Self-cleaning weather-proof aluminum alloy photovoltaic module frame and preparation method thereof

Abstract

The invention relates to the technical field of photovoltaic module frames, in particular to a self-cleaning weather-proof aluminum alloy photovoltaic module frame and a preparation method thereof, and aims to improve the self-cleaning capacity of the photovoltaic module frame, a layer of self-cleaning coating is prepared on the basis of an aluminum alloy frame body. The boric acid ester chain extender containing the fluorine element and the fluorine-containing polyol are added, and the fluorine element has extremely strong electronegativity, so that the water resistance of the resin can be effectively improved, the surface energy of the material is reduced, the surface friction is reduced, the friction resistance is improved, the adsorption of dust on the surface of a metal frame can be reduced, and the material is kept clean for a long time; a reversible covalent bond boric acid ester bond is further introduced into the boric acid ester chain extender, so that the purpose of self-repairing is achieved, hydrophobic nano-silica is further added into the coating, the friction resistance and hydrophobic capacity of the aluminum alloy photovoltaic module frame are further improved, and the service life of the aluminum alloy photovoltaic module frame is prolonged. And the durability of the material exposed in an external atmospheric environment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic module frames, and specifically to a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame and a preparation method thereof. Background Art

[0002] The aluminum alloy photovoltaic module frame is the peripheral support structure of the photovoltaic power generation panel, with the performance advantages of light weight and high strength, and is the mainstream frame material for current photovoltaic modules; however, during use, since the photovoltaic power generation panel needs to be exposed to the outdoor environment for a long time and needs to face environments such as water vapor erosion and acid rain corrosion, it often has extremely high requirements for its corrosion resistance. And in the daily environment, dust particles in the air will continuously accumulate on the photovoltaic panel and the photovoltaic module frame, resulting in a decrease in power generation efficiency and pollution of the frame, further exacerbating the corrosion of the frame. Therefore, it is necessary to prepare an aluminum alloy photovoltaic module frame with a self-cleaning function to address this defect. Summary of the Invention

[0003] The purpose of the present invention is to provide a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame and a preparation method thereof to solve the problems raised in the prior art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, including the following steps:

[0005] S1. Prepare a waterborne polyurethane emulsion;

[0006] Mix fluorinated polyol and polytetrahydrofuran ether glycol, stir evenly, then vacuum dry to remove water. Under a nitrogen atmosphere, add isocyanate monomer, raise the temperature to 70 - 80 °C, stir and react for 2 - 4 h, then lower the temperature to 60 - 70 °C, continue to add borate chain extender, small molecule chain extender, and dibutyltin dilaurate, continue to stir and react for 2 - 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and stir at high speed for emulsification to obtain a waterborne polyurethane emulsion with a solid content of 35 - 45%;

[0007] S2. Prepare a self-cleaning and weather-resistant coating;

[0008] Add hydrophobic nano-silica, leveling agent, and defoaming agent to the waterborne polyurethane emulsion, stir and shear mix at high speed, and pass through a 15 - 30 μm sieve to obtain a self-cleaning and weather-resistant coating;

[0009] S3. Prepare a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame:

[0010] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively, then dry it, and perform corona treatment on its surface;

[0011] S32. Spray a self-cleaning weather-resistant coating on the surface of the corona-treated aluminum alloy frame. After spraying, heat it to 105 - 115 °C and dry and cure for 15 - 30 min to form a self-cleaning weather-resistant coating with a thickness of 15 - 45 μm on the surface of the aluminum alloy frame, thus obtaining a self-cleaning weather-resistant aluminum alloy photovoltaic module frame.

[0012] Further, in step S1, by weight, the mass ratio of the fluorinated polyol, polytetrahydrofuran ether diol, isocyanate monomer, borate chain extender, small molecule chain extender, and dibutyltin dilaurate is (1.2 - 1.7):(2.8 - 3.2):(1.2 - 1.35):(0.6 - 0.9):(0.08 - 0.1):(0.0005 - 0.0008).

[0013] Further, the molecular weight of the polytetrahydrofuran ether diol is 1500 - 2500; the isocyanate monomer is isophorone diisocyanate; the small molecule chain extender is 1,4-butanediol.

