Preparation method of anti-ultraviolet weather-resistant water-based paint

Abstract

The invention provides a preparation method of an anti-ultraviolet weather-resistant water-based coating, and belongs to the technical field of coatings. The preparation method comprises the following steps: (1) weighing the following components in parts by weight: 18-23 parts of acrylic resin, 30-35 parts of polyurethane resin, 10-15 parts of hydroxy acrylic resin, 6-10 parts of modified filler, 23-28 parts of deionized water, 1-2 parts of a defoaming agent, 2-3 parts of a coalescing agent, 2-3 parts of a thickening agent and 1-2 parts of a flatting agent; and (2) uniformly mixing the acrylic resin, the polyurethane resin, the hydroxy acrylic resin and the deionized water, and adding the rest components while stirring for 30-40 minutes to obtain the anti-ultraviolet weather-resistant water-based paint. When being applied to waterproofing of buildings, the water-based paint has good heat resistance and aging resistance, still has high bonding strength with a base material after being soaked in water, and is good in storage stability.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and particularly relates to a method for preparing an anti-ultraviolet and weather-resistant water-based coating. Background Art

[0002] Waterproof coatings for buildings are specialized coatings used to prevent water from penetrating into buildings. They are typically applied to moisture-prone areas such as roofs, basements, bathrooms, and kitchens. Currently, commonly used water-based waterproof coatings for buildings are primarily acrylic or ethylene-vinyl acetate emulsions, combined with cement and fillers to form polymer cement waterproof coatings (JS waterproof coatings for short).

[0003] When coatings are used in outdoor buildings, the following problems may be encountered. These problems are mainly related to the selection of coatings, construction conditions, environmental factors and maintenance. Specifically, they are: (1) Changes in external temperature cause the coating to crack and peel; (2) Poor storage stability: One-component polyurethane waterproof coatings gradually thicken and clump when placed outdoors in the summer; (3) Two-component polyurethane and one-component polyurethane coatings take a long time to dry or do not dry after construction.

[0004] To address the temperature resistance issues of water-based coatings, existing technologies typically add heat stabilizers to water-based coatings to enhance their stability at high temperatures. However, the addition of heat stabilizers deteriorates the storage stability of the coating, making it difficult to store, affecting its use and reducing its market competitiveness.

[0005] Therefore, there is an urgent need for a method for preparing an anti-ultraviolet and weather-resistant water-based coating. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing an anti-ultraviolet and weather-resistant water-based coating.

[0007] In order to achieve the above object, the present invention provides the following technical solutions: A method for preparing an anti-ultraviolet and weather-resistant water-based coating, the method comprising the following steps: (1) Weigh the following components in parts by weight: 18-23 parts of acrylic resin, 30-35 parts of polyurethane resin, 10-15 parts of hydroxy acrylic resin, 6-10 parts of modified filler, 23-28 parts of deionized water, 1-2 parts of defoaming agent, 2-3 parts of film-forming aid, 2-3 parts of thickener and 1-2 parts of leveling agent; (2) Mix the acrylic resin, polyurethane resin, hydroxy acrylic resin and deionized water evenly, add the remaining components while stirring for 30-40 minutes to obtain an anti-UV and weather-resistant water-based coating.

[0008] Furthermore, the carboxylated double-walled carbon nanotubes have a diameter of 2-4 nm, a length of 0.5-2 μm, and a carboxyl content of 2.58 wt %, and were purchased from Xianfeng Nano, item number 100227.

[0009] Furthermore, the carboxylated graphene oxide sheet has a diameter of 0.5-5 microns and a thickness of 0.8-1.2 nm and was purchased from Xianfeng Nano, item number: 100009.

[0010] Furthermore, the average size of the carboxylated silica is 20 nm and was purchased from Xianfeng Nano, product number: 103113.

[0011] Furthermore, the preparation method of the polyurethane resin includes the following steps: weighing 3-4 parts by mass of diisocyanate, 1-2 parts by mass of polyethylene glycol 300, and 8-10 parts by mass of butanone, mixing them evenly, heating them to 62-67° C., keeping the temperature for 3-4 hours, continuously adding 4-5 parts by mass of polyether polyol and 0.4-0.7 parts by mass of stannous octoate, reflux reacting at 82-86° C. for 4-5 hours, cooling them to 40-45° C., continuously adding 2-3 parts by mass of 1,4-butanediol, 1-1.5 parts by mass of triethylamine and 4-5 parts by mass of deionized water, mixing them evenly, heating them to 72-76° C., keeping the temperature for 5-6 hours, and cooling them to room temperature to obtain the polyurethane resin.

