Light, lead-free and breathable nuclear protective clothing and preparation method thereof

Abstract

The invention relates to the technical field of nuclear protective clothing, in particular to light, lead-free and breathable nuclear protective clothing and a preparation method thereof. The preparation method comprises the following steps: blending BWWT composite shielding particles and polypropylene to prepare master batches, modifying, carrying out melt spinning to form nascent fibers, carrying out ultrasonic cavitation and electrostatic field synergistic treatment on the nascent fibers, and carrying out hot stretching and shaping to obtain composite fibers; carding and lapping the composite fibers, and performing needling treatment and supercritical carbon dioxide treatment to obtain a 3D composite fiber needled fabric; meanwhile, coating the modified polyimide film with a bismuth solution twice, and performing hot pressing to obtain the light lead-free protective material. Finally, the two are connected through a sewing process to form the nuclear protection suit.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear protective clothing, and in particular relates to a lightweight, lead-free, breathable nuclear protective clothing and a preparation method thereof. Background Art

[0002] In the field of nuclear radiation protection, traditional nuclear protective clothing generally uses lead-containing materials as shielding layers, but this has significant drawbacks: first, the high density of lead makes protective clothing heavy, uncomfortable to wear, and affects operational flexibility; second, lead is a toxic heavy metal, posing environmental pollution and human health risks during production and use. With the development of radiation protection technology, lead-free, lightweight, breathable and comfortable protective clothing have become urgent industry demands.

[0003] While existing lead-free nuclear protection materials attempt to utilize bismuth- and tungsten-based shielding particles as alternatives, these particles (such as bismuth oxide and tungsten oxide) tend to aggregate within the polymer matrix, leading to uneven dispersion and the formation of weak shielding areas. This significantly reduces attenuation efficiency, particularly in high-energy radiation environments. Furthermore, traditional fabric structures struggle to balance shielding performance with breathability. The dense shielding layer impedes air and water vapor flow, leading to heat and moisture accumulation in sweat-prone areas (such as the underarms, neck, and back), severely impacting comfort and safety during prolonged work.

[0004] Therefore, developing a method for preparing nuclear protective clothing that has high-efficiency shielding, lightweight lead-free and breathable properties has become the key to solving existing problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a lightweight, lead-free, breathable nuclear protective suit and a preparation method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a lightweight, lead-free, breathable nuclear protective clothing, comprising the following steps: Step 1: BWWT composite shielding particles are blended with polypropylene to obtain a masterbatch, which is then modified and melt-spun to form composite fibers; the composite fibers are combed and directionally stacked into a composite fiber web, which is then needle-punched and treated with supercritical carbon dioxide to produce a 3D composite fiber needle-punched fabric; wherein the modified masterbatch is melt-spun to obtain nascent fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment; Step 2: coating the modified polyimide film with a bismuth solution twice and hot pressing the film to produce a lightweight lead-free protective material; Step 3: Connect the 3D composite fiber needle-punched fabric and the lightweight lead-free protective material through a sewing process to produce a nuclear protective suit; Among them, the synergistic treatment of ultrasonic cavitation and electrostatic field is carried out in an inert environment at an ultrasonic frequency of 38 to 42 kHz and an electrostatic field strength of -30 to -20 kV for 3 to 7 minutes, and the acupuncture treatment adopts 120 punctures / cm 2 Up to 150 thorns / cm 2 The needle density is between 1.6 and 2.0 mm.

[0007] Furthermore, the preparation method of the 3D composite fiber needle-punched fabric includes: S1: Melt-blending and extruding BWWT composite shielding particles with polypropylene to obtain a masterbatch; S2: Surface modification of the masterbatch is followed by melt spinning to form nascent fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment, and then heat-stretched to obtain composite fibers; S3: Cutting the composite fibers to a fixed length and combing them into a single-layer fiber web, and directionally stacking the single-layer fiber webs to obtain a composite fiber web; S4: performing air curtain guidance and needle punching treatment on the composite fiber web to obtain a needle punched fabric intermediate; S5: performing gradient hot pressing and pressure-maintaining cooling on the preheated needle-punched fabric intermediate to obtain a compressed and shaped fabric; S6: The compressed and shaped fabric is subjected to supercritical carbon dioxide treatment and rapid pressure relief, and then subjected to hot roller rolling and cooling and shaping to obtain a 3D composite fiber needle-punched fabric; Among them, gradient hot pressing includes the following three consecutive pressure stages: In the first stage, a pressure of 0.4–0.6 MPa is applied for 8–12 s; In the second stage, a pressure of 2.5–3.0 MPa was applied for 17–23 s; In the third stage, a pressure of 5.0-6.0 MPa is applied for 25-35 s.

[0008] Furthermore, the preparation method of the masterbatch includes: 55-65 wt% bismuth oxide, 10-20 wt% tungsten oxide, 10-20 wt% tungsten carbide and 5-15 wt% tantalum oxide were dry-mixed at 750-850 rpm for 10-15 min to form BWWT composite shielding particles; 30-40 wt% polypropylene and 60-70 wt% BWWT composite shielding particles are melt-blended at a temperature of 165-190 °C and a rotation speed of 110-130 rpm for 3-5 min. After filtering to remove impurities with a diameter greater than 50 μm, the melt is extruded into strips through a 1-3 mm die hole, passed into a 22-28 °C circulating water cooling tank for solidification, and finally cut into cylindrical masterbatches with a length of 1-6 mm and a diameter of 1-3 mm.

[0009] Furthermore, the masterbatch modification method includes: adding the masterbatch into an anhydrous ethanol solution of KH560 silane coupling agent with a pH of 4.0-5.0 and a concentration of 1-3 wt%, and refluxing for 80-100 minutes at 65-75°C and a stirring speed of 180-220 rpm; after the reaction, filtering, rinsing with anhydrous ethanol 3-5 times, and vacuum drying at 75-85°C for 3-5 hours to obtain a modified masterbatch.

[0010] Furthermore, the heat stretching and shaping method includes introducing the as-spun fiber after the coordinated treatment of ultrasonic cavitation and electrostatic field into a 130-140°C environment, regulating the orientation crystallization with a stretching ratio of 1.9-2.3, and shaping it with a cooling roller at 22-28°C to obtain a composite fiber.

