of acrylic acid, 0.22 parts by mass of p-hydroxyanisole, 1.18 parts by mass of triethylamine, and 58 parts by mass of ditoluene were mixed and stirred mechanically at 380 rpm for 13 min to obtain material B. Under a nitrogen atmosphere, the reaction vessel containing material A was placed in an oil bath heating device, and mechanical stirring was started at 380 rpm. The temperature was increased to 88°C at a rate of 2°C / min. Then, material B was added dropwise under reflux heating and stirring. After the addition was complete, the temperature was continued to rise to 105°C at a rate of 2°C / min and stirred for 4 hours. During the reaction, samples were taken to determine the acid value of the system. When the acid value of the reaction product was less than 3 mg / L... The reaction reached its endpoint when KOH / g of the product was reacted. The product was then discharged after vacuum distillation and vacuum dried for 8 hours to obtain a double-terminated acrylate polysiloxane.

[0052] Mix 58 parts by weight of butyl acrylate, 32 parts by weight of methyl methacrylate, 5.8 parts by weight of 2-hydroxyethyl acrylate, and 20 parts by weight of diacrylate-terminated polysiloxane. Stir at 380 rpm for 13 min at room temperature using mechanical stirring. Add 6.5 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 3:1 mass ratio) and 220 parts by weight of deionized water. Homogenize at 8000 rpm for 10 min to obtain a core layer pre-emulsion, which should be prepared and used immediately. Mix 62 parts by weight of butyl acrylate, 34 parts by weight of methyl methacrylate, and 5.5 parts by weight of 2-hydroxyethyl acrylate. Stir at 380 rpm for 12 min at room temperature using mechanical stirring. Add 4.5 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 3:1 mass ratio) and 220 parts by weight of deionized water. Homogenize at 8000 rpm for 10 min to obtain a core layer pre-emulsion. Homogenize and emulsify for 10 minutes to obtain the shell pre-emulsion, which should be prepared and used immediately. Dissolve 1.8 parts by weight of 2,2'-azobis(2-methylpropanediamine) dihydrochloride in 28 parts by weight of deionized water to obtain the initiator. Add 1.8 parts by weight of sodium bicarbonate and 200 parts by weight of deionized water to a reactor equipped with a reflux condenser and a stirrer. Start stirring and purge with nitrogen. First, add 1 / 3 of the total mass of the core pre-emulsion and 1 / 6 of the total mass of the initiator, and then use a water bath. The temperature was increased to 80℃ at a rate of 2℃ / min. After the system showed blue light, 1 / 3 of the total mass of the remaining core layer pre-emulsion and initiator was added dropwise at a uniform rate. After the addition was completed, the temperature was maintained for 20 min to obtain the core layer emulsion. Subsequently, the shell layer pre-emulsion and the remaining initiator were added dropwise at a uniform rate to the core layer emulsion. After the addition was completed, the temperature was maintained for another 3 h. The pH of the system was controlled at 6 throughout the reaction. After the reaction was completed, the system was cooled to room temperature, filtered, and discharged to obtain an organosilicon-modified polyacrylate emulsion.

[0053] Mix 0.6 parts by mass of poly(4-styrene sulfonate) and 100 parts by mass of deionized water at room temperature using magnetic stirring at a speed of 380 r / min for 13 min. Add 1.18 parts by mass of halloysite nanotubes and stir magnetically for 28 h. Centrifuge and collect the solid phase, washing it repeatedly with deionized water until the pH of the filtrate is neutral. Collect the lower solid product to obtain material C. Disperse 1.0 part by mass of material C in 18 parts by mass of deionized water and add 0.35 parts by mass of polydiallyldimethylammonium chloride solution. Stir for 28 h and centrifuge. Collect the solid phase and wash it repeatedly with deionized water until the pH of the filtrate is neutral. Vacuum dry at 60 °C for 13 h to obtain modified halloysite nanotubes.

[0054] 4.8 parts by volume of silane coupling agent KH550 were dissolved in a mixture of 80 parts by volume of anhydrous ethanol and 20 parts by volume of deionized water. The mixture was stirred magnetically for 12 minutes at room temperature with a stirring speed of 380 r / min. The pH of the system was adjusted to 5 with 0.1 mol / L hydrochloric acid solution. The mixture was then pre-hydrolyzed at room temperature for 40 minutes to obtain the KH550 solution.

