Photovoltaic packaging adhesive film and preparation method and application thereof

Abstract

The invention provides a photovoltaic packaging adhesive film as well as a preparation method and application thereof. The photovoltaic packaging adhesive film is prepared from the following raw materials in parts by mass: 100 parts of a resin matrix, 0.01 to 0.5 part of lignin, 0.05 to 2 parts of a cross-linking agent, 0.05 to 5 parts of an assistant cross-linking agent, 0.01 to 1 part of a tackifier and 0.01 to 0.2 part of a light stabilizer. Lignin is used as an auxiliary agent, and the ultraviolet shielding effect can be remarkably improved. The photovoltaic adhesive film prepared by the invention has high stability and is not easy to migrate; a large number of functional groups in the lignin can chemically react with the resin to improve the crosslinking density, so that the tensile strength, resistivity and other properties of the adhesive film are improved. Lignin is used, and the method has the advantages of being environmentally friendly, non-toxic, harmless, renewable and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic modules, and relates to a photovoltaic encapsulation film, a preparation method and an application thereof, and in particular to a photovoltaic encapsulation film with high efficiency UV shielding, a preparation method and an application thereof. Background Art

[0002] Photovoltaic encapsulation film, a key material in photovoltaic modules, impacts module quality and lifespan. As an organic polymer, it ages under prolonged sunlight exposure, reducing the film's adhesion, light transmittance, and mechanical strength, impacting module lifespan and power generation efficiency. Furthermore, the backsheet of a module can age and crack over time, primarily due to UV radiation exposure. Therefore, developing a highly stable, UV-shielding photovoltaic film to reduce UV exposure to the backsheet is an effective way to slow backsheet aging and extend module lifespan.

[0003] In order to improve the UV shielding ability of photovoltaic films, additives with UV shielding effect are usually added to the films. Commonly used UV shielding agents include inorganic and organic types. Organic types such as benzophenones and benzotriazoles have obvious absorption of ultraviolet rays in the range of 290 to 380 nm. They are the most commonly used ultraviolet absorbers in photovoltaic films. For example, the ultraviolet absorbers commonly used in the prior art include 2-hydroxy-4-octyloxybenzophenone, 2,2-tetramethylenebis(3,1-benzoxazine-4-one), 2-(2'-hydroxy-5-methylphenyl)benzotriazole, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazole-2)-4,6-bis(1-methyl-1-phenylethyl)phenol, etc. However, the disadvantage of these UV absorbers being easily degraded under light makes the components unstable; inorganic types such as titanium dioxide and zinc oxide have excellent scattering properties for ultraviolet rays, but they easily cause photodegradation of polymers and are generally not used in photovoltaic films.

[0004] Therefore, in this field, it is expected to further improve the anti-ultraviolet aging performance of photovoltaic encapsulation films, improve the migration properties, and enhance the tensile strength, resistivity and other properties of the films. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a photovoltaic encapsulation film and a preparation method and application thereof.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a photovoltaic encapsulation film, and the raw materials for preparing the photovoltaic encapsulation film include the following components in parts by mass: 100 parts by mass of a resin matrix, 0.01 to 0.5 parts by mass of lignin, 0.05 to 2 parts by mass of a cross-linking agent, 0.05 to 5 parts by mass of a co-cross-linking agent, 0.01 to 1 parts by mass of a tackifier, and 0.01 to 0.2 parts by mass of a light stabilizer.

[0008] This invention uses the biomass material lignin as a special additive to improve the UV aging resistance of photovoltaic encapsulation films. First, the abundant benzene rings and their derivatives in lignin's structure give it excellent UV absorption capabilities. Second, compared to commonly used UV absorbers, lignin's rich functional groups can chemically bond with the resin matrix, allowing it to be stable in the film and less susceptible to migration. Third, lignin's high chemical activity increases the resin's crosslinking density, improving the film's tensile strength, resistivity, and other properties.

