Modified hydrotalcite ultraviolet inhibitor with dual energy dissipation mechanism and application of modified hydrotalcite ultraviolet inhibitor in photovoltaic packaging

Abstract

The invention relates to a modified hydrotalcite ultraviolet inhibitor with a dual energy dissipation mechanism and application of the modified hydrotalcite ultraviolet inhibitor in photovoltaic packaging. The modified hydrotalcite takes Mg-Al-Ce as main laminate metal, aromatic carboxylic acid anions are inserted between layers, rare earth ions are loaded on the surface, and a multi-center synergistic structure is formed after modification of an organic silane coupling agent. The modified hydrotalcite ultraviolet inhibitor disclosed by the invention realizes wide-spectrum ultraviolet absorption and light-heat energy dissipation through interlayer-surface dual regulation and control, and the weather resistance and optical stability of the material are remarkably improved. The modified hydrotalcite disclosed by the invention can be compounded with an EVA (Ethylene Vinyl Acetate) or POE (Polyolefin Elastomer) matrix to prepare a photovoltaic packaging adhesive film, has the advantages of high light transmittance, low yellowing, high stability and the like, solves the problems that the existing ultraviolet absorbent is easy to migrate and short in service life, and provides a novel inorganic ultraviolet protection solution for long-term stable operation of a photovoltaic module.

Description

Technical Field

[0001] This invention relates to a modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism and its application in photovoltaic packaging, belonging to the field of inorganic UV-resistant functional materials. Background Technology

[0002] Layered double hydroxides (LDHs) are a class of layered inorganic materials composed of alternating layers of positively charged metal hydroxides and exchangeable anions between the layers. They possess characteristics such as tunable structure, high thermal stability, and environmental friendliness. Due to their anion exchangeability and surface modifiability, LDHs have been widely studied and applied in fields such as catalysis, adsorption, flame retardancy, and polymer composites.

[0003] With the rapid development of the photovoltaic industry, the encapsulating films for photovoltaic modules (such as ethylene-vinyl acetate copolymer, EVA; polyolefin elastomer, POE) face problems such as yellowing, degradation, and decreased light transmittance caused by ultraviolet radiation during long-term outdoor operation. Traditional ultraviolet absorbers mainly include benzotriazole and benzophenone organic compounds. Although their initial absorption performance is excellent, they have defects such as strong migration, poor thermal stability, and short service life, making it difficult to meet the requirements of stable operation of photovoltaic modules for more than 20 years.

[0004] In recent years, researchers both domestically and internationally have begun to explore the structural designability of LDHs as carriers for inorganic UV inhibitors or absorbers to improve the UV aging resistance of organic materials. Foreign scholars have reported that by preparing ZnTi-LDH and modifying it with dodecylbenzene sulfonate (SDBS), the photothermal resistance of polypropylene can be significantly improved (RSCAdv., 2018, 8, 29789–29796).

[0005] However, international research on LDH UV inhibitors specifically for photovoltaic encapsulation films is still in its early stages. Existing LDHs are mostly single-metal systems (such as Zn2Al-LDH), which primarily improve the UV absorption range through organic molecule intercalation, but have not yet systematically addressed the issues of low energy conversion efficiency and poor interfacial stability. Furthermore, international research largely focuses on conventional polymers (such as PP and PE), without specifically optimizing for the core requirements of photovoltaic encapsulation materials, which must balance optical transparency, long-term weather resistance, and thermal stability.

[0006] Domestically, researchers have made some progress in the multi-metal ion regulation, anion intercalation, and surface coupling modification of LDH, but its application in photovoltaic packaging still faces three major bottlenecks: First, the stability of interlayer organic molecules is insufficient, making it difficult to maintain its absorption capacity in the long term; second, the compatibility between inorganic layers and organic substrates is poor, which easily leads to light scattering and decreased transparency; and third, the lack of energy dissipation mechanism design means that the material is still prone to thermal degradation under strong ultraviolet conditions.

[0007] Therefore, there is an urgent need to develop a modified hydrotalcite UV inhibitor with controllable structure, good interface compatibility, and high energy dissipation efficiency. Through interlayer intercalation and surface synergistic functionalization, a synergistic effect of UV absorption and photothermal conversion can be achieved. While ensuring optical transparency, the material's resistance to UV aging and long-term stability can be significantly improved, providing a new, efficient, environmentally friendly, and industrially viable protection solution for photovoltaic module encapsulation materials. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism and its application in photovoltaic packaging.