[0012] Furthermore, the polyether polyol is a mixture of a polyether triol with a hydroxyl number of 535 mgKOH / g, a polyether diol with a hydroxyl number of 36-39 mgKOH / g, and a polyether diol with a hydroxyl number of 153-188 mgKOH / g in a mass ratio of (0.3-0.6): (1.2-1.4): 1.

[0013] Furthermore, the diisocyanate is selected from one or more of isophorone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0014] Furthermore, the acrylic resin has a solid content of 40±1 wt % and a viscosity of 500-900 mPa·s at 25° C. It was purchased from Guangdong Xidun New Material Technology Co., Ltd., model: SEACRYL11P27.

[0015] Currently, commercially available water-based paints mainly include four types: water-based inorganic zinc-rich paints, water-based epoxy paints, water-based acrylic paints, and water-based polyurethane paints, and their heat resistance cannot meet the needs of consumers. The present invention attempts to mix polyurethane resins and acrylic resins to improve the bonding strength of the paint, but the effect is not ideal. The present invention can improve the bonding strength of water-based paints after heat treatment by preparing a specific polyurethane resin and mixing it with an acrylic resin. The polyurethane resin and acrylic resin prepared by the present invention can produce a synergistic effect after mixing, and the two resins are intertwined to form a more complex and stable coating. The polyurethane resin prepared by the present invention has good flexibility and elasticity, which helps the paint to maintain its shape and not crack easily when the temperature changes. The flexibility of the polyurethane resin and the weather resistance of the acrylic resin are combined, so that the mixed paint can maintain good bonding strength after heat treatment. However, the bonding strength of the water-based paint after immersion treatment is not ideal.

[0016] Furthermore, the hydroxylated acrylic resin comprises hydroxylated acrylic resin A, hydroxylated acrylic resin B, and hydroxylated acrylic resin C in a weight ratio of 1:(1.3-1.5):(0.2-0.5). Hydroxylated acrylic resin A has a solid content of 40 wt% and a hydroxyl value of 12 KOH mg / g, and is a Japanese Mitsubishi acrylic resin LR-7779. Hydroxylated acrylic resin B has a solid content of 48-52 wt% and a hydroxyl value of 25-30 KOH mg / g, and is a Japanese Mitsui OLESTER Q850. Hydroxylated acrylic resin B has a solid content of 50±1.5 wt% and a hydroxyl value of 75±5 KOH mg / g, and is a Japanese Mitsui Chemicals OLESTER Q519 hydroxylated acrylic resin.

[0017] The present invention improves the bonding strength of a water-based coating after immersion treatment by adding a hydroxylated acrylic resin to the water-based coating. This is because the addition of the hydroxylated acrylic resin can form a denser network structure with the polyurethane resin and the acrylic resin, while also forming a dense protective film on the substrate surface, maintaining good adhesion in a humid environment, thereby improving the performance of the water-based coating in practical applications. Furthermore, when the hydroxylated acrylic resin is a mixture of hydroxylated acrylic resin A, hydroxylated acrylic resin B, and hydroxylated acrylic resin C in a specific ratio, the temperature change resistance of the water-based coating can be improved.

[0018] Furthermore, the modified filler is prepared by modifying carboxylated double-walled carbon nanotubes, carboxylated graphene oxide and carboxylated silicon dioxide using 3-isocyanatepropyltrimethoxysilane.

[0019] Furthermore, the defoaming agent includes at least one of sodium hexametaphosphate, potassium tripolyphosphate, and potassium pyrophosphate.

[0020] Furthermore, the film-forming aid includes at least one of polyethylene glycol 200, polyethylene glycol 300, and polyethylene glycol 400.

[0021] Furthermore, the thickener is a solvent-free polyurethane thickener, Coatex polyurethane thickener from France, model CoapurXS83.

[0022] Furthermore, the leveling agent is a polyurethane rheology modifier. Beijing Dongfang Chennuo Chemical Technology Co., Ltd., model CN-2020.

[0023] Compared with the prior art, the advantages and beneficial effects of the present invention are: 1. When the water-based paint of the present invention is used for building waterproofing, it has good heat resistance and aging resistance, and still has a high bonding strength with the substrate after immersion in water.

[0024] 2. The present invention can improve the bonding strength of water-based coatings after heat treatment by preparing a mixture of specific polyurethane resin and acrylic resin.

