A water-based ceramic tile coating and method of preparation and use in the renovation of existing buildings

Abstract

The application belongs to the technical field of epoxy resin paint, and discloses a water-based ceramic tile paint, a preparation method and application in old house renovation. Water-based epoxy resin, modified titanium dioxide, water-based color paste, defoaming agent and leveling agent are added into a dispersing machine, dispersed, and finally a curing agent is added and stirred to prepare the water-based ceramic tile paint. Carboxyl groups are introduced on the surface of nano titanium dioxide, which reacts with epoxy groups of the epoxy resin in the heat curing process, has better toughening and reinforcing effect, and improves the flexibility, impact resistance and antibacterial performance of the paint film. The water-based epoxy resin does not contain organic solvents, is non-toxic and non-polluting, can directly cover the original floor and wall tiles by spraying and brushing, and is suitable for humid places such as kitchens and bathrooms where bacteria and mold are easy to breed.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin coating technology, specifically a water-based ceramic tile coating and its preparation method, as well as its application in old house renovation. Background Technology

[0002] Epoxy resin coatings possess high mechanical strength, good water resistance, and strong corrosion resistance, making them widely used in tile coatings, building exterior wall coatings, and floor paints. However, epoxy resins have poor flexibility, are prone to cracking, and ordinary epoxy resin coatings lack antibacterial properties, making them susceptible to bacterial and mold growth, which hinders their practical application in kitchen and bathroom coatings.

[0003] Nano-titanium dioxide possesses excellent strength, antibacterial properties, and UV resistance. When added to coatings, it can impart good toughness, strength, antibacterial, and antifungal properties. However, nano-titanium dioxide is prone to agglomeration, resulting in poor dispersibility in epoxy resin coatings. Dispersion modification of nano-titanium dioxide is usually required, using agents such as silane coupling agents, titanate coupling agents, and sodium stearate. However, these dispersants are typically oil-soluble and not water-soluble, meaning that even dispersion-modified titanium dioxide still suffers from poor dispersibility in water-based epoxy resins. Summary of the Invention

[0004] (I) Technical problem to be solved: In view of the shortcomings of the existing technology, the present invention provides a water-based ceramic tile coating and its preparation method and its application in old house renovation, which solves the problem of poor toughness and antibacterial properties of epoxy resin coatings.

[0005] (II) To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing water-based ceramic tile coating: (1) Add N,N-dimethylacetamide, pyromellitic anhydride and KH550 to the flask and react. Remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize and purify in dichloromethane to obtain ethoxysilane dispersant.

[0006] (2) Add ethanol, water and ethoxysilane dispersant to the flask, add acetic acid dropwise, stir and then add nano titanium dioxide, ultrasonically disperse and stir to modify, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0007] (3) Add water-based epoxy resin, modified titanium dioxide, water-based color paste, defoamer and leveling agent to the disperser, disperse, and finally add curing agent and stir to obtain water-based ceramic tile coating.

[0008] Preferably, the ratio of pyromellitic anhydride and KH550 in (1) is 1 mol: (2-2.1) mol.

[0009] Preferably, in (1), the reaction is stirred at room temperature for 4-5 hours.

[0010] Preferably, the ratio of ethoxysilane dispersant and nano titanium dioxide in (2) is (10-50) mmol:100g.

[0011] Preferably, the particle size of nano-titanium dioxide in (2) is 20-400 nm.

[0012] Preferably, in (2), acetic acid is added dropwise to adjust the pH to 3-5.

[0013] Preferably, the stirring modification in (2) is carried out at 60-80℃ for 2-4 hours.

[0014] Preferably, in (3), the ratio of waterborne epoxy resin, modified titanium dioxide, waterborne pigment, defoamer, leveling agent and curing agent is 100g: (1-2.5)g: (2-7)g: (0.6-1)g: (0.3-0.6)g: (28-33)g.

[0015] Preferably, the dispersion in (3) is carried out at room temperature for 0.5-1h.

[0016] Preferably, water-based ceramic tile coatings are used in the renovation of old houses.

[0017] (III) Beneficial technical effects: The ethoxysilane dispersant of the present invention contains multiple ethoxysilane groups, which have a higher reaction rate with the hydroxyl groups on the surface of nano titanium dioxide, resulting in better surface modification. The nano titanium dioxide is not easy to agglomerate. The modified titanium dioxide also introduces hydrophilic carboxyl groups, amide bonds, etc., which significantly improves the dispersibility of titanium dioxide in waterborne epoxy resin coatings. There are no sediments in the coating, and the stability is very good.

