Blue-green fluorescent powder, fluorescent paint and preparation method and application thereof

Abstract

The invention discloses blue-green fluorescent powder, a fluorescent coating and a preparation method and application thereof. The preparation method of the blue-green fluorescent powder comprises the following steps: 1) providing raw material powder according to the chemical composition of the blue-green fluorescent powder, and mixing the raw material powder with a fluxing agent to obtain mixed powder; wherein the chemical composition of the blue-green fluorescent powder is SrAl2O4: Eu < 2 + >, Dy < 3 + >; the raw material of aluminum is alpha-type nano aluminum oxide; the weight of the fluxing agent is 1-5wt% of the weight of the raw material powder; 2) carrying out primary sintering on the mixed powder in a reducing atmosphere at 1000-1500 DEG C to obtain primary sintered powder; crushing and grinding the primary sintered powder, and then carrying out secondary sintering in a reducing atmosphere at 800-1400 DEG C to obtain secondary sintered powder; and (3) carrying out ball milling on the secondarily sintered powder for 0.5-10 hours to obtain the blue-green fluorescent powder. The blue-green fluorescent powder disclosed by the invention has relatively high initial afterglow intensity.

Description

Technical Field

[0001] This invention relates to a blue-green phosphor, a fluorescent coating, its preparation method, and its uses. Background Technology

[0002] Photoluminescent coatings are special coatings that absorb and store light energy (such as sunlight and lamplight), allowing them to emit light continuously in dark environments. The core principle is that fluorescent substances are activated under light, causing electrons to transition to a high-energy state, then slowly release energy and return to a low-energy state, releasing energy in the form of light and creating a afterglow effect. This characteristic of photoluminescent coatings makes them energy-saving and environmentally friendly, and therefore they are widely used in architectural decoration, illuminated signs on roads and bridges, fire safety signs, and emergency lighting. Since photoluminescent coatings are primarily used at night or in dark places, higher requirements are placed on the afterglow intensity and duration.

[0003] CN116554745A discloses a hydrophobic, photoluminescent coating. The raw materials for preparing this hydrophobic, photoluminescent coating, by mass percentage, include the following components: 45-55% polyacrylic acid emulsion, 15-20% long-afterglow luminescent material, 10-15% inorganic filler, 0.15-0.30‰ phosphor, 5-10% nano-silica, 2-5% additives, 2-4% hydrophobic agent, and the balance being deionized water. This hydrophobic, photoluminescent coating can reduce the amount of long-afterglow luminescent material while maintaining luminous brightness, thereby reducing costs, and the resulting coating exhibits good hydrophobicity and self-cleaning properties. However, the afterglow intensity of this hydrophobic, photoluminescent coating is not ideal.

[0004] CN120310349A discloses a fluorescent architectural coating. This fluorescent architectural coating comprises the following components by weight: 25-30 parts of a first luminescent material, 5-8 parts of a second luminescent material, 8-10 parts of an optical enhancing material, 150-200 parts of a water-based acrylic resin, 30-40 parts of deionized water, 2-3 parts of cerium oxide particles, 0.5-1 part of a UV absorber, 1-2 parts of a plasticizer, 1-2 parts of an antifreeze agent, 0.5-1 part of a defoamer, and 0.5-1 part of a polycarboxylate dispersant. The first luminescent material is SrAl2O4:Eu 2+ / Dy 3+ The second luminescent material is a self-made sodium fluorescein salt@SiO2. This fluorescent architectural coating combines high-efficiency fluorescence performance with long-term durability. However, the afterglow intensity of this fluorescent architectural coating is not ideal.

