Water-based functional building exterior wall coating, preparation process and application thereof

Abstract

The application discloses a kind of water-based functional building outer wall coating and its preparation process and application, belong to coating technical field.The coating is composed of hydroxyl acrylic acid emulsion, fluorocarbon emulsion, iron-doped molybdenum disulfide / nano-cellulose composite, composite aerogel powder, modified mordenite, nano-SiO2 particle, intumescent flame retardant, auxiliary agent and water.Composite aerogel powder is the porous structure of SiO2 coated hollow Fe2O3 / TiO2;Intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol and melamine in a specific ratio.The preparation process of coating includes multiple steps, such as dispersion, stirring and pH adjustment, etc.The coating has excellent performance, such as low thermal conductivity, high antibacterial rate, long flame-retardant time and good artificial aging resistance, and can be applied to building outer wall.Compared with prior art, it solves the problem of functional stacking performance offset and poor compatibility of nanomaterials, and has wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and in particular relates to a water-based functional building exterior wall coating, its preparation process, and its application. Background Technology

[0002] Architectural exterior coatings play a crucial role in modern architecture, serving not only a decorative function but also protecting building structures from environmental erosion. Traditional exterior coatings are mostly solvent-based, posing a risk of volatile organic compound (VOC) emissions and potential harm to the environment and human health. With increasing environmental awareness and stricter regulations, water-based exterior coatings have gained widespread attention due to their environmental friendliness and pollution-free properties. However, existing water-based exterior coatings suffer from the following drawbacks: ① The simple stacking of self-cleaning, heat insulation, and antibacterial functions leads to performance attrition; ② Poor interfacial compatibility of nanomaterials causes long-term stability issues; ③ Static protection mechanisms cannot adapt to dynamic environmental stresses. Therefore, developing a high-performance, environmentally friendly water-based functional exterior coating is of significant practical importance. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a water-based functional building exterior wall coating, its preparation process, and its application.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the objectives of this invention is to provide a water-based functional building exterior wall coating, comprising the following raw materials in parts by weight: 30-50 parts of hydroxyl acrylic emulsion, 5-10 parts of fluorocarbon emulsion, 8-15 parts of iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF), 3-8 parts of composite aerogel powder (SiO2@Fe2O3 / TiO2), 10-25 parts of modified mordenite zeolite, 10-20 parts of nano-SiO2 particles, 5-10 parts of intumescent flame retardant, 2-8 parts of additives, and 15-30 parts of water;

[0006] in,

[0007] The composite aerogel powder has a porous structure of SiO2 coated with hollow Fe2O3 / TiO2;

[0008] The intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 2:1:1.

[0009] In this invention, building exterior wall coatings, due to long-term exposure to the natural environment, need to possess various functions such as mechanical properties, weather resistance, flame retardancy, and self-cleaning properties. These functions often rely on the synergistic effect of different components in the coating. The purpose of this invention is to ensure good compatibility between different components in the coating, guaranteeing the overall structural stability of the coating, thereby promoting the synergistic effect of multiple functions. To this end, this invention has rigorously screened and specifically combined each functional component. Specifically, the emulsion uses a combination of hydroxyl acrylic emulsion and fluorocarbon emulsion. The hydroxyl groups (-OH) in the hydroxyl acrylic emulsion undergo a cross-linking reaction with the active groups in the fluorocarbon emulsion, forming a three-dimensional network structure. Fluorocarbon segments are embedded into the acrylic backbone through chemical bonds, forming an organic-inorganic hybrid system. Due to their strong hydrophobicity, fluorocarbon segments tend to accumulate on the coating surface, forming low surface energy regions, while acrylic segments provide the main skeletal support, forming a gradient structure of "fluorocarbon shell - acrylic core". In the iron-doped molybdenum disulfide / nanocellulose composite, Fe... 3+ Doping into the layered structure of MoS2 enhances photocatalytic activity through d-orbital electron transitions. Hydroxyl groups of nanocellulose form hydrogen bonds with MoS2, improving the dispersibility of the composite and synergistically achieving antibacterial and heat-insulating functions. In the hollow Fe2O3 / TiO2 core-shell structure, Fe2O3 absorbs infrared light, while TiO2 decomposes pollutants through photocatalysis. The porous network of the SiO2 shell inhibits heat conduction, forming a synergistic "photocatalysis-heat insulation" system. The silane coupling agent KH570 undergoes a condensation reaction with the hydroxyl groups on the zeolite surface (Si-OH+HO-Si→Si-O-Si), introducing organic groups, improving compatibility with the polymer matrix, and enhancing the mechanical properties of the coating. Ammonium polyphosphate decomposes upon heating to generate phosphoric acid and ammonia. Phosphoric acid promotes the dehydration of pentaerythritol to form carbon, and melamine decomposes to generate nitrogen. The three work together to form an expanded carbon layer, isolating heat and oxygen. A specific combination of the three can improve the flame-retardant properties of the coating.

