Composite coating, preparation method thereof and composite coating

Abstract

The invention discloses a composite coating, a preparation method thereof and a composite coating, and relates to the technical field of coatings. The composite coating is prepared from titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite and deionized water. According to the composite coating provided by the invention, cellulose and montmorillonite nanosheets form a compact micro-nano coating, so that the effect of isolating moisture and oxygen is achieved; a titanium dioxide photocatalytic sterilization function is combined with a high fluorine content and a cross-linked structure to endow the coating with a super-hydrophobic surface, and a self-cleaning function is synergistically realized. The composite coating provided by the invention has the triple characteristics of'green ', 'self-cleaning' and'antibacterial ', and has a wide application prospect in the wide fields of medical treatment and public health, food packaging and processing, building and home furnishing, marine antifouling and the like.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to a composite coating and its preparation method, and a composite coating layer. Background Technology

[0002] Polymer-based coatings are used almost everywhere due to their excellent protective properties, strong decorative properties, and wide applicability to various substrates, such as industrial corrosion protection, automotive industry, electronics and electrical appliances, and aerospace.

[0003] With consumers' growing demand for green and healthy products, the traditional coatings industry urgently needs to transform towards green, functional, and high-end products, thereby providing higher-value solutions for various industries. Among these, self-cleaning and antibacterial bio-based coatings represent an important future development direction for the coatings industry—green, functional, and intelligent. The research and development of self-cleaning and antibacterial bio-based coatings has profound significance and is a concrete manifestation of responding to global sustainable development strategies and health needs.

[0004] However, existing coatings are difficult to meet the requirements of being green, self-cleaning, and antibacterial at the same time. Summary of the Invention

[0005] In view of this, this application provides a composite coating and its preparation method, as well as a composite coating layer.

[0006] The embodiments of this application are implemented as follows: In the first aspect, the embodiments of this application provide a composite coating, comprising: titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water.

[0007] Optionally, in some embodiments of this application, the particle size of the titanium dioxide is 3nm~8nm;

[0008] The acidified montmorillonite includes montmorillonite modified with acid reagents;

[0009] The acidified montmorillonite has a layered structure, and the titanium dioxide is located in the layered structure;

[0010] The mass ratio of the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the montmorillonite, and the deionized water is (2~5):(70~80):(10~15):(5~10):(300~600).

[0011] Secondly, embodiments of this application also provide a method for preparing a composite coating, comprising the following steps:

[0012] It provides titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite and deionized water;

[0013] The titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water are mixed to obtain a composite coating.

[0014] Optionally, in some embodiments of this application, the mass ratio of the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the montmorillonite, and the deionized water is (2~5):(70~80):(10~15):(5~10):(300~600).

[0015] Optionally, in some embodiments of this application, the method for preparing the acidified montmorillonite includes the following steps:

[0016] Montmorillonite and a portion of the aforementioned deionized water are mixed to obtain a montmorillonite solution;

[0017] An acidic reagent is provided and mixed with the montmorillonite solution to adjust the pH value to acidic, thereby obtaining an acidified montmorillonite solution; the acidified montmorillonite solution includes acidified montmorillonite.

[0018] Optionally, in some embodiments of this application, the acidic reagent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid;

[0019] The pH value of the acidified montmorillonite solution is 2 to 2.5.

[0020] Optionally, in some embodiments of this application, the step of mixing the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the acidified montmorillonite, and the deionized water to obtain a composite coating includes:

[0021] The acidified montmorillonite solution and the titanium dioxide solution are mixed to carry out a first reaction to obtain a first mixture; wherein the titanium dioxide solution includes the titanium dioxide.

[0022] A sodium carboxymethyl cellulose solution and the bisphenol hexafluoroacetone diglycidyl ether are mixed to carry out a second reaction to obtain a second mixture; wherein the sodium carboxymethyl cellulose solution includes the sodium carboxymethyl cellulose.

[0023] The first mixture and the second mixture are mixed to obtain a composite coating.

[0024] Optionally, in some embodiments of this application, the reaction temperature of the first reaction is 30°C to 80°C; the reaction time of the first reaction is 20h to 60h.

