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CN-121992522-A - Low-energy-consumption dry meta-aramid fiber and production method thereof

CN121992522ACN 121992522 ACN121992522 ACN 121992522ACN-121992522-A

Abstract

The invention provides a low-energy-consumption meta-aramid fiber, which is prepared by polymerizing meta-phenylenediamine and isophthaloyl dichloride in DMAC at a temperature of not higher than 10 ℃ to prepare spinning solution, and performing dry spinning and gradient curing to prepare the low-energy-consumption meta-aramid fiber, wherein gradient cooling and reverse solvent evaporation are performed in a spinning channel, the strength of the meta-aramid fiber is not lower than 4.5cN/dtex, the production energy consumption is not higher than 6.0KWh/kg fiber, and the heat recovery efficiency is not higher than 65%. The preparation method comprises the steps of polymerization and spinning solution preparation, vacuum defoamation and filtration, dry spinning, namely pressing the spinning solution into a spinneret plate to obtain nascent fibers, enabling the nascent fibers to enter a spinning channel, enabling hot air in the channel to be controlled by three-zone gradient temperature, solvent recovery and heat energy circulation, namely, introducing tail gas discharged from the spinning channel into a condensing system after heat exchange, condensing and recovering DMAC, recycling condensation released waste heat, enabling heat recovery efficiency to be more than or equal to 65%, and drafting and heat setting, namely, obtaining meta-position aramid fibers with strength of more than or equal to 4.5cN/dtex after drafting and setting.

Inventors

  • FAN ZHIPING
  • ZHU BIN
  • GUO JUNYAO

Assignees

  • 上海芳纶谷新材料有限公司
  • 江苏奥维芳纶纤维有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (10)

  1. 1. A low-energy-consumption meta-aramid fiber is characterized in that m-phenylenediamine and isophthaloyl dichloride are polymerized in DMAC at a temperature of not higher than 10 ℃ to prepare spinning solution, the spinning solution is subjected to dry spinning and gradient solidification to prepare the low-energy-consumption meta-aramid fiber, gradient cooling and reverse solvent evaporation are carried out in a spinning channel, the strength of the meta-aramid fiber is not lower than 4.5cN/dtex, the energy consumption in the production of the meta-aramid fiber is not higher than 6.0KWh/kg fiber, the recovery rate of the DMAC is not lower than 98%, and the heat recovery rate is not lower than 65%.
  2. 2. An industrial process for preparing the low energy meta-aramid fiber of claim 1, comprising the steps of: S1, preparing a polymerization and spinning solution, namely performing low-temperature polymerization on m-phenylenediamine and m-phthaloyl chloride in DMAC at a temperature of not higher than 10 ℃ to prepare a poly m-phthaloyl m-Phenylenediamine (PMIA)/DMAC spinning solution; S2, vacuum defoaming and filtering, namely filtering the spinning solution after defoaming under a vacuum condition; S3, dry spinning, namely pressing the filtered spinning solution into a spinneret plate through a metering pump to obtain nascent fibers, wherein the nascent fibers enter a spinning channel, and hot air in the spinning channel is controlled by adopting three-zone gradient temperature; S4, solvent recovery and heat energy circulation, namely, introducing tail gas discharged from a spinning channel into a condensing system after heat exchange, condensing and recovering DMAC, wherein the recovery rate is more than or equal to 98%, recycling condensing and releasing waste heat, and the heat recovery efficiency is more than or equal to 65%; s5, drawing and heat setting, namely drawing and setting the nascent fiber to obtain the meta-aramid fiber with the strength of more than or equal to 4.5 cN/dtex.
  3. 3. The industrial production method of low-energy meta-aramid fiber as claimed in claim 2, wherein in the step of S1, the solid content of the spinning solution is 20-25wt%, and the intrinsic viscosity of the spinning solution is not less than 1.8dL/g.
  4. 4. The industrial production method of the meta-aramid fiber with low energy consumption according to claim 2, wherein in the step S2, the defoaming temperature is 40-50 ℃, the defoaming vacuum degree is less than or equal to-0.095 MPa, the defoaming time is 30-60 min, and the filtering precision is less than or equal to 5 μm.
  5. 5. The industrial production method of the low-energy meta-aramid fiber according to claim 2, wherein in the step S3, the hole diameter of the spinneret plate is 0.06-0.08 mm, the hole number is 1000-3000, and the ejection temperature of the fiber from the spinneret plate is 80-100 ℃.
  6. 6. The industrial production method of the meta-aramid fiber with low energy consumption according to claim 2, wherein in the step S3, the gradient temperature of the three regions is that the temperature of hot air in the first region (inlet section) is controlled to be 120-140 ℃, the wind speed is set to be 0.8-1.2 m/S, the temperature of hot air in the second region (middle section) is controlled to be 100-120 ℃, and the wind speed is set to be 1.5-2.0 m/S; The temperature of hot air in the third area (outlet section) is controlled to be 80-90 ℃ and the wind speed is set to be 0.5-0.8 m/s.
  7. 7. The industrial production method of the low-energy meta-aramid fiber as claimed in claim 2, wherein the spinning channel is less than or equal to 5.5m in height, a reverse three-zone hot air system is adopted in the spinning channel, auxiliary air inlets and auxiliary heating systems are arranged in the first zone and the second zone, fresh hot air enters from the air inlet at the bottom side wall of the third zone, flows upwards and reversely through the second zone and the first zone and is discharged from the air outlet at the upper side wall of the first zone, and the highest temperature of the spinning channel is not higher than 140 ℃.
  8. 8. The industrial production method of the meta-aramid fiber with low energy consumption according to claim 7 is characterized in that the air inlet is an annular porous plate with an opening ratio of 25% -35%, and the air outlet is an annular air suction groove connected with a negative pressure fan.
  9. 9. The method for industrially producing a meta-aramid fiber having low energy consumption according to claim 2, wherein the condensing temperature is not higher than-10 ℃ in the step of "S4".
  10. 10. The industrial production method of the low-energy meta-aramid fiber as claimed in claim 2, wherein in the step of S4, the draft multiple is 1.5-2.5, the shaping temperature is 180-220 ℃, and the shaping time is 30-60S.

