Water-based paint for color aluminum plate and preparation process of water-based paint

Abstract

The invention relates to the technical field of coatings, in particular to a water-based coating for a color aluminum plate and a preparation process of the water-based coating. The invention relates to a water-based coating for a color aluminum plate, which is prepared from water-based acrylic emulsion, water-based epoxy resin, water-based isocyanate, an MOF material, rutile titanium dioxide, a cosolvent, a dispersing agent, a neutralizing agent, a defoaming agent, a flatting agent, a base material wetting agent, a thickening agent and water. The preparation process comprises the steps of pigment pre-dispersion, resin mixing, mixing and uniform blending, additive adding, viscosity and pH value adjusting, filtering and packaging. By optimizing the selection of a water-based resin base material and a curing agent, adopting a water-based acrylic emulsion as a main film-forming substance, adopting water-based epoxy resin as a modifier and introducing water-based isocyanate and an MOF material, the coating curing speed is improved, the baking time is shortened, and the required temperature is reduced through the ratio of auxiliaries and a preparation process; energy consumption is reduced, and problems caused by high-temperature baking are avoided, so that the quality and durability of the coating are improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a water-based coating for color aluminum plates and a preparation process thereof. Background Art

[0002] Water-based paint for color aluminum is an environmentally friendly paint designed for the surface of color aluminum. It uses water as a diluent and has the advantages of low VOC emissions, no irritating odor, easy construction, and fast drying. The paint can be evenly attached to the surface of the color aluminum to form a smooth, weather-resistant coating, which not only improves the decorative effect of the color aluminum, but also prolongs its service life. At the same time, the environmental protection characteristics of water-based paint also meet the requirements of modern construction and manufacturing for sustainable development.

[0003] The existing water-based paint for color aluminum plates usually requires a high temperature and a long time to achieve the curing of the coating during the baking process, which not only consumes a lot of energy and increases production costs, but also causes quality problems such as discoloration and cracking of the coating due to high-temperature baking, affecting the appearance and performance of the product. At the same time, high-temperature baking may also cause thermal stress to the metal substrate, affecting its mechanical properties and durability. Therefore, a water-based paint for color aluminum plates and a preparation process thereof are needed to solve the above problems. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a water-based coating for color aluminum plates and a preparation process thereof.

[0005] A water-based paint for a color aluminum plate is composed of the following raw materials in parts by weight: 40-45 parts of water-based acrylic emulsion, 10-15 parts of water-based epoxy resin, 15-20 parts of water-based isocyanate, 1-3 parts of MOF material, 12-18 parts of rutile titanium dioxide, 2-3 parts of cosolvent, 1-3 parts of dispersant, 0.1-0.2 parts of neutralizer, 0.2-0.4 parts of defoamer, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of substrate wetting agent, 0.5-1.0 parts of thickener and 10-15 parts of deionized water.

[0006] Furthermore, the co-solvent is one or a combination of propylene glycol butyl ether and propylene glycol methyl ether, and the total amount is 2-3 parts by weight.

[0007] Furthermore, the dispersant is a polymer dispersant, including sodium polyacrylate or polyvinyl alcohol; and the neutralizer is an amine neutralizer.

[0008] Furthermore, the leveling agent is a fluorocarbon modified siloxane leveling agent, which can significantly improve the leveling and glossiness of the coating.

[0009] Furthermore, the thickener is a compound system of hydroxyethyl cellulose and polyurethane thickener, and the amount thereof is adjusted according to the required viscosity to ensure the stability and operability of the coating during the construction process.

[0010] As one of the main film-forming substances of coatings, water-based acrylic emulsion is made through emulsion polymerization. It has excellent weather resistance, water resistance and good adhesion. During the film-forming process, the polymer particles in the emulsion gradually fuse to form a dense network structure, providing basic physical and chemical properties for the coating.

[0011] Based on its good film-forming properties, adhesion, weather resistance and high strength, water-based epoxy resin can form a tough and uniform coating on the surface of the color aluminum plate, effectively protecting the substrate from erosion by the external environment, and working together with acrylic emulsion to form a tougher and more durable coating.