[0011] Furthermore, the method of cutting to length includes cutting the composite fibers into fiber bundles of fixed length of 5.0 to 8.0 cm.

[0012] Furthermore, the unit area mass of the single-layer fiber web is 0.045 to 0.055 g / cm 2 .

[0013] Furthermore, the preparation method of the lightweight lead-free protective material comprises the following steps: M1: modifying the polyimide film to obtain a modified polyimide film; M2: A bismuth solution is coated on a modified polyimide film to form a wet film, which is then heat-pressed to obtain a composite film intermediate with a bismuth coating. M3: The bismuth solution is coated again on the surface of the composite membrane intermediate to form a wet film. After hot pressing, a composite membrane with a thickened bismuth coating is obtained; M4: The composite film is subjected to calendering treatment and then cooled and shaped to obtain a lightweight lead-free protective material; The hot pressing treatment includes preheating at 265-275 °C and 0.05-0.2 MPa for 19-21 min, then heating to 290-300 °C and 24-26 MPa for 14-16 min.

[0014] Furthermore, the suturing process comprises the following steps: T1: Cut the 3D composite fiber needle-punched fabric and lightweight lead-free protective material into pieces, cut the pieces and spray the functional adhesive layer; T2: sew the processed pieces together; T3: Apply hot melt tape to the seams and pulse heat press to bond; T4: Melt seal the seam.

[0015] Another technical solution provided by the present invention is: a lightweight, lead-free, breathable nuclear protective clothing, prepared by the above-mentioned preparation method, including a sweat-prone part and other parts, wherein the sweat-prone part is a 3D composite fiber needle-punched fabric, and the other parts are lightweight lead-free protective materials.

[0016] The present invention solves the defects existing in the background technology and has the following beneficial effects: The present invention uses a synergistic treatment of specific ultrasonic frequencies and electrostatic field strengths in an inert environment on spun fibers. When the transient cavitation bubbles generated by ultrasonic cavitation collapse, a strong impact force is released to break up the agglomerates in the BWWT composite shielding particles. At the same time, the electrostatic field makes the surface of the bismuth oxide particles modified by KH560 positively charged, and a directional electrostatic repulsion force is generated between adjacent particles to resist the reagglomeration caused by van der Waals forces, thereby achieving uniform dispersion of the BWWT composite shielding particles in the polypropylene matrix, reducing local shielding blind spots, and enhancing the interface bonding between the particles and the matrix. Compared with the prior art, in which highly filled particles are prone to agglomeration, resulting in local shielding blind spots, and the interface bonding between the particles and the matrix is ​​weak, the preparation method provided by the present invention improves the radiation shielding uniformity of nuclear protective clothing, while enhancing the elongation at break and avoiding the problem of easy breakage due to local stress concentration.

[0017] The present invention adopts 120-150 thorns / cm 2 The composite fiber mesh is needle-punched at a density of 1.6-2.0 mm and a penetration depth of 1.6-2.0 mm, so that the needles form moderate entanglements in the fiber mesh. This ensures sufficient cohesion between the fibers to maintain structural stability without over-compressing the pores between the fibers, retaining the uniformity and connectivity of the pores, maintaining the good pore structure of the composite fiber mesh, ensuring the smooth passage of air and water vapor, and ensuring the structural stability of the needle-punched fabric intermediate. Compared with the air permeability and structural stability problems caused by pore collapse or loose structure in the prior art, the present invention improves the air permeability and moisture permeability while ensuring the structural stability of the 3D composite fiber needle-punched fabric, thereby enhancing the wearing comfort of nuclear protective clothing.

[0018] The present invention realizes uniform dispersion of particles based on the coordinated processing of ultrasonic cavitation and electrostatic field, and optimizes fiber entanglement and pore structure based on acupuncture treatment; wherein, uniform dispersion of particles reduces local stress concentration, enhances the interface bonding between fibers and particles, and is beneficial to the uniform entanglement of fibers and the stable formation of pore structure during the acupuncture process, so that the protective clothing exhibits more stable and efficient shielding performance in a wide energy spectrum, while having excellent air permeability, moisture permeability and mechanical toughness, achieving a unified improvement in protective effectiveness and wearing comfort, and overcoming the performance limitations of the prior art caused by particle agglomeration and structural unevenness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts. Figure 1 It is a flow chart of a method for preparing a lightweight, lead-free, breathable nuclear protective suit; Figure 2 This is a flow chart of a method for preparing a 3D composite fiber needle-punched fabric; Figure 3 It is a flow chart of a preparation method for preparing a lightweight lead-free protective material; Figure 4 It is a flow chart of a suturing process. DETAILED DESCRIPTION

[0020] The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below. Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art. Among them, the following materials were purchased from Sinopharm: bismuth oxide, tungsten oxide, tungsten carbide, and tantalum oxide (all with a purity greater than 99%), KH560 silane coupling agent, and KH550 silane coupling agent; polyimide film was purchased from Alfa (ThermoFisher); tungsten powder (99.9%, 200nm) and bismuth powder (99.99%, 200 mesh) were purchased from MacLean Reagent.

[0021] like Figure 1 As shown, a method for preparing a lightweight, lead-free, breathable nuclear protective suit comprises the following steps: Step 1: BWWT composite shielding particles are blended with polypropylene to obtain a masterbatch, which is then modified and melt-spun to form composite fibers; the composite fibers are combed and directionally stacked into a composite fiber web, which is then needle-punched and treated with supercritical carbon dioxide to produce a 3D composite fiber needle-punched fabric; wherein the modified masterbatch is melt-spun to obtain nascent fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment; Step 2: coating the modified polyimide film with a bismuth solution twice and hot pressing the film to produce a lightweight lead-free protective material; Step 3: Connect the 3D composite fiber needle-punched fabric and the lightweight lead-free protective material through a stitching process to produce nuclear protective clothing.

