Environment-friendly water-based building coating and preparation method thereof
By doping sodium alginate aerogel with titanium dioxide and modifying it with trimethylethoxysilane, the problem of poor compatibility between aerogel and water-based coating systems was solved, the thermal insulation performance and mechanical strength of the coating were improved, and stable dispersibility and workability were achieved.
Patent Information
- Application Number
- CN202511457616.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2026-01-13
AI Technical Summary
In existing water-based coatings, aerogels have poor compatibility with the water-based coating system, resulting in a decrease in thermal insulation performance. Furthermore, existing modification methods, by adding surfactants, can clog the pores of the aerogel, further weakening its thermal insulation performance.
Using titanium dioxide-doped sodium alginate aerogel as a filler, and modified with trimethylethoxysilane, combined with thickeners, defoamers and leveling agents, an environmentally friendly water-based architectural coating was prepared, ensuring the stable dispersibility of the aerogel in the water-based system and its compatibility with acrylic resin.
It improves the thermal insulation and mechanical strength of the coating, avoids interface defects, achieves stable dispersion of aerogel in the water-based system, and enhances the water resistance and application performance of the coating.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of coating technology, specifically relating to an environmentally friendly water-based architectural coating and its preparation method. Background Technology
[0002] Building energy consumption accounts for a significant proportion of global energy consumption, especially in maintaining comfortable internal temperatures. Therefore, implementing efficient thermal insulation measures for buildings is a key way to achieve winter warmth, summer cooling, and effective energy savings. To address this need, developing new green and low-carbon building materials with excellent thermal insulation properties has become an important research direction.
[0003] Waterborne architectural coatings, as a representative of environmentally friendly materials, significantly reduce the content of volatile organic compounds (VOCs) in products due to their use of water as the main solvent or dispersion medium. This reduces environmental pollution and improves the safety and convenience of production and application processes, making them one of the mainstream directions in modern coating development. Although waterborne systems have significant environmental advantages, their performance (such as water resistance and thermal insulation performance) often needs to be improved and enhanced by adding specific additives and optimizing the formulation structure.
[0004] In the prior art, aerogels are considered ideal thermal insulation fillers for coatings due to their ultra-low thermal conductivity. However, aerogels have poor compatibility with water-based coating systems. Existing modification schemes improve dispersibility by adding surfactants, but the introduction of surfactants will block the pores of the aerogel and weaken its thermal insulation performance. Summary of the Invention
[0005] In view of the above situation and to overcome the defects of the prior art, the purpose of this invention is to provide an environmentally friendly water-based architectural coating and its preparation method, so as to at least partially solve the problems mentioned in the background art.
[0006] The technical solution adopted in this invention is as follows: The first aspect of this invention provides an environmentally friendly water-based architectural coating, comprising the following components in parts by weight: 100 parts of water-based acrylic emulsion, 10-40 parts of filler, and 3-6 parts of additives, wherein the filler comprises trimethylethoxysilane-modified aerogel, and the aerogel is titanium dioxide-doped sodium alginate aerogel.
[0007] In some embodiments of the present invention, the titanium dioxide doping amount in the aerogel is 3wt%-8wt%.
[0008] In some embodiments of the present invention, the additives include thickeners, defoamers, and leveling agents, wherein the mass ratio of the thickener, defoamer, and leveling agent is 1:(0.5-1):(1-2).
[0009] A second aspect of this invention provides a method for preparing an environmentally friendly water-based architectural coating, comprising the following steps: Add the additives to the water-based acrylic emulsion and stir until the mixture is uniform. Then gradually add the filler and stir. Let it stand for 20-30 minutes to obtain an environmentally friendly water-based architectural coating.
[0010] In some embodiments of the present invention, the method for preparing the filler includes the following steps: Trimethylethoxysilane was added to an organic solvent to prepare a solution, and then the aerogel was added to the solution. The mixture was stirred at 20-30℃ for 15-30 minutes. After the reaction was completed, the product was removed, washed and dried, and then transferred to a planetary ball mill for ball milling to obtain the filler.
[0011] In some embodiments of the present invention, the mass ratio of trimethylethoxysilane to aerogel is (0.5-0.8):1.
