Water-based calcium silicate board coating with super-hydrophobic, efficient insulating and flame-retardant properties and preparation method of water-based calcium silicate board coating

Abstract

The invention discloses a water-based calcium silicate board coating with super-hydrophobic, efficient insulating and flame-retardant properties and a preparation method of the water-based calcium silicate board coating, and relates to the field of coatings. The water-based calcium silicate board coating is prepared from 2-4 wt% of a water-based organic silicon impregnated water repellent, 28-35 wt% of water-based epoxy resin, 4-6 wt% of amino resin, 3-5 wt% of a coalescing agent, 0.4-0.6 wt% of a water-based wetting agent and the balance of a diluent. The water-based calcium silicate board coating has excellent flame retardant property, hydrophobic property and insulating property, is suitable for dip-coating construction of a calcium silicate board, can obtain a paint film with the thickness of less than or equal to 15 microns, does not have the problems of orange peel, sagging, tear stains and the like, has a decorative effect, and has the advantages of high drying speed, coating saving and cost reduction.

Description

Technical Field

[0001] This application relates to the field of coatings, and in particular to a waterborne calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties and its preparation method. Background Technology

[0002] Calcium silicate board (also known as calcium silicate board) is a new type of building material made primarily from siliceous materials (such as quartz sand), calcareous materials (such as lime and cement), and reinforcing fibers, through processes such as pulping, molding, and autoclaving. Calcium silicate board boasts A1-level flame retardancy, does not release toxic fumes, has a maximum fire resistance limit of 240 minutes, and is lightweight, moisture-proof, corrosion-resistant, heat-insulating, and sound-insulating, with a thermal conductivity of <0.065W / m▪K. It is also environmentally friendly and asbestos-free. Currently, calcium silicate board can replace aluminum boards, for example, in applications requiring insulation and moisture resistance, such as in new energy vehicles and the power industry.

[0003] Compared to aluminum ceiling panels, calcium silicate boards offer superior bioactivity and comparable moisture resistance, but their decorative properties are slightly inferior. Currently, calcium silicate boards require painting to improve their appearance; however, this painting process must not reduce their flame retardant, hydrophobic, or insulating properties. Furthermore, considering ease of application, dip coating offers superior convenience. Summary of the Invention

[0004] In order to obtain a coating that has excellent flame retardant, hydrophobic and insulating properties and is suitable for dip coating of calcium silicate boards, this application provides a water-based calcium silicate board coating with super hydrophobic, high-efficiency insulating and flame retardant properties and its preparation method.

[0005] Firstly, the water-based calcium silicate board coating with superhydrophobic, highly efficient insulating, and flame-retardant properties provided in this application adopts the following technical solution: A water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties, wherein the water-based calcium silicate board coating is prepared by 2-4 wt% water-based organosilicon impregnation water-repellent agent, 28-35 wt% water-based epoxy resin, 4-6 wt% amino resin, 3-5 wt% film-forming aid, 0.4-0.6 wt% water-based wetting agent and the balance being diluent.

[0006] In this application, the waterborne calcium silicate board coating uses waterborne organosilicon impregnation water-repellent agent, waterborne epoxy resin, and amino resin as film-forming materials. The addition of an appropriate amount of waterborne organosilicon impregnation water-repellent agent significantly enhances the hydrophobic and flame-retardant effects of the coating film, resulting in a water droplet angle ≥115°C and a flame-retardant rating of A2. However, it is important to note that the waterborne organosilicon impregnation water-repellent agent should not be added excessively, as excessive addition will make it difficult to achieve proper drying under the same baking conditions. Furthermore, this application enhances the cross-linking density of the coating film through the synergistic effect of waterborne epoxy resin and amino resin, thereby increasing the film hardness, improving its scratch resistance, and achieving a resistivity of over 500 megohms, effectively improving the film's insulation performance.

[0007] The film-forming aids and water-based wetting agents, when combined with water-based organosilicon impregnation water-repellent agent, water-based epoxy resin, amino resin and diluent in a specific ratio according to this application, can obtain a water-based calcium silicate board coating with low viscosity and good penetration into calcium silicate boards, suitable for dip coating construction. When using this water-based calcium silicate board coating for dip coating construction of calcium silicate boards, the film thickness is ≤15μm, and problems such as orange peel, sagging, and tear marks will not occur. It can not only achieve a decorative effect, but also has the advantages of fast drying speed, saving paint and reducing costs.

