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CN-122013349-A - Method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning

CN122013349ACN 122013349 ACN122013349 ACN 122013349ACN-122013349-A

Abstract

The invention discloses a method for preparing PA6/56 bio-based copolyamide fibers by melt direct spinning, which comprises the steps of mixing raw materials comprising caprolactam solution, PA56 salt solution and a molecular weight regulator, preheating, performing prepolymerization reaction and polycondensation reaction to obtain PA6/56 copolymer melt, performing devolatilization to obtain PA6/56 devolatilization melt, and performing melt spinning on the PA6/56 devolatilization melt to obtain PA6/56 bio-based copolyamide fibers. In the invention, 1, 5-pentanediamine from biological base is adopted as the raw material of PA56, and after being configured, the raw material is firstly preheated and pre-condensed, and then the number average molecular weight of nylon 6 prepolymer is further increased by polycondensation, and the obtained copolymer melt is in a molten state. The copolymer is removed from the oligomer through a devolatilization reactor, so that the liquid phase extraction of PA6/56 is realized, the extractable content of the obtained copolymer melt is less than or equal to 2wt%, the process flow is simplified, and the production period, the equipment investment cost and the production energy consumption are greatly reduced.

Inventors

  • YANG XIANWEN
  • Ran qidi
  • WANG WENHUI
  • DONG FAN
  • Wang Bangsen
  • QIN HAO
  • DAI RENQIANG
  • WANG SONGLIN

Assignees

  • 浙江恒逸石化研究院有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. A method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning, comprising the steps of: s1, mixing raw materials containing caprolactam and water to obtain a caprolactam solution, and mixing raw materials containing 1, 5-pentanediamine, adipic acid and water to obtain a PA56 salt solution; S2, mixing raw materials comprising caprolactam solution, PA56 salt solution and a molecular weight regulator, preheating, carrying out prepolymerization reaction and polycondensation reaction to obtain PA6/56 copolymer melt, and carrying out devolatilization to obtain PA6/56 devolatilized melt; S3, conveying the PA6/56 devolatilized melt to a spinning assembly through a booster pump, a melt filter, a metering pump and a spinning box, and carrying out melt spinning to obtain fibers, wherein the fibers are cooled, oiled, drawn and wound to obtain the PA6/56 bio-based copolyamide fibers.
  2. 2. The method for preparing PA6/56 bio-based copolyamide fiber according to claim 1, wherein the relative viscosity of the PA6/56 devolatilized melt is 2.5-3.5, the number average molecular weight is 30000-100000, and the extractables content is less than or equal to 2%.
  3. 3. The method for preparing PA6/56 biobased copolyamide fiber by melt direct spinning according to claim 1, wherein the raw material in S2 further comprises an auxiliary agent, the auxiliary agent comprises one or more of an antioxidant and a matting agent, and the addition mass of the auxiliary agent is 0.1-4.0wt% of the total mass of caprolactam and glutarimide adipate.
  4. 4. The method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning according to claim 1, wherein the addition mass of water in caprolactam solution is 1-5wt% of caprolactam; the molar ratio of the 1, 5-pentanediamine to the adipic acid is (1-1.2) 1, wherein the mass concentration of polyamide 56 salt in the PA56 salt solution is 20-80%; the mixing temperature is 75-120 ℃ and the mixing time is 1-10 h.
  5. 5. The method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning according to claim 1, wherein the molar ratio of polyamide 56 salt in the PA56 salt solution to caprolactam in the caprolactam solution in S2 is (50:50) - (90:10); The molecular weight regulator comprises acetic acid, HOOC (CH 2 ) z COOH, terephthalic acid, phthalic acid, aromatic amine, hindered amine and diamine, wherein the diamine comprises one or more of H 2 N(CH 2 ) z NH 2 , p-xylylenediamine, o-phenylenediamine, m-phenylenediamine and decamethylenediamine, z is 2-10, and the addition amount is 0.1-0.8% of the total mass of caprolactam and adipic acid glutarimide.
  6. 6. The method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning according to claim 1, wherein the preheating temperature in S2 is 140-200 ℃ and the preheating time is 1-5 h; The preheater adopts equipment comprising one or more of a shell-and-tube type, a stirred tank type and a bellows type for preheating, wherein the temperature of the prepolymerization reaction is 210-270 ℃, the prepolymerization is carried out for 5-15 hours under the condition of 0.5-2.5 mpa in the tank, the relative viscosity of a product obtained by the prepolymerization reaction is 1.3-1.8, and the content of an extractable matter is 9.0-15.5 wt%.
  7. 7. The method for preparing PA6/56 bio-based copolyamide fiber according to claim 1, wherein the polycondensation reaction temperature is 230-290 ℃, the pressure in a kettle is controlled to be-0.9-0.3 bar, the polycondensation time is controlled to be 6-20 h, the relative viscosity of the obtained PA6/56 copolyamide fiber is 1.8-2.2, and the extractable matter content is 5.0-10.5wt%.
  8. 8. The method for preparing PA6/56 bio-based copolyamide fiber according to claim 1, wherein the devolatilization temperature in S2 is 250-290 ℃, the absolute pressure is 0.05-20kPa, and the devolatilization time is 0.5-3.0h; The reactor for devolatilization comprises one or more of a flash evaporator, a film devolatilizer, a falling film evaporator, a stirring evaporation kettle, a falling strip type, a screw extrusion type common rotary disc devolatilizer paddle devolatilizer and a rotary packed bed, wherein the devolatilization grade is one of a single stage, a secondary stage and a tertiary stage.
  9. 9. The method for producing PA6/56 bio-based copolyamide fiber according to claim 1, characterized in that PA6/56 devolatilization melt transfer temperature in S3 is 250-270 ℃, melt filter cartridge 1-10 μm.
  10. 10. The method of preparing PA6/56 bio-based copolyamide fiber according to claim 1 wherein the spinneret type of the spin pack comprises one of round, trilobal, flat, dumbbell, triangular, diamond; The melt spinning speed is controlled at 3000-5500m/min, the spinning temperature is controlled at 250-290 ℃, lateral blowing or circular blowing is adopted for cooling, the lateral blowing air temperature is 16-19 ℃, the lateral blowing speed is 0.3-0.7m/s, the lateral blowing humidity is 55-85%, and the height of a windless area is 30-50mm.

