Waterproofed and brushed exterior wall latex paint and preparation method thereof

Abstract

This invention discloses a waterproof textured exterior wall latex paint and its preparation method. The waterproof textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: water 8.5-15.2 parts, antifreeze 10-14 parts, dispersant 0.8-1.2 parts, wetting agent 0.2-0.4 parts, defoamer 0.8-1.2 parts, titanium dioxide 19-25 parts, barium sulfate 10-15 parts, heavy calcium carbonate 10-15 parts, cellulose 0.1-0.3 parts, pH adjuster... The mixture comprises 0.1-0.3 parts of a solvent, 0.4-0.8 parts of a bactericide, 37-40 parts of a waterproof emulsion, 4-8 parts of a waterborne polyurethane dispersion, 0.5-1 parts of an opaque polymer, 1.0-1.4 parts of a thickener diluent, 0.01-0.05 parts of a leveling agent, 3.5-5.2 parts of pH-responsive nano-SiO2 aerogel microspheres, and 1.8-2.5 parts of a dynamic silicone ester crosslinking agent; the thickener diluent is prepared by mixing thickener and water in a 1:1 mass ratio. This invention constructs a "spatiotemporally separated dual-functional system" by introducing pH-responsive nano-SiO2 aerogel microspheres and a dynamic silicone ester crosslinking agent, thereby enhancing the textured surface and waterproof performance during the construction and curing periods respectively, achieving a synergistic improvement in both properties.

Description

Technical Field

[0001] This application relates to the field of architectural coatings technology, and in particular to a waterproof textured exterior wall latex paint and its preparation method. Background Technology

[0002] Exterior textured latex paint needs to simultaneously satisfy excellent three-dimensional decorative effect (clear and durable textured texture) and long-term waterproof and weather-resistant performance. Existing technologies typically achieve the textured effect by adding thickeners and aggregates, and improve waterproofing through elastic emulsions, but it is often difficult to achieve both simultaneously. For example, the water-resistant elastic architectural coating disclosed in CN114213968A focuses on improving water resistance through elastic emulsions, but does not address the problem of the textured texture easily leveling and collapsing in humid environments, resulting in insufficient texture retention. The energy-saving and environmentally friendly interior wall paint disclosed in CN104962186B, although using polyurethane dispersions and opaque polymers, is applied to interior walls and does not consider the synergistic issue of waterproofing and texture durability in harsh exterior wall environments.

[0003] The common shortcomings of current exterior wall textured latex paints are: 1) During construction, high thixotropy is required to ensure the textured effect, but high thixotropy contradicts the leveling and film density of the paint, often resulting in unclear texture or reduced waterproof performance; 2) After curing, the waterproof network of the coating is static and singular. Under high humidity freeze-thaw cycles, microcracks are prone to occur and propagate, leading to waterproof failure and texture damage. Therefore, developing an intelligent collaborative system for exterior wall textured latex paint that can achieve "precise texture locking during construction and dynamic long-term waterproofing during curing" is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] In view of this, this application provides a waterproof textured exterior wall latex paint and its preparation method. The latex paint constructs a "spatiotemporally separated dual-function system" by introducing pH-responsive nano-SiO2 aerogel microspheres and dynamic silicone ester crosslinking agent, thereby enhancing the textured effect and waterproof performance during the construction and curing periods, respectively, and achieving a synergistic improvement in the performance of both.

[0005] To achieve the above objectives, this application employs the following technical solution:

[0006] A waterproof, textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: water 8.5-15.2 parts, antifreeze 10-14 parts, dispersant 0.8-1.2 parts, wetting agent 0.2-0.4 parts, defoamer 0.8-1.2 parts, titanium dioxide 19-25 parts, barium sulfate 10-15 parts, heavy calcium carbonate 10-15 parts, cellulose 0.1-0.3 parts, pH adjuster 0.1-0.3 parts. The composition includes 0.4-0.8 parts bactericide, 37-40 parts waterproof emulsion, 4-8 parts waterborne polyurethane dispersion, 0.5-1 parts opaque polymer, 1.0-1.4 parts thickener diluent, 0.01-0.05 parts leveling agent, 3.5-5.2 parts pH-responsive nano-SiO2 aerogel microspheres, and 1.8-2.5 parts dynamic silicone ester crosslinking agent; the thickener diluent is prepared by mixing thickener and water at a mass ratio of 1:1.

