Flexible nuclear radiation protection material based on multi-layer coating structure and preparation method

Abstract

The invention relates to the technical field of nuclear radiation safety protection, and discloses a flexible nuclear radiation protection material based on a multi-layer coating structure and a preparation method. According to the protective material, a fabric is used as a base material, and oily polyurethane containing modified composite shielding powder is used as a protective coating; the composite shielding powder is formed by compounding aluminum oxide, boron carbide and one or more of oxides of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium or ytterbium or enriched substances of the oxides and the enriched substances of the oxides according to a proportion, and the particle size of the composite shielding powder is 200-500 meshes. The preparation process comprises the following steps: uniformly coating the oily polyurethane protective coating on the surface of the fabric, and after curing treatment, forming a tightly combined protective coating by the coating and a fabric substrate, thereby realizing efficient synergistic shielding of nuclear radiation rays. The protective material prepared by the preparation method disclosed by the invention has the characteristics of flexibility, flexibility and high radiation shielding effectiveness, is simple and convenient in production process and controllable in cost, is suitable for various scenes such as human body wearing protection, equipment surface protection and the like, and has relatively high practical value and popularization prospect.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation safety protection technology, and in particular to a flexible nuclear radiation protection material based on a multi-layer coating structure and its preparation method. Background Technology

[0002] With the rapid development of nuclear power generation, nuclear medicine diagnosis and treatment, nuclear industry non-destructive testing and aerospace nuclear radiation environment, the potential threat of nuclear radiation (such as X-rays, gamma rays and neutron rays) to personnel health and equipment safety is becoming increasingly prominent, and efficient and reliable nuclear radiation protection materials have become an industry necessity.

[0003] Traditional nuclear radiation protection materials are mainly composed of high-density metals such as lead plates and tungsten blocks. While they can effectively attenuate nuclear radiation due to their high atomic number and high density, they have significant drawbacks: they are rigid but inflexible, making them unsuitable for human wear (such as protective aprons and gloves), curved equipment (such as probes for nuclear medical instruments), and confined spaces, resulting in extremely low flexibility in use. Moreover, lead materials are toxic due to heavy metals, and their production, use, and disposal can easily cause soil and water pollution, which does not comply with environmental regulations and the trend of green industry development. In addition, the high density of metal materials can easily increase the overall weight of protective equipment or devices, making them particularly unsuitable for scenarios with strict load limits, such as aerospace.

[0004] To address these issues, the industry has gradually developed flexible nuclear radiation protection materials, typically prepared by combining radiation shielding powders (such as lead oxide, barium sulfate, and borides) with flexible polymer matrices (such as rubber, polyurethane, and polyvinyl chloride). While these materials possess a degree of flexibility, they still face several technical bottlenecks: First, to achieve the desired protective effect, a high proportion of shielding powder (often exceeding 60% by mass) must be added, leading to deterioration of the material's mechanical properties, making it prone to cracking, delamination, and a significantly shortened service life. Second, the poor compatibility between the shielding powder and the polymer matrix causes agglomeration during mixing, affecting not only the surface smoothness and processability of the material but also resulting in uneven protective performance and creating localized weak points. Third, existing materials are mostly designed for single types of nuclear radiation (such as protection against only X / γ rays), making it difficult to cope with the complex scenarios of multiple radiation sources coexisting in the nuclear industry and nuclear medicine, thus limiting their applicability.

[0005] Meanwhile, in scenarios such as nuclear emergency response and protection of mobile nuclear equipment, materials are required to possess weather resistance, tensile strength, and rapid packing capabilities. Existing flexible materials often struggle to balance protective performance, mechanical stability, and ease of use, failing to meet diverse nuclear radiation protection needs. Therefore, developing a flexible, lightweight protective material with good broad-spectrum nuclear radiation shielding effect, stable mechanical properties, and environmental friendliness has become a key direction for overcoming current technological bottlenecks and promoting the upgrading of the field of flexible nuclear radiation protective materials. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a flexible nuclear radiation protection material based on a multi-layer coating structure and its preparation method. The nuclear radiation protection material is flexible and lightweight, has a good comprehensive nuclear radiation shielding effect, stable mechanical properties, and is environmentally friendly.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a flexible nuclear radiation protection material based on a multi-layer coating structure, comprising:

[0008] Fabric base fabric;

[0009] A multi-layer protective coating is applied to the surface of the fabric base; and

[0010] A functional film is adhered to the outer surface of the fabric substrate after the protective coating has been applied;

[0011] The protective coating comprises the following components in parts by weight: 10-80 parts of oil-based polyurethane resin, 5-10 parts of dispersant, 10-15 parts of defoamer, 5-10 parts of coupling agent, 5-15 parts of leveling agent, 100-300 parts of N,N-dimethylformamide, and 100-600 parts of modified composite shielding powder.

[0012] The modified composite shielding powder comprises: a mixed shielding powder and a functional core-shell powder treated with a coupling agent, wherein the coupling agent accounts for 0.5%-5.0% of the total mass of the mixed shielding powder and the functional core-shell powder. Further, the mixed shielding powder is one or more of the following: alumina, boron carbide, and oxides or enrichments of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium, or ytterbium, with a particle size of 200-500 mesh.

[0013] In a preferred embodiment of the present invention, the functional core-shell powder consists of an inner core component and an outer shell component; the core component is boron carbide particles or boron-rich particles. 10 Compound B particles, with a particle size of less than 15 μm, are used for efficient absorption of thermal neutrons. The shell component is formed by coating the surface of the core component. The shell component is bismuth oxide nanoparticles or bismuth tungstate nanoparticles with a coating thickness of 80 nm-150 nm. The shell component is mainly used to absorb secondary gamma rays generated by the neutron capture reaction of the core component.

[0014] In a preferred embodiment of the present invention, the coupling agent is one of aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, and isopropoxytitanate coupling agents.

[0015] In a preferred embodiment of the present invention, the dispersant is one of phosphate ester dispersants, polyamide wax dispersants, polyurethane dispersants, and KMT-310 dispersant.

[0016] In a preferred embodiment of the present invention, the defoamer is one of the following: silicone defoamer, modified polysiloxane defoamer, and polyurethane defoamer.

