Silicate antibacterial coating and method for preparing the same

Abstract

The application discloses a silicate antibacterial coating, which comprises the following raw materials in parts by weight: inorganic silicate 100 parts, antibacterial modifier 1-30 parts, silica sol 10-100 parts, dispersing agent 1-10 parts, thickening agent 0-30 parts, defoaming agent 0-10 parts, inorganic filler 10-30 parts, silicone-acrylate emulsion 0-30 parts and water 1-100 parts. A preparation method specifically comprises the following steps: (1) weighing each raw material; (2) uniformly mixing the inorganic silicate, the antibacterial modifier, the silica sol, the dispersing agent, the thickening agent, the defoaming agent, the inorganic filler and the silicone-acrylate emulsion; (3) adding water and uniformly stirring; (4) grinding and filtering, and the silicate antibacterial coating is obtained. The application realizes long-acting antibacterial performance of the coating, enhances the hydrophobic performance of the coating and expands the application prospect of the coating in a humid environment.

Description

Technical Field

[0001] This invention relates to the field of architectural coatings technology, and more specifically to a silicate antibacterial coating and its preparation method. Background Technology

[0002] Inorganic silicate coatings, commonly known as inorganic mineral coatings, are mainly composed of liquid potassium silicate and inorganic metal oxides. Using natural inorganic minerals as raw materials, these coatings are free of toxic and harmful substances. They can decompose formaldehyde, purify the air, and eliminate the worries of indoor pollution from formaldehyde, benzene, and other toxic and harmful substances. This is of great benefit to patients with weak immune systems and to medical equipment, medical experiments, and laboratories that require a high degree of cleanliness.

[0003] The antibacterial properties of materials have become a hot topic of concern. In residential buildings, walls account for the largest area, making them the final destination for bacteria and viruses in indoor air. Hospitals are breeding grounds for bacteria; studies show that the density of pathogens in the air and on walls in living spaces, hospitals, schools, kindergartens, hotels, and other similar locations is far higher than in outdoor areas. If not effectively controlled, this can easily lead to large-scale cross-infection.

[0004] Therefore, how to develop a silicate antibacterial coating is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a silicate antibacterial coating and its preparation method, which enhances the antibacterial properties of the coating by using an organofluorosilicone antibacterial modifier, thereby solving the problem of poor water resistance of inorganic silicate coatings in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A silicate antibacterial coating comprises the following raw materials in parts by weight: 100 parts inorganic silicate, 1-30 parts antibacterial modifier, 10-100 parts silica sol, 1-10 parts dispersant, 0-30 parts thickener, 0-10 parts defoamer, 10-30 parts inorganic filler, 0-30 parts silicone-acrylic emulsion, and 1-100 parts water.

[0008] The preferred composition is: 100 parts inorganic silicate, 30 parts antibacterial modifier, 10 parts silica sol, 5 parts dispersant, 20 parts thickener, 2 parts defoamer, 10 parts inorganic filler, 5 parts silicone-acrylic emulsion, and 30 parts water.

[0009] Furthermore, the aforementioned inorganic silicate is potassium silicate.

[0010] The further beneficial effect of the above-mentioned method is that, among inorganic silicates, sodium silicate has poor water resistance and suffers from severe salting-out. While lithium silicate has good performance, it is expensive. In contrast, potassium silicate has excellent overall performance and a high cost-effectiveness; therefore, potassium silicate was chosen as the film-forming substance for inorganic silicate coatings.

[0011] Furthermore, the aforementioned antibacterial modifier is an active silane antibacterial modifier with a side chain containing sulfonium ions, and its structural formula is as follows: Where m = 0-3, n = 0-18, preferably m = 0, n = 1.

[0012] The further beneficial effect of the above-mentioned method is that, compared with quaternary ammonium salts, thionium ions have a more concentrated charge center, and their antibacterial properties are superior to those of quaternary ammonium salts.

[0013] Furthermore, the preparation method of the above-mentioned antibacterial modifier is as follows:

[0014] (1) Vinylalkoxysilane and ethanethiol were dissolved in tetrahydrofuran and subjected to ultraviolet catalysis under nitrogen protection to obtain (2-(ethylthio)ethyl)trialkoxysilane;

[0015] (2) Further utilize the nucleophilic reaction of side group sulfides with fluorinated iodine to dissolve (2-(ethio)ethyl)trialkoxysilane and fluorinated iodine in tetrahydrofuran, add an alkaline catalyst, and react overnight to obtain an antibacterial modifier.

[0016] Furthermore, the mass ratio of the aforementioned vinylalkoxysilane, ethanethiol, and tetrahydrofuran was 1.1 g: 1.2 g: 20 mL; the ultraviolet light wavelength for ultraviolet catalysis was 365 nm, and the time was 2 h.

