Water-based two-component polyurethane coating as well as preparation method and application thereof

Abstract

The invention provides a water-based two-component polyurethane coating as well as a preparation method and application thereof, and belongs to the technical field of coatings. The water-based two-component polyurethane coating provided by the invention comprises a main agent and a curing agent which are subpackaged, the main agent comprises the following components in parts by mass; 60 to 80 parts of water-based hydroxypropyl resin; 1 to 5 parts of an effect pigment, wherein the effect pigment is T80-406 and / or T80-234; 0.1 to 0.3 part of a defoaming agent; 0.2 to 0.5 part of a dispersant; 5-15 parts of a cosolvent; 0.3 to 0.6 part of a wetting agent; 0.2 to 0.5 part of a thickening agent; 0.1 to 0.4 part of a pH value regulator; and 10-20 parts of water. According to the water-based two-component polyurethane coating provided by the invention, the effect pigment is adopted in the main agent, and the water-based two-component polyurethane coating is applied to the surface of a glass panel in a photovoltaic module, so that the water-based two-component polyurethane coating has relatively high light transmittance while having a relatively good color effect, thereby being beneficial to keeping relatively high photoelectric conversion efficiency of the photovoltaic module.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a water-based two-component polyurethane coating and a preparation method and application thereof. Background Art

[0002] At present, the global demand for renewable energy is increasing, bringing a broader market space for the photovoltaic power generation industry. Photovoltaic modules are the core part of the photovoltaic power generation system, which is mainly composed of glass panels, encapsulation films, cells and back panels. The glass panel is located at the outermost layer of the photovoltaic module, which plays a role in protecting the internal structure and transmitting light. However, the glass panels of traditional photovoltaic modules are usually single colors, such as blue or black, which to a certain extent limits the appearance design and application scenarios of photovoltaic modules. In order to meet the needs of different application fields and designs, photovoltaic module glass panels need a richer color selection so that they can coordinate with the surrounding environment to enhance the aesthetics. However, the color change of the glass panel cannot affect the transmittance, so as to ensure that the photovoltaic module has a high photoelectric conversion efficiency. At the same time, it needs to have good weather resistance to ensure that the color of the glass panel is not easy to fade when used outdoors for a long time, and the performance is stable and reliable.

[0003] In order to solve the above problems, the relevant technologies mainly change the appearance color of photovoltaic modules by changing the manufacturing process of the cells or applying different colors of paint on the surface of the photovoltaic modules. Among them, the former can change the appearance color of the photovoltaic modules by changing the manufacturing process of the cells, so as to make them emit different colors of light, but this method is costly and not conducive to popularization. The latter can achieve the purpose of changing the appearance color of the photovoltaic modules by applying different colors of paint on the surface of the photovoltaic modules. The pigments used in the paints of this method are usually highly transparent organic pigments, but they will still greatly reduce the light transmittance, thereby adversely affecting the power generation efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a water-based two-component polyurethane coating and a preparation method and application thereof. The water-based two-component polyurethane coating provided by the present invention is used to coat the surface of a glass panel in a photovoltaic module, and has both high light transmittance and good color effect.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a water-based two-component polyurethane coating, comprising a main agent and a curing agent which are packaged separately;

[0007] The main agent includes the following components by weight:

[0008]

[0009]

[0010] Preferably, the curing agent includes isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate.

[0011] Preferably, the mass ratio of the isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate is 3:0.5-1.5:0.5-1.5.

[0012] Preferably, the mass ratio of the main agent to the curing agent is 2.5 to 3.5:1.

[0013] Preferably, the co-solvent comprises dipropylene glycol methyl ether and dipropylene glycol butyl ether, and the mass ratio of the dipropylene glycol methyl ether to the dipropylene glycol butyl ether is 7 to 9:2.

[0014] Preferably, the aqueous hydroxypropylene resin includes aqueous hydroxypropylene resin 2766; the defoamer includes defoamer BYK-028; the dispersant includes dispersant XL 250; the wetting agent includes wetting agent 4100; the thickener includes thickener 830W; and the pH adjuster includes N,N-dimethylethanolamine.

[0015] The present invention provides a method for preparing the water-based two-component polyurethane coating according to the above technical solution, wherein the method for preparing the main agent comprises the following steps:

[0016] The components of the main agent are mixed to obtain the main agent.

[0017] The present invention provides application of the waterborne two-component polyurethane coating described in the above technical solution or the waterborne two-component polyurethane coating prepared by the preparation method described in the above technical solution in photovoltaic modules.

