A long-lasting reflective coating for surface pollution meter and preparation method thereof

Abstract

The invention discloses a long-lasting reflective coating for a surface contamination meter and a preparation method thereof. The preparation method comprises the following steps: placing a substrate in an ultrasonic cleaner, ultrasonically treating it in an ethanol solution, rinsing it with clean water until no foam is generated, then cleaning it with deionized water and anhydrous ethanol, and blowing it dry with N2; using an automatic air spray gun to evenly spray the modified coating on the surface of the substrate; placing the substrate in an ultraviolet (UV) furnace for curing, and then placing it in an oven for curing, thereby obtaining a long-lasting reflective coating for a surface contamination meter; the invention effectively increases the volume fraction of the barium sulfate filler in the emulsion by modifying barium sulfate, greatly improving the multiple scattering effect of the incident light signal in the coating, and improving the reflective performance of the coating; in addition, the modified coating and the silicone acrylic emulsion synergistically increase the firmness and durability of the coating, thereby obtaining a long-lasting highly reflective coating.

Description

Technical Field

[0001] The present invention relates to the field of reflective coating preparation, and in particular to a long-lasting reflective coating for a surface contamination meter and a preparation method thereof. Background Art

[0002] At present, portable surface contamination monitors are widely used in nuclear power plants, reprocessing plants, nuclear fuel workshops and other related radioactive material users. They are used to quickly and effectively measure the α, β and γ contamination levels on the surface of objects. When the radioactive contamination exceeds a certain set value, it can immediately alarm, so that the staff can take effective measures to separate and decontaminate the pollutants, avoiding unnecessary exposure of personnel and pollution of the environment.

[0003] Radiation surface contamination detectors typically use a ZnS (Ag) coating and plastic flash probe to convert radiation signals into fluorescence. This light is then collected by a reflector and converted into an electrical signal by a photomultiplier tube. While surface contamination meters can typically have a relatively large detection area, the collection end of a photomultiplier tube is typically small. Therefore, the efficiency of the diffuse reflective layer within the reflector, which acts as an air light guide, directly determines the device's detection efficiency.

[0004] At present, whitening agent paint, zinc oxide cellulose paint, ordinary barium sulfate and Avian-B paint are generally used as spraying materials, which are sprayed inside the reflector of the equipment as a diffuse reflective layer to improve the light collection efficiency of the surface contamination meter.

[0005] Chinese patent document CN201610346918.0 discloses a diffuse reflective coating and a preparation method thereof, belonging to the field of coating technology. Its raw materials include: barium sulfate, nano-aluminum oxide, nano-magnesium oxide, and polyvinyl alcohol aqueous solution, which significantly improves the reflectivity of light; however, this existing technology has the following disadvantages: slightly low reflective efficiency, the coating is not strong enough, and it is easy to fall off. Summary of the Invention

[0006] In order to address the deficiencies in the prior art, the present invention aims to provide a long-lasting reflective coating for a surface contamination meter and a preparation method thereof, which effectively increases the volume fraction of the filler in the emulsion, greatly enhances the multiple scattering effect of the incident light signal in the coating, and improves the reflective performance of the coating; in addition, the modified coating and the silicone acrylic emulsion work together to increase the firmness and durability of the coating, thereby obtaining a long-lasting, highly reflective coating.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a long-lasting reflective coating for a surface contamination meter comprises the following steps:

[0009] The substrate is placed in an ultrasonic cleaner and ultrasonically treated in a 5-10 wt% ethanol solution at 50-60°C for 10-20 minutes. The substrate is then rinsed with clean water until no foam is generated. The substrate is then rinsed with deionized water and anhydrous ethanol and blown dry with nitrogen. The modified coating is evenly sprayed on the surface of the substrate using an automatic air spray gun. The coating film thickness is 8-20 μm. The substrate sprayed with the modified coating is placed in a UV oven for curing for 2-4 hours. The UV energy is controlled at 500-700 mJ / cm 2 , and then put it into a 60-80°C oven for curing for 8-10 hours to obtain a long-lasting reflective coating for surface pollution meter.

[0010] Preferably, the modified coating is made of the following components in parts by weight: 40-60 parts of modified barium sulfate, 40-60 parts of silicone acrylic emulsion, 10-20 parts of deionized water, 0.5-1 part of leveling agent, 1-2 parts of thickener, 1-2 parts of dispersant, and 1-3 parts of curing agent.

