Energy storage luminescent nano-coating material and preparation method thereof

Abstract

The present application relates to the technical field of energy storage luminescent paint, in particular to a kind of energy storage luminescent nano coating material and preparation method thereof;The application is synthesized with the composite luminescent powder of three-layer structure of luminescent core, transition layer and shell, wherein the core provides basic luminescent performance, the transition layer reduces interface defects and promotes electron transfer through lattice matching, and the shell optimizes luminescent efficiency and afterglow characteristics;At the same time, the light absorption range is expanded by modified GQDs, the coating density is enhanced by modified nano SiO2, and the dispersion stability is improved by modified bentonite, and the synergistic effect of each component is realized by step ball milling, calcination and other processes, forming a coating material with high efficiency luminescence and excellent weather resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage luminescent coating, in particular to an energy storage luminescent nano coating material and a preparation method thereof. BACKGROUND

[0002] Energy storage luminescent coating material is a kind of functional material that can absorb and store light energy and release visible light in the dark environment. Its core value lies in realizing long-acting luminescence without energy dependence, and it is widely used in safety warning, emergency guidance, environmental beautification and intelligent interaction fields. In the safety protection scene, this kind of coating can be used for fire exit identification, tunnel escape guidance and industrial equipment warning, and can provide reliable light source in power failure or smoke environment by using long afterglow characteristics. In the field of building and decoration, its self-luminescent property can replace night lighting, and at the same time realize the dynamic aesthetic effect of building appearance. The existing energy storage luminescent coating materials are mainly divided into three categories: first, silicate and nitride system, which is suitable for aerospace and industrial high-temperature equipment identification, but has the characteristics of low initial luminescent intensity and fast afterglow decay. Second, non-doped metal halide system, which can realize long afterglow luminescence without rare earth doping, but the system contains heavy metals, which does not meet the environmental protection standard, and the mechanical strength is poor and easy to peel off, and the luminescent wavelength has weak penetration in the smoke environment. Third, rare earth activated aluminate system, which has high initial luminescent intensity and long afterglow time, and is widely used in traffic signs, fire equipment and building curtain walls, but its resistance to strong acid and strong alkali is poor and it is easy to degrade in specific chemical environment. SUMMARY

[0003] In view of the shortcomings of the prior art, the present application provides an energy storage luminescent nano coating material and a preparation method thereof. A composite luminescent powder with three-layer structure of luminescent core, transition layer and shell is designed and synthesized, wherein the core provides basic luminescent performance, the transition layer reduces interface defects and promotes electron transfer through lattice matching, and the shell optimizes luminescent efficiency and afterglow characteristics; at the same time, modified GQDs are combined to expand the light absorption range, modified nano SiO2 is combined to enhance the coating density, and modified bentonite is combined to improve the dispersion stability, so as to realize the synergistic effect of each component through step-by-step ball milling and calcination process, and form a coating material with high-efficiency luminescence and excellent weather resistance.

[0004] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] In a first aspect, the present application provides an energy storage luminescent nano coating material, which comprises modified nano SiO2, silicone-acrylate emulsion, polycarboxylate dispersant, composite luminescent powder and modified bentonite in a mass ratio of (1.8-2):100:1.8:(28-32):(0.5-0.7).

[0006] The composite luminescent powder is obtained by reaction of luminescent powder precursor, modified GQDs, tetraethyl orthosilicate and methyltrimethoxysilane.

[0007] The luminescent powder precursor is obtained by calcining a luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3 and Li2CO3 in a mixed atmosphere at a mass ratio of 100:(14-16):(40-42):(1.5-2):(1-1.3):(0.06-0.08); the luminescent intermediate material is obtained by calcining a luminescent inner core material with SrCO3 and Al2O3 in a mixed atmosphere at a mass ratio of (19-21):3:6; the luminescent inner core material is obtained by calcining SrCO3, Al2O3 and Eu2O3 in a mixed atmosphere at a molar ratio of 1:(1-1.02):0.002;

[0008] The mixed atmosphere comprises a reducing gas and an inert gas;

[0009] The modified GQDs are obtained by modifying GQDs with 3-mercaptopropyltrimethoxysilane;

[0010] The modified nano-SiO2 is obtained by modifying nano-SiO2 with a first silane coupling agent;

[0011] The modified bentonite is obtained by modifying bentonite with a second silane coupling agent.

[0012] In a feasible implementation scenario, the luminescent powder precursor is dispersed in anhydrous ethanol to obtain a luminescent powder precursor dispersion, the modified GQDs are dispersed in anhydrous ethanol to obtain a modified GQDs dispersion, and the volume ratio of the modified GQDs dispersion, the luminescent powder precursor dispersion, tetraethyl orthosilicate and methyltrimethoxysilane is (1-1.2):50:4:0.25; the volume percentage of the reducing gas in the mixed atmosphere is 5%, the reducing gas is hydrogen, and the inert gas is one of nitrogen and argon; the first silane coupling agent and the second silane coupling agent are both KH-570.

[0013] In a feasible implementation scenario, the polycarboxylate dispersant is a sodium polycarboxylate dispersant with a solid content of 43% to 45%; the bentonite contains montmorillonite at a content of ≥95% and has a bentonite particle size D50≤30 μm; the GQDs have a size of 5-10 nm; the silicone-acrylate emulsion is an acrylate-silicone emulsion with a solid content of 38% to 40%, a viscosity of 90-110 mPa・s, a particle size of 80-100 nm and a pH of 7-8; the nano-SiO2 has a particle size of 10-30 nm; and the SrCO3 and Al2O3 have a particle size <1 μm.

