CN108824067A - A kind of p-aramid paper and preparation method thereof - Google Patents

Abstract

The invention provides a preparation method of para-aramid paper, comprising: forming the para-aramid nanofiber material liquid on the net to obtain wet paper; dehydrating the wet paper by multi-stage buffer pressing to obtain dehydrated wet paper The dehydrated wet paper is sequentially subjected to multi-stage low-temperature drying and tension-assisted drying for drying and molding to obtain para-aramid paper; the method of online molding is: sizing the para-aramid nanofiber material liquid and then filtering , forming a wet paper embryo on the surface of the forming wire; vacuuming the lower surface of the wet paper embryo and then dehydrating the upper surface of the wet paper embryo with an upper top wire former for two-way dehydration to obtain wet paper. The present invention adopts a special net forming process, a multi-stage buffer pressing process, a multi-stage low-temperature drying process and a tension-assisted drying process to prepare the aramid paper with good uniformity, excellent mechanical properties and insulating properties. The invention also provides a para-aramid paper.

Description

A kind of para-aramid fiber paper and preparation method thereof

technical field

The invention relates to the technical field of film materials, in particular to a para-aramid paper and a preparation method thereof.

Background technique

Para-aramid paper (PAP) is a high-performance special film material, which has the advantages of high strength and high modulus, excellent dimensional stability, excellent electrical insulation performance, chemical corrosion resistance, and light weight. It can be used as structural materials, insulating materials , wave penetration and filter materials are widely used in aerospace, military equipment, electronic appliances and other industries.

At present, the raw materials used to prepare PAP are mainly para-aramid short fibers, pulp or precipitated fibers, and sometimes meta-aramid fibers or other thermoplastic resins are added as reinforcing agents. The process of papermaking is also relatively complicated. Generally, the fiber needs to be beaten into a slurry through a special process, and a dispersant needs to be added to improve the dispersion and stability of the slurry. Even so, it is difficult to prepare PAP with stable performance. Because the thickness of PAP is generally tens of microns (the thickness of some PAPs for special purposes is more than 100 microns), while the diameter of para-aramid short fibers is about 10 microns, and the main structural size of pulp and precipitated fibers is also several hundred nanometers Once the slurry is dispersed unevenly, it will easily cause uneven PAP, and then make the performance of PAP unstable. In addition, the addition of meta-aramid fibers and dispersing aids will also deteriorate the performance of PAP. Meta-aramid fiber has high hygroscopicity, which will cause the dimensional stability of PAP to decrease under high humidity, and it is difficult to meet the requirements of high-precision products. The addition of dispersants is not conducive to the dielectric properties of PAP on the one hand, and on the other hand, it will also generate a large amount of waste water, which will pollute the environment or increase production costs.

Moreover, in the papermaking process of using all-nanofibers, there are difficulties such as difficult dehydration, low wet strength of the prepared wet paper, and large dimensional shrinkage during the drying process, which seriously affects the performance of the prepared para-aramid paper. Therefore, developing a high-performance PAP preparation process has become an urgent problem to be solved by those skilled in the art.

Contents of the invention

In view of this, the object of the present invention is to provide a kind of para-aramid paper and preparation method thereof, the preparation method process of the para-aramid paper provided by the present invention is simple and the prepared para-aramid paper has excellent mechanical and electrical properties. All are excellent.

The invention provides a preparation method of para-aramid paper, comprising:

Forming the p-aramid nanofiber material liquid on the Internet to obtain wet paper;

performing multi-stage buffer press dehydration on the wet paper to obtain dehydrated wet paper;

The dehydrated wet paper is dried and calendered to obtain para-aramid paper.

In the present invention, the diameter of the para-aramid nanofiber in the para-aramid nanofiber feed solution is preferably 10-100 nm, more preferably 20-80 nm, more preferably 30-70 nm, most preferably 40-60 nm The length of the para-aramid nanofibers in the para-aramid nanofiber feed liquid is preferably 100nm-1000μm, more preferably 500nm-800μm, more preferably 800nm-600μm, and most preferably 1μm-500μm.

