High-flame-retardant basalt fiber photovoltaic substrate and preparation method thereof

Abstract

The invention relates to the technical field of photovoltaic materials, and discloses a high-flame-retardant basalt fiber photovoltaic substrate and a preparation method thereof.The photovoltaic substrate is prepared from, by weight, 60-70 parts of basalt fibers, 30-40 parts of bisphenol A epoxy resin, 5-15 parts of a curing agent, 5-8 parts of modified nano core-shell particles, 3-5 parts of modified magnesium-aluminum double hydroxide, 3-5 parts of a coupling agent and 0.05-0.15 part of an accelerant; the modified nano core-shell particles are obtained by coating an h-BN doped polyurethane elastomer with DOPO-loaded mesoporous microspheres, and the mesoporous microspheres are obtained by coating mesoporous silica on the surface of nano Fe3O4; the modified magnesium-aluminum double hydroxide is obtained by performing intercalation modification on lamellar magnesium-aluminum double hydroxide through lauryl sodium sulfate and then grafting the lamellar magnesium-aluminum double hydroxide with a triazine heat stabilizer, and the triazine heat stabilizer is a silane-modified hindered phenol heat stabilizer; a single-layer basalt fiber and epoxy resin composite structure design is adopted, a traditional glass front plate and a traditional polymer back plate are replaced, and the photovoltaic substrate has the advantages of being light in weight, high in flame retardance and high in aging resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic materials, and in particular relates to a highly flame-retardant basalt fiber photovoltaic substrate and a preparation method thereof. Background Art

[0002] Solar energy is nature's most abundant renewable energy source, which can be converted into electricity through photovoltaic modules. These modules offer unique advantages and enormous potential for development and application. A photovoltaic module, consisting of several individual solar cells connected in series and parallel, and tightly packaged, is the smallest, indivisible combination of photovoltaic cells required for photovoltaic power generation. However, the cells in a typical photovoltaic module are typically connected using either single or string welding with ribbons. The front electrode of the preceding cell is connected to the back electrode of the following cell, then heated and welded together. Cells are then connected in series to form a cell string. The welded cell string is then laid out and welded to a first busbar. The lead-out ends of the first busbar are then connected in series with bypass diodes in the junction box, leading to the positive and negative electrodes. Finally, a series of assembly processes are employed to form the photovoltaic module.

[0003] Traditional photovoltaic modules generally adopt a sandwich structure of "glass / encapsulation material / cell / encapsulation material / backsheet", with frames added around them to ensure the mechanical properties of the module and facilitate installation. However, this combination of glass front sheet and polymer back sheet will result in a photovoltaic module weight of ≥14kg / m 2 , making transportation and installation inconvenient. Furthermore, the backsheet is made of a flammable polymer, making overall fire protection weak. Furthermore, the double-layer adhesive interface leads to the risk of delamination due to hygrothermal aging, which can cause the packaging structure to fail. Therefore, a lightweight, flame-retardant, and aging-resistant photovoltaic substrate material is urgently needed to improve the overall performance of photovoltaic modules. Summary of the Invention

[0004] In order to address the deficiencies mentioned in the above-mentioned background technology, the purpose of the present invention is to provide a highly flame-retardant basalt fiber photovoltaic substrate and a preparation method thereof. The present invention adopts a single-layer basalt fiber and epoxy resin composite structure design to replace the traditional glass front plate and polymer back plate. The photovoltaic substrate has the characteristics of lightweight, high flame retardancy and high aging resistance. The added modified nano core-shell particles and modified magnesium aluminum double hydroxide achieve synergistic enhancement of the mechanical, flame retardant and aging resistance of the composite material through multi-scale structural design and multifunctional chemical modification.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 60-70 parts of basalt fiber, 30-40 parts of bisphenol A epoxy resin, 5-15 parts of a curing agent, 5-8 parts of modified nano core-shell particles, 3-5 parts of modified magnesium aluminum double hydroxide, 3-5 parts of a coupling agent, and 0.05-0.15 parts of an accelerator. The modified nano core-shell particles are DOPO-loaded mesoporous microspheres coated with h-BN-doped polyurethane elastomer, and the mesoporous microspheres are nano-Fe3O4 surface coated with mesoporous silica; The modified magnesium aluminum double hydroxide is a lamellar magnesium aluminum double hydroxide modified by sodium dodecyl sulfate intercalation and then grafted with a triazine heat stabilizer, and the triazine heat stabilizer is a silane-modified hindered phenol heat stabilizer.

