Encapsulant composition, encapsulant, and photovoltaic module

Abstract

The application provides a kind of adhesive film composition, encapsulation adhesive film and photovoltaic module. The adhesive film composition includes 100 parts of base resin, 1-10 parts of crosslinking agent and 0.01-5 parts of catalyst by weight fraction; wherein, the crosslinking agent is binary ester compound and / or polybasic ester compound, the catalyst is ester exchange reaction catalyst, and the base resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer. Under certain stimulation (generally heating), the encapsulation adhesive film can be melted, which easily separates the parts of the photovoltaic module. Not only the encapsulation adhesive film can be recycled, but also the other parts of the photovoltaic module can be recycled without damage, improving the recycling efficiency. In addition, even if the encapsulation adhesive film has problems such as bubbles after lamination, it can be re-laminated through the principle of reversible crosslinking, thereby improving the yield of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectricity, in particular to a film composition, a packaging film and a photovoltaic module. BACKGROUND

[0002] Solar energy is a very environmentally friendly renewable energy, and converting it into electrical energy through solar cells helps to solve the global energy crisis and environmental pollution problems. Photovoltaic film is an indispensable part of silicon solar cell panels, and the raw materials of existing commercial photovoltaic films are mainly EVA and POE, which are linear polymers. Their softening points are relatively low, and they will creep at the working temperature of the battery. Therefore, a crosslinking agent is usually added to the film raw material, and the raw material can be crosslinked to form a three-dimensional network structure when laminated at high temperature, meeting the use requirements of solar modules under various conditions. However, the crosslinking currently used is permanent crosslinking, and the crosslinked film is insoluble and infusible. If there are problems such as bubbles in the lamination, the module can only be discarded. If the glass, battery sheet, back sheet and other parts of the solar cell panel are separated and recycled after reaching the service life, extensive recycling methods such as calcination, acid and alkali soaking are often used. These methods ultimately need to go through complex steps to separate and purify materials such as crystalline silicon, resulting in high energy consumption and waste, which is not conducive to sustainable development. SUMMARY

[0003] The main purpose of the present application is to provide a film composition, a packaging film and a photovoltaic module to solve the problems of low recycling rate, high recycling cost and low yield of laminated products of the traditional film in the prior art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a film composition is provided, which comprises, in parts by weight, 100 parts of a base resin; 1-10 parts of a crosslinking agent and 0.01-5 parts of a catalyst; wherein the crosslinking agent is a diester compound and / or a polybasic ester compound, the catalyst is an ester exchange reaction catalyst, and the base resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer.

[0005] Further, the boiling point of the crosslinking agent is greater than 150°C, preferably the diester compound and / or the polybasic ester compound is obtained by esterification reaction of a carboxylic acid compound and an alcohol compound, when the base resin is the ethylene-vinyl acetate copolymer, the crosslinking agent is preferably crosslinking agent A, the crosslinking agent A is a diester compound and / or a polybasic ester compound formed by a di-carboxylic acid compound and / or a poly-carboxylic acid compound and an alcohol compound; preferably the di-carboxylic acid compound is selected from C2-C12 aliphatic di-carboxylic acid and / or C6-C12 aromatic di-carboxylic acid, and the alcohol compound is selected from C1-C12 aliphatic alcohol and / or C6-C12 aromatic alcohol. 15any one or more of C1-C20 aliphatic monoalcohols, benzyl alcohol, phenethyl alcohol; further, preferably the VA content in the ethylene-vinyl acetate copolymer is 20-60%. 15 any one or more of C1-C20 aliphatic monoalcohols, benzyl alcohol, phenethyl alcohol; further, preferably the VA content in the ethylene-vinyl acetate copolymer is 20-60%.

[0006] Further, when the above-mentioned base resin is selected from any one or more of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer, preferably the crosslinking agent is crosslinking agent B, the crosslinking agent B is a diester compound formed from a dihydric alcohol compound and / or a polyhydric alcohol compound and a carboxylic acid compound and / or the polyester compound; preferably the dihydric alcohol compound is selected from any one or more of C2-C20 aliphatic dihydric alcohols, p-(m-)xylyl dihydric alcohols, preferably the polyhydric alcohol compound is selected from any one or more of glycerol, polyether polyhydric alcohols, and preferably the carboxylic acid compound is selected from any one or more of C1-C20 aliphatic mono-carboxylic acids, benzoic acid, phenylacetic acid. 15 any one or more of C1-C20 aliphatic monoalcohols, benzyl alcohol, phenethyl alcohol; further, preferably the VA content in the ethylene-vinyl acetate copolymer is 20-60%. 15 any one or more of C1-C20 aliphatic monoalcohols, benzyl alcohol, phenethyl alcohol; further, preferably the VA content in the ethylene-vinyl acetate copolymer is 20-60%.

