Lightweight electromagnetic shielding multi-metal fabric and preparation method thereof

Abstract

The invention provides a lightweight electromagnetic shielding multi-metal fabric and a preparation method thereof. The prepared fabric is wide in electromagnetic protection frequency band and high in protection effect, nickel silver and gray fabric are firmly combined, good wear resistance and oxidation resistance are achieved, the advantages of silver and nickel are powerfully combined, silver has the advantages of being high in conductivity and good in shielding effect, and silver has the defects of being not resistant to friction, prone to oxidation, rapid in shielding effectiveness attenuation along with washing or time and high in cost; nickel is resistant to friction, not prone to oxidation and not prone to attenuation, wraps the silver, can play a good role in protecting the silver from friction, oxidation, attenuation shielding and the like, and is low in cost; the prepared diversified metal cloth has the gram weight of 65-68 g / m < 2 > and comfortable hand feeling, and is not different from common cloth.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic radiation protection materials and electromagnetic radiation damage protection, and specifically relates to a lightweight electromagnetic shielding multi-element metal fabric and a preparation method thereof. Background Art

[0002] Studies have shown that a certain dose of electromagnetic radiation can cause significant damage to humans and animals, and can cause multiple systemic damage changes, mainly in the central nervous system and reproductive system. 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 activity rate and vitality of rat epididymal sperm.

[0003] Among the many electromagnetic protection measures, wearing electromagnetic protective clothing is the most direct and effective protective measure for individual protection, and the research on protective materials is the basic guarantee of protective clothing. At present, although there are many types of electromagnetic protective materials and protective clothing, the quality varies greatly, the protective effect needs to be improved, and there is a lack of it. Most of the radiation protection clothing on the market is for civilian use, and the audience is mainly pregnant women. Although it has a certain degree of protective effect, there are higher requirements for special occupational groups or military protective clothing, and there is still a need for protective clothing with high strength, wide coverage frequency, light and soft, high water resistance and low shielding efficiency attenuation. Therefore, fabrics with the function of shielding electromagnetic radiation need to be further improved. Summary of the invention

[0004] The object of the present invention is to provide a lightweight electromagnetic shielding multi-element metal fabric and a preparation method thereof.

[0005] The lightweight electromagnetic shielding multi-element metal fabric provided by the present invention is prepared by a method comprising the following steps: (1) Add palladium sulfate and sodium pyrophosphate to a hexamethylenetetramine solution, mix them, and soak the grey cloth washed with OP-10 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 water. Immerse the resulting cloth with a metal carrier formed on the surface in the silver ammonia solution. Add a mixture of formaldehyde dilution and EDTA and soak the cloth so that silver ions form a metallic silver layer on the surface of the cloth under catalysis. When the resistivity of the cloth reaches 30-50Ω•cm, remove the cloth to terminate the reaction. Then wash the cloth in a sodium hydroxide and sodium hypophosphite solution. (3) The fabric treated in step (2) is washed with an OP-10 aqueous solution to remove oil, and then washed with deionized water, the washed fabric is added to a nickel sulfate aqueous solution, boric acid and hexamethylenetetramine are added, reacted, nickel chloride, sodium aminosulfonate, sodium dodecylbenzenesulfonate and sodium tetraborate are added, the temperature is raised to 80-90°, and a chemical plating reaction occurs under the catalytic action of palladium, the nickel in the solution is reduced and deposited on the fabric with catalytic activity and fully combined with metallic silver, thereby obtaining a metallized silver-nickel fiber fabric; (4) Immerse the obtained metallized silver-nickel fiber fabric in a neutral solution, add a phenolphthalein solution into the neutral solution, soak for 20-40 minutes, and finally wash the fiber fabric with a cleaning solution and dry it.

[0006] In step (1) of the above method, the grey cloth is washed 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%; The grey fabric can be double-line nylon grey fabric; the weight of the grey fabric is 45g / m 2 ; In the obtained solution, the concentration of palladium sulfate may be 5-6 g / L, specifically 5.5 g / L; The concentration of sodium pyrophosphate may be 0.5-5 g / L, specifically 2 g / L; The mass concentration of hexamethylenetetramine in the hexamethylenetetramine solution is 5-15%, specifically 10%; The soaking temperature may be 50-80°C, specifically 70°C, and the soaking time may be 20-60min, specifically 30min.