[0017] In a preferred embodiment of the present invention, the leveling agent is one of silicone leveling agents, acrylate leveling agents, and fluorocarbon leveling agents.

[0018] In a preferred embodiment of the present invention, the functional film is one of polyethylene film, polypropylene film, polyester film, nylon film, and silica film.

[0019] A method for preparing a flexible nuclear radiation protection material based on a multilayer coating structure includes the following steps:

[0020] S1. Weigh the mixed shielding powder and functional core-shell powder according to the mass ratio, mix them, add them to a mixed solution of coupling agent and toluene, stir at 75℃~85℃ for 1.5h~2h, vacuum dry and sieve to obtain modified composite shielding powder;

[0021] S2. Take oil-based polyurethane resin, add modified composite shielding powder, dispersant, defoamer, coupling agent, and leveling agent, stir at high speed for 50 min to 70 min, then add N,N-dimethylformamide to adjust the viscosity, continue stirring for 15 min to 30 min, and obtain the protective coating after filtration through a sieve.

[0022] S3. Lay the pretreated fabric base flat, apply the protective coating to the surface of the fabric base and dry it to obtain the coated fabric.

[0023] S4. The functional film is bonded to the outer surface of the coated fabric by hot pressing, and then aligned and sealed to obtain a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0024] In a preferred embodiment of the present invention, the method for preparing the functional core-shell powder includes the following steps:

[0025] S11. Disperse the nuclear component precursor in a solvent;

[0026] S12. Add the shell component precursor to the solution of S11, and grow the shell component uniformly on the surface of the core component by chemical precipitation, atomic layer deposition or hydrothermal synthesis to obtain the core-shell material.

[0027] S13. The core-shell material is separated, washed, dried and pulverized to obtain functional core-shell powder with a particle size <25μm and regular morphology.

[0028] In a preferred embodiment of the present invention, the pretreatment of the fabric base includes: soaking the desired fabric in a 4% sodium hydroxide solution at 50°C for 30 minutes, rinsing it with water and drying it at 85°C, spraying it with a mixture of coupling agent and ethanol, and curing it at 70°C for 1 hour.

[0029] In a preferred embodiment of the present invention, the protective coating prepared in S2 includes: a first coating mainly composed of functional core-shell powder, and a second coating entirely composed of mixed shielding powder; in the modified composite shielding powder of the first coating, the mass ratio of functional core-shell powder to mixed shielding powder is 1:0.8-1.

[0030] In a preferred embodiment of the present invention, before coating the first coating, a pore-forming agent is slowly added to the first coating and stirred at low speed for 5-10 minutes; wherein the pore-forming agent accounts for 0.5%-3.0% of the total mass of the functional core-shell powder.

[0031] In a preferred embodiment of the present invention, the pore-forming agent is micron-sized ammonium bicarbonate particles with a particle size of 20μm-50μm or low-boiling-point solvent microcapsules.

[0032] In a preferred embodiment of the present invention, during the coating process of S3, a second coating is used to prepare a coating on one or both sides of the first coating.

[0033] In a preferred embodiment of the present invention, the drying process of S3 includes:

[0034] Pre-dry at a low temperature of 60-80℃ for 8-15 minutes for the initial cross-linking process;

[0035] Rapidly raise the temperature to 90-95℃ and hold for 5-10 minutes to allow the pore-forming agent to volatilize and micropores to form.

[0036] Curing at a high temperature of 120-180℃ for 10-20 minutes completely cross-links and fixes the micropore shape.

[0037] In a preferred embodiment of the present invention, the drying stage of pore-forming agent volatilization and micropore formation is eliminated during the drying process of the second coating.

[0038] In a preferred embodiment of the present invention, the total mass ratio of N,N-dimethylformamide in S2 to the mixed shielding powder and the functional core-shell powder is 1:4-2, and the viscosity of the protective coating is 8000-15000 mPa·s.

[0039] In a preferred embodiment of the present invention, the hot pressing method in step S4 includes the following steps:

[0040] S41. Lay the functional film on the upper and lower molds of the hot press mold and align the positioning marks;

[0041] S42. Place the coated fabric in the center of the mold, ensuring the film is wrinkle-free and without misalignment, and align the edge of the film with the mold sealing groove.

[0042] S43. Start the hot press equipment, and slowly lower the upper mold to apply a low pressure of 0.1-0.2MPa to the functional film and coated fabric to make them initially bonded together, while expelling the interlayer air, and hold for 5-10 seconds.

[0043] S44. Increase the pressure to 0.3-2MPa, while the mold continues to heat, so that the film is fully softened and the edges of the film and the coated fabric are pressed together to form a sealed structure. Maintain the set pressure holding time for 30 minutes.

[0044] S45. After the pressure holding is completed, the heating module is turned off, and cooling water is circulated through the built-in cooling water channel of the mold. When the temperature reaches the standard, the upper mold is moved upward and reset. The sealed material is removed from the mold using a special tool to obtain a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0045] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0046] (1) This invention provides a flexible nuclear radiation protection material based on a multi-layer coating structure, which has excellent durability and is very stable against ultraviolet light, gamma rays and neutron rays. After irradiation, its strength and modulus remain basically unchanged. The dense cross-linked structure of the coating can block the penetration of chemical media. At the same time, the polyurethane resin is stable against most acids, alkalis and solvents, and can be used as a structural shielding material for long-term use.

[0047] (2) The present invention uses shielding powder modified by coupling agent, which is tightly bonded to polyurethane resin through chemical bonds / hydrogen bonds and uniformly distributed in the three-dimensional cross-linked network formed by curing, without obvious agglomeration or voids. The radiation needs to pass through the continuous "powder-resin" composite structure, and the scattering / absorption probability is significantly improved. Moreover, the lead-free design avoids the harm of lead toxicity to the human body and the environment. After the fabric base is modified by alkaline hydrolysis and coupling agent, it forms a "chemical bond connection" with polyurethane resin rather than a simple physical attachment. Combined with the elasticity of the resin's own three-dimensional cross-linked structure, the material has both flexibility (fiber toughness of the fabric base) and tensile / wear resistance, solving the problem of traditional rigid protective materials being easy to break and difficult to bend.

