High-compactness meta-aramid paper as well as preparation method and application thereof

Abstract

The invention provides high-compactness meta-aramid paper and a preparation method and application thereof, and the preparation method comprises the following steps: (1) mixing an organic solvent, an adhesive and a cosolvent to obtain a mixed solution; (2) soaking meta-aramid paper in the mixed solution for the first time, then soaking the meta-aramid paper in deionized water for the second time, and then drying and hot-pressing the meta-aramid paper to obtain the high-compactness meta-aramid paper. The preparation method comprises the following steps: soaking meta-aramid paper in a mixed solution containing an organic solvent, an adhesive and a cosolvent to swell the surfaces of aramid chopped fibers and partially dissolve fibrids, and then soaking the meta-aramid paper in deionized water to remove the organic solvent, so that the swelled / dissolved fibers are partially fused to obtain the meta-aramid paper. And carrying out hot pressing to obtain the meta-aramid paper with high compactness, high insulation and excellent mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of meta-aramid paper manufacturing, and relates to high-density meta-aramid paper and a preparation method and application thereof. Background Art

[0002] Meta-aramid paper is a high-performance paper-based material obtained by wet forming aramid short fibers and aramid precipitated fibers and then hot pressing. It has excellent properties such as light weight, flame retardancy, insulation, high temperature resistance, and corrosion resistance, and has been widely used in electrical insulation products and aerospace fields. In recent years, with the expansion of the application field of aramid composite materials and the surge in market demand, the performance requirements for aramid paper have become higher and higher, so the high performance of aramid paper-based materials has always been a research hotspot in this field.

[0003] The mechanical strength of meta-aramid paper mainly depends on the strength of the fiber itself and the interaction between the fibers. The meta-aramid paper obtained by traditional wet papermaking is loose and porous, with a smooth and chemically inert fiber surface. There is no chemical bonding between the short-cut fibers and the precipitated fibers inside the paper, and only a small amount of bond bonding, which makes it difficult to form a dense interwoven structure, resulting in low bonding strength between the fibers, greatly limiting the mechanical properties and insulation properties of the paper. Therefore, improving the density of meta-aramid paper and regulating the void structure of meta-aramid paper are of great significance to the high performance and application expansion of meta-aramid paper.

[0004] Constructing a dense structure of aramid paper is an effective way to improve the insulation properties and mechanical strength of meta-aramid paper. Common methods include hot pressing reinforcement, resin filling and aramid nanofiber regulation. Regulating the pressure and temperature of the hot pressing section can soften or partially melt the fibers, densify the structure of the paper, and enhance the bonding force between the fibers. However, the hot pressing process requires special equipment, and the temperature, line pressure and time parameters are complex to control, and it consumes a lot of energy and is costly. Resin can increase the bonding force between fibers, but a large amount of resin entering the interior of the paper will cause the paper to become brittle and lose flexibility, limiting its application. Aramid nanofiber filling can significantly improve the matrix interface bonding strength, but its preparation process has problems such as solvent removal and long protonation reduction cycle, making it difficult to industrialize. Therefore, there are still huge challenges in developing a simple and efficient method for enhancing the interface of meta-aramid paper. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-density meta-aramid paper and a preparation method and application thereof.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing high-density meta-aramid paper, the preparation method comprising the following steps:

[0008] (1) mixing an organic solvent, an adhesive, and a co-solvent to obtain a mixed solution;

[0009] (2) soaking the meta-aramid paper in the mixed solution for the first time to displace the air in the paper, taking it out, and then soaking it in deionized water for the second time, followed by drying and hot pressing to obtain the high-density meta-aramid paper.