[0007] In step (2) of the above method, before the cloth with the metal carrier formed on the surface is immersed in the silver ammonia solution, it also includes the operation of washing it with hydrogen peroxide solution and potassium chloride solution in sequence; Wherein, the mass concentration of the hydrogen peroxide solution is 27-40%, specifically 38%; The mass concentration of the potassium chloride solution may be 5%-15%; The proportions of pure water, a mixture of silver nitrate and silver cyanide, and ammonia water may be: 20-30 L: 18-22 g: 0.024-0.036 L, specifically 25 L: 20 g: 0.03 L; In the mixture of silver nitrate and silver cyanide, the weight proportion of silver cyanide is 1-5%, specifically 3%; The mass concentration of the formaldehyde dilution is 36%; Based on the mass of 1 L of silver ammonia solution, the amount of formaldehyde dilution added is 4%, and the amount of EDTA added is 4-6%; The soaking time may be 20-40 minutes, specifically 30 minutes; The preparation method of the silver ammonia solution is as follows: adding a sodium hydroxide aqueous solution to a silver nitrate solution containing silver cyanide of a certain concentration to obtain a precipitate, and then adding ammonia water dropwise while shaking until the precipitate is just dissolved to obtain a silver ammonia solution; wherein the mass concentration of silver nitrate in the silver nitrate solution is generally 5%; The invention adopts silver nitrate containing a small amount of silver cyanide as a raw material, aiming to slow down the speed of silver deposition and obtain a uniform silver layer.

[0008] The temperature during the silver ammonia solution treatment in the present invention (referring to the immersion temperature in step (2)) is generally 60°C.

[0009] 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%.

[0010] In step (3), the concentration of nickel sulfate in the nickel sulfate aqueous solution is 50-60 g / L, specifically 55 g / L; The final concentration of the boric acid is 2-5 g / L (mass concentration), specifically 3 g / L; The final concentration of the hexamethylenetetramine is 3-8 g / L, specifically 5 g / L; The final concentration of nickel chloride is 5-15 g / L, specifically 10 g / L; The final concentration of the sodium sulfamate is 1-3 g / L, specifically 2 g / L; The final concentration of the sodium dodecylbenzene sulfonate is 1-3 g / L, specifically 2 g / L; The final concentration of the sodium tetraborate is 1-3 g / L, specifically 2 g / L.

[0011] The purpose of adding boric acid is to adjust the pH value of the plating solution, inhibit the precipitation of hydrogen, 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 plating solution and the electroplating effect. Therefore, maintaining an appropriate concentration of boric acid in the plating solution is crucial to obtaining high-quality chemical plating products.

[0012] In the plating solution, sodium tetraborate is a complexing agent and catalyst.

[0013] 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%; The phenolic compound includes, for example, 2,6-di-tert-butyl-p-methylphenol and / or phenolphthalein; the final concentration of the phenolic compound is 1-1.5 g / L, specifically 1 g / L.

[0014] The present invention has found that the electromagnetic shielding effect of the resulting fabric or fiber can be further enhanced by treating with phenolic compounds, because the phenolic compounds can absorb electromagnetic radiation, thereby reducing and enhancing the shielding effect of the fabric or fiber. The lightweight electromagnetic shielding multi-element metal fabric produced by the above method also falls within the protection scope of the present invention.

[0015] The thickness of the lightweight electromagnetic shielding multi-element metal fabric is 0.095±0.005 mm, wherein the thickness of the metal layer is 3 microns; The metal content is 29% ± 3% (based on the total mass of the fabric as 100), of which the silver content is 18% ± 2% and the balance is nickel; The gram weight of the lightweight electromagnetic shielding multi-element metal fabric is 65-68 g / m 2 ; The electrical resistance in the lightweight electromagnetic shielding multi-element metal fabric is 130-190 milliohms / cm.

[0016] The present invention has the following advantages: 1) The frequency band of electromagnetic protection is wide, and 99% of electromagnetic waves can be shielded in the frequency range of 30MHz-40GHz; 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 good protective role against damage caused by high-power microwaves; 3) Nickel silver and grey cloth are firmly bonded, with grade A wear resistance. After 10 standard washings, the shielding effectiveness decays within 2%; 4) Uniform metal bonding: thickness is 3 microns, and the thickness deviation in different areas is within 10%; 5) Good wear resistance and oxidation resistance: Nickel is used, which is resistant to friction and not easy to oxidize. Phenolphthalein is used for antioxidant treatment. 6) It effectively combines the advantages of silver and nickel. The advantages of silver are strong conductivity and good shielding effect, but the disadvantages are that it is not resistant to friction, easy to oxidize, and the shielding effectiveness decays quickly with washing or time, and the cost is high. Nickel is resistant to friction, not easy to oxidize, and not easy to decay. Wrapped on the outside of silver, it can play a good role in protecting silver from friction, oxidation, shielding attenuation, etc. The cost of nickel is relatively low; 7) Soft fabric: diversified metal fabric weight 65-68g / m 2 , feels comfortable and is no different from ordinary fabrics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an electron microscope image of the lightweight electromagnetic shielding multi-element metal fabric prepared in Example 1 of the present invention.

