Polyester base film for solar back sheet and solar back sheet
Technical Field
The invention relates to the technical field of solar back panels, in particular to a polyester base film for a solar back panel and a solar back panel with the polyester base film.
Background
The polyester film has excellent electrical insulation, thermal property and mechanical property, and can be widely applied to a plurality of fields such as solar batteries, electronics and electrics and the like. Because the content of polyester in the polyester film is more than 70 percent, the adhesive force between the polyester film and an ethylene/vinyl acetate copolymer (EVA) packaging adhesive film is poor, and the polyester film can only be used as a middle support layer in a solar backboard.
At present, although the technology of blending and modifying polyethylene terephthalate (PET) by Polyolefin (PE) exists, the technology still has the defects. For example, in patent CN109485965A, 30% or less of reinforced resin (polyester) and polyolefin are blended to form a core layer, and a large amount of polyolefin is used as a main resin for an easy adhesion layer, which is well adhered to EVA, but a co-extruded film is also used as a support layer of a back panel, and the mechanical strength of the prepared film is below 50MPa, which cannot meet the requirements of the current national and industrial standards of solar back panels; the polyester formula of the prior back plate technology and the polyester and polyolefin blending modification formula in the patent adopt two-layer co-extrusion, and are also used as a support layer and an adhesive layer of the back plate, because the polyester content in the prior back plate technology is more than 80%, the polyester and polyolefin blending formula in the patent has the polyester content of less than 30%, the polarity difference of the two layers is obvious, and phase separation exists between the two layers, the interlayer difference of the two layers is poor, when the adhesive layer is laminated and bonded with an EVA packaging adhesive film, interlayer delamination can occur between the intermediate layer and the adhesive layer, and interlayer delamination after humid heat aging is more serious, so the intermediate layer and the adhesive layer still need an adhesive for bonding and compounding. More than 75% of polyester resin is added in patent CN109608837A, the mechanical strength of the film can meet the requirement, but the film is directly used as the bonding layer of the back plate and has poor bonding performance with EVA.
In view of the foregoing, there is still a need for an improved polyester film.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, an object of the present invention is to propose a polyester-based film for solar back sheets and a solar back sheet. The polyester base film and the solar cell packaging adhesive film have excellent binding power and excellent mechanical property, can be used as a binding layer and a supporting body layer of a solar backboard, and have wide application prospect.
In one aspect of the present invention, a polyester-based film for a solar back sheet is provided. According to an embodiment of the present invention, the polyester based film for a solar back sheet includes a bonding layer and a base layer, the bonding layer including: 10-35 parts by weight of a polyester; 5-20 parts by weight of a compatibilizer; 50-74 parts by weight of a polyolefin; and 5 to 9.5 parts by weight of an inorganic filler.
According to the polyester base film for the solar backboard, the adhesive layer is formed by modifying polyester through polyolefin, so that the adhesive force between the polyester base film and solar cell packaging film adhesive (such as EVA packaging film adhesive) can be remarkably improved, the polyester base film can be effectively prevented from being oxidized, and the service life of a cell module is prolonged. Meanwhile, the compatilizer is adopted, so that the compatibility of polyolefin and polyester materials can be obviously improved, and the interlayer force between the bonding layer and the substrate layer can be improved. Therefore, the polyester base film for the solar backboard provided by the invention has excellent adhesive force and excellent mechanical property, can be used as an adhesive layer and a support layer of the solar backboard, and has wide application prospect.
In addition, the polyester-based film for solar back sheets according to the above embodiments of the present invention may further have the following additional technical features:
in some embodiments of the invention, the substrate layer comprises: 78-90 parts by weight of a polyester; 3-5 parts by weight of a compatibilizer; and 5 to 15 parts by weight of an inorganic filler.
In some embodiments of the invention, the polyester is selected from at least one of polyethylene terephthalate, 1, 4-cyclohexanedimethanol polyester, polybutylene terephthalate, polyethylene 2, 6-naphthalate, and polypropylene terephthalate.