[0005] CN120988696A discloses a long-afterglow self-luminescent material based on multi-element rare earth synergistic sensitization. This long-afterglow self-luminescent material uses SrAl2O4 as a matrix and is doped with Eu. 2+ Dy 3+ 、Nd 3+Ternary rare earth ions form luminescent nuclei to be coated, Eu 2+ Dy 3+ and Nd 3+ A ZnO nanopillar array was epitaxially grown in situ on the surface of the luminescent core with a molar ratio of 1:(0.4–0.6):(0.2–0.4). A hydrophobically modified SiO2 shell, 50–100 nm thick, was then coated onto the ZnO nanopillars. This long-afterglow self-luminescent material, synthesized using a solid-phase process and industrial solid waste materials such as red mud / fly ash, achieves a relatively low carbon emission intensity. However, the afterglow intensity of this long-afterglow self-luminescent material is not high. Summary of the Invention

[0006] In view of the above, one object of the present invention is to provide a method for preparing a blue-green phosphor, wherein the blue-green phosphor prepared by the method has a high afterglow intensity. Another object of the present invention is to provide a blue-green phosphor. A further object of the present invention is to provide uses for the aforementioned blue-green phosphor. Yet another object of the present invention is to provide a fluorescent coating. Another object of the present invention is to provide a method for preparing the aforementioned fluorescent coating. Still another object of the present invention is to provide uses for the aforementioned fluorescent coating.

[0007] The present invention achieves the above objectives using the following technical solutions.

[0008] On one hand, the present invention provides a method for preparing blue-green phosphor, comprising the following steps: 1) Provide raw material powder according to the chemical composition of blue-green phosphor, and mix the raw material powder with flux to obtain a mixed powder; wherein, the chemical composition of the blue-green phosphor is SrAl2O4:Eu 2+ Dy 3+ The aluminum raw material is α-type nano-alumina; the flux is 1-5 wt% of the raw material powder weight. 2) The mixed powder is sintered once in a reducing atmosphere at 1000-1500℃ to obtain a first-sintered powder; the first-sintered powder is crushed and ground, and then sintered again in a reducing atmosphere at 800-1400℃ to obtain a second-sintered powder. 3) Ball mill the secondary sintered powder for 0.5 to 10 hours to obtain blue-green phosphor.

[0009] According to the preparation method of the present invention, preferably, in step 1), the raw materials further include oxides or inorganic salts of strontium, oxides or inorganic salts of europium, and oxides or inorganic salts of dysprosium.

[0010] According to the preparation method of the present invention, preferably, in step 1), the flux is composed of a boron-containing flux and a fluorine-containing flux, wherein the weight ratio of the boron-containing flux to the fluorine-containing flux is 1:0.1 to 10; the boron-containing flux is selected from at least one of boric acid, borate, and boron oxide; and the fluorine-containing flux is selected from at least one of alkali metal fluorides and alkaline earth metal fluorides.

[0011] According to the preparation method of the present invention, preferably, in step 2), the reducing atmosphere is composed of hydrogen gas with a volume percentage of 1 to 10 vol% and a protective gas with a volume percentage of 90 to 99 vol%. The first sintering time is 1 to 10 hours; the second sintering time is 1 to 10 hours.

[0012] On the other hand, the present invention also provides a blue-green phosphor prepared by any of the above preparation methods, wherein the initial afterglow intensity of the blue-green phosphor is 2 cd / m. 2 above.

[0013] Furthermore, the present invention also provides the use of the above-mentioned blue-green phosphor in the preparation of fluorescent coatings.

[0014] In another aspect, the present invention also provides a fluorescent coating, made from raw materials comprising the following parts by weight: 5 to 10 parts by weight of the above-mentioned blue-green phosphor, 1 to 5 parts by weight of yellow phosphor, 8 to 40 parts by weight of epoxy resin and 1 to 5 parts by weight of curing agent.

[0015] According to the fluorescent coating of the present invention, preferably, the chemical composition of the yellow phosphor is YAG:Ce. 3+ .

[0016] In another aspect, the present invention also provides a method for preparing the above-mentioned fluorescent coating, comprising the following steps: 1) Mix the above-mentioned blue-green phosphor with yellow phosphor to obtain a mixed phosphor; 2) Mix the mixed phosphor with epoxy resin to obtain fluorescent paint; 3) Fluorescent paint and curing agent are mixed to obtain fluorescent coating.

