Rapid prototyping impact-resistant honeycomb wave-absorbing composite material and preparation method thereof

Abstract

The application discloses a kind of quick forming impact honeycomb wave-absorbing composite material and preparation method thereof, it is related to electromagnetic wave-absorbing material and thermoplastic composite material manufacturing field.The weight parts of raw materials include as follows: modified additive 11-14 parts, isocyanate 12-18 parts, PPTA solution 40-60 parts, PA plastic film 100-150 parts, glass fiber 48-80 parts, ultra-high molecular weight polyethylene fiber 80-112 parts, wherein, modified additive is one or more of carbon black, carbon nanotube, carbonyl iron powder;The molecular weight of ultra-high molecular weight polyethylene fiber is 1 million-5 million.The application uses modified additive to dope and blend in PPTA solution, can obtain the aramid paper with higher wave-absorbing performance, and then make wave-absorbing aramid honeycomb core, improve the application of absorbent in wave-absorbing, meet the demand of high-performance product, simultaneously, in the last honeycomb board production link, use new isocyanate fast curing adhesive, shorten the forming time of honeycomb board from 8 hours to 1 minute, greatly improve production efficiency, save energy consumption.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorbing materials and thermoplastic composite material manufacturing, specifically to a rapid prototyping impact-resistant honeycomb wave absorbing composite material and its preparation method. Background Technology

[0002] With the continuous advancement of modern electromagnetic and electronic information technologies, radar has become one of the primary means of target detection. Radar achieves its detection function through the reflection of electromagnetic waves, and electromagnetic stealth technology can reduce the reflection of electromagnetic waves, significantly reducing the radar cross section (RCS) of weapons and equipment, shortening the distance at which they can be detected by radar, and achieving stealth from radar. In modern high-tech information warfare, in order to improve survivability, all advanced weapons must possess electromagnetic stealth capabilities.

[0003] Electromagnetic absorbing materials are a class of materials that can dissipate the energy of electromagnetic waves through electromagnetic conversion, thereby reducing the amount of electromagnetic waves that pass through the material and achieving the purpose of stealth. When an incident electromagnetic wave acts on the material, there are three possible outcomes: some electromagnetic waves are reflected at the surface of the material, forming reflected electromagnetic waves; another part of the electromagnetic waves are absorbed inside the material, forming absorbed electromagnetic waves; and finally, the remaining unabsorbed electromagnetic waves pass through the material, forming transmitted electromagnetic waves.

[0004] Resin-based fiber-reinforced composites are the most commonly used and widely applied electromagnetic absorbing materials. They have attracted widespread attention due to their advantages such as good chemical stability, lightweight, good toughness, and ease of processing and fabrication. They have numerous applications in aviation, aerospace, shipbuilding, and automotive fields, such as aircraft radomes, antenna radomes, and fuselage skins. Fiber-reinforced resin matrix composites (CFRP) are composite materials that use resin as the matrix and carbon fiber as the reinforcement.

[0005] However, existing fiber-reinforced resin matrix composites still suffer from poor wave absorption performance, and the current molding time for honeycomb panels is as high as 8 hours, making rapid production impossible, resulting in low production efficiency and increasing production costs for enterprises. Summary of the Invention

[0006] This invention provides a rapid-prototyping, impact-resistant honeycomb microwave-absorbing composite material and its preparation method, aiming to solve the problems existing in the background technology. By selecting aramid paper / PA matrix composite material as the research object, and using carbon black dielectric loss powder or carbon nanotube magnetic loss powder to dope and blend in PPTA solution, aramid paper with high microwave absorption performance can be obtained, which is then used to make a microwave-absorbing aramid honeycomb core. This improves the application of absorbent in microwave absorption and meets the needs of high-performance products. At the same time, in the final honeycomb panel production stage, a novel isocyanate rapid-curing adhesive is used, shortening the molding time of the honeycomb panel from 8 hours to 1 minute, greatly improving production efficiency and saving energy.

[0007] To achieve the above-mentioned technical objectives, the present invention mainly adopts the following technical solutions:

[0008] In a first aspect, the present invention discloses a rapid-molding impact-resistant honeycomb absorbing composite material, comprising the following raw materials in parts by weight: 11-14 parts of modifying additives, 12-18 parts of isocyanate, 40-60 parts of PPTA solution, 100-150 parts of PA plastic film, 48-80 parts of glass fiber, and 80-112 parts of ultra-high molecular weight polyethylene fiber, wherein the modifying additives are one or more of carbon black, carbon nanotubes, and carbonyl iron powder; and the ultra-high molecular weight polyethylene fiber has a molecular weight of 1 million to 5 million.