[0014] In a second aspect, the application provides a preparation method of an energy storage luminescent nano coating material, comprising the following steps:

[0015] S1, mixing SrCO3, Al2O3 and Eu2O3, after first ball milling treatment, first calcination in mixed atmosphere, to obtain a luminescent core material; mixing the luminescent core material, SrCO3 and Al2O3, after second ball milling treatment, second calcination in mixed atmosphere, to obtain a luminescent intermediate material; mixing the luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3 and Li2CO3, after third ball milling treatment, third calcination in mixed atmosphere, to obtain a luminescent powder precursor;

[0016] S2, adding 3-mercaptopropyl trimethoxysilane to the GQDs dispersion, first heating reaction, to obtain modified GQDs; dispersing the modified GQDs in anhydrous ethanol to obtain a modified GQDs dispersion; dispersing the luminescent powder precursor in anhydrous ethanol to obtain a luminescent powder precursor dispersion; mixing the modified GQDs dispersion and the luminescent powder precursor dispersion, adding tetraethyl orthosilicate and methyl trimethoxysilane, adjusting to a set pH, room temperature reaction to obtain a composite luminescent powder;

[0017] S3, dispersing nano-SiO2 in anhydrous ethanol to obtain a nano-SiO2 dispersion, adding a first silane coupling agent to the nano-SiO2 dispersion, second heating reaction to obtain modified nano-SiO2; preparing a silane hydrolysis solution with a second silane coupling agent, mixing bentonite with anhydrous ethanol to prepare a bentonite slurry, heating to a set temperature, adding the silane hydrolysis solution dropwise to the bentonite slurry, holding to react to obtain modified bentonite;

[0018] S4, dispersing the modified nano-SiO2 in a silicone-acrylate emulsion at a set stirring speed, keeping the stirring speed, adding polycarboxylate dispersant, composite luminescent powder and modified bentonite in turn every set time, to obtain the energy storage luminescent nano-coating material.

[0019] In a feasible implementation scenario, the rotation speed of the first ball milling treatment is 300-400 rpm, and the time is 2-3 h; the rotation speed of the second ball milling treatment is 300-400 rpm, and the time is 1-1.5 h; the rotation speed of the third ball milling treatment is 350-450 rpm, and the time is 2-2.5 h; before the first ball milling treatment, the second ball milling treatment and the third ball milling treatment, the same amount of anhydrous ethanol as the solid material is added.

[0020] In a feasible implementation scenario, the temperature of the first calcination is 1200-1250℃, and the time is 3-3.5 h; the temperature of the second calcination is 1100-1150℃, and the time is 2-3 h; the temperature of the third calcination is 1150-1200℃, and the time is 2-3 h.

[0021] Ethanol as a dispersion medium can reduce the surface energy of inorganic powder (SrCO3, Al2O3, etc.), avoid agglomeration, and ensure uniform mixing of raw materials. In the first calcination stage, SrCO3 is decomposed into SrO at high temperature, and then reacts with Al2O3 to form SrAl2O3; Eu2O3 is reduced to EuO under H2 reduction atmosphere, and Eu 2+ is similar to Sr 2+ , replaces Sr 2+ into the SrAl2O4 lattice to form SrAl2O4:Eu 2+ core, forming a luminescent center, Eu 2+ is a luminescent active ion, providing luminescent performance; the reducing atmosphere avoids Eu 2+ oxidation into non-luminescent Eu 3+ . In the second calcination stage, the luminescent core material continues to be calcined with SrCO3 and Al2O3, SrCO3 is decomposed into SrO at high temperature, and reacts with Al2O3 and the SrAl2O4 on the surface of the core to form SrAl3O6, forming a "SrAl2O4@SrAl3O6" transition layer structure, reducing the interface defects such as dislocations and cracks between the core and the subsequent shell through lattice matching, providing a channel for the transfer of electrons from the core to the shell, and reducing non-radiative transition loss. In the third calcination stage, SrCO3 is decomposed into SrO at high temperature, and reacts with Al2O3 and the SrAl3O6 on the surface of the intermediate to form a SrAl4O7 shell; Dy 3+ (release ≈ 91 pm) replaces Sr 2+ into the lattice to form an electron trap that can capture Eu 2+ excited state electrons, store electrons to prolong afterglow, Li + (release ≈ 76 pm) doped to fine-tune lattice distortion, optimize Dy 3+ trap depth, improve the binding ability of the trap to electrons, and overall improve the afterglow time.

[0022] In a feasible implementation scenario, the concentration of the GQDs dispersion liquid is 1wt%-1.2wt%; the amount of 3-mercaptopropyltrimethoxysilane is 0.08%-0.12% of the GQDs dispersion liquid, the concentration of the modified GQDs dispersion liquid is 0.5wt%-0.8wt%; the concentration of the luminescent powder precursor dispersion liquid is 10wt%-12wt%, the temperature of the first heating reaction is 60-65℃, and the time is 2-3h; the set pH is 9, and the room temperature reaction time is 2-3h.

[0023] GQDs dispersion liquid is added with 3-mercaptopropyl trimethoxysilane (MPTMS), the mercapto group (-SH) of MPTMS is covalently combined with the surface hydroxyl group (-OH) or carboxyl group (-COOH) of GQDs, and meanwhile, the silicon-oxygen group [-Si(OCH3)3] of MPTMS is hydrolyzed to generate a silicon hydroxyl group (-Si-OH), so as to realize the surface functionalization of GQDs; the modified GQDs are combined with SiO2 through the silicon hydroxyl group, so as to improve the dispersion stability; the GQDs retain wide spectrum absorption and expand the light excitation range.