[0010] The present invention impregnates aramid paper with an organic solvent to make the surface of aramid chopped fibers swell and the fibrils partially dissolve, giving the fiber molecular chains a certain activity ability, enhancing the interaction between the aramid fiber molecular chains, further adjusting the solvent environment to make the dissolved fibrils precipitate, and adhere to the fiber crystallization area, thereby improving the strength of the aramid paper. The present invention proposes to immerse the meta-aramid paper in a mixed solution of an organic solvent, an adhesive, and a co-solvent to make the aramid fibers swell / dissolve, further remove the solvent to make the swollen / dissolved fibers partially fuse, and then obtain meta-aramid paper with high density, high insulation and excellent mechanical properties after high temperature hot pressing.

[0011] During the impregnation process, the solvent swells and dissolves the fibers. The larger specific surface area of ​​the precipitated fibrils allows the solvent to dissolve them well, so that they adhere to the swollen short fibers. The polar solvent dissolves the polymer on the fiber surface or swells some of the polymer segments. As the drying progresses and the solvent is removed, the dissolved polymer acts as an adhesive, causing the fibers to bond to each other. The solvent treatment increases the interface bonding between the short fibers and the precipitated fibrils, forming a more uniform structure for the paper, thereby improving the mechanical properties.

[0012] Based on the above content, the present invention explores the influence of the type of organic solvent on the structure and properties of meta-aramid paper, and studies the influence of impregnation treatment on the mechanical properties and insulation properties of meta-aramid paper.

[0013] In the present invention, the "high density" in the high density meta-aramid paper refers to the density of the meta-aramid paper being ≥ 0.86 g / m 3 .

[0014] Preferably, the organic solvent includes any one of N,N-dimethylacetamide (DMAC), dichloromethane (DCM), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO), or a combination of at least two thereof.

[0015] Preferably, the adhesive comprises polyetherimide (PEI). PEI, as an adhesive, can enhance the bonding strength between aramid fibers.

[0016] Preferably, the co-solvent is an alkaline substance.

[0017] Preferably, the co-solvent includes potassium hydroxide (KOH) and / or sodium hydroxide (NaOH). Alkali (KOH or NaOH, etc.) as a co-solvent can accelerate the swelling / dissolution of aramid fibers, but if there is residual alkali in the aramid paper, the hygroscopicity of the paper will be enhanced and the wet strength will be reduced, which is not conducive to the long-term use of meta-aramid paper.

[0018] Preferably, the amount of the adhesive added is 5-20 times the mass of the meta-aramid paper in step (2), for example, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 11 times, 12 times, 13 times, 14 times, 15 times, 16 times, 17 times, 18 times, 19 times, 20 times, etc.

[0019] Preferably, based on the total mass of the organic solvent and the adhesive as 100%, the amount of the adhesive is 2% to 5% (ie, the solid content is 2% to 5%), for example, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0020] Preferably, the amount of the co-solvent added is 0.02% to 0.05% of the mass of the meta-aramid paper in step (2), for example, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, etc.

[0021] Preferably, the first soaking time in step (2) is 20 to 40 seconds, for example, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, etc.

[0022] Preferably, the drying in step (2) is carried out in a forced air drying oven.

[0023] Preferably, the drying temperature in step (2) is 100-110°C, for example, 100°C, 105°C, 110°C, etc.

[0024] Preferably, the drying time in step (2) is 20 to 40 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0025] Preferably, the hot pressing in step (2) is carried out in a roller hot press.

[0026] Preferably, the temperature of the hot pressing in step (2) is 270-300°C, for example, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, etc.

[0027] Preferably, the hot pressing pressure in step (2) is 8 to 15 MPa, for example, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, etc.

[0028] Preferably, the speed of the hot pressing in step (2) is 3 to 10 m / min, for example, 3 m / min, 4 m / min, 5 m / min, 6 m / min, 7 m / min, 8 m / min, 9 m / min, 10 m / min, etc.

[0029] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0030] (1) mixing an organic solvent, an adhesive, and a co-solvent to obtain a mixed solution;

[0031] (2) soaking the meta-aramid paper in the mixed solution for the first time to replace the air in the paper, taking it out after 20 to 40 seconds, and then soaking it in deionized water for the second time to remove the organic solvent, and then drying it in a blast drying oven at 100 to 110° C. for 20 to 40 minutes to remove the residual organic solvent and moisture, and then introducing the meta-aramid paper into a roller hot press for hot pressing at a temperature of 270 to 300° C., a pressure of 8 to 15 MPa, and a speed of 3 to 10 m / min to obtain the high-density meta-aramid paper.

