阅读说明：本技术 一种多功能隐身柔性材料及其制备方法 (Multifunctional stealth flexible material and preparation method thereof ) 是由 叶伟 张杏 孙启龙 龙啸云 高强 季涛 于 2021-08-30 设计创作，主要内容包括：本发明涉及一种多功能隐身柔性材料及其制备方法,该材料是在具有可见光隐身功能的面料上,复合电磁波损耗层和红外隐身层,然后功能面再复合无纺布所得,所述的复合电磁波损耗层是将短切的纤维状电磁波吸收材料(活性炭纤维与镀镍碳纤维按质量比1:2-10的混合物)以静电植绒的方式负载的垂直结构。红外隐身层是微胶囊包覆的相变材料的水性聚氨酯水溶液负载后干燥所得。本发明将纤维状电磁波吸收材料以静电植绒的方式形成一个垂直结构的电磁波损耗层,如同尖劈结构材料,一方面可以使电磁波易于进入材料内部进行损耗吸收,另一方面可以增强多重反射损耗。然后采用石蜡相变材料作为红外隐身材料,制备出来面料不仅具有可见光隐身,还兼具红外和雷达隐身。(The invention relates to a multifunctional stealth flexible material and a preparation method thereof, the material is obtained by compounding an electromagnetic wave loss layer and an infrared stealth layer on a fabric with a visible light stealth function, and then compounding non-woven fabrics on a functional surface, wherein the composite electromagnetic wave loss layer is a vertical structure loaded by a short fiber-shaped electromagnetic wave absorption material (a mixture of activated carbon fibers and nickel-plated carbon fibers according to a mass ratio of 1: 2-10) in an electrostatic flocking manner. The infrared stealth layer is obtained by drying the loaded aqueous polyurethane solution of the microcapsule-coated phase-change material. The invention forms the fiber electromagnetic wave absorbing material into a vertical electromagnetic wave loss layer in an electrostatic flocking mode, like a wedge-shaped material, on one hand, the electromagnetic wave can easily enter the material for loss absorption, and on the other hand, the multiple reflection loss can be enhanced. Then, the paraffin phase-change material is used as an infrared stealth material, and the prepared fabric has visible light stealth and infrared and radar stealth functions.)

1. A multifunctional stealth flexible material is characterized in that a fabric with a visible light stealth function is subjected to plasma treatment and is compounded with an electromagnetic wave loss layer and an infrared stealth layer, wherein the electromagnetic wave loss layer is a vertical structure formed by a fibrous electromagnetic wave absorption material in an electrostatic flocking mode.

2. The multifunctional stealthy flexible material of claim 1, wherein the visible stealthy fabric is a camouflage fabric.

3. The preparation method of the multifunctional stealth flexible material as claimed in claim 1, characterized by comprising the following steps:

(1) the camouflage fabric with the visible light stealth function is selected, and plasma treatment is carried out on the reverse side of the fabric, so that the surface hydrophilicity is improved;

(2) adding the microcapsule-coated phase-change material into the adhesive, and then uniformly stirring to prepare a phase-change material solution with the concentration of 10-70 wt%;

(3) spraying the phase-change material solution obtained in the step (2) onto the same side of the fabric subjected to plasma treatment in the step (1), controlling the spraying amount to be 20-50 g/square meter, and preparing the plasma fabric sprayed with the phase-change material;

(4) chopping the electromagnetic wave absorption material, and controlling the length of the fiber to be 1-5 mm; the electromagnetic wave absorption material is a mixture of activated carbon fibers and nickel-plated carbon fibers according to a mass ratio of 1: 2-10;

(5) vertically loading the short-cut electromagnetic wave absorption material to the surface, containing the gel, of the plasma fabric sprayed with the phase change material, obtained in the step (3) in an electrostatic flocking mode, and drying to obtain an electromagnetic wave loss layer with a vertical structure, wherein the short-cut electromagnetic wave absorption material is vertically arranged on the surface of the fabric;

(6) spraying the phase change material solution obtained in the step (2) onto the vertical suede of the material obtained in the step (5) in a low-pressure atomization mode, and then drying at 80 ℃, wherein the spraying amount is controlled to be 50-100 g/square meter;

(7) and (4) compounding the non-woven fabric with the fabric obtained in the step (6), wherein the prepared material has good visible light, infrared and radar stealth functions.

