Lightweight electromagnetic shielding multi-element metal fabric and method of making same

Abstract

The present application provides a lightweight electromagnetic shielding multi-element metal fabric and a preparation method thereof. The fabric prepared by the present application has a wide frequency band of electromagnetic protection and strong protection effect, and the combination of nickel silver and the base cloth is firm, and has good wear resistance and oxidation resistance, effectively combining the advantages of silver and nickel. The advantages of silver are strong conductivity and good shielding effect, but the disadvantages are poor friction resistance, easy oxidation, fast shielding performance decay with washing or time, high cost, and nickel has the advantages of friction resistance, not easy to oxidize and not easy to decay. The nickel is wrapped outside the silver, which can effectively protect the silver from friction, oxidation and shielding decay. The cost of nickel is relatively low. The multi-element metal fabric prepared has a weight of 65-68g / m 2 , and a comfortable hand feeling, which is not different from ordinary cloth.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic radiation protection materials and electromagnetic radiation damage protection, specifically relating to lightweight electromagnetic shielding multi-metal fabrics and their preparation methods. Background Technology

[0002] Studies have confirmed that certain doses of electromagnetic radiation can cause significant damage to humans and animals, leading to multi-system damage, primarily affecting the central nervous system and reproductive system. For example, 30 mW / cm²... 2 High-frequency shortwave radiation can cause spatial learning and memory impairment and inhibition of brain electrical activity in rats, as well as reduce the sperm motility and viability in the epididymis of rats.

[0003] Among numerous electromagnetic protection measures, wearing electromagnetic protective clothing is the most direct and effective for personal protection, and research on protective materials is fundamental to ensuring the success of such clothing. Currently, while there are many types of electromagnetic protective materials and clothing, their quality varies greatly, and their protective effects need improvement. Most anti-radiation clothing on the market is for civilian use, primarily targeting pregnant women. While it offers a certain level of protection, protective clothing for specific occupational groups or military applications has higher requirements, necessitating high strength, wide coverage, lightweight softness, high water resistance, and low shielding effectiveness attenuation. Therefore, fabrics with electromagnetic radiation shielding capabilities require further improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a lightweight electromagnetic shielding multi-metal fabric and its preparation method.

[0005] The lightweight electromagnetic shielding multi-metal fabric provided by this invention is prepared by a method comprising the following steps:

[0006] (1) Add palladium sulfate and sodium pyrophosphate to a hexamethylenetetramine solution, mix, and immerse the greige fabric after OP-10 cleaning in the resulting solution to form a metal carrier on the surface of each fiber bundle.

[0007] (2) Prepare a silver ammonia solution using pure water, a mixture of silver nitrate and silver cyanide, and ammonia. Immerse the fabric with the metal carrier formed on its surface in the silver ammonia solution, add formaldehyde dilution and EDTA mixture, and soak it to allow silver ions to form a metallic silver layer on the fabric surface under catalysis. When the resistivity of the fabric reaches 30-50 Ω•cm, remove the fabric to terminate the reaction. Then wash the fabric in a sodium hydroxide and sodium hypophosphite solution.

[0008] (3) The fabric treated in step (2) is cleaned with OP-10 aqueous solution to remove oil, and then cleaned with deionized water. The cleaned fabric is added to nickel sulfate aqueous solution, boric acid and hexamethylenetetramine are added, and the reaction is carried out. Nickel chloride, sodium aminosulfonate, sodium dodecylbenzenesulfonate and sodium tetraborate are added, and the temperature is raised to 80-90°. Under the action of palladium catalysis, a chemical plating reaction occurs. The nickel in the solution is reduced and deposited on the catalytically active fabric and fully combines with the metallic silver to obtain metallized silver nickel fiber fabric.

[0009] (4) Immerse the obtained metallized silver-nickel fiber fabric in a neutral solution, add phenolphthalein solution to the neutral solution, soak for 20-40 minutes, and finally clean the fiber fabric with cleaning solution and dry it.

[0010] In step (1) of the above method, the fabric is cleaned with an OP-10 aqueous solution at 25-35°C, wherein the mass concentration of OP-10 in the OP-10 aqueous solution is 1%.

