Humidity-heat aging-resistant photovoltaic sealant as well as preparation method and application thereof

Abstract

The invention provides a damp-heat aging resistant photovoltaic sealant as well as a preparation method and application thereof. The damp-heat aging resistant photovoltaic sealant is prepared from the following components in parts by weight: 70 to 100 parts of silane modified polyether, 60 to 100 parts of POSS (Polyhedral Oligomeric Silsesquioxane)-based polysilazane, 30 to 50 parts of PPG (Polypropylene Glycol) 1000, 50 to 100 parts of filler, 1 to 3 parts of ultraviolet absorbent, 3 to 5 parts of titanium dioxide, 7 to 14 parts of silane coupling agent and 1 to 4 parts of catalyst. The invention develops a damp-heat aging resistant photovoltaic sealant taking silane modified fluorinated polyether as a matrix. The sealant contains POSS (Polyhedral Oligomeric Silsesquioxane)-based polysilazane. The hydrophobic effect of fluorine-containing groups on the surface of the sealant and the hydrolytic aging resistance of polyorganosilazane are improved, so that the damp-heat aging resistance of the photovoltaic sealant is improved. Experimental results show that after the photovoltaic sealant is subjected to double-85 experiments, the mechanical property retention rate is 90% or above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaics, and particularly relates to a moisture and heat aging resistant photovoltaic sealant, a preparation method and application thereof. BACKGROUND

[0002] Solar power generation has now become one of the fastest growing renewable energy industries, and a large photovoltaic (PV) system composed of multiple PV modules can generate electricity by absorbing solar radiation as a composite entity, and the electricity generation process is clean and renewable. A PV module is composed of multiple components, mainly including a solar cell, a connecting belt, an encapsulating film, glass, a back sheet film, a protective frame, an encapsulating material, a junction box and an external cable, and from the perspective of cost, the encapsulating material contributes about 4% to the total cost of the PV component. However, the chemical and photochemical stability of the encapsulating material is one of the important factors determining the service life of the PV module. It is known that the performance of an unprotected PV cell exposed to the environment will decrease, and moisture and oxygen can cause some cell materials to fail slowly. In addition, economic analysis of PV system equipment shows that extending the service life can significantly reduce the levelized energy cost; and when the efficiency of the PV device decreases, the operating cost does not decrease. Therefore, increasing the service life of the PV component through encapsulation can improve the technical and economic feasibility of the PV system. The sealant can protect the PV component from mechanical damage and external impurities through edge sealing. The sealant can also act as an electrical insulator between adjacent cells or module components, preventing current leakage while bonding all components together.

[0003] However, the performance of the PV sealant, especially for silane-modified polyether PV sealant, is significantly affected by moisture when used in a long-term high-temperature and humid environment, because the presence of moisture causes the hydrolysis of the siloxane macromolecule of the silicone rubber, resulting in the cracking or crosslinking of the entire molecular structure and thus losing the use performance. SUMMARY

[0004] The purpose of the present application is to provide a moisture and heat aging resistant photovoltaic sealant, a preparation method and application thereof, and the photovoltaic sealant in the present application has excellent moisture and heat aging resistance.

[0005] The present application provides a moisture and heat aging resistant photovoltaic sealant, comprising the following components in parts by weight:

[0006] Silane-modified polyether: 70-100 parts, POSS-based polysilazane: 60-100 parts, polypropylene glycol: 30-50 parts, filler: 50-100 parts, ultraviolet absorber: 1-3 parts, titanium white powder: 3-5 parts, silane coupling agent: 7-14 parts, catalyst: 1-4 parts;

[0007] The silane-modified polyether has the structure shown in Formula I:

[0008]

[0009] In Formula II, n is 55-65;

[0010] The POSS-based polysilazane has the structure shown in Formula II:

[0011]

[0012] In Formula II, R is isooctyl, and R1 and R2 are independently selected from methyl or phenyl.

