Water-based fluorescent paint and preparation method thereof

Abstract

The invention discloses a water-based fluorescent paint and a preparation method thereof, and belongs to the technical field of fluorescent paints.The water-based fluorescent paint is prepared from, by weight, 20-50 parts of modified fluorescent powder, 30-60 parts of modified acrylic emulsion, 0.5-3 parts of wetting dispersant, 0.1-1 part of defoaming agent, 2-8 parts of coalescing agent, 0.2-1.5 parts of flatting agent, 0.2-2 parts of thickening agent and 10-30 parts of deionized water. The dosage of the cross-linking agent in the modified fluorescent powder is 3-10% of the weight of the shell monomer, and the value is recorded as X; the dosage of a cross-linking monomer in the modified acrylic emulsion is 1.5-7.5% of the weight of the basic monomer, the value is recorded as Y, and meanwhile, Y / X is equal to 0.75-1.5; the fluorescent powder coated polymer shell layer and the acrylic emulsion are synergistically modified, so that the problem of phase separation caused by interfacial energy difference is fundamentally solved, and the water-based fluorescent paint with better comprehensive performance is obtained.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent coating technology, specifically relating to a water-based fluorescent coating and its preparation method. Background Technology

[0002] Water-based fluorescent coatings are widely used in traffic signs, safety warnings, architectural decoration, advertising, artistic creation, and special equipment due to their advantages such as environmental friendliness, safety, vibrant colors, and outstanding warning effects. Compared with traditional solvent-based fluorescent coatings, water-based coatings use water as the dispersion medium, have a low content of volatile organic compounds, and meet increasingly stringent environmental protection requirements. However, the fluorescence stability of water-based fluorescent coatings under long-term weathering has not yet reached the level comparable to solvent-based products.

[0003] Existing technologies often attribute the problem to the poor water resistance of phosphors and the insufficient performance of water-based resins, and accordingly modify the phosphors or improve the mechanical strength of water-based resins. However, the modification of phosphors and water-based resins often does not take into account compatibility, resulting in a huge difference in interfacial energy between the two. During film formation and service, micro-phase separation is very likely to occur, leading to phosphor aggregation or the formation of micro- or nano-scale voids or weak boundary layers between the phosphor and the resin matrix. Under environmental stress, these voids become the starting point for crack initiation and propagation, accelerating the penetration of quenching factors such as moisture and oxygen. At the same time, the micro-inhomogeneity caused by phase separation leads to the unnecessary scattering of incident and emitted light, resulting in low initial fluorescence efficiency and rapid decay of the coating.

[0004] Therefore, how to construct an integrated interface structure that transitions from phosphor to waterborne resin to eliminate phase separation and ensure efficient fluorescence transmission and long-term coating durability is the core technical problem that this invention needs to solve. Summary of the Invention

[0005] The purpose of this invention is to provide a water-based fluorescent coating and its preparation method. By synergistically designing the chemical structure of the fluorescent powder-coated polymer shell and the modified acrylic emulsion, especially by controlling the matching of the amounts of crosslinking agents and crosslinking monomers and the complementarity of functional groups, the interfacial energy matching and the interpenetration / interweaving of polymer segments in the interfacial region are achieved. This fundamentally solves the phase separation problem caused by the difference in interfacial energy, and obtains a water-based fluorescent coating with high fluorescence brightness, strong water resistance, excellent mechanical properties and long-term durability.

[0006] The objective of this invention can be achieved through the following technical solutions: A water-based fluorescent coating comprises the following raw materials in parts by weight: 20-50 parts modified fluorescent powder, 30-60 parts modified acrylic emulsion, 0.5-3 parts wetting and dispersing agent, 0.1-1 parts defoamer, 2-8 parts film-forming aid, 0.2-1.5 parts leveling agent, 0.2-2 parts thickener, and 10-30 parts deionized water; The modified phosphor is a phosphor with a polymer shell coating on its surface. The polymer shell is formed by in-situ polymerization of shell monomers, bonding monomers and crosslinking agents. The amount of shell monomers is 17-24% of the weight of the phosphor, and the amount of crosslinking agents is 3-10% of the weight of the shell monomers. This value is denoted as X. The modified acrylic emulsion is an acrylic copolymer emulsion containing a base monomer, a functional monomer, and a crosslinking monomer. The amount of the crosslinking monomer is 1.5-7.5% of the weight of the base monomer, denoted as Y, and the ratio of Y to X is 0.75-1.5.