[0017] Furthermore, the present invention also provides the use of the above-mentioned fluorescent coating in building exterior wall decoration and signage, road or bridge signage, and emergency signage, wherein the initial afterglow intensity of the fluorescent coating is 1 cd / m². 2 The hardness is above 18.5HV.

[0018] The blue-green phosphor of the present invention has a high initial afterglow intensity, and the fluorescent coating prepared therefrom has good nighttime visibility. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0021] The "afterglow intensity" or "afterglow brightness" mentioned in this invention refers to the luminescence of a luminescent material at a certain moment after the excitation source is removed, and the unit is candela per square meter (cd / m²). 2 ).

[0022] The "hardness value" mentioned in this invention is the "Vickers hardness value," which refers to the hardness value obtained by pressing a square pyramidal diamond indenter into the material surface with a certain load and an angle of 136° between the two surfaces, holding it for a specified time, measuring the diagonal length of the indentation, and dividing the load value by the surface area of ​​the indentation pit. The unit is Vickers hardness value (HV).

[0023] ​​​​ <Preparation method of blue-green phosphor> The method for preparing the blue-green phosphor of the present invention includes a mixing step, a sintering step, and a ball milling step. These are described in detail below.

[0024] Mixing steps The raw material powder is provided according to the chemical composition of the blue-green phosphor, and the raw material powder is mixed with the flux to obtain the mixed powder.

[0025] According to one embodiment of the present invention, the chemical composition of the blue-green phosphor is SrAl2O4:Eu 2+ Dy 3+ .

[0026] According to one embodiment of the present invention, the aluminum (Al) raw material is α-type nano-alumina. According to a preferred embodiment of the invention, the particle size of the α-type nano-alumina can be at most 80 nm, preferably at most 60 nm, and more preferably at most 20 nm. Such α-type nano-alumina has high reactivity and specific surface area, which can promote uniform reaction of the raw material and reduce the formation of impurity phases. Its stable crystal structure can optimize grain distribution and reduce defect density, thereby significantly improving the initial afterglow intensity of the phosphor.

[0027] According to one embodiment of the present invention, the raw materials may further include oxides or inorganic salts of strontium (Sr), oxides or inorganic salts of europium (Eu), and oxides or inorganic salts of dysprosium (Dy). According to a preferred embodiment of the present invention, the inorganic salt may be a carbonate. According to a more preferred embodiment of the present invention, the raw materials include SrCO3, α-type nano-Al2O3, Eu2O3, and Dy2O3.

[0028] According to one embodiment of the present invention, the weight of the flux can be 1 to 5 wt% of the weight of the raw material powder, preferably 1.5 to 4.5 wt%, and more preferably 2 to 4 wt%.

[0029] According to one embodiment of the present invention, the flux can be a combination of a boron-containing flux and a fluorine-containing flux. The weight ratio of the boron-containing flux to the fluorine-containing flux can be 1:0.1 to 10, preferably 1:0.2 to 8, and more preferably 1:0.5 to 5.

[0030] According to a preferred embodiment of the present invention, the boron-containing flux can be selected from at least one of boric acid, borate, and boron oxide, preferably at least one of boric acid and boron oxide, and more preferably boric acid (H3BO3). The fluorine-containing flux can be selected from at least one of alkali metal fluorides and alkaline earth metal fluorides, preferably at least one of LiF, NaF, KF, CaF2, MgF2, and BaF2, and more preferably at least one of LiF, NaF, and KF.

[0031] Appropriate fluxes can promote the melting and reaction of raw materials, help form a uniform crystal structure, reduce sintering temperature, and improve the initial afterglow intensity of phosphors.

[0032] The raw materials used in this invention can be commercially available products or prepared by existing methods, and are not particularly limited herein. The purity of the raw materials in this invention is at least industrial grade (99.9 wt%).

[0033] Sintering steps The mixed powder is sintered once in a reducing atmosphere at 1000–1500℃ to obtain a first-sintered powder. The first-sintered powder is crushed and ground, and then sintered a second time in a reducing atmosphere at 800–1400℃ to obtain a second-sintered powder.

