X-ray protective material with double-layer fiber mesh structure and preparation method thereof

Abstract

The present invention discloses an X-ray shielding material with a double-layer fiber mesh structure and a preparation method thereof, relating to the technical field of shielding material preparation. The X-ray shielding material comprises a low-light layer and a high-light layer. The low-light layer comprises a low-density fiber mesh layer and high-Z element particles adsorbed within the low-density fiber mesh layer, while the high-light layer comprises a high-density fiber mesh layer and high-Z element particles adhered within the high-density fiber mesh layer. The low-light layer is bonded below the high-light layer above. The low-density fiber mesh layer is made from raw materials including fiber 1 and fiber 2, with fiber 2 adsorbing high-Z element particles through surface intermolecular interactions in an aqueous environment. The high-density fiber mesh layer is made from bicomponent fiber, including core fiber and sheath fiber, with the sheath fiber being used to adhere to the high-Z element particles after melting. The present invention implements a preparation method for using a fiber mesh to load high-Z element particles, fully mixing the high-Z particles and improving X-ray shielding effectiveness.

Description

Technical Field

[0001] The present invention belongs to the technical field of X-ray protective materials, and in particular relates to an X-ray protective material with a double-layer fiber mesh structure and a preparation method thereof. Background Art

[0002] X-rays, as high-energy electromagnetic radiation with powerful penetration, have played an important role in a variety of fields, including medical diagnosis, scientific research, and industrial flaw detection. However, prolonged or excessive exposure to X-ray radiation can pose a series of harmful effects on the human body, including cell damage, gene mutations, and even health risks such as leukemia and thyroid disease. The potential threat of X-rays is particularly prominent for sensitive groups such as pregnant women and children. As the application of X-rays continues to expand, their use cases are becoming increasingly complex. Therefore, to meet the demand for X-ray protection in various environments, the development of efficient and lightweight X-ray shielding materials is crucial. X-ray protection is not only of great significance for protecting human health, but also ensures the accuracy and safety of medical diagnoses, providing strong support for scientific research and industrial development.

[0003] Currently, the core shielding material of most X-ray shielding materials on the market is lead-containing rubber. However, lead is a well-established carcinogen and is also quite heavy. For example, the preparation method described in patent publication number CN113929356A proposes the addition of various chemical substances, such as vulcanizing agents and adhesives. However, this method involves a complex refining process, high costs, and high energy consumption. Furthermore, even if the required protection is achieved, the resulting X-ray shielding material is still relatively heavy. Therefore, current research focuses on making shielding materials lead-free, lightweight, and highly efficient.

[0004] Currently, research into the preparation of X-ray shielding materials mostly involves blending non-lead, high-Z element particles with polymers. Improving the uniformity of the dispersion of these high-Z element particles within the material is a proven method for enhancing the material's photon absorption performance. However, the method described in patent application CN115910407A, which uses silane coupling agents to modify BI2O3 and EU2O3, is time-consuming, resulting in low efficiency in actual production. Furthermore, the modification requires a high environmental profile, making it difficult to ensure uniform particle dispersion. This increases operational complexity and difficulty, hindering large-scale application.

[0005] The aforementioned methods for preparing high-Z element particle shielding materials suffer from challenges such as difficulty in achieving uniform dispersion, low dispersion efficiency, easily contaminated chemical raw materials, and heavy material weight. This present invention leverages the structural characteristics of fiber meshes and utilizes fibers with varying surface properties to provide an efficient and convenient method for dispersing and loading particles, enabling the production of highly effective and lightweight X-ray shielding materials. Summary of the Invention

[0006] The purpose of the present invention is to provide an X-ray protective material with a double-layer fiber mesh structure and a preparation method thereof, so as to solve the problems of the preparation method of X-ray protective materials in the prior art proposed in the above background technology, such as difficulty in uniform dispersion, low dispersion efficiency, easy contamination of chemical raw materials, heavy weight of the finished material, etc.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions:

[0008] A first aspect of the present invention provides an X-ray shielding material having a double-layer fiber mesh structure, comprising a low-light layer and a high-light layer. The low-light layer comprises a low-density fiber mesh layer and high-Z element particles adsorbed within the low-density fiber mesh layer, and the high-light layer comprises a high-density fiber mesh layer and high-Z element particles adhered within the high-density fiber mesh layer. The low-light layer is bonded to the high-light layer above.

