Preparation method and application of microwave radiation-controlled composite material

Abstract

The present invention provides a preparation method and application of a microwave radiation regulation composite material. The preparation method of the microwave radiation regulation composite material comprises: laying an aramid paper honeycomb on a bottom plate; providing a filling template, wherein the filling template is provided with through holes, and the filling template is placed on the upper surface of the aramid paper honeycomb, and the through holes of the filling template correspond to the pores of the aramid paper honeycomb; using the filling template, adding filler into the pores of the aramid paper honeycomb; after the filler is added, removing the filling template, laying a panel on the upper surface of the aramid paper honeycomb to form a blank; and molding the blank to obtain the microwave radiation regulation composite material. The present invention adopts a periodic hollow flat plate carved according to a pattern matching the size of the honeycomb pores as the filling template for filling. The method is simple and easy to implement, has high efficiency, is suitable for mass production, and can be filled with different types of fillers, providing higher design flexibility for microwave radiation regulation performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave radiation controlled composite materials, and in particular relates to a preparation method and application of a microwave radiation controlled composite material. Background Art

[0002] Traditional absorbing microwave radiation control composite materials are composed of absorbing honeycomb core materials or absorbing foam core materials with panels attached to the upper and lower surfaces. In order to achieve the radiation control of low-frequency and broadband (L, S, C, X, and Ku bands) electromagnetic waves, the absorbing core material is designed to be stacked with multiple single absorbing layers to form an impedance matching structure. Even so, the bandwidth of microwave radiation control is still limited. In particular, it is difficult to effectively balance the radiation control of low-frequency and high-frequency microwaves. In addition, there are many bonding interfaces between the layers, which increases the risk of debonding between the layers during engineering applications.

[0003] Researchers have proposed a multi-mechanism collaborative microwave radiation control composite material design method to overcome the above technical bottleneck. The method involves periodically filling the honeycomb cells with absorbing foam in a patterned manner, forming a honeycomb / foam superstructure with periodic units that regulate phase coupling losses for low-frequency electromagnetic waves and absorption losses for high-frequency electromagnetic waves. This design method is effective in controlling broadband microwave radiation. Existing methods for preparing such periodic structures first use plugs to partially block the honeycomb cells, then add absorbing foaming material to the unblocked honeycomb cells for foaming, and finally remove the plugs to form a periodic repeating unit with alternating absorbing foam-filled cells and honeycomb spaces. This method has the following shortcomings: (1) The honeycomb is an array structure with numerous and small honeycomb holes. The honeycomb holes are pre-occupied by plugs and then removed after foaming, which is very inefficient and not suitable for mass production; (2) The foaming material expands and foams in the pores. Due to the presence of the pore skeleton, the foaming and squeezing of the honeycomb wall cannot be initiated freely, and the foaming is restricted, resulting in uneven foaming and affecting the performance stability; (3) The microwave-absorbing foam filled in the periodic unit honeycomb pores is the same, which limits the flexibility of the design of microwave radiation control performance.

[0004] In summary, in order to overcome the shortcomings of the existing technology, it is necessary to propose a preparation method for microwave radiation-controlled composite materials that is simple, efficient, suitable for mass production, and has high performance stability of the products produced, while also being able to improve the flexibility of performance design. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of a microwave radiation-controlled composite material, aiming to provide a preparation method of a microwave radiation-controlled composite material that is simple, efficient, suitable for mass production, and has high performance stability of the produced products, while also being able to improve the flexibility of performance design.

[0006] To achieve the above object, the present invention provides a method for preparing a microwave radiation-controlled composite material, comprising the following steps:

[0007] S10, laying the aramid paper honeycomb on the bottom plate;

[0008] S20, providing a filling template, wherein the filling template is provided with vias, and placing the filling template on the upper surface of the aramid paper honeycomb, with the vias of the filling template corresponding to the cells of the aramid paper honeycomb;

[0009] S30, adding filler into the aramid paper honeycomb cells through the filling template;

[0010] S40, after the filler is added, the filling template is removed, and a panel is laid on the upper surface of the aramid paper honeycomb to form a blank;

[0011] S50, molding the blank to obtain a microwave radiation controlled composite material.

[0012] Optionally, in step S10, the cells of the aramid paper honeycomb are regular hexagons, and the side length of the regular hexagon is 4.5 to 35 mm.

[0013] Optionally, in step S20, the thickness of the filling template is 0.2-1 mm; and / or the thickness of the aramid paper honeycomb is 5-100 mm.

[0014] Optionally, in step S30, the filler includes spherical wave-absorbing foam particles, and the wave-absorbing foam particles include any one of polyurethane wave-absorbing foam particles and polymethacrylimide foam particles.

