Anti-migration black pigment, high-reflection black packaging adhesive film and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic materials, in particular to an anti-migration black pigment, a high-reflection black packaging adhesive film and a photovoltaic module. The anti-migration black pigment has a structural general formula as shown in a formula I, wherein R1 is at least one of R1, R2, R3, R4, R5, R6 and R7. The anti-migration black pigment disclosed by the invention is blue-phase black, and has excellent damp-heat resistance and migration resistance; when being used for a black packaging adhesive film, the black packaging adhesive film can be well matched with the color of a battery piece without adding other auxiliary pigments for color matching; and in a high-temperature and high-humidity environment, the color difference change value (delta E) of the color of the adhesive film is remarkably reduced, and the requirement that delta E is less than or equal to 2 in long-term use of the photovoltaic adhesive film is completely met.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic materials technology, and in particular to an anti-migration black pigment, a high-reflectivity black encapsulating film, and a photovoltaic module. Background Technology

[0002] In high-reflectivity black encapsulating films and black components, the fundamental driving force for pigment migration stems from the difference in concentration gradient. The pigment concentration is high in the black layer and low in the white layer and the transparent film on the front of the component. According to the second law of thermodynamics, pigment molecules diffuse from high-concentration areas to low-concentration areas. Currently, the black pigment widely used in high-reflectivity black encapsulating films is perylene black pigment, whose core structure is perylene tetracarboxylate diimide. Traditional perylene black pigment has a large π-conjugated planar structure. This planar structure promotes close molecular stacking and forms a stable lattice structure through π-π stacking interactions, resulting in an ordered arrangement of pigment particles at room temperature. However, in high-temperature and high-humidity environments, molecular thermal motion intensifies, and the binding energy of π-π stacking is insufficient to resist thermal motion, leading to lattice structure disruption and allowing molecules to migrate. Simultaneously, under high humidity conditions, hydrogen bonds form between oxygen atoms in water molecules and carbon atoms of the carbonyl group on the perylene black pigment imide ring. This competitive interaction further weakens the original π-π stacking effect and exacerbates the destruction of the crystal structure. Therefore, perylene black pigments in high-reflectivity black encapsulating films are more prone to diffusion and migration under high temperature and high humidity conditions.

[0003] Furthermore, existing perylene black pigments are all green-phase black pigments. To make them closer to the color of the solar cells, additional red, yellow, or blue pigments need to be added for auxiliary color matching. However, the film obtained by this color matching process will change color after dry heat or UV aging, further increasing the color difference with the solar cells; and the white surface will also show a slightly reddish tint.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-migration black pigment, a high-reflectivity black encapsulating film, and a photovoltaic module. The anti-migration black pigment of this invention is a bluish-black color and has excellent resistance to damp heat and anti-migration properties. When used in a black encapsulating film, no other auxiliary pigments are needed for color matching to achieve good color matching with the solar cell. Furthermore, under high temperature and high humidity conditions, the color difference change value (ΔE) of the film is significantly reduced, fully meeting the requirement of ΔE≤2 for long-term use of photovoltaic encapsulating films.

[0006] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides an anti-migration black pigment having a general structural formula as shown in Formula I: ; Where R1 is , , , , At least one of them.

[0007] A second aspect of the present invention provides a high-reflectivity black encapsulating film, comprising a black layer and a white layer stacked together; the black layer includes an anti-migration black pigment provided in the first aspect of the present invention.

[0008] In a specific embodiment of the present invention, the black layer comprises a matrix resin and the anti-migration black pigment, wherein the amount of the anti-migration black pigment is 0.1% to 2% of the mass of the matrix resin.

[0009] In a specific embodiment of the present invention, a silane coupling agent is used to modify the anti-migration black pigment. Further, the mass ratio of the silane coupling agent to the anti-migration black pigment is (0.01–0.1):1.

[0010] In a specific embodiment of the present invention, the black layer further includes at least one selected from crosslinking agent, co-crosslinking agent, silane coupling agent, antioxidant, and light stabilizer. Further, the amounts of the crosslinking agent, co-crosslinking agent, silane coupling agent, antioxidant, and light stabilizer are 0.5%–1.5%, 0.5%–1.5%, 0.1%–1%, 0.1%–0.5%, and 0.1%–0.5% of the mass of the matrix resin, respectively.

[0011] In a specific embodiment of the present invention, the white layer comprises a matrix resin, a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, a light stabilizer, and white pigment powder.