[0010] Furthermore, the preparation method of the iron-doped molybdenum disulfide / nanocellulose composite includes the following steps: mixing nanocellulose dispersion, molybdenum source, sulfur source and iron source in a mass ratio of 10:3:6:0.37, hydrothermally reacting at 200-220℃ for 18-24h, and obtaining the composite after washing and drying; wherein, the molybdenum source is ammonium molybdate, the sulfur source is thiourea, and the iron source is sodium iron ethylenediaminetetraacetate.

[0011] In this invention, under specific hydrothermal reaction conditions, molybdenum, sulfur, and iron sources react in a nanocellulose dispersion to generate Fe-MoS2 / CNF. The doping of iron ions not only enhances the antibacterial properties of molybdenum disulfide but also improves the stability of its layered structure, thereby resulting in better antibacterial and self-cleaning effects in coatings.

[0012] Furthermore, the preparation method of the composite aerogel powder includes the following steps: mixing hollow Fe2O3 powder with isopropyl titanate in ethanol, adding ammonia water to hydrolyze and generate a TiO2 coating layer, then reacting with tetraethyl orthosilicate to form a SiO2 shell, and drying with supercritical CO2 to obtain the powder.

[0013] In this invention, a composite aerogel with a porous structure is formed by sequentially coating TiO2 and SiO2 onto the surface of hollow Fe2O3 powder. This structure not only provides excellent thermal insulation performance but also enhances the self-cleaning function of the coating through the photocatalytic effect of TiO2. Simultaneously, the SiO2 shell further improves the stability and weather resistance of the aerogel.

[0014] Furthermore, the hollow Fe2O3 powder has a particle size of 200-500 nm and a wall thickness of 20-50 nm; and / or,

[0015] The TiO2 coating layer has a thickness of 10-30 nm; and / or,

[0016] The SiO2 outer shell has a thickness of 5-15 nm.

[0017] In this invention, precise control of these dimensions is crucial for achieving optimal thermal insulation and photocatalytic performance of the composite aerogel powder. The particle size and wall thickness of the hollow Fe2O3 powder affect its thermal conductivity, while the thickness of the TiO2 coating layer and the SiO2 shell affect the photocatalytic efficiency and structural stability.

[0018] Furthermore, the preparation method of the modified mordenite includes the following steps: modifying mordenite with silane coupling agent KH570 as a modifier to obtain modified mordenite; the amount of the modifier added is 1-3% of the mass of mordenite.

[0019] In this invention, mordenite is modified with silane coupling agent KH570, which improves the interfacial compatibility between mordenite and other components of the coating. This modification not only improves the mechanical properties of the coating but also enhances its weather resistance and aging resistance.

[0020] Furthermore, the nano-SiO2 particles have a particle size of 30-40 nm and a contact angle >150°.

[0021] In this invention, the particle size of nano-SiO2 particles affects their dispersibility and hardness in coatings, while a contact angle greater than 150° indicates that they have superhydrophobic properties, which helps to improve the self-cleaning properties and stain resistance of coatings.

[0022] Furthermore, the additives include film-forming aids, thickeners, dispersants, and wetting agents; the film-forming aid is dodecyl alcohol ester; the thickener is hydroxyethyl cellulose; the dispersant is sodium hexametaphosphate; and the wetting agent is CO-630.

[0023] This invention clarifies the specific types and functions of additives. The rational selection and proportioning of film-forming aids, thickeners, dispersants, and wetting agents help improve the application performance, dispersibility, and stability of coatings, thereby ensuring that the coatings fully demonstrate their various properties in practical applications.

[0024] The second objective of this invention is to provide a preparation process for a water-based functional building exterior wall coating, comprising the following steps:

[0025] (1) Add iron-doped molybdenum disulfide / nanocellulose composite, composite aerogel powder and modified mordenite to water and disperse at 600-800 rpm for 30 min;

[0026] (2) Add nano-SiO2 particles, intumescent flame retardant and some additives, and disperse at 1200 rpm for 40 min;

[0027] (3) Add hydroxy acrylic emulsion, fluorocarbon emulsion and remaining additives, stir at 400 rpm for 20 min to obtain water-based functional building exterior wall coating.

[0028] Further, in step (3), the pH is adjusted to 8.5-9.5 after stirring.

[0029] By employing staged dispersion and stirring, the uniform distribution of each component in the coating was ensured, preventing the agglomeration of nanomaterials and thus improving the overall performance of the coating. In particular, adjusting the pH value further optimized the stability and application properties of the coating.

[0030] The third objective of this invention is to provide an application of a water-based functional building exterior wall coating on building exterior walls.