In the present invention, the solvent in the para-aramid nanofiber feed solution is preferably water, more preferably deionized water. In the present invention, the mass concentration of the aramid nanofiber feed solution is preferably 0.5-2.5%, more preferably 1-2%, and most preferably 1.5%.

The present invention has no special limitation on the preparation method of the para-aramid nanofiber feed solution, and the para-aramid nanofiber feed solution can be prepared by a method well known to those skilled in the art. In the present invention, the preparation method of the para-aramid nanofiber feed solution is preferably:

Under the action of chloride and polyethylene glycol, p-phenylenediamine and terephthaloyl chloride are subjected to polycondensation reaction in N-methylpyrrolidone to obtain a reaction product;

The reaction product and the solvent are mixed and crushed to obtain a mixed system;

The mixing system and water are mixed and then stirred to obtain a para-aramid nanofiber feed liquid.

In the present invention, the polycondensation reaction is preferably carried out under the protection of a protective gas such as nitrogen.

In the present invention, the chloride is preferably one or more of calcium chloride, lithium chloride and magnesium chloride; the number average molecular weight of the polyethylene glycol is preferably 2000-2500, more preferably 2100-2200 . In the present invention, the mass ratio of the chloride to polyethylene glycol is preferably (1-3):1, more preferably (1.5-2.5):1, most preferably 2:1. In the present invention, the chloride and polyethylene glycol can reduce fiber flocculation and improve molecular activity.

In the present invention, it is preferred to mix and dissolve the chloride and polyethylene glycol first, then add p-phenylenediamine to the obtained solution, and then add terephthaloyl dichloride to carry out the polycondensation reaction after it dissolves. In the present invention, the mixing and dissolving temperature is preferably 80-120°C, more preferably 90-110°C, and most preferably 100°C.

In the present invention, the polycondensation reaction is preferably carried out in an ice-water bath, and the temperature of the reaction system should not exceed 70°C. In the present invention, the polycondensation reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 1500-2500 r/min, more preferably 1800-2200 r/min, most preferably 2000 r/min.

In the present invention, the polycondensation reaction is stopped when the reaction system forms a jelly body and Weissenberg effect occurs to obtain a reaction product. In the present invention, the temperature of the polycondensation reaction is preferably -15 to 0°C, more preferably -10 to -5°C.

In the present invention, the mass volume ratio of the reaction product to the solvent is preferably 1 g:(35-45) mL, more preferably 1 g:(38-42) mL, most preferably 1 g:40 mL. In the present invention, the solvent is preferably N-methylpyrrolidone or methanol.

In the present invention, the crushing equipment is preferably a tissue grinder, and the crushing time is preferably 4-6 minutes, more preferably 5 minutes.

In the present invention, the equipment for mixing and stirring the mixing system and water is preferably a tissue pulverizer, and the stirring time is preferably 8-12 minutes, more preferably 10 minutes. In the present invention, the water is preferably deionized water.

In the present invention, after obtaining the p-aramid nanofiber feed liquid, it is preferable to repeatedly wash the p-aramid nanofiber feed liquid to remove impurities therein; the washing equipment is preferably a high-speed centrifuge or a continuous countercurrent belt washing machine.

The present invention preferably adopts the para-aramid nanofiber material solution prepared by the above-mentioned special process to prepare para-aramid paper, and the diameter of the para-aramid nanofiber in the para-aramid nanofiber material solution is lower than 100nm. In the process of preparing para-aramid paper from nanofiber material liquid, no beating is required, and no dispersant is added, and the prepared para-aramid paper has good uniformity, excellent mechanical properties and insulation properties; the preparation method is simple and the obtained Para-aramid paper has good performance.