[0012] In some embodiments of the present invention, the ball milling time is 25-30 min and the rotation speed is 200-300 rpm.
[0013] In some embodiments of the present invention, the method for preparing the aerogel includes the following steps: Add sodium alginate to deionized water and stir in a 50-60℃ water bath until the sodium alginate is completely dissolved to obtain a sodium alginate solution. Nano-titanium dioxide was added to sodium alginate solution and stirred for 0.5-1 h to form a uniform slurry. Boric acid was then added and the cross-linking reaction was carried out for 2-4 h to obtain a gel. The gel is first pre-cooled and shaped, then placed in a vacuum freeze dryer for freeze drying to obtain an aerogel.
[0014] In some embodiments of the present invention, the mass ratio of boric acid to sodium alginate is (1-3):50.
[0015] In some embodiments of the present invention, the pre-cooling molding temperature is -20°C and the time is 5-8 hours, and the freeze-drying temperature is -50°C and the time is 30-40 hours.
[0016] The beneficial effects achieved by this invention are as follows: This invention employs titanium dioxide-doped sodium alginate aerogel filler, which combines a three-dimensional porous thermal insulation structure with enhanced mechanical strength. The internal titanium dioxide component further enhances the thermal insulation performance by reflecting and scattering ultraviolet rays. Meanwhile, the trimethylethoxysilane-modified aerogel achieves a fine balance between hydrophobicity and hydrophilicity, ensuring excellent compatibility with the acrylic resin matrix and avoiding interfacial defects, while maintaining the stable dispersion of the filler in the aqueous system by appropriately retaining silanol groups. Detailed Implementation
[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.
[0019] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0020] In view of the shortcomings of the prior art mentioned in the background, the first aspect of the present invention proposes an environmentally friendly water-based architectural coating, comprising the following components in parts by weight: 100 parts of water-based acrylic emulsion, 10-40 parts of filler and 3-6 parts of additives. The water-based acrylic emulsion itself does not contain volatile organic compounds (VOCs) and can form a dense paint film at room temperature without the addition of film-forming aids, which is beneficial for construction on interior and exterior walls of buildings.
[0021] The filler includes a trimethylethoxysilane-modified aerogel, which is a titanium dioxide-doped sodium alginate aerogel. The three-dimensional porous structure of sodium alginate aerogel effectively blocks heat conduction, significantly improving the thermal insulation performance of the coating, and it also exhibits excellent biocompatibility and biodegradability. Doping sodium alginate aerogel with titanium dioxide enhances its mechanical strength, while the reflective and scattering properties of titanium dioxide further improve its thermal insulation effect. Partial hydrophobication of the aerogel using trimethylethoxysilane achieves a hydrophobic / hydrophilic balance, improving its compatibility with acrylic resin, while retaining an appropriate amount of silanol groups to maintain its dispersibility in aqueous systems.
[0022] In summary, this invention utilizes titanium dioxide-doped sodium alginate aerogel filler, which combines a three-dimensional porous thermal insulation structure with enhanced mechanical strength. The internal titanium dioxide component further enhances the thermal insulation performance by reflecting and scattering ultraviolet light. Meanwhile, the trimethylethoxysilane-modified aerogel achieves a fine balance between hydrophobicity and hydrophilicity, ensuring excellent compatibility with the acrylic resin matrix and avoiding interfacial defects, while maintaining stable dispersion of the filler in the aqueous system by appropriately retaining silanol groups.
[0023] In some embodiments, the titanium dioxide doping amount in the aerogel is 3wt%-8wt%. The titanium dioxide doping can embed into the pore walls of the sodium alginate aerogel to form a framework support. If the doping amount is too small, it cannot form an effective support, and if the doping amount is too large, it reduces the resilience of the aerogel. Therefore, the titanium dioxide doping amount needs to be set to 3wt%-8wt%.
[0024] In some embodiments, the additives include thickeners, defoamers, and leveling agents, with a mass ratio of thickener, defoamer, and leveling agent of 1:(0.5-1):(1-2). Thickeners increase the viscosity of the coating system, preventing sagging (coating flow down vertical surfaces), improving the thickness of a single coat, and reducing pigment sedimentation and stratification. Defoamers eliminate air bubbles generated during production or application, preventing defects such as pinholes and crater-like defects after coating drying. Leveling agents promote the formation of a smooth and uniform paint film during drying, eliminating defects such as brush marks and orange peel.