[0009] The purpose of this invention is to overcome the defects of existing photovoltaic encapsulation films, such as easy aging and light transmission decay under ultraviolet irradiation, as well as the poor thermal stability and strong migration of organic absorbents. It provides a modified hydrotalcite ultraviolet inhibitor with controllable structure, broad absorption spectrum, and high stability. Through interlayer intercalation and surface synergistic functionalization, it achieves a synergistic effect of ultraviolet absorption and energy dissipation, thereby significantly improving the service life and power retention rate of photovoltaic modules and achieving efficient, long-term, and environmentally friendly ultraviolet protection.

[0010] To achieve the above objectives, the present invention employs the following technical solution:

[0011] A modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism is disclosed. The modified hydrotalcite UV inhibitor exhibits a three-dimensional network structure assembled from nanosheets. Each nanosheet has a layered structure, with uniform layer structure and no obvious physical mixing. The layers contain aromatic carboxylic acid anions with π-conjugated structures. Rare earth ions are loaded on the surface of the layers, and the surface of the layers is modified with a silane coupling agent.

[0012] According to a preferred embodiment of the present invention, the interlayer spacing is 0.8-1.2 nm, the plate size is 100-500 nm, and the thickness-to-diameter ratio is 1:3-1:8.

[0013] The modified hydrotalcite UV inhibitor composite structure of this invention achieves a triple functional synergistic mechanism of "interlayer absorption-surface dissipation-interfacial stability": 1) Aromatic anion intercalation regulates the interlayer energy level structure, forming UV absorption centers through π-π electron delocalization effect, thus broadening the UV absorption bandwidth; 2) Rare earth ions are loaded on the surface of the layers to introduce light-heat energy dissipation channels. Rare earth provides non-radiative relaxation paths, safely releasing absorbed energy in the form of heat; 3) The surface of the layers is modified with silane coupling agents. The organosilicon coupling layer enhances the interfacial bonding between the inorganic layers and the polymer matrix, avoiding aggregation and light scattering, and improving optical transparency.

[0014] The second objective of this invention is to provide a method for preparing the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism described above.

[0015] A method for preparing a modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism, wherein the modified hydrotalcite is prepared by a three-step method of co-precipitation, intercalation, and surface modification, with Mg–Al–Ce as the main layer metal.

[0016] Specifically, the preparation method of the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism includes the following steps:

[0017] (1) Raw material preparation: dissolve magnesium source, aluminum source and cerium source in deionized water to obtain solution A; dissolve aromatic carboxylic acid anion source in deionized water to prepare solution B;

[0018] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B, pH was maintained at 10±0.2, the reaction was stirred and aged, centrifuged, washed and dried to obtain the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor;

[0019] (3) Surface rare earth modification and silane coupling treatment: The intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor was dispersed in ethanol, ultrasonically dispersed, and then a rare earth source ethanol solution was added and magnetically stirred for adsorption; then silane coupling agent and crosslinking aid were added, and the reaction was carried out at a constant temperature. After the reaction was completed, the mixture was centrifuged, washed, vacuum dried, ground and sieved to obtain surface rare earth modified Mg-Al-Ce / aromatic carboxylic acid-rare earth hydrotalcite powder.

[0020] According to a preferred embodiment of the present invention, in step (1), the magnesium source is magnesium nitrate hexahydrate, the aluminum source is aluminum nitrate nonahydrate, and the cerium source is cerium nitrate hexahydrate.

[0021] According to a preferred embodiment of the present invention, in step (1), the molar ratio of magnesium source, aluminum source and cerium source is (0.1-0.5):(0.05-0.3):(0.01-0.1).

[0022] According to a preferred embodiment of the present invention, in step (1), the molar ratio of magnesium source to deionized water is (0.1-0.5):(100-800), unit: mol / mL.

[0023] According to a preferred embodiment of the present invention, in step (1), the aromatic carboxylic acid anion source is selected from sodium 4-hydroxybenzoate, sodium p-hydroxycinnamate, and sodium salicylate.

[0024] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the aromatic carboxylic acid anion source to the volume ratio of deionized water is (0.01-0.1):(100-800), unit: mol / mL.

[0025] According to a preferred embodiment of the present invention, in step (2), the volume ratio of solution A to solution B is 1:(1-10).