[0007] Furthermore, the modified phosphor is prepared by the following method: A1. Add the fluorescent powder and sodium dodecylbenzene sulfonate to deionized water and ultrasonically disperse for 30 min to obtain a fluorescent powder suspension; A2. After mixing the shell monomer, bonding monomer and crosslinking agent evenly, add them to deionized water containing sodium dodecyl sulfate and emulsify at high speed for 15 minutes to obtain the shell pre-emulsion. A3. Under nitrogen protection and stirring at 70℃, the shell pre-emulsion and the first initiator solution were simultaneously and uniformly added to the phosphor suspension through two constant pressure dropping funnels over 3 hours. After the addition was completed, the temperature was raised to 80℃ and kept at that temperature for 2 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified phosphor.

[0008] Further, in step A1, the mass ratio of the phosphor, sodium dodecylbenzenesulfonate, and deionized water is 100:2:400; the phosphor is a long-afterglow phosphor, SrAl2O4:Eu,Dy. Further, in step A2, the ratio of the shell monomer, bonding monomer, crosslinking agent, sodium dodecyl sulfate, and deionized water is 17-24:0.34-0.48:0.51-2.4:1:30; the shell monomer is a mixture of styrene, methyl methacrylate, and butyl acrylate in a mass ratio of 8-12:5-8:4; the bonding monomer is methacrylic acid or hydroxyethyl acrylate; and the crosslinking agent is divinylbenzene or ethylene glycol dimethacrylate.

[0009] Further, in step A3, the mass ratio of the shell pre-emulsion, the first initiator solution, and the phosphor suspension is 48.85-57.88:20-40:502; the first initiator solution is a 1.5wt% potassium persulfate aqueous solution.

[0010] Furthermore, the modified acrylic emulsion is prepared by the following method: B1. Add the basic monomer, functional monomer, crosslinking monomer and reactive emulsifier to deionized water and emulsify at high speed to obtain a monomer pre-emulsion; B2. Add 5% of the total mass of monomer pre-emulsion and the second initiator solution to deionized water heated to 80°C to initiate polymerization. After the emulsion turns blue, start to add the remaining monomer pre-emulsion and the second initiator solution dropwise simultaneously, controlling the dropwise addition to be completed within 3 hours. After the dropwise addition is completed, raise the temperature to 85°C and keep it at that temperature for 1 hour. Cool it down, adjust the pH to 8.5 with ammonia water, filter it, and obtain the modified acrylic emulsion.

[0011] Further, in step B1, the mass ratio of the base monomer, functional monomer, crosslinking monomer, reactive emulsifier, and deionized water is 90:6:3.825-6.75:3-4:120; the base monomer is a mixture of styrene, methyl methacrylate, and butyl acrylate in a mass ratio of 25-30:30:30-35; the functional monomer is a mixture of acrylic acid and hydroxyethyl acrylate in a mass ratio of 2.5-3.5:2.5-3.5; the crosslinking monomer is divinylbenzene or ethylene glycol dimethacrylate; and the reactive emulsifier is sodium allyl hydroxypropyl sulfonate.

[0012] Further, in step B2, the mass ratio of the monomer pre-emulsion, the second initiator solution, and the deionized water is 222.825-226.75:180-200:50; the second initiator solution is a 2wt% ammonium persulfate aqueous solution.

[0013] Furthermore, the wetting and dispersing agent is an ammonium polyacrylate, specifically SN-5040; the defoamer is an organosilicon, specifically BYK-024; the film-forming aid is one of dodecyl alcohol ester and propylene glycol phenyl ether; the leveling agent is polyether siloxane; and the thickener is an alkali-swellable acrylic, specifically ASE-60.

[0014] A method for preparing a water-based fluorescent coating includes the following steps: Modified fluorescent powder, modified acrylic emulsion, wetting and dispersing agent, half of the defoamer and deionized water are added to a high-speed disperser and mixed at 800-1500 rpm for 20-40 min. Then the speed is reduced to 300-500 rpm, and film-forming aid, leveling agent and the remaining defoamer are added in sequence and stirred evenly. The pH of the system is then adjusted to 8.5-9.0 with ammonia water. Finally, a thickener is added to adjust the viscosity. After filtration, the mixture is sealed and cured for no less than 24 h to obtain water-based fluorescent coating.