[0009] In a preferred embodiment of the present invention, the modifying additive is one or both of carbon black and carbon nanotubes, and when the modifying additive is carbon black and carbon nanotubes, the weight ratio of carbon black to carbon nanotubes is carbon black: carbon nanotubes = 11-16.5: 0.5-1.

[0010] In a second aspect, the present invention discloses a method for preparing a rapid prototyping impact-resistant honeycomb absorbing composite material as described in the first aspect, comprising the following steps:

[0011] (1) Preparation of microwave-absorbing aramid honeycomb core: Add the modified additive to the PPTA solution, stir evenly, and prepare the microwave-absorbing aramid honeycomb core by the traditional method;

[0012] (2) Preparation of blended fiber cloth: Glass fiber and ultra-high molecular weight polyethylene fiber are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth;

[0013] (3) Preparation of upper and lower transparent skin: PA plastic film and blended fiber cloth are placed into the preheated product mold, the product mold is moved into the hot press, and after hot pressing and molding, the upper and lower transparent skins are obtained.

[0014] (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is moved into the preheated product mold, placed in the hot press for rapid molding, demolded, and the impact-resistant honeycomb absorbing composite material is prepared.

[0015] In a preferred embodiment of the present invention, in step (3), the product mold temperature is 60°C, the PA plastic film and the blended fiber cloth are alternately placed in the product mold, and then hot-pressed using a hot press.

[0016] In a preferred embodiment of the present invention, in step (3), the temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa.

[0017] In a preferred embodiment of the present invention, in step (4), the temperature of the product mold is 60°C; and the temperature of the hot press is 245°C.

[0018] In a preferred embodiment of the present invention, in step (4), the rapid molding time of the hot press is 1 minute.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention provides a rapid prototyping impact-resistant honeycomb absorbing composite material, which uses a method of melt blending and drawing glass fiber and ultra-high molecular weight polyethylene fiber to prepare composite fiber filaments. The composite fiber has both the high strength and high stiffness of glass fiber and the high toughness of polyethylene fiber, so that the composite fiber has good mechanical properties, durability and impact resistance, which can improve the toughness and impact resistance of the composite material and greatly expand the application range of the material.

[0021] (2) The present invention provides a rapid prototyping impact-resistant honeycomb absorbing composite material, which realizes the extended application of absorbing agents such as carbon black and carbon nanotubes in composite materials.

[0022] (3) The present invention introduces microwave absorbing material in the preparation process and mixes the microwave absorbing material into the PPTA solution, thereby improving the designability of microwave absorbing honeycomb.

[0023] (4) The present invention uses a rapid hot pressing molding method to prepare a wave-transparent and impact-resistant skin from PA plastic film and blended fiber cloth. Compared with traditional glass fiber skin, the wave transmittance is greatly improved and the impact resistance is greatly improved, enabling the composite material to be used in more severe working conditions.

[0024] (5) The method for preparing the microwave absorbing honeycomb composite material prepared by the present invention is simple and the molding process is fast, which can greatly reduce the production time and is suitable for industrial production applications, thereby improving market competitiveness. Attached Figure Description

[0025] Figure 1 This is a comparison of the radar absorption reflectivity performance curves of the impact-resistant honeycomb composite materials prepared in Examples 1-4 and Comparative Example 1 of the present invention.

[0026] Figure 2 This is a comparison chart showing the impact resistance performance of the impact-resistant honeycomb composite materials prepared in Examples 1-4 and Comparative Example 1 of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] A method for preparing a rapid prototyping impact-resistant honeycomb microwave absorbing composite material includes the following steps:

[0030] (1) Preparation of microwave-absorbing aramid honeycomb core: Add 9 parts of carbon black to 50 parts of PPTA solution, stir evenly, and prepare microwave-absorbing aramid honeycomb core by traditional methods. Specifically, microwave-absorbing aramid paper can be prepared by cold pressing and hot pressing, and then microwave-absorbing aramid honeycomb core can be prepared by stretching machine and slicing machine.

[0031] (2) Preparation of blended fiber cloth: 112 parts of glass fiber and 48 parts of ultra-high molecular weight polyethylene fiber (molecular weight between 1 million and 5 million) are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth.

[0032] (3) Preparation of upper and lower transparent skin: 120 parts of PA plastic film and the blended fiber cloth prepared in step (2) are alternately placed into the product mold that has been preheated to 60°C. Generally, they are placed alternately in the manner of "PA plastic film-blended fiber cloth-PA plastic film". The product mold is moved into the hot press. The temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. After hot pressing and molding, the mold is demolded to obtain the upper and lower transparent skin.

[0033] (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying 15 parts of isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is preheated to 60°C, and then placed in a hot press for 1 minute to quickly mold and demold to obtain the impact-resistant honeycomb absorbing composite material.

