阅读说明：本技术 一种吸波型电磁屏蔽织物的超临界二氧化碳后整理工艺 (Supercritical carbon dioxide after-finishing process of wave-absorbing electromagnetic shielding fabric ) 是由 侯琳 徐炎炎 刘琳 蔡普宁 樊争科 王超 于 2021-09-06 设计创作，主要内容包括：本发明提供一种吸波型电磁屏蔽织物的超临界二氧化碳后整理工艺,所述的整理方法为超临界二氧化碳后整理工艺,该后整理工艺流程无水参与,可以解决复合吸波粉体在水相中难以均匀分散的技术难题。采用本发明的后整理加工方式处理的吸波型电磁屏蔽织物具有“厚度薄、质量轻、频带宽、反射损耗能力强”等特点,同时兼具阻燃、耐辐射的性能,采用本发明超临界技术处理的吸波型电磁屏蔽织物可用来开发各种电磁屏蔽安全防护服,广泛应用于民用和军事领域。(The invention provides a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric, wherein the finishing method is the supercritical carbon dioxide after-finishing process, the after-finishing process flow has no water participation, and the technical problem that composite wave-absorbing powder is difficult to uniformly disperse in a water phase can be solved. The wave-absorbing electromagnetic shielding fabric treated by the post-finishing processing mode has the characteristics of thin thickness, light weight, wide frequency band, strong reflection loss capability and the like, has the performances of flame retardance and radiation resistance, can be used for developing various electromagnetic shielding safety protective clothing, and is widely applied to the civil and military fields.)

1. A supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric comprises the following specific steps:

(1) pretreatment of the fabric: the fabric pretreatment agent is one or a mixture of ethanol and acetone, and is dried for later use after treatment;

(2) and (3) supercritical carbon dioxide after finishing: placing a certain amount of the fabric treated in the step (1) in a high-temperature high-pressure reaction kettle, simultaneously placing a certain amount of wave-absorbing nano powder and entrainer mixture in a feeding kettle, introducing the carbon dioxide fluid which is in a supercritical state after being heated and pressurized into the feeding kettle at a certain flow rate, mixing and dissolving the carbon dioxide fluid with the wave-absorbing nano powder and the entrainer to form a finishing agent, and under the action of a circulating device, enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid, wherein the finishing process shows the characteristic of dynamic circulation so that the finishing effect is more sufficient; under the conditions of certain process temperature and pressure, the composite wave-absorbing material dissolved in the supercritical carbon dioxide fluid is fully contacted with the fabric and then is dispersed into the fiber to realize after-finishing;

(3) and (3) post-treatment: reducing the reaction temperature and pressure after a period of time to ensure that the unused wave-absorbing powder and CO₂Separated in a separation kettle, the wave-absorbing material which is not arranged can be recycled, and simultaneously, the gaseous state isCO₂The reflux collection can also be reused; thus, a complete post-finishing process is completed.

2. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein the fabric is formed by blending two or more kinds of intrinsic flame-retardant fibers such as meta-aramid fibers, flame-retardant viscose, flame-retardant polyester fibers and the like.

3. The supercritical carbon dioxide after-finishing process for the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein in the step (1), the treatment temperature is 40-60 ℃, the treatment time is 40-60 min, and the drying temperature is 60-80 ℃.

4. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein the wave-absorbing powder is a composite wave-absorbing powder.

5. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein the composite wave-absorbing powder is selected from nano wave-absorbing materials such as graphene, carbon nanotube, ferrite and MXene-Ti₃C_2-More than one of (1).

6. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 5, wherein the composite wave-absorbing powder is prepared from nano wave-absorbing materials such as graphene, carbon nanotube, ferrite and MXene-Ti₃C₂And compounding.

7. The supercritical carbon dioxide after-finishing process for the wave-absorbing electromagnetic shielding fabric according to claim 1, comprising graphene, carbon nanotubes, ferrite and MXene-Ti₃C₂The mass ratio is about 4:3:2: 1.

8. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein the entrainer comprises nonpolar hydrocarbon substances such as n-hexane, cyclohexane and pentane.

9. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric, according to claim 1, wherein the finishing temperature is 80-260 ℃, the pressure is 18-36 MPa, the finishing time is 40-100 min, and the flow rate of carbon dioxide is 20-50 g/min.

10. The supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric according to claim 1, wherein the wave-absorbing nano powder accounts for 10-25% of the fabric to be finished, and the entrainer accounts for 3-5% of the fabric to be finished.

Technical Field

The invention relates to the technical field of functional textiles, in particular to a preparation method of an electromagnetic shielding fabric and a supercritical carbon dioxide after-finishing process.

Background

With the development of technologies such as intelligent communication systems, wireless network devices, electronic detection devices and the like, electromagnetic pollution, which is a novel invisible, untouchable and inaudible pollution, is related to the surroundings of people's life, harms human health, and is listed as one of world public hazards. In order to effectively shield the interference of electromagnetic waves and reduce the harm of the electromagnetic waves to human beings and the environment, it is important to develop an efficient electromagnetic shielding fabric.

At first, people develop electromagnetic shielding protective clothing by utilizing a mixed woven fabric of metal wires and decorative fibers, the electromagnetic shielding protective clothing has a certain shielding effect on electromagnetic radiation, but the clothing is hard, thick and heavy in hand feeling and poor in wearability. On the basis, the metal fiber blended fabric is produced, and the wearability of the metal fiber blended fabric is greatly improved. However, since many fibers are difficult to mix uniformly, the shielding property is not satisfactory, and there are also tip discharge and itching phenomena. Then, silver-plated fabrics and fabrics containing multiple elements or multiple ions appear, the electromagnetic shielding fabrics mainly reflect electromagnetic waves and bring secondary pollution to the electromagnetic waves, and the shielding materials mainly absorbing waves can convert the electromagnetic wave energy into other forms of energy to achieve the shielding effect. Based on this, the development of the wave-absorbing electromagnetic shielding fabric is imperative.

CN109208333A discloses a method for constructing a wave-absorbing electromagnetic shielding composite coating fabric, which comprises the steps of soaking cotton fabrics pretreated by alkali liquor in carbon nano tube dispersion liquid for coating treatment, then sequentially soaking the cotton fabrics by pyrrole solution and carrying out oxidative polymerization by an oxidant to form a carbon nano tube/polypyrrole coated fabric, and finally sequentially carrying out acid soaking and vacuum drying to obtain the wave-absorbing electromagnetic shielding composite coating fabric. The electromagnetic shielding fabric with shielding effectiveness exceeding 20dB at a frequency band of 3.5-6GHz is prepared by using a step-by-step assembly technology, and can meet commercial shielding requirements.

CN107988787A discloses a preparation method of a wave-absorbing electromagnetic shielding fabric, which comprises the following steps: step 1, soaking a cotton fabric in alkali liquor, oscillating at constant temperature, washing with water to be neutral, and then drying; step 2, preparing a carbon nano tube dispersion liquid, wherein the concentration ratio of the carbon nano tubes to the surfactant in the dispersion liquid is 0.05-0.25: 1; step 3, soaking the cotton fabric dried in the step 1 in the carbon nano tube dispersion liquid; and 4, taking out the cotton fabric dipped in the step 3, and drying to obtain the cotton fabric. The finishing process of the invention has no water participation in the whole process and has the characteristic of dynamic circulation, so that the prepared electromagnetic shielding fabric has excellent shielding and wave absorbing performance.

There are two development approaches for the wave-absorbing electromagnetic shielding fabric. One is to use magnetic conductive wave-absorbing material with magnetic conductivity, such as ferrite, metal micro powder (including carbonyl metal and magnetic metal micro powder) to prepare wave-absorbing fiber. In the process of preparing the fiber, the prepared fiber has a wave absorbing function, the addition amount of the wave absorbing material in the polymer matrix cannot be too low, and the performance of the prepared fiber can hardly meet the basic requirements of the fiber for spinning due to the excessively high addition amount of the wave absorbing material. The other development method of the electromagnetic shielding fabric is to adopt coating finishing, but the processing procedure is relatively complex to control, the processed fabric has hard hand feeling, poor washing resistance and oxidation resistance and high cost, and brings great difficulty to practical production and application.