[0012] In a specific embodiment of the present invention, the amounts of the crosslinking agent, co-crosslinking agent, silane coupling agent, antioxidant, light stabilizer and white pigment powder in the white layer are 0.5% to 1.5%, 0.5% to 1.5%, 0.1% to 1%, 0.1% to 0.5%, 0.1% to 0.5% and 5% to 20% of the mass of the matrix resin, respectively.

[0013] In a specific embodiment of the present invention, the white pigment powder includes at least one of titanium dioxide, silicon dioxide, hollow glass microspheres, zinc oxide, zinc sulfide, and barium sulfate.

[0014] In a specific embodiment of the present invention, the matrix resin in the black layer and the matrix resin in the white layer each independently comprise EVA resin. Further, the EVA resin has a VA content of not less than 25 wt% and a melt index of 5–25 g / 10 min at 190°C / 2.16 kg.

[0015] In a specific embodiment of the present invention, the thickness ratio of the black layer to the white layer is (0.2~1.5):1. Further, the thickness of the high-reflectivity black encapsulating film is 0.4~1 mm.

[0016] A third aspect of the present invention provides a photovoltaic module, including a high-reflectivity black encapsulating film according to the second aspect of the present invention.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention modifies the pigment structure, changes the planar structure of perylene black, increases the π-π stacking distance between molecules, effectively weakens the π-π stacking effect, and avoids pigment aggregation; at the same time, the introduced steric hindrance groups construct a "cage-like" three-dimensional network, which can bind the thermal motion of molecules in a humid and hot environment; in a high temperature and high humidity environment, the color difference change value ΔE of the film can be reduced to 0.5 to 1.5, which fully meets the requirement of ΔE≤2 in the long-term use of photovoltaic films; (2) The anti-migration black pigment of the present invention is blue-phase black. When used in black encapsulation film, it can match the front color of TOPCon battery without adding other auxiliary pigments to adjust the color, effectively avoiding the situation of increased color difference in the front color change in the existing pigment system; in addition, the use of a single pigment does not require masterbatch preparation, and can be directly added and mixed with other components, simplifying the preparation process of the encapsulation film. (3) The anti-migration black pigment of the present invention has good compatibility with the matrix resin and can be well dispersed in the film to ensure the appearance of the film product; and the anti-migration black pigment of the present invention can effectively absorb ultraviolet rays (UV-B, UV-A) and reduce the damage of ultraviolet rays to the molecular structure. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 The images show a comparison of the discoloration of the front area of ​​the component made from the adhesive film of Embodiment 1 of the present invention before and after dry heat aging; where (a) is an image of the front area of ​​the initial component; and (b) is an image of the front area of ​​the component after aging. Figure 2 Comparison of the discoloration of the front area of ​​the component made from the film of Comparative Example 1 before and after dry heat aging; where (a) is the initial image of the front area of ​​the component; and (b) is the image of the front area of ​​the component after aging. Figure 3 The images show a comparison of the discoloration of the back side of the component made from the adhesive film of Embodiment 1 of the present invention before and after dry heat aging; where (a) is an image of the back side of the component in its initial state; and (b) is an image of the back side of the component after aging. Figure 4 Comparison of the discoloration of the back side of the module made from the film of Comparative Example 1 before and after dry heat aging; where (a) is the initial image of the back side of the module; and (b) is the image of the back side of the module after aging. Figure 5 The images show a comparison of the discoloration of the back side of the component made from the adhesive film of Embodiment 1 of the present invention before and after humid heat aging; where (a) is an image of the back side of the component in its initial state; and (b) is an image of the back side of the component after aging. Figure 6 Comparison of the discoloration of the back side of the module made from the film of Comparative Example 1 before and after humid heat aging; where (a) is the initial image of the back side of the module; and (b) is the image of the back side of the module after aging. Figure 7 The images show a comparison of the discoloration of the back side of the component made from the adhesive film of Embodiment 1 of the present invention before and after ultraviolet aging; where (a) is an image of the back side of the component in its initial state; and (b) is an image of the back side of the component after aging. Figure 8 The images show a comparison of the discoloration of the back side of the module made from the film of Comparative Example 1 before and after UV aging; where (a) is an image of the back side of the module in its initial state; and (b) is an image of the back side of the module after aging. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0021] The first aspect of this invention provides an anti-migration black pigment having the general structural formula shown in Formula I: ; Where R1 is , , , , At least one of them. The * in R1 above refers to the site where R1 is connected to the structure shown in Formula I.