[0007] Functions of each component: Water: Dispersion medium, adjusts system viscosity. Antifreeze: Lowers the freezing point of the coating, preventing demulsification due to low-temperature freeze-thaw cycles. Dispersant: Reduces the surface energy of powder particles, preventing agglomeration. Wetting agent: Reduces surface tension, improves wettability. Defoamer: Inhibits bubble formation during production and application. Titanium dioxide paste: Provides high hiding power and whiteness, shields against ultraviolet rays. Barium sulfate and heavy calcium carbonate: Extender fillers, improve coating film hardness and fullness. pH adjuster: Stabilizes the system pH value, ensuring emulsion stability. Bactericide: Inhibits bacterial growth, extends shelf life. Waterproof emulsion: Film-forming matrix, provides basic waterproofing and adhesion. Waterborne polyurethane dispersion: Improves coating film toughness, weather resistance, and crosslinking density. Opaque polymer: Improves hiding power, reduces titanium dioxide usage. Thickener diluent: Adjusts system thixotropy, ensuring smooth application. Leveling agent: Improves coating surface smoothness, reduces brush marks. pH-responsive nano-SiO2 aerogel microspheres: During construction, they build a thixotropic framework, enhancing the clarity of the textured surface; during curing, they physically block moisture, improving water resistance. Dynamic silicone ester crosslinking agent: During curing, it forms a dynamic covalent crosslinking network, improving water resistance and the ability to self-heal microcracks. Cellulose: It assists in thickening and synergistically contributes to the construction of the thixotropic network in the aerogel.

[0008] Core collaboration mechanism:

[0009] (1) Construction stage (alkaline environment, pH≈8.8): The abundant silanol groups on the surface of pH-responsive nano-SiO2 aerogel microspheres and the cellulose in the system form a three-dimensional network structure through hydrogen bonding, which constitutes a thixotropic enhancement skeleton, greatly improving the thixotropy of the coating (thixotropic index reaches 3.2-3.5), making the texture stand up and clear during the roughening process, and it is not easy to drip after construction, with clear texture.

[0010] (2) Curing stage (pH naturally drops to 7.5-8.0, moisture evaporates): The dynamic silicone ester crosslinking agent begins to hydrolyze and undergoes a condensation reaction with the hydroxyl groups in the waterproof emulsion, waterborne polyurethane dispersion and the silanol groups on the surface of pH-responsive nano-SiO2 aerogel microspheres, forming a dynamic covalent bond network of Si-O-Si and Si-OC. This dynamic crosslinking network not only firmly crosslinks the components such as pH-responsive nano-SiO2 aerogel microspheres to build a waterproof and dense layer, giving the coating high hydrophobicity (contact angle 118-125°) and impermeability (i.e., impermeability: 0.3MPa, impermeable for 180min); its "dynamic" characteristics also give the coating 15-20% reversible deformation ability, which can repair microcracks.

[0011] (3) Synergistic effect: The nanoporous structure of pH-responsive nano-SiO2 aerogel microspheres captures air in the coating to form an "air cushion layer" that physically blocks water vapor. The dynamic cross-linking network provides a chemical barrier and self-healing ability. The two work together to enable the coating to retain a texture rate of up to 94% even after being placed in an extremely high humidity environment (RH 95%) for 6 months, which is far superior to ordinary textured coatings.

[0012] Specifically, the dynamic siloxane crosslinking agent is an aminosilane-terminated alkoxysilane crosslinking agent;

[0013] Specifically, the pH-responsive nano-SiO2 aerogel microspheres have a particle size of 800-1200 nm and a specific surface area ≥600 m². 2 / g, in which the volume of mesopores of 2-8nm accounts for 64-66%, and the volume of macropores of 50-200nm accounts for 29-31%.

[0014] Specifically, the antifreeze is propylene glycol; the dispersant is a polycarboxylate dispersant; the wetting agent is a nonionic surfactant; the defoamer is one or more of organosilicon defoamers or mineral oil defoamers in any proportion; the pH adjuster is 2-amino-2-methyl-1-propanol; the bactericide is an isothiazolinone bactericide; the waterproof emulsion is an acrylate emulsion; the aqueous polyurethane dispersion is an aliphatic polyurethane dispersion; the opaque polymer is acrylic polymer microspheres; the thickener is a polyurethane thickener; the leveling agent is polyether-modified polydimethylsiloxane; and the cellulose is hydroxyethyl cellulose.

[0015] Specifically, the titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 20-40 parts water, 0.1-0.3 parts cellulose, 0.5-0.7 parts dispersant, 0.2-0.4 parts wetting agent, 0.1-0.3 parts defoamer, 0.2-0.4 parts bactericide, 0.2-0.3 parts pH adjuster, 45-55 parts titanium dioxide with a particle size of 200-400 nm, and 5-15 parts titanium dioxide with a particle size of 10-50 nm.

[0016] Titanium dioxide paste provides basic hiding power, stability, and UV shielding capabilities. The roles of each component in titanium dioxide paste are as follows: Water: dispersion medium; Cellulose: aids dispersion and stabilizes the paste; Dispersant, wetting agent, and defoamer: ensure uniform dispersion of titanium dioxide, preventing agglomeration and bubbles; pH adjuster: stabilizes the pH value of the paste; Bactericide: prevents mold growth; Titanium dioxide with a particle size of 200-400 nm: provides primary hiding power; Titanium dioxide with a particle size of 10-50 nm: refines the particle size, improving hiding efficiency and UV shielding capabilities.

