A water-based coating for photovoltaic frame and a preparation method thereof

Abstract

The application provides a water-based coating for a photovoltaic frame and a preparation method thereof, and the water-based coating comprises the following raw material components in mass fractions: A component comprises 20-50 parts of a water-based fluorine-containing hydroxyl acrylic acid dispersion, 20-50 parts of a water-based hydroxyl acrylic acid dispersion, 1-3 parts of a silane oligomer, 0.5-1.5 parts of graphene, 1-5 parts of a polytetrafluoroethylene wax emulsion, 1-20 parts of a pigment, 1-8 parts of a cosolvent, 1-8 parts of an additive, and 0-15 parts of deionized water; and B component comprises 10-100 parts of a hydrophilic modified aliphatic polyisocyanate, 0-90 parts of a polyurethane grade solvent, and 1-3 parts of a dehydrating agent. The protective coating formed by the water-based coating prepared by the application can simultaneously achieve excellent wear resistance, aging resistance, wet and freeze resistance, wet and heat resistance, salt spray corrosion resistance and PCT (high pressure accelerated wet heat aging) performance, and effectively prolongs the service life of the polyurethane composite frame for photovoltaics.

Description

Technical Field

[0001] This invention relates to the field of water-based coatings technology, and in particular to a water-based coating for photovoltaic frames and its preparation method. Background Technology

[0002] In the process of realizing a circular economy, solar energy, as a renewable energy source, plays a crucial role in the current and future energy mix. The frame is a vital component of solar photovoltaic (PV) modules, serving to fix and seal the solar cells, enhance module strength, and facilitate transportation and installation. Its performance directly impacts the installation and lifespan of the modules. Historically, the vast majority of PV module frames have been made of aluminum alloy profiles. With the rapid development of the PV industry, aluminum consumption has increased year by year. The upstream material for aluminum alloy profiles is electrolytic aluminum, and the production process of electrolytic aluminum consumes a large amount of electricity, resulting in significant carbon emissions. Faced with both rapidly growing demand and limited production capacity, PV module manufacturers have been searching for higher-performance and more cost-competitive materials to replace aluminum alloys. This is not only to control material costs but also to reduce the high-energy-consuming materials needed in the process of converting solar energy into sustainable energy.

[0003] Polyurethane composite frames possess excellent material properties. Furthermore, as a non-metallic material solution, polyurethane composite frames offer advantages that metal frames lack, enabling photovoltaic module manufacturers to reduce costs and increase efficiency. Polyurethane composites exhibit superior mechanical properties, with axial tensile strength exceeding that of traditional aluminum alloys by more than seven times. They also possess strong resistance to salt spray and chemical corrosion. Non-metallic frames are an ideal alternative to aluminum alloy frames.

[0004] In recent years, the photovoltaic industry has developed rapidly, and the installation environment for photovoltaic modules has become more extreme and complex. Polyurethane composite materials possess excellent properties such as high strength, high modulus, insulation, corrosion resistance, and salt spray resistance, making them an excellent choice for photovoltaic system applications in special scenarios such as offshore photovoltaic, saline-alkali land photovoltaic, and swamp photovoltaic. At the same time, the manufacturing process of polyurethane composite materials is characterized by low carbon emissions, which coincides with the industry's demand for carbon reduction and energy conservation. To protect the frames of photovoltaic modules that are exposed to the outdoors year-round, a water-based coating for polyurethane composite photovoltaic frames has been developed. Summary of the Invention

[0005] Based on the shortcomings of the existing technology, the present invention aims to prepare a water-based coating for photovoltaic frames. The protective coating formed by using the water-based coating for photovoltaic frames has excellent weather resistance and can provide excellent and long-lasting protection for photovoltaic frames.

[0006] According to one aspect of the present invention, a water-based coating for a photovoltaic frame comprises component A and component B;

[0007] Component A comprises the following parts by weight of raw materials:

[0008]

[0009] Component B comprises the following parts by weight of raw materials:

[0010] 10-100 parts of hydrophilic modified aliphatic polyisocyanate

[0011] Polyurethane grade solvent: 0-90 parts (excluding 0)

[0012] 1-3 parts of dehydrating agent;

[0013] Where A component : B component = (3~8):1.

[0014] Furthermore, the aqueous fluorinated hydroxy acrylic dispersion is ZT-9632 from Zhitai Technology.