[0014] Further, in step S1, the preparation method of the borate chain extender is as follows:

[0015] Heat DMF to 115 - 120 °C, keep it warm for 30 - 90 min, then cool it to room temperature. Mix 5-carbamoyl-2-fluorobenzeneboronic acid with DMF, stir evenly, and then dropwise add a DMF solution containing 2-amino-1,3-propanediol drop by drop while stirring continuously. After reacting in the dark at room temperature for 18 - 36 h, dropwise add glycidol again, heat it to 78 - 86 °C, stir and react for 2 - 6 h, and then rotary evaporate to remove the excess solvent to obtain the borate chain extender.

[0016] Further, by mole, the molar ratio of 5-carbamoyl-2-fluorobenzeneboronic acid, 2-amino-1,3-propanediol, and glycidol is 1:(0.95 - 1):(1.98 - 2.02).

[0017] Further, in step S1, the preparation method of the fluorinated polyol is as follows:

[0018] Disperse tetrafluoroterephthalic acid in DMF, add EDC, stir and mix evenly, then dropwise add 1,3-bis(aminopropyl)tetramethyldisiloxane, heat it to 115 - 125 °C, stir and react for 8 - 16 h, stop heating, cool it to room temperature, then dropwise add a DMF solution containing 10-amino-1-decanol drop by drop. After the addition is completed, heat it to 95 - 105 °C and continue to stir and react for 24 - 48 h, and then rotary evaporate to remove the excess solvent to obtain the fluorinated polyol.

[0019] Further, in terms of molar parts, the molar ratio of tetrafluoroterephthalic acid, 1,3-bis(aminopropyl)tetramethyldisiloxane, and 10-amino-1-decanol is (1.85 - 2):1:(1.95 - 2.05).

[0020] Further, in step S2, in terms of weight parts, the self-cleaning weather-resistant coating is composed of 100 parts of waterborne polyurethane emulsion, 2.5 - 5 parts of hydrophobic nano-silica, 0.2 - 0.35 parts of leveling agent, and 0.4 - 0.8 parts of defoaming agent.

[0021] Further, in step S31, during corona treatment, the voltage is 5 - 20 kV, the power is 0.5 - 1.5 kW, and the treatment speed is 1 - 10 m / s.

[0022] Further, a self-cleaning weather-resistant aluminum alloy photovoltaic module frame is prepared by the above method.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] In order to improve the self-cleaning ability of the photovoltaic module frame, the present invention prepares a self-cleaning coating on the basis of the aluminum alloy frame body. The present invention first prepares a borate chain extender containing fluorine element and borate ester bond. Using 5-carbamoyl-2-fluorophenylboronic acid and 2-amino-1,3-propanediol as raw materials, an intermediate with borate ester bond is synthesized, and further it is mixed with glycidol containing epoxy group to synthesize and prepare a chain extender containing fluorine element and borate ester bond, and the end is capped with alcohol hydroxyl group. The borate ester bond therein is a reversible covalent bond. In the case of being damaged by the outside world, the borate ester bond can self-assemble and react to realize the recombination between groups again, so as to achieve the purpose of self-repair. The fluorine element added therein has extremely strong electronegativity, which can effectively improve the water resistance of the resin, significantly improve the hydrolysis stability of the borate ester, and enhance the water resistance of the material. And the introduction of fluorine element can also effectively reduce the surface energy of the material, reduce the surface friction and improve the friction resistance, while reducing the accumulation and adsorption of dust on the surface of the metal frame, and keeping the material clean for a long time.

[0025] On this basis, the present invention also synthesizes a fluorinated polyol containing fluorine and silicon elements, and further introduces fluorine element therein, making the synthesized resin have stronger hydrophobic performance. At the same time, the strong electronegativity of fluorine element will further form a helical structure in the carbon chain, thus effectively isolating the contact with external oxygen, water vapor, acids and bases and other substances, improving the stability of the material. And in this application, Si - O bond is also introduced into the main chain of the fluorinated polyol, which has high bond energy and can further improve the stability of the resin chain segment and enhance the resistance of the resin to external erosion.