[0022] like Figure 2 As shown, a method for preparing a 3D composite fiber needle-punched fabric comprises the following steps: S1: Melt-blending and extruding BWWT composite shielding particles with polypropylene to obtain a masterbatch; S2: Surface modification of the masterbatch is followed by melt spinning to form nascent fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment, and then heat-stretched to obtain composite fibers; S3: Cutting the composite fibers to a fixed length and combing them into a single-layer fiber web, and directionally stacking the single-layer fiber webs to obtain a composite fiber web; S4: performing air curtain guidance and needle punching treatment on the composite fiber web to obtain a needle punched fabric intermediate; S5: performing gradient hot pressing and pressure-maintaining cooling on the preheated needle-punched fabric intermediate to obtain a compressed and shaped fabric; S6: The compressed and shaped fabric is treated with supercritical carbon dioxide and the pressure is quickly released, and a 3D composite fiber needle-punched fabric is obtained after hot roller rolling and cooling and shaping.

[0023] Below, each step will be described in detail.

[0024] In step S1, the BWWT composite shielding particles are first mixed, and then the BWWT composite shielding particles and polypropylene are melt-blended and extruded in proportion, and finally cooled and pelletized to obtain a masterbatch.

[0025] Specifically, pre-dried bismuth oxide, tungsten oxide, tungsten carbide, and tantalum oxide were dry-mixed at a mass ratio of 55-65 wt% bismuth oxide, 10-20 wt% tungsten oxide, 10-20 wt% tungsten carbide, and 5-15 wt% tantalum oxide at 750-850 rpm for 10-15 minutes to form BWWT composite shielding particles. Simultaneously, polypropylene was dried.

[0026] Next, the pre-dried polypropylene and BWWT composite shielding particles are melt-blended at a mass ratio of 30-40 wt% polypropylene and 60-70 wt% BWWT composite shielding particles at a temperature of 165-190 °C and a rotation speed of 110-130 rpm for 3-5 min; after filtering to remove impurities with a diameter greater than 50 μm, the strip melt is extruded through a 1-3 mm die hole, passed into a 22-28 °C circulating water cooling tank for solidification, and finally cut into cylindrical masterbatches with a length of 1-6 mm and a diameter of 1-3 mm.

[0027] During the melt blending process, after the polypropylene is melted, the molecular chains are oriented under shear action, and the agglomerates of BWWT composite shielding particles are mechanically broken; bismuth oxide undergoes plastic deformation and fills the gaps between hard particles such as tungsten oxide and tungsten carbide, and tungsten carbide penetrates the gaps between the polypropylene molecular chains through its sharp edges to form mechanical anchoring points.

[0028] In step S2, the masterbatch is first surface-modified to obtain a modified masterbatch, the modified masterbatch is melt-spun to form a spun fiber, the spun fiber is then subjected to a synergistic treatment of ultrasonic cavitation and electrostatic field, and finally heat-stretched to obtain a composite fiber.

[0029] Specifically, the surface modification method involves adding the dried masterbatch to an anhydrous ethanol solution of KH560 silane coupling agent with a pH of 4.0-5.0 and a concentration of 1-3 wt% (liquid-to-solid ratio of 4-6:1). The mixture is refluxed at 65-75°C and stirred at 180-220 rpm for 80-100 minutes. After the reaction, the mixture is filtered, rinsed 3-5 times with anhydrous ethanol, and vacuum-dried at 75-85°C for 3-5 hours to obtain the modified masterbatch.

[0030] During the surface modification process, only bismuth oxide reacted effectively with KH560 due to its rich hydroxyl groups on the surface to achieve significant modification, tungsten oxide reacted slightly, and tungsten carbide, tantalum oxide and polypropylene matrix did not participate in the reaction.

[0031] The melt spinning method involves feeding KH560 covalently grafted bismuth oxide-surface-modified BWWT / PP masterbatch into a spinning machine and extruding the melt at a barrel temperature of 170-190°C and a screw speed of 45-55 rpm. The melt is extruded through a spinneret with a diameter of 0.18-0.22 mm at a linear speed of 0.7-0.9 m / s and then solidified in a water-cooled tank at 22-28°C, producing spun fibers with a diameter of 0.25-0.35 mm.

[0032] The method for synergistic ultrasonic cavitation and electrostatic field treatment involves continuously introducing spun fibers into a synergistic ultrasonic cavitation and electrostatic field treatment tank at a rate of 7.0-8.0 m / min. The tank is filled with deoxygenated anhydrous ethanol (liquid level 14-16 cm). Ultrasonic transducers are mounted on the bottom and sides of the treatment tank. Parallel plate electrodes (upper electrode negative, lower electrode positive) are positioned on the top and bottom of the tank to generate an electrostatic field perpendicular to the direction of travel of the spun fibers. High-purity nitrogen gas is continuously introduced into the tank at 1.5-2.5 L / min to maintain an inert atmosphere with an oxygen concentration not exceeding 500 ppm. Treatment is performed for 3-7 minutes at an ultrasonic frequency of 38-42 kHz and an electrostatic field strength of -20 to -30 kV.

[0033] The high-frequency sound waves generated by the ultrasonic transducer form periodic pressure fluctuations in anhydrous ethanol, prompting the generation of a large number of transient cavitation bubbles inside the liquid. The strong impact force released when the bubbles collapse directly acts on the BWWT composite shielding particle agglomerates inside the primary fibers, among which the more brittle tungsten oxide is preferentially broken and deagglomerated; at the same time, the electrostatic field formed by the upper and lower plates makes the surface of the KH560-modified bismuth oxide particles positively charged, generating a directional electrostatic repulsion between adjacent particles, effectively resisting the reagglomeration caused by van der Waals forces and achieving uniform dispersion of the particles in the fiber matrix.

[0034] The heat stretching shaping method includes introducing the fiber treated by ultrasonic cavitation and electrostatic field into a 130-140°C environment, regulating the orientation crystallization at a stretching ratio of 1.9-2.3, and shaping it with a cooling roller at 22-28°C to obtain a composite fiber.

[0035] In step S3, the composite fibers are cut to a fixed length and combed into a single-layer fiber web, which is then oriented and stacked to form a composite fiber web.

[0036] Specifically, the cut-to-length method includes cutting the composite fibers into 5-8 cm fixed-length fiber bundles.

[0037] The method for carding a single-layer fiber web comprises delivering a fixed-length fiber bundle to a carding device, and carding the fixed-length fiber bundle to a fiber weight per unit area of ​​0.04-0.06 g / cm2 at a cylinder speed of 750-850 rpm and a doffer speed of 22-28 rpm. 2 During the combing process, static electricity generated by fiber friction causes the negatively charged tungsten oxide particles and the positively charged bismuth oxide particles to spontaneously distribute in a gradient.

