Laminated multifunctional protective material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of nuclear radiation protection materials, and provides a laminated multifunctional protection material and a preparation method and application thereof.The preparation method comprises the steps that S1, a ray shielding filler and a wear-resistant and acid-alkali-resistant filler are subjected to ball milling and then subjected to surface hydrophobization modification treatment, and a composite material is obtained; obtaining a modified ray shielding filler dispersion and a modified wear-resistant acid-base-resistant filler dispersion; s2, mixing the modified ray shielding filler dispersion with pre-vulcanized neoprene latex, and then adding a thickening agent to obtain first composite latex; mixing the modified wear-resistant acid-base-resistant filler dispersion with prevulcanized neoprene latex, and then adding a thickening agent to obtain second composite latex; s3, dipping treatment is adopted, and a composite layer is obtained; s4, the surface of the composite layer is coated with acrylic acid modified polyvinylidene fluoride emulsion, a multi-effect protection layer is formed through drying, and the laminated multifunctional protection material is obtained; the material prepared by the method has excellent radiation shielding, chemical corrosion resistance and wear resistance, and is especially suitable for preparing high-reliability protective gloves for nuclear glove boxes.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation protection materials technology, and more specifically, to a multi-functional layered protective material, its preparation method, and its application. Background Technology

[0002] Handling radioactive materials in laboratory or industrial environments requires specialized equipment to ensure safety, precision, and controllability. Nuclear glove boxes, as sealed working environments, provide dual protection for the handling of high-risk materials: protecting operator safety while effectively sealing radioactive materials. These glove boxes are sealed containers that physically isolate radioactive materials for safe handling; the side walls integrate operating gloves, allowing operators to indirectly handle hazardous materials, ensuring no leakage of harmful substances and minimizing radiation exposure and contamination risks. Typical applications include: the dispensing of radioactive isotopes in the medical field; the solidification of transuranic elements (TRU) in nuclear waste management and treatment; and the detection of spent fuel rods (U-Pu co-processing) and MOX fuel pellet preparation in nuclear fuel recycling.

[0003] As protective gloves are a critical component of nuclear glove boxes, they must meet certain radiation protection requirements, as well as adequate mechanical properties such as abrasion and puncture resistance; they must also be resistant to acid and alkali penetration and chemicals. Currently, the manufacturing methods for protective gloves used in nuclear glove boxes are typically molding and impregnation methods. Specifically: Compression molding is often preferred due to its high precision, efficiency, and stability. For example, patent CN117757168A discloses a glove box radiation protection glove. Specifically, it uses chloroprene rubber, EPDM rubber, and chlorosulfonated polyethylene rubber as base materials, silane coupling agent modified nano-tungsten powder or nano-bismuth powder as the shielding body, and barium sulfate as an acid and alkali resistant reinforcing agent. Finally, it uses compression molding to prepare a protective glove with good softness, mechanical properties, and acid and alkali corrosion resistance. However, due to the limitations of the mold design, the molded glove cannot distinguish between left and right hands, and the fit and operating comfort are poor. More importantly, the compression molding process makes it difficult to achieve multi-layered composite structures with functional gradients, which limits the further improvement of its overall performance.

[0004] Latex impregnation can achieve multi-layer material composites, thus giving gloves different functions and producing gloves with good softness, making them easy for operators to handle. However, it has the following drawbacks: First, the high-density radiation protection fillers (such as tungsten, bismuth and their oxides) have a large density difference with the latex, making them prone to sedimentation and agglomeration in the latex. This leads to uneven filler dispersion and unstable shielding performance, especially under high load conditions where the filler content reaches 15% to 25%. Second, the interfacial compatibility between different material layers (such as rubber layer and fluoropolymer layer) is poor, the bonding force is weak, and interlayer delamination is prone to occur, seriously affecting the product's service life and reliability. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the core objective of the present invention is to solve the technical problems of high-density protective fillers being prone to sedimentation and agglomeration in latex, weak interfacial bonding of multilayer composite materials, and the difficulty of existing materials in simultaneously providing radiation protection and chemical protection.