[0007] Further, when the above-mentioned base resin is a mixture of any one or more of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer and ethylene-vinyl acetate copolymer, preferably the crosslinking agent is crosslinking agent A and / or crosslinking agent B.

[0008] Further, the above-mentioned catalyst is selected from any one or more of zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, benzene sulfonic acid, stannous octoate.

[0009] Further, the adhesive film composition further comprises 0.1-0.4 parts of an ultraviolet absorber, preferably the ultraviolet absorber is selected from any one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone; preferably the adhesive film composition further comprises 0.1-5 parts of an adhesion promoter, preferably the adhesion promoter is a silane coupling agent, preferably the silane coupling agent is selected from any one or more of methyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-triethoxysilylpropyl)disulfide, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0010] Further, the adhesive film composition further comprises 0.1-1.0 parts of a light stabilizer; preferably the light stabilizer is selected from any one or more of bis-2,2,6,6-tetramethylpiperidinooxy sebacate, 2,2,6,6-tetramethyl-4-piperidinostearate, tris-(2,2,6,6-tetramethylpiperidinooxy) phosphite, tris(1,2,2,6,6-pentamethylpiperidyl) phosphite, styrene-methylacrylic acid (2,2,6,6-tetramethylpiperidinyl) ester copolymer, poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine) succinate, polymer of t-octylamine triazine with ethylenediamine piperidine.

[0011] According to another aspect of the present application, there is provided an encapsulant adhesive film prepared from an adhesive film composition by a process comprising premixing, melt-extruding, casting into a film, cooling, slitting and winding, the adhesive film composition being as described above.

[0012] Further, the lamination is carried out at a temperature of 150-200°C, preferably for a time period of 10-60 minutes.

[0013] According to yet another aspect of the present application, there is provided a photovoltaic module comprising an encapsulant adhesive film, the encapsulant adhesive film being as described above.

[0014] By the technical solution of the present application, the base resin itself has a large number of carboxylic ester bonds and / or carboxyl groups, and the di(multi)carboxylic ester compound is added as a crosslinking agent, and under the action of a catalyst (ester exchange reaction catalyst), the crosslinking reaction of the base resin can be realized to form a reversible crosslinking network. If a certain external stimulus is given, the recombination of the crosslinking network can be realized, and the self-repairing performance is also achieved, and the base resin can also be recycled and reused. Specifically, under a certain stimulus (generally heating), the encapsulation adhesive film can be melted, and the photovoltaic module parts can be easily separated, and not only the encapsulation adhesive film can be recycled, but also the other parts of the photovoltaic module (such as the cell panel, glass, back panel, etc.) can be recycled without being damaged, and the recycling efficiency is improved. In addition, even if the encapsulation adhesive film has problems such as bubbles after lamination, it can also be laminated again through the principle of reversible crosslinking, thereby improving the yield of the product. DETAILED DESCRIPTION

[0015] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0016] As analyzed in the background, the recycling rate of the conventional adhesive film in the prior art is low, the recycling cost is high, and the yield of the product after lamination is low. In order to solve the problem, the present application provides an adhesive film composition, an encapsulation adhesive film and a photovoltaic module.

[0017] In a typical embodiment of the present application, an adhesive film composition is provided, which comprises, in parts by weight, 100 parts of a base resin; 1-10 parts of a crosslinking agent and 0.01-5 parts of a catalyst; wherein the crosslinking agent is a diester compound and / or a multiester compound, the catalyst is an ester exchange reaction catalyst, and the base resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer.

[0018] The dynamic reversible covalent bond is a covalent bond that can undergo "breakage-recombination" or exchange reaction under external stimulus (heat, light, acid, base, etc.); and when the stimulus is eliminated, it also shows the same high stability as ordinary covalent bond. The ester exchange reaction is a kind of dynamic reversible reaction, which refers to the reaction of ester with alcohol / acid / ester under the action of a catalyst to generate a new ester and a new alcohol / acid / ester.