[0026] According to a preferred embodiment of the present invention, in step (2), solution A is added dropwise to solution B at a rate of 1-3 mL / min.

[0027] According to a preferred embodiment of the present invention, in step (2), the pH of the system is maintained at 10 ± 0.2 using a 1 mol / L NaOH solution.

[0028] According to a preferred embodiment of the present invention, in step (2), the stirring reaction time is 1-5 h, and the aging is aging at 70-90°C for 10-14 h.

[0029] According to a preferred embodiment of the present invention, in step (3), the mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to ethanol is (1-5):100, unit: g / mL.

[0030] According to a preferred embodiment of the present invention, in step (3), the concentration of the rare earth source in the ethanol solution of the rare earth source is 0.01-0.1 mol / L.

[0031] According to a preferred embodiment of the present invention, in step (3), the rare earth source is Ce(NO3)3, Eu(NO3)3 or La(NO3)3.

[0032] According to a preferred embodiment of the present invention, in step (3), the mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to the ethanol solution of the rare earth source is (1-5):50, unit: g / mL.

[0033] According to a preferred embodiment of the present invention, in step (3), the magnetic stirring adsorption time is 1-5 hours.

[0034] According to a preferred embodiment of the present invention, in step (3), the silane coupling agent is γ-aminopropyltriethoxysilane KH550.

[0035] According to a preferred embodiment of the present invention, in step (3), the crosslinking aid is tetraethoxysilane (TEOS).

[0036] According to a preferred embodiment of the present invention, in step (3), the mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to the silane coupling agent is (1-5):(0.4-0.8), unit: g / mL.

[0037] According to a preferred embodiment of the present invention, in step (3), the mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to the crosslinking aid is (1-5):(0.1-0.3), unit: g / mL.

[0038] According to a preferred embodiment of the present invention, in step (3), the constant temperature reaction temperature is 60-80℃, the reaction time is 1-5h, the vacuum drying temperature is 70-90℃, and the reaction time is 8-12h.

[0039] A third objective of this invention is to provide the application of the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism described above.

[0040] The application of modified hydrotalcite UV inhibitors with dual energy dissipation mechanisms in photovoltaic encapsulation film materials.

[0041] According to a preferred embodiment of the present invention, the application method is as follows:

[0042] 1) The modified hydrotalcite UV inhibitor is uniformly dispersed in an ethylene-vinyl acetate copolymer (EVA) or polyolefin elastomer (POE) matrix, with the amount of modified hydrotalcite UV inhibitor added being 0.1-2 wt% of the matrix mass;

[0043] 2) A packaging film with a thickness of 0.3-0.5 mm is obtained by melt blending and extrusion.

[0044] Technical features and advantages of the present invention:

[0045] 1. This invention introduces a composite protection system of "interlayer organic absorption – surface inorganic dissipation – interfacial chemical coupling" into hydrotalcite materials for the first time, achieving synergistic optimization of structure, mechanism and performance, realizing broadband ultraviolet absorption (280–400 nm), with an absorption efficiency more than 2.5 times that of unmodified magnesium aluminum hydrotalcite, and a transmittance of ≥90% in the visible light region (400-1100 nm). It not only solves the migration and failure problems of traditional organic ultraviolet absorbers, but also breaks through the technical bottleneck of inorganic fillers in photovoltaic transparent materials that take into account both protection and light transmission, and has significant innovation and industrial application prospects.

[0046] 2. The modified hydrotalcite UV inhibitor prepared in this invention rapidly dissipates energy through the photo-thermal conversion pathway after absorbing UV energy, significantly reducing the photodegradation rate of photovoltaic films.

[0047] 3. The modified hydrotalcite UV inhibitor prepared by this invention is uniformly dispersed in EVA or POE matrix, does not affect visible light transmittance (maintains ≥91%), and does not migrate or precipitate.

[0048] 4. After 1200 hours of accelerated UVB aging test, the yellowness index of the film prepared with modified hydrotalcite UV inhibitor increased by less than 2 and the light transmittance decreased by less than 5%, which is far superior to the traditional benzotriazole system.