[0018] Figure 2 This is a graph showing the metal content measurement results of the lightweight multi-element metal fabric prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0020] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0021] Example 1 Preparation of lightweight electromagnetic shielding multi-element metal fabric (1) Double-line nylon grey fabric (grey fabric weight 45g / m 2 ) After washing with 25°C OP-10 (mass concentration 1%) aqueous solution, 5.5g / L palladium sulfate + 2g / L sodium pyrophosphate were added to 10% hexamethylenetetramine solution heated to 70 degrees, and the fabric was immersed in the solution for 30 minutes to form a metal carrier on the surface of each fiber bundle; (2) The fabric with metal carriers formed on the surface is cleaned with 38% hydrogen peroxide, then cleaned in 10% potassium chloride solution for 10 minutes, and a silver-ammonia solution is formed with 25L pure water + 20g silver nitrate and silver cyanide mixture (the weight proportion of silver cyanide is 3%) + 0.03L ammonia water. The fabric is immersed in the silver-ammonia solution, and a mixture of 4% formaldehyde (diluent, mass concentration is 36%) and EDTA (4%) is added. The fabric is soaked at 60°C for 30 minutes to form a metallic silver layer on the fabric surface under the catalysis of silver ions. 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 a sodium hydroxide and sodium hypophosphite solution (the mass concentration of sodium hydroxide is 5% and the mass concentration of sodium hypophosphite is 2%). The preparation method of the silver ammonia solution comprises adding a sodium hydroxide aqueous solution to a silver nitrate solution containing silver cyanide with a mass concentration of 5% to obtain a precipitate, and then adding ammonia water dropwise while shaking until the precipitate is just dissolved to obtain the silver ammonia solution; (3) The fabric treated in step (2) is washed and degreased with a 1% OP-10 aqueous solution, and then washed with deionized water. The washed fabric is added to a 55 g / L nickel sulfate aqueous solution, 3 g / L boric acid and 5 g / L hexamethylenetetramine are added to form nickel boride, 10 g / L nickel chloride, 2 g / L sodium aminosulfonate, 2 g / L sodium dodecylbenzenesulfonate and 2 g / L sodium tetraborate are added, the temperature is raised to 85°, and a chemical plating reaction occurs under the catalytic action of palladium. The nickel in the solution is reduced and deposited on the fabric with catalytic activity to fully combine with the metallic silver to obtain a metallized silver-nickel fiber fabric; (4) Soaking the obtained metallized silver-nickel fiber fabric in a 1% by mass concentration OP-10 aqueous solution; then adding 1 g / L phenolphthalein solution (to form an antioxidant film on the metal surface); finally, washing the fiber fabric with a cleaning solution and drying it.

[0022] The thickness of the obtained multi-metal fabric is 0.095±0.005 mm; the metal content is 29%±3%, of which the silver content is 18%±2% and the balance is nickel. The weight of the multi-metal fabric is 67g / m 2 , diversified metal fabric thickness: 3 microns; resistance 160 milliohms / cm.

[0023] Figure 1 This is an electron microscope image of the lightweight electromagnetic shielding multi-element metal fabric produced.

[0024] Figure 2 This is a graph showing the metal content measurement results of the lightweight electromagnetic shielding multi-element metal fabric.

[0025] Example 2 Shielding effectiveness test of multi-element metal fabric 1. Materials and Methods (1) Main instruments and equipment Analog signal generator 9kHz-20GHz, power level: (-120-10)dBm Field strength meter 100kHz-18GHz, field strength: (0.8V / m-1000V / m) Horn Antenna 1GHz -18GHz (2) Test based on specifications The operation is carried out in accordance with the technical specifications specified in the national standards GB / T 23463-2009 "Protective clothing - Microwave radiation protection clothing" and GB / T 33615-2017 "Test method for electromagnetic shielding effectiveness of clothing".

