Highly efficient flame-retardant self-healing coating and preparation method thereof

Abstract

The application provides a high-efficiency flame-retardant self-repairing coating and a preparation method thereof. The method comprises the following steps: mixing and stirring 100 parts of a water-based copolymer, 10-15 parts of a terpolymer, 5-10 parts of low-melting-point glass powder and 3-8 parts of modified boron nitride nanosheet, adding 2-3 parts of a defoaming agent, and obtaining the high-efficiency flame-retardant self-repairing coating after stirring. The terpolymer is added to form strong adhesion to the base material. Meanwhile, extensive hydrogen bonds and other non-covalent interactions are formed between the terpolymer chains. The self-repairing coating can rapidly self-repair at room temperature through a series of dynamic non-covalent interactions. The self-repairing property enables the surface coating to spontaneously restore its protective function after damage and to play its function in an easily-damaged external environment. In addition, the coating can quickly form a dense and structurally complete carbon layer when encountering fire, can dilute combustible gas, and can inhibit chain reactions by releasing phosphorus-containing free radicals to quench active free radicals in the gas phase, thereby greatly improving the flame retardancy of the material.

Description

Technical Field

[0001] This invention relates to the field of coatings, specifically to a high-efficiency flame-retardant self-healing coating and its preparation method. Background Technology

[0002] Water-based coatings use water instead of organic solvents as the dispersion. Compared to traditional oil-based coatings, they offer advantages such as low organic compound emissions, environmental friendliness, and safety. Furthermore, water-based coatings boast superior and controllable mechanical properties, low-temperature resistance, and good compatibility, making them widely applicable in architectural coatings. With the development of the architectural coatings market, coatings with specific functions are increasingly favored. Currently, most water-based coatings on the market lack flame retardant properties or have poor flame retardancy, significantly reducing their practicality and applicability in the construction industry. The current market primarily uses flame retardants to improve the flame retardant performance of water-based coatings, generally involving large quantities and often resulting in poor compatibility, which affects the mechanical properties, toughness, and mechanical strength of the coatings. In addition, water-based architectural coatings are prone to scratches during long-term use, causing damage to the appearance and significantly reducing the coating's protective capabilities. Therefore, the lack of self-healing ability for micro-cracks is a significant shortcoming of most water-based architectural coatings currently on the market. Therefore, the research and development of coatings with high flame retardancy and self-healing properties is of great significance to the development of the construction industry. Summary of the Invention

[0003] Technical Problem to be Solved: This invention addresses the aforementioned technical problems by proposing a highly efficient flame-retardant self-healing coating and its preparation method. This invention incorporates a terpolymer, composed of hydroxyethyl acrylate, vinylphosphonic acid, and dopamine methacrylate. Through the interaction between the benzene ring and catechol groups, a strong adhesion to the substrate is formed. Simultaneously, extensive hydrogen bonds and other non-covalent interactions are formed between the terpolymer chains. Through a series of dynamic non-covalent interactions, it can rapidly self-heal at room temperature. This self-healing property allows the surface coating to spontaneously recover its protective function after damage and function effectively in vulnerable external environments. Furthermore, upon exposure to fire, it can rapidly form a dense, structurally complete carbon layer, dilute flammable gases, and inhibit chain reactions by releasing phosphorus-containing free radicals to quench active free radicals in the gas phase, significantly improving the material's flame retardancy.

[0004] Technical solution: A high-efficiency flame-retardant self-healing coating, comprising the following components by weight: water-based copolymer, terpolymer, low-melting-point glass powder, and modified boron nitride nanosheets;

[0005] The terpolymer is a copolymer of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate.

[0006] Furthermore, the aqueous copolymer includes aqueous polyurethane resin, aqueous acrylic resin, and aqueous epoxy resin.

[0007] Furthermore, the softening temperature of the low-melting-point glass powder is 350°C, and the melting point is 500°C.

[0008] Furthermore, the preparation method of the terpolymer is as follows:

[0009] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 30-50 min to obtain terpolymer solution;

[0010] (2) Remove the solvent from the terpolymer solution and spray dry to obtain the terpolymer.