[0034] In this invention, the reducing atmosphere refers to the atmosphere formed by introducing a mixture of hydrogen and a protective gas. According to one embodiment of the invention, the volume percentage of hydrogen can be 1–10 vol%, preferably 2–9 vol%, more preferably 3–8 vol%. The volume percentage of the protective gas can be 90–99 vol%, preferably 91–98 vol%, more preferably 92–97 vol%.

[0035] In this invention, the protective gas can be selected from at least one of nitrogen and inert gas, preferably at least one of nitrogen, helium, neon and argon, and more preferably at least one of nitrogen, helium and argon.

[0036] According to one embodiment of the present invention, the temperature for the first sintering can be 1000–1500°C, preferably 1100–1400°C, and more preferably 1200–1350°C. The sintering time for the first sintering can be 1–10 h, preferably 2–8 h, and more preferably 3–6 h.

[0037] In this invention, both crushing and grinding can be performed using equipment or methods known in the art, and no particular limitation is made here. For example, grinding can be performed using an agate grinding media. According to a preferred embodiment of the invention, the grinding time can be 5 to 60 minutes, preferably 10 to 50 minutes, and more preferably 15 to 45 minutes.

[0038] According to one embodiment of the present invention, the temperature of the secondary sintering can be 800–1400°C, preferably 950–1300°C, and more preferably 1000–1250°C. The time of the secondary sintering can be 1–10 h, preferably 2–7 h, and more preferably 3–5 h.

[0039] In this invention, sintering can be performed in any high-temperature resistant equipment known in the art, without any particular limitation. For example, it can be performed in a high-temperature sintering furnace.

[0040] A proper reducing atmosphere can ensure Eu 3+ Successfully restored to Eu 2+ This improves the afterglow performance of the phosphor. Appropriate heating conditions, combined with the composition of the phosphor raw materials, especially the effect of α-type nano-alumina, are more conducive to promoting the formation of the phosphor matrix lattice and enhancing the afterglow performance of the rare earth activator (Eu). 2+ Dy 3+ It enters the matrix lattice, forming a good crystal structure, making its structure more complete, thereby improving the initial afterglow intensity of the phosphor, ensuring that the phosphor can absorb ultraviolet rays in sunlight, store the energy therein, and emit blue-green light.

[0041] This invention employs a secondary sintering process, which can optimize the crystal structure, adjust the oxygen vacancy concentration, and optimize the trap energy level; it can also control the grain size to avoid abnormal grain growth or agglomeration, thereby helping to reduce light scattering and energy loss and significantly improve the initial afterglow intensity of the phosphor.

[0042] Ball milling steps The sintered powder was ball-milled to obtain blue-green phosphor.

[0043] According to one embodiment of the present invention, the ball milling time can be 0.5 to 10 hours, preferably 0.8 to 8 hours, and more preferably 1 to 6 hours.

[0044] Limiting the ball milling time to the above range is beneficial for refining phosphor particles and optimizing phosphor crystal structure, reducing surface defects, thereby reducing light scattering and non-radiative recombination, and significantly improving the initial afterglow intensity of phosphor after sintering.

[0045] In this invention, ball milling can be implemented using any ball milling equipment known in the art, without particular limitation. For example, a planetary ball mill can be used. According to one embodiment of the invention, the material of the grinding media used in the ball mill can be at least one of stainless steel, agate, zirconium dioxide, ceramics, and silicon carbide, preferably at least one of agate, zirconium dioxide, and ceramics, and more preferably at least one of agate and zirconium dioxide. The weight ratio of the grinding media to the secondary sintered powder can be 1:1 to 5, preferably 1:1 to 3, and more preferably 1:2 to 3.

