A rubber-based aircraft access door and method of making the same

Abstract

A rubber-based aircraft hatch cover and a preparation method thereof, the preparation method comprising: S1: preparing wear-resistant layer wave-absorbing prepreg and structural layer wave-absorbing prepreg; wherein the wear-resistant layer wave-absorbing prepreg comprises a first base film and a first wave-absorbing adhesive film stacked with the first base film; the structural layer wave-absorbing prepreg comprises a second base film and a second wave-absorbing adhesive film stacked with the second base film; S2: stacking at least one layer of wear-resistant layer wave-absorbing prepreg and multiple layers of structural layer wave-absorbing prepreg to obtain an intermediate body; S3: placing the intermediate body in a hot press tank for heating and curing to obtain a laminate; S4: preparing a wave-absorbing silicone rubber layer; S5: coating a rubber treatment agent on the surface of the laminate, stacking the wave-absorbing silicone rubber layer with the laminate, and then performing vulcanization treatment to obtain the rubber-based aircraft hatch cover. The rubber-based aircraft hatch cover prepared by the method can always maintain good electromagnetic wave-absorbing performance, and has good wear resistance, fatigue resistance and other properties.

Description

Technical Field

[0001] This invention relates to the field of aircraft mouthpiece technology, and in particular to a rubber-based aircraft mouthpiece and its preparation method. Background Technology

[0002] Stealth aircraft are aircraft that utilize various technologies to reduce radar reflections, infrared radiation, and other signature information, making them difficult for enemy detection systems to detect. Among these technologies, the aircraft's access panels not only need to meet requirements for impact resistance, collision resistance, and abrasion resistance, but also for electromagnetic wave absorption.

[0003] Existing stealth aircraft canopies typically consist of a radar-absorbing coating applied to the surface of the canopy itself. The canopy itself is generally made of high-strength composite materials, giving it good structural strength. The radar-absorbing coating absorbs electromagnetic waves, thus achieving the canopy's electromagnetic wave absorption function. However, because the radar-absorbing coating is applied to the surface of the canopy itself, it is not wear-resistant and has relatively low hardness and rigidity. During aircraft operation, unavoidable mechanical movement or repeated disassembly can easily cause the radar-absorbing coating to detach from the canopy itself or wear down under external forces. This leads to a decrease in the electromagnetic wave absorption performance of the stealth aircraft canopy, requiring frequent maintenance or replacement. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a rubber-based aircraft mouthpiece. The aircraft mouthpiece prepared by this method can maintain good electromagnetic wave absorption performance and has good wear resistance and fatigue resistance.

[0005] This invention provides a method for preparing a rubber-based aircraft mouthpiece, comprising the following steps: S1: Preparation of wear-resistant layer microwave absorbing prepreg and structural layer microwave absorbing prepreg; The wear-resistant layer microwave absorbing prepreg includes a first base film and a first microwave absorbing adhesive film laminated with the first base film; the first microwave absorbing adhesive film comprises a first composition and a first microwave absorbing agent, wherein the mass of the first microwave absorbing agent accounts for 60%-80% of the total mass of the first microwave absorbing adhesive film; by mass parts, the first composition comprises 30-40 parts of first epoxy resin, 10-15 parts of first toughening agent, 1-5 parts of first accelerator, 15-30 parts of first modifier, 5-15 parts of first curing agent and 1-3 parts of wear-resistant agent; The structural layer microwave absorbing prepreg includes a second base film and a second microwave absorbing adhesive film laminated with the second base film; the components of the second microwave absorbing adhesive film include a second composition and a second microwave absorbing agent, wherein the mass of the second microwave absorbing agent accounts for 60%-80% of the total mass of the second microwave absorbing adhesive film; by mass parts, the second composition includes 30-40 parts of a second epoxy resin, 10-15 parts of a second toughening agent, 1-5 parts of a second accelerator, 15-30 parts of a second modifier and 5-15 parts of a second curing agent; S2: At least one layer of the wear-resistant microwave absorbing prepreg and multiple layers of the structural microwave absorbing prepreg are stacked to obtain an intermediate body; and the intermediate body is vacuumed to make it dense; wherein, multiple layers of the structural microwave absorbing prepreg are stacked sequentially, and the wear-resistant microwave absorbing prepreg is located on the outermost side of the intermediate body. S3: The intermediate is placed in an autoclave and heated to cure, thereby obtaining a laminate; wherein the curing temperature is 150℃-185℃, the curing time is 3-7 hours, and the curing pressure is 0.3-0.6MPa; S4: Prepare a microwave absorbing silicone rubber layer, wherein the components of the microwave absorbing silicone rubber layer include a third composition and a third microwave absorbing agent, wherein the mass of the third microwave absorbing agent accounts for 60%-80% of the total mass of the microwave absorbing silicone rubber layer; and the third composition comprises 40-50 parts of silicone rubber and 0.8-1 parts of vulcanizing agent by mass. S5: A rubber treatment agent is coated on the surface of the laminate away from the wear-resistant layer microwave-absorbing prepreg, and then dried to cure the rubber treatment agent; the microwave-absorbing silicone rubber layer is laminated with the side of the laminate coated with the rubber treatment agent, and then the microwave-absorbing silicone rubber layer and the laminate are vulcanized to obtain a rubber-based aircraft door cover; wherein the vulcanization temperature is 150℃~190℃, the vulcanization time is 10 minutes~60 minutes, and the vulcanization pressure is 10MPa~15MPa.

[0006] In one feasible embodiment, both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, the low-viscosity epoxy resins comprising one or more of bisphenol F type epoxy resin and dicyclopentadiene phenol epoxy resin; both the first toughening agent and the second toughening agent comprise one or more of polyetherimide, polystyrene, and polyimide; both the first accelerator and the second accelerator comprise KH-560 silane coupling agent; both the first modifier and the second modifier comprise one or more of dimethyldichlorosilane and MX-153 modifier; both the first curing agent and the second curing agent comprise one or more of diethylenetriamine, polyamide, N-aminoethylpiperazine, and 4,4'-diaminodiphenyl sulfone; and the wear-resistant agent comprises one or more of aramid micropowder and polyethylene micropowder.

[0007] In one feasible embodiment, the first, second, and third microwave absorbers each comprise one or more of iron powder, carbonyl iron powder, carbon powder, and alloy powder.

