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CN-121161453-B - Method for producing crimped composite fiber and crimped composite fiber obtained thereby

CN121161453BCN 121161453 BCN121161453 BCN 121161453BCN-121161453-B

Abstract

The invention relates to a method for preparing crimped composite fibers and crimped composite fibers obtained by the method, which comprises the steps of a) providing composite fibers comprising a first component and a second component which are compounded in parallel, b) performing supercritical fluid infiltration on the composite fibers in the step a), c) foaming and crimping the composite fibers subjected to supercritical fluid infiltration in the step b), and d) shaping the foamed and crimped composite fibers in the step c). The crimped composite fibers have improved fiber crimp shrinkage and thermal retention.

Inventors

  • WANG NI
  • CHEN YUMEI

Assignees

  • 昊太(江苏)新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20250827
Priority Date
20241113

Claims (6)

  1. 1. A method of making crimped composite fibers, comprising the steps of: a) Providing a composite fiber comprising a first component and a second component in side-by-side combination, the first component of the composite fiber having a higher softening point than the second component; b) The method comprises the steps of a), carrying out supercritical fluid infiltration on the composite fiber in the step a), putting the composite fiber in a high-pressure bin containing the supercritical fluid in the step b), and starting from normal pressure, reaching a set supercritical fluid infiltration pressure P1 in an initial time T0, and simultaneously raising the temperature to enable the composite fiber to reach the set supercritical fluid infiltration temperature T1 in the T0 and continuously carrying out a certain infiltration time T1 to enable the supercritical fluid to infiltrate into the composite fiber and reach a certain content; c) Foaming and crimping the composite fiber infiltrated by the supercritical fluid in the step b), wherein the step c) comprises c-1) after reaching the infiltration time T1, reaching a phase separation temperature T2 within a heating time T2, wherein the phase separation temperature T2 is lower than the softening point of the first component and higher than the softening point of the second component, c-2) maintaining the phase separation time T3 at the phase separation temperature T2 to finish the phase separation and form a potential foaming point inside the composite fiber, c-3) maintaining the phase separation temperature T2, reducing the pressure of the composite fiber to a foaming background low pressure P2 through a pressure release time T4, c-4) maintaining the foaming background low pressure P2 and the phase separation temperature T2 through a foaming time T5, realizing foaming, further increasing the difference of the two components through the difference of expansion rates, and enhancing the crimping; d) Shaping the foamed and crimped composite fiber of step c).
  2. 2. The method of making crimped composite fibers according to claim 1, wherein the first component and the second component are selected from polyesters or polyamides, provided that the first component and the second component are homologs having an intrinsic viscosity that differs by 0.30-1.05 dl/g, the first component and the second component being bilaterally distributed over the cross section of the composite fiber.
  3. 3. The method of producing crimped composite fibers according to claim 1, wherein the mass ratio of the first component to the second component is 1:0.5 to 1.2.
  4. 4. The method of making crimped composite fibers according to claim 1, wherein the supercritical fluid is selected from CO 2 、N 2 or a combination thereof.
  5. 5. The method of producing crimped composite fibers according to claim 1, wherein the setting in step d) is performed at a temperature of 150 to 160 ℃ for 10 to 30 minutes.
  6. 6. A crimped composite fiber produced by the production method according to any one of claims 1 to 5, characterized in that the crimped composite fiber comprises a first component and a second component, wherein the second component has a larger expansion ratio than the first component, so that the composite fiber has a crimped three-dimensional structure.