[0026] (3) Testing unit: Institute 203 of the Second Academy of China Aerospace Science and Industry Corporation.

[0027] 2. Shielding effectiveness results The electromagnetic radiation (1 MHz to 40 GHz) shielding effectiveness (SE) test was performed on the fabric (prepared in Example 1). The test results are shown in Table 1.

[0028] Table 1 Shielding effectiveness test results of lightweight electromagnetic shielding multi-element metal fabrics

[0029] It can be seen from Table 1 that within the frequency range of 30MHz~40GHz, the maximum shielding performance of the protective material is 79dB (18000MHz), and the minimum shielding performance is 60.1dB (100 MHz). Within the frequency range of 30MHz~40GHz, it can shield more than 99.99% of electromagnetic waves.

[0030] Table 2 Shielding effectiveness test results of lightweight electromagnetic shielding multi-element metal fabrics after washing 10 times

[0031] It can be seen from Table 2 that after ten water washings according to the national standard, in the frequency range of 30MHz~40GHz, the maximum shielding performance of the protective material is 78.3dB (18000MHz), the minimum shielding performance is 60.1dB (80MHz), and the shielding effectiveness attenuation is within 2%.

[0032] Example 3: Test of garment-quality indexes of multi-element metal fabrics Testing unit: National Ecological and Functional Textiles and Clothing Quality Inspection and Testing Center The operation is carried out in accordance with the technical specifications stipulated in the national standards GB / T 23463-2009 "Protective clothing - Microwave radiation protection clothing" and GB 18401-2010 "National basic safety technical specifications for textile products".

[0033] Formaldehyde content: not detected; pH value: 6.2; Breaking strength: 460N in warp, 400N in weft; Tear strength: 41N in warp, ≥36N in weft: Friction resistance grade A; Dimensional change rate after washing: +0.3 in warp, +0.1 in weft; Dimensional change rate after ten washings: +0.3 in warp, 0 in weft; Air permeability: 144.36mm / s, Moisture permeability: 9.64×10 3 g / (m 2 .24h); wear resistance grade A, salt resistance (24h) no corrosion.

[0034] 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, breaking strength: warp ≥450N, weft ≥400N, tearing strength: warp ≥40N, weft ≥30N, air permeability: ≥60mm / s, moisture permeability: ≥6000g / (m2·d), washing size change rate: warp 2.0%~-2.0%, weft 2.0%~-2.0%. The performance parameter tests of the lightweight electromagnetic shielding multi-element metal fabric of the present invention are all in accordance with the provisions of GB 18401-2010 "National Basic Safety Technical Specifications for Textile Products" and GB / T23463-2009 "Protective Clothing Microwave Radiation Protective Clothing".

[0035] Example 4: Test of garment-quality indexes of multi-metal fabrics Fifty second-grade Wistar male rats weighing 300±20 g (provided by Weitong Lihua Experimental Animal Technology Co., Ltd.) were randomly divided into three groups: normal control group, radiation control group and protection group, with 25 rats in each group. C-band high-power microwave radiation source with an average power density of 30 mW / cm 2 The control group was placed in a plexiglass box and then sham-irradiated, i.e. the radiation source was turned off, while other conditions were the same as before.

[0036] 1. Detection of rat learning and memory ability The learning and memory ability of rats was tested using a water maze test system (purchased from Xuzhou Bona Information Technology Co., Ltd., SA201). The system mainly consists of a temperature-controlled water maze pool, a camera, and trajectory tracking and analysis software. The inner wall of the pool is dark, with a diameter of 150 cm and a height of 50 cm, and is surrounded by dark curtains; during the experiment, the water was injected to a depth of 20 cm, and the room temperature was controlled at around 22 degrees Celsius. The pool was divided into four parts, which were respectively designated as the first, second, third, and fourth quadrants. The middle of the pool wall in each quadrant was the point where the rat was placed. A dark platform with a diameter of 10 cm and a height of 18 cm was placed in the central area of ​​the first quadrant. The camera was mounted above the pool and connected to a computer to track and collect the swimming trajectory of the rat.