[0008] In one feasible embodiment, the first microwave absorber, the second microwave absorber, and the third microwave absorber are all Co-Ni-C coated carbonyl iron materials, and the preparation method of the Co-Ni-C coated carbonyl iron material includes the following steps: (1) Add carbonyl iron powder and polyvinylpyrrolidone to methanol and stir until homogeneous to obtain a suspension; then add cobalt nitrate hexahydrate and nickel nitrate hexahydrate to the suspension and stir until homogeneous to obtain solution A; And dissolve dimethylimidazole in methanol and stir until homogeneous to obtain solution B; The mass fractions of the carbonyl iron powder, the polyvinylpyrrolidone, the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate, and the dimethylimidazole are as follows: 100 parts of carbonyl iron powder, 5-15 parts of polyvinylpyrrolidone, 20-80 parts of cobalt nitrate hexahydrate, 20-80 parts of nickel nitrate hexahydrate, and 300-600 parts of dimethylimidazole. (2) Mix the solution A and the solution B and stir until homogeneous, then let stand for a period of time to obtain a mixture containing precipitate; (3) Separate the precipitate from the mixture, then wash the precipitate, and then dry the precipitate; (4) Under an inert gas atmosphere, the dried precipitate is heated to 400℃-700℃ at a heating rate of 2-8℃ / min, and then kept at the temperature for 1-5 hours to obtain the Co-Ni-C coated carbonyl iron material.

[0009] In one feasible embodiment, the first base film is a quartz fiber cloth, a glass fiber cloth, or a polyester cloth, and the second base film is a quartz fiber cloth, a glass fiber cloth, or a polyester cloth.

[0010] In one feasible manner, the method for preparing the wear-resistant layer microwave-absorbing prepreg includes the following steps: The first epoxy resin, the first toughening agent, the first accelerator, the first modifier, the first curing agent and the wear-resistant agent are mixed evenly, and then the first microwave absorbing agent is added and mixed evenly to obtain the first intermediate material; then the first intermediate material is rolled to obtain the first microwave absorbing film. The first microwave absorbing adhesive film is laminated with the first base film, and then rolled to combine the first microwave absorbing adhesive film and the first base film together, thus obtaining the wear-resistant layer microwave absorbing prepreg.

[0011] In one feasible manner, the method for preparing the structural layer microwave absorbing prepreg includes the following steps: The second epoxy resin, the second toughening agent, the second accelerator, the second modifier, and the second curing agent are mixed evenly, and then the second microwave absorbing agent is added and mixed evenly to obtain the second intermediate material; then the second intermediate material is rolled to obtain the second microwave absorbing film. The second microwave absorbing adhesive film is laminated with the second base film, and then rolled to combine the second microwave absorbing adhesive film and the second base film together, thus obtaining the wear-resistant layer microwave absorbing prepreg.

[0012] In one feasible embodiment, the first base film has a porous structure and is provided with a plurality of first mesh holes; in the wear-resistant layer microwave absorbing prepreg, the first microwave absorbing adhesive film is disposed on opposite sides of the first base film, and the first microwave absorbing adhesive films on opposite sides of the first base film are connected through the first mesh holes. And / or, the second base film has a porous structure, and the second base film is provided with a plurality of second mesh holes; in the structural layer microwave absorbing prepreg, the second microwave absorbing adhesive film is disposed on opposite sides of the second base film, and the second microwave absorbing adhesive films on opposite sides of the second base film are connected through the second mesh holes.

[0013] In one feasible embodiment, the thickness of the first base film is 0.05mm-0.2mm, the thickness of the first microwave absorbing adhesive film is 0.05mm-0.1mm, the thickness of the second base film is 0.05mm-0.2mm, the thickness of the second microwave absorbing adhesive film is 0.05mm-0.1mm, the thickness of the intermediate is 1.2mm-6mm, and the thickness of the microwave absorbing silicone rubber layer is 0.3±0.1mm.

[0014] The present invention also provides a rubber-based aircraft mouthpiece, which is manufactured using the above-described method for preparing a rubber-based aircraft mouthpiece.

[0015] The present invention provides a method for preparing a rubber-based aircraft hatch, which involves laminating and co-curing a wear-resistant layer microwave-absorbing prepreg and a structural layer microwave-absorbing prepreg to obtain a laminate, and then laminating a microwave-absorbing silicone rubber layer with the laminate and co-curing to obtain the rubber-based aircraft hatch. On the one hand, because the wear-resistant layer microwave-absorbing prepreg, the structural layer microwave-absorbing prepreg, and the microwave-absorbing silicone rubber layer all contain microwave-absorbing agents, the rubber-based aircraft hatch has excellent electromagnetic wave absorption performance. Moreover, compared to the existing method of covering the surface of the hatch body with microwave-absorbing coating, this solution, because the microwave-absorbing agent is contained in each wear-resistant layer, structural layer, and rubber layer, avoids problems such as microwave-absorbing coating peeling or wear, allowing the rubber-based aircraft hatch to maintain good electromagnetic wave absorption performance at all times. On the other hand, because wear-resistant agents are added to the wear-resistant layer microwave-absorbing prepreg, the wear-resistant layer has good... The wear-resistant properties are excellent, and because the wear-resistant layer microwave-absorbing prepreg is located on the outermost side of the intermediate body, that is, the wear-resistant layer is located on the outer surface of the rubber-based aircraft hatch, the outer surface of the rubber-based aircraft hatch has good wear resistance. Furthermore, since the wear-resistant layer microwave-absorbing prepreg and the structural layer microwave-absorbing prepreg use the same resin system, the interlayer thermal expansion coefficients of the two are matched, and the interlayer bonding force is high, with small co-curing deformation. At the same time, the microwave-absorbing silicone rubber layer and the laminate are co-vulcanized and have high bonding force, resulting in high structural strength of the prepared rubber-based aircraft hatch. It has good wear resistance, fatigue resistance and other properties, and is not easily damaged by external forces. This can reduce the maintenance or replacement of the rubber-based aircraft hatch, and even achieve maintenance-free operation of the rubber-based aircraft hatch during its service life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional schematic diagram of a rubber-based aircraft mouthpiece in an embodiment of the present invention.

[0018] Figure 2 This is a cross-sectional schematic diagram of the wear-resistant layer microwave-absorbing prepreg in an embodiment of the present invention.

[0019] Figure 3 This is a cross-sectional schematic diagram of the microwave absorbing prepreg in the structural layer of this invention.

[0020] Figure 4 This is a schematic diagram of the electromagnetic wave reflectivity test results of the rubber-based aircraft mouthpiece in Embodiment 1 of the present invention.

[0021] Figure 5This is a schematic diagram of the electromagnetic wave reflectivity test results of the rubber-based aircraft mouthpiece in Embodiment 2 of the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. The terms "first," "second," "third," "fourth," etc. (if present) in the specification and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] like Figures 1 to 3 As shown, this embodiment of the invention provides a method for preparing a rubber-based aircraft mouthpiece, comprising the following steps: S1: Prepare the wear-resistant layer microwave absorbing prepreg 10 and the structural layer microwave absorbing prepreg 20; The wear-resistant microwave absorbing prepreg 10 includes a first base film 11 and a first microwave absorbing adhesive film 12 laminated with the first base film 11 (specifically, the first microwave absorbing adhesive film 12 is laminated on the first base film 11 along its thickness direction). The first microwave absorbing adhesive film 12 comprises a first composition and a first microwave absorbing agent, wherein the first microwave absorbing agent accounts for 60%-80% of the total mass of the first microwave absorbing adhesive film 12, and the remainder is the first composition. By mass parts, the first composition comprises 30-40 parts of a first epoxy resin, 10-15 parts of a first toughening agent, 1-5 parts of a first accelerator, 15-30 parts of a first modifier, 5-15 parts of a first curing agent, and 1-3 parts of a wear-resistant agent.

