An ultra-low water vapor transmission rate photovoltaic module sealant and a preparation method thereof

Abstract

The application relates to the technical field of sealing material preparation, in particular to a photovoltaic module sealing glue with ultra-low water vapor transmission rate and a preparation method thereof, which at least comprises the following components in parts by weight: 4-10 parts of high molecular rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, 7-15 parts of silane modified resin, 15-20 parts of reinforcing filler, 30-40 parts of extending filler, 3-8 parts of drier, 0.3-1 part of antioxidant and 0.3-1 part of ultraviolet stabilizer; the sealing glue has very low water vapor transmission rate, can more effectively prevent water vapor from corroding solar cell pieces, has excellent aging resistance and processing performance, and thus the photoelectric conversion efficiency and service life of the solar cell pieces are improved.

Description

Technical Field

[0001] This invention relates to the field of sealing material preparation technology, specifically to a photovoltaic module sealant with ultra-low water vapor transmission rate and its preparation method. Background Technology

[0002] A photovoltaic (PV) module is a device that converts solar energy into electrical energy, with solar cells as its core component. To protect the solar cells and improve their photoelectric conversion efficiency, a transparent encapsulation material is applied to their surface. This material is typically made of materials such as ethylene-vinyl acetate copolymer (EVA), polyethylene terephthalate (PET), or glass. For moisture-sensitive cells like HJTs (heterojunction cells), a waterproof and moisture-proof sealant is applied to the outside of the encapsulation material to prevent moisture corrosion. Currently, the main sealants for PV modules are silicone sealants and polyurethane sealants. Both sealants offer some waterproof and moisture-proof properties, effectively protecting the solar cells. However, their relatively high water vapor permeability means they cannot completely prevent moisture corrosion, leading to a decrease in the solar cells' photoelectric conversion efficiency.

[0003] Chinese patent application (publication number CN118599471A) discloses a double-glass module frame sealant and its preparation method. The method involves introducing at least one of silane-modified kaolin, mica powder, glass microspheres, and modified wollastonite into the system, along with polyolefin A and polyolefin B, to achieve a water vapor permeability of ≤5 g / m³. 2 0.24h). Chinese patent application (publication number CN118440625A) discloses a sealant and its preparation method. By compounding polyisobutylene of different molecular weights with butyl rubber, the initial tack, adhesive strength, and bulk strength of the polymer are increased. The addition of specially compounded molecular sieves and silane-terminated polymers enables efficient water vapor barrier through a combination of physical and chemical methods, reducing the water vapor permeability of the provided product to 0.05 (g / m²). 2 However, in practical applications, there may still be issues such as high water vapor permeability, insufficient aging performance, and lamination puncture problems.

[0004] Therefore, how to develop a sealant with extremely low water vapor permeability and excellent aging resistance to improve the photoelectric conversion efficiency and lifespan of solar cells is an important issue currently facing photovoltaic module manufacturing technology. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a photovoltaic module sealant with ultra-low water vapor transmission rate. This sealant has extremely low water vapor transmission rate, which can more effectively prevent water vapor from corroding solar cells. It also has excellent aging resistance and processing performance, thereby improving the photoelectric conversion efficiency and lifespan of solar cells.

[0006] The present invention provides a photovoltaic module sealant with ultra-low water vapor transmission rate. By weight, the raw materials for its preparation include at least: 2-10 parts of high molecular weight rubber or resin, 20-35 parts of medium molecular weight polyisobutylene, 5-15 parts of silane-modified resin, 15-25 parts of reinforcing filler, 20-50 parts of incremental filler, 1-15 parts of desiccant, 0-2 parts of antioxidant, and 0-2 parts of ultraviolet stabilizer.

[0007] Preferably, the raw materials for preparing the ultra-low water vapor transmission rate photovoltaic module sealant include, by weight, at least: 4-10 parts of high molecular weight rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, 7-15 parts of silane-modified resin, 15-20 parts of reinforcing filler, 30-40 parts of additive filler, 3-8 parts of desiccant, 0.3-1 part of antioxidant, and 0.3-1 part of UV stabilizer.

[0008] Preferably, the raw materials for preparing the ultra-low water vapor transmission rate photovoltaic module sealant include, by weight, at least: 4-7 parts of high molecular weight rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, 7-10 parts of silane-modified resin, 15-20 parts of reinforcing filler, 31-38 parts of additive filler, 5-8 parts of desiccant, 0.3-0.5 parts of antioxidant, and 0.5-0.7 parts of UV stabilizer.

