High-reflection white EVA film and preparation method thereof
The high-reflectivity white EVA film prepared by the three-layer co-extrusion process solves the problems of local short circuit and unstable power generation of the back glass reflective film of photovoltaic modules, achieving high reflectivity and stable power generation gain, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-03
AI Technical Summary
The reflective film on the back glass of existing photovoltaic modules has the risk of local short circuits, resulting in unstable power generation and high production costs. Furthermore, the design of aluminum-plated gap films makes power generation highly susceptible to seasonal fluctuations.
A high-reflectivity white EVA film is prepared using a three-layer co-extrusion process, comprising a low-flow support layer and a white adhesive layer. It is made from materials such as ethylene-vinyl acetate resin, crosslinking agent, silane coupling agent, light stabilizer, antioxidant, and white filler, and is obtained by co-extrusion and slitting. It is suitable for the gaps between photovoltaic module cells and the back glass.
It improves reflectivity, stabilizes power generation gain, reduces production costs, and has excellent insulation performance and aesthetic appeal to customers, while also having a simple manufacturing process.
Smart Images
Figure CN121793518A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photovoltaic technology, and in particular to a high-reflectivity white EVA film and its preparation method. Background Technology
[0002] In recent years, the photovoltaic industry has developed rapidly, and industry requirements have continued to rise. Cost reduction and efficiency improvement have become the focus of major module manufacturers.
[0003] Currently, the mainstream back glass for photovoltaic (PV) modules is either white enamel-coated glass or various reflective gap films applied to the back glass. These films reflect sunlight through the gaps between the solar cells, thereby increasing module power. Among these, aluminized gap films are the most common. These films use an aluminized microstructure to directionally reflect sunlight onto the surface of the solar cells, achieving power gain. However, these films have a chance of causing partial short circuits in the PV module during use, and due to their directional reflection design, their power generation gain is significantly affected by seasonal fluctuations at the end-user level. Their power generation cannot achieve a stable and continuous increase. The multi-stage manufacturing process also results in high costs. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a high-reflectivity white EVA film and its preparation method to solve the above-mentioned problem.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-reflectivity white EVA film, comprising a low-flow support layer, wherein white adhesive layers are respectively connected to both sides of the low-flow support layer, and the white EVA film is applied to the gaps between the photovoltaic module cells, the perimeter of the photovoltaic module, and the back glass of the photovoltaic module.
[0006] As a further embodiment of the present invention, the low-flow support layer, calculated in 100 parts by weight, comprises 0.1-1 parts of crosslinking agent, 0.2-1 parts of silane coupling agent, 0.01-0.2 parts of light stabilizer, 0.01-0.2 parts of antioxidant, 25-50 parts of white filler, 5-15 parts of glass fiber, and the balance being ethylene-vinyl acetate resin.
[0007] As a further embodiment of the present invention, the white adhesive layer, calculated by weight of 100 parts, contains 0.1-1 parts of crosslinking agent, 0.2-1 parts of silane coupling agent, 0.01-0.2 parts of light stabilizer, 0.01-0.2 parts of antioxidant, 20-55 parts of white filler, and the balance being ethylene-vinyl acetate resin.
[0008] As a further embodiment of the present invention, the crosslinking agent is one or more of 2-ethylhexyl carbonate tert-butyl peroxide, dicumyl peroxide, 2,5-di-tert-butylperoxide-2,5-dimethylhexane, tert-butyl peroxide isopropylbenzene, and butyl-4,4-bis(tert-butylperoxy)valerate; the coupling agent is one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(b-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltriisopropoxysilane.
[0009] As a further embodiment of the present invention, the light stabilizer is one or more of the following: hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, and bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate; the antioxidant is one or more of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, 4,4'-thiobis(3-methyl-6-tert-butylphenol), and tris(2,4-di-tert-butylphenyl) phosphite.
[0010] As a further embodiment of the present invention, the reflective filler is one or more of titanium dioxide, calcium titanate, calcium carbonate, and barium sulfate.
[0011] As a further embodiment of the present invention, the basis weight of both the low-flow support layer and the white adhesive layer is 50-150 g / m².
[0012] As a further embodiment of the present invention, the melt index of the base resin of the low-flow support layer is 5-15 g / 10 min, and the melt index of the base resin of the white adhesive layer is 15-20 g / 10 min.
[0013] As a further aspect of the present invention, the pre-crosslinking degree of the white EVA film is 30-45 parts.
[0014] A method for preparing a high-reflectivity white EVA film includes the following specific steps: Step 1: The light stabilizer, antioxidant, titanium dioxide, and EVA were mixed in a designed ratio, melt-extruded, and then cut and granulated to obtain the first functional masterbatch. The light stabilizer, antioxidant, titanium dioxide, glass fiber and EVA are mixed in the design ratio, melt extruded and then cut and granulated to obtain the second functional masterbatch. Step Two: A designed ratio of crosslinking agent and coupling agent is added to the first functional masterbatch and mixed to obtain a first mixture. A crosslinking agent and a coupling agent in a designed ratio are added to the second functional masterbatch and mixed to obtain a second mixture. Step 3: Using a three-layer co-extrusion extrusion device, the first mixture and the second mixture are poured into a feeding cylinder and melt-extruded to obtain a white EVA film with a three-layer co-extrusion structure. Step Four: After extrusion into a film, a slitting machine is used to cut the film into the required width to obtain a high-reflectivity white EVA film.