[0024] The structural layer microwave absorbing prepreg 20 includes a second base film 21 and a second microwave absorbing adhesive film 22 laminated with the second base film 21 (specifically, the second microwave absorbing adhesive film 22 is laminated on the second base film 21 along its thickness direction). The second microwave absorbing adhesive film 22 comprises a second composition and a second microwave absorbing agent, with the second microwave absorbing agent accounting for 60%-80% of the total mass of the second microwave absorbing adhesive film 22, and the remainder being the second composition. By mass parts, the second composition comprises 30-40 parts of a second epoxy resin, 10-15 parts of a second toughening agent, 1-5 parts of a second accelerator, 15-30 parts of a second modifier, and 5-15 parts of a second curing agent. The main difference between the second composition and the first composition is that the second composition does not include abrasion-resistant agents.

[0025] S2: At least one layer of wear-resistant microwave absorbing prepreg 10 and multi-layer structural microwave absorbing prepreg 20 are stacked to obtain an intermediate body; and the intermediate body is vacuumed to make it dense; wherein, the multi-layer structural microwave absorbing prepreg 20 is stacked in sequence, and the wear-resistant microwave absorbing prepreg 10 is located on the outermost side of the intermediate body. S3: The intermediate is placed in an autoclave for heating and curing to obtain the laminate; wherein the curing temperature is 150℃-185℃, the curing time is 3-7 hours, and the curing pressure is 0.3-0.6MPa. The wear-resistant microwave-absorbing prepreg 10 in the intermediate forms wear-resistant layer 1 after curing, and the structural layer microwave-absorbing prepreg 20 in the intermediate forms structural layer 2 after curing; that is, the multi-layer structural layer microwave-absorbing prepreg 20 forms a multi-layered, sequentially stacked structural layer 2 after curing. Figure 1 (The diagram shows 10 floors).

[0026] S4: Prepare a microwave-absorbing silicone rubber layer (i.e., a microwave-absorbing silicone rubber raw rubber layer). The microwave-absorbing silicone rubber layer comprises a third composition and a third microwave-absorbing agent. The mass of the third microwave-absorbing agent accounts for 60%-80% of the total mass of the microwave-absorbing silicone rubber layer. By mass, the third composition comprises 40-50 parts of silicone rubber and 0.8-1 parts of vulcanizing agent. S5: A rubber treatment agent is coated on the surface of the laminate away from the wear-resistant microwave-absorbing prepreg, and then dried to cure the rubber treatment agent. The microwave-absorbing silicone rubber layer is then laminated to the side of the laminate coated with the rubber treatment agent (i.e., the microwave-absorbing silicone rubber layer is located on the side of the laminate away from the wear-resistant microwave-absorbing prepreg), and then the microwave-absorbing silicone rubber layer and the laminate are vulcanized to obtain a rubber-based aircraft door cover. The vulcanization temperature is 150℃~190℃, the vulcanization time is 10 minutes~60 minutes, and the vulcanization pressure is 10MPa~15MPa. After vulcanization, the microwave-absorbing silicone rubber layer vulcanizes to form rubber layer 3.

[0027] In step S1 above, the toughening agent (including the first toughening agent and the second toughening agent) is used to reduce the brittleness of the resin matrix and improve its impact resistance and toughness; the modifier (including the first modifier and the second modifier) ​​is used to improve the impact resistance, wear resistance and other properties of the resin matrix; the curing agent (including the first curing agent and the second curing agent) is used to promote the cross-linking and curing reaction of the epoxy resin, so that the epoxy resin can be cured quickly after heating; the accelerator (including the first accelerator and the second accelerator) mainly promotes the dissolution of the curing agent in the epoxy resin and increases the curing reaction rate; and the wear-resistant agent is mainly used to improve the wear resistance of the material.

[0028] In step S2 above, when the wear-resistant microwave absorbing prepreg 10 is a single layer, this single layer of wear-resistant microwave absorbing prepreg 10 is located on the outermost side of the intermediate body; when the wear-resistant microwave absorbing prepreg 10 is multi-layered (generally no more than three layers), the multi-layered wear-resistant microwave absorbing prepreg 10 is stacked sequentially and located on the outermost side of the intermediate body. Generally, setting one layer of wear-resistant microwave absorbing prepreg 10 in the intermediate body is sufficient to meet the wear resistance requirements.

[0029] In step S2 above, vacuuming the intermediate is to remove air bubbles (including air bubbles in the wear-resistant layer microwave absorbing prepreg 10, air bubbles in the structural layer microwave absorbing prepreg 20, and air bubbles between layers) from the intermediate, thereby making the intermediate denser.

[0030] Specifically, the vacuuming process can be as follows: Based on the stacking order of the prepregs, first stack 2-3 layers of prepreg (including the wear-resistant layer microwave-absorbing prepreg 10 and / or the structural layer microwave-absorbing prepreg 20), then vacuum it once; then stack another 2-3 layers of prepreg, and vacuum it again; and so on, until all prepreg stacking and vacuuming operations are completed. The vacuuming pressure can be 0.1 MPa each time, and the vacuuming time can be 10-15 minutes each time. This operation can better remove air bubbles from the intermediate (because the intermediate has a multi-layered structure, it is more difficult to remove air bubbles after the intermediate is stacked), improving the compactness of the intermediate and thus increasing the structural strength of the rubber-based aircraft cap. Of course, in other embodiments, the intermediate can also be vacuumed after all the prepregs are stacked.

[0031] In step S5 above, by coating the surface of the laminate with a rubber treatment agent, the rubber treatment agent can improve the adhesion between the microwave absorbing silicone rubber layer and the laminate.