[0006] Preferably, the curing agent is one of diaminodiphenylmethane, diaminodiphenyl sulfone and methyltetrahydrophthalic anhydride, the coupling agent is one of silane coupling agent KH550, silane coupling agent KH560, titanate coupling agent NDZ101 and aluminate coupling agent DL411, and the accelerator is one of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 4-dimethylaminopyridine and 2-ethyl-4-methylimidazole.

[0007] Preferably, the preparation method of the modified nano core-shell particles comprises the following steps: A. Dissolve hexadecyltrimethylammonium bromide in deionized water, add nano-Fe3O4 to the hexadecyltrimethylammonium bromide solution, ultrasonically disperse for 20-40 minutes, add 10mM NaOH solution, stir evenly, then add ethyl orthosilicate ethanol solution, stir at 60℃ for 12-24 hours, centrifuge and wash, vacuum dry, and finally calcine at 550℃ for 4-6 hours to obtain mesoporous silica-coated nano-Fe3O4 microspheres; B. Dispersing the mesoporous silica-coated nano-Fe3O4 microspheres in anhydrous ethanol, adding 3-aminopropyltriethoxysilane, reflux at 80°C for 4-8 hours, centrifugally washing, and vacuum drying to obtain amino-modified mesoporous microspheres. The amino-modified mesoporous microspheres are immersed in an acetone solution of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically treated for 1-2 hours, and allowed to stand under -0.1 MPa vacuum for 8-12 hours. After filtration, washing, and vacuum drying, DOPO-loaded mesoporous microspheres are obtained. C. Add poly(hexamethylene adipate) and isophorone diisocyanate into a reactor and heat to 80°C. React for 1-2 hours under N2 protection. Then add 1,4-butanediol and 2,2-dimethylolpropionic acid to extend the chain. Continue to react for 2-4 hours to obtain a polyurethane prepolymer. D. Disperse hexagonal boron nitride in Tris-HCl buffer, add dopamine hydrochloride, stir at room temperature for 12-24 hours, and centrifuge to obtain polydopamine-coated hexagonal boron nitride. Disperse the polydopamine-coated hexagonal boron nitride in 90 vol% ethanol solution, add 3-aminopropyltriethoxysilane, reflux at 80°C for 4-8 hours, and centrifuge to obtain modified hexagonal boron nitride. E. Polyurethane prepolymer and modified hexagonal boron nitride were added to acetone in a mass ratio of 8-10:1 and ultrasonically dispersed to obtain an oil phase. DOPO-loaded mesoporous microspheres were dispersed in a polyvinyl alcohol solution and homogenized to obtain an aqueous phase. The oil phase was added dropwise to the aqueous phase and mechanically stirred to form an O / W emulsion. The temperature was raised to 60°C to evaporate the acetone to obtain polyurethane-coated core-shell particles. Triethylamine and epichlorohydrin were added and reacted at 60°C for 3-5 hours. The mixture was centrifuged, washed, and vacuum dried to obtain modified nano core-shell particles.

[0008] Preferably, in step A, the mass ratio of nano-Fe3O4, hexadecyltrimethylammonium bromide and ethyl orthosilicate is 1:1:2-4.

[0009] Preferably, in step B, the mass ratio of the mesoporous silica-coated nano-Fe3O4 microspheres, 3-aminopropyltriethoxysilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:0.2:0.5~1.5.

[0010] Preferably, in step C, the mass ratio of poly(hexamethylene adipate), isophorone diisocyanate, 1,4-butanediol and 2,2-dimethylolpropionic acid is 1:1.8~2.2:0.2:0.1.

[0011] Preferably, in step D, the mass ratio of hexagonal boron nitride, dopamine hydrochloride and 3-aminopropyltriethoxysilane is 1:0.2 to 0.5:0.2.

