Solar packaging adhesive film as well as preparation process and application thereof

Abstract

The invention relates to the technical field of solar cell materials, in particular to a solar packaging adhesive film and a preparation process and application thereof. Comprising the following raw materials in parts by weight: 80 to 100 parts of EVA resin, 20 to 30 parts of modified polylactic acid, 40 to 80 parts of modified polyvinyl chloride, 0.5 to 2 parts of a cross-linking agent, 0.5 to 2 parts of an assistant cross-linking agent, 0.05 to 1 part of a light stabilizer, 0.05 to 1.5 parts of a stabilizer, 0.5 to 1.5 parts of an ultraviolet absorbent, 0.3 to 1.2 parts of a silane coupling agent, 2.5 to 8.5 parts of nano filler and 0.5 to 2.5 parts of an ionic liquid additive. The nano filler comprises perovskite quantum dots, nano calcium carbonate and nano titanium dioxide, and the mass ratio of the perovskite quantum dots to the nano calcium carbonate to the nano titanium dioxide is 1: (1-3): (1-2); the ionic liquid additive is 1-butyl-3-methylimidazolium hexafluorophosphate, and the ionic liquid additive is 1-butyl-3-methyl imidazole hexafluorophosphate.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell materials, and more particularly to a solar encapsulation film and a preparation process and application thereof. Background Art

[0002] With the continuous emergence of new materials and processes, the performance of photovoltaic films will be further enhanced to meet the needs of more complex and demanding application scenarios. Currently, the main encapsulation films on the market include EVA (ethylene-vinyl acetate copolymer), POE (polyolefin elastomer), EPE (EVA-POE-EVA co-extruded polyolefin), PVB (polyvinyl butyral), and TPO (thermoplastic polyolefin). Due to the higher processing costs of PVB and the inferior light transmittance, water vapor permeability, and adhesion properties of TPO compared to EVA and POE, EVA film remains the mainstream material in the photovoltaic encapsulation film market. However, with N-type cells becoming the main direction of future solar cell development, the iteration of battery encapsulation film technology is accelerating. POE film and multi-layer co-extruded film (EPE) are attracting increasing market demand due to their superior performance, and are rapidly replacing EVA film.

[0003] EVA film will produce acetic acid under the combined effects of humidity, heat, ultraviolet light and oxygen, and acetic acid will react chemically with the sodium salt in the glass, resulting in Na + Migration of the components can cause PID (potential-induced degradation). EPE film combines the advantages of both EVA and POE films while addressing their shortcomings, offering a wider range of combination options. This allows component manufacturers to avoid choosing solely high-cost pure POE encapsulation films or pure EVA encapsulation films with their high water vapor permeability, low volume resistivity, and high quality assurance, thereby achieving a more comprehensive and economical encapsulation effect.

[0004] The primary component of EVA film is ethylene-vinyl acetate copolymer (EVA resin), a polymer material produced through the copolymerization of ethylene and vinyl acetate. Depending on the vinyl acetate (VA) content, EVA film can exhibit either plastic or rubber properties. A VA content below 20% is plastic, while a VA content above 30% is rubber. In photovoltaic modules, EVA film typically uses EVA resin with a VA content of 28-33% to ensure excellent light transmittance and weather resistance.

[0005] However, the EVA film in the prior art still has the following deficiencies: (1) EVA film is prone to aging when exposed to ultraviolet rays, high temperature and humid environment for a long time, which manifests as yellowing, strength loss, cracking and blistering; (2) EVA film is prone to molecular chain breakage under ultraviolet irradiation, producing gas byproducts, causing blistering or delamination of the film; (3) EVA film is prone to PID phenomenon in double-glass modules, that is, water vapor penetration causes corrosion of the cell, affecting the long-term stability of the module. Summary of the Invention

[0006] The present invention provides a solar encapsulation film, a preparation process and application thereof. By adding multiple auxiliary agents such as modified polyvinyl chloride, a cross-linking agent, a co-cross-linking agent and a light stabilizer, the auxiliary agents work together to make the prepared solar encapsulation film have high light transmittance, good adhesion, weather resistance, UV resistance and aging resistance.

