Composite wave absorbing piece and preparation method thereof
By adopting a composite absorber structure in the absorber material, including the absorber skeleton and polyurethane sponge, the problem that existing absorber materials are prone to fall off during use is solved, and efficient and environmentally friendly absorber performance is achieved, and production costs are reduced.
Patent Information
- Application Number
- CN202411614760.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-25
AI Technical Summary
During use, existing absorbent materials are prone to fall off the wave absorbent and flame retardant, causing environmental pollution and reduced absorption performance. At the same time, the preparation process is complex, the production efficiency is low, and the cost is high.
The composite absorber structure is adopted, including two parts: an absorber frame and a polyurethane sponge. The absorber frame is made of polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotubes and nickel-plated calcium silicate. The polyurethane sponge is covered on the outer periphery of the skeleton body, and the polyurethane sponge is limited through the bottom support and tip to avoid falling off.
It improves wave absorption performance, extends service life, reduces process difficulty and production costs, and is environmentally friendly, does not easily age, and is easy to install and handle.
Smart Images
Figure CN119521640A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to absorbing material technology, and in particular to a composite absorbing component and a preparation method thereof. Background Art
[0002] At present, the absorbing materials used in most domestic anechoic chambers are mainly of two types: soft polyurethane foam and non-woven absorbing materials. Among them, soft polyurethane foam material is a traditional absorbing material for anechoic chambers. Its preparation process includes cutting, molding, impregnation and drying. Its advantages are simple process, low cost, low equipment requirements, high production efficiency and strong absorbing ability, but the above polyurethane foam also has many shortcomings. First, during the preparation process, flame retardants and absorbers are adsorbed in the pores of polyurethane foam through impregnation treatment. As the service life increases, they are easy to fall off and cause environmental pollution; second, polyurethane foam is an open pore and easy to absorb moisture, resulting in a decrease in absorbing performance; third, in EMC anechoic chambers, in order to obtain good low-frequency performance, polyurethane foam is often made into long wedges, but after a period of use, due to its own weight, the tip of the material pyramid will bend, that is, droop, which makes the aesthetics of the anechoic chamber worse and the overall anechoic chamber performance decrease.
[0003] The preparation process of non-woven absorbing materials generally includes coating, creasing, folding and assembly processes. The advantages of this absorbing material are strong flame retardancy and better power resistance than polyurethane foam materials. However, its preparation process is relatively complicated and requires more labor, so the production efficiency is low and the cost is relatively high compared to polyurethane foam materials. Secondly, due to the large number of manual processes, product consistency is difficult to ensure, and long-term use can easily cause the absorbent and flame retardant to fall off, polluting the environment and reducing the absorbing performance.
[0004] In addition, there is also an absorbing polyurethane sponge / hard foam composite material, which uses absorbing polyurethane sponge as the matrix, fills the hard foam foaming material into the polyurethane sponge pores, and forms a hard absorbing foam after curing. The absorbing polyurethane sponge is obtained by impregnating a non-absorbing polyurethane sponge sheet with absorbent slurry multiple times and drying it. The hard foam is filled in the polyurethane sponge pores, which can be absorbing foam or non-absorbing foam. In the preparation process of this material, the drying has extremely strict temperature requirements. If the temperature is too high, the polyurethane sponge sheet will easily deform. If the temperature is too low, the resin cannot be partially cured to play a bonding role. It is easy to soak it off after dipping again, resulting in poor yield. In addition, the curing process temperature of the hard foam is 80℃~120℃, and the time is 2h~4h. The curing time of the hard foam is relatively long, resulting in a long production cycle and high cost. The foaming material of the hard foam contains isocyanate, which will threaten human health and life safety, and cannot be recycled, which will damage the environment. Furthermore, the foaming material of rigid foam is brittle, easy to age and fall apart, and difficult to carry. Summary of the invention
[0005] In order to solve one of the above technical defects, a composite absorbing element and a preparation method thereof are provided in an embodiment of the present application.