[0026] Moreover, the present invention also adds hydrophobic nano-silica to the coating, further improving the friction resistance and hydrophobic ability of the aluminum alloy photovoltaic module frame, and enhancing its durability when exposed to the external atmospheric environment. Detailed implementation manners

[0027] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] In this application, the polytetrahydrofuran ether diol used has a Mw of 2000; the hydrophobic nano-silica used is Cabot TS-620 type hydrophobic fumed nano-silica; the leveling agent used is BYK-333 type waterborne leveling agent; the defoaming agent used is Datian Chemical DT-650 type waterborne coating defoaming agent;

[0029] Example 1. A preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0030] S1. Prepare a waterborne polyurethane emulsion;

[0031] By weight, 1.2 parts of fluorinated polyol and 2.8 parts of polytetrahydrofuran ether diol are mixed, stirred evenly, vacuum dried and dehydrated. Under a nitrogen atmosphere, 1.2 parts of isocyanate monomer are added, the temperature is raised to 78 °C, and after stirring and reacting for 3 h, the temperature is lowered to 70 °C. Then, 0.6 part of borate chain extender, 0.09 part of 1,4-butanediol, and 0.0008 part of dibutyltin dilaurate are added, and stirring and reacting continue for 3 h. Then, triethylamine is added to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, deionized water is added, and high-speed stirring and emulsification are carried out to obtain a waterborne polyurethane emulsion with a solid content of 37%;

[0032] Among them, the preparation method of the borate chain extender is as follows:

[0033] By molar fraction, DMF is heated to 115 °C, kept warm for 30 min, and then cooled to room temperature. 1 molar part of 5-carbamoyl-2-fluorobenzeneboronic acid is mixed with DMF, stirred evenly, and then a DMF solution containing 0.95 molar part of 2-amino-1,3-propanediol is added dropwise thereto. During the dropping process, continuous stirring is carried out. After reacting in the dark at room temperature for 24 h, 1.98 molar parts of glycidol are added dropwise thereto again. The temperature is raised to 82 °C, and after stirring and reacting for 4 h, the excess solvent is removed by rotary evaporation to obtain the borate chain extender;

[0034] The preparation method of the fluorinated polyol is as follows:

[0035] By mole fraction, 1.85 mole fractions of tetrafluoroterephthalic acid were dispersed in DMF, EDC was added thereto, and after stirring and mixing evenly, 1 mole fraction of 1,3-bis(aminopropyl)tetramethyldisiloxane was added dropwise thereto. The temperature was raised to 120 °C, and after stirring and reacting for 12 h, heating was stopped. After cooling to room temperature, a DMF solution containing 1.95 mole fractions of 10-amino-1-decanol was added dropwise thereto. After the addition was completed, the temperature was raised to 100 °C, and after continuing to stir and react for 24 h, the excess solvent was removed by rotary evaporation to obtain a fluorinated polyol;

[0036] S2. Prepare a self-cleaning weather-resistant coating;

[0037] By weight, 2.5 parts of hydrophobic nano-silica, 0.3 part of leveling agent and 0.6 part of defoaming agent were added to 100 parts of aqueous polyurethane emulsion, and they were stirred, sheared and mixed at high speed, and passed through a 30-μm sieve to obtain a self-cleaning weather-resistant coating;

[0038] S3. Prepare a self-cleaning weather-resistant aluminum alloy photovoltaic module frame:

[0039] S31. The surface of the aluminum alloy frame was washed with deionized water and anhydrous ethanol respectively and then dried, and its surface was subjected to corona treatment. During the corona treatment, the voltage was 15 kV, the power was 1 kW, and the treatment speed was 5 m / s;

[0040] S32. The self-cleaning weather-resistant coating was sprayed on the surface of the aluminum alloy frame after corona treatment. After spraying, the temperature was raised to 110 °C, and after drying and curing for 20 min, a self-cleaning weather-resistant coating with a thickness of 30 μm was formed on the surface of the aluminum alloy frame to obtain a self-cleaning weather-resistant aluminum alloy photovoltaic module frame.

[0041] Example 2. A preparation method of a self-cleaning weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0042] Compared with Example 1, this example adds the fluorinated polyol in step S1;

[0043] S1. Prepare an aqueous polyurethane emulsion;

[0044] By weight, 1.7 parts of fluorinated polyol and 2.8 parts of polytetrahydrofuran ether diol were mixed, stirred evenly, dried and dehydrated under vacuum. Under a nitrogen atmosphere, 1.2 parts of isocyanate monomer were added, the temperature was raised to 78 °C, and after stirring and reacting for 3 h, the temperature was lowered to 70 °C. Then 0.6 part of borate chain extender, 0.09 part of 1,4-butanediol and 0.0008 part of dibutyltin dilaurate were added, and after continuing to stir and react for 3 h, triethylamine was added to neutralize and form a salt. After detecting that the pH value was 6.8 - 7.2, deionized water was added, and it was emulsified by high-speed stirring to obtain an aqueous polyurethane emulsion with a solid content of 37%;