[0022] This invention modifies the pigment structure, altering the planar structure of perylene black by introducing ultra-large sterically hindered side chains on both sides. This breaks the planar conjugated structure, resulting in a distorted three-dimensional configuration (the phenyl groups on both sides are not coplanar with the core structure). This increases the π-π stacking distance between molecules, effectively weakening the π-π stacking effect. Simultaneously, the introduced sterically hindered groups construct a "cage-like" three-dimensional network, which can confine the thermal motion of molecules in humid and hot environments. Under high temperature and high humidity conditions, the thermal motion of pigment molecules cannot overcome the steric hindrance, reducing the color difference change value ΔE of the film to 0.5–1.5 (ΔE < 2 is imperceptible to the naked eye), fully meeting the requirement of ΔE ≤ 2 for long-term use of photovoltaic films.

[0023] Furthermore, the anti-migration black pigment of the present invention is a blue-phase black. When used in black encapsulation films, it can match the front color of TOPCon batteries without the need to add other auxiliary pigments for color matching, effectively avoiding the situation where the front color changes and color difference increases in existing pigment systems. Moreover, the use of a single pigment eliminates the need for masterbatch preparation and can be directly added and mixed with other components, simplifying the film preparation process.

[0024] Furthermore, the anti-migration black pigment of the present invention has good compatibility with the matrix resin and can be well dispersed in the film, ensuring the appearance of the film product; and the anti-migration black pigment of the present invention can effectively absorb ultraviolet rays (UV-B, UV-A), reduce the damage of ultraviolet rays to the molecular structure, and ensure that it does not change color in the long-term ultraviolet aging environment.

[0025] In some embodiments, the structural formulas of the anti-migration black pigments may be exemplarily as follows: (Ⅰ1); (Ⅰ2); (Ⅰ3); (Ⅰ4); (Ⅰ5).

[0026] The preparation method of the anti-migration black pigment of the present invention is not limited. The present invention provides an optional preparation method, specifically comprising: 3,4,9,10-perylenetetracarboxylic dianhydride and... In an organic solvent, react at 160–200 °C for 4–6 h.

[0027] In some embodiments, 3,4,9,10-perylenetetracarboxylic dianhydride and The molar ratio is 1:(2-3).

[0028] In some embodiments, the organic solvent includes at least one of N-methylpyrrolidone and imidazole.

[0029] In some embodiments, after the reaction is completed, the reacted material is cooled to 80-90°C; then it is poured into 5-20 times its volume of an ice-water-methanol mixed solution (water to methanol volume ratio of 1:1), the precipitate is collected by filtration and then acid-washed, water-washed, and dried to obtain an anti-migration black pigment.

[0030] Used for preparing the anti-migration black pigment shown in Formula I It may include: 4-(2-phenylpropane-2-yl)aniline, phenyl-4-aminobenzoate, and methyl 4'-aminobiphenyl-4-carboxylate.

[0031] A second aspect of the present invention provides a high-reflectivity black encapsulating film, comprising a black layer and a white layer stacked together; the black layer includes an anti-migration black pigment provided in the first aspect of the present invention.

[0032] In some embodiments, the black layer comprises a matrix resin and an anti-migration black pigment, wherein the amount of the anti-migration black pigment is 0.1% to 2% of the mass of the matrix resin, specifically 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, or any combination thereof.

[0033] In some embodiments, a silane coupling agent is used to modify the anti-migration black pigment. Further, the mass ratio of the silane coupling agent to the anti-migration black pigment is (0.01–0.1):1, specifically within the range of 0.01:1, 0.03:1, 0.05:1, 0.08:1, 0.1:1, or any combination thereof.

[0034] In some embodiments, the silane coupling agent includes, but is not limited to, at least one of 3-glycidyl etheroxypropylmethyldiethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-ureapropyltrialkoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0035] In some embodiments, the modification process includes: dispersing an anti-migration black pigment in ethanol, then adding a silane coupling agent in proportion, heating to 55-65°C and stirring for 1-3 hours; then ball milling, and then removing the ethanol.

[0036] In some embodiments, the mass ratio of the anti-migration black pigment to ethanol is 1:(2-4).

[0037] In some embodiments, the D90 particle size of the modified anti-migration black pigment is 80–120 nm.

[0038] In some embodiments, the black layer further includes at least one of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, and a light stabilizer.