[0009] The low-density fiber mesh layer is prepared from raw materials including fiber 1 and fiber 2. The modulus of fiber 1 is in the range of 80 to 600 GPa. Fiber 2 is a natural fiber with a rich hydroxyl group on the fiber surface. Fiber 2 is used to adsorb high-Z element particles.

[0010] The raw material for preparing the high-density fiber mesh layer is bicomponent fiber, which includes core fiber and sheath fiber. The melting point of the sheath fiber is lower than that of the core fiber. The sheath fiber is used to adhere to the high-Z element particles after melting.

[0011] Preferably, the high-Z element particles include one or more elements with an atomic number Z of 56 to 83, wherein the element is in the form of oxide, simple substance or inorganic salt.

[0012] In this invention, the near-light layer utilizes the enhanced intermolecular forces on the surface of bamboo fibers in an aqueous environment to achieve efficient adsorption and dispersion of high-Z element particles. This layer is constructed as a low-density fiber mesh. The far-light layer utilizes the different melting points of the inner and outer materials of the bicomponent fiber to uniformly adhere the high-Z element particles under controlled hot pressing temperatures. Furthermore, due to the higher melting point of the inner layer, the fiber mesh structure is maintained, ultimately forming a high-density fiber mesh layer. This invention implements a preparation method for high-Z element particles loaded on a fiber mesh, fully mixing the high-Z particles and improving X-ray protection.

[0013] A second aspect of the present invention provides a method for preparing an X-ray shielding material with a double-layer fiber mesh structure, comprising the following steps:

[0014] S1, preparation of the near light layer;

[0015] Adding fiber 1, fiber 2, and deionized water to a cutting blender, cutting and stirring at room temperature to preliminarily mix fiber 1 and fiber 2, with the preliminary mixing stirring time being 3 to 30 seconds; then adding high-Z element particles to the cutting blender, cutting and stirring for 10 to 100 seconds to obtain a mixture of fiber 1 / fiber 2 / high-Z element particles / deionized water; treating the mixture to completely remove the deionized water, and drying to obtain a low-density mixture of fiber 1 / fiber 2 / high-Z element particles, i.e., a near-light layer;

[0016] S2, preparation of the far light layer;

[0017] The bicomponent fibers are opened and then combed into a web by a carding machine to obtain a fiber web, which is then processed by a needle-carding machine to obtain a needle-punched cloth. High-Z element particles are evenly sprayed on the needle-punched cloth using a granulator, and then needle-punched to insert the high-Z element particles between the fibers. The needle-punched cloth containing the high-Z element particles is placed in a mold and then hot-pressed for 4 to 100 minutes at a temperature of 160 to 220° C. After hot pressing, a high-density needle-punched fiber material, i.e., a high-beam layer, is obtained.

[0018] S3. Preparation of X-ray protective material with double-layer fiber mesh structure;

[0019] The high beam layer is spread flat on the bottom of the mold, and the low beam layer is completely attached to the high beam layer. Water-based polyurethane is poured into the mold to immerse the low beam layer in the water-based polyurethane. The stacked low beam layer and high beam layer are then taken out and dried to obtain an X-ray protective material with a double-layer fiber mesh structure.

[0020] Preferably, the fiber 1 is carbon fiber or hemp fiber.

[0021] Furthermore, the fiber 1 added by the cutting stirrer in S1 has a fiber length ranging from 0.1 to 10.0 cm, preferably from 0.5 to 2.0 cm. If the fiber 1 is too long, it is not conducive to cutting and stirring, while if it is too short, the shear force provided during rotation is reduced, which is not conducive to particle dispersion.

[0022] Preferably, the fibers 2 are wood pulp fibers.

[0023] Furthermore, the fiber 2 is made of cotton fiber, bamboo fiber or hemp fiber.

[0024] Preferably, the bicomponent fiber uses a core / skin layer of PET / PAN, PET / PP, or PET / PA. PET (polyethylene terephthalate) has a melting point higher than the hot pressing temperature of 160-220°C; PAN, PP, and PA have melting points lower than the hot pressing temperature of 160-220°C, and melt after hot pressing to adhere to the high-Z element particles.