In the present invention, the online forming is preferably using inclined wire forming or fourdrinier forming technology to spray or coat the para-aramid nanofiber material liquid onto the online forming; the forming equipment is preferably an inclined wire former or fourdrinier shaper. In the present invention, the aperture diameter of the forming mesh used in the online forming is preferably 100-300 mesh, more preferably 150-250 mesh, most preferably 200 mesh, so as to avoid the para-aramid nanofiber material liquid from leaking from the mesh . In the present invention, the method for forming online is preferably:

After sizing the para-aramid nanofiber feed solution, water is filtered, and a wet paper embryo is formed on the surface of the forming wire;

The lower surface of the wet paper embryo is subjected to vacuum suction and then the upper surface of the wet paper embryo is dehydrated by an upper top wire former to perform bidirectional dehydration to obtain wet paper.

In the present invention, the sizing preferably adopts warm water sizing; the temperature of the warm water sizing is preferably 40-60°C. In the present invention, the time for filtering water is preferably 20-30 seconds, more preferably 22-28 seconds, and most preferably 24-26 seconds. The invention adopts warm water sizing when forming pulp, which can reduce the agglomeration between fibers, improve the water filtration efficiency, reduce the water filtration time from 3 to 5 minutes to 20 to 30 seconds, greatly shorten the length of the net part, and solve the problem of all-nano alignment The problem of low speed of aramid fiber papermaking.

In the present invention, the degree of vacuum of the vacuum suction is preferably -0.01 to -0.1 MPa, more preferably -0.02 to -0.09 MPa, most preferably -0.03 to -0.06 MPa. In the present invention, it is preferable to carry out vacuum suction dehydration to the lower surface of the wet paper embryo first, and then use an upper top wire former to dehydrate the upper surface of the wet paper embryo. The dehydration method provided by the invention combines vacuum suction and upper top wire Combined with the dehydration of the wire former, the two-way dehydration of the wet paper embryo is realized. In the present invention, the vacuum degree of the vacuum suction dehydration is preferably gradually increased with the increase of the dryness of the wet paper embryo; preferably during the vacuum suction process, the dryness of the wet paper embryo increases from 3% to 5%. , the vacuum degree of vacuum suction increases from -0.01MPa to -0.1MPa.

In the present invention, the dryness of the wet paper obtained after being dehydrated by the upper top wire former is preferably 8-10%, more preferably 8.5-9.5%, and most preferably 9%.

The present invention adopts the above-mentioned special online forming process to prepare para-aramid paper. The above-mentioned online forming process adopts a dehydration method combining bottom vacuum suction and top former dehydration, and preferably adopts step-by-step vacuum suction (that is, as the wet paper embryo The increase of dryness gradually increases the vacuum degree of vacuum suction) and the dehydration method combined with the dehydration of the upper top wire former can make the fibers of the formed paper overlap tightly, and make the para-aramid paper prepared by the present invention The mechanical properties and electrical insulation properties are good.

In the present invention, since the strength of the wet paper is relatively low, the present invention preferably uses a vacuum adsorption transfer method to peel it from the forming net. The invention adopts multi-stage buffer press dehydration to dehydrate the wet paper, and this method can effectively reduce the moisture content and improve the wet strength of the dehydrated wet paper. In the present invention, the multi-stage buffer press dehydration means gradually increasing the press dewatering pressure with the increase of the dryness of the dehydrated wet paper. times. In the present invention, the number of pressing stages of the multi-stage buffer press dehydration is preferably 2-5 stages, more preferably 3-5 stages, and most preferably 4-5 stages. In the present invention, preferably as the dryness of the dehydrated wet paper increases from 10% to 15%, the pressing pressure of the multi-stage buffer press dewatering increases from 0.05 MPa to 0.35 MPa with a gradient of 0.05 MPa.

In the present invention, the multi-stage buffer press dehydration is preferably vacuum press dehydration, and the vacuum degree of the vacuum press dehydration is preferably -20 ~ -40KPa, more preferably -25 ~ -35KPa, most preferably -30KPa. In the present invention, the pressure of the high-pressure water used for cleaning the felt during the multi-stage buffer press dehydration process is preferably 1.5-2.5 MPa, more preferably 1.8-2.2 MPa, and most preferably 2 MPa.