[0006] This invention is achieved through the following technical solution: The first objective of this invention is to provide a method for preparing a multi-functional laminated protective material, comprising the following preparation steps: S1. The radiation shielding filler and the wear-resistant and acid-alkali resistant filler are ball-milled and refined, and then surface hydrophobic modification treatment is performed on them respectively to obtain modified radiation shielding filler dispersion and modified wear-resistant and acid-alkali resistant filler dispersion. S2. The modified radiation shielding filler dispersion is mixed with pre-vulcanized chloroprene latex, and then a thickener is added to obtain a first composite latex for forming a radiation shielding layer; the modified wear-resistant and acid- and alkali-resistant filler dispersion is mixed with pre-vulcanized chloroprene latex, and then a thickener is added to obtain a second composite latex for forming a secondary protective layer. The viscosity of both the first composite latex and the second composite latex is 100 mPa·s to 300 mPa·s. S3. The first composite latex and the second composite latex are sequentially molded and vulcanized on a mold by multiple impregnation processes to obtain a composite layer. S4. An acrylic-modified polyvinylidene fluoride emulsion is coated on the surface of the composite layer, and after drying, a multi-effect protective layer is formed, resulting in a layered multi-functional protective material.

[0007] Preferably, the multiple impregnation treatment includes: S31. The hand-shaped mold coated with coagulant is first impregnated with the first composite latex, and then dried and shaped to obtain a radiation shielding layer. S32. The second composite latex is then used for a second impregnation treatment, followed by vulcanization treatment, to obtain a secondary protective layer composited on the outer surface of the radiation shielding layer. In step S4, the acrylic-modified polyvinylidene fluoride emulsion is coated onto the outer surface of the secondary protective layer, and then dried to obtain the multi-effect protective layer.

[0008] Preferably, the vulcanization treatment is performed at a temperature of 110°C to 130°C for a time of 20 to 40 minutes.

[0009] Preferably, in step S1, the ball-milled and refined radiation shielding filler and the wear-resistant and acid-alkali-resistant filler are respectively heated and stirred, and then an ethanol solution of silane coupling agent is added dropwise and the reaction is carried out at a constant temperature to obtain the modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali-resistant filler dispersion, respectively.

[0010] Preferably, in step S1, the temperature of the heating and stirring treatment is 50℃~70℃, the stirring speed is 50~300rpm, and the duration of the heat preservation reaction is 30~90min.

[0011] Preferably, in step S4, the drying process is carried out at a temperature of 70°C to 90°C for a time of 10 to 30 minutes.

[0012] Preferably, the ethanol solution of the silane coupling agent has a mass concentration of 5% to 15%.

[0013] Preferably, the particle size of both the modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali-resistant filler dispersion after ball milling is <500nm; the solid content of both the modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali-resistant filler dispersion is 60% to 80%.

[0014] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane or γ-(methacryloyloxy)propyltrimethoxysilane.

[0015] Preferably, the amount of silane coupling agent is 1% to 3% based on the mass of the radiation shielding filler; The amount of silane coupling agent used is 1% to 3% based on the mass of the wear-resistant and acid-alkali-resistant filler.

[0016] Preferably, the preparation steps of the pre-vulcanized chloroprene latex include: mixing chloroprene latex with vulcanizing agent, accelerator, activator and antioxidant, and then performing a constant temperature curing reaction at 40℃~60℃ for 6~24h to obtain the pre-vulcanized chloroprene latex.

[0017] Preferably, the vulcanizing agent is zinc oxide and / or sulfur; the accelerator is vinyl thiourea and / or zinc diethyl dithiocarbamate; the activator is magnesium oxide; and the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer or 2-mercaptobenzimidazole.

[0018] More preferably, the vulcanizing agent is composed of zinc oxide and sulfur in a mass ratio of 3 to 5:1.

[0019] Preferably, the thickener is one or more of sodium polyacrylate, hydroxymethyl cellulose, or guar gum; the amount of the thickener added is 0.5% to 2% based on the total mass of the composite latex.

[0020] Preferably, based on 100 parts of the dry weight of the chloroprene latex, the amount of vulcanizing agent added is 3 to 8 parts, the amount of accelerator added is 0.5 to 2 parts, the amount of activator added is 4 to 6 parts, and the amount of antioxidant added is 1 to 3 parts.

[0021] Preferably, based on 100 parts of the total dry mass of the first composite latex, the amount of the modified radiation shielding filler dispersion added is 40-80 parts, and the dry mass of the pre-vulcanized chloroprene latex is 20-60 parts.