[0015] Optionally, the particle size of the wave-absorbing foam particles is 0.2 to 3 mm.

[0016] Optionally, in step S10, the bottom plate includes a carbon fiber plate, and the thickness of the carbon fiber plate is 0.2-1 mm; and / or, in step S40, the panel includes a fiberglass reinforced plastic plate, and the thickness of the fiberglass reinforced plastic plate is 0.2-1 mm.

[0017] Optionally, in step S50, the molding conditions are: the pressure is 0.2 MPa, the temperature is raised from 25-35°C to 80°C and kept for 1 hour, then continued to rise to 120°C and kept for 2 hours, and finally dropped to 25-35°C.

[0018] Optionally, epoxy structural adhesive films are provided on the upper and lower surfaces of the aramid paper honeycomb, respectively, and the upper surface of the aramid paper honeycomb is bonded and fixed to the panel, and the lower surface of the aramid paper honeycomb is bonded and fixed to the bottom plate.

[0019] In addition, the present invention provides a microwave radiation control component for missile launch equipment, including the microwave radiation control composite material prepared by the above-mentioned preparation method of the microwave radiation control composite material.

[0020] In the present invention, a periodic hollow filling template is prepared which is matched with the size of the honeycomb cells and carved according to a certain pattern. The filling template is used to fill the filler. After filling, the composite material has good performance consistency, is simple and easy, has high efficiency, is suitable for mass production, and the filler is densely filled. Different types of fillers can be easily filled into different periodic unit cells, providing higher design flexibility for microwave radiation control performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a flow chart for preparing the composite material regulated by microwave radiation in Example 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the microwave radiation control composite material in Example 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of the core material structure with periodic repeating units in Example 1 provided by the present invention;

[0025] Figure 4 This is a schematic diagram of the filling template in Example 1 provided by the present invention.

[0026] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0028] It should be noted that, in the embodiments, those without specifying specific conditions, are carried out according to conventional conditions or the conditions recommended by the manufacturer. Those for reagents or instruments used that do not specify the manufacturer are conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes schemes A, B, or A and B that meet the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on those of ordinary skill in the art. When the combination of the technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work belong to the scope of protection of the present invention.

[0029] The existing method for preparing periodic structures is to first plug part of the honeycomb cells with a plug, then add the absorbing foam material to the unplugged honeycomb cells for foaming, and finally remove the plug to form a periodic repeating unit with cells filled with absorbing foam and alternating honeycomb spaces. This method has the following disadvantages: (1) The honeycomb is an array structure with small and numerous honeycomb cells. Using the plug to pre-occupy the honeycomb cells and then remove them after foaming is very inefficient and not suitable for mass production; (2) The foam material expands and foams in the cells. Due to the presence of the cell skeleton, the foaming cannot be freely initiated by squeezing the honeycomb wall, which restricts the foaming and causes uneven foaming, affecting the performance stability; (3) The absorbing foam filled in the periodic unit honeycomb cells is the same, which limits the flexibility of the microwave radiation control performance design.

[0030] In view of this, the present invention provides a method for preparing a microwave radiation control composite material, comprising the following steps: S10, laying an aramid paper honeycomb on a bottom plate; S20, providing a filling template, wherein the filling template is provided with through holes, and placing the filling template on the upper surface of the aramid paper honeycomb, with the through holes of the filling template corresponding to the pores of the aramid paper honeycomb; S30, adding filler to the pores of the aramid paper honeycomb through the filling template; S40, after the filler is added, removing the filling template, laying a panel on the upper surface of the aramid paper honeycomb to form a blank; and S50, molding the blank to obtain a microwave radiation control composite material.

[0031] A filling template is prepared. The filling template is carved according to a hollow pattern that matches the size of the honeycomb cells and has a certain periodicity. The filling template is used to fill the filler, which is simple and easy, efficient, suitable for mass production, and the filler is densely filled. The performance consistency of the composite material after filling is good.

[0032] Furthermore, in step S10, the cells of the aramid paper honeycomb are regular hexagons, and the side length of the regular hexagon is 4.5 to 35 mm.

[0033] It should be noted that the aramid paper honeycomb can be a blank aramid paper honeycomb or an absorbing aramid paper honeycomb, and can be selected according to the design requirements of microwave radiation regulation performance.

[0034] Specifically, the cell shape of the aramid paper honeycomb can be a regular quadrilateral or a regular hexagon. In this embodiment, the outer shape of the cells of the aramid paper honeycomb is a regular quadrilateral or a regular hexagon, and the side length of the cells is 4.5 - 35 mm. For example, it can be 4.5 mm, 10 mm, 25 mm or 35 mm. When the side length of the cells is within this range, the microwave radiation regulation performance of the obtained composite material is better.