[0031] The application of this coating in building exterior walls was clarified, emphasizing its practical value and market prospects. This coating possesses significant performance advantages and application potential in the field of building exterior walls.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] The coating provided by this invention has a thermal conductivity as low as 0.065 W / (m・K), an antibacterial rate of 99.8%, a long flame retardant time, no significant change in appearance after 1000 hours of artificial aging, high stain resistance and reflectivity retention, and good elongation at break.

[0034] This invention avoids the performance offsetting problem caused by simply stacking functions such as self-cleaning, heat insulation, and antibacterial properties, improves the long-term stability crisis caused by poor interfacial compatibility of nanomaterials, and breaks through the limitation that static protection mechanisms cannot adapt to dynamic environmental stress.

[0035] This invention pertains to water-based coatings, which, compared to traditional solvent-based coatings, reduce emissions of volatile organic compounds (VOCs), making them more environmentally friendly and beneficial to human health. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0041] This invention provides a water-based functional building exterior wall coating, comprising the following raw materials in parts by weight: 30-50 parts of hydroxyl acrylic emulsion (for example, 30, 40, or 50 parts can be selected), 5-10 parts of fluorocarbon emulsion (for example, 5, 7.5, or 10 parts can be selected), 8-15 parts of iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF) (for example, 8, 10, or 15 parts can be selected), 3-8 parts of composite aerogel powder (SiO2@Fe2O3 / TiO2) (for example, 3, 5, or 8 parts can be selected), and 10-25 parts of modified mordenite zeolite (for example, 3, 5, or 8 parts can be selected). For example, 10 parts, 15 parts, or 25 parts can be selected), 10-20 parts of nano-SiO2 particles (for example, 10 parts, 15 parts, or 20 parts can be selected), 5-10 parts of intumescent flame retardant (for example, 5 parts, 7.5 parts, or 10 parts can be selected), 2-8 parts of additives (for example, 2 parts, 5 parts, or 8 parts can be selected), and 15-30 parts of water (for example, 15 parts, 20 parts, or 30 parts can be selected); wherein, the composite aerogel powder is a porous structure of SiO2 coated with hollow Fe2O3 / TiO2; the intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 2:1:1.

[0042] In the following optional embodiments of the present invention, the preparation method of the iron-doped molybdenum disulfide / nanocellulose composite includes the following steps: mixing nanocellulose dispersion, molybdenum source, sulfur source and iron source in a mass ratio of 10:3:6:0.37, hydrothermally reacting at 200-220℃ for 18-24 h, and then washing and drying to obtain the composite; wherein the molybdenum source is ammonium molybdate, the sulfur source is thiourea, and the iron source is sodium iron ethylenediaminetetraacetate. Exemplarily, in the following preferred embodiments of the present invention, the preparation method of the iron-doped molybdenum disulfide / nanocellulose composite includes the following steps: mixing nanocellulose dispersion, ammonium molybdate, thiourea and sodium iron ethylenediaminetetraacetate in a mass ratio of 10:3:6:0.37, hydrothermally reacting at 220℃ for 20 h, washing, and drying to obtain the iron-doped molybdenum disulfide / nanocellulose composite.