[0018] Preferably, the method of application comprises the following steps:

[0019] The water-based two-component polyurethane coating is diluted, and the obtained diluted coating is applied to the surface of the glass panel of the photovoltaic module to form a wet film on the surface of the glass panel, and then cured to form a cured paint film on the surface of the glass panel.

[0020] Preferably, the mass fraction of the water-based two-component polyurethane coating in the diluted coating is 85-90%; the thickness of the cured paint film is 0.01-0.1 mm; the curing temperature is 10-35° C. and the curing time is 12-24 h.

[0021] The present invention provides a water-based two-component polyurethane coating, comprising a main agent and a curing agent which are packaged separately; the main agent comprises the following components by mass: 60 to 80 parts of water-based hydroxypropyl resin; 1 to 5 parts of effect pigment, wherein the effect pigment is T80-406 and / or T80-234; 0.1 to 0.3 parts of defoamer; 0.2 to 0.5 parts of dispersant; 5 to 15 parts of cosolvent; 0.3 to 0.6 parts of wetting agent; 0.2 to 0.5 parts of thickener; 0.1 to 0.4 parts of pH value regulator; and 10 to 20 parts of water. In the water-based two-component polyurethane coating provided by the present invention, the effect pigment is used in the main agent. Compared with the traditional highly transparent organic pigment, it is used for coating on the surface of the glass panel in the photovoltaic module, and has a better color effect and a higher light transmittance, so as to help the photovoltaic module maintain a higher photoelectric conversion efficiency. DETAILED DESCRIPTION

[0022] The present invention provides a water-based two-component polyurethane coating, comprising a main agent and a curing agent which are packaged separately;

[0023] The main agent includes the following components by weight:

[0024] The main agent includes the following components by weight:

[0025]

[0026] In the related art, the purpose of changing the appearance color of photovoltaic modules can be achieved by coating different colors of coatings on the surface of photovoltaic modules, wherein the pigments used are usually highly transparent organic pigments, but the transmittance will still be greatly reduced, thereby adversely affecting the power generation efficiency. For example, in the current comparative example, a highly transparent red phase α phthalocyanine blue L6989F is used, which has high color strength, anti-flocculation and excellent fluidity. It is the most transparent phthalocyanine blue among the phthalocyanine pigments produced by Shanghai Jingyan Chemical Co., Ltd., but the light transmittance of the coating prepared by it is low. In the water-based two-component polyurethane coating provided by the present invention, effect pigments T80-406 and / or T80-234 (specifically purchased from Zhuhai Guangyu Technology Co., Ltd.) are used in the main agent, which is based on photonic crystal technology, and a photonic crystal material prepared by arranging polystyrene (PS), polymethyl methacrylate (PMMA) or silica microspheres into a periodic structure. A pre-designed three-dimensional structure is constructed by multi-layer microspheres, and a rich structural color can be regulated by controlling the forbidden band of the photonic crystal, and its structural color has strong stability, environmental protection and mechanical adjustability. Moreover, polystyrene or silicon dioxide is used as raw material, which gives the photonic crystal material excellent biosafety and environmental friendliness. The water-based two-component polyurethane coating provided by the present invention is used in photovoltaic modules, which can increase the color selection of photovoltaic modules and keep the photovoltaic modules at a high light transmittance and photoelectric conversion efficiency, and the process is simple and the cost is low. The water-based two-component polyurethane coating of the present invention is described in detail below.

[0027] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art or are prepared by methods well known to those skilled in the art.

[0028] The water-based two-component polyurethane coating of the present invention includes a main agent, which includes 60 to 80 parts of water-based hydroxypropyl resin by mass, and can be specifically 60 parts, 63 parts, 65 parts, 67 parts, 70 parts, 73 parts, 75 parts, 77 parts or 80 parts. As an embodiment of the present invention, the water-based hydroxypropyl resin can include water-based hydroxypropyl resin 2766. The present invention uses water-based hydroxypropyl resin as a matrix material, and can obtain a tough, wear-resistant, and weather-resistant cured paint film, which is conducive to ensuring the long-term use of the glass panel of the photovoltaic module.