[0024] The modified GQDs dispersion liquid is mixed with a luminescent powder precursor dispersion liquid, tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS) are added, TEOS is hydrolyzed to generate SiO2 sol under alkaline conditions, and is condensed with the surface silicon hydroxyl group of GQDs (-Si-OH+HO-Si-→-Si-O-Si-+H2O), so as to form a composite coating layer of SiO2-GQDs, MTMS contains a methyl group, and partially replaces TEOS, so as to reduce the hydrophilicity of the coating layer and improve the water resistance. The coating layer protects the inner core of the luminescent powder from water vapor erosion, the GQDs enhance the absorption of different light sources, and the saturation time of light irradiation is shortened; the SiO2 layer improves the compatibility of the luminescent powder with an organic base material.

[0025] In a feasible implementation scenario, the concentration of the nano-SiO2 dispersion liquid is 8wt%-10wt%, the amount of the first silane coupling agent is 10%-12% of the mass of the nano-SiO2; the temperature of the second heating reaction is 65-75℃, and the time is 1-2h; the set temperature is 60-65℃, the dropping speed is 1-3mL / min; the time of the heat preservation reaction is 2-3h; and the volume ratio of the bentonite slurry to the silane hydrolysis liquid is (3.8-4):1.

[0026] KH-570 is added to the nano-SiO2 dispersion liquid, the KH-570 is hydrolyzed to generate -Si-OH, which is condensed with the -OH on the surface of the nano-SiO2, and the acrylate group (-C=C-) is grafted, the compatibility of the modified nano-SiO2 with the silicone-acrylic emulsion (containing an acrylate segment) is improved, the nano-SiO2 is uniformly dispersed to fill the micro defects of the coating layer, the compactness is enhanced, and the water resistance is improved.

[0027] In a feasible implementation scenario, the preparation step of the silane hydrolysis liquid is specifically as follows: the second silane coupling agent, anhydrous ethanol and deionized water are mixed at a ratio of 6-8:100:10, hydrochloric acid is used to adjust the pH to 4-5, and stirring is performed for 20-30min to obtain the silane hydrolysis liquid.

[0028] The -Si-OH generated by the hydrolysis of KH-570 condenses with the -OH on the surface of bentonite, grafting organic groups, making bentonite change from hydrophilic to organic-philic. The modified bentonite forms a three-dimensional network structure in the silicone-acrylic emulsion, improving the thixotropy (anti-settling) and workability (leveling) of the coating, and inhibiting the settling of composite luminescent powder.

[0029] In one feasible implementation, the set stirring speed is 1500-1600 rpm, and the set time is 15-30 min.

[0030] Polycarboxylate dispersants (containing -COO) - The composite luminescent powder and nano-SiO2 particles are stabilized by electrostatic repulsion. The three-dimensional network of modified bentonite and the filling effect of nano-SiO2 work synergistically to balance the coating viscosity. The acrylate segments of the silicone-acrylic emulsion have good compatibility with the organic groups of modified nano-SiO2 and bentonite, forming a continuous film phase. All components are uniformly dispersed, and the coating has suitable application viscosity and stability. After film formation, it exhibits both high-efficiency luminescence performance and excellent weather resistance.

[0031] Beneficial technical effects:

[0032] This application describes the design and synthesis of a composite luminescent powder with a luminescent core, a transition layer, and a shell layer. This powder is then used in conjunction with a polycarboxylate dispersant, modified nano-SiO2, and modified bentonite to prepare an energy-storing luminescent nano-coating material exhibiting high luminescence performance and excellent weather resistance. The core layer is prepared using SrAl2O4:Eu 2+ Dy 3+ Long-afterglow luminescent powders are used to provide luminescent properties, utilizing Eu 2+ The transition of Dy produces visible light. 3+ As a trap energy level, it extends the afterglow; the transition layer is formed by ball milling and mixing raw materials such as SrCO3 and Al2O3 and then calcining to form a dense SrAl3O6 coating layer, which not only protects the core luminescent center from external erosion, but also reduces the non-radiative transition of luminescent ions through lattice matching, thus synergistically improving the luminescence efficiency with the luminescent core; the outer shell is SrAl4O7:Eu 2+ ,Dy 3+ Li + Eu 2+ Gradient doping reduces the probability of aggregation quenching and improves luminescence utilization. 3+ As a trap level that traps electrons and prolongs the afterglow, Li +The trap depth is optimized by lattice fine-tuning, and the energy storage and release channels matched with the energy level of the light-emitting core and the transition layer are formed. The synergistic effect of the three-layer structure not only improves the efficiency and durability of the light-emitting performance, but also protects the light-emitting core from water vapor, oxygen and other external factors through the physical barrier of the transition layer and the dense coating of the shell. After the modified bentonite is treated by silane hydrolysis solution, the three-dimensional network is constructed in the coating by forming covalent bonds between the silanol groups of the sheet structure and the surface of the luminescent powder and the molecular chains of the acrylate-silicone emulsion. Through the mutual promotion of each link, the luminescent performance and weather resistance of the energy storage and light-emitting nano coating material are synergistically enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The figure is a schematic diagram of the preparation method of the energy storage and light-emitting nano coating material in the present application.

[0034] Figure 2 The figure is a real object diagram of the energy storage and light-emitting nano coating material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in conjunction with examples. However, this should not be understood as limiting the scope of the present application to the following examples. All other examples obtained by those of ordinary skill in the art without making creative efforts under the premise of not departing from the method idea of the present application belong to the scope of protection of the present application.

[0036] In the present application, the terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application.

[0037] In the present application, the singular forms "is", "or", "a", "any" and "the" are intended to include the plural forms, unless the context clearly indicates otherwise.