[0011] Furthermore, the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid, and dopamine methacrylate is 45:(49-51):(4-6). Furthermore, the preparation method of the modified boron nitride nanosheets is as follows:

[0012] Step 1: Disperse 0.5g boron nitride nanosheets in 200mL tannic acid aqueous solution, stir at 300rpm for 20min, and then sonicate at 100W for 30min;

[0013] Step 2: Add PBS buffer, adjust the pH to 7.4, add 0.5 mL of ferric chloride aqueous solution and stir for 45 s;

[0014] Step 3: Centrifuge at 3000 rpm for 8 min, filter, wash, and dry the filter cake to obtain modified boron nitride nanosheets. Further, the concentration of the tannic acid aqueous solution is 0.2 mg / mL; the concentration of the ferric chloride aqueous solution is 6 mg / mL. The preparation method of the above-mentioned high-efficiency flame-retardant self-healing coating includes the following steps: take 100 parts of aqueous copolymer, 10-15 parts of terpolymer, 5-10 parts of low-melting-point glass powder, and 3-8 parts of modified boron nitride nanosheets, mix and stir, add 2-3 parts of defoamer, and stir for 40 min to obtain the high-efficiency flame-retardant self-healing coating.

[0015] Beneficial effects:

[0016] 1. This invention incorporates a terpolymer composed of hydroxyethyl acrylate, vinylphosphonic acid, and dopamine methacrylate. Through the interaction between the benzene ring and catechol groups, it forms a strong adhesion to the substrate. Simultaneously, extensive hydrogen bonds and other non-covalent interactions are formed between the terpolymer chains. Through a series of dynamic non-covalent interactions, it can rapidly self-heal at room temperature. This self-healing property allows the surface coating to spontaneously recover its protective function after damage and maintain its functionality in vulnerable external environments. Furthermore, upon exposure to fire, it can rapidly form a dense, structurally complete carbon layer, dilute flammable gases, and inhibit chain reactions by releasing phosphorus-containing free radicals to quench active free radicals in the gas phase, significantly improving the flame retardancy of the material.

[0017] 2. The low-melting-point glass powder added in this invention softens when the temperature is above 350°C and eventually melts completely at 650°C to form a flowing melt. This melt acts as a high-temperature adhesive to fill macroscopic cracks on the surface of the carbon layer formed by the terpolymer and ultimately forms a dense and complete ceramic protective layer, improving flame retardancy.

[0018] 3. In this invention, the modified boron nitride nanosheets can synergistically improve the flame retardancy of low-melting-point glass powder. At the same time, the modified surface coating contains phenolic hydroxyl groups that can undergo ring-opening reactions with epoxy groups, resulting in better interfacial compatibility with the substrate. Detailed Implementation

[0019] Example 1

[0020] The preparation method of modified boron nitride nanosheets is as follows:

[0021] Step 1: Disperse 0.5g boron nitride nanosheets in 200mL of tannic acid aqueous solution with a concentration of 0.2mg / mL, stir at 300rpm for 20min, and then sonicate at 100W for 30min.

[0022] Step 2: Add PBS buffer, adjust the pH to 7.4, add 0.5 mL of 6 mg / mL ferric chloride aqueous solution and stir for 45 s;

[0023] Step 3: Centrifuge at 3000 rpm for 8 min, filter, wash, and dry the filter cake to obtain modified boron nitride nanosheets.

[0024] Example 2

[0025] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 10 parts of terpolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0026] The preparation method of the terpolymer is as follows:

[0027] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0028] Example 3

[0029] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0030] The preparation method of the terpolymer is as follows:

[0031] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0032] Example 4

[0033] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 15 parts of terpolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0034] The preparation method of the terpolymer is as follows:

[0035] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0036] Example 5

[0037] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 5 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0038] The preparation method of the terpolymer is as follows:

[0039] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0040] Example 6

[0041] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 10 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0042] The preparation method of the terpolymer is as follows:

[0043] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0044] Example 7

[0045] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 8 parts of low-melting-point glass powder, and 3 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0046] The preparation method of the terpolymer is as follows:

[0047] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0048] Example 8

[0049] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 8 parts of low-melting-point glass powder, and 8 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0050] The preparation method of the terpolymer is as follows:

[0051] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0052] Example 9

[0053] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0054] The preparation method of the terpolymer is as follows:

[0055] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:49:6; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0056] Example 10

[0057] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0058] The preparation method of the terpolymer is as follows:

[0059] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:51:4; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0060] Comparative Example 1

[0061] The difference between this embodiment and Embodiment 3 is that no terpolymer is added, as detailed below:

[0062] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred, 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and the melting point is 500℃.