[0009] In the present invention, the renewable raw material lignin added to the photovoltaic film has a large number of benzene ring structures. The π electron cloud in the benzene ring can absorb ultraviolet light and produce electron transitions. Because the lignin structure contains a large number of different types of benzene ring derivatives, its π electron cloud has a variety of energy level distributions, which enables lignin to absorb ultraviolet light of multiple wavelengths. Therefore, the photovoltaic film can absorb all ultraviolet light in the wavelength range of 290nm to 380nm.

[0010] In the present invention, the amount of lignin in the raw materials for preparing the photovoltaic encapsulation film can be 0.01 mass parts, 0.05 mass parts, 0.1 mass parts, 0.2 mass parts, 0.3 mass parts, 0.4 mass parts or 0.5 mass parts; the amount of the cross-linking agent can be 0.05 mass parts, 0.08 mass parts, 0.1 mass parts, 0.5 mass parts, 0.8 mass parts, 1 mass part, 1.3 mass parts, 1.5 mass parts, 1.8 mass parts or 2 mass parts; the amount of the auxiliary cross-linking agent can be 0.05 mass parts, 0.08 mass parts, 0.1 mass parts, 0.5 mass parts, 0.8 mass parts, 1 mass part, 1.3 mass parts, 1.5 mass parts, 1.8 mass parts or 2 mass parts. The amount of the tackifier can be 0.01 mass part, 0.03 mass part, 0.05 mass part, 0.08 mass part, 0.1 mass part, 0.3 mass part, 0.5 mass part, 0.8 mass part or 1 mass part, and the amount of the light stabilizer can be 0.01 mass part, 0.05 mass part, 0.1 mass part, 0.15 mass part, 0.18 mass part or 0.2 mass part.

[0011] Preferably, the resin matrix is one or a combination of at least two of ethylene-vinyl acetate copolymer, ethylene copolymer, propylene copolymer, ethylene-butene copolymer or ethylene-octene copolymer, preferably ethylene-vinyl acetate copolymer or ethylene-octene copolymer.

[0012] Preferably, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 10-33%, for example, 10%, 13%, 15%, 20%, 23%, 25%, 28%, 30% or 33%, preferably 28-33%; the melt index is 10-43 g / 10min, for example, 10 g / 10min, 15 g / 10min, 18 g / 10min, 20 g / 10min, 25 g / 10min, 28 g / 10min, 30 g / 10min, 33 g / 10min, 38 g / 10min, 40 g / 10min or 43 g / 10min, preferably 15-25 g / 10min.

[0013] Preferably, the melt index of the ethylene-octene copolymer is 3 to 30 g / 10 min, for example, 3 g / 10 min, 5 g / 10 min, 8 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min or 30 g / 10 min, preferably 5 to 15 g / 10 min.

[0014] In the present invention, the lignin is alkaline lignin or neutral lignin.

[0015] Preferably, the alkaline lignin is selected from at least one of kraft lignin, alkali lignin, oxygen alkali lignin, ammonia lignin or lime lignin.

[0016] Preferably, the neutral lignin is selected from at least one of Bross natural lignin, Nord lignin, Beckmann lignin or cellulolytic enzyme lignin.

[0017] More preferably, the lignin is Brown natural lignin or alkali lignin.

[0018] In the present invention, acidic lignin is not used, because adding acidic lignin can achieve a UV shielding effect, but the transmittance of the photovoltaic encapsulation film will be significantly reduced, making it not meet the application requirements of the photovoltaic film, and its acidity will aggravate the acid corrosion of the backplane and make the backplane yellow.

[0019] Preferably, the lignin is powdered lignin obtained by drying.

[0020] More preferably, the drying method is spray drying.

[0021] Preferably, the cross-linking agent is tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1, The present invention is a mixture of one or more of 1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl 2,5-bis(benzoylperoxy)-hexane, tert-amyl peroxycarbonate, and tert-butyl peroxy-3,3,5-trimethylhexanoate, and is preferably any one or a combination of at least two of tert-butylperoxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

[0022] Preferably, the auxiliary crosslinking agent is triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate. The invention is a mixture of one or more of acrylate, 2,4,6-tris(2-propenyloxy)-1,3,5-triazine, tricyclodecane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate and polyethylene glycol dimethacrylate, preferably any one of triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate or propoxylated trimethylolpropane triacrylate or a combination of at least two thereof.