[0011] The fabric may specifically be a double-threaded nylon fabric; the fabric weight is 45g / m². 2 ;

[0012] The concentration of palladium sulfate in the resulting solution can be 5-6 g / L, specifically 5.5 g / L;

[0013] The concentration of sodium pyrophosphate can be 0.5-5 g / L, specifically 2 g / L;

[0014] The mass concentration of hexamethylenetetramine in the hexamethylenetetramine solution is 5-15%, specifically 10%.

[0015] The soaking temperature can be 50-80°C, specifically 70°C, and the soaking time can be 20-60 minutes, specifically 30 minutes.

[0016] In step (2) of the above method, before the fabric with the metal carrier formed on its surface is immersed in the silver ammonia solution, it is further included in the operation of cleaning it with hydrogen peroxide solution and potassium chloride solution in sequence;

[0017] The mass concentration of the hydrogen peroxide solution is 27-40%, specifically 38%.

[0018] The mass concentration of the potassium chloride solution can be 5%-15%;

[0019] The ratio of pure water, silver nitrate and silver cyanide mixture, and ammonia water can be 20-30 L : 18-22 g : 0.024-0.036 L, specifically 25 L : 20 g : 0.03 L;

[0020] In the mixture of silver nitrate and silver cyanide, the weight percentage of silver cyanide is 1-5%, specifically 3%.

[0021] The mass concentration of the formaldehyde dilution is 36%.

[0022] Based on the mass of 1 L of silver ammonia solution, the amount of formaldehyde diluent added is 4%, and the amount of EDTA added is 4-6%.

[0023] The soaking time can be 20-40 minutes, specifically 30 minutes;

[0024] The silver ammonia solution is prepared by adding sodium hydroxide aqueous solution to a silver nitrate solution containing silver cyanide of a certain concentration to obtain a precipitate, then adding ammonia water dropwise while shaking until the precipitate just dissolves to obtain the silver ammonia solution; wherein the mass concentration of silver nitrate in the silver nitrate solution is generally 5%;

[0025] This invention uses silver nitrate containing a small amount of silver cyanide as a raw material, aiming to slow down the rate of silver deposition and obtain a uniform silver layer.

[0026] The temperature during the silver ammonia solution treatment in this invention (referring to the soaking temperature in step (2)) is generally 60°C.

[0027] In the sodium hydroxide and sodium hypophosphite solution, the mass concentration of sodium hydroxide is 5% and the mass concentration of sodium hypophosphite is 2%.

[0028] In step (3), the concentration of nickel sulfate in the nickel sulfate aqueous solution is 50-60 g / L, specifically 55 g / L;

[0029] The final concentration of the boric acid is 2-5 g / L (mass concentration), specifically 3 g / L;

[0030] The final concentration of the hexamethylenetetramine is 3-8 g / L, specifically 5 g / L;

[0031] The final concentration of the nickel chloride is 5-15 g / L, specifically 10 g / L;

[0032] The final concentration of sodium aminosulfonate is 1-3 g / L, specifically 2 g / L;

[0033] The final concentration of the sodium dodecylbenzenesulfonate is 1-3 g / L, specifically 2 g / L;

[0034] The final concentration of sodium tetraborate is 1-3 g / L, specifically 2 g / L.

[0035] The purpose of adding boric acid is to adjust the pH value of the plating solution, inhibit hydrogen evolution, and improve the quality and performance of the coating. Boric acid can also work synergistically with other components in the plating solution to enhance the stability of the solution and the electroplating effect. Therefore, maintaining an appropriate concentration of boric acid in the plating solution is crucial for obtaining high-quality electroless plating products.

[0036] Sodium tetraborate acts as a complexing agent and catalyst in the plating solution.

[0037] In step (4) of the above method, the neutral solution is an OP-10 aqueous solution, wherein the mass concentration of OP-10 in the OP-10 aqueous solution is 1%;

[0038] The phenolic compounds include, for example, 2,6-di-tert-butyl-p-methylphenol and / or phenolphthalein; the final concentration of the phenolic compounds is 1-1.5 g / L, specifically 1 g / L.

[0039] The present invention discovers that treatment with phenolic compounds can further enhance the electromagnetic shielding effect of the obtained fabrics or fibers, because phenolic compounds can absorb electromagnetic radiation, thereby reducing and enhancing the shielding effect of the fabrics or fibers.