[0022] Preferably, based on 100 parts of the total dry mass of the second composite latex, the amount of the modified wear-resistant and acid-alkali resistant filler dispersion added is 10 to 30 parts, and the dry mass of the pre-vulcanized chloroprene latex is 70 to 90 parts.

[0023] Preferably, the preparation steps of the acrylic-modified polyvinylidene fluoride emulsion include: mixing and emulsifying vinylidene fluoride monomer with acrylate monomer, deionized water, emulsifier and initiator, and then carrying out emulsion copolymerization reaction under the conditions of 60℃~85℃ and 1.0MPa~3.0MPa to obtain the acrylic-modified polyvinylidene fluoride emulsion.

[0024] Preferably, the mass ratio of the vinylidene fluoride monomer to the acrylate monomer is (50:50) to (90:10).

[0025] Preferably, in the preparation process of the acrylic-modified polyvinylidene fluoride emulsion, the addition ratio of each component is based on 100 parts of the total mass of the polyvinylidene fluoride monomer and the acrylate monomer, 120-200 parts of deionized water, 1-3 parts of emulsifier, and 0.5-2 parts of initiator.

[0026] More preferably, the mass ratio of the vinylidene fluoride monomer to the acrylate monomer is 80:20.

[0027] Preferably, the acrylate monomer is one or more of butyl acrylate or methyl methacrylate.

[0028] Preferably, the emulsifier is sodium dodecyl sulfate; the initiator is ammonium persulfate or potassium persulfate.

[0029] Preferably, the coagulant is an aqueous solution of calcium nitrate or calcium chloride in alcohol, with a mass concentration of 10% to 30%.

[0030] The radiation protection filler is one or more of bismuth, bismuth oxide, tungsten, and tungsten oxide; the wear-resistant and acid-alkali resistant filler is one or more of barium sulfate, carbon black, and silica.

[0031] The second objective of this invention is to provide a multi-functional protective material prepared by the above method, comprising the radiation shielding layer, the secondary protective layer, and the multi-effect protective layer sequentially composited from the inside out; The radiation shielding layer comprises neoprene rubber and radiation shielding filler, wherein the thickness of the radiation shielding layer is 0.7–0.9 mm; The secondary protective layer comprises neoprene rubber and wear-resistant, acid and alkali-resistant fillers, wherein the thickness of the secondary protective layer is 0.1–0.2 mm; The multi-functional protective layer comprises acrylic-modified polyvinylidene fluoride, wherein the thickness of the multi-functional protective layer is 0.02–0.05 mm; The average thickness of a single layer of the protective gloves is 1.0±0.2mm, and the lead equivalent is 0.1~0.2mmPb.

[0032] The third objective of this invention is to provide the application of the above-mentioned multifunctional protective material in the preparation of protective gloves for a multifunctional nuclear glove box, wherein the protective gloves have a length of 800±5mm, a cuff diameter of 200±2mm, and a rolled edge diameter of 5±0.5mm.

[0033] The inventive concept of this invention lies in: First, this invention uses ball milling to break micron-sized fillers down to the nanoscale (<500nm), greatly increasing the specific surface area. The subsequent "surface hydrophobic modification" utilizes silane coupling agents to construct hydrophobic layers on the surfaces of various filler particles, effectively reducing their surface energy. This synergistic effect at both the physical (reducing particle size) and chemical (changing surface properties) levels ultimately yields high-solids-content (60%–80%) and long-term stable modified radiation-shielding filler dispersions and modified wear-resistant and acid-alkali-resistant filler dispersions, laying the foundation for the subsequent preparation of homogeneous functional latexes.

[0034] Furthermore, by mixing the stable modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali resistant filler dispersion with pre-vulcanized chloroprene latex, the functional fillers were precisely introduced into the rubber matrix. Furthermore, by adding a thickener and precisely controlling the viscosity of each composite latex within the range of 100–300 mPa·s, the sedimentation tendency of the fillers was suppressed from a rheological perspective, ensuring the feasibility of the impregnation process and the uniformity of film formation. This endowed the final product with the required radiation shielding and wear-resistant and acid-alkali resistant properties.