Supercritical fluid technology is widely used due to its advantages of high efficiency, green, environmental protection, high diffusion coefficient, strong dissolving capacity, etc. Wherein the carbon dioxide can be converted into a supercritical fluid at a relatively low temperature and pressure, and can dissolve a variety of non-polar substances.

The invention adopts supercritical CO₂In the technology of fluid flow, the flow rate of the fluid,the supercritical fluid dissolved composite wave-absorbing material is formed at a certain temperature and pressure, and the supercritical carbon dioxide fluid has extremely strong diffusion performance, so that the shielding materials (graphene, carbon nano tube, ferrite and MXene-Ti) can be prepared₃C₂Etc.) in a dispersed state and further loaded into the interior of the fiber matrix. The wave-absorbing electromagnetic shielding fabric treated by the post-finishing processing mode has the characteristics of thin thickness, light weight, wide frequency band, strong reflection loss capability and the like, has the performances of flame retardance and radiation resistance, can be used for developing various electromagnetic shielding safety protective clothing, and is widely applied to the civil and military fields.

Disclosure of Invention

The embodiment of the invention provides a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric, which aims to overcome the defects that the traditional electromagnetic shielding fabric is easy to corrode, oxidize or react with other chemical substances, is difficult to process, has high density and limited physical elasticity, and is easy to generate eddy current and secondary pollution.

Specifically, the invention provides a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric, which comprises the following steps:

a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric is characterized in that the finishing method is a supercritical carbon dioxide after-finishing process, the after-finishing process flow has no water participation, and the technical problem that composite wave-absorbing powder is difficult to uniformly disperse in a water phase can be solved.

The method comprises the following specific steps:

(1) pretreatment of the fabric: the fabric pretreating agent is one or a mixture of ethanol and acetone, and is dried for later use after treatment.

(2) And (3) supercritical carbon dioxide after finishing: placing a certain amount of the fabric treated in the step (1) in a high-temperature high-pressure reaction kettle, simultaneously placing a certain amount of wave-absorbing nano powder and entrainer mixture in a feeding kettle, introducing the carbon dioxide fluid which is in a supercritical state after being heated and pressurized into the feeding kettle at a certain flow rate, mixing and dissolving the carbon dioxide fluid with the wave-absorbing nano powder and the entrainer to form a finishing agent, and enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid under the action of a circulating device; under the conditions of certain process temperature and pressure, the composite wave-absorbing material dissolved in the supercritical carbon dioxide fluid is fully contacted with the fabric and then is dispersed into the fiber to realize after-finishing;

(3) and (3) post-treatment: reducing the reaction temperature and pressure after a period of time to ensure that the unused wave-absorbing powder and CO₂Separated in the separation kettle, the wave-absorbing material which is not finished can be recycled, and simultaneously, gaseous CO₂The reflux collection can also be reused; thus, a complete post-finishing process is completed.

In some preferred embodiments, the fabric is blended by two or more fibers of intrinsic flame-retardant fibers such as meta-aramid, flame-retardant viscose, flame-retardant polyester and the like.

In some preferred embodiments, the fabric pretreatment temperature is 40-60 ℃, the treatment time is 40-60 min, and the drying temperature is 60-80 ℃.

In some preferred embodiments, the wave-absorbing powder is a composite wave-absorbing powder.

In some preferred embodiments, the composite wave-absorbing powder is prepared from nano wave-absorbing materials such as graphene, carbon nano tube, ferrite and MXene-Ti by starting from wave-absorbing mechanisms such as magnetic loss and electric loss and aiming at expanding wave-absorbing frequency range₃C₂More than one of (1).

In some preferred embodiments, the composite wave-absorbing powder is prepared from nano wave-absorbing materials such as graphene, carbon nano tube, ferrite and MXene-Ti₃C₂And compounding.

In some preferred embodiments, graphene, carbon nanotubes, ferrite, and MXene-Ti₃C₂The mass ratio is about 4:3:2: 1. In some preferred embodiments, the entrainer comprises a non-polar hydrocarbon such as n-hexane, cyclohexane, pentane, and the like.