[0012] Preferably, the preparation method of the modified magnesium aluminum double hydroxide comprises the following steps: (1) Sodium dodecyl sulfate was dissolved in deionized water to obtain a 0.1-0.5 mol / L sodium dodecyl sulfate solution, magnesium aluminum double hydroxide was added to the sodium dodecyl sulfate solution, stirred at 60-80°C for 12-24 hours under nitrogen protection, centrifuged, washed with deionized water / ethanol 3-5 times, and dried in vacuo at 60°C to obtain intercalated modified magnesium aluminum double hydroxide; (2) 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and triethylamine were dissolved in 1,4-dioxane, and 1,1'-carbonyldiimidazole was slowly added dropwise after cooling in an ice bath. The mixture was stirred and reacted for 40-60 minutes in an ice bath. Cyanuric chloride was dissolved in 1,4-dioxane and added dropwise to the reaction system. The mixture was reacted in an ice bath for 1-2 hours, and then the temperature was slowly raised to 40-50°C. The reaction was continued for 3-4 hours. Finally, 3-aminopropyltriethoxysilane was added to the system, and the temperature was raised to 70-80°C for 3-4 hours. Saturated NaHCO3 was added to quench the mixture. The organic phase was extracted with dichloromethane, dried with anhydrous magnesium sulfate, and purified by column chromatography after rotary evaporation to obtain a triazine thermal stabilizer. (3) The intercalated modified magnesium aluminum double hydroxide obtained in step (1) is added to an ethanol solution for ultrasonic dispersion, and then a triazine thermal stabilizer is added, ultrasonically treated for 20 to 40 minutes, heated to 50 to 60° C. for reaction for 3 to 5 hours, filtered, washed, and dried to obtain the modified magnesium aluminum double hydroxide.

[0013] Preferably, the molar ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 1,1'-carbonyldiimidazole, cyanuric chloride and 3-aminopropyltriethoxysilane is 2:2:1:1, and the mass ratio of intercalated modified magnesium aluminum double hydroxide and triazine thermal stabilizer is 1:0.2~0.4.

[0014] A method for preparing a highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin, modified nano core-shell particles, modified magnesium aluminum double hydroxide, and a coupling agent at 60° C. for 1 to 2 hours, add a curing agent and an accelerator, and perform vacuum degassing at -0.1 MPa for 5 to 15 minutes to obtain an epoxy resin adhesive; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Apply a vertical magnetic field of 0.5 to 1 T, and heat and cure in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain a highly flame-retardant basalt fiber photovoltaic substrate.

[0015] Beneficial effects of the present invention: The highly flame-retardant basalt fiber photovoltaic substrate of the present invention adopts a single-layer basalt fiber and epoxy resin composite structure design, replacing the traditional glass front panel and polymer back panel. The photovoltaic substrate is lightweight, highly flame-retardant and highly aging-resistant. The added modified nano core-shell particles and modified magnesium aluminum double hydroxide achieve synergistic enhancement of the mechanical, flame-retardant and aging-resistant properties of the composite material through multi-scale structural design (nano core-shell-micron layer) and multifunctional chemical modification (DOPO flame retardancy, triazine antioxidant, h-BN thermal conductivity).

[0016] The modified nano-core-shell particles consist of a magnetic nano-Fe₃O₄ core coated sequentially with mesoporous silica and a polyurethane soft shell. The mesoporous silica is adsorbed with a DOPO flame retardant, while the polyurethane is uniformly dispersed with polydopamine-coated hexagonal boron nitride. The rigid support provided by the nano-Fe₃O₄ and mesoporous silica cores inhibits plastic deformation of the matrix, while the elastic deformation of the polyurethane soft shell absorbs impact energy, enhancing impact strength through crack deflection and bridging effects. The high-modulus h-BN dispersed in the resin matrix effectively transfers load and improves flexural strength, thereby enhancing the material's mechanical properties. DOPO releases PO· free radicals that capture H· / OH·, inhibiting the combustion chain reaction. The layered structure of h-BN promotes the formation of a dense carbon layer, while Fe₃O₄ catalyzes the graphitization of the carbon layer, enhancing the barrier effect and improving the material's flame retardancy. By applying a perpendicular magnetic field, the Fe3O4 cores are induced to align in a directional manner. At the same time, the h-BN nanosheets are oriented along the direction of the magnetic field under the action of shear force. The two-dimensional heat conduction path improves the efficiency of longitudinal heat diffusion, avoiding local overheating. During combustion, the heat migrates to the surface of the material in a directional manner to form a dense ceramic protective layer. The dense SiO2 shell blocks oxygen penetration, delays resin oxidation, and improves the thermal stability of the material.