[0032] The method for preparing a rubber-based aircraft hatch provided by this invention involves laminating a wear-resistant layer microwave-absorbing prepreg 10 and a structural layer microwave-absorbing prepreg 20 together and curing them to obtain a laminate. Then, a microwave-absorbing silicone rubber layer is laminated with the laminate and co-cured to obtain the rubber-based aircraft hatch. On one hand, since the wear-resistant layer microwave-absorbing prepreg 10, the structural layer microwave-absorbing prepreg 20, and the microwave-absorbing silicone rubber layer all contain microwave-absorbing agents, the rubber-based aircraft hatch has excellent electromagnetic wave absorption performance. Furthermore, compared to the existing method of covering the surface of the hatch body with a microwave-absorbing coating, this solution, because the microwave-absorbing agent is contained within each wear-resistant layer 1, structural layer 2, and rubber layer 3, avoids problems such as coating peeling or wear, ensuring that the rubber-based aircraft hatch maintains excellent electromagnetic wave absorption performance. On the other hand, since the wear-resistant layer microwave-absorbing prepreg 10 contains a wear-resistant agent, the wear-resistant layer 1 has excellent wear resistance. Moreover, because the wear-resistant layer microwave-absorbing prepreg 10 is... The outermost layer of the intermediate, namely the wear-resistant layer 1, is located on the outer surface of the rubber-based aircraft hatch, thus giving the outer surface of the rubber-based aircraft hatch good wear resistance (since the structural layer 2 is located inside the rubber-based aircraft hatch, it will not rub against the outside, so no wear-resistant agent needs to be added to the structural layer 2); on the other hand, since the wear-resistant layer microwave-absorbing prepreg 10 and the structural layer microwave-absorbing prepreg 20 use the same resin system, the interlayer thermal expansion coefficients of the wear-resistant layer microwave-absorbing prepreg 10 and the structural layer microwave-absorbing prepreg 20 are matched, and the interlayer bonding force is high, with small co-curing deformation. At the same time, the microwave-absorbing silicone rubber layer and the laminate are co-vulcanized and have high bonding force, resulting in high structural strength of the prepared rubber-based aircraft hatch, with good wear resistance, fatigue resistance and other properties, and it is not easily damaged by external forces, which can reduce the maintenance or replacement of the rubber-based aircraft hatch, and even achieve maintenance-free operation of the rubber-based aircraft hatch during its service life.

[0033] In one embodiment, in step S1 above, both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, including one or more of bisphenol F type epoxy resin and dicyclopentadiene phenol epoxy resin. Because low-viscosity epoxy resins have good flowability, using them facilitates the uniform mixing of the components in the first microwave absorbing film 12 and the second microwave absorbing film 22, and also facilitates the molding of the first microwave absorbing film 12 and the second microwave absorbing film 22, making processing easier.

[0034] In one embodiment, in step S1 above, the first toughening agent includes one or more of polyetherimide (PEI), polystyrene (PS), and polyimide (PI); the first accelerator includes KH-560 silane coupling agent; the first modifier includes one or more of dimethyldichlorosilane (DDS) and MX-153 modifier; the first curing agent includes one or more of diethylenetriamine, polyamide, N-aminoethylpiperazine, and 4,4'-diaminodiphenyl sulfone; and the wear-resistant agent includes one or more of aramid micropowder (specifically, interface-modified micronized aramid) and polyethylene micropowder (specifically, interface-modified ultra-high molecular weight polyethylene micropowder).

[0035] The second toughening agent includes one or more of polyetherimide, polystyrene, and polyimide; the second accelerator includes KH-560 silane coupling agent; the second modifier includes one or more of dimethyldichlorosilane and MX-153 modifier; and the second curing agent includes one or more of diethylenetriamine, polyamide, N-aminoethylpiperazine, and 4,4'-diaminodiphenyl sulfone.

[0036] In one embodiment, in step S1 above, the mass fraction of the first epoxy resin can be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, or 40 parts, or any combination thereof. The mass fraction of the first toughening agent can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, or any combination thereof. The mass fraction of the first accelerator can be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, or any combination thereof. The mass fraction of the first modifier can be 15 parts, 18 parts, 20 parts, 25 parts, or 30 parts, or any combination thereof. The mass fraction of the first curing agent can be 5 parts, 7 parts, 10 parts, 12 parts, or 15 parts, or any combination thereof. The wear-resistant agent can be in parts by weight of 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts, or any combination of the above parts by weight.

[0037] The second epoxy resin can be in the following weight ranges: 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, or 40 parts, or any combination thereof. The second toughening agent can be in the following weight ranges: 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, or any combination thereof. The second accelerator can be in the following weight ranges: 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, or any combination thereof. The second modifier can be in the following weight ranges: 15 parts, 18 parts, 20 parts, 25 parts, or 30 parts, or any combination thereof. The second curing agent can be in the following weight ranges: 5 parts, 7 parts, 10 parts, 12 parts, or 15 parts, or any combination thereof.

[0038] In one embodiment, in step S1 above, the first epoxy resin, first toughening agent, first accelerator, first modifier, and first curing agent in the first composition are the same materials as the second epoxy resin, second toughening agent, second accelerator, second modifier, and second curing agent in the second composition. The first epoxy resin, first toughening agent, first accelerator, first modifier, and first curing agent in the first composition have the same mass fraction as the second epoxy resin, second toughening agent, second accelerator, second modifier, and second curing agent in the second composition. The only difference between the two is that the second composition does not include a wear-resistant agent, thereby making the components of the wear-resistant layer microwave-absorbing prepreg 10 and the structural layer microwave-absorbing prepreg 20 more similar, so that the two have better interlayer bonding performance and more similar interlayer thermal expansion coefficients.

[0039] In one embodiment, in steps S1 and S4 above, the first microwave absorbing agent includes one or more of iron powder, carbonyl iron powder, carbon powder, and alloy powder. The second microwave absorbing agent includes one or more of iron powder, carbonyl iron powder, carbon powder, and alloy powder. The third microwave absorbing agent includes one or more of iron powder, carbonyl iron powder, carbon powder, and alloy powder.

[0040] As another implementation, in step S1 above, the first absorbing agent, the second absorbing agent, and the third absorbing agent are all Co-Ni-C coated carbonyl iron materials. The Co-Ni-C coated carbonyl iron material is a Co-Ni-C coating layer covering the surface of carbonyl iron particles. The Co-Ni-C coating layer is a MOF (metal-organic framework) structure, that is, the Co-Ni-C coating layer is CoNi-MOF, which means that the Co-Ni-C coating layer is a porous metal framework structure constructed by the coordination assembly of Co metal particles, Ni metal particles, and C particles.

[0041] Specifically, iron carbonyl is one of the more common microwave absorbing agents, and it has attracted widespread attention in the field of microwave absorption due to its advantages of high magnetic permeability, high saturation magnetization, and low cost. However, iron carbonyl has problems such as low dielectric loss, poor oxidation resistance, and excessive density, which to some extent limit its application in microwave absorption. To solve this problem, this application utilizes CoNi-MOF to coat iron carbonyl. CoNi-MOF can improve the ability of iron carbonyl to absorb electromagnetic waves, and the coating of iron carbonyl with CoNi-MOF can improve its oxidation resistance. At the same time, since CoNi-MOF has a porous structure, its density is low, thereby reducing the density of the iron carbonyl absorber. Therefore, Co-Ni-C coated iron carbonyl material has advantages such as good microwave absorption performance, good oxidation resistance, and low density.