[0032] In a second aspect, the present invention provides a high-density meta-aramid paper, wherein the high-density meta-aramid paper is prepared by the preparation method described in the first aspect.

[0033] Preferably, the density of the high-density meta-aramid paper is ≥ 0.86 g / m 3 , for example 0.86g / m 3 , 0.87g / m 3 , 0.88g / m 3 , 0.89g / m 3 , 0.90g / m 3 , 0.91g / m 3 , 0.92g / m 3 , 0.93g / m 3 , 0.94g / m 3 , 0.95g / m 3 wait.

[0034] In a third aspect, the present invention provides an application of the high-density meta-aramid paper as described in the second aspect in aerospace, electrical insulation, new energy vehicles, and rail transit.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] The invention soaks the meta-aramid paper in a mixed solution containing an organic solvent, an adhesive and a co-solvent to swell the surface of the aramid chopped fibers and partially dissolve the precipitated fibers, then soaks the mixed solution in deionized water to remove the organic solvent, partially fuses the swollen / dissolved fibers, and then performs hot pressing to obtain the meta-aramid paper with high density, high insulation and excellent mechanical properties. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0038] Unless otherwise specified, the materials involved in the following specific implementations of the present invention are as follows:

[0039] (1) Meta-aramid paper: Chaomeis New Materials Co., Ltd., model: X630-0.05;

[0040] Among them, the meta-aramid paper (X630-0.05) is prepared by mixing precipitated fibers and short-cut fibers in a mass ratio of 1:1, with a paper thickness of 0.05 mm and a basis weight (i.e., gram weight) of 40 g / m 2 , tightness is 0.80g / m 3 , longitudinal tensile strength is 4.29kN / m, transverse tensile strength is 1.56kN / m, and dielectric strength is 15.7KV / mm;

[0041] (2) N,N-dimethylacetamide (DMAC): Jinan Mingbang Chemical Co., Ltd., analytical grade AR, active ingredient content ≥ 99.5%;

[0042] (3) N,N-dimethylformamide (DMF): Nantong Runfeng Petrochemical Co., Ltd., analytical grade AR, active ingredient content ≥ 99.9%;

[0043] (4) Dimethyl sulfoxide (DMSO): Shandong Nabaichuan Chemical Sales Co., Ltd., analytical grade AR, active ingredient content ≥ 99.9%;

[0044] (5) Polyetherimide (PEI): Dongguan Zhongming Plastic Co., Ltd., model: XH42604SEVJH;

[0045] (6) Potassium hydroxide (KOH): Tianjin Jinhui Taiya Chemical Reagent Co., Ltd., analytical grade AR, active ingredient content ≥ 85%;

[0046] (7) Polybenzimidazole (PBI): Shanghai Huifei Chemical Co., Ltd., model: DURATRON CU60.

[0047] Example 1

[0048] In this embodiment, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0049] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0050] Step 2: Add 800 ml of DMAC to a beaker with a maximum range of 1000 ml, dissolve PEI in DMAC, and add 0.03% by mass of KOH (relative to the absolute dry meta-aramid paper) in an amount of 1.08 mg to obtain a mixed solution;

[0051] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0052] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0053] Example 2

[0054] In this embodiment, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0055] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0056] Step 2: Add 800 ml of DMAC to a beaker with a maximum range of 1000 ml, dissolve PEI in DMAC, and add 0.03% by mass of KOH (relative to the absolute dry meta-aramid paper) in an amount of 1.08 mg to obtain a mixed solution;

[0057] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0058] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 280° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0059] Example 3