[0045] Among them, the preparation method of the borate chain extender is as follows:

[0046] Calculated by mole fraction, heat DMF to 115 °C, keep it warm for 30 min, then cool it to room temperature. Mix 1 mole fraction of 5-carbamoyl-2-fluorobenzeneboronic acid with DMF, stir evenly, and then dropwise add a DMF solution containing 0.95 mole fraction of 2-amino-1,3-propanediol drop by drop while continuously stirring. After reacting in the dark at room temperature for 24 h, dropwise add 1.98 mole fraction of glycidol to it again, raise the temperature to 82 °C, stir and react for 4 h, then rotary evaporate to remove the excess solvent to obtain the borate chain extender;

[0047] The preparation method of the fluorinated polyol is as follows:

[0048] Calculated by mole fraction, disperse 1.85 mole fraction of tetrafluoroterephthalic acid in DMF, add EDC to it, stir and mix evenly, then dropwise add 1 mole fraction of 1,3-bis(aminopropyl)tetramethyldisiloxane to it, raise the temperature to 120 °C, stir and react for 12 h, then stop heating. After cooling to room temperature, dropwise add a DMF solution containing 1.95 mole fraction of 10-amino-1-decanol to it. After the addition is completed, heat up to 100 °C and continue to stir and react for 24 h, then rotary evaporate to remove the excess solvent to obtain the fluorinated polyol;

[0049] S2. Prepare a self-cleaning and weather-resistant coating;

[0050] By weight, add 2.5 parts of hydrophobic nano-silica, 0.3 part of leveling agent and 0.6 part of defoaming agent to 100 parts of aqueous polyurethane emulsion, stir, shear and mix at high speed, and pass through a 30 μm sieve to obtain a self-cleaning and weather-resistant coating;

[0051] S3. Prepare a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame:

[0052] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it, and perform corona treatment on its surface. When performing corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0053] S32. Spray the self-cleaning and weather-resistant coating on the surface of the corona-treated aluminum alloy frame. After spraying, raise the temperature to 110 °C, dry and cure for 20 min, and form a self-cleaning and weather-resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame to obtain a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame.

[0054] Example 3. A preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0055] Compared with Example 1, the addition amounts of 2-amino-1,3-propanediol and glycidol in step S1 are increased in this example.

[0056] S1. Prepare an aqueous polyurethane emulsion;

[0057] Mix 1.2 parts by weight of fluorinated polyol and 2.8 parts by weight of polytetrahydrofuran ether glycol, stir evenly, then conduct vacuum drying for dehydration. Under a nitrogen atmosphere, add 1.2 parts by weight of isocyanate monomer, raise the temperature to 78 °C, stir and react for 3 h, then cool to 70 °C, continue to add 0.6 part by weight of borate chain extender, 0.09 part by weight of 1,4-butanediol, and 0.0008 part by weight of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine for neutralization to form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and conduct high-speed stirring for emulsification to obtain an aqueous polyurethane emulsion with a solid content of 37%;

[0058] Among them, the preparation method of the borate chain extender is as follows:

[0059] Heat DMF to 115 °C according to molar parts, keep it warm for 30 min, then cool to room temperature. Mix 1 molar part of 5-carbamoyl-2-fluorobenzeneboronic acid with DMF, stir evenly, then dropwise add a DMF solution containing 1 molar part of 2-amino-1,3-propanediol thereto, continuously stir during the dropping process, react in the dark at room temperature for 24 h, then dropwise add 2.02 molar parts of glycidol thereto again, raise the temperature to 82 °C, stir and react for 4 h, then remove the excess solvent by rotary evaporation to obtain the borate chain extender;

[0060] The preparation method of the fluorinated polyol is as follows:

[0061] Disperse 1.85 molar parts of tetrafluoroterephthalic acid in DMF, add EDC thereto, stir and mix evenly, then dropwise add 1 molar part of 1,3-bis(aminopropyl)tetramethyldisiloxane thereto, raise the temperature to 120 °C, stir and react for 12 h, then stop heating. After cooling to room temperature, dropwise add a DMF solution containing 1.95 molar parts of 10-amino-1-decanol thereto. After the dropping is completed, heat and raise the temperature to 100 °C, continue to stir and react for 24 h, then remove the excess solvent by rotary evaporation to obtain the fluorinated polyol;