[0029] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 1 to 5 parts of effect pigments, which can be specifically 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts. The effect pigment of the present invention is T80-406 (effect pigment blue) and / or T80-234 (effect pigment orange), which can be specifically T80-406, T80-234, or a compound of T80-406 and T80-234. The mass ratio of T80-406 to T80-234 in the compound of T80-406 and T80-234 can be 1 to 5: 1 to 5, specifically 1: 1. As an embodiment of the present invention, the particle size of the effect pigment can be 68 to 200 μm. The present invention uses the above-mentioned types and amounts of effect pigments to achieve precise control of the appearance color of photovoltaic modules, thereby meeting the needs of different customers.

[0030] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 0.1 to 0.3 parts of defoamer, specifically 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts or 0.3 parts. As an embodiment of the present invention, the defoamer may include defoamer BYK-028. The above-mentioned types and amounts of defoamers used in the embodiments of the present invention can quickly eliminate foam without residue, which is conducive to eliminating foam generated during production and application, and finally obtaining a cured paint film with excellent comprehensive performance.

[0031] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 0.2 to 0.5 parts of dispersant, specifically 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts. As an embodiment of the present invention, the dispersant may include dispersant XL 250. The above-mentioned type of dispersant is used in the embodiment of the present invention to evenly and stably disperse the effect pigment in the liquid medium, which is conducive to better dispersion of the effect pigment and makes the color distribution of the appearance of the photovoltaic module more uniform.

[0032] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 5 to 15 parts of cosolvent, specifically 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts. As an embodiment of the present invention, the cosolvent may include dipropylene glycol methyl ether (DPM) and dipropylene glycol butyl ether (DPNB), and the mass ratio of dipropylene glycol methyl ether and dipropylene glycol butyl ether may be 7 to 9:2, specifically 8:2. The use of the above-mentioned type and amount of cosolvent in the embodiment of the present invention can make the water-based two-component polyurethane coating better film-forming, which is conducive to ensuring that the water-based two-component polyurethane coating can also smoothly form a film under lower temperature conditions.

[0033] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 0.3 to 0.6 parts of a wetting agent, specifically 0.3 parts, 0.4 parts, 0.5 parts or 0.6 parts. As an embodiment of the present invention, the wetting agent may include a wetting agent 4100. The use of the above-mentioned types and amounts of wetting agents in the embodiments of the present invention can effectively reduce the surface tension of the water-based two-component polyurethane coating, enhance the wetting of the substrate, and help ensure that the water-based two-component polyurethane coating has no film defects such as shrinkage cavities and pinholes when the film is formed.

[0034] Based on the mass fraction of the water-based hydroxypropyl resin, the main agent of the present invention includes 0.2 to 0.5 parts of thickener, specifically 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts. As an embodiment of the present invention, the thickener may include thickener 830W. The use of the above-mentioned types and amounts of thickeners in the embodiments of the present invention can effectively increase the viscosity of the water-based two-component polyurethane coating, prevent sedimentation, and is beneficial to the stability of the water-based two-component polyurethane coating during storage and construction.

[0035] Based on the mass fraction of the aqueous hydroxypropyl resin, the main agent of the present invention includes 0.1 to 0.4 parts of a pH regulator, specifically 0.1, 0.2, 0.3 or 0.4 parts. As an embodiment of the present invention, the pH regulator may include N, N-dimethylethanolamine (DMEA). In the embodiment of the present invention, the pH regulator of the above type and amount can be used to make the pH value of the main agent 7 to 9, specifically 7, 7.8, 8, 8.5 or 9.

[0036] Based on the mass fraction of the aqueous hydroxypropyl resin, the main agent of the present invention includes 10 to 20 parts of water, specifically 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts. As an embodiment of the present invention, the water can be specifically deionized water.

[0037] The water-based two-component polyurethane coating of the present invention includes a curing agent packaged separately from the main agent; as an embodiment of the present invention, the mass ratio of the main agent to the curing agent can be 2.5 to 3.5:1, specifically 2.5:1, 2.8:1, 3:1, 3.2:1 or 3.5:1. As an embodiment of the present invention, the curing agent can include isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate; the mass ratio of the isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate can be 3:0.5 to 1.5:0.5 to 1.5, specifically 3:1:1. As an embodiment of the present invention, the isocyanate curing agent can be specifically isocyanate curing agent 3900. The use of the above-mentioned type and amount of curing agent in the embodiment of the present invention can effectively improve the chemical resistance and weather resistance of the cured paint film, has excellent light retention and excellent mechanical properties, and is conducive to ensuring the long-term use of the cured paint film outdoors.