[0007] In a first aspect, the present invention provides a solar encapsulation film, comprising the following raw materials in parts by weight: 80-100 parts of EVA resin, 20-30 parts of modified polylactic acid, 40-80 parts of modified polyvinyl chloride, 0.5-2 parts of a crosslinking agent, 0.5-2 parts of a co-crosslinking agent, 0.05-1 parts of a light stabilizer, 0.05-1.5 parts of a stabilizer, 0.5-1.5 parts of a UV absorber, 0.3-1.2 parts of a silane coupling agent, 2.5-8.5 parts of a nanofiller, and 0.5-2.5 parts of an ionic liquid additive; the nanofiller comprises perovskite quantum dots, nano-calcium carbonate, and nano-titanium dioxide, and the mass ratio of the perovskite quantum dots, nano-calcium carbonate, and nano-titanium dioxide is 1:1-3:1-2; and the ionic liquid additive is 1-butyl-3-methylimidazole hexafluorophosphate.

[0008] Preferably, the modified polyvinyl chloride is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate for blending.

[0009] Preferably, the mass ratio of the polyvinyl chloride, acrylic acid and dioctyl phthalate is 1:1-5:2-3.

[0010] Preferably, the modified polylactic acid is prepared by blending ethylene-vinyl alcohol copolymer with polylactic acid, and then compounding with ammonium polyphosphate. The mass ratio of the ethylene-vinyl alcohol copolymer, polylactic acid and ammonium polyphosphate is 1-2:5-8:3-5.

[0011] Preferably, the stabilizer is a lanthanum dipentaerythritol rare earth metal alkoxide, which is prepared using dipentaerythritol, maleic acid and lanthanum acetate as raw materials, and the mass ratio of the dipentaerythritol, maleic acid and lanthanum acetate is 1-2:3-5:1-3.

[0012] Preferably, the light stabilizer is bis-2,2,6,6-tetramethylpiperidinol sebacate.

[0013] Preferably, the ultraviolet absorber comprises lignin and 2-hydroxy-4-n-oxybenzophenone, and the mass ratio of the lignin to the 2-hydroxy-4-n-oxybenzophenone is 1-2:3-5.

[0014] Preferably, the cross-linking agent is one or more of tert-butyl peroxy-2-ethylhexyl carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, dicumyl peroxide, and triallyl isocyanurate.

[0015] Preferably, the auxiliary cross-linking agent is one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane triacrylate, 3(ethoxy)trimethylolpropane triacrylate, and glycerol trihydroxypropyl ether triacrylate.

[0016] Preferably, the silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane, 3-(methacryloxy)propyltrimethoxysilane, and vinyltrimethoxysilane.

[0017] In a second aspect, the present invention provides a process for preparing a solar encapsulation film, comprising the following steps: (1) The mixed material is layered to prepare a gradient functionalized adhesive film, wherein the gradient functionalized adhesive film comprises a surface layer, an intermediate layer and a bottom layer, wherein the surface layer is prepared from EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent, the intermediate layer is prepared from modified polyvinyl chloride and ionic liquid additive, and the bottom layer is prepared from silane coupling agent enrichment; (2) The surface layer is prepared by copolymerization of EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent; (3) The middle layer is made of modified polyvinyl chloride and ionic liquid additives through ionic interaction; (4) The bottom layer is prepared by enriching the silane coupling agent; (5) The gradient functionalized film is melt-extruded through a multi-layer co-extrusion technology, melted at high temperature, and extruded through an extruder. The extrusion line is equipped with a screen changer, a metering pump, and a die head.

[0018] (6) Embossing: Use an embossing roller to press patterns on the surface of the film in a physical mode to increase the friction of the film.

[0019] (7) Tempering: The extruded film is irradiated with high temperature by infrared lamps to eliminate stress.

[0020] (8) Cooling: Use rubber roller / steel roller cooling mode and natural cooling through production line to finalize the product shape.

[0021] (9) Online thickness detection: Scan the film in real time to detect thickness and adjust the process according to the thickness distribution trend.

[0022] (10) Online defect detection: Scan the film in real time to monitor appearance defects, automatically identify defects, classify them and mark their coordinates.

[0023] (11) Slitting and rewinding: Slitting and rewinding according to the set product width and length.

