Self-cleaning coating as well as preparation method and application thereof

Abstract

The invention relates to a self-cleaning coating as well as a preparation method and application thereof, and relates to the technical field of coatings, and a self-cleaning functional component of the self-cleaning coating comprises modified titanium dioxide; the modified titanium dioxide is obtained by reacting titanium dioxide with an organic phosphonic acid compound as shown in a formula I. Under an existing self-cleaning coating formula system, titanium dioxide and an acridinyl-containing organic phosphonic acid compound are reacted according to a proper proportion, so that part of titanium dioxide is converted into an organic phosphonic acid titanium compound under the actions of acid-base neutralization, coordination and the like; modified titanium dioxide is endowed with double self-cleaning action mechanisms of a photocatalyst TiO2 and an air catalyst titanium phosphate, so that the self-cleaning effect of the coating is remarkably improved; meanwhile, the modified titanium dioxide can effectively enhance the bonding strength between the coating and the base material and improve the weather resistance of the coating, so that the self-cleaning use requirements of the surfaces of various base materials such as stones, aluminum plates and glass can be met.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a self-cleaning coating, its preparation method, and its application. Background Technology

[0002] With increasingly stringent performance requirements for building materials in modern society, self-cleaning coatings, as an innovative and practical functional coating, are gradually demonstrating enormous application potential in numerous fields such as construction, transportation, and home appliances. These coatings possess the ability to automatically remove surface contaminants, significantly reducing the frequency and cost of manual cleaning while ensuring that buildings maintain a consistently beautiful and clean appearance. This advantage perfectly aligns with the current development trend of green, environmentally friendly, and energy-saving building materials.

[0003] Currently, based on different self-cleaning principles, self-cleaning coatings can be mainly divided into two categories: superhydrophobic and superhydrophilic. Among superhydrophilic self-cleaning coatings, those with titanium dioxide as the main component dominate. However, existing titanium dioxide-based self-cleaning coatings still have shortcomings in performance, such as insufficient self-cleaning effect, poor weather resistance, and easy coating peeling, making it difficult to meet the self-cleaning requirements of exterior wall decoration materials such as stone, aluminum panels, and glass. Summary of the Invention

[0004] To address the above problems, this invention provides a self-cleaning coating, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a self-cleaning coating, wherein the self-cleaning functional component of the self-cleaning coating includes modified titanium dioxide; The modified titanium dioxide is obtained by reacting titanium dioxide with an organophosphonic acid compound represented by Formula I; Equation I: ; R1 and R2 are each independently hydrogen or C1~C3 alkyl; The weight ratio of the titanium dioxide to the organophosphonic acid compound is 100:(33~47).

[0006] Furthermore, the organophosphonic acid compound includes compound 1, the chemical structural formula of which is shown below: .

[0007] Furthermore, the weight ratio of the titanium dioxide to the organophosphonic acid compound is 100:41.

[0008] Furthermore, the preparation of the modified titanium dioxide includes the following process: Titanium dioxide was dispersed in water and ammonia was added to adjust the pH of the system to 8-8.5. Then, the organophosphonic acid compound was added and ultrasonically heated and stirred for 1-2 hours at an ultrasonic power of 150-200W and a temperature of 70-80℃. After the reaction was completed, the mixture was filtered, washed, dried and ground to obtain the modified titanium dioxide.

[0009] Furthermore, by weight, the self-cleaning coating comprises the following components: The composition consists of 90-100 parts of matrix emulsion, 5-10 parts of the modified titanium dioxide, 30-40 parts of filler, 4-7 parts of additives, and 15-20 parts of water.

[0010] Furthermore, by weight, the self-cleaning coating comprises the following components: The composition consists of 95 parts of matrix emulsion, 8.5 parts of the modified titanium dioxide, 35 parts of filler, 5 parts of additives, and 17 parts of water.

[0011] Furthermore, the matrix emulsion includes at least one of acrylic emulsion and styrene-acrylic emulsion; And / or, the filler comprises at least one of calcium carbonate and kaolin; And / or, the additives include at least one of dispersants, defoamers, leveling agents, and thickeners.

[0012] Secondly, based on the same inventive concept, the present invention provides a method for preparing the self-cleaning coating described in the first aspect above, the method comprising the following steps: Modified titanium dioxide was obtained; The modified titanium dioxide and the remaining components of the self-cleaning coating are mixed to obtain the self-cleaning coating.

[0013] Thirdly, based on the same inventive concept, the present invention provides the application of the self-cleaning coating as described in any one of the first aspects, or the self-cleaning coating prepared by the method of preparing the self-cleaning coating described in the second aspect, in the preparation of self-cleaning articles.

[0014] Furthermore, the self-cleaning product includes at least one of self-cleaning glass, self-cleaning steel, and self-cleaning stone.