[0038] The method of directional stacking includes grabbing 5 to 10 layers of single-layer fiber webs and laying them down in sequence while maintaining a fluffy state to obtain a composite fiber web.

[0039] In step S4, the composite fiber web is subjected to air curtain guidance and needle punching treatment to form a needle-punched fabric intermediate.

[0040] Specifically, the air curtain guidance method includes introducing the composite fiber web into the air curtain guidance area at a rate of 0.7-0.9 m / min, and treating it with a laminar air curtain (temperature 22-28 ° C) with a vertical downward flow rate of 0.8-1.2 m / s for 0.4-0.6 min to keep the fibers fluffy and evenly distributed.

[0041] The needling method includes introducing the fiber web after air curtain control into the needling device, using pressure feedback needles to perform needling along a preset path, with a needling density of 120-150 needles / cm 2 The needle-punch system uses a penetration depth of 1.6-2.0 mm and a frequency of 550-650 needles / min. After every 8-12 cm of travel, the fabric surface temperature is monitored in real time. When the local temperature exceeds 50°C, a compressed air cooling system is triggered (for a duration of 2.5-3.5 seconds), ultimately forming a needle-punched fabric intermediate with a thickness of 3-5 mm.

[0042] During the acupuncture process, the pressure feedback needle maintains a stable penetration depth by adjusting the driving parameters to ensure uniform fiber entanglement; tantalum oxide has a high hardness and easily generates local heat due to friction with the needle, while tungsten carbide enhances fiber connectivity through its angular structure and promotes the formation of a three-dimensional structure.

[0043] In step S5, the needle-punched fabric intermediate is preheated and then subjected to gradient hot pressing, and then cooled under pressure to obtain a compressed and shaped fabric.

[0044] Specifically, the preheating method includes sending the needle-punched fabric intermediate into a preheating channel (temperature 75-85° C.) at a rate of 0.45-0.55 m / min and treating for 2-5 minutes.

[0045] The preheated needle-punched fabric intermediate is transferred to a hot press (upper and lower pressing plate temperatures 95-105°C) for three-stage gradient hot pressing from low to high: In the first stage, a pressure of 0.4-0.6 MPa is applied for 8-12 seconds. The pressure in this stage is relatively low and is used to compact the surface fibers of the needle-punched fabric intermediate. In the second stage, a pressure of 2.5-3.0 MPa is applied for 17-23 seconds. During this stage, the pressure is significantly increased and effectively transmitted to the middle layer of the fabric, causing the main fiber network of the needle-punched fabric intermediate to further slip, entangle, and densify. In the third stage, a pressure of 5.0-6.0 MPa is applied for 25-35 s; the high pressure in this stage ultimately ensures that the core layer of the needle-punched fabric intermediate is fully compacted and relaxes the fiber stress in a thermal environment.

[0046] By controlling the rate and duration of gradual pressure increase, the fibers in the thickness direction of the entire needle-punched fabric intermediate are guided to be compressed and shaped in an orderly manner from the outside to the inside, avoiding problems such as over-compaction of the surface, insufficient compaction of the interior or fiber damage caused by a single high pressure, thereby achieving uniform compression.

[0047] The pressure-maintaining cooling method includes maintaining pressure until the fabric temperature drops to 37-43°C, opening the pressing plate, and outputting the compressed and shaped fabric through the roller at a rate of 0.9-1.1 m / min to fix the compression deformation.

[0048] In step S5, the compressed and shaped fabric is subjected to supercritical carbon dioxide treatment, followed by rapid pressure relief and hot roller rolling, and finally cooled and shaped to obtain a 3D composite fiber needle-punched fabric.

[0049] Specifically, the supercritical carbon dioxide treatment method includes placing the compressed and shaped fabric in a supercritical carbon dioxide treatment kettle, sealing it, heating it to above 31°C, increasing the pressure to above 7.4 MPa, and maintaining it for 25-40 minutes.

[0050] The method of rapid pressure relief includes reducing the pressure to normal pressure within 0.5-1 s at a rate of 8-10 MPa / s.

[0051] The hot roller rolling method includes introducing the treated compressed and shaped fabric into a double-roll hot rolling machine, and rolling it three times at a speed of 0.75-0.85 m / min under the conditions of a roller surface temperature of 95-105°C and a linear pressure of 0.4-0.6 MPa.

[0052] The cooling and shaping method comprises the steps of shaping the rolled fabric through a cooling air duct at 23-27° C. to obtain a 3D composite fiber needle-punched fabric.

[0053] Above the critical temperature and pressure, supercritical carbon dioxide forms a fluid state with both gas diffusivity and liquid solubility. Its molecules can penetrate the free volume of the amorphous region of polypropylene and form an enrichment layer at the interface between the BWWT composite shielding particles and polypropylene due to the difference in interfacial energy. When the pressure drops suddenly, the dissolved carbon dioxide rapidly precipitates from the polypropylene matrix due to supersaturation, triggering micropore nucleation in the amorphous region. The corners of the tungsten carbide become preferential nucleation sites due to stress concentration.

[0054] like Figure 3 As shown, a method for preparing a lightweight lead-free protective material comprises the following steps: M1: modifying the polyimide film to obtain a modified polyimide film; M2: A bismuth solution is coated on a modified polyimide film to form a wet film, which is then heat-pressed to obtain a composite film intermediate with a bismuth coating. M3: The bismuth solution is coated again on the surface of the composite membrane intermediate to form a wet film. After hot pressing, a composite membrane with a thickened bismuth coating is obtained; M4: The composite film is calendered and cooled and shaped to obtain a lightweight lead-free protective material.

[0055] Specifically, the modification treatment method in step M2 includes immersing the polyimide film in a 0.9-1.1 wt% KH550 silane coupling agent ethanol solution, treating it at 45-55°C for 4.5-5.5 minutes, and then drying it with hot air at 75-85°C for 9-11 minutes to form a modified layer to enhance the bonding strength between the surface and the subsequent coating, thereby obtaining a modified polyimide film.

[0056] In step M2, the preparation method of the bismuth solution includes mixing bismuth oxide (65-75 wt%), tantalum oxide (20-30 wt%), and tungsten carbide (0-10 wt%), and mixing them with anhydrous ethanol in a mass ratio of 1:2.5-3.5 by ultrasonic dispersion to obtain a bismuth solution.