[0025] A second aspect of this invention provides a method for preparing an environmentally friendly water-based architectural coating, comprising the following steps: Add the additives to the water-based acrylic emulsion and stir until homogeneous. Then, gradually add the filler, stir, and let stand for 20-30 minutes to obtain an environmentally friendly water-based architectural coating. Allowing the filler to stand after thorough stirring ensures its complete dispersion in the water-based acrylic emulsion, improving the uniformity of filler dispersion.
[0026] In some embodiments, the method for preparing the filler includes the following steps: Trimethylethoxysilane was added to an organic solvent to prepare a solution, and then the aerogel was added to the solution. The mixture was stirred at 20-30℃ for 15-30 minutes. After the reaction was completed, the product was removed, washed and dried, and then transferred to a planetary ball mill for ball milling to obtain the filler.
[0027] Because sodium alginate aerogel is hydrophilic, direct addition to water-based coatings would cause water to fill the aerogel pores, reducing its thermal insulation performance. Trimethylethoxysilane is used for partial hydrophobication while retaining sufficient silanol groups to maintain hydrogen bonding with the acrylic resin. Furthermore, ball milling allows for control of the filler particle size within a suitable range, improving its dispersibility.
[0028] In some embodiments, the mass ratio of trimethylethoxysilane to aerogel is (0.5-0.8):1. By setting the mass ratio of trimethylethoxysilane to aerogel within a suitable range, the hydrophobic / hydrophilic balance of the aerogel can be balanced, the compatibility of the aerogel with acrylic resin can be improved, and an appropriate amount of silanol groups can be retained to maintain its dispersibility in aqueous systems.
[0029] In some embodiments, the ball milling time is 25-30 minutes and the rotation speed is 200-300 rpm. By controlling the ball milling time and rotation speed within a suitable range, the integrity of the aerogel microstructure can be maintained, while promoting the dispersibility of the filler in the coating.
[0030] In some embodiments, the preparation method of aerogel includes the following steps: adding sodium alginate to deionized water and stirring in a water bath at 50-60°C until the sodium alginate is completely dissolved to obtain a sodium alginate solution; adding nano-titanium dioxide to the sodium alginate solution and stirring for 0.5-1 h to form a uniform slurry; then adding boric acid and performing a crosslinking reaction for 2-4 h to obtain a gel; pre-cooling and molding the gel before placing it in a vacuum freeze dryer for freeze drying to obtain an aerogel.
[0031] Boric acid can undergo esterification with the hydroxyl groups on the sodium alginate molecular chain, promoting the chemical cross-linking of sodium alginate and facilitating gel formation. Furthermore, the borate ester bond between boric acid and sodium alginate can cross-link linear sodium alginate molecules into a three-dimensional network, significantly improving the mechanical strength of the aerogel.
[0032] In some embodiments, the mass ratio of boric acid to sodium alginate is (1-3):50. If there is too little boric acid, the cross-linking points between boric acid and sodium alginate are insufficient, resulting in loose connections between sodium alginate molecular chains and poor structural stability of the aerogel. If there is too much boric acid, the sodium alginate molecular chains become rigid, leading to poor flexibility of the aerogel. Therefore, the mass ratio of boric acid to sodium alginate needs to be set to (1-3):50.
[0033] In some embodiments, the pre-cooling molding temperature is -20°C for 5-8 hours, and the freeze-drying temperature is -50°C for 30-40 hours. Pre-cooling molding can fix the position of nano-titanium dioxide and prevent component segregation, while freeze-drying removes the ice template through sublimation, thereby obtaining an aerogel with a porous structure.
[0034] The present invention will be further described below by way of specific embodiments.
[0035] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods already existing in the art; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.