[0025] The reaction temperature of the second reaction is 20℃~40℃; the reaction time of the second reaction is 2h~6h;

[0026] The method for preparing the composite coating after mixing the first mixture and the second mixture further includes: performing ultrasonic treatment; the temperature of the ultrasonic treatment is 20℃~40℃; and the time of the ultrasonic treatment is 0.5h~2h.

[0027] Thirdly, embodiments of this application also provide a composite coating, which is obtained by spraying a composite coating onto the surface of a substrate and then performing heat treatment; wherein the composite coating is the composite coating described above or a composite coating prepared by the preparation method described above.

[0028] Optionally, in some embodiments of this application, the thickness of the composite coating is 10 μm to 500 μm;

[0029] The heat treatment temperature is 30℃~80℃; the heat treatment time is 5h~20h.

[0030] The composite coating provided in this application uses titanium dioxide (which has photocatalytic antibacterial function) to assist in the exfoliation of montmorillonite in an acidic aqueous solution (titanium dioxide carries a positive charge on its surface under acidic conditions and can enter the interlayer of montmorillonite under electrostatic action), resulting in a solution rich in oligolayer montmorillonite nanosheets and nano-titanium dioxide. Then, sodium carboxymethyl cellulose and bisphenol hexafluoroacetone diglycidyl ether (high fluoride content forms a hydrophobic surface and provides self-cleaning ability) are pre-reacted to form a cellulose microgel aqueous solution. The cellulose microgel is then mixed with the montmorillonite / titanium dioxide solution to form the composite coating. The cellulose and montmorillonite nanosheets form a dense micro-nano coating, which isolates moisture and oxygen. The photocatalytic bactericidal function of titanium dioxide, combined with the high fluoride content and cross-linking structure, gives the coating a superhydrophobic surface, synergistically achieving the self-cleaning function.

[0031] The composite coating provided in this application has the triple characteristics of "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of a method for preparing a composite coating provided in an embodiment of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0035] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0036] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0037] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0038] Various embodiments of this application 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 this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges 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 referred range.

[0039] The structural formulas and molecular weights of some of the chemical reagents used in this application are described below:

[0040] Montmorillonite: Al2H2O 12 Si4, molecular weight = 360.31, Adamas brand, available for purchase from the Exploration Chemical Reagents Platform;

[0041] Sodium carboxymethyl cellulose: 300 mPa·s~800 mPa·s, Adamas Life brand, available for purchase from the Exploration Chemical Reagents platform;

[0042] Bisphenol hexafluoroacetone diglycidyl ether: Molecular weight = 448.36, available for purchase from Shanghai Fluorine Technology Co., Ltd.

[0043] The technical solution of this application is as follows:

[0044] In a first aspect, embodiments of this application provide a composite coating comprising: titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water.

[0045] The composite coating provided in this application obtains a solution rich in oligolayer montmorillonite nanosheets and nano-titanium dioxide through titanium dioxide (which has photocatalytic antibacterial function) and acidified montmorillonite. Then, sodium carboxymethyl cellulose and bisphenol hexafluoroacetone diglycidyl ether (high fluoride content forms a hydrophobic surface and provides self-cleaning ability) are pre-reacted to form a cellulose microgel aqueous solution. The cellulose microgel is then mixed with the montmorillonite / titanium dioxide solution to form the composite coating. The cellulose and montmorillonite nanosheets form a dense micro-nano coating, which isolates moisture and oxygen. The photocatalytic bactericidal function of titanium dioxide, combined with the high fluoride content and cross-linking structure, gives the coating a superhydrophobic surface and synergistically achieves the self-cleaning function.

[0046] The composite coating provided in this application has the triple characteristics of "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling.

[0047] In some embodiments, the acidified montmorillonite comprises montmorillonite modified with an acidic reagent. It should be noted that montmorillonite has a layered structure, and hydrated hydrogen ions in the aqueous solution of the acidic reagent can enter between the layers of montmorillonite, displacing the exchangeable cations between the layers, slightly increasing the interlayer spacing and weakening the interlayer forces, which is beneficial for the insertion of titanium dioxide.

[0048] Furthermore, the acidic reagent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; when the acidic reagent is selected from hydrochloric acid, the concentration of the hydrochloric acid can be 0.1 mol / L.