[0039] In some embodiments, the amount of crosslinking agent in the black layer is 0.5% to 1.5% of the mass of the matrix resin, specifically 0.5%, 0.8%, 1%, 1.2%, 1.5%, or any combination thereof.

[0040] In some embodiments, the crosslinking agent includes peroxide-based crosslinking agents, including, but not limited to, at least one of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butyl peroxide, and tert-amyl peroxide.

[0041] In some embodiments, the amount of the crosslinking agent in the black layer is 0.5% to 1.5% of the mass of the matrix resin, specifically 0.5%, 0.8%, 1%, 1.2%, 1.5%, or any combination thereof.

[0042] In some embodiments, the co-crosslinking agent includes at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and diallyl phthalate.

[0043] In some embodiments, the amount of silane coupling agent in the black layer is 0.1% to 1% of the mass of the matrix resin, specifically 0.1%, 0.3%, 0.5%, 0.8%, 1%, or any combination thereof.

[0044] In some embodiments, the silane coupling agent includes at least one selected from 3-glycidyl etheroxypropylmethyldiethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-ureapropyltrialkoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0045] In some embodiments, the amount of antioxidant in the black layer is 0.1% to 0.5% of the mass of the matrix resin, specifically 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any combination thereof.

[0046] In some embodiments, the antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenol, dioctadecyl thiodipropionate, and phosphite.

[0047] In some embodiments, the amount of light stabilizer in the black layer is 0.1% to 0.5% of the mass of the matrix resin, specifically 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any combination thereof.

[0048] In some embodiments, the light stabilizer includes at least one of phenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole and resorcinol monobenzoate.

[0049] In some embodiments, the white layer includes a matrix resin, a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, a light stabilizer, and white pigment powder.

[0050] In some embodiments, the amount of crosslinking agent in the white layer is 0.5% to 1.5% of the mass of the matrix resin, specifically 0.5%, 0.8%, 1%, 1.2%, 1.5%, or any combination thereof. The specific types of crosslinking agents are the same as those in the black layer and will not be repeated here.

[0051] In some embodiments, the amount of the co-crosslinking agent in the white layer is 0.5% to 1.5% of the mass of the matrix resin, specifically 0.5%, 0.8%, 1%, 1.2%, 1.5%, or any combination thereof. The specific types of co-crosslinking agents are the same as those in the black layer and will not be repeated here.

[0052] In some embodiments, the amount of silane coupling agent in the white layer is 0.1% to 1% of the matrix resin mass, specifically 0.1%, 0.3%, 0.5%, 0.8%, 1%, or any combination thereof. The specific types of silane coupling agents are the same as those in the black layer and will not be repeated here.

[0053] In some embodiments, the amount of antioxidant in the white layer is 0.1% to 0.5% of the matrix resin mass, specifically 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any combination thereof. The specific types of antioxidants are the same as those in the black layer and will not be repeated here.

[0054] In some embodiments, the amount of light stabilizer in the white layer is 0.1% to 0.5% of the mass of the matrix resin, specifically within the range of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any combination thereof. The specific types of light stabilizers are the same as those in the black layer and will not be repeated here.

[0055] In some embodiments, the amount of white pigment powder in the white layer is 5% to 20% of the mass of the matrix resin, specifically 5%, 8%, 10%, 12%, 15%, 18%, 20%, or any combination thereof.

[0056] In some embodiments, the white pigment powder includes at least one of titanium dioxide, silicon dioxide, hollow glass microspheres, zinc oxide, zinc sulfide, and barium sulfate, preferably rutile nano-sized titanium dioxide.

[0057] In some embodiments, the matrix resin in the black layer and the matrix resin in the white layer each independently comprise EVA resin. Further, the EVA resin contains not less than 25 wt%, preferably 26 wt% to 30 wt%; and has a melt index of 5 to 25 g / 10 min at 190°C / 2.16 kg, preferably 5 to 8 g / 10 min.

[0058] In some embodiments, the thickness ratio of the black layer to the white layer is (0.2–1.5):1, specifically within the range of 0.2:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, or any combination thereof. Further, the thickness of the high-reflectivity black encapsulating film is 0.4–1 mm, specifically within the range of 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, or any combination thereof.

[0059] The present invention also provides an optional method for preparing a high-reflectivity black encapsulating film, comprising the following steps: preparing the ingredients according to the composition of the black layer and the white layer of the high-reflectivity black encapsulating film, performing extrusion casting, and irradiating the black layer to obtain the high-reflectivity black encapsulating film.