[0025] 3. By adding hydroxy acrylic resin to water-based paint, the bonding strength of the water-based paint after immersion treatment can be improved. At the same time, when the hydroxy acrylic resin is a mixture of hydroxy acrylic resin A, hydroxy acrylic resin B and hydroxy acrylic resin C in a specific ratio, the temperature change resistance of the water-based paint can be improved. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] Example 1 This embodiment provides a method for preparing an anti-ultraviolet and weather-resistant water-based coating, the preparation method comprising the following steps: (1) Preparation of modified fillers: The preparation method of the modified filler comprises the following steps: S1: Carboxylated double-walled carbon nanotubes, carboxylated graphene oxide, and carboxylated silica in a mass ratio of 0.4:1:1.5 were mixed to obtain a filler. Under a nitrogen atmosphere, 1 mass part of 3-isocyanatepropyltrimethoxysilane and 0.14 mass part of the filler were mixed, and the mixture was ultrasonicated for 23 minutes. 62 mass parts of N,N-dimethylformamide were added, and the mixture was stirred at 80°C for 2.5 hours and centrifuged. The centrifuged precipitate was freeze-dried to obtain a modified filler.

[0028] The carboxylated double-walled carbon nanotubes have a diameter of 2-4 nm, a length of 0.5-2 μm, and a carboxyl content of 2.58 wt %. They were purchased from Xianfeng Nanotechnology, item number 100227.

[0029] Carboxylated graphene oxide sheets with a diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm were purchased from Xianfeng Nano, catalog number 100009.

[0030] The average size of carboxylated silica was 20 nm and was purchased from Xianfeng Nano, product number: 103113.

[0031] (2) Weigh the following components in parts by weight: 20 parts of acrylic resin, 33 parts of polyurethane resin, 12 parts of hydroxy acrylic resin, 8 parts of modified filler, 25 parts of deionized water, 1.4 parts of defoaming agent, 2.2 parts of film-forming aid, 2.6 parts of thickener and 1.7 parts of leveling agent; (3) Mix the acrylic resin, polyurethane resin, hydroxy acrylic resin and deionized water evenly, add the remaining components while stirring for 35 minutes to obtain an anti-UV and weather-resistant water-based coating.

[0032] The preparation method of the polyurethane resin comprises the following steps: weighing 3.5 parts by mass of diisocyanate, 1.2 parts by mass of polyethylene glycol 300, and 9 parts by mass of butanone, mixing them uniformly, heating them to 65° C., keeping the temperature for 3.5 hours, continuously adding 4.6 parts by mass of polyether polyol and 0.5 parts by mass of stannous octoate, carrying out reflux reaction at 84° C. for 4.6 hours, cooling them to 42° C., continuously adding 2.7 parts by mass of 1,4-butanediol, 1.2 parts by mass of triethylamine, and 4.8 parts by mass of deionized water, mixing them uniformly, heating them to 75° C., keeping the temperature for 5.5 hours, and cooling them to room temperature to obtain the polyurethane resin.

[0033] The polyether polyol is a mixture of a polyether triol with a hydroxyl number of 535 mgKOH / g, a polyether diol with a hydroxyl number of 36-39 mgKOH / g, and a polyether diol with a hydroxyl number of 153-188 mgKOH / g in a mass ratio of 0.5:1.3:1. The diisocyanate is 1,6-hexamethylene diisocyanate.

[0034] The acrylic resin had a solid content of 40±1 wt % and a viscosity of 500-900 mPa·s at 25° C. It was purchased from Guangdong Xidun New Material Technology Co., Ltd., model: SEACRYL11P27.

[0035] The hydroxylated acrylic resin includes hydroxylated acrylic resin A, hydroxylated acrylic resin B, and hydroxylated acrylic resin C in a weight ratio of 1:1.4:0.4. Hydroxylated acrylic resin A has a solid content of 40 wt% and a hydroxyl value of 12 KOH mg / g, and is a Mitsubishi acrylic resin LR-7779 from Japan. Hydroxylated acrylic resin B has a solid content of 48-52 wt% and a hydroxyl value of 25-30 KOH mg / g, and is a Mitsui Chemicals OLESTER Q850 from Japan. Hydroxylated acrylic resin B has a solid content of 50 ± 1.5 wt% and a hydroxyl value of 75 ± 5 KOH mg / g, and is a Mitsui Chemicals OLESTER Q519 hydroxylated acrylic resin from Japan.