[0043] In the following optional embodiments of the present invention, the preparation method of the composite aerogel powder includes the following steps: mixing hollow Fe2O3 powder with isopropyl titanate in ethanol, adding ammonia water for hydrolysis to generate a TiO2 coating layer, then reacting with tetraethyl orthosilicate to form a SiO2 shell, and drying with supercritical CO2 to obtain the final product. The hollow Fe2O3 powder has a particle size of 200-500 nm and a wall thickness of 20-50 nm; the TiO2 coating layer has a thickness of 10-30 nm; and the SiO2 shell has a thickness of 5-15 nm. For example, in the following preferred embodiments of the present invention, the preparation method of the composite aerogel powder includes the following steps: (1) 10g of hollow Fe2O3 powder is added to 200-300mL (e.g., 250mL) of ethanol, and stirred at room temperature using a magnetic stirrer at a speed of 300-500r / min (e.g., 300r / min) for 30min, so that the Fe2O3 powder is fully dispersed in the ethanol to form a uniform suspension; then 15-20mL (e.g., 18mL) of isopropyl titanate is slowly added to the above suspension, and stirring is continued for 1-2h (e.g., 1.5h) to ensure that the isopropyl titanate and Fe2O3 powder are fully mixed to obtain a mixed solution; (2) under continuous stirring (the speed is maintained at 300-500r / min, 300r / min), 10-15mL (e.g., 12mL) of a mixture with a mass fraction of 25-28% (e.g., 25%) of concentrated ammonia solution is slowly added dropwise to the mixed solution. During the dropwise addition, the solution will undergo a hydrolysis reaction to generate a TiO2 coating layer. After the dropwise addition is completed, the reaction is stirred for 2-3 hours (e.g., 2.5 hours). The reaction temperature is controlled at 30-40℃ (e.g., 35℃) to promote the full hydrolysis reaction. After the reaction is completed, a suspension containing TiO2-coated Fe2O3 powder is obtained. At this time, the thickness of the TiO2 coating layer is 10-30nm (e.g., 20nm). (3) 10-15mL (e.g., 12mL) of tetraethyl orthosilicate is slowly added to the above suspension. Stirring is maintained (speed 300-500r / min). The reaction is carried out at 30-40℃ (e.g., 35℃) for 4-6 hours (e.g., 5 hours) to allow the tetraethyl orthosilicate to hydrolyze and condense, forming a SiO2 shell outside the TiO2 coating layer with a thickness of 5-15nm.After the reaction is completed, the suspension is transferred to a centrifuge tube and centrifuged at a speed of 8000-10000 r / min (e.g. 8000 r / min) for 10-15 min (e.g. 10 min). The precipitate is collected and then washed with ethanol and deionized water alternately 3-5 times (e.g. 3 times) to remove unreacted raw materials and by-products. (4) The washed precipitate is transferred to the high pressure vessel of the supercritical drying equipment, the high pressure vessel is sealed, the temperature inside the high pressure vessel is raised to 40-50℃ (e.g. 45℃), and then CO2 gas is slowly introduced to gradually increase the pressure to 10-15MPa (e.g. 12MPa). The temperature and pressure conditions are maintained for 4-6h (e.g. 5h) so that CO2 reaches the supercritical state. In the supercritical state, CO2 has good dissolution and diffusion properties and can effectively remove the solvent in the precipitate. After that, the pressure and temperature are slowly reduced so that CO2 is discharged in gaseous form to obtain composite aerogel powder.

[0044] In the following optional embodiments of the present invention, the preparation method of the modified mordenite includes the following steps: modifying mordenite with silane coupling agent KH570 as a modifier to obtain modified mordenite; the amount of the modifier added is 1-3% (e.g., 3%) of the mass of mordenite. For example, in the following preferred embodiments of the present invention, the preparation method of the modified mordenite includes the following steps: (1) adding 1-3g (e.g., 1.5g) of silane coupling agent KH570 to 500-800mL (600mL) of anhydrous ethanol, and stirring at room temperature using a magnetic stirrer at a speed of 300-500r / min (e.g., 300r / min) for 15-30min (e.g., 20min) to fully dissolve the silane coupling agent KH570 in the anhydrous ethanol to form a uniform modifier solution; (2) placing the container containing mordenite and the modifier solution in a water bath, and stirring the reaction at 300-500r / min (e.g., 300r / min) at 40-60℃ (e.g., 50℃). 2-4h (e.g., 3h), during the reaction, the functional groups in the silane coupling agent KH570 molecule will react chemically with the hydroxyl groups on the surface of mordenite, thereby achieving the modification of mordenite; (3) after the reaction is completed, the mixed solution is transferred to a centrifuge tube and centrifuged at a speed of 8000-10000r / min (e.g., 8000r / min) for 10-15min (e.g., 15min), the precipitate is collected, and the precipitate is washed with anhydrous ethanol and deionized water alternately 3-5 times (e.g., 3 times) to remove unreacted silane coupling agent KH570 and other impurities. The washed precipitate is placed in a vacuum drying oven and dried at 60-80℃ (e.g., 60℃) for 6-12h (e.g., 8h) until the precipitate is completely dried, thus obtaining modified mordenite.

[0045] In the following optional embodiments of the present invention, the nano-SiO2 particles have a particle size of 30-40 nm and a contact angle >150°.

[0046] In the following optional embodiments of the present invention, the additives include film-forming aids, thickeners, dispersants, and wetting agents; the film-forming aid is dodecyl alcohol ester; the thickener is hydroxyethyl cellulose; the dispersant is sodium hexametaphosphate; and the wetting agent is CO-630.

[0047] This invention also provides a preparation process for a water-based functional building exterior wall coating, comprising the following steps:

[0048] (1) Add iron-doped molybdenum disulfide / nanocellulose composite, composite aerogel powder and modified mordenite to water and disperse at 600-800 rpm for 30 min;

[0049] (2) Add nano-SiO2 particles, intumescent flame retardant and some additives, and disperse at 1200 rpm for 40 min;

[0050] (3) Add hydroxy acrylic emulsion, fluorocarbon emulsion and remaining additives, stir at 400 rpm for 20 min to obtain water-based functional building exterior wall coating.

[0051] In the following optional embodiments of the present invention, the additives in step (2) are dispersants and wetting agents; the additives in step (3) are film additives and thickeners.