[0042] As one implementation method, this embodiment synthesizes CoNi-MOF in situ on the surface of carbonyl iron via electrostatic self-assembly and heat treatment. The preparation method of this Co-Ni-C coated carbonyl iron material includes the following steps: (1) Add carbonyl iron powder and polyvinylpyrrolidone to methanol (the amount of methanol is appropriate) and stir evenly to obtain a suspension; then add cobalt nitrate hexahydrate (i.e., Co(NO3)2·6H2O) and nickel nitrate hexahydrate (i.e., Ni(NO3)2·6H2O) to the obtained suspension and stir evenly to obtain solution A; And dissolve dimethylimidazole in methanol (the amount of methanol is appropriate), and stir well to obtain solution B; The mass fractions of carbonyl iron powder, polyvinylpyrrolidone, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and dimethylimidazole are as follows: 100 parts of carbonyl iron powder, 5-15 parts of polyvinylpyrrolidone, 20-80 parts of cobalt nitrate hexahydrate, 20-80 parts of nickel nitrate hexahydrate, and 300-600 parts of dimethylimidazole; that is, the mass ratio of carbonyl iron powder, polyvinylpyrrolidone, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and dimethylimidazole is 100:(5-15):(20-80):(20-80):(300-600).

[0043] (2) Mix solution A and solution B and stir until homogeneous, then let stand for a period of time to obtain a mixture containing precipitate; (3) Separate the precipitate from the mixture, then wash the precipitate and then dry it; (4) Under an inert gas atmosphere, the dried precipitate is heated to 400℃-700℃ at a heating rate of 2-8℃ / min, and then kept at the temperature for 1-5 hours to obtain Co-Ni-C coated carbonyl iron material.

[0044] In step (1) above, polyvinylpyrrolidone is equivalent to a surfactant. After carbonyl iron powder and polyvinylpyrrolidone are added to methanol and mixed evenly, polyvinylpyrrolidone will coat the surface of carbonyl iron powder. After cobalt nitrate hexahydrate and nickel nitrate hexahydrate are added to the suspension and mixed evenly, polyvinylpyrrolidone will adsorb Co ions and Ni ions, so that Co ions and Ni ions are uniformly distributed on the surface of carbonyl iron powder in advance.

[0045] In step (2) above, dimethylimidazole in solution B is equivalent to a ligand. During the standing process after mixing and stirring solution A and solution B, dimethylimidazole will coordinate with Co ions and Ni ions to form a complex. The precipitate in step (2) is carbonyl iron powder with the complex coated on its surface.

[0046] In step (3) above, the precipitate is washed to remove uncoordinated polyvinylpyrrolidone, cobalt nitrate hexahydrate, nickel nitrate hexahydrate and dimethylimidazole, so as to obtain carbonyl iron powder with the complex coated on the surface.

[0047] In step (4) above, after heating the dried precipitate, the dimethylimidazolium in the complex undergoes a redox reaction to obtain elemental carbon (i.e., dimethylimidazolium provides the carbon source), i.e., dimethylimidazolium graphitization; the elemental carbon then reduces Co ions and Ni ions to obtain Co metal particles and Ni metal particles, thereby forming a Co-Ni-C porous metal framework structure, i.e., CoNi-MOF.

[0048] In one implementation, in step (1) above, the carbonyl iron powder is pre-cleaned by ultrasonic cleaning to remove impurities from the surface of the carbonyl iron powder. The specific steps can be as follows: a certain amount of carbonyl iron powder is placed in anhydrous ethanol and ultrasonically cleaned for a period of time (e.g., 30 min); then the carbonyl iron powder in the anhydrous ethanol is separated by a magnet and then dried (e.g., dried at 70°C for 4 h).

[0049] As one implementation method, the specific operation steps of step (2) above can be: slowly mix solution A and solution B, stir for 1 hour and then let stand for 24 hours.

[0050] As one implementation method, in step (3) above, the precipitate can be washed with methanol or anhydrous ethanol, and then the precipitate can be dried at 70°C for 4 hours.

[0051] As one implementation method, in step (4) above, the inert gas atmosphere can be an inert gas atmosphere such as helium or argon, the purpose of which is to prevent the product from oxidizing.

[0052] In one embodiment, in step (1) above, the mass fraction of polyvinylpyrrolidone can be 5 parts, 8 parts, 10 parts, 12 parts, or 15 parts, or any combination thereof. The mass fraction of cobalt nitrate hexahydrate can be 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, or 80 parts, or any combination thereof. The mass fraction of nickel nitrate hexahydrate can be 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, or 80 parts, or any combination thereof. The mass fraction of dimethylimidazole can be 300 parts, 350 parts, 400 parts, 450 parts, 500 parts, 550 parts, or 600 parts, or any combination thereof.

[0053] In one implementation, in step (4) above, the heating rate can be 2℃ / min, 4℃ / min, 6℃ / min, or 8℃ / min, or any combination of the above values. The heating temperature can be 400℃, 500℃, 600℃, or 700℃, or any combination of the above temperatures. The holding time can be 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours, or any combination of the above times.

[0054] In one implementation, in steps S1 and S4 above, the mass of the first absorbing agent can account for 60%, 65%, 70%, 75%, or 80% of the total mass of the first absorbing film 12, or any combination thereof. The mass of the second absorbing agent can account for 60%, 65%, 70%, 75%, or 80% of the total mass of the second absorbing film 22, or any combination thereof. The mass of the third absorbing agent accounts for 60%, 65%, 70%, 75%, or 80% of the total mass of the absorbing silicone rubber layer, or any combination thereof.

[0055] As one implementation method, the preparation method of the wear-resistant layer microwave absorbing prepreg 10 in step S1 above includes the following steps: The first epoxy resin, first toughening agent, first accelerator, first modifier, first curing agent, and wear-resistant agent are mixed evenly, and then the first microwave absorbing agent is added and mixed evenly (since it is difficult to mix the first composition evenly after adding the first microwave absorbing agent, the components in the first composition are mixed evenly first, and then the first microwave absorbing agent is added), to obtain the first intermediate material; then the first intermediate material is rolled to obtain the first microwave absorbing film 12; The first microwave absorbing film 12 and the first base film 11 are laminated together, and then rolled to combine the first microwave absorbing film 12 and the first base film 11 together, thus obtaining the wear-resistant microwave absorbing prepreg 10.

[0056] As one implementation method, the preparation method of the structural layer microwave absorbing prepreg 20 in step S1 above includes the following steps: The second epoxy resin, the second toughening agent, the second accelerator, the second modifier, and the second curing agent are mixed evenly, and then the second microwave absorbing agent is added and mixed evenly to obtain the second intermediate material; then the second intermediate material is rolled to obtain the second microwave absorbing film 22. The second microwave absorbing adhesive film 22 and the second base film 21 are laminated together, and then rolled to combine the second microwave absorbing adhesive film 22 and the second base film 21 together, thus obtaining the wear-resistant layer microwave absorbing prepreg 10.