[0049] In some embodiments, in the composite coating, the mass ratio of titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, montmorillonite, and deionized water is (2~5):(70~80):(10~15):(5~10):(300~600); for example, it can be 2:70:10:5:300, 3:73:12:6:380, 5:78:14:8:560, or any range between the above two ratios; within the mass ratio range described above, the proportion of each component is appropriate, which can effectively improve the performance of the composite coating.

[0050] In some embodiments, the acidified montmorillonite has a layered structure, and the titanium dioxide is located within the layered structure.

[0051] In some embodiments, the particle size of the titanium dioxide is 3nm to 8nm; for example, it can be 3nm, 5nm, 7nm, 8nm or any two of the above values; within the particle size range described above, it is beneficial for the titanium dioxide to enter the layered structure of the acidified montmorillonite.

[0052] The composite coating provided in this application has the triple characteristics of "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling.

[0053] Secondly, please refer to Figure 1 This application provides a method for preparing a composite coating, comprising the following steps:

[0054] Step S11: Provide titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water;

[0055] Step S12: Mix the titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water to obtain a composite coating.

[0056] The method for preparing the composite coating provided in this application involves using titanium dioxide (which has photocatalytic antibacterial function) to assist in the exfoliation of acidified montmorillonite (titanium dioxide carries a positive charge on its surface under acidic conditions and can enter the interlayer of montmorillonite under electrostatic action), resulting in a solution rich in oligolayer montmorillonite nanosheets and nano-titanium dioxide. Then, sodium carboxymethyl cellulose and bisphenol hexafluoroacetone diglycidyl ether (high fluoride content forms a hydrophobic surface and provides self-cleaning ability) are pre-reacted to form a cellulose microgel aqueous solution. The cellulose microgel is then mixed with the montmorillonite / titanium dioxide solution to form the composite coating. The cellulose and montmorillonite nanosheets form a dense micro-nano coating, which isolates moisture and oxygen. The photocatalytic bactericidal function of titanium dioxide, combined with the high fluoride content and cross-linked structure, gives the coating a superhydrophobic surface, synergistically achieving the self-cleaning function.

[0057] The composite coating prepared by the method provided in this application has the triple characteristics of "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling.

[0058] In step S11:

[0059] In some embodiments, the method for preparing the acidified montmorillonite includes the following steps:

[0060] Step S111: Provide montmorillonite and a portion of the deionized water, mix them to obtain a montmorillonite solution;

[0061] Step S112: Provide an acidic reagent, mix it with the montmorillonite solution, and adjust the pH value to acidic to obtain an acidified montmorillonite solution; the acidified montmorillonite solution includes acidified montmorillonite.

[0062] It should be noted that adjusting the pH value to acidic means adjusting the pH value to less than 7.

[0063] In some embodiments, the acidic reagent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; when the acidic reagent is selected from hydrochloric acid, the concentration of the hydrochloric acid may be 0.1 mol / L.

[0064] In some embodiments, the mass ratio of montmorillonite to a portion of the deionized water in the montmorillonite solution is (5~10):(60~300), for example, it can be 5:90, 6:180, 7:200, 8:210, 9:250, 10:300, or any range between two of the above ratios. Within the mass ratio range described above, the ratio of montmorillonite to the deionized water is suitable and beneficial for the uniform dispersion of montmorillonite in the deionized water.

[0065] In some embodiments, the montmorillonite and a portion of the deionized water can be thoroughly mixed by stirring; further, the stirring is selected from one or more of mechanical stirring, magnetic stirring, and ultrasonic stirring; when the stirring is magnetic stirring, the magnetic stirring time can be 6h to 12h.

[0066] In some embodiments, in order to control the rate of pH adjustment, the acidic reagent can be added dropwise to the montmorillonite solution, and the pH value can be monitored in real time until the pH value becomes acidic, thus obtaining the acidified montmorillonite solution.

[0067] In some embodiments, the pH value can be adjusted to 2-2.5 to obtain the acidified montmorillonite solution.

[0068] In some embodiments, the acidified montmorillonite has a layered structure. After obtaining the acidified montmorillonite solution, the solution can be stirred to allow hydrated hydrogen ions (H3O) to hydrate. + The first to enter the interlayer of the acidified montmorillonite displaces the interlayer exchangeable cations, slightly increasing the interlayer spacing and weakening the interlayer forces, thus creating favorable conditions for the subsequent insertion of titanium dioxide.