[0060] In some embodiments, the extrusion casting temperature is 60–90°C, preferably 80–90°C.

[0061] In some embodiments, during the irradiation treatment, the irradiation voltage is 300–500 kV, preferably 500 kV; the irradiation dose is 20–50 mA, preferably 30–40 mA; and the irradiation linear velocity is 10–35 m / min, preferably 20–30 m / min.

[0062] A third aspect of the present invention provides a photovoltaic module, including a high-reflectivity black encapsulating film according to the second aspect of the present invention.

[0063] In some embodiments, the photovoltaic module includes a front glass panel, a high-transparency encapsulating film, solar cells, a high-reflectivity black encapsulating film, and a back glass panel, all stacked together.

[0064] In some embodiments, the high-transmittance encapsulating film has a transmittance of ≥75% in the 290–380 nm range and a transmittance of ≥90.6% in the 380–1100 nm range, including but not limited to Lushan's EV1050G2 or S102.

[0065] In some embodiments, the photovoltaic module is fabricated by stacking the above-described structures and then laminating them. Further, during the lamination process, the temperature of the heating plate can be 140–152°C, and the vacuuming time can be 5–6 minutes; then, several pressurization cycles are performed. In actual operation, the temperature of the heating plate, the vacuuming time, and the pressurization parameters can be adjusted conventionally to obtain the corresponding photovoltaic module. The EVA resin used in the following embodiments of the present invention may be of the type Sirbon UE2806, but is not limited thereto.

[0066] Example 1 This embodiment provides a high-reflectivity black encapsulating film, comprising a black layer and a white layer stacked together. The thickness of the high-reflectivity black encapsulating film is 0.6 mm, and the thickness ratio of the black layer to the white layer is 1:1.

[0067] The white layer, by weight, comprises the following raw materials: 100 parts of EVA resin E280PV, 1 part of crosslinking agent 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 0.5 parts of co-crosslinking agent trimethylolpropane triacrylate, 0.4 parts of silane coupling agent 3-glycidyl etheroxypropylmethyldiethoxysilane, 0.2 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 0.2 parts of light stabilizer phenyl salicylate, and 20 parts of rutile nano-sized titanium dioxide.

[0068] The black layer, by weight, comprises the following raw materials: 100 parts of EVA resin E280PV, 1 part of crosslinking agent 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 0.5 parts of co-crosslinking agent trimethylolpropane triacrylate, 0.4 parts of silane coupling agent 3-glycidyl etheroxypropylmethyldiethoxysilane, 0.2 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 0.2 parts of light stabilizer phenyl salicylate, and 1.5 parts of black pigment powder.

[0069] The preparation of the black pigment powder includes: taking a certain mass of the compound shown in Formula I1, adding it to ethanol, with a mass ratio of the compound shown in Formula I1 to ethanol of 1:3, and ultrasonically dispersing at 200W for 10 min to obtain a uniform dispersion; adding silane coupling agent KH550 (5wt% of the compound shown in Formula I1) to the dispersion, and then heating to 60℃ and stirring for 2 h to obtain a black powder dispersion. The black powder dispersion is placed in a ball mill, and zirconia balls are added at a mass ratio of black powder dispersion to zirconia balls of 1:5, and ball milled at 2500 rpm for 1 h. Then, the ball-milled dispersion is poured into a rotary evaporator, and the ethanol is removed by vacuum distillation to obtain black pigment powder with a D90 particle size of 100 nm.

[0070] (Ⅰ1) The preparation method of the compound shown in Formula I1 is as follows: In a 100 mL four-necked flask, 30 mL of imidazole and 10 mL of N-methylpyrrolidone were added. The mixture was heated to 120 °C with stirring under a nitrogen atmosphere. Perylene tetracarboxylic dianhydride (3.92 g) was added, and the temperature was further increased to 150 °C with stirring for 30 min to obtain the first solution. 5.28 g of 4-(2-phenylpropane-2-yl)aniline was dissolved in 10 mL of N-methylpyrrolidone to obtain the second solution. The first solution was cooled to 130 °C, and the second solution was slowly added dropwise. After the addition was complete, the temperature was increased to 180 °C, and the reaction was stirred for 6 h. After the reaction was completed, the temperature was lowered to 80℃, and the reaction solution was poured into 300 mL of ice-cold methanol-water mixed solution (water to methanol volume ratio of 1:1, 0-4℃). The mixture was stirred vigorously, and the product precipitated. The product was filtered to obtain a dark red filter cake. The filter cake was washed successively with 5 wt% hydrochloric acid solution (100 mL each time, twice), deionized water (100 mL each time, three times), and ethanol (50 mL, once). Then, it was dried under vacuum at 60℃ for 12 h to obtain a black solid powder with a yield of 72.38%.