[0048] (3) This invention employs a multi-layer coating structure, using fabric as the substrate, coating a protective coating comprising modified composite shielding powder and functional core-shell powder, and then hot-pressing a functional film. The functional core-shell powder consists of a core component (e.g., boron carbide) and a shell component (e.g., bismuth oxide). The core component efficiently absorbs thermal neutrons, while the shell component absorbs secondary gamma rays generated by neutron capture in situ. Through this unique core-shell structure, simultaneous shielding of neutrons and gamma rays is achieved, preventing secondary radiation escape and significantly improving the overall radiation shielding efficiency of the material. It also exhibits highly efficient attenuation capabilities for various types of radiation in complex radiation environments. In contrast, traditional flexible protective materials often target only a single type of radiation, and secondary gamma rays easily escape during neutron shielding, leading to incomplete protection or the need for increased thickness compensation.

[0049] (4) This invention achieves nuclear radiation protection through a combined design of modified composite shielding powder, polyurethane coating, and hot-pressing molding, without using lead materials throughout the process. Combined with the hot-pressing process, the functional film and coating form a sealed interface, which can block the contact between water vapor, oxygen and the polyurethane cross-linked structure in the coating, avoiding structural failure caused by resin hydrolysis and powder oxidation, and extending the service life of the material. At the same time, there is no solvent residue, reducing the inducement for chemical degradation inside the coating. The final product has the characteristics of being "lightweight" and "flexible", solving the portability and applicability problems of traditional rigid / heavy protective materials, avoiding the toxicity of lead and environmental pollution, and meeting environmental protection and safety requirements.

[0050] (5) In this invention, a pore-forming agent is introduced into the coating containing functional core-shell powder, and a uniform microporous structure is formed through a multi-stage drying process. These micropores, acting as "radiation scattering enhancement cavities," extend the propagation path of gamma rays and increase their interaction opportunities with the shielding powder and functional core-shell powder. At the same time, the micropores can also disperse stress when the material is bent. This improves the shielding effectiveness against gamma rays and significantly enhances the flexibility and resistance to brittle fracture of the material. Compared with existing flexible materials that often sacrifice flexibility in pursuit of high shielding efficiency, resulting in inconvenience in use or a decline in mechanical properties, the microporous structure of this invention helps to reduce the weight of the coating, maintain overall lightweight, and, combined with the hot-press sealing of the functional film, blocks the penetration of water vapor and oxygen, avoids resin hydrolysis and powder oxidation, and extends the service life of the material in humid or chemical environments, enabling it to maintain stable performance under harsh conditions such as nuclear power plant operation and maintenance and aerospace. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 These are the mass decay coefficients and K-absorption edges of each element in the preferred embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the multi-layer structure of the protective material according to a preferred embodiment of the present invention;

[0054] Figure 3 This is a schematic diagram of the protective material coating structure according to a preferred embodiment of the present invention;

[0055] Figure 4 This is a physical diagram of a preferred embodiment of the present invention. Detailed Implementation

[0056] The mainstream development direction of flexible nuclear radiation protection materials mostly adopts polymer-based composite material systems. This involves uniformly dispersing or layering heavy metal or light element compound powders with specific shielding functions within a flexible polymer matrix to achieve comprehensive protection against different types of radiation. For example, for X-ray and gamma-ray protection, elements or their compounds with high atomic numbers (high Z), such as oxides of lead, tungsten, and bismuth, are often selected to achieve efficient attenuation using the photoelectric effect and Compton scattering principle. For neutron radiation protection, the trend is towards introducing materials rich in light elements, especially those with high neutron absorption cross sections (such as boron, lithium, or their carbides). Fast neutrons are slowed down through elastic scattering, and thermal neutrons are absorbed through capture reactions.

[0057] However, neutron capture reactions are often accompanied by the generation of secondary gamma rays with specific energies. These secondary gamma rays are generated inside the coating and emitted outward in an isotropic manner. Since the thickness of a single layer of flexible protective material is usually limited, and the propagation path of secondary gamma rays may be short, if their generation location is close to or exactly on the bottom surface of the coating (the side closer to the fabric), these secondary gamma rays will not be fully absorbed and will escape from the material surface, resulting in a decrease in protective efficiency and requiring additional coating thickness to compensate. This, in turn, contradicts the technical contradiction between the original intention of lightweight and flexible material design.

[0058] Based on the above findings, the applicant proposed a flexible nuclear radiation protection material based on a multilayer coating structure. By introducing special functional core-shell powder and microporous confinement structure into the flexible polymer-based protective coating, the material achieves efficient "in-situ" absorption and scattering enhancement of secondary gamma rays captured by neutrons, significantly improving the overall protective performance of the material and allowing for overall coating thinning while maintaining or improving the protective efficiency.

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0061] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0062] This invention provides a method for preparing a flexible nuclear radiation protection material based on a multilayer coating structure, comprising the following steps:

[0063] Step S1: Weigh the mixed shielding powder and functional core-shell powder according to the mass ratio, mix them, and add them to a mixed solution of coupling agent and toluene with a mass fraction of 1.5%-5%. Stir at 75℃-85℃ for 1.5h-2h, vacuum dry at 85℃ for 2.5h, and pass through a 200-500 mesh sieve to obtain the modified composite shielding powder.

[0064] The modified composite shielding powder in this step includes: a mixed shielding powder and a functional core-shell powder treated with a coupling agent, wherein the coupling agent accounts for 0.5%-5.0% of the total mass of the mixed shielding powder and the functional core-shell powder. Further, the mixed shielding powder is one or more of the following: alumina, boron carbide, and oxides or enrichments of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium, or ytterbium, with a particle size of 200-500 mesh.

[0065] Functional core-shell powders consist of an inner core component and an outer shell component; the core component is boron carbide particles or rich in... 10 Compound B particles, with a particle size of less than 15 μm, are used for efficient absorption of thermal neutrons. The shell component is formed by coating the surface of the core component. The shell component is bismuth oxide nanoparticles or bismuth tungstate nanoparticles with a coating thickness of 100 nm-300 nm. The high atomic number and high density of the shell component endow it with excellent gamma-ray attenuation ability. It is mainly used to absorb secondary gamma rays generated by the neutron capture reaction of the core component.