[0046] According to one embodiment of the present invention, a combination of grinding balls of three different diameters (large, medium, and small) can be used as the grinding media, which is beneficial for the secondary sintered powder to be ground more thoroughly and uniformly. According to a preferred embodiment of the present invention, the diameter of the large-diameter grinding ball can be 14–20 mm, preferably 14–18 mm, and more preferably 15–18 mm. The diameter of the medium-diameter grinding ball can be 9–13 mm, preferably 9–12 mm, and more preferably 10–12 mm. The diameter of the small-diameter grinding ball can be 2–8 mm, preferably 3–8 mm, and more preferably 3–7 mm. The mass ratio of the large, medium, and small-diameter grinding balls can be 1:1–5:1–8, preferably 1:2–5:2–8, and more preferably 1:2–4:3–7.

[0047] <Blue-green fluorescent powder> The blue-green phosphor of this invention can absorb ultraviolet rays from sunlight, store the energy therein, and emit a blue-green color at night. The blue-green phosphor of this invention has a high initial afterglow intensity.

[0048] The chemical composition of the blue-green phosphor is SrAl2O4:Eu 2+ Dy 3+ .

[0049] According to one embodiment of the present invention, the initial afterglow intensity of the blue-green phosphor can be 2 cd / m². 2 The preferred value is 2.4 cd / m³. 2 The above, more preferably 2.45 cd / m 2 above.

[0050] <Uses of blue-green phosphors> The present invention also provides the use of the above-mentioned blue-green phosphor in the preparation of fluorescent coatings.

[0051] The simultaneous application of blue-green phosphor and yellow phosphor in fluorescent coatings of the present invention can enable the fluorescent coatings to obtain cool white light at night, improve nighttime visibility, and give the fluorescent coatings a higher initial afterglow intensity.

[0052] Fluorescent Coatings The present invention also provides a fluorescent coating, which is made from raw materials comprising the following parts by weight: 5 to 10 parts by weight of the above-mentioned blue-green phosphor, 1 to 5 parts by weight of yellow phosphor, 8 to 40 parts by weight of epoxy resin and 1 to 5 parts by weight of curing agent.

[0053] According to one embodiment of the present invention, the amount of blue-green phosphor can be 5 to 10 parts by weight, preferably 5.5 to 9 parts by weight, and more preferably 6 to 8 parts by weight.

[0054] In this invention, the yellow phosphor can be a commercially available yellow phosphor, preferably a commercially available rare-earth garnet yellow phosphor, and more preferably a phosphor with a chemical composition of YAG:Ce. 3+ Commercial yellow fluorescent powder. According to one embodiment of the present invention, the amount of yellow fluorescent powder used can be 1 to 5 parts by weight, preferably 1.5 to 4.5 parts by weight, and more preferably 2 to 4 parts by weight.

[0055] In this invention, the epoxy resin can be any type of epoxy resin known in the art that can be used in architectural coatings, and no particular limitation is made here. For example, it can be a glycidyl ether type epoxy resin, preferably at least one of bisphenol A type epoxy resin, phenolic epoxy resin, and aliphatic glycidyl ether type epoxy resin. According to one embodiment of the present invention, the amount of epoxy resin can be 8 to 40 parts by weight, preferably 9 to 30 parts by weight, and more preferably 10 to 25 parts by weight.

[0056] In this invention, the curing agent can be any type of curing agent known in the art for use in architectural coatings, and no particular limitation is made here. For example, it can be a commercially available architectural coating curing agent, which is generally mainly composed of polyetheramine, alicyclic amine, diluent, etc. According to one embodiment of the invention, the amount of curing agent can be 1 to 5 parts by weight, preferably 2 to 4.5 parts by weight, and more preferably 2.5 to 4 parts by weight.

[0057] In the fluorescent coating of this invention, blue-green phosphor absorbs ultraviolet rays from sunlight, storing the energy and emitting blue-green light at night. Excited by the blue-green light, yellow phosphor emits yellow fluorescence. Combined with the blue-green light, this results in the coating emitting a cool white light, thereby improving nighttime visibility. Epoxy resin has good light transmittance and can act as a binder, giving the fluorescent coating good mechanical properties and chemical stability. After curing, it adheres stably to the surface of the coated object and is not easily peeled off.

