A high-temperature resistant honeycomb core material paper, its preparation method and application

Abstract

This invention discloses a high-temperature resistant honeycomb core paper, its preparation method, and its application. The paper has a three-layer composite structure, including two outer layers and an intermediate layer. The two outer layers are identical in composition, consisting of high-temperature resistant chopped fibers and high-temperature resistant resin. The intermediate layer, located between the two outer layers, comprises high-temperature resistant micro / nano fibers, high-temperature resistant pulp fibers, high-temperature resistant chopped fibers, and high-temperature resistant resin. The high-temperature resistant micro / nano fibers are fibrillated PBO fibers. The high-temperature resistant pulp fibers are PBO pulp fibers. The mass ratio of the high-temperature resistant micro / nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers is 3–15:15–35:50–75. Through material structure design, this invention effectively improves the paper's high-temperature resistance (>250℃) and UV aging resistance.

Description

Technical Field

[0001] This invention belongs to the field of honeycomb composite material technology, and particularly relates to a honeycomb core material paper, its preparation method and application. Background Technology

[0002] Honeycomb sandwich structures, as a typical example of lightweight load-bearing and functional integrated composite materials, are one of the core structural materials supporting the development of modern aerospace equipment towards high mobility, long endurance, and reusability. Compared with traditional metal honeycomb core materials, high-performance fiber-paper-based honeycomb core materials have high specific strength, high specific modulus, excellent flame retardancy, and vibration and noise reduction properties, and have become the mainstream material system to replace metal honeycomb.

[0003] However, with the development of advanced equipment such as hypersonic vehicles and reusable spacecraft, higher requirements are placed on the high-temperature resistance of honeycomb core materials, requiring long-term stable operation in environments above 250℃. Currently, the upper limit of the temperature resistance of widely used aramid fiber paper-based honeycomb is generally no more than 200℃. In existing technologies, honeycomb core paper made with PBO fiber or carbon fiber, although partially improving temperature resistance, often relies on binders with limited temperature resistance, such as poly(m-phenylene isophthalamide), and PBO fiber itself has poor UV resistance, limiting its application in extreme environments. For example, Chinese patent application CN104831579A discloses a microwave-absorbing high-temperature resistant composite paper and its preparation method, but its binder is still aramid pulp with insufficient temperature resistance, which cannot meet the needs of next-generation aerospace equipment.

[0004] Therefore, developing a high-performance honeycomb core material paper that combines excellent high-temperature resistance (>250℃), good UV aging resistance, and suitable wet strength to achieve continuous production has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To overcome the problems in the prior art, the present invention provides a high-temperature resistant honeycomb core material paper, its preparation method and application. This honeycomb core material paper can not only be used for a long time in high-temperature environments above 250°C, but also has excellent UV aging resistance and sufficient wet strength, making it suitable for continuous industrial production and meeting the needs of hypersonic vehicles, spacecraft and other applications for high-performance honeycomb core materials.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] This invention provides a high-temperature resistant honeycomb core material paper, which has a three-layer composite structure, including two outer layers and one middle layer; The two outer layers have the same composition, both consisting of high-temperature resistant short-cut fibers and high-temperature resistant resin; The intermediate layer is located between the two outer layers, and its components include high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, high-temperature resistant chopped fibers, and high-temperature resistant resin. The high-temperature resistant micro / nano fiber is fibrillated PBO fiber; the high-temperature resistant pulp fiber is PBO pulp fiber.

[0008] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers are all fibers with a temperature resistance of >250℃.

[0009] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the mass ratio of high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers and high-temperature resistant chopped fibers in the intermediate layer is 3-15:15-35:50-75.

[0010] In this invention, controlling the quality of high-temperature resistant micro / nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers within the aforementioned range is beneficial for the preparation of the honeycomb core and the improvement of paper performance. Excessive chopped fiber content results in poor paper uniformity and, due to a lack of adhesive—pulp fibers—leads to excessively low strength. Furthermore, excessively high chopped fiber content results in an abnormally loose and porous overall material structure, which can lead to adhesive seepage and penetration during subsequent honeycomb preparation, affecting the preparation of the honeycomb core.