[0008] In some specific embodiments, the waterborne epoxy resin is an inorganically modified waterborne epoxy resin, and the preparation method of the inorganically modified waterborne epoxy resin is as follows: Prepare a silicate aqueous solution with a mass concentration of 4-6% by using 2.5-3 parts by weight of silicate powder; While stirring, dilute acid solution is added dropwise to silicate aqueous solution at 0-4℃ to adjust the pH of the system to 3-4, and then the system is allowed to stand at 25-30℃ for 6-12 hours to obtain polysilicic acid sol. Prepare an aqueous solution of aminosilane coupling agent by mixing 1-1.5 parts by weight of aminosilane coupling agent with 25 parts by weight of water, adjust the pH to 4.5-5.0, hydrolyze at 40-50℃ for 0.5-1h, and then cool to room temperature to obtain aminosilane hydrolysate. While stirring, add aminosilane hydrolysate to the polysilicic acid sol and stir for 2-3 hours. Then add 100 parts by weight of waterborne epoxy resin, stir evenly, adjust the pH to 8-8.5, and stir evenly to obtain inorganic modified waterborne epoxy resin.

[0009] In this application, the inorganic modified waterborne epoxy resin uses silicate, which has flame-retardant properties, as the silicon source. Under acidic conditions, the silicate is induced to condense and form nanoscale polysilicic acid sol. Then, the silanol groups generated after the hydrolysis of the aminosilane coupling agent are used to bridge the reaction with the silanol groups on the polysilicic acid sol. Meanwhile, the amino groups on the aminosilane coupling agent are used to bridge the reaction with the epoxy groups in the waterborne epoxy resin, so that the polysilicic acid sol and the waterborne epoxy resin form a stable inorganic modified waterborne epoxy resin.

[0010] Compared with ordinary waterborne epoxy resins, the inorganic modified waterborne epoxy resin in this application can take into account both film-forming properties and flame retardant properties due to the modification of silicates. Through the synergistic effect of waterborne organosilicon impregnation water-repellent agent and inorganic modified waterborne epoxy resin, the flame retardant properties of waterborne calcium silicate board coating can be effectively improved, so that the flame retardant properties of the coating film reach A1 level.

[0011] In addition, the inorganic modified waterborne epoxy resin prepared by the specific method of this application can also be combined with waterborne organosilicon impregnation water-repellent agent, amino resin, film-forming aid, waterborne wetting agent and diluent to obtain a waterborne calcium silicate board coating that can be applied to calcium silicate boards by dip coating, with a film thickness of ≤15μm, and will not have problems such as orange peel, sagging, tear marks.

[0012] In some specific embodiments, the dilute acid solution is a dilute hydrochloric acid solution with a molar concentration of 1-1.5 mol / L.

[0013] In some specific embodiments, the aminosilane coupling agent is a primary aminosilane coupling agent.

[0014] Using primary aminosilane coupling agents is beneficial for improving the stability of inorganic modified waterborne epoxy resins.

[0015] In some specific embodiments, the silicate is at least one of sodium silicate and potassium silicate.

[0016] In some specific embodiments, the water-based organosilicon impregnation water-repellent agent is the water-based organosilicon water-repellent agent RUCOSAN B-WB.

[0017] In this application, the water-based organosilicon impregnation water-repellent agent used is RUCOSAN B-WB water-based organosilicon water-repellent agent from Guangdong Jiafucheng Materials Technology Co., Ltd. This water-based organosilicon water-repellent agent is an emulsion based on silane and modified polysiloxane, which can produce a significant lotus leaf effect, has high water resistance, and has good compatibility with the inorganic modified water-based epoxy resin of this application. When combined with amino resin, film-forming aid, and water-based wetting agent in a specific ratio, water-based calcium silicate board coating can be prepared. A paint film without problems such as orange peel, sagging, and tear marks can be obtained through dip coating.

[0018] In some specific embodiments, the film-forming aid is at least one of dipropylene glycol methyl ether and propylene glycol methyl ether.

[0019] Secondly, the preparation method of the waterborne calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties provided in this application adopts the following technical solution: A method for preparing a water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties includes the following steps: After uniformly mixing the film-forming aid, water-based wetting agent, and diluent, add the water-based organosilicon impregnation water-repellent agent, water-based epoxy resin, and amino resin, and stir evenly to obtain the water-based calcium silicate board coating.