4. The preparation method of the multifunctional stealth flexible material according to claim 3, wherein the microcapsule-coated phase change material is a paraffin microcapsule phase change material, a fatty acid phase change material; the adhesive is water-based polyurethane or polyvinylidene fluoride emulsion.

5. The preparation method of the multifunctional stealth flexible material according to claim 3, characterized in that in the step (5), the drying temperature is below 80 ℃, the load capacity is 50-200g per square meter, the electrostatic flocking voltage is 30-80Kv, and the electrifying time is 2-10 seconds.

Technical Field

The invention relates to a stealth flexible material and a preparation method thereof, which have the functions of visible light stealth, infrared stealth and radar stealth and belong to the technical field of materials.

Background

At present, camouflage technology plays an important role in military equipment of various countries, and particularly, multifunctional composite materials integrating stealth technologies such as visible light, infrared and radar are hot spots of current research. As a flexible stealth material, the flexible stealth material can be widely used for camouflage of objects such as awning covers, patches and the like, but when visible light, infrared and radar stealth materials are compounded, the mutual interference phenomenon exists, and the problems need to be solved through specific material combination and modification.

The invention patent application with publication number CN112851986A, applied by Beijing university of science and engineering in 2021.03.19 discloses a preparation method of a flexible wave-absorbing composite material. Firstly, mixing gallium-based liquid metal and ferrite wave-absorbing powder, and then filling the mixture into pores of expanded graphite to prepare filled expanded graphite; preparing polyvinylidene fluoride, a solvent and an additive into a solution, and then adding filled expanded graphite to obtain a composite membrane casting solution; and finally, uniformly coating the composite casting solution on a support, putting the support into a deionized water gel bath, and obtaining the gallium-based liquid metal/ferrite/expanded graphite/tetrapod-like zinc oxide whisker/polyvinylidene fluoride flexible wave-absorbing composite material by a lyotropic phase conversion method. Has the advantages of simple process, simple operation and low cost. The prepared composite material has the advantages of good flexibility, wave-absorbing performance, hydrophobicity, wear resistance, mechanical property and high-temperature resistance, and has good engineering application prospect in the fields of electromagnetic protection and stealth.

An invention application with publication number CN112666637A of 2020.12.29 at Zhejiang university discloses a lambertian surface-based flexible thermal infrared stealth device and a preparation method thereof, aiming at being compatible with low infrared heat radiation and low total-space reflection of an external infrared heat source so as to reduce the influence of the external heat source on thermal infrared stealth and realize a stealth effect which is safer than most of the thermal infrared stealth materials or devices proposed before. The device comprises a rough substrate and an infrared stealth layer above the substrate, and satisfies the following conditions: the infrared emissivity of the wave bands of 3-5 mu m and 8-14 mu m is less than 0.2; the infrared light reflection characteristics of the wave bands of 3-5 mu m and 8-14 mu m are close to perfect diffuse reflection. The excellent flexibility and heat resistance of the invention can increase the application range of the thermal infrared stealth of the device.