[0013] Preferably, the silane-modified polyether is prepared according to the following steps:

[0014] 1) reacting a fluorinated polyether polyol having the structure of Formula 1 with sodium methoxide to obtain sodium fluorinated polyether diol;

[0015] 2) allylating the sodium fluorinated polyether diol with allyl chloride to obtain an allylated fluorinated polyether having the structure of Formula 2;

[0016] 3) mixing the allylated fluorinated polyether with trimethoxysilane under the condition of a catalyst to obtain a silane-modified polyether;

[0017]

[0018] Preferably, in the step 1), the fluorinated polyether polyol is first subjected to dehydration treatment, and then reacted with sodium methoxide.

[0019] Preferably, the POSS-based polysilazane is prepared according to the following steps:

[0020] reacting an amine propyl isooctyl-substituted T8-POSS having the structure of Formula 3 with R1R2SiCl in a solvent to obtain a POSS-based polysilazane having the structure of Formula II;

[0021]

[0022] Preferably, the ultraviolet light absorber is a benzotriazole-based light absorber.

[0023] Preferably, the silane coupling agent includes 3-aminopropyl trimethoxysilane and vinyl trimethoxysilane.

[0024] The weight fraction of the 3-aminopropyl trimethoxysilane is 5-10 parts, and the weight fraction of the vinyl trimethoxysilane is 2-4 parts.

[0025] Preferably, the filler is light calcium carbonate.

[0026] Preferably, the catalyst is dibutyl tin dilaurate.

[0027] The application provides a preparation method of the moisture and heat aging resistant photovoltaic sealant as described above, and comprises the following steps:

[0028] The silane modified polyether, the POSS based polysilazane, the PPG1000, the filler, the ultraviolet absorber, the titanium white powder, the silane coupling agent and the catalyst are mixed under the stirring in a vacuum condition to obtain the moisture and heat aging resistant photovoltaic sealant.

[0029] The application provides an application of the moisture and heat aging resistant photovoltaic sealant as described above in photovoltaic device sealing.

[0030] The application provides a moisture and heat aging resistant photovoltaic sealant, which comprises the following components in the following proportions by weight: 70-100 parts of silane modified polyether, 60-100 parts of POSS based polysilazane, 30-50 parts of PPG1000, 50-100 parts of filler, 1-3 parts of ultraviolet absorber, 3-5 parts of titanium white powder, 7-14 parts of silane coupling agent and 1-4 parts of catalyst; the silane modified polyether has the structure shown in formula I; in formula II, n is 55-65; the POSS based polysilazane has the structure shown in formula II; in formula II, R is isooctyl, and R2 is methyl or phenyl. The application develops a moisture and heat aging resistant photovoltaic sealant with silane modified fluorinated polyether as a matrix, and the sealant contains POSS based polysilazane. The hydrophobic effect of fluorine-containing groups on the surface of the sealant and the anti-hydrolysis aging performance of polyorganosilazane are improved, so that the moisture and heat aging resistance of the photovoltaic sealant is improved. Experimental results show that the mechanical performance retention rate of the photovoltaic sealant in the application is above 90% after a double 85 experiment. DETAILED DESCRIPTION

[0031] The application provides a moisture and heat aging resistant photovoltaic sealant, which comprises the following components in the following proportions by weight:

[0032] 70-100 parts of silane modified polyether, 60-100 parts of POSS based polysilazane, 30-50 parts of polypropylene glycol, 50-100 parts of filler, 1-3 parts of ultraviolet absorber, 3-5 parts of titanium white powder, 7-14 parts of silane coupling agent and 1-4 parts of catalyst;

[0033] The silane modified polyether has the structure shown in formula I:

[0034]

[0035] In formula II, n is 55-65;

[0036] The POSS based polysilazane has the structure shown in formula II:

[0037]

[0038] In formula II, R is isooctyl, R1 and R2 are independently selected from methyl or phenyl, and in the present application, R1 and R2 can be the same or different.

[0039] In the present application, the weight fraction of the silane-modified polyether is preferably 70-100 parts, more preferably 80-90 parts, such as 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, and preferably a range value with any of the above values as the upper limit or lower limit.

[0040] In the present application, when the material is cured and cross-linked, the fluorine atoms contained in the silane-modified polyether are arranged on the surface of the material, playing a hydrophobic role, but the realization of this function requires special functional groups. The structure of the present application, which is terminated by organosilicon, enables fluorine to form this hydrophobic structure in the photovoltaic adhesive material, thereby realizing the performance of moisture resistance and aging resistance.