[0011] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the high-temperature resistant micro-nano fibers have a diameter of 50-500 nm and a length of 100-1000 μm.

[0012] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the length of the high-temperature resistant pulp fiber is 0.3 to 1.2 mm.

[0013] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the high-temperature resistant chopped fibers are selected from at least one of carbon fiber, glass fiber or ceramic fiber, and have a length of 3 to 9 mm.

[0014] As an optional embodiment, in the honeycomb core material paper provided by the present invention, the high-temperature resistant resin is selected from one or two of bismaleimide resin or cyanate ester resin (triazine A resin), and the above resin has a temperature resistance >250°C.

[0015] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned high-temperature resistant honeycomb core material paper, comprising the following steps: S1. Prepare a web surface sizing agent by mixing high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers in a specific ratio; prepare a carpet surface sizing agent by mixing high-temperature resistant chopped fibers. S2. The wire surface slurry and the carpet surface slurry prepared in S1 are evenly fed onto the wire through a double-layer headbox and dewatered at the wire section to form a wet paper web; S3. The base paper is obtained by coating the surface of the wet paper web obtained in S2 with a high-temperature resistant resin, and then pressing, drying and curling. S4. The wire mesh of the base paper obtained in S3 is coated with high-temperature resistant resin, and then the wire meshes of the two base papers are laminated and pressed at high temperature to obtain high-temperature resistant honeycomb core material paper.

[0016] As an optional embodiment, in the preparation method provided by the present invention, in S2, the upper layer of the double-layer headbox is used to distribute the carpet surface slurry, and the lower layer is used to distribute the mesh surface slurry. The forming concentration of the carpet surface slurry or the mesh surface slurry is 0.05 to 0.2‰, and the ratio of the slurry flow rate to the forming mesh running speed is 0.9 to 1.

[0017] As an optional embodiment, in the preparation method provided by the present invention, in S3, the solid content of the high-temperature resistant resin is 10-50%, and the amount of sizing is 5-15% of the weight of the base paper.

[0018] As an optional embodiment, in the preparation method provided by the present invention, in S3, the pressing process adopts a three-pressure gradient pressing method, with the first pressure being 5-10 kN / m, the second pressure being 10-25 kN / m, and the third pressure being 35-50 kN / m.

[0019] As an optional embodiment, in the preparation method provided by the present invention, in S4, the solid content of the high-temperature resistant resin is 50-75%, and the amount of sizing is 5-15% of the weight of the base paper.

[0020] Based on the same technical concept, the present invention also provides the application of the above-mentioned high-temperature resistant honeycomb core material paper in aerospace equipment, wherein the high-temperature resistant honeycomb core material paper is used in high-temperature environments above 250°C in ultra-high-speed aerospace equipment.

[0021] The design concept of this invention is as follows: Short-cut fiber wet paper without binder has low strength and is prone to breakage during transfer, making continuous production impossible. By using PBO pulp fiber and PBO micro / nano fibers as reinforcing components in the web layer of the base paper, the strength of the wet paper web is significantly improved, solving the problems of low wet paper strength and easy breakage during transfer that prevent continuous production when using only short-cut fibers. Furthermore, since PBO fiber is an aromatic heterocyclic polymer, its structure is easily damaged under ultraviolet radiation, leading to a significant decrease in mechanical properties. To address this issue, this invention employs a unique structural design, utilizing a double-layer headbox forming technology to prepare a base paper with an "asymmetric" structure (one side is a "web surface" containing PBO fibers, and the other side is a "blanket surface" of pure short-cut fibers). During the lamination stage, the "web surfaces" of the two base papers are bonded together. This protects the UV-sensitive PBO fibers within the inner middle layer of the composite paper, while the exposed upper and lower surfaces are composed of more weather-resistant short-cut fibers and resin. It not only achieves high temperature resistance for honeycomb core paper, but also improves the material's environmental resistance and manufacturing processability, providing key basic material support for advanced aerospace equipment such as hypersonic aircraft and spacecraft.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, all the raw materials are fibers and resins with a temperature resistance of >250℃. Through the high temperature pressing process, the product can work stably for a long time in an environment above 250℃. Through the composite structure design of "mesh to mesh", the ultraviolet-sensitive PBO fiber is protected inside the material, which effectively improves the product's resistance to ultraviolet aging and extends its service life in complex environments.