[0066] For example, when boron carbide is selected as the core component and bismuth oxide as the shell component, the preparation process of functional core-shell powder is as follows:

[0067] Step S11: Boron carbide particles with a particle size D50 of 15 μm and a purity of 99.8% are uniformly dispersed in anhydrous ethanol medium at a mass concentration of 20%, and ultrasonically dispersed for 30 min to ensure sufficient deagglomeration and suspension stability of the particles.

[0068] Step S12: Under continuous stirring, slowly add a 0.2M bismuth nitrate solution and a 0.5M ammonia solution dropwise to the solution from step S11, controlling the pH of the reaction system within the range of 6.0-7.5. This pH range is conducive to the precipitation of bismuth hydroxide. Maintain the reaction temperature at 60℃-80℃ and continue the reaction for 4-6 hours. Under these conditions, bismuth hydroxide preferentially nucleates and grows heterogeneously on the surface of boron carbide particles, and then transforms into bismuth oxide nanocrystals through dehydration, thereby achieving uniform coating of bismuth oxide on the surface of boron carbide particles and obtaining a core-shell material.

[0069] After the reactions in steps S13 and S12 are completed, the coated composite powder is separated from the supernatant by centrifugation (e.g., centrifugation at 3000 rpm for 10 min). The separated precipitate is washed three times with deionized water to thoroughly remove residual ionic impurities and unreacted substances. The washed wet powder is dried in a vacuum oven at 80°C for 12 h to ensure complete removal of moisture. Finally, the dried powder is ball-milled for 1 h to effectively disperse any soft agglomerates that may form, obtaining functional core-shell powder with a particle size <25 μm and a regular morphology.

[0070] The functional core-shell powder prepared by the above steps will generate secondary gamma rays when incident neutrons are captured by the core component of the powder, such as boron carbide. These secondary gamma rays are efficiently absorbed by the shell component (e.g., bismuth oxide nanolayers) within the same particle before escaping from the functional core-shell powder. The high atomic number and high density of the shell component give it a significant attenuation capability for secondary gamma rays, achieving "in-situ" absorption and greatly reducing the probability of secondary gamma rays escaping to the outside of the coating.

[0071] Step S2: Take oil-based polyurethane resin, add modified composite shielding powder, dispersant, defoamer, coupling agent and leveling agent according to the mass ratio, stir at 1500 r / min for 50 min to 70 min, then add N,N-dimethylformamide to adjust the viscosity to 8000-15000 mPa·s, continue stirring for 15 min to 30 min, and obtain the protective coating after filtration through a sieve.

[0072] The protective coating in this step comprises the following components by weight: 10-80 parts of oil-based polyurethane resin, 5-10 parts of dispersant, 10-15 parts of defoamer, 5-10 parts of coupling agent, 5-15 parts of leveling agent, 100-300 parts of N,N-dimethylformamide, and 100-600 parts of modified composite shielding powder.

[0073] The coupling agent is one of the following: aminosilane coupling agent, epoxysilane coupling agent, mercaptosilane coupling agent, or isopropoxytitanate coupling agent. The dispersant is one of the following: phosphate ester dispersant, polyamide wax dispersant, polyurethane dispersant, or KMT-310 dispersant. The defoamer is one of the following: silicone defoamer, modified polysiloxane defoamer, or polyurethane defoamer. The leveling agent is one of the following: silicone leveling agent, acrylate leveling agent, or fluorocarbon leveling agent.

[0074] In step S2, the total mass ratio of N,N-dimethylformamide to the mixed shielding powder and the functional core-shell powder is 1:4-2.

[0075] It should be noted that the protective coating prepared in step S2 includes: a first coating mainly composed of functional core-shell powder, and a second coating entirely composed of shielding powder; in the modified composite shielding powder of the first coating, the mass ratio of functional core-shell powder to mixed shielding powder is 1:0.8-1. Furthermore, before coating the first coating, a pore-forming agent is slowly added to the first coating and stirred at low speed for 5-10 minutes. This low-speed stirring aims to ensure that the pore-forming agent particles are uniformly dispersed in the slurry, while avoiding damage to its particle structure due to high-speed shearing, thus preserving its potential for subsequent micropore formation. Further, the pore-forming agent is micron-sized ammonium bicarbonate particles with a particle size of 20μm-50μm or low-boiling-point solvent microcapsules, accounting for 0.5%-3.0% of the total mass of the functional core-shell powder.

[0076] In this step, a first coating and a second coating with different compositions are prepared, with the aim of forming multiple coating combinations with different functions in the subsequent step S3.

[0077] Step S3: Lay the pretreated fabric base flat on the conveyor device, and use a scraper to apply the protective coating to the surface of the fabric base in sequence. Adjust the coating thickness by controlling the height of the fixed scraper. The coated fabric enters the drying device through the conveyor belt to dry, and the coated fabric is obtained.

[0078] It should be noted that the pretreatment of the fabric base includes: soaking the required fabric in a 4% sodium hydroxide solution at 50°C for 30 minutes, rinsing with clean water and drying at 85°C, spraying with a mixture of coupling agent and ethanol, and curing at 70°C for 1 hour.

[0079] Specifically, the protective coating is divided into a first coating and a second coating. In one embodiment, the first coating is applied to the surface of the fabric base with a scraper and then dried to obtain a fabric with coating A1. Then, the second coating is applied according to the above operation to obtain coating B1. Coating B1 is for X-ray and gamma-ray protection and is composed of one or more of the following: alumina, boron carbide, and oxides or enrichments of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium, or ytterbium.

[0080] It is worth noting that coating A1 is mainly composed of functional core-shell powder, which solves the problem of secondary gamma-ray contamination in neutron shielding. During the preparation of coating A1, a pore-forming agent was added, and after drying, a microporous structure was formed. These micropores not only further enhance the shielding effect against gamma rays through scattering, but also help to reduce the weight of the coating and maintain the flexibility of the material.