[0011] Preferably, the preparation method of the modified barium sulfate comprises the following steps:

[0012] (1) calcining and crushing barium sulfate, then adding it to a DMF aqueous solution, stirring it evenly, adding an acid solution thereto, stirring and mixing it evenly, ultrasonically treating it, filtering, washing, and drying it to obtain pretreated barium sulfate;

[0013] (2) Add the pretreated barium sulfate to DMF, preheat, and dropwise add 2-octenylsuccinic anhydride. After the addition is complete, keep the mixture warm for reaction. Filter the product, wash with ethanol, and dry to obtain anhydride barium sulfate. The specific reaction process is as follows:

[0014]

[0015] (3) adding anhydride-treated barium sulfate to ethylene glycol, raising the temperature, adding p-toluenesulfonic acid, and heating to react, removing water during the reaction, filtering, washing, and drying the product to obtain an intermediate; the specific reaction process is as follows:

[0016]

[0017] (4) The intermediate is dispersed in dimethyl sulfoxide, and then IPTS and dibutyltin diacetate are added, stirred for reaction, and the product is filtered, washed, and dried to obtain modified barium sulfate. The specific reaction process is as follows:

[0018]

[0019] Preferably, in step (1), the barium sulfate is 1500-2000 mesh; the calcination conditions are 800-850° C. for 30-50 min; the ultrasonic treatment time is 10-20 min; and the product is dried to a moisture content of <3%.

[0020] Preferably, in step (1), the mass fraction of the DMF aqueous solution is 25-35wt%, the acid solution is a mixture of 5-10wt% nitric acid solution and 10-15wt% acetic acid solution in a volume ratio of 1:1-2; the weight ratio of barium sulfate, DMF aqueous solution, and acid solution is 10:20-30:50-60.

[0021] Preferably, in step (2), the weight ratio of pretreated barium sulfate, DMF, and 2-octenylsuccinic anhydride is 10:40-60:12.1-16.7.

[0022] Preferably, in step (2), the preheating temperature is 50-70° C., 1-2 drops of 2-octenylsuccinic anhydride are added dropwise, and the reaction conditions are stirring at 60-70° C. for 3-5 hours.

[0023] Preferably, in step (3), the weight ratio of anhydride barium sulfate, ethylene glycol, and p-toluenesulfonic acid is 11.4-12.6:30-50:0.2-0.6; the temperature is raised to 60-80°C, and the heating reaction conditions are 110-130°C for 1-2 hours.

[0024] Preferably, in step (4), the weight ratio of the intermediate, dimethyl sulfoxide, IPTS, and dibutyltin diacetate is 10:80-100:4-12:0.05-0.2; and the stirring reaction conditions are 50-80° C. and the reaction is carried out for 8-12 hours.

[0025] Preferably, the preparation method of the modified coating comprises the following steps: adding modified barium sulfate to a silicone acrylic emulsion, then adding deionized water, a leveling agent, a thickener, a dispersant, and a curing agent, and mixing them uniformly to obtain a modified coating.

[0026] Preferably, the leveling agent is BYK-300, the thickener is carboxymethyl cellulose, the dispersant is BYK-P104, and the curing agent is the light curing agent benzophenone.

[0027] The present invention also claims protection for a long-lasting reflective coating for a surface contamination meter prepared by the preparation method.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) The present invention provides a long-lasting reflective coating for a surface contamination meter, which is prepared from a modified coating. The modified coating uses a silicone-acrylic emulsion and modified barium sulfate particles as raw materials. The reflectivity of the silicone-acrylic emulsion matrix is ​​about 1.5, and the refractive index of the barium sulfate itself differs greatly from that of the matrix, which can produce multiple scattering of light signals to obtain high reflectivity. The present invention modifies the barium sulfate particles so that the inorganic filler is uniformly dispersed in the silicone-acrylic emulsion matrix, effectively increasing the volume fraction of the filler in the emulsion, greatly improving the multiple scattering effect of the incident light signal in the coating, and improving the reflective performance of the coating. In addition, the modified coating and the silicone-acrylic emulsion work together to increase the firmness and durability of the coating, thereby obtaining a long-lasting, highly reflective coating.