[0019] The base resin itself contains a large number of carboxylic acid ester bonds and / or carboxyl groups. Adding di(poly)carboxylic acid ester compounds as crosslinking agents, under the action of a catalyst (ester exchange catalyst), allows the base resin to undergo a crosslinking reaction, forming a reversible crosslinked network. With certain external stimuli, this crosslinked network can be reorganized, exhibiting self-healing properties and enabling the recycling and reuse of the base resin. Specifically, under certain stimuli (generally heating), the encapsulating film can melt, easily separating the various parts of the photovoltaic module. Not only can the encapsulating film be recycled, but other parts of the photovoltaic module (such as the solar panel, glass, backsheet, etc.) can also be recycled without damage, improving recycling efficiency. Furthermore, even if problems such as bubbles arise after lamination, the encapsulating film can be re-laminated using the principle of reversible crosslinking, thereby improving product yield.

[0020] In one embodiment of this application, the boiling point of the crosslinking agent is greater than 150°C. Preferably, the diester compound and / or polyester compound is obtained by esterification reaction of carboxylic acid compound and alcohol compound. When the matrix resin is ethylene-vinyl acetate copolymer, the crosslinking agent is preferably crosslinking agent A, which is a diester compound and / or polyester compound formed by a diester compound and / or polyester compound and an alcohol compound. Preferably, the diester compound is selected from C2 to C4. 15 The compound is selected from any one or more of dialiphatic carboxylic acids, terephthalic acid, and terephthalic diacetic acid; preferably, the polycarboxylic acid compound is selected from any one or more of citric acid, isocitric acid, aconitic acid, homocitric acid, homoisocitric acid, homoaconitic acid, propane-1,2,3-tricarboxylic acid, trimesic acid, polyacrylic acid, and polymethacrylic acid; preferably, the alcohol compound is selected from C1 to C2. 15 It contains any one or more of aliphatic monohydric alcohols, benzyl alcohol, and phenethyl alcohol; further, it is preferred that the VA content in the ethylene-vinyl acetate copolymer is 20-60%.

[0021] The dynamic transesterification reaction between the matrix resin and the crosslinking agent ensures that after the encapsulating film has achieved its basic performance, subsequent recycling and reuse not only do not require destructive methods but also achieve high recycling efficiency. The boiling point of the crosslinking agent, within the aforementioned range, helps prevent volatilization during mixing, granulation, and lamination. When the matrix resin is an ethylene-vinyl acetate copolymer, since the side chains of the ethylene-vinyl acetate copolymer (before esterification) are alcoholic, the aforementioned carboxylic acid compounds and alcohol compounds are preferred, as they facilitate the transesterification reaction between the matrix and the crosslinking agent, thereby forming a network structure. Furthermore, since the crosslinking of the matrix resin is generated through VA groups, its content cannot be too low; the preferred VA content helps the matrix better form a crosslinked network structure.

[0022] In one embodiment of the present application, when the base resin is selected from any one or more of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer, the crosslinking agent is preferably crosslinking agent B, which is a di-ester compound and / or a poly-ester compound formed from a di-alcohol compound and / or a poly-alcohol compound and a carboxylic acid compound; preferably the di-alcohol compound is selected from any one or more of C2-C10di-aliphatic alcohol, p-(m)phenylenedimethanol, preferably the poly-alcohol compound is selected from any one or more of glycerol, polyether poly-alcohol, and further preferably the carboxylic acid compound is selected from any one or more of C1-C10aliphatic mono-carboxylic acid, benzoic acid, phenylacetic acid, and further, preferably the EA content in the ethylene-ethyl acrylate copolymer, the AA content in the ethylene-acrylic acid copolymer, and the MAA content in the ethylene-methacrylic acid copolymer are each independently 20-60%. 15 15

[0023] When the base resin is of the above kind, since the base resin is carboxylic acid structure before esterification or by itself, the above-mentioned alcohol compound is preferred, which helps the base resin and the crosslinking agent to undergo transesterification reaction to form a network structure.

[0024] To improve the efficiency and effect of the network structure formation by the transesterification reaction, when the base resin is selected from a mixture of any one or more of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer and ethylene-vinyl acetate copolymer, the crosslinking agent is preferably crosslinking agent A and / or crosslinking agent B.

[0025] Preferably, the above-mentioned catalyst is selected from any one or more of zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, benzenesulfonic acid, stannous octoate, which helps to improve the efficiency and effect of the dynamic transesterification reaction of the base resin.