[0006] According to a first aspect of an embodiment of the present application, a composite absorbing member is provided, comprising:
[0007] The absorbing frame comprises: a base, a frame body and a tip; the frame body is arranged on the upper surface of the base, and the cross-sectional area of the bottom end of the frame body is smaller than the upper surface area of the base; the tip is arranged on the top end of the frame body, and the top end of the tip is a pointed structure; the cross-sectional area of the bottom end of the tip is larger than the cross-sectional area of the top end of the frame body; the base, the frame body and the tip are integrally formed;
[0008] The polyurethane sponge is coated on the outer periphery of the skeleton body and is located between the base and the tip.
[0009] According to a second aspect of an embodiment of the present application, a method for preparing a composite absorbing member is provided, comprising:
[0010] An integrated wave-absorbing skeleton is prepared by using polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotubes and nickel-plated calcium silicate; the wave-absorbing skeleton comprises a base, a skeleton body and a tip; the skeleton body is arranged on the upper surface of the base, and the cross-sectional area of the bottom end of the skeleton body is smaller than the upper surface area of the base; the tip is arranged at the top end of the skeleton body, and the top end of the tip is a pointed structure; the cross-sectional area of the bottom end of the tip is larger than the cross-sectional area of the top end of the skeleton body;
[0011] The wave absorbing frame and polyurethane are placed in a mold for forming, and the polyurethane is coated on the outer periphery of the frame body and is located between the tip and the bottom support to form a polyurethane sponge.
[0012] The technical solution provided by the embodiment of the present application is that the composite wave absorbing part includes a wave absorbing frame and a polyurethane sponge, wherein the wave absorbing frame includes: a bottom support, a frame body and a tip; the frame body is arranged on the upper surface of the bottom support, and the cross-sectional area of the bottom end of the frame body is smaller than the upper surface area of the bottom support; the tip is arranged at the top end of the frame body, and the top end of the tip is a pointed structure; the cross-sectional area of the bottom end of the tip is larger than the cross-sectional area of the top end of the frame body; the bottom support, the frame body and the tip are integrally formed; the polyurethane sponge is coated on the periphery of the frame body and is located between the bottom support and the tip, and the polyurethane sponge is limited by the bottom support and the tip to avoid the polyurethane sponge from being separated from the wave absorbing frame, which can ensure reliability. In addition, the wave absorbing frame and the polyurethane sponge are made into two parts, and the wave absorbing frame can be made of a material with a relatively high hardness, so that the tip is not easy to bend and droop, thereby improving the wave absorbing performance. In addition, the above scheme improves the strict temperature requirements of the process of filling the hard foam in the pores of the polyurethane sponge in the traditional scheme, thereby reducing the process difficulty, shortening the production cycle, and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0014] Figure 1 A schematic diagram of the structure of a composite absorbing member provided in an embodiment of the present application;
[0015] Figure 2 A schematic diagram of the structure of an absorbing skeleton in a composite absorbing member provided in an embodiment of the present application;
[0016] Figure 3 This is a schematic diagram of the structure of the polyurethane sponge in the composite absorber provided in an embodiment of the present application.
[0017] Reference numerals:
[0018] 1-wave absorbing frame; 11-bottom support; 12-frame body; 13-tip portion; 14-plug-in portion;
[0019] 2-polyurethane sponge; 21-inner hole. DETAILED DESCRIPTION
[0020] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0021] This embodiment provides a composite wave absorbing member that can be used in a dark room to absorb electromagnetic waves.
[0022] like Figures 1 to 3 As shown, this embodiment provides a composite absorbing member, including: an absorbing frame 1 and a polyurethane sponge 2. The absorbing frame 1 includes an integrally formed bottom bracket 11, a frame body 12 and a tip portion 13. The frame body 12 is arranged on the upper surface of the bottom bracket 11, and the tip portion 13 is arranged at the top of the frame body 12, and the top of the tip portion 13 is a pointed structure.