[0036] Example 1: Sodium alginate was added to deionized water and stirred in a 50°C water bath until the sodium alginate was completely dissolved to obtain a sodium alginate solution. Nano-titanium dioxide was added to sodium alginate solution with a titanium dioxide doping amount of 3wt%, and stirred for 0.5h to form a uniform slurry. Then boric acid was added with a mass ratio of boric acid to sodium alginate of 1:50, and the cross-linking reaction was carried out for 2h to obtain a gel. The gel was pre-cooled at -20℃ for 5 hours and then freeze-dried at -50℃ for 30 hours in a vacuum freeze dryer to obtain an aerogel.
[0037] Trimethylethoxysilane was added to an organic solvent to prepare a solution, and then aerogel was added to the solution. The mass ratio of trimethylethoxysilane to aerogel was 0.5:1. The mixture was stirred at 20°C for 15 min. After the reaction was completed, the product was taken out, washed and dried, and then transferred to a planetary ball mill for ball milling for 25 min at a speed of 200 rpm to obtain the filler.
[0038] Add 3 parts by weight of the additive to 100 parts of water-based acrylic emulsion and stir until evenly mixed. Then gradually add 10 parts of filler, stir, and let stand for 20 minutes to obtain an environmentally friendly water-based architectural coating.
[0039] Example 2: Add sodium alginate to deionized water and stir in a 60°C water bath until the sodium alginate is completely dissolved to obtain a sodium alginate solution. Nano-titanium dioxide was added to sodium alginate solution with a doping amount of 8wt%, and stirred for 1 hour to form a uniform slurry. Then boric acid was added with a mass ratio of boric acid to sodium alginate of 3:50, and the cross-linking reaction was carried out for 4 hours to obtain a gel. The gel was pre-cooled at -20℃ for 8 hours and then freeze-dried at -50℃ for 40 hours in a vacuum freeze dryer to obtain an aerogel.
[0040] Trimethylethoxysilane was added to an organic solvent to prepare a solution, and then aerogel was added to the solution. The mass ratio of trimethylethoxysilane to aerogel was 0.8:1. The mixture was stirred at 30°C for 30 min. After the reaction was completed, the product was taken out, washed and dried, and then transferred to a planetary ball mill for ball milling for 30 min at a speed of 300 rpm to obtain the filler.
[0041] According to the weight proportions, add 6 parts of the additive to 100 parts of water-based acrylic emulsion and stir until evenly mixed. Then, gradually add 40 parts of filler and stir. Let stand for 30 minutes to obtain an environmentally friendly water-based architectural coating.
[0042] Example 3: Consistent with Example 1, except that the titanium dioxide doping amount in the aerogel is 4 wt%.
[0043] Example 4: Consistent with Example 1, except that the titanium dioxide doping amount in the aerogel is 5 wt%.
[0044] Example 5: Consistent with Example 1, except that the titanium dioxide doping amount in the aerogel is 6 wt%.
[0045] Example 6: Consistent with Example 1, except that the titanium dioxide doping amount in the aerogel is 7 wt%.
[0046] Comparative Example 1: Consistent with Example 1, except that trimethylethoxysilane was not used to modify the aerogel.
[0047] Comparative Example 2: Consistent with Example 1, except that titanium dioxide is not used to dope the sodium alginate aerogel.
[0048] Tests were conducted on Examples 1-6 and Comparative Examples 1 and 2. The specific test contents are as follows: Thermal insulation performance test: The thermal insulation temperature difference of the thermal insulation coating was tested according to the procedures in GB / T 25261-2018 "Reflective Thermal Insulation Coatings for Buildings". The coating was applied to an aluminum plate with a thickness of 0.5 mm, and the coated aluminum plate was cured at room temperature for one week after application. Both the blackboard and the coated aluminum plate were uniformly illuminated by an artificial light source. After the temperature of the coated plate stabilized, the surface temperature of the coated plate was recorded, and the thermal insulation temperature difference between the blackboard and the coated aluminum plate was calculated. The test results are shown in Table 1.
[0049] Water resistance test: According to GB / T1733-1993 standard, 150x70x60mm asbestos-free fiber cement pressure boards were cleaned and coated twice using 120μm and 80μm wire bar applicators, with an interval of 6 hours. The boards were cured at room temperature for 7 days. The edges and back of the test boards were sealed with a 1:1 mixture of paraffin and rosin, and then placed in an aqueous solution, immersing 2 / 3 of the board in the solution. The boards were then sealed and covered for 96 hours. After immersion, the coating surface was observed for discoloration, blistering, peeling, or other phenomena. At least two test boards showed consistent coating phenomena that met the standard. The test results are shown in Table 1.