The patent granted by publication No. CN103774328B of Nantong university' 2014.02.10 discloses a processing method of a suede structure fabric for absorbing broadband electromagnetic waves, which selects conductive fiber blended yarns to weave, or selects conductive fiber blended yarns to weave double-layer fabrics; diluting and mixing the wave absorbing agent and the flexible adhesive uniformly to prepare the wave absorbing adhesive with good adhesive property; soaking the pile of the prepared single-side suede fabric in the prepared wave-absorbing adhesive; padding the obtained suede fabric with proper pressure, and extruding redundant wave-absorbing adhesive; and (3) placing the obtained suede fabric in an oven for baking to prepare the broadband electromagnetic wave absorption special fabric with the suede structure. The frequency range of the absorption electromagnetic waves of the broadband electromagnetic wave absorption fabric with the suede structure is about 300 MHz-40 GHz, and the broadband electromagnetic wave absorption fabric can be used as an important biological health protection and facility safety protection product, so that the harm caused by electromagnetic wave radiation is eliminated fundamentally.

Disclosure of Invention

In order to solve the problem of singleness of the existing camouflage products in the aspects of visible light, infrared, radar stealth and the like, the invention aims to provide a multifunctional stealth flexible material and a preparation method thereof, aiming at the improvement technology of the patent CN103774328B, the selected electromagnetic wave absorbent is more effective, and the electromagnetic wave loss fiber material is erected on the surface of the fabric in the modes of electrostatic flocking, spraying and the like to form an effective electromagnetic wave loss layer, and the multifunctional camouflage material also has the functions of visible light and infrared stealth.

To solve the above technical problems, the present invention has been accomplished in such a manner

A stealth flexible material is formed by sequentially compounding an electromagnetic wave loss layer and an infrared stealth layer on a non-woven fabric composite layer.

The preparation method comprises the following steps:

(1) the camouflage fabric with the visible light stealth function is selected, and then plasma treatment is carried out on the reverse side of the fabric, so that the surface hydrophilicity is improved.

(2) Adding 10-70g of microcapsule-coated phase-change material into 20-100g of adhesive, and then uniformly stirring to prepare a phase-change material solution with the concentration of 10-70%; the preferred concentration is 70% because at this concentration, a lower infrared emissivity is obtained.

The phase change material coated by the microcapsule is a paraffin microcapsule phase change material or a fatty acid phase change material, and the phase change material has better infrared emissivity;

the adhesive is water-based polyurethane or polyvinylidene fluoride emulsion.

(3) And (3) spraying the phase-change material solution obtained in the step (2) onto the same side of the fabric subjected to plasma treatment, wherein the spraying amount is controlled to be 20-50 g/square meter, and preparing the plasma fabric sprayed with the phase-change material.

(4) Chopping the electromagnetic wave absorption material, and controlling the length of the fiber to be 1-5 mm; the electromagnetic wave absorbing material is a mixture of activated carbon fibers and nickel-plated carbon fibers in a mass ratio of 1:2-10, and the purpose of controlling the load fastness and the fabric thickness is achieved by adopting the fibers with the length.

(5) And (3) vertically loading the short-cut electromagnetic wave absorption material to the surface, containing the gel, of the plasma fabric sprayed with the phase change material, obtained in the step (3) in an electrostatic flocking mode, and drying to obtain an electromagnetic wave loss layer with a vertical structure, wherein the short-cut electromagnetic wave absorption material is erected on the surface of the fabric, and the structure has excellent electromagnetic wave absorption performance.

The drying temperature is below 80 ℃, the loading capacity is 50-200 g/square meter, the electrostatic flocking voltage is 30-80Kv, and the electrifying time is 2-10 seconds.

(6) And (3) spraying the phase change material solution obtained in the step (2) to the vertical suede of the material obtained in the step (5) in a low-pressure atomization mode, and then drying at 80 ℃, wherein the spraying amount is controlled to be 50-100 g/square meter.

(7) And (3) compounding non-woven fabrics of 50 g/square meter with the fabrics obtained in the step (6) to prepare the multifunctional stealth material, wherein the prepared material has good visible light, infrared and radar stealth functions.

Has the advantages that: according to the stealth flexible material, the fibrous electromagnetic wave absorption material is flocked in an electrostatic flocking manner to form the electromagnetic wave loss layer with a vertical structure, like a wedge-shaped structure material, so that the electromagnetic wave can easily enter the material to be lost and absorbed on one hand, and the multiple reflection loss can be enhanced on the other hand. Then, a paraffin phase-change material is adopted as the infrared stealth material. The prepared fabric has the advantages of visible light stealth, infrared stealth and radar stealth.