[0041] In the present application, the silane-modified polyether has the structure shown in formula I, wherein n is any integer between 55 and 65, such as 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, and preferably a range value with any of the above values as the upper limit or lower limit. The silane-modified polyether is preferably prepared according to the following steps:

[0042] 1) reacting the fluorinated polyether polyol having formula 1 with sodium methoxide to obtain fluorinated polyether diol sodium;

[0043] 2) allylating the fluorinated polyether diol sodium with allyl chloride to obtain allylated fluorinated polyether having formula 2;

[0044] 3) mixing the allylated fluorinated polyether with trimethoxysilane under the action of a catalyst to obtain a silane-modified polyether;

[0045]

[0046] In the present application, the fluorinated polyether polyol having formula 1 is prepared by the method in patent CN201711410414.1 A surface hydrophobic buffer material and its preparation method and application, which will not be described here.

[0047] Preferably, the fluorinated polyether polyol is first subjected to dehydration treatment, and then the dehydrated fluorinated polyether polyol is mixed with sodium methoxide to obtain fluorinated polyether diol sodium.

[0048] In the present application, the temperature of the dehydration treatment is preferably 100-120°C, more preferably 110-115°C, the time of the dehydration treatment is preferably 1-3 hours, more preferably 2 hours, and the dehydration treatment is preferably reduced pressure dehydration.

[0049] In the present application, the molar ratio of the fluorinated polyether polyol to sodium methoxide is preferably 1:(1.9-2.1), more preferably 1:(2-2.05). The temperature of the reaction is preferably 35-45°C, more preferably 40°C, and the time of the reaction is preferably 1-3 hours, more preferably 2 hours.

[0050] After obtaining the sodium fluorinated polyether diol, the present application reacts it with allyl chloride under nitrogen protection, after the reaction is completed, removes the excess allyl chloride under reduced pressure at 80-85°C and dries to obtain the allylated fluorinated polyether having the structure of Formula 2.

[0051] In the present application, the molar ratio of the sodium fluorinated polyether diol to allyl chloride is preferably 1:(1-2.2), more preferably 1:(1.5-2), such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, preferably a range value with any of the above values as the upper limit or lower limit; the temperature of the reaction is preferably 30-40°C, more preferably 35°C, and the time of the reaction is preferably 0.5-2 hours, more preferably 1-1.5 hours.

[0052] After obtaining the allylated fluorinated polyether, the present application mixes and reacts the allylated fluorinated polyether with trimethoxysilane under nitrogen protection and catalyst conditions, after the reaction is completed, removes the unreacted trimethoxysilane and solvent such as isopropyl alcohol in the system under reduced pressure to obtain the silane-modified polyether having the structure of Formula I.

[0053] In the present application, the catalyst is preferably a platinum catalyst, specifically, in an embodiment of the present application, it can be an isopropyl alcohol solution of chloroplatinic acid, and the mass of the catalyst is 3-5% of the mass of the allylated fluorinated polyether, more preferably 3-4%.

[0054] In the present application, the molar ratio of the allylated fluorinated polyether to trimethoxysilane is preferably 1:(2.5-3), such as 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, preferably a range value with any of the above values as the upper limit or lower limit.

[0055] In the present application, the temperature of the reaction is preferably room temperature, such as 20-30°C, and the time of the reaction is preferably 3-5 hours, more preferably 4 hours.

[0056] In the present application, the weight fraction of the POSS-based polysilazane is preferably 60-100 parts, more preferably 70-90 parts, such as 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, and preferably a range having any of the above values as the upper or lower limit.

[0057] In the present application, the T8-POSS polysilazane filler is liquid, and since the molecular structure is basically composed of silicon, carbon and oxygen, it can be mixed with the matrix resin in any proportion according to the principle of similarity. Moreover, the POSS-based polysilazane in the present application decomposes at high temperature to form a protective layer on the surface of the material, and at the same time, the T8-POSS nanoparticles with high temperature resistance also gather on the surface of the material, forming a double protective effect on the material.