[0026] ​​Preferably, the adhesive film composition further comprises 0.1 to 0.4 parts of a UV absorber, preferably the UV absorber is selected from any one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, thereby helping to improve the absorption of high-energy ultraviolet rays by the encapsulation adhesive film, and thereby facilitating effective mitigation of the aging of the adhesive film. Preferably, the adhesive film composition further comprises 0.1 to 5 parts of an adhesion promoter, preferably the adhesion promoter is a silane coupling agent, preferably the silane coupling agent is selected from any one or more of methyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-triethoxysilylpropyl)disulfide, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, thereby helping to improve the adhesion of the encapsulation adhesive film to glass, the encapsulation adhesive film to backsheet, and the like, and preventing delamination of the adhesive film.

[0027] Preferably, the adhesive film composition further comprises 0.1 to 1.0 parts of a light stabilizer, preferably the light stabilizer is selected from any one or more of bis-2,2,6,6-tetramethylpiperidinyl octodecanedioate, 2,2,6,6-tetramethyl-4-piperidinyl stearate, tris-(2,2,6,6-tetramethylpiperidinyl nitroxyl) phosphite, tris(1,2,2,6,6-pentamethylpiperidinyl) phosphite, styrene-methylacrylic acid (2,2,6,6-tetramethylpiperidinyl) ester copolymer, poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine) succinate, polymer of tertiary octylamine triazine and ethylenediamine piperidine, thereby helping to delay the aging process of the encapsulation adhesive film and improve the service life of the encapsulation adhesive film.

[0028] In another exemplary embodiment of the present application, there is provided an encapsulation adhesive film prepared from an adhesive film composition through a process of premixing, melt extrusion, film casting, cooling, slitting, and winding, and the adhesive film composition is the adhesive film composition described above.

[0029] The base resin in the encapsulation adhesive film prepared from the adhesive film composition inherently has a large number of acetate bonds and / or carboxyl groups, and the addition of a di(multi)carboxylic acid ester compound as a crosslinking agent can achieve crosslinking reaction of the base resin to form a reversible crosslinking network under the action of a catalyst (transesterification catalyst). If a certain external stimulus is applied, the crosslinking network can be reorganized, and the base resin can be recycled and reused while having self-repairing performance.

[0030] In one embodiment of the present application, the temperature of the above lamination is 150-200°C, and preferably the lamination time is 10-60 minutes.

[0031] The ester exchange reaction, i.e. crosslinking, occurs during the above lamination, and controlling the temperature between 150-200°C is beneficial to the ester exchange reaction of the adhesive film, so as to form a three-dimensional network structure.

[0032] In another typical embodiment of the present application, a photovoltaic module is provided, comprising the above encapsulating adhesive film.

[0033] The photovoltaic module comprising the encapsulating adhesive film of the present application not only maintains the excellent photoelectric conversion efficiency and service life of the base resin, but also can be re-laminated by the reversible crosslinking principle to improve the yield of the product even if the problem of bubbles and the like occurs after lamination. In addition, the encapsulating adhesive film can be melted under certain stimulation (generally heating), so as to easily separate the parts of the photovoltaic module. Not only the encapsulating adhesive film can be recycled, but also the parts (such as the cell panel, glass, back panel and the like) can be recycled without damage, thereby improving the recycling efficiency.

[0034] The beneficial effects of the present application will be described below in combination with specific examples and comparative examples.

[0035] Example 1

[0036] 100 parts of ethylene-vinyl acetate copolymer (VA content 40%, DuPont) was taken by mass fraction, 7 parts of dimethyl terephthalate, 0.5 parts of zinc acetate, 0.2 parts of 2-hydroxy-4-n-octyloxybenzophenone, 1 part of methyldiethoxysilane, 0.5 parts of decanedioic acid bis-2,2,6,6-tetramethylpiperidinol ester were added, and the above compounds were pre-mixed, melt-extruded, cast into a film, cooled, cut and rolled to prepare a reversibly crosslinkable encapsulating adhesive film, which is denoted as R1.