In some preferred embodiments, the finishing temperature of the after-finishing process is 80-260 ℃, the pressure is 18-36 MPa, the finishing time is 40-100 min, and the flow rate of carbon dioxide is 20-50 g/min.

In some preferable embodiments, the content of the wave-absorbing nano powder is 10-25% relative to the fabric to be finished.

In some preferred embodiments, the entrainer is present in a relative amount of 3 to 5%.

According to the post-finishing process of the supercritical carbon dioxide wave-absorbing type electromagnetic shielding fabric, provided by the embodiment of the invention, no water is involved in the finishing process, operations such as cleaning and drying are not needed after finishing, the process flow is short, and the process is energy-saving and environment-friendly; and the unused finishing agent and the like can be recycled, and the method has modern processing concepts of cleanness, greenness and environmental protection.

Supercritical CO of the invention₂The finishing process is free from water participation, the composite wave-absorbing nano powder is dissolved in supercritical carbon dioxide fluid under the action of an entrainer, the finishing agent is continuously and fully contacted with a fiber interface along with the circulating flow of the supercritical fluid to generate molecular acting force, the composite wave-absorbing material is adsorbed on the surface of the fiber along with the gradual increase of the acting force between the composite wave-absorbing material molecules and the fiber molecules, at the moment, the concentration difference of the wave-absorbing material is formed inside and outside the fiber, and the supercritical carbon dioxide fluid has certain swelling effect on the textile fiber, so that more composite wave-absorbing materials are gradually transferred to the inside of the fiber. Meanwhile, the composite wave-absorbing material molecules and fiber macromolecules are entangled and adsorbed together to form a stable state through hydrogen bonds or disordered van der Waals force under the action of ultra-strong diffusion of the supercritical carbon dioxide fluid.

The invention solves the technical problem that the nano wave-absorbing materials such as ferrite, metal micro powder, graphene, carbon nano tubes and the like are difficult to uniformly disperse due to agglomeration in a water phase, and in a supercritical carbon dioxide dissolving system, a special lamellar structure of the graphene can be uniformly distributed among the carbon nano tubes, the nano ferrite and other particles, so that the carbon nano tubes and the ferrite are prevented from agglomerating again after dispersion, various wave-absorbing materials can exist in a stable nano state and can be directly applied to textile materials, thereby exerting the specific electrical properties of the nano materials and exerting good electromagnetic shielding and wave-absorbing effects.

The wave-absorbing electromagnetic shielding fabric developed by the invention is mainly applied to electromagnetic radiation pollution areas of factories, scientific research institutions, hospitals, railway stations, communication base stations, video monitoring command stations of the public security department and the like in the civil field. In the military field, the electromagnetic shielding fabric can be used for developing various electromagnetic shielding textiles to meet the requirements of normal operation, electromagnetic information shielding and information protection, electromagnetic stealth and the like of various electronic equipment.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings of the apparatuses required to be used in the description of the embodiments, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a flow chart of a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric provided by an embodiment of the invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The invention discloses a supercritical carbon dioxide after-finishing process of a wave-absorbing electromagnetic shielding fabric, which has the approximate flow as shown in figure 1 and comprises the following specific steps:

(1) and (4) pretreating the fabric. The fabric pretreating agent is one or a mixture of ethanol and acetone. The treatment temperature is 40-60 ℃, the treatment time is 40-60 min, and the drying temperature is 60-80 ℃.

(2) And (5) performing supercritical carbon dioxide after finishing. And (2) placing a certain amount of the fabric treated in the step (1) in a high-temperature high-pressure reaction kettle, and simultaneously placing a mixture of 10-25% of the composite wave-absorbing nano powder and 3-5% of the entrainer in the fabric in a feeding kettle. Wherein the composite wave-absorbing powder comprises graphene, carbon nano tubes, ferrite and MXene-Ti₃C₂The mass ratio of the four is controlled to be 4:3:2: 1. And (2) introducing the carbon dioxide in the supercritical state after being heated and pressurized into the feeding kettle at the flow rate of 20-50 g/min, mixing and dissolving the carbon dioxide with the composite wave-absorbing nano powder and the entrainer to form a finishing agent, and enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid under the action of a circulating device. At the temperature of 80-260 ℃ and under the pressure of 18-36 MPa, the composite wave-absorbing material dissolved in supercritical carbon dioxide is fully contacted with the fabric, then enters the fiber to realize after-finishing, the reaction temperature and pressure are reduced after the treatment for 40-100 min, and the unused composite wave-absorbing material and gaseous CO are recycled₂And finally obtaining the wave-absorbing electromagnetic shielding fabric.