[0035] Most importantly, this invention creatively introduces acrylic-modified polyvinylidene fluoride (PVDF) as the outermost layer, using the acrylic component as a "molecular anchor." One end forms a strong chemical bond with the chloroprene rubber layer, while the other end is compatible with the PVDF molecular chain, thus constructing a stable transition layer at the interface of two materials with different properties. The modified interface layer can effectively buffer the internal stress caused by the difference in the thermal expansion coefficients of the materials and external stress, effectively preventing interlayer delamination. This solves the long-standing problem of rubber-fluoropolymer interface bonding in the field. Furthermore, even if the outermost PVDF layer fails partially due to accidental damage, the inner secondary protective layer can still provide reliable protection, thus forming a unique failure protection mechanism.

[0036] Furthermore, this invention employs an impregnation method combined with a precisely controlled multi-layer structure: a radiation shielding layer (0.7–0.9 mm, high filler content), a secondary protective layer (0.1–0.2 mm, balanced filler content), and a multi-effect protective layer (0.02–0.05 mm, pure PVDF). This specific design with functional gradients allows each layer to perform its own function while working collaboratively, achieving a comprehensive performance balance that cannot be achieved by traditional homogeneous materials or simple composite structures.

[0037] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: (1) This invention solves the problem of high-density filler settling in latex by ball milling and surface modification, and achieves uniform dispersion of protective filler by impregnation method, thus ensuring the stability and consistency of radiation shielding performance.

[0038] (2) The present invention constructs a functionally graded composite layer by multiple impregnations, which ensures radiation protection performance while taking into account the softness and operational comfort of the material.

[0039] (3) The present invention utilizes acrylic modified PVDF as a multi-effect protective layer, which achieves a firm bond with the rubber matrix through interface bridging, giving the material excellent wear resistance and chemical resistance; the multi-layer structure design also has a failure protection function, even if the outer layer is damaged, the secondary protective layer can still provide effective protection, significantly extending the service life of the gloves. Attached Figure Description

[0040] Figure 1 This is the process flow framework of the present invention.

[0041] Figure 2 This is a schematic diagram showing the layer distribution of the protective gloves in the multilayered nuclear glove box of the present invention.

[0042] Figure labels: 1-Multi-effect protective layer, 2-Secondary protective layer, 3-Radiation shielding layer. Detailed Implementation

[0043] Example 1 This embodiment provides a method for preparing a layered nuclear glove box protective glove, the specific steps of which are as follows: S1. Preparation of modified filler dispersion: Modified radiation shielding filler dispersion: Radiation protection filler (tungsten powder and tungsten oxide powder mixed at a mass ratio of 1:1) was subjected to high-energy ball milling to control the maximum particle size <500nm. Then, the ball-milled radiation protection filler was stirred at 60℃ and 300rpm, and a 10% (w / w) ethanol solution of γ-aminopropyltriethoxysilane (CAS No.: 919-30-2) was slowly added dropwise (the amount of silane coupling agent was 2% of the mass of the radiation protection filler). The reaction was kept at this temperature for 60min to obtain a modified radiation shielding filler dispersion with a solid content of 70%.

[0044] Modified wear-resistant and acid-alkali-resistant filler dispersion: A wear-resistant and acid-alkali-resistant filler (barium sulfate and silica mixed at a mass ratio of 3:2) was subjected to high-energy ball milling to control the maximum particle size to <500 nm. The ball-milled filler was then stirred at 60℃ and 400 rpm, and a 10% (w / w) ethanol solution of γ-aminopropyltriethoxysilane (the amount of silane coupling agent was 2% of the mass of the wear-resistant and acid-alkali-resistant filler) was slowly added dropwise. The reaction was maintained at this temperature for 60 min to obtain a modified wear-resistant and acid-alkali-resistant filler dispersion with a solid content of 70%.

[0045] S2. Preparation of pre-vulcanized chloroprene latex: Based on 100 parts by weight of dry chloroprene latex, 5 parts zinc oxide and 1 part sulfur (mass ratio 5:1) were used as vulcanizing agents, 1 part vinyl thiourea as an accelerator, 5 parts magnesium oxide as an activator, and 2 parts 2,2,4-trimethyl-1,2-dihydroquinoline polymer (CAS No.: 26780-96-1) as an antioxidant. The above raw materials were mixed with chloroprene latex and cured at 50°C for 12 hours to obtain pre-vulcanized chloroprene latex.