[0017] Specifically, the preparation method of the titanium dioxide slurry includes the following steps: adding water to a reaction vessel, continuing to add cellulose at a speed of 300-500 rpm, and stirring for 1-2 minutes; then adding defoamer, wetting agent, dispersant and pH adjuster, and stirring for 2-3 minutes; then adjusting the speed to 800-1000 rpm, adding titanium dioxide powder with a particle size of 200-400 nm and titanium dioxide powder with a particle size of 10-50 nm, and stirring until uniform; then adjusting the speed to 1300-1500 rpm, and stirring for 12-15 minutes until the fineness of the slurry is ≤50 μm; finally adding bactericide, stirring evenly, and obtaining titanium dioxide slurry.

[0018] Specifically, in titanium dioxide paste: the dispersant is a polycarboxylate dispersant; the wetting agent is a nonionic surfactant; the defoamer is one or more of organosilicon defoamers or mineral oil defoamers in any proportion; the pH adjuster is 2-amino-2-methyl-1-propanol; the bactericide is an isothiazolinone bactericide; and the cellulose is hydroxyethyl cellulose.

[0019] This invention also provides a method for preparing the above-mentioned waterproof textured exterior wall latex paint, comprising the following steps:

[0020] a. Pre-dispersion: 3.5-5.2 parts of pH-responsive nano-SiO2 aerogel microspheres are pre-dispersed in 3.5-5.2 parts of water, with a mass ratio of pH-responsive nano-SiO2 aerogel microspheres to water of 1:1. The mixture is then dispersed at a shear rate of 1800-2000 rpm for 15-20 min to obtain aerogel pre-dispersion slurry.

[0021] b. Slurry dispersion: First, add 5-10 parts of water to the reactor, adjust the rotation speed to 400-500 rpm, then add 10-14 parts of antifreeze, 0.8-1.2 parts of dispersant, 0.2-0.4 parts of wetting agent, 0.8-1.2 parts of defoamer, and 19-25 parts of titanium dioxide slurry in sequence, and stir for 3-5 minutes; then increase the rotation speed to 800-1000 rpm, add 10-15 parts of barium sulfate and 10-15 parts of heavy calcium carbonate, and disperse for 5-10 minutes; then add 0.1-0.3 parts of cellulose, and disperse for 5-10 minutes; then add 0.1-0.3 parts of pH adjuster to adjust the pH of the system to 8.6-9; then adjust the rotation speed to 1000-1500 rpm, and disperse at high speed for 15-20 minutes until the detection fineness is ≤50μm;

[0022] c. Paint Mixing and Curing: After the slurry is dispersed, adjust the rotation speed to 500-1000 rpm, and add 0.4-0.8 parts of bactericide, 37-40 parts of waterproof emulsion, 4-8 parts of waterborne polyurethane dispersion, 0.5-1 parts of opaque polymer, the aerogel pre-dispersion slurry prepared in step a, 1.0-1.4 parts of thickener diluent and 0.01-0.05 parts of leveling agent in sequence. Finally, add 1.8-2.5 parts of dynamic silicone ester crosslinking agent. After the addition is complete, continue to disperse for 10-15 minutes until the system is evenly mixed to obtain waterproof textured exterior wall latex paint.

[0023] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0024] (1) Excellent textured effect and construction performance: The waterproof textured exterior wall latex paint of the present invention uses pH-responsive nano-SiO2 aerogel microspheres and cellulose. During the construction stage, the abundant silanol groups on the surface of the pH-responsive nano-SiO2 aerogel microspheres and the cellulose in the system form a three-dimensional network structure through hydrogen bonding, which constitutes a thixotropic enhancement skeleton and greatly improves the thixotropy of the paint (thixotropic index as high as 3.2-3.5). This makes the texture stand up and clear during the textured construction, and it is not easy to drip after construction. The texture is clear, which effectively improves the anti-drip and texture shaping ability of the paint during construction.

[0025] (2) Excellent waterproof performance: The waterproof roughened exterior wall latex paint of the present invention uses a dynamic silicone ester crosslinking agent. During the curing stage, the dynamic silicone ester crosslinking agent begins to hydrolyze and undergoes a condensation reaction with the hydroxyl groups in the waterproof emulsion, the waterborne polyurethane dispersion, and the silanol groups on the surface of the pH-responsive nano-SiO2 aerogel microspheres to form a dynamic covalent bond network of Si-O-Si and Si-OC. This dynamic crosslinking network not only firmly crosslinks the components such as aerogel microspheres to build a dense hydrophobic film, giving the coating film high hydrophobicity (contact angle 118-125°), impermeability (0.3MPa, impermeable for 180min) and water resistance (no abnormality in 96h immersion test), but also the "dynamic" characteristics give the coating microcracks self-healing potential.