[0057] like Figure 2 and Figure 3 As shown, in one embodiment, in step S1 above, the first base film 11 has a porous structure and is provided with a plurality of first mesh holes 111, which penetrate the first base film 11 along its thickness direction. In each wear-resistant layer microwave-absorbing prepreg 10, a first microwave-absorbing adhesive film 12 is disposed on opposite sides of the first base film 11, and the first microwave-absorbing adhesive films 12 on opposite sides of the first base film 11 are connected through the first mesh holes 111. That is, the first microwave-absorbing adhesive film 12 is not only disposed on the surface of the first base film 11, but also fills the first mesh holes 111 of the first base film 11, so that the first microwave-absorbing adhesive films 12 on both sides can be connected through the first microwave-absorbing adhesive films 12 in the first mesh holes 111, reducing the risk of the first microwave-absorbing adhesive film 12 detaching from the first base film 11 and improving the structural strength of the wear-resistant layer 1. During manufacturing, the first microwave-absorbing adhesive film 12 can be stacked on both sides of the first base film 11, and then rolled to embed the first microwave-absorbing adhesive film 12 into the first mesh holes 111.

[0058] The second base film 21 has a porous structure with multiple second mesh openings 211 extending through it along its thickness. In each structural layer's microwave-absorbing prepreg 20, a second microwave-absorbing adhesive film 22 is disposed on opposite sides of the second base film 21, connected through the second mesh openings 211. That is, the second microwave-absorbing adhesive film 22 is not only disposed on the surface of the second base film 21 but also fills the second mesh openings 211, allowing the second microwave-absorbing adhesive films 22 on both sides to be connected through the mesh openings 211. This reduces the risk of the second microwave-absorbing adhesive film 22 detaching from the second base film 21 and improves the structural strength of the structural layer 2. During manufacturing, the second microwave-absorbing adhesive film 22 can be stacked on both sides of the second base film 21 and then rolled to embed the second microwave-absorbing adhesive film 22 into the second mesh openings 211.

[0059] In one embodiment, the mesh count of the first mesh 111 on the first base film 11 can be 20-500 mesh. The mesh count of the second mesh 211 on the second base film 21 can be 20-500 mesh.

[0060] In one embodiment, in step S1 above, the first base film 11 is made of quartz fiber cloth, glass fiber cloth, or polyester cloth, and the second base film 21 is made of quartz fiber cloth, glass fiber cloth, or polyester cloth. The materials of the first base film 11 and the second base film 21 can be the same or different.

[0061] In one embodiment, the thickness of the first base film 11 is 0.05mm-0.2mm, and the thickness of the first absorbing adhesive film 12 is 0.05mm-0.1mm. The thickness of the second base film 21 is 0.05mm-0.2mm, and the thickness of the second absorbing adhesive film 22 is 0.05mm-0.1mm. The thickness of the intermediate is 1.2mm-6mm. The thickness of the absorbing silicone rubber layer is 0.3±0.1mm.

[0062] In one implementation, in step S2 above, the number of structural layer microwave absorbing prepreg 20 layers in the intermediate body is not less than 8 layers, or not less than 10 layers, for example, 8-20 layers. Specifically, in step S2 above, a layer of wear-resistant microwave absorbing prepreg 10 can be laid on the mold first, and then multiple layers of structural layer microwave absorbing prepreg 20 can be laid until the thickness reaches 1.2mm-6mm.

[0063] In one implementation, in step S3 above, the curing temperature can be 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, or 185℃, or any combination thereof. The curing time can be 3 hours, 4 hours, 5 hours, 6 hours, or 7 hours, or any combination thereof. The curing pressure can be 0.3MPa, 0.4MPa, 0.5MPa, or 0.6MPa, or any combination thereof.

[0064] In one implementation, in step S4 above, the silicone rubber can specifically be methyl vinyl silicone rubber, methyl phenyl silicone rubber, fluorosilicone rubber, nitrile silicone rubber, etc., and the vulcanizing agent can be bis-25 vulcanizing agent, DCP (diisopropylbenzene peroxide), etc. The mass fraction of the silicone rubber can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, or 50 parts, or any combination thereof. The mass fraction of the vulcanizing agent can be 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 part, or any combination thereof.

[0065] As one implementation method, the preparation method of the microwave absorbing silicone rubber layer in step S4 above includes the following steps: Silicone rubber, vulcanizing agent and third microwave absorbing agent are mixed evenly to obtain third intermediate material; then the third intermediate material is rolled to obtain microwave absorbing silicone rubber layer.

[0066] In one implementation method, the rubber treatment agent in step S5 above can be Chemlock 608, Rohm and Haas FLB315, etc. The drying temperature can be 80°C, and the drying time can be 10-30 minutes, as long as the solvent in the rubber treatment agent evaporates and the rubber treatment agent cures.

[0067] In one implementation, in step S5 above, the vulcanization temperature can be 150°C, 160°C, 170°C, 180°C, 190°C, etc., or any combination of the above temperatures; the vulcanization time can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, etc., or any combination of the above times; the vulcanization pressure can be 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, etc., or any combination of the above pressures.

[0068] This invention also provides a rubber-based aircraft mouthpiece, which is manufactured using the rubber-based aircraft mouthpiece preparation method described above.

[0069] Example 1 The manufacturing process of rubber-based aircraft mouthpieces includes the following steps: 1. Preparation of the wear-resistant microwave absorbing prepreg: 30 parts of bisphenol F type epoxy resin, 10 parts of polyetherimide, 1 part of KH-560 silane coupling agent, 15 parts of dimethyldichlorosilane, 5 parts of diethylenetriamine, and 1 part of aramid micro powder are added to a mixer and mixed evenly. Then, 60% by mass of carbonyl iron powder (i.e., the mass of carbonyl iron powder accounts for 60% of the total mass of the first microwave absorbing film, and other components account for 40% of the total mass of the first microwave absorbing film) is added, and the mixture is then mixed evenly in a mixer to obtain the first intermediate material. The first intermediate material is rolled using a roller press to obtain the first microwave absorbing film. Then, the first microwave absorbing film is stacked on both sides of 0.1mm quartz fiber cloth and rolled using a double-sided pressing method to obtain the wear-resistant microwave absorbing prepreg.

[0070] 2. Preparation of the structural layer microwave absorbing prepreg: 30 parts of bisphenol F type epoxy resin, 10 parts of polyetherimide, 1 part of KH-560 silane coupling agent, 15 parts of dimethyldichlorosilane, and 5 parts of diethylenetriamine are added to a mixer and mixed evenly. Then, 60% by mass of carbonyl iron powder (i.e., the mass of carbonyl iron powder accounts for 60% of the total mass of the second microwave absorbing film, and other components account for 40% of the total mass of the second microwave absorbing film) is added, and the mixture is then mixed evenly in a mixer to obtain the second intermediate material. The second intermediate material is rolled using a roller press to obtain the second microwave absorbing film. Then, the second microwave absorbing film is stacked on both sides of a 0.1mm quartz fiber cloth and rolled using a double-sided pressing method to obtain the structural layer microwave absorbing prepreg.