[0069] In step S12:

[0070] In some embodiments, mixing the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the acidified montmorillonite, and the deionized water to obtain a composite coating includes the following steps:

[0071] Step S121: Mix the acidified montmorillonite solution and the titanium dioxide solution to carry out a first reaction and obtain a first mixture; wherein the titanium dioxide solution includes the titanium dioxide.

[0072] Step S122: Mix the sodium carboxymethyl cellulose solution and the bisphenol hexafluoroacetone diglycidyl ether to carry out a second reaction to obtain a second mixture; wherein the sodium carboxymethyl cellulose solution includes the sodium carboxymethyl cellulose.

[0073] Step S123: Mix the first mixture and the second mixture to obtain a composite coating.

[0074] In step S121:

[0075] In some embodiments, the titanium dioxide solution is obtained by mixing the titanium dioxide with a portion of the deionized water.

[0076] Furthermore, the titanium dioxide can be uniformly dispersed in the deionized water by conventional techniques in the art, such as stirring and ultrasonic treatment; when ultrasonic treatment is performed, the ultrasonic treatment time can be 0.5h to 3h.

[0077] In some embodiments, the mass ratio of titanium dioxide to a portion of the deionized water in the titanium dioxide solution is (2~5):(20~50), for example, it can be 2:11, 3:24, 4:32, 5:50, or any range between two of the above ratios. Within the mass ratio range described above, the ratio of titanium dioxide to the deionized water is suitable and beneficial for the uniform dispersion of titanium dioxide in the deionized water.

[0078] In some embodiments, in the first reaction, the mass ratio of montmorillonite to titanium dioxide is (5~10):(2~5), for example, it can be 5:2, 6:3, 7:3, 9:5, or any range between two of the above ratios. Within the mass ratio range described above, the ratio of montmorillonite to titanium dioxide is suitable, which facilitates the entry of titanium dioxide into the montmorillonite interlayer, resulting in a first solution rich in oligolayer montmorillonite and nano-titanium dioxide.

[0079] In some embodiments, the first reaction can be promoted by stirring and heating.

[0080] In some embodiments, the reaction temperature of the first reaction is 30°C to 80°C, for example, it can be 30°C, 50°C, 70°C, 80°C or any two of the above values; the reaction time of the first reaction is 20h to 60h, for example, it can be 24h, 36h, 43h, 48h, 52h or any two of the above values; under the reaction conditions described above, it is beneficial for the first reaction to proceed fully and improve the reaction yield.

[0081] In some embodiments, after the first reaction, the reaction solution of the first reaction can be transferred to an ice-water bath for ultrasonic treatment to obtain a first mixture. Ultrasonic treatment can effectively prevent the titanium dioxide from agglomerating, and at the same time, the ice-water bath can effectively absorb the heat generated by ultrasonic treatment, avoiding structural damage caused by local overheating.

[0082] In step S122:

[0083] In some embodiments, the sodium carboxymethyl cellulose solution is obtained by mixing the sodium carboxymethyl cellulose in a portion of the deionized water.

[0084] In some embodiments, the mass ratio of sodium carboxymethyl cellulose to a portion of the deionized water in the sodium carboxymethyl cellulose solution is (70-80):(120-250), for example, it can be 70:120, 73:200, 80:250, or any range between two of the above ratios. Within the mass ratio range described above, the ratio of sodium carboxymethyl cellulose to the deionized water is suitable and facilitates the complete dissolution of sodium carboxymethyl cellulose in the deionized water.

[0085] It should be noted that the deionized water in the acidified montmorillonite solution, titanium dioxide solution, and sodium carboxymethyl cellulose solution together constitutes all the deionized water in the composite coating.

[0086] In some embodiments, in the second reaction, the mass ratio of sodium carboxymethyl cellulose to bisphenol hexafluoroacetone diglycidyl ether is (70-80):(10-15), for example, it can be 70:10, 73:12, 76:12, 78:14, 80:15, or any range between two of the above ratios. Within the mass ratio range described above, the ratio of sodium carboxymethyl cellulose to bisphenol hexafluoroacetone diglycidyl ether is suitable and conducive to the full progress of the second reaction.