[0023] Preferably, the tackifier is a silane coupling agent, specifically a mixture of one or more of vinyl triethoxysilane, vinyl trimethoxysilane, vinyl tri(β-methoxyethoxy) silane, methacryloxypropyl trimethoxysilane, aminopropyl trimethoxysilane, aminopropyl triethoxysilane, and aminopropyl triisopropoxysilane, preferably any one of methacryloxypropyl trimethoxysilane or vinyl trimethoxysilane or a combination of at least two.

[0024] Preferably, the light stabilizer is 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, tris (1,2,2,6,6-pentamethyl-4-piperidinyl) phosphite, bis-2,2,6,6-tetramethylpiperidinol sebacate, bis-1-decyloxy-2,2,6,6-tetramethylpiperidin-4-ol sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, N,N'-bis Polymers of (2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and morpholine-2,4,6-trichloro-1,3,5-triazine, 1,5,8,12-tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazin-2-yl]-1,5,8,12-tetraazadodecane, poly-{[6-[(1,1,3,3-tetramethylbutyl) one or a combination of at least two of [4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2,4-diyl] [2-(2,2,6,6-tetramethylpiperidinyl)-nitro]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]}, preferably 1,5,8,12-tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2,4-diyl] -yl]-1,5,8,12-tetraazadodecane, poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitro]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or bis-2,2,6,6-tetramethylpiperidinol sebacate or a combination of at least two thereof.

[0025] In another aspect, the present invention provides a method for preparing the photovoltaic encapsulation film as described above, the method comprising the following steps:

[0026] The resin matrix, lignin, a cross-linking agent, a co-cross-linking agent, a tackifier and a light stabilizer are mixed, melt-extruded and cast into a film to obtain the photovoltaic encapsulation film.

[0027] In the present invention, the photovoltaic encapsulation film is prepared by cooling, slitting, winding and other processes after the cast film is formed.

[0028] In another aspect, the present invention provides use of the photovoltaic encapsulation film described above in a photovoltaic module.

[0029] The high-efficiency UV-shielding photovoltaic adhesive film prepared by the present invention has high stability and high UV-shielding effect, can greatly reduce the UV radiation received by the backboard, and is an effective means to delay the aging of the backboard and increase the service life of the component.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention utilizes lignin as an auxiliary agent. The lignin structure is rich in benzene rings and their derivatives, which have excellent absorption effects on ultraviolet light and can significantly improve the ultraviolet shielding effect. The photovoltaic film prepared by the present invention has high stability. On the one hand, compared with commonly used ultraviolet absorbers, the lignin structure has abundant functional groups that can chemically combine with the resin matrix, making it less likely to migrate. On the other hand, its large number of functional groups can chemically react with the resin to increase the crosslinking density, thereby improving the tensile strength, resistivity and other properties of the film. The lignin used in the present invention is the second largest biomass resource in plants and has the advantages of being green, environmentally friendly, non-toxic, harmless, and renewable. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0033] Example 1

[0034] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of EVA with a VA content of 28% (Hanwha Total Energy), 0.05 parts by mass of Brousson lignin, 0.5 parts by mass of tert-butyl peroxycarbonate-2-ethylhexyl ester (Unaid Initiator (Shanghai) Co., Ltd., TBEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Basf, Germany, Tinuvin 770), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (Evonik Degussa, KH-570).

[0035] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0036] Example 2

[0037] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of EVA with a VA content of 28% (Hanwha Total Energy), 0.1 parts by mass of Brousson lignin, 0.5 parts by mass of tert-butyl peroxycarbonate-2-ethylhexyl ester (Unaid Initiator (Shanghai) Co., Ltd., TBEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (BASF, Germany, Tinuvin 770), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (Evonik Degussa, KH-570).