[0081] Coating B1 is composed of high atomic number (high Z) metal oxides (such as bismuth, tungsten, gadolinium oxides, etc.), and it efficiently attenuates X-rays and gamma rays primarily through the photoelectric effect and Compton scattering. It provides basic protection against the most prevalent and prevalent X-rays in a nuclear radiation environment. Working in conjunction with coating A1, coating B1 handles primary X-rays, while coating A1 handles neutrons and secondary X-rays, together forming a complete shielding system.

[0082] Furthermore, the thickness of coating A1 is 0.4mm-0.8mm, and the thickness of coating B1 is 0.3mm-0.6mm. This coating combination of nuclear radiation protection materials is suitable for scenarios with high requirements for weight and flexibility, and where the radiation environment is mainly composed of low- to medium-energy rays, such as protective clothing for nuclear medicine interventional procedures.

[0083] In another embodiment, the second coating is made into two parts with different compositions and functions. One part of the second coating is applied to the surface of the fabric base with a scraper and then dried to obtain the fabric with coating A2. Then, the first coating and the other part of the second coating are used to make coating B2 and coating C2 respectively, finally obtaining the nuclear radiation protection coating. The schematic diagram of the coating structure is shown in the figure. Figure 3 As shown. The innermost coating, A2, is for X-ray and gamma-ray protection and is primarily composed of one or more oxides or enrichments of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium, or ytterbium. The outermost coating, C2, is primarily composed of alumina and zirconium oxide, with secondary components consisting of one or more oxides or enrichments of lanthanum, bismuth, europium, tungsten, gadolinium, zirconium, erbium, or ytterbium. Specific formulation optimization is used for external protection, focusing on wear resistance and environmental stability.

[0084] It is worth noting that coating A2 serves the same purpose as coating A1, using high-Z materials to shield X / γ rays. Coating B2 is exactly the same as coating A1, and placing it in the middle layer allows neutron rays attenuated by the outer layer (coating C2) to be effectively captured here, and the secondary γ rays generated by them to be "trapped" inside the material, where they are further absorbed by itself or by the adjacent coatings A2 and C2.

[0085] The main components of coating C2, alumina and zirconium oxide, are ceramic materials with high hardness and good wear resistance. Their primary function is to enhance the wear and scratch resistance of the coating surface and improve its environmental resistance (such as weather resistance and corrosion resistance), thereby protecting the integrity and long-term shielding effectiveness of the inner coatings A2 and B2. The secondary components of coating C2 (high-Z metal oxides) provide attenuation for X-rays, gamma rays, and neutron rays.

[0086] Furthermore, the thickness of coating A2 is 0.4mm-0.7mm, the thickness of coating B2 is 0.5mm-1.0mm, and the thickness of coating C2 is 0.1mm-0.25mm. This coating combination of nuclear radiation protection materials is suitable for scenarios with complex radiation environments and higher requirements for protection levels and durability, such as nuclear power plant maintenance and emergency response equipment.

[0087] Furthermore, the drying process for coating A or coating B made from the first coating includes three stages:

[0088] The first stage is low-temperature pre-baking. The fabric base coated with the first coating is immediately placed in an oven at 60-80℃ for pre-baking for 8-15 minutes after coating. This stage involves moderate heating to evaporate some of the solvent in the coating and to promote the initial cross-linking reaction between the modified composite shielding powder and the polyurethane resin through chemical / hydrogen bonds. During this process, the coating viscosity gradually increases, effectively fixing the position of the uniformly dispersed functional core-shell powder and pore-forming agent particles. This prevents the powder from settling or the pore-forming agent particles from agglomerating during subsequent high-temperature treatment, laying the foundation for the uniform formation of micropores.

[0089] After the first stage of pre-baking, the temperature is rapidly raised to 90-95℃ and maintained at this temperature for 5-10 minutes. Within this temperature range, if the porogen is ammonium bicarbonate, it will decompose into ammonia (NH3), carbon dioxide (CO2), and water vapor (H2O). These gaseous products expand rapidly due to the increased temperature and escape from the coating. If the porogen is a low-boiling-point solvent microcapsule, the microcapsule ruptures, and the internal low-boiling-point solvent evaporates rapidly. The escape of gas or vapor forms a large number of closed micropores with diameters ranging from 1μm to 5μm in the coating. Importantly, these micropore structures are not randomly distributed but tend to be distributed around or adjacent to the functional core-shell powder, thanks to the reasonable size ratio and spatial distribution of the porogen particles and the modified composite shielding powder. Furthermore, to ensure smooth gas escape and the formation of uniform micropores, the oven maintains a certain degree of ventilation in the second stage.

[0090] The third stage involves placing the fabric substrate, which has undergone the pore-forming agent volatilization stage, in an oven at 120-180℃ for high-temperature post-curing treatment for 10-20 minutes. This stage aims to deeply cross-link the modified composite shielding powder in the coating with the polyurethane resin, forming a highly stable three-dimensional network structure. High-temperature post-curing thoroughly stabilizes the morphology and size of the micropores, endowing the coating with final mechanical properties, radiation resistance, and chemical stability, ensuring that the microporous structure is not easily collapsed or deformed under long-term use and external stress.

[0091] The porosity of the micropores in the coating made from the first coating material was quantitatively evaluated using scanning electron microscopy (SEM) image analysis and density measurement, with a preferred porosity range of 10%-25%. The uniformity of the pore size distribution was characterized using statistical methods (such as the coefficient of variation), which should be less than 0.3 to ensure uniform distribution of micropores throughout the coating. The connectivity of the micropores was verified by a gas permeability test, with a permeability rate of less than 0.01 cm⁻¹. 3 / cm 2 The / min indicates that the micropores are relatively independent. After entering the internal space of the micropores, the propagation path of secondary gamma rays is no longer a simple straight line, but rather involves multiple scattering and reflections within the micropores and on the micropore walls. This "radiation scattering enhancement cavity" effect significantly prolongs the effective propagation path of gamma rays within the coating, increasing the probability of gamma rays interacting again with and being absorbed by the high atomic number shell components in the functional core-shell powder on or near the micropore walls. This combination of path extension and multiple interactions further enhances the absorption efficiency of secondary gamma rays.