[0025] Preferably, the high-Z element particles are bismuth oxide particles.

[0026] Furthermore, the diameter of the high-Z element particles in S1 ranges from 30 to 500 nanometers.

[0027] Furthermore, the diameter of the high-Z element particles in S2 ranges from 0.5 to 100 microns, preferably from 5 to 40 microns.

[0028] Preferably, the weight of the fiber 2 in S1 is 10% to 200% of the weight of the fiber 1, and the weight of the deionized water is 20 to 80 times the total weight of the fiber 1 and the fiber 2.

[0029] Preferably, the mixture is treated in S1 to completely remove the deionized water, specifically by filtering the mixture, and then squeezing and drying the mixture or directly drying the mixture to completely remove the deionized water.

[0030] Furthermore, the fiber 1 / fiber 2 / high-Z element particles / deionized water mixture is poured into a filter dish to filter out the flowing deionized water; a pressure cap is placed on the mixture, and the weight of the pressure cap is adjusted according to the diameter of the filter dish so that the pressure range of the pressure cap on the mixture is 20 to 300N, and then the mixture is allowed to stand and dry to completely remove the deionized water; or the deionized water is removed by drying, and the mixture together with the filter dish is placed in an oven for drying and forming, and the drying temperature is appropriate not to affect the properties of the fibers used. After complete drying, a fluffy and porous fiber 1 / fiber 2 / high-Z element particle mixture is obtained.

[0031] Preferably, the needle-punched fabric in S2 is processed as follows: first, the bicomponent fibers are opened to obtain loose single fibers or small fiber bundles; the fibers are combed into a web by a carding machine, and the obtained fiber web has a thickness ranging from 100 to 600 g / m 2 , preferably 210~300g / m 2 The fiber web is passed through a needle carding machine, and the needle carding machine needle punching frequency range is set to 30 to 500 punctures / minute, preferably 100 to 200 punctures / minute.

[0032] Preferably, the hot pressing in S2 is specifically as follows: placing the needle-punched cloth mixed with high-Z element particles into a mold with a thickness of 0.5 to 4 mm, followed by hot pressing (hot pressing pressure range 1.5 to 4 MPa), hot pressing time 4 to 100 min, and hot pressing temperature 160 to 220°C.

[0033] Preferably, the low beam layer in S3 is immersed in waterborne polyurethane, specifically: the solid content of the waterborne polyurethane is 5% to 40% to ensure sufficient fluidity; the solid content of the waterborne polyurethane is 15% to 20% of the weight of the added high-Z element particles.

[0034] Preferably, after drying in S3, an X-ray protective material with a double-layer fiber mesh structure is obtained, specifically: it is dried by standing still or in an oven. If drying in an oven is adopted, the drying temperature cannot be higher than 60°C, and the drying time can be adjusted with the temperature, and finally an X-ray protective material with a double-layer fiber mesh structure is obtained.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The X-ray protection material with a double-layer fiber mesh structure in the present invention is prepared by mixing-stacking-adsorption. The material is rich in pores and has a low density, allowing more photons to penetrate into the material. The far-light layer uses a high-density needle-punched cloth material that has been heat-pressed to form a tightly arranged "micro-chamber" structure. This double-layer density gradient design material can reduce scattering on the one hand: the low-density design of the near-light layer helps to reduce the scattering of photons on the surface of the material, thereby reducing the impact of scattered radiation on the environment; the high density of the far-light layer helps to capture those photons that penetrate the near-light layer, further reducing scattering. On the other hand, it can improve the absorption efficiency of the material: the porous structure of the near-light layer allows photons to penetrate deep into the material and collide with high-Z particles multiple times, thereby improving the absorption efficiency; the compact structure of the far-light layer ensures that the remaining photons are effectively absorbed. This design significantly enhances the scattering and absorption effect of photons between fiber layers, thereby improving the overall protection ability of the material against radiation. In addition, this type of X-ray material with a fiber mesh structure can achieve a certain air permeability while maintaining X-ray protection.