[0018] The titanium dioxide surface of this invention incorporates carboxyl groups, which react with the epoxy groups of the epoxy resin during thermosetting, forming covalent bonds between the titanium dioxide and epoxy resin. This enhances the bonding strength between the titanium dioxide and epoxy resin, resulting in better toughening and reinforcement, and improving the flexibility and impact resistance of the paint film. Simultaneously, the nano-titanium dioxide is uniformly dispersed in the coating and paint film, possessing higher photocatalytic active sites, significantly improving the antibacterial zone width and antibacterial properties of the paint film. This water-based epoxy resin is solvent-free, non-toxic, and pollution-free, and can be directly applied to existing floor and wall tiles via spraying or brushing, making it suitable for damp and mold-prone areas such as kitchens and bathrooms. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0020] The following waterborne epoxy resin, brand name XG150, with a solid content of approximately 50%, is sourced from Shanghai Xiaogen New Material Technology Co., Ltd. The curing agent, brand name WH-900, is a modified polyamine-based waterborne curing agent sourced from Wuhan Huaxiang Kejie Biotechnology Co., Ltd. The nano-titanium dioxide has an average particle size of 50nm. The waterborne colorant, brand name Da Hong Waterborne Colorant 2001, with a solid content of approximately 38%, is sourced from Handan Tengke Chemical Distribution Co., Ltd.

[0021] Example 1: (1) Add 12 mL of N,N-dimethylacetamide, 5 mmol of pyromellitic anhydride, and 10 mmol of KH550 to a flask, stir at room temperature for 4 h, remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize in dichloromethane to obtain ethoxysilane dispersant. The preparation reaction formula is as follows: .

[0022] (2) Add 400 mL of ethanol, 40 mL of water and 3 mmol of ethoxysilane dispersant to the flask, add glacial acetic acid to adjust the pH to 3, stir and add 10 g of nano titanium dioxide, sonicate for 20 min, heat to 70 °C, stir and modify for 2 h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0023] (3) Add 1kg of waterborne epoxy resin, 10g of modified titanium dioxide, 40g of waterborne pigment, 6g of defoamer TEGO ANTIFOAM 3062, and 5g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 0.5h, and finally add 330g of curing agent and stir to obtain waterborne ceramic tile coating.

[0024] Example 2: (1) Add 10 mL of N,N-dimethylacetamide, 3 mol of pyromellitic anhydride and 6.3 mol of KH550 to the flask, stir the reaction at room temperature for 5 h, remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize and purify in dichloromethane to obtain ethoxysilane dispersant.

[0025] (2) Add 800 mL of ethanol, 100 mL of water and 2 mmol of ethoxysilane dispersant to the flask, add glacial acetic acid to adjust the pH to 5, stir and add 20 g of nano titanium dioxide, sonicate for 30 min, heat to 80 °C, stir and modify for 2 h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0026] (3) Add 1kg of waterborne epoxy resin, 20g of modified titanium dioxide, 70g of waterborne pigment, 7g of defoamer TEGO ANTIFOAM 3062, and 6g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 1h, and finally add 300g of curing agent and stir to obtain waterborne ceramic tile coating.

[0027] Example 3: (1) Add 40 mL of N,N-dimethylacetamide, 15 mmol of pyromellitic anhydride and 31.5 mmol of KH550 to the flask, stir the reaction at room temperature for 4 h, remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize and purify in dichloromethane to obtain ethoxysilane dispersant.

[0028] (2) Add 1L of ethanol, 120mL of water and 12.5mmol of ethoxysilane dispersant to the flask, add glacial acetic acid to adjust the pH to 3, stir and add 25g of nano titanium dioxide, sonicate for 30min, heat to 60℃, stir and modify for 4h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0029] (3) Add 1kg of waterborne epoxy resin, 25g of modified titanium dioxide, 20g of waterborne pigment, 10g of defoamer TEGO ANTIFOAM 3062, and 3g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 1h, and finally add 280g of curing agent and stir to obtain waterborne ceramic tile coating.

[0030] Comparative Example 1 differs from Example 1 in that unmodified nano-titanium dioxide was added.