[0058] In the present application, the POSS-based polysilazane has the structure shown in Formula II, and is preferably prepared according to the following steps:

[0059]

[0060] The amine propyl isooctyl substituted T8-POSS with the structure of Formula 3 is reacted with R1R2SiCl in a solvent, and after the reaction is completed, the solvent is removed by vacuum distillation to obtain the POSS-based polysilazane with the structure of Formula II.

[0061] In the present application, the compound with the structure of Formula 3 can be a commercially available product, such as a commercially available product with model number AMO270 produced by Hybrid Company. The mass ratio of the compound with the structure of Formula 3 to R1R2SiCl is preferably 1:(6-8), more preferably 1:(6-7).

[0062] In the present application, the reaction temperature is preferably 45-55°C, more preferably 50°C, and the reaction time is preferably 5-7 hours, more preferably 6 hours.

[0063] In the present application, the polypropylene glycol is preferably PPG1000, and the weight fraction of the polypropylene glycol is preferably 30-50 parts, more preferably 35-45 parts.

[0064] In the present application, the filler is preferably light calcium carbonate, and the weight fraction of the filler is preferably 50-100 parts, more preferably 60-90 parts, such as 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, and preferably a range having any of the above values as the upper or lower limit.

[0065] In the present application, the ultraviolet light absorber is preferably a benzotriazole light absorber, such as tinuvin327, and the weight fraction of the ultraviolet light absorber is preferably 1-3 parts, more preferably 1-2 parts.

[0066] In the present application, the weight fraction of the titanium white powder is preferably 3-5 parts, more preferably 3-4 parts.

[0067] In the present application, the silane coupling agent preferably includes 3-aminopropyl trimethoxysilane (KH-540) and vinyl trimethoxysilane (A-171); the weight fraction of the 3-aminopropyl trimethoxysilane is preferably 5-10 parts, more preferably 6-9 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, preferably a range value above or below any of the above values as the upper or lower limit, and the weight fraction of the vinyl trimethoxysilane is preferably 2-4 parts, more preferably 2-3 parts.

[0068] In the present application, the catalyst is preferably dibutyl tin dilaurate, and the weight fraction of the catalyst is preferably 1-4 parts, more preferably 2-3 parts.

[0069] The present application also provides a preparation method of the moisture and heat aging resistant photovoltaic sealant as described above, comprising the following steps:

[0070] The silane modified polyether, POSS based polysilazane, PPG1000, filler, ultraviolet absorber, titanium white powder, silane coupling agent and catalyst are mixed under vacuum stirring to obtain the moisture and heat aging resistant photovoltaic sealant.

[0071] Preferably, the present application adds silane modified polyether, POSS based polysilazane, polypropylene glycol, filler, ultraviolet light absorber, titanium white powder and A-171 into a mechanical stirrer, stirs under vacuum at 75-80℃ for 1-2 hours, then cools to below 40℃, adds catalyst and KH-540, stirs for 0.5-1 hour, and seals and packages.

[0072] The present application also provides an application of the moisture and heat aging resistant photovoltaic sealant as described above in photovoltaic device sealing, or as an electrical insulator between adjacent cells or module components, which prevents current leakage while bonding all components together.

[0073] The application provides a moisture and heat aging resistant photovoltaic sealant, which comprises the following components in parts by weight: silane modified polyether: 70-100 parts, POSS based polysilazane: 60-100 parts, PPG1000: 30-50 parts, filler: 50-100 parts, ultraviolet absorber: 1-3 parts, titanium white: 3-5 parts, silane coupling agent: 7-14 parts, and catalyst: 1-4 parts; the silane modified polyether has the structure shown in formula I: in formula II, n is 55-65; the POSS based polysilazane has the structure shown in formula II: in formula II, R is isooctyl, and R2 is methyl or phenyl. The application develops a moisture and heat aging resistant photovoltaic sealant with silane modified fluorinated polyether as a matrix, and the sealant contains POSS based polysilazane. The hydrophobic effect of fluorine-containing groups on the surface of the sealant and the water hydrolysis aging resistance of polyorganosilazane are improved, so that the moisture and heat aging resistance of the photovoltaic sealant is improved. Experimental results show that the mechanical property retention rate of the photovoltaic sealant in the application is above 90% after the double-85 experiment.