[0015] Furthermore, the aqueous hydroxyacrylic acid dispersion is one or both of Covestro Bayhydrol A2546 and Wanhua Chemical Antkote 2702.

[0016] Furthermore, the silane oligomer is Momentive CoatOsil MP200.

[0017] Furthermore, the graphene is element 1132.

[0018] Furthermore, the nano-silica sol is one or both of Akzo LEVASILCT20PH and Grace HS-30.

[0019] Furthermore, the polytetrafluoroethylene wax emulsion includes one or both of Nanjing Tianshi PTFE-1008 and Nanjing Tianshi PTFE1005.

[0020] Furthermore, the pigment includes one or more of carbon black, aluminum silver paste, and titanium dioxide.

[0021] Furthermore, the co-solvent includes one or more of dipropylene glycol butyl ether, dipropylene glycol methyl ether, ethylene glycol butyl ether, and diethylene glycol butyl ether.

[0022] Further, the additives include the following raw materials in parts by weight: 0-1 parts wetting agent, 0-3 parts dispersant, 0-2 parts defoamer, 0-2 parts leveling agent, 0-2 parts thickener, and 0-2 parts light stabilizer;

[0023] The wetting agent is one or more of BYK346, surfyno104BC, PE100, TEGO270, TEGO245, TEGO450 and BYK381, preferably one or more of BYK346, TEGO270 and Surfynol04BC.

[0024] The dispersant is one or more of TEGO755W, TEGO757W, BYK190, SN5040, TEGO752W, TEGO760W, TEGO750W, BYK191, BYK192, BYK194N and BYK199, preferably one or two of TEGO755W and BYK190.

[0025] The defoamer is one or more of TEGO810, TEGO902W, TEGO904W, TEGO822, TEGO825, BYK024, BYK011, BYK021 and BYK028, preferably one or more of TEGO810, TEGO904W and BYK024.

[0026] The leveling agent is one or more of TEGO410, TEGO4100, TEGoglide450, EFKA3033, BYK333 and BYK378, preferably one or two of TEGO4100 and BYK333.

[0027] The thickener is one or more of RM2020, RM8W, RM12W, Hemings 299 and OMG0620, preferably one or two of RM8W and OMG0620.

[0028] The light stabilizer is an ultraviolet absorber, including one or both of CIBA292 and CIBA1130.

[0029] Furthermore, the hydrophilic modified aliphatic polyisocyanate is one or more of Covestro Bayhydur XP2655, Covestro Bayhydur 401-70, Wanhua Chemical Aquolin 269A, and LianGu Chemical 3598T.

[0030] Furthermore, the polyurethane-grade solvent includes one or both of propylene glycol diacetate and propylene glycol methyl ether acetate.

[0031] Furthermore, the dehydrating agent is Additive OF.

[0032] According to another aspect of the present invention, a method for preparing a water-based coating for a photovoltaic frame is characterized by comprising the following steps:

[0033] The aqueous fluorinated hydroxy acrylic acid dispersion and the aqueous hydroxy acrylic acid dispersion were stirred at 400-600 rpm for 5-8 minutes until they were evenly mixed. Wetting agent, dispersant and defoamer were added at 400-600 rpm, followed by deionized water. The mixture was then dispersed at 400-600 rpm for 3-5 minutes.

[0034] Then add graphene and carbon black, increase the rotation speed to 2000-3000 rpm, disperse at high speed for 20-30 minutes, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain an aqueous dispersion, graphene and carbon black slurry;

[0035] Add silane oligomer, nano silica sol, polytetrafluoroethylene wax emulsion and leveling agent at a speed of 400-600 rpm, disperse for 5-10 min, adjust the speed to 600-800 rpm and add cosolvent, disperse for 20-30 min, finally add thickener at 600-800 rpm to adjust viscosity, filter and package to obtain component A;

[0036] Component B is prepared by mixing hydrophilic modified aliphatic polyisocyanate, polyurethane-grade solvent and dehydrating agent and stirring at 400-600 rpm for 5-10 min.

[0037] Mix component A and component B evenly, and then apply the mixture to the pretreated polyurethane composite frame substrate to form a protective coating.

[0038] Furthermore, the pretreatment process consists of substrate grinding, dust removal, and flame baking of the substrate.

