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CN-121976319-A - Recyclable regenerated TPU spandex fiber and preparation method thereof

CN121976319ACN 121976319 ACN121976319 ACN 121976319ACN-121976319-A

Abstract

The invention discloses a recyclable regenerated TPU spandex fiber and a preparation method thereof, and belongs to the technical field of high polymer material recycling and chemical fiber manufacturing. The preparation method of the regenerated TPU spandex fiber comprises the following steps of carrying out melt granulation and filtration on a polyester type thermoplastic polyurethane reclaimed material to obtain purified TPU particles, then adding an alcoholysis agent to carry out alcoholysis reaction in a supercritical carbon dioxide solvent to obtain partially alcoholyzed TPU particles, adding an auxiliary agent to carry out plasticizing treatment to obtain a melt A, adding the auxiliary agent to carry out prepolymerization reaction on polyol and diisocyanate to obtain a prepolymer B, mixing the melt A and the prepolymer B, carrying out chain extension and polymerization reaction, carrying out melt filtration, granulating, drying and curing to obtain TPU slices, carrying out melt plasticization on the TPU slices, mixing with a cross-linking agent, and then extruding, cooling, oiling, traction, winding and curing to obtain the regenerated TPU spandex fiber.

Inventors

  • LANG TONG
  • JIA JIANHUA
  • SHI JIANWEI
  • JIA ZHENXING
  • ZHENG YUCHENG
  • LIU YAHUI
  • HUA BINGTAO
  • HOU JINGTIAN
  • Han Fengan
  • LI MINGLIU
  • CHENG ZHAOXIANG

Assignees

  • 河北邦泰氨纶科技有限公司
  • 保定邦泰高分子新材料有限公司

Dates

Publication Date
20260505
Application Date
20260127

Claims (10)

  1. 1. A method for preparing recyclable regenerated TPU spandex fiber, which is characterized by comprising the following steps: (1) Melting, granulating and filtering the recovered polyester thermoplastic polyurethane material to obtain purified TPU particles; Mixing the purified TPU particles with an alcoholysis agent, and carrying out alcoholysis reaction in a supercritical carbon dioxide solvent until the molecular weight of the TPU particles is 7-13 ten thousand, thereby obtaining partially-alcoholyzed TPU particles; (2) The TPU particles and the auxiliary agent which are partially alcoholyzed are subjected to plasticizing treatment at 170-210 ℃ through a single screw extruder to obtain a melt A; carrying out a prepolymerization reaction on polyol, diisocyanate and an auxiliary agent at 150-250 ℃ through a double-screw extruder to obtain a prepolymer B; Mixing the melt A with the prepolymer B, performing chain extension and polymerization reaction, and performing melt filtration, granulating, drying and curing to obtain TPU slices; (3) And (3) melting, plasticizing and extruding the TPU slices, mixing with a cross-linking agent, spinning to obtain primary fibers, and then cooling, oiling, traction, winding and curing to obtain the regenerated TPU spandex fibers.
  2. 2. The method according to claim 1, wherein the melting temperature of the melt granulation and filtration is 200 to 240 ℃ and the mesh number of the filter screen is 300 to 500 mesh.
  3. 3. The preparation method according to claim 1, wherein the alcoholysis agent is added in an amount of 150wt% of the purified TPU particles, and the alcoholysis agent is one or more of ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol and 1, 6-hexanediol.
  4. 4. The method according to claim 1, wherein the alcoholysis reaction is carried out at a temperature of 100 to 160 ℃ and a pressure of 7.5 to 12mpa.
  5. 5. The preparation method of claim 1, wherein the mixture further comprises a glycol chain extender, and the molar ratio of the polyol to the glycol chain extender to the diisocyanate is 0-1:0-1.5:1.2-5, and is not 0; The polyol is polyether polyol and/or polyester polyol, and the number average molecular weight of the polyol is 1000-4000; The dihydric alcohol chain extender is one or more of ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 5-pentanediol and 1, 6-hexanediol; the diisocyanate is one or more of diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate and hexamethylene diisocyanate.
  6. 6. The method according to claim 1, wherein the mass ratio of the melt A to the prepolymer B is 4-9:1-6.
  7. 7. The method according to claim 1, wherein the temperature of the chain extension and polymerization reaction is 200 to 230 ℃.
  8. 8. The preparation method according to claim 1, wherein in the step (3), the curing relative humidity is 70-85%, the time is 5-10 days, and the adding amount of the crosslinking agent is 2-10 wt% of the TPU slices.
  9. 9. The preparation method of the melt A according to claim 1, wherein the addition amount of the auxiliary agent is 0.1-3wt% of the partially alcoholized TPU particles in the preparation of the melt A, the addition amount of the auxiliary agent is 0.1-3wt% of the mixture in the preparation of the prepolymer B, and the auxiliary agent comprises 0-50wt% of an antioxidant, 0-50wt% of an anti-hydrolysis agent, 0-50wt% of an ultraviolet absorber and 0-50wt% of a lubricant in terms of mass ratio.
  10. 10. A regenerated TPU spandex fiber obtained by the method of any one of claims 1-9.