[0074] In order to further illustrate the application, the moisture and heat aging resistant photovoltaic sealant, the preparation method and the application thereof provided by the application are described in detail below in combination with examples, but it should not be understood as a limitation on the protection scope of the application.

[0075] Sealant test sample preparation method: the sealant is injected into a mold, and the two sides are scraped flat with a scraper, the thickness of the adhesive layer is 1.8-2.0 mm, and the adhesive sheet is taken out and cut into corresponding dumbbell-shaped test pieces after curing for 7 days under standard conditions (temperature is 23±2 ℃, relative humidity is 50±5%). The tensile strength and elongation at break are tested by a universal tensile testing machine.

[0076] Moisture and heat aging resistance test method:

[0077] Moisture and heat aging resistance test (double-85 test): after the sealant test piece is cured for 7 days, it is placed in a constant temperature and humidity test chamber with a temperature of 85 ℃ and a relative humidity of 85% for aging for 1000 h, and then the mechanical properties and changes thereof are tested according to standards GB / T 528-2009 and GB / T 531-2008.

[0078] Example 1

[0079] The preparation process of the silane modified fluorinated polyether is as follows:

[0080] 1) Preparation of fluorinated polyether glycol sodium, first, the fluorinated polyether glycol is subjected to dehydration treatment, 500 g of fluorinated polyether glycol is weighed, and dehydration is carried out at 110 ℃ for 2 h under reduced pressure. The round-bottom flask containing the dehydrated fluorinated polyether glycol is taken out, and after it is naturally cooled to room temperature, 20 g of sodium methoxide is added, and the reaction is carried out at 40 ℃ for 2 h, and then the temperature is cooled to room temperature.

[0081] 2) Allylation reaction, take 300g of the alkoxide of fluorinated polyether diol, under the protection of nitrogen, react with 30g of allyl chloride at 35℃ for 1h, after the reaction is completed, dry by removing excess allyl chloride at 80℃ under reduced pressure.

[0082] 3) Take 200g of the allylated fluorinated polyether and place it in a three-necked flask, protect it by passing nitrogen, add 1g of platinum catalyst (isopropanol solution of chloroplatinic acid) and 100g of trimethoxysilane, react at room temperature for 4h. After the reaction is completed, remove the unreacted trimethoxysilane and isopropanol in the flask under reduced pressure, and a light yellow silane-modified fluorinated polyether (GPC method for determining the number average molecular weight is 5600, viscosity is 4500mpas, 25℃) is obtained.

[0083] The preparation process of the POSS-based polysilazane is as follows:

[0084] Add amine propyl isooctyl substituted T8-POSS 4 (produced by Hybrid Company, product number AMO270) and diphenyl (methyl) dichlorosilane (6-8 times the mass of compound 4) into the reaction container, mix them uniformly with acetone, then increase the temperature of the reaction system to 50℃, react for 6h, and remove the acetone under reduced pressure to obtain a light yellow amine propyl isooctyl substituted T8-POSS-based polysilazane (GPC method for determining the number average molecular weight is 11000, viscosity is 3500mpas, 25℃).

[0085] According to mass, add 70 parts of silane-modified polyether, 60 parts of POSS-based polysilazane, 30 parts of PPG1000, 50 parts of light calcium carbonate, 1 part of tinuvin 327, 3 parts of titanium white, and 2 parts of A-171 into a mechanical stirrer, stir at 80℃ under vacuum for 2h, then cool it to below 40℃, add 1 part of dibutyltin dilaurate and 5 parts of KH-540, stir for 0.5h, seal and package, then pour it into a mold, use a spatula to scrape the two sides flat, the thickness of the glue layer is 1.8-2.0mm, and after curing for 7 days under standard conditions (temperature is 23±2℃, relative humidity is 50±5%), take out the glue sheet and cut it into corresponding dumbbell-shaped test pieces, conduct a wet heat aging test, and use a universal testing machine to test the tensile strength and elongation at break before and after the wet heat aging. The specific results are shown in Table 1.