[0037] The tempered glass, the first encapsulating adhesive film, the cell panel (Tongwei), the second encapsulating adhesive film and the back panel were sequentially laminated in the order of the tempered glass, the first encapsulating adhesive film, the cell panel (Tongwei), the second encapsulating adhesive film and the back panel, and vacuumized (vacuum gauge pressure -0.99 atm) at 170°C to remove bubbles, and a photovoltaic module S1 was obtained after curing for 20 minutes. The first encapsulating adhesive film and the second encapsulating adhesive film were the same and were the reversibly crosslinkable encapsulating adhesive film prepared above, and the thickness of the first encapsulating adhesive film and the second encapsulating adhesive film was 0.45 mm.

[0038] Example 2

[0039] The difference from Example 1 is that 100 parts of ethylene-vinyl acetate copolymer (VA content 40%, DuPont, USA) is taken, 1 part of dimethyl terephthalate, 0.01 part of zinc acetate, 0.2 part of 2-hydroxy-4-n-octyloxy benzophenone, 1 part of methyldiethoxysilane, 0.5 part of sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester is added, the above compounds are premixed, melt-extruded, cast into a film, cooled, cut and wound to obtain a reversibly crosslinked encapsulating adhesive film, which is recorded as R2, and finally a photovoltaic module S2 is obtained.

[0040] Example 3

[0041] The difference from Example 1 is that 100 parts of ethylene-vinyl acetate copolymer (VA content 40%, DuPont, USA) is taken, 10 parts of dimethyl terephthalate, 5 parts of zinc acetate, 0.2 part of 2-hydroxy-4-n-octyloxy benzophenone, 1 part of methyldiethoxysilane, 0.5 part of sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester is added, the above compounds are premixed, melt-extruded, cast into a film, cooled, cut and wound to obtain a reversibly crosslinked encapsulating adhesive film, which is recorded as R3, and finally a photovoltaic module S3 is obtained.

[0042] Example 4

[0043] The difference from Example 1 is that 100 parts of ethylene-vinyl acetate copolymer (VA content 40%, DuPont, USA) is taken, 0.8 part of dimethyl terephthalate, 0.008 part of zinc acetate, 0.2 part of 2-hydroxy-4-n-octyloxy benzophenone, 1 part of methyldiethoxysilane, 0.5 part of sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester is added, the above compounds are premixed, melt-extruded, cast into a film, cooled, cut and wound to obtain a reversibly crosslinked encapsulating adhesive film, which is recorded as R4, and finally a photovoltaic module S4 is obtained.

[0044] Example 5

[0045] The difference from Example 1 is that the base resin is 100 parts of ethylene-acrylic acid copolymer, and the crosslinking agent is 7 parts of propylene glycol dibutyl ester to obtain an encapsulating adhesive film, which is recorded as R5, and finally a photovoltaic module S5 is obtained.

[0046] Example 6

[0047] The difference from Example 1 is that the base resin is 50 parts of ethylene-acrylic acid copolymer and 50 parts of ethylene-vinyl acetate copolymer, and the crosslinking agent is 3.5 parts of glycerol tributyrate and 3.5 parts of dimethyl terephthalate to obtain an encapsulating adhesive film, which is recorded as R6, and finally a photovoltaic module S6 is obtained.

[0048] Example 7

[0049] The difference with example 1 is that the crosslinking agent is 7 parts of trimethyl citrate, to obtain an encapsulant film, noted R7, and finally a photovoltaic module S7.

[0050] Example 8

[0051] The difference with example 1 is that the ethylene-vinyl acetate copolymer (VA content of 20%, DuPont, USA) is used to obtain an encapsulant film, noted R8, and finally a photovoltaic module S8.

[0052] Example 9

[0053] The difference with example 1 is that the ethylene-vinyl acetate copolymer (VA content of 60%, DuPont, USA) is used to obtain an encapsulant film, noted R9, and finally a photovoltaic module S9.

[0054] Example 10

[0055] The difference with example 1 is that the ethylene-vinyl acetate copolymer (VA content of 10%, DuPont, USA) is used to obtain an encapsulant film, noted R10, and finally a photovoltaic module S10.

[0056] Example 11

[0057] The difference with example 1 is that the ethylene-vinyl acetate copolymer (VA content of 70%, DuPont, USA) is used to obtain an encapsulant film, noted R11, and finally a photovoltaic module S11.

[0058] Example 12

[0059] The difference with example 1 is that the catalyst is benzenesulfonic acid to obtain an encapsulant film, noted R12, and finally a photovoltaic module S12.

[0060] Example 13

[0061] The difference with example 1 is that the UV absorber is 2-hydroxy-4-methoxybenzophenone to obtain an encapsulant film, noted R13, and finally a photovoltaic module S13.