[0060] In this embodiment, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0061] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0062] Step 2: Add 800 ml of DMAC to a beaker with a maximum range of 1000 ml, dissolve PEI in DMAC, and add 0.05% by mass of KOH (relative to the absolute dry meta-aramid paper) in an amount of 1.8 mg to obtain a mixed solution;

[0063] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0064] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0065] Example 4

[0066] In this embodiment, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0067] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0068] Step 2: Add 800 ml of DMF to a beaker with a maximum range of 1000 ml, dissolve PEI in DMF, and add 0.03% by mass of KOH (relative to the absolute dry meta-aramid paper) in an amount of 1.08 mg to obtain a mixed solution;

[0069] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0070] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0071] Example 5

[0072] In this embodiment, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0073] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0074] Step 2: Add 800 ml of DMSO to a beaker with a maximum range of 1000 ml, dissolve PEI in DMSO to a solid content of 3%, add 0.03% by mass of KOH (relative to absolute dry meta-aramid paper), and add 1.08 mg to obtain a mixed solution;

[0075] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0076] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0077] Comparative Example 1

[0078] In this comparative example, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0079] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0080] Step 2: Add 800 ml of DMAC to a beaker with a maximum range of 1000 ml, add 0.03% by mass of KOH (relative to the absolute dry meta-aramid paper), and add 1.08 mg to obtain a mixed solution;

[0081] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0082] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0083] Comparative Example 2

[0084] In this comparative example, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0085] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0086] Step 2: Add 800 ml of DMAC into a beaker with a maximum range of 1000 ml, dissolve PEI in DMAC, and obtain a mixed solution with a solid content of 3%;

[0087] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0088] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0089] Comparative Example 3

[0090] In this comparative example, a method for preparing high-density meta-aramid paper is provided, which specifically comprises the following steps:

[0091] Step 1: Cut the meta-aramid paper into 300mm×300mm size;

[0092] Step 2: Add 800 ml of DMAC to a beaker with a maximum range of 1000 ml, dissolve polybenzimidazole (PBI) in DMAC, with a solid content of 3%, add 0.05% by mass of KOH (relative to absolute dry meta-aramid paper), and add 1.8 mg to obtain a mixed solution;

[0093] Step 3: soak the meta-aramid paper in the mixed solution in step 2, take out the aramid paper after 30 seconds, soak it in deionized water to remove the solvent, and then dry it in a blast drying oven at 105° C. for 30 minutes to remove the residual solvent and moisture;

[0094] Step 4: introducing the aramid paper of step 3 into a roller hot press for hot pressing, and the hot pressing conditions are: temperature 270° C., pressure 10 MPa, speed 5 m / min, to obtain the high-density meta-aramid paper.

[0095] The performance of the high-density meta-aramid paper prepared in the examples and comparative examples was tested, and the testing method was as follows:

[0096] (1) Thickness

[0097] Reference national standard: GB / T 451.3-2002 Determination of thickness of paper and paperboard;

[0098] (2) Weight

[0099] Reference national standard: GB / T 451.2-2002 Determination of the basis weight of paper and paperboard;

[0100] (3) Tightness

[0101] Reference national standard: GB / T 451.3-2002 Determination of thickness of paper and paperboard - 3.4 Single layer tightness;

[0102] (4) Tensile strength

[0103] Reference national standard: GB / T12914-2018 Determination of tensile strength of paper and paperboard;

[0104] (5) Dielectric strength

[0105] Reference national standard: GB / T 1408.1-2006 Electric strength test method for insulating materials.

[0106] The performance test results are shown in Table 1.

[0107] Table 1

[0108]

[0109] As can be seen from Table 1, the meta-aramid paper prepared by the preparation method of the embodiment of the present invention achieves the swelling / dissolution of the meta-aramid paper by adding an organic solvent / a specific adhesive / a co-solvent, and improves its density and mechanical properties. The prepared meta-aramid paper has a thickness of 0.043-0.047 mm and a gram weight of 39.8-40.3 g / m 2 , tightness ≥ 0.86g / m 3 , longitudinal tensile strength ≥6.14kN / m, transverse tensile strength ≥1.94kN / m.