[0052] As an optional embodiment, this invention provides a novel water-based functional building exterior wall coating, comprising the following raw materials in parts by weight: 30-50 parts of hydroxyl acrylic emulsion (for example, 30, 40, or 50 parts can be selected), 5-10 parts of fluorocarbon emulsion (for example, 5, 7.5, or 10 parts can be selected), 8-15 parts of iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF) (for example, 8, 10, or 15 parts can be selected), 3-8 parts of composite aerogel powder (SiO2@Fe2O3 / TiO2) (for example, 3, 5, or 8 parts can be selected), and 10-25 parts of modified mordenite zeolite (for example, 10, 5, or 8 parts can be selected). The composite aerogel powder consists of 10-20 parts of nano-SiO2 particles (for example, 10, 15, or 20 parts can be selected), 5-10 parts of intumescent flame retardant (for example, 5, 7.5, or 10 parts can be selected), 2-8 parts of additives (for example, 2, 5, or 8 parts can be selected), 15-30 parts of water (for example, 15, 20, or 30 parts can be selected), and 0.5-1.5 parts of graphene oxide (GO) (for example, 1 part can be selected); wherein, the composite aerogel powder is a porous structure of SiO2 coated with hollow Fe2O3 / TiO2; the intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 2:1:1.

[0053] The oxygen-containing functional groups of GO (such as hydroxyl and carboxyl groups) can form hydrogen bonds with the hydroxyl groups of nanocellulose, enhancing the interfacial bonding of the composite. Simultaneously, the two-dimensional layered structure of GO stacks with the layered structure of Fe-MoS2, forming a "thermal barrier network" that synergistically reduces the thermal conductivity. Furthermore, GO's large specific surface area can adsorb polar groups on the aerogel surface, enhancing interfacial compatibility through π-π stacking, inhibiting aerogel powder agglomeration, and optimizing the uniformity of the porous structure.

[0054] In the following optional embodiments of the present invention, the pH is adjusted to 8.5-9.5 after stirring in step (3) (pH=9 can be selected as an example).

[0055] The water-based functional building exterior wall coating provided by this invention can be applied to building exterior walls.

[0056] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0057] Unless otherwise specified, the term "parts" in this invention refers to parts by weight.

[0058] All raw materials used in this invention were purchased from the market.

[0059] The technical solution of the present invention will be further illustrated by the following embodiments.

[0060] Example 1

[0061] A water-based functional building exterior wall coating comprises the following raw materials in parts by weight: 40 parts hydroxyl acrylic emulsion, 7.5 parts fluorocarbon emulsion, 10 parts iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF), 5 parts composite aerogel powder (SiO2@Fe2O3 / TiO2), 15 parts modified mordenite zeolite, 15 parts nano-SiO2 particles, 7.5 parts intumescent flame retardant (ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 2:1:1), 5 parts additives (2 parts film-forming aid dodecyl alcohol ester, 1 part thickener hydroxyethyl cellulose, 1 part dispersant sodium hexametaphosphate, 1 part wetting agent CO-630), and 20 parts water.

[0062] A method for preparing a water-based functional building exterior wall coating, comprising the following steps:

[0063] (1) Preparation of iron-doped molybdenum disulfide / nanocellulose composite:

[0064] 10g of nanocellulose dispersion, 3g of ammonium molybdate, 6g of thiourea and 0.37g of sodium iron ethylenediaminetetraacetate were mixed and hydrothermally reacted at 220℃ for 20h. After the reaction was completed, the product was washed three times with deionized water and vacuum dried at 60℃ for 12h to obtain iron-doped molybdenum disulfide / nanocellulose composite.

[0065] (2) Preparation of composite aerogel powder:

[0066] Add 10g of hollow Fe2O3 powder with a particle size of 200-500nm and a wall thickness of 20-50nm to 250mL of ethanol, stir at 300r / min for 30min, slowly add 18mL of isopropyl titanate, and continue stirring for 1.5h to obtain a mixed solution.

[0067] At 30℃, 12 mL of concentrated ammonia solution with a mass concentration of 25% was added dropwise to the mixture. After the addition was completed, the mixture was stirred for 2.5 h to generate a TiO2 coating layer with a thickness of 20 nm.

[0068] Add 12 mL of tetraethyl orthosilicate and react at 35 °C for 5 h to form a SiO2 shell with a thickness of 10 nm. After centrifugation at 8000 r / min for 10 min, wash three times alternately with ethanol and deionized water.

[0069] The precipitate was transferred to a supercritical drying device and dried with CO2 at 45℃ and 12MPa for 5h to obtain composite aerogel powder.

[0070] (3) Preparation of modified mordenite zeolite:

[0071] Add 1.5g of silane coupling agent KH570 (the amount of modifier added is 3% of the mass of mordenite) to 600mL of anhydrous ethanol and stir at 300r / min for 20min until completely dissolved.