[0087] In some embodiments, the reaction temperature of the second reaction is room temperature, for example, it can be 20℃~40℃; the reaction time of the second reaction is 2h~6h, for example, it can be 2h, 4h, 6h or any two of the above values; under the reaction conditions described above, it is beneficial for the carboxymethyl group of the sodium carboxymethyl cellulose to undergo a nucleophilic addition reaction with the epoxy group of the bisphenol hexafluoroacetone diglycidyl ether.

[0088] In step S123:

[0089] In some embodiments, after mixing the first mixture and the second mixture, the method further includes: performing ultrasonic treatment.

[0090] In some embodiments, the temperature of the ultrasonic treatment is room temperature, for example, 20°C to 40°C; the time of the ultrasonic treatment is 0.5h to 2h, for example, 0.5h, 1h, 2h or any two of the above values; under the conditions described above, it is beneficial for the first mixture and the second mixture to be fully mixed.

[0091] The method for preparing the composite coating provided in this application involves using titanium dioxide (which has photocatalytic antibacterial function) in an acidic aqueous solution to assist in the exfoliation of montmorillonite (titanium dioxide carries a positive charge on its surface under acidic conditions and can enter the interlayer of montmorillonite under electrostatic action), resulting in a solution rich in oligolayer montmorillonite nanosheets and nano-titanium dioxide. Then, sodium carboxymethyl cellulose and bisphenol hexafluoroacetone diglycidyl ether (high fluoride content forms a hydrophobic surface and provides self-cleaning ability) are pre-reacted to form a cellulose microgel aqueous solution. The cellulose microgel is then mixed with the montmorillonite / titanium dioxide solution to form the composite coating. The cellulose and montmorillonite nanosheets form a dense micro-nano coating, which isolates moisture and oxygen. The photocatalytic bactericidal function of titanium dioxide, combined with the high fluoride content and cross-linked structure, gives the coating a superhydrophobic surface, synergistically achieving the self-cleaning function.

[0092] Secondly, this application provides a composite coating, which is obtained by spraying a composite coating onto the surface of a substrate and then performing heat treatment; wherein the composite coating is the aforementioned composite coating or a composite coating prepared by the aforementioned preparation method.

[0093] In some embodiments, the thickness of the composite coating is 10 μm to 500 μm.

[0094] In some embodiments, the temperature of the heat treatment is 30°C to 80°C, for example, 30°C, 50°C, 70°C, 80°C or any two of the above values; the time of the heat treatment is 5h to 20h, for example, 4h, 6h, 12h, 16h, 20h or any two of the above values; under the heat treatment conditions described above, it is beneficial for the carboxymethyl cellulose in the composite coating to further crosslink and form a cured network.

[0095] The composite coating provided in this application has the triple characteristics of being "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling.

[0096] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0097] Example 1

[0098] This embodiment provides a composite coating, and the preparation method of the composite coating includes the following steps:

[0099] Step 1: Weigh 5g of montmorillonite and 200g of deionized water into a 1000mL beaker. Stir magnetically at 25℃ for 6 hours to ensure the montmorillonite is fully hydrated and swollen, forming a uniform milky white solution. While continuously stirring, add dilute hydrochloric acid (0.1mol / L) dropwise, monitoring the pH in real time with a pH meter, and adjust the pH of the solution to 2.3 to obtain an acidified montmorillonite solution. Continue stirring for 2 hours. Take 3g of anatase nano-titanium dioxide (5nm, purchased from Nanjing Baoket New Materials Co., Ltd.) and 30g of deionized water into a 50mL single-necked flask, and sonicate at 25℃ for 1 hour to obtain a titanium dioxide solution. Slowly add the titanium dioxide solution dropwise to the acidified montmorillonite solution while stirring vigorously. Transfer the mixed solution to a 70℃ water bath and stir magnetically continuously for 28 hours. The intercalation product after the reaction was transferred to an ice-water bath and ultrasonically treated with a probe-type ultrasonic machine (power: 400W, ultrasonic time: 30 minutes) to obtain a solution rich in oligolayer montmorillonite and nano titanium dioxide, namely the first mixture.