[0038] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0039] Example 3

[0040] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of EVA with a VA content of 28% (Hanwha Total Energy), 0.2 parts by mass of Brousson lignin, 0.5 parts by mass of tert-butyl peroxycarbonate-2-ethylhexyl ester (Unaid Initiator (Shanghai) Co., Ltd., TBEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Basf, Germany, Tinuvin 770), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (Evonik Degussa, KH-570).

[0041] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0042] Example 4

[0043] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of ethylene-octene copolymer (Dow Chemical), 0.05 parts by mass of Brousson lignin, 0.5 parts by mass of tert-amyl peroxy-2-ethylhexyl carbonate (Unaid Initiator (Shanghai) Co., Ltd., TAEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Tinuvin 770, BASF, Germany), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (KH-570, Evonik Degussa).

[0044] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0045] Example 5

[0046] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of ethylene-octene copolymer (Dow Chemical), 0.1 parts by mass of Brousson lignin, 0.5 parts by mass of tert-amyl peroxy-2-ethylhexyl carbonate (Unaid Initiator (Shanghai) Co., Ltd., TAEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Tinuvin 770, BASF, Germany), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (KH-570, Evonik Degussa).

[0047] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0048] Example 6

[0049] A high-efficiency UV-shielding photovoltaic encapsulation film, the preparation raw materials of which include: 100 parts by mass of ethylene-octene copolymer (Dow Chemical), 0.2 parts by mass of Brousson lignin, 0.5 parts by mass of tert-amyl peroxy-2-ethylhexyl carbonate (Unaid Initiator (Shanghai) Co., Ltd., TAEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Tinuvin 770, BASF, Germany), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (KH-570, Evonik Degussa).

[0050] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, and the extruded materials are melted and plasticized and then injected into a die head. After the processes of cast film, cooling, slitting, and winding, a high-efficiency UV-shielding photovoltaic encapsulation film is prepared.

[0051] Comparative Example 1

[0052] A photovoltaic encapsulation film, prepared from raw materials including: 100 parts by mass of EVA with a VA content of 28% (Hanwha Total Energy), 0.5 parts by mass of tert-butyl peroxycarbonate-2-ethylhexyl ester (Unaid Initiator (Shanghai) Co., Ltd., TBEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.2 parts by mass of 2-hydroxy-4-n-octyloxybenzophenone (BASF, Germany), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (BASF, Germany, Tinuvin 770), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (Evonik Degussa, KH-570).

[0053] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, the extruded materials are melted and plasticized and then injected into a die head, and the nanocellulose reinforced photovoltaic encapsulation film is prepared through the processes of melt extrusion, cast film, cooling, slitting, and winding.

[0054] Comparative Example 2

[0055] A photovoltaic encapsulation film, prepared from the following raw materials: 100 parts by mass of ethylene-octene copolymer (Dow Chemical, USA), 0.5 parts by mass of tert-amyl peroxy-2-ethylhexyl carbonate (Unaid Initiator (Shanghai) Co., Ltd., TAEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.2 parts by mass of 2-hydroxy-4-n-octyloxybenzophenone (BASF, Germany), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (BASF, Germany, Tinuvin 770), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (Evonik Degussa, KH-570).

[0056] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, the extruded materials are melted and plasticized and then injected into a die head, and the nanocellulose reinforced photovoltaic encapsulation film is prepared through the processes of melt extrusion, cast film, cooling, slitting, and winding.

[0057] Comparative Example 3

[0058] A photovoltaic encapsulation film, prepared from raw materials including: 100 parts by mass of EVA with a VA content of 28% (Hanwha Total Energy), 0.2 parts by mass of sulfated lignin, 0.5 parts by mass of tert-butyl peroxycarbonate-2-ethylhexyl ester (Unaid Initiator (Shanghai) Co., Ltd., TBEC), 3.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Tianjin Tianjiao Chemical Co., Ltd.), 0.1 parts by mass of bis-2,2,6,6-tetramethylpiperidinol sebacate (Tinuvin 770, BASF, Germany), and 0.2 parts by mass of methacryloyloxypropyltrimethoxysilane (KH-570, Evonik Degussa).