[0037] Each group of rats underwent adaptive training 2 days before radiation, with 10 rats in each group. The rats were placed in the first quadrant with the liquid level facing the pool wall and allowed to swim freely in the pool. If the platform is found within 60 seconds, it is allowed to stay on the platform for 15 seconds; if it is not found, it is guided to the platform and stay for 15 seconds. Then this operation is repeated from the next quadrant until 4 quadrants are completed. The rats were wiped dry and returned to the cage. After 2 days of training, the time taken by the rats to find the platform within 60 seconds was counted. If it was not found, it was recorded as 60 seconds; the mean of the time in the 4 quadrants was used as an observation index, which was the average escape latency. Five rats with large numerical deviations were eliminated from each group, and 10 rats were retained for subsequent experimental testing. The rats were placed in the first quadrant with the liquid level facing the pool wall and allowed to swim freely in the pool to find the platform. The time it takes to find the platform within 60 seconds was recorded. After finding the platform, the rat was immediately taken out and put into the next quadrant to complete the task. If the rat still failed to find the platform within 60 seconds, it was recorded as 60 seconds. The average escape latency of each group of rats was statistically analyzed.

[0038] Compared with the control group, the average escape latency of the rats in the radiation group was significantly prolonged at each time point after radiation, 1 day, 3 days, and 7 days after radiation (p<0.01 or p<0.05) (see Table 2), indicating that microwave radiation damaged the spatial learning and memory ability of the rats. Compared with the radiation group, the average escape latency of the protection group was significantly shorter, and the difference was significant 2-4 days after radiation (p<0.05). It shows that the spatial learning and memory ability of the rats in the protection group is significantly stronger than that in the radiation group, that is, the fabric of the present invention can protect the spatial learning and memory ability of the rats. The results are shown in Table 3.

[0039] Table 3 Effect of fabrics on the average escape latency of rats after high-power microwave radiation

[0040] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, #p<0.05.

[0041] 2. Detection of rat brain electrical activity After microwave radiation, the EEG of rats in each group was collected and tested. Five rats were selected from each group. After weighing, 1% sodium pentobarbital solution was injected intraperitoneally at a dose of 5 ml per kg of body weight for anesthesia. When the rats were in a state of light anesthesia, the MP-150 multi-channel physiological recorder of Biopac was used to collect the EEG activity of the rats. The specific operation was as follows: after preparing the skin of the rat's head with a hair clipper, the needle electrode was inserted into the subcutaneous part 1 cm to the left and right of the middle of the top of the head (be careful to avoid blood vessels), and the reference electrode was inserted into the left earlobe to observe the EEG fluctuations. After stabilization, continuous recording was performed for 5 minutes. After the collection was completed, the changes in EEG were analyzed. The EEG β wave of the irradiated group rats decreased after radiation, and the θ and δ waves increased after radiation (p<0.05); while the EEG β wave of the protection group increased, and the θ and δ waves decreased (p<0.05). The results are shown in Table 4.

[0042] Table 4 Effects of fabrics on EEG of rats after 1 day of high-power microwave radiation

[0043] Note: Compared with the control group, *p<0.05; compared with the radiation group, # p<0.05.

[0044] 3. Detection of cardiac electrical activity in rats After microwave radiation, the ECG of rats in each group was collected and tested. Five rats were selected from each group. After weighing, 1% sodium pentobarbital solution was injected intraperitoneally at a dose of 5 ml per kg of body weight for anesthesia. When the rats were in a lightly anesthetized state, the MP-150 multi-channel physiological recorder of Biopac was used to collect the ECG activity of the rats. After the collection was completed, the changes in ECG were analyzed. The ECG µV, R (µv), and T (µV) of the rats in the radiation group decreased after radiation (p<0.01), and the heart rate increased after radiation (p<0.01); while the ECG µV, R (µv), and T (µV) of the rats in the protection group increased (p<0.01 or p<0.05), and the heart rate decreased (p<0.01). The results are shown in Table 5.

[0045] Table 5 Effects of fabrics on ECG of rats after high-power microwave radiation for 1 day

[0046] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, #p<0.05.

[0047] 4. Rat sperm motility test The rats in each group were anesthetized 1 day and 14 days after radiation, and the epididymal duct was cut open with dissecting scissors, rinsed with 0.3-0.5 ml of normal saline (incubated at a constant temperature of 37 degrees Celsius for 20 minutes), and sperm suspension was prepared. 10 microliters of sperm suspension was aspirated with a pipette and placed below the slide. Eight fields of view were randomly selected under an inverted microscope, and sperm motility was analyzed using the SCA sperm dynamic analysis system (Spain, SCA). The sperm motility of rats in the radiation group was lower than that of the normal control group on the 1st and 14th day (p<0.01); while the sperm motility of rats 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.