[0035] Further, in step S20, the thickness of the filling template is 0.2 - 1 mm; and / or, the thickness of the aramid paper honeycomb is 5 - 100 mm.

[0036] In some embodiments, for the convenience of material selection, the thickness of the filling template can be 0.2 - 1 mm, for example, it can be 0.2 mm, 0.5 mm, 1 mm; in order to meet the requirements of microwave radiation regulation performance with different bandwidths and different regulation intensities on the basis of light weight and thinness, the thickness of the aramid paper honeycomb can be selected within the range of 5 - 100 mm, for example, it can be 5 mm, 50 mm, 85 mm, etc. <00000...​​​​​​​​​​​In some embodiments, during the process of filling the absorbing foam particles, after a filling template is used to fill a type of absorbing foam particles, the filling template is removed, and the unfilled cells in the aramid paper honeycomb can be left empty or filled with different types of absorbing foam particles, which can be selected according to the design requirements of the microwave radiation control performance.

[0041] Furthermore, the particle size of the wave-absorbing foam particles is 0.2-3 mm, for example, 0.2 mm, 1 mm, 2 mm or 3 mm.

[0042] It should be noted that spherical absorbing foam particles are mature products on the market. When they are used as fillers to fill the aramid paper honeycomb cells, spherical particles of the same type with different particle sizes can be selected for filling, or spherical particles of different types with different particle sizes can be selected for filling. Different particle sizes are more conducive to filling, making the filling gap smaller, and absorbing foam particles of different sizes can play a synergistic regulatory role on microwave radiation, so that the microwave radiation regulation performance is better.

[0043] Furthermore, in step S10, the bottom plate includes a carbon fiber plate, and the thickness of the carbon fiber plate is 0.2-1 mm; and / or, in step S40, the panel includes a fiberglass reinforced plastic plate, and the thickness of the fiberglass reinforced plastic plate is 0.2-1 mm.

[0044] It should be noted that the thickness of the bottom plate is 0.25 to 1 mm, for example, it can be 0.25 mm, 0.5 mm, or 1 mm. The thickness of the panel is 0.25 to 1 mm, for example, it can be 0.25 mm, 0.5 mm, or 1 mm. The panel protects the core material and allows microwaves to pass through, while the bottom plate protects the core material and reflects microwaves.

[0045] Furthermore, in step S50, the molding conditions are: the pressure is 0.2 MPa, the temperature is raised from 25-35°C to 80°C and then kept warm for 1 hour, then continued to rise to 120°C and kept warm for 2 hours, and finally dropped to 25-35°C.

[0046] Furthermore, epoxy structural adhesive films are provided on the upper and lower surfaces of the aramid paper honeycomb, respectively. The upper surface of the aramid paper honeycomb is bonded and fixed to the panel, and the lower surface of the aramid paper honeycomb is bonded and fixed to the bottom plate.

[0047] It should be noted that epoxy structural adhesive film is a commonly used adhesive with excellent adhesion and durability. It is composed of epoxy resin and a curing agent, forming a strong adhesive layer through a chemical reaction. Epoxy structural adhesive film is widely used in the construction, automotive, aerospace, and other fields. The epoxy structural adhesive film is used to bond the aramid paper honeycomb to the base plate and the front plate, ensuring a strong bond between the layers of the microwave radiation-modulating composite material.

[0048] In addition, the present invention also provides a microwave radiation control component for missile launch equipment. The microwave radiation control component for missile launch equipment is a microwave radiation control composite material prepared by the preparation method of the above-mentioned microwave radiation control composite material, and therefore also has all the beneficial effects of the above-mentioned microwave radiation control composite material.

[0049] In some embodiments, the microwave radiation control component of the missile launch equipment is used as an example and can be a component of other equipment that requires microwave radiation control.

[0050] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0051] Example 1

[0052] 1) On the flat mold, lay down the carbon fiber board with thickness of 0.5mm, epoxy structural adhesive film, and aramid paper honeycomb with thickness of 14mm, regular hexagonal cell shape and side length of 5.5mm in sequence, as shown in the attached Figure 4 As shown, a 7-cell filling template is carved from a 0.5mm thick aluminum plate (the hollowed-out portion is 7 adjacent honeycomb cells). The openings of the filling template are aligned with the honeycomb core cells. Polyurethane absorbing foam particles with particle sizes of 0.5mm, 1mm, and 3mm are mixed in a mass ratio of 1:1:1 and then filled into the exposed honeycomb cells through the filling template. After vibration compaction, the honeycomb cells filled with the absorbing foam particles form a repeated 7-cell periodic unit. Epoxy structural film and 0.5mm thick fiberglass plate are then laid to form a blank.