[0110] By comparing Example 1 with Comparative Example 1, it can be seen that the present invention can obtain the technical effect of high mechanical properties by adopting an adhesive, while when the adhesive is lacking, it is impossible to obtain meta-aramid paper with excellent mechanical properties.

[0111] By comparing Example 1 with Comparative Example 2, it can be seen that the present invention can obtain the technical effect of high density by adopting a co-solvent, while when the co-solvent is lacking, it is impossible to obtain meta-aramid paper with high density.

[0112] By comparing Example 3 with Comparative Example 3, it can be seen that the present invention can obtain the technical effect of enhancing the bonding strength between aramid fibers by comparing different adhesives by using polybenzimidazole (PBI) instead of polyetherimide (PEI), while when polyetherimide (PEI) is replaced by polybenzimidazole (PBI), the obtained meta-aramid paper cannot simultaneously achieve excellent mechanical properties and high density.

[0113] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the high-density meta-aramid paper and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing high-density meta-aramid paper, characterized in that: The preparation method comprises the following steps: (1) mixing an organic solvent, an adhesive, and a co-solvent to obtain a mixed solution; (2) soaking the meta-aramid paper in the mixed solution for the first time, and then soaking it in deionized water for the second time, followed by drying and hot pressing to obtain the high-density meta-aramid paper.

2. The preparation method according to claim 1, characterized in that: The organic solvent includes any one of N,N-dimethylacetamide, dichloromethane, N,N-dimethylformamide, and dimethyl sulfoxide, or a combination of at least two thereof; Preferably, the adhesive comprises polyetherimide; Preferably, the co-solvent is an alkaline substance; Preferably, the co-solvent comprises potassium hydroxide and / or sodium hydroxide.

3. The preparation method according to claim 1 or 2, characterized in that: The amount of the adhesive added is 5-20 times the mass of the meta-aramid paper in step (2); Preferably, based on the total mass of the organic solvent and the adhesive being 100%, the amount of the adhesive used is 2% to 5%.

4. The preparation method according to any one of claims 1 to 3, characterized in that The amount of the co-solvent added is 0.02% to 0.05% of the mass of the meta-aramid paper in step (2).

5. The preparation method according to any one of claims 1 to 4, characterized in that: The first soaking time in step (2) is 20 to 40 seconds.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The drying in step (2) is carried out in a blast drying oven; Preferably, the drying temperature in step (2) is 100-110°C; Preferably, the drying time in step (2) is 20 to 40 minutes.

7. The preparation method according to any one of claims 1 to 6, characterized in that The hot pressing in step (2) is carried out in a roller hot press; Preferably, the temperature of the hot pressing in step (2) is 270-300°C; Preferably, the hot pressing pressure in step (2) is 8 to 15 MPa; Preferably, the speed of the hot pressing in step (2) is 3 to 10 m / min.

8. A preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) mixing an organic solvent, an adhesive, and a co-solvent to obtain a mixed solution; (2) soaking the meta-aramid paper in the mixed solution for the first time, taking it out after 20 to 40 seconds, and then soaking it in deionized water for the second time to remove the organic solvent, and then drying it in a blast drying oven at 100 to 110° C. for 20 to 40 minutes to remove the residual organic solvent and moisture, and then introducing the meta-aramid paper into a roller hot press for hot pressing at a temperature of 270 to 300° C., a pressure of 8 to 15 MPa, and a speed of 3 to 10 m / min to obtain the high-density meta-aramid paper.

9. A high-density meta-aramid paper, characterized in that: The high-density meta-aramid paper is prepared by the preparation method according to any one of claims 1 to 8; Preferably, the density of the high-density meta-aramid paper is ≥ 0.86 g / m 3 .

10. Application of the high-density meta-aramid paper according to claim 9 in aerospace, electrical insulation, new energy vehicles, and rail transportation.

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