[0017] The further beneficial effect of the above method is that, using tetrahydrofuran as a solvent, vinylalkoxysilane and ethanethiol undergo a click chemical reaction under ultraviolet light to synthesize (2-(ethylthio)ethyl)trialkoxysilane.

[0018] Furthermore, the aforementioned fluorinated iodoalkane is 1,1,1,2,2-pentafluoro-3-iodopropane; the base catalyst is triethylamine; and the mass ratio of (2-(ethylthio)ethyl)trialkoxysilane, fluorinated iodoalkane, tetrahydrofuran, and base catalyst is 1 g:2 g:20 mL:0.2 mL.

[0019] The further beneficial effect of the above-mentioned method is that, by utilizing the I-containing nucleophilic reaction, hydrophobic F atoms are introduced while constructing the thionium antibacterial salt, thereby improving the water resistance of the product.

[0020] Furthermore, the dispersant is at least one of acrylic acid copolymer, sodium phosphate, potassium phosphate, sodium carboxylate, and potassium carboxylate, preferably sodium hexafluorophosphate.

[0021] Furthermore, the thickener is at least one selected from silicate, alumina, bentonite, aluminum silicate, carboxymethyl cellulose, chitosan, and sodium alginate, preferably carboxymethyl cellulose.

[0022] Furthermore, the aforementioned defoamer is at least one selected from silicone oil, aminosulfate, glycine, sodium silicate, magnesium silicate, aluminum hydroxide, magnesia, and zinc oxide, preferably zinc oxide.

[0023] Furthermore, the aforementioned inorganic filler is at least one of kaolin, talc, silica lime, mica, clay, and asbestos, preferably kaolin.

[0024] A method for preparing a silicate antibacterial coating specifically includes the following steps:

[0025] (1) Weigh each raw material according to the above-mentioned parts by weight of silicate antibacterial coating;

[0026] (2) Inorganic silicate, antibacterial modifier, silica sol, dispersant, thickener, defoamer, inorganic filler and silicone-acrylic emulsion are mixed evenly to obtain a mixture;

[0027] (3) Add water to the mixture and stir well to obtain a slurry;

[0028] (4) Grind and filter the slurry to obtain silicate antibacterial coating.

[0029] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention first designs and prepares a thioonium salt antibacterial modifier. By retaining the terminal active siloxane and utilizing silane hydrolysis and condensation, the covalent bond between the organic modifier and the inorganic silicate coating is strengthened, enhancing the film-forming behavior of the material and achieving long-lasting antibacterial performance of the coating. Simultaneously, in the molecular design of the antibacterial modifier, F-containing functional groups are introduced into the side groups, enhancing the hydrophobic properties of the coating and expanding its application prospects in humid environments. Detailed Implementation

[0031] 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.

[0032] Example 1

[0033] The silicate antibacterial coating comprises the following raw materials by weight: 100g potassium silicate, 10g antibacterial modifier, 10g silica sol, 5g sodium hexafluorophosphate, 20g carboxymethyl cellulose, 2g zinc oxide, 10g kaolin, 5g silicone-acrylic emulsion, and 30g water.

[0034] The antibacterial modifier is an active silane antibacterial modifier with a side chain containing sulfonium ions, and its structural formula is as follows:

[0035] ;

[0036] The preparation method of the antibacterial modifier is as follows:

[0037] (1) Dissolve 1.1g vinylalkoxysilane and 1.2g ethanethiol in 20mL tetrahydrofuran, and catalyze the mixture under nitrogen protection in a UV box with a wavelength of 365nm for 2h to obtain (2-(ethio)ethyl)trialkoxysilane.

[0038] (2) Dissolve 1g of (2-(ethio)ethyl)trialkoxysilane and 2g of 1,1,1,2,2-pentafluoro-3-iodopropane in 20mL of tetrahydrofuran, add 0.2mL of triethylamine, and react overnight to obtain an antibacterial modifier;

[0039] The preparation method of the above-mentioned silicate antibacterial coating specifically includes the following steps:

[0040] (1) Weigh each raw material according to the weight of the above silicate antibacterial coating;

[0041] (2) Mix potassium silicate, antibacterial modifier, silica sol, sodium hexafluorophosphate, carboxymethyl cellulose, zinc oxide, kaolin and silicone-acrylic emulsion evenly to obtain a mixture;

[0042] (3) Add water to the mixture and stir well to obtain a slurry;

[0043] (4) Grind and filter the slurry to obtain silicate antibacterial coating.

[0044] Example 2

[0045] The silicate antibacterial coating comprises the following raw materials by weight: 100g potassium silicate, 20g antibacterial modifier, 10g silica sol, 5g sodium hexafluorophosphate, 20g carboxymethyl cellulose, 2g zinc oxide, 10g kaolin, 5g silicone-acrylic emulsion, and 30g water.