[0023] (2) In this invention, PBO pulp fiber and PBO micro-nano fiber are introduced as wet reinforcing agents, which significantly improves the strength of wet paper web, solves the problem of paper breakage caused by insufficient wet paper strength during production, and realizes stable and continuous large-scale production.

[0024] (3) The method for preparing high-temperature resistant honeycomb core paper of the present invention is simple, the raw materials are readily available, the production cost is low, and it is suitable for large-scale industrial production. It does not use other polluting chemical additives, thus reducing environmental pollution. Detailed Implementation

[0025] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below in conjunction with the specification and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0026] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0027] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0028] Example 1 A method for preparing high-temperature resistant honeycomb core paper includes the following steps: (1) PBO fibers were fibrillated by a pulping machine to obtain micro-nano fibers with a diameter of about 100 nm and a length of about 1000 μm.

[0029] (2) A web surface slurry was prepared by mixing PBO micro / nano fibers, 3mm chopped carbon fibers, and 0.3mm PBO pulp fibers in a mass ratio of 3:75:22, with a slurry concentration of 1‰. The carpet surface slurry was composed of 3mm chopped carbon fibers with a slurry concentration of 1‰. Among them, the micro / nano fibers, chopped carbon fibers, and pulp fibers are fibers with a temperature resistance of >250℃.

[0030] (3) The slurry for the wire and the slurry for the mat are further diluted by 0.2‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the slurry flow rate to the forming wire running speed is controlled to be 1. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and mat surfaces is 10 g / m. 2 .

[0031] (4) A cyanate ester resin with a solid content of 50% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 15%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 5kN / m, the second press pressure is 10kN / m, and the third press pressure is 35kN / m. The paper is then dried and wound to obtain the base paper.

[0032] (5) A cyanate resin with a solid content of 75% is applied to the prepared base paper mesh, and the amount of glue is controlled at about 15%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0033] Example 2 A method for preparing high-temperature resistant honeycomb core paper includes the following steps: (1) PBO fibers were fibrillated by using a pulping machine to obtain micro-nano fibers with a diameter of about 50 nm and a length of about 100 μm.

[0034] (2) A web surface slurry was prepared by mixing PBO micro / nano fibers, 6mm chopped carbon fibers, and 0.7mm PBO pulp fibers in a mass ratio of 15:50:35, with a slurry concentration of 1‰. The carpet surface slurry was composed of 6mm chopped carbon fibers with a slurry concentration of 1‰. Among them, the micro / nano fibers, chopped carbon fibers, and pulp fibers are fibers with a temperature resistance of >250℃.

[0035] (3) The sizing agents for the wire and the fabric are further diluted by 0.05‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the sizing flow rate to the forming wire running speed is controlled to be 0.9. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and fabric surfaces is 10 g / m. 2 .

[0036] (4) A cyanate ester resin with a solid content of 10% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 5%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 10kN / m, the second press pressure is 25kN / m, and the third press pressure is 50kN / m. The paper is then dried and wound to obtain the base paper.

[0037] (5) A cyanate resin with a solid content of 50% is applied to the prepared base paper mesh, and the amount of glue is controlled at about 5%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0038] Example 3 A method for preparing high-temperature resistant honeycomb core paper includes the following steps: (1) PBO fibers were fibrillated by using a pulping machine to obtain micro-nano fibers with a diameter of about 300 nm and a length of about 500 μm.