[0100] Step 2: Weigh 80g of sodium carboxymethyl cellulose and 200g of deionized water and add them to a 500mL three-necked flask. Stir at 25°C until the sodium carboxymethyl cellulose is completely dissolved. Then add 12g of bisphenol hexafluoroacetone diglycidyl ether and stir at 25°C for 4 hours to obtain a cellulose microgel aqueous solution, which is the second mixture. Then add the first mixture obtained in Step 1 to the three-necked flask and sonicate at 25°C for 1 hour while keeping the mixture mechanically stirred to obtain the composite coating.

[0101] Example 2

[0102] This embodiment is basically the same as Embodiment 1, except that the amount of montmorillonite used in step 1 is 8g.

[0103] Example 3

[0104] This embodiment is basically the same as Embodiment 1, except that the amount of montmorillonite used in step 1 is 10g.

[0105] Example 4

[0106] This embodiment is basically the same as Embodiment 1, except that the amount of montmorillonite used in step 1 is 8g and the amount of anatase nano titanium dioxide used is 5g.

[0107] Example 5

[0108] This embodiment is basically the same as Embodiment 1, except that in step 1, the amount of montmorillonite is 8g and the amount of anatase nano-titanium dioxide is 5g; and in step 2, the amount of bisphenol hexafluoroacetone diglycidyl ether is 15g.

[0109] Comparative Example

[0110] Commercially available bio-based polyurethane spray coating, purchased from Fenyangtang (Shanghai) Industrial Co., Ltd.

[0111] The adhesive properties, self-cleaning properties, antibacterial properties and barrier properties of the composite coatings provided in Examples 1-5 and the comparative examples were tested. The test results are shown in Table 1.

[0112] The adhesion strength of the coating was tested using a cross-cut test, according to ASTM D3359 Method B. Specifically, the coating was sprayed onto the aluminum substrate surface, and a 2mm × 2mm grid was cut into the coating surface using a multi-bladed tool, the cuts penetrating the substrate. Debris was then removed with a soft brush, and adhesive tape was pressed firmly onto the grid area and quickly peeled off at a 180° angle. Finally, the extent of coating peeling in the grid area was observed under a microscope. Grade 0 indicates completely smooth edges with no peeling (best); Grade 5 indicates a peeling area greater than 65% (worst).

[0113] The water contact angle test was performed in accordance with standard ISO 19403.

[0114] The self-cleaning ability test is conducted according to the standard GB / T23761-2020 "Test Method for Self-Cleaning Performance of Photocatalytic Materials and Products". The self-cleaning ability of the coating is evaluated by measuring the degradation rate of methylene blue dye after the coating is placed under natural light for 24 hours.

[0115] Antimicrobial performance testing was performed according to standard ISO 22196. A certain concentration of Staphylococcus aureus solution was dropped onto the coating and a sterile glass slide. After incubation under natural light for 24 hours, the bacterial solution was washed off with a neutralization solution, and viable bacteria were counted. C0 represents the number of bacteria on the sterile glass slide, and C... x It is the number of bacteria on each coating; sterilization rate (%) = (C0 - C) x ) / C0*100%.

[0116] The water vapor transmission rate test was performed according to standard ISO 15106-3 (cup method); specifically, the coating was prepared on a porous nanofiltration membrane with r=10cm and cut, and sealed in the mouth of a test cup containing deionized water (permeable); the cup was placed in a constant temperature and humidity chamber, weighed periodically, and the water vapor transmission rate per unit time and per unit area was calculated.

[0117] The oxygen permeability test was performed according to the standard ASTM D3985 (coulometric method). Specifically, the coating was prepared on a porous nanofiltration membrane with r=10cm and cut. The coating sample was placed in the test chamber to separate two environments. High-purity oxygen flowed on one side and N2 flowed on the other side. The oxygen that permeated through was carried to the sensor by the carrier gas for detection.