[0072] Add 50g of mordenite zeolite and stir in a 50℃ water bath for 3h to allow KH570 to react with the hydroxyl groups on the surface of mordenite zeolite.

[0073] After the reaction, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol and deionized water, and dried under vacuum at 60℃ for 8 h to obtain modified mordenite zeolite.

[0074] (4) Preparation of coatings:

[0075] 10 parts of iron-doped molybdenum disulfide / nanocellulose composite, 5 parts of composite aerogel powder and 15 parts of modified mordenite were added to 20 parts of water and dispersed at 600 rpm for 30 min to form a uniform suspension.

[0076] Add 15 parts of nano-SiO2 particles (particle size 30-40nm, contact angle >150°), 7.5 parts of intumescent flame retardant and some additives (dispersant and wetting agent), and disperse at 1200rpm for 40min;

[0077] Add 40 parts of hydroxyl acrylic emulsion, 7.5 parts of fluorocarbon emulsion and the remaining additives (film-forming aid and thickener), stir at 400 rpm for 20 min, and finally adjust the pH of the system to 9 with ammonia water to obtain water-based functional building exterior wall coating.

[0078] Example 2

[0079] A water-based functional building exterior wall coating comprises the following raw materials in parts by weight: 30 parts hydroxyl acrylic emulsion, 5 parts fluorocarbon emulsion, 8 parts iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF), 3 parts composite aerogel powder (SiO2@Fe2O3 / TiO2), 10 parts modified mordenite zeolite, 20 parts nano-SiO2 particles, 10 parts intumescent flame retardant (ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 2:1:1), 8 parts additives (2 parts film-forming aid dodecyl alcohol ester, 2 parts thickener hydroxyethyl cellulose, 2 parts dispersant sodium hexametaphosphate, 2 parts wetting agent CO-630), and 15 parts water.

[0080] The preparation method is the same as in Example 1.

[0081] Example 3

[0082] A water-based functional building exterior wall coating comprises the following raw materials in parts by weight: 50 parts hydroxyl acrylic emulsion, 10 parts fluorocarbon emulsion, 15 parts iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF), 8 parts composite aerogel powder (SiO2@Fe2O3 / TiO2), 25 parts modified mordenite zeolite, 10 parts nano-SiO2 particles, 5 parts intumescent flame retardant (ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 2:1:1), 2 parts additives (1 part film-forming aid dodecyl alcohol ester, 0.5 parts thickener hydroxyethyl cellulose, 0.3 parts dispersant sodium hexametaphosphate, 0.2 parts wetting agent CO-630), and 30 parts water.

[0083] The preparation method is the same as in Example 1.

[0084] Comparative Example 1

[0085] Same as Example 3, except that the iron-doped molybdenum disulfide / nanocellulose composite is replaced by an equal mass of molybdenum disulfide / nanocellulose composite. The preparation method of the molybdenum disulfide / nanocellulose composite is as follows: 10g of nanocellulose dispersion, 3g of ammonium molybdate, and 6g of thiourea are mixed and hydrothermally reacted at 220°C for 20h. After the reaction is completed, the product is washed three times with deionized water and vacuum dried at 60°C for 12h to obtain the molybdenum disulfide / nanocellulose composite.

[0086] The preparation method is the same as in Example 1.

[0087] Comparative Example 2

[0088] Same as Example 3, except that the modified mordenite is replaced with mordenite.

[0089] The preparation method is the same as in Example 1.

[0090] Comparative Example 3

[0091] Same as Example 3, except that the mass ratio of ammonium polyphosphate, pentaerythritol and melamine is 1:1:1.

[0092] The preparation method is the same as in Example 1.

[0093] Comparative Example 4

[0094] The raw materials and dosages are the same as in Example 3;

[0095] A method for preparing a water-based functional building exterior wall coating, comprising the following steps:

[0096] (1) Preparation of iron-doped molybdenum disulfide / nanocellulose composite: same as in Example 1;

[0097] (2) Preparation of composite aerogel powder: Same as in Example 1;

[0098] (3) Preparation of modified mordenite: Same as in Example 1;

[0099] (4) Preparation of coatings:

[0100] 15 parts of iron-doped molybdenum disulfide / nanocellulose composite, 8 parts of composite aerogel powder, 25 parts of modified mordenite zeolite, 30 parts of water, 10 parts of nano-SiO2 particles, 5 parts of intumescent flame retardant, 50 parts of hydroxyl acrylic emulsion, 10 parts of fluorocarbon emulsion, and 2 parts of additives (1 part of film-forming aid dodecyl alcohol ester, 0.5 parts of thickener hydroxyethyl cellulose, 0.3 parts of dispersant sodium hexametaphosphate, and 0.2 parts of wetting agent CO-630) were mixed and stirred at 800 rpm for 20 min to obtain the coating.