[0062] Example 14

[0063] The difference with example 1 is that the adhesion promoter is γ-mercaptopropyltrimethoxysilane to obtain an encapsulant film, noted R14, and finally a photovoltaic module S14.

[0064] Example 15

[0065] The difference with example 1 is that the light stabilizer is 2,2,6,6-tetramethyl-4-piperidinostearate to obtain an encapsulant film, noted R15, and finally a photovoltaic module S15.

[0066] Example 16

[0067] The difference from Example 1 is that the photovoltaic module S16 can be obtained by successively stacking the tempered glass, the first encapsulating adhesive film, the battery sheet (Tongwei), the second encapsulating adhesive film, and the back plate in this order, removing bubbles at 150°C under vacuum (vacuum gauge pressure is -0.99 atm), and curing for 20 minutes.

[0068] Example 17

[0069] The difference from Example 1 is that the photovoltaic module S17 can be obtained by successively stacking the tempered glass, the first encapsulating adhesive film, the battery sheet (Tongwei), the second encapsulating adhesive film, and the back plate in this order, removing bubbles at 200°C under vacuum (vacuum gauge pressure is -0.99 atm), and curing for 20 minutes.

[0070] Example 18

[0071] The difference from Example 1 is that the photovoltaic module S18 can be obtained by successively stacking the tempered glass, the first encapsulating adhesive film, the battery sheet (Tongwei), the second encapsulating adhesive film, and the back plate in this order, removing bubbles at 140°C under vacuum (vacuum gauge pressure is -0.99 atm), and curing for 20 minutes.

[0072] Example 19

[0073] The difference from Example 1 is that the photovoltaic module S19 can be obtained by successively stacking the tempered glass, the first encapsulating adhesive film, the battery sheet (Tongwei), the second encapsulating adhesive film, and the back plate in this order, removing bubbles at 170°C under vacuum (vacuum gauge pressure is -0.99 atm), and curing for 60 minutes.

[0074] The light transmittance, yellowness, peel strength of the encapsulating adhesive film and the battery sheet, peel strength of the encapsulating adhesive film and the glass, and peel strength of the encapsulating adhesive film and the back plate of the encapsulating adhesive films obtained in Examples 1 to 19 above were tested respectively, and the results are shown in Table 1 below, wherein,

[0075] (1) The light transmittance of the encapsulating adhesive film was determined according to GB / T2410-2008;

[0076] (2) The yellowness of the encapsulating adhesive film was determined according to GB2409-80;

[0077] (3) The peel strength of the encapsulating adhesive film and the HJT battery, the peel strength of the encapsulating adhesive film and the tempered glass, and the peel strength of the encapsulating adhesive film and the back plate were all determined according to GB / T2790-1995, and the above determination results are listed in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0082] The base resin itself has a large number of acetate bonds and / or carboxyl groups, and the di(multi)carboxylic acid ester compound is added as a crosslinking agent, and under the action of a catalyst (transesterification catalyst), the crosslinking reaction of the base resin can be realized to form a reversible crosslinking network. If a certain external stimulus is given, the crosslinking network can be reorganized, and the self-repairing performance is also achieved, and the base resin can be recycled and reused. Specifically, under a certain stimulus (generally heating), the encapsulation adhesive film can be melted, and the photovoltaic module parts are easily separated. Not only the encapsulation adhesive film can be recycled, but also the other parts of the photovoltaic module (such as the cell panel, glass, back panel, etc.) can be recycled without damage, and the recycling efficiency is improved. In addition, even if the encapsulation adhesive film has problems such as bubbles after lamination, it can be laminated again through the principle of reversible crosslinking, thereby improving the yield of the product.