[0017] The modified magnesium-aluminum double hydroxide of the present invention is modified by sodium dodecyl sulfate intercalation to expand the interlayer spacing. The grafted siloxane in the triazine thermal stabilizer is then hydrolyzed to form covalent bonds with the surface hydroxyl groups of the magnesium-aluminum double hydroxide, achieving both intercalation and surface modification. The sodium dodecyl sulfate intercalation increases the interlayer spacing of the magnesium-aluminum double hydroxide. The long-chain sodium dodecyl sulfate and triazine thermal stabilizer grafting together improve the interfacial bonding of the magnesium-aluminum double hydroxide to the polymer matrix. Once uniformly dispersed, it inhibits crack propagation and enhances interfacial shear strength. Upon thermal decomposition, the magnesium-aluminum double hydroxide releases H2O / CO2 to dilute oxygen, and the layers recombine to form an Al2O3 / MgO thermal insulation layer. The decomposition products of the triazine thermal stabilizer (containing N radicals) synergize with the P / N ratio of DOPO in the modified nanocore-shell particles, improving flame retardancy. Furthermore, the triazine structure captures free radicals, and the hindered phenol groups decompose peroxides, further enhancing the thermal stability of the material. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] Example 1 A modified nano core-shell particle is obtained by coating DOPO-loaded mesoporous microspheres with h-BN-doped polyurethane elastomer, wherein the mesoporous microspheres are nano-Fe3O4 coated with mesoporous silica. The preparation method thereof comprises the following steps: 2.0 g of hexadecyltrimethylammonium bromide was dissolved in 200 mL of deionized water, 2.0 g of nano-Fe3O4 was added to the hexadecyltrimethylammonium bromide solution, ultrasonically dispersed for 30 min, 100 mL of 10 mM NaOH solution was added, stirred evenly, and then 10 mL of 20 vol% ethyl orthosilicate ethanol solution was added. The mixture was stirred at 60 ° C for 18 h, centrifuged and washed, and then vacuum dried. Finally, it was calcined at 550 ° C for 5 h to obtain mesoporous silica-coated nano-Fe3O4 microspheres; B. 4.5 g of mesoporous silica-coated nano-Fe3O4 microspheres were dispersed in 200 mL of anhydrous ethanol, and then 0.9 g of 3-aminopropyltriethoxysilane was added. The mixture was refluxed at 80 ° C for 6 h, centrifuged and washed, and then vacuum-dried to obtain amino-modified mesoporous microspheres. The amino-modified mesoporous microspheres were immersed in 100 mL of 50 mg / mL 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide acetone solution, ultrasonicated for 1.5 h, and allowed to stand under -0.1 MPa vacuum for 10 h. After filtration, washing, and vacuum drying, DOPO-loaded mesoporous microspheres were obtained. C. Add 10 g of poly(hexamethylene adipate) and 20 g of isophorone diisocyanate into a reactor and heat to 80° C., react for 1.5 h under N2 protection, then add 2 g of 1,4-butanediol and 1 g of 2,2-dimethylolpropionic acid for chain extension, and continue the reaction for 3 h to obtain a polyurethane prepolymer; D. Disperse 5.5 g of hexagonal boron nitride in 100 mL of Tris-HCl buffer, add 1.8 g of dopamine hydrochloride, stir at room temperature for 18 h, and centrifuge to obtain polydopamine-coated hexagonal boron nitride. Disperse the polydopamine-coated hexagonal boron nitride in 100 mL of 90 vol% ethanol solution, add 1.1 g of 3-aminopropyltriethoxysilane, reflux at 80 ° C for 6 h, and centrifuge to obtain modified hexagonal boron nitride; E. 18 g of polyurethane prepolymer and 2 g of modified hexagonal boron nitride were added to 200 mL of acetone and ultrasonically dispersed to obtain an oil phase. 6.0 g of DOPO-loaded mesoporous microspheres were dispersed in 200 mL of polyvinyl alcohol solution and homogenized and emulsified to obtain an aqueous phase. The oil phase was added dropwise to the aqueous phase and mechanically stirred to form an O / W emulsion. The temperature was raised to 60°C to evaporate the acetone to obtain polyurethane-coated core-shell particles. Triethylamine and epichlorohydrin were added and reacted at 60°C for 4 h. The mixture was centrifuged, washed, and vacuum dried to obtain modified nano core-shell particles.