[0049] 5. The materials used in this invention are green and environmentally friendly, and have high process compatibility. They can be directly applied to existing photovoltaic packaging production lines without additional equipment investment. Attached Figure Description

[0050] Figure 1 This is a scanning electron microscope image of the intercalated Mg-Al-Ce / 4-hydroxybenzoate hydrotalcite precursor prepared in Example 1;

[0051] Figure 2 It is Mg-Al-Ce / 4-hydroxybenzoate –Ce 3+ Scanning electron microscope image of the surface layer of the surface-modified hydrotalcite composite EVA photovoltaic film. Detailed Implementation

[0052] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0053] Example 1:

[0054] Mg-Al-Ce / 4-hydroxybenzoate–Ce 3+ Preparation of surface-modified hydrotalcite:

[0055] (1) Raw material preparation: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium 4-hydroxybenzoate and dissolve it in 200 mL of deionized water to prepare solution B.

[0056] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. The pH was maintained at 10 ± 0.2 using NaOH solution (1 mol / L). After stirring for 2 h, the mixture was aged at 80 °C for 12 h. After centrifugation, washing, and drying, the intercalated Mg-Al-Ce / 4-hydroxybenzoate hydrotalcite precursor was obtained. Scanning electron microscopy showed... Figure 1 ;

[0057] (3) Surface Ce 3+Modification and silane coupling treatment: 2.0 g of the intercalated Mg-Al-Ce / 4-hydroxybenzoate hydrotalcite precursor obtained in step (2) was dispersed in 100 mL of ethanol. After ultrasonic dispersion for 20 min, 50 mL of 0.05 mol / L Ce(NO3)3 ethanol solution was added, and the mixture was magnetically stirred and adsorbed for 4 h. Subsequently, 0.5 mL of KH550 (γ-aminopropyltriethoxysilane) and a small amount of crosslinking aid TEOS (0.2 mL) were added, and the mixture was reacted at 70 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol, dried under vacuum at 80 °C for 10 h, and ground through a 200-mesh sieve to obtain Ce³⁺-modified Mg-Al-Ce / 4-hydroxybenzoate–Ce. 3+ Hydrotalcite powder.

[0058] Example 2:

[0059] Mg-Al-Ce / p-hydroxycinnamate–Ce 3+ Preparation of surface-modified hydrotalcite:

[0060] (1) Raw material preparation: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium p-hydroxycinnamate and dissolve it in 200 mL of deionized water to prepare solution B.

[0061] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. NaOH solution (1 mol / L) was used to maintain pH = 10 ± 0.2. After stirring for 2 h, the mixture was aged at 80 °C for 12 h. After centrifugation, washing and drying, the intercalated Mg-Al-Ce / p-hydroxycinnamate hydrotalcite precursor was obtained.

[0062] (3) Surface Ce 3+ Modification and silane coupling treatment: 2.0 g of the Mg-Al-Ce / p-hydroxycinnamate hydrotalcite precursor obtained in step (2) was dispersed in 100 mL of ethanol. After ultrasonic dispersion for 20 min, 50 mL of 0.05 mol / L Ce(NO3)3 ethanol solution was added, and the mixture was magnetically stirred and adsorbed for 4 h. Subsequently, 0.5 mL of KH550 (γ-aminopropyltriethoxysilane) and a small amount of crosslinking aid TEOS (0.2 mL) were added, and the mixture was reacted at 70 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol, dried under vacuum at 80 °C for 10 h, and ground through a 200-mesh sieve to obtain the Ce-coated surface. 3+ Modified Mg–Al–Ce / p-hydroxycinnamate–Ce 3+ Hydrotalcite powder.

[0063] Example 3:

[0064] Mg-Al-Ce / Salicylate–Ce 3+ Preparation of surface-modified hydrotalcite:

[0065] (1) Raw material preparation: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium salicylate and dissolve it in 200 mL of deionized water to prepare solution B.

[0066] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. NaOH solution (1 mol / L) was used to maintain pH=10±0.2. After stirring for 2 h, the mixture was aged at 80℃ for 12 h. After centrifugation, washing and drying, the intercalated Mg-Al-Ce / salicylate hydrotalcite precursor was obtained.