[0057] The coating method comprises coating the bismuth solution on the surface of the modified polyimide film at a rate of 230-270 mm / min to form a wet film of 180-220 μm.

[0058] The hot pressing treatment method includes sending the coated modified polyimide film into a hot press, preheating it at 265-275°C and 0.05-0.2 MPa for 19-21 minutes, then heating it to 290-300°C and 24-26 MPa and pressing it for 14-16 minutes to allow the bismuth-based shielding particles to be tightly stacked and firmly bonded to the modified polyimide film substrate; finally, maintaining the pressure and cooling it to a temperature below 80°C to obtain a composite film intermediate with a bismuth coating.

[0059] In step M3, the secondary coating method includes re-coating the bismuth coating surface of the composite film intermediate with a bismuth solution of the same specification at a rate of 230-270 mm / min to form a wet film of 180-220 μm; the hot pressing method is the same as step M2 to obtain a composite film with a thickened bismuth coating.

[0060] In step M4, the calendering method includes feeding the composite film into the calender at a rate of 32-38 m / min, setting the upper roller temperature to 95-105°C, the middle roller temperature to 80-90°C, the lower roller temperature to 70-80°C, the roller spacing to 0.9-1.1 mm, and the line pressure to 450-550 N / cm.

[0061] The cooling and shaping method includes introducing the calendered composite film into a cooling roller group at 22-28°C for shaping, thereby obtaining a lightweight lead-free protective material.

[0062] like Figure 4 As shown, a suturing process includes the following steps.

[0063] T1: Cut the 3D composite fiber needle-punched fabric and lightweight lead-free protective material into pieces, cut the pieces and spray the functional adhesive layer; T2: sew the processed pieces together; T3: Apply hot melt tape to the seams and pulse heat press to bond; T4: Melt seal the seam.

[0064] Specifically, the step-cutting method in step T1 involves cutting the seamed edges (5-10 mm width) of the 3D composite fiber needle-punched fabric and the lightweight lead-free protective material pieces, adjusting the cutting angle to create a matching inclined contact surface at the seamed contact area. The cutting slope of the seamed edges of the 3D composite fiber needle-punched fabric is 10-20°, while the cutting slope of the seamed edges of the lightweight lead-free protective material is 20-30° (the slopes are different to accommodate the thickness characteristics of the materials). This ensures a tight fit during seaming, avoiding steps or gaps.

[0065] The method of spraying the functional adhesive layer includes spraying 60-70 wt% tungsten powder epoxy resin glue on the surface of the suture contact area after cutting, curing it at 75-85 ° C for 3-10 minutes, forming a 0.1-0.5 mm thick functional adhesive layer to enhance the sealing and bonding strength of the joint.

[0066] In step T2, the suturing connection method includes using nitinol suture to perform double-thread lock suturing along the suture contact area at a rate of 800 stitches / min with a stitch length of 1.9-2.1 mm to ensure that the two layers of material are firmly connected.

[0067] In step T3, the pulse hot pressing method includes pre-laminating a hot melt tape containing 78-82 wt% bismuth powder to the joint, and pulse hot pressing it at 118-122°C and 0.45-0.55 MPa for 4.5-5.5 seconds. The edge of the tape covers 2.8-3.2 mm on both sides of the suture line to strengthen the joint bonding strength.

[0068] In step T4, a thermoplastic polyurethane melt at 185-195°C (die lip gap 0.33-0.37 mm) is extruded along the seam. Simultaneously, hot air at 98-102°C (wind speed 2.8-3.2 m / s) assists in spreading the melt. The sealing layer covers 0.9-1.1 mm on each side of the hot melt tape. Finally, the seam is shaped by a cooling roller at 14-16°C, completing the seaming process.

[0069] A lightweight, lead-free, breathable nuclear protective suit, produced by the aforementioned method, includes areas prone to sweating and other areas. The areas prone to sweating are made of 3D composite fiber needle-punched fabric, while the other areas are made of lightweight, lead-free protective material. It should be noted that areas prone to sweating refer to areas of the human body with high metabolism and dense sweat glands, such as the armpits, neck, back, palms, and groin. These areas are prone to heat and sweat accumulation during activity, so the use of 3D composite fiber needle-punched fabric with improved breathability ensures wearer comfort.

[0070] Example 1:

[0071] Step 1: Preparation of 3D composite fiber needle-punched fabric: S1: 60 wt% bismuth oxide, 15 wt% tungsten oxide, 15 wt% tungsten carbide, and 10 wt% tantalum oxide were dry-blended at 800 rpm for 15 min to form BWWT composite shielding particles. 35 wt% polypropylene and 65 wt% BWWT composite shielding particles were melt-blended at 180°C and 120 rpm for 5 min. After filtering to remove impurities larger than 50 μm in diameter, the melt was extruded into strips through a 2 mm die, solidified in a 25°C circulating water cooling tank, and cut into cylindrical masterbatches with a length of 3 mm and a diameter of 2 mm.

[0072] S2: The masterbatch was added to a 2 wt% KH560 silane coupling agent anhydrous ethanol solution (liquid-to-solid mass ratio of 5:1) at pH 4.5. The mixture was refluxed at 70°C and 200 rpm for 90 min. After filtration, the mixture was rinsed three times with anhydrous ethanol and dried under vacuum at 80°C for 4 h to obtain the modified masterbatch. The modified masterbatch was then fed into a spinning machine and melt-extruded at a barrel temperature of 180°C and a screw speed of 50 rpm. The melt was extruded through a 0.2 mm spinneret at a linear speed of 0.8 m / s and solidified in a 25°C water-cooled tank to obtain spun fibers with a diameter of 0.3 mm.

[0073] The as-spun fibers were introduced into a treatment tank containing deoxygenated anhydrous ethanol (liquid level 15 cm) at a rate of 7.5 m / min. Ultrasonic transducers were installed at the bottom and side walls of the tank, with upper and lower plates forming an electrostatic field (directed perpendicular to the fiber's travel direction). Simultaneously, 2 L / min of high-purity nitrogen (oxygen concentration <500 ppm) was introduced. The treatment was conducted at an ultrasonic frequency of 40 kHz and an electrostatic field strength of -20 kV for 3 minutes. The fibers were then heated at 135°C and stretched at a draw ratio of 2.1. The composite fibers were then shaped by cooling rollers at 25°C to obtain the final fibers.