[0092] Furthermore, these microporous structures not only play a crucial role in radiation shielding but also possess unique advantages in mechanical properties. When the coating is bent or subjected to external stress, the micropores can act as buffer zones at stress concentration points, effectively dispersing and absorbing internal stress, thereby significantly improving the overall flexibility and durability of the coating and avoiding the brittle cracking problem commonly found in high-filler inorganic powder coatings.

[0093] It is worth noting that, in the drying process of the coating obtained from the second coating, the second drying stage is omitted.

[0094] Furthermore, the multilayer functional coatings are laminated together using an adhesive with a thickness of <0.05 mm, preferably a reactive polyurethane adhesive.

[0095] Step S4: The functional film is bonded to the outer surface of the coated fabric by hot pressing, and then aligned and sealed to obtain a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0096] The functional film is one of the following: polyethylene film, polypropylene film, polyester film, nylon film, and silica film.

[0097] It should be noted that the hot pressing method in step S4 includes the following steps:

[0098] Step S41: Lay the functional film on the upper and lower molds of the hot press mold and align the positioning marks.

[0099] Step S42: Place the coated fabric in the center of the mold, ensuring that the functional film is wrinkle-free and without misalignment, and align the edge of the functional film with the mold sealing groove.

[0100] Step S43: Start the hot press equipment, and slowly lower the upper mold to apply a low pressure of 0.1-0.2MPa to the functional film and coated fabric to initially bond the two together, while expelling the interlayer air, and hold for 5-10 seconds.

[0101] Step S44: Increase the pressure to 0.3-2MPa, while the mold continues to heat, so that the functional film is fully softened and the edges of the functional film and the coated fabric are pressed together to form a sealed structure. Maintain the set pressure holding time for 30 minutes.

[0102] Step S45: After the pressure holding is completed, turn off the heating module and circulate cooling water through the mold's built-in cooling water channel. Once the temperature reaches the target, move the upper mold upwards to reset. Use a special tool to remove the sealed material from the mold to obtain a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0103] This step combines hot pressing molding with the functional film and coating to form a sealed interface, which can block the contact between water vapor, oxygen and the polyurethane cross-linked structure in the coating, avoid structural failure caused by resin hydrolysis and powder oxidation, and extend the service life of the material.

[0104] The flexible nuclear radiation protection material based on a multi-layer coating structure prepared by this invention is lightweight, soft, and has good composite shielding effect. Its application scenarios can break through the limitations of traditional rigid and heavy protective materials (such as lead plates), covering multiple fields such as personal protection, equipment protection, and special environment protection. Moreover, the preparation process is simple and controllable, easy to scale up production, and has good processability. It can cover multiple fields such as medical, nuclear industry, aerospace, and scientific research. Furthermore, with the refinement of radiation protection needs, it can be expanded to "wearable smart protection" (such as combining sensors to monitor radiation dose) in the future.

[0105] The following specific embodiments will be used to verify the specific process of preparing flexible nuclear radiation protection materials according to the present invention and the performance characteristics of the resulting materials.

[0106] All the following examples use 0.25 mm thick ultra-high molecular weight polyethylene fiber cloth as the fabric base. The fabric base is soaked in a 4% sodium hydroxide solution at 50°C for 30 min, washed with water, dried at 85°C, sprayed with a mixture of aminosilane coupling agent and ethanol, and cured at 70°C for 1 h before use.

[0107] Example 1:

[0108] The flexible nuclear radiation protection material with a multi-layer coating structure is made of the following components in parts by weight: 60 parts of oil-based polyurethane resin, 3 parts of polyamide ester dispersant, 3 parts of polyurethane defoamer, 10 parts of aminosilane coupling agent, 200 parts of N,N-dimethylformamide, 3 parts of acrylate leveling agent, and 600 parts of modified composite shielding powder.

[0109] The modified composite shielding powder is made from the following components in parts by weight:

[0110] Modified shielding powder A: 180 parts bismuth oxide, 40 parts tungsten trioxide, and 100 parts ytterbium oxide;

[0111] Modified shielding powder B: 30 parts boron carbide, 50 parts gadolinium oxide, and 90 parts functional core-shell powder;

[0112] Modified shielding powder C: 40 parts zirconium oxide and 70 parts alumina.

[0113] The core component of the functional core-shell powder is boron carbide, and the shell component is bismuth oxide nanoparticles, with a particle size D50 of 20 μm.

[0114] The preparation process of the above-mentioned flexible nuclear radiation protection material based on a multi-layer coating structure includes the following steps:

[0115] Step 1: Weigh the shielding powder according to the mass fraction, mix it, and add it to a mixed solution of 4% aminosilane coupling agent toluene. Stir at 80°C for 1.5 hours, vacuum dry at 85°C for 2.5 hours, and pass it through a 300-mesh sieve to obtain the modified composite shielding powder.

[0116] Step 2: Take oil-based polyurethane resin, add modified shielding powder A, polyamide ester dispersant, polyurethane defoamer, aminosilane coupling agent, and acrylate leveling agent. Stir at 1500 r / min for 60 min, then add N,N-dimethylformamide to adjust the viscosity to 8000 mPa·s. Continue stirring for 20 min. After filtration through a sieve, obtain protective coating A. Then, follow the above operation to change modified shielding powder A to modified shielding powders B and C to prepare protective coatings B and C.

[0117] Step 3: Lay the pretreated fabric base flat on the conveyor device, and use a scraper to apply protective coating A to the surface of the fabric base with a thickness of 0.5 mm. The coated fabric enters the drying device through the conveyor belt, is pre-dried at a low temperature of 70°C for 10 minutes, and then cured at a high temperature of 120°C for 15 minutes to obtain the fabric with coating A.

[0118] Step 4: Slowly add 2 parts of spherical ammonium bicarbonate particles with a particle size D50 of 35μm to the protective coating B according to the mass ratio, and stir at low speed for 8 minutes. Then, use a scraper to apply the protective coating B to the surface of the coating A with a thickness of 0.8mm. The coated fabric enters the drying device through a conveyor belt, and is first pre-dried at a low temperature of 70℃ for 10 minutes. The pre-dried substrate is then quickly transferred to a 92℃ oven and kept for 8 minutes with good ventilation inside the oven. Finally, it is cured at a high temperature of 120℃ for 15 minutes to obtain the fabric with coating B.