[0071] 3. Stack one layer of wear-resistant microwave absorbing prepreg and 19 layers of structural microwave absorbing prepreg, and then vacuum process them to obtain an intermediate.

[0072] 4. The intermediate is placed in an autoclave for heating and curing to obtain the laminate; wherein the curing temperature is 160℃, the curing time is 4 hours, and the curing pressure is 0.5MPa.

[0073] 5. Preparation of the microwave-absorbing silicone rubber layer: 45 parts of methyl vinyl silicone rubber and 0.8 parts of bis-25 vulcanizing agent are added to a mixer and mixed evenly. Then, 60% by mass of carbonyl iron powder is added (i.e., the mass of carbonyl iron powder accounts for 60% of the total mass of the microwave-absorbing silicone rubber layer, and other components account for 40% of the total mass of the microwave-absorbing silicone rubber layer). The mixture is then further mixed evenly in a mixer to obtain the third intermediate material. This third intermediate material is then rolled using a roller press to obtain the microwave-absorbing silicone rubber layer, with a thickness of 0.3 mm.

[0074] 6. Apply a rubber treatment agent to the surface of the laminate away from the wear-resistant layer of the microwave-absorbing prepreg, and dry it at 80°C for 20 minutes to allow the rubber treatment agent to dry and cure. Lay the microwave-absorbing silicone rubber layer with the side of the laminate coated with the rubber treatment agent, and then vulcanize the microwave-absorbing silicone rubber layer and the laminate together to obtain a rubber-based aircraft door cover; wherein the vulcanization temperature is 160°C, the vulcanization time is 20 minutes, and the vulcanization pressure is 15 MPa.

[0075] The structural strength, wear resistance, fatigue resistance, and electromagnetic wave absorption performance of the aforementioned rubber-based aircraft hatch were tested. The test results are shown in the table below. Figure 4 As shown.

[0076] (1) Structural strength test: The table above shows the data obtained by testing the short beam strength of five rubber-based aircraft hatches (samples 1-5) prepared using the same method. As can be seen from the table, the average short beam strength of the rubber-based aircraft hatches reaches 84.6 MPa, demonstrating that the rubber-based aircraft hatches have good structural strength, good interlayer bonding of the material, and are not prone to delamination between prepregs.

[0077] (2) Wear resistance and fatigue resistance test: The rubber-based aircraft cover was subjected to bending test using a bending machine; after 110,000 bending cycles, the rubber-based aircraft cover did not break and there was no obvious resin shedding on the surface, proving that the material has good wear resistance and fatigue resistance.

[0078] (3) Electromagnetic wave absorption performance test: Electromagnetic wave reflectivity test (i.e., absorption test) was performed on the rubber-based aircraft cover. Specific test methods can be found in patents such as CN112234364B. Figure 4 It can be seen that the rubber-based aircraft mouthpiece has a good absorption effect on electromagnetic waves of 2GHz-18GHz (especially the absorption effect on electromagnetic waves of 4GHz-16GHz).

[0079] In summary, this rubber-based aircraft cover not only has excellent electromagnetic wave absorption properties, but also good structural strength, wear resistance, and fatigue resistance.

[0080] Example 2 The difference between the rubber-based aircraft door cover prepared in Example 2 and that in Example 1 is that the microwave absorbing agent in the wear-resistant layer microwave absorbing prepreg, the structural layer microwave absorbing prepreg, and the microwave absorbing silicone rubber layer is all Co-Ni-C coated carbonyl iron material, that is, the carbonyl iron powder is replaced with Co-Ni-C coated carbonyl iron material.

[0081] The preparation steps of Co-Ni-C coated carbonyl iron materials include: 1. Weigh 10 g of carbonyl iron powder and place it in 200 mL of anhydrous ethanol, then ultrasonically clean for 30 min; 2. Separate the carbonyl iron powder from step 1 using a magnet and dry it at 70°C for 4 hours; 3. Weigh 2 g of the above-treated carbonyl iron powder and 0.2 g of polyvinylpyrrolidone and add them to 200 mL of methanol. Stir well to form a suspension. 4. Weigh 1.2 g of cobalt nitrate hexahydrate and 1.2 g of nickel nitrate hexahydrate and add them to the suspension prepared in step 3. Stir for 1 h to obtain solution A; 5. Weigh 7.68 g of dimethylimidazole and dissolve it in 200 mL of methanol. Stir well to obtain solution B. 6. Slowly mix solution A and solution B and stir for 1 hour, then let stand for 24 hours to obtain a mixture containing precipitate; 7. Separate the precipitate from the mixture, then wash the precipitate with methanol or anhydrous ethanol, and then dry the precipitate at 70°C for 4 h. 8. Transfer the precipitate obtained in step 7 to a tube furnace. Under an argon atmosphere, heat the dried precipitate to 600°C at a heating rate of 4°C / min. Hold the temperature for 3 hours and then cool it with the furnace to obtain Co-Ni-C coated carbonyl iron material.

[0082] The other process conditions and steps in Example 2 are the same as those in Example 1, and will not be repeated here.

[0083] The electromagnetic absorption performance of the rubber-based aircraft mouthpiece prepared in Example 2 was tested, and the test results are as follows: Figure 5 As shown. Figure 5 As shown, the rubber-based aircraft mouthpiece exhibits excellent absorption performance for electromagnetic waves in the 2GHz-18GHz range (especially for electromagnetic waves in the 4GHz-16GHz range); simultaneously, the reflectivity of the rubber-based aircraft mouthpiece can reach below -25dB, which is superior to the electromagnetic absorption performance of the rubber-based aircraft mouthpiece in Example 1. This indicates that using Co-Ni-C coated carbonyl iron material as an absorber can further improve the electromagnetic absorption performance of the rubber-based aircraft mouthpiece.