[0067] (3) Surface Ce 3+ Modification and silane coupling treatment: 2.0 g of the Mg-Al-Ce / salicylate hydrotalcite precursor obtained in step (2) was dispersed in 100 mL of ethanol. After ultrasonic dispersion for 20 min, 50 mL of 0.05 mol / L Ce(NO3)3 ethanol solution was added, and the mixture was magnetically stirred and adsorbed for 4 h. Subsequently, 0.5 mL of KH550 (γ-aminopropyltriethoxysilane) and a small amount of crosslinking aid TEOS (0.2 mL) were added, and the mixture was reacted at 70 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol, dried under vacuum at 80 °C for 10 h, and ground through a 200-mesh sieve to obtain the Ce-coated surface. 3+ Modified Mg-Al-Ce / Salicylate–Ce 3+ Hydrotalcite powder.

[0068] Example 4:

[0069] Mg-Al-Ce / p-hydroxycinnamate–Eu 3+ Preparation of surface-modified hydrotalcite:

[0070] (1) Preparation of raw materials: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium p-hydroxycinnamate and dissolve it in 200 mL of deionized water to prepare solution B;

[0071] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. NaOH solution (1 mol / L) was used to maintain pH = 10 ± 0.2. After stirring for 2 h, the mixture was aged at 80 °C for 12 h. After centrifugation, washing and drying, the intercalated Mg-Al-Ce / p-hydroxycinnamate hydrotalcite precursor was obtained.

[0072] (3) Surface Eu 3+ Modification and silane coupling treatment: 2.0 g of the Mg-Al-Ce / p-hydroxycinnamate hydrotalcite precursor obtained in step (2) was dispersed in 100 mL of ethanol. After ultrasonic dispersion for 20 min, 50 mL of 0.05 mol / L Eu(NO3)3 ethanol solution was added, and the mixture was magnetically stirred and adsorbed for 4 h. Subsequently, 0.5 mL of KH550 (γ-aminopropyltriethoxysilane) and a small amount of crosslinking aid TEOS (0.2 mL) were added, and the mixture was reacted at 70 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol, dried under vacuum at 80 °C for 10 h, and ground through a 200-mesh sieve to obtain surface Eu 3+ Modified Mg-Al-Ce / p-hydroxycinnamate –Eu 3+ Hydrotalcite powder.

[0073] Example 5:

[0074] Mg-Al-Ce / Salicylate–La 3+ Preparation of surface-modified hydrotalcite

[0075] (1) Raw material preparation: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium salicylate and dissolve it in 200 mL of deionized water to prepare solution B.

[0076] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. NaOH solution (1 mol / L) was used to maintain pH = 10 ± 0.2. After stirring for 2 h, the mixture was aged at 80 °C for 12 h. After centrifugation, washing and drying, the intercalated Mg-Al-Ce / salicylate hydrotalcite precursor was obtained.

[0077] (3) Surface La 3+ Modification and silane coupling treatment: 2.0 g of Mg-Al-Ce / salicylate hydrotalcite precursor was dispersed in 100 mL of ethanol and ultrasonically dispersed for 20 min. Then, 50 mL of 0.05 mol / L La(NO3)3 ethanol solution was added, and the mixture was magnetically stirred for 4 h for adsorption. Subsequently, 0.5 mL of KH550 (γ-aminopropyltriethoxysilane) and a small amount of crosslinking aid TEOS (0.2 mL) were added, and the mixture was reacted at 70 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol, vacuum dried at 80 °C for 10 h, and ground through a 200-mesh sieve to obtain the surface La 3+ Modified Mg–Al–Ce / Salicylic Acid–La 3+ Hydrotalcite powder.

[0078] Example 6:

[0079] Application of modified hydrotalcite in EVA photovoltaic films

[0080] 0.8 parts of the modified hydrotalcite prepared in Examples 1-5 were melt-blended with 100 parts of EVA resin (VA content 28%), 1.0 part of dicumyl peroxide, 1.2 parts of triallyl isocyanurate, and 0.5 parts of antioxidant 1010 / 168 mixture at 160°C. The resulting mixture was then extruded and pressed into a photovoltaic encapsulation film with a thickness of 0.45 mm. Five different photovoltaic encapsulation films were prepared and then laminated with photovoltaic cells for encapsulation.

[0081] Comparative Example 1

[0082] 0.8 parts of unmodified commercially available magnesium aluminum hydrotalcite, 100 parts of EVA resin (VA content 28%), 1.0 part of dicumyl peroxide, 1.2 parts of triallyl isocyanurate, and 0.5 parts of antioxidant 1010 / 168 mixture were melt-blended at 160℃ and pressed into a photovoltaic encapsulation film with a thickness of 0.45 mm.