[0020] In summary, this application includes at least the following beneficial technical effects: (1) In this application, the waterborne calcium silicate board coating uses waterborne organosilicon impregnation water-repellent agent, waterborne epoxy resin and amino resin as film-forming materials. Among them, the addition of an appropriate amount of waterborne organosilicon impregnation water-repellent agent can significantly improve the hydrophobic effect and flame retardant effect of the coating film, so that the water droplet angle of the coating film is ≥115° and the flame retardant rating reaches A2 level. However, it should be noted that the waterborne organosilicon impregnation water-repellent agent should not be added in excess. If the amount is excessive, the coating film will be difficult to dry under the same baking conditions. In addition, this application improves the cross-linking density of the coating film through the synergistic effect of waterborne epoxy resin and amino resin, which can increase the hardness of the coating film, improve the scratch resistance of the coating film, and make the resistivity of the coating film reach more than 500 megohms, effectively improving the insulation performance of the coating film.

[0021] (2) The water-based organosilicon impregnation water-repellent agent, water-based epoxy resin, amino resin, film-forming aid, water-based wetting agent and diluent in a specific ratio of this application can obtain a water-based calcium silicate board coating with low viscosity and good permeability to calcium silicate board, which is suitable for dip coating construction. When calcium silicate board is dip coated with this water-based calcium silicate board coating, the film thickness is ≤15μm and there will be no problems such as orange peel, sagging, tear marks. It can not only achieve a decorative effect, but also has the advantages of fast drying speed, saving paint and reducing cost.

[0022] (3) Compared with ordinary waterborne epoxy resin, the inorganic modified waterborne epoxy resin in this application can take into account both film-forming performance and flame retardant performance due to the modification of silicate. Through the synergistic effect of waterborne organosilicon impregnation water-repellent agent and inorganic modified waterborne epoxy resin, the flame retardant performance of waterborne calcium silicate board coating can be effectively improved, so that the flame retardant performance of the coating film reaches A1 level.

[0023] (4) The inorganic modified waterborne epoxy resin prepared by the specific method of this application can also be combined with waterborne organosilicon impregnation water-repellent agent, amino resin, film-forming aid, waterborne wetting agent and diluent to obtain a waterborne calcium silicate board coating that can be applied to calcium silicate board by impregnation, with a film thickness of ≤15μm, and will not have problems such as orange peel, sagging, tear marks. Attached Figure Description

[0024] Figure 1 This is an application effect diagram of the water-based calcium silicate board coating that combines superhydrophobicity, high-efficiency insulation and flame retardant properties (the texture is the texture of the calcium silicate board itself). Detailed Implementation

[0025] The following section provides further explanation of this application in conjunction with specific experiments. Example

[0026]

Example 1

[0027] Among them, the water-based organosilicon impregnation water-repellent agent used is RUCOSAN B-WB water-based organosilicon water-repellent agent from Guangdong Jiafucheng Materials Technology Co., Ltd.; The waterborne epoxy resin used is EP-601 waterborne single-component epoxy emulsion from Guangzhou Jiafucheng Trading Co., Ltd. The amino resin used is CY-385 amino resin from Guangzhou Jiafucheng Trading Co., Ltd. The film-forming aid used is dipropylene glycol methyl ether; The water-based wetting agent used is Tego270, a product of Guangzhou Meihan Trading Co., Ltd.

[0028]

Example 2

[0029] Among them, the water-based organosilicon impregnation water-repellent agent used is RUCOSAN B-WB water-based organosilicon water-repellent agent from Guangdong Jiafucheng Materials Technology Co., Ltd.; The waterborne epoxy resin used is EP-601 waterborne single-component epoxy emulsion from Guangzhou Jiafucheng Trading Co., Ltd. The amino resin used is CY-385 amino resin from Guangzhou Jiafucheng Trading Co., Ltd. The film-forming aid used is dipropylene glycol methyl ether; The water-based wetting agent used is Tego270, a product of Guangzhou Meihan Trading Co., Ltd.

[0030]

Example 3

[0031] Among them, the water-based organosilicon impregnation water-repellent agent used is RUCOSAN B-WB water-based organosilicon water-repellent agent from Guangdong Jiafucheng Materials Technology Co., Ltd.; The waterborne epoxy resin used is EP-601 waterborne single-component epoxy emulsion from Guangzhou Jiafucheng Trading Co., Ltd. The amino resin used is CY-385 amino resin from Guangzhou Jiafucheng Trading Co., Ltd. The film-forming aid used is dipropylene glycol methyl ether; The water-based wetting agent used is Tego270, a product of Guangzhou Meihan Trading Co., Ltd.