[0026] (3) Excellent weather resistance and durability: The waterproof textured exterior wall latex paint of the present invention uses titanium dioxide with a particle size of 10-50nm and aerogel microspheres to provide ultraviolet shielding. It can withstand artificial aging for 500h without chalking and discoloration ≤ Grade 1. In addition, the nanoporous structure of pH-responsive nano-SiO2 aerogel microspheres captures air in the coating to form an "air cushion layer", which physically blocks water vapor. The dynamic cross-linking network provides a chemical barrier and self-healing ability. The two work together to make the texture retention rate of the coating reach up to 94% after 6 months in an extreme high humidity environment (RH 95%), which is far superior to ordinary textured coatings and overcomes the defect of traditional textured coatings that are easy to soften in high humidity environments.

[0027] (4) The waterproof textured exterior wall latex paint of this application has a coating adhesion (cross-cut test) that can reach the highest level 0.

[0028] (5) The waterproof textured exterior wall latex paint of this application is a water-based system with low VOC content, which meets the green building standard and is environmentally friendly and safe.

[0029] (6) The preparation process of the waterproof textured exterior wall latex paint of this application is reliable, the process steps are clear, and the key parameters (such as pH value and aerogel pre-dispersion) are controllable, making it suitable for industrial production. Detailed Implementation

[0030] The exemplary embodiments of the present invention are described in more detail below. These embodiments are intended to provide a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. While exemplary embodiments of the present invention are shown, it should be understood that the invention should not be limited to the embodiments set forth herein.

[0031] All raw materials used in this invention are commercially available products, wherein:

[0032] The dynamic siloxane crosslinking agent is an aminosilane-terminated alkoxysilane crosslinking agent;

[0033] The pH-responsive nano-SiO2 aerogel microspheres have a particle size of 800-1200 nm and a specific surface area ≥600 m². 2 / g, its pore structure has a proportion of 64-66% of mesopores (2-8nm) and 29-31% of macropores (50-200nm);

[0034] The thickener dilution is prepared by mixing thickener and water at a mass ratio of 1:1.

[0035] The antifreeze is propylene glycol; the dispersant is a polycarboxylate dispersant; the wetting agent is a nonionic surfactant; the pH adjuster is 2-amino-2-methyl-1-propanol; the bactericide is an isothiazolinone bactericide; the waterproof emulsion is an acrylate emulsion; the aqueous polyurethane dispersion is an aliphatic polyurethane dispersion; the opaque polymer is acrylic polymer microspheres; the thickener is a polyurethane thickener; the leveling agent is polyether-modified polydimethylsiloxane; and the cellulose is hydroxyethyl cellulose.

[0036] Example 1

[0037] A waterproof textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: 8.5 parts water, 10 parts antifreeze, 0.8 parts dispersant, 0.2 parts wetting agent, 0.8 parts silicone defoamer, 19 parts titanium dioxide paste, 10 parts barium sulfate, 10 parts heavy calcium carbonate, 0.1 parts cellulose, 0.1 parts pH adjuster, 0.4 parts bactericide, 37 parts waterproof emulsion, 4 parts waterborne polyurethane dispersion, 0.5 parts opaque polymer, 1.0 part thickener diluent, 0.01 parts leveling agent, 3.5 parts pH-responsive nano-SiO2 aerogel microspheres, and 1.8 parts dynamic silicone ester crosslinking agent.

[0038] The titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 20 parts water, 0.1 parts cellulose, 0.5 parts dispersant, 0.2 parts wetting agent, 0.1 parts silicone defoamer, 0.2 parts bactericide, 0.2 parts pH adjuster, 45 parts titanium dioxide with a particle size of 200-400nm, and 5 parts titanium dioxide with a particle size of 10-50nm.

[0039] Preparation steps:

[0040] (1) Preparation of titanium dioxide slurry: Add water to the reactor, add cellulose at 300 rpm and stir for 1 min; then add dispersant, wetting agent, organosilicon defoamer and pH adjuster and stir for 2 min; then adjust the speed to 800 rpm, add titanium dioxide with a particle size of 200-400 nm and titanium dioxide with a particle size of 10-50 nm and stir until uniform; then adjust the speed to 1300 rpm and stir for 12 min until the fineness of the slurry is ≤50 μm; finally add bactericide and stir evenly to obtain titanium dioxide slurry.