[0015] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art: This invention provides a self-cleaning coating, its preparation method, and its application. In existing self-cleaning coating formulations, this invention primarily involves reacting a suitable proportion of titanium dioxide with an organophosphonic acid compound containing an acridine group. This allows some of the titanium dioxide to be converted into an organophosphonic titanium complex through processes such as acid-base neutralization and coordination. This modified titanium dioxide possesses a dual self-cleaning mechanism, combining the properties of photocatalytic TiO2 and air-catalyzed titanium phosphate, significantly improving the coating's self-cleaning effect. Simultaneously, the modified titanium dioxide effectively enhances the bonding strength between the coating and the substrate, improving the coating's weather resistance, thus meeting the self-cleaning requirements of various substrates such as stone, aluminum, and glass. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0017] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Furthermore, unless otherwise specified or detailed, the steps and parameters involved in this invention can be performed according to existing preparation processes or directly using existing equipment; these will not be elaborated upon further in this document.

[0018] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0019] The main raw material information involved in the following embodiments and comparative examples is as follows: Titanium dioxide: Commercially available, anatase titanium dioxide powder, nano-sized.

[0020] Compound 1: Prepared in-house according to a publicly disclosed preparation process, the preparation method of which includes: ; 9,10-dihydro-9,9-dimethylacridine (DmA) and bromoacetyl bromide were dissolved in toluene at a molar ratio of 1:2 and reacted under an inert atmosphere at 80°C with stirring for 12 h. After the reaction, the crude product was purified by silica gel column chromatography in petroleum ether / dichloromethane (volume ratio 5:2) to obtain a pale yellow solid (2ABrDmA). The obtained pale yellow solid was dissolved in a borane-tetrahydrofuran complex (BH3·THF, excess), and then boron trifluoride diethyl ether complex (BF3·OEt2) was slowly added at room temperature and under an inert atmosphere and reacted for 24 h. After the reaction, the crude product was purified by silica gel column chromatography in petroleum ether / dichloromethane (volume ratio 5:2) to obtain a white solid (2BrDmA). The white solid was dissolved in excess triethyl phosphite and reacted at 160°C for 24 h under an inert atmosphere. After the reaction was completed, the mixture was poured into petroleum ether at -70°C and stirred until no solid precipitate was formed, resulting in a white precipitate (2PDmA). The white precipitate was dissolved in 1,4-dioxane at room temperature, and excess trimethylbromosilane was slowly added and stirred for 24 hours under an argon atmosphere. The resulting mixed solution was then removed by a rotary evaporator and added to methanol and stirred for 3 hours. Deionized water was then added dropwise to the system until the solution gradually became opaque. The solution was filtered and recrystallized to obtain the target product (2PADmA).

[0021] Acrylic emulsion: Commercially available, Arkema® ENCOR 2167 acrylic emulsion.

[0022] Calcium carbonate: Commercially available, 325 mesh light calcium carbonate.

[0023] Kaolin: Commercially available, 600-mesh washed kaolin.

[0024] Dispersant: Commercially available, BYK-163.

[0025] Defoamer: Commercially available, Dow Corning DC65 defoamer.

[0026] Leveling agent: Commercially available, BYK-333.

[0027] Thickener: Commercially available, sodium polyacrylate.

[0028] Example 1 This example provides a self-cleaning coating, which, by weight, comprises the following components: The composition consists of 95 parts matrix emulsion, 8.5 parts modified titanium dioxide, 35 parts filler, 5 parts additives, and 17 parts water. The matrix emulsion is an acrylic emulsion; The modified titanium dioxide is obtained by reacting titanium dioxide and an organophosphonic acid compound (compound 1) in a weight ratio of 100:41: titanium dioxide is dispersed in 10 times its weight of water and ammonia is added to adjust the pH of the system to 8.3. Then, the organophosphonic acid compound (compound 1) is added and ultrasonically heated and stirred at 180W ultrasonic power and 75℃ for 1.5h. After the reaction is completed, the mixture is filtered, washed, dried, and the resulting solid is ground at 100rpm for 30min to obtain the modified titanium dioxide. The filler is composed of calcium carbonate and kaolin in a weight ratio of 3:1; The additives consist of a dispersant, a defoamer, a leveling agent, and a thickener in a weight ratio of 1:1.5:1:1.5.

[0029] The preparation method of the above self-cleaning coating includes the following steps: Modified titanium dioxide was obtained; The acrylic emulsion, water, dispersant and defoamer are stirred and mixed. Then, a pre-mixed mixture of modified titanium dioxide, calcium carbonate and kaolin is added and stirred and mixed again. Finally, the remaining components are added and stirred and mixed again to obtain the self-cleaning coating.

[0030] Example 2 This example provides a self-cleaning coating and its preparation method, which differs from Example 1 only in that: (1) By weight, the self-cleaning coating comprises the following components: 90 parts of base emulsion, 5 parts of modified titanium dioxide, 30 parts of filler, 4 parts of additives and 15 parts of water; (2) The weight ratio of the titanium dioxide and the organophosphonic acid compound is 100:33.

[0031] Example 3 This example provides a self-cleaning coating and its preparation method, which differs from Example 1 only in that: (1) By weight, the self-cleaning coating comprises the following components: 100 parts of base emulsion, 10 parts of modified titanium dioxide, 40 parts of filler, 7 parts of additives and 20 parts of water; (2) The weight ratio of the titanium dioxide and the organophosphonic acid compound is 100:47.