[0084] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a rubber-based aircraft mouthpiece, characterized in that, Includes the following steps: S1: Preparation of wear-resistant layer microwave absorbing prepreg and structural layer microwave absorbing prepreg; The wear-resistant layer microwave absorbing prepreg includes a first base film and a first microwave absorbing adhesive film laminated with the first base film; the first microwave absorbing adhesive film comprises a first composition and a first microwave absorbing agent, wherein the mass of the first microwave absorbing agent accounts for 60%-80% of the total mass of the first microwave absorbing adhesive film; by mass parts, the first composition comprises 30-40 parts of first epoxy resin, 10-15 parts of first toughening agent, 1-5 parts of first accelerator, 15-30 parts of first modifier, 5-15 parts of first curing agent and 1-3 parts of wear-resistant agent; The structural layer microwave absorbing prepreg includes a second base film and a second microwave absorbing adhesive film laminated with the second base film; the components of the second microwave absorbing adhesive film include a second composition and a second microwave absorbing agent, wherein the mass of the second microwave absorbing agent accounts for 60%-80% of the total mass of the second microwave absorbing adhesive film; by mass parts, the second composition includes 30-40 parts of a second epoxy resin, 10-15 parts of a second toughening agent, 1-5 parts of a second accelerator, 15-30 parts of a second modifier and 5-15 parts of a second curing agent; S2: At least one layer of the wear-resistant microwave absorbing prepreg and multiple layers of the structural microwave absorbing prepreg are stacked to obtain an intermediate body; and the intermediate body is vacuumed to make it dense; wherein, multiple layers of the structural microwave absorbing prepreg are stacked sequentially, and the wear-resistant microwave absorbing prepreg is located on the outermost side of the intermediate body. S3: The intermediate is placed in an autoclave and heated to cure, thereby obtaining a laminate; wherein the curing temperature is 150℃-185℃, the curing time is 3-7 hours, and the curing pressure is 0.3-0.6MPa; S4: Prepare a microwave absorbing silicone rubber layer, wherein the components of the microwave absorbing silicone rubber layer include a third composition and a third microwave absorbing agent, wherein the mass of the third microwave absorbing agent accounts for 60%-80% of the total mass of the microwave absorbing silicone rubber layer; and the third composition comprises 40-50 parts of silicone rubber and 0.8-1 parts of vulcanizing agent by mass. S5: A rubber treatment agent is coated on the surface of the laminate away from the wear-resistant layer microwave-absorbing prepreg, and then dried to cure the rubber treatment agent; the microwave-absorbing silicone rubber layer is laminated with the side of the laminate coated with the rubber treatment agent, and then the microwave-absorbing silicone rubber layer and the laminate are vulcanized to obtain a rubber-based aircraft door cover; wherein the vulcanization temperature is 150℃~190℃, the vulcanization time is 10 minutes~60 minutes, and the vulcanization pressure is 10MPa~15MPa.

2. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, Both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, and the low-viscosity epoxy resins include one or more of bisphenol F type epoxy resin and dicyclopentadiene phenol epoxy resin; both the first toughening agent and the second toughening agent include one or more of polyetherimide, polystyrene and polyimide; both the first accelerator and the second accelerator include KH-560 silane coupling agent; both the first modifier and the second modifier include one or more of dimethyldichlorosilane and MX-153 modifier; both the first curing agent and the second curing agent include one or more of diethylenetriamine, polyamide, N-aminoethylpiperazine and 4,4'-diaminodiphenyl sulfone; and the wear-resistant agent includes one or more of aramid micro powder and polyethylene micro powder.

3. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The first, second, and third microwave absorbing agents each comprise one or more of iron powder, carbonyl iron powder, carbon powder, and alloy powder.

4. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The first, second, and third microwave absorbers are all Co-Ni-C coated carbonyl iron materials. The preparation method of the Co-Ni-C coated carbonyl iron material includes the following steps: (1) Add carbonyl iron powder and polyvinylpyrrolidone to methanol and stir until homogeneous to obtain a suspension; then add cobalt nitrate hexahydrate and nickel nitrate hexahydrate to the suspension and stir until homogeneous to obtain solution A; And dissolve dimethylimidazole in methanol and stir until homogeneous to obtain solution B; The mass fractions of the carbonyl iron powder, the polyvinylpyrrolidone, the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate, and the dimethylimidazole are as follows: 100 parts of carbonyl iron powder, 5-15 parts of polyvinylpyrrolidone, 20-80 parts of cobalt nitrate hexahydrate, 20-80 parts of nickel nitrate hexahydrate, and 300-600 parts of dimethylimidazole. (2) Mix the solution A and the solution B and stir until homogeneous, then let stand for a period of time to obtain a mixture containing precipitate; (3) Separate the precipitate from the mixture, then wash the precipitate, and then dry the precipitate; (4) Under an inert gas atmosphere, the dried precipitate is heated to 400℃-700℃ at a heating rate of 2-8℃ / min, and then kept at the temperature for 1-5 hours to obtain the Co-Ni-C coated carbonyl iron material.

5. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The first base film is quartz fiber cloth, glass fiber cloth or polyester cloth, and the second base film is quartz fiber cloth, glass fiber cloth or polyester cloth.

6. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The preparation method of the wear-resistant layer microwave absorbing prepreg includes the following steps: The first epoxy resin, the first toughening agent, the first accelerator, the first modifier, the first curing agent and the wear-resistant agent are mixed evenly, and then the first microwave absorbing agent is added and mixed evenly to obtain the first intermediate material; then the first intermediate material is rolled to obtain the first microwave absorbing film. The first microwave absorbing adhesive film is laminated with the first base film, and then rolled to combine the first microwave absorbing adhesive film and the first base film together, thus obtaining the wear-resistant layer microwave absorbing prepreg.

7. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The preparation method of the structural layer microwave absorbing prepreg includes the following steps: The second epoxy resin, the second toughening agent, the second accelerator, the second modifier, and the second curing agent are mixed evenly, and then the second microwave absorbing agent is added and mixed evenly to obtain the second intermediate material; then the second intermediate material is rolled to obtain the second microwave absorbing film. The second microwave absorbing adhesive film is laminated with the second base film, and then rolled to combine the second microwave absorbing adhesive film and the second base film together, thus obtaining the wear-resistant layer microwave absorbing prepreg.

8. The method for preparing the rubber-based aircraft mouthpiece as described in claim 1, characterized in that, The first base film has a porous structure and is provided with a plurality of first mesh holes; in the wear-resistant layer microwave absorbing prepreg, the first microwave absorbing adhesive film is disposed on opposite sides of the first base film, and the first microwave absorbing adhesive films on opposite sides of the first base film are connected through the first mesh holes. And / or, the second base film has a porous structure, and the second base film is provided with a plurality of second mesh holes; In the prepreg of the structural layer, the second absorbing adhesive film is disposed on opposite sides of the second base film, and the second absorbing adhesive films on opposite sides of the second base film are connected through the second mesh.

9. The method for preparing a rubber-based aircraft mouthpiece as described in any one of claims 1-8, characterized in that, The thickness of the first base film is 0.05mm-0.2mm, and the thickness of the first microwave absorbing adhesive film is 0.05mm-0.1mm; the thickness of the second base film is 0.05mm-0.2mm, and the thickness of the second microwave absorbing adhesive film is 0.05mm-0.1mm; the thickness of the intermediate is 1.2mm-6mm; and the thickness of the microwave absorbing silicone rubber layer is 0.3±0.1mm.

10. A rubber-based aircraft mouthpiece, characterized in that, It is manufactured using the method for preparing a rubber-based aircraft mouthpiece as described in any one of claims 1-9.

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