[0032]

Example 4

[0033]

Example 5

[0034] Comparative Example Comparative Example 1 A water-based calcium silicate board coating differs from [Example 2] in that it does not contain amino resin.

[0035] Comparative Example 2 A water-based calcium silicate board coating differs from [Example 2] in that the amounts of each component are different. In this comparative example, the water-based calcium silicate board coating is prepared by uniformly mixing 6 wt% water-based organosilicon impregnation water-repellent agent, 20 wt% water-based epoxy resin, 1.5 wt% amino resin, 5 wt% film-forming aid, 0.6 wt% water-based wetting agent, and the balance water.

[0036] Comparative Example 3 A water-based calcium silicate board coating differs from [Example 4] in that the preparation method of the inorganic modified water-based epoxy resin is different. In this comparative example, the preparation method of the inorganic modified water-based epoxy resin includes the following steps: Prepare a 4% potassium silicate aqueous solution from 2.5 kg of potassium silicate powder. After cooling the potassium silicate aqueous solution to room temperature, a dilute hydrochloric acid solution with a molar concentration of 0.1 mol / L was added dropwise to the potassium silicate aqueous solution while stirring to adjust the pH of the system to 3. Then, the solution was allowed to stand at 25°C for 12 hours to obtain polysilicic acid sol. 1 kg of aminosilane coupling agent KH550 was added to 25 kg of 90% ethanol aqueous solution, and the pH was adjusted to 3.5 with acetic acid. The solution was hydrolyzed at 40℃ for 1 h, and then cooled to room temperature to obtain aminosilane hydrolysate. While stirring, aminosilane hydrolysate was added to the polysilicic acid sol, and the reaction was stirred for 2 hours. Then, 100 kg of waterborne epoxy resin (waterborne single-component epoxy emulsion EP-601 from Guangzhou Jiafucheng Trading Co., Ltd.) was added, stirred evenly, and the pH was adjusted to 8.0 with a sodium hydroxide solution with a molar concentration of 0.5 mol / L. The mixture was stirred evenly to obtain inorganic modified waterborne epoxy resin.

[0037] Performance testing (1) Water droplet angle: The water droplet angle is the water contact angle. The specific test method is as follows: the water-based calcium silicate board coatings of each embodiment and comparative example are sprayed on the surface of the calcium silicate board, and baked at 120°C for 2 minutes to obtain the test sample. A 5μL droplet is transferred to the test surface of the test sample with a needle. The droplet and the contact surface are displayed on the computer image using an optical camera and the contact angle between the droplet and the contact surface is calculated. A total of 5 tests are performed, and the average value of the 5 measurements is taken as the contact angle. The water contact angle is measured using a contact angle tester of model OCA20 purchased from Dataphysics, Germany.

[0038] (2) Insulation resistance value: The water-based calcium silicate board coatings of each embodiment and comparative example were sprayed onto the surface of the calcium silicate board and baked at 120°C for 2 minutes to prepare test samples. Five test samples were taken from each group and placed in a dual 85 environment (temperature 85°C, humidity 85% RH) and a DC bias voltage of 50V was continuously applied for aging. When the aging time reached 168h, the sample was briefly removed from the aging environment, the 50V bias voltage was removed, and the insulation resistance value of its surface coating was measured using a test voltage of 100V in a standard laboratory environment.

[0039] (3) Flame retardant performance: The flame retardant rating was determined according to GB / T 8624-2012. The test samples were prepared from the water-based calcium silicate board coatings in each example and comparative example. The curing conditions of the coating were 120℃ for 2 minutes. The only difference between the test samples was the composition of the coating. The flame retardant rating of A2 or above was considered qualified, otherwise it was considered unqualified.

[0040] (4) Dipping effect: Ten calcium silicate boards were immersed in the water-based calcium silicate board coatings prepared in each example and comparative example, left to stand for 30 seconds, then removed and left to stand until no more droplets fell. They were then transferred to a 120°C environment and hung to bake for 2 minutes. The presence of obvious flow marks was observed, and the thickness and adhesion of the coating film formed on the surface of the calcium silicate board were tested (cross-cut test, the smaller the grade, the better the adhesion). The coating film thickness of 10-15 μm was the best dip coating effect. If the coating film thickness is too small, it is difficult to form an effective protection for the calcium silicate board. If the coating film thickness is too high, it is easy to cause waste.