[0012] As a cross-linking curing agent for coatings, water-based isocyanate has high reactivity. Under heating conditions, it undergoes chemical cross-linking reaction with functional groups such as hydroxyl and carboxyl in the resin to form a three-dimensional network structure, thereby enhancing the interaction between coating molecules, and enhancing the hardness and wear resistance of the coating. The occurrence of the curing reaction makes the coating have a higher cross-linking density and better physical properties after drying.

[0013] MOF materials, the full name of which is metal organic framework (MOFs) materials, are highly ordered three-dimensional network structure materials formed by self-assembly of metal ions or metal clusters and organic ligands through coordination bonds. This material combines the rigidity of inorganic materials and the flexibility of organic materials, and has many unique physical and chemical properties. In coatings, the microscopic negative pressure cavity structure formed by MOF materials can reduce the thermal conductivity of the coating and reduce the transfer of heat in the coating, thereby improving the thermal insulation performance of the coating, which helps to reduce the temperature gradient on the surface of the coating during baking and reduce the quality problems such as discoloration and cracking of the coating caused by high-temperature baking. MOF materials themselves have excellent weather resistance and can resist the erosion of environmental factors such as ultraviolet rays and humidity on the coating. Introducing them into coatings can further improve the weather resistance of the coating and extend the service life of the coating; MOF materials are evenly dispersed in the coating matrix as nanofillers, forming a good interface with matrix materials such as resins, which can enhance the mechanical properties and toughness of the coating, which helps to reduce the problems of cracking and peeling of the coating caused by thermal stress during baking.

[0014] Cosolvents such as propylene glycol butyl ether and propylene glycol methyl ether help to reduce the viscosity of the coating system, improve the dispersion of the pigment and the fluidity of the coating. At the same time, they can also promote the mutual penetration and reaction of the resin and the curing agent, and improve the crosslinking density and performance of the coating.

[0015] Amine neutralizers are used to adjust the pH value of the coating to keep it within an appropriate range. An appropriate pH value helps maintain the stability and construction performance of the coating while promoting the reaction between the resin and the curing agent.

[0016] Defoaming agent, leveling agent, substrate wetting agent: These additives are used to eliminate bubbles in the paint, improve the leveling of the paint, and increase the wettability of the paint on the color aluminum plate. They work together to make the paint smoother during the construction process and the coating film smoother.

[0017] A preparation process of water-based paint for color aluminum plate, comprising the following steps: Step 1: Resin mixing: The pretreated MOF material is prepared into a nano-scale dispersion by ultrasonic dispersion or ball milling; in a preparation pot, the water-based acrylic emulsion, water-based epoxy resin and water-based isocyanate are evenly mixed, and the pretreated MOF material dispersion is slowly added under stirring to obtain a resin mixture at a stirring speed of 150-300r / min; Step 2: Pigment pre-dispersion: add half of the deionized water, dispersant and rutile titanium dioxide into another container, stir and mix evenly, and then grind into a sand mill to obtain a pigment slurry; Step 3: Mix and blend: Slowly add the pigment slurry into the resin mixture and stir at a speed of 500-600r / min to ensure that the pigment is evenly dispersed; Step 4: Adding additives: Under stirring, add the cosolvent, neutralizer, and remaining deionized water in sequence, increase the stirring speed to 900-1000r / min, and continue stirring for 10-15 minutes. Subsequently, add the defoamer, leveling agent, and substrate wetting agent in succession, increase the stirring speed to 1200-1500r / min, and stir for 10-15 minutes to obtain the coating base material; Step 5: Viscosity and pH adjustment: Add thickener to the coating base, stir at 1000-1200r / min for 15-25 minutes, measure with Stormer viscometer, adjust viscosity to 90-110KU, and adjust pH to 8.0-8.5 with sodium bicarbonate or other pH adjuster; Step 6: Filtration and packaging: Use a 200-400 mesh filter to filter the paint base material to remove impurities, obtain water-based paint for colored aluminum plates, and finally package it in a sealed container.

[0018] Specifically, in step 1, the pretreatment is to use a silane coupling agent to perform surface treatment on the MOF material.

[0019] Furthermore, in step 2, the resin mixing process is carried out under vacuum conditions to remove bubbles generated during the mixing process and improve the uniformity and quality of the coating.