Description

Method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning Technical Field The invention relates to the technical field of composite fiber preparation, in particular to a method for preparing PA6/56 bio-based copolyamide fiber by melt direct spinning. Background Polyamide 6 (PA 6) fiber has been widely used in textile fabrics and other fields because of its light weight, high strength, moisture absorption, easy dyeing and other advantages. The raw materials of the traditional polyamide production process are petroleum, and the problems of high energy consumption, high carbon emission and the like exist through the polycondensation of binary acid/diamine monomers and the ring-opening polymerization of amino acid polycondensation/lactam monomers. The development, application and substitution of traditional petroleum-based materials for bio-based environmental-friendly raw materials are the hot spot of current research. The bio-based polyamide is prepared by taking renewable resources as raw materials, biologically fermenting raw materials such as glucose or cellulose or cracking vegetable oil (comprising castor oil, oleic acid and linoleic acid) to prepare a bio-based polyamide monomer, and further polycondensating the bio-based polyamide monomer to obtain the bio-based polyamide. PA56 is a novel bio-based polyamide material with excellent hygroscopicity, rebound resilience and dyeability, and is widely used in clothing textile industry and other industries. Compared with the traditional petroleum-based nylon, the PA56 has lower thermal deformation temperature, crystallinity and mechanical property, and the production cost is easy to fluctuate due to the supply and demand of biological raw materials, and the production cost is high, so that the application and the industrialized popularization of the PA56 are limited. The performance defect of the bio-based copolyamide formed by copolymerizing the PA56 and other high-crystallinity and high-strength polyamide materials (such as PA 6) can be overcome by adjusting the proportion and the structure. For PA6/5X copolymer fiber, especially in textile field, low molecular polymer (short for oligomer) is produced in the copolymerization process of PA6/56, mainly because the polymerization reaction of PA6 is equilibrium reaction, the reaction product contains about 10% of monomer and oligomer, which can not be spun and formed, and a large number of small molecules enter the spinning section, which not only can seriously affect the spinning process, but also greatly waste raw materials. At present, a melt spinning process route of slice spinning is generally adopted to produce PA6/56 copolyamide fibers, namely, PA6/56 copolymer is obtained through polymerization, then slices are obtained through extrusion and granulation, extraction and drying, and the slices are spun and molded after being extruded and melted by a screw and metered by a metering pump. For example, CN115449069a discloses "a copolyamide resin, copolyamide fiber and its preparation", a polyamide 56 salt solution and a caprolactam aqueous solution are polymerized, and a product obtained by the polymerization is mixed with water, extracted and filtered to obtain the copolyamide resin. And the copolyamide fiber is finally obtained by spinning after the resin is melted, and has excellent softness, mechanical property, hygroscopicity and dyeing property. CN108250433A discloses a PA6-56 copolymer material and a preparation method thereof, caprolactam is used as a main material, and PA56 monomer adipic acid pentanediamine salt is copolymerized to prepare the PA6-56 copolymer material, and the PA6-56 copolymer material is subjected to granulating, hot water extraction and drying to obtain slices, so that the PA6 copolymer material has the advantages of high strength, wear resistance, acid and alkali resistance of PA6, and has better hygroscopicity and dyeability. CN118007276a discloses "a bio-based polyamide carpet yarn and a preparation method thereof", which is prepared by reacting bio-based polyamide 56 salt with caprolactam to obtain polyamide 6/56 copolymer particles. After washing and drying, the PA6/56 copolyamide carpet yarn obtained by screw extrusion melting and spinning has good performance indexes. The process needs to be firstly subjected to granulation, extraction and drying to obtain slices, and then subjected to melt spinning to obtain the PA6/56 copolyamide fiber, so that the equipment investment cost is high, the process flow is complex, the raw material turnover period is long, the water consumption and the energy consumption are high, and the popularization and the industrialization are not facilitated. Therefore, development of a novel process for realizing direct spinning by copolymerizing bio-based PA56 and traditional polyamide 6 is a problem to be solved. Disclosure of Invention Aiming at the problem that the melt cannot be directly spun due to high extractable matter