[0048] Table 6 Effect of fabrics on sperm motility of rats after high-power microwave irradiation (%)

[0049] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, # p<0.05, ## p<0.01.

[0050] 5. Effects on the immune function of rats The rats in each group were anesthetized after radiation, and blood was drawn from the abdominal aorta. CD4 and CD8 were detected by flow cytometry. The immune function indexes CD4 and CD4 / CD8 of the rats in the radiation group were lower than those in the normal control group (p<0.05), and CD8 was higher than that in the normal control group (p<0.01); while the immune function indexes CD4 and CD4 / CD8 of the rats in the protection group were higher than those in the radiation group (p<0.01 or p<0.05), and CD8 was lower than that in the radiation group (p<0.05). The results are shown in Table 7.

[0051] Table 7 Effects of fabrics on immune function of rats after high-power microwave radiation for 1 day

[0052] Note: Compared with the control group, *p<0.05, **p<0.01; compared with the radiation group, # p<0.05, ## p<0.01 The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. A method for preparing a lightweight electromagnetic shielding multi-element metal fabric, comprising the following steps: (1) Add palladium sulfate and sodium pyrophosphate to a hexamethylenetetramine solution, mix them, and soak the grey cloth washed with OP-10 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 water. Immerse the resulting cloth with a metal carrier formed on the surface in the silver ammonia solution. Add a mixture of formaldehyde dilution and EDTA and soak the cloth so that silver ions form a metallic silver layer on the surface of the cloth under catalysis. When the resistivity of the cloth reaches 30-50Ω•cm, remove the cloth to terminate the reaction. Then wash the cloth in a sodium hydroxide and sodium hypophosphite solution. (3) The fabric treated in step (2) is washed with an OP-10 aqueous solution to remove oil, and then washed with deionized water, the washed fabric is added to a nickel sulfate aqueous solution, boric acid and hexamethylenetetramine are added, reacted, nickel chloride, sodium aminosulfonate, sodium dodecylbenzenesulfonate and sodium tetraborate are added, the temperature is raised to 80-90°, and a chemical plating reaction occurs under the catalytic action of palladium, the nickel in the solution is reduced and deposited on the fabric with catalytic activity and fully combined with metallic silver, thereby obtaining a metallized silver-nickel fiber fabric; (4) Immerse the obtained metallized silver-nickel fiber fabric in a neutral solution, add a phenolphthalein solution into the neutral solution, soak for 20-40 minutes, and finally wash the fiber fabric with a cleaning solution and dry it.

2. The method according to claim 1, characterized in that In step (1), the grey cloth is washed 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%; The grey fabric is double-line nylon grey fabric; the weight of the grey fabric is 45g / m 2 ; The concentration of palladium sulfate in the resulting solution is 5-6 g / L; The concentration of sodium pyrophosphate is 0.5-5g / L; The mass concentration of hexamethylenetetramine in the hexamethylenetetramine solution is 5-15%; The soaking temperature is 50-80°C and the soaking time is 20-60min.

3. The method according to claim 1 or 2, characterized in that: The proportions of pure water, a mixture of silver nitrate and silver cyanide, and ammonia water are: 20-30 L: 18-22 g: 0.024-0.036 L; In the mixture of silver nitrate and silver cyanide, the weight proportion 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 dilution 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°C.

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 nickel chloride is 5-15 g / L; The final concentration of the sodium sulfamate is 1-3 g / L; The final concentration of the sodium dodecylbenzene sulfonate 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 OP-10 aqueous solution, wherein the mass concentration of OP-10 in the OP-10 aqueous solution is 1%; The phenolic compound includes, for example, 2,6-di-tert-butyl-p-methylphenol and / or phenolphthalein; the final concentration of the phenolic compound is 1-1.5 g / L.

6. A lightweight electromagnetic shielding multi-element metal fabric prepared by the method according to any one of claims 1 to 5.

7. The lightweight electromagnetic shielding multi-element metal fabric according to claim 6, characterized in that: The thickness of the lightweight electromagnetic shielding multi-element metal fabric is 0.095±0.005 mm, wherein the thickness of the metal layer is 3 microns; The metal content is 29% ± 3%, of which the silver content is 18% ± 2%, and the balance is nickel; The gram weight of the lightweight electromagnetic shielding multi-element metal fabric is 65-68 g / m 2 ; The electrical resistance in the lightweight electromagnetic shielding multi-element metal fabric is 130-190 milliohms / cm.

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