It should be noted that the above-mentioned embodiments of the method are described as a series of actions for simplicity of description, but those skilled in the art should understand that the present invention is not limited by the described sequence of actions. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

In order to further understand the present invention, the following describes the supercritical carbon dioxide after-finishing process method of the wave-absorbing electromagnetic shielding fabric according to the present invention with reference to specific embodiments.

Example one

(1) And (4) pretreating the fabric. And pretreating the meta-aramid fabric by using acetone. The treatment temperature is 60 ℃, the treatment time is 40min, and the drying temperature is 80 ℃.

(2) And (5) performing supercritical carbon dioxide after finishing. Get m₁Putting the fabric treated in the step (1) into a high-temperature high-pressure reaction kettle, and simultaneously putting the fabric with the mass of 0.25m₁Gram of composite wave-absorbing nano powder and 0.05m₁Grams of entrainer mixture was placed in the addition kettle. Wherein the composite wave-absorbing powder comprises graphene, carbon nano tubes, ferrite and MXene-Ti₃C₂The mass ratio of the four is 4:3:2: 1. And (2) introducing the carbon dioxide in a critical state after temperature rise and pressure rise into the feeding kettle at the flow rate of 20g/min, mixing and dissolving the carbon dioxide with the composite wave-absorbing nano powder and the entrainer to form a finishing agent, and enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid under the action of a circulating device. Under the process conditions of 260 ℃ and 36MPa of pressure, the composite wave-absorbing material dissolved in supercritical carbon dioxide is fully contacted with the fabric and then enters the fiber to realize after-finishing, the reaction temperature and pressure are reduced after 100min of treatment, and the unused composite wave-absorbing material and gaseous CO are recycled₂And finally obtaining the wave-absorbing electromagnetic shielding fabric.

Example two

And (4) pretreating the fabric. The blended fabric of the meta-aramid and the flame-retardant viscose is pretreated by ethanol. The treatment temperature is 40 ℃, the treatment time is 60min, and the drying temperature is 60 ℃.

And (5) performing supercritical carbon dioxide after finishing. Get m₂Putting the fabric treated in the step (1) into a high-temperature high-pressure reaction kettle, and simultaneously putting the fabric with the mass of 0.15m₂Gram composite wave-absorbing nano powder and 0.03m₂Grams of entrainer mixture was placed in the addition kettle. Wherein the composite wave-absorbing powder comprises graphene, carbon nano tubes, ferrite and MXene-Ti₃C₂The mass ratio of the four is 4:3:2: 1. And (2) introducing the carbon dioxide in a critical state after temperature rise and pressure rise into a feeding kettle at the flow rate of 30g/min, mixing and dissolving the carbon dioxide with the composite wave-absorbing nano powder and the entrainer to form a finishing agent, and enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid under the action of a circulating device. Under the process conditions of 220 ℃ and 32MPaThen, the composite wave-absorbing material dissolved in the supercritical carbon dioxide is fully contacted with the fabric and enters the fiber to realize after-finishing, the reaction temperature and the pressure are reduced after the treatment for 60min, and the unused composite wave-absorbing material and gaseous CO are recycled₂And finally obtaining the wave-absorbing electromagnetic shielding fabric.

EXAMPLE III

And (4) pretreating the fabric. And (3) pretreating the flame-retardant polyester and flame-retardant viscose blended fabric by adopting ethanol. The treatment temperature is 50 ℃, the treatment time is 50min, and the drying temperature is 60 ℃.