[0053] 2) The blank was molded under the following conditions: pressure of 0.2 MPa, temperature was raised from 30°C to 80°C and kept for 1 hour, then raised to 120°C and kept for 2 hours, and finally lowered to 30°C to obtain a microwave radiation controlled composite material.

[0054] Example 2

[0055] 1), Stack and lay a carbon fiber board with a thickness of 0.2 mm, an epoxy structural adhesive film, an aramid paper honeycomb with a thickness of 28 mm, a regular quadrilateral hole pattern and a side length of 20 mm, and a 4-hole filling template (the hollow part is 4 honeycomb hole patterns in a "field" shape) carved from a glass steel plate with a thickness of 0.2 mm on a flat mold in sequence. Align the template hole openings with the honeycomb core hole patterns, and use the filling template to fill the exposed honeycomb hole patterns with polymethacrylimide microwave-absorbing foam particles with particle sizes of 0.2 mm, 0.8 mm, and 2.5 mm in a mass ratio of 1:1:1. Compact it. The honeycomb hole patterns filled with microwave-absorbing foam particles form repeating 4-hole periodic units. Then continue to lay an epoxy structural adhesive film and a glass steel plate with a thickness of 0.3 mm to form a blank;

[0056] 2), Perform compression molding on the blank. The compression molding conditions are: the pressure is 0.2 MPa, the temperature is raised from 25 °C to 80 °C and then held for 1 h, then continue to be raised to 120 °C and held for 2 h, and finally lowered to 25 °C to obtain a microwave radiation regulation composite material.

[0057] Example 三 Replace "三" with "3" in English: Example 3

[0058] 1), Stack and lay a carbon fiber board with a thickness of 1 mm, an epoxy structural adhesive film, an aramid paper honeycomb with a thickness of 49 mm, a regular hexagon hole pattern and a side length of 28 mm, and a 3-hole filling template (the hollow part is 3 adjacent honeycomb hole patterns in a "pin" shape) carved from an aluminum plate with a thickness of 0.2 mm on a flat mold in sequence. Align the template hole openings with the honeycomb core hole patterns, and use the filling template to fill the exposed honeycomb hole patterns with polyurethane microwave-absorbing foam particles with particle sizes of 0.3 mm, 1 mm, and 2.5 mm in a mass ratio of 1:1:1. Compact it. The honeycomb hole patterns filled with microwave-absorbing foam particles form repeating 3-hole periodic units. Then continue to lay an epoxy structural adhesive film and a glass steel plate with a thickness of 1 mm to form a blank;

[0059] 2), Perform compression molding on the blank. The compression molding conditions are: the pressure is 0.2 MPa, the temperature is raised from 35 °C to 80 °C and then held for 1 h, then continue to be raised to 120 °C and held for 2 h, and finally lowered to 35 °C to obtain a microwave radiation regulation composite material.

[0060] Comparative Example 1

[0061] Method for preparing a microwave radiation regulation composite material using the existing technology:

[0062] 1), Use a plug with the same hole size as the honeycomb hole patterns of an aramid paper honeycomb with a thickness of 14 mm, a regular hexagon hole pattern and a side length of 5.5 mm to block some of the honeycomb hole patterns. The pattern formed by the blocked honeycomb hole patterns is the same as the non-hollow part pattern of the filling template in Example 1;

[0063] 2) Prepare the wave-absorbing foaming material in the foaming mold;

[0064] 3) placing the aramid paper honeycomb with partially blocked cells in a foaming mold for foaming;

[0065] 4) After the foaming is completed, the plug is removed to form a core material having the same absorbing foam pattern as in Example 1;

[0066] 5) Laying down a 0.5 mm thick carbon fiber plate, an epoxy structural adhesive film, the core material with the above-mentioned absorbing foam pattern, an epoxy structural adhesive film, and a 0.5 mm thick glass fiber reinforced plastic plate on a flat mold in sequence to form a blank;

[0067] 6) The blank was molded under the following conditions: pressure of 0.2 MPa, temperature was raised from 30°C to 80°C and kept for 1 hour, then continued to be raised to 120°C and kept for 2 hours, and finally lowered to 30°C to obtain a microwave radiation controlled composite material.