[0023] The cross-sectional area of the bottom end of the skeleton body 12 is smaller than the upper surface area of the base 11, and the cross-sectional area of the bottom end of the tip 13 is larger than the cross-sectional area of the top end of the skeleton body 12. The polyurethane sponge 2 is wrapped around the outer periphery of the skeleton body 12 and is located between the base 11 and the tip 13. The base 11 and the tip 13 play a role in limiting the polyurethane sponge 2.
[0024] The polyurethane sponge 2 is formed by foaming a polyurethane material. The base 11, the skeleton body 12 and the tip 13 are integrally formed, and can be made of a material with a hardness greater than that of polyurethane, for example. In the preparation process, the absorbing skeleton 1 is first prepared, and then the absorbing skeleton 1 is placed in a mold, and the polyurethane material is placed so that the polyurethane material is coated on the periphery of the skeleton body 12 in the absorbing skeleton 1 to form a composite absorbing member.
[0025] The technical solution provided in this embodiment is that the composite wave absorbing part includes two parts, namely, a wave absorbing skeleton and a polyurethane sponge, wherein the wave absorbing skeleton includes: a bottom support, a skeleton body and a tip; the skeleton body is arranged on the upper surface of the bottom support, and the cross-sectional area of the bottom end of the skeleton body is smaller than the upper surface area of the bottom support; the tip is arranged at the top end of the skeleton body, and the top end of the tip is a pointed structure; the cross-sectional area of the bottom end of the tip is larger than the cross-sectional area of the top end of the skeleton body; the bottom support, the skeleton body and the tip are integrally formed; the polyurethane sponge is coated on the periphery of the skeleton body and is located between the bottom support and the tip, and the polyurethane sponge is limited by the bottom support and the tip to avoid the polyurethane sponge from being separated from the wave absorbing skeleton, so as to ensure reliability. In addition, the wave absorbing skeleton and the polyurethane sponge are made into two parts, and the wave absorbing skeleton can be made of a material with a relatively high hardness, so that the tip is not easy to bend and droop, thereby improving the wave absorbing performance. In addition, the above scheme improves the strict temperature requirements of the process of filling the hard foam in the pores of the polyurethane sponge in the traditional scheme, thereby reducing the process difficulty, shortening the production cycle, and reducing the production cost.
[0026] On the basis of the above technical solution, this embodiment provides a specific implementation method: in the above-mentioned absorbing skeleton 1, the tip 13 is in the shape of a regular tetrahedron, and the base 11 is also in the shape of a tetrahedron. The side wall of the polyurethane sponge 2 is surrounded by a regular tetrahedron, and the edges of the polyurethane sponge 2 correspond to the edges of the tip 13 and the edges of the base 11, and the side of the polyurethane sponge 2 corresponds to the side of the tip 13 and the side of the base 11, so that the polyurethane sponge 2, the tip 13 and the base 11 are assembled into a regular tetrahedron. The regular tetrahedron structure has excellent broadband performance under vertical incidence and oblique incidence conditions, and also has good scattering and isolation attenuation performance, which is suitable for various parts in a dark room.
[0027] The skeleton body 12 is truncated, and the polyurethane sponge 2 has an inner hole 21 with a circular cross section. The cross-sectional area of the inner hole 21 gradually increases along the center pin direction of the inner hole 21. This solution can reduce the problem of the force between the polyurethane sponge 2 and the absorbing skeleton 1 being concentrated at a certain point, thereby causing damage.
[0028] Furthermore, in the above-mentioned absorbing frame 1, the lower surface of the base 11 is further provided with an inserting portion 14, which protrudes from the lower surface of the base 11, and can be in a rectangular parallelepiped, cylindrical, etc. A plurality of inserting holes are provided on the base, and the absorbing frame 1 is placed on the base through the inserting portion 14, which is convenient for overall storage and transportation, and meets various scenarios such as vertical, horizontal, and inverted installation.
[0029] On the basis of the above technical solution, this embodiment further provides a method for preparing a composite absorbing member, which is used to prepare the above composite absorbing member.
[0030] Firstly, polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotube and nickel-plated calcium silicate are used to prepare an integrated wave-absorbing skeleton.