In some embodiments of the invention, the compatibilizer is an ethylene copolymer (a copolymer having a similar structure to ethylene), such as ethylene-methacrylate copolymer-g-maleic anhydride, ethylene-acrylate copolymer-g-maleic anhydride, polyethylene-g-maleic anhydride, ethylene-propylene copolymer-g-maleic anhydride, polyethylene-g-glycidyl methacrylate, ethylene-ethyl acetate copolymer-g-maleic anhydride, ethylene-propylene copolymer-g-glycidyl methacrylate, ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, ethylene-methacrylate copolymer-g-glycidyl methacrylate, ethylene-methyl acrylate copolymer-g-methyl acrylate copolymer, ethylene-methyl, Ethylene-acrylate copolymer-g-at least one of glycidyl methacrylate, ethylene/ethyl acrylate/glycidyl methacrylate copolymer, and ethylene/glycidyl methacrylate copolymer.
In some embodiments of the invention, the polyolefin is selected from at least one of polyethylene and ethylene-propylene copolymers.
In some embodiments of the present invention, the inorganic filler is selected from at least one of titanium dioxide, barium sulfate, zinc oxide, zirconium oxide, aluminum oxide, and calcium carbonate.
In some embodiments of the present invention, the thickness of the bonding layer is 10 to 35 μm.
In some embodiments of the present invention, the thickness of the base layer is 150 to 350 μm.
In some embodiments of the present invention, the adhesive layer further comprises 0.5 to 1 part by weight of an auxiliary.
In some embodiments of the present invention, the substrate layer further comprises 0.5 to 2 parts by weight of an auxiliary agent.
In some embodiments of the present invention, the adjuvant is selected from at least one of an anti-hydrolysis agent, an ultraviolet absorber, an antioxidant, and a flame retardant.
In another aspect of the present invention, a solar back sheet is provided. According to an embodiment of the present invention, the solar back sheet includes the polyester-based film for a solar back sheet of the above embodiment. The polyester base film for a solar back sheet of the above examples can be used as both a support layer and an adhesive layer of a solar back sheet due to its excellent adhesive force and mechanical properties. Therefore, the solar backboard is simple in processing technology and excellent in adhesive force and mechanical property.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Detailed Description
The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
In one aspect of the present invention, a polyester-based film for a solar back sheet is provided. According to an embodiment of the present invention, the polyester based film for a solar back sheet includes a bonding layer and a base layer, the bonding layer including: 10-35 parts by weight of a polyester; 5-20 parts by weight of a compatibilizer; 50-74 parts by weight of a polyolefin; and 5 to 9.5 parts by weight of an inorganic filler.
The inventor finds that the adhesive force between the polyester base film and the EVA packaging film adhesive and the mechanical property of the polyester base film can be remarkably improved by controlling the content of each component in the polyester base film adhesive layer for the solar back panel in the range. In the adhesive layer, if the content of polyester is too high, the adhesive force between the polyester-based film and EVA is deteriorated; if the content of polyester is too low, the mechanical properties of the polyester-based film adhesive layer and the interlayer force between the adhesive layer and the substrate layer are reduced. If the content of the compatibilizer is too high, the mechanical properties of the polyester-based film are lowered; if the content of the compatibilizer is too low, the compatibility of the polyester with the polyolefin is deteriorated, the interlayer strength between the adhesive layer and the base layer is reduced, and if the content of the compatibilizer is too high, the mechanical properties of the polyester-based film are reduced, and the cost is increased. If the content of the polyolefin is too high, the interlayer force between the bonding layer and the substrate layer is reduced; if the content of the polyolefin is too low, the adhesion between the polyester-based film and EVA may be deteriorated, and the water blocking property may be deteriorated. In addition, the bonding layer adopts the inorganic filler with the content, so that the inorganic filler and other components can be fully and uniformly mixed to form a uniform system, and the performance of each component in the polyester base film is further exerted.
The polyester base film for a solar back sheet according to an embodiment of the present invention is further described in detail below.
According to an embodiment of the invention, the substrate layer comprises: 78-90 parts by weight of a polyester; 3-5 parts by weight of a compatibilizer; and 5 to 15 parts by weight of an inorganic filler. The inventors have found that by controlling the content of each component in the polyester-based film base layer for a solar back sheet to be in the above range, the mechanical properties of the base layer and the compatibility of the base layer with the adhesive layer can be significantly improved. In the base layer, if the content of the polyester is too high, the interlayer force between the base layer and the adhesive layer is reduced; if the content of the polyester is too low, the mechanical properties of the polyester-based film may be degraded. If the content of the compatibilizer is too high, the mechanical properties of the polyester-based film are lowered; if the content of the compatibilizer is too low, the interlayer force between the substrate layer and the adhesive layer is reduced. In addition, the base layer adopts the inorganic filler with the content, so that the inorganic filler and other components can be fully and uniformly mixed to form a uniform system, and the performance of each component in the polyester base film can be further exerted.