[0020] Furthermore, in step three, ultrasonic dispersion technology is used to assist the addition of the pigment slurry, that is, while the pigment slurry is slowly added to the resin mixture, the mixture is ultrasonically treated with an ultrasonic generator, and the frequency of the ultrasound is set to 20-40kHz. The treatment time is the entire process of the pigment slurry addition or a specific time period, including the first 5 minutes of the addition process, 60-80% of the total addition time, 5 minutes after the addition, or other time periods.

[0021] Furthermore, in step 4, an environmentally friendly solvent is introduced to replace the co-solvent. The environmentally friendly solvent includes acetates and lactates. In the preparation pot, the rutile titanium dioxide and the dispersant are fully mixed and refined to the micron level through stirring and sand mill grinding. The dispersant is adsorbed on the surface of the pigment particles to form a protective film to prevent the pigment particles from agglomerating and ensure the uniform dispersion of the pigment in the coating. In the process of adding the pigment slurry to the resin mixture, ultrasonic dispersion technology is used to further promote the uniform dispersion of the pigment particles. The cavitation effect and micro jet generated by the ultrasonic wave can break the pigment agglomerates, making the pigment particles smaller and more evenly dispersed in the resin mixture, thereby improving the fineness and glossiness of the coating.

[0022] The beneficial effects achieved by the present invention are as follows: 1. The present invention optimizes the selection of water-based resin base materials and curing agents, adopts water-based acrylic emulsions and water-based epoxy resins as main film-forming substances, utilizes the synergistic effect of the two resins to make the coating tightly adhere to the substrate, and adds water-based isocyanate and MOF materials. The water-based isocyanate has high reactivity and fast curing speed, can achieve effective cross-linking at a relatively low temperature, and chemically reacts with the water-based acrylic emulsion and the water-based epoxy resin to form a tightly cross-linked network. The porous structure and rich functional groups of the MOF material can promote the cross-linking reaction of the matrix materials such as the resin in the coating, thereby accelerating the curing process, shortening the baking time and reducing the required temperature; the high specific surface area and porosity of the MOF material can improve the thermal conductivity efficiency inside the coating, so that the heat is transferred to the inside of the coating faster, and the curing reaction is promoted. It can not only reduce energy consumption and improve baking efficiency, but also avoid the problems of coating discoloration and cracking that may be caused by high-temperature baking, thereby improving the quality and durability of the coating.

[0023] 2. The present invention selects water-based acrylic emulsion as the main body and water-based epoxy resin as the modifier through reasonable ratio and process optimization. By introducing modified water-based epoxy resin and water-based isocyanate, the coating resin can undergo cross-linking reaction at a lower temperature, thereby improving the curing speed and baking efficiency of the coating and ensuring the high performance of the coating. At the same time, the use of rutile titanium dioxide improves the covering power and whiteness of the coating, and the addition of leveling agent and substrate wetting agent ensures the smoothness and uniformity of the coating. At the same time, the excellent weather resistance and UV resistance of rutile titanium dioxide can be used to effectively reflect ultraviolet rays and slow down the aging rate of the coating, thereby extending the service life of the coating.

[0024] 3. The preparation process of the present invention adopts the steps of pigment pre-dispersion, resin mixing, mixing and blending, and ensures the uniformity and stability of the coating by accurately controlling the stirring speed and dispersion technology. In addition, the compound system of the thickener makes the viscosity adjustment more flexible and convenient for construction.

[0025] 4. The present invention introduces steps such as vacuum mixing, ultrasonic dispersion and heat treatment in the preparation process to effectively remove bubbles generated during the mixing process, improve the uniformity and quality of the coating, and at the same time, accurately control the viscosity and pH value of the coating through a Stormer viscometer and a pH adjuster to ensure the stability and consistency of product quality.

[0026] 5. The preparation process of the present invention is simple, the preparation process is easy to control, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic flow chart of a process for preparing a colored aluminum plate using a water-based coating according to an embodiment of the present invention; Figure 2 The raw material formula of the water-based coating for the color aluminum plate used in Examples 1 to 3 of the present invention; Figure 3 The test results of the curing speed, baking temperature, VOC content, adhesion and weather resistance of the water-based coatings used in Examples 1 to 3 of the present invention for the color aluminum plates; Figure 4 These are the test results of the hardness, acid and alkali resistance, viscosity, leveling and glossiness of the colored aluminum plates used in Examples 1 to 3 of the present invention using water-based coatings. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0029] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0030] When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the present invention belongs.