[0071] Structural characterization using NMR and mass spectrometry confirmed it to be the target product. Specifically, the calculated value C for MALDI-TOF mass spectrometry (MS / Z) was [value missing]. 54 H 38 N₂O₄, 778.28; measured value 778.91 [M+H] + ; 1 H NMR (DMSO-d6, 400 MHz)δ: 8.62 (d,4H, J=8.0), 8.48 (d, 4H, J=8.0), 7.45 (m, 8H, J=7.2), 7.30 (t, 4H, J=7.2),7.25 (m, 12H, J=7.6), 7.10 (d, 6H, J=7.6);13 C NMR (DMSO-d6, 125 MHz, 100℃) δ(ppm): 163.2 (C=O), 146.8 (Cq), 140.5 (Cq), 131.7 (Cq), 129.9 (CH), 72.5(Cq).

[0072] The preparation method of the high-reflectivity black encapsulating film in this embodiment includes the following steps: according to the composition of the black layer and the white layer of the high-reflectivity black encapsulating film, the film is extruded and stretched at 80°C through a co-extrusion die, and the black layer is irradiated under the conditions of 500KV voltage, 30mA irradiation dose and 25m / min irradiation linear velocity, and then wound up to obtain the high-reflectivity black encapsulating film.

[0073] Example 2 This embodiment refers to the high-reflectivity black encapsulating film and its preparation method in Example 1, except that in the preparation of the black pigment powder, an equal weight of the compound represented by Formula I4 is used to replace the compound represented by Formula I1 in Example 1.

[0074] (Ⅰ4) The preparation method of the compound shown in Formula I4 is as follows: In a 100 mL four-necked flask, 30 mL of imidazole and 10 mL of N-methylpyrrolidone were added. The mixture was heated to 120 °C with stirring under a nitrogen atmosphere. Perylene tetracarboxylic dianhydride (3.92 g) was added, and the temperature was further increased to 150 °C with stirring for 30 min to obtain the first solution. 4.54 g of phenyl 4-aminobenzoate was dissolved in 10 mL of N-methylpyrrolidone to obtain the second solution. The first solution was cooled to 130 °C, and the second solution was slowly added dropwise. After the addition was complete, the temperature was increased to 180 °C, and the reaction was stirred for 6 h. After the reaction was completed, the temperature was lowered to 80℃, and the reaction solution was poured into 300 mL of ice-cold methanol-water mixture (water to methanol volume ratio of 1:1, 0-4℃). The mixture was stirred vigorously, and the product precipitated. The product was filtered to obtain a blackish-red filter cake. The filter cake was washed successively with 5wt% hydrochloric acid solution (100 mL each time, twice), deionized water (100 mL each time, three times), and ethanol (50 mL, once). Then, it was dried under vacuum at 60℃ for 12 h to obtain a black solid powder with a yield of 68.22%.

[0075] Structural characterization using NMR and mass spectrometry confirmed it to be the target product. Specifically, the calculated value C for MALDI-TOF (m / z) mass spectrometry was obtained. 50 H 26 N₂O₈, 782.17; measured value 782.96 [M+H] + ; 1H NMR (DMSO-d6, 400 MHz) δ: 8.85 (d,4H, J=8.2), 8.62 (d, 4H, J=8.2), 8.20 (d, 4H, J=8.4), 7.55 (t, 4H, J=7.4),7.25 (d, 4H, J=8.4), 7.00 (t, 2H, J=7.2), 6.80 (d, 4H, J=8.0); 13 C NMR (DMSO-d6, 125 MHz, 100℃) δ (ppm): 164.5 (C=O), 162.8 (C=O), 151.5 (Cq), 141.2(Cq), 132.7 (Cq), 129.8 (CH), 128.5 (CH), 127.3 (CH), 125.6 (Cq), 122.3 (CH).