[0009] As a preferred technical solution, the polymer rubber or resin is selected from at least one of ethylene propylene diene monomer (EPDM), linear low-density polyethylene (LLDPE), butyl rubber (IIR), polyisobutylene rubber (PIB), polyolefin elastomer (POE), polybutadiene rubber (PBR), polyisoprene (PI), and SBS thermoplastic elastomer.

[0010] Preferably, the polymer rubber or resin is selected from one of ethylene propylene diene monomer (EPDM), linear low-density polyethylene (LLDPE), butyl rubber (IIR), polyisobutylene rubber (PIB), and polyolefin elastomer (POE).

[0011] As a preferred technical solution, the Mooney viscosity (ML1+8, 125℃, ASTM D1646 (mod)) of the butyl rubber (IIR) is 40-60 MU, preferably 46-56 MU.

[0012] As a preferred technical solution, the Mooney viscosity (ML1+4, 125℃, ASTM D1646 (mod)) of the EPDM rubber is 10-30 MU, preferably 15-25 MU.

[0013] As a preferred technical solution, the viscosity-average molecular weight (Mv) of the polyisobutylene rubber (PIB) is 300,000 to 1,500,000, preferably 500,000 to 1,300,000.

[0014] As a preferred technical solution, the melt flow index (MFR, GB / T3682) of the linear low-density polyethylene (LLDPE) is 1-3 g / 10 min, preferably 1.5-2.5 g / 10 min.

[0015] As a preferred technical solution, the polyolefin elastomer (POE) has a Shore hardness ≥80A, and is preferably at least one of DF805, DF810, DF820, DF840, DF910, DF940, and DF110.

[0016] As a preferred technical solution, the viscosity-average molecular weight (Mv) of the medium molecular weight polyisobutylene is 30,000 to 150,000, preferably 40,000 to 90,000.

[0017] As an example, the viscosity-average molecular weight (Mv) of the medium molecular weight polyisobutylene can be 4±0.2 million, 4.5±0.2 million, 5±0.2 million, 5.5±0.2 million, 6±0.2 million, 6.5±0.2 million, 7±0.2 million, 7.5±0.2 million, 8±0.2 million, 8.5±0.2 million, or 9±0.2 million.

[0018] As a preferred technical solution, the silane-modified resin includes at least one of silane-modified polyolefin, silane-modified polyisobutylene, silane-grafted PE, and silane-modified polybutadiene.

[0019] Preferably, the silane-modified polyolefin comprises a silane-modified α-olefin copolymer.

[0020] Preferably, the softening point (ring and ball method) of the silane-modified polyolefin is >90°C and the penetration is <25 (100 / 25 / 5, 0.1 mm).

[0021] As a preferred technical solution, the reinforcing filler is selected from at least one of fumed silica, precipitated silica, and carbon black, and the original particle size of the reinforcing filler is >30nm.

[0022] Preferably, the reinforcing filler is carbon black or a combination of carbon black and at least one of fumed silica, precipitated silica, and carbon black.

[0023] Preferably, the reinforcing filler is carbon black.

[0024] Preferably, the reinforcing filler is semi-reinforcing carbon black, which is selected from at least one of EBORI N776, N772, N774, and N770.

[0025] This invention balances the reinforcing and thickening effects by introducing semi-reinforcing carbon black and controlling its addition amount. The proportion of reinforcing filler should not be too high, as this will lead to excessive thickening and affect processing performance.

[0026] As a preferred technical solution, the particle size of the incremental filler is ≥1250 mesh, preferably 2000-6000 mesh, and most preferably 2000-3000 mesh.

[0027] Preferably, the incremental filler is selected from at least one of light calcium carbonate, talc, kaolin, heavy calcium carbonate, silica powder, mica powder, quartz powder, and organobentonite.

[0028] Preferably, the incremental filler is selected from at least one of light calcium carbonate, talc, kaolin, and heavy calcium carbonate.

[0029] Preferably, the incremental filler is any one of light calcium carbonate, talc, kaolin, and heavy calcium carbonate.

[0030] The desiccant is selected from at least one of silica gel, anhydrous calcium chloride, anhydrous magnesium sulfate, montmorillonite, magnesium oxide, anhydrous calcium sulfate, 3A molecular sieve, and 4A molecular sieve.

[0031] As a preferred technical solution, the desiccant is selected from at least one of silica gel, magnesium oxide, anhydrous calcium sulfate, 3A molecular sieve, and 4A molecular sieve.