[0024] (12) Packaging: Pack, palletize and label the roll film packaging according to the packaging operation requirements.

[0025] In a third aspect, the present invention provides a solar cell assembly, wherein the solar cell assembly comprises the solar encapsulation film.

[0026] In summary, the present invention has the following beneficial effects: The modified polyvinyl chloride in the present invention is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate to blend. The technical principle of the blending modification of acrylic acid grafted polyvinyl chloride and dioctyl phthalate is to introduce acrylic acid and its ester monomers into the polyvinyl chloride molecular chain through a chemical grafting reaction to form a graft copolymer with polar side chains, thereby improving its compatibility and performance. The addition of modified polyvinyl chloride to EVA resin improves the toughness of EVA through multi-dimensional synergistic optimization. The formed graft copolymer forms a network structure, which improves the tensile strength of the material and effectively resists the mechanical stress during the component lamination process. Heterocyclic compounds in the modified polyvinyl chloride, such as benzothiazole, can absorb ultraviolet rays and scavenge free radicals, and cooperate with EVA light stabilizers to extend the weathering life of the components.

[0027] The present invention adds nanofillers including perovskite quantum dots, nano-calcium carbonate, and nano-titanium dioxide, and introduces new functional additives. The perovskite quantum dots are combined with the polymer material EVA in the encapsulation film to effectively reduce their contact with environmental factors such as air and water, thereby improving their chemical stability and thermal stability. Perovskite quantum dots can achieve light wavelength conversion in the encapsulation film, converting high-energy ultraviolet light that cannot be directly absorbed by solar cells into visible light, thereby improving the photoelectric conversion efficiency of solar cells. Perovskite quantum dots affect the dispersibility and compatibility of the matrix material in the encapsulation film. By optimizing the encapsulation material and preparation process, the uniformity of the quantum dots in the film can be improved, agglomeration can be reduced, and the photoelectric conversion efficiency of the device can be improved.

[0028] In the present invention, nano-calcium carbonate is used as a filler and can act as a nucleating agent to improve the mechanical properties of EVA. Nano-calcium carbonate can also enhance the reinforcement effect of EVA, increasing its tensile strength and elongation at break. The addition of nano-titanium dioxide to EVA can improve its UV resistance and thermal stability. By forming a bonding structure with a silane coupling agent, nano-TiO2 can be more evenly dispersed in the EVA matrix, thereby improving the mechanical properties and processing fluidity of the material. Nano-calcium carbonate and nano-titanium dioxide work synergistically in the EVA film, forming a bonding network with the silane coupling agent, and simultaneously improving strength and weather resistance, respectively playing an important role in mechanical properties, thermal stability, UV resistance, and electrical conductivity.

[0029] The present invention adds a stabilizer dipentaerythritol lanthanum rare earth metal alkoxide, dipentaerythritol (star polyol) as a ligand, and lanthanum (La 3+ ) forms metal alkoxides. The unique star-shaped structure provides multiple active sites, enhancing interactions with polymer chains. Lanthanum ions displace weak bonds in the vinyl acetate segments of EVA, reducing free radicals generated by thermal decomposition. They also capture and neutralize acidic byproducts such as acetic acid produced by acetic acid removal, inhibiting autocatalytic degradation. They also synergize with light stabilizers to achieve UV shielding and conversion. The ff transition of lanthanides absorbs UV light and converts it into harmless heat or visible light. EVA modified with rare earth complexes delays yellowing and reduces transmittance decay in wet heat and UV tests.

[0030] The present invention incorporates an ionic liquid additive, 1-butyl-3-methylimidazolium hexafluorophosphate. The ionic liquid improves the elastic modulus and fracture toughness of the encapsulation film. The alkyl chains (butyl and methyl) in 1-butyl-3-methylimidazolium hexafluorophosphate bond to the carbon chains of the modified polyvinyl chloride (PVC) through van der Waals and intermolecular forces, rather than typical chemical bonding. This interaction enhances the flexibility of the PVC molecular chain and improves material processing properties. 1-butyl-3-methylimidazolium hexafluorophosphate, used for interfacial modification, reduces charge recombination, increases open-circuit voltage, and suppresses potential-induced component degradation.