[0015] Beneficial effects: This invention achieves phase separation and interfacial integration by precisely controlling the matching of the crosslinking agent content in the polymer shell and the crosslinking monomer content in the modified acrylic emulsion (ratio 0.7-1.5), as well as the complementarity of chemical functional groups. This enables two polymers that were originally incompatible to form a transitional structure in the interfacial region where crosslinking networks interpenetrate and functional groups interact, fundamentally eliminating phase separation and achieving interfacial integration. This solves the problem of microscopic phase separation caused by differences in interfacial energy. The synergistic system of this invention exhibits a superlinear performance leap in water resistance and weather resistance tests, proving that the matched cross-linking network and functional groups not only provide physical barriers but also completely block the longitudinal penetration channels of water vapor along the interface through strong interfacial bonding. In contrast, the improvement in water resistance and weather resistance is linear and limited when modifying phosphors or acrylic emulsions alone. Due to the elimination of light scattering caused by phase separation, the initial fluorescence brightness of the coating of this invention is significantly improved compared to the single-modification system. During UV accelerated aging, the integrated interface greatly inhibits coating chalking and phosphor detachment caused by interfacial degradation, resulting in an order-of-magnitude advantage in fluorescence intensity retention after aging. In addition, the interfacial integration allows for effective stress transfer within the coating. The pencil hardness and adhesion of the coating are significantly improved, which is not a simple sum of the properties of the modified phosphors and modified acrylic emulsions, but rather a higher level achieved through synergistic effects that cannot be reached by modification of a single component alone. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 This embodiment provides a modified phosphor powder, prepared by the following method: A1. Add 100g of SrAl2O4:Eu,Dy long afterglow phosphor (average particle size of 15μm) and 2g of sodium dodecylbenzenesulfonate to 400g of deionized water and ultrasonically disperse for 30min to obtain a phosphor suspension. A2. Mix 8g of styrene, 5g of methyl methacrylate, 4g of butyl acrylate, 0.34g of hydroxyethyl acrylate and 0.51g of divinylbenzene (X=3%) evenly, then add 1g of sodium dodecyl sulfate to 30g of deionized water and mix evenly. Then add the above mixture and emulsify at high speed for 15min to obtain the shell pre-emulsion. A3. Under nitrogen protection and stirring at 70℃, the shell pre-emulsion obtained in step A2 and 20g of 1.5wt% potassium persulfate aqueous solution were simultaneously and uniformly added to the phosphor suspension obtained in step A1 through two constant pressure dropping funnels over 3 hours. After the addition was completed, the temperature was raised to 80℃ and kept at that temperature for 2 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified phosphor.

[0018] Example 2 This embodiment provides a modified phosphor powder, prepared by the following method: A1. Add 100g of SrAl2O4:Eu,Dy long afterglow phosphor (average particle size of 15μm) and 2g of sodium dodecylbenzenesulfonate to 400g of deionized water and ultrasonically disperse for 30min to obtain a phosphor suspension. A2. Mix 10g of styrene, 7g of methyl methacrylate, 4g of butyl acrylate, 0.42g of hydroxyethyl acrylate and 1.26g of divinylbenzene (X=6%) evenly, then add 1g of sodium dodecyl sulfate to 30g of deionized water and mix evenly. Then add the above mixture and emulsify at high speed for 15min to obtain a shell pre-emulsion. A3. Under nitrogen protection and stirring at 70℃, the shell pre-emulsion obtained in step A2 and 30g of 1.5wt% potassium persulfate aqueous solution were simultaneously and uniformly added to the phosphor suspension obtained in step A1 through two constant pressure dropping funnels over 3 hours. After the addition was completed, the temperature was raised to 80℃ and kept at that temperature for 2 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified phosphor.