[0039] Furthermore, the substrate is a polyurethane composite frame, including a polyurethane glass fiber composite frame and a polyurethane basalt fiber composite frame.

[0040] Furthermore, in the waterborne coating of the polyurethane composite material of the present invention, during the coating formation process, the hydroxyl functional groups and isocyanate functional groups undergo a cross-linking reaction to form a highly cross-linked coating. Simultaneously, during the coating formation process, siloxane oligomers and nano-silica sols undergo dehydration condensation to form siloxane-silicon bonds, and some silanol groups and isocyanate groups combine to form a macromolecular interpenetrating network structure, giving the coating both hardness and toughness. Utilizing the sheet barrier effect of the added graphene, the stacking effect of the graphene sheet structure forms a "maze-like" shielding structure in the coating structure, which can effectively inhibit the wetting, penetration and diffusion of corrosive media. The polytetrafluoroethylene wax emulsion is distributed throughout the entire coating during the coating formation process, and its low surface tension gives the coating excellent anti-fouling properties and can simultaneously improve the wear resistance of the coating.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] This invention uses a fluorinated aqueous hydroxy acrylic dispersion as a film-forming agent, resulting in an extremely low surface energy of the coating and greatly enhancing its anti-fouling properties. The polytetrafluoroethylene wax is uniformly distributed throughout the coating, providing excellent wear resistance and scratch resistance. The coating has high hardness and contains silicon-oxygen-silicon bonds in its structure, forming an organic-inorganic hybrid structure, which gives the coating both the toughness of an organic coating and the hardness of an inorganic coating.

[0043] The coating is based on fluorinated waterborne hydroxyl acrylic resin, combined with HDI-type isocyanate curing agent, and supplemented with graphene, silane oligomers and nano-silica sol, which gives the coating excellent aging resistance and effectively extends the service life of photovoltaic brackets. Therefore, the protective coating made of waterborne coating on the polyurethane composite frame of this invention has extremely low surface energy, effectively enhances the coating's anti-fouling effect, has high hardness, and combines the toughness of organic coatings with the hardness of inorganic coatings. It has outstanding aging resistance and can meet the long-term outdoor use of polyurethane composite materials.

[0044] After the water-based coating was applied to the surface of the polyurethane composite material, the profile passed an 8000-hour accelerated aging test under xenon lamp illumination, demonstrating excellent weather resistance. Furthermore, the protective coating obtained by this invention exhibits a damp heat resistance (85°C, 85% RH) ≥1000 hours and a PCT (temperature 121°C, saturated humidity 100% RH) ≥60 hours. Simultaneously, the water-based coating shows excellent adhesion to the polyurethane composite material as the substrate, and has extremely low VOC emissions. Photovoltaic modules with polyurethane composite frame frames coated with this water-based coating have been successfully tested. TÜV Rheinland certification proves that this new material can meet the stringent requirements of the photovoltaic industry, bringing high-performance low-carbon solutions to the industry, helping the photovoltaic industry develop, and contributing to achieving carbon peaking and carbon neutrality. Detailed Implementation

[0045] The present invention will be further described below through specific embodiments.

[0046] Example 1

[0047] Preparation of a water-based coating for photovoltaic frames:

[0048] First, stir 35 kg of ZT-9632 waterborne fluorinated hydroxy acrylic acid dispersion and 40 kg of Bayhydrol A2546 waterborne hydroxy acrylic acid dispersion at 500 rpm for 6 minutes until they are evenly mixed. Then, add 0.5 kg of BYK346 wetting agent, 1 kg of BYK190 dispersant and 0.3 kg of TEGO810 defoamer at 500 rpm. Next, add 5.4 kg of deionized water and continue to disperse at 500 rpm for 4 minutes.

[0049] Then add 1 kg of graphene and 2 kg of carbon black, increase the rotation speed to 2500 rpm, disperse at high speed for 25 min, then grind with a horizontal sand mill until the fineness is ≤20 μm, filter, and obtain aqueous dispersion, graphene and carbon black slurry;

[0050] Add 3 kg Momentive CoatOsil MP200 silane oligomer, 3 kg Grace HS-30 nano silica sol, 2 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.3 kg TEGO4100 leveling agent, and 1 kg CIBA1130 light stabilizer at 500 rpm and disperse for 8 min. Adjust the speed to 700 rpm and add 5 kg dipropylene glycol butyl ether cosolvent and disperse for 25 min. Finally, add 0.5 kg RM8W thickener at 700 rpm to adjust the viscosity. Filter and package to obtain component A.