[0038] In addition, if the terms "first", "second" appear, they are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0039] In the bentonite used in the embodiments of the present application, the montmorillonite content is ≥95%, the bentonite particle size D50 is ≤30μm; the particle size of nano-SiO2 is 10-30nm; the particle size of SrCO3 and Al2O3 is <1μm; the size of graphene quantum dots (GQDs) is 5-10nm, which is water-soluble; the solid content of silicone-acrylate emulsion is 38%-40%, the viscosity is 90-110mPa・s, the particle size is 80-100nm, and the pH is 7-8.

[0040] The following will specifically describe a kind of energy storage luminescent nano coating material and its preparation method provided by the application in combination with different embodiments.

[0041] Example 1

[0042] As shown in the figure, a preparation method of an energy storage luminescent nano coating material includes the following steps: Figure 1

[0043] 1. Take SrCO3, Al2O3 and Eu2O3 with a molar ratio of 1:1.01:0.002, add anhydrous ethanol with the same mass as the solid material, ball mill at 350 rpm for 2.5 h, dry and grind through a 200-mesh sieve, place in a tube furnace, pass in a H2 / Ar mixed atmosphere containing 5% by volume H2, calcine at 1200°C for 3 h, and naturally cool to room temperature to obtain a luminescent inner core material; mix the luminescent inner core material, SrCO3 and Al2O3 uniformly in a mass ratio of 20:3:6, add anhydrous ethanol with the same mass as the solid material, place in a tube furnace after ball milling at 350 rpm for 1 h, pass in a H2 / Ar mixed atmosphere containing 5% by volume H2, calcine at 1150°C for 2 h to obtain a luminescent intermediate material; mix the luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3 and Li2CO3 in a mass ratio of 100:15:41:1.8:1.2:0.07, add anhydrous ethanol with the same mass as the solid material, place in a tube furnace after ball milling at 400 rpm for 2 h, pass in a H2 / Ar mixed atmosphere containing 5% by volume H2, calcine at 1200°C for 2.5 h, and sieve through a 300-mesh sieve to obtain a luminescent powder precursor;

[0044] 2. Ultrasonically disperse the GQDs in deionized water to obtain a 1.1wt% GQDs dispersion; add 3-mercaptopropyltrimethoxysilane with a mass of 0.1% of the GQDs dispersion to the GQDs dispersion, react at 65°C for 2.5 h, and obtain modified GQDs after centrifugal washing; disperse the modified GQDs in anhydrous ethanol to obtain a 0.7wt% modified GQDs dispersion; ultrasonically disperse the luminescent powder precursor in anhydrous ethanol to obtain a 11wt% luminescent powder precursor dispersion; mix the modified GQDs dispersion and the luminescent powder precursor dispersion, add tetraethyl orthosilicate and methyltrimethoxysilane, and the volume ratio of the modified GQDs dispersion, the luminescent powder dispersion, the tetraethyl orthosilicate and the methyltrimethoxysilane is 1.1:50:4:0.25; after mixing, adjust the pH to 9, react at room temperature for 2.5 h, filter and dry to obtain a composite luminescent powder;

[0045] ​3. Ultrasonic dispersion of nano-SiO2 in anhydrous ethanol to obtain a 9wt% nano-SiO2 dispersion, addition of 11wt% KH-570 to the nano-SiO2, reaction at 70℃ for 1.5h, centrifugation, washing, and drying to obtain modified nano-SiO2; mixing of KH-570, anhydrous ethanol, and deionized water at 7:100:10, adjustment of pH to 4.5 with hydrochloric acid, stirring for 25min to obtain a silane hydrolysis solution, mixing of bentonite and anhydrous ethanol at equal mass, stirring to obtain a bentonite slurry, heating of the bentonite slurry to 65℃, dropwise addition of the silane hydrolysis solution at a rate of 2mL / min, volume ratio of the bentonite slurry to the silane hydrolysis solution being 3.9:1, post-heating reaction for 2.5h after completion of the dropwise addition, and drying after filtration and washing to obtain modified bentonite through a 400 mesh sieve;

[0046] 4. Dispersion of the modified nano-SiO2 in a silicone-acrylate emulsion at 1550rpm, maintenance of the stirring speed, and addition of polycarboxylate dispersant, composite luminescent powder, and modified bentonite every 20min, mass ratio of the modified nano-SiO2, silicone-acrylate emulsion, polycarboxylate dispersant, composite luminescent powder, and modified bentonite being 1.9:100:1.8:30:0.6, to obtain a storage energy and luminescent nano-coating material as shown in Figure 2 .

[0047] Example 2

[0048] As shown in Figure 1 , a method for preparing a storage energy and luminescent nano-coating material, comprising the following steps:

[0049] 1. Taking SrCO3, Al2O3, and Eu2O3 as raw materials at a molar ratio of 1:1:0.002, adding anhydrous ethanol at the same mass as the solid material, ball milling at 300rpm for 3h, drying and grinding through a 200 mesh sieve, placing in a tube furnace, passing in a H2 / Ar mixed gas atmosphere containing 5% by volume H2, calcining at 1200℃ for 3.5h, and naturally cooling to room temperature to obtain a luminescent core material; mixing the luminescent core material, SrCO3, and Al2O3 at a mass ratio of 19:3:6, adding anhydrous ethanol at the same mass as the solid material, ball milling at 300rpm for 1.5h, and then placing in a tube furnace, passing in a H2 / Ar mixed gas atmosphere containing 5% by volume H2, calcining at 1100℃ for 3h to obtain a luminescent intermediate material; mixing the luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3, and Li2CO3 at a mass ratio of 100:14:42:1.5:1.3:0.06, adding anhydrous ethanol at the same mass as the solid material, ball milling at 350rpm for 2.5h, and then placing in a tube furnace, passing in a H2 / Ar mixed gas atmosphere containing 5% by volume H2, calcining at 1150℃ for 3h, and sieving through a 300 mesh sieve to obtain a luminescent powder precursor;