[0032] Comparative Example 1 This example provides a self-cleaning coating and its preparation method, which differs from Example 1 only in that: (1) The modified titanium dioxide was adjusted to the titanium dioxide raw material in Example 1 (i.e., the titanium dioxide was not modified).

[0033] Comparative Example 2 This example provides a self-cleaning coating and its preparation method, which differs from Example 1 only in that: (1) The weight ratio of the titanium dioxide and the organophosphonic acid compound is 1:1 (i.e., the amount of organophosphonic acid compound added is too much).

[0034] Test case This example demonstrates the performance testing of the self-cleaning coatings obtained in the above embodiments and comparative examples.

[0035] The testing method is as follows: 1) Self-cleaning performance: Refer to the test method in GB / T 31815-2015 Self-cleaning coatings for building exterior surfaces, conduct a 90-day outdoor rain stain test to test the self-cleaning performance of the coatings made for each test object; among them, the lower the stain resistance, the less likely it is to get stained, and the better the self-cleaning performance.

[0036] 2) Weather resistance stability test of coating: The self-cleaning coating sample was applied to the substrate surface under the same conditions, and then subjected to alternating cycles of ultraviolet irradiation for 8 hours (60℃) and damp heat cycling for 4 hours (40℃, relative humidity 90%). After 600 hours, the coating was observed to see if there were any cracks, peeling or discoloration.

[0037] The test results are shown in Table 1.

[0038] Table 1

[0039] As shown in Table 1, compared with Comparative Examples 1-2, the self-cleaning coating provided by the present invention has better self-cleaning effect and weather resistance stability. This indicates that the present invention significantly improves the self-cleaning performance and weather resistance of the obtained self-cleaning coating by introducing modified titanium dioxide obtained by reacting an appropriate proportion of titanium dioxide and an organophosphonic acid compound containing an acridine group, and can meet the self-cleaning requirements of various substrates such as stone, aluminum plate, and glass.

[0040] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0041] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A self-cleaning coating, characterized in that, The self-cleaning function component of the self-cleaning coating comprises modified titanium dioxide; The modified titanium dioxide is obtained by reacting titanium dioxide and an organic phosphonic acid compound shown in formula I; the formula I: ; wherein R1 and R2 are each independently hydrogen or C1-C3 alkyl; The weight ratio of the titanium dioxide to the organic phosphonic acid compound is 100: (33-47).

2. The self-cleaning coating according to claim 1, characterized in that, The organic phosphonic acid compound comprises compound 1, and the chemical structural formula of the compound 1 is shown as follows: 。 3. The self-cleaning coating according to claim 1, wherein The weight ratio of the titanium dioxide to the organic phosphonic acid compound is 100:

41.

4. The self-cleaning coating according to claim 1, wherein The preparation of the modified titanium dioxide comprises the following process: The titanium dioxide is dispersed in water, ammonia water is added to adjust the pH of the system to 8-8.5, and then the organic phosphonic acid compound is added, and ultrasonic heating stirring is performed at 150-200 W ultrasonic power and 70-80 ℃ temperature for 1-2 h. After the reaction is completed, filtration, washing, drying and grinding are performed to obtain the modified titanium dioxide.

5. The self-cleaning coating according to any one of claims 1 to 4, wherein The self-cleaning coating comprises the following components in parts by weight: The base emulsion is 90-100 parts, the modified titanium dioxide is 5-10 parts, the filler is 30-40 parts, the auxiliary agent is 4-7 parts, and the water is 15-20 parts.

6. The self-cleaning coating according to claim 5, characterized in that, The self-cleaning coating comprises the following components in parts by weight: The base emulsion is 95 parts, the modified titanium dioxide is 8.5 parts, the filler is 35 parts, the auxiliary agent is 5 parts, and the water is 17 parts.

7. The self-cleaning coating according to claim 5, wherein The base emulsion comprises at least one of an acrylic emulsion and a styrene-acrylic emulsion; And / or, the filler comprises at least one of calcium carbonate and kaolin; And / or, the auxiliary agent comprises at least one of a dispersing agent, a defoaming agent, a leveling agent and a thickening agent.

8. A method for producing the self-cleaning coating according to any one of claims 1 to 7, characterized in that, The preparation method of the self-cleaning coating comprises the following steps: The modified titanium dioxide is obtained; The modified titanium dioxide and the remaining components of the self-cleaning coating are mixed to obtain the self-cleaning coating.

9. Use of the self-cleaning coating of any one of claims 1-7 or the self-cleaning coating prepared by the preparation method of claim 8 in the preparation of a self-cleaning product.

10. The self-cleaning coating according to claim 9, characterized in that, The self-cleaning product comprises at least one of self-cleaning glass, self-cleaning steel and self-cleaning stone. The self-cleaning product comprises at least one of self-cleaning glass, self-cleaning steel and self-cleaning stone.

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