[0051] Mix 60 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 38 kg of propylene glycol diacetate polyurethane grade solvent, and 2 kg of Additive OF dehydrating agent, and stir at 500 rpm for 8 min to obtain component B.

[0052] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 4:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0053] Example 2

[0054] Preparation of a water-based coating for photovoltaic frames;

[0055] First, stir 30 kg of ZT-9632 waterborne fluorinated hydroxy acrylic acid dispersion and 40 kg of Bayhydrol A2546 waterborne hydroxy acrylic acid dispersion at 400 rpm for 8 minutes until they are evenly mixed. Then, add 0.3 kg of Surfyno 104BC wetting agent, 0.8 kg of TEGO 755W dispersant and 0.4 kg of TEGO 902W defoamer at 400 rpm. Then add 1.5 kg of deionized water and continue to disperse at 400 rpm for 5 minutes.

[0056] Then add 0.8 kg of graphene and 2.2 kg of aluminum silver paste, increase the rotation speed to 2000 rpm, disperse at high speed for 30 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain aqueous dispersion, graphene and aluminum silver paste;

[0057] Add 2 kg Momentive CoatOsil MP200 silane oligomer, 4 kg Akzo LEVASILCT20PH nano silica sol, 3 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.5 kg TEGO Glide 450 leveling agent, and 0.8 kg CIBA292 light stabilizer at 400 rpm and disperse for 10 min. Adjust the speed to 600 rpm and add 6 kg dipropylene glycol methyl ether cosolvent and disperse for 30 min. Finally, add 0.8 kg RM2020 thickener at 600 rpm to adjust the viscosity. Filter and package to obtain component A.

[0058] Mix 55 kg of Covestro Bayhydur XP2655 hydrophilic modified aliphatic polyisocyanate, 42 kg of propylene glycol methyl ether acetate grade solvent, and 3 kg of Additive OF dehydrating agent, and stir at 400 rpm for 10 min to obtain component B.

[0059] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 5:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0060] Example 3

[0061] Preparation of a water-based coating for photovoltaic frames:

[0062] First, stir 20 kg of ZT-9632 water-based fluorinated hydroxy acrylic acid dispersion and 30 kg of Wanhua Chemical Antkote2702 water-based hydroxy acrylic acid dispersion at 600 rpm for 5 min. After mixing evenly, add 0.8 kg of PE100 wetting agent, 1.5 kg of TEGO760W dispersant and 0.8 kg of BYK02 defoamer at 600 rpm. Then add 10 kg of deionized water and continue to disperse at 600 rpm for 3 min.

[0063] Then add 1.2 kg of graphene and 5.5 kg of titanium dioxide, increase the rotation speed to 3000 rpm, disperse at high speed for 20 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain an aqueous dispersion, graphene and titanium dioxide slurry;

[0064] Add 3 kg Momentive CoatOsil MP200 silane oligomer, 1.5 kg Grace HS-30 nano silica sol, 2.5 kg Nanjing Tianshi PTFE1005 polytetrafluoroethylene wax emulsion, 0.8 kg TEGO4100 leveling agent, and 1.2 kg CIBA292 light stabilizer at 600 rpm and disperse for 5 min. Adjust the speed to 800 rpm and add 5.5 kg dipropylene glycol butyl ether cosolvent and disperse for 20 min. Finally, add 0.7 kg RM8W thickener at 800 rpm to adjust the viscosity, filter and package to obtain component A.

[0065] Mix 80 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 60 kg of propylene glycol diacetate polyurethane grade solvent, and 2 kg of Additive OF dehydrating agent, and stir at 600 rpm for 5 min to obtain component B.

[0066] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 6:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0067] Example 4

[0068] Preparation of a water-based coating for photovoltaic frames:

[0069] First, stir 40 kg of ZT-9632 waterborne fluorinated hydroxy acrylic acid dispersion and 35 kg of Bayhydrol A2546 waterborne hydroxy acrylic acid dispersion at 450 rpm for 7 min. After mixing evenly, add 1 kg of TEGO245 wetting agent, 2 kg of SN5040 dispersant and 1.5 kg of BYK024 defoamer at 450 rpm, then add 6 kg of deionized water and continue to disperse at 450 rpm for 5 min.