[0062] S2. Prepare a self-cleaning and weather-resistant coating;

[0063] Add 2.5 parts by weight of hydrophobic nano-silica, 0.3 part by weight of leveling agent, and 0.6 part by weight of defoaming agent to 100 parts by weight of the aqueous polyurethane emulsion, conduct high-speed stirring and shearing for mixing, and pass through a 30-μm sieve to obtain a self-cleaning and weather-resistant coating;

[0064] S3. Prepare a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame:

[0065] S31. Wash the surface of the aluminum alloy frame with deionized water and absolute ethanol respectively and then dry it. Carry out corona treatment on its surface. When carrying out corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0066] S32. Spray a self-cleaning weather-resistant coating on the surface of the aluminum alloy frame after corona treatment. After spraying, heat up to 110 °C, dry and cure for 20 min, and form a self-cleaning weather-resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame, obtaining a self-cleaning weather-resistant aluminum alloy photovoltaic module frame.

[0067] Example 4. A preparation method of a self-cleaning weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0068] Compared with Example 3, in this example, the addition amounts of terephthalic acid alcohol and 10-amino-1-decanol in step S1 are increased;

[0069] S1. Prepare an aqueous polyurethane emulsion;

[0070] By weight, mix 1.2 parts of fluorinated polyol and 2.8 parts of polytetrahydrofuran ether glycol, stir evenly, then carry out vacuum drying and dehydration. Under a nitrogen atmosphere, add 1.2 parts of isocyanate monomer, heat up to 78 °C, stir and react for 3 h, then cool down to 70 °C, continue to add 0.6 part of borate chain extender, 0.09 part of 1,4-butanediol, and 0.0008 part of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and carry out high-speed stirring and emulsification to obtain an aqueous polyurethane emulsion with a solid content of 37%;

[0071] Among them, the preparation method of the borate chain extender is as follows:

[0072] By mole, heat DMF to 115 °C, keep it warm for 30 min, then cool it to room temperature. Mix 1 mole of 5-carbamoyl-2-fluorobenzeneboronic acid with DMF, stir evenly, and then dropwise add a DMF solution containing 1 mole of 2-amino-1,3-propanediol into it. Keep stirring during the dropping process. After reacting in the dark at room temperature for 24 h, dropwise add 2.02 moles of glycidol into it again, heat up to 82 °C, stir and react for 4 h, then rotary evaporate to remove the excess solvent to obtain the borate chain extender;

[0073] The preparation method of the fluorinated polyol is as follows:

[0074] In terms of molar parts, disperse 2 molar parts of tetrafluoro terephthalic acid into DMF, add EDC thereto, stir and mix evenly, then dropwise add 1 molar part of 1,3-bis(aminopropyl)tetramethyldisiloxane thereto, raise the temperature to 120 °C, stir and react for 12 h, stop heating, cool to room temperature, then dropwise add the DMF solution containing 2.05 molar parts of 10-amino-1-decanol thereto. After the dropping is completed, heat up to 100 °C and continue to stir and react for 24 h, then rotary evaporate to remove the excess solvent to obtain a fluorinated polyol;

[0075] S2. Prepare a self-cleaning and weather-resistant coating;

[0076] By weight, add 2.5 parts of hydrophobic nano-silica, 0.3 part of leveling agent and 0.6 part of defoaming agent to 100 parts of aqueous polyurethane emulsion, stir, shear and mix at high speed, and pass through a 30-μm sieve to obtain a self-cleaning and weather-resistant coating;

[0077] S3. Prepare a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame:

[0078] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it, and perform corona treatment on its surface. When performing corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0079] S32. Spray the self-cleaning and weather-resistant coating on the surface of the corona-treated aluminum alloy frame. After spraying, raise the temperature to 110 °C, dry and cure for 20 min, and form a self-cleaning and weather-resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame to obtain a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame.