[0030] 2) The present invention provides a modified barium sulfate, which comprises the following steps: first, calcining and acid-treating the barium sulfate to increase the active groups on the surface of the barium sulfate to obtain pretreated barium sulfate; then, reacting 2-octenylsuccinic anhydride with the barium sulfate to consume the hydrophilic hydroxyl groups on the surface of the barium sulfate, introducing double bonds, carboxyl groups and long fatty chains on the surface of the barium sulfate, and effectively improving the lipophilicity of the barium sulfate to obtain anhydride-modified barium sulfate; then, using ethylene glycol as a cross-linking agent, introducing active hydroxyl groups through an esterification reaction to obtain an intermediate; finally, using dibutyltin diacetate as a catalyst, causing the isocyanate groups in the isocyanate-silane coupling agent IPTS to preferentially react with the active hydroxyl groups in the intermediate to obtain a silane-modified barium sulfate. Modified barium sulfate modified with a coupling agent; the modified barium sulfate is compounded with a silicone-acrylic emulsion and coated on a substrate. The siloxane on the surface of the modified barium sulfate can undergo a condensation reaction with the hydroxyl groups on the surface of the substrate after hydrolysis to form a strong Si-O-Si chemical bond, which has a good fixing effect, thereby enhancing the mechanical strength of the coating and obtaining a long-lasting and durable reflective coating; in addition, the double bond functional groups introduced on the surface of the barium sulfate by 2-octenylsuccinic anhydride can subsequently undergo UV polymerization reaction with the unsaturated monomers in the silicone-acrylic emulsion under the action of ultraviolet light, thereby improving the cross-linking degree and mechanical properties of the coating itself, ensuring that the coating does not fall off for a long time, and improving the durability of the coating.

[0031] 3) The present invention provides a modified barium sulfate. The inventors have found through multiple experiments that the key to the preparation of the modified barium sulfate is that when the pretreated barium sulfate is subjected to organic treatment with 2-octenylsuccinic anhydride in step (2), the 2-octenylsuccinic anhydride must be slightly excessive to effectively consume the hydrophilic hydroxyl groups on the surface of the barium sulfate. In this way, the isocyanate groups of IPTS in the subsequent step (4) can preferentially react with the active hydroxyl groups of the intermediate, thereby reducing the side reaction of condensation between the siloxane in IPTS and the hydroxyl groups on the surface of the barium sulfate. However, if the amount of 2-octenylsuccinic anhydride exceeds a certain value, it will also affect the yield of the reaction in step (4). Therefore, the weight ratio of the pretreated barium sulfate to 2-octenylsuccinic anhydride in step (2) should be controlled within a certain range. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0033] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from commercially purchased raw materials.

[0034] The silicone acrylic emulsion model is SD-528.

[0035] The present invention will be further described below with reference to specific examples.

[0036] Example 1

[0037] A method for preparing a modified coating comprises the following steps:

[0038] (1) 10 g of barium sulfate was calcined at 850° C. for 50 min, crushed, and then added to 30 g of a 30 wt% DMF aqueous solution and stirred uniformly. 60 g of an acid solution (a mixture of 10 wt% nitric acid solution and 15 wt% acetic acid solution in a volume ratio of 1:1) was added thereto, stirred and mixed uniformly, ultrasonically treated for 20 min, filtered, washed, and dried to a water content of <3% to obtain pretreated barium sulfate;

[0039] (2) Add 10 g of pretreated barium sulfate to 60 g of DMF, preheat to 70° C., and add 16.7 g of 2-octenylsuccinic anhydride dropwise over 2 h. After the addition is complete, stir and react at 70° C. for 5 h. Filter the product, wash with ethanol three times, and dry to obtain anhydride barium sulfate.

[0040] (3) Add 12.6 g of anhydride-treated barium sulfate to 50 g of ethylene glycol, heat to 80°C, add 0.6 g of p-toluenesulfonic acid, and react at 130°C for 2 h. During this time, remove water, filter, wash, and dry the product to obtain an intermediate.

[0041] (4) Disperse 10 g of the intermediate in 100 g of dimethyl sulfoxide, then add 12 g of IPTS and 0.2 g of dibutyltin diacetate, and stir at 80° C. for 12 h. Filter, wash, and dry the product to obtain modified barium sulfate.

[0042] (5) Add 60 g of modified barium sulfate to 60 g of silicone acrylic emulsion, then add 15 g of deionized water, 1 g of leveling agent, 1 g of thickener, 2 g of dispersant, and 3 g of curing agent, mix well, and obtain a modified coating.