[0070] Then add 1.5 kg of graphene and 10 kg of carbon black, increase the rotation speed to 2800 rpm, disperse at high speed for 28 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain an aqueous dispersion, graphene and carbon black slurry;

[0071] Add 3 kg Momentive CoatOsil MP200 silane oligomer, 5 kg Akzo LEVASILCT20PH nano silica sol, 1.5 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.5 kg BYK378 leveling agent, and 0.3 kg CIBA1130 light stabilizer at 450 rpm and disperse for 8 min. Adjust the speed to 650 rpm and add 8 kg ethylene glycol butyl ether cosolvent and disperse for 22 min. Finally, add 0.7 kg RM12W thickener at 650 rpm to adjust the viscosity. Filter and package to obtain component A.

[0072] Mix 100 kg of LianGu Chemical 3598T hydrophilic modified aliphatic polyisocyanate, 90 kg of propylene glycol methyl ether acetate polyurethane grade solvent, and 3 kg of Additive OF dehydrating agent, and stir at 450 rpm for 6 min to obtain component B.

[0073] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 3:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0074] Example 5

[0075] Preparation of a water-based coating for photovoltaic frames:

[0076] First, stir 25 kg of ZT-9632 waterborne fluorinated hydroxy acrylic acid dispersion and 20 kg of Bayhydrol A2546 waterborne hydroxy acrylic acid dispersion at 550 rpm for 8 minutes until they are evenly mixed. Then, add 0.1 kg of BYK381 wetting agent, 0.2 kg of SN5040 dispersant and 0.2 kg of TEGO825 defoamer at 550 rpm. Next, add 1 kg of deionized water and continue to disperse at 550 rpm for 3 minutes.

[0077] Then add 0.5 kg of graphene and 1 kg of titanium dioxide, increase the rotation speed to 2250 rpm, disperse at high speed for 22 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain aqueous dispersion, graphene and titanium dioxide slurry;

[0078] Add 1 kg Momentive CoatOsil MP200 silane oligomer, 1 kg Grace HS-30 nano silica sol, 1 kg Nanjing Tianshi PTFE1005 polytetrafluoroethylene wax emulsion, 0.1 kg EFKA3033 leveling agent, and 0.2 kg CIBA292 light stabilizer at 550 rpm and disperse for 5 min. Adjust the speed to 750 rpm and add 1 kg diethylene glycol butyl ether cosolvent and disperse for 28 min. Finally, add 0.3 kg OMG0620 thickener at 750 rpm to adjust the viscosity. Filter and package to obtain component A.

[0079] Mix 20 kg of Covestro Bayhydur 401-70 hydrophilic modified aliphatic polyisocyanate, 10 kg of propylene glycol diacetate polyurethane solvent, and 1 kg of Additive OF dehydrating agent, and stir at 550 rpm for 7 min to obtain component B.

[0080] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 8:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0081] To further illustrate the key points of this application, comparative cases are provided.

[0082] Comparative Example 1

[0083] Preparation of a water-based coating for photovoltaic frames:

[0084] First, stir 65 kg of Wanhua Chemical's Antkote 2702 aqueous hydroxy acrylic dispersion at 500 rpm for 7 minutes until it is evenly mixed. Then, add 0.8 kg of BYK 346 wetting agent, 1.5 kg of BYK 190 dispersant, and 0.8 kg of TEGO 810 defoamer at 500 rpm. Next, add 12 kg of deionized water and continue to disperse at 500 rpm for 4 minutes.

[0085] Then add 1.2 kg of graphene and 2.5 kg of carbon black, increase the rotation speed to 2500 rpm, disperse at high speed for 25 min, then grind with a horizontal sand mill until the fineness is ≤20 μm, filter, and obtain aqueous dispersion, graphene and carbon black slurry;

[0086] Add 4 kg Momentive CoatOsil MP200 silane oligomer, 1.5 kg Grace HS-30 nano silica sol, 2.5 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.8 kg TEGO4100 leveling agent, and 1.2 kg CIBA292 light stabilizer at 500 rpm and disperse for 7 min. Adjust the speed to 700 rpm and add 5.5 kg dipropylene glycol butyl ether cosolvent and disperse for 25 min. Finally, add 0.7 kg RM8W thickener at 700 rpm to adjust the viscosity. Filter and package to obtain component A.