[0074] S3: The composite fiber was cut into 6 cm fixed-length fiber bundles; the fixed-length fiber bundles were sent to the carding equipment and combed into a unit area mass of 0.05 g / cm at a cylinder speed of 800 rpm and a doffer speed of 25 rpm. 2 single-layer fiber web; grab 7 layers of single-layer fiber webs and stack them in a directional manner, keeping them in a fluffy state, to obtain a composite fiber web.

[0075] S4: The composite fiber web was introduced into the air curtain control area at a rate of 0.8 m / min and treated with a vertical laminar air curtain at 25°C and a flow rate of 1.0 m / s for 0.5 min; then introduced into the needle punching device at a rate of 120 needles / cm 2 The needle punching was performed with a density of 1.6 mm, a penetration depth of 1.6 mm, and a frequency of 600 punches / min. After each 10 cm stroke, if the local temperature exceeded 50 °C, the compressed air cooling spray was triggered for 3 seconds, and finally a needle-punched fabric intermediate with a thickness of 4 mm was formed.

[0076] S5: The needle-punched fabric intermediate was sent into an 80°C preheating channel at a rate of 0.5 m / min for 3 min, then transferred to a 100°C hot press and pressurized in three stages: 0.5 MPa for 10 s, 2.7 MPa for 20 s, and 5.5 MPa for the remaining 30 s; the pressure was maintained until the fabric temperature dropped to 40°C, and the fabric was discharged at a rate of 1.0 m / min to obtain a compressed and shaped fabric.

[0077] S6: The compressed and shaped fabric was placed in a supercritical carbon dioxide treatment kettle, heated to 31.1°C and pressurized to 7.39 MPa, maintained for 30 min; the pressure was released to normal pressure within 1 s at a rate of 8 MPa / s, and the fabric was introduced into a double-roll hot rolling machine (100°C roller surface temperature, 0.5 MPa linear pressure), rolled three times at a rate of 0.8 m / min, and shaped in a 25°C cooling duct to obtain a 3D composite fiber needle-punched fabric.

[0078] Step 2: Lightweight lead-free protective material: M1: The polyimide film was immersed in a 1.0 wt% KH550 silane coupling agent ethanol solution, treated at 50 °C for 5 minutes, and then dried with hot air at 80 °C for 10 minutes to obtain a modified polyimide film.

[0079] M2: A bismuth solution with a viscosity of 5000 mPa·s was prepared by mixing 70 wt% bismuth oxide, 25 wt% tantalum oxide, and 5 wt% tungsten carbide in anhydrous ethanol at a mass ratio of 1:3 and dispersing it ultrasonically at 40 kHz for 20 minutes. The bismuth solution was then coated onto the surface of a modified polyimide film at a rate of 250 mm / min to form a 200 μm wet film. The film was then preheated at 270°C and 0.1 MPa for 20 minutes in a hot press, then pressed at 295°C and 25 MPa for 15 minutes. The film was then cooled to 70°C while maintaining pressure to obtain a bismuth-coated composite film intermediate. M3: A bismuth solution (200 μm wet film) was applied a second time at the same rate to the bismuth coating surface of the composite membrane intermediate, and the above hot pressing treatment was repeated to obtain a composite membrane with a thickened bismuth coating.

[0080] M4: The composite film was fed into the calender at a rate of 35 m / min, with the upper roll at 100°C, the middle roll at 85°C, the lower roll at 75°C, the roll gap at 1.0 mm, and the line pressure at 500 N / cm. After calendering, the composite film was introduced into a 25°C cooling roll group for shaping to obtain a lightweight lead-free protective material.

[0081] Step 3: Suture process: T1: 3D composite fiber needle-punched fabric and lightweight lead-free protective material were cut into pieces, and the seamed edges of the two were cut: the 3D composite fiber needle-punched fabric edge was cut at a slope of 15°, and the lightweight lead-free protective material edge was cut at a slope of 25° to form a matching inclined contact surface. Epoxy resin adhesive containing 65 wt% tungsten powder was sprayed on the contact surface and cured at 80°C for 5 minutes to form a 0.3 mm thick functional adhesive layer. T2: Double-lock suture along the contact area was performed using nitinol suture at a rate of 800 stitches / min; T3: Apply a hot-melt adhesive tape containing 80 wt% bismuth powder to the joint and pulse hot press at 120°C and 0.5 MPa for 5 seconds. T4: 190 ℃ thermoplastic polyurethane melt is extruded along the seam, and simultaneously spread with 100 ℃, 3.0 m / s hot air. It is shaped by a 15 ℃ cooling roller and stitched to obtain a lightweight, lead-free, breathable nuclear protective clothing.

[0082] Example 2:

[0083] The difference between this embodiment and embodiment 1 is that the electrostatic field strength in S2 is -25 kV; the needle density in S4 is 135 needles / cm 2 , the penetration depth is 1.8 mm.

[0084] Example 3:

[0085] The difference between this embodiment and embodiment 1 is that the electrostatic field strength in S2 is -30 kV; the needle density in S4 is 150 needles / cm 2 , the penetration depth is 2.0 mm.

[0086] Example 4:

[0087] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 5 min, the electrostatic field strength is -20 kV, and the needle density in S4 is 150 needles / cm 2 , the penetration depth is 1.6 mm.

[0088] Example 5:

[0089] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 5 min, the electrostatic field strength is -25 kV, and the needle density in S4 is 135 needles / cm 2 , the penetration depth is 1.8 mm.

[0090] Example 6:

[0091] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 5 min, the electrostatic field strength is -30 kV, and the needle density in S4 is 120 needles / cm 2 , the penetration depth is 2.0 mm.

[0092] Example 7:

[0093] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 7 min, the electrostatic field strength is -20 kV, and the needle density in S4 is 135 needles / cm 2 , the penetration depth is 2.0 mm.

[0094] Example 8:

[0095] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 7 min, the electrostatic field strength is -25 kV, and the needle density in S4 is 150 needles / cm 2 , the penetration depth is 1.6 mm.