[0040] The lightweight electromagnetic shielding multi-metal fabric prepared by the above method also falls within the protection scope of this invention.

[0041] The thickness of the lightweight electromagnetic shielding multi-metal fabric is 0.095±0.005mm, wherein the thickness of the metal layer is 3 micrometers.

[0042] The metal content is 29%±3% (based on a total fabric mass of 100), of which the silver content is 18%±2% and the balance is nickel;

[0043] The lightweight electromagnetic shielding multi-metal fabric has a basis weight of 65-68 g / m³. 2 ;

[0044] The resistance of the lightweight electromagnetic shielding multi-metal fabric is 130-190 milliohms / cm.

[0045] The present invention has the following advantages:

[0046] 1) The electromagnetic protection has a wide frequency band, and it can shield 99% of electromagnetic waves in the frequency range of 30MHz-40GHz;

[0047] 2) Strong protection effect: In the range of 30MHz-40GHz, the shielding effectiveness is 60.1-70dB, which can shield 99% of electromagnetic waves. Biological experiments have confirmed that it can play a very good protective role against damage caused by high-power microwaves.

[0048] 3) The nickel silver is firmly bonded to the fabric, has an A-grade wear resistance, and its shielding effectiveness decreases by less than 2% after 10 standard water washes;

[0049] 4) Uniform metal bonding: The thickness is 3 micrometers, and the thickness deviation in different areas is within 10%;

[0050] 5) Good wear resistance and oxidation resistance: Nickel is used, which has the characteristics of being wear-resistant and not easily oxidized. Phenolphthalein is also used for anti-oxidation treatment.

[0051] 6) It effectively combines the advantages of silver and nickel. Silver has the advantages of strong conductivity and good shielding effect, but its disadvantages are that it is not resistant to friction, is easy to oxidize, and its shielding effectiveness decays quickly with washing or time, and it is expensive. Nickel is resistant to friction, not easily oxidized, and does not decay easily. When wrapped around the outside of silver, it can provide good protection against silver friction, oxidation, and shielding decay. Nickel is also relatively inexpensive.

[0052] 7) Soft and lightweight fabric: Multi-functional metallic fabric with a weight of 65-68g / m² 2 It feels comfortable to the touch and is no different from ordinary fabric. Attached Figure Description

[0053] Figure 1 This is an electron microscope image of the lightweight electromagnetic shielding multi-metal fabric prepared in Example 1 of the present invention.

[0054] Figure 2 The graph shows the results of metal content determination of the lightweight multi-metal fabric prepared in Example 1 of this invention. Detailed Implementation

[0055] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0056] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0057] Example 1: Preparation of lightweight electromagnetic shielding multi-metal fabric

[0058] (1) Double-threaded nylon grey fabric (grey fabric weight 45g / m) 2After washing with OP-10 (1% mass concentration) aqueous solution at 25°C, 5.5g / L palladium sulfate + 2g / L sodium pyrophosphate were added to a 10% hexamethylenetetramine solution and heated to 70°C. The fabric was then immersed in the solution for 30 minutes to form a metal carrier on the surface of each fiber bundle.

[0059] (2) The fabric with the metal carrier on the surface is cleaned with hydrogen peroxide with a mass concentration of 38%, and then cleaned in potassium chloride solution with a mass concentration of 10% for 10 minutes. A silver ammonia solution is formed by 25L pure water + 20g of silver nitrate and silver cyanide mixture (silver cyanide weight ratio of 3%) + 0.03L ammonia water. The fabric is immersed in the silver ammonia solution, and a mixture of formaldehyde (diluted solution, mass concentration of 36%) 4% and EDTA (4%) is added. The fabric is soaked at 60℃ for 30 minutes to allow silver ions to form a metallic silver layer on the fabric surface under catalysis. The thickness of the metal layer is determined by detecting the resistivity of the fabric. The reaction is terminated when the resistivity of the fabric reaches 45Ω•cm. The fabric is then cleaned in sodium hydroxide and sodium hypophosphite solution (where the mass concentration of sodium hydroxide is 5% and the mass concentration of sodium hypophosphite is 2%).