[0050] 2. ultrasonic dispersion of GQDs in deionized water to obtain a 1wt% GQDs dispersion; adding 3-mercaptopropyltrimethoxysilane with a mass of 0.08% of the GQDs dispersion to the GQDs dispersion, reacting at 60℃ for 3h, centrifuging and washing to obtain modified GQDs; dispersing the modified GQDs in anhydrous ethanol to obtain a 0.5wt% modified GQDs dispersion; ultrasonic dispersion of the luminescent powder precursor in anhydrous ethanol to obtain a 10wt% luminescent powder precursor dispersion, mixing the modified GQDs dispersion and the luminescent powder precursor dispersion, adding tetraethyl orthosilicate and methyltrimethoxysilane, the volume ratio of the modified GQDs dispersion, the luminescent powder dispersion, tetraethyl orthosilicate and methyltrimethoxysilane being 1:50:4:0.25, adjusting the pH to 9 after mixing, stirring at room temperature for 2h, filtering and drying to obtain a composite luminescent powder;

[0051] 3. ultrasonic dispersion of nano-SiO2 in anhydrous ethanol to obtain an 8wt% nano-SiO2 dispersion, adding KH-570 with a mass of 10% of the nano-SiO2, water bath at 65℃ for 2h, centrifuging, washing and drying to obtain modified nano-SiO2; mixing KH-570, anhydrous ethanol and deionized water at a ratio of 6:100:10, adjusting the pH to 4 with hydrochloric acid, stirring for 20min to obtain a silane hydrolysis solution, mixing the bentonite and anhydrous ethanol in equal mass and stirring uniformly to obtain a bentonite slurry, heating the bentonite slurry to 60℃, adding the silane hydrolysis solution at a drop rate of 1mL / min, the volume ratio of the bentonite slurry and the silane hydrolysis solution being 3.8:1, maintaining the reaction for 2h after the addition is completed, and then filtering, washing and drying and passing through a 400 mesh sieve to obtain modified bentonite;

[0052] 4. dispersing the modified nano-SiO2 in a silicone-acrylate emulsion at 1500rpm, maintaining the stirring speed, and then sequentially adding polycarboxylate dispersant, composite luminescent powder and modified bentonite every 15min, the mass ratio of the modified nano-SiO2, the silicone-acrylate emulsion, the polycarboxylate dispersant, the composite luminescent powder and the modified bentonite being 1.8:100:1.8:32:0.5, to obtain an energy storage and luminescent nano-coating material.

[0053] Example 3

[0054] As shown in Figure 1 , a method for preparing an energy storage and luminescent nano-coating material, comprising the following steps:

[0055] 1. Take the raw material molar ratio of SrCO3, Al2O3 and Eu2O3 is 1:1.02:0.002, add the same mass of anhydrous ethanol as the solid material, ball mill at 400 rpm for 2 h, dry and grind through a 200 mesh sieve, place in a tube furnace, pass through a mixed gas atmosphere containing 5% by volume H2, calcine at 1250℃ for 3 h, and naturally cool to room temperature to obtain a luminescent core material; mix the luminescent core material, SrCO3 and Al2O3 in a mass ratio of 21:3:6, add the same mass of anhydrous ethanol as the solid material, place in a tube furnace after ball milling at 400 rpm for 1 h, pass through a mixed gas atmosphere containing 5% by volume H2, calcine at 1150℃ for 2 h to obtain a luminescent intermediate material; mix the luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3 and Li2CO3 in a mass ratio of 100:16:40:2:1:0.08, add the same mass of anhydrous ethanol as the solid material, place in a tube furnace after ball milling at 450 rpm for 2 h, pass through a mixed gas atmosphere containing 5% by volume H2, calcine at 1200℃ for 2 h, and sieve through a 300 mesh sieve to obtain a luminescent powder precursor;

[0056] 2. Ultrasonic dispersion of GQDs in deionized water to obtain a 1.2wt% GQDs dispersion; add 3-mercaptopropyltrimethoxysilane to the GQDs dispersion with a mass of 0.12% of the GQDs dispersion, react at 65℃ for 2 h, centrifuge and wash to obtain modified GQDs; disperse the modified GQDs in anhydrous ethanol to obtain a 0.8wt% modified GQDs dispersion; ultrasonic dispersion of the luminescent powder precursor in anhydrous ethanol to obtain a 12wt% luminescent powder precursor dispersion, mix the modified GQDs dispersion and the luminescent powder precursor dispersion, add tetraethyl orthosilicate and methyltrimethoxysilane, the volume ratio of the modified GQDs dispersion, the luminescent powder dispersion, tetraethyl orthosilicate and methyltrimethoxysilane is 1.2:50:4:0.25, after mixing, adjust the pH to 9, stir at room temperature for 3 h, filter and dry to obtain a composite luminescent powder;

[0057] 3. Ultrasonic dispersion of nano-SiO2 in anhydrous ethanol to obtain a 10wt% nano-SiO2 dispersion, add KH-570 with a mass of 12% of the nano-SiO2, water bath at 75℃ for 1 h, centrifuge, wash and dry to obtain modified nano-SiO2; mix KH-570, anhydrous ethanol and deionized water in a ratio of 8:100:10, adjust the pH to 5 with hydrochloric acid and stir for 30 min to obtain a silane hydrolysis solution, mix the bentonite with anhydrous ethanol in equal mass and stir uniformly to obtain a bentonite slurry, heat the bentonite slurry to 65℃, add the silane hydrolysis solution at a drop rate of 3mL / min, the volume ratio of the bentonite slurry and the silane hydrolysis solution is 4:1, after the addition is completed, heat and react for 3 h, filter, wash and dry, and sieve through a 400 mesh sieve to obtain modified bentonite;

[0058] 4. After dispersing the modified nano-SiO2 in the silicone-acrylate emulsion at 1600 rpm, keep the stirring speed, and then add the polycarboxylate dispersant, the composite luminescent powder and the modified bentonite in turn every 30 min. The mass ratio of the modified nano-SiO2, the silicone-acrylate emulsion, the polycarboxylate dispersant, the composite luminescent powder and the modified bentonite is 2:100:1.8:28:0.7, to obtain the energy storage luminescent nano coating material.