In the present invention, the drying is multi-stage low-temperature drying and tension-assisted drying. In the present invention, the multi-stage low-temperature drying process is preferably used to dry the paper first, and then the paper is shaped, and the tension-assisted drying is used when the paper is shaped. The drying process further dries the paper. The present invention adopts this special drying process combining multi-stage low-temperature drying and tension-assisted drying to make the paper dry better, and at the same time avoid large size shrinkage during the drying process, so that the prepared para-aramid paper It has good uniformity, mechanical properties and electrical properties.

In the present invention, the multi-stage low-temperature drying refers to gradually increasing the drying temperature with the increase of paper dryness, and the number of stages of the multi-stage low-temperature drying refers to the times of increasing the drying temperature. In the present invention, the number of stages of the multi-stage low-temperature drying is preferably 6-10, more preferably 7-10, and most preferably 9-10. In the present invention, the drying method of the multi-stage low-temperature drying is preferably steam drying, heat conduction oil heating multiple sets of drying cylinders or electromagnetic heating roller drying. In the present invention, it is preferable to gradually increase the drying temperature from 60°C to 120°C as the paper dryness increases from 12% to 30%.

In the present invention, it is preferable to carry out paper setting after the dryness of the paper reaches 30%, and use tension-assisted drying when the paper is fixed, and the tension-assisted drying is preferably to use a tensioning device to stretch and set the paper while heating the paper Dry to avoid paper wrinkling and shrinkage. In the present invention, the tensioning device is preferably a drying net with a large tension force, and the tension of the tension-assisted drying is preferably 4-10KN/m, more preferably 6-9KN/m, most preferably 6.5-8KN /m. In the present invention, the method of heating and drying is preferably direct heating by using a large-diameter drying cylinder. In the present invention, the temperature of the tension-assisted drying is preferably 120-160°C, more preferably 130-150°C, and most preferably 135-145°C. In the present invention, the tension-assisted drying time is preferably 0.5-15 min, more preferably 1-10 min, more preferably 2-8 min, most preferably 3-6 min.

The present invention has no special limitation on the calendering forming method, and the conventional calendering forming technical solution well-known to those skilled in the art when preparing para-aramid paper can be used.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other examples improved or modified by those skilled in the art belong to the protection scope of the present invention.

Adopt GB/T12914-1991 " the determination method of tensile strength of paper and cardboard (constant speed stretching method) " standard, test the tensile strength and elongation of para-aramid paper that the present invention prepares; Adopt IEC60819-2: 2001 "Non-Cellulose Paper for Electrical Engineering Part 2: Test Method" tested the tearing degree of the para-aramid paper prepared by the present invention.

The electrical insulation performance of the para-aramid paper prepared by the present invention was tested by adopting the standard of GB/T1408.1-2006 "Test Method for Electric Strength of Insulating Materials Part 1: Test under Power Frequency".

The para-aramid nanofiber suspension used in the following examples of the present invention is prepared according to the following method:

Add 100 mL of N-methylpyrrolidone (NMP) to a 300 mL reactor, add 10 g of CaCl and ₅ g of polyethylene glycol (PEG) with a molecular weight of 2100 under nitrogen protection and stirring, and heat to 100 ° C to make the two or dissolved. After the CaCl ₂ and PEG are completely dissolved, use an ice-water bath to lower the solution system to 15°C, then add 4.326g of p-phenylenediamine (PPD) to dissolve, and then add 8.178g of terephthaloyl chloride (TPC) after the PPD is completely dissolved. Stir (2000r/min) for polycondensation reaction, keep an ice-water bath during the polymerization process, and keep the system temperature not exceeding 70°C; stop stirring when the above-mentioned polycondensation reaction proceeds until the system forms a jelly body and Weissenberg effect occurs, remove the ice-water bath, and take out 5 g of jelly was added to 200 mL of NMP, and the swollen jelly was broken up by rapid stirring with a tissue grinder for 5 minutes to form a uniform and stable mixed system in NMP. Add 200mL of water to the mixing system, and use a tissue pulverizer to stir rapidly for 10 minutes to obtain a uniform and stable film-forming suspension _; The suspension was repeatedly washed with water, and finally the suspension was dispersed into a uniform slurry with deionized water to obtain a suspension of para-aramid nanofibers with a mass concentration of 0.5%, wherein the diameter of the para-aramid nanofibers was about 20nm. The average length is around 100 μm.