[0041] (2) Preparation of waterproof textured exterior wall latex paint:

[0042] a. Pre-dispersion: 3.5 parts of pH-responsive nano-SiO2 aerogel microspheres were pre-dispersed in a portion (3.5 parts) of water and dispersed at high speed at 1800 rpm for 15 minutes to prepare aerogel pre-dispersion slurry;

[0043] b. Slurry dispersion: First, add the remaining (5 parts) water to the reactor, adjust the speed to 400 rpm, then add the antifreeze, dispersant, wetting agent, silicone defoamer and titanium dioxide slurry in sequence, and stir for 3 min; then increase the speed to 800 rpm, add barium sulfate and heavy calcium carbonate, and disperse for 5 min; then add cellulose, disperse for 5 min, add pH adjuster, and adjust the pH of the system to 8.6; then increase the speed to 1000 rpm, disperse at high speed for 15 min, and check the fineness ≤50μm;

[0044] c. Paint Mixing and Curing: After the slurry is dispersed, reduce the rotation speed to 500 rpm, and add the bactericide, waterproof emulsion, waterborne polyurethane dispersion, opaque polymer, aerogel pre-dispersion slurry prepared in step a, thickener diluent, and leveling agent in sequence. Finally, slowly add the dynamic silicone ester crosslinking agent. After all the materials are added, continue dispersing for 10 minutes until the system is uniformly mixed to obtain the waterproof textured exterior wall latex paint. After the paint is applied, cure it for 7 days at 25°C and 50%RH.

[0045] Example 2

[0046] A waterproof textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: 12.2 parts water, 12 parts antifreeze, 1.0 part dispersant, 0.3 parts wetting agent, 1.0 part silicone defoamer, 22 parts titanium dioxide paste, 12 parts barium sulfate, 12 parts heavy calcium carbonate, 0.15 parts cellulose, 0.2 parts pH adjuster, 0.6 parts bactericide, 38.5 parts waterproof emulsion, 6 parts waterborne polyurethane dispersion, 0.75 parts opaque polymer, 1.2 parts thickener diluent, 0.03 parts leveling agent, 4.2 parts pH-responsive nano-SiO2 aerogel microspheres, and 2.0 parts dynamic silicone ester crosslinking agent.

[0047] The titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 30 parts water, 0.2 parts cellulose, 0.6 parts dispersant, 0.3 parts wetting agent, 0.2 parts mineral oil defoamer, 0.3 parts bactericide, 0.25 parts pH adjuster, 50 parts titanium dioxide with a particle size of 200-400nm, and 10 parts titanium dioxide with a particle size of 10-50nm.

[0048] Preparation steps:

[0049] (1) Preparation of titanium dioxide slurry: Add water to the reactor, add cellulose at 400 rpm and stir for 1.5 min; then add dispersant, wetting agent, mineral oil defoamer and pH adjuster and stir for 2.5 min; then adjust the speed to 900 rpm, add titanium dioxide with a particle size of 200-400 nm and titanium dioxide with a particle size of 10-50 nm and stir until uniform; then adjust the speed to 1400 rpm and stir for 13 min, and check the fineness of the slurry ≤50 μm; finally add bactericide and stir evenly to obtain titanium dioxide slurry.

[0050] (2) Preparation of waterproof textured exterior wall latex paint:

[0051] a. Pre-dispersion: 4.2 parts of pH-responsive nano-SiO2 aerogel microspheres were pre-dispersed in a portion (4.2 parts) of water and dispersed at high speed at 1900 rpm for 17 minutes to prepare aerogel pre-dispersion slurry;

[0052] b. Slurry dispersion: First, add the remaining (8 parts) of water to the reactor, adjust the speed to 450 rpm, then add the antifreeze, dispersant, wetting agent, silicone defoamer and titanium dioxide slurry in sequence, and stir for 4 min; then increase the speed to 900 rpm, add barium sulfate and heavy calcium carbonate, and disperse for 7 min; then add cellulose, disperse for 7 min, add pH adjuster, and adjust the pH of the system to 8.7; then increase the speed to 1200 rpm, and disperse at high speed for 17 min until the detection fineness is ≤50μm;

[0053] c. Paint Mixing and Curing: After the slurry is dispersed, reduce the rotation speed to 600 rpm, and add the bactericide, waterproof emulsion, waterborne polyurethane dispersion, opaque polymer, aerogel pre-dispersion slurry prepared in step a, thickener diluent, and leveling agent in sequence. Finally, slowly add the dynamic silicone ester crosslinking agent. After all the materials are added, continue dispersing for 12 minutes until the system is uniformly mixed to obtain the waterproof textured exterior wall latex paint. After the paint is applied, cure it for 7 days at 25°C and 50%RH.

[0054] Example 3

[0055] A waterproof textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: 13.8 parts water, 13 parts antifreeze, 1.1 parts dispersant, 0.35 parts wetting agent, 0.3 parts mineral oil defoamer, 0.8 parts organosilicon defoamer, 24 parts titanium dioxide paste, 14 parts barium sulfate, 14 parts heavy calcium carbonate, 0.25 parts cellulose, 0.25 parts pH adjuster, 0.7 parts bactericide, 39 parts waterproof emulsion, 7 parts waterborne polyurethane dispersion, 0.9 parts opaque polymer, 1.3 parts thickener diluent, 0.04 parts leveling agent, 4.8 parts pH-responsive nano-SiO2 aerogel microspheres, and 2.3 parts dynamic silicone ester crosslinking agent.