[0031] This invention creates a gradient functionalized film through layering. Multilayer co-extrusion technology offers design flexibility and cost-effectiveness, enabling the production of superior materials. By integrating the strengths of different materials, material performance is optimized. Multilayer co-extrusion combines the triple functions of nano-modification (TiO2), elastomer toughening (POE / PVC), and interfacial coupling (silane), achieving a gradient performance transition from UV resistance to high toughness to strong adhesion.

[0032] The preparation process of this invention utilizes a ribbon mixer for high-speed mixing, improving mixing efficiency and enhancing mixing uniformity. A central feeding system centrally stores and delivers ingredients to designated production lines, reducing losses and impurities during vacuum feeding and increasing conveying efficiency. A current measurement system and melt pump monitor and control material pressure, enabling plasticization under high pressure to enhance strength and dispersion. Steel and rubber rollers are used to emboss the film surface, increasing friction and preventing sticking. A film defect detection system and static elimination device are employed to enhance product quality control.

[0033] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the scope of protection of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a process flow chart of the solar encapsulation film of the present invention; Figure 2 This is a sample picture of the solar encapsulation film of the present invention. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions were carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources. Example

[0036] Example 1: A solar encapsulation film comprising the following raw materials in parts by weight: 80 parts of EVA resin, 20 parts of modified polylactic acid, 40 parts of modified polyvinyl chloride, 0.5 parts of crosslinking agent, 0.5 parts of co-crosslinking agent, 0.05 parts of light stabilizer, 0.05 parts of stabilizer, 0.5 parts of UV absorber, 0.3 parts of silane coupling agent, 2.5 parts of nanofiller, and 0.5 parts of ionic liquid additive; The nanofiller includes perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide, and the mass ratio of the perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide is 1:1:1; The ionic liquid additive is 1-butyl-3-methylimidazolium hexafluorophosphate; The modified polyvinyl chloride is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate for blending; the mass ratio of polyvinyl chloride, acrylic acid and dioctyl phthalate is 1:1:2.

[0037] The modified polylactic acid is prepared by blending ethylene-vinyl alcohol copolymer with polylactic acid and then compounding with ammonium polyphosphate. The mass ratio of ethylene-vinyl alcohol copolymer, polylactic acid and ammonium polyphosphate is 1:5:3.

[0038] The stabilizer is dipentaerythritol lanthanum rare earth metal alkoxide, which is prepared by using dipentaerythritol, maleic acid and lanthanum acetate as raw materials, and the mass ratio of dipentaerythritol, maleic acid and lanthanum acetate is 1:3:1.

[0039] The light stabilizer is bis-2,2,6,6-tetramethylpiperidinol sebacate.

[0040] The ultraviolet absorber comprises lignin and 2-hydroxy-4-n-oxybenzophenone, and the mass ratio of lignin to 2-hydroxy-4-n-oxybenzophenone is 1:3.

[0041] The crosslinking agent is tert-butyl peroxycarbonate-2-ethylhexyl ester; The auxiliary crosslinking agent includes 0.1 part of triallyl isocyanurate, 0.1 part of trimethylolpropane triacrylate, 0.1 part of trimethylolpropane triacrylate, 0.3 part of 3 (ethoxy) trimethylolpropane triacrylate, and 0.3 part of glycerol trihydroxypropyl ether triacrylate; The silane coupling agent is γ-methacryloxypropyltrimethoxysilane; A process for preparing a solar encapsulation film comprises the following steps: (1) The mixed material is layered to prepare a gradient functionalized adhesive film, wherein the gradient functionalized adhesive film comprises a surface layer, an intermediate layer and a bottom layer, wherein the surface layer is prepared from EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent, the intermediate layer is prepared from modified polyvinyl chloride and ionic liquid additive, and the bottom layer is prepared from silane coupling agent enrichment; (2) The surface layer is prepared by copolymerization of EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent; the temperature is 26°C; and the humidity is 60%.

[0042] (3) The middle layer is made of modified polyvinyl chloride and ionic liquid additives through ionic interaction; the temperature is 50°C; and the humidity is 55%.