Example 1

The above-mentioned para-aramid nanofiber suspension is sprayed on the inclined net by high pressure using the inclined net forming technology of the inclined net former, and the mesh number of the forming net is 100 mesh. Suction dehydration combined with top wire former dehydration combined dehydration method for two-way dehydration; in the process of vacuum suction dehydration, as the dryness of wet paper embryo increases from 3% to 5%, the vacuum of vacuum suction The pressure increases from -0.06MPa to -0.1MPa to get wet paper.

After the formed wet paper is peeled off from the forming net by vacuum adsorption transfer method, vacuum press dehydration is carried out. During the vacuum press dehydration process, as the dryness of the wet paper increases to 10%, the pressure of vacuum press dehydration increases from 0.15MPa to 10%. , 0.20MPa, 0.25MPa, and 0.30MPa increase (4-stage buffer vacuum press dehydration), the vacuum degree of vacuum press dehydration is -20KPa, and the high-pressure water pressure for felt cleaning during vacuum press dehydration is 1.5MPa.

The dehydrated paper is dried with 8-level steam. With the increase of the dryness of the dehydrated paper, the drying temperature is increased from 80°C to 120°C, and then the tension of the tension device is 7.5kN/m. Under the action of stretching, the paper is heat-set, the heat-setting temperature is 130°C for 6 minutes, and finally it is calendered to obtain para-aramid paper.

The para-aramid paper prepared in Example 1 of the present invention has a thickness of 50 μm. Its performance was tested according to the above method, and the test results showed that the tensile strength was 60MPa, the elongation was 1.7%, the tearing degree was 800mN, and the electrical insulation performance was 95kV/mm.

Example 2:

The above-mentioned para-aramid nanofiber suspension is sprayed on the inclined net by high pressure using the inclined net forming technology of the inclined net former, and the mesh number of the forming net is 100 mesh. Suction dehydration combined with top wire former dehydration combined dehydration method for two-way dehydration; in the vacuum suction dehydration process, as the dryness of the wet paper embryo increases from 3% to 5%, the vacuum of vacuum suction dehydration The degree increases from -0.01MPa to -0.05MPa to get wet paper.

The formed wet paper is peeled off from the forming net by vacuum adsorption transfer method and then dehydrated by vacuum press. During the process of vacuum press dehydration, as the dryness of the wet paper increases to 15%, the pressure of vacuum press dehydration is sequentially increased from 0.15 to 15%. MPa, 0.20MPa, 0.25MPa, and 0.30MPa increase (4-stage buffer vacuum press dehydration), the vacuum degree of vacuum press dehydration is -40KPa, and the pressure of high-pressure water for felt cleaning during vacuum press dehydration is 2.5MPa.

Dry the dehydrated paper with 8-level steam. With the increase of the dryness of the dehydrated paper, increase the drying temperature from 80°C to 120°C, and then stretch it under the tension device with a tension of 7.5kN/m The paper is heat-set at a temperature of 130°C for 6 minutes, and finally calendered to obtain para-aramid paper.

The para-aramid paper prepared in Example 2 of the present invention has a thickness of 80 μm. Its performance was tested according to the above method, and the test results showed that the tensile strength was 120MPa, the elongation was 1.7%, the tearing degree was 1400mN, and the electrical insulation performance was 85kV/mm.