[0034] Example 2

[0035] A method for preparing a rapid prototyping impact-resistant honeycomb microwave absorbing composite material includes the following steps:

[0036] (1) Preparation of microwave-absorbing aramid honeycomb core: 11 parts of carbon black and 0.5 parts of carbon nanotubes are added to 50 parts of PPTA solution and stirred evenly. The microwave-absorbing aramid honeycomb core is prepared by traditional methods, specifically by preparing microwave-absorbing aramid paper by cold pressing and hot pressing, and then preparing microwave-absorbing aramid honeycomb core by stretching machine and slicing machine.

[0037] (2) Preparation of blended fiber cloth: 80 parts of glass fiber and 80 parts of ultra-high molecular weight polyethylene fiber (molecular weight between 1 million and 5 million) are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth.

[0038] (3) Preparation of upper and lower transparent skin: 120 parts of PA plastic film and the blended fiber cloth prepared in step (2) are alternately placed into the product mold that has been preheated to 60°C. Generally, they are placed alternately in the manner of "PA plastic film-blended fiber cloth-PA plastic film". The product mold is moved into the hot press. The temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. After hot pressing and molding, the mold is demolded to obtain the upper and lower transparent skin.

[0039] (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying 15 parts of isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is preheated to 60°C, and then placed in a hot press for 1 minute to quickly mold and demold to obtain the impact-resistant honeycomb absorbing composite material.

[0040] Example 3

[0041] A method for preparing a rapid prototyping impact-resistant honeycomb microwave absorbing composite material includes the following steps:

[0042] (1) Preparation of microwave-absorbing aramid honeycomb core: 12.5 parts of carbon black and 1 part of carbon nanotubes are added to 50 parts of PPTA solution and stirred evenly. The microwave-absorbing aramid honeycomb core is prepared by traditional methods, specifically by preparing microwave-absorbing aramid paper by cold pressing and hot pressing, and then preparing microwave-absorbing aramid honeycomb core by stretching machine and slicing machine.

[0043] (2) Preparation of blended fiber cloth: 48 parts of glass fiber and 112 parts of ultra-high molecular weight polyethylene fiber (molecular weight between 1 million and 5 million) are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth.

[0044] (3) Preparation of upper and lower transparent skin: 120 parts of PA plastic film and the blended fiber cloth prepared in step (2) are alternately placed into the product mold that has been preheated to 60°C. Generally, they are placed alternately in the manner of "PA plastic film-blended fiber cloth-PA plastic film". The product mold is moved into the hot press. The temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. After hot pressing and molding, the mold is demolded to obtain the upper and lower transparent skin.

[0045] (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying 15 parts of isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is preheated to 60°C, and then placed in a hot press for 1 minute to quickly mold and demold to obtain the impact-resistant honeycomb absorbing composite material.

[0046] Example 4

[0047] A method for preparing a rapid prototyping impact-resistant honeycomb microwave absorbing composite material includes the following steps:

[0048] (1) Preparation of microwave-absorbing aramid honeycomb core: 16.5 parts of carbon black and 0.5 parts of carbon nanotubes are added to 50 parts of PPTA solution and stirred evenly. The microwave-absorbing aramid honeycomb core is prepared by traditional methods, specifically by preparing microwave-absorbing aramid paper by cold pressing and hot pressing, and then preparing microwave-absorbing aramid honeycomb core by stretching machine and slicing machine.

[0049] (2) Preparation of blended fiber cloth: 48 parts of glass fiber and 112 parts of ultra-high molecular weight polyethylene fiber (molecular weight between 1 million and 5 million) are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth.

[0050] (3) Preparation of upper and lower transparent skin: 120 parts of PA plastic film and the blended fiber cloth prepared in step (2) are alternately placed into the product mold that has been preheated to 60°C. Generally, they are placed alternately in the manner of "PA plastic film-blended fiber cloth-PA plastic film". The product mold is moved into the hot press. The temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. After hot pressing and molding, the mold is demolded to obtain the upper and lower transparent skin.

[0051] (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying 15 parts of isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is preheated to 60°C, and then placed in a hot press for 1 minute to quickly mold and demold to obtain the impact-resistant honeycomb absorbing composite material.

[0052] Comparative Example 1

[0053] A method for preparing a honeycomb microwave absorbing composite material includes the following steps:

[0054] (1) Weigh out 30 portions of commercially available aramid honeycomb cores;

[0055] (2) Preparation of glass fiber skin: 20 parts epoxy film and 100 parts glass fiber are alternately placed into the product mold that has been preheated to 60°C. Generally, they are placed alternately in the manner of "epoxy film-glass fiber-epoxy film". The product mold is then moved into a hot press. The temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. After hot pressing, the product is demolded to obtain glass fiber skin.