[0037] (2) The present invention designs a near-light layer, and the high-modulus fiber has good shape stability. During the stacking process, a three-dimensional network structure is constructed, which effectively physically separates the bismuth oxide particles and provides more paths for X-ray scattering and absorption. The physical properties of the high-strength fiber generate shear force and impact force during the stirring process, improve the agglomeration of nanoparticles, increase the specific surface area, and thus increase the probability of the photoelectric effect, thereby improving the X-ray protection ability of the material. In addition, wood pulp fibers have high surface energy and polarity due to the hydroxyl groups they contain, which makes them more likely to adsorb polar particles, such as nano-bismuth oxide particles. This material structure allows the bismuth oxide particles to be evenly and firmly dispersed between the fibers, forming a compact photon absorption space, reducing photon escape, and improving the efficiency of the photoelectric effect. Photons collide multiple times between the fibers, extending the free path, reducing the energy to complete absorption, and achieving an X-ray protection effect. This design significantly improves the photon scattering probability and transmission distance, so that the finished product has excellent X-ray protection performance.

[0038] (3) The present invention designs a high-beam layer, attaching particles to a fiber mesh. This creates a certain amount of porosity in the material, allowing it to maintain a certain degree of air permeability while ensuring X-ray protection. However, most commercially available X-ray protection materials are made by directly mixing polymers with high-Z particles, resulting in essentially zero air permeability.

[0039] (4) The X-ray protective material with a double-layer fiber mesh structure in the present invention is light in material and has good protective effect while ensuring the protective effect. Compared with the traditional lead rubber material, the lightweight and efficient X-ray protective material prepared by the present invention can achieve an effect of 0.35mmpb when the mass is 25.6g (9cm diameter disc) under a tube voltage of 80KV, which exceeds the national standard (0.25mmpb). In addition, the lead rubber material with a 0.35mmpb effect purchased on the market (cut into 9cm diameter discs) has a mass of 32.17g. Compared with the materials used in the market, the weight of the X-ray protective material prepared by this method is reduced by 20%. In addition, when the addition amount of high-Z particles of this material is 12, 16, 20, 24, and 28g, its protective effect at 80KV is significantly improved, and it can be used to prepare lightweight and efficient X-ray protective materials.

[0040] (5) The present invention designs an extremely simple and highly efficient method for reducing the agglomeration of nanoparticles and promoting the uniform dispersion of nanoparticles in polymers. Only a very small amount of auxiliary fibers need to be added to achieve the dispersion of agglomerated particles. This method can be applied not only to the field of X-ray protection, but also to other functional fields that require uniform dispersion of nanoparticles, and has extremely strong potential application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a method for preparing an X-ray shielding material with a double-layer fiber mesh structure according to the present invention;

[0042] Figure 2 A schematic diagram of an X-ray source irradiating an X-ray shielding material in the present invention;

[0043] Figure 3 This is an electron microscope image of the near-light layer of the X-ray shielding material of the present invention;

[0044] Figure 4 This is an electron microscope image of a fiber of the X-ray shielding material of the present invention that has adsorbed high-Z element particles;

[0045] Figure 5 This is an electron microscope image of the far-field layer of the X-ray shielding material of the present invention;

[0046] Figure 6 This is a graph showing the air permeability test results of the X-ray shielding material prepared in Example 1 of the present invention;

[0047] Figure 7 This is a comparison chart of the effects of the X-ray shielding material prepared in Example 1 of the present invention and materials on the market;

[0048] Figure 8 The figure compares the protective effects of protective materials with and without fiber mesh structures. DETAILED DESCRIPTION

[0049] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0050] Example 1:

[0051] like Figure 1 As shown, the preparation method of the X-ray shielding material with a double-layer fiber mesh structure is as follows:

[0052] S1. Weigh 0.6g of carbon fiber and chop it to 1.5cm. Then, mix it with 0.2g of bamboo fiber and 50g of deionized water in a cutting blender. Start the cutting blender and stir at room temperature for 5 seconds for preliminary mixing. Next, weigh 12g of bismuth oxide particles and add them to the cutting blender containing the preliminary mixture of carbon fiber and bamboo fiber. Stir again for 30 seconds to obtain a mixture of carbon fiber, bamboo fiber, and bismuth oxide. Pour the mixture into a 9cm diameter filter dish, filter out the excess deionized water, and then dry it in a 40°C oven for 24 hours to form a fluffy, porous mixture.