[0118] Table 1

[0119] name Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example Adhesion grade Level 0 Level 0 Level 0 Level 0 Level 0 Level 1 Water contact angle (°) 103 114 126 117 135 68 Methylene blue degradation rate (%) 85 82 80 96 95 15 Sterilization rate (%) 90 88 85 98 99 18 Water vapor transmission rate (g / (m²·day)) 85 66 53 69 57 780 Oxygen permeability (cm³ / (m²·day·atm)) 112 87 61 83 64 1340

[0120] From the test data above, we can see that:

[0121] Benefiting from the chemical cross-linking network formed by the nucleophilic addition reaction between carboxymethyl and epoxy groups, the composite coating of this application exhibits high cohesive energy, thus demonstrating excellent adhesive strength. Simultaneously, the high-fluorine cross-linking agent significantly enhances the hydrophobic properties of the composite coating. Combined with the photocatalytic degradation of pollutants and bacteria by nano-titanium dioxide, the composite coating exhibits excellent self-cleaning and antibacterial functions. Furthermore, the oligolayer montmorillonite forms a dense barrier layer during the coating curing stage. Compared to commercially available bio-based polyurethane spray coatings, the composite coating prepared by this application exhibits exceptional barrier properties against both water vapor and oxygen.

[0122] The composite coating prepared by this invention has the triple characteristics of "green", "self-cleaning" and "antibacterial", and has broad application prospects in a wide range of fields such as medical and health care, food packaging and processing, building and home furnishing, and marine antifouling.

[0123] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composite coating, characterized in that, include: Titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water.

2. The composite coating according to claim 1, characterized in that, The particle size of the titanium dioxide is 3nm~8nm; The acidified montmorillonite includes montmorillonite modified with acid reagents; The acidified montmorillonite has a layered structure, and the titanium dioxide is located in the layered structure; The mass ratio of the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the montmorillonite, and the deionized water is (2~5):(70~80):(10~15):(5~10):(300~600).

3. A method for preparing a composite coating, characterized in that, Includes the following steps: It provides titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite and deionized water; The titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water are mixed to obtain a composite coating.

4. The preparation method according to claim 3, characterized in that, The mass ratio of the titanium dioxide, the sodium carboxymethyl cellulose, the bisphenol hexafluoroacetone diglycidyl ether, the montmorillonite, and the deionized water is (2~5):(70~80):(10~15):(5~10):(300~600).

5. The preparation method according to claim 3, characterized in that, The preparation method of the acidified montmorillonite includes the following steps: Montmorillonite and a portion of the aforementioned deionized water are mixed to obtain a montmorillonite solution; An acidic reagent is provided and mixed with the montmorillonite solution to adjust the pH value to acidic, thereby obtaining an acidified montmorillonite solution; The acidified montmorillonite solution includes acidified montmorillonite.

6. The preparation method according to claim 5, characterized in that, The acidic reagent is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; The pH value of the acidified montmorillonite solution is 2 to 2.

5.

7. The preparation method according to claim 5, characterized in that, The process of mixing the titanium dioxide, sodium carboxymethyl cellulose, bisphenol hexafluoroacetone diglycidyl ether, acidified montmorillonite, and deionized water to obtain a composite coating comprises: The acidified montmorillonite solution and the titanium dioxide solution are mixed to carry out a first reaction to obtain a first mixture; wherein the titanium dioxide solution includes the titanium dioxide. A sodium carboxymethyl cellulose solution and the bisphenol hexafluoroacetone diglycidyl ether are mixed to carry out a second reaction to obtain a second mixture; wherein the sodium carboxymethyl cellulose solution includes the sodium carboxymethyl cellulose. The first mixture and the second mixture are mixed to obtain a composite coating.

8. The preparation method according to claim 7, characterized in that, The reaction temperature of the first reaction is 30℃~80℃; the reaction time of the first reaction is 20h~60h; The reaction temperature of the second reaction is 20℃~40℃; the reaction time of the second reaction is 2h~6h; The method for preparing the composite coating after mixing the first mixture and the second mixture further includes: performing ultrasonic treatment; the temperature of the ultrasonic treatment is 20℃~40℃; and the time of the ultrasonic treatment is 0.5h~2h.

9. A composite coating, characterized in that, The composite coating is obtained by spraying a composite coating onto the surface of a substrate and then subjecting it to heat treatment; wherein the composite coating is the composite coating according to any one of claims 1-2 or the composite coating prepared by any one of the preparation methods according to claims 3-8.

10. The composite coating according to claim 9, characterized in that, The thickness of the composite coating is 10μm~500μm; The heat treatment temperature is 30℃~80℃; the heat treatment time is 5h~20h.

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