[0119] Step 5: Following the procedure in Step 3, prepare coating C on the surface of coating B with a thickness of 0.2 mm.

[0120] Step 6: Lay a 0.1mm thick polypropylene film on the upper and lower molds of the hot press mold, aligning it with the positioning marks; then place the coated fabric in the center of the mold, ensuring the film is wrinkle-free and without misalignment, and align the film edge with the mold sealing groove. Seal the edges, start the hot press equipment, raise the temperature to 120℃, and slowly lower the upper mold. First, apply a low pressure of 0.1MPa to lightly press the film and protective material to initially adhere them, while simultaneously expelling interlayer air. Maintain this pressure for 10 seconds, then increase the pressure to 2MPa while the mold continues to heat, allowing the film to fully soften and compacting the edges of the film and protective material to form a sealed structure. Maintain the set pressure holding time for 30 minutes. After the pressure holding is completed, turn off the heating module and circulate cooling water through the mold's built-in cooling water channel. Once the temperature reaches the target, move the upper mold back up and use a special tool to remove the sealed material from the mold, obtaining a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0121] Example 2:

[0122] Based on Example 1, the difference between this example and Example 1 is that in step 4, no pore-forming agent is added to the protective coating B, and it is directly scraped onto the surface of coating A.

[0123] Example 3:

[0124] Based on Example 1, the difference between this example and Example 1 is that in step 4, 5 parts of spherical ammonium bicarbonate particles with a particle size D50 of 35 μm are slowly added to the protective coating B according to the mass ratio.

[0125] Example 4:

[0126] Based on Example 1, the difference between this example and Example 1 is that the thickness of coating A is 0.8 mm, the thickness of coating B is 0.4 mm, and the thickness of coating C is 0.2 mm.

[0127] Example 5:

[0128] Based on Example 1, this embodiment differs from Example 1 in that the modified composite shielding powder is made from the following components in parts by weight:

[0129] Modified shielding powder A: 180 parts bismuth oxide, 40 parts tungsten trioxide, and 100 parts ytterbium oxide;

[0130] Modified shielding powder B: 100 parts boron carbide, 70 parts gadolinium oxide;

[0131] Modified shielding powder C: 40 parts zirconium oxide and 70 parts alumina.

[0132] The preparation process of the above-mentioned flexible nuclear radiation protection material based on a multi-layer coating structure includes the following steps:

[0133] Step 1: Weigh the shielding powder according to the mass fraction, mix it, and add it to a mixed solution of 4% aminosilane coupling agent toluene. Stir at 80°C for 1.5 hours, vacuum dry at 85°C for 2.5 hours, and pass it through a 300-mesh sieve to obtain the modified composite shielding powder.

[0134] Step 2: Take oil-based polyurethane resin, add modified shielding powder A, polyamide ester dispersant, polyurethane defoamer, aminosilane coupling agent, and acrylate leveling agent. Stir at 1500 r / min for 60 min, then add N,N-dimethylformamide to adjust the viscosity to 8000 mPa·s. Continue stirring for 20 min. After filtration through a sieve, obtain protective coating A. Then, follow the above operation to change modified shielding powder A to modified shielding powders B and C to prepare protective coatings B and C.

[0135] Step 3: Lay the pretreated fabric base flat on the conveyor device, and use a scraper to apply the protective coating A to the surface of the fabric base with a thickness of 0.5 mm. The coated fabric enters the drying device through the conveyor belt, is pre-dried at a low temperature of 70°C for 10 minutes, and then cured at a high temperature of 120°C for 15 minutes to obtain the fabric with coating A. Then, follow the above operation to make coatings B and C to obtain coatings B with a thickness of 0.8 mm and C with a thickness of 0.2 mm respectively, and finally obtain the nuclear radiation protection coating.

[0136] Step 4: Lay a 0.1mm thick polypropylene film on the upper and lower molds of the hot press mold, aligning it with the positioning marks. Then place the coated fabric in the center of the mold, ensuring the film is wrinkle-free and without misalignment, and align the film edge with the mold sealing groove. Seal the edges, start the hot press equipment, raise the temperature to 120℃, and slowly lower the upper mold. First, apply a low pressure of 0.1MPa to lightly press the film and protective material to initially adhere them, while simultaneously expelling interlayer air. Maintain this pressure for 10 seconds, then increase the pressure to 2MPa while continuously heating the mold to fully soften the film. Compact the edges of the film and protective material to form a sealed structure. Maintain the set pressure holding time for 30 minutes. After the pressure holding is completed, turn off the heating module and circulate cooling water through the mold's built-in cooling water channel. Once the temperature reaches the target, move the upper mold back up and use a special tool to remove the sealed material from the mold, obtaining a flexible nuclear radiation protection material based on a multi-layer coating structure.

[0137] Example 6:

[0138] Based on Example 1, the difference between this example and Example 1 is that in step 2, the coupling agent used is an epoxy silane coupling agent, and the metal oxides used in the modified shielding powder A are lanthanum oxide, bismuth oxide, and tungsten powder. The rest of the preparation methods are the same as in Example 1.

[0139] Example 7:

[0140] Based on Example 1, the difference between this example and Example 1 is that in step 2, the dispersant used is a phosphate ester dispersant, the defoamer used is a modified polysiloxane defoamer, the leveling agent used is an organosilicon leveling agent, and the modified shielding powder B uses 100 parts of boron carbide and 70 parts of europium oxide.

[0141] Example 8:

[0142] Based on Example 5, the difference between this example and Example 5 is that the thickness of coating A is 0.8 mm, the thickness of coating B is 1.0 mm, and the thickness of coating C is 0.2 mm.

[0143] The performance of the flexible nuclear radiation protection materials prepared in Examples 1 to 8 above will be tested below.

[0144] Prepare the instruments and adjust the energy range of the radiation source to cover multiple energy points from low energy to high energy (20keV-120keV). Place the flexible nuclear radiation protection material based on the multilayer coating structure prepared in Examples 1-8 between the radiation source and the radiation detection equipment.

[0145] At each energy point, the intensity of rays passing through the fabric is measured.