[0046] The antibacterial modifier is an active silane antibacterial modifier with a side chain containing sulfonium ions, and its structural formula is as follows:

[0047] ;

[0048] The preparation method of the antibacterial modifier is as follows:

[0049] (1) Dissolve 1.1g vinylalkoxysilane and 1.2g ethanethiol in 20mL tetrahydrofuran, and catalyze the mixture under nitrogen protection in a UV box with a wavelength of 365nm for 2h to obtain (2-(ethio)ethyl)trialkoxysilane.

[0050] (2) Dissolve 1g of (2-(ethio)ethyl)trialkoxysilane and 2g of 1,1,1,2,2-pentafluoro-3-iodopropane in 20mL of tetrahydrofuran, add 0.2mL of triethylamine, and react overnight to obtain an antibacterial modifier;

[0051] The preparation method of the above-mentioned silicate antibacterial coating specifically includes the following steps:

[0052] (1) Weigh each raw material according to the weight of the above silicate antibacterial coating;

[0053] (2) Mix potassium silicate, antibacterial modifier, silica sol, sodium hexafluorophosphate, carboxymethyl cellulose, zinc oxide, kaolin and silicone-acrylic emulsion evenly to obtain a mixture;

[0054] (3) Add water to the mixture and stir well to obtain a slurry;

[0055] (4) Grind and filter the slurry to obtain silicate antibacterial coating.

[0056] Example 3

[0057] The silicate antibacterial coating comprises the following raw materials by weight: 100g potassium silicate, 30g antibacterial modifier, 10g silica sol, 5g sodium hexafluorophosphate, 20g carboxymethyl cellulose, 2g zinc oxide, 10g kaolin, 5g silicone-acrylic emulsion, and 30g water.

[0058] The antibacterial modifier is an active silane antibacterial modifier with a side chain containing sulfonium ions, and its structural formula is as follows:

[0059] ;

[0060] The preparation method of the antibacterial modifier is as follows:

[0061] (1) Dissolve 1.1g vinylalkoxysilane and 1.2g ethanethiol in 20mL tetrahydrofuran, and catalyze the mixture under nitrogen protection in a UV box with a wavelength of 365nm for 2h to obtain (2-(ethio)ethyl)trialkoxysilane.

[0062] (2) Dissolve 1g of (2-(ethio)ethyl)trialkoxysilane and 2g of 1,1,1,2,2-pentafluoro-3-iodopropane in 20mL of tetrahydrofuran, add 0.2mL of triethylamine, and react overnight to obtain an antibacterial modifier;

[0063] The preparation method of the above-mentioned silicate antibacterial coating specifically includes the following steps:

[0064] (1) Weigh each raw material according to the weight of the above silicate antibacterial coating;

[0065] (2) Mix potassium silicate, antibacterial modifier, silica sol, sodium hexafluorophosphate, carboxymethyl cellulose, zinc oxide, kaolin and silicone-acrylic emulsion evenly to obtain a mixture;

[0066] (3) Add water to the mixture and stir well to obtain a slurry;

[0067] (4) Grind and filter the slurry to obtain silicate antibacterial coating.

[0068] Comparative Example

[0069] The silicate antibacterial coating comprises the following raw materials by weight: 100g potassium silicate, 10g methyltrimethoxysilane, 10g silica sol, 5g sodium hexafluorophosphate, 20g carboxymethyl cellulose, 2g zinc oxide, 10g kaolin, 5g silicone-acrylic emulsion, and 30g water.

[0070] The preparation method of the above-mentioned silicate antibacterial coating specifically includes the following steps:

[0071] (1) Weigh each raw material according to the weight of the above silicate antibacterial coating;

[0072] (2) Mix potassium silicate, methyltrimethoxysilane, silica sol, sodium hexafluorophosphate, carboxymethyl cellulose, zinc oxide, kaolin and silicone-acrylic emulsion evenly to obtain a mixture;

[0073] (3) Add water to the mixture and stir well to obtain a slurry;

[0074] (4) Grind and filter the slurry to obtain silicate antibacterial coating.

[0075] Performance testing

[0076] The contact angle and antibacterial inhibition rate of the silicate antibacterial coatings prepared in the comparative examples and Examples 1-3 were tested respectively. The results are shown in Table 1.

[0077] The contact angle test method is as follows: apply silicate antibacterial coating to the surface of the substrate, cure the coating into a film at room temperature, drop water on the coating surface, and use an SDC-100S contact angle meter to test the static contact angle of the coating.