[0087] Mix 60 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 38 kg of propylene glycol diacetate polyurethane grade solvent, and 2 kg of Additive OF dehydrating agent, and stir at 500 rpm for 8 min to obtain component B.

[0088] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 6:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0089] Comparative Example 2

[0090] Preparation of a water-based coating for photovoltaic frames:

[0091] First, stir 65 kg of ZT-9632 water-based fluorinated hydroxyl acrylic dispersion at 400 rpm for 8 minutes until it is evenly mixed. Then, add 0.8 kg of BYK346 wetting agent, 1.5 kg of BYK190 dispersant and 0.8 kg of TEGO810 defoamer at 400 rpm. Next, add 12 kg of deionized water and continue to disperse at 600 rpm for 5 minutes.

[0092] Then add 1.2 kg of graphene and 2.5 kg of carbon black, increase the rotation speed to 2000 rpm, disperse at high speed for 30 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain an aqueous dispersion, graphene and carbon black slurry;

[0093] Add 4 kg Momentive CoatOsil MP200 silane oligomer, 1.5 kg Grace HS-30 nano silica sol, 2.5 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.8 kg TEGO4100 leveling agent, and 1.2 kg CIBA292 light stabilizer at 600 rpm and disperse for 5 min. Adjust the speed to 600 rpm and add 5.5 kg dipropylene glycol butyl ether cosolvent and disperse for 30 min. Finally, add 0.7 kg RM8W thickener at 600 rpm to adjust the viscosity. Filter and package to obtain component A.

[0094] Mix 60 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 38 kg of propylene glycol diacetate polyurethane solvent, and 2 kg of Additive OF dehydrating agent, and stir at 600 rpm for 5 min to obtain component B.

[0095] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 7:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0096] Comparative Example 3

[0097] Preparation of a water-based coating for photovoltaic frames:

[0098] First, 30 kg of ZT-9632 waterborne fluorinated hydroxy acrylic acid dispersion and 35 kg of Wanhua Chemical Antkote2032 waterborne hydroxy acrylic acid dispersion were stirred at 400 rpm for 8 minutes. After mixing evenly, 0.8 kg of BYK346 wetting agent, 1.5 kg of BYK190 dispersant and 0.8 kg of TEGO810 defoamer were added at 400 rpm. Then, 12 kg of deionized water was added and the mixture was further dispersed at 400 rpm for 5 minutes.

[0099] Then add 1.2 kg of graphene and 2.5 kg of carbon black, increase the rotation speed to 2000 rpm, disperse at high speed for 30 min, then grind with a horizontal sand mill to a fineness of ≤20 μm, filter, and obtain an aqueous dispersion, graphene and carbon black slurry;

[0100] Add 4 kg Momentive CoatOsil MP200 silane oligomer, 1.5 kg Grace HS-30 nano silica sol, 2.5 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.8 kg TEGO4100 leveling agent, and 1.2 kg CIBA292 light stabilizer at 400 rpm and disperse for 10 min. Adjust the speed to 600 rpm and add 5.5 kg dipropylene glycol butyl ether cosolvent and disperse for 20 min. Finally, add 0.7 kg RM8W thickener at 600 rpm to adjust the viscosity. Filter and package to obtain component A.

[0101] Mix 60 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 38 kg of propylene glycol diacetate polyurethane grade solvent, and 2 kg of Additive OF dehydrating agent, and stir at 400 rpm for 10 min to obtain component B.

[0102] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 3:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0103] Comparative Example 4

[0104] Preparation of a water-based coating for photovoltaic frames:

[0105] First, mix 30 kg of WF-D2245 waterborne fluorinated hydroxy acrylic acid dispersion and 35 kg of Wanhua Chemical Antkote2702 waterborne hydroxy acrylic acid dispersion at 600 rpm for 5 minutes. After mixing evenly, add 0.8 kg of BYK346 wetting agent, 1.5 kg of BYK190 dispersant and 0.8 kg of TEGO810 defoamer at 600 rpm. Then add 12 kg of deionized water and continue to disperse at 600 rpm for 3 minutes.