[0032] Preferably, the desiccant is any one of silica gel, magnesium oxide, anhydrous calcium sulfate, 3A molecular sieve, and 4A molecular sieve.

[0033] As a preferred technical solution, the antioxidant and the UV stabilizer are both selected from one of hindered phenols, phosphate esters, mercapto compounds, benzotriazoles, and benzophenones.

[0034] Preferably, the antioxidant is antioxidant 1010 or antioxidant BHT.

[0035] Preferably, the ultraviolet stabilizer is ultraviolet stabilizer UV234 or ultraviolet stabilizer UV770.

[0036] This invention provides a photovoltaic module sealant with ultra-low water vapor transmission rate. By optimizing the product system, which includes specific polymer rubber or resin combined with medium molecular weight polyisobutylene and silane-modified resin, and with the combined effect of other raw materials, it effectively solves the problem of high water vapor transmission rate in existing photovoltaic module sealants. Simultaneously, it exhibits excellent aging stability, which has significant application value for the development of photovoltaic module manufacturing industries such as HJT and perovskite cells. It can be widely used in building vacuum insulation, waterproof and moisture-proof design of electronic equipment, and improve product reliability and service life. Specifically, by optimizing the ratio of polymer rubber or resin to medium molecular weight polyisobutylene and silane-modified resin in the sealant, the provided product simultaneously possesses extremely low water vapor transmission rate, higher adhesive strength and peel strength, with a water vapor transmission rate ≤0.025g / (m²). 2 With a bonding strength ≥0.4MPa and a peel strength ≥25N / cm, it better meets the needs of practical applications. In particular, by controlling the sealant system to include 4-10 parts of high molecular weight rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, and 7-15 parts of silane-modified resin, the product has suitable melt index and hardness while ensuring the above properties. This makes it easier to maintain the tightness of the sealant strip in contact with the photovoltaic glass surface during lamination, greatly reducing the occurrence of punctures during lamination. It is more suitable for automated glue application processes. When hot-pressing with EVA or POE film, it significantly improves the puncture problem during lamination, making it more widely applicable in photovoltaic module manufacturing.

[0037] Furthermore, based on the system of this invention, by selecting suitable carbon black and introducing antioxidant 1010 or antioxidant BHT in combination with UV stabilizer UV234 or UV stabilizer UV770, the aging resistance of the product is guaranteed, providing better reliability and long-term protection for photovoltaic modules.

[0038] Another aspect of the present invention provides a method for preparing a photovoltaic module sealant with ultra-low water vapor transmission rate, comprising at least the following steps: preheating a kneader to a set temperature, adding 40-60 wt% of polymer rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading; adding the remaining medium molecular weight polyisobutylene, silane-modified resin, additive filler, desiccant, antioxidant, and UV stabilizer for kneading to obtain the final product.

[0039] Preferably, the set temperature is 150-170℃ and the pre-kneading time is 0.5-1.5h.

[0040] Preferably, the kneading includes: kneading at a temperature of 150-170℃ for 0.5-1.5h, and then kneading at a temperature of 150-170℃ and a vacuum degree of -0.095MPa for 1-3h.

[0041] The ultra-low water vapor transmission rate photovoltaic module sealant provided by this invention, based on the selection of each raw material in the system, first preheats the kneader to 150-170℃ and adds 40-60wt% of the total amount of polymer rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading, and then adds other raw materials for kneading and vacuum kneading, further ensuring the bonding performance and aging resistance of the product, so that the provided product can maintain its performance in various harsh environments, thereby ensuring the normal operation of solar cells and extending their service life.

[0042] Beneficial effects 1. This invention provides a photovoltaic module sealant with ultra-low water vapor transmission rate. It has extremely low water vapor transmission rate, which can more effectively prevent water vapor from corroding the solar cell. At the same time, it has excellent aging resistance and processing performance, thereby improving the photoelectric conversion efficiency and service life of the solar cell.

[0043] 2. The photovoltaic module sealant provided by this invention, through the optimization of the product system including specific polymer rubber or resin combined with medium molecular weight polyisobutylene and silane modified resin, and with the combined effect of other raw materials, effectively solves the problem of high water vapor permeability of existing photovoltaic module sealants, while having excellent aging stability. It has important application value for the development of photovoltaic module manufacturing industries such as HJT and perovskite cells, and can be widely used in building vacuum insulation, waterproof and moisture-proof design of electronic equipment, and improve the reliability and service life of products.