[0036] The defoamer was sodium hexametaphosphate. The film-forming aid was polyethylene glycol 200. The thickener was a solvent-free polyurethane thickener, specifically Coatex polyurethane thickener from France, model number Coapur XS83. The leveling agent was a polyurethane rheology modifier, purchased from Beijing Dongfang Chennuo Chemical Technology Co., Ltd., model number CN-2020.

[0037] Example 2 This embodiment provides a method for preparing an anti-ultraviolet and weather-resistant water-based coating, the preparation method comprising the following steps: (1) Preparation of modified fillers: The preparation method of the modified filler comprises the following steps: S1: Carboxylated double-walled carbon nanotubes, carboxylated graphene oxide, and carboxylated silica were mixed in a mass ratio of 0.2:1:1.7 to obtain a filler. Under a nitrogen atmosphere, 1 part by mass of 3-isocyanatepropyltrimethoxysilane and 0.16 parts by mass of the filler were mixed, ultrasonicated for 25 minutes, and 60 parts by mass of N,N-dimethylformamide were added. The mixture was stirred at 80°C for 2 hours and centrifuged. The centrifuged precipitate was freeze-dried to obtain a modified filler. The carboxylated double-walled carbon nanotubes had a diameter of 2-4 nm, a length of 0.5-2 μm, and a carboxyl content of 2.58 wt%. They were purchased from Xianfeng Nano, Catalog No. 100227. The carboxylated graphene oxide had a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm. They were purchased from Xianfeng Nano, Catalog No. 100009. The average size of the carboxylated silica was 20 nm. Purchased from Xianfeng Nano, product number: 103113.

[0038] (2) Weigh the following components in parts by weight: 23 parts of acrylic resin, 30 parts of polyurethane resin, 15 parts of hydroxy acrylic resin, 6 parts of modified filler, 28 parts of deionized water, 1 part of defoamer, 3 parts of film-forming aid, 2 parts of thickener and 2 parts of leveling agent; (3) Mix the acrylic resin, polyurethane resin, hydroxy acrylic resin and deionized water evenly, add the remaining components while stirring for 30 minutes to obtain an anti-UV and weather-resistant water-based coating.

[0039] The preparation method of the polyurethane resin comprises the following steps: weighing 4 parts by mass of diisocyanate, 1 part by mass of polyethylene glycol 300, and 8 parts by mass of butanone, mixing them uniformly, heating them to 67°C, keeping the temperature for 3 hours, continuously adding 5 parts by mass of polyether polyol and 0.4 parts by mass of stannous octoate, carrying out reflux reaction at 86°C for 5 hours, cooling them to 40°C, continuously adding 3 parts by mass of 1,4-butanediol, 1 part by mass of triethylamine, and 5 parts by mass of deionized water, mixing them uniformly, heating them to 72°C, keeping the temperature for 6 hours, and cooling them to room temperature to obtain the polyurethane resin.

[0040] The polyether polyol is a mixture of a polyether triol with a hydroxyl number of 535 mgKOH / g, a polyether diol with a hydroxyl number of 36-39 mgKOH / g, and a polyether diol with a hydroxyl number of 153-188 mgKOH / g in a mass ratio of 0.3:1.4:1. The diisocyanate is 1,6-hexamethylene diisocyanate.

[0041] The acrylic resin had a solid content of 40±1 wt % and a viscosity of 500-900 mPa·s at 25° C. It was purchased from Guangdong Xidun New Material Technology Co., Ltd., model: SEACRYL11P27.

[0042] The hydroxylated acrylic resin includes hydroxylated acrylic resin A, hydroxylated acrylic resin B, and hydroxylated acrylic resin C in a weight ratio of 1:1.3:0.5. Hydroxylated acrylic resin A has a solid content of 40 wt% and a hydroxyl value of 12 KOH mg / g, and is a Mitsubishi acrylic resin LR-7779 from Japan. Hydroxylated acrylic resin B has a solid content of 48-52 wt% and a hydroxyl value of 25-30 KOH mg / g, and is a Mitsui Chemicals OLESTER Q850 from Japan. Hydroxylated acrylic resin B has a solid content of 50 ± 1.5 wt% and a hydroxyl value of 75 ± 5 KOH mg / g, and is a Mitsui Chemicals OLESTER Q519 hydroxylated acrylic resin from Japan.