[0063] Comparative Example 2

[0064] The difference between this embodiment and Embodiment 3 is that low-melting-point glass powder is not added, as detailed below:

[0065] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: taking 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, and 6 parts of modified boron nitride nanosheets, mixing and stirring, adding 3 parts of defoamer, and stirring for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating.

[0066] The preparation method of the terpolymer is as follows:

[0067] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0068] Comparative Example 3

[0069] The difference between this embodiment and Example 3 is that modified boron nitride nanosheets are not added, as detailed below:

[0070] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of terpolymer, and 8 parts of low-melting-point glass powder are mixed and stirred; 3 parts of defoamer are added; and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0071] The preparation method of the terpolymer is as follows:

[0072] (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain terpolymer solution; the molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:50:5; (2) Remove the solvent in the terpolymer solution and spray dry to obtain terpolymer.

[0073] Comparative Example 4

[0074] The difference between this embodiment and Embodiment 3 is that the terpolymer is replaced with a binary copolymer, as detailed below:

[0075] A method for preparing a high-efficiency flame-retardant self-healing coating includes the following steps: 100 parts of waterborne polyurethane resin, 13 parts of a binary copolymer, 8 parts of low-melting-point glass powder, and 6 parts of modified boron nitride nanosheets are mixed and stirred. 3 parts of defoamer are added, and the mixture is stirred for 40 minutes to obtain the high-efficiency flame-retardant self-healing coating. The softening temperature of the low-melting-point glass powder is 350℃, and its melting point is 500℃.

[0076] The preparation method of the binary copolymer is as follows:

[0077] (1) Take hydroxyethyl acrylate and vinylphosphonic acid, add ethanol aqueous solution, stir and copolymerize for 40 min to obtain a binary copolymer solution; the molar ratio of hydroxyethyl acrylate and vinylphosphonic acid is 45:50;

[0078] (2) Remove the solvent from the binary copolymer solution and spray dry to obtain the binary copolymer.

[0079] The high-efficiency flame-retardant self-healing coating prepared in the above embodiments was applied to the treated wood board, and after UV curing, a coating with a thickness of 200 μm was formed. The substrate adhesion (shear strength) and flame-retardant performance were tested, and the results are shown in Table 1 below:

[0080] Table 1

[0081]

[0082]

Claims

1. A high-efficiency flame-retardant self-healing coating, characterized in that, By weight, it includes the following components: aqueous copolymer, terpolymer, low melting point glass powder, and modified boron nitride nanosheets; The terpolymer is a copolymer of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate. The waterborne copolymer includes waterborne polyurethane resin, waterborne acrylic resin, and waterborne epoxy resin; The method for preparing the modified boron nitride nanosheets is as follows: Step 1: Disperse 0.5g boron nitride nanosheets in 200 mL of tannic acid aqueous solution, stir at 300 rpm for 20 min, and then sonicate at 100 W for 30 min; Step 2: Add PBS buffer, adjust the pH to 7.4, add 0.5 mL of ferric chloride aqueous solution and stir for 45 s; Step 3: Centrifuge at 3000 rpm for 8 min, filter, wash, and dry the filter cake to obtain modified boron nitride nanosheets.

2. The high-efficiency flame-retardant self-healing coating according to claim 1, characterized in that: The softening temperature of the low-melting-point glass powder is 350℃, and the melting point is 500℃.

3. The high-efficiency flame-retardant self-healing coating according to claim 1, characterized in that: The preparation method of the terpolymer is as follows: (1) Take hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate, add ethanol aqueous solution, stir and copolymerize for 30-50 min to obtain terpolymer solution; (2) Remove the solvent from the terpolymer solution and spray dry to obtain the terpolymer.

4. The high-efficiency flame-retardant self-healing coating according to claim 3, characterized in that: The molar ratio of hydroxyethyl acrylate, vinylphosphonic acid and dopamine methacrylate is 45:(49-51):(4-6).

5. The high-efficiency flame-retardant self-healing coating according to claim 1, characterized in that: The concentration of the tannic acid aqueous solution is 0.2 mg / mL; the concentration of the ferric chloride aqueous solution is 6 mg / mL.

6. A method for preparing a high-efficiency flame-retardant self-healing coating according to any one of claims 1-5, characterized in that: Includes the following steps: Take 100 parts of water-based copolymer, 10-15 parts of terpolymer, 5-10 parts of low-melting-point glass powder, and 3-8 parts of modified boron nitride nanosheets, mix and stir, add 2-3 parts of defoamer, and stir for 40 minutes to obtain a high-efficiency flame-retardant self-healing coating.

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