[0076] Example 3 This embodiment refers to the high-reflectivity black encapsulating film and its preparation method in Example 1, except that in the preparation of the black pigment powder, the compound represented by Formula I2 of equal weight is used instead of the compound represented by Formula I1 in Example 1.

[0077] (Ⅰ2) The preparation method of the compound shown in Formula I2 is as follows: In a 100 mL four-necked flask, 30 mL of imidazole and 10 mL of N-methylpyrrolidone were added. The mixture was heated to 120 °C with stirring under a nitrogen atmosphere. Perylene tetracarboxylic anhydride (3.92 g) was added, and the temperature was further increased to 150 °C with stirring for 30 min to obtain the first solution. 5.67 g of methyl 4'-aminobiphenyl-4-carboxylate was dissolved in 10 mL of N-methylpyrrolidone to obtain the second solution. The first solution was cooled to 130 °C, and the second solution was slowly added dropwise. After the addition was complete, the temperature was increased to 200 °C, and the reaction was stirred for 6 h. After the reaction was completed, the temperature was lowered to 80℃, and the reaction solution was poured into 300 mL of ice-cold methanol-water mixture (water to methanol volume ratio of 1:1, 0-4℃). The mixture was stirred vigorously, and the product precipitated. The product was filtered to obtain a blackish-red filter cake. The filter cake was washed successively with 5wt% hydrochloric acid solution (100 mL each time, twice), deionized water (100 mL each time, three times), and ethanol (50 mL, once). Then, it was dried under vacuum at 60℃ for 12 h to obtain a black solid powder with a yield of 78.92%.

[0078] Structural characterization using NMR and mass spectrometry confirmed it to be the target product. Specifically, the calculated value C for MALDI-TOF (m / z) mass spectrometry was obtained. 52 H 30N₂O₈, 810.20; Test value 810.82 [M+H] + ; 1 H NMR (DMSO-d6, 400 MHz) δ: 8.88(d, 4H, J=8.1), 8.65 (d, 4H, J=8.1), 8.15 (d, 4H, J=8.5), 7.60 (d, 4H, J=8.5), 7.45 (t, 4H, J=7.3), 7.30 (d, 4H, J=7.6), 3.90 (s, 6H); 13 C NMR (DMSO-d6,125 MHz, 100℃) δ(ppm): 164.5 (C=O), 163.0 (C=O), 152.0 (Cq), 141.5 (Cq), 139.0 (Cq), 133.0 (Cq), 129.5 (CH), 128.0 (CH), 127.5 (CH), 125.8 (Cq), 52.5 (CH3).

[0079] Comparative Example 1 Comparative Example 1 refers to the high-reflectivity black encapsulating film and its preparation method as described in Example 1, except that in the preparation of the black pigment powder, an equal weight of the compound represented by Formula II (pigment black 32) is used to replace the compound represented by Formula I1 in Example 1.

[0080]

[0081] Experimental Example To compare and illustrate the performance differences of the encapsulating films in different embodiments and comparative examples, photovoltaic module samples were prepared from the encapsulating films of different embodiments and comparative examples. The photovoltaic modules were subjected to wet heat aging (double 85, DH1000), dry heat aging (105℃, 600h), and ultraviolet aging (UV225kWh) according to IEC61215. The LAB values ​​of the black (front) and white (back) sides of the photovoltaic module samples before and after aging were measured using a colorimeter (L1, a1, b1 are the initial LAB values, L2, a2, b2 are the processed LAB values; the non-cell area was tested when testing the front side of the sample). The color difference change value (ΔE) was calculated according to the following formula. ΔE=[(L1-L2) 2 +(a1-a2) 2 +(b1-b2) 2 ] 1 / 2 ; The test results are shown in Table 1.

[0082] The photovoltaic module sample to be tested consists of: an upper glass layer, a high-transparency encapsulating film (Lushan S102 co-extruded encapsulating film), solar cells, an encapsulating film to be tested (black side (front) bonded to the solar cells, white side (back) bonded to the lower glass layer), and a lower glass layer. During lamination, the heating plate temperature is 145℃, the vacuum time is 5 minutes to remove air between layers, and then three pressurizations are applied to press the layers together. The first pressurization pressure is -70 kPa, lasting 75 seconds; the second pressurization pressure is -50 kPa, lasting 75 seconds; and the third pressurization pressure is -30 kPa, lasting 15 minutes. After releasing the vacuum, the photovoltaic module sample to be tested is obtained. The solar cells are 182-size TOPCon cells, ultimately fabricated into a 24cm × 24cm small-format module, with a 0.5mm gap between the solar cells.