[0055] Take 100 parts by mass of silica sol and place it in a reaction vessel. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60°C, add 25 parts by mass of KH550 solution dropwise into the silica sol. Stir at a constant temperature for 4 hours, centrifuge to separate, collect the solid phase, wash and dry to obtain KH550 modified silica sol.

[0056] Add 43.22 parts by weight of deionized water to the dispersion vessel, maintain a stirring speed of 500 rpm, and then add 0.25 parts by weight of bactericide methylisothiazolinone, 0.25 parts by weight of antifungal agent KP-M21, and 0.85 parts by weight of propylene glycol in sequence. Stir for 10 minutes, then add 0.18 parts by weight of polyether-modified polysiloxane defoamer, 0.25 parts by weight of wetting agent fatty acid polyoxyethylene ester, and 2.4 parts by weight of active component (this active component includes 2.8 parts by weight of precipitant, 3.5 parts by weight of chelating agent, and 4.8 parts by weight of supplementing agent; the precipitant consists of 2.8 parts by weight of sodium carbonate, 4.5 parts by weight of sodium sulfate, 0.55 parts by weight of sodium fluorosilicate, and 5.5 parts by weight of sodium carbonate). The composition is potassium phosphate; the chelating agent consists of 6.2 parts by weight of sodium gluconate, 1.7 parts by weight of potassium sodium tartrate, and 1.8 parts by weight of tetrasodium ethylenediaminetetraacetate; the supplement consists of 4.5 parts by weight of calcium formate and 1.18 parts by weight of heavy calcium carbonate with a particle size of 1200 mesh), and stirring is continued for 5 min; then 42 parts by weight of organosilicon modified polyacrylate emulsion, 2.8 parts by weight of modified halloysite nanotubes, and 5.2 parts by weight of KH550 modified silica sol are added, and stirring is continued for 20 min at a speed of 800 r / min. Then 2.6 parts by weight of film-forming aid propylene glycol methyl ether acetate are added, and stirring is continued for 10 min. After filtration, the material is discharged to obtain a high-penetration nitrate-alkali resistant coating.

[0057] Example 5 110 parts by weight of bi-glycidoxypropyl-terminated polydimethylsiloxane and 60 parts by weight of ditoluene were mixed and stirred mechanically at 400 rpm for 15 min to obtain material A. 45 parts by weight of acrylic acid, 0.25 parts by weight of p-hydroxyanisole, 1.2 parts by weight of triethylamine, and 60 parts by weight of ditoluene were mixed and stirred mechanically at 400 rpm for 12 min to obtain material B. Under a nitrogen atmosphere, the reaction vessel containing material A was placed in an oil bath heating device, and mechanical stirring was started at 400 rpm. The temperature was increased to 90°C at a rate of 2.5°C / min. Then, material B was added dropwise under reflux heating and stirring. After the addition was complete, the temperature was continued to rise to 105°C at a rate of 2.5°C / min and stirring was continued for 4 h. During the reaction, samples were taken to determine the acid value of the system. When the acid value of the reaction product was less than 3 mg / L... The reaction reached its endpoint when KOH / g of the product was reacted. The product was then discharged after vacuum distillation and vacuum dried for 8 hours to obtain a double-terminated acrylate polysiloxane.

[0058] Mix 60 parts by weight of butyl acrylate, 35 parts by weight of methyl methacrylate, 6 parts by weight of 2-hydroxyethyl acrylate, and 22 parts by weight of diacrylate-terminated polysiloxane. Stir at 400 rpm for 13 min at room temperature using mechanical stirring. Add 7 parts by weight of emulsifier (composed of hexadecyltrimethylammonium chloride and Span-80 in a 3:1 mass ratio) and 250 parts by weight of deionized water. Homogenize and emulsify at 8000 rpm for 10 min to obtain a core layer pre-emulsion, which should be prepared and used immediately. Mix 65 parts by weight of butyl acrylate, 35 parts by weight of methyl methacrylate, and 6 parts by weight of 2-hydroxyethyl acrylate. Stir at 400 rpm for 14 min at room temperature using mechanical stirring. Add 5 parts by weight of emulsifier and 250 parts by weight of deionized water. Homogenize and emulsify at 8000 rpm for 10 min to obtain... The shell pre-emulsion was prepared fresh for immediate use. Two parts by mass of 2,2'-azobis(2-methylpropanediamine) dihydrochloride were dissolved in 30 parts by mass of deionized water to obtain the initiator. Two parts by mass of sodium bicarbonate and 200 parts by mass of deionized water were added to a reactor equipped with a reflux condenser and a stirrer. The stirring was turned on and nitrogen was introduced for protection. First, 1 / 3 of the total mass of the core pre-emulsion and 1 / 6 of the total mass of the initiator were added. The temperature was raised to 80°C at a rate of 2°C / min using a water bath. After the system showed a blue light, the remaining core pre-emulsion and 1 / 3 of the total mass of the initiator were added dropwise at a uniform rate. After the addition was completed, the temperature was maintained for 20 minutes to obtain the core emulsion. Subsequently, the shell pre-emulsion and the remaining initiator were added dropwise at a uniform rate to the core emulsion. After the addition was completed, the temperature was maintained for another 3 hours. The pH of the system was controlled at 6 throughout the reaction. After the reaction was completed, the mixture was cooled to room temperature, filtered, and discharged to obtain an organosilicon-modified polyacrylate emulsion.