[0059] The above raw materials are mixed evenly in a stirring kettle, blended and extruded through an extruder, the extruded materials are melted and plasticized and then injected into a die head, and the nanocellulose reinforced photovoltaic encapsulation film is prepared through the processes of melt extrusion, cast film, cooling, slitting, and winding.

[0060] Performance testing method:

[0061] 1. Light transmittance test:

[0062] The test sample thickness is 0.6 mm. According to the spectrophotometer method of GB / T 2410-2008, the average transmittance in the range of 380-1100 nm and the range of 290-380 nm is taken.

[0063] 2. Cross-linking degree test:

[0064] Sample preparation is as follows: Take a 50mm x 50mm piece of adhesive film and stack it, from bottom to top, on top of glass, non-stick film, adhesive film, non-stick film, and finally glass. Place it in a vacuum laminator for curing and crosslinking. Remove the film and cool it to room temperature in a desiccator before use. The cured film must be flat and uniform in thickness, with a crosslinking degree of at least 75%. Weigh 0.50g ± 0.01g and cut it into small pellets smaller than 3mm x 3mm. Each set of samples should contain at least three.

[0065] The test method is as follows: a. Wash and dry the stainless steel mesh bag, and weigh it as W1 (accurate to 0.001g); b. Place the prepared sample in the stainless steel mesh bag, and weigh it as W2 (accurate to 0.001g); c. Seal the mesh bag with wire, place it in a three-necked flask filled with 1 / 2 volume of xylene solution, immerse the sample in the solvent, heat it to about 140°C, and condense and reflux for 5h; d. After the reflux is completed, take out the stainless steel mesh bag, hang it to remove droplets, and place it in a vacuum oven at 140°C, dry it to constant weight; e. Take out the stainless steel mesh bag, remove the wire, and place it in a desiccator to cool to room temperature, and weigh it as W3 (accurate to 0.001g).

[0066] The calculation method is as follows: Calculate the degree of cross-linking according to the following formula and take the average value of the test results.

[0067] D=(W3-W1) / (W2-W1)*100%

[0068] Where D is the degree of cross-linking; W1 is the mass of the empty stainless steel wire mesh bag / g; W2 is the mass of the wire mesh containing the sample / g; W3 is the mass of the sample and wire mesh after extraction and drying / g.

[0069] 3. Back panel protection effect test:

[0070] Using film to encapsulate standard single-glass photovoltaic modules, after the UV80kWh test, the backsheet was observed for cracking and chalking, and the Δb value was measured using a colorimeter. If the backsheet showed no cracking or chalking, and Δb < 2, the backsheet protection was considered acceptable; otherwise, the protection was considered NG.

[0071] The test results of all samples are shown in Table 1.

[0072] Table 1 Performance test results of the embodiments and comparative examples

[0073]

[0074]

[0075] The applicant declares that while the above-described embodiments illustrate the photovoltaic encapsulation film, its preparation method, and its application, the present invention is not limited to these embodiments, nor does it necessarily rely on these embodiments for implementation. Persons skilled in the art should understand that any improvements to the present invention, equivalent substitutions for raw materials in the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A photovoltaic encapsulation film, characterized in that: The raw materials for preparing the photovoltaic encapsulation film include the following components in parts by mass: 100 parts by mass of a resin matrix, 0.01 to 0.5 parts by mass of lignin, 0.05 to 2 parts by mass of a cross-linking agent, 0.05 to 5 parts by mass of a co-cross-linking agent, 0.01 to 1 parts by mass of a tackifier, and 0.01 to 0.2 parts by mass of a light stabilizer.