[0043] (4) The bottom layer is made of silane coupling agent enrichment; the temperature is 55°C; and the humidity is 65%.

[0044] (5) The gradient functionalized film is melt-extruded through a multi-layer co-extrusion technique: the mixed resin is melted at 235°C and extruded through an extruder. The extrusion line is equipped with a screen changer, a metering pump, and a die head.

[0045] (6) Embossing: Use an embossing roller to press patterns on the surface of the film in a physical mode to increase the friction of the film.

[0046] (7) Tempering: The extruded film is irradiated with high temperature infrared lamps to eliminate stress. The working temperature of the infrared lamp reaches 500℃, corresponding to a peak wavelength of 3μm.

[0047] (8) Cooling: Use rubber roller / steel roller cooling mode and natural cooling through production line to finalize the product shape.

[0048] (9) Online thickness detection: Scan the film in real time to detect thickness and adjust the process according to the thickness distribution trend.

[0049] (10) Online defect detection: Scan the film in real time to monitor appearance defects, automatically identify defects, classify them and mark their coordinates.

[0050] (11) Slitting and rewinding: Slitting and rewinding according to the set product width and length.

[0051] (12) Packaging: Pack, palletize and label the roll film packaging according to the packaging operation requirements.

[0052] Example 2: A solar encapsulation film comprising the following raw materials in parts by weight: 90 parts of EVA resin, 25 parts of modified polylactic acid, 60 parts of modified polyvinyl chloride, 1 part of crosslinking agent, 1.2 parts of auxiliary crosslinking agent, 0.5 parts of light stabilizer, 0.6 parts of stabilizer, 0.8 parts of UV absorber, 0.6 parts of silane coupling agent, 5.8 parts of nanofiller, and 1.5 parts of ionic liquid additive; The nanofiller includes perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide, and the mass ratio of perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide is 1:2:1; The ionic liquid additive is 1-butyl-3-methylimidazolium hexafluorophosphate; The modified polyvinyl chloride is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate for blending; the mass ratio of polyvinyl chloride, acrylic acid and dioctyl phthalate is 1:3:2.

[0053] The modified polylactic acid is prepared by blending ethylene-vinyl alcohol copolymer with polylactic acid and then compounding with ammonium polyphosphate. The mass ratio of ethylene-vinyl alcohol copolymer, polylactic acid and ammonium polyphosphate is 2:5:3.

[0054] The stabilizer is dipentaerythritol lanthanum rare earth metal alkoxide, which is prepared by using dipentaerythritol, maleic acid and lanthanum acetate as raw materials, and the mass ratio of dipentaerythritol, maleic acid and lanthanum acetate is 1:5:3.

[0055] The light stabilizer is bis-2,2,6,6-tetramethylpiperidinol sebacate.

[0056] The ultraviolet absorber comprises lignin and 2-hydroxy-4-n-oxybenzophenone, and the mass ratio of lignin to 2-hydroxy-4-n-oxybenzophenone is 2:3.

[0057] The crosslinking agent is tert-butyl peroxycarbonate-2-ethylhexyl ester; The auxiliary cross-linking agent includes 0.2 parts of triallyl isocyanurate, 0.2 parts of trimethylolpropane triacrylate, 0.2 parts of trimethylolpropane triacrylate, 0.4 parts of 3 (ethoxy) trimethylolpropane triacrylate, and 0.4 parts of glycerol trihydroxypropyl ether triacrylate; The silane coupling agent is γ-methacryloxypropyltrimethoxysilane; A process for preparing a solar encapsulation film comprises the following steps: (1) The mixed material is layered to prepare a gradient functionalized adhesive film, wherein the gradient functionalized adhesive film comprises a surface layer, an intermediate layer and a bottom layer, wherein the surface layer is prepared from EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent, the intermediate layer is prepared from modified polyvinyl chloride and ionic liquid additive, and the bottom layer is prepared from silane coupling agent enrichment; (2) The surface layer is prepared by copolymerization of EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent; the temperature is 26°C; and the humidity is 60%.

[0058] (3) The middle layer is made of modified polyvinyl chloride and ionic liquid additives through ionic interaction; the temperature is 50°C; and the humidity is 55%.

