Preparation method and application of hydrophobic colorful coating

Abstract

The invention discloses a preparation method of a hydrophobic colorful coating, which comprises the following steps: step 1, base material pretreatment: cleaning the surface of a calcium silicate board until no oil stain or floating ash exists, and carrying out sealing treatment by using an alkali-resistant sealing primer; step 2, preparation of a colorful functional layer: mixing protective glue magnesium lithium silicate (2wt%), aqueous acrylic emulsion EQ143 (40wt%), aqueous color paste iron oxide red, iron oxide yellow, carbon black (2wt%), kaolin (2wt%), an aqueous dispersant SN-5040 (0.5 wt%), texanol (1wt%), propylene glycol (0.5 wt%) and deionized water (52wt%), granulating to prepare an aqueous colorful coating, and spraying and drying to prepare the colorful stone-like coating; and 3, constructing a hydrophobic layer: preparing the super-hydrophobic surface composite coating with a secondary structure by adopting micron and nano silicon dioxide. The hydrophobic colorful coating prepared by the preparation method of the hydrophobic colorful coating provided by the invention is excellent in hydrophobic performance (the contact angle reaches 162.5 degrees) and strong in pollution resistance; and the stone imitation effect is vivid.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and more specifically to a method for preparing a hydrophobic multicolor coating. Background Technology

[0002] Traditional hydrophobic coatings (such as fluorocarbon coatings) are waterproof, but their colors are limited and cannot meet decorative needs; multi-colored coatings (such as water-based multi-colored paints) have rich visual effects, but their hydrophobic properties are poor and they are easily contaminated or corroded; in existing technologies, it is difficult to optimize hydrophobicity and multi-colored imitation stone in a synergistic way.

[0003] Patent CN119639260A discloses a "method for preparing superhydrophobic nanocoatings", but it does not solve the problem of the coating having a single color.

[0004] The paper "Optical Magic - Colorful Microstructures" proposes using microspheres to achieve multicolored effects, but the hydrophobic properties are insufficient (contact angle < 120°).

[0005] Therefore, how to provide a method for preparing and applying highly hydrophobic multicolor coatings is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a method for preparing a coating that combines high hydrophobicity (contact angle ≥150°) and colorful stone-like effect.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a hydrophobic multicolor coating includes the following steps: Step 1: Substrate Pretreatment Substrate treatment: Clean the surface of the calcium silicate board to remove oil and dust, and seal it with an alkali-resistant sealing primer ST-D900; Step 2: Preparation of Multi-Color Functional Layers A water-based multicolor coating is prepared by mixing protective colloid, water-based acrylic emulsion, water-based color paste, kaolin, water-based additives, and deionized water, and then spraying and drying it to obtain a multicolor stone-like coating. Step 3: Construction of the hydrophobic layer: A superhydrophobic surface composite coating with a secondary structure is prepared using micron and nano silica.

[0008] Preferably, the construction of the hydrophobic layer specifically includes: (1) Synthesis of prepolymer and preparation of dispersion 1) Dehydration HTPB is subjected to vacuum dehydration to remove small molecules and water. 2) Prepolymerization Acetone and TDI were added to the dehydrated HTPB and prepolymerized under external cooling water circulation to obtain polyurethane prepolymer. 3) Preparation of micron-sized silica dispersion Micron-sized silica was placed in a flask, acetone was weighed and mixed with silica, and the coupling agent MOCA was added dropwise. The mixture was then ultrasonically dispersed to obtain a micron-sized silica dispersion. 4) Preparation of nano-silica dispersion Place nano-silica in a flask, weigh out acetone and mix with silica, add coupling agent MOCA dropwise, and then disperse by ultrasonication to obtain nano-silica dispersion; 5) Preparation of hydroxyl silicone oil modified polyurethane solution Dissolve the polyurethane prepolymer in acetone and dilute it to a concentration of 5.0 wt%. Dissolve the polyurethane prepolymer in acetone, then add an appropriate amount of hydroxyl silicone oil to make -NCO:-OH = 1:1, and dilute the polyurethane prepolymer solution to a concentration of 1.0 wt%. (2) Surface modification Micron-sized silica dispersion, nano-sized silica dispersion, and hydroxyl silicone oil-modified polyurethane solution were applied to a multi-colored imitation stone coating and then dried.