[0031] The absorbing frame 1 includes a base 11, a frame body 12 and a tip 13, wherein the frame body 12 is arranged on the upper surface of the base 11, and the cross-sectional area of the bottom end of the frame body 12 is smaller than the upper surface area of the base 11; the tip 13 is arranged at the top end of the frame body 12, and the top end of the tip 13 is a pointed structure; the cross-sectional area of the bottom end of the tip 13 is larger than the cross-sectional area of the top end of the frame body 12. The specific implementation of the absorbing frame 1 can refer to the above content.
[0032] Then, the absorbing frame 1 and the polyurethane are placed in a mold for molding. The polyurethane is coated on the outer periphery of the frame body 12 and is located between the tip portion 13 and the base 11 to form the polyurethane sponge 2 .
[0033] In the above scheme, the base, the main frame and the tip are integrally formed; the polyurethane sponge is coated on the periphery of the main frame and is located between the base and the tip. The polyurethane sponge is limited by the base and the tip to avoid separation of the polyurethane sponge from the absorbing frame, which can ensure reliability. The absorbing frame and the polyurethane sponge are made into two parts, and the absorbing frame can be made of a material with a relatively high hardness, so that the tip is not prone to bending and sagging, thereby improving the absorbing performance. In addition, the above scheme improves the strict temperature requirements of the process of filling the hard foam in the pores of the polyurethane sponge in the traditional scheme, thereby reducing the process difficulty, shortening the production cycle, and reducing the production cost.
[0034] Furthermore, the above-mentioned use of polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotubes, and nickel-plated calcium silicate to prepare an integrated wave absorbing skeleton can be specifically carried out in the following manner:
[0035] Step 1: Mix 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate in a weight ratio.
[0036] Step 2: Melt and plasticize the mixed materials into granules through a twin-screw extruder.
[0037] Step 3: foaming the granular material to obtain foamed particles.
[0038] Step 4: pre-press the foamed particles into a shape, and then dry them to obtain a wave-absorbing skeleton.
[0039] After the absorbing frame is obtained, the absorbing frame is placed in a mold and filled with polyurethane foam to form a composite absorbing member.
[0040] The above scheme uses the absorbing material as the matrix, fills the absorbing material with polyurethane, and forms a composite absorbing component with good toughness, environmental protection and wider working frequency band after curing.
[0041] The above step 1 can be implemented as follows:
[0042] First, the granular superconducting carbon nanotubes are put into a grinder and ground into powder particles with a preset diameter, which may be about 30 nanometers.
[0043] Then, nickel sulfate, sodium hypophosphite and sodium citrate dihydrate are dissolved in distilled water, and the activated calcium silicate is put into the solution to prepare nickel-plated calcium silicate.
[0044] Then, the temperature of the mixer is preheated to about 120° C., and 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate are placed in the mixer and stirred at high speed for about 30 minutes to make the mixture uniform. Conductive masterbatch can also be added during the process.
[0045] The above step 2 is specifically as follows: putting the mixed material in step 1 into a twin-screw extruder, so that the mixed material is fully dispersed and plasticized at a preset temperature, and the preset temperature may be about 190°C.
[0046] The mixed material is extruded through a die head by drawing, with a diameter of about 1mm. Then it is cut into particles of uniform length by a high-precision tool, with a particle length of about 1mm. Then the particles with too small length are filtered out by a vibrating screen to obtain high polymer polypropylene PP particles.
[0047] The above step 3 is specifically as follows: the granular material (i.e., PP particles) obtained in step 2 is placed in a reactor, the temperature in the reactor is controlled at about 140°C, carbon dioxide is introduced into the reactor, and foaming is performed under a preset pressure, and the pressure is instantly released into the atmosphere to obtain foamed particles. The preset pressure can be 4.5MPa, and the foaming ratio is 15 times.