[0043] Example 2

[0044] A method for preparing a modified coating comprises the following steps:

[0045] (1) 10 g of barium sulfate was calcined at 800° C. for 30 min, crushed, and then added to 20 g of a 30 wt% DMF aqueous solution and stirred uniformly. 50 g of an acid solution (a mixture of 10 wt% nitric acid solution and 15 wt% acetic acid solution in a volume ratio of 1:1) was added thereto, stirred and mixed uniformly, ultrasonically treated for 10 min, filtered, washed, and dried to a water content of <3% to obtain pretreated barium sulfate;

[0046] (2) Add 10 g of pretreated barium sulfate to 40 g of DMF, preheat to 50° C., and add 12.1 g of 2-octenylsuccinic anhydride dropwise over 1 hour. After the addition is complete, stir and react at 60° C. for 3 hours. Filter the product, wash with ethanol three times, and dry to obtain anhydride barium sulfate.

[0047] (3) Add 11.4 g of anhydride-treated barium sulfate to 30 g of ethylene glycol, heat to 60°C, add 0.2 g of p-toluenesulfonic acid, and react at 110°C for 1 h. During this time, remove water, filter, wash, and dry the product to obtain an intermediate.

[0048] (4) Disperse 10 g of the intermediate in 80 g of dimethyl sulfoxide, then add 4 g of IPTS and 0.05 g of dibutyltin diacetate, and stir at 50 °C for 8 h. Filter, wash, and dry the product to obtain modified barium sulfate.

[0049] (5) Add 40 g of modified barium sulfate to 60 g of silicone acrylic emulsion, then add 15 g of deionized water, 1 g of leveling agent, 1 g of thickener, 2 g of dispersant, and 3 g of curing agent, mix well, and obtain a modified coating.

[0050] Example 3

[0051] A method for preparing a modified coating comprises the following steps:

[0052] (1) 10 g of barium sulfate was calcined at 830° C. for 40 min, crushed, and then added to 25 g of a 30 wt % DMF aqueous solution and stirred uniformly. 55 g of an acid solution (a mixture of 10 wt % nitric acid solution and 15 wt % acetic acid solution in a volume ratio of 1:1) was added thereto, stirred and mixed uniformly, ultrasonically treated for 15 min, filtered, washed, and dried to a water content of <3% to obtain pretreated barium sulfate;

[0053] (2) Add 10 g of pretreated barium sulfate to 50 g of DMF, preheat to 60° C., and add 14.5 g of 2-octenylsuccinic anhydride dropwise over 1.5 hours. After the addition is complete, stir and react at 65° C. for 4 hours. Filter the product, wash with ethanol three times, and dry to obtain anhydride barium sulfate.

[0054] (3) Add 12 g of anhydride-treated barium sulfate to 40 g of ethylene glycol, heat to 70°C, add 0.4 g of p-toluenesulfonic acid, and react at 120°C for 1.5 h, during which time water is removed. The product is filtered, washed, and dried to obtain an intermediate;

[0055] (4) Disperse 10 g of the intermediate in 90 g of dimethyl sulfoxide, then add 8 g of IPTS and 0.1 g of dibutyltin diacetate, and stir the mixture at 60° C. for 10 h. Filter, wash, and dry the product to obtain modified barium sulfate.

[0056] (5) Add 50 g of modified barium sulfate to 60 g of silicone acrylic emulsion, then add 15 g of deionized water, 1 g of leveling agent, 1 g of thickener, 2 g of dispersant, and 3 g of curing agent, mix well, and obtain a modified coating.

[0057] Example 4

[0058] A method for preparing a long-lasting reflective coating for a surface contamination meter comprises the following steps:

[0059] The substrate was placed in an ultrasonic cleaner and ultrasonically treated in a 5 wt% ethanol solution at 55°C for 15 min. The substrate was rinsed with clean water until no foam was generated. The substrate was then rinsed with deionized water and anhydrous ethanol three times each and dried with N2. The modified coating prepared in Example 1 was evenly sprayed on the surface of the substrate using an automatic air spray gun. The coating film thickness was 15 μm. The substrate sprayed with the modified coating was placed in an ultraviolet UV oven for curing for 3 h. The ultraviolet energy was controlled at 600 mJ / cm 2 , and then put it into an 80℃ oven for curing for 9 hours to obtain a long-lasting reflective coating for surface pollution meter.