[0096] Example 9:

[0097] The difference between this embodiment and embodiment 1 is that the treatment time in S2 is 7 min, the electrostatic field strength is -30 kV, and the needle density in S4 is 120 needles / cm 2 , the penetration depth is 1.8 mm.

[0098] Comparative Example 1: This comparative example is different from Example 5 in that the ultrasonic cavitation and electrostatic field coordinated treatment is not performed in S2.

[0099] Experimental Example 1: The nuclear protective clothing prepared in Examples 1-9 and Comparative Example 1 was cut into 10 cm×10 cm samples, 5 parallel samples were taken from each group, and the following tests were performed.

[0100] 1. X-ray attenuation efficiency test: An X-ray diffractometer was used to fix the sample on the test platform. The X-ray energy range was 30-100 keV. The transmission intensity of the sample at 8 characteristic energy points (30 keV, 40 keV, 50 keV, 60 keV, 70 keV, 80 keV, 90 keV and 100 keV) and the incident intensity when there was no sample were recorded. The attenuation efficiency was calculated using the formula (1-transmission intensity / incident intensity) × 100%. Each sample was tested 3 times at each energy point, and the average value was taken. The minimum and maximum attenuation efficiency of each sample (including sweating parts and other parts, where the sweating parts accounted for 30% of the area and the other parts accounted for 70%) in the entire range of 30-100 keV were recorded as the attenuation efficiency range of the part. The sweating parts and other parts were selected at the range of 30-100 keV. The minimum and maximum attenuation efficiency values ​​measured within the keV energy range are multiplied by the area ratio and weighted averaged to obtain the average attenuation efficiency of the overall protective clothing.

[0101] 2. Air Permeability Test: Use a digital air permeability tester. Clamp the sample in the test chamber and set the test pressure difference to 200 Pa. The instrument automatically records the volume of air passing through the sample within 1 minute and calculates the air permeability per unit time. Each sample is tested twice, with an interval of 10 seconds to achieve equilibrium.

[0102] 3. Water Vapor Transmission Rate (WVTR) Test: Using the constant temperature and humidity weighing method, place a moisture permeable cup (6 cm diameter) filled with 20 g of anhydrous calcium chloride (particle size 2-5 mm). Seal the sample, covering the cup opening (test area 28.26 cm²), and place it in an environmental chamber at 38°C and 90% relative humidity. After 24 hours, remove the cup and weigh it. The WVTR is calculated using the formula (total mass after moisture absorption - initial total mass) / test area. Maintain a wind speed of 0.5 m / s in the environmental chamber during the test.

[0103] 4. Elongation at break test: Using a universal materials testing machine, cut the sample into 5 cm × 1 cm strips and clamp them between upper and lower clamps (clamping distance 3 cm). Set the tensile rate to 50 mm / min and record the elongation at break. Calculate the elongation at break using the formula (elongation at break / initial clamping distance) × 100%. Test each sample three times, and take the average after removing outliers.

[0104] All test data are rounded to one decimal place, and the mean and standard deviation of each group of samples are calculated to ensure data accuracy and repeatability. The results are shown in the following table: Table 1 Experimental results comparison table 1

[0105] Table 2 Experimental results comparison table 2

[0106] The experimental results show that in Comparative Example 1, which did not undergo the combined ultrasonic cavitation and electrostatic field treatment, the attenuation efficiency in sweat-prone areas ranged from 73.0% to 92.5%, significantly lower than that of all the examples. This is because the BWWT composite shielding particles (particularly tungsten oxide and bismuth oxide) easily agglomerated within the untreated nascent fibers, resulting in uneven distribution within the polypropylene matrix and the formation of localized weak shielding areas. In the high-energy X-ray region (approximately 100 keV), the enhanced radiation penetration makes the gaps between the agglomerates ineffective shielding, causing the lower limit of the attenuation efficiency to drop to 73.0%.

[0107] In contrast, the examples that underwent synergistic treatment with ultrasonic cavitation and electrostatic fields all showed higher attenuation efficiency in areas prone to sweating. Example 1 was treated for 3 minutes at a 40 kHz ultrasonic frequency and a -20 kV electrostatic field strength, and the attenuation efficiency range was increased to 82.5% to 98.0%. This is because the impact force generated by the cavitation collapse of 40 kHz high-frequency ultrasound in deoxygenated anhydrous ethanol effectively broke up the brittle tungsten oxide agglomerates, while the simultaneously applied electrostatic field made the surface of the KH560-modified bismuth oxide particles positively charged, overcoming the agglomeration tendency through directional electrostatic repulsion, and achieving uniform dispersion of the particles in the matrix. These highly dispersed particles provide a continuous and weak area-free ray shielding path, thereby demonstrating stable and efficient attenuation capabilities in the entire energy range of 30-100 keV.

[0108] Example 5 By increasing the electrostatic field strength to -25 kV and extending the treatment time to 5 min, the attenuation efficiency of the sweat-prone area reached a peak of 86.5%-99.0%, while the air permeability (1350.6 mm / s) and water vapor permeability (2300.7 g / m 2 · 24 h) also achieved optimal results for all samples. This is due to the highly dispersed particles achieving equivalent shielding at a low areal density. Furthermore, the micropores formed by the precipitation of CO2 at the interface enrichment layer during supercritical CO2 treatment are less susceptible to blockage, creating more effective ventilation channels. Furthermore, the evenly dispersed particles facilitate uniform stress transfer within the polypropylene matrix. Combined with the enhanced interfacial bonding strength achieved by KH560 modification, the elongation at break increased to 62.5%, resulting in excellent fiber toughness and a more uniform internal structure.

[0109] In addition, the comparative example 1 was needle-punched, but due to the lack of particle dispersion by the synergistic treatment of ultrasonic cavitation and electrostatic field, the elongation at break was only 41.0%. 2 The high density and shallow depth of 1.6 mm make the fabric structure tight, but the air permeability and elongation at break are both low. 2 The combination of a medium density and a deeper penetration depth of 1.8 mm enables the fibers carrying tungsten carbide particles to fully utilize the mechanical anchoring effect of the angular structure, building a more stable and elastic network skeleton in three-dimensional space, achieving a maximum elongation at break of 62.5%. The formed stable support framework also ensures that the integrity of the fabric will not be weakened after the subsequent supercritical carbon dioxide treatment to generate a microporous structure, achieving high air permeability. Examples 3 and 9 respectively use a higher needle punching density (150 needles / cm 2) or deeper penetration depth (2.0 mm), but the elongation at break was much lower than that in Example 5. This was because the pores in the fiber web were over-squeezed, some of the connected pores became closed, and the flow paths of gas and water vapor were blocked.