[0080] Example 5. A preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0081] Compared with Example 1, the amount of hydrophobic nano-silica added in step S2 is increased in this example;

[0082] S1. Prepare an aqueous polyurethane emulsion;

[0083] By weight, mix 1.2 parts of fluorinated polyol and 2.8 parts of polytetrahydrofuran ether glycol, stir evenly, then vacuum dry and dehydrate. Under a nitrogen atmosphere, add 1.2 parts of isocyanate monomer, raise the temperature to 78 °C, stir and react for 3 h, then cool to 70 °C, continue to add 0.6 part of borate chain extender, 0.09 part of 1,4-butanediol, 0.0008 part of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and stir and emulsify at high speed to obtain an aqueous polyurethane emulsion with a solid content of 37%;

[0084] S2. Prepare a self - cleaning weather - resistant coating;

[0085] By weight, add 5 parts of hydrophobic nano - silica, 0.3 parts of leveling agent and 0.6 parts of defoaming agent to 100 parts of water - borne polyurethane emulsion, stir and shear - mix at high speed, and pass through a 30 - μm sieve to obtain a self - cleaning weather - resistant coating;

[0086] S3. Prepare a self - cleaning weather - resistant aluminum alloy photovoltaic module frame:

[0087] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it. Perform corona treatment on its surface. When performing corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0088] S32. Spray the self - cleaning weather - resistant coating on the surface of the corona - treated aluminum alloy frame. After spraying, heat up to 110 °C, dry and cure for 20 min, and form a self - cleaning weather - resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame to obtain a self - cleaning weather - resistant aluminum alloy photovoltaic module frame.

[0089] Comparative Example 1. A preparation method of a self - cleaning weather - resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0090] Compared with Example 1, in this comparative example, fluorinated polyol was not prepared and used, but polyethylene glycol with Mw of 1000 was used for equal - mass substitution;

[0091] S1. Prepare a water - borne polyurethane emulsion;

[0092] By weight, mix 1.2 parts of polyethylene glycol and 2.8 parts of polytetrahydrofuran ether glycol, stir evenly, then dry and dehydrate under vacuum. Under a nitrogen atmosphere, add 1.2 parts of isocyanate monomer, heat up to 78 °C, stir and react for 3 h, then cool down to 70 °C, continue to add 0.6 parts of borate chain extender, 0.09 parts of 1,4 - butanediol, 0.0008 parts of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and stir and emulsify at high speed to obtain a water - borne polyurethane emulsion with a solid content of 37%;

[0093] Among them, the preparation method of the borate chain extender is:

[0094] By mole fraction, heat DMF to 115 °C, keep warm for 30 min, then cool to room temperature. Mix 1 mole fraction of 5-carbamoyl-2-fluorophenylboronic acid with DMF, stir evenly, and then dropwise add a DMF solution containing 0.95 mole fraction of 2-amino-1,3-propanediol thereto. Keep stirring during the dropping process. After reacting in the dark at room temperature for 24 h, dropwise add 1.98 mole fraction of glycidol thereto again, heat up to 82 °C, stir and react for 4 h, then rotary evaporate to remove the excess solvent to obtain a borate chain extender;

[0095] S2. Prepare a self-cleaning and weather-resistant coating;

[0096] By weight, add 2.5 parts of hydrophobic nano-silica, 0.3 part of leveling agent and 0.6 part of defoaming agent to 100 parts of aqueous polyurethane emulsion, stir and shear mix at high speed, and pass through a 30 μm sieve to obtain a self-cleaning and weather-resistant coating;

[0097] S3. Prepare a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame:

[0098] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it, and perform corona treatment on its surface. When performing corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0099] S32. Spray the self-cleaning and weather-resistant coating on the surface of the corona-treated aluminum alloy frame. After spraying, heat up to 110 °C, dry and cure for 20 min, and form a self-cleaning and weather-resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame to obtain a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame.

[0100] Comparative Example 2. A preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0101] Compared with Comparative Example 1, in this comparative example, a borate chain extender was not prepared, but only 0.18 part by mass of 1,4-butanediol was used instead;

[0102] S1. Prepare an aqueous polyurethane emulsion;

[0103] By weight, mix 1.2 parts of polyethylene glycol and 2.8 parts of polytetrahydrofuran ether glycol, stir evenly, then vacuum dry and dehydrate. Under a nitrogen atmosphere, add 1.2 parts of isocyanate monomer, heat up to 78 °C, stir and react for 3 h, then cool down to 70 °C, continue to add 0.27 part of 1,4-butanediol and 0.0008 part of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and stir and emulsify at high speed to obtain an aqueous polyurethane emulsion with a solid content of 37%;

[0104] S2. Prepare a self - cleaning weather - resistant coating;

[0105] By weight, add 2.5 parts of hydrophobic nano - silica, 0.3 parts of leveling agent and 0.6 parts of defoaming agent to 100 parts of water - borne polyurethane emulsion, stir and shear - mix at high speed, and pass through a 30 - μm sieve to obtain a self - cleaning weather - resistant coating;

[0106] S3. Prepare a self - cleaning weather - resistant aluminum alloy photovoltaic module frame:

[0107] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it. Carry out corona treatment on its surface. When carrying out corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s;

[0108] S32. Spray the self - cleaning weather - resistant coating on the surface of the corona - treated aluminum alloy frame. After spraying, heat up to 110 °C, dry and cure for 20 min, and form a self - cleaning weather - resistant coating with a thickness of 30 μm on the surface of the aluminum alloy frame to obtain a self - cleaning weather - resistant aluminum alloy photovoltaic module frame.