[0015] Because the present invention adopts the above technical solution, the advantages and positive effects of the present invention are as follows: 1. Compared with traditional white glazed glass and white film, it has a higher reflectivity, with a reflectivity of over 92 in the 400-110nm band; 2. Compared with traditional aluminized film, the appearance is more in line with the client's aesthetics, and it has excellent insulation performance. The diffuse reflection design makes the power generation gain more stable.
[0016] 3. Compared to mainstream screen protectors, the manufacturing process is simpler and the production cost is lower. Attached Figure Description
[0017] Figure 1 This is a cross-sectional schematic diagram of a high-reflectivity white EVA film according to the present invention. In the diagram: 1 is the low-flow support layer, and 2 is the white adhesive layer. Detailed Implementation
[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0019] like Figure 1 As shown, a high-reflectivity white EVA film of the present invention includes a low-flow support layer 1, and white adhesive layers 2 are respectively connected to both sides of the low-flow support layer 1. The white EVA film is applied between the cells of a photovoltaic module, around the edges of the photovoltaic module, and on the back glass of the photovoltaic module. The low-flow support layer 1, calculated in 100 parts by weight, contains 0.1-1 parts of crosslinking agent, 0.2-1 parts of silane coupling agent, 0.01-0.2 parts of light stabilizer, 0.01-0.2 parts of antioxidant, 25-50 parts of white filler, 5-15 parts of glass fiber, and the balance is ethylene-vinyl acetate resin. The white adhesive layer 2, calculated in 100 parts by weight, contains 0.1-1 parts of crosslinking agent, 0.2-1 parts of silane coupling agent, 0.01-0.2 parts of light stabilizer, 0.01-0.2 parts of antioxidant, 20-55 parts of white filler, and the balance is ethylene-vinyl acetate resin.
[0020] Example 1 The first functional masterbatch is prepared by mixing 69.8 parts by weight of EVA resin, 30 parts by weight of titanium dioxide, 0.1 parts by weight of antioxidant and 0.1 parts by weight of light stabilizer in a stirring tank, melting and extruding, cooling and cutting granulation. 59.8 parts by weight of EVA resin, 30 parts by weight of titanium dioxide, 0.1 parts by weight of antioxidant, 0.1 parts by weight of light stabilizer, and 10 parts by weight of glass fiber (powder) were mixed and stirred in a stirring tank. After melt extrusion, cooling, cutting, and granulation, a second functional masterbatch was obtained. Add 0.35 parts of crosslinking agent and 0.15 parts of coupling agent to 99.5 parts by weight of functional masterbatch 1, and mix and stir to obtain the first mixed material. Add 0.25 parts of crosslinking agent and 0.20 parts of coupling agent to 99.55 parts by weight of functional masterbatch 2, and mix and stir to obtain a second mixed material; Using a three-layer co-extrusion extruder, the first and second mixed materials are poured into a feeding cylinder and melt-extruded to obtain a three-layer white EVA film.
[0021] After extrusion into a film, the film is cut into 5mm widths using a slitting machine to obtain a high-reflectivity white EVA film.
[0022] Example 2 The first functional masterbatch was prepared by mixing 72.65 parts by weight of EVA resin, 27 parts by weight of titanium dioxide, 0.2 parts by weight of antioxidant and 0.15 parts by weight of light stabilizer in a stirring tank, melting and extruding, cooling and cutting granulation. 61.65 parts by weight of EVA resin, 30 parts by weight of titanium dioxide, 0.2 parts by weight of antioxidant, 0.15 parts by weight of light stabilizer, and 8 parts by weight of glass fiber (powder) were mixed and stirred in a stirring tank. After melt extrusion, cooling, cutting, and granulation, a second functional masterbatch was obtained. Add 0.25 parts of crosslinking agent and 0.25 parts of coupling agent to 99.5 parts by weight of functional masterbatch 1, and mix and stir to obtain the first mixed material. Add 0.3 parts of crosslinking agent and 0.25 parts of coupling agent to 99.45 parts by weight of functional mother 2, and mix and stir to obtain a second mixed material; Using a three-layer co-extrusion extruder, the first and second mixed materials are poured into a feeding cylinder and melt-extruded to obtain a three-layer white EVA film.
[0023] After extrusion into a film, the film is cut into 5mm widths using a slitting machine to obtain a high-reflectivity white EVA film.