[0056] The titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 35 parts water, 0.25 parts cellulose, 0.65 parts dispersant, 0.35 parts wetting agent, 0.25 parts mineral oil defoamer, 0.35 parts bactericide, 0.25 parts pH adjuster, 52 parts titanium dioxide with a particle size of 200-400nm, and 12 parts titanium dioxide with a particle size of 10-50nm.

[0057] Preparation steps:

[0058] (1) Preparation of titanium dioxide slurry: Add water to the reactor, add cellulose at 500 rpm and stir for 2 min; then add dispersant, wetting agent, mineral oil defoamer and pH adjuster and stir for 3 min; then adjust the speed to 1000 rpm, add titanium dioxide with a particle size of 200-400 nm and titanium dioxide with a particle size of 10-50 nm and stir until uniform; then adjust the speed to 1500 rpm and stir for 15 min, and check the fineness of the slurry ≤50 μm; finally add bactericide and stir evenly to obtain titanium dioxide slurry.

[0059] (2) Preparation of waterproof textured exterior wall latex paint:

[0060] a. Pre-dispersion: 4.8 parts of pH-responsive nano-SiO2 aerogel microspheres were pre-dispersed in a portion (4.8 parts) of water and dispersed at high speed at 2000 rpm for 19 minutes to prepare aerogel pre-dispersion slurry;

[0061] b. Slurry dispersion: First, add the remaining (9 parts) water to the reactor, adjust the speed to 500 rpm, then add the antifreeze, dispersant, wetting agent, mineral oil defoamer and organosilicon defoamer (the two defoamers are not in any particular order), and titanium dioxide slurry in sequence, and stir for 5 min; then increase the speed to 1000 rpm, add barium sulfate and heavy calcium carbonate, and disperse for 9 min; then add cellulose, disperse for 9 min, add pH adjuster, and adjust the pH of the system to 8.9; then increase the speed to 1400 rpm, and disperse at high speed for 19 min until the detection fineness is ≤50μm;

[0062] c. Paint Mixing and Curing: After the slurry is dispersed, reduce the rotation speed to 700 rpm, and add the bactericide, waterproof emulsion, waterborne polyurethane dispersion, opaque polymer, aerogel pre-dispersion slurry prepared in step a, thickening and diluting liquid, and leveling agent in sequence. Finally, slowly add the dynamic silicone ester crosslinking agent. After the addition is complete, continue dispersing for 14 minutes until the system is uniformly mixed to obtain the waterproof textured exterior wall latex paint. After the paint is applied, cure it for 7 days at 25°C and 50%RH.

[0063] Example 4

[0064] A waterproof textured exterior wall latex paint is mainly prepared from the following raw materials in the following weight proportions: 15.2 parts water, 14 parts antifreeze, 1.2 parts dispersant, 0.4 parts wetting agent, 0.7 parts silicone defoamer, 0.5 parts mineral oil defoamer, 25 parts titanium dioxide paste, 15 parts barium sulfate, 15 parts heavy calcium carbonate, 0.3 parts cellulose, 0.3 parts pH adjuster, 0.8 parts bactericide, 40 parts waterproof emulsion, 8 parts waterborne polyurethane dispersion, 1 part opaque polymer, 1.4 parts thickener diluent, 0.05 parts leveling agent, 5.2 parts pH-responsive nano-SiO2 aerogel microspheres, and 2.5 parts dynamic silicone ester crosslinking agent.

[0065] The titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 40 parts water, 0.3 parts cellulose, 0.7 parts dispersant, 0.4 parts wetting agent, 0.1 parts mineral oil defoamer, 0.2 parts organosilicon defoamer, 0.4 parts bactericide, 0.3 parts pH adjuster, 55 parts titanium dioxide with a particle size of 200-400nm, and 15 parts titanium dioxide with a particle size of 10-50nm.

[0066] Preparation steps:

[0067] (1) Preparation of titanium dioxide slurry: Add water to the reactor, add cellulose at 500 rpm and stir for 2 min; then add dispersant, wetting agent, mineral oil defoamer, organosilicon defoamer and pH adjuster and stir for 3 min; then adjust the speed to 1000 rpm, add titanium dioxide with a particle size of 200-400 nm and titanium dioxide with a particle size of 10-50 nm and stir until uniform; then adjust the speed to 1500 rpm and stir for 15 min, and check the fineness of the slurry ≤50 μm; finally add bactericide and stir evenly to obtain titanium dioxide slurry.