And (5) performing supercritical carbon dioxide after finishing. Get m₃Putting the fabric treated in the step (1) into a high-temperature high-pressure reaction kettle, and simultaneously putting the fabric with the mass of 0.1m₃Gram composite wave-absorbing nano powder and 0.03m₃Grams of entrainer mixture was placed in the addition kettle. Wherein the composite wave-absorbing powder comprises graphene, carbon nano tubes, ferrite and MXene-Ti₃C₂The mass ratio of the four is 4:3:2: 1. And (2) introducing the carbon dioxide in a critical state after temperature rise and pressure rise into a feeding kettle at the flow rate of 30g/min, mixing and dissolving the carbon dioxide with the composite wave-absorbing nano powder and the entrainer to form a finishing agent, and enabling the formed finishing agent to flow back and forth between the feeding kettle and the reaction kettle along with the supercritical carbon dioxide fluid under the action of a circulating device. Under the process conditions of 80 ℃ and 20MPa of pressure, the composite wave-absorbing material dissolved in supercritical carbon dioxide is fully contacted with the fabric and then enters the fiber to realize after-finishing, the reaction temperature and pressure are reduced after the treatment for 60min, and the unused composite wave-absorbing material and gaseous CO are recycled₂And finally obtaining the wave-absorbing electromagnetic shielding fabric.

Electromagnetic shielding performance test

In order to verify the performance of the prepared fabric, the shielding performance of the 3-layer wave-absorbing electromagnetic shielding fabric prepared in the embodiment 1-3 is performed according to GJB 6190-.

Meanwhile, in order to verify the electromagnetic shielding performance of the sample after the supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric, the performance comparison test is carried out on the wave-absorbing electromagnetic shielding fabric and the wave-absorbing electromagnetic shielding fabric commercialized in the market. Electromagnetic shielding fabric (silver loaded) of a certain manufacturer of Qingdao Shandong was used as a sample of comparative example one.

In addition, the positive influence of the supercritical carbon dioxide after-finishing process of the wave-absorbing electromagnetic shielding fabric on the shielding performance of the fabric is highlighted for longitudinal comparison. The fabric pretreated in example 1 was used without the supercritical carbon dioxide finishing process, and the sample obtained by the conventional finishing process was the comparative example two. In the compared sample, the meta-aramid fiber, the flame-retardant viscose and the flame-retardant polyester do not have the wave absorbing function, so that the influence of the meta-aramid fiber, the flame-retardant viscose and the flame-retardant polyester on the electromagnetic shielding and wave absorbing performance of the sample is ignored during the comparison analysis. Five fabrics were cut out as test samples from five different regions of the samples of examples one to three and two comparative examples, respectively, with the test band set at 4GHz to 14GHz, and the test results are shown in table 1.

Table 1 electromagnetic shielding and emissivity test results of each sample

The test results show that in the aspect of shielding performance, the average value of the electromagnetic shielding performance of the first embodiment is 53.0dB, the average value of the electromagnetic shielding performance of the second embodiment is 48.0dB, and the average value of the electromagnetic shielding performance of the third embodiment is 42.9dB in the 4 GHz-14 GHz wave band. Compared with the shielding performance of the first and second comparative examples, the electromagnetic shielding performance of the wave-absorbing electromagnetic shielding fabric treated by the supercritical carbon dioxide after-finishing process is improved by more than 30%. In the aspect of wave-absorbing performance, the average value of the reflectivity of the first embodiment is-26.9 dB, and the average value of the reflectivity of the first comparative example is-2.5 dB, so that compared with the traditional electromagnetic shielding fabric, the wave-absorbing electromagnetic shielding fabric developed by the method has excellent wave-absorbing performance, the average value of the reflectivity of the second comparative example is-11.6 dB, the content and the uniformity of wave-absorbing composite powder in the fabric distribution can be improved by using the supercritical carbon dioxide after-finishing process, and the prepared wave-absorbing electromagnetic shielding fabric has excellent wave-absorbing performance. Meanwhile, the test results show that the data dispersion coefficients of the shielding performance and the wave absorbing performance of different areas are small, and the carbon dioxide supercritical after-finishing process provided by the invention also shows that the dispersibility of the wave absorbing powder in the system is improved.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.