[0048] The above step 4 is specifically as follows: the material foamed in the reactor in step 3 is placed in a pre-pressing tank for pre-pressing, and is molded into an absorbing skeleton 1 by high-pressure steam, the pressure is 4MPa, and the molding time is only 1min-3min. Then the absorbing skeleton 1 is pre-pressed for 12 hours. The pre-pressed absorbing material is placed in a drying room for drying at a drying temperature of about 80°C for 2 hours to obtain a dry absorbing skeleton 1.
[0049] Nickel-plated calcium silicate can withstand high temperatures of 1540°C, can enhance the toughness of foamed products, improve tensile strength, and prevent products from aging easily; nickel-plated calcium silicate itself is conductive, and when combined with conductive masterbatches and superconducting carbon nanotubes, it can form a material with better conductive properties, which plays a positive role in improving the material's wave absorption and broadening the working frequency band of the wave-absorbing material.
[0050] In addition, carbon dioxide foaming is adopted without adding any foaming agent, thus avoiding the use of toxic foaming agents. Generally, foaming agents will weaken the flame retardant effect, so this embodiment is more environmentally friendly.
[0051] Pre-prepare the absorbent slurry, specifically: weigh a certain mass of conductive carbon black, carbon nanotube powder, and modified epoxy resin and pour them into plasma water and stir them thoroughly to obtain the absorbent slurry. The mass ratio of the total mass of the conductive carbon black, carbon nanotube powder, and modified epoxy resin to the plasma water is 5:1, for example: the total mass of the conductive carbon black, carbon nanotube powder, and modified epoxy resin is 1kg, and the plasma water level is 5kg.
[0052] The shaped absorbing skeleton obtained in step 4 is placed in a wedge-shaped absorbing structure mold and coated with a mold release agent, and then polyurethane is poured into the absorbing structure mold for foaming, the foaming temperature is about 25°C, and the foaming and curing time is only 5min-6min, to obtain an absorbing foamed polypropylene (EPP) / polyurethane composite absorbing material, that is, the above-mentioned composite absorbing component. This process is also relatively short.
[0053] Afterwards, the formed composite absorbing part (i.e., absorbing EPP / polyurethane composite material) is immersed in the absorbent slurry, and then dried at 100℃-120℃ for 3 times to solidify the absorbent slurry, and finally a composite absorbing part is obtained. The performance of the working frequency band of the absorbing material is improved, and due to the presence of the EPP absorbing material, the overall material has better toughness, is not easy to age, and is easy to install or carry.
[0054] The above preparation method has a short molding time and a short curing time, which greatly shortens the production cycle and labor costs.
[0055] In the above preparation method, 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate are mixed by weight; the mixed materials are melted and plasticized into granules by a double-screw extruder; the granular materials are foamed to obtain foamed particles; the foamed particles are pre-pressed and then dried to obtain an absorbing skeleton; the absorbing skeleton and polyurethane are placed in a mold for molding, and then the molded part is placed in an absorbent slurry for immersion and drying to obtain a composite absorbing part. Such a composite absorbing part has a wider working frequency band, better toughness, is not easy to age during long-term work, and is easy to carry; it is non-toxic, harmless, flame-retardant, does not add any heavy metals, and has better environmental protection performance; in addition, the preparation method provided in this embodiment has a shorter cycle, reduces the material molding conditions, and reduces the manufacturing cost while improving production efficiency.
[0056] Furthermore, the absorbing skeleton made of the above-mentioned material has a high strength at the tip 13 and is not prone to problems such as sagging, which can improve the effect of absorbing electromagnetic waves in a dark room and extend the service life.
[0057] The polyurethane sponge 2 is wrapped on the absorbing frame 1, and the absorbing frame 1 can work stably at -40°C to 130°C. In addition, the absorbing frame 1 is light in weight and has good strength, which can avoid high-temperature deformation or falling off during polyurethane impregnation.
[0058] The molding time of the composite absorbing part is within 1-3 minutes, the curing time is short, the production cycle is greatly shortened, and the production cost is greatly reduced.
[0059] No additives are used in the EPP foaming process. Carbon dioxide is used for foaming. The entire production process is more environmentally friendly and does not cause pollution to the environment.