[0059] Mix 0.7 parts by mass of poly(4-styrene sulfonate) and 100 parts by mass of deionized water at room temperature using magnetic stirring at a speed of 400 r / min for 12 min. Add 1.2 parts by mass of halloysite nanotubes and stir magnetically for 30 h. Centrifuge and collect the solid phase, washing it repeatedly with deionized water until the pH of the filtrate is neutral. Collect the lower solid product to obtain material C. Disperse 1.0 part by mass of material C in 20 parts by mass of deionized water and add 0.4 parts by mass of polydiallyldimethylammonium chloride solution. Stir for 30 h and centrifuge. Collect the solid phase and wash it repeatedly with deionized water until the pH of the filtrate is neutral. Vacuum dry at 60 °C for 15 h to obtain modified halloysite nanotubes.

[0060] Take 5 volumes of silane coupling agent KH550 and dissolve it in a mixed system consisting of 80 volumes of anhydrous ethanol and 20 volumes of deionized water. Stir the mixture magnetically for 10 minutes at room temperature with a stirring speed of 350 r / min. Adjust the pH of the system to 5 with 0.1 mol / L hydrochloric acid solution and pre-hydrolyze at room temperature for 40 minutes to obtain KH550 solution.

[0061] Take 100 parts by mass of silica sol and place it in a reaction vessel. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60°C, add 27 parts by mass of KH550 solution dropwise into the silica sol. Stir at a constant temperature for 4 hours, centrifuge to separate, collect the solid phase, wash and dry to obtain KH550 modified silica sol.

[0062] Add 38.4 parts by weight of deionized water to the dispersion vessel, maintain a stirring speed of 500 rpm, and then add 0.3 parts by weight of bactericide chloromethylisothiazolinone, 0.3 parts by weight of antifungal agent KP-M21, and 0.9 parts by weight of propylene glycol in sequence. Stir for 10 minutes, then add 0.2 parts by weight of polyether-modified polysiloxane defoamer, 0.3 parts by weight of wetting agent fatty acid polyoxyethylene ester, and 2.6 parts by weight of active component (this active component includes 3 parts by weight of precipitant, 4 parts by weight of chelating agent, and 5 parts by weight of supplementing agent; the precipitant consists of 3 parts by weight of sodium carbonate, 5 parts by weight of sodium sulfate, 0.6 parts by weight of sodium fluorosilicate, and 6 parts by weight of sodium carbonate). The mixture consists of potassium phosphate; the chelating agent consists of 7 parts by mass of sodium gluconate, 2 parts by mass of potassium sodium tartrate, and 2 parts by mass of tetrasodium ethylenediaminetetraacetate; the supplement consists of 5 parts by mass of calcium formate and 2 parts by mass of heavy calcium carbonate with a particle size of 1200 mesh. Stirring continues for 5 minutes. Then, 45 parts by mass of organosilicon-modified polyacrylate emulsion, 3 parts by mass of modified halloysite nanotubes, and 6 parts by mass of KH550-modified silica sol are added. Stirring continues for 20 minutes at a speed of 800 r / min. Then, 3 parts by mass of film-forming aid propylene glycol butyl ether is added, and stirring continues for 10 minutes. The mixture is filtered and discharged to obtain a high-penetration nitrate-alkali resistant coating.

[0063] Comparative Example 1 The difference from Example 3 is that the halloysite nanotubes in this high-penetration nitrate-alkali resistant coating have not undergone surface electrostatic assembly modification treatment, while the remaining operations and dosages remain unchanged.

[0064] Comparative Example 2 The difference from Example 3 is that the silica sol in this high-penetration nitrate-alkali resistant coating has not been modified by KH550, while the other operations and dosages remain unchanged.