[0053] S2. Open the bicomponent fiber (PET / PP) to obtain loose single fibers or fiber bundles of a certain length. Weigh 50.4g of the opened fibers and spread them evenly on the conveyor belt of the carding machine for combing. Comb twice to obtain a fiber web of 30cm×80cm. Take the combed fiber web and spread it flat on the conveyor belt of the needle loom, and then perform needle punching with a frequency of 100-200 needle punches / min. After obtaining a uniform pre-needled cloth, cut the needle-punched cloth into discs with a diameter of 9cm and evenly spray 12g of bismuth oxide particles on it using a granulator. In order to evenly disperse the particles in the needle-punched cloth, perform another needle punching to insert the particles between the fibers, and then perform hot pressing (hot pressing pressure 2Mpa), hot pressing time 10min, and hot pressing temperature at 160°C. After hot pressing, a second layer of needle-punched fiber material with a higher density is obtained.

[0054] S3. The second layer (needle-punched material) was evenly laid on the bottom of a 9 cm diameter polytetrafluoroethylene mold. The first layer (a fluffy, porous high-strength fiber / bamboo fiber / bismuth oxide mixture) was then laid on top. Aqueous polyurethane was poured in, immersing the high-strength fiber / bamboo fiber / bismuth oxide mixture in the aqueous polyurethane. 25 g of aqueous polyurethane (15% solids content) was poured in. The mixture was then dried in an oven at 45°C for 24 h to yield a double-layer composite material containing 24 g of BiO.

[0055] The performance test of the double-layer composite material is as follows:

[0056] In this embodiment, the double-layer composite material is a double-layer superimposed structure of a low beam layer and a high beam layer. Figure 2 As shown, the double-layer composite material prepared by irradiating an X-ray source is irradiated with the X-ray source. The layer close to the X-ray source is the near-light layer, and the layer far from the X-ray source is the far-light layer. The electron microscope image of the near-light layer of the sample of Example 1 is shown in FIG. Figure 3 、 Figure 4 As shown in Figure 2, nano-bismuth oxide forms a covering layer on the surface of bamboo fiber. Figure 5 As shown, it can be seen that micron-sized bismuth oxide is evenly dispersed inside the fiber mesh. Due to the different melting points of the two-component fibers, the skin layer adheres to the bismuth oxide particles after melting, but the material still retains the fiber mesh structure.

[0057] In this embodiment, the air permeability of the prepared X-ray shielding composite material was tested according to GB 5453-1997 "Determination of Air Permeability of Textile Fabrics". According to the standard, the test pressure was set to 200Pa, and the air permeability effect was measured as follows: Figure 6 However, the lead rubber material purchased on the market has basically no breathable effect.

[0058] In this embodiment, the sample obtained according to the preparation method has a mass of 25.6 g and a lead equivalent effect of 0.35 mm pb when the amount of bismuth oxide added is 24 g. Compared with the lead rubber with the same shielding effect on the market (cut into 9 cm diameter discs), the mass is 32.17 g. Under the same effect, the weight reduction effect can be improved by 20%. The comparative effect is as follows: Figure 7 shown.

[0059] Example 2:

[0060] The preparation method of the X-ray shielding material with a double-layer fiber mesh structure is as follows:

[0061] S1. Weigh 0.6g of carbon fiber and cut it into 1.5cm pieces. Then mix it with 0.2g of cotton fiber and 50g of deionized water in a cutting blender. Start the cutting blender and stir for 40s at room temperature for preliminary mixing. Then weigh 12g of bismuth oxide particles and add them to the cutting blender containing the preliminary mixture of carbon fiber and cotton fiber. Stir again for 30s to obtain a mixture of carbon fiber, cotton fiber and bismuth oxide. Pour the mixture into a 9cm diameter filter dish, filter out the excess deionized water, and then dry it in a 40℃ oven for 24h to form a fluffy, porous mixture.

