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CN-121976315-A - High-strength polyhexamethylene adipamide fiber and preparation method thereof

CN121976315ACN 121976315 ACN121976315 ACN 121976315ACN-121976315-A

Abstract

The invention belongs to the technical field of high polymer materials, and discloses a high-strength polyhexamethylene adipamide fiber and a preparation method thereof. The invention leads the nucleating agent to be uniformly distributed in the matrix in submicron level through the masterbatch pre-dispersing process. In the melt spinning cooling stage, uniformly distributed particles serve as efficient heterogeneous nucleating agents, the polyhexamethylene adipamide molecular chains are induced to be arranged in a rapid and orderly mode, the crystallinity and the crystal perfection of the fiber are obviously improved, and the generation of alpha crystal forms is promoted. The optimization of the microstructure counteracts the toughness reduction side effect usually brought by the rigid particles, thereby realizing the synchronous improvement of the strength and the modulus.

Inventors

  • YU HAO
  • ZHAO JIE
  • YU BIN
  • HUANG TAO
  • SU CHENYU
  • LU XU
  • AI LI

Assignees

  • 东华大学

Dates

Publication Date
20260505
Application Date
20260409

Claims (9)

  1. 1. A method for preparing high-strength polyhexamethylene adipamide fiber, which is characterized by comprising the following steps: (1) Stirring and mixing polyamide resin, nucleating agent and antioxidant in a high-speed mixer to obtain premix; (2) Fully drying the premix obtained in the step (1), adding the premix into a double-screw extruder for melt extrusion, and cooling and granulating to obtain the polyhexamethylene adipamide fiber reinforcing agent; (3) And (3) fully drying the polyhexamethylene adipamide fiber reinforcing agent obtained in the step (2) and the polyhexamethylene adipamide slices, mixing, and carrying out melt spinning processing to obtain the high-strength polyhexamethylene adipamide fiber.
  2. 2. The preparation method of the high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (1), the premix comprises, by mass, 2% -10% of a nucleating agent, 0.02% -2% of an antioxidant and the balance of polyamide resin.
  3. 3. The method for producing a high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (1), the polyamide resin is one selected from the group consisting of polycaprolactam, polyundecanamide and polydodecamide.
  4. 4. The method for producing a high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (1), the viscosity average molecular weight of the polyamide resin is 20000 to 28000g/mol.
  5. 5. The method for producing high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (1), the nucleating agent is at least one selected from the group consisting of poly-p-phenylene benzobisoxazole microfiber, functionalized multi-walled carbon nanotubes, silicon carbide whiskers and nano-titania.
  6. 6. The method for producing a high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (1), the antioxidant is at least one selected from the group consisting of organic antioxidants and inorganic antioxidants.
  7. 7. The method for preparing high strength polyhexamethylene adipamide fiber according to claim 6, wherein said organic antioxidant is selected from one of phenols, hindered phenols, phosphites, amines, hindered amine antioxidants.
  8. 8. The method for producing a high-strength polyhexamethylene adipamide fiber according to claim 1, wherein in the step (3), the mass ratio of the polyhexamethylene adipamide fiber reinforcing agent to the polyhexamethylene adipamide chips is 1-5:90-97.
  9. 9. A high strength polyhexamethylene adipamide fiber obtained by the process of any one of claims 1-8.

Description

High-strength polyhexamethylene adipamide fiber and preparation method thereof Technical Field The invention belongs to the technical field of high polymer materials, and particularly relates to a high-strength polyhexamethylene adipamide fiber and a preparation method thereof. Background Polyhexamethylene adipamide, commonly known as nylon 66, is an important semi-crystalline engineering plastic and is widely used in the fields of fibers, composite materials and the like due to its excellent mechanical properties, heat resistance, wear resistance and chemical stability. In particular, in the aspect of high-performance fibers, the requirements on tire cord, airbag fabrics, industrial yarns, special clothing fabrics and the like are remarkable. However, in certain applications where strength, modulus, dimensional stability and durability are more desirable, there is room for improvement in the properties of pure polyhexamethylene adipamide fibers. The existing technology for reinforcing the polyhexamethylene adipamide fiber generally improves spinnability by adding inorganic filler, optimizing the spinning temperature, cooling wind speed and other technological parameters. However, in the research, it is found that the inorganic filler is directly added to cause uneven dispersion in the matrix to form an aggregate, so that the spinneret plate is easily blocked, and the spinning breakage rate is greatly increased. In addition, although improving the crystallinity can improve the strength, too fast a crystallization rate can lead to premature solidification of the melt trickle on the spinning line, reduce the draft multiple, and adversely affect the improvement of the orientation degree. For example, patent CN118126522a discloses a method for improving the fiber strength of polyhexamethylene adipamide by copolymerizing the modified polyhexamethylene adipamide. The preparation method comprises the steps of carrying out co-salification reaction on adipic acid, hexamethylenediamine, aminosiloxane and deionized water to obtain an amide salt solution, adding a catalyst, a molecular weight regulator and methyl silicone oil, stirring and mixing uniformly, and carrying out prepolymerization reaction under the protection of nitrogen. After the prepolymerization reaction is finished, the vacuum degree is reduced, and the polycondensation reaction is carried out under the low vacuum condition, so that the copolymerized modified polyhexamethylene adipamide with low gel content is prepared. After spinning, the fiber strength is good, however, a small amount of gel still affects the spinning stability. In the prior art, the balance between uniform dispersion of the filler, controllable crystallization rate and spinning stability is difficult to be considered. Therefore, there is a need for a high strength polyhexamethylene adipamide fiber and method of making the same that can increase the crystallization rate of the matrix to facilitate rapid curing, and also ensure uniform dispersion of the filler to reduce processing difficulties. Disclosure of Invention In view of the above, the present invention provides a high-strength polyhexamethylene adipamide fiber and a preparation method thereof, which uses a melt blending process to increase the strength of the polyhexamethylene adipamide fiber and improve the spinnability thereof, and has potential for industrial production. In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for preparing high strength polyhexamethylene adipamide fiber, comprising the steps of: (1) Stirring and mixing polyamide resin, nucleating agent and antioxidant in a high-speed mixer to obtain premix; (2) Fully drying the premix obtained in the step (1), adding the premix into a double-screw extruder for melt extrusion, and cooling and granulating to obtain the polyhexamethylene adipamide fiber reinforcing agent; (3) And (3) fully drying the polyhexamethylene adipamide fiber reinforcing agent obtained in the step (2) and the polyhexamethylene adipamide slices, mixing, and carrying out melt spinning processing to obtain the high-strength polyhexamethylene adipamide fiber. Preferably, in the step (1), the premix comprises, by mass, 2% -10% of a nucleating agent, 0.02% -2% of an antioxidant and the balance of polyamide resin. The polyamide resin in the fiber reinforcing agent has good melt fluidity and compatibility, so that the filler is wrapped and dispersed in advance, and the dispersibility in spinning is improved. The nucleating agent serves as a heterogeneous nucleation point in a blending system, so that the crystallization rate and the crystallinity of the polyhexamethylene adipamide are remarkably improved, the processing window is widened, and the antioxidant prevents the thermal oxidative degradation of the blend in the high-temperature melt shearing process. The three components cooperate to ensure that the fiber can obtain excellent mecha