[0046] S3. Preparation of composite latex: First composite latex: The modified radiation shielding filler dispersion and pre-vulcanized chloroprene latex are mixed at a dry mass ratio of 60:40, and sodium polyacrylate at 1% of the total mass of the composite latex is added as a thickener to obtain a first composite latex with a viscosity of 200 mPa·s.

[0047] Second composite latex: The modified wear-resistant and acid and alkali-resistant filler dispersion is mixed with pre-vulcanized chloroprene latex at a dry mass ratio of 10:90, and sodium polyacrylate is added as a thickener at 1% of the total mass of the composite latex to obtain a second composite latex with a viscosity of 200 mPa·s.

[0048] S4. Preparation of laminated protective gloves: The hand-shaped mold was immersed in a 20% calcium nitrate alcohol aqueous solution as a coagulant and then dried at 80°C for 1 minute. Then, a first immersion treatment was performed, followed by drying and shaping at 120°C for 1 minute to obtain a radiation shielding layer with a thickness of 0.8 mm. Subsequently, the hand-shaped mold with the radiation shielding layer was immersed again in a 20% calcium nitrate alcohol aqueous solution and dried at 80°C for 1 minute. Then, a second immersion treatment was performed, followed by vulcanization at 120°C for 30 minutes to form a secondary protective layer with a thickness of 0.15 mm on the outer surface of the radiation shielding layer. Subsequently, an acrylic-modified polyvinylidene fluoride (PVDF) emulsion was prepared and coated. Specifically, PVDF monomer and methyl methacrylate monomer (CAS No.: 80-62-6) were added to a reactor at a dry mass ratio of 1:1 (i.e., 50% PVDF and 50% methyl methacrylate). Sodium dodecyl sulfate (CAS No.: 151-21-3) at 2% of the total monomer mass was added as an emulsifier, along with appropriate amounts of deionized water and ammonium persulfate initiator. The emulsion copolymerization reaction was carried out at 75°C and 2.0 MPa to obtain a stable acrylic-modified PVDF emulsion. This emulsion was uniformly coated onto the outer surface of the aforementioned secondary protective layer and dried at 80°C for 20 min to form a multi-functional protective layer with a thickness of 0.03 mm, ultimately producing a layered nuclear glove box protective glove.

[0049] Example 2 The difference between this embodiment and Embodiment 1 lies in the adjustment of process parameters. The specific steps are as follows: In step S1, the solid content of the two modified filler dispersions is controlled to be 60%, the amount of silane coupling agent is 1% of the mass of the composite filler, and γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0) is selected as the modifier.

[0050] In step S2, the vulcanization system uses 3 parts zinc oxide, 1 part sulfur, 0.5 parts accelerator, 4 parts activator, and 1 part antioxidant. The curing temperature is controlled at 40℃, and the curing time is extended to 24 hours.

[0051] In step S3, the filler to latex mass ratio of the first composite latex is controlled to be 40:60, and the filler to latex mass ratio of the second composite latex is controlled to be 15:85; the viscosity of the first composite latex is adjusted to 100 mPa·s, and the viscosity of the second composite latex is adjusted to 100 mPa·s; hydroxymethyl cellulose is selected as the thickener.

[0052] In step S4, the thickness of the radiation shielding layer is controlled to be 0.7 mm, the thickness of the secondary shielding layer is 0.1 mm, and the thickness of the multi-effect shielding layer is 0.02 mm. A copolymer emulsion of 70% PVDF and 30% methyl methacrylate is used. The drying temperature is controlled at 70°C and the drying time is extended to 30 min.

[0053] Example 3 The difference between this embodiment and Embodiment 1 lies in the adjustment of process parameters. The specific steps are as follows: In step S1, the solid content of the two modified filler dispersions is controlled to be 80%, the amount of silane coupling agent is increased to 3% of the mass of the composite filler, and the radiation protection filler is a combination of bismuth powder and tungsten oxide powder.

[0054] In step S2, the vulcanizing agent is 8 parts zinc oxide, the amount of accelerator is increased to 2 parts, the amount of activator is increased to 6 parts, the amount of antioxidant is increased to 3 parts, the curing temperature is increased to 60℃, and the curing time is shortened to 6 hours.

[0055] In step S3, the filler to latex mass ratio of the first composite latex is controlled to be 80:20, and the filler to latex mass ratio of the second composite latex is controlled to be 30:70; the viscosity of the first composite latex is increased to 300 mPa·s, and the viscosity of the second composite latex is increased to 300 mPa·s; guar gum is selected as the thickener.