[0044] 3. This invention optimizes the ratio of high molecular weight rubber or resin to medium molecular weight polyisobutylene and silane-modified resin in the sealant, resulting in a product that simultaneously exhibits extremely low water vapor transmission rate, higher adhesive strength, and peel strength. The water vapor transmission rate of the product is ≤0.025 g / (m²). 2 •day), with an adhesive strength ≥0.4MPa and a peel strength ≥25N / cm, better meeting the needs of practical applications.

[0045] 4. By controlling the composition of the sealant system to include 4-10 parts of high molecular weight rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, and 7-15 parts of silane-modified resin, this invention ensures the aforementioned properties while providing a product with suitable melt index and hardness. This makes it easier to maintain the tightness of the sealant strip in contact with the photovoltaic glass surface during lamination, greatly reducing the occurrence of punctures during lamination. It is more suitable for automated sealing processes and significantly improves the puncture problem during lamination when hot-pressing with EVA or POE films, thus giving it a wider range of application prospects in photovoltaic module manufacturing.

[0046] 5. The photovoltaic module sealant provided by this invention, based on the selection of each raw material in the system, first preheats the kneader to 150-170℃ and adds 40-60wt% of the total amount of high molecular weight rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading, and then adds other raw materials for kneading and vacuum kneading, to further ensure the bonding performance and aging resistance of the product, so that the provided product can maintain its performance in various harsh environments, thereby ensuring the normal operation of solar cells and extending their service life. Attached Figure Description

[0047] Figure 1 The image shows a sample of the sealant provided in Example 4 before undergoing a PCT aging test.

[0048] Figure 2 The image shows a sample of the sealant provided in Example 4 after PCT aging test.

[0049] Figure 3 The image shows a sample of the sealant provided in Comparative Example A after PCT aging test. Detailed Implementation

[0050] The types and sources of each raw material in the embodiments and comparative examples of this invention are shown in Table 1.

[0051] Table 1

[0052] Examples 1-5, Comparative Examples 1-4 Examples 1-5 and Comparative Examples 1-4 of the present invention provide a photovoltaic module sealant with ultra-low water vapor transmission rate. The raw materials for its preparation are shown in Table 2 by weight.

[0053] Table 2

[0054] Examples 1-5 and Comparative Examples 1, 3, and 4 of the present invention provide a method for preparing a photovoltaic module sealant with ultra-low water vapor transmission rate, comprising the following steps: preheating a kneader to a set temperature, adding 50 wt% of the total amount of polymer rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading; adding the remaining medium molecular weight polyisobutylene, silane-modified resin, additive filler, desiccant, antioxidant, and UV stabilizer for kneading to obtain the sealant.

[0055] The set temperature is 160℃, and the pre-kneading time is 1 hour.

[0056] The kneading process includes kneading at 160°C for 1 hour, and then kneading at 160°C and a vacuum of -0.095 MPa for 2 hours.

[0057] Comparative Example 2 of the present invention provides a method for preparing a photovoltaic module sealant with ultra-low water vapor transmission rate, comprising the following steps: preheating a kneader to 175°C, adding 50 wt% of the total amount of polymer rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading for 1 hour; adding the remaining medium molecular weight polyisobutylene, silane-modified resin, additive filler, desiccant, antioxidant, and UV stabilizer for kneading to obtain the sealant. The vacuum kneading conditions include: time of 2 hours, temperature of 175°C, and vacuum degree of -0.095 MPa.

[0058] Comparative Example A is the mainstream photovoltaic sealant currently on the market, HelioSeal PVS 101 from Fuller China.

[0059] Performance testing The products provided in the examples and comparative examples were subjected to the tests listed in Table 3. The test standards and results are shown in Table 3. Images of the sealant provided in Example 4 before the PCT aging test are also available. Figure 1 See the images of the sealants provided in Example 4 and Comparative Example A after PCT aging tests. Figure 2 , Figure 3 .

[0060] Table 3

[0061] Note: The cobalt chloride test paper color-changing glass sealant was prepared as follows: A 1.5mm thick and 8mm wide strip of sealant was applied around the perimeter of the photovoltaic glass surface. Cobalt chloride color-changing indicator paper was sandwiched between two layers of high-transparency EVA film and laid flat on the photovoltaic glass surface. The top cover was placed opposite the photovoltaic glass, and the edges were secured with tape. After lamination and sealing according to the set procedure, the sealing tape was removed after the sealant cooled. A PCT aging test was then conducted at 105℃ for 500 hours after 24 hours.