[0146] The radiation shielding rate at each energy point was calculated and recorded as (original radiation intensity - radiation intensity transmitted through the radiation shielding fabric) / original radiation intensity × 100%, and the data are shown in Table 1.

[0147] Table 1. Radiation shielding rate

[0148]

[0149] The test material is placed 241 The Am-Be thermal neutron shielding efficiency was tested under a 1.0m graphite-moderated thermal neutron radiation field. The neutron beam generated by the thermal neutron field contained more than 99% neutrons with energies below 1 eV. A collimator was fabricated using a 2mm cadmium plate, with a 30mm diameter circular aperture. The detector was a CENTRONIC SP90 spherical 3He proportional counter tube. In the thermal neutron radiation field, [the following text is incomplete and likely refers to a separate process:] ... 3 The proportional counter and collimator were placed on a trolley. By adjusting the track trolley, the effective center of the instrument was aligned with the effective center of the radiation source. The detector was 1.7 m from the source center. The sample to be tested was placed close to the neutron instrument. The high voltage was set to 1000 V, the threshold voltage to 1.75 V, the amplification factor to 30 times, and the forming time to 2 μs. The readings were recorded as the cumulative count over 500 s. The test results are shown in Table 2.

[0150] The formula for calculating the shielding rate is as follows:

[0151] Shielding rate ;

[0152] Where: n d Here, n is the count after adding the sample, and n0 is the count before adding the sample. b This is the background count.

[0153] Table 2. Test results of thermal neutron shielding efficiency

[0154]

[0155] The fabric sample is fixed flat on the fixture, ensuring the fabric surface is wrinkle-free and fits tightly against the fixture. The fabric flexibility tester is started, and data recording begins when the test probe contacts the center of the fabric sample. During the test, the bending angle and corresponding bending force of the fabric are recorded every 0.5 seconds until the fabric bends to 180° or the bending force reaches 10N (whichever comes first). The above test process is repeated 3 times to obtain 3 sets of data. The average value is taken as the test result of the fabric, as shown in Table 3.

[0156] Table 3. Mechanical performance test results

[0157]

[0158] As can be seen from Tables 1, 2, and 3 above, Example 1, as the optimal solution, exhibits the best performance in both X-ray and thermal neutron shielding efficiency, while also possessing good flexibility. This is attributed to the "core-shell-microporous" composite structure formed by its rationally configured functional core-shell powder and appropriate amount of pore-forming agent. In this structure, the core component (boron carbide) of the functional core-shell powder effectively absorbs thermal neutrons, while the shell component (bismuth oxide) achieves "in-situ" absorption of secondary gamma rays. Simultaneously, the uniform micropores formed by the pore-forming agent, through the "radiation scattering enhancement cavity" effect, extend the propagation path of gamma rays in the coating, further enhancing the absorption probability. In contrast, Example 2 lacked a pore-forming agent, resulting in insufficient absorption of secondary gamma rays and a decrease in shielding performance. Although Example 3 had abundant micropores and improved flexibility, the excessive amount of pore-forming agent caused uneven coating structure, which weakened the shielding effectiveness. Examples 5, 6, and 7 did not use functional core-shell powder. Although they contained neutron-absorbing components such as boron carbide and performed reasonably well in thermal neutron shielding, the lack of effective suppression of secondary gamma rays resulted in generally low X-ray shielding rates, especially in the energy range above 65 keV.

[0159] Example 1 achieves functional layering and stress dispersion through a reasonable coating thickness ratio, maintaining a high shielding efficiency while achieving a bending angle of 118.5° and a bending force of only 6.8 N, demonstrating excellent flexibility and wearability. However, the coating B thickness of Example 4 (0.4 mm) is too thin, resulting in insufficient absorption of secondary gamma rays generated by the neutron capture reaction, with some rays escaping the material and causing a loss of shielding efficiency. Example 8 has the same composition as Example 5, but each coating is thicker, thus achieving a better shielding efficiency, even approaching that of Example 1. However, this sacrifices material flexibility and overall coordination, indicating that multilayer coatings not only need functional complementarity but also require systematic optimization in thickness; otherwise, it is difficult to achieve the dual goals of "high shielding" and "high flexibility."

[0160] In summary, this invention achieves synergistic shielding against neutrons and gamma rays, in-situ suppression of secondary radiation, and effective maintenance of material flexibility. Through the complementary functions of multiple coating layers, it overcomes the shortcomings of traditional single-coating systems that "protect against radiation but not neutrons, and against primary radiation but not secondary radiation," achieving coverage of all radiation types. The material of this invention combines flexibility, lightweight, and high shielding efficiency, and can be processed into protective clothing, protective blankets, and other products, suitable for scenarios such as nuclear emergency response, medical radiation, and nuclear facility operation and maintenance. The manufacturing process is simple and controllable, and easy to scale up production.

[0161] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A flexible nuclear radiation protection material based on a multilayer coating structure, characterized in that, The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

2. A flexible nuclear radiation protection material based on a multilayer coating structure according to claim 1, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

3. The flexible nuclear radiation shielding material based on multilayer coating structure and the preparation method according to claim 1, characterized in that: The functional core-shell powder is composed of an internal core component and an external shell component; the core component is boron carbide particles or boron-rich 10 B compound particles, and the shell component is bismuth oxide nanoparticles or bismuth tungstate nanoparticles coated on the surface of the core component.

4. The flexible nuclear radiation shielding material based on a multilayer coating structure and the preparation method according to claim 1, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

5. A method for the production of a flexible radiation protection material based on a multilayer coating structure according to any one of claims 1 to 4, characterized in that The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

6. A method of preparing a flexible nuclear radiation shielding material based on a multilayer coating structure according to claim 5, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps. The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

7. The method for preparing a flexible nuclear radiation protection material based on a multilayer coating structure according to claim 5, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

8. A method of preparing a flexible nuclear radiation shielding material based on a multilayer coating structure according to claim 7, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

9. A method for preparing a flexible nuclear radiation protection material based on a multilayer coating structure according to claim 5, characterized in that: The application relates to a flexible nuclear radiation protection material based on a multi-layer coating structure, which comprises the following steps.

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