[0019] Example 3 This embodiment provides a modified phosphor powder, prepared by the following method: A1. Add 100g of SrAl2O4:Eu,Dy long afterglow phosphor (average particle size of 15μm) and 2g of sodium dodecylbenzenesulfonate to 400g of deionized water and ultrasonically disperse for 30min to obtain a phosphor suspension. A2. Mix 12g of styrene, 8g of methyl methacrylate, 4g of butyl acrylate, 0.48g of methacrylic acid and 2.4g of ethylene glycol dimethacrylate (X=10%) evenly, then add 1g of sodium dodecyl sulfate to 30g of deionized water and mix evenly. Then add the above mixture and emulsify at high speed for 15min to obtain a shell pre-emulsion. A3. Under nitrogen protection and stirring at 70℃, the shell pre-emulsion obtained in step A2 and 40g of 1.5wt% potassium persulfate aqueous solution were simultaneously and uniformly added to the phosphor suspension obtained in step A1 through two constant pressure dropping funnels over 3 hours. After the addition was completed, the temperature was raised to 80℃ and kept at that temperature for 2 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified phosphor.

[0020] Example 4 This embodiment provides a modified acrylic emulsion, prepared by the following method: B1. Add 25g of styrene, 30g of methyl methacrylate, 35g of butyl acrylate, 3.5g of acrylic acid, 2.5g of hydroxyethyl acrylate, 3.825g of divinylbenzene (Y=4.5%) and 3g of sodium allyl hydroxypropyl sulfonate to 120g of deionized water and emulsify at high speed for 30min to obtain a monomer pre-emulsion. B2. Heat 50g of deionized water to 80℃, then add 5% of the monomer pre-emulsion prepared in step A1 and 9g of 2wt% ammonium persulfate aqueous solution to initiate polymerization. After the emulsion turns blue, start to add the remaining monomer pre-emulsion and 171g of 2wt% ammonium persulfate aqueous solution dropwise, controlling the addition to be completed within 3 hours. After the addition is completed, raise the temperature to 85℃ and keep it at that temperature for 1 hour. Cool it down, adjust the pH to 8.5 with ammonia water, filter, and obtain the modified acrylic emulsion.

[0021] Example 5 This embodiment provides a modified acrylic emulsion, prepared by the following method: B1. Add 28g of styrene, 30g of methyl methacrylate, 32g of butyl acrylate, 3g of acrylic acid, 2g of hydroxyethyl acrylate, 5.4g of divinylbenzene (Y=6%) and 3.5g of sodium allyl hydroxypropyl sulfonate to 120g of deionized water and emulsify at high speed for 30min to obtain a monomer pre-emulsion. B2. Heat 50g of deionized water to 80℃, then add 5% of the monomer pre-emulsion prepared in step A1 and 9.5g of 2wt% ammonium persulfate aqueous solution to initiate polymerization. After the emulsion turns blue, start to add the remaining monomer pre-emulsion and 180.5g of 2wt% ammonium persulfate aqueous solution dropwise, controlling the addition to be completed within 3 hours. After the addition is completed, raise the temperature to 85℃ and keep it at that temperature for 1 hour. Cool, adjust the pH to 8.5 with ammonia water, filter, and obtain the modified acrylic emulsion.

[0022] Example 6 This embodiment provides a modified acrylic emulsion, prepared by the following method: B1. Add 30g of styrene, 30g of methyl methacrylate, 30g of butyl acrylate, 2.5g of acrylic acid, 3.5g of hydroxyethyl acrylate, 6.75g of ethylene glycol dimethacrylate (Y=7.5%) and 4g of sodium allyl hydroxypropyl sulfonate to 120g of deionized water and emulsify at high speed for 30min to obtain a monomer pre-emulsion. B2. Heat 50g of deionized water to 80℃, then add 5% of the monomer pre-emulsion prepared in step A1 and 10g of 2wt% ammonium persulfate aqueous solution to initiate polymerization. After the emulsion turns blue, start to add the remaining monomer pre-emulsion and 180g of 2wt% ammonium persulfate aqueous solution dropwise, controlling the addition to be completed within 3 hours. After the addition is completed, raise the temperature to 85℃ and keep it at that temperature for 1 hour. Cool it down, adjust the pH to 8.5 with ammonia water, filter, and obtain the modified acrylic emulsion.