According to an embodiment of the present invention, the polyester may be at least one selected from the group consisting of polyethylene terephthalate, 1, 4-cyclohexanedimethanol polyester, polybutylene terephthalate, polyethylene 2, 6-naphthalate, and polytrimethylene terephthalate, preferably polyethylene terephthalate (PET). The polyester can provide excellent mechanical properties to the polyester-based film and has good compatibility with other components in the polyester-based film. By adopting the polyester, the mechanical property of the polyester base film and the interlayer force between the base layer and the bonding layer in the polyester base film can be further improved.
According to an embodiment of the present invention, the compatibilizer is selected from copolymers having a structure similar to that of ethylene, and may be, for example, ethylene-methacrylate copolymer-g-maleic anhydride, ethylene-acrylate copolymer-g-maleic anhydride, polyethylene-g-maleic anhydride, ethylene-propylene copolymer-g-maleic anhydride, polyethylene-g-glycidyl methacrylate, ethylene-ethyl acetate copolymer-g-maleic anhydride, ethylene-propylene copolymer-g-glycidyl methacrylate, ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, ethylene-methacrylate copolymer-g-glycidyl methacrylate, ethylene-ethyl acetate copolymer-g-maleic anhydride, ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, ethylene-ethyl acrylate copolymer-g-glycidyl methacrylate, ethylene-, Ethylene-acrylate copolymer-g-at least one of glycidyl methacrylate, ethylene/ethyl acrylate/glycidyl methacrylate copolymer, and ethylene/glycidyl methacrylate copolymer. By adopting the compatilizer, the interlayer between the substrate layer and the bonding layer in the polyester base film can be further improved, and the compatibility between the polyester and the polyolefin in the bonding layer and the mechanical property of the polyester base film can be further improved.
According to an embodiment of the present invention, the polyolefin may be at least one selected from the group consisting of polyethylene and ethylene-propylene copolymer. Therefore, the adhesive force between the polyester base film and the EVA can be further improved, and the polyester base film is ensured to have excellent adhesive force and mechanical property so as to meet the requirements of being used as a support layer and an adhesive layer of the solar back panel.
According to an embodiment of the present invention, the inorganic filler may be at least one selected from the group consisting of titanium dioxide, barium sulfate, zinc oxide, zirconium oxide, aluminum oxide, and calcium carbonate, preferably titanium dioxide, and more preferably rutile type titanium dioxide. The inorganic filler can be fully and uniformly mixed with other components in the polyester base film to form a uniform system, thereby further facilitating the performance exertion of the performances of all the components in the polyester base film
According to an embodiment of the present invention, the thickness of the adhesive layer may be 10 to 35 μm, for example, 10 μm, 12 μm, 15 μm, 20 μm, 23 μm, 25 μm, 30 μm, 32 μm, or 35 μm. This can further contribute to the exertion of the adhesive layer performance.
According to an embodiment of the present invention, the thickness of the substrate layer may be 150 to 350 μm, such as 150 μm, 200 μm, 250 μm, 300 μm or 350 μm. This can further contribute to the performance of the base layer.
According to an embodiment of the invention, the bonding layer further comprises 0.5-1 part by weight of an auxiliary agent. This can further improve the weather resistance of the polyester base film in use.
According to an embodiment of the present invention, the substrate layer further comprises 0.5 to 2 parts by weight of an auxiliary agent. This can further improve the weather resistance of the polyester base film in use.
According to an embodiment of the present invention, the auxiliary may be at least one selected from the group consisting of an anti-hydrolysis agent, an ultraviolet absorber (also referred to as an ultraviolet resistant auxiliary), an antioxidant, and a flame retardant. It is to be noted that specific kinds of the above-mentioned hydrolysis-resistant agent, ultraviolet absorber, antioxidant and flame retardant are not particularly limited, and commercially available conventional products can be used.