[0059] Comparative Example 1

[0060] A preparation method of an energy storage luminescent nano coating material, the preparation steps, parameters and example 1 are the same, the difference is that all the SrCO3, Al2O3, Eu2O3, Dy2O3 and Li2CO3 used in example 1 are mixed and ball milled at one time, and calcined at 1200℃ for 7.5h.

[0061] Comparative Example 2

[0062] A preparation method of an energy storage luminescent nano coating material, the preparation steps, parameters and example 1 are the same, the difference is that no modified nano-SiO2 is added.

[0063] Comparative Example 3

[0064] A preparation method of an energy storage luminescent nano coating material, the preparation steps, parameters and example 1 are the same, the difference is that no modified GQDs is added.

[0065] Performance test:

[0066] Viscosity: The viscosity of the energy storage luminescent nano coating materials prepared in example 1 to example 3 and comparative example 1 to comparative example 3 of the present application was tested by a rotary viscometer, and the results are shown in table 1.

[0067] Tack-free time: The energy storage luminescent nano coating materials prepared in example 1 to example 3 and comparative example 1 to comparative example 3 of the present application were evenly brushed on tinplate panels (150mm×70mm×0.3mm), the coating thickness was controlled to be 100±10μm, and then placed in a constant temperature and humidity environment (temperature 25℃, relative humidity 50%), every 10 min, the coating surface was touched with a clean finger, the contact time was 1-2 seconds, whether the paint was sticky on the finger was observed, and whether there was obvious trace on the coating surface (no depression, no fingerprint residue) was observed, when the first time "the finger was not sticky with paint, and the coating surface only left a slight fingerprint and could quickly recover", the time was recorded, which was the tack-free time, and the results are shown in table 1.

[0068] Alkali resistance: The energy storage and luminescent nano coating material prepared in the examples and comparative examples of the present application was brushed on a cement asbestos board (100 mm x 100 mm x 5 mm, cured for 28 days according to the standard requirements) with a wet film thickness of 100 ± 10 μm, and dried at room temperature for 7 days to obtain a test plate coating. A 0.1 mol / L NaOH solution was prepared and placed in a glass tank, and the temperature was controlled at 23 ± 2°C. The test plate coating was immersed horizontally in the NaOH solution (the liquid surface was 5 mm higher than the coating surface), ensuring that the test plate did not contact the tank wall, and was soaked for 96 h (the water loss was replenished during the soaking process to maintain a stable concentration). The test plate was removed, the surface was rinsed with deionized water, and then observed after drying. Whether the coating showed bubbling, peeling, discoloration, powdering and other phenomena was recorded, and the results are shown in Table 1.

[0069] Weather resistance: The energy storage and luminescent nano coating material prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 of the present application was brushed on a tinplate with a wet film thickness of 100 ± 10 μm, and dried for 7 days to obtain a test plate coating. A xenon lamp aging box was used, with an irradiance (at 340 nm) of 0.71 W / (m²·nm), a blackboard temperature of 65 ± 3°C, a relative humidity of 50 ± 5%, and a spraying cycle of 120 min (18 min of spraying and 102 min of drying). The test plate was fixed on the sample holder of the aging box and continuously exposed for 500 hours. The coating powdering grade (0-5), cracking degree, discoloration, peeling and bubbling were visually evaluated according to the standard, and the results are shown in Table 1.

[0070] Water resistance: The energy storage and luminescent nano coating material prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 of the present application was brushed on a tinplate with a wet film thickness of 100 ± 10 μm, and dried for 7 days to obtain a test plate coating. The test plate coating was immersed in deionized water, and after standing at 23 ± 2°C for 120 h, whether peeling, bubbling and discoloration occurred was recorded, and the results are shown in Table 1.

[0071] Luminescent performance test: The energy storage and luminescent nano coating material prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 of the present application was brushed on a white PVC plate (100 mm x 100 mm) with a wet film thickness of 150 ± 10 μm, and dried at room temperature for 7 days. A simulated sunlight box was used, with an irradiance of 1000 ± 50 W / m². The test plate was placed horizontally (with the coating facing up) at a distance of 30 cm from the light source, and absorbed sunlight for 2 hours. The test plate was quickly moved into a dark box (light shielding rate ≥ 99%, temperature 25 ± 2°C) to avoid external light interference. In the dark box, the afterglow brightness was measured at a distance of 30 cm (vertically aligned with the center) from the test plate surface at 10 min, 1 h and 2 h after being placed in the dark environment, and the results are shown in Table 1.