[0050] Impact resistance test: According to GB / T1732-2020 standard, a 1mm thick coating was applied to a 150x70x0.28mm tinplate test plate and cured for 7 days. Using an impact tester, the test plate was placed flat on the base using a forward impact method, and the hammer head was allowed to fall freely by adjusting the height of the impact tester and pressing the control button. The test plate was then removed and the coating was observed for cracks, wrinkles, and peeling. The test results are shown in Table 1.
[0051] Table 1
[0052] Referring to the test results in Table 1, the thermal insulation temperature difference of Comparative Example 1 decreased, possibly because modifying the aerogel with trimethylethoxysilane promotes filler dispersion in the coating, thereby improving the coating's thermal insulation effect. The thermal insulation temperature difference of Comparative Example 2 decreased significantly, indicating that doping sodium alginate aerogel with titanium dioxide can significantly improve the coating's thermal insulation performance. The water resistance of Comparative Example 1 decreased, indicating that hydrophobic modification of the aerogel with trimethylethoxysilane can improve the coating's water resistance. The impact resistance of Comparative Example 2 decreased, indicating that doping sodium alginate aerogel with titanium dioxide can improve the aerogel's mechanical properties, thus improving the coating's impact resistance.
[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0054] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.
Claims
1. An environmentally friendly water-based architectural coating, characterized in that, The product comprises the following components in parts by weight: 100 parts of aqueous acrylic emulsion, 10-40 parts of filler, and 3-6 parts of additives, wherein the filler comprises trimethylethoxysilane modified aerogel, and the aerogel is titanium dioxide-doped sodium alginate aerogel.
2. The environmentally friendly water-based architectural coating according to claim 1, characterized in that, The aerogel contains 3wt%-8wt% titanium dioxide doping.
3. The environmentally friendly water-based architectural coating according to claim 1, characterized in that, The additives include thickeners, defoamers, and leveling agents, and the mass ratio of the thickener, defoamer, and leveling agent is 1:(0.5-1):(1-2).
4. A method for preparing an environmentally friendly water-based architectural coating according to any one of claims 1-3, characterized in that, Includes the following steps: Add the additives to the water-based acrylic emulsion and stir until the mixture is uniform. Then gradually add the filler and stir. Let it stand for 20-30 minutes to obtain an environmentally friendly water-based architectural coating.
5. The preparation method according to claim 4, characterized in that, The method for preparing the filler includes the following steps: Trimethylethoxysilane was added to an organic solvent to prepare a solution, and then the aerogel was added to the solution. The mixture was stirred at 20-30℃ for 15-30 minutes. After the reaction was completed, the product was removed, washed and dried, and then transferred to a planetary ball mill for ball milling to obtain the filler.
6. The preparation method according to claim 5, characterized in that, The mass ratio of trimethylethoxysilane to aerogel is (0.5-0.8):
1.
7. The preparation method according to claim 5, characterized in that, The ball milling time is 25-30 minutes, and the rotation speed is 200-300 rpm.
8. The preparation method according to claim 5, characterized in that, The method for preparing the aerogel includes the following steps: Add sodium alginate to deionized water and stir in a 50-60℃ water bath until the sodium alginate is completely dissolved to obtain a sodium alginate solution. Nano-titanium dioxide was added to sodium alginate solution and stirred for 0.5-1 h to form a uniform slurry. Boric acid was then added and the cross-linking reaction was carried out for 2-4 h to obtain a gel. The gel is first pre-cooled and shaped, then placed in a vacuum freeze dryer for freeze drying to obtain an aerogel.
9. The preparation method according to claim 8, characterized in that, The mass ratio of boric acid to sodium alginate is (1-3):
50.
10. The preparation method according to claim 8, characterized in that, The pre-cooling molding temperature is -20℃ and the time is 5-8 hours, and the freeze-drying temperature is -50℃ and the time is 30-40 hours.