[0023] Example 7 This embodiment provides a water-based fluorescent coating, comprising the following raw materials in parts by weight: 20 parts of modified fluorescent powder prepared in Example 1, 60 parts of modified acrylic emulsion prepared in Example 4, 0.5 parts of ammonium polyacrylate wetting and dispersing agent SN-5040, 0.1 parts of silicone defoamer BYK-024, 2 parts of alcohol ester twelve, 0.2 parts of polyether siloxane, 2 parts of alkali-swellable acrylic thickener ASE-60, and 10 parts of deionized water; This water-based fluorescent coating is prepared through the following steps: Modified fluorescent powder, modified acrylic emulsion, SN-5040, half of the amount of BYK-024, and deionized water were added to a high-speed disperser and mixed at 800 rpm for 20 min. Then the speed was reduced to 300 rpm, and alcohol ester dodecyl, polyether siloxane, and the remaining BYK-024 were added in sequence and stirred evenly. The pH of the system was then adjusted to 8.5 with ammonia. Finally, ASE-60 was added to adjust the viscosity. After filtration, the mixture was sealed and aged for no less than 24 h to obtain the water-based fluorescent coating.

[0024] Example 8 This embodiment provides a water-based fluorescent coating, comprising the following raw materials in parts by weight: 35 parts of modified fluorescent powder prepared in Example 2, 45 parts of modified acrylic emulsion prepared in Example 5, 1.5 parts of ammonium polyacrylate wetting and dispersing agent SN-5040, 0.5 parts of silicone defoamer BYK-024, 5 parts of alcohol ester twelve, 0.8 parts of polyether siloxane, 1 part of alkali-swellable acrylic thickener ASE-60, and 15 parts of deionized water; This water-based fluorescent coating is prepared through the following steps: Modified fluorescent powder, modified acrylic emulsion, SN-5040, half of the amount of BYK-024, and deionized water were added to a high-speed disperser and mixed at 1100 rpm for 30 min. Then the speed was reduced to 400 rpm, and alcohol ester dodecyl, polyether siloxane, and the remaining BYK-024 were added in sequence and stirred evenly. The pH of the system was then adjusted to 9.0 with ammonia. Finally, ASE-60 was added to adjust the viscosity. After filtration, the mixture was sealed and aged for no less than 24 h to obtain the water-based fluorescent coating.

[0025] Example 9 This embodiment provides a water-based fluorescent coating, comprising the following raw materials in parts by weight: 50 parts of modified fluorescent powder prepared in Example 3, 30 parts of modified acrylic emulsion prepared in Example 6, 3 parts of ammonium polyacrylate wetting and dispersing agent SN-5040, 1 part of silicone defoamer BYK-024, 8 parts of propylene glycol phenyl ether, 1.5 parts of polyether siloxane, 0.2 parts of alkali-swellable acrylic thickener ASE-60, and 30 parts of deionized water; This water-based fluorescent coating is prepared through the following steps: Modified fluorescent powder, modified acrylic emulsion, SN-5040, half of the amount of BYK-024, and deionized water were added to a high-speed disperser and mixed at 1500 rpm for 40 min. Then the speed was reduced to 500 rpm, and propylene glycol phenyl ether, polyether siloxane, and the remaining BYK-024 were added in sequence and stirred evenly. The pH of the system was then adjusted to 8.5 with ammonia water. Finally, ASE-60 was added to adjust the viscosity. After filtration, the mixture was sealed and aged for no less than 24 h to obtain the water-based fluorescent coating.

[0026] Comparative Example 1 The difference between this comparative example and Example 7 is that an untreated SrAl2O4:Eu,Dy long afterglow phosphor (average particle size of 15 μm) was used to replace the modified phosphor prepared in Example 1 in an equal amount, while the other raw materials and steps were the same.

[0027] Comparative Example 2 The difference between this comparative example and Example 7 is that a commercially available ordinary styrene-acrylic emulsion was used to replace the modified acrylic emulsion prepared in Example 4 in equal amounts, while the other raw materials and steps were the same.

[0028] Comparative Example 3 The difference between this comparative example and Example 7 is that the modified phosphor powder prepared in Example 3 is used to replace the modified phosphor powder prepared in Example 1 in an equal amount, while the other raw materials and steps are the same.

[0029] Comparative Example 4 The difference between this comparative example and Example 7 is that the modified acrylic emulsion prepared in Example 6 is used to replace the modified acrylic emulsion prepared in Example 4 in an equal amount, while the other raw materials and steps are the same.