[0072] Table 1 Performance test results of Example 1-Example 3 and Comparative Example 1-Comparative Example 3 of the present application

[0073]

[0074] As shown in Table 1, the viscosity of the energy storage and luminescent nano-coating materials prepared in Examples 1-3 was 83-88 KU, and the surface drying time was ≤2h. They showed good performance in terms of alkali resistance (no abnormality after 96h), weather resistance (no abnormality after 500h), and water resistance (no abnormality after 120h). The afterglow brightness reached 473-485 mcd / m² at 10min, 64-77 mcd / m² at 1h, and 24-29 mcd / m² at 2h. In contrast, Comparative Example 1 had a viscosity of 75 KU, a surface drying time extended to 3h, slight blistering in alkali resistance, and grade 2 powdering in weather resistance. Comparative Example 1 showed localized whitening due to water resistance and a significant decrease in afterglow brightness (320 mcd / m² at 10 min, 42 mcd / m² at 1 h, and 15 mcd / m² at 2 h). Comparative Example 2, without the addition of modified nano-SiO2, had a viscosity of 79 KU, exhibited water resistance with edge peeling and weathering powdering at level 1, and a slight decrease in afterglow brightness (460 mcd / m² at 10 min). Comparative Example 3, without the addition of modified GQDs, showed a significant decrease in luminescent performance (350 mcd / m² at 10 min, 45 mcd / m² at 1 h, and 18 mcd / m² at 2 h).

[0075] Comparative Example 1, a one-time mixing and ball milling calcination method, without a core-shell stepwise preparation, resulted in decreased viscosity, prolonged surface drying time, deteriorated resistance to media (alkali resistance, water resistance, weather resistance), and a significant decrease in luminescence brightness. Example 1 achieved a structure of a luminescent core, transition layer, and outer shell through stepwise calcination. The transition layer (SrAl3O6) reduced interfacial dislocations and cracks through lattice matching. In contrast, Comparative Example 1, with its one-time mixing and calcination, saw direct contact between the SrAl2O4 and SrAl4O7 matrices, leading to increased lattice mismatch and more interfacial defects. These defects became "traps" for electron-hole recombination, increasing the probability of non-radiative transitions and decreasing luminescence efficiency. The brightness at 10 minutes was significantly lower than in Example 1. Furthermore, one-time mixing could not achieve Eu... 2+ Gradient doping (high concentration on the surface, low concentration inside) leads to Eu 2 + Local aggregation triggers fluorescence quenching; on the other hand, Dy 3+ and Li + Uneven distribution and inconsistent trap depths reduce electron storage capacity and shorten afterglow time; the high surface roughness of the coreless luminescent powder particles results in weak interfacial bonding with the silicone-acrylic emulsion and increased porosity within the coating, leading to decreased water resistance (local whitening after 120 hours) and weather resistance (powdering grade 2 after 500 hours); at the same time, uneven particle dispersion reduces viscosity to 75 KU and extends surface drying time to 3 hours.

[0076] Comparative Example 2 does not add modified nano-SiO2, the viscosity is slightly reduced, the water resistance and weather resistance are reduced, and the luminous brightness is slightly reduced. In the example, the modified nano-SiO2 is grafted with an acrylate group through KH-570, forms a covalent bond with the organic segment of the silicone-acrylate emulsion, fills the micro-defects of the coating, and improves the density. After the absence of the component in Comparative Example 2, the porosity of the coating increases, and water molecules and oxygen are more easily permeable, resulting in a decrease in water resistance (120h edge peeling) and a weakening of weather resistance (500h powdering grade 1). Moreover, nano-SiO2 can enhance the interfacial bonding between the luminescent powder and the base material, and the absence of it slightly reduces the compatibility of the luminescent powder with the silicone-acrylate emulsion, resulting in the appearance of micro-cracks in some areas, which leads to a decrease in afterglow brightness at 10min. On the other hand, the high specific surface area of nano-SiO2 can form a weak network structure through hydrogen bonding, which helps to thicken the system. Without the addition of nano-SiO2, the system only relies on the thixotropy of modified bentonite, and the viscosity is slightly reduced to 79KU.

[0077] Comparative Example 3 does not add modified GQDs, and the luminous brightness is significantly reduced, while other properties (viscosity, surface drying, and medium resistance) remain basically unchanged. In the example, modified GQDs can expand the excitation range by wide-spectrum absorption, efficiently absorb sunlight, and improve photon utilization. After the absence of GQDs in Comparative Example 3, only the inherent absorption of SrAl2O4:Eu 2+ is relied on, the excitation spectrum range is narrowed, the energy storage efficiency is reduced, and the brightness at 10min is reduced. Modified GQDs form an energy transfer channel with the luminescent powder through the SiO2 coating layer, which can convert long-wavelength light into effective excitation light for Eu 2+ . Without the addition of modified GQDs, the channel is interrupted, and long-wavelength light cannot be utilized, further reducing the luminous intensity.

[0078] The above results show and describe the basic principles and main features of the present application, as well as the advantages of the present application.

[0079] Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the equivalents of the appended claims.

Claims

1. An energy-storing and luminescent nano-coating material, characterized in that, It includes modified nano-SiO2, silicone-acrylic emulsion, polycarboxylate dispersant, composite luminescent powder and modified bentonite in a mass ratio of (1.8-2):100:1.8:(28-32):(0.5-0.7); The composite luminescent powder is obtained by reacting luminescent powder precursor, modified GQDs, tetraethyl orthosilicate and methyltrimethoxysilane; The luminescent powder precursor is obtained by calcining a luminescent intermediate material with SrCO3, Al2O3, Eu2O3, Dy2O3, and Li2CO3 in a mixed atmosphere at a mass ratio of 100:(14-16):(40-42):(1.5-2):(1-1.3):(0.06-0.08); the luminescent intermediate material is obtained by calcining a luminescent core material with SrCO3 and Al2O3 in a mixed atmosphere at a mass ratio of (19-21):3:6; the luminescent core material is obtained by calcining SrCO3, Al2O3, and Eu2O3 in a mixed atmosphere at a molar ratio of 1:(1-1.02):0.