[0056] In step S4, the thickness of the radiation shielding layer is controlled to be 0.9 mm, the thickness of the secondary shielding layer is 0.2 mm, and the thickness of the multi-effect shielding layer is 0.05 mm. A copolymer emulsion of 90% PVDF and 10% methyl methacrylate is used. The vulcanization temperature is increased to 130°C, the vulcanization time is shortened to 20 min, the drying temperature is increased to 90°C, and the drying time is shortened to 10 min.

[0057] Example 4 The difference between this embodiment and Embodiment 1 lies in the adjustment of the packing system and monomers. The specific steps are as follows: In step S1, pure tungsten powder is selected as the radiation protection filler, and the ratio of barium sulfate to silica in the wear-resistant and acid-alkali resistant filler is adjusted to 4:1.

[0058] In step S4, a modified emulsion is obtained by copolymerizing 80% PVDF with 20% butyl acrylate (CAS No.: 141-32-2).

[0059] Example 5 The difference between this embodiment and Embodiment 1 lies in the selection of the packing combination and the monomers. The specific steps for the difference are as follows: In step S1, the radiation protection filler is a combination of bismuth oxide and tungsten powder, and the ratio of bismuth oxide to tungsten powder in the radiation protection filler is 1:4.

[0060] In step S4, a modified emulsion obtained by copolymerizing 80% PVDF and 20% methyl methacrylate is used.

[0061] Comparative Example 1 The difference between this comparative example and Example 1 is that it does not contain a multi-effect protective layer. The specific steps to differentiate them are as follows: The PVDF emulsion coating process in step S4 is omitted, and the protective gloves are obtained directly after the secondary protective layer is vulcanized.

[0062] Comparative Example 2 The difference between this comparative example and Example 1 is that it uses an unmodified PVDF emulsion. The specific difference is as follows: In step S4, a pure PVDF emulsion (without acrylic modification components) is used for coating.

[0063] Comparative Example 3 The difference between this comparative example and Example 1 is that neither of the fillers underwent surface modification treatment. The specific steps for distinguishing them are as follows: In step S1, the surface hydrophobic modification treatment is omitted, and the ball-milled composite fillers are directly used to prepare composite latex.

[0064] Comparative Example 4 The difference between this comparative example and Example 1 lies in the use of a traditional EPDM rubber molding process. The specific steps are as follows: Using ethylene propylene diene monomer (EPDM) rubber as the base material, and adding the same type and proportion of functional fillers as in Example 1, the protective gloves were prepared by compression molding at 150°C and 15MPa in a single process. The multi-layer structure was not constructed by impregnation and the gloves did not contain a PVDF multi-effect protective layer.

[0065] Experimental Example 1 Multiple groups of samples were prepared using the methods provided in Examples 1-5 and Comparative Examples 1-4, and various performance tests were conducted. The test results are shown in Table 1 below. The specific test items and test methods are as follows: (1) Wear resistance test Referring to GB / T21196.2-2007 "Textiles - Martindale Method for Determination of Abrasion Resistance of Fabrics - Part 2: Determination of Specimen Breakage", the specific test method is as follows: using a Martindale abrasion tester, apply a pressure of 9 kPa to the sample, record the number of frictions when the sample breaks, and convert it into an abrasion resistance grade (1-5, with higher grades indicating better abrasion resistance) according to the standard.

[0066] (2) Permeability test Referring to GB / T23462-2009 "Test Method for Chemical Penetration of Protective Clothing", the specific test method is as follows: use n-hexane, ethyl acetate, 40% sodium hydroxide, 96% sulfuric acid, and 65% nitric acid as test media, and conduct penetration tests at 23±2℃. Record the penetration of chemical substances within the time specified in the standard and rate them (1-6, with higher grades indicating better penetration resistance).

[0067] (3) Lead equivalent test Referring to GBZ / T 147-2002 "Determination of Attenuation Performance of X-ray Shielding Materials", the specific test method is as follows: place the detector in the radiation field and measure the dose rate after passing through the sample without a sample and after passing through the glove sample. Calculate the lead equivalent of the sample based on the shielding efficiency of standard lead sheets (thicknesses of 0.1 mm and 0.2 mm, respectively).