[0106] Then add 1.2 kg of graphene and 2.5 kg of carbon black, increase the rotation speed to 3000 rpm, disperse at high speed for 20 min, then grind with a horizontal sand mill until the fineness is ≤20 μm, filter, and obtain aqueous dispersion, graphene and carbon black slurry;

[0107] Add 4 kg Momentive CoatOsil MP200 silane oligomer, 1.5 kg Grace HS-30 nano silica sol, 2.5 kg Nanjing Tianshi PTFE-1008 polytetrafluoroethylene wax emulsion, 0.8 kg TEGO4100 leveling agent, and 1.2 kg CIBA292 light stabilizer at 600 rpm and disperse for 5 min. Adjust the speed to 800 rpm and add 5.5 kg dipropylene glycol butyl ether cosolvent and disperse for 20 min. Finally, add 0.7 kg RM8W thickener at 800 rpm to adjust the viscosity. Filter and package to obtain component A.

[0108] Mix 60 kg of Wanhua Chemical Aquolin 269A hydrophilic modified aliphatic polyisocyanate, 38 kg of propylene glycol diacetate polyurethane solvent, and 2 kg of Additive OF dehydrating agent, and stir at 600 rpm for 5 min to obtain component B.

[0109] After sandblasting and flame baking the surface of the polyurethane composite frame, mix components A and B thoroughly at a ratio of 8:1 (by mass). After standing for 5 minutes, spray the coating onto the polyurethane composite frame. The dry film thickness should be ≥30 μm. Bake at 80°C for 30 minutes to complete the process.

[0110] The coatings prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in Table 1.

[0111] Table 1

[0112]

[0113]

[0114] As shown in Table 1, by comparing the examples and Comparative Example 1, the coating prepared without the addition of water-based fluorinated hydroxy acrylic dispersions exhibits significantly reduced properties such as aging resistance, wet-freeze resistance, damp-heat resistance, and PCT (high-pressure accelerated damp-heat aging). By comparing the examples and Comparative Example 2, the coating prepared without the addition of water-based hydroxy acrylic dispersions exhibits significantly reduced properties such as abrasion resistance, aging resistance, damp-heat resistance, salt spray corrosion resistance, and PCT (high-pressure accelerated damp-heat aging). By comparing the examples and Comparative Example 3, the coating prepared using other types of water-based hydroxy acrylic dispersions exhibits significantly reduced properties such as wet-freeze resistance, damp-heat resistance, salt spray corrosion resistance, and PCT (high-pressure accelerated damp-heat aging). By comparing the examples and Comparative Example 4, the coating prepared using other types of water-based fluorinated hydroxy acrylic dispersions (Comparative Example 4) exhibits significantly reduced properties such as abrasion resistance, aging resistance, wet-freeze resistance, salt spray corrosion resistance, and PCT (high-pressure accelerated damp-heat aging).

[0115] Therefore, by using the water-based fluorinated hydroxyl acrylic dispersion used in this application, and by combining the raw materials used in this application, excellent wear resistance, aging resistance, wet freeze resistance, wet heat resistance, salt spray corrosion resistance, and PCT (high pressure accelerated wet heat aging) performance can be achieved simultaneously, effectively extending the service life of the polyurethane composite frame for photovoltaic applications.

[0116] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A water-based coating for a photovoltaic frame, characterized by, The A component and the B component are included; The A component includes the following raw materials in mass fraction: The B component includes the following raw materials in mass fraction: Hydrophilic modified aliphatic polyisocyanate 10-100 parts Polyurethane grade solvent 0-90 parts Dehydrating agent 1-3 parts; The A component:B component = (3-8):1; The water-based fluorine-containing hydroxyl acrylic acid dispersion is ZT-9632 from Zhiti Technology Co., Ltd. The water-based hydroxyl acrylic acid dispersion includes one or both of Bayhydrol A2546 from Covestro and Antkote 2702 from Wanhua Chemical.

2. The water-based paint for photovoltaic frame according to claim 1, wherein The silane oligomer is CoatOsil MP200 from Momentive; The graphene is the sixth element 1132; The nano-silica sol includes one or both of LEVASIL CT20PH from Aksu and HS-30 from Grace; The polytetrafluoroethylene wax emulsion includes one or both of PTFE-1008 and PTFE1005 from Nanjing Tianshi.