[0039] (2) A web surface slurry was prepared by mixing PBO micro / nano fibers, 9mm chopped carbon fibers, and 1.2mm PBO pulp fibers in a mass ratio of 9:65:26, with a slurry concentration of 1‰. The carpet surface slurry was composed of 9mm chopped carbon fibers with a slurry concentration of 1‰. Among them, the micro / nano fibers, chopped carbon fibers, and pulp fibers are fibers with a temperature resistance of >250℃.

[0040] (3) The sizing agents for the wire and the fabric are further diluted by 0.12‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the sizing flow rate to the forming wire running speed is controlled to be 0.95. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and fabric surfaces is 10 g / m. 2 .

[0041] (4) A cyanate ester resin with a solid content of 10% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 10%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 8kN / m, the second press pressure is 17kN / m, and the third press pressure is 42kN / m. The paper is then dried and wound to obtain the base paper.

[0042] (5) A cyanate resin with a solid content of 65% is applied to the prepared base paper mesh, and the amount of glue is controlled at about 10%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0043] Example 4 A method for preparing high-temperature resistant honeycomb core paper includes the following steps: (1) PBO fibers were fibrillated by using a pulping machine to obtain micro-nano fibers with a diameter of about 300 nm and a length of about 500 μm.

[0044] (2) A web surface slurry was prepared by mixing PBO micro / nano fibers, 9mm chopped carbon fibers, and 1.2mm PBO pulp fibers in a mass ratio of 9:65:26, with a slurry concentration of 1‰. The carpet surface slurry was composed of 9mm chopped glass fibers with a slurry concentration of 1‰. Among them, the micro / nano fibers, chopped carbon fibers, and pulp fibers were fibers with a temperature resistance >250℃.

[0045] (3) The sizing agents for the wire and the fabric are further diluted by 0.12‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the sizing flow rate to the forming wire running speed is controlled to be 0.95. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and fabric surfaces is 10 g / m. 2 .

[0046] (4) A cyanate ester resin with a solid content of 30% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 10%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 8kN / m, the second press pressure is 17kN / m, and the third press pressure is 42kN / m. The paper is then dried and wound to obtain the base paper.

[0047] (5) A cyanate resin with a solid content of 65% is applied to the prepared base paper mesh, and the amount of glue is controlled at about 10%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0048] Example 5 A method for preparing high-temperature resistant honeycomb core paper includes the following steps: (1) PBO fibers were fibrillated by using a pulping machine to obtain micro-nano fibers with a diameter of about 300 nm and a length of about 500 μm.

[0049] (2) A web surface sizing agent was prepared by mixing PBO micro / nano fibers, 6mm chopped carbon fibers, and 1.2mm PBO pulp fibers in a mass ratio of 9:65:26, with a sizing agent concentration of 1‰. The carpet surface sizing agent was composed of 6mm chopped ceramic fibers with a sizing agent concentration of 1‰. Among them, the micro / nano fibers, chopped carbon fibers, and pulp fibers were fibers with a temperature resistance of >250℃.

[0050] (3) The sizing agents for the wire and the fabric are further diluted by 0.12‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the sizing flow rate to the forming wire running speed is controlled to be 0.95. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and fabric surfaces is 10 g / m. 2 .

[0051] (4) A bismaleimide resin with a solid content of 30% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 10%. After high vacuum suction, it is transferred to the press section. The first press pressure is 8kN / m, the second press pressure is 17kN / m, and the third press pressure is 42kN / m. The paper is then dried and wound to obtain the base paper.

[0052] (5) A bismaleimide resin with a solid content of 65% is applied to the prepared base paper mesh surface, and the amount of glue is controlled at about 10%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0053] Comparative Example 1 (1) PBO fibers were fibrillated by a pulping machine to obtain micro-nano fibers with a diameter of about 100 nm and a length of about 1000 μm.