[0058] <Preparation Method of Fluorescent Coating> The present invention also provides a method for preparing the above-mentioned fluorescent coating, comprising a step of mixing phosphor, a step of mixing epoxy resin, and a step of mixing curing agent. This will be described in detail below.

[0059] Mixing phosphor steps Mixing blue-green phosphor with yellow phosphor yields a mixed phosphor.

[0060] In this invention, mixing can be performed using any mixing equipment known in the art, without particular limitation. For example, a drum mill can be used. According to one embodiment of the invention, the mixing time can be 18–30 hours, preferably 20–28 hours, and more preferably 22–26 hours. Such mixing conditions ensure that the blue-green phosphor and yellow phosphor are mixed more thoroughly and uniformly, which is beneficial to improving the luminescence uniformity of the fluorescent coating.

[0061] Steps for mixing epoxy resin Fluorescent paint is obtained by mixing fluorescent powder with epoxy resin.

[0062] In this invention, the mixing of epoxy resins can be achieved in any mixing or stirring equipment known in the art, and no particular limitation is made here.

[0063] According to one embodiment of the present invention, the mixing time can be 10 to 60 minutes, preferably 15 to 50 minutes, and more preferably 20 to 45 minutes.

[0064] Such mixing conditions ensure that the phosphor and epoxy resin are mixed more thoroughly and evenly, which is beneficial to further improve the luminescence uniformity of the fluorescent coating.

[0065] Mixing curing agent steps Fluorescent paint is prepared by mixing fluorescent paint with a curing agent.

[0066] In this invention, the mixing of curing agents can be achieved in any mixing or stirring equipment known in the art, and no particular limitation is made here.

[0067] According to one embodiment of the present invention, the mixing time can be 1 to 10 minutes, preferably 2 to 8 minutes, and more preferably 3 to 7 minutes.

[0068] Such mixing conditions ensure that the fluorescent paint and the curing agent are mixed more thoroughly and evenly, which is beneficial to improving the adhesion uniformity of the fluorescent coating.

[0069] <Applications of Fluorescent Coatings> The present invention also provides the use of the above-mentioned fluorescent coating in building exterior wall decoration and signage, road or bridge signage and emergency signage.

[0070] According to one embodiment of the present invention, the initial afterglow intensity of the fluorescent coating can be 1 cd / m². 2 The preferred value is 1.05 cd / m³. 2 The above, more preferably 1.07 cd / m 2 above.

[0071] According to one embodiment of the present invention, the hardness of the fluorescent coating can be 18.5 HV or higher, preferably 18.8 HV or higher, and more preferably 19 HV or higher.

[0072] The fluorescent coating of the present invention has high initial afterglow intensity and high hardness, good nighttime visibility and is not easily peeled or damaged.

[0073] <Testing Method> Afterglow intensity testing: The CY-1000B long afterglow phosphor photometric performance testing system manufactured by Hangzhou Yuanfang Co., Ltd. was used for testing. The testing method is as follows: The sample to be tested was placed in a dark room for 24 hours to release the trapping energy in the sample, and then tested in the testing system. During the test, 1000lx light was used for 30 minutes, followed by afterglow performance testing.

[0074] Hardness testing: The NEMESIS-9100 microhardness tester manufactured by INNOVATEST was used for testing, with a test force of 200g.

[0075] Chromaticity coordinate detection: The OHSP-350M photoelectric color comprehensive testing system produced by Hangzhou Hongpu Optoelectronic Technology Co., Ltd. was used for testing.

[0076] <Ingredient Description> Unless otherwise specified, all raw materials used in the following examples are commercially available products.

[0077] Among them, YAG:Ce 3+ The yellow fluorescent powder was purchased from Shenzhen Mengzhi Technology Co., Ltd.

[0078] α-type nano-Al2O3 was purchased from Sinopharm Chemical Reagent Co., Ltd., with a primary particle size ≤20nm.

[0079] Micron-sized Al2O3 was purchased from Sinopharm Chemical Reagent Co., Ltd., with an average particle size D. 50 It is 79.4 μm.