[0065] Comparative Example 3 The difference from Example 3 is that the supplement in this high-penetration nitrate-alkali resistant coating is only calcium formate, while the rest of the operation and dosage remain unchanged.

[0066] Performance testing The coatings prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests: 1) Alkali resistance (168h): Refer to standard JG / T 26-2002; 2) Anti-efflorescence: Refer to standard JG / T 210-2018; 3) Anti-nitrification: High-salt cement mortar test blocks were prepared (cement, standard sand, water, and sodium nitrate were mixed in a mass ratio of 1:3:0.5:0.15), with a block size of 70mm×70mm×20mm, and cured under standard conditions for 7 days; dried at 50℃ to constant weight; and coated with the coatings prepared in Examples 1-5 and Comparative Examples 1-3 on one side, with a coating amount of 100g / m². 2 The coating was cured under standard conditions for 48 hours; the coated sample was completely immersed in 23°C water for 16 hours; after being removed, it was placed in a 50°C oven and dried for 8 hours; after being removed and cooled to room temperature, the surface of the sample was observed for nitrification, whitening, and crystallization; after 3 cycles, the final result was evaluated according to the grade.

[0067] Rating: Grade 0: No nitrification, no whitening, no crystallization; Grade 1: Slight traces, not affecting appearance; Grade 2: Obvious whitening, visible crystallization; Grade 3: Severe whitening, large area of ​​crystallization.

[0068] 4) Penetration depth: Refer to standard JG / T 210-2018; 5) Water vapor transmission rate: Refer to standard GB / T 17146-2015; 6) Antibacterial rate of Escherichia coli and antibacterial rate of Staphylococcus aureus: Refer to standard GB / T 21866-2008; 7) Mildew resistance rating: Refer to standard GB / T 1741-2007; The test results are shown in Table 1.

[0069] Table 1 Comprehensive performance test results

[0070] The test results above show that: The high-penetration nitrate-alkali resistant coatings prepared in Examples 1-5 of this invention have comprehensive advantages such as high penetration, strong alkali resistance, anti-nitrification, high sealing, high weather resistance, and antibacterial and antifungal properties.

[0071] Comparative Example 1 did not undergo stepwise electrostatic self-assembly modification of halloysite nanotubes, resulting in a significant decrease in adsorption and dispersion properties, as well as a substantial reduction in alkali and nitrate resistance, antibacterial properties, and antifungal properties.

[0072] Comparative Example 2 did not use KH550 modified silica sol, resulting in insufficient coating compatibility, density, and sealing properties, and significantly reduced resistance to alkali and nitrate, as well as antibacterial and antifungal properties.

[0073] Comparative Example 3, which did not contain heavy calcium carbonate, had insufficient filling and sealing effect, resulting in a decrease in coating density, alkali and nitrate resistance, and antibacterial and antifungal properties.

[0074] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, features in the embodiments of the present invention can be combined with each other unless otherwise specified.

Claims

1. A method for preparing a high-penetration nitrate-alkali resistant coating, characterized in that, Includes the following steps: Add bactericide, mildew inhibitor, propylene glycol, defoamer, wetting agent, active ingredient, organosilicon modified polyacrylate emulsion, modified halloysite nanotubes, KH550 modified silica sol and film-forming aid to deionized water in sequence. After stirring evenly, filter and discharge to obtain the high-penetration nitrate-alkali resistant coating. The modified halloysite nanotubes were prepared by stepwise electrostatic self-assembly of poly(sodium 4-styrene sulfonate) and polydiallyl dimethyl ammonium chloride to modify the inner and outer surfaces of the halloysite nanotubes.

2. The method for preparing a high-penetration nitrate-alkali resistant coating according to claim 1, characterized in that, The preparation method of the organosilicon-modified polyacrylate emulsion includes the following steps: A1. Under a nitrogen atmosphere, take the double-ended epoxypropoxypropyl polydimethylsiloxane and toluene and mix them evenly. Under reflux heating and stirring, add the mixture of acrylic acid, p-hydroxyanisole, triethylamine and toluene. Heat and stir, distill under reduced pressure, discharge the material and dry under vacuum to obtain double-ended acrylate polysiloxane. A2. Under a nitrogen atmosphere, sodium bicarbonate, deionized water, 1 / 3 of the total mass of the core layer pre-emulsion, and 1 / 6 of the total mass of the initiator are mixed under reflux and stirring. The mixture is heated to react. After the system shows blue light, the remaining core layer pre-emulsion and 1 / 3 of the total mass of the initiator are added dropwise. The mixture is kept at this temperature to obtain a core layer emulsion. Then, the shell layer pre-emulsion and the remaining initiator are added dropwise. The mixture is kept at this temperature, and the pH of the system is controlled to be 5-6. After the reaction is completed, the mixture is cooled, filtered, and discharged to obtain the organosilicon-modified polyacrylate emulsion.