[0083] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A film composition, characterized in that, The film composition comprises, by weight parts: 100 parts of the matrix resin; 1 to 10 parts of crosslinking agent; and 0.01 to 5 parts of catalyst; Wherein, the crosslinking agent is a diester compound and / or a polyester compound, the catalyst is a transesterification catalyst, and the matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid copolymer; The boiling point of the crosslinking agent is greater than 150°C; The diester compounds and / or the polyester compounds are obtained by esterification of carboxylic acid compounds and alcohol compounds; The VA content in the ethylene-vinyl acetate copolymer is 20-60%; The EA content in the ethylene-ethyl acrylate copolymer, the AA content in the ethylene-acrylic acid copolymer, and the MAA content in the ethylene-methacrylic acid copolymer are each independently 20-60%; The catalyst is selected from any one or more of zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, benzenesulfonic acid, and stannous octoate; When the matrix resin is the ethylene-vinyl acetate copolymer, the crosslinking agent is crosslinking agent A, which is a dicarboxylic acid compound and / or a polycarboxylic acid compound and an alcohol compound forming a diester compound and / or a polyester compound; when the matrix resin is selected from any one or more of the ethylene-ethyl acrylate copolymer, the ethylene-acrylic acid copolymer, or the ethylene-methacrylic acid copolymer, the crosslinking agent is crosslinking agent B, which is a diol compound and / or a polyol compound and a carboxylic acid compound forming a diester compound and / or a polyester compound forming a diol compound and / or a polyester compound.

2. The film composition according to claim 1, characterized in that, The dicarboxylic acid compound is selected from C2~C3. 15 Any one or more of the following: dialiphatic carboxylic acids, terephthalic acid, and terephthalic acid.

3. The film composition according to claim 1, characterized in that, The polycarboxylic acid compound is selected from any one or more of citric acid, isocitric acid, aconitic acid, high citric acid, high isocitric acid, high aconitic acid, propane-1,2,3-tricarboxylic acid, pyromellitic acid, polyacrylic acid, and polymethacrylic acid.

4. The film composition according to claim 1, characterized in that, The alcohols are selected from C1 to C2. 15 Any one or more of the following aliphatic monohydric alcohols, benzyl alcohol, and phenylethanol.

5. The film composition according to claim 1, characterized in that, The diol compound is selected from C2~C3. 15 Any one or more of the following: dialiphatic alcohols, p-(m)phenylenediethanol.

6. The film composition according to claim 1, characterized in that, The polyol compound is selected from any one or more of glycerol and polyether polyols.

7. The film composition according to claim 1, characterized in that, The carboxylic acid compounds are selected from C1~C6. 15 Any one or more of the following aliphatic monocarboxylic acids, benzoic acid, and phenylacetic acid.

8. The film composition according to claim 1, characterized in that, When the matrix resin is selected from any one or more of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer and a mixture with the ethylene-vinyl acetate copolymer, the crosslinking agent is crosslinking agent A and / or crosslinking agent B.

9. The film composition according to any one of claims 1 to 4, characterized in that, The film composition further includes 0.1 to 0.4 parts of ultraviolet absorber.

10. The film composition according to claim 9, characterized in that, The ultraviolet absorber is selected from any one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-(2ˊ-hydroxy-5ˊ-methylphenyl)benzotriazole, and 2-hydroxy-4-methoxybenzophenone.

11. The film composition according to any one of claims 1 to 4, characterized in that, The film composition further includes 0.1 to 5 parts of a tackifier.

12. The film composition according to claim 11, characterized in that, The thickener is a silane coupling agent.

13. The film composition according to claim 12, characterized in that, The silane coupling agent is selected from any one or more of the following: methyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-triethoxysilylpropyl)disulfide, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

14. The film composition according to any one of claims 1 to 4, characterized in that, The film composition further includes 0.1 to 1.0 parts of a light stabilizer.

15. The film composition according to claim 14, characterized in that, The light stabilizer is selected from any one or more of the following: bis-2,2,6,6-tetramethylpiperidinol sebacate, 2,2,6,6-tetramethyl-4-piperidin stearate, tris(2,2,6,6-tetramethylpiperidin nitroxide radical) phosphite, tris(1,2,2,6,6-pentamethylpiperidinyl) phosphite, styrene-(2,2,6,6-tetramethylpiperidinyl) methacrylate copolymer, poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidin) succinate, and polymers of tert-octylamine triazine and ethylenediamine piperidine.

16. An encapsulating film, said encapsulating film being prepared from an encapsulating film composition through premixing, melt extrusion, casting, cooling, slitting, and winding processes, and capable of being laminated into components, characterized in that, The film composition is any one of claims 1 to 15.

17. The encapsulating film according to claim 16, characterized in that, The lamination temperature is 150~200℃.

18. The encapsulating film according to claim 16, characterized in that, The lamination time is 10~60 minutes.

19. A photovoltaic module, comprising an encapsulating film, characterized in that, The encapsulating film is the encapsulating film according to any one of claims 16 to 18.

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