[0059] (4) The bottom layer is made of silane coupling agent enrichment; the temperature is 55°C; and the humidity is 65%.

[0060] (5) The gradient functionalized film is melted and extruded through a multi-layer co-extrusion technique. The mixed resin is melted at 250°C and extruded through an extruder. The extrusion line is equipped with a screen changer, a metering pump, and a die head.

[0061] (6) Embossing: Use an embossing roller to press patterns on the surface of the film in a physical mode to increase the friction of the film.

[0062] (7) Tempering: The extruded film is irradiated with high temperature infrared lamps to eliminate stress. The working temperature of the infrared lamp reaches 500℃, corresponding to a peak wavelength of 3μm.

[0063] (8) Cooling: Use rubber roller / steel roller cooling mode and natural cooling through production line to finalize the product shape.

[0064] (9) Online thickness detection: Scan the film in real time to detect thickness and adjust the process according to the thickness distribution trend.

[0065] (10) Online defect detection: Scan the film in real time to monitor appearance defects, automatically identify defects, classify them and mark their coordinates.

[0066] (11) Slitting and rewinding: Slitting and rewinding according to the set product width and length.

[0067] (12) Packaging: Pack, palletize and label the roll film packaging according to the packaging operation requirements.

[0068] Example 3: A solar encapsulation film comprising the following raw materials in parts by weight: 100 parts of EVA resin, 30 parts of modified polylactic acid, 80 parts of modified polyvinyl chloride, 2 parts of crosslinking agent, 2 parts of auxiliary crosslinking agent, 1 part of light stabilizer, 1.5 parts of stabilizer, 1.5 parts of UV absorber, 1.2 parts of silane coupling agent, 8.5 parts of nanofiller, 2.5 parts of ionic liquid additive; The nanofiller includes perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide, and the mass ratio of perovskite quantum dots, nano-calcium carbonate and nano-titanium dioxide is 1:3:2; The ionic liquid additive is 1-butyl-3-methylimidazolium hexafluorophosphate; The nano filler comprises nano calcium carbonate and nano titanium dioxide, and the mass ratio of the nano calcium carbonate to the nano titanium dioxide is 3:1.

[0069] The modified polyvinyl chloride is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate for blending; the mass ratio of polyvinyl chloride, acrylic acid and dioctyl phthalate is 1:5:3.

[0070] The modified polylactic acid is prepared by blending ethylene-vinyl alcohol copolymer with polylactic acid and then compounding with ammonium polyphosphate. The mass ratio of ethylene-vinyl alcohol copolymer, polylactic acid and ammonium polyphosphate is 2:8:5.

[0071] The stabilizer is dipentaerythritol lanthanum rare earth metal alkoxide, which is prepared by using dipentaerythritol, maleic acid and lanthanum acetate as raw materials, and the mass ratio of dipentaerythritol, maleic acid and lanthanum acetate is 2:5:3.

[0072] The light stabilizer is bis-2,2,6,6-tetramethylpiperidinol sebacate.

[0073] The ultraviolet absorber comprises lignin and 2-hydroxy-4-n-oxybenzophenone, and the mass ratio of lignin to 2-hydroxy-4-n-oxybenzophenone is 2:5.

[0074] The crosslinking agent is tert-butyl peroxycarbonate-2-ethylhexyl ester; The auxiliary crosslinking agent includes 0.3 parts of triallyl isocyanurate, 0.3 parts of trimethylolpropane triacrylate, 0.3 parts of trimethylolpropane triacrylate, 0.5 parts of 3 (ethoxy) trimethylolpropane triacrylate, and 0.5 parts of glycerol trihydroxypropyl ether triacrylate; The silane coupling agent is γ-methacryloxypropyltrimethoxysilane; A process for preparing a solar encapsulation film comprises the following steps: (1) The mixed material is layered to prepare a gradient functionalized adhesive film, wherein the gradient functionalized adhesive film comprises a surface layer, an intermediate layer and a bottom layer, wherein the surface layer is prepared from EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent, the intermediate layer is prepared from modified polyvinyl chloride and ionic liquid additive, and the bottom layer is prepared from silane coupling agent enrichment; (2) The surface layer is prepared by copolymerization of EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent; the temperature is 26°C; and the humidity is 60%.