[0068] (2) Preparation of waterproof textured exterior wall latex paint:

[0069] a. Pre-dispersion: 5.2 parts of pH-responsive nano-SiO2 aerogel microspheres were pre-dispersed in a portion (5.2 parts) of water and dispersed at high speed at 2000 rpm for 20 minutes to prepare aerogel pre-dispersion slurry;

[0070] b. Slurry dispersion: First, add the remaining (10 parts) of water to the reactor, adjust the speed to 500 rpm, then add the antifreeze, dispersant, wetting agent, mineral oil defoamer and organosilicon defoamer (the two defoamers are not in any particular order), and titanium dioxide slurry in sequence, and stir for 5 min; then increase the speed to 1000 rpm, add barium sulfate and heavy calcium carbonate, and disperse for 10 min; then add cellulose, disperse for 10 min, add pH adjuster, and adjust the pH of the system to 9; then increase the speed to 1500 rpm, and disperse at high speed for 20 min until the detection fineness is ≤50μm;

[0071] c. Paint Mixing and Curing: After the slurry is dispersed, reduce the rotation speed to 1000 rpm, and add the bactericide, waterproof emulsion, waterborne polyurethane dispersion, opaque polymer, aerogel pre-dispersed slurry prepared in step a, thickener diluent, and leveling agent in sequence. Finally, slowly add the dynamic silicone ester crosslinking agent. After all the materials are added, continue dispersing for 15 minutes until the system is uniformly mixed to obtain the waterproof textured exterior wall latex paint. After the paint is applied, cure it for 7 days at 25°C and 50%RH.

[0072] Comparative Example

[0073] Commercially available ordinary textured exterior wall coatings (such as Nippon Paint's Elastic Textured Paint) do not contain pH-responsive nano-SiO2 aerogel microspheres and dynamic silicone ester crosslinking agents. Their main components are acrylic emulsion, heavy calcium carbonate, titanium dioxide, and conventional additives.

[0074] Table 1 Key performance test results of each embodiment and comparative example

[0075]

[0076] Examples 1-4 and the comparative examples above show that:

[0077] (1) All products in the embodiments of the present invention far exceed national standards, and their core performance is significantly better than that of the comparative examples. This proves that the introduction of pH-responsive nano-SiO2 aerogel microspheres and dynamic silicone ester crosslinking agents produces a synergistic gain effect.

[0078] (2) Texture effect and construction performance: The thixotropic index (3.2-3.5) of the present invention embodiment is much higher than that of the comparative example (1.8), indicating that the thixotropic skeleton constructed by pH-responsive nano-SiO2 aerogel microspheres effectively improves the anti-sagging and texture shaping ability of the coating during construction.

[0079] (3) Waterproof performance: The impermeability time (180 min) and contact angle (>118°) of the embodiment are greatly improved, which are significantly better than those of the comparative example, indicating that the dynamic cross-linking network formed by the present invention constructs a denser hydrophobic barrier.

[0080] (4) Weather resistance and durability: In the harsh high humidity environment test, the texture retention rate of the product of the present invention (≥92%) is much higher than that of the comparative example (65%), indicating that the time-space separation dual-function system has successfully solved the industry problem of easy softening and collapse of the texture in high humidity environment.

[0081] (5) The stain resistance, tensile strength and elongation at break of all products in the embodiments of the present invention are also improved with the increase of the amount of new components (i.e., pH-responsive nano-SiO2 aerogel microspheres and dynamic silicone ester crosslinking agent) (i.e., the performance is better), which reflects the synergistic effect of dynamic crosslinking network and pH-responsive nano-SiO2 aerogel reinforcement.

[0082] (6) The adhesion of all products in the embodiments of the present invention reaches the highest level 0.

[0083] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A waterproof, textured exterior wall latex paint, characterized in that: It is mainly prepared from the following raw materials in the following weight proportions: water 8.5-15.2 parts, antifreeze 10-14 parts, dispersant 0.8-1.2 parts, wetting agent 0.2-0.4 parts, defoamer 0.8-1.2 parts, titanium dioxide paste 19-25 parts, barium sulfate 10-15 parts, heavy calcium carbonate 10-15 parts, cellulose 0.1-0.3 parts, pH adjuster 0.1-0.3 parts, bactericide 0.4-0.8 parts, waterproof emulsion 37-40 parts, waterborne polyurethane dispersion 4-8 parts, opaque polymer 0.5-1 part, thickener diluent 1.0-1.4 parts, leveling agent 0.01-0.05 parts, pH-responsive nano-SiO2 aerogel microspheres 3.5-5.2 parts, dynamic silicone ester crosslinking agent 1.8-2.5 parts; The thickener dilution is prepared by mixing thickener and water at a mass ratio of 1:

1.

2. The waterproof textured exterior wall latex paint according to claim 1, characterized in that: The dynamic siloxane crosslinking agent is an aminosilane-terminated alkoxysilane crosslinking agent.