[0043] The defoamer was sodium hexametaphosphate. The film-forming aid was polyethylene glycol 200. The thickener was a solvent-free polyurethane thickener, specifically Coatex polyurethane thickener from France, model number Coapur XS83. The leveling agent was a polyurethane rheology modifier, purchased from Beijing Dongfang Chennuo Chemical Technology Co., Ltd., model number CN-2020.

[0044] Comparative Example 1 The difference between this comparative example and Example 1 is: 25 parts of acrylic resin, 20 parts of polyurethane resin, and 20 parts of hydroxy acrylic resin.

[0045] Comparative Example 2 This comparative example differs from Example 1 in that the hydroxylated acrylic resins comprise hydroxylated acrylic resin A, hydroxylated acrylic resin B, and hydroxylated acrylic resin C in a weight ratio of 1:1:1. Hydroxylated acrylic resin A has a solid content of 40 wt % and a hydroxyl value of 12 KOH mg / g, and is a Japanese Mitsubishi acrylic resin LR-7779. Hydroxylated acrylic resin B has a solid content of 48-52 wt % and a hydroxyl value of 25-30 KOH mg / g, and is a Japanese Mitsui OLESTER Q850. Hydroxylated acrylic resin B has a solid content of 50 ± 1.5 wt % and a hydroxyl value of 75 ± 5 KOH mg / g, and is a Japanese Mitsui Chemicals OLESTER Q519 hydroxylated acrylic resin.

[0046] Comparative Example 3 The difference between this comparative example and Example 1 is that the polyether polyol is a mixture of a polyether triol having a hydroxyl number of 535 mgKOH / g, a polyether diol having a hydroxyl number of 36-39 mgKOH / g, and a polyether diol having a hydroxyl number of 153-188 mgKOH / g in a mass ratio of 1:1:1. The diisocyanate is 1,6-hexamethylene diisocyanate.

[0047] Comparative Example 4 The difference between this comparative example and Example 1 is that the solid content of the acrylic resin is 20±1%, and the viscosity at 25° C. is 300-400 mPa·s.

[0048] Comparative Example 5 The difference between this comparative example and Example 1 is that the modified filler is replaced by a filler. Carboxylated double-walled carbon nanotubes, carboxylated graphene oxide, and carboxylated silicon dioxide are mixed in a mass ratio of 1:1:1 to obtain a filler.

[0049] Comparative Example 6 This comparative example differs from Example 1 in that the carboxylated double-walled carbon nanotubes have a diameter of 10-20 nm, a length of 0.5-2 μm, and a carboxyl content of 2 wt %. They were purchased from Xianfeng Nanotechnology, item number 100262. The carboxylated silica has an average size of 100 nm, also purchased from Xianfeng Nanotechnology, item number 103114. The carboxylated graphene oxide was replaced with graphene oxide, with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm, also purchased from Xianfeng Nanotechnology, item number 100602.

[0050] Performance Testing The water-based coatings prepared in Examples 1-2 and Comparative Examples 1-6 were subjected to performance tests.

[0051] 1. Resistance to temperature change: Tested in accordance with standard JG / T25-2017.

[0052] 2. Aging resistance: Tested in accordance with standard JG / T25-2017.

[0053] 3. Bond strength after heat treatment and water immersion treatment: Test in accordance with GB / T23445-2009.

[0054] 4. Place the water-based paint in a constant temperature oven at 50±5℃ for 90 days and observe whether there is floating color, precipitation or water separation. If there is no such phenomenon, it is passed; otherwise it is recorded as failed.

[0055] The specific test results are shown in Table 1.

[0056] Table 1 Performance test results Temperature resistance Aging resistance Bond strength after heat treatment (MPa) Bond strength after water immersion treatment (MPa) stability Example 1 pass 1296h no powdering, no bubbles, no cracking 1.8 1.8 pass Example 2 pass 1284h no powdering, no bubbles, no cracking 1.7 1.7 pass Comparative Example 1 Failed 576h no powdering, no bubbles, no cracking 1.3 1.0 Failed Comparative Example 2 Failed 720h no powdering, no bubbles, no cracking 1.4 1.2 Failed Comparative Example 3 pass No powdering, no bubbles, no cracking for 624 hours 1.5 1.3 Failed Comparative Example 4 pass No powdering, no bubbles, no cracks after 600h 1.7 1.6 Failed Comparative Example 5 pass 720h no powdering, no bubbles, no cracking 1.6 1.4 Failed Comparative Example 6 pass No powdering, no bubbles, no cracking after 748 hours 1.7 1.5 Failed From the above performance test results, it can be seen that the comprehensive performance of the water-based coatings of Examples 1-2 is excellent, especially the comprehensive performance of Example 1 is the most outstanding, which is mainly due to the synergistic effect of multiple components.