[0020] Example 2 A modified magnesium aluminum double hydroxide is prepared by modifying lamellar magnesium aluminum double hydroxide by intercalation with sodium dodecyl sulfate and then grafting a triazine heat stabilizer. The triazine heat stabilizer is a silane-modified hindered phenol heat stabilizer, and its chemical structure is as follows: ; The preparation method comprises the following steps: (1) Sodium dodecyl sulfate was dissolved in deionized water to obtain a 0.1-0.5 mol / L sodium dodecyl sulfate solution, 10 g of magnesium aluminum double hydroxide was added to 200 mL of the sodium dodecyl sulfate solution, and the mixture was stirred at 70 ° C for 18 h under nitrogen protection, centrifuged, washed with deionized water / ethanol 3-5 times, and dried in vacuo at 60 ° C to obtain intercalated modified magnesium aluminum double hydroxide; (2) 5.6 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and 10 mL of triethylamine were added to 90 mL of 1,4-dioxane and dissolved. After cooling in an ice bath, 3.2 g of 1,1'-carbonyldiimidazole was slowly added dropwise. The mixture was stirred and reacted for 50 min in an ice bath. 1.8 g of cyanuric chloride was dissolved in 20 mL of 1,4-dioxane and added dropwise to the reaction system. After reacting in an ice bath for 2 h, the temperature was slowly raised to 50 ° C and the reaction was continued for 4 h. Finally, 2.2 g of 3-aminopropyltriethoxysilane was added to the system. The temperature was raised to 75 ° C and the reaction was continued for 4 h. 100 mL of saturated NaHCO3 was added to quench the mixture. The organic phase was extracted with dichloromethane and dried with anhydrous magnesium sulfate. After rotary evaporation, the mixture was purified by column chromatography to obtain a triazine thermal stabilizer. (3) 10 g of the intercalated modified magnesium aluminum double hydroxide obtained in step (1) was added to 100 mL of 90 vol% ethanol solution and ultrasonically dispersed, and then 3 g of triazine thermal stabilizer was added. The mixture was ultrasonically treated for 30 min, heated to 55 ° C and reacted for 4 h, and filtered, washed, and dried to obtain the modified magnesium aluminum double hydroxide.

[0021] Example 3 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 70 parts of basalt fiber, 30 parts of bisphenol A epoxy resin, 15 parts of diaminodiphenylmethane, 5 parts of modified nano core-shell particles, 5 parts of modified magnesium aluminum double hydroxide, 3 parts of titanate coupling agent NDZ101, and 0.15 parts of 2,4,6-tris(dimethylaminomethyl)phenol; the modified nano core-shell particles are prepared in Example 1, and the modified magnesium aluminum double hydroxide is prepared in Example 2.

[0022] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin, modified nano core-shell particles, modified magnesium aluminum double hydroxide, and titanate coupling agent NDZ101 at 60°C for 1 h, add diaminodiphenylmethane and 2,4,6-tris(dimethylaminomethyl)phenol, and degas under -0.1 MPa vacuum for 15 min to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Then apply a 0.5T vertical magnetic field and heat-cure in stages: pre-cure at 80°C for 1 hour, then heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0023] Example 4 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 60 parts of basalt fiber, 40 parts of bisphenol A epoxy resin, 5 parts of diaminodiphenyl sulfone, 8 parts of modified nano core-shell particles, 3 parts of modified magnesium aluminum double hydroxide, 5 parts of silane coupling agent KH560, and 0.05 parts of 4-dimethylaminopyridine; the modified nano core-shell particles are prepared in Example 1, and the modified magnesium aluminum double hydroxide is prepared in Example 2.

[0024] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin with modified nano core-shell particles, modified magnesium aluminum double hydroxide, and silane coupling agent KH560 at 60°C for 2 h, add diaminodiphenyl sulfone and 4-dimethylaminopyridine, and degas under -0.1 MPa vacuum for 5 min to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Apply a 1T vertical magnetic field and heat-cure in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0025] Example 5 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 65 parts of basalt fiber, 35 parts of bisphenol A epoxy resin, 10 parts of methyltetrahydrophthalic anhydride, 6 parts of modified nano core-shell particles, 4 parts of modified magnesium aluminum double hydroxide, 4 parts of silane coupling agent KH550, and 0.1 part of 2-ethyl-4-methylimidazole; the modified nano core-shell particles are prepared in Example 1, and the modified magnesium aluminum double hydroxide is prepared in Example 2.

[0026] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin, modified nano core-shell particles, modified magnesium aluminum double hydroxide, and silane coupling agent KH550 at 60°C for 1.5 h, add methyltetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole, and degas under vacuum at -0.1 MPa for 10 min to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Then apply a 0.8T vertical magnetic field and heat-cure the mold in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0027] Comparative Example 1 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 65 parts of basalt fiber, 35 parts of bisphenol A epoxy resin, 10 parts of methyltetrahydrophthalic anhydride, 4 parts of modified magnesium aluminum double hydroxide, 4 parts of silane coupling agent KH550, and 0.1 part of 2-ethyl-4-methylimidazole; the modified magnesium aluminum double hydroxide is prepared in Example 2.