[0083] Comparative Example 2

[0084] 0.8 parts of commercially available benzotriazole UV absorber (UV-531) were melt-blended with 100 parts of EVA resin (VA content 28%), 1.0 part of dicumyl peroxide, 1.2 parts of triallyl isocyanurate, and 0.5 parts of antioxidant 1010 / 168 mixture at 160°C, and then pressed into a photovoltaic encapsulation film with a thickness of 0.45 mm.

[0085] Comparative Example 3

[0086] Preparation of unmodified Mg–Al–Ce / 4-hydroxybenzoate hydrotalcite:

[0087] (1) Preparation of raw materials: Weigh 0.30 mol of magnesium nitrate hexahydrate, 0.10 mol of aluminum nitrate nonahydrate and 0.02 mol of cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A; Weigh 0.05 mol of sodium 4-hydroxybenzoate and dissolve it in 200 mL of deionized water to prepare solution B.

[0088] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B at a rate of 2 mL / min. NaOH solution (1 mol / L) was used to maintain pH=10±0.2. After stirring for 2 h, the solution was aged at 80℃ for 12 h. After centrifugation, washing and drying, Mg–Al–Ce / 4-hydroxybenzoate hydrotalcite with unmodified surface was obtained.

[0089] 0.8 parts of unmodified Mg–Al–Ce / 4-hydroxybenzoate hydrotalcite were melt-blended with 100 parts of EVA resin (VA content 28%), 1.0 part of dicumyl peroxide, 1.2 parts of triallyl isocyanurate, and 0.5 parts of antioxidant 1010 / 168 mixture at 160°C, and then pressed into a photovoltaic encapsulation film with a thickness of 0.45 mm.

[0090] Comparative Example 4

[0091] Preparation of Mg-Al-Ce / carbonate hydrotalcite:

[0092] (1) Raw material preparation: Weigh 0.30 mol magnesium nitrate hexahydrate, 0.10 mol aluminum nitrate nonahydrate and 0.02 mol cerium nitrate hexahydrate and dissolve them in 200 mL of deionized water to obtain solution A.

[0093] (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to sodium carbonate solution at a rate of 2 mL / min. Sodium carbonate was added to maintain pH=10±0.2. After stirring for 2 h, the solution was aged at 80℃ for 12 h, centrifuged, washed, and dried. The solution was then vacuum dried at 80℃ for 10 h and ground through a 200-mesh sieve to obtain Mg-Al-Ce / carbonate hydrotalcite powder.

[0094] 0.8 parts of Mg-Al-Ce / carbonate hydrotalcite powder, 100 parts of EVA resin (VA content 28%), 1.0 part of dicumyl peroxide, 1.2 parts of triallyl isocyanurate, and 0.5 parts of antioxidant 1010 / 168 mixture were melt-blended at 160℃ and pressed into a photovoltaic encapsulation film with a thickness of 0.45 mm.

[0095] Experimental example:

[0096] The UV resistance, light transmittance attenuation rate, peel strength, and elongation at break of the five different photovoltaic encapsulation films in Example 6 and the photovoltaic encapsulation films in Comparative Examples 1-4 were tested. The performance test results are shown in Table 1.

[0097] Table 1. Performance comparison of different modified hydrotalcite examples and control samples

[0098]

[0099] As can be seen from Table 1,

[0100] 1. Modified LDH significantly improved the UV resistance of EVA encapsulation films, with the p-hydroxycinnamate-Eu³⁺ system (Example 6) showing the best performance and the smallest increase in yellowness, only 1.5.

[0101] 2. Intralayer rare earth ion doping, interlayer aromatic organic acid intercalation, and surface rare earth modification have a synergistic enhancement effect.

[0102] 3. Rare earth surface modification significantly improves energy dissipation efficiency, prevents local photothermal accumulation, and enhances thermal stability.

[0103] 4. Compared with the comparative example, the material of the present invention is stable in the long term, has no precipitation, and has high transparency, and has excellent potential for photovoltaic encapsulation applications.

Claims

1. A modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism, wherein the modified hydrotalcite UV inhibitor exhibits a three-dimensional network structure assembled from nanosheets, each nanosheet having a layered structure, uniform layer structure, no obvious physical mixing, aromatic carboxylic acid anions with π-conjugated structure between layers, rare earth ions loaded on the surface of the layers, and the surface of the layers modified with silane coupling agents.