[0054] (2) The mesh slurry is composed of 3mm short-cut carbon fibers and the slurry concentration is 1‰; the carpet slurry is composed of 3mm short-cut carbon fibers and the slurry concentration is 1‰.

[0055] (3) The slurry for the wire and the slurry for the mat are further diluted by 0.2‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the slurry flow rate to the forming wire running speed is controlled to be 1. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and mat surfaces is 10 g / m. 2 .

[0056] (4) A cyanate ester resin with a solid content of 50% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 15%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 5kN / m, the second press pressure is 10kN / m, and the third press pressure is 35kN / m. The paper is then dried and wound to obtain the base paper.

[0057] (5) A cyanate resin with a solid content of 75% is applied to the prepared base paper mesh, and the amount of glue is controlled at about 15%. Then the mesh surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0058] Comparative Example 2 (1) PBO fibers were fibrillated by using a pulping machine to obtain micro-nano fibers with a diameter of about 50 nm and a length of about 100 μm.

[0059] (2) The mesh slurry was prepared by mixing PBO micro-nano fiber, 6mm short carbon fiber and 0.7mm PBO pulp fiber in a mass ratio of 15:50:35, and the concentration of the mixed slurry was 1‰; the carpet slurry was composed of 6mm short carbon fiber and the slurry concentration was 1‰.

[0060] (3) The sizing agents for the wire and the fabric are further diluted by 0.05‰ and pumped to the double-layer headbox via pipelines. Then, the paper is formed, and the ratio of the sizing flow rate to the forming wire running speed is controlled to be 0.9. After dewatering, a wet paper web is formed on the wire. The basis weight of both the wire and fabric surfaces is 10 g / m. 2 .

[0061] (4) A cyanate ester resin with a solid content of 10% is applied to the surface of the wet paper web, and the amount of sizing is controlled at 5%. After high vacuum suction, the paper is transferred to the press section. The first press pressure is 10kN / m, the second press pressure is 25kN / m, and the third press pressure is 50kN / m. The paper is then dried and wound to obtain the base paper.

[0062] (5) A cyanate resin with a solid content of 50% is applied to the prepared base paper blanket surface, and the amount of glue is controlled at about 5%. Then the blanket surfaces of the two layers of paper are bonded together and continuously laminated. After drying, it is rolled at 350℃ to obtain a high-temperature resistant honeycomb core material paper.

[0063] Comparative Example 3 The same formula is used for the pulp on both the mesh and the carpet surfaces: PBO micro / nano fibers, 6mm chopped carbon fibers, and 0.7mm PBO pulp fibers in a ratio of 15:50:35, meaning both surfaces contain PBO fibers. The remaining steps are the same as in Example 2.

[0064] The mechanical properties, high temperature resistance, and UV resistance of the paper prepared in the examples and comparative examples were tested, and the test results are shown in Table 1 below.

[0065] Table 1: Performance test results of paper prepared in the examples and comparative examples

[0066] Examples 1-5 all successfully prepared high-temperature resistant paper, and the strength retention rate after high temperature or ultraviolet aging was extremely high (>97%), proving that the honeycomb core material paper prepared in this invention has high temperature resistance, excellent anti-ultraviolet aging performance and sufficient wet strength.

[0067] Compared with Example 1, Comparative Example 1 used only carbon fiber for the pulp on the wire and carpet surfaces, without using PBO pulp and PBO micro / nano fibers. Due to the low wet strength, it could not be transferred from the wire section to the press section, resulting in production interruption and no sample was obtained. This demonstrates the key role of PBO pulp and micro / nano fibers in improving wet paper web strength and achieving continuous production in this invention.

[0068] Compared with Example 2, Comparative Example 2, in the double-layer composite process, combines the carpet surface with the carpet surface, that is, the side containing PBO pulp and PBO micro-nano fibers faces outwards. After ultraviolet aging treatment, the performance retention rate is relatively low.