Example 3:

The above-mentioned para-aramid nanofiber suspension is sprayed on the inclined net by high pressure using the inclined net forming technology of the inclined net former, and the mesh number of the forming net is 100 mesh. Suction dehydration combined with top wire forming dehydration for two-way dehydration; in the process of vacuum suction dehydration, as the dryness of the wet paper embryo increases from 3% to 5%, the vacuum degree of vacuum suction dehydration Increase from -0.01MPa to -0.05MPa to get wet paper.

After the formed wet paper is peeled off from the forming net by vacuum adsorption transfer method, vacuum press dehydration is carried out. During the vacuum press dehydration process, as the dryness of the wet paper increases to 12%, the pressure of vacuum press dehydration increases from 0.20MPa to , 0.25MPa, 0.30MPa, and 0.35MPa increase (4-stage buffer vacuum press dehydration), the vacuum degree of vacuum press dehydration is -30KPa, and the high-pressure water pressure for felt cleaning during vacuum press dehydration is 2MPa.

The dehydrated paper is dried with 8-level steam. With the increase of the dryness of the dehydrated paper, the drying temperature is increased from 100°C to 120°C, and then under the tension of the tension device with a tension of 7kN/m The paper was heat-set at 140°C for 9 minutes, and finally calendered to obtain para-aramid paper.

The para-aramid paper prepared in Example 3 of the present invention has a thickness of 120 μm. Its performance was tested according to the above method, and the test results showed that the tensile strength was 110MPa, the elongation was 1.5%, the tearing degree was 2000mN, and the electrical insulation performance was 70kV/mm.

Example 4:

The above-mentioned para-aramid nanofiber suspension is sprayed on the inclined net by high pressure using the inclined net forming technology of the inclined net former, and the mesh number of the forming net is 100 mesh. Suction dehydration combined with top wire former dehydration combined dehydration method for two-way dehydration; in the process of vacuum suction dehydration, as the dryness of wet paper embryo increases from 3% to 5%, the vacuum of vacuum suction The degree increases from -0.01MPa to -0.05MPa to get wet paper.

After the formed wet paper is peeled off from the forming net by vacuum adsorption transfer method, vacuum press dehydration is carried out. During the vacuum press dehydration process, as the dryness of the wet paper increases to 13%, the pressure of vacuum press dehydration increases from 0.15MPa to , 0.20MPa, 0.25MPa, and 0.30MPa increase (4-stage buffer vacuum press dehydration), the vacuum degree of vacuum press dehydration is -35KPa, and the high-pressure water pressure for felt cleaning during vacuum press dehydration is 2.2MPa.

The dehydrated paper is dried with 8 steams. With the increase of paper dryness after dehydration, the drying temperature is increased from 100°C to 120°C, and then the paper is heated under the tension of a tensioning device with a tension of 7kN/m. Shaping, heat setting at 140°C for 12 minutes, and finally calendering to obtain para-aramid paper.

The para-aramid paper prepared in Example 4 of the present invention has a thickness of 200 μm. Its performance was tested according to the above method, and the test results showed that the tensile strength was 150MPa, the elongation was 1.5%; the tearing degree was 2000mN, and the electrical insulation performance was 60kV/mm.

Comparative example 1

Commercially available Yantai Minshida YT836 para-aramid paper was used.

The properties of the para-aramid paper of Comparative Example 1 of the present invention were tested according to the above method. The test results showed that the tensile strength was 45 MPa; the elongation was 2.0%; the tearing degree was 1200 mN; and the electrical insulation performance was 16 kV/mm.

Comparative example 2

The para-aramid paper was prepared according to the method of Example 1. The difference from Example 1 is that the online forming method is to directly spray the para-aramid nanofiber material liquid on the inclined net for forming at high pressure, and only carry out upper net forming. dehydration.