[0060] The preparation method of silver ammonia solution includes adding sodium hydroxide aqueous solution to silver nitrate solution with a mass concentration of 5% containing silver cyanide to obtain a precipitate, and then adding ammonia water dropwise while shaking until the precipitate just dissolves to obtain silver ammonia solution;

[0061] (3) The fabric treated in step (2) is washed with 1% OP-10 aqueous solution to remove oil, and then washed with deionized water. The washed fabric is added to 55g / L nickel sulfate aqueous solution, 3g / L boric acid and 5g / L hexamethylenetetramine are added to form nickel boride, 10g / L nickel chloride, 2g / L sodium aminosulfonate, 2g / L sodium dodecylbenzenesulfonate and 2g / L sodium tetraborate are added, and the temperature is raised to 85°. Under the action of palladium catalysis, a chemical plating reaction occurs. The nickel in the solution is reduced and deposited on the catalytically active fabric and fully combined with the metallic silver to obtain the metallized silver nickel fiber fabric.

[0062] (4) Soak the obtained metallized silver-nickel fiber fabric in a 1% OP-10 aqueous solution; then add 1 g / L phenolphthalein solution (to form an antioxidant film on the metal surface); finally clean the fiber fabric with cleaning solution and dry it.

[0063] The resulting multi-metal fabric has a thickness of 0.095±0.005 mm; a metal content of 29%±3%, of which silver content is 18%±2% and nickel is the balance; and a weight of 67 g / m². 2 Multi-functional metal fabric thickness: 3 micrometers; resistance 160 milliohms / cm.

[0064] Figure 1Electron micrograph of the lightweight electromagnetic shielding multi-metal fabric.

[0065] Figure 2 The figure shows the results of the metal content determination of the lightweight electromagnetic shielding multi-metal fabric.

[0066] Example 2: Shielding effectiveness test of multi-metal fabric

[0067] I. Materials and Methods

[0068] (1) Main instruments and equipment

[0069] Analog signal generator 9kHz-20GHz, power level: (-120-10) dBm

[0070] Field strength meter 100kHz-18GHz, field strength: (0.8V / m-1000V / m)

[0071] Horn antenna 1GHz -18GHz

[0072] (2) Test according to specifications

[0073] The operation shall be carried out in accordance with the technical specifications stipulated in the national standards GB / T 23463-2009 "Protective Clothing - Microwave Radiation Protective Clothing" and GB / T 33615-2017 "Test Method for Electromagnetic Shielding Effectiveness of Clothing".

[0074] (3) Testing unit: Institute 203, Second Academy of China Aerospace Science and Industry Corporation.

[0075] II. Shielding effectiveness results

[0076] The electromagnetic radiation (1MHz~40GHz) shielding effectiveness (SE) of the above-mentioned fabric (prepared in Example 1) was tested, and the test results are shown in Table 1.

[0077] Table 1. Test results of shielding effectiveness of lightweight electromagnetic shielding multi-metal fabric.

[0078]

[0079] As shown in Table 1, within the frequency range of 30MHz to 40GHz, the maximum shielding performance of this protective material is 79dB (18000MHz), and the minimum shielding performance is 60.1dB (100 MHz). Within the frequency range of 30MHz to 40GHz, it can shield more than 99.99% of electromagnetic waves.

[0080] Table 2. Shielding effectiveness test results of lightweight electromagnetic shielding multi-metal fabric after 10 washes.

[0081]

[0082] As shown in Table 2, after ten water washes according to national standards, the maximum shielding performance of the protective material is 78.3dB (18000MHz) and the minimum shielding performance is 60.1dB (80MHz) in the frequency range of 30MHz~40GHz, with the shielding effectiveness attenuation within 2%.

[0083] Example 3: Garmentability Testing of Multi-Metal Fabrics

[0084] Testing Unit: National Ecological and Functional Textiles and Apparel Quality Inspection and Testing Center

[0085] The operation shall be carried out in accordance with the technical specifications stipulated in the national standards GB / T 23463-2009 "Protective Clothing - Microwave Radiation Protective Clothing" and GB 18401-2010 "National Basic Safety Technical Specifications for Textile Products".