Description

Method for producing crimped composite fiber and crimped composite fiber obtained thereby Technical Field The invention relates to a preparation method of a crimped composite fiber and the crimped composite fiber obtained by the method, in particular to a preparation method of the crimped composite fiber based on a supercritical fluid foaming technology, which realizes optimization of a fiber crimp structure and remarkable improvement of heat retention property by controlling temperature and pressure conditions. Background Crimping of the fibers can increase friction and cohesion between the fibers, thereby improving spinnability of the staple fibers. Meanwhile, the curling can increase the transverse occupied space and the longitudinal elastic elongation of the fiber, and regulate and control the ventilation, conduction or isolation and the like of the fiber aggregate, so that the elasticity and warmth retention of the fiber aggregate are improved. There are generally two main sources of fiber crimp, one is natural and one is artificially attached. For chemical fibers, the artificial additional crimp may be processed by thermo-mechanical deformation such as false twisting, braiding and unbinding, stuffer box, and gear shaping. In addition, two fiber-forming high polymer components with different heat shrinkage properties can be distributed on the cross section of the fiber side by utilizing the composite multifilament, so that a highly fluffy three-dimensional curled structure can be obtained after heating. Among such composite fibers, the PET/PTT parallel composite fibers are widely used in the textile field due to their excellent elasticity and crimping properties, because of their excellent properties and good interfacial compatibility with PET-generic polyester fibers. As in patent CN116971044a, a production method of a special double-component composite elastic fiber for a thermal fabric is disclosed, which mainly comprises the steps of respectively injecting a certain proportion of warm master batches into high-viscosity PTT and low-viscosity PET to form a high-viscosity mixture and a low-viscosity mixture, and carrying out drying treatment and then carrying out composite spinning to form the 8-shaped double-component fiber. CN117983153B discloses a polymerization reactor for high-viscosity PTT and a method for preparing melt direct spinning high-viscosity PTT/low-viscosity PET bicomponent elastic fiber. However, the traditional process is limited by the difference of the performances of the two components of the composite, the curvature of the fiber is low, and the thermal insulation performance is limited. The supercritical fluid has gas-like diffusivity and liquid-like dissolution capacity, and the properties of viscosity, dissolution capacity and the like related to density can be conveniently regulated and controlled along with the change of temperature and pressure. In recent years, supercritical fluid foaming technology has been used to improve the weight reduction and performance optimization of thermoplastic polymer materials such as PET, PLA, PP, but its application to the foaming of thermoplastic fibers, especially PET/PTT parallel composite fibers, has not yet been mature. Therefore, the invention provides a preparation method combining a supercritical fluid foaming technology and parallel composite fibers, aiming at realizing the improvement of the fiber rolling degree and the enhancement of the thermal insulation performance by regulating and controlling the technological parameters. Disclosure of Invention One aspect of the present invention relates to a method of making a crimped composite fiber, the method comprising the steps of: a) Providing a composite fiber comprising a first component and a second component in side-by-side combination; b) Performing supercritical fluid infiltration on the composite fiber in the step a); c) Foaming and crimping the composite fiber infiltrated with the supercritical fluid in step b); d) Shaping the foamed and crimped composite fiber of step c). In a preferred embodiment, the first component has a higher softening point than the second component. In a preferred embodiment, the first component and the second component are selected from polyesters (polyethylene terephthalate PET、‌ HYPERLINK "https://www.baidu.com/srsv_dl=re_dqa_generate&sa=re_dqa_generate&wd=PTT%E8%81%9A%E5%AF%B9%E8%8B%AF%E4%BA%8C%E7%94%B2%E9%85%B8%E4%B8%99%E4%BA%8C%E9%86%87%E9%85%AF&rsv_pq=9bb2e460000d8acc&oq=PTT%20%E8%81%9A&rsv_t=18e27ZSsBq7qGSrckXI07ENMeuqH7RnytOVZV8+ScyceG5Lw+3/23yU0RRaEZxJGSZ9seMURGnE&tn=62095104_9_oem_dg&ie=utf-8" \t "_blank" polytrimethylene terephthalate PTT, polybutylene terephthalate PBT, polylactic acid PLA, polybutylene succinate PBS, etc.) or polyamides (polyamide PA6, polyamide PA66, polyamide PA10, polyamide PA56, etc.), provided that the first component and the second component are homologs with an intrinsic viscosity difference of 0.30-1.05 dl/g (pr