[0060] Due to the presence of the EPP absorbing skeleton, EPP has good toughness, light weight, and aging resistance, avoiding the brittle material problem of other hard foam materials, avoiding aging and falling off during transportation, and greatly improving the convenience of installation.
[0061] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0062] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0063] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0064] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0065] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A composite absorbing member, characterized in that: include: Wave absorbing skeleton; The wave absorbing frame comprises: a base, a frame body and a tip portion; the frame body is arranged on the upper surface of the base, and the cross-sectional area of the bottom end of the frame body is smaller than the upper surface area of the base; the tip portion is arranged at the top end of the frame body, and the top end of the tip portion is a pointed structure; the cross-sectional area of the bottom end of the tip portion is larger than the cross-sectional area of the top end of the frame body; the base, the frame body and the tip portion are integrally formed; The polyurethane sponge is coated on the outer periphery of the skeleton body and is located between the base and the tip.
2. The composite absorber according to claim 1, characterized in that: The tip is a regular quadrangular pyramid.
3. The composite absorber according to claim 1, characterized in that: The main body of the skeleton is in the shape of a truncated cone.
4. The composite absorbing member according to claim 2, characterized in that: The side wall of the polyurethane sponge is in the shape of a regular quadrangular pyramid, and the edges of the polyurethane sponge correspond to the edges of the tip, and the side surfaces of the polyurethane sponge correspond to the side surfaces of the tip.
5. The composite absorber according to claim 4, characterized in that: The base is in the shape of a regular quadrangular pyramid; the edges of the base correspond to the edges of the polyurethane sponge, and the side surfaces of the base correspond to the side surfaces of the polyurethane sponge.
6. A method for preparing a composite absorbing member, characterized in that: include: An integrated wave-absorbing skeleton is prepared by using polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotubes and nickel-plated calcium silicate; the wave-absorbing skeleton comprises a base, a skeleton body and a tip; the skeleton body is arranged on the upper surface of the base, and the cross-sectional area of the bottom end of the skeleton body is smaller than the upper surface area of the base; the tip is arranged at the top end of the skeleton body, and the top end of the tip is a pointed structure; the cross-sectional area of the bottom end of the tip is larger than the cross-sectional area of the top end of the skeleton body; The wave absorbing frame and polyurethane are placed in a mold for forming, and the polyurethane is coated on the outer periphery of the frame body and is located between the tip and the bottom support to form a polyurethane sponge.
7. The preparation method according to claim 6, characterized in that: The integrated wave absorbing skeleton is prepared by using polypropylene, flame retardant, antioxidant, powdered superconducting carbon nanotubes and nickel-plated calcium silicate, including: Mixing 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate in a weight ratio; The mixed materials are melted and plasticized into granules through a twin-screw extruder; foaming the granular material to obtain foamed particles; The foamed particles are pre-pressed and then dried to obtain a wave-absorbing skeleton.
8. The preparation method according to claim 7, characterized in that: Mixing 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate in a weight ratio, including: Putting granular superconducting carbon nanotubes into a grinder and grinding them into powder particles with a preset diameter; Dissolve nickel sulfate, sodium hypophosphite and sodium citrate dihydrate in distilled water, and add activated calcium silicate into the solution to prepare nickel-plated calcium silicate; Preheat the temperature of the mixer, then put 50%-80% of polypropylene, 20%-30% of flame retardant, 5%-10% of antioxidant, 1%-5% of powdered superconducting carbon nanotubes, and 1%-10% of nickel-plated calcium silicate into the mixer and stir to make the mixture uniform.
9. The preparation method according to claim 7, characterized in that: The tip is a regular quadrangular pyramid, and the base is a regular quadrangular pyramid; the side walls of the polyurethane sponge are shaped like a regular quadrangular pyramid; the edges of the polyurethane sponge correspond to the edges of the tip and the edges of the base, and the sides of the polyurethane sponge correspond to the sides of the tip and the sides of the base.
10. The preparation method according to claim 9, characterized in that: The skeleton body is in the shape of a truncated cone.