[0109] Comparative Example 3. A preparation method of a self - cleaning weather - resistant aluminum alloy photovoltaic module frame, comprising the following steps:

[0110] Compared with Comparative Example 2, hydrophobic nano - silica is not added in this comparative example;

[0111] S1. Prepare a water - borne polyurethane emulsion;

[0112] By weight, mix 1.2 parts of polyethylene glycol and 2.8 parts of polytetrahydrofuran ether glycol, stir evenly, then vacuum - dry and dehydrate. Under a nitrogen atmosphere, add 1.2 parts of isocyanate monomer, heat up to 78 °C, stir and react for 3 h, then cool down to 70 °C, continue to add 0.27 parts of 1,4 - butanediol and 0.0008 parts of dibutyltin dilaurate, continue to stir and react for 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and stir and emulsify at high speed to obtain a water - borne polyurethane emulsion with a solid content of 37%;

[0113] S2. Prepare a self - cleaning weather - resistant coating;

[0114] By weight, add 0.3 parts of leveling agent and 0.6 parts of defoaming agent to 100 parts of water - borne polyurethane emulsion, stir and shear - mix at high speed, and pass through a 30 - μm sieve to obtain a self - cleaning weather - resistant coating;

[0115] S3. Prepare a self - cleaning weather - resistant aluminum alloy photovoltaic module frame:

[0116] S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively, and then dry it. Carry out corona treatment on its surface. When performing corona treatment, the voltage is 15 kV, the power is 1 kW, and the treatment speed is 5 m / s.

[0117] S32. Spray a self-cleaning weather-resistant coating on the surface of the aluminum alloy frame after corona treatment. After spraying, heat it up to 110 °C and dry and cure for 20 min. A self-cleaning weather-resistant coating with a thickness of 30 μm is formed on the surface of the aluminum alloy frame, and a self-cleaning weather-resistant aluminum alloy photovoltaic module frame is obtained.

[0118] Detection: Use a water contact angle measuring instrument to detect the water contact angle of the aluminum alloy photovoltaic module frames prepared in Examples 1-5 and Comparative Examples 1-3.

[0119] Conduct abrasion resistance detection on the aluminum alloy photovoltaic module frames prepared in Examples 1-5 and Comparative Examples 1-3 according to GB / T 22374-2018 "Floor Coating Materials". After rubbing 500 times under a load of 750 g, detect the mass loss.

[0120] Conduct a 800 h artificial aging resistance performance detection on the surface coatings of the aluminum alloy photovoltaic module frames prepared in Examples 1-5 and Comparative Examples 1-3 according to JG / T 172-2005 "Elastomeric Building Coatings".

[0121] Immerse the aluminum alloy photovoltaic module frames prepared in Examples 1-5 and Comparative Examples 1-3 in a salt water with a temperature of 25 ± 2 °C and a concentration of 0.5 mol / L for 96 h, and detect their salt resistance.

[0122] Use a knife to scratch the surface coatings of the aluminum alloy photovoltaic module frames prepared in Examples 1-5 and Comparative Examples 1-3 to make scratches with a length of 30 mm and a depth reaching the aluminum alloy metal part. After standing at room temperature for 15 min, immerse them in a salt water with a temperature of 25 ± 2 °C and a concentration of 0.5 mol / L for 96 h again, and detect their salt resistance.