[0031] The raw materials used in the following examples, unless otherwise specified, are all common commercially available products.

[0032] Example 1: A water-based paint for color aluminum plate, such as Figure 2 As shown, it is composed of the following raw materials in parts by weight: 40 parts of water-based acrylic emulsion, 10 parts of water-based epoxy resin, 15 parts of water-based isocyanate, 2 parts of MOF material (ZIF-8), 15 parts of rutile titanium dioxide, 2 parts of co-solvent (propylene glycol butyl ether), 1 part of dispersant (sodium polyacrylate), 0.1 part of neutralizer (amine neutralizer Angus AMP-95), 0.2 part of defoamer (mineral oil defoamer), 0.3 part of leveling agent (fluorocarbon modified siloxane leveling agent), 0.3 part of substrate wetting agent (polyether modified silicone), 0.5 part of thickener (1:1 compound system of hydroxyethyl cellulose and polyurethane thickener) and 10 parts of deionized water.

[0033] A preparation process of water-based paint for color aluminum plate, such as Figure 1 As shown, the following steps are included: Step 1: Resin mixing: The pretreated MOF material is prepared into a nano-scale dispersion by ultrasonic dispersion; in a preparation pot, the water-based acrylic emulsion, water-based epoxy resin and water-based isocyanate are mixed evenly, and the resin mixing process is carried out under vacuum conditions. Under stirring, the pretreated MOF material dispersion is slowly added to obtain a resin mixture, and the stirring speed is 150r / min; Step 2: Pigment pre-dispersion: add half of the deionized water, dispersant and rutile titanium dioxide into another container, stir and mix evenly, and then grind into a sand mill to obtain a pigment slurry; Step 3: Mixing and blending: slowly add the pigment slurry into the resin mixture, and stir at a speed of 500r / min to ensure that the pigment is evenly dispersed. During this period, ultrasonic dispersion technology is used to assist the addition of the pigment slurry, that is, while the pigment slurry is slowly added to the resin mixture, the mixture is ultrasonically treated with an ultrasonic generator. The frequency of the ultrasonic wave is set to 20kHz, and the treatment time is the first 5 minutes of the pigment slurry addition process; Step 4: Adding additives: Under stirring, add the cosolvent, neutralizer, and remaining deionized water in sequence, increase the stirring speed to 900r / min, and continue stirring for 10 minutes. Then, add the defoamer, leveling agent, and substrate wetting agent in succession, increase the stirring speed to 1200r / min, and stir for 10 minutes to obtain the coating base material; Step 5: Viscosity and pH adjustment: Add thickener to the coating base, stir at 1000r / min for 15 minutes, use Stormer viscometer to measure, adjust the viscosity to 90KU, and use sodium bicarbonate to adjust the pH to 8.0; Step 6: Filtration and packaging: Use a 200-mesh filter to filter the paint base material to remove impurities, obtain water-based paint for colored aluminum plates, and finally package it in a sealed container.

[0034] Example 2: A water-based paint for color aluminum plate, such as Figure 2 As shown, it is composed of the following raw materials in parts by weight: 42 parts of water-based acrylic emulsion, 12 parts of water-based epoxy resin, 17 parts of water-based isocyanate, 1 part of MOF material (MIL-101), 18 parts of rutile titanium dioxide, 2.5 parts of cosolvent (propylene glycol methyl ether), 2 parts of dispersant (polyvinyl alcohol), 0.15 parts of neutralizer (amine neutralizer Angus AMP-95), 0.3 parts of defoamer (mineral oil defoamer), 0.4 parts of leveling agent (fluorocarbon modified siloxane leveling agent), 0.4 parts of substrate wetting agent (polyether modified silicone), 0.7 parts of thickener (1.5:1 compound system of hydroxyethyl cellulose and polyurethane thickener) and 12 parts of deionized water.