[0068] (4) Interlayer bonding strength test Referring to GB / T2791-1995 "Test Method for T-Peel Strength of Adhesives - Flexible Materials to Flexible Materials", the specific test method is as follows: Prepare a standard specimen, perform a T-peel test using a universal testing machine at a rate of 100 mm / min, and record the peel force per unit width (N / cm). (5) Thickness measurement Referring to GB / T3820-1997 "Determination of thickness of textiles and textile products", the specific test method is as follows: using a digital thickness gauge, multiple measurements are taken at various points on the sample under standard conditions (20±2℃, 65±2%RH) and the average value is taken.

[0069] (6) Mechanical property testing Referring to GB / T528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber", the specific test method is as follows: standard dumbbell-shaped specimens are prepared, and tensile strength, elongation at break, and other indicators are determined using an electronic tensile testing machine; all tests are conducted in a standard laboratory environment (temperature 23±2℃, relative humidity 50±5%), and five specimens are tested for each sample, and the average value is taken to ensure the accuracy and reproducibility of the test results.

[0070] Table 1 Results of various performance tests

[0071] As can be seen from the analysis of Table 1, the examples have achieved a comprehensive improvement over traditional products in key performance aspects. Specifically, firstly, in terms of the crucial organic solvent resistance performance, all examples using acrylic-modified PVDF multi-effect protective layers (such as Example 3, which has an ethyl acetate permeability resistance level of 5) are significantly better than Comparative Example 1 (level 3) without this layer, proving that this multi-effect protective layer is the key to overcoming the organic solvent resistance problem.

[0072] Secondly, acrylic acid modification played a decisive role in ensuring the interfacial bonding strength of the multilayer structure. For example, the bonding strength of the example group (interlayer bonding strength 12.8-16.5 N / cm) was higher than that of Comparative Example 2 (using unmodified PVDF, the bonding strength was only 8.5 N / cm). This verifies that the acrylic acid component, as a "molecular bridge", effectively solved the interfacial compatibility problem between PVDF and the rubber matrix.

[0073] Furthermore, by comprehensively comparing the effects of different formulations and processes, a clear optimal parameter range can be established. For example, Example 3 (PVDF to acrylate monomer mass ratio of 90:10) showed outstanding performance in terms of chemical resistance (especially reaching level 5 in 96% sulfuric acid environment) and lead equivalent (0.20 mmPb), demonstrating excellent overall performance balance.

[0074] Finally, the product of the present invention maintains excellent radiation protection and mechanical abrasion resistance (abrasion resistance level of 4 in Examples 1-5) while achieving high-level, sustainable protection against a wide range of chemicals, especially organic solvents that are difficult for traditional rubber materials to resist. Its overall performance is significantly better than that of the prior art.

Claims

1. A method for preparing a layered multifunctional protective material, characterized in that, The preparation steps include the following: S1. The radiation shielding filler and the wear-resistant and acid-alkali resistant filler are ball-milled and refined, and then surface hydrophobic modification treatment is performed on them respectively to obtain modified radiation shielding filler dispersion and modified wear-resistant and acid-alkali resistant filler dispersion. S2. The modified radiation shielding filler dispersion is mixed with pre-vulcanized chloroprene latex, and then a thickener is added to obtain a first composite latex for forming a radiation shielding layer; the modified wear-resistant and acid- and alkali-resistant filler dispersion is mixed with pre-vulcanized chloroprene latex, and then a thickener is added to obtain a second composite latex for forming a secondary protective layer. The viscosity of both the first composite latex and the second composite latex is 100 mPa·s to 300 mPa·s. S3. The first composite latex and the second composite latex are sequentially molded and vulcanized on a mold by multiple impregnation processes to obtain a composite layer. S4. An acrylic-modified polyvinylidene fluoride emulsion is coated on the surface of the composite layer, and after drying, a multi-effect protective layer is formed, resulting in a layered multi-functional protective material.

2. The method for preparing the layered multifunctional protective material according to claim 1, characterized in that, The multiple impregnation treatments include: S31. The hand-shaped mold coated with coagulant is first impregnated with the first composite latex, and then dried and shaped to obtain a radiation shielding layer. S32. The second composite latex is then used for a second impregnation treatment, followed by vulcanization treatment, to obtain a secondary protective layer composited on the outer surface of the radiation shielding layer. In step S4, the acrylic-modified polyvinylidene fluoride emulsion is coated onto the outer surface of the secondary protective layer, and then dried to obtain the multi-effect protective layer.