[0080] Bisphenol A type epoxy resin was purchased from Shenzhen Juhengchuang Electronic Materials Co., Ltd.

[0081] The curing agent was purchased from Shenzhen Juhengchuang Electronic Materials Co., Ltd., and its main components are 30wt% of polyetheramine (O,O'-bis(2-aminopropyl)polypropylene glycol) with CAS number 9046-10-0, 28wt% of alicyclic amine (3,3'-dimethyl-4,4-diaminodicyclohexylmethane) with CAS number 6864-37-5, and 34.6wt% of diluent (isobutyl methyl ketone peroxide with CAS number 37206-20-5).

[0082] Thermal insulation material for building exterior walls, with specifications of 600mm×900mm×16mm.

[0083] Example 1 Preparation of blue-green phosphor: According to SrAl2O4:Eu 2+ Dy 3+ The chemical composition provides raw powder materials of SrCO3, α-type nano Al2O3, Eu2O3 and Dy2O3, and then 1.5 wt% H3BO3 and 1.5 wt% LiF of the raw powder are added and mixed to obtain a mixed powder.

[0084] The mixed powder was placed in a high-temperature sintering furnace, and a mixed gas of 5 vol% H2 and 95 vol% N2 was introduced. Sintering was carried out at 1300℃ for 4 hours. Then, it was allowed to cool naturally to room temperature (25℃), and the first-sintered powder was removed. The first-sintered powder was crushed and ground with an agate grinding media for 30 minutes. Next, the crushed and ground first-sintered powder was placed back into the high-temperature sintering furnace, and a mixed gas of 5 vol% H2 and 95 vol% N2 was introduced. Sintering was carried out again at 1200℃ for 4 hours, and then allowed to cool naturally to room temperature (25℃) to obtain the second-sintered powder.

[0085] The secondary sintered powder was placed in a planetary ball mill, and zirconium dioxide grinding balls with diameters of 16 mm, 10 mm and 6 mm were combined in a mass ratio of 1:3:6 as grinding media. The ball-to-material ratio was 1:2. The grinding was carried out for 1 hour to obtain blue-green fluorescent powder.

[0086] Comparative Example 1 The only difference from Example 1 is that the ball milling time is 18 hours.

[0087] Comparative Example 2 The only difference from Example 1 is that H3BO3 and LiF are not added.

[0088] Comparative Example 3 The only difference from Example 1 is that micron-sized Al2O3 is used instead of α-type nano Al2O3.

[0089] Application Example 1 Preparation of fluorescent coatings: 0.7 kg of the blue-green phosphor prepared in Example 1 was mixed with 0.3 kg of YAG:Ce 3+ Yellow phosphors were mixed in a drum mill for 24 hours to obtain mixed phosphors.

[0090] Mix 1 kg of mixed fluorescent powder with 1 kg of bisphenol A type epoxy resin and stir for 30 min to obtain fluorescent paint.

[0091] Mix 2 kg of fluorescent paint with 0.33 kg of curing agent and stir for 5 minutes to obtain fluorescent coating.

[0092] Application Comparison Example 1 The only difference from Application Example 1 is that 0.3 kg of the blue-green phosphor prepared in Example 1 is mixed with 0.7 kg of YAG:Ce 3+ Yellow phosphors are mixed to obtain mixed phosphors.

[0093] Experimental Example 1 The initial afterglow intensity of the blue-green phosphors prepared in Example 1 and Comparative Examples 1-3 was measured respectively, and the results are shown in Table 1 below.

[0094] Table 1 Grouping <![CDATA[Initial afterglow intensity (cd / m 2 )]]> Example 1 2.462 Comparative Example 1 0.396 Comparative Example 2 1.248 Comparative Example 3 1.691 As shown in Table 1, the blue-green phosphor of the present invention has a high initial afterglow intensity.

[0095] Application Experiment Example 1 The fluorescent coatings prepared in Application Example 1 and Application Comparative Example 1 were applied to building exterior wall insulation materials by scraping and cured for 24 hours.

[0096] The afterglow intensity and hardness of the cured fluorescent coating layer were tested, and the results are shown in Table 2 below.