[0030] The performance of the water-based fluorescent coatings prepared in Examples 7-9 and Comparative Examples 1-4 was tested. The water-based fluorescent coatings were applied to the surfaces of tinplate and glass plates, with the coating thickness controlled at 80 μm. The coatings were then tested after curing at room temperature for 7 days. Fluorescence intensity test: Place the cured coating test plate in a dark room, excite it with a standard D65 light source for 10 minutes, and immediately use a luminance meter to measure the luminance value 10 seconds after the excitation stops, and record it as the initial luminance (L0). Water resistance test: The coated test plate was completely immersed in deionized water at 25℃ for 168h. After soaking, it was taken out and the surface moisture was absorbed with filter paper. After recovery in a standard environment of 23±2℃ and 50±5% relative humidity for 1h, its brightness (L1) was measured according to the fluorescence intensity test method described above, and the brightness retention rate (%) was calculated according to the formula: brightness retention rate (%) = (L1 / L0) × 100%. Weather resistance test: Accelerated aging test with fluorescent ultraviolet lamp was conducted according to GB / T 23987-2009 "Artificial weathering exposure and fluorescent ultraviolet exposure of paint and varnish coatings" standard, using UVA-340 lamp tubes with an irradiance of 0.83W / m². 2 @340nm, after cycling with 60℃ UV irradiation for 4h, 50℃ condensation for 4h, and aging for 600h, its brightness (L2) was measured according to the above fluorescence intensity test method, and the brightness retention rate (%) was calculated according to the formula = (L2 / L0)×100%. Pencil hardness: Tested according to GB / T 6739-2006 "Determination of Hardness of Paint Film by Pencil Method".

[0031] Adhesion: Tested according to GB / T 9286-1998 "Cross-cut test of paint and varnish film".

[0032] The results are shown in Table 1: Table 1 Group Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 X value 3 6 10 Original powder 3 10 3 Y value 4.5 6 7.5 4.5 regular lotion 4.5 7.5 Y / X ratio 1.5 1 0.75 - - 0.45 2.5 <![CDATA[Initial brightness (mcd / m 2 )]]> 2990 3080 2960 2760 2870 2940 2950 Water immersion brightness retention rate 94% 97% 96% 42% 65% 75% 82% Brightness retention rate during aging 92% 95% 93% 36% 55% 68% 76% Pencil hardness 2H 3H 3H B B H H Adhesion Level 0 Level 0 Level 0 Level 2 Level 2 Level 2 Level 1 As shown in Table 1, Examples 7-9 (Y / X between 0.75 and 1.5) exhibited excellent overall performance, especially in water resistance (>94%) and weather resistance (>92%), and the resulting coatings also showed excellent mechanical properties. Comparative Example 1 (unmodified phosphor) and Comparative Example 2 (unmodified emulsion) showed the worst performance, proving that isolated improvements cannot solve the fundamental interfacial phase separation problem. Comparative Example 3 (Y / X=0.45) and Comparative Example 4 (Y / X=2.5) showed significantly lower performance than the examples, proving that a Y / X ratio exceeding the 0.75-1.5 range leads to poorer interfacial bonding and decreased performance. This is not a simple performance degradation, but rather demonstrates the existence of an optimal synergistic range. By limiting the ratio Y / X between the percentage of crosslinking agent in the polymer shell and the percentage of crosslinking monomer in the modified acrylic emulsion to the key synergistic range of 0.75-1.5, and combining this with the setting of functional monomers in the modified acrylic emulsion, the present invention successfully achieved interfacial integration and significantly improved the overall performance of waterborne fluorescent coatings.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-based fluorescent coating, characterized in that, Including the following parts by weight of raw materials: 20-50 parts modified fluorescent powder, 30-60 parts modified acrylic emulsion, 0.5-3 parts wetting and dispersing agent, 0.1-1 parts defoamer, 2-8 parts film-forming aid, 0.2-1.5 parts leveling agent, 0.2-2 parts thickener, and 10-30 parts deionized water; The modified phosphor is a phosphor with a polymer shell coating on its surface. The polymer shell is formed by in-situ polymerization of shell monomers, bonding monomers and crosslinking agents. The amount of shell monomers is 17-24% of the weight of the phosphor, and the amount of crosslinking agents is 3-10% of the weight of the shell monomers. This value is denoted as X. The modified acrylic emulsion is an acrylic copolymer emulsion containing a base monomer, a functional monomer, and a crosslinking monomer. The amount of the crosslinking monomer is 1.5-7.5% of the weight of the base monomer, denoted as Y, and the ratio of Y to X is 0.75-1.

5.