002. The mixed atmosphere includes reducing gas and inert gas; The modified GQDs were obtained by modifying GQDs with 3-mercaptopropyltrimethoxysilane; The modified nano-SiO2 is obtained by modifying nano-SiO2 with a first silane coupling agent; The modified bentonite is obtained by modifying bentonite with a second silane coupling agent.

2. The energy storage and luminescent nanocoating material according to claim 1, characterized in that, The luminescent precursor is dispersed in anhydrous ethanol to obtain a luminescent precursor dispersion, and the modified GQDs are dispersed in anhydrous ethanol to obtain a modified GQDs dispersion. The volume ratio of the modified GQDs dispersion, the luminescent precursor dispersion, tetraethyl orthosilicate, and methyltrimethoxysilane is (1-1.2):50:4:0.

25. The reducing gas in the mixed atmosphere has a volume percentage of 5%, and the reducing gas is hydrogen. The inert gas is either nitrogen or argon. Both the first silane coupling agent and the second silane coupling agent are KH-570.

3. The energy storage and luminescent nanocoating material according to claim 1, characterized in that, The polycarboxylate dispersant is a sodium polycarboxylate dispersant with a solid content of 43%–45%; the bentonite contains ≥95% montmorillonite and has a particle size D50 ≤30μm; the GQDs have a size of 5–10nm; the silicone-acrylic emulsion is an acrylate-silicone emulsion with a solid content of 38%–40%, a viscosity of 90–110 mPa·s, a particle size of 80–100nm, and a pH of 7–8; the nano-SiO2 has a particle size of 10–30nm; and the SrCO3 and Al2O3 have a particle size <1μm.

4. A method for preparing an energy-storing and luminescent nano-coating material as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. SrCO3, Al2O3, and Eu2O3 are mixed, subjected to a first ball milling process, and then calcined in a mixed atmosphere to obtain a luminescent core material; the luminescent core material, SrCO3, and Al2O3 are mixed, subjected to a second ball milling process, and then calcined in a mixed atmosphere to obtain a luminescent intermediate material; the luminescent intermediate material is mixed with SrCO3, Al2O3, Eu2O3, Dy2O3, and Li2CO3, subjected to a third ball milling process, and then calcined in a mixed atmosphere to obtain a luminescent powder precursor. S2. Add 3-mercaptopropyltrimethoxysilane to the GQDs dispersion and carry out a first heating reaction to obtain modified GQDs; disperse the modified GQDs in anhydrous ethanol to obtain a modified GQDs dispersion; disperse the luminescent powder precursor in anhydrous ethanol to obtain a luminescent powder precursor dispersion; mix the modified GQDs dispersion and the luminescent powder precursor dispersion, add tetraethyl orthosilicate and methyltrimethoxysilane, adjust to the set pH, and react at room temperature to obtain a composite luminescent powder; S3. Disperse nano-SiO2 in anhydrous ethanol to obtain a nano-SiO2 dispersion. Add a first silane coupling agent to the nano-SiO2 dispersion and carry out a second heating reaction to obtain modified nano-SiO2. Prepare a silane hydrolysate with a second silane coupling agent. Mix bentonite with anhydrous ethanol to prepare a bentonite slurry. Heat the mixture to a set temperature and add the silane hydrolysate dropwise to the bentonite slurry. Maintain the temperature and carry out the reaction to obtain modified bentonite. S4. After dispersing the modified nano-SiO2 in the silicone-acrylic emulsion at a set stirring speed, while maintaining the stirring speed, add the polycarboxylate dispersant, composite luminescent powder and modified bentonite sequentially at set intervals to obtain the energy storage and luminescent nano-coating material.

5. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The first ball milling process is carried out at a speed of 300-400 rpm for 2-3 hours; the second ball milling process is carried out at a speed of 300-400 rpm for 1-1.5 hours; the third ball milling process is carried out at a speed of 350-450 rpm for 2-2.5 hours; anhydrous ethanol of the same mass as the solid material is added before the first, second, and third ball milling processes.

6. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The first calcination temperature is 1200-1250℃ and the time is 3-3.5h; the second calcination temperature is 1100-1150℃ and the time is 2-3h; the third calcination temperature is 1150-1200℃ and the time is 2-3h.

7. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The concentration of the GQDs dispersion is 1wt%-1.2wt%; the amount of 3-mercaptopropyltrimethoxysilane is 0.08%-0.12% of the GQDs dispersion; the concentration of the modified GQDs dispersion is 0.5wt%-0.8wt%; the concentration of the luminescent powder precursor dispersion is 10wt%-12wt%; the temperature of the first heating reaction is 60-65℃, and the time is 2-3h; the pH is set to 9; and the reaction time at room temperature is 2-3h.

8. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The concentration of the nano-SiO2 dispersion is 8wt%-10wt%, and the amount of the first silane coupling agent is 10%-12% of the mass of the nano-SiO2; the temperature of the second heating reaction is 65-75℃, and the time is 1-2h; the set temperature is 60-65℃, and the dropping rate is 1-3mL / min; the heat preservation reaction time is 2-3h; the volume ratio of the bentonite slurry to the silane hydrolysate is (3.8-4):

1.

9. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The specific steps for preparing the silane hydrolysate are as follows: the second silane coupling agent, anhydrous ethanol and deionized water are mixed at a ratio of (6-8):100:10, the pH is adjusted to 4-5 with hydrochloric acid, and the mixture is stirred for 20-30 minutes to obtain the solution.

10. The method for preparing an energy storage and luminescent nano-coating material according to claim 4, characterized in that, The set stirring speed is 1500-1600 rpm, and the set time is 15-30 min.

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