[0075] (3) The middle layer is made of modified polyvinyl chloride and ionic liquid additives through ionic interaction; the temperature is 50°C; and the humidity is 55%.

[0076] (4) The bottom layer is made of silane coupling agent enrichment; the temperature is 55°C; and the humidity is 65%.

[0077] (5) The gradient functionalized film is melt-extruded through a multi-layer co-extrusion technique: the mixed resin is melted at 235°C and extruded through an extruder. The extrusion line is equipped with a screen changer, a metering pump, and a die head.

[0078] (6) Embossing: Use an embossing roller to press patterns on the surface of the film in a physical mode to increase the friction of the film.

[0079] (7) Tempering: The extruded film is irradiated with high temperature infrared lamps to eliminate stress. The working temperature of the infrared lamp reaches 500℃, corresponding to a peak wavelength of 3μm.

[0080] (8) Cooling: Use rubber roller / steel roller cooling mode and natural cooling through production line to finalize the product shape.

[0081] (9) Online thickness detection: Scan the film in real time to detect thickness and adjust the process according to the thickness distribution trend.

[0082] (10) Online defect detection: Scan the film in real time to monitor appearance defects, automatically identify defects, classify them and mark their coordinates.

[0083] (11) Slitting and rewinding: Slitting and rewinding according to the set product width and length.

[0084] (12) Packaging: Pack, palletize and label the roll film packaging according to the packaging operation requirements.

[0085] Comparative Example 1: The difference from Example 1 is that no nanofiller is added.

[0086] Comparative Example 2: The difference from Example 1 is that no modified polyvinyl chloride is added.

[0087] Comparative Example 3: The difference from Example 1 is that no stabilizer is added.

[0088] Comparative Example 4: The difference from Example 1 is that no ultraviolet absorber is added.

[0089] Table 1 Performance test results

[0090] As shown in Table 1, the solar encapsulation film prepared in Example 1 has relatively good light transmittance, peel strength with glass, crosslinking degree, and PID power attenuation. This indicates that the addition of multiple additives, such as modified polyvinyl chloride, crosslinking agent, co-crosslinking agent, and light stabilizer, allows the additives to work together to give the prepared solar encapsulation film high light transmittance, good adhesion, weather resistance, UV resistance, and aging resistance.

[0091] Comparing the test results of Comparative Example 1 and Example 1, the comparative example 1 does not add nanofillers, and the peel strength with glass is lower, which shows that the nanofillers added in Example 1, nano calcium carbonate and nano titanium dioxide in the EVA film work synergistically, and the two form a bonding network with the silane coupling agent, which simultaneously improves the strength and weather resistance, and plays an important role in mechanical properties, thermal stability, UV resistance and conductivity.

[0092] Comparing the test results of Comparative Example 2 with those of Example 1, which lacks modified PVC, reveals significant differences in peel strength and crosslinking degree with glass. This demonstrates that the addition of modified PVC in Example 1, combined with the addition of modified PVC to the EVA resin, enhances EVA toughness through multi-dimensional synergistic optimization. The resulting graft copolymer forms a network structure, enhancing the material's tensile strength and effectively resisting mechanical stress during component lamination.

[0093] Comparing the test results of Comparative Example 3 with those of Example 1, the PID power attenuation rate was greater in Comparative Example 3, which did not include a stabilizer. This indicates that the addition of a lanthanum dipentaerythritol rare earth metal alkoxide stabilizer reduces free radicals generated by thermal decomposition, captures and neutralizes acidic byproducts such as acetic acid produced by acetic acid removal, and inhibits autocatalytic degradation. Furthermore, the rare earth complex-modified EVA exhibits a synergistic effect with the light stabilizer, delaying yellowing and reducing transmittance attenuation in wet heat and UV tests.

[0094] Comparing the test results of Comparative Example 4 with those of Example 1, the transmittance of Comparative Example 4, which lacks a UV absorber, is lower. This demonstrates that the UV absorbers lignin and 2-hydroxy-4-(n-hydroxybenzophenone) effectively absorb UV light with a wavelength of 270-330 nm, thereby reducing color change, delaying yellowing, and loss of physical properties. Furthermore, they exhibit good compatibility and can synergize with the EVA resin and crosslinker to improve the weather resistance and long-term stability of the EVA material.