3. The method for preparing a high-penetration nitrate-alkali resistant coating according to claim 2, characterized in that, In step A1, the mass ratio of the double-sided epoxypropoxypropyl-terminated polydimethylsiloxane, toluene, acrylic acid, p-hydroxyanisole, triethylamine, and ditoluene is 100:50:39.2:0.2:1.0:

50.

4. The preparation method of a high-penetration nitrate-alkali resistant coating according to claim 2, characterized in that, In step A2, the core layer pre-emulsion is prepared by homogenizing and emulsifying butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, diacrylate-terminated polysiloxane, emulsifier, and deionized water; the mass ratio of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, diacrylate-terminated polysiloxane, emulsifier, and deionized water is 50-60:25-35:4-6:15-22:5-7:150-250.

5. The method for preparing a high-penetration nitrate-alkali resistant coating according to claim 2, characterized in that, In step A2, the shell pre-emulsion is prepared by homogenizing and emulsifying butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, emulsifier, and deionized water; the mass ratio of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, emulsifier, and deionized water is 55-65:30-35:4-6:3-5:150-250.

6. The method for preparing a high-penetration nitrate-alkali resistant coating according to claim 2, characterized in that, The initiator is prepared by dissolving 2,2'-azobis(2-methylpropanediamine) dihydrochloride in deionized water; the mass ratio of 2,2'-azobis(2-methylpropanediamine) dihydrochloride to deionized water is 1-2:20-30.

7. The method for preparing a high-penetration nitrate-alkali resistant coating according to claim 1, characterized in that, The preparation method of the KH550 modified silica sol includes the following steps: B1. Dissolve silane coupling agent KH550 in a mixture of anhydrous ethanol and deionized water, stir until homogeneous, adjust the pH of the system to 4-5, and pre-hydrolyze at room temperature to obtain KH550 solution; the volume ratio of silane coupling agent KH550, anhydrous ethanol and deionized water is 4-5:80:

20. B2. Under the conditions of heating, condensing, refluxing and stirring in a water bath at 60℃, the KH550 solution is added dropwise to the silica sol, stirred at a constant temperature, centrifuged, the solid phase is collected, washed, and dried to obtain KH550 modified silica sol; the ratio of silica sol to KH550 solution is 100g:20-30mL.

8. A high-penetration nitrate-alkali resistant coating, characterized in that, The coating is prepared using the preparation method of any one of claims 1-7, wherein the mass ratio of deionized water, bactericide, mildew inhibitor, propylene glycol, defoamer, wetting agent, active ingredient, organosilicon-modified polyacrylate emulsion, modified halloysite nanotubes, KH550 modified silica sol and film-forming aid is 38.4-56:0.1-0.3:0.2-0.3:0.7-0.9:0.1-0.2:0.1-0.3:1.8-2.6:35-45:2-3:3-6:1-3.

9. The high-penetration nitrate-alkali resistant coating according to claim 8, characterized in that, The active components include precipitants, chelating agents, and supplements; the bactericides include at least one of benzisothiazolinone, chloromethylisothiazolinone, and methylisothiazolinone; the antifungal agents include at least one of TiO-20, Sol EPW, and KP-M21; the defoamers are polyether-modified polysiloxane defoamers; the wetting agents include at least one of sodium polycarboxylate dispersants, alkyl polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, and fatty acid polyoxyethylene esters; and the film-forming aids include at least one of alcohol ester dodecyl, propylene glycol methyl ether acetate, and propylene glycol butyl ether.

10. A high-penetration nitrate-alkali resistant coating according to claim 9, characterized in that, The mass ratio of the precipitant, chelating agent, and supplement is 2-3:2-4:4-5; the precipitant includes at least one of sodium carbonate, sodium sulfate, sodium fluorosilicate, and potassium phosphate; the chelating agent includes at least one of sodium gluconate, potassium sodium tartrate, and tetrasodium ethylenediaminetetraacetate; the supplement includes calcium formate and heavy calcium carbonate; the mass ratio of calcium formate to heavy calcium carbonate is 3-5:1-2; the particle size of the heavy calcium carbonate is 1000-1200 mesh.

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