[0057] The comparative examples, because they do not adopt the necessary technical solutions, cause them to be significantly worse than the embodiments in terms of corresponding performance tests. The proportions of the three resins of comparative example 1, acrylic resin, polyurethane resin and hydroxy acrylic resin are different, and the comprehensive properties of water-based paint all decline. The composition of the hydroxy acrylic resin of comparative example 2 is different, and the bonding strength and temperature resistance of the water-based paint decline after immersion treatment. The preparation method of the polyurethane resin of comparative example 3 is different, and the acrylic resin used in comparative example 4 is different, so that the bonding strength declines after the water-based paint is thermally treated. The preparation schemes of the modified fillers of comparative examples 5-6 are different, and the aging resistance of the water-based paint declines, and the stability variation of the water-based paint deteriorates. The above experimental results further demonstrate the importance of the technical solution defined in the present invention for its technical effect.

[0058] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an anti-ultraviolet and weather-resistant water-based coating, characterized in that: The preparation method comprises the following steps: (1) Weigh the following components in parts by weight: 18-23 parts of acrylic resin, 30-35 parts of polyurethane resin, 10-15 parts of hydroxy acrylic resin, 6-10 parts of modified filler, 23-28 parts of deionized water, 1-2 parts of defoaming agent, 2-3 parts of film-forming aid, 2-3 parts of thickener and 1-2 parts of leveling agent; (2) Mix the acrylic resin, polyurethane resin, hydroxy acrylic resin and deionized water evenly, add the remaining components while stirring for 30-40 minutes to obtain an anti-UV and weather-resistant water-based coating.

2. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The preparation method of the polyurethane resin comprises the following steps: weighing 3-4 parts by mass of diisocyanate, 1-2 parts by mass of polyethylene glycol 300, and 8-10 parts by mass of butanone, mixing them uniformly, heating them to 62-67° C., keeping the temperature for 3-4 hours, continuously adding 4-5 parts by mass of polyether polyol and 0.4-0.7 parts by mass of stannous octoate, carrying out reflux reaction at 82-86° C. for 4-5 hours, cooling them to 40-45° C., continuously adding 2-3 parts by mass of 1,4-butanediol, 1-1.5 parts by mass of triethylamine, and 4-5 parts by mass of deionized water, mixing them uniformly, heating them to 72-76° C., keeping the temperature for 5-6 hours, and cooling them to room temperature to obtain the polyurethane resin.

3. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 2, wherein: The polyether polyol is a mixture of a polyether triol having a hydroxyl number of 535 mgKOH / g, a polyether diol having a hydroxyl number of 36-39 mgKOH / g, and a polyether diol having a hydroxyl number of 153-188 mgKOH / g in a mass ratio of (0.3-0.6):(1.2-1.4):

1.

4. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 2, wherein: The diisocyanate is selected from one or more of isophorone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

5. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The solid content of the acrylic resin is 40±1 wt %, and the viscosity at 25° C. is 500-900 mPa·s.

6. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The hydroxyl acrylic resin includes hydroxyl acrylic resin A, hydroxyl acrylic resin B and hydroxyl acrylic resin C in a weight ratio of 1: (1.3-1.5): (0.2-0.5); the solid content of the hydroxyl acrylic resin A is 40wt%, and the hydroxyl value is 12KOHmg / g; the solid content of the hydroxyl acrylic resin B is 48-52wt%, and the hydroxyl value is 25-30KOHmg / g, and the model is Japan Mitsui OLESTERQ850; the solid content of the hydroxyl acrylic resin B is 50±1.5wt%, and the hydroxyl value is 75±5KOHmg / g.

7. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The modified filler is prepared by modifying carboxylated double-walled carbon nanotubes, carboxylated graphene oxide and carboxylated silicon dioxide using 3-isocyanate propyltrimethoxysilane.

8. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The film-forming aid includes at least one of polyethylene glycol 200, polyethylene glycol 300, and polyethylene glycol 400.

9. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The thickener is a solvent-free polyurethane thickener.

10. The method for preparing the UV-resistant and weather-resistant water-based coating according to claim 1, wherein: The leveling agent is a polyurethane rheology modifier.