3. The waterproof textured exterior wall latex paint according to claim 1, characterized in that: The pH-responsive nano-SiO2 aerogel microspheres have a particle size of 800-1200 nm and a specific surface area ≥600 m². 2 / g, in which the volume of 2-8nm mesopores accounts for 64-66% and the volume of 50-200nm macropores accounts for 29-31%.

4. The waterproof textured exterior wall latex paint according to claim 1, characterized in that: The antifreeze is propylene glycol; the dispersant is a polycarboxylate dispersant; the wetting agent is a nonionic surfactant; the defoamer is one or more of organosilicon defoamers or mineral oil defoamers in any proportion; the pH adjuster is 2-amino-2-methyl-1-propanol; the bactericide is an isothiazolinone bactericide; the waterproof emulsion is an acrylate emulsion; the aqueous polyurethane dispersion is an aliphatic polyurethane dispersion; the opaque polymer is acrylic polymer microspheres; the thickener is a polyurethane thickener; the leveling agent is polyether-modified polydimethylsiloxane; and the cellulose is hydroxyethyl cellulose.

5. The waterproof textured exterior wall latex paint according to claim 1, characterized in that: The titanium dioxide paste is mainly prepared from the following raw materials in the following weight proportions: 20-40 parts water, 0.1-0.3 parts cellulose, 0.5-0.7 parts dispersant, 0.2-0.4 parts wetting agent, 0.1-0.3 parts defoamer, 0.2-0.4 parts bactericide, 0.2-0.3 parts pH adjuster, 45-55 parts titanium dioxide with a particle size of 200-400nm, and 5-15 parts titanium dioxide with a particle size of 10-50nm.

6. The waterproof textured exterior wall latex paint according to claim 5, characterized in that: The preparation method of the titanium dioxide slurry includes the following steps: water is added to a reaction vessel, and cellulose is added at a speed of 300-500 rpm, and stirred for 1-2 minutes; then defoamer, wetting agent, dispersant and pH adjuster are added, and stirred for 2-3 minutes; then the speed is adjusted to 800-1000 rpm, titanium dioxide with a particle size of 200-400 nm and titanium dioxide with a particle size of 10-50 nm are added, and stirred until uniform; then the speed is adjusted to 1300-1500 rpm, and stirred for 12-15 minutes until the fineness of the slurry is ≤50 μm; finally, bactericide is added, and stirred evenly to obtain titanium dioxide slurry.

7. The waterproof textured exterior wall latex paint according to claim 5, characterized in that: In titanium dioxide paste: the dispersant is a polycarboxylate dispersant; the wetting agent is a nonionic surfactant; the defoamer is one or more of organosilicon defoamers or mineral oil defoamers in any proportion; the pH adjuster is 2-amino-2-methyl-1-propanol; the bactericide is isothiazolinone bactericide; and the cellulose is hydroxyethyl cellulose.

8. The method for preparing waterproof textured exterior wall latex paint according to any one of claims 1-7, characterized in that: Includes the following steps: a. Pre-dispersion: 3.5-5.2 parts of pH-responsive nano-SiO2 aerogel microspheres are pre-dispersed in 3.5-5.2 parts of water, with a mass ratio of pH-responsive nano-SiO2 aerogel microspheres to water of 1:

1. The mixture is then dispersed at a shear rate of 1800-2000 rpm for 15-20 minutes to obtain aerogel pre-dispersion slurry. b. Slurry dispersion: First, add 5-10 parts of water to the reactor, adjust the rotation speed to 400-500 rpm, then add 10-14 parts of antifreeze, 0.8-1.2 parts of dispersant, 0.2-0.4 parts of wetting agent, 0.8-1.2 parts of defoamer, and 19-25 parts of titanium dioxide slurry in sequence, and stir for 3-5 minutes; then increase the rotation speed to 800-1000 rpm, add 10-15 parts of barium sulfate and 10-15 parts of heavy calcium carbonate, and disperse for 5-10 minutes; then add 0.1-0.3 parts of cellulose, and disperse for 5-10 minutes; then add 0.1-0.3 parts of pH adjuster to adjust the pH of the system to 8.6-9; then adjust the rotation speed to 1000-1500 rpm, and disperse at high speed for 15-20 minutes until the detection fineness is ≤50μm; c. Paint Mixing and Curing: After the slurry is dispersed, adjust the rotation speed to 500-1000 rpm, and add 0.4-0.8 parts of bactericide, 37-40 parts of waterproof emulsion, 4-8 parts of waterborne polyurethane dispersion, 0.5-1 parts of opaque polymer, the aerogel pre-dispersion slurry prepared in step a, 1.0-1.4 parts of thickener diluent and 0.01-0.05 parts of leveling agent in sequence. Finally, add 1.8-2.5 parts of dynamic silicone ester crosslinking agent. After the addition is complete, continue to disperse for 10-15 minutes until the system is mixed evenly to obtain waterproof textured exterior wall latex paint.

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