[0031] (1) Add 1kg of waterborne epoxy resin, 10g of nano titanium dioxide, 40g of waterborne pigment, 6g of defoamer TEGO ANTIFOAM 3062, and 5g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 0.5h, and finally add 330g of curing agent and stir to obtain waterborne ceramic tile coating.

[0032] Comparative Example 2 differs from Example 1 in that KH550 is used instead of ethoxysilane dispersant.

[0033] (1) Add 400 mL of ethanol, 40 mL of water and 3 mmol of KH550 to the flask, add glacial acetic acid to adjust the pH to 3, stir and add 10 g of nano titanium dioxide, sonicate for 20 min, heat to 70 °C, stir and modify for 2 h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0034] (2) Add 1kg of waterborne epoxy resin, 10g of modified titanium dioxide, 40g of waterborne pigment, 6g of defoamer TEGO ANTIFOAM 3062, and 5g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 0.5h, and finally add 330g of curing agent and stir to obtain waterborne ceramic tile coating.

[0035] Comparative Example 3 differs from Example 1 in that n-butylamine is used instead of KH550.

[0036] (1) Add 12 mL of N,N-dimethylacetamide, 5 mmol of pyromellitic anhydride, and 10 mmol of n-butylamine to a flask, stir at room temperature for 4 h, remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize in dichloromethane to obtain a dispersant with the following structural formula: .

[0037] (2) Add 400 mL of ethanol, 40 mL of water and 3 mmol of dispersant to the flask, add glacial acetic acid to adjust the pH to 3, stir and add 10 g of nano titanium dioxide, sonicate for 20 min, heat to 70 °C, stir and modify for 2 h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0038] (3) Add 1kg of waterborne epoxy resin, 10g of modified titanium dioxide, 40g of waterborne pigment, 6g of defoamer TEGO ANTIFOAM 3062, and 5g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 0.5h, and finally add 330g of curing agent and stir to obtain waterborne ceramic tile coating.

[0039] Comparative Example 4 differs from Example 1 in that phthalic anhydride is used instead of pyromellitic anhydride.

[0040] (1) Add 12 mL of N,N-dimethylacetamide, 5 mmol of phthalic anhydride, and 5 mmol of KH550 to a flask, stir at room temperature for 4 h, remove N,N-dimethylacetamide by vacuum distillation, wash the product with n-hexane, and then recrystallize in dichloromethane to obtain an ethoxysilane dispersant with the following structural formula: .

[0041] (2) Add 400 mL of ethanol, 40 mL of water and 3 mmol of ethoxysilane dispersant to the flask, add glacial acetic acid to adjust the pH to 3, stir and add 10 g of nano titanium dioxide, sonicate for 20 min, heat to 70 °C, stir and modify for 2 h, filter and wash the precipitate with water and ethanol, dry and grind to obtain modified titanium dioxide.

[0042] (3) Add 1kg of waterborne epoxy resin, 10g of modified titanium dioxide, 40g of waterborne pigment, 6g of defoamer TEGO ANTIFOAM 3062, and 5g of leveling agent Dow Corning DC57 to the disperser, disperse at room temperature for 0.5h, and finally add 330g of curing agent and stir to obtain waterborne ceramic tile coating.

[0043] The water-based ceramic tile coatings (without water-based colorant) of each example were placed at room temperature for 30 days to observe the stability of the coatings.

[0044] The coating is cured at 100℃ for 2 hours and 130℃ for 2 hours to form a film. Flexibility is tested according to GB / T 1731-2020 standard. Impact resistance is tested according to GB / T 1732-2020 standard.

[0045] Antibacterial performance test of the coating film: 1 mL of activated bacterial solution (Escherichia coli or Staphylococcus aureus, concentration approximately 1 × 10⁻⁶) was inoculated into 150 mL of agar medium heated to 45 °C. 8 (CFU / mL), shake to mix, solidify at room temperature to prepare inoculation medium. Add ordinary agar medium to the petri dish, then press and adhere a circular paint film sample on top of the agar medium, then add inoculation medium on top of the paint film sample, press and adhere, and incubate at 37℃ for 24h. Measure the width H of the inhibition zone, H = (Dd) / 2, where D is the outer diameter of the inhibition zone and d is the diameter of the paint film sample.