Drawings

FIG. 1 is a block diagram of the material of the present invention;

FIG. 2 is an electromagnetic wave loss simulation diagram, in which a fiber erecting structure adopted by the invention is beneficial to multiple reflections of electromagnetic waves for loss;

FIG. 3 is the electromagnetic wave loss curve chart of example 4, and it can be seen that the electromagnetic wave loss of the material between 9 and 18GHz is < -10dB, and the lowest loss reaches-18 dB.

1-visible light protective layer, 2-radar, infrared protective layer, 3-non-woven fabric composite layer and 4-electromagnetic wave.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

The paraffin microcapsule phase change material used in the following examples was purchased from Shandong Toyobo plastics Co., Ltd, model number PCM-40.

Example 1

(1) Selecting a camouflage fabric with a visible light camouflage function, and then carrying out plasma treatment on the reverse side of the fabric to improve the surface hydrophilicity;

(2) adding 10g of paraffin microcapsule phase change material into 100g of waterborne polyurethane, and then uniformly stirring to prepare a mixed solution with the concentration of 10%;

(3) spraying the phase-change microcapsule solution prepared in the step 2 on one surface of the fabric subjected to plasma treatment in the step 1, wherein the spraying amount is controlled to be 50g per square meter;

(4) mixing 3mm of activated carbon fiber and 5mm of nickel-plated carbon fiber in a mass ratio of 1:2 to prepare an electromagnetic wave absorbent;

(5) loading an electromagnetic wave absorbent on one side containing glue of S3 by an electrostatic flocking mode, drying at 80 ℃, controlling the quantity of S4 to be 50 g/square meter, and preparing an electromagnetic wave loss layer with a special vertical structure; the electrostatic flocking voltage is 30Kv, and the electrifying time is 5 seconds;

(6) spraying the phase-change microcapsule solution prepared in the step 2 on the flocking surface of the electrostatic flocking in a low-pressure atomization mode, wherein the spraying amount is 100 g/square meter, and then drying at 80 ℃;

(7) and (3) compounding non-woven fabrics of 50 grams per square meter with the material suede prepared in the step (6) to prepare the multifunctional stealth material.

Examples 1-3 examination of the effect of process conditions on the results is shown in Table 1:

TABLE 1

Based on the results of examples 1-4, it was found that the IR emissivity becomes lower as the content of the phase change material increases, and the thermal IR protection performance of the material can be improved by the coating and loading of the phase change material.

The length, mixing ratio and loading capacity of the activated carbon fiber and the nickel-plated carbon fiber can influence the electromagnetic wave loss performance of the material; the conductivity of the activated carbon fiber is too high, so that the activated carbon fiber is connected into a piece with too high content to form a conductive net, so that electromagnetic waves are reflected rather than lost; meanwhile, the length of the fiber is increased as much as possible under the condition of keeping certain rigidity of the fiber and the thickness of the fabric, and the electrostatic flocking enables the fiber to be in a vertical state, so that electromagnetic waves can be multiply reflected among the fibers to increase loss; the electromagnetic wave absorbent active carbon fiber and nickel plating fiber are too low to cause insufficient electromagnetic wave loss, and too high to cause insufficient electromagnetic wave loss.

The loading of fabric surface fibers is controlled through voltage and time in electrostatic flocking, and spraying of phase change microcapsule polyurethane solution is carried out through a low-pressure spraying mode, so that the electrostatic flocking fibers are firmer, phase change materials can be well inlaid among the fibers, the infrared protection performance is improved, and the vertical state of the fibers can be greatly maintained in a low-pressure mode. Therefore, the best process condition determined by the process screening is example 4.

The above embodiments do not limit the technical solutions of the present invention in any way, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.