[0062] S2. Open the bicomponent fiber (PET / PP) to obtain loose single fibers or fiber bundles of a certain length. Weigh 50.4g of the opened fibers and spread them evenly on the conveyor belt of the carding machine for combing. Comb twice to obtain a fiber web of 30cm×80cm. Take the combed fiber web and spread it flat on the conveyor belt of the needle loom, and then perform needle punching with a frequency of 100-200 needle punches / min. After obtaining a uniform pre-needled cloth, cut the needle-punched cloth into discs with a diameter of 9cm and evenly spray 12g of bismuth oxide particles on it using a granulator. In order to evenly disperse the particles in the needle-punched cloth, perform another needle punching to insert the particles between the fibers, and then perform hot pressing (hot pressing pressure 2Mpa), hot pressing time 10min, and hot pressing temperature at 160°C. After hot pressing, a second layer of needle-punched fiber material with a higher density is obtained.

[0063] S3. Lay the second layer (needle-punched material) evenly on the bottom of a 9 cm diameter polytetrafluoroethylene mold. Then, lay the first layer (a fluffy, porous mixture of high-strength fiber, cotton fiber, and bismuth oxide) on top. Pour in 25 g of water-based polyurethane (15% solids content) to immerse the high-strength fiber, cotton fiber, and bismuth oxide mixture in the water-based polyurethane. Dry in an oven at 45°C for 24 hours to obtain a sample of the near-light layer obtained by adsorption on the cotton fiber.

[0064] In Example 2, cotton fibers were used to successfully adsorb high-Z element particles in the near-light layer, which once again demonstrated the adsorption effect of natural fibers on nanoparticles in an aqueous environment.

[0065] Example 3:

[0066] The preparation method of the X-ray shielding material with a double-layer fiber mesh structure is as follows:

[0067] S1. Weigh 0.6g of carbon fiber and chop it to 1.5cm. Then, mix it with 0.2g of bamboo fiber and 50g of deionized water in a cutting blender. Start the cutting blender and stir at room temperature for 40 seconds for preliminary mixing. Next, weigh 12g of bismuth oxide particles and add them to the cutting blender containing the preliminary mixture of carbon fiber and bamboo fiber. Stir again for 30 seconds to obtain a mixture of carbon fiber, bamboo fiber, and bismuth oxide. Pour the mixture into a 9cm diameter filter dish, filter out the excess deionized water, and then dry it in a 40°C oven for 24 hours to form a fluffy, porous mixture.

[0068] S2. Open the bicomponent fiber (PET / PAN) to obtain loose single fibers or fiber bundles of a certain length. Weigh 50.4g of the opened fibers and spread them evenly on the conveyor belt of the carding machine for combing. Comb twice to obtain a fiber web of 30cm×80cm. Take the combed fiber web and spread it flat on the conveyor belt of the needle loom, and then perform needle punching with a frequency of 100-200 needle punches / min. After obtaining a uniform pre-needled cloth, cut the needle-punched cloth into discs with a diameter of 9cm and evenly spray 12g of bismuth oxide particles on it using a granulator. In order to evenly disperse the particles in the needle-punched cloth, perform another needle punching to needle the particles into the spaces between the fibers, and then perform hot pressing (hot pressing pressure 2Mpa), the hot pressing time is 10min, and the hot pressing temperature is 160°C. After hot pressing, a second layer of needle-punched fiber material with a higher density is obtained.

[0069] S3. The second layer (needle-punched material) was evenly laid on the bottom of a 9 cm diameter polytetrafluoroethylene mold. The first layer (a fluffy, porous mixture of high-strength fiber, bamboo fiber, and bismuth oxide) was then laid on top. Aqueous polyurethane was poured in, immersing the high-strength fiber, bamboo fiber, and bismuth oxide mixture in the aqueous polyurethane. 25 g of aqueous polyurethane (15% solids content) was poured. The mixture was dried in an oven at 45°C for 24 hours to obtain a sample obtained by adhesion of the bicomponent fiber (PET / PAN) to the high-light layer.

[0070] Example 3 uses a bicomponent fiber (PET / PAN), in which the skin layer is polyacrylonitrile with a lower melting point and the core layer is polyethylene terephthalate with a higher melting point. After hot pressing, the fiber material completely adheres to the 12g bismuth oxide particles added to the high-beam layer.