[0046] Table 1 Performance Tests

[0047] Testing revealed that the nano-titanium dioxide in each embodiment, after modification with an ethoxysilane dispersant, introduced hydrophilic carboxyl groups and amide bonds, significantly improving its dispersibility in aqueous epoxy resin solutions. This resulted in less agglomeration, no sedimentation in the coating, and excellent stability. Furthermore, the introduced carboxyl groups on the titanium dioxide surface reacted with the epoxy groups of the epoxy resin during thermosetting, forming covalent bonds between the titanium dioxide and epoxy resin. This enhanced the bonding strength between the titanium dioxide and epoxy resin, providing better toughening and reinforcement, and improving the flexibility and impact resistance of the paint film. Simultaneously, the uniform dispersion of nano-titanium dioxide in the coating and film resulted in higher photocatalytic active sites, effectively improving the antibacterial zone width and antibacterial properties of the paint film.

[0048] The nano-titanium dioxide in Comparative Example 1 exhibits poor dispersibility in waterborne epoxy resin, tends to agglomerate, and easily produces titanium dioxide sediment in the coating. Furthermore, its low bonding strength with epoxy resin results in low flexibility and impact resistance of the paint film, as well as poor antibacterial properties.

[0049] Comparative Example 2 uses conventional KH550 to modify nano-titanium dioxide. However, it has a low ethoxysilane content, resulting in poor modification effect on nano-titanium dioxide. Furthermore, it does not contain hydrophilic carboxyl groups, leading to poor dispersibility of the modified titanium dioxide in waterborne epoxy resin. This causes it to aggregate and produce sediment, resulting in poor flexibility, impact resistance, and antibacterial properties of the paint film.

[0050] The dispersant in Comparative Example 3 does not contain ethoxysilane, resulting in poor modification of nano-titanium dioxide. Titanium dioxide exhibits poor dispersibility in waterborne epoxy resin, easily agglomerating and producing sediments, which affects the stability of the coating. Furthermore, the coating film exhibits poor flexibility, impact resistance, and antibacterial properties.

[0051] The ethoxysilane dispersant in Comparative Example 4 has a low ethoxysilane content, resulting in poor modification effect on nano-titanium dioxide. It also has a low carboxyl content, leading to poor dispersibility of modified titanium dioxide in waterborne epoxy resin. It will aggregate and produce sediment, and the curing effect with epoxy resin is also low, resulting in poor flexibility, impact resistance and antibacterial properties of the paint film.

Claims

1. A method for preparing a water-based ceramic tile coating, characterized in that, The preparation method includes: S1. Add ethanol, water, and ethoxysilane dispersant to a flask, add acetic acid dropwise, stir, add nano titanium dioxide, ultrasonically disperse, stir to modify, filter, wash the precipitate, dry, grind, and obtain modified titanium dioxide. The structural formula of the ethoxysilane dispersant is: ; S2. Add water-based epoxy resin, modified titanium dioxide, water-based color paste, defoamer, and leveling agent to the disperser, disperse them, and finally add curing agent and stir to obtain water-based ceramic tile coating.

2. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The ratio of ethoxysilane dispersant to nano-titanium dioxide in S1 is (10-50) mmol:100g.

3. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The particle size of the nano-titanium dioxide in S1 is 20-400 nm.

4. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, Acetic acid is added dropwise to S1 to adjust the pH to 3-5.

5. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The stirring modification in S1 is carried out at 60-80℃ for 2-4 hours.

6. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The ratio of waterborne epoxy resin, modified titanium dioxide, waterborne pigment, defoamer, leveling agent and curing agent in S2 is 100g:(1-2.5)g:(2-7)g:(0.6-1)g:(0.3-0.6)g:(28-33)g.

7. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The dispersion in S2 is carried out at room temperature for 0.5-1 h.

8. The method for preparing water-based ceramic tile coating according to claim 1, characterized in that, The preparation method of the ethoxysilane dispersant in S2 is as follows: N,N-dimethylacetamide, pyromellitic anhydride in a ratio of 1 mol: (2-2.1) mol, and KH550 are added to a flask, the mixture is stirred at room temperature for 4-5 h, N,N-dimethylacetamide is removed by vacuum distillation, the product is washed, and then recrystallized and purified to obtain the ethoxysilane dispersant.

9. A water-based ceramic tile coating prepared by the preparation method according to any one of claims 1-8.

10. The application of the water-based ceramic tile coating as described in claim 9 in the renovation of old houses.

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