Description

Recyclable regenerated TPU spandex fiber and preparation method thereof Technical Field The invention relates to the technical field of high polymer material recycling and chemical fiber manufacturing, in particular to a recyclable regenerated TPU spandex fiber and a preparation method thereof. Background With the widespread popularity of sustainable concepts, the green transformation of the textile industry has become a necessary trend. Spandex, which is a typical representation of highly elastic fibers, is of great interest in recycling and reuse technology. At present, the preparation of regenerated spandex mainly depends on two technical paths, namely a physical melting and re-spinning method, for example, a method for compensating performance loss of reclaimed materials by directly adding a cross-linking agent and an enhancer into waste spandex filaments described in CN 118880488A patent, but introducing a cross-linking system before spinning can cause great challenges for subsequent melt spinning, and a chemical degradation method, wherein the method is finished by depolymerizing waste spandex into monomers and then carrying out polymerization again after purification, but has the limitations of complex process flow and higher cost, and is difficult to realize in scale. Under the background, researchers have begun to explore new ways of preparing regenerated spandex from Thermoplastic Polyurethane (TPU) reclaimed materials of widely available and homogeneous polyurethanes. Because the TPU and the spandex have similarity in chemical structure, the TPU and the spandex have the potential to replace partial synthetic raw materials in theory, particularly, the TPU is converted into an intermediate with proper molecular weight through an alcoholysis technology, and the molecular structure of the TPU is further adjusted, so that new possibility is provided for preparing the high-performance regenerated spandex. However, this path still faces many challenges. For example, traditional alcoholysis processes are complex and have high carbon emissions, and methods as reported in CN 111902446A have essentially lost the recovery value of TPU in practical applications. In addition, how to stably embed the TPU intermediate after alcoholysis into a new polyurethane molecular chain and construct a perfect microphase separation structure (the structure is the key of spandex elasticity) becomes a technical difficulty. If the process is improperly matched, the problems of structural defects, gel and the like are easily caused, and the spinnability and the final quality of the fiber are further affected. Therefore, how to develop a method for preparing the high-performance regenerated TPU spandex fiber, which has simple process flow and environmental protection, and has important technical and economic values. Disclosure of Invention The invention aims to provide a recyclable regenerated TPU spandex fiber and a preparation method thereof, which are used for solving the problems in the background technology. According to the invention, through a specific 'partial alcoholysis-prepolymer chain extension' molecular structure design, the molecular chain structure of the recovered TPU is effectively reconstructed, so that the recovered TPU is suitable for melt spinning of high-performance spandex, and the mechanical property and the elastic recovery rate of the obtained product are comparable to those of the virgin spandex. In order to achieve the above purpose, the present invention provides the following technical solutions: The invention provides a preparation method of recyclable regenerated TPU spandex fiber, which comprises the following steps: (1) Melting granulation and filtration are carried out on a polyester type thermoplastic polyurethane reclaimed material (reclaimed TPU) to obtain purified TPU particles; Mixing the purified TPU particles with an alcoholysis agent, and carrying out alcoholysis reaction in a supercritical carbon dioxide solvent until the molecular weight of the TPU particles is 7-13 ten thousand, preferably 10-12 ten thousand, so as to obtain partially-alcoholyzed TPU particles; (2) The TPU particles and the auxiliary agent which are partially alcoholyzed are subjected to plasticizing treatment at 170-210 ℃ through a single screw extruder to obtain a melt A; carrying out a prepolymerization reaction on polyol, diisocyanate and an auxiliary agent at 150-250 ℃ through a double-screw extruder to obtain a prepolymer B; Mixing the melt A with the prepolymer B, performing chain extension and polymerization reaction, and performing melt filtration, granulating, drying and curing to obtain TPU slices; (3) And (3) melting, plasticizing and extruding the TPU slices, mixing with a cross-linking agent, spinning to obtain primary fibers, and then cooling, oiling, traction, winding and curing to obtain the regenerated TPU spandex fibers. Preferably, the polyester thermoplastic polyurethane reclaimed material is on