[0086] Example 2

[0087] Use the silane-modified polyether and the POSS-based polysilazane prepared in Example 1.

[0088] By mass, 70 parts of silane modified polyether, 70 parts of POSS based polysilazane, 35 parts of PPG1000, 60 parts of light calcium carbonate, 2 parts of tinuvin 327, 3 parts of titanium white powder, 2 parts of A-171 were added into a mechanical stirrer, stirred at 80°C under vacuum for 2h, then cooled to below 40°C, 1 part of dibutyltin dilaurate and 5 parts of KH-540 were added, stirred for 0.5h, sealed and packaged, then poured into a mold, the two sides were scraped flat with a spatula, the glue layer thickness was 1.8-2.0mm, cured for 7 days under standard conditions (temperature was 23±2°C, relative humidity was 50±5%), the glue sheet was taken out and cut into corresponding dumbbell-shaped test pieces, and the tensile strength and elongation at break before and after wet heat aging were tested by using a universal testing machine. The specific results are shown in Table 1.

[0089] Example 3

[0090] The silane modified polyether and POSS based polysilazane prepared in Example 1 were used.

[0091] By mass, 80 parts of silane modified polyether, 90 parts of POSS based polysilazane, 50 parts of PPG1000, 80 parts of light calcium carbonate, 3 parts of tinuvin 327, 5 parts of titanium white powder, 4 parts of A-171 were added into a mechanical stirrer, stirred at 80°C under vacuum for 2h, then cooled to below 40°C, 2 parts of dibutyltin dilaurate and 6 parts of KH-540 were added, stirred for 0.5h, sealed and packaged, then poured into a mold, the two sides were scraped flat with a spatula, the glue layer thickness was 1.8-2.0mm, cured for 7 days under standard conditions (temperature was 23±2°C, relative humidity was 50±5%), the glue sheet was taken out and cut into corresponding dumbbell-shaped test pieces, and the tensile strength and elongation at break before and after wet heat aging were tested by using a universal testing machine. The specific results are shown in Table 1.

[0092] Example 4

[0093] The silane modified polyether and POSS based polysilazane prepared in Example 1 were used.

[0094] By mass, 90 parts of silane modified polyether, 90 parts of POSS based polysilazane, 50 parts of PPG1000, 80 parts of light calcium carbonate, 3 parts of tinuvin 327, 5 parts of titanium white, 4 parts of A-171 were added into a mechanical stirrer, stirred at 80°C under vacuum for 2h, then cooled to below 40°C, 3 parts of dibutyltin dilaurate and 8 parts of KH-540 were added, stirred for 0.5h, sealed and packaged, then poured into a mold, the two sides were scraped flat with a spatula, the glue layer thickness was 1.8-2.0mm, cured for 7 days under standard conditions (temperature was 23±2°C, relative humidity was 50±5%), the glue sheet was taken out and cut into corresponding dumbbell-shaped test pieces, and the tensile strength and elongation at break before and after wet heat aging were tested by using a universal testing machine. The specific results are shown in Table 1.

[0095] Example 5

[0096] The silane modified polyether and POSS based polysilazane prepared in Example 1 were used.

[0097] By mass, 90 parts of silane modified polyether, 90 parts of POSS based polysilazane, 50 parts of PPG1000, 80 parts of light calcium carbonate, 3 parts of tinuvin 327, 5 parts of titanium white, 4 parts of A-171 were added into a mechanical stirrer, stirred at 80°C under vacuum for 2h, then cooled to below 40°C, 3 parts of dibutyltin dilaurate and 8 parts of KH-540 were added, stirred for 0.5h, sealed and packaged, then poured into a mold, the two sides were scraped flat with a spatula, the glue layer thickness was 1.8-2.0mm, cured for 7 days under standard conditions (temperature was 23±2°C, relative humidity was 50±5%), the glue sheet was taken out and cut into corresponding dumbbell-shaped test pieces, and the tensile strength and elongation at break before and after wet heat aging were tested by using a universal testing machine. The specific results are shown in Table 1.

[0098] Example 6

[0099] The silane modified polyether and POSS based polysilazane prepared in Example 1 were used.