The para-aramid paper prepared in comparative example 2 of the present invention has a thickness of 50 μm; the performance of the para-aramid paper prepared in comparative example 2 of the present invention is tested according to the above method, and the test result is that the tensile strength is 45 MPa; the elongation It is 1.5%; the tearing degree is 750mN; the electrical insulation performance is 60kV/mm.

Comparative example 3

The para-aramid paper was prepared according to the method of Example 1. The difference from Example 1 is that the online forming method is to directly spray the para-aramid nanofiber material liquid on the inclined net at high pressure for forming, and only carry out the lower vacuum suction dehydration.

The para-aramid paper prepared in Comparative Example 3 of the present invention has a thickness of 50 μm; the performance of the para-aramid paper prepared in Comparative Example 3 of the present invention is tested according to the above method, and the test result is that the tensile strength is 40 MPa; the elongation It is 1.4%; the tearing degree is 600mN; the electrical insulation performance is 40kV/mm.

As can be seen from the above examples, the present invention provides a method for preparing para-aramid paper, comprising: forming the para-aramid nanofiber material liquid on the Internet to obtain wet paper; performing multi-stage buffer pressing on the wet paper dehydration to obtain dehydrated wet paper; the dehydrated wet paper is sequentially subjected to a multi-stage low-temperature drying process and a tension-assisted drying process for drying and forming to obtain para-aramid paper; the method of online forming is: After the para-aramid nanofiber material liquid is sized, it is filtered, and a wet paper embryo is formed on the surface of the forming wire; the lower surface of the wet paper embryo is first vacuumed and dehydrated, and then the wet paper embryo is formed with an upper top wire former. Two-way dehydration is carried out by combining dehydration on the upper surface of the paper to obtain wet paper. The present invention adopts a special net forming process, a multi-stage buffer pressing process, a multi-stage low-temperature drying process and a tension-assisted drying process to prepare the aramid paper with good uniformity, excellent mechanical properties and insulating properties.

What has been described above is only a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements and modifications can also be made without departing from the principles of the present invention. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of p-aramid paper, including：

P-aramid fiber nanofiber feed liquid is subjected to upper net forming, obtains wet paper；

The processing of multi-buffer press dewatering is carried out to the wet paper, obtains dewatered wet paper；

The dewatered wet paper is dried and is formed with press polish, p-aramid paper is obtained；

The drying is that multistage low temperature drying and tension assist drying；

The molding method of the online is：

By drainage after the p-aramid fiber nanofiber feed liquid starching, l Water Paper embryo is formed in molding net surface；

The lower surface of the l Water Paper embryo be sucked by vacuum and is then carried out using upper surface of the upper top net former to l Water Paper embryo It is dehydrated the mode combined and carries out two-way dehydration, obtain wet paper.

2. the method according to claim 1, wherein p-aramid fiber is received in the p-aramid fiber nanofiber feed liquid The diameter of rice fiber is 10~100nm.

3. the method according to claim 1, wherein p-aramid fiber is received in the p-aramid fiber nanofiber feed liquid The length of rice fiber is 100nm~1000 μm.

4. the method according to claim 1, wherein the mass concentration of the p-aramid fiber nanofiber feed liquid is 0.5~2.5%.

5. the method according to claim 1, wherein the vacuum degree of the vacuum suction be -0.01~- 0.1MPa。

6. the method according to claim 1, wherein the mass dryness fraction of the wet paper is 8~10%.

7. the method according to claim 1, wherein the Pressing Number of the multi-buffer press dewatering is 2~5 Grade；The pressure of the multi-buffer press dewatering gradually increases within the scope of 0.05~0.35MPa.

8. the method according to claim 1, wherein it is described multistage low temperature drying drying series be 6~10 grades, The temperature of the multistage low temperature drying gradually increases within the scope of 60~120 DEG C.

9. the method according to claim 1, wherein the tension of tension auxiliary drying is 4~10kN/m, institute Stating the dry temperature of tension auxiliary is 120~160 DEG C.

10. a kind of p-aramid paper that method described in claim 1 is prepared.