[0024] Example 3 The first functional masterbatch is prepared by mixing 65.75 parts by weight of EVA resin, 34 parts by weight of titanium dioxide, 0.12 parts by weight of antioxidant and 0.14 parts by weight of light stabilizer in a stirring tank, melting and extruding, cooling and cutting granulation. 64.65 parts by weight of EVA resin, 26 parts by weight of titanium dioxide, 0.18 parts by weight of antioxidant, 0.17 parts by weight of light stabilizer, and 9 parts by weight of glass fiber (powder) were mixed and stirred in a stirring tank. After melt extrusion, cooling, cutting, and granulation, a second functional masterbatch was obtained. Add 0.35 parts of crosslinking agent and 0.27 parts of coupling agent to 99.38 parts by weight of functional masterbatch 1, and mix and stir to obtain the first mixed material. Add 0.32 parts of crosslinking agent and 0.27 parts of coupling agent to 99.41 parts by weight of functional mother 2, and mix and stir to obtain a second mixed material; Using a three-layer co-extrusion extruder, the first and second mixed materials are poured into a feeding cylinder and melt-extruded to obtain a three-layer white EVA film.
[0025] After extrusion into a film, the film is cut into 5mm widths using a slitting machine to obtain a high-reflectivity white EVA film.
[0026] As shown in Table 1, compared with traditional white glazed glass and white film, it has a higher reflectivity, with a reflectivity of over 92% in the 400-110nm band; compared with traditional aluminum-coated film, its appearance is more in line with the client's aesthetics, and it has excellent insulation performance. The diffuse reflection design makes the power generation gain more stable.
[0027] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.
Claims
1. A high-reflectivity white EVA film, characterized in that: It includes a low-flow support layer (1), with white adhesive layers (2) connected to both sides of the low-flow support layer (1). The white EVA film is applied between the cells of the photovoltaic module, around the edges of the photovoltaic module, and on the back glass of the photovoltaic module.
2. The high-reflectivity white EVA film according to claim 1, characterized in that: The low-flow support layer (1) is calculated in 100 parts by weight as follows: 0.1-1 parts crosslinking agent, 0.2-1 parts silane coupling agent, 0.01-0.2 parts light stabilizer, 0.01-0.2 parts antioxidant, 25-50 parts white filler, 5-15 parts glass fiber, and the balance is ethylene-vinyl acetate resin.
3. The high-reflectivity white EVA film according to claim 1, characterized in that: The white adhesive layer (2) is calculated in 100 parts by weight as follows: 0.1-1 parts crosslinking agent, 0.2-1 parts silane coupling agent, 0.01-0.2 parts light stabilizer, 0.01-0.2 parts antioxidant, 20-55 parts white filler, and the balance is ethylene-vinyl acetate resin.
4. A high-reflectivity white EVA film according to claim 2 or 3, characterized in that: The crosslinking agent is one or more of 2-ethylhexyl carbonate tert-butyl peroxide, dicumyl peroxide, 2,5-di-tert-butylperoxide-2,5-dimethylhexane, tert-butyl peroxide isopropylbenzene, and butyl-4,4-bis(tert-butylperoxy)valerate; the coupling agent is one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(b-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltriisopropoxysilane.
5. A high-reflectivity white EVA film according to claim 2 or 3, characterized in that: The light stabilizer is one or more of the following: hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, and bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate; the antioxidant is one or more of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, 4,4'-thiobis(3-methyl-6-tert-butylphenol), and tris(2,4-di-tert-butylphenyl) phosphite.
6. A high-reflectivity white EVA film according to claim 2 or 3, characterized in that: The reflective filler is one or more of titanium dioxide, calcium titanate, calcium carbonate, and barium sulfate.
7. The high-reflectivity white EVA film according to claim 1, characterized in that: The low-flow support layer (1) and the white adhesive layer (2) both have a basis weight of 50-150 g / m².
8. The high-reflectivity white EVA film according to claim 1, characterized in that: The base resin melt index of the low flow support layer (1) is 5-15 g / 10 min, and the base resin melt index of the white adhesive layer (2) is 15-20 g / 10 min.
9. The high-reflectivity white EVA film according to claim 1, characterized in that: The pre-crosslinking degree of the white EVA film is 30-45 parts.
10. A method for preparing a high-reflectivity white EVA film according to any one of claims 1-9, characterized in that: Including the following Specific steps: Step 1: The light stabilizer, antioxidant, titanium dioxide, and EVA were mixed in a designed ratio, melt-extruded, and then cut and granulated to obtain the first functional masterbatch. The light stabilizer, antioxidant, titanium dioxide, glass fiber and EVA are mixed in the design ratio, melt extruded and then cut and granulated to obtain the second functional masterbatch. Step Two: A designed ratio of crosslinking agent and coupling agent is added to the first functional masterbatch and mixed to obtain a first mixture. A crosslinking agent and a coupling agent in a designed ratio are added to the second functional masterbatch and mixed to obtain a second mixture. Step 3: Using a three-layer co-extrusion extrusion device, the first mixture and the second mixture are poured into a feeding cylinder and melt-extruded to obtain a white EVA film with a three-layer co-extrusion structure. Step Four: After extrusion into a film, the film is cut using a slitting machine to obtain a high-reflectivity white EVA film.