3. The water-based paint for photovoltaic frame according to claim 1, wherein The pigment includes one or more of carbon black, aluminum silver paste, and titanium dioxide; The co-solvent includes one or more of dipropylene glycol butyl ether, dipropylene glycol methyl ether, ethylene glycol butyl ether, and diethylene glycol butyl ether; The auxiliary agent includes the following raw materials in mass fraction: wetting agent 0-1 part, dispersant 0-3 parts, defoaming agent 0-2 parts, leveling agent 0-2 parts, thickening agent 0-2 parts, and light stabilizer 0-2 parts. 4.The water-based coating for photovoltaic frame according to claim 3, characterized in that, The wetting agent is one or more of BYK346, surfyno 104BC, PE100, TEGO270, TEGO245, TEGO450, and BYK381; The dispersant is one or more of TEGO755W, TEGO757W, BYK190, SN5040, TEGO752W, TEGO760W, TEGO750W, BYK191, BYK192, BYK194N, and BYK199; The defoaming agent is one or more of TEGO810, TEGO902W, TEGO904W, TEGO822, TEGO825, BYK024, BYK011, BYK021, and BYK028; The leveling agent is one or more of TEGO410, TEGO4100, TEGOGlide450, EFKA3033, BYK333, and BYK378; The thickening agent is one or more of RM2020, RM8W, RM12W, Humes 299, and OMG0620; The light stabilizer is an ultraviolet absorber, including one or both of CIBA292 and CIBA1130. 5.The water-based coating for photovoltaic frame according to claim 1, characterized in that, The hydrophilic modified aliphatic polyisocyanate includes one or more of Bayhydur XP2655, Bayhydur 401-70, Aquolin 269A, and 3598T from Liangu Chemical. 6.The water-based coating for photovoltaic frame according to claim 1, characterized in that, The polyurethane grade solvent includes one or both of propylene glycol diacetate and propylene glycol methyl ether acetate; the dehydrating agent is Additive OF.

7. A process for the preparation of a waterborne coating for photovoltaic frames according to any one of claims 1-6, characterized in that, The method comprises the following steps: The aqueous fluorine-containing hydroxyl acrylic dispersion and the aqueous hydroxyl acrylic dispersion are stirred at a speed of 400-600 rpm for 5-8 min, and are mixed uniformly; the wetting agent, the dispersing agent and the defoaming agent are added at a speed of 400-600 rpm, and then deionized water is added; the dispersion is continued for 3-5 min at a speed of 400-600 rpm; Then the graphene and the pigment are added, the speed is increased to 2000-3000 rpm, and the high-speed dispersion is performed for 20-30 min; then the horizontal sand mill is used for grinding to a fineness of ≤20 um, and filtration is performed to obtain the aqueous dispersion, the graphene and the corresponding slurry; The silane oligomer, the nano-silica sol, the polytetrafluoroethylene wax emulsion and the leveling agent are added at a speed of 400-600 rpm, and the dispersion is performed for 5-10 min; the speed is adjusted to 600-800 rpm, the cosolvent is added, and the dispersion is performed for 20-30 min; finally, the thickening agent is added at a speed of 600-800 rpm to adjust the viscosity, and filtration and packaging are performed to obtain the A component; The hydrophilic modified aliphatic polyisocyanate, the polyurethane grade solvent and the dehydrating agent are mixed, and stirred at a speed of 400-600 rpm for 5-10 min to obtain the B component; The A component and the B component are mixed uniformly, and then are coated on the polyurethane composite frame substrate which has been pretreated, so that the protective coating is obtained.

8. The method of claim 7, wherein the water-based coating for a photovoltaic frame is prepared by adding 0.1 to 1 parts by weight of the dispersant to 100 parts by weight of the water-based coating for a photovoltaic frame. The pretreatment process comprises the following steps in sequence: substrate polishing, soot blowing and flame baking of the substrate.

9. The method of claim 7, wherein the water-based coating for a photovoltaic frame is prepared by adding 0.1 to 1 parts by weight of the dispersant to 100 parts by weight of the water-based coating for a photovoltaic frame. The substrate is a polyurethane composite frame, including a polyurethane glass fiber composite frame and a polyurethane basalt fiber composite frame.

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