[0086] Formaldehyde content: Not detected; pH value: 6.2; Tensile strength: warp 460N, weft 400N; Tear strength: warp 41N, weft ≥36N; Abrasion resistance: Grade A; Dimensional change after washing: warp +0.3, weft +0.1; Dimensional change after ten washes: warp +0.3, weft 0; Air permeability: 144.36mm / s; Moisture permeability: 9.64×10 3 g / (m 2 24h); Abrasion resistance grade A, salt resistance (24h) with no corrosion.

[0087] According to GB 18401-2010 "National Basic Safety Technical Specifications for Textile Products" and GB / T 23463-2009 "Protective Clothing - Microwave Radiation Protective Clothing", the formaldehyde content is <75mg / kg, pH value is 4.0~7.5, tensile strength is ≥450N in warp and ≥400N in weft, tear strength is ≥40N in warp and ≥30N in weft, air permeability is ≥60mm / s, moisture permeability is ≥6000g / (m2·d), and dimensional change rate after washing is 2.0%~-2.0% in warp and 2.0%~-2.0% in weft. The performance parameters of the lightweight electromagnetic shielding multi-metal fabric of this invention all comply with the requirements of GB 18401-2010 "National Basic Safety Technical Specifications for Textile Products" and GB / T 23463-2009 "Protective Clothing - Microwave Radiation Protective Clothing".

[0088] Example 4: Garmentability Testing of Multi-Metal Fabrics

[0089] Fifty male Wistar rats (grade 2, weighing 300 ± 20 g, provided by Vital River Laboratory Animal Technology Co., Ltd.) were randomly divided into three groups: a normal control group, a radiation control group, and a protective group, with 25 rats in each group. A high-power C-band microwave radiation source with an average power density of 30 mW / cm² was used. 2 The radiation time was 30 minutes. The control group was placed in an acrylic box and subjected to sham radiation, i.e., the radiation source was turned off, while other conditions remained the same.

[0090] 1. Testing of learning and memory abilities in rats

[0091] A water maze testing system (purchased from Xuzhou Bona Information Technology Co., Ltd., SA201) was used to test the learning and memory abilities of rats. The system mainly consists of a temperature-controlled water maze pool, a camera, and trajectory tracking and analysis software. The pool's inner walls were dark, with a diameter of 150 cm and a height of 50 cm, surrounded by a dark cloth curtain. During the experiment, the water depth was 20 cm, and the room temperature was controlled at approximately 22 degrees Celsius. The pool was divided into four sections, designated as quadrants one, two, three, and four, with the rat's placement point in the center of each quadrant's wall. A dark platform with a diameter of 10 cm and a height of 18 cm was placed in the central area of ​​quadrant one. The camera was mounted above the pool and connected to a computer to track and collect data on the rats' swimming trajectories.

[0092] Two days before radiation exposure, ten rats were trained in each group. The rats were placed in the first quadrant of the pool, horizontally facing the pool wall, and allowed to swim freely. If they found a platform within 60 seconds, they were allowed to stay on it for 15 seconds; otherwise, they were guided to the platform and allowed to stay there for 15 seconds. This process was repeated starting from the next quadrant until all four quadrants were completed. The rats were dried and returned to their cages. After two days of training, the time taken for a rat to find a platform within 60 seconds was recorded (60 seconds was considered the time if it failed to find the platform). The average time across the four quadrants was used as the average escape latency. Five rats with significantly different values ​​were removed from each group, leaving ten rats for subsequent experimental testing. The rats were then placed in the first quadrant of the pool, horizontally facing the pool wall, and allowed to swim freely in search of a platform. Record the time taken for the rat to find the platform within 60 seconds. Once found, immediately remove the rat and place it in the next quadrant until all four quadrants are reached. If the rat fails to find the platform within 60 seconds, this time is recorded as 60 seconds. Statistically analyze the average escape latency of each group of rats.

[0093] Compared with the control group, the mean escape latency of rats in the radiation group was significantly prolonged at all time points after radiation (p<0.01 or p<0.05) at 1, 3, and 7 days (see Table 2), indicating that microwave radiation impaired the spatial learning and memory ability of rats. Compared with the radiation group, the mean escape latency of the protective group was significantly shorter, with a significant difference at 2-4 days after radiation (p<0.05). This indicates that the spatial learning and memory ability of rats in the protective group was significantly stronger than that in the radiation group, meaning that the fabric of this invention can protect the spatial learning and memory ability of rats. The results are shown in Table 3.