[0038] The present invention provides a method for preparing the water-based two-component polyurethane coating according to the above technical solution, wherein the method for preparing the main agent comprises the following steps: mixing the components of the main agent to obtain the main agent.

[0039] As an embodiment of the present invention, specifically, a defoamer, a part of the cosolvent, water and a pH adjuster are sequentially added to the aqueous hydroxypropyl resin under stirring (for example, the stirring rate can be 400 rpm), and each component is stirred and mixed for 2 to 3 minutes after adding each component, and then the next component is added until the pH adjuster is added and stirred and mixed for 2 to 3 minutes to obtain a first mixture; the stirring rate is increased (for example, the stirring rate can be 600 rpm), a thickener is added to the first mixture and stirred and mixed for 20 to 25 minutes, and then the stirring rate is reduced (for example, the stirring rate can be 400 rpm), a wetting agent is added and stirred and mixed for 10 to 15 minutes to obtain a second mixture; the effect pigment, the dispersant and the remaining cosolvent are mixed to obtain an effect pigment slurry; the effect pigment slurry is added to the second mixture under stirring (for example, the stirring rate can be 400 rpm) and stirred and mixed for 30 to 35 minutes to obtain the main agent. As an embodiment of the present invention, the partial co-solvent is specifically a partial co-solvent DPM and the whole co-solvent DPNB; the remaining co-solvent is specifically the remaining co-solvent DPM; the mass of the partial co-solvent DPM can be 50-70% of the total mass of the co-solvent DPM, further can be 60-65%, specifically can be 62.5%.

[0040] As an embodiment of the present invention, the preparation method of the curing agent may include the following steps: mixing the components of the curing agent to obtain the curing agent. As an embodiment of the present invention, specifically, under anhydrous and stirring conditions (for example, the stirring rate may be 400 rpm), the isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate are stirred and mixed for 10 to 15 minutes to obtain the curing agent.

[0041] The present invention provides application of the waterborne two-component polyurethane coating described in the above technical solution or the waterborne two-component polyurethane coating prepared by the preparation method described in the above technical solution in photovoltaic modules.

[0042] As an embodiment of the present invention, the photovoltaic module includes a glass panel, an encapsulation film, a battery cell and a backplane; the present invention specifically applies the water-based two-component polyurethane coating to the surface of the glass panel. As an embodiment of the present invention, the method for applying the water-based two-component polyurethane coating may include the following steps: diluting the water-based two-component polyurethane coating, applying the obtained diluted coating to the surface of the glass panel of the photovoltaic module, forming a wet film on the surface of the glass panel, and then curing to form a cured paint film on the surface of the glass panel. As an embodiment of the present invention, the diluent used for the dilution may be water, specifically deionized water; the mass fraction of the water-based two-component polyurethane coating in the diluted coating may be 85-90%, specifically 87%; the coating method may be spraying; the thickness of the cured paint film may be 0.01-0.1 mm, further 0.03-0.08 mm, specifically 0.05 mm; the curing temperature may be 10-35°C, specifically room temperature, and the time may be 12-24 hours, specifically 20-24 hours.

[0043] In the embodiment of the present invention, when the water-based two-component polyurethane coating is used, it can be directly sprayed on the glass panel surface of the photovoltaic module. Since the water-based two-component polyurethane coating is a water-based coating, it will not cause pollution to the environment during the spraying process, which meets the requirements of environmental protection; after the wet film is completely cured, the change of the appearance color of the photovoltaic module can be achieved, and a photovoltaic module with an ideal appearance color can be obtained without affecting the light transmittance and photoelectric conversion efficiency of the photovoltaic module, meeting the needs of different customers for the diversified appearance color of the photovoltaic module, and the process is simple, the cost is low, and it can be widely used in the fields of photovoltaic power generation equipment manufacturing, architectural decoration design, and environmental protection material research and development. Specifically, for the field of photovoltaic power generation equipment manufacturing, the present invention can provide photovoltaic modules with more color options, meet the needs of different customers, and improve the market competitiveness of products; for the field of architectural decoration design, the present invention can design a photovoltaic module that matches the overall style and needs of the building, improve the overall aesthetics of the building, and achieve the perfect combination of photovoltaic power generation and architectural decoration; for the field of environmental protection material research and development, the effect pigments and water-based hydroxypropyl resins used in the present invention are both environmental protection materials, which meet the current social needs for environmental protection and have broad market prospects.