[0035] A preparation process of water-based paint for color aluminum plate, such as Figure 1 As shown, the following steps are included: Step 1: Resin mixing: The pretreated MOF material is prepared into a nano-scale dispersion by ball milling; in a preparation pot, the water-based acrylic emulsion, water-based epoxy resin and water-based isocyanate are mixed evenly. The resin mixing process is carried out under vacuum conditions. Under stirring, the pretreated MOF material dispersion is slowly added to obtain a resin mixture at a stirring speed of 220 r / min. Step 2: Pigment pre-dispersion: add half of the deionized water, dispersant and rutile titanium dioxide into another container, stir and mix evenly, and then grind into a sand mill to obtain a pigment slurry; Step 3: Mixing and blending: slowly add the pigment slurry into the resin mixture, stirring at a speed of 550r / min to ensure uniform dispersion of the pigment. Ultrasonic dispersion technology is used to assist the addition of the pigment slurry, that is, while the pigment slurry is slowly added to the resin mixture, an ultrasonic generator is used to perform ultrasonic treatment on the mixture. The frequency of the ultrasonic wave is set to 30kHz, and the treatment time is the first 5 minutes of the pigment slurry addition process. Step 4: Adding additives: Under stirring, add the cosolvent, neutralizer, and remaining deionized water in sequence, increase the stirring speed to 950r / min, and continue stirring for 12 minutes. Then, add the defoamer, leveling agent, and substrate wetting agent in succession, increase the stirring speed to 1350r / min, and stir for 12 minutes to obtain the coating base material; Step 5: Viscosity and pH adjustment: Add thickener to the coating base, stir at 1100r / min for 20 minutes, measure with Stormer viscometer, adjust viscosity to 100KU, and adjust pH to 8.2 with sodium bicarbonate; Step 6: Filtration and packaging: Use a 300-mesh filter to filter the paint base material to remove impurities, obtain water-based paint for colored aluminum plates, and finally package it in a sealed container.

[0036] Example 3: A water-based paint for color aluminum plate, such as Figure 2 As shown, it is composed of the following raw materials in parts by weight: 45 parts of water-based acrylic emulsion, 15 parts of water-based epoxy resin, 20 parts of water-based isocyanate, 3 parts of MOF material (UiO-66), 12 parts of rutile titanium dioxide, 3 parts of cosolvent (propylene glycol butyl ether), 3 parts of dispersant (sodium polyacrylate), 0.2 parts of neutralizer (amine neutralizer Angus AMP-95), 0.4 parts of defoamer (mineral oil defoamer), 0.5 parts of leveling agent (fluorocarbon modified siloxane leveling agent), 0.5 parts of substrate wetting agent (polyether modified silicone), 1 part of thickener (1:1 compound system of hydroxyethyl cellulose and polyurethane thickener) and 15 parts of deionized water.

[0037] A preparation process of water-based paint for color aluminum plate, such as Figure 1 As shown, the following steps are included: Step 1: Resin mixing: The pretreated MOF material is prepared into a nano-scale dispersion by ultrasonic dispersion; in a preparation pot, the water-based acrylic emulsion, water-based epoxy resin and water-based isocyanate are mixed evenly, and the resin mixing process is carried out under vacuum conditions. Under stirring, the pretreated MOF material dispersion is slowly added to obtain a resin mixture at a stirring speed of 300r / min; Step 2: Pigment pre-dispersion: add half of the deionized water, dispersant and rutile titanium dioxide into another container, stir and mix evenly, and then grind into a sand mill to obtain a pigment slurry; Step 3: Mixing and blending: slowly add the pigment slurry into the resin mixture, stirring at a speed of 600r / min to ensure uniform dispersion of the pigment. Ultrasonic dispersion technology is used to assist the addition of the pigment slurry, that is, while the pigment slurry is slowly added to the resin mixture, an ultrasonic generator is used to perform ultrasonic treatment on the mixture. The frequency of the ultrasonic wave is set to 40kHz, and the treatment time is the first 5 minutes of the pigment slurry addition process. Step 4: Adding additives: Under stirring, add the cosolvent, neutralizer, and remaining deionized water in sequence, increase the stirring speed to 1000r / min, and continue stirring for 15 minutes. Then, add the defoamer, leveling agent, and substrate wetting agent in succession, increase the stirring speed to 1500r / min, and stir for 15 minutes to obtain the coating base material; Step 5: Viscosity and pH adjustment: Add thickener to the coating base, stir at 1200r / min for 25 minutes, use Stormer viscometer to measure, adjust the viscosity to 110KU, and use sodium bicarbonate to adjust the pH to 8.5; Step 6: Filtration and packaging: Use a 400-mesh filter to filter the paint base material to remove impurities, obtain water-based paint for colored aluminum plates, and finally package it in a sealed container.