[0101] Comparative Example 5

[0102] Same as Example 3, except that the composite aerogel powder is replaced with ordinary SiO2 aerogel by the same mass.

[0103] Performance testing:

[0104] The coatings prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests. The specific test methods were as follows:

[0105] 1. Thermal conductivity: The thermal conductivity of the coating was tested using a thermal conductivity tester in accordance with GB / T 25261-2018 standard. The thermal insulation exterior wall coating was applied into a 30×30×3cm mold with a coating thickness of 3mm. The coating was then tested after curing at room temperature for 7 days.

[0106] 2. Antibacterial rate: The antibacterial properties of the coating were evaluated by co-culturing two types of bacteria: Gram-negative Escherichia coli (E. coli, ATCC 25922) and Gram-positive Staphylococcus aureus (S. aureus, ATCC 25923) with the coating.

[0107] Experimental group: 1.0 × 10 7 CFU / mL -1 A mixed bacterial culture of Escherichia coli and Staphylococcus aureus was added to a petri dish, and a certain amount of culture medium was poured in and mixed evenly. Then, a sample with a diameter of 10 mm and a thickness of 5 mm, which was pressed using the solidified and sterilized coating obtained in Examples 1-3 and Comparative Examples 1-5, was placed into the culture medium. The culture medium was then placed in a constant temperature incubator at 37°C for 24-48 hours.

[0108] Control group: 1.0×10 7 CFU / mL -1Add the mixed bacterial culture of Escherichia coli and Staphylococcus aureus to the petri dish, then pour in a certain amount of culture medium and mix well. Then place the culture medium in a 37°C constant temperature incubator for 24-48 hours.

[0109] Determination of antibacterial rate: Count the number of bacterial colonies according to the national standard GB / T 4789.2, and then calculate the antibacterial efficiency of the sample according to the following formula: (AB) / B×100%, where A is the number of colonies corresponding to the control group sample and B is the number of colonies corresponding to the experimental group sample.

[0110] 3. Flame retardant time: Apply the thermal insulation exterior wall coating to one side of a 20×20cm plywood with a coating thickness of 5mm, cure for 7 days, place the coated side down above an alcohol lamp, 2.5cm away from the alcohol lamp, and record the time required for the plywood to carbonize to test the flame retardant ability of the thermal insulation exterior wall coating.

[0111] 4. Resistance to artificial aging: Tested according to the relevant standards of JGT 172-2005.

[0112] 5. Stain resistance (reflectivity retention rate %): Tested according to the relevant standard JGT 172-2005.

[0113] 6. Elongation at break: Tested according to JGT 172-2005 standard.

[0114] The results are shown in Table 1.

[0115] Table 1. Coating performance of Examples 1-3 and Comparative Examples 1-5

[0116]

[0117] As can be seen from Comparative Example 1 in Table 1, the lack of iron ion antibacterial activity leads to a decrease in antibacterial rate and an increase in thermal conductivity. As can be seen from Comparative Example 2, the unmodified mordenite results in poor interfacial compatibility, stress concentration in the coating, and a decrease in elongation at break. At the same time, poor interfacial compatibility also leads to a decrease in hydrophobicity, and the coating's stain resistance is also significantly affected. As can be seen from Comparative Example 3, the reduced proportion of ammonium polyphosphate results in insufficient acid source, a decrease in the density of the expanded carbon layer, and a shortened flame retardant time. As can be seen from Comparative Example 4, the lack of staged dispersion leads to the agglomeration of nanomaterials, poor coating uniformity, and a significant decrease in resistance to artificial aging and mechanical properties. As can be seen from Comparative Example 5, the use of ordinary SiO2 aerogel results in a decrease in thermal conductivity and aging resistance.

[0118] Example 4

[0119] A water-based functional building exterior wall coating comprises the following raw materials in parts by weight: 50 parts hydroxyl acrylic emulsion, 10 parts fluorocarbon emulsion, 15 parts iron-doped molybdenum disulfide / nanocellulose composite (Fe-MoS2 / CNF), 8 parts composite aerogel powder (SiO2@Fe2O3 / TiO2), 25 parts modified mordenite zeolite, 10 parts nano-SiO2 particles, 5 parts intumescent flame retardant (ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 2:1:1), 2 parts additives (1 part film-forming aid dodecyl alcohol ester, 0.5 parts thickener hydroxyethyl cellulose, 0.3 parts dispersant sodium hexametaphosphate, 0.2 parts wetting agent CO-630), 30 parts water, and 1 part graphene oxide (GO).