[0028] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin, modified magnesium aluminum double hydroxide, and silane coupling agent KH550 at 60°C for 1.5 h, add methyltetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole, and degas under -0.1 MPa vacuum for 10 min to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Then apply a 0.8T vertical magnetic field and heat-cure the mold in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0029] Comparative Example 2 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 65 parts of basalt fiber, 35 parts of bisphenol A epoxy resin, 10 parts of methyltetrahydrophthalic anhydride, 6 parts of modified nano core-shell particles, 4 parts of silane coupling agent KH550, and 0.1 part of 2-ethyl-4-methylimidazole; the modified nano core-shell particles are prepared in Example 1.

[0030] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin, modified nano core-shell particles, and silane coupling agent KH550 at 60°C for 1.5 h, add methyltetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole, and degas under -0.1 MPa vacuum for 10 min to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Then apply a 0.8T vertical magnetic field and heat-cure the mold in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0031] Comparative Example 3 A highly flame-retardant basalt fiber photovoltaic substrate comprises the following components in parts by weight: 65 parts of basalt fiber, 35 parts of bisphenol A epoxy resin, 10 parts of methyltetrahydrophthalic anhydride, 4 parts of silane coupling agent KH550, and 0.1 part of 2-ethyl-4-methylimidazole.

[0032] The method for preparing the highly flame-retardant basalt fiber photovoltaic substrate comprises the following steps: S1. Mechanically stir bisphenol A epoxy resin and silane coupling agent KH550 at 60°C for 1.5 hours, add methyltetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole, and degas under vacuum at -0.1 MPa for 10 minutes to obtain epoxy resin glue; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Then apply a 0.8T vertical magnetic field and heat-cure the mold in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

[0033] Performance testing The performance of the highly flame-retardant basalt fiber photovoltaic substrates in Examples 3 to 5 and Comparative Examples 1 to 3 was tested as follows: (1) Mechanical properties: The tensile strength test was carried out in accordance with GB / T 1040.1-2018, the bending strength test was carried out in accordance with GB / T 9341-2008, and the impact strength test was carried out in accordance with GB / T 1843-2008. The test results are shown in Table 1.

[0034] From the data in Table 1, it can be seen that the mechanical properties of the materials in Comparative Examples 1 and 2 have both declined, with the decline in mechanical properties being most significant in Comparative Example 3. This indicates that the modified nano core-shell particles and modified magnesium aluminum double hydroxide of the present invention can effectively improve the mechanical properties of the materials. The modified nano core-shell particles use magnetic nano Fe3O4 as the core, and are sequentially coated with mesoporous silica and a polyurethane soft shell. The mesoporous silica has a DOPO flame retardant adsorbed on it, and the polyurethane is uniformly dispersed with hexagonal boron nitride coated with polydopamine. The rigid support of the nano Fe3O4 and mesoporous silica hard cores suppresses plastic deformation of the matrix, while the elastic deformation of the polyurethane soft shell absorbs impact energy, enhancing impact strength through crack deflection and bridging effects. The high modulus h-BN is dispersed in the resin matrix, effectively transferring load and improving bending strength. The sodium dodecyl sulfate intercalation of the modified magnesium aluminum double hydroxide expands the interlayer spacing of the magnesium aluminum double hydroxide. The long-chain sodium dodecyl sulfate and triazine thermal stabilizer are grafted together to improve the interfacial binding ability of magnesium aluminum double hydroxide at the polymer matrix. After uniform dispersion, it hinders crack propagation and improves the interfacial shear strength.

[0035] (2) Flame retardant properties: The oxygen index test (LOI) was conducted in accordance with GB / T 2406.2-2009, and the horizontal and vertical (UL-94) burning test was conducted in accordance with GB / T2408-2021. The test results are shown in Table 2:

[0036] The data in Table 2 show that the flame retardancy of the materials in Comparative Examples 1 and 2 decreased, with the most significant decrease in Comparative Example 3. This demonstrates that both the modified nano-core-shell particles and the modified magnesium-aluminum double hydroxide of the present invention effectively improve the flame retardancy of the materials. The DOPO loaded in the modified nano-core-shell particles releases PO· radicals that capture H· / OH·, inhibiting the combustion chain reaction. The layered structure of h-BN promotes the formation of a dense carbon layer, and Fe3O4 catalyzes the graphitization of the carbon layer, enhancing the barrier effect and thus improving the flame retardancy of the material. In the modified magnesium-aluminum double hydroxide, the magnesium-aluminum double hydroxide itself decomposes upon heating to release H2O / CO2 to dilute the oxygen, and the layers recombine to form an Al2O3 / MgO insulation layer. The decomposition products of the triazine heat stabilizer (containing N radicals) synergize with the P / N ratio of DOPO in the modified nano-core-shell particles, improving flame retardancy.