[0095] The foregoing description is merely an exemplary embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A solar encapsulation film, characterized in that: The invention comprises the following raw materials in parts by weight: 80-100 parts of EVA resin, 20-30 parts of modified polylactic acid, 40-80 parts of modified polyvinyl chloride, 0.5-2 parts of a crosslinking agent, 0.5-2 parts of a co-crosslinking agent, 0.05-1 parts of a light stabilizer, 0.05-1.5 parts of a stabilizer, 0.5-1.5 parts of an ultraviolet absorber, 0.3-1.2 parts of a silane coupling agent, 2.5-8.5 parts of a nanofiller, and 0.5-2.5 parts of an ionic liquid additive; the nanofiller comprises perovskite quantum dots, nano-calcium carbonate, and nano-titanium dioxide, and the mass ratio of the perovskite quantum dots, nano-calcium carbonate, and nano-titanium dioxide is 1:1-3:1-2; and the ionic liquid additive is 1-butyl-3-methylimidazole hexafluorophosphate.

2. The solar encapsulation film according to claim 1, characterized in that: The modified polyvinyl chloride is prepared by grafting acrylic acid onto polyvinyl chloride and then adding dioctyl phthalate for blending. The mass ratio of the polyvinyl chloride, acrylic acid and dioctyl phthalate is 1:1-5:2-3.

3. The solar encapsulation film according to claim 2, characterized in that: The modified polylactic acid is prepared by blending ethylene-vinyl alcohol copolymer with polylactic acid and then compounding with ammonium polyphosphate. The mass ratio of the ethylene-vinyl alcohol copolymer, polylactic acid and ammonium polyphosphate is 1-2:5-8:3-5.

4. The solar encapsulation film according to claim 1, characterized in that: The stabilizer is a lanthanum dipentaerythritol rare earth metal alkoxide, which is prepared from dipentaerythritol, maleic acid and lanthanum acetate as raw materials, and the mass ratio of the dipentaerythritol, maleic acid and lanthanum acetate is 1-2:3-5:1-3.

5. The solar encapsulation film according to claim 1, characterized in that: The ultraviolet absorber comprises lignin and 2-hydroxy-4-n-oxybenzophenone, and the mass ratio of the lignin to the 2-hydroxy-4-n-oxybenzophenone is 1-2:3-5.

6. The solar encapsulation film according to claim 1, characterized in that: The cross-linking agent is one or more of tert-butyl peroxycarbonate-2-ethylhexyl ester, tert-butyl peroxycarbonate-2-ethylhexyl ester, dicumyl peroxide, and triallyl isocyanurate.

7. The solar encapsulation film according to claim 1, characterized in that: The auxiliary cross-linking agent is one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane triacrylate, 3 (ethoxy) trimethylolpropane triacrylate, and glycerol trihydroxypropyl ether triacrylate.

8. The solar encapsulation film according to claim 1, characterized in that: The silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane, 3-(methacryloxy)propyltrimethoxysilane and vinyltrimethoxysilane.

9. The process for preparing the solar encapsulation film according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) The mixed material is layered to prepare a gradient functionalized adhesive film, wherein the gradient functionalized adhesive film comprises a surface layer, an intermediate layer and a bottom layer, wherein the surface layer is prepared from EVA resin, modified polylactic acid, nanofiller, light stabilizer, stabilizer, ultraviolet absorber, co-crosslinking agent and crosslinking agent, the intermediate layer is prepared from modified polyvinyl chloride and ionic liquid additive, and the bottom layer is prepared from silane coupling agent enrichment; (2) The gradient functionalized film in (1) is melt-extruded, embossed, tempered, and cooled by a multi-layer co-extrusion technology, and a pattern is pressed on the surface of the film by an embossing roller in a physical mode. During tempering, the extruded film is irradiated with high temperature by an infrared lamp; (3) After online thickness detection, online defect detection, slitting and winding, the solar encapsulation film is obtained.

10. A solar cell module, characterized in that: The solar cell assembly comprises the solar encapsulation film according to any one of claims 1 to 8.

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