[0071] Example 4:

[0072] The preparation method of the X-ray shielding material with a double-layer fiber mesh structure is as follows:

[0073] S1. Weigh 1.2g of carbon fiber and chop it to 1.5cm. Then, mix it with 0.2g of bamboo fiber and 50g of deionized water in a cutting blender. Start the cutting blender and stir at room temperature for 40 seconds for preliminary mixing. Next, weigh 12g of bismuth oxide particles and add them to the cutting blender containing the preliminary mixture of carbon fiber and bamboo fiber. Stir again for 30 seconds to obtain a mixture of carbon fiber, bamboo fiber, and bismuth oxide. Pour the mixture into a 9cm diameter filter dish, filter out the excess deionized water, and then dry it in a 40°C oven for 24 hours to form a fluffy, porous mixture.

[0074] S2. Open the bicomponent fiber (PET / PAN) to obtain loose single fibers or fiber bundles of a certain length. Weigh 50.4g of the opened fibers and spread them evenly on the conveyor belt of the carding machine for combing. Comb twice to obtain a fiber web of 30cm×80cm. Take the combed fiber web and spread it flat on the conveyor belt of the needle loom, and then perform needle punching with a frequency of 100-200 needle punches / min. After obtaining a uniform pre-needled cloth, cut the needle-punched cloth into discs with a diameter of 9cm and evenly spray 12g of bismuth oxide particles on it using a granulator. In order to evenly disperse the particles in the needle-punched cloth, perform another needle punching to needle the particles into the spaces between the fibers, and then perform hot pressing (hot pressing pressure 2Mpa), the hot pressing time is 10min, and the hot pressing temperature is 160°C. After hot pressing, a second layer of needle-punched fiber material with a higher density is obtained.

[0075] S3. The second layer (needle-punched material) was evenly laid on the bottom of a 9cm diameter polytetrafluoroethylene mold. The first layer (a fluffy, porous mixture of high-strength fiber, bamboo fiber, and bismuth oxide) was then laid on top of the first layer. Aqueous polyurethane was poured in, and the high-strength fiber, bamboo fiber, and bismuth oxide mixture was immersed in the aqueous polyurethane. 25g of aqueous polyurethane (15% solids content) was poured. The mixture was dried in an oven at 45°C for 24 hours to obtain a sample obtained by adsorption of the bamboo fiber to the near-light layer.

[0076] The sample obtained by the method of Example 4 was prepared. Compared with Example 1, Example 4 only changed the amount of carbon fiber added. However, the lead equivalent of Example 4 was 0.37 mmpb, which was an improvement over the lead equivalent effect of 0.35 mmpb of the sample in Example 1, further proving that carbon fiber helps to improve the X-ray protection performance of the material.

[0077] Comparative Example 1:

[0078] S1. Weigh different masses of nano-bismuth oxide particles (12g, 16g, 20g, 24g, 28g) and place them in a beaker. According to the weighed bismuth oxide particles, accurately weigh 1 / 2 of the mass of the water-based polyurethane (solid content of 38%). Pour the same into the beaker containing the bismuth oxide particles. Place the beaker containing bismuth oxide and water-based polyurethane on a magnetic stirrer. Stir for 12 minutes at room temperature using a magnetic stirrer at 1000 revolutions per minute.

[0079] S2. After stirring, quickly pour the mixture into a 9 cm diameter polytetrafluoroethylene mold. Manually shake to evenly distribute the mixture, then dry it in a 40°C oven for 24 hours. Remove the mixture from the mold to obtain a control sample.

[0080] The protective material was prepared by using the preparation method in Example 1, and 12g, 16g, 20g, 24g, and 28g of bismuth oxide particles were added respectively. The comparative sample was prepared using the same bismuth oxide particles and waterborne polyurethane as in Example 1, and 12g, 16g, 20g, 24g, and 28g of bismuth oxide particles were added. The protective effect was compared with that of Example 1. Figure 8 It can be seen that the X-ray protection effect of the protective material with a fiber mesh structure is significantly improved at different addition amounts.