[0120] A method for preparing a water-based functional building exterior wall coating, comprising the following steps:

[0121] (1) Preparation of iron-doped molybdenum disulfide / nanocellulose composite: same as in Example 1;

[0122] (2) Preparation of composite aerogel powder: Same as in Example 1;

[0123] (3) Preparation of modified mordenite: Same as in Example 1;

[0124] (4) Preparation of coatings:

[0125] 15 parts of iron-doped molybdenum disulfide / nanocellulose composite, 8 parts of composite aerogel powder, 25 parts of modified mordenite zeolite and 1 part of graphene oxide were added to 30 parts of water and dispersed at 600 rpm for 30 min to form a uniform suspension.

[0126] Add 10 parts of nano-SiO2 particles (particle size 30-40nm, contact angle >150°), 5 parts of intumescent flame retardant and some additives (dispersant and wetting agent), and disperse at 1200rpm for 40min.

[0127] Add 50 parts of hydroxyl acrylic emulsion, 10 parts of fluorocarbon emulsion and the remaining additives (film-forming aid and thickener), stir at 400 rpm for 20 min, and finally adjust the pH of the system to 9 with ammonia water to obtain water-based functional building exterior wall coating.

[0128] The coating was prepared using the coating from Example 4, and its performance was tested. The results are shown in Table 2.

[0129] Table 2. Properties of the coatings prepared in Example 4

[0130]

[0131] As can be seen from Table 2, after adding 1 part of GO in Example 4, the thermal conductivity decreased to 0.065 W / (m・K), the antibacterial rate reached 99.8%, and the stain resistance and reflectivity retention rate increased to 91%. This is because the two-dimensional layered structure of GO and Fe-MoS2 stacked together form a "thermal conductive barrier network", and its oxygen-containing functional groups form hydrogen bonds with nanocellulose, which enhances the interfacial bonding force.

[0132] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A water-based functional building exterior wall coating, characterized in that, The raw materials include the following parts by weight: 30-50 parts of hydroxyl acrylic emulsion, 5-10 parts of fluorocarbon emulsion, 8-15 parts of iron-doped molybdenum disulfide / nanocellulose composite, 3-8 parts of composite aerogel powder, 10-25 parts of modified mordenite zeolite, 10-20 parts of nano-SiO2 particles, 5-10 parts of intumescent flame retardant, 2-8 parts of additives, 15-30 parts of water, and 0.5-1.5 parts of graphene oxide. in, The composite aerogel powder is a porous structure of SiO2 coated with hollow Fe2O3 / TiO2. The preparation method includes the following steps: mixing hollow Fe2O3 powder with isopropyl titanate in ethanol, adding ammonia water to hydrolyze and generate a TiO2 coating layer, then reacting with tetraethyl orthosilicate to form a SiO2 shell, and drying with supercritical CO2 to obtain the powder. The intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 2:1:1; The preparation method of the iron-doped molybdenum disulfide / nanocellulose composite includes the following steps: mixing nanocellulose dispersion, molybdenum source, sulfur source and iron source in a mass ratio of 10:3:6:0.37, hydrothermally reacting at 200-220℃ for 18-24h, and then washing and drying to obtain the composite; wherein, the molybdenum source is ammonium molybdate, the sulfur source is thiourea, and the iron source is sodium iron ethylenediaminetetraacetate. The preparation method of the modified mordenite includes the following steps: using silane coupling agent KH570 as a modifier to modify mordenite, thereby obtaining modified mordenite; the amount of the modifier added is 1-3% of the mass of mordenite.

2. The water-based functional building exterior wall coating according to claim 1, characterized in that, The hollow Fe2O3 powder has a particle size of 200-500 nm and a wall thickness of 20-50 nm; and / or, The TiO2 coating layer has a thickness of 10-30 nm; and / or, The SiO2 outer shell has a thickness of 5-15 nm.

3. The water-based functional building exterior wall coating according to claim 1, characterized in that, The nano-SiO2 particles have a particle size of 30-40 nm and a contact angle >150°.

4. The water-based functional building exterior wall coating according to claim 1, characterized in that, The additives include film-forming aids, thickeners, dispersants, and wetting agents.

5. A preparation process for a water-based functional building exterior wall coating as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Add iron-doped molybdenum disulfide / nanocellulose composite, composite aerogel powder, modified mordenite and graphene oxide to water and disperse at 600-800 rpm for 30 min. (2) Add nano-SiO2 particles, intumescent flame retardant and some additives, and disperse at 1200 rpm for 40 min; (3) Add hydroxy acrylic emulsion, fluorocarbon emulsion and remaining additives, stir at 400 rpm for 20 min to obtain water-based functional building exterior wall coating.

6. The preparation process of the water-based functional building exterior wall coating according to claim 5, characterized in that, After stirring in step (3), adjust the pH to 8.5-9.

5.

7. The application of a water-based functional building exterior wall coating as described in any one of claims 1-4 on building exterior walls.

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