[0056] (3) Preparation of honeycomb absorbing composite material: The glass fiber skin and aramid honeycomb core are transferred into the product mold preheated to 60°C, placed in the hot press for 8 hours, and demolded to obtain the impact-resistant honeycomb absorbing composite material.

[0057] Test case

[0058] The electromagnetic absorbing composite materials prepared in Examples 1, 2, 3, 4, and Comparative Example 1 were subjected to radar reflectivity testing using the bow-shaped method. The sample size was 300mm × 300mm × 20mm, and the measurement range was C, X, and Ku bands (4GHz-18GHz). The reflectivity test results of the absorbing materials were obtained by frequency sweep measurement, and the unit of reflectivity of the absorbing materials is decibel (dB). The results are shown in Table 1 and... Figure 1 As shown.

[0059] Table 1 Comparison of Reflectivity Test Results of Absorbing Honeycomb Composite Materials

[0060] name C-band reflectivity (dB) X-band reflectivity (dB) Ku-band reflectivity (dB) Example 1 -8 -10 -12 Example 2 -10 -15 -13 Example 3 -12 -17 -15 Example 4 -8 -15 -14 Comparative Example 1 0 0 0

[0061] From Table 1 and Figure 1 The reflectance test curves of the five sets of samples show that the honeycomb absorbing composite materials prepared in Examples 1-4 have lower reflectance and better reflection effect than Comparative Example 1.

[0062] The impact resistance of the electromagnetic wave absorbing composite materials prepared in Examples 1, 2, 3, 4 and Comparative Example 1 was tested and evaluated. The results are shown in Table 2 below. Figure 2 As shown.

[0063] Table 2 Statistical table of drop weight test results for microwave absorbing honeycomb composite materials

[0064] name Example 1 Example 2 Example 3 Example 4 Comparative Example 1 500mm drop hammer test results Not approved pass pass Not approved Not approved

[0065] From Table 2 and Figure 2It can be seen that the drop hammer test results of Examples 1, 4 and Comparative Example 1 of the present invention all failed, indicating that even if modified additives, ultra-high molecular weight polyethylene fiber, PPTA and other raw material components are added to the raw materials, the results will still fail if the ratio is not appropriate, which shows the importance of the ratio of each component in the raw materials.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a rapid-prototyping impact-resistant honeycomb absorbing composite material, characterized in that, A rapid-prototyping impact-resistant honeycomb microwave-absorbing composite material comprises the following raw materials in parts by weight: 11-14 parts of modifying additives, 12-18 parts of isocyanate, 40-60 parts of PPTA solution, 100-150 parts of PA plastic film, 48-80 parts of glass fiber, and 80-112 parts of ultra-high molecular weight polyethylene fiber. The modifying additives are one or more of carbon black, carbon nanotubes, and carbonyl iron powder; the ultra-high molecular weight polyethylene fiber has a molecular weight of 1 million to 5 million. The preparation method includes the following steps: (1) Preparation of microwave-absorbing aramid honeycomb core: Add the modified additive to the PPTA solution, stir evenly, and prepare the microwave-absorbing aramid honeycomb core by the traditional method; (2) Preparation of blended fiber cloth: Glass fiber and ultra-high molecular weight polyethylene fiber are mixed and drawn into blended fiber filaments by hot melt extrusion blending method, and then woven into blended fiber cloth; (3) Preparation of upper and lower transparent skin: PA plastic film and blended fiber cloth are placed into the preheated product mold, the product mold is moved into the hot press, and after hot pressing and molding, the upper and lower transparent skins are obtained. (4) Preparation of impact-resistant honeycomb absorbing composite material: After spraying isocyanate on the inner surface of the upper and lower transparent skin and the surface of the absorbing aramid honeycomb core, the product mold is moved into the preheated product mold, placed in the hot press for rapid molding, demolding, and the impact-resistant honeycomb absorbing composite material is prepared. In step (3), the product mold temperature is 60°C, the PA plastic film and the blended fiber cloth are alternately placed in the product mold, and then hot-pressed using a hot press; the temperature of the hot press is 245°C, the hot pressing time is 30 min, and the hot pressing pressure is 10 MPa. In step (4), the rapid molding time of the hot press is 1 minute; the product mold temperature is 60°C; and the temperature of the hot press is 245°C.

2. The preparation method according to claim 1, characterized in that: The modifying additive is one or both of carbon black and carbon nanotubes, and when the modifying additive is carbon black and carbon nanotubes, the weight ratio of carbon black to carbon nanotubes is carbon black: carbon nanotubes = 11-12.5: 0.5-1.

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