[0068] Performance Testing

[0069] Microwave radiation control performance stability

[0070] Arrange two workers to prepare a microwave radiation regulating composite material with a length and width of 2500 mm * 1000 mm respectively using the method of Example 1 and the prior art method of Comparative Example 1, and carry out small batch production. Samples of 10 microwave radiation regulating composite material flat plates with a length and width of 2500 mm * 1000 mm were taken from 10 batches, each batch containing 10 flat plates of microwave radiation regulating composite material with a length and width of 2500 mm * 1000 mm, and the microwave reflectivity was tested. The test results are as follows:

[0071] It takes 6 working hours to prepare one flat plate using the preparation method of Example 1. The maximum difference in microwave reflectivity of the 10 samples is 0.5 dB, and the performance stability is high.

[0072] However, it takes 13.5 working hours to prepare one flat plate using the prior art method of Comparative Example 1.

[0073] Ten batches of production, each containing 10 microwave radiation controlled composite material flat plates with a length and width of 2500mm*1000mm respectively, were selected as sampling objects. One sample was taken from each batch for microwave reflectivity test. The maximum difference in microwave reflectivity of the 10 samples was 3.9dB. The performance parameters fluctuated greatly and the stability was poor.

[0074] Controlling the performance parameters of composite materials by microwave radiation

[0075] The microwave radiation controllable performance of the microwave radiation controllable composite material prepared in the example was tested according to GJB 2038A-2011, and the performance parameters are shown in Table 1.

[0076] Table 1 Performance parameters of the microwave radiation controlled composite materials obtained in the examples and comparative examples

[0077]

[0078] As shown in Table 1, the microwave radiation controllable composite materials prepared in Example 1 and Comparative Example 1 have comparable microwave radiation controllable performance, but the preparation efficiency and performance stability of the prepared composite material in Example 1 are significantly higher than those in Comparative Example 1. Therefore, the preparation method of the present application is simple, efficient, suitable for mass production, and the prepared material has good performance consistency.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A method for preparing a composite material regulated by microwave radiation, characterized in that: The following steps are involved: S10, laying the aramid paper honeycomb on the bottom plate; S20, providing a filling template, wherein the filling template is provided with vias, and placing the filling template on the upper surface of the aramid paper honeycomb, with the vias of the filling template corresponding to the cells of the aramid paper honeycomb; S30, adding filler into the aramid paper honeycomb cells through the filling template; S40, after the filler is added, the filling template is removed, and a panel is laid on the upper surface of the aramid paper honeycomb to form a blank; S50, molding the blank to obtain a microwave radiation controlled composite material; Wherein, in step S30, the filler comprises spherical absorbing foam particles, and the absorbing foam particles comprise any one of polyurethane absorbing foam particles and polymethacrylimide foam particles; The filling template is carved according to a hollow pattern that matches the size of the honeycomb cells and has a certain periodicity; The wave-absorbing foam particles are particles formed by mechanical processing after the wave-absorbing foaming material is foamed in a free space.

2. The method for preparing a microwave radiation-controlled composite material according to claim 1, wherein: In step S10, the cells of the aramid paper honeycomb are regular hexagons, and the side length of the regular hexagon is 4.5-35 mm.

3. The method for preparing a microwave radiation controlled composite material according to claim 1, wherein: In step S20, The thickness of the filling template is 0.2-1 mm; and / or, The thickness of the aramid paper honeycomb is 5-100 mm.

4. The method for preparing a microwave radiation-controlled composite material according to claim 3, wherein: The particle size of the wave-absorbing foam particles is 0.2-3 mm.

5. The method for preparing a microwave radiation controlled composite material according to claim 1, wherein: In step S10, the bottom plate comprises a carbon fiber plate, and the thickness of the carbon fiber plate is 0.2-1 mm; and / or, In step S40, the panel includes a glass fiber reinforced plastic plate, and the thickness of the glass fiber reinforced plastic plate is 0.2-1 mm.

6. The method for preparing a microwave radiation controlled composite material according to claim 1, wherein: In step S50, the molding conditions are: the pressure is 0.2 MPa, the temperature is raised from 25-35°C to 80°C and then kept warm for 1 hour, then continued to rise to 120°C and kept warm for 2 hours, and finally dropped to 25-35°C.

7. The method for preparing a microwave radiation controlled composite material according to claim 1, wherein: Epoxy structural adhesive films are also provided on the upper and lower surfaces of the aramid paper honeycomb respectively, and the upper surface of the aramid paper honeycomb is bonded and fixed to the panel, and the lower surface of the aramid paper honeycomb is bonded and fixed to the bottom plate.

8. A microwave radiation control component for missile launch equipment, characterized in that: The invention comprises a microwave radiation controllable composite material prepared by the preparation method of the microwave radiation controllable composite material according to any one of claims 1 to 7.

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