[0123] The test results are shown in the following table;

[0124]

[0125] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method for a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame, characterized in that, It includes the following steps: S1. Prepare an aqueous polyurethane emulsion; Mix fluorinated polyol and polytetrahydrofuran ether diol, stir evenly, then conduct vacuum drying for dehydration. Under a nitrogen atmosphere, add isocyanate monomer, heat up to 70 - 80 °C, stir and react for 2 - 4 h, then cool down to 60 - 70 °C. Continuously add borate chain extender, small molecule chain extender, and dibutyltin dilaurate, continue to stir and react for 2 - 3 h, then add triethylamine to neutralize and form a salt. After detecting that the pH value is 6.8 - 7.2, add deionized water and conduct high-speed stirring for emulsification to obtain an aqueous polyurethane emulsion with a solid content of 35 - 45%; S2. Prepare a self-cleaning weather-resistant coating; Add hydrophobic nano-silica, leveling agent, and defoaming agent to the aqueous polyurethane emulsion, conduct high-speed stirring and shearing for mixing, and pass through a 15 - 30 μm sieve to obtain a self-cleaning weather-resistant coating; S3. Prepare a self-cleaning weather-resistant aluminum alloy photovoltaic module frame: S31. Wash the surface of the aluminum alloy frame with deionized water and anhydrous ethanol respectively and then dry it, and conduct corona treatment on its surface; S32. Spray the self-cleaning weather-resistant coating on the surface of the corona-treated aluminum alloy frame. After spraying, heat up to 105 - 115 °C, dry and cure for 15 - 30 min to form a self-cleaning weather-resistant coating with a thickness of 15 - 45 μm on the surface of the aluminum alloy frame, and obtain a self-cleaning weather-resistant aluminum alloy photovoltaic module frame.

2. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: In step S1, by weight, the mass ratio of the fluorinated polyol, polytetrahydrofuran ether diol, isocyanate monomer, borate chain extender, small molecule chain extender, and dibutyltin dilaurate is (1.2 - 1.7):(2.8 - 3.2):(1.2 - 1.35):(0.6 - 0.9):(0.08 - 0.1):(0.0005 - 0.0008).

3. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: The molecular weight of the polytetrahydrofuran ether diol is 1500 - 2500; the isocyanate monomer is isophorone diisocyanate; the small molecule chain extender is 1,4-butanediol.

4. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: In step S1, the preparation method of the borate chain extender is as follows: Heat DMF to 115 - 120 °C, keep warm for 30 - 90 min, then cool to room temperature. Mix 5-carbamoyl-2-fluorobenzeneboronic acid with DMF, stir evenly, and then dropwise add a DMF solution containing 2-amino-1,3-propanediol drop by drop thereto while continuously stirring. After reacting in the dark at room temperature for 18 - 36 h, dropwise add glycidol thereto again, heat up to 78 - 86 °C, stir and react for 2 - 6 h, and then rotary evaporate to remove the excess solvent to obtain the borate chain extender.

5. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 4, characterized in that: By molar fraction, the molar ratio of 5-carbamoyl-2-fluorobenzeneboronic acid, 2-amino-1,3-propanediol, and glycidol is 1:(0.95 - 1):(1.98 - 2.02).

6. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: In step S1, the preparation method of the fluorinated polyol is as follows: Disperse tetrafluoroterephthalic acid in DMF, add EDC thereto, stir and mix evenly, then dropwise add 1,3-bis(aminopropyl)tetramethyldisiloxane thereto drop by drop. After heating to 115 - 125 °C and stirring for 8 - 16 h, stop heating. After cooling to room temperature, dropwise add the DMF solution containing 10-amino-1-decanol thereto drop by drop. After the dropping is completed, heat up to 95 - 105 °C and continue stirring for 24 - 48 h, then rotary evaporate to remove the excess solvent to obtain the fluorinated polyol.

7. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 6, characterized in that: Calculated by mole fraction, the molar ratio of tetrafluoroterephthalic acid, 1,3-bis(aminopropyl)tetramethyldisiloxane, and 10-amino-1-decanol is (1.85 - 2):1:(1.95 - 2.05).

8. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: In step S2, calculated by weight fraction, the self-cleaning weather-resistant coating is composed of 100 parts of aqueous polyurethane emulsion, 2.5 - 5 parts of hydrophobic nano-silica, 0.2 - 0.35 parts of leveling agent, and 0.4 - 0.8 parts of defoaming agent.

9. The preparation method of a self-cleaning and weather-resistant aluminum alloy photovoltaic module frame according to claim 1, characterized in that: In step S31, during corona treatment, the voltage is 5 - 20 kV, the power is 0.5 - 1.5 kW, and the treatment speed is 1 - 10 m / s.

10. A self-cleaning weather-resistant aluminum alloy photovoltaic module frame prepared by the preparation method according to any one of claims 1 - 9.

Images