[0094] Table 3. Effects of fabric on the mean escape latency of rats after high-power microwave radiation.

[0095]

[0096] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, #p<0.05.

[0097] 2. Detection of electroencephalographic activity in rats

[0098] Electroencephalograms (EEGs) of rats in each group were collected and detected after microwave radiation. Five rats were selected from each group, weighed, and anesthetized by intraperitoneal injection of 1% sodium pentobarbital solution at a dose of 5 ml / kg body weight. When the rats were in a state of mild anesthesia, their EEG activity was collected using a Biopac MP-150 multichannel physiological recorder. The specific procedure was as follows: after shaving the rat's head with a hair clipper, needle electrodes were inserted subcutaneously at 1 cm to the left and right of the center of the top of the head (avoiding blood vessels). A reference electrode was inserted into the left earlobe. EEG fluctuations were observed, and recording was performed continuously for 5 minutes after the EEG stabilized. The changes in EEG were analyzed after the data collection. In the radiation group, the β wave decreased and the θ and δ waves increased after radiation (p<0.05); while in the protection group, the β wave increased and the θ and δ waves decreased (p<0.05). The results are shown in Table 4.

[0099] Table 4. Effects of fabric on electroencephalogram (EEG) of rats 1 day after high-power microwave radiation.

[0100]

[0101] Note: Compared with the control group, *p<0.05; compared with the radiation group, # p<0.05.

[0102] 3. Detection of electrocardiographic activity in rats

[0103] Electrocardiograms (ECGs) of rats in each group were collected and detected after microwave radiation. Five rats were selected from each group, weighed, and anesthetized by intraperitoneal injection of 1% sodium pentobarbital solution at a dose of 5 ml / kg body weight. When the rats were in a state of mild anesthesia, their ECG activity was collected using a Biopac MP-150 multichannel physiological recorder. Changes in ECG were analyzed after collection. In the radiation group, the ECG values ​​of µV, R (µV), and T (µV) decreased after radiation (p<0.01), while the heart rate increased (p<0.01). In contrast, the ECG values ​​of µV, R (µV), and T (µV) increased (p<0.01 or p<0.05), while the heart rate decreased (p<0.01). The results are shown in Table 5.

[0104] Table 5. Effects of fabric on electrocardiogram of rats 1 day after high-power microwave radiation.

[0105]

[0106] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, #p<0.05.

[0107] 4. Rat sperm motility test

[0108] Rats in each group were anesthetized 1 day and 14 days after radiation exposure. The epididymal duct was dissected and rinsed with 0.3-0.5 ml of physiological saline (incubated at 37°C for 20 minutes) to prepare a sperm suspension. 10 μL of the sperm suspension was pipetted onto a glass slide, and eight fields of view were randomly selected under an inverted microscope. Sperm motility was analyzed using the SCA sperm dynamics analysis system (Spain, SCA). On days 1 and 14 after radiation exposure, sperm motility in the radiation group was lower than that in the normal control group (p<0.01); while sperm motility in the protection group was higher than that in the radiation group (p<0.01 or p<0.05). The results are shown in Table 6.

[0109] Table 6. Effects of fabric on sperm motility (%) in rats after high-power microwave radiation.

[0110]

[0111] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, # p<0.05, ## p<0.01.

[0112] 5. Effects on the immune function of rats

[0113] Rats in each group were anesthetized after radiation exposure, and blood was drawn from the abdominal aorta. CD4 and CD8 levels were detected by flow cytometry. In the radiation group, the immune function indicators CD4 and CD4 / CD8 were lower than those in the normal control group (p<0.05), while CD8 was higher (p<0.01). In contrast, in the protection group, the immune function indicators CD4 and CD4 / CD8 were higher (p<0.01 or p<0.05) than those in the radiation group, while CD8 was lower (p<0.05). The results are shown in Table 7.

[0114] Table 7. Effects of fabric on immune function in rats one day after high-power microwave radiation.