2. The photovoltaic encapsulation film according to claim 1, characterized in that: The resin matrix is one or a combination of at least two of ethylene-vinyl acetate copolymer, ethylene copolymer, propylene copolymer, ethylene-butene copolymer or ethylene-octene copolymer, preferably ethylene-vinyl acetate copolymer or ethylene-octene copolymer; Preferably, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 10 to 33%, preferably 28 to 33%, and the melt index is 10 to 43 g / 10 min, preferably 15 to 25 g / 10 min; Preferably, the melt index of the ethylene-octene copolymer is 3 to 30 g / 10 min, preferably 5 to 15 g / 10 min.

3. The photovoltaic encapsulation film according to claim 1 or 2, characterized in that: The lignin is alkaline lignin or neutral lignin. Preferably, the alkaline lignin is selected from at least one of kraft lignin, alkali lignin, oxygen alkali lignin, ammonia lignin or lime lignin; Preferably, the neutral lignin is selected from at least one of Bross natural lignin, Nord lignin, Beckmann lignin or cellulolytic enzyme lignin; Preferably, the lignin is Brown's natural lignin or alkali lignin.

4. The photovoltaic encapsulation film according to any one of claims 1 to 3, characterized in that: The lignin is powdered lignin obtained by drying; More preferably, the drying method is spray drying.

5. The photovoltaic encapsulation film according to any one of claims 1 to 4, characterized in that: The crosslinking agent is tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1- The present invention is a mixture of one or more of bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl 2,5-bis(benzoylperoxy)-hexane, tert-amyl peroxycarbonate, and tert-butyl peroxy-3,3,5-trimethylhexanoate, and is preferably any one or a combination of at least two of tert-butylperoxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

6. The photovoltaic encapsulation film according to any one of claims 1 to 5, characterized in that: The auxiliary crosslinking agent is triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate. The invention relates to a mixture of one or more of ester, 2,4,6-tris(2-propenyloxy)-1,3,5-triazine, tricyclodecane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate and polyethylene glycol dimethacrylate, preferably any one of triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate or propoxylated trimethylolpropane triacrylate or a combination of at least two thereof.

7. The photovoltaic encapsulation film according to any one of claims 1 to 6, characterized in that: The tackifier is a silane coupling agent, specifically a mixture of one or more of vinyl triethoxysilane, vinyl trimethoxysilane, vinyl tri(β-methoxyethoxy) silane, methacryloxypropyl trimethoxysilane, aminopropyl trimethoxysilane, aminopropyl triethoxysilane, and aminopropyl triisopropoxysilane, preferably any one of methacryloxypropyl trimethoxysilane or vinyl trimethoxysilane or a combination of at least two thereof.

8. The photovoltaic encapsulation film according to any one of claims 1 to 7, characterized in that: The light stabilizer is 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, tris (1,2,2,6,6-pentamethyl-4-piperidinyl) phosphite, bis-2,2,6,6-tetramethylpiperidinol sebacate, bis-1-decyloxy-2,2,6,6-tetramethylpiperidin-4-ol sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, N,N'-bis (2, Polymer of 2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and morpholine-2,4,6-trichloro-1,3,5-triazine, 1,5,8,12-tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazin-2-yl]-1,5,8,12-tetraazadodecane, poly-{[6-[(1,1,3,3-tetramethylbutyl) -imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitro]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or a combination of at least two thereof, preferably 1,5,8,12-tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2,4-diyl] [0015] The present invention relates to a method for preparing an aqueous solution of a poly(vinyl alcohol)-containing product comprising: preparing an aqueous solution of poly(vinyl alcohol)-containing product; and preparing the aqueous solution of poly(vinyl alcohol)-containing product. The method comprises the steps of: preparing an aqueous solution of poly(vinyl alcohol)-containing product and preparing the aqueous solution of poly(vinyl alcohol)-containing product.

9. A method for preparing a photovoltaic encapsulation film according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: The resin matrix, lignin, a cross-linking agent, a co-cross-linking agent, a tackifier and a light stabilizer are mixed, melt-extruded and cast into a film to obtain the photovoltaic encapsulation film.

10. Use of the photovoltaic encapsulation film according to any one of claims 1 to 8 in photovoltaic modules.

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