[0038] Comparative Example: Aqueous polyurethane emulsion is used to replace aqueous acrylic emulsion, alkyd resin is used to replace aqueous epoxy resin, urea formaldehyde resin curing agent is used to replace aqueous isocyanate, MOF material is not used, and other raw material compositions and preparation processes are consistent with Example 1.

[0039] Performance test: The water-based coatings for the color aluminum plates prepared in Examples 1 to 3 and the comparative example were tested for environmental performance, physical properties, construction performance, appearance and color performance, including curing speed, baking temperature, VOC content, adhesion, weather resistance, hardness, acid and alkali resistance, viscosity, leveling, and glossiness; Curing speed: The color aluminum plate was coated with water-based paint and baked at 80°C. After curing for 30 minutes, the pencil hardness was tested to evaluate the curing speed.

[0040] Baking temperature: select three baking temperature points, namely 100℃, 60℃ and 40℃, bake the color aluminum plate with water-based paint coating at different temperatures, and set the baking time to 2h to evaluate the curing effect.

[0041] VOC content: The VOC content of water-based coatings for color aluminum panels is tested according to standard ISO11890-2-2006.

[0042] Adhesion: The color aluminum plate is tested with water-based paint coatings for 100 grids, and the passing standard is 1cm 2 Within the range, the Hundred Grid Knife can cut 100 grids without any 100 grids falling off.

[0043] Weather resistance: Use UV aging tester to test the water-based paint coating on color aluminum plate, select UVB-313 lamp, and set the light intensity to 0.62W / m 2 , illumination temperature 80℃, illumination time 20h, condensation illumination intensity 0W / m 2 , condensation temperature 50℃, condensation time 4h, test time 100h, and the color difference value ΔE less than 1% is the qualified indicator.

[0044] Hardness: Use Mitsubishi pencil to test the hardness of water-based paint coating on color aluminum plate. The hardness is not less than F, which is a qualified index.

[0045] Acid and alkali resistance: The color aluminum plate is coated with water-based paint in 5% hydrochloric acid or 5% sodium hydroxide for 7 days. If the coating does not fall off or bubble, it is qualified.

[0046] Viscosity: Use a Tu-4 cup viscometer at S / 25±1℃ to measure the viscosity of water-based paint for color aluminum plates according to GB / T1723 standard. The viscosity value is qualified when it is between 40-150s.

[0047] Leveling: Use the ASTM D2801 standard scraper method to scrape the colored aluminum plate with water-based paint on the substrate and observe the leveling performance of the paint.

[0048] Glossiness: Use BYK-Gardner gloss test to measure the 60° reflective glossiness of the colored aluminum plate with water-based paint coating. The glossiness of the colored paint>82 is qualified.

[0049] Test results from Figure 3 and Figure 4 It can be seen that the water-based coatings for the colored aluminum plates of all embodiments perform well in environmental performance, physical properties, construction performance, appearance and color performance. Specifically, the curing speed is fast at a lower temperature and the curing is complete at a lower baking temperature, which proves that the coating has a good curing effect; the VOC content is not detected, which further proves that the low volatile organic compound characteristics of the coating are beneficial to environmental protection and indoor air quality; in terms of physical properties, adhesion, weather resistance, hardness and acid and alkali resistance all meet the qualified standards, showing the stability and durability of the coating in complex environments; in addition, the viscosity, leveling and glossiness of the coating also meet the requirements of relevant standards, ensuring the smoothness of the construction process and the beauty of the coating surface.