2. The modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism according to claim 1, characterized in that, The interlayer spacing is 0.8-1.2 nm, the plate size is 100-500 nm, and the thickness-to-diameter ratio is 1:3-1:

8.

3. The method for preparing the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism as described in claim 1, wherein the modified hydrotalcite is prepared by a three-step method of co-precipitation, intercalation, and surface modification, with Mg-Al-Ce as the main layer metal.

4. The preparation method of the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism as described in claim 1, comprising the following steps: (1) Raw material preparation: dissolve magnesium source, aluminum source and cerium source in deionized water to obtain solution A; dissolve aromatic carboxylic acid anion source in deionized water to prepare solution B; (2) Coprecipitation and crystallization: Under nitrogen protection, solution A was added dropwise to solution B, pH was maintained at 10±0.2, the reaction was stirred and aged, and then centrifuged, washed and dried to obtain the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor; (3) Surface rare earth modification and silane coupling treatment: The intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor was dispersed in ethanol, ultrasonically dispersed, and then a rare earth source ethanol solution was added and magnetically stirred for adsorption; then silane coupling agent and crosslinking aid were added, and the reaction was carried out at a constant temperature. After the reaction was completed, the mixture was centrifuged, washed, vacuum dried, ground and sieved to obtain surface rare earth modified Mg-Al-Ce / aromatic carboxylic acid-rare earth hydrotalcite powder.

5. The preparation method according to claim 4, characterized in that, In step (1), the magnesium source is magnesium nitrate hexahydrate, the aluminum source is aluminum nitrate nonahydrate, and the cerium source is cerium nitrate hexahydrate. The molar ratio of the magnesium source, aluminum source, and cerium source is (0.1-0.5):(0.05-0.3):(0.01-0.1). The molar amount of the magnesium source to the volume ratio of deionized water is (0.1-0.5):(100-800), unit: mol / mL. The aromatic carboxylic acid anion source is selected from sodium 4-hydroxybenzoate, sodium p-hydroxycinnamate, or sodium salicylate. The molar amount of the aromatic carboxylic acid anion source to the volume ratio of deionized water is (0.01-0.1):(100-800), unit: mol / mL.

6. The preparation method according to claim 4, characterized in that, In step (2), the volume ratio of solution A to solution B is 1:(1-10). Solution A is added dropwise to solution B at a rate of 1-3 mL / min. The pH of the system is maintained at 10±0.2 using 1 mol / L NaOH solution. The stirring reaction time is 1-5 h, and the aging is carried out at 70-90℃ for 10-14 h.

7. The preparation method according to claim 4, characterized in that, In step (3), the mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to ethanol is (1-5):100, unit: g / mL. The concentration of rare earth source in the ethanol solution of rare earth source is 0.01-0.1mol / L. The rare earth source is Ce(NO3)3, Eu(NO3)3 or La(NO3)3. The mass-to-volume ratio of the intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to the ethanol solution of rare earth source is (1-5):50, unit: g / mL.

8. The preparation method according to claim 4, characterized in that, In step (3), the magnetic stirring adsorption time is 1-5 h, the silane coupling agent is γ-aminopropyltriethoxysilane KH550, the crosslinking aid is tetraethoxysilane TEOS, the mass-volume ratio of intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to silane coupling agent is (1-5):(0.4-0.8), unit: g / mL, the mass-volume ratio of intercalated Mg-Al-Ce / aromatic carboxylic acid hydrotalcite precursor to crosslinking aid is (1-5):(0.1-0.3), unit: g / mL, the isothermal reaction temperature is 60-80℃, the reaction time is 1-5 h, the vacuum drying temperature is 70-90℃, and the reaction time is 8-12 h.

9. The application of the modified hydrotalcite UV inhibitor with a dual energy dissipation mechanism as described in claim 1, applied to photovoltaic encapsulation film materials.

10. The application according to claim 9, characterized in that, The application method is as follows: 1) The modified hydrotalcite UV inhibitor is uniformly dispersed in an ethylene-vinyl acetate copolymer (EVA) or polyolefin elastomer (POE) matrix, with the amount of modified hydrotalcite UV inhibitor added being 0.1-2 wt% of the matrix mass; 2) A packaging film with a thickness of 0.3-0.5 mm is obtained by melt blending and extrusion.

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