[0083] Table 1 Test results of different photovoltaic modules

[0084] Figure 1 and Figure 2 Comparison images of the cell areas of the components made from the adhesive film of Example 1 and Comparative Example 1 of the present invention before and after dry heat aging. Figure 3 and Figure 4 Comparative images show the color change of the back side of the components made from the adhesive film of Example 1 and Comparative Example 1 before and after dry heat aging. Figure 5 and Figure 6 Comparative images of the back side of components made from the adhesive film of Example 1 and Comparative Example 1 of the present invention before and after humid heat aging. Figure 7 and Figure 8 This is a comparison of the discoloration of the back side of the components prepared by the adhesive film in Example 1 and Comparative Example 1 of the present invention before and after ultraviolet aging. Figure 1 and Figure 2 The components have different structures. Referring to the structure and preparation method of the photovoltaic module sample to be tested above, the only difference is that the solar cells are not used. The specific component sample structure includes: upper glass, high-transparency encapsulating film (Lushan S102 co-extruded encapsulating film), encapsulating film to be tested (white side bonded to the lower glass), and lower glass, so as to more intuitively compare the color change of the front area before and after dry heat aging.

[0085] The results above show that the high-reflectivity black encapsulating film prepared with the anti-migration black pigment of the present invention, compared with the high-reflectivity black film prepared with conventional perylene black 32 (Comparative Example 1), exhibits significantly improved front-side discoloration and back-side migration during high-temperature and high-humidity aging, ultraviolet aging, and dry-heat aging. Visually, the black on the front side remains basically unchanged, and the white on the back side does not show obvious red migration, fully meeting the long-term use requirements of photovoltaic films with ΔE≤2.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-migration black pigment, characterized in that, It has the following general structural formula as shown in Equation I: ； Where R1 is , , , , At least one of them.

2. A high-reflectivity black encapsulating film, characterized in that, It includes a black layer and a white layer stacked together; the black layer includes the anti-migration black pigment as described in claim 1.

3. The high-reflectivity black encapsulating film according to claim 2, characterized in that, The black layer comprises a matrix resin and the anti-migration black pigment; The amount of the anti-migration black pigment used is 0.1% to 2% of the mass of the matrix resin.

4. The high-reflectivity black encapsulating film according to claim 2, characterized in that, The anti-migration black pigment was modified using a silane coupling agent; Preferably, the mass ratio of the silane coupling agent to the anti-migration black pigment is (0.01~0.1):

1.

5. The high-reflectivity black encapsulating film according to claim 3, characterized in that, The black layer also includes at least one of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, and a light stabilizer; Preferably, the amounts of the crosslinking agent, co-crosslinking agent, silane coupling agent, antioxidant, and light stabilizer are 0.5%–1.5%, 0.5%–1.5%, 0.1%–1%, 0.1%–0.5%, and 0.1%–0.5% of the mass of the matrix resin, respectively.

6. The high-reflectivity black encapsulating film according to claim 3, characterized in that, The white layer comprises a matrix resin, a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, a light stabilizer, and white pigment powder; Preferably, in the white layer, the amounts of the crosslinking agent, co-crosslinking agent, silane coupling agent, antioxidant, light stabilizer, and white pigment powder are 0.5%–1.5%, 0.5%–1.5%, 0.1%–1%, 0.1%–0.5%, 0.1%–0.5%, and 5%–20% of the mass of the matrix resin, respectively.

7. The high-reflectivity black encapsulating film according to claim 6, characterized in that, The white pigment powder includes at least one of titanium dioxide, silicon dioxide, hollow glass microspheres, zinc oxide, zinc sulfide, and barium sulfate.

8. The high-reflectivity black encapsulating film according to claim 6, characterized in that, The matrix resin in the black layer and the matrix resin in the white layer each independently comprise EVA resin; Preferably, the VA content in the EVA resin is not less than 25 wt%, and the melt index at 190℃ / 2.16 kg is 5 to 25 g / 10 min.

9. The high-reflectivity black encapsulating film according to claim 2, characterized in that, The thickness ratio of the black layer to the white layer is (0.2~1.5):1; Preferably, the thickness of the high-reflectivity black encapsulating film is 0.4 to 1 mm.

10. A photovoltaic module, characterized in that, Includes the high-reflectivity black encapsulating film as described in any one of claims 2 to 9.

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