[0050] In summary, the water-based coatings for color aluminum plates prepared in Example 1, Example 2 and Example 3 all showed excellent performance in various performance tests, met the predetermined qualification standards, and were suitable for use as surface coating materials for color aluminum plates.

[0051] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A water-based paint for color aluminum plate, It is characterized in that The invention is composed of the following raw materials in parts by weight: 40-45 parts of aqueous acrylic emulsion, 10-15 parts of aqueous epoxy resin, 15-20 parts of aqueous isocyanate, 1-3 parts of MOF material, 12-18 parts of rutile titanium dioxide, 2-3 parts of cosolvent, 1-3 parts of dispersant, 0.1-0.2 parts of neutralizer, 0.2-0.4 parts of defoamer, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of substrate wetting agent, 0.5-1.0 parts of thickener and 10-15 parts of deionized water.

2. A water-based paint for color aluminum plate according to claim 1, It is characterized in that The co-solvent is one or a combination of propylene glycol butyl ether and propylene glycol methyl ether, and the total amount is 2-3 parts by weight.

3. A water-based paint for color aluminum plate according to claim 1, It is characterized in that The dispersant is a polymer dispersant, including sodium polyacrylate or polyvinyl alcohol; and the neutralizer is an amine neutralizer.

4. A water-based paint for color aluminum plate according to claim 1, It is characterized in that The leveling agent is a fluorocarbon modified siloxane leveling agent.

5. The water-based paint for color aluminum plate according to claim 1, It is characterized in that The thickener is a compound system of hydroxyethyl cellulose and polyurethane thickener, and the amount thereof is adjusted according to the required viscosity.

6. The preparation process of a water-based paint for color aluminum plate according to claim 1, It is characterized in that The method comprises the following steps: Step 1: Resin mixing: preparing the pretreated MOF material into a nano-scale dispersion by ultrasonic dispersion or ball milling; in a preparation pot, uniformly mixing an aqueous acrylic emulsion, an aqueous epoxy resin and an aqueous isocyanate, and slowly adding the pretreated MOF material dispersion under stirring to obtain a resin mixture at a stirring speed of 150-300 r / min; Step 2: Pigment pre-dispersion: add half of the deionized water, dispersant and rutile titanium dioxide into another container, stir and mix evenly, and then grind into a sand mill to obtain a pigment slurry; Step 3: Mix and blend: Slowly add the pigment slurry into the resin mixture and stir at a speed of 500-600r / min to ensure that the pigment is evenly dispersed; Step 4: Adding additives: Under stirring, add the cosolvent, neutralizer, and remaining deionized water in sequence, increase the stirring speed to 900-1000r / min, and continue stirring for 10-15 minutes. Subsequently, add the defoamer, leveling agent, and substrate wetting agent in succession, increase the stirring speed to 1200-1500r / min, and stir for 10-15 minutes to obtain the coating base material; Step 5: Viscosity and pH adjustment: Add thickener to the coating base, stir at 1000-1200r / min for 15-25 minutes, measure with Stormer viscometer, adjust viscosity to 90-110KU, and adjust pH to 8.0-8.5 with sodium bicarbonate or other pH adjuster; Step 6: Filtration and packaging: Use a 200-400 mesh filter to filter the paint base material to remove impurities, obtain water-based paint for colored aluminum plates, and finally package it in a sealed container.

7. The preparation process of a water-based paint for color aluminum plate according to claim 6, It is characterized in that In step one, the pretreatment is to use a silane coupling agent to perform surface treatment on the MOF material.

8. The preparation process of a water-based coating for color aluminum plate according to claim 6, It is characterized in that In step 2, the resin mixing process is performed under vacuum conditions.

9. The preparation process of a water-based paint for color aluminum plate according to claim 6, It is characterized in that In step three, ultrasonic dispersion technology is used to assist the addition of the pigment slurry, that is, while the pigment slurry is slowly added to the resin mixture, an ultrasonic generator is used to perform ultrasonic treatment on the mixture, and the frequency of the ultrasonic wave is set to 20-40kHz.

10. The preparation process of a water-based paint for color aluminum plate according to claim 6, It is characterized in that In step 4, an environmentally friendly solvent is introduced to replace the co-solvent. The environmentally friendly solvent includes acetates and lactates.

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