[0069] Compared with Example 2, the pulp of both the wire mesh and the carpet surface in Comparative Example 3 is composed of PBO micro-nano fibers, 6mm chopped carbon fibers and 0.7mm PBO pulp fibers. Due to the high mass percentage of PBO micro-nano fibers and pulp fibers in the product, the paper has high tensile strength, but due to the high PBO fiber content, the UV aging resistance is poor.

[0070] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. However, it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A type of high-temperature resistant honeycomb core material paper, characterized in that, It has a three-layer composite structure, including two outer layers and one middle layer; The two outer layers have the same composition, both consisting of high-temperature resistant short-cut fibers and high-temperature resistant resin; The intermediate layer is located between the two outer layers, and its components include high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, high-temperature resistant chopped fibers, and high-temperature resistant resin. The high-temperature resistant micro / nano fiber is fibrillated PBO fiber; the high-temperature resistant pulp fiber is PBO pulp fiber.

2. The high-temperature resistant honeycomb core material paper according to claim 1, characterized in that, The high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers are all fibers with a temperature resistance of >250℃.

3. The high-temperature resistant honeycomb core material paper according to claim 1, characterized in that, The mass ratio of high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers and high-temperature resistant short-cut fibers in the intermediate layer is 3-15:15-35:50-75.

4. The high-temperature resistant honeycomb core material paper according to claim 1, characterized in that, The high-temperature resistant micro / nano fibers have a diameter of 50–500 nm and a length of 100–1000 μm; the high-temperature resistant pulp fibers have a length of 0.3–1.2 mm; and the high-temperature resistant chopped fibers are selected from at least one of carbon fiber, glass fiber, or ceramic fiber, with a length of 3–9 mm.

5. The high-temperature resistant honeycomb core material paper according to claim 1, characterized in that, The high-temperature resistant resin is selected from one or both of bismaleimide resin and cyanate ester resin.

6. A method for preparing high-temperature resistant honeycomb core paper as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Prepare a web surface sizing agent by mixing high-temperature resistant micro-nano fibers, high-temperature resistant pulp fibers, and high-temperature resistant chopped fibers in a specific ratio; prepare a carpet surface sizing agent by mixing high-temperature resistant chopped fibers. S2. The wire surface slurry and the carpet surface slurry prepared in S1 are evenly fed onto the wire through a double-layer headbox and dewatered at the wire section to form a wet paper web; S3. The base paper is obtained by coating the surface of the wet paper web obtained in S2 with a high-temperature resistant resin, and then pressing, drying and curling. S4. The wire mesh of the base paper obtained in S3 is coated with high-temperature resistant resin, and then the wire meshes of the two base papers are laminated and pressed at high temperature to obtain high-temperature resistant honeycomb core material paper.

7. The method for preparing high-temperature resistant honeycomb core paper according to claim 6, characterized in that, In S2, the upper layer of the double-layer headbox is used to distribute the slurry on the carpet surface, and the lower layer is used to distribute the slurry on the mesh surface. The forming concentration of the carpet surface slurry or the mesh surface slurry is 0.05 to 0.2‰, and the ratio of the slurry flow rate to the forming mesh running speed is 0.9 to 1.

8. The method for preparing high-temperature resistant honeycomb core paper according to claim 6, characterized in that, In S3, the pressing process adopts a three-pressure gradient pressing method, with the first pressure being 5-10 kN / m, the second pressure being 10-25 kN / m, and the third pressure being 35-50 kN / m.

9. The method for preparing high-temperature resistant honeycomb core paper according to claim 6, characterized in that, In S3, the solid content of the high-temperature resistant resin is 10-50%, and the amount of sizing is 5-15% of the weight of the base paper; In S4, the solid content of the high-temperature resistant resin is 50-75%, and the amount of sizing is 5-15% of the weight of the base paper.

10. The application of a high-temperature resistant honeycomb core material paper as described in any one of claims 1 to 5 in aerospace equipment, characterized in that, The high-temperature resistant honeycomb core material paper is used in high-temperature environments above 250°C in ultra-high-speed aerospace equipment.

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