[0115]

[0116] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, # p<0.05, ## p<0.01

[0117] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for preparing lightweight electromagnetic shielding multi-metal fabric, comprising the following steps: (1) Add palladium sulfate and sodium pyrophosphate to a hexamethylenetetramine solution, mix, and immerse the greige fabric after OP-10 cleaning in the resulting solution to form a metal carrier on the surface of each fiber bundle. (2) Prepare a silver ammonia solution using pure water, a mixture of silver nitrate and silver cyanide, and ammonia. Immerse the fabric with the metal carrier formed on its surface in the silver ammonia solution, add formaldehyde dilution and EDTA mixture, and soak it to allow silver ions to form a metallic silver layer on the fabric surface under catalysis. When the resistivity of the fabric reaches 30-50 Ω•cm, remove the fabric to terminate the reaction. Then wash the fabric in a sodium hydroxide and sodium hypophosphite solution. (3) The fabric treated in step (2) is cleaned with OP-10 aqueous solution to remove oil, and then cleaned with deionized water. The cleaned fabric is added to nickel sulfate aqueous solution, boric acid and hexamethylenetetramine are added, and the reaction is carried out. Nickel chloride, sodium aminosulfonate, sodium dodecylbenzenesulfonate and sodium tetraborate are added, and the temperature is raised to 80-90°. Under the action of palladium catalysis, a chemical plating reaction occurs. The nickel in the solution is reduced and deposited on the catalytically active fabric and fully combines with the metallic silver to obtain metallized silver nickel fiber fabric. (4) Immerse the obtained metallized silver-nickel fiber fabric in a neutral solution, add phenolphthalein solution to the neutral solution, soak for 20-40 minutes, and finally clean the fiber fabric with cleaning solution and dry it.

2. The method according to claim 1, characterized in that, In step (1), the fabric is cleaned with an OP-10 aqueous solution at 25-35℃, wherein the mass concentration of OP-10 in the OP-10 aqueous solution is 1%. The fabric is a double-threaded nylon fabric; the fabric weight is 45g / m². 2 ; The concentration of palladium sulfate in the resulting solution is 5-6 g / L; The concentration of sodium pyrophosphate is 0.5-5 g / L; The mass concentration of hexamethylenetetramine in the hexamethylenetetramine solution is 5-15%; The soaking temperature is 50-80℃ and the soaking time is 20-60 minutes.

3. The method according to claim 1 or 2, characterized in that, The ratio of pure water, a mixture of silver nitrate and silver cyanide, and ammonia is as follows: 20-30 L : 18-22 g : 0.024-0.036 L; In the mixture of silver nitrate and silver cyanide, the weight percentage of silver cyanide is 1-5%; The mass concentration of the formaldehyde dilution is 36%. Based on the mass of 1 L of silver ammonia solution, the amount of formaldehyde diluent added is 4%, and the amount of EDTA added is 4-6%. The soaking time is 20-40 minutes, and the soaking temperature is 60℃.

4. The method according to claim 1 or 2, characterized in that, In step (3), the concentration of nickel sulfate in the nickel sulfate aqueous solution is 50-60 g / L; The final concentration of the boric acid is 2-5 g / L; The final concentration of the hexamethylenetetramine is 3-8 g / L; The final concentration of the nickel chloride is 5-15 g / L; The final concentration of the sodium aminosulfonate is 1-3 g / L; The final concentration of the sodium dodecylbenzenesulfonate is 1-3 g / L; The final concentration of the sodium tetraborate is 1-3 g / L.

5. The method according to claim 1 or 2, characterized in that, In step (4), the neutral solution is an aqueous solution of OP-10, wherein the mass concentration of OP-10 in the aqueous solution of OP-10 is 1%; and the final concentration of phenolphthalein is 1-1.5 g / L.

6. A lightweight electromagnetic shielding multi-metal fabric prepared by any one of claims 1-5.

7. The lightweight electromagnetic shielding multi-metal fabric according to claim 6, characterized in that, The thickness of the lightweight electromagnetic shielding multi-metal fabric is 0.095±0.005mm, wherein the thickness of the metal layer is 3 micrometers. The metal content is 29%±3%, of which silver content is 18%±2% and nickel content is the balance; The lightweight electromagnetic shielding multi-metal fabric has a basis weight of 65-68 g / m³. 2 .

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