[0044] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The sources of raw materials involved in the following examples and comparative examples are as follows:

[0046] Table 1 Sources of raw materials involved in the examples and comparative examples

[0047]

[0048]

[0049] Examples 1 to 7

[0050] Add defoamer BYK-028, part of the cosolvent DPM (accounting for 62.5% of the total mass of the cosolvent DPM), cosolvent DPNB, deionized water and pH regulator DMEA to the aqueous hydroxypropyl resin 2766 in sequence at a stirring rate of 400 rpm, stir and mix for 2 minutes after each addition of a raw material, and then add the next raw material until the pH regulator DMEA is added and stirred for 2 minutes to obtain a first mixture; add thickener 830W to the first mixture at a stirring rate of 600 rpm and stir and mix for 20 minutes, then adjust the stirring rate to 400 rpm, add wetting agent 4100 and stir and mix for 10 minutes to obtain a second mixture; mix effect pigment (specifically effect pigment blue and / or effect pigment orange), dispersant XL250 and the remaining cosolvent DPM to obtain effect pigment slurry; add the effect pigment slurry to the second mixture at a stirring rate of 400 rpm and stir and mix for 30 minutes to obtain a main agent (the specific formula is shown in Table 2);

[0051] In anhydrous conditions with a stirring rate of 400 rpm, isocyanate curing agent 3900, propylene glycol diacetate (PGDA) and propylene glycol methyl ether acetate (PMA) were stirred and mixed at a mass ratio of 3:1:1 for 10 min to obtain a curing agent;

[0052] The main agent and the curing agent are mixed in a mass ratio of 3:1 to obtain a water-based two-component polyurethane coating.

[0053] Table 2 Main agent formula of water-based two-component polyurethane coating in Examples 1 to 7

[0054]

[0055]

[0056] Comparative Examples 1 to 4

[0057] Under the condition of stirring rate of 400 rpm, part of defoamer BYK-028, cosolvent DPM, cosolvent DPNB, part of deionized water and pH regulator DMEA were added to water-based hydroxypropyl resin 2766 in sequence. After adding each raw material, the mixture was stirred and mixed for 2 minutes before adding the next raw material. After the pH regulator DMEA was added, the mixture was stirred and mixed for 2 minutes to obtain a first mixture. Under the condition of stirring rate of 600 rpm, thickener 830W was added to the first mixture and stirred and mixed for 20 minutes. Then adjust the stirring rate to 400rpm, add the wetting agent 4100 and stir and mix for 10min to obtain a second mixture; grind and mix the high transparent red phase α phthalocyanine blue L6989F, the dispersant BYK-190, the remaining defoamer and the remaining water in a mass ratio of 0.9:0.58:0.02:0.5 to obtain a transparent organic pigment slurry; add the transparent organic pigment slurry to the second mixture at a stirring rate of 400rpm and stir and mix for 30min to obtain a main agent (the specific formula is shown in Table 3);

[0058] In anhydrous conditions with a stirring rate of 400 rpm, isocyanate curing agent 3900, propylene glycol diacetate (PGDA) and propylene glycol methyl ether acetate (PMA) were stirred and mixed at a mass ratio of 3:1:1 for 10 min to obtain a curing agent;

[0059] The main agent and the curing agent are mixed in a mass ratio of 3:1 to obtain a water-based two-component polyurethane coating.

[0060] Table 3 Main agent formula of water-based two-component polyurethane coating in comparative examples 1 to 4

[0061]

[0062] Test Example 1

[0063] The water-based two-component polyurethane coatings prepared in each embodiment and comparative example were diluted with deionized water to obtain diluted coatings; wherein the mass of the deionized water was 13% of the mass of the water-based two-component polyurethane coating; the diluted coatings were sprayed on the surface of the glass panel using a spray gun to form a wet film, and then placed at room temperature for 24 hours to completely cure the wet film, forming a cured paint film (thickness of 0.05 mm) on the surface of the glass panel, and a test sample was obtained, and performance tests were performed, as follows:

[0064] 1. Refractive index: The sample to be tested is cured at a temperature of 23±2°C and a relative humidity of 50±5% for 7 days (i.e., the wet film is cured after it is completely cured), and then the refractive index is tested using an ellipsometer.

[0065] 2. Light transmittance: The sample to be tested is cured at a temperature of 23±2°C and a relative humidity of 50±5% for 7 days (i.e., curing is performed after the wet film is completely cured), and then the light transmittance is tested using a spectrophotometer.