[0110] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the content of the specification and must be determined according to the scope of the claims.

Claims

1. A method for preparing lightweight, lead-free, breathable nuclear protective clothing, characterized in that: The following steps are involved: Step 1: BWWT composite shielding particles are blended with polypropylene to prepare a masterbatch, and the masterbatch is modified and melt-spun to form a composite fiber; The composite fibers are combed and directionally stacked into a composite fiber web, and then needle-punched and treated with supercritical carbon dioxide to produce a 3D composite fiber needle-punched fabric. The masterbatch is modified and melt-spun to obtain spun fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment. Step 2: coating the modified polyimide film with a bismuth solution twice and hot pressing the film to produce a lightweight lead-free protective material; Step 3: Connect the 3D composite fiber needle-punched fabric and the lightweight lead-free protective material through a sewing process to produce a nuclear protective suit; The ultrasonic cavitation and electrostatic field synergistic treatment is carried out in an inert environment at an ultrasonic frequency of 38 to 42 kHz and an electrostatic field strength of -30 to -20 kV for 3 to 7 minutes, and the acupuncture treatment adopts 120 punctures / cm 2 Up to 150 thorns / cm 2 The needle density is between 1.6 and 2.0 mm.

2. The preparation method according to claim 1, characterized in that The preparation method of the 3D composite fiber needle-punched fabric includes: S1: Melt-blending and extruding BWWT composite shielding particles with polypropylene to obtain a masterbatch; S2: Surface modification of the masterbatch is followed by melt spinning to form nascent fibers, which are then subjected to ultrasonic cavitation and electrostatic field synergistic treatment, and then heat-stretched to obtain composite fibers; S3: Cutting the composite fibers to a fixed length and combing them into a single-layer fiber web, and directionally stacking the single-layer fiber webs to obtain a composite fiber web; S4: performing air curtain guidance and needle punching treatment on the composite fiber web to obtain a needle punched fabric intermediate; S5: performing gradient hot pressing and pressure-maintaining cooling on the preheated needle-punched fabric intermediate to obtain a compressed and shaped fabric; S6: The compressed and shaped fabric is subjected to supercritical carbon dioxide treatment and rapid pressure relief, and then subjected to hot roller rolling and cooling and shaping to obtain a 3D composite fiber needle-punched fabric; The gradient hot pressing includes the following three consecutive pressure stages: In the first stage, a pressure of 0.4–0.6 MPa is applied for 8–12 s; In the second stage, a pressure of 2.5–3.0 MPa was applied for 17–23 s; In the third stage, a pressure of 5.0-6.0 MPa is applied for 25-35 s.

3. The preparation method according to claim 2, characterized in that The preparation method of masterbatch includes: 55-65 wt% bismuth oxide, 10-20 wt% tungsten oxide, 10-20 wt% tungsten carbide and 5-15 wt% tantalum oxide were dry-mixed at 750-850 rpm for 10-15 min to form BWWT composite shielding particles; 30-40 wt% polypropylene and 60-70 wt% BWWT composite shielding particles are melt-blended at a temperature of 165-190 °C and a rotation speed of 110-130 rpm for 3-5 min. After filtering to remove impurities with a diameter greater than 50 μm, the melt is extruded into strips through a 1-3 mm die hole, passed into a 22-28 °C circulating water cooling tank for solidification, and finally cut into cylindrical masterbatches with a length of 1-6 mm and a diameter of 1-3 mm.

4. The preparation method according to claim 2, characterized in that The masterbatch modification method includes: adding the masterbatch into an anhydrous ethanol solution of KH560 silane coupling agent with a pH of 4.0-5.0 and a concentration of 1-3 wt%, and refluxing for 80-100 minutes at 65-75°C and a stirring speed of 180-220 rpm; filtering after the reaction, rinsing with anhydrous ethanol 3-5 times, and vacuum drying at 75-85°C for 3-5 hours to obtain a modified masterbatch.

5. The preparation method according to claim 2, characterized in that The heat stretching shaping method includes introducing the as-spun fiber after the coordinated treatment of ultrasonic cavitation and electrostatic field into a 130-140°C environment, regulating the orientation crystallization at a stretching ratio of 1.9-2.3, and shaping it with a cooling roller at 22-28°C to obtain a composite fiber.

6. The preparation method according to claim 2, characterized in that The cut-to-length method includes cutting the composite fibers into 5.0 to 8.0 cm staple fiber bundles.

7. The preparation method according to claim 2, characterized in that The single-layer fiber web has a unit area mass of 0.045 to 0.055 g / cm 2 .

8. The preparation method according to claim 1, characterized in that The preparation method of the lightweight lead-free protective material comprises the following steps: M1: modifying the polyimide film to obtain a modified polyimide film; M2: A bismuth solution is coated on a modified polyimide film to form a wet film, which is then heat-pressed to obtain a composite film intermediate with a bismuth coating. M3: The bismuth solution is coated again on the surface of the composite membrane intermediate to form a wet film. After hot pressing, a composite membrane with a thickened bismuth coating is obtained; M4: The composite film is subjected to calendering treatment and then cooled and shaped to obtain a lightweight lead-free protective material; The hot pressing treatment includes preheating at 265-275°C and 0.05-0.2 MPa for 19-21 minutes, then heating to 290-300°C and 24-26 MPa and pressing for 14-16 minutes.

9. The preparation method according to claim 1, characterized in that The suturing process includes the following steps: T1: Cut the 3D composite fiber needle-punched fabric and lightweight lead-free protective material into pieces, cut the pieces and spray the functional adhesive layer; T2: sew the processed pieces together; T3: Apply hot melt tape to the seams and pulse heat press to bond; T4: Melt seal the seam.

10. A lightweight, lead-free, breathable nuclear protective clothing, prepared by the preparation method according to any one of claims 1 to 9, characterized in that: It includes parts prone to sweating and other parts, wherein the parts prone to sweating are made of 3D composite fiber needle-punched fabric, and the other parts are made of lightweight lead-free protective materials.

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