3. The method of claim 1, wherein the laminate multifunctional protective material is prepared by the steps of: In step S1, the ball-milled and refined radiation shielding filler and the wear-resistant and acid-alkali-resistant filler are heated and stirred respectively, and then an ethanol solution of silane coupling agent is added dropwise and the reaction is carried out at a constant temperature to obtain the modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali-resistant filler dispersion respectively. The particle size of both the radiation shielding filler and the wear-resistant and acid-alkali resistant filler after ball milling is <500nm; the solid content of both the modified radiation shielding filler dispersion and the modified wear-resistant and acid-alkali resistant filler dispersion is 60% to 80%.

4. The method of claim 1, wherein the laminate multifunctional protective material is prepared by the steps of: The silane coupling agent is γ-aminopropyltriethoxysilane or γ-(methacryloyloxy)propyltrimethoxysilane.

5. The method for preparing the layered multifunctional protective material according to claim 1, characterized in that, The preparation steps of the pre-vulcanized chloroprene latex include: mixing chloroprene latex with vulcanizing agent, accelerator, activator and antioxidant, and then performing a constant temperature curing reaction at 40℃~60℃ for 6~24h to obtain the pre-vulcanized chloroprene latex. Of which, based on 100 parts of the dry weight of the chloroprene latex, the amount of vulcanizing agent added is 3 to 8 parts, the amount of accelerator added is 0.5 to 2 parts, the amount of activator added is 4 to 6 parts, and the amount of antioxidant added is 1 to 3 parts. Based on a total dry mass of 100 parts for the first composite latex, the amount of the modified radiation shielding filler dispersion added is 40-80 parts, and the dry mass of the pre-vulcanized chloroprene latex is 20-60 parts. Based on a total dry mass of 100 parts for the second composite latex, the amount of the modified wear-resistant and acid- and alkali-resistant filler dispersion added is 10 to 30 parts, and the dry mass of the pre-vulcanized chloroprene latex is 70 to 90 parts.

6. The method for preparing the layered multifunctional protective material according to claim 1, characterized in that, The preparation steps of the acrylic acid modified polyvinylidene fluoride emulsion include: mixing and emulsifying vinylidene fluoride monomer with acrylate monomer, deionized water, emulsifier and initiator, and then carrying out emulsion copolymerization reaction under the conditions of 60℃~85℃ and 1.0MPa~3.0MPa to obtain the acrylic acid modified polyvinylidene fluoride emulsion.

7. The method for preparing the layered multifunctional protective material according to claim 6, characterized in that, The mass ratio of the vinylidene fluoride monomer to the acrylate monomer is (50:50) to (90:10). The composition comprises, based on a total mass of 100 parts of the vinylidene fluoride monomer and the acrylate monomer, 120-200 parts of deionized water, 1-3 parts of emulsifier, and 0.5-2 parts of initiator.

8. The method for preparing the layered multifunctional protective material according to claim 2, characterized in that, The radiation protection filler is one or more of bismuth, bismuth oxide, tungsten, and tungsten oxide; the wear-resistant and acid-alkali resistant filler is one or more of barium sulfate, carbon black, and silica.

9. The laminated multi-functional protective material produced by the method of any one of claims 1 to 8, characterized by, It includes the radiation shielding layer, the secondary shielding layer, and the multi-effect shielding layer, which are sequentially combined from the inside out. The radiation shielding layer comprises neoprene rubber and radiation shielding filler, wherein the thickness of the radiation shielding layer is 0.7–0.9 mm; The secondary protective layer comprises neoprene rubber and wear-resistant, acid and alkali-resistant fillers, wherein the thickness of the secondary protective layer is 0.1–0.2 mm; The multi-functional protective layer comprises acrylic-modified polyvinylidene fluoride, wherein the thickness of the multi-functional protective layer is 0.02–0.05 mm; The average thickness of a single layer of the protective gloves is 1.0±0.2mm, and the lead equivalent is 0.1~0.2mmPb.

10. The application of the laminated multifunctional protective material as described in claim 9 in the preparation of laminated nuclear glove box protective gloves, characterized in that, The protective gloves are 800±5mm long, have a cuff diameter of 200±2mm, and a rolled edge diameter of 5±0.5mm.

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