[0066] 3. Color effect: Place the sample to be tested (i.e., the wet film is tested directly after it is completely cured without curing) under the D65 light source of a standard light box to compare the color effect.

[0067] 4. Artificial weathering aging test (UV lamp, 2000h): The test sample is cured for 7 days at a temperature of 23±2°C and a relative humidity of 50±5% (i.e., the wet film is cured after it is completely cured), and then the artificial weathering aging test is carried out using a UV weathering test chamber.

[0068] The test instruments used in this test example are shown in Table 4, and the test results are shown in Table 5. As can be seen from Table 5, the waterborne two-component polyurethane coatings prepared in Example 2, Example 5 and Example 7 have better performance, that is, when the amount of effect pigment added accounts for 3% of the mass of the main agent, they have both a suitable refractive index and a high light transmittance, and a good color effect, while the waterborne two-component polyurethane coating prepared in the comparative example has a low light transmittance.

[0069] Table 4 Test instruments

[0070]

[0071] Table 5 Performance test results

[0072]

[0073]

[0074] It can be seen from the above results that, compared with the prior art, the water-based two-component polyurethane coating provided by the present invention has at least the following beneficial effects:

[0075] 1. No influence on photoelectric conversion efficiency: The present invention adds effect pigments into water-based two-component polyurethane coatings and sprays them on the surface of glass panels. This method does not affect the light transmittance of photovoltaic modules, thereby ensuring the photoelectric conversion efficiency of photovoltaic modules and solving the problem of reducing the light transmittance of photovoltaic modules in the prior art.

[0076] 2. Simplify the production process and reduce costs: The present invention does not need to change the manufacturing process of the battery cell. When preparing the water-based two-component polyurethane coating, there is no need to grind the color paste. It only needs to wet and disperse the effect pigment evenly and directly mix it with other components. The operation method is simple and easy, which can greatly reduce the production cost and solve the problem that the prior art may require complex processes and high costs.

[0077] 3. Improve the aesthetics of buildings: The present invention can create an ideal surface effect according to customer needs, so that the photovoltaic modules not only have the function of power generation, but also have the function of decoration, thereby improving the overall aesthetics of the building.

[0078] The above is only 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A water-based two-component polyurethane coating, characterized in that: Including the main agent and curing agent packaged separately; The main agent includes the following components by weight:

2. The water-based two-component polyurethane coating according to claim 1, characterized in that: The curing agent includes isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate.

3. The water-based two-component polyurethane coating according to claim 2, characterized in that: The mass ratio of the isocyanate curing agent, propylene glycol diacetate and propylene glycol methyl ether acetate is 3:0.5-1.5:0.5-1.

5.

4. The water-based two-component polyurethane coating according to any one of claims 1 to 3, characterized in that: The mass ratio of the main agent to the curing agent is 2.5 to 3.5:

1.

5. The water-based two-component polyurethane coating according to claim 1, characterized in that: The co-solvent comprises dipropylene glycol methyl ether and dipropylene glycol butyl ether, and the mass ratio of the dipropylene glycol methyl ether to the dipropylene glycol butyl ether is 7 to 9:

2.

6. The water-based two-component polyurethane coating according to claim 1, characterized in that: The water-based hydroxypropylene resin includes water-based hydroxypropylene resin 2766; the defoamer includes defoamer BYK-028; the dispersant includes dispersant XL 250; the wetting agent includes wetting agent 4100; the thickener includes thickener 830W; and the pH adjuster includes N,N-dimethylethanolamine.

7. The method for preparing the waterborne two-component polyurethane coating according to any one of claims 1 to 6, characterized in that: The preparation method of the main agent comprises the following steps: The components of the main agent are mixed to obtain the main agent.

8. Use of the waterborne two-component polyurethane coating according to any one of claims 1 to 6 or the waterborne two-component polyurethane coating prepared by the preparation method according to claim 7 in photovoltaic modules.

9. The use according to claim 8, characterized in that: The method of application comprises the following steps: The water-based two-component polyurethane coating is diluted, and the obtained diluted coating is applied to the surface of the glass panel of the photovoltaic module to form a wet film on the surface of the glass panel, and then cured to form a cured paint film on the surface of the glass panel.

10. The use according to claim 9, characterized in that: The mass fraction of the water-based two-component polyurethane coating in the diluted coating is 85-90%; the thickness of the cured paint film is 0.01-0.1 mm; the curing temperature is 10-35° C. and the curing time is 12-24 hours.

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