[0009] Organic chains are grafted onto the surface of micron- and nano-sized silica through addition reactions between the -OH groups on the surface of the prepolymer and the -NCO groups. Under ultrasonic vibration, the grafted micron- and nano-sized silica are uniformly dispersed in acetone solvent to form a stable suspension. The grafted micron- and nano-sized silica then undergo chain extension reactions with the curing agent and polyurethane prepolymer, sequentially fixing the silica onto the substrate surface and forming a uniform rough surface with a micron- and nano-level secondary structure. Hydroxyl silicone oil is a low surface energy material, and the hydroxyl groups in its chains participate in the decomposition reaction of polyurethane. Low surface energy segments tend to converge to the surface to form a low surface energy layer. The micron- and nano-level secondary structure of the surface, combined with its chemical composition, forms a hydrophobic coating with a lotus leaf structure and function.

[0010] Preferably, the proportions of each component in the multi-colored functional layer in step 2 are as follows: 2wt% protective adhesive, 40wt% water-based acrylic emulsion, 2wt% water-based color paste, 2wt% kaolin, 2wt% water-based additives, and 52wt% deionized water.

[0011] Preferably, the protective adhesive is lithium magnesium silicate; The aqueous acrylic emulsion is EQ143; The water-based pigment is a mixture of iron oxide red, iron oxide yellow and carbon black in any proportion; The aqueous additives include aqueous dispersant SN-5040, alcohol ester dodecyl and propylene glycol.

[0012] Preferably, the vacuum dehydration treatment in step 1) is a vacuum dehydration treatment at 50°C for 1 hour.

[0013] Preferably, in step 2), the TDI has a -NCO:-OH ratio of 2.3:1; the prepolymerization reaction is carried out by heating at 50°C for 2.5 hours.

[0014] Preferably, in steps 3) and 4), the coupling agent MOCA has a -NH2:-NCO ratio of 2:1.

[0015] Another object of the present invention is to provide the application of the hydrophobic multicolor coating prepared by the above-mentioned method in the surface protection and decoration of building decorative panels.

[0016] As can be seen from the above technical solution, compared with the prior art, the hydrophobic multicolor coating prepared by the method of the present invention has excellent hydrophobic properties (contact angle up to 162.5°), strong anti-fouling properties, and realistic stone-like effect. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 SEM micrograph of the hydrophobic coating; Figure 2 Photos showing the stone-like effect of a multi-colored coating; Figure 3 This is a graph showing the contact angle test results. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0020] Example 1 This embodiment provides a method for preparing a hydrophobic multicolor coating, including the following steps: Step 1: Substrate Pretreatment Substrate treatment: Clean the surface of the calcium silicate board to remove oil and dust, and seal it with an alkali-resistant sealing primer ST-D900.

[0021] Step 2: Preparation of Multi-Color Functional Layers A water-based multicolor coating was prepared by mixing 2 wt% lithium magnesium silicate protective colloid, 40 wt% water-based acrylic emulsion EQ143, 2 wt% water-based color paste (iron red, iron yellow and carbon black mixed in a 1:1:1 ratio), 2 wt% kaolin, 0.5 wt% water-based dispersant SN-5040, 1 wt% alcohol ester dodecyl, 0.5 wt% propylene glycol and 52 wt% deionized water, and granulating the mixture. The resulting multicolor imitation stone coating was obtained by spraying and drying. Step 3: Construction of the hydrophobic layer: A superhydrophobic surface composite coating with a secondary structure is prepared using micron and nano silica.

[0022] (1) Synthesis of prepolymer and preparation of dispersion 1) Dehydration Take 10g of HTPB and dehydrate it under vacuum at 50°C for 1 hour to remove small molecules and water.

[0023] 2) Prepolymerization 10g of acetone and 1.8g of TDI (-NCO:-OH=2.3:1) were added to the dehydrated HTPB and heated for 2.5h (heating temperature 50°C) under external cooling water circulation to carry out the prepolymerization reaction.

[0024] 3) Preparation of micron-sized silica dispersion Place 1.0 g of micron-sized silica in a flask, weigh 97.2 g of acetone and mix with silica, add 1.8 g of coupling agent MOCA (-NH2:-NCO=2:1) ​​dropwise, and then perform ultrasonic dispersion for 0.5 h.

[0025] 4) Preparation of nano-silica dispersion Place 1.0g of nano-silica in a flask, weigh 99g of acetone and mix with silica, add 1.8g of coupling agent MOCA (-NH2:-NCO=2:1) ​​dropwise, and then perform ultrasonic dispersion for 0.5h.