[0060] Example 5

[0061] A method for preparing a long-lasting reflective coating for a surface contamination meter comprises the following steps:

[0062] The substrate was placed in an ultrasonic cleaner and ultrasonically treated in a 5 wt% ethanol solution at 55°C for 15 min. The substrate was rinsed with clean water until no foam was generated. The substrate was then rinsed with deionized water and anhydrous ethanol three times each and dried with N2. The modified coating prepared in Example 2 was evenly sprayed on the surface of the substrate using an automatic air spray gun. The coating film thickness was 15 μm. The substrate sprayed with the modified coating was placed in an ultraviolet UV oven for curing for 3 h. The ultraviolet energy was controlled at 600 mJ / cm 2, and then put it into an 80℃ oven for curing for 9 hours to obtain a long-lasting reflective coating for surface pollution meter.

[0063] Example 6

[0064] A method for preparing a long-lasting reflective coating for a surface contamination meter comprises the following steps:

[0065] The substrate was placed in an ultrasonic cleaner and ultrasonically treated in a 5 wt% ethanol solution at 55°C for 15 min. The substrate was rinsed with clean water until no foam was generated. The substrate was then rinsed with deionized water and anhydrous ethanol three times each and dried with N2. The modified coating prepared in Example 3 was evenly sprayed on the surface of the substrate using an automatic air spray gun. The coating film thickness was 15 μm. The substrate sprayed with the modified coating was placed in an ultraviolet UV oven for curing for 3 h. The ultraviolet energy was controlled at 600 mJ / cm 2 , and then put it into an 80℃ oven for curing for 9 hours to obtain a long-lasting reflective coating for surface pollution meter.

[0066] Comparative Example 1

[0067] A method for preparing a coating comprises the following steps:

[0068] (1) 10 g of barium sulfate was calcined at 850° C. for 50 min, crushed, and then added to 30 g of a 30 wt% DMF aqueous solution and stirred uniformly. 60 g of an acid solution (a mixture of 10 wt% nitric acid solution and 15 wt% acetic acid solution in a volume ratio of 1:1) was added thereto, stirred and mixed uniformly, ultrasonically treated for 20 min, filtered, washed, and dried to a water content of <3% to obtain pretreated barium sulfate;

[0069] (2) Add 10 g of pretreated barium sulfate to 60 g of DMF, preheat to 70° C., and add 16.7 g of 2-octenylsuccinic anhydride dropwise over 2 h. After the addition is complete, stir and react at 70° C. for 5 h. Filter the product, wash with ethanol three times, and dry to obtain anhydride barium sulfate.

[0070] (3) Add 60 g of anhydride-treated barium sulfate to 60 g of silicone acrylic emulsion, then add 15 g of deionized water, 1 g of leveling agent, 1 g of thickener, 2 g of dispersant, and 3 g of curing agent, mix well, and obtain a coating.

[0071] Comparative Example 2

[0072] A method for preparing a coating comprises the following steps:

[0073] (1) 10 g of barium sulfate was calcined at 850° C. for 50 min, crushed, and then added to 30 g of a 30 wt% DMF aqueous solution and stirred uniformly. 60 g of an acid solution (a mixture of 10 wt% nitric acid solution and 15 wt% acetic acid solution in a volume ratio of 1:1) was added thereto, stirred and mixed uniformly, ultrasonically treated for 20 min, filtered, washed, and dried to a water content of <3% to obtain pretreated barium sulfate;

[0074] (2) 60 g of pretreated barium sulfate was added to 60 g of silicone acrylic emulsion, and then 15 g of deionized water, 1 g of leveling agent, 1 g of thickener, 2 g of dispersant, and 3 g of curing agent were added and mixed evenly to obtain a coating.

[0075] The coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to performance tests. The cross-cut adhesion of the coating was determined with reference to GB / T 9286-2021 "Scratch Test for Paints and Varnishes", the pull-off adhesion of the coating was determined with reference to GB / T 5210-2006 "Pull-off Adhesion Test for Paints and Varnishes", the impact resistance of the coating was determined with reference to GB / T 1732-2020 "Determination of Impact Resistance of Paint Films", and the pencil hardness of the coating was determined with reference to GB / T 6739-2022 "Determination of Hardness of Paint Films by Pencil Method for Paints and Varnishes". The diffuse reflectance of the coating formed on the substrate was measured using a spectrophotometer (the specific test conditions were: at a wavelength of 300 to 800 nm and an interval of 1 nm, the diffuse reflectance of only the diffuse reflection component was measured by removing the specular reflected light, and the average of the measured values ​​obtained at a wavelength of 360 to 760 nm was calculated as the diffuse reflectance in the visible light region). The specific data are shown in Table 1.