As described above, the polyester-based film for solar back sheets according to embodiments of the present invention may have at least one selected from the following advantages:
1. the polyester base film has the advantages that the adhesive layer is formed by modifying polyester through polyolefin, the polyolefin accounts for more than 50% of the mass percentage of the adhesive layer, the good adhesive force between the polyester base film and the packaging adhesive film is guaranteed, the battery piece can be prevented from being oxidized, and the service life of the battery pack is prolonged.
2. The compatilizer is added into the bonding layer of the polyester base film, the content of the compatilizer is more than 5%, the compatibility of polyolefin and polyester is ensured, and the interlayer force between the bonding layer and the base layer is increased.
3. The compatilizer is added into the matrix layer of the polyester-based film, the content of the compatilizer is more than 3%, and good compatibility of the matrix layer and the bonding layer interface is ensured.
4. The polyester content in the matrix layer of the polyester-based film is more than 78%, so that the mechanical property of the polyester-based film is ensured.
5. The polyester base film is simple to prepare and process, can be widely applied to processing production of the solar backboard, and simplifies the processing and forming process of the solar backboard by applying the base film.
In another aspect of the present invention, a solar back sheet is provided. According to an embodiment of the present invention, the solar back sheet includes the polyester-based film for a solar back sheet of the above embodiment. The polyester base film for a solar back sheet of the above examples can be used as both a support layer and an adhesive layer of a solar back sheet due to its excellent adhesive force and mechanical properties. Therefore, the solar backboard is simple in processing technology and excellent in adhesive force and mechanical property.
In addition, it should be noted that the solar back sheet has all the features and advantages described above for the "polyester-based film for solar back sheet", and thus detailed description thereof is omitted here.
The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way. In addition, unless otherwise specified, the adhesive layer and the base layer of the polyester-based film in the following examples and comparative examples were obtained by twin-screw extrusion of a polyester or the like component in a compounding ratio with an auxiliary and an inorganic filler.
Example 1
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 10 parts of polyethylene terephthalate, 5 parts of ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, 75 parts of polyethylene, 9.5 parts of titanium dioxide, 0.2 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent, 0.1 part of antioxidant and 10 mu m of thickness of the bonding layer.
The polyester-based film matrix layer comprises the following components in parts by weight: 78 parts of polyethylene terephthalate, 5 parts of polyethylene-g-glycidyl methacrylate, 15 parts of titanium dioxide, 0.5 part of ultraviolet absorbent, 1.2 parts of hydrolysis resistant agent, 0.3 part of antioxidant and 250 mu m of thickness of a substrate layer.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And compounding a polyvinylidene fluoride (PVDF) film with a matrix layer of a polyester base film through an adhesive, and curing to obtain the solar backboard.
Example 2
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 16 parts of polyethylene terephthalate, 9 parts of ethylene-methacrylate copolymer-g-glycidyl methacrylate, 65 parts of polyethylene, 8 parts of titanium dioxide, 0.8 part of ultraviolet absorbent, 0.5 part of flame retardant, 0.2 part of hydrolysis resistant agent, 0.5 part of antioxidant and 23 mu m of thickness of the bonding layer.
The polyester-based film matrix layer comprises the following components in parts by weight: 84 parts of polyethylene terephthalate, 3 parts of ethylene/ethyl acrylate/glycidyl methacrylate copolymer, 12.5 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 200 mu m of thickness of the substrate layer.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And compounding the Tedeler fluorine film with a substrate layer of the polyester base film through an adhesive, and curing to obtain the solar backboard.
Example 3
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 23 parts of polyethylene terephthalate, 20 parts of ethylene-acrylate copolymer-g-glycidyl methacrylate, 50 parts of ethylene-propylene copolymer, 7.5 parts of titanium dioxide, 0.2 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 0.1 part of antioxidant; the thickness of the adhesive layer was 35 μm.
The polyester-based film matrix layer comprises the following components in parts by weight: 87 parts of polyethylene terephthalate, 4 parts of ethylene-acrylate copolymer-g-glycidyl methacrylate, 7.5 parts of titanium dioxide, 0.8 part of ultraviolet absorbent, 0.7 part of hydrolysis resistant agent and 300 mu m of thickness of a substrate layer.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And coating the fluorocarbon coating on the substrate layer of the polyester base film, and drying and curing to obtain the solar backboard.