[0097] Table 2 Grouping <![CDATA[Initial afterglow intensity (cd / m 2 ).]]> Hardness (HV) Application Example 1 1.072 19.1 Application Example 2 0.701 18.7 As shown in Table 2, the fluorescent coating of the present invention has high initial afterglow intensity and hardness.

[0098] The cured fluorescent coating layer was excited for 5 minutes using a 365nm ultraviolet lamp, and then the chromaticity coordinates of the fluorescent coating layer were measured. The results are shown in Table 3 below.

[0099] Table 3 Grouping x y Application Example 1 0.3887 0.5429 Application Comparison Example 1 0.3928 0.5788 As can be seen from the chromaticity coordinates in Table 3, the fluorescent coating of the present invention emits cool white light under ultraviolet light excitation, while Comparative Example 1 emits yellow-green light under ultraviolet light excitation.

[0100] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A method for preparing a blue-green phosphor, characterized in that, Includes the following steps: 1) Provide raw material powder according to the chemical composition of blue-green phosphor, and mix the raw material powder with flux to obtain a mixed powder; wherein, the chemical composition of the blue-green phosphor is SrAl2O4:Eu 2+ Dy 3+ The aluminum raw material is α-type nano-alumina; the flux is 1-5 wt% of the raw material powder weight. 2) The mixed powder is sintered once in a reducing atmosphere at 1000-1500℃ to obtain a first-sintered powder; the first-sintered powder is crushed and ground, and then sintered again in a reducing atmosphere at 800-1400℃ to obtain a second-sintered powder. 3) Ball mill the secondary sintered powder for 0.5 to 10 hours to obtain blue-green phosphor.

2. The preparation method according to claim 1, characterized in that, In step 1), the raw materials also include oxides or inorganic salts of strontium, oxides or inorganic salts of europium, and oxides or inorganic salts of dysprosium.

3. The preparation method according to claim 1, characterized in that, In step 1), the flux is composed of a boron-containing flux and a fluorine-containing flux, and the weight ratio of the boron-containing flux to the fluorine-containing flux is 1:0.1 to 10; the boron-containing flux is selected from at least one of boric acid, borate, and boron oxide; the fluorine-containing flux is selected from at least one of alkali metal fluorides and alkaline earth metal fluorides.

4. The preparation method according to claim 1, characterized in that, In step 2), the reducing atmosphere consists of hydrogen gas with a volume percentage of 1 to 10 vol% and a protective gas with a volume percentage of 90 to 99 vol%. The first sintering time is 1 to 10 hours; the second sintering time is 1 to 10 hours.

5. The blue-green phosphor prepared by the preparation method according to any one of claims 1 to 4, characterized in that, The initial afterglow intensity of the blue-green phosphor is 2 cd / m. 2 above.

6. The use of the blue-green phosphor according to claim 5 in the preparation of fluorescent coatings.

7. A fluorescent coating, characterized in that, The fluorescent coating is made from raw materials comprising the following parts by weight: 5 to 10 parts by weight of the blue-green phosphor as described in claim 5, 1 to 5 parts by weight of the yellow phosphor, 8 to 40 parts by weight of the epoxy resin, and 1 to 5 parts by weight of the curing agent.

8. The fluorescent coating according to claim 7, characterized in that, The chemical composition of the yellow phosphor is YAG:Ce 3 + .

9. A method for preparing a fluorescent coating according to claim 7 or 8, characterized in that, Includes the following steps: 1) Mix the blue-green phosphor according to claim 5 with a yellow phosphor to obtain a mixed phosphor; 2) Mix the mixed phosphor with epoxy resin to obtain fluorescent paint; 3) Fluorescent paint and curing agent are mixed to obtain fluorescent coating.

10. The use of fluorescent coatings according to claim 7 or 8 in building exterior wall decoration and signage, road or bridge signage, and emergency signage, characterized in that, The initial afterglow intensity of the fluorescent coating is 1 cd / m. 2 The hardness is above 18.5HV.