[0076] Table 1 Coating performance test data

[0077]

[0078] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a long-lasting reflective coating for a surface contamination meter, characterized in that: The steps include: The substrate was placed in an ultrasonic cleaner and ultrasonically treated in a 5-10 wt% ethanol solution at 50-60°C for 10-20 minutes. The substrate was then rinsed with clean water until no foam was generated. The substrate was then rinsed with deionized water and anhydrous ethanol and dried with nitrogen. The modified coating was evenly sprayed on the surface of the substrate using an automatic air spray gun. The coating thickness was 8-20 μm. The substrate sprayed with the modified coating was placed in a UV oven for curing for 2-4 hours. The UV energy was controlled at 500-700 mJ / cm 2 , and then put it into a 60~80℃ oven for curing for 8~10h to obtain a long-lasting reflective coating for surface pollution meter; The modified coating is made of the following components in parts by weight: 40-60 parts of modified barium sulfate, 40-60 parts of silicone acrylic emulsion, 10-20 parts of deionized water, 0.5-1 part of leveling agent, 1-2 parts of thickener, 1-2 parts of dispersant, and 1-3 parts of curing agent; The silicone acrylic emulsion model is SD-528; The preparation method of the modified barium sulfate comprises the following steps: (1) calcining and crushing barium sulfate, then adding it to a DMF aqueous solution, stirring it evenly, adding an acid solution thereto, stirring and mixing it evenly, ultrasonically treating it, filtering, washing, and drying it to obtain pretreated barium sulfate; (2) adding the pretreated barium sulfate to DMF, preheating, and adding 2-octenylsuccinic anhydride dropwise. After the addition is complete, the mixture is kept warm for reaction. The product is filtered, washed with ethanol, and dried to obtain anhydride-treated barium sulfate. (3) Adding anhydride-treated barium sulfate to ethylene glycol, raising the temperature, adding p-toluenesulfonic acid, and heating to react, removing water during the reaction, filtering, washing, and drying the product to obtain an intermediate; (4) Dispersing the intermediate in dimethyl sulfoxide, then adding IPTS and dibutyltin diacetate, stirring to react, filtering, washing, and drying the product to obtain modified barium sulfate; In step (2), the weight ratio of pretreated barium sulfate, DMF, and 2-octenylsuccinic anhydride is 10:40~60:12.1~16.

7.

2. The preparation method according to claim 1, characterized in that In step (1), the barium sulfate has a mesh size of 1500-2000; the calcination conditions are calcination at 800-850° C. for 30-50 min; the ultrasonic treatment time is 10-20 min; and the product is dried to a moisture content of <3%.

3. The preparation method according to claim 1, characterized in that In step (1), the mass fraction of the DMF aqueous solution is 25-35 wt%, the acid solution is a mixture of 5-10 wt% nitric acid solution and 10-15 wt% acetic acid solution in a volume ratio of 1:1-2; the weight ratio of barium sulfate, DMF aqueous solution, and acid solution is 10:20-30:50-60.

4. The preparation method according to claim 1, characterized in that In step (2), the preheating temperature is 50-70°C, 1-2 drops of 2-octenylsuccinic anhydride are added, and the reaction conditions are stirring at 60-70°C for 3-5 hours.

5. The preparation method according to claim 1, characterized in that In step (3), the weight ratio of anhydride barium sulfate, ethylene glycol, and p-toluenesulfonic acid is 11.4-12.6:30-50:0.2-0.6; the temperature is raised to 60-80°C, and the heating reaction conditions are 110-130°C for 1-2 hours.

6. The preparation method according to claim 1, characterized in that In step (4), the weight ratio of the intermediate, dimethyl sulfoxide, IPTS, and dibutyltin diacetate is 10:80-100:4-12:0.05-0.2; and the stirring reaction conditions are 50-80° C. and the reaction is carried out for 8-12 hours.

7. A long-lasting reflective coating for surface contamination meter prepared by the preparation method according to any one of claims 1 to 6.

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