[0078] The method for testing the antibacterial inhibition rate was as follows: First, bacterial suspensions of *Escherichia coli* and *Staphylococcus aureus* were incubated in a 37°C constant-temperature shaking incubator for 12 hours. Then, bacterial suspensions coated with silicate antibacterial coating were placed on a glass slide containing 20 mL of bacteria, and the samples were incubated in a 37°C aerobic growth incubator for 12 hours. The above procedure was repeated for the blank control. Next, 1 mL of co-cultured bacterial suspension from each sample was aspirated and diluted 1000-fold with sterile water. Finally, 20 μL of the diluted bacterial suspension was aspirated, evenly dispersed on a solid culture medium, and incubated again at 37°C for 12 hours. The bacterial growth after incubation was recorded.

[0079] Table 1. Static contact angle and antibacterial inhibition rate of silicate antibacterial coatings in comparative examples and Examples 1-3.

[0080]

[0081]

[0082] As shown in Table 1, compared with the comparative examples, the static contact angle and antibacterial inhibition rate of the silicate antibacterial coatings of Examples 1-3 of the present invention are significantly improved.

[0083] The above tests demonstrate that the silicate antibacterial coating of the present invention has excellent antibacterial and hydrophobic properties.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use 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 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 disclosed herein.

Claims

1. A silicate antibacterial coating, characterized in that, The raw materials include the following parts by weight: 100 parts inorganic silicate, 1-30 parts antibacterial modifier, 10-100 parts silica sol, 1-10 parts dispersant, 0-30 parts thickener, 0-10 parts defoamer, 10-30 parts inorganic filler, 0-30 parts silicone-acrylic emulsion, and 1-100 parts water; The antibacterial modifier is an active silane antibacterial modifier with a side chain containing sulfonium ions, and its structural formula is as follows: , where m=0-3, n=0-18.

2. The silicate antibacterial coating according to claim 1, characterized in that, The raw materials include the following parts by weight: 100 parts inorganic silicate, 30 parts antibacterial modifier, 10 parts silica sol, 5 parts dispersant, 20 parts thickener, 2 parts defoamer, 10 parts inorganic filler, 5 parts silicone acrylic emulsion, and 30 parts water.

3. A silicate antibacterial coating according to claim 1 or 2, characterized in that, The inorganic silicate is potassium silicate.

4. A silicate antibacterial coating according to claim 1 or 2, characterized in that, The method for preparing the antibacterial modifier is as follows: (1) Vinylalkoxysilane and ethanethiol were dissolved in tetrahydrofuran and subjected to ultraviolet catalysis under nitrogen protection to obtain (2-(ethylthio)ethyl)trialkoxysilane; (2) Dissolve (2-(ethio)ethyl)trialkoxysilane and fluorinated iodoalkane in tetrahydrofuran, add an alkaline catalyst, and react overnight to obtain an antibacterial modifier.

5. The silicate antibacterial coating according to claim 4, characterized in that, In step (1), the mass ratio of vinylalkoxysilane, ethanethiol and tetrahydrofuran is 1.1g:1.2g:20mL; the ultraviolet light wavelength of the ultraviolet catalysis is 365nm and the time is 2h.

6. The silicate antibacterial coating according to claim 4, characterized in that, In step (2), the fluorinated iodoalkane is 1,1,1,2,2-pentafluoro-3-iodopropane; the base catalyst is triethylamine; and the mass ratio of (2-(ethylthio)ethyl)trialkoxysilane, fluorinated iodoalkane, tetrahydrofuran and base catalyst is 1g:2g:20mL:0.2mL.

7. A silicate antibacterial coating according to claim 1 or 2, characterized in that, The dispersant is at least one of acrylic acid copolymer, sodium phosphate, potassium phosphate, sodium carboxylate, and potassium carboxylate; the thickener is at least one of alumina, bentonite, aluminum silicate, carboxymethyl cellulose, chitosan, and sodium alginate.

8. A silicate antibacterial coating according to claim 1 or 2, characterized in that, The defoamer is at least one of the following: organosilicon oil, aminosulfate, glycine, sodium silicate, magnesium silicate, aluminum hydroxide, magnesia, and zinc oxide; the inorganic filler is at least one of the following: kaolin, talc, silica lime, mica, clay, and asbestos.

9. A method for preparing a silicate antibacterial coating, characterized in that, Specifically, the following steps are included: (1) Weigh each raw material according to the weight parts of the silicate antibacterial coating according to any one of claims 1-8; (2) Mix the inorganic silicate, antibacterial modifier, silica sol, dispersant, thickener, defoamer, inorganic filler and silicone-acrylic emulsion evenly to obtain a mixture; (3) Add water to the mixture and stir well to obtain a slurry; (4) Grind and filter the slurry to obtain the silicate antibacterial coating.

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