[0062] Based on the data in Table 3, it can be seen that the products provided in Examples 1-5 have suitable melt flow index and hardness (relatively low melt flow index, relatively high hardness), and the water vapor transmission rate of the products is ≤0.025g / (m²). 2 • day), bond strength ≥ 0.4 MPa, peel strength ≥ 25 N / cm, PCT aging 500h qualified. The ratio of polymeric rubber or resin to medium molecular weight polyisobutylene and silane-modified resin in Comparative Examples 1, 3, and 4 was changed compared to Examples 1-5, resulting in varying degrees of decrease in the product's properties; the process change in Comparative Example 2 compared to Examples 1-5 led to a decrease in the product's bonding performance and aging resistance. The products provided in Examples 1-5 have improved water vapor permeability, bonding performance, and aging resistance compared to commercially available products (Comparative Example A).

Claims

1. A photovoltaic module sealant with ultra-low water vapor transmission rate, characterized in that, By weight, it consists of the following components: 4-7 parts of high molecular weight rubber or resin, 25-30 parts of medium molecular weight polyisobutylene, 7-10 parts of silane-modified resin, 15-20 parts of reinforcing filler, 31-38 parts of incremental filler, 5-8 parts of desiccant, 0.3-0.5 parts of antioxidant, and 0.5-0.7 parts of UV stabilizer. The polymer rubber or resin is selected from one of ethylene propylene diene monomer (EPDM) rubber, linear low-density polyethylene (LDPE), butyl rubber, polyisobutylene rubber, and polyolefin elastomer; the butyl rubber has a Mooney viscosity of 40-60 MU, the EPDM rubber has a Mooney viscosity of 10-30 MU, the polyisobutylene rubber has a viscosity-average molecular weight of 300,000-1,500,000, the linear low-density polyethylene has a melt index of 1-3 g / 10 min, and the polyolefin elastomer has a Shore hardness ≥80A. The viscosity-average molecular weight of the medium molecular weight polyisobutylene is 40,000-90,000. The silane-modified resin includes at least a silane-modified polyolefin; the silane-modified polyolefin has a softening point >90℃ and a penetration <25, in units of 0.1mm. The original particle size of the reinforcing filler is >30nm, and the reinforcing filler is semi-reinforcing carbon black, which is selected from at least one of Yiborui N776, N772, N774 and N770. The particle size of the incremental filler is 2000-3000 mesh; The antioxidant is antioxidant 1010 or antioxidant BHT, and the ultraviolet stabilizer is ultraviolet stabilizer UV234 or ultraviolet stabilizer UV770. The preparation method of the ultra-low water vapor transmission rate photovoltaic module sealant includes the following steps: preheating the kneader to a set temperature, adding 40-60 wt% of high molecular weight rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading; adding the remaining medium molecular weight polyisobutylene, silane-modified resin, additive filler, desiccant, antioxidant, and UV stabilizer for kneading to obtain the final product. The set temperature is 150-170℃, and the pre-kneading time is 0.5-1.5h; The kneading process includes kneading at a temperature of 150-170℃ for 0.5-1.5 hours, and then kneading at a temperature of 150-170℃ and a vacuum of -0.095MPa for 1-3 hours.

2. The photovoltaic module sealant with ultra-low water vapor transmission rate according to claim 1, characterized in that, The desiccant is selected from at least one of silica gel, anhydrous calcium chloride, anhydrous magnesium sulfate, montmorillonite, magnesium oxide, anhydrous calcium sulfate, 3A molecular sieve, and 4A molecular sieve.

3. A method for preparing a photovoltaic module sealant with ultra-low water vapor transmission rate according to any one of claims 1-2, characterized in that, The process includes the following steps: preheating the kneader to the set temperature, adding 40-60 wt% of the total amount of high molecular weight rubber or resin, medium molecular weight polyisobutylene, and reinforcing filler for pre-kneading; adding the remaining medium molecular weight polyisobutylene, silane-modified resin, additive filler, desiccant, antioxidant, and UV stabilizer for kneading to obtain the final product. The set temperature is 150-170℃, and the pre-kneading time is 0.5-1.5h; The kneading process includes kneading at a temperature of 150-170℃ for 0.5-1.5 hours, and then kneading at a temperature of 150-170℃ and a vacuum of -0.095MPa for 1-3 hours.

Images