Example 4
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 28 parts of polyethylene terephthalate, 16 parts of polyethylene-g-maleic anhydride, 50 parts of polyethylene, 5 parts of titanium dioxide, 0.2 part of ultraviolet absorbent, 0.2 part of flame retardant, 0.3 part of hydrolysis resistant agent and 0.3 part of antioxidant; the thickness of the adhesive layer was 30 μm.
The polyester-based film matrix layer comprises the following components in parts by weight: 84 parts of polyethylene terephthalate, 3 parts of polyethylene-g-maleic anhydride, 12.5 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 350 mu m of thickness of the substrate layer.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And coating the fluorocarbon coating on the substrate layer of the polyester base film, drying and curing to obtain the solar backboard.
Example 5
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 35 parts of polyethylene terephthalate, 8 parts of ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, 50 parts of polyethylene, 6.4 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 0.1 part of antioxidant; the thickness of the adhesive layer was 15 μm.
The polyester-based film matrix layer comprises the following components in parts by weight: 90 parts of polyethylene glycol terephthalate, 4.5 parts of ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, 5 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 150 mu m of thickness of a substrate layer.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And compounding the Tedeler fluorine film with a substrate layer of the polyester base film through an adhesive, and curing to obtain the solar backboard.
Comparative example 1
The polyester-based film comprises the following components in parts by weight: 90 parts of polyethylene terephthalate, 9.5 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 150 mu m of film thickness.
Preparing a solar back panel: and compounding the Tedeler fluorine film with the polyester base film through an adhesive, and curing to obtain the solar backboard.
Comparative example 2
The polyester base film comprises no matrix layer and only a bonding layer, wherein the bonding layer comprises the following components in parts by weight: 25 parts of polyethylene terephthalate, 5 parts of ethylene-ethyl acetate copolymer-g-glycidyl methacrylate, 63 parts of polyethylene, 6.4 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 0.1 part of antioxidant; the thickness of the polyester-based film was 250. mu.m.
Preparing a solar back panel: and coating the fluorocarbon coating on the outer layer of the PET, and curing to obtain the solar backboard.
Comparative example 3
(1) Preparation of polyester base film for solar back panel
The polyester-based film bonding layer comprises the following components in parts by weight: 18 parts of polyethylene terephthalate, 5 parts of polyethylene-g-maleic anhydride, 70 parts of polyethylene, 6.4 parts of titanium dioxide, 0.3 part of ultraviolet absorbent, 0.2 part of hydrolysis resistant agent and 0.1 part of antioxidant; the thickness of the adhesive layer was 25 μm.
The polyester-based film matrix layer comprises the following components in parts by weight: 90 parts of polyethylene terephthalate, 9.5 parts of titanium dioxide, 0.3 part of ultraviolet absorbent and 0.2 part of hydrolysis resistant agent; the thickness of the matrix layer was 150 μm.
And co-extruding and stretching the two layers of materials to obtain the polyester base film for the solar backboard.
(2) Preparation of solar back sheet
And coating the fluorocarbon coating on the outer layer of the PET, and curing to obtain the solar backboard.
Test method
The polyester-based film materials prepared in the examples 1 to 5 and the comparative examples 1 to 3 are prepared and tested according to GB/T31034-2014 (insulating back plate for crystalline silicon solar cell module) and CQC3308-2013 (back plate technical specification for photovoltaic module packaging). The adhesion between the prepared solar back plate and EVA is tested by adopting the adhesion after initial and double 95-degree humid heat aging (95 ℃ and 95% humidity) for ten days. The results are shown in table 1:
TABLE 1 examination results of examples of the present invention and comparative examples
The test result shows that the polyester-based film provided by the invention has excellent bonding force and excellent mechanical property compared with the EVA packaging film adhesive commonly used in the field at present. The polyester-based film of comparative example 1 does not contain polyolefin, and its adhesion to EVA is significantly reduced. The polyester-based film of comparative example 2 does not contain a matrix layer and its mechanical properties are significantly reduced. The polyester-based film substrate layer of comparative example 3 had too high a polyester content and no compatibilizer, and therefore had low cohesion with the polyester-based film substrate layer and the adhesive layer, so that the performance of the adhesive layer was difficult to exert and it was not effective in adhesion with EVA.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.