Description

Low-energy-consumption dry meta-aramid fiber and production method thereof Technical Field The invention belongs to the technical field of high-performance fiber manufacturing, relates to meta-aramid fiber and a production method thereof, and in particular relates to a production method for realizing low-energy-consumption green meta-aramid fiber by adopting N, N-dimethylacetamide as a solvent through dry spinning and the produced meta-aramid fiber. Background Meta-aramid fiber is a key material in the fields of aerospace, special protection and the like because of excellent high temperature resistance, high strength, flame retardance and electrical insulation. At present, the industrial production method of meta-aramid fiber mainly comprises wet spinning, dry spinning, N-Dimethylacetamide (DMAC) wet spinning and the like. However, the prior art has the problems of high energy consumption or large environmental pollution and the like (1) that wet spinning requires a large amount of coagulating bath and high energy consumption water washing, and the wastewater treatment burden is heavy, (2) that the traditional dry spinning does not need water washing, but the temperature of hot air is usually not lower than 280 ℃ and the energy consumption for solvent recovery is extremely high, and (3) that DMAC wet spinning relies on water bath coagulation and the energy consumption for subsequent drying is high. (4) The energy consumption of the method is generally 8.5-12 kWh/kg of fiber, and the method has the problems of incomplete solvent volatilization, insufficient fiber densification and the like. Therefore, there is an urgent need to develop a meta-aramid fiber production method which has low energy consumption, high fiber strength, and controllable cost and is suitable for large-scale industrial production, and meta-aramid fiber produced according to the production method. Disclosure of Invention In order to overcome the defects in the prior art, the invention aims to (1) provide meta-aramid fiber with low energy consumption and high strength. (2) Provides a meta-aramid fiber production method which has low energy consumption and controllable cost and is suitable for large-scale industrial production. In order to achieve the aim, the invention provides a low-energy-consumption meta-aramid fiber, which is prepared by polymerizing m-phenylenediamine and isophthaloyl dichloride in DMAC at a temperature of not higher than 10 ℃ to prepare spinning solution, and performing dry spinning and gradient curing to prepare the low-energy-consumption meta-aramid fiber, wherein gradient cooling and reverse solvent evaporation are performed in a spinning channel, the strength of the meta-aramid fiber is not lower than 4.5cN/dtex, the energy consumption in the production of the meta-aramid fiber is not higher than 6.0KWh/kg fiber, and the recovery rate of the DMAC solvent is not lower than 98%. In order to achieve the above object, the present invention provides an industrial production method for preparing the low-energy meta-aramid fiber, comprising the steps of: S1, polymerizing m-phenylenediamine and isophthaloyl dichloride in DMAC at a low temperature of not higher than 10 ℃ to prepare a poly m-phenylene isophthalamide (PMIA)/DMAC spinning solution; S2, vacuum defoaming and filtering, namely filtering the spinning solution after defoaming under a vacuum condition; S3, dry spinning, namely pressing the filtered spinning solution into a spinneret plate through a metering pump to obtain nascent fibers, wherein the nascent fibers enter a spinning channel, and hot air in the spinning channel is controlled by adopting three-zone gradient temperature; S4, solvent recovery and heat energy circulation, namely, introducing tail gas discharged from a spinning channel into a condensing system after heat exchange, condensing and recovering DMAC, wherein the recovery rate is more than or equal to 98%, recycling condensing and releasing waste heat, and the heat recovery efficiency is more than or equal to 65%; s5, drawing and heat setting, namely drawing and setting the nascent fiber to obtain the meta-aramid fiber with the strength of more than or equal to 4.5 cN/dtex. In the low-energy-consumption meta-aramid fiber industrial production method provided by the invention, in the step S1, the solid content of the spinning solution is 20-25wt%, and the intrinsic viscosity of the spinning solution is more than or equal to 1.8dL/g. In the industrial production method of the meta-aramid fiber with low energy consumption, in the step S2, the defoaming temperature is 40-50 ℃, the defoaming vacuum degree is less than or equal to-0.095 MPa, the defoaming time is 30-60 min, and the filtering precision is less than or equal to 5 mu m. In the industrial production method of the low-energy meta-aramid fiber, in the step S3, the aperture of a spinneret plate is 0.06-0.08 mm, the aperture number is 1000-3000, and the ejection temperature of the fiber fro