[0100] According to the mass, 100 parts of silane modified polyether, 100 parts of POSS based polysilazane, 50 parts of PPG1000, 100 parts of light calcium carbonate, 3 parts of tinuvin 327, 5 parts of titanium white, 4 parts of A-171 are added into a mechanical stirrer, vacuum 80℃ stirring for 2h, then cooling to below 40℃, adding 4 parts of dibutyltin dilaurate and 10 parts of KH-540, stirring for 0.5h, sealing and packaging, then pouring into a mold, using a scraper to scrape the two sides flat, the glue layer thickness is 1.8-2.0mm, curing for 7 days under standard conditions (temperature is 23±2℃, relative humidity is 50±5%), taking out the glue sheet and cutting into corresponding dumbbell-shaped test pieces, carrying out wet heat aging test, using a universal testing machine to test the tensile strength and elongation at break before and after wet heat aging. The specific results are shown in Table 1.

[0101] Table 1 Performance data of sealant in the examples and comparative examples of the present application

[0102]

[0103]

[0104] From the data in Table 1, it can be seen that the photovoltaic sealant in the present application has a high mechanical property retention rate before and after the wet heat experiment, while the sealant in the prior art, such as the reference document He Yiming, Zhang Yinhua, Su Shaojun. Development of high-strength wet heat aging resistant room temperature vulcanized silicone rubber [J]. Organic silicon materials, 2012, 26(4): 6. DOI: 10.3969 / j.issn.1009-4369.2012.04.005, has a tensile strength retention rate of at most 80% after wet heat aging, and the mechanical property retention rate is usually only 60-70%.

[0105] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A photovoltaic sealant resistant to moisture and heat aging, comprising the following components in parts by weight: Silane-modified polyether: 70-100 parts, POSS-based polysilazane: 60-100 parts, polypropylene glycol: 30-50 parts, filler: 50-100 parts, UV absorber: 1-3 parts, titanium dioxide: 3-5 parts, silane coupling agent: 7-14 parts, catalyst: 1-4 parts. The silane-modified polyether has the structure shown in Formula I: In Equation II, n is 55 to 65; The POSS-based polysilazane has the structure shown in Formula II: In Formula II, R is isooctyl, and R1 and R2 are independently selected from methyl or phenyl.

2. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The silane-modified polyether was prepared according to the following steps: 1) A fluorinated polyether polyol having the structure of Formula 1 is reacted with sodium methoxide to obtain sodium fluorinated polyether diol; 2) The sodium fluorinated polyether glycol is subjected to an allylation reaction with allyl chloride to obtain an allylated fluorinated polyether having the structure of Formula 2; 3) Under catalytic conditions, allylated fluorinated polyether is mixed and reacted with trimethoxysilane to obtain silane-modified polyether; 3. The photovoltaic sealant resistant to damp heat aging according to claim 2, characterized in that, In step 1), the fluorinated polyether polyol is first dehydrated and then reacted with sodium methoxide.

4. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The POSS-based polysilazane was prepared according to the following steps: T8-POSS with aminopropyl isooctyl substituted structure of formula 3 was reacted with R1R2SiCl in a solvent to obtain POSS-based polysilazane with structure of formula II.

5. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The ultraviolet light absorber is a benzotriazole-based light absorber.

6. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The silane coupling agent includes 3-aminopropyltrimethoxysilane and vinyltrimethoxysilane; The 3-aminopropyltrimethoxysilane is present in 5 to 10 parts by weight, and the vinyltrimethoxysilane is present in 2 to 4 parts by weight.

7. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The filler is light calcium carbonate.

8. The photovoltaic sealant resistant to damp heat aging according to claim 1, characterized in that, The catalyst is dibutyltin dilaurate.

9. The preparation method of the photovoltaic sealant resistant to damp heat aging as described in claim 1, comprising the following steps: Silane-modified polyether, POSS-based polysilazane, PPG1000, filler, UV absorber, titanium dioxide, silane coupling agent and catalyst were stirred and mixed under vacuum to obtain a photovoltaic sealant resistant to humid heat aging.

10. The application of the moisture- and heat-resistant photoresist as described in any one of claims 1 to 8 in the sealing of photovoltaic devices.

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