[0041] Table 1

[0042] Table 2

[0043] Based on the test data in Examples 1-5 and Table 1-2, it can be seen that in this application, the water droplet angle of the water-based calcium silicate board coating is ≥115°, the insulation resistance is >500 megohms, the flame retardant rating is above A2, and when the calcium silicate board is applied by dip coating, a smooth and flat paint film without orange peel or sagging problems can be obtained.

[0044] Based on the test data in Example 2, Comparative Example 1, and Tables 1-2, it can be seen that when no amino resin is added, the insulation resistance value of the paint film is <500 megohms, and the insulation performance of the paint film formed by the water-based calcium silicate board coating decreases.

[0045] Based on the test data in Example 2, Comparative Example 2, and Tables 1-2, it can be seen that when the weight ratio of each component in Comparative Example 2 is not within the scope of this application, the water-based calcium silicate board coating is prone to orange peel phenomenon when dipping calcium silicate board, and the adhesion between the paint film and the calcium silicate board decreases, the insulation resistance value of the paint film is <500 megohms, and the insulation performance of the paint film formed by the water-based calcium silicate board coating decreases.

[0046] Based on the data from Example 2, Comparative Example 3, and Tables 1-2, it can be seen that the potassium silicate-modified waterborne epoxy resins obtained by different preparation methods have different effects on the film-forming properties of waterborne calcium silicate board coatings. Specifically, in Comparative Example 3, when the potassium silicate-modified waterborne epoxy resin was added to the dilute hydrochloric acid solution, the process was not carried out at 0-4°C, and the pH was not controlled within the range of 4.5-5.0 during the hydrolysis of the aminosilane coupling agent. This affected the leveling properties of the waterborne calcium silicate board coating, and the resulting film after dip coating was prone to surface unevenness and localized pinholes.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties, characterized in that: The water-based calcium silicate board coating is prepared from 2-4 wt% water-based organosilicon impregnation water-repellent agent, 28-35 wt% water-based epoxy resin, 4-6 wt% amino resin, 3-5 wt% film-forming aid, 0.4-0.6 wt% water-based wetting agent, and the balance being diluent.

2. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 1, characterized in that: The waterborne epoxy resin is an inorganically modified waterborne epoxy resin, and the preparation method of the inorganically modified waterborne epoxy resin is as follows: Prepare a silicate aqueous solution with a mass concentration of 4-6% by using 2.5-3 parts by weight of silicate powder; While stirring, dilute acid solution is added dropwise to silicate aqueous solution at 0-4℃ to adjust the pH of the system to 3-4, and then the system is allowed to stand at 25-30℃ for 6-12 hours to obtain polysilicic acid sol. Prepare an aqueous solution of aminosilane coupling agent by mixing 1-1.5 parts by weight of aminosilane coupling agent with 50 parts by weight of water, adjust the pH to 4.5-5.0, hydrolyze at 40-50℃ for 0.5-1h, and then cool to room temperature to obtain aminosilane hydrolysate. While stirring, add aminosilane hydrolysate to the polysilicic acid sol and stir for 2-3 hours. Then add 100 parts by weight of waterborne epoxy resin, stir evenly, adjust the pH to 8-8.5, and stir evenly to obtain inorganic modified waterborne epoxy resin.

3. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 2, characterized in that: The dilute acid solution is a dilute hydrochloric acid solution with a molar concentration of 1-1.5 mol / L.

4. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 2, characterized in that: The aminosilane coupling agent is a primary aminosilane coupling agent.

5. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 2, characterized in that: The silicate is at least one of sodium silicate and potassium silicate.

6. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 1, characterized in that: The water-based organosilicon impregnation water-repellent agent used is RUCOSAN B-WB.

7. The water-based calcium silicate board coating with superhydrophobic, highly efficient insulating and flame-retardant properties according to claim 1, characterized in that: The film-forming aid is a propylene glycol ether-based film-forming aid.

8. A method for preparing a water-based calcium silicate board coating as described in any one of claims 1-7, characterized in that, Includes the following steps: After uniformly mixing the film-forming aid, water-based wetting agent, and diluent, add the water-based organosilicon impregnation water-repellent agent, water-based epoxy resin, and amino resin, and stir evenly to obtain the water-based calcium silicate board coating.

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