[0081] The above description is only used to help understand the method and core essence of the present invention, but the scope of protection of the present invention is not limited thereto. For those skilled in the art, equivalent replacements or modifications based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention should be included in the scope of protection of the present invention. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An X-ray protective material with a double-layer fiber mesh structure, characterized in that: It includes a low-beam layer and a high-beam layer, wherein the low-beam layer includes a low-density fiber mesh layer and high-Z element particles adsorbed in the low-density fiber mesh layer, and the high-beam layer includes a high-density fiber mesh layer and high-Z element particles adhered to the high-density fiber mesh layer; the low-beam layer is attached to the high-beam layer above. The low-density fiber mesh layer is prepared from fibers 1 and 2. The modulus of fiber 1 is in the range of 80 to 600 GPa. Fiber 2 is a natural fiber rich in hydroxyl groups on the fiber surface. Fiber 2 utilizes surface intermolecular interactions in an aqueous environment to adsorb high-Z element particles. The raw material for preparing the high-density fiber mesh layer is bicomponent fiber, which includes core fiber and sheath fiber. The melting point of the sheath fiber is lower than that of the core fiber. The sheath fiber is used to adhere to the high-Z element particles after melting.

2. The X-ray shielding material with a double-layer fiber mesh structure according to claim 1, characterized in that: The high-Z element particles include one or more elements with an atomic number Z of 56 to 83; wherein the element is in the form of oxide, simple substance or inorganic salt.

3. A method for preparing the X-ray shielding material with a double-layer fiber mesh structure as claimed in claim 1 or 2, characterized in that: The steps include: S1, preparation of the near light layer; Add fiber 1, fiber 2 and deionized water into a cutting mixer, cut and stir at room temperature to preliminarily mix fiber 1 and fiber 2. The stirring time for the preliminary mixing is 3 to 30 seconds. Then, high-Z element particles are added to the cutting and stirring device, and the mixture is cut and stirred for 10 to 100 seconds to obtain a mixture of fiber 1 / fiber 2 / high-Z element particles / deionized water. The mixture is treated to completely remove the deionized water, and dried to obtain a low-density mixture of fiber 1 / fiber 2 / high-Z element particles, i.e., the near-light layer. S2, preparation of the far light layer; The bicomponent fibers are opened and then combed into a web by a carding machine to obtain a fiber web, which is then processed by a needle-carding machine to obtain a needle-punched cloth. High-Z element particles are evenly sprayed on the needle-punched cloth using a granulator, and then needle-punched to insert the high-Z element particles between the fibers. The needle-punched cloth containing the high-Z element particles is placed in a mold and then hot-pressed for 4 to 100 minutes at a temperature of 160 to 220° C. After hot pressing, a high-density needle-punched fiber material, i.e., a high-beam layer, is obtained. S3. Preparation of X-ray protective material with double-layer fiber mesh structure; The high beam layer is spread flat on the bottom of the mold, and the low beam layer is completely attached to the high beam layer. Water-based polyurethane is poured into the mold to immerse the low beam layer in the water-based polyurethane. The stacked low beam layer and high beam layer are then taken out and dried to obtain an X-ray protective material with a double-layer fiber mesh structure.

4. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 3, characterized in that: The fiber 1 is made of carbon fiber or hemp fiber.

5. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 3, characterized in that: The fiber 2 is wood pulp fiber.

6. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 5, characterized in that: The fiber 2 is made of cotton fiber, bamboo fiber or hemp fiber.

7. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 3, characterized in that: The core layer / skin layer of the bicomponent fiber is PET / PAN, PET / PP or PET / PA.

8. The method for preparing an X-ray shielding material with a double-layer fiber mesh structure according to claim 3, characterized in that: The diameter of the high-Z element particles in S1 ranges from 30 to 500 nanometers; the diameter of the high-Z element particles in S2 ranges from 0.5 to 100 micrometers.

9. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 8, characterized in that: The high-Z element particles are bismuth oxide particles.

10. The method for preparing a double-layer fiber mesh structure X-ray shielding material according to claim 3, characterized in that: The weight of the fiber 2 in S1 is 10% to 200% of the weight of the fiber 1, and the weight of the deionized water is 20 to 80 times the total weight of the fiber 1 and the fiber 2.

Images