[0037] (3) Antioxidation test: The samples were equilibrated at 23°C / 50% RH for 48 h, and then placed in a constant temperature oven (100°C±1°C) for accelerated aging. Samples were taken every 24 h, the tensile strength was tested, and the retention rate was calculated to obtain the data shown in Table 3 below.

[0038] The data in Table 3 show that the aging resistance of the materials in Comparative Examples 1 and 3 decreased significantly. After the modified nano-core-shell particles were added, the application of a perpendicular magnetic field induced the Fe3O4 cores to align in a directional manner. At the same time, the h-BN nanosheets were oriented along the magnetic field under the shear force. The two-dimensional heat conduction path improved the efficiency of longitudinal heat diffusion, avoiding local overheating. During combustion, the heat migrated to the surface of the material in a directional manner, forming a dense ceramic protective layer. The dense SiO2 shell blocked oxygen penetration, delayed resin oxidation, and improved the thermal stability of the material. The thermal stability of the material in Comparative Example 2 also decreased, mainly due to the grafting of triazine thermal stabilizers in the modified magnesium aluminum double hydroxide. The triazine structure captured free radicals, and the hindered phenol groups decomposed peroxides, further improving the thermal stability of the material.

[0039] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0040] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A highly flame-retardant basalt fiber photovoltaic substrate, characterized in that: The invention comprises the following components in parts by weight: 60-70 parts of basalt fiber, 30-40 parts of bisphenol A epoxy resin, 5-15 parts of curing agent, 5-8 parts of modified nano core-shell particles, 3-5 parts of modified magnesium aluminum double hydroxide, 3-5 parts of coupling agent, and 0.05-0.15 parts of accelerator; The modified nano core-shell particles are obtained by coating DOPO-loaded mesoporous microspheres with h-BN-doped polyurethane elastomer, and the mesoporous microspheres are nano Fe3O4 surfaces coated with mesoporous silica; The modified magnesium aluminum double hydroxide is a lamellar magnesium aluminum double hydroxide modified by sodium dodecyl sulfate intercalation and then grafted with a triazine heat stabilizer. The triazine heat stabilizer is a silane-modified hindered phenol heat stabilizer.

2. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 1, characterized in that: The curing agent is one of diaminodiphenylmethane, diaminodiphenyl sulfone and methyltetrahydrophthalic anhydride, the coupling agent is one of silane coupling agent KH550, silane coupling agent KH560, titanate coupling agent NDZ101 and aluminate coupling agent DL411, and the accelerator is one of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 4-dimethylaminopyridine and 2-ethyl-4-methylimidazole.

3. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 1, characterized in that: The preparation method of the modified nano core-shell particles comprises the following steps: A. Dissolve hexadecyltrimethylammonium bromide in deionized water, add nano-Fe3O4 to the hexadecyltrimethylammonium bromide solution, ultrasonically disperse for 20-40 minutes, add 10mM NaOH solution, stir evenly, then add ethyl orthosilicate ethanol solution, stir at 60℃ for 12-24 hours, centrifuge and wash, vacuum dry, and finally calcine at 550℃ for 4-6 hours to obtain mesoporous silica-coated nano-Fe3O4 microspheres; B. Dispersing the mesoporous silica-coated nano-Fe3O4 microspheres in anhydrous ethanol, adding 3-aminopropyltriethoxysilane, reflux at 80°C for 4-8 hours, centrifugally washing, and vacuum drying to obtain amino-modified mesoporous microspheres. The amino-modified mesoporous microspheres are immersed in an acetone solution of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically treated for 1-2 hours, and allowed to stand under -0.1 MPa vacuum for 8-12 hours. After filtration, washing, and vacuum drying, DOPO-loaded mesoporous microspheres are obtained. C. Add poly(hexamethylene adipate) and isophorone diisocyanate into a reactor and heat to 80°C. React for 1-2 hours under N2 protection. Then add 1,4-butanediol and 2,2-dimethylolpropionic acid to extend the chain. Continue to react for 2-4 hours to obtain a polyurethane prepolymer. D. Disperse hexagonal boron nitride in Tris-HCl buffer, add dopamine hydrochloride, stir at room temperature for 12-24 hours, and centrifuge to obtain polydopamine-coated hexagonal boron nitride. Disperse the polydopamine-coated hexagonal boron nitride in 90 vol% ethanol solution, add 3-aminopropyltriethoxysilane, reflux at 80°C for 4-8 hours, and centrifuge to obtain modified hexagonal boron nitride. E. Polyurethane prepolymer and modified hexagonal boron nitride were added to acetone in a mass ratio of 8-10:1 and ultrasonically dispersed to obtain an oil phase. DOPO-loaded mesoporous microspheres were dispersed in a polyvinyl alcohol solution and homogenized to obtain an aqueous phase. The oil phase was added dropwise to the aqueous phase and mechanically stirred to form an O / W emulsion. The temperature was raised to 60°C to evaporate the acetone to obtain polyurethane-coated core-shell particles. Triethylamine and epichlorohydrin were added and reacted at 60°C for 3-5 hours. The mixture was centrifuged, washed, and vacuum dried to obtain modified nano core-shell particles.

4. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 3, characterized in that: In step A, the mass ratio of nano-Fe3O4, hexadecyltrimethylammonium bromide and ethyl orthosilicate is 1:1:2-4.

5. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 3, characterized in that: In the step B, the mass ratio of the mesoporous silica-coated nano-Fe3O4 microspheres, 3-aminopropyltriethoxysilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:0.2:0.5-1.

5.

6. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 3, characterized in that: In the step C, the mass ratio of poly(hexamethylene adipate), isophorone diisocyanate, 1,4-butanediol and 2,2-dimethylolpropionic acid is 1:1.8-2.2:0.2:0.

1.

7. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 3, characterized in that: In the step D, the mass ratio of hexagonal boron nitride, dopamine hydrochloride and 3-aminopropyltriethoxysilane is 1:0.2 to 0.5:0.

2.

8. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 1, characterized in that: The preparation method of the modified magnesium aluminum double hydroxide comprises the following steps: (1) Sodium dodecyl sulfate was dissolved in deionized water to obtain a 0.1-0.5 mol / L sodium dodecyl sulfate solution, magnesium aluminum double hydroxide was added to the sodium dodecyl sulfate solution, stirred at 60-80°C for 12-24 hours under nitrogen protection, centrifuged, washed with deionized water / ethanol 3-5 times, and dried in vacuo at 60°C to obtain intercalated modified magnesium aluminum double hydroxide; (2) 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and triethylamine were dissolved in 1,4-dioxane, and 1,1'-carbonyldiimidazole was slowly added dropwise after cooling in an ice bath. The mixture was stirred and reacted for 40-60 minutes in an ice bath. Cyanuric chloride was dissolved in 1,4-dioxane and added dropwise to the reaction system. The mixture was reacted in an ice bath for 1-2 hours, and then the temperature was slowly raised to 40-50°C. The reaction was continued for 3-4 hours. Finally, 3-aminopropyltriethoxysilane was added to the system, and the temperature was raised to 70-80°C for 3-4 hours. Saturated NaHCO3 was added to quench the mixture. The organic phase was extracted with dichloromethane, dried with anhydrous magnesium sulfate, and purified by column chromatography after rotary evaporation to obtain a triazine thermal stabilizer. (3) The intercalated modified magnesium aluminum double hydroxide obtained in step (1) is added to an ethanol solution for ultrasonic dispersion, and then a triazine thermal stabilizer is added, ultrasonically treated for 20 to 40 minutes, heated to 50 to 60° C. for reaction for 3 to 5 hours, filtered, washed, and dried to obtain the modified magnesium aluminum double hydroxide.

9. The highly flame-retardant basalt fiber photovoltaic substrate according to claim 8, characterized in that: The molar ratio of the 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 1,1'-carbonyldiimidazole, cyanuric chloride and KH-550 is 2:2:1:1, and the mass ratio of the intercalated modified magnesium aluminum double hydroxide and the triazine heat stabilizer is 1:0.2-0.

4.

10. The method for preparing a highly flame-retardant basalt fiber photovoltaic substrate according to any one of claims 1 to 9, characterized in that: The following steps are included: S1. Mechanically stir bisphenol A epoxy resin, modified nano core-shell particles, modified magnesium aluminum double hydroxide, and a coupling agent at 60° C. for 1 to 2 hours, add a curing agent and an accelerator, and perform vacuum degassing at -0.1 MPa for 5 to 15 minutes to obtain an epoxy resin adhesive; S2. Lay basalt fibers in a mold to the desired thickness, then pour epoxy resin into the mold until the fibers are just covered. Apply a vertical magnetic field of 0.5 to 1 T, and heat and cure in stages: pre-cure at 80°C for 1 hour, heat to 150°C for 2 hours, and finally heat to 180°C for 1 hour. S3. The cured composite material is molded at 10 MPa, and then cooled to 60° C. and demolded to obtain the highly flame-retardant basalt fiber photovoltaic substrate.

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