[0026] 5) Preparation of hydroxyl silicone oil modified polyurethane solution Dissolve the polyurethane prepolymer in acetone and dilute it to a concentration of 5.0 wt%. Dissolve the polyurethane prepolymer in acetone, then add an appropriate amount of hydroxyl silicone oil to make -NCO:-OH = 1:1, and dilute the polyurethane prepolymer solution to a concentration of 1.0 wt%. (2) Surface modification Micron-sized silica dispersion, nano-sized silica dispersion, and hydroxyl silicone oil-modified polyurethane solution were applied to a multi-colored coating and then dried.

[0027] See Figure 1-3 , Figure 1 The image shows a SEM micrograph of the hydrophobic coating, revealing the superhydrophobic surface morphology with a micro-nano secondary structure. Figure 3 The image shows the contact angle test results, with a contact angle of 162.5°.

[0028] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0029] 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 method for preparing a hydrophobic multicolor coating, characterized in that... It boasts excellent hydrophobic properties and strong stain resistance; the stone-like effect is realistic, and the process includes the following steps: Step 1: Substrate Pretreatment Substrate treatment: Clean the surface of the calcium silicate board, removing oil and dust, and seal it with an alkali-resistant sealing primer; Step 2: Preparation of Multi-Color Functional Layers A water-based multicolor coating is prepared by mixing protective colloid, water-based acrylic emulsion, water-based color paste, kaolin, water-based additives, and deionized water, and then spraying and drying it to obtain a multicolor stone-like coating. Step 3: Construction of the hydrophobic layer A superhydrophobic surface composite coating with a secondary structure was prepared using micron- and nano-sized silica.

2. The method for preparing a hydrophobic multicolor coating according to claim 1, characterized in that, The construction of the hydrophobic layer specifically includes: (1) Synthesis of prepolymer and preparation of dispersion 1) Dehydration HTPB is subjected to vacuum dehydration to remove small molecules and water. 2) Prepolymerization Acetone and TDI were added to the dehydrated HTPB and prepolymerized under external cooling water circulation to obtain polyurethane prepolymer. 3) Preparation of micron-sized silica dispersion Micron-sized silica was placed in a flask, acetone was weighed and mixed with silica, and the coupling agent MOCA was added dropwise. The mixture was then ultrasonically dispersed to obtain a micron-sized silica dispersion. 4) Preparation of nano-silica dispersion Place nano-silica in a flask, weigh out acetone and mix with silica, add coupling agent MOCA dropwise, and then disperse by ultrasonication to obtain nano-silica dispersion; 5) Preparation of hydroxyl silicone oil modified polyurethane solution Dissolve the polyurethane prepolymer in acetone and dilute it to a concentration of 5.0 wt%. Dissolve the polyurethane prepolymer in acetone, then add an appropriate amount of hydroxyl silicone oil to make -NCO:-OH = 1:1, and dilute the polyurethane prepolymer solution to a concentration of 1.0 wt%. (2) Surface modification Micron-sized silica dispersion, nano-sized silica dispersion, and hydroxyl silicone oil-modified polyurethane solution were applied to a multi-colored imitation stone coating and then dried.

3. The method for preparing a hydrophobic multicolor coating according to claim 2, characterized in that, The alkali-resistant sealing primer is ST-D900.

4. The method for preparing a hydrophobic multicolor coating according to claim 2, characterized in that, The proportions of each component in the multi-colored functional layer described in step 2 are as follows: 2wt% protective colloid, 40wt% water-based acrylic emulsion, 2wt% water-based color paste, 2wt% kaolin, 2wt% water-based additives, and 52wt% deionized water.

5. The method for preparing a hydrophobic multicolor coating according to claim 4, characterized in that, The protective adhesive is lithium magnesium silicate; The aqueous acrylic emulsion is EQ143; The water-based pigment is a mixture of iron oxide red, iron oxide yellow and carbon black in any proportion; The aqueous additives include aqueous dispersant SN-5040, alcohol ester dodecyl and propylene glycol.

6. The method for preparing a hydrophobic multicolor coating according to claim 2, characterized in that, The vacuum dehydration treatment mentioned in step 1) is a vacuum dehydration treatment at 50°C for 1 hour.

7. The method for preparing a hydrophobic multicolor coating according to claim 2, characterized in that, Step 2) The TDI has a -NCO:-OH ratio of 2.3:1; the prepolymerization reaction is carried out by heating at 50°C for 2.5 hours.

8. The method for preparing a hydrophobic multicolor coating according to claim 2, characterized in that, In steps 3) and 4), the coupling agent MOCA has a -NH2:-NCO ratio of 2:

1.

9. The application of a hydrophobic multicolor coating prepared by the method of any one of claims 2-8 in the surface protection and decoration of building decorative panels.

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