2. The water-based fluorescent coating according to claim 1, characterized in that, The modified phosphor powder is prepared by the following method: A1. Add the fluorescent powder and sodium dodecylbenzene sulfonate to deionized water and disperse them evenly by ultrasonication to obtain a fluorescent powder suspension; A2. After mixing the shell monomer, bonding monomer and crosslinking agent evenly, add them to deionized water containing sodium dodecyl sulfate for emulsification to obtain a shell pre-emulsion. A3. Under nitrogen protection and stirring at 70℃, the shell pre-emulsion and the first initiator solution were simultaneously and uniformly added to the phosphor suspension. After the addition was completed, the temperature was raised to 80℃ and kept at that temperature for 2 hours. After the reaction was completed, the phosphor was centrifuged, washed, and dried to obtain the modified phosphor.

3. The water-based fluorescent coating according to claim 2, characterized in that, The mass ratio of the fluorescent powder, sodium dodecylbenzenesulfonate, and deionized water is 100:2:

400.

4. The water-based fluorescent coating according to claim 2, characterized in that, The ratio of the shell monomer, bonding monomer, crosslinking agent, sodium dodecyl sulfate, and deionized water is 17-24:0.34-0.48:0.51-2.4:1:30; the shell monomer is a mixture of styrene, methyl methacrylate, and butyl acrylate in a mass ratio of 8-12:5-8:4; the bonding monomer is methacrylic acid or hydroxyethyl acrylate; and the crosslinking agent is divinylbenzene or ethylene glycol dimethacrylate.

5. The water-based fluorescent coating according to claim 2, characterized in that, The mass ratio of the shell pre-emulsion, the first initiator solution, and the phosphor suspension is 48.85-57.88:20-40:502; the first initiator solution is a 1.5wt% potassium persulfate aqueous solution.

6. The water-based fluorescent coating according to claim 1, characterized in that, The modified acrylic emulsion is prepared by the following method: B1. Add the basic monomer, functional monomer, crosslinking monomer and reactive emulsifier to deionized water for emulsification to obtain a monomer pre-emulsion; B2. Add 5% of the total mass of monomer pre-emulsion and the second initiator solution to deionized water heated to 80°C to initiate polymerization. After the emulsion turns blue, start to add the remaining monomer pre-emulsion and the second initiator solution dropwise simultaneously. After the addition is complete, raise the temperature to 85°C and keep it at that temperature for 1 hour. Cool, adjust the pH to 8.5 with ammonia water, filter, and obtain the modified acrylic emulsion.

7. The water-based fluorescent coating according to claim 6, characterized in that, The mass ratio of the base monomer, functional monomer, crosslinking monomer, reactive emulsifier, and deionized water is 90:6:3.825-6.75:3-4:120; the base monomer is a mixture of styrene, methyl methacrylate, and butyl acrylate in a mass ratio of 25-30:30:30-35; the functional monomer is a mixture of acrylic acid and hydroxyethyl acrylate in a mass ratio of 2.5-3.5:2.5-3.5; the crosslinking monomer is divinylbenzene or ethylene glycol dimethacrylate; and the reactive emulsifier is sodium allyl hydroxypropyl sulfonate.

8. The water-based fluorescent coating according to claim 6, characterized in that, The mass ratio of the monomer pre-emulsion, the second initiator solution, and deionized water is 222.825-226.75:180-200:50; the second initiator solution is a 2wt% ammonium persulfate aqueous solution.

9. The water-based fluorescent coating according to claim 1, characterized in that, The wetting and dispersing agent is an ammonium polyacrylate; the defoamer is an organosilicon; the film-forming aid is one of dodecyl alcohol ester and propylene glycol phenyl ether; the leveling agent is a polyether siloxane; and the thickener is an alkali-swellable acrylic.

10. The method for preparing an aqueous fluorescent coating according to claim 1, characterized in that, Includes the following steps: Modified fluorescent powder, modified acrylic emulsion, wetting and dispersing agent, half of the defoamer and deionized water are added to a high-speed disperser and mixed at 800-1500 rpm for 20-40 min. Then the speed is reduced to 300-500 rpm, and film-forming aid, leveling agent and the remaining defoamer are added in sequence and stirred evenly. The pH of the system is then adjusted to 8.5-9.0 with ammonia water. Finally, a thickener is added to adjust the viscosity. After filtration, the mixture is sealed and cured for no less than 24 h to obtain water-based fluorescent coating.