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CN-122011374-A - Method for preparing high-heat-resistance high-transparency polyester amide by recycling waste PET

CN122011374ACN 122011374 ACN122011374 ACN 122011374ACN-122011374-A

Abstract

The invention provides a method for preparing high-heat-resistance and high-transparency polyester amide by recycling waste PET, which comprises the steps of (1) conducting alcoholysis reaction on a first raw material system comprising waste PET, an alcoholysis agent and an alcoholysis catalyst to obtain an alcoholysis system, (2) conducting ammonolysis reaction on a second raw material system comprising the alcoholysis system, a diamine ammonolysis agent and the ammonolysis catalyst to obtain an ammonolysis system, (3) conducting exchange reaction on the ammonolysis system to obtain an exchange system and an alcoholysis agent recycling system, wherein the exchange reaction comprises transesterification reaction and/or amide exchange reaction, and (4) conducting polymerization reaction on a system to be polymerized comprising the exchange system to obtain regenerated polyester amide. The PET recycling method provided by the invention is simple and efficient, and can effectively upgrade waste polyester into high-added-value and high-functional materials.

Inventors

  • QU ZHENG
  • DING MENGRU
  • Wang Shuaici
  • ZHU YIFAN
  • XU WENQING
  • LIU RUIQI
  • LIU YANYUAN

Assignees

  • 浙江恒逸石化研究院有限公司

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. The method for preparing the polyesteramide by recycling the waste PET is characterized by comprising the following steps: (1) Carrying out an alcoholysis reaction on a first raw material system comprising waste PET, an alcoholysis agent and an alcoholysis catalyst to obtain an alcoholysis system; (2) Carrying out an aminolysis reaction on a second raw material system comprising the alcoholysis system, a diamine aminolysis agent and an aminolysis catalyst to obtain an aminolysis system; (3) Carrying out exchange reaction on the aminolysis system to obtain an exchange system and an alcoholysis agent recovery system, wherein the exchange reaction comprises transesterification and/or amide exchange reaction; (4) Polymerizing a system to be polymerized comprising the exchange system to obtain regenerated polyesteramide; The aminolysis system comprises bis (2-hydroxyethyl) terephthalate and a compound shown in a formula 1, Formula 1; n is an integer of 1 to 5, R is derived from the diamine aminolysis agent, and R is a C10-C15 alicyclic ring.
  2. 2. The method for preparing polyesteramide by recycling waste PET according to claim 1, wherein the diamine aminolysis agent has a structure shown in formula 2, NH 2 -R-NH 2 formula 2.
  3. 3. The method for preparing polyesteramide by recycling waste PET according to claim 1 or 2, wherein the diamine aminolysis agent comprises at least one of 4,4' -diaminodicyclohexylmethane, isophoronediamine, 3' -dimethyl-4, 4-diaminodicyclohexylmethane, and 4,4' -isopropyldicyclohexylamine.
  4. 4. A method for recycling waste PET to produce polyesteramide according to any of claims 1-3, wherein the amount of the diamine-based aminolysis agent is 30% -90% of the amount of terephthalic acid in the waste PET.
  5. 5. The method for producing polyesteramide by recycling waste PET according to any of claims 1 to 4, wherein in the alcoholysis reaction, the reaction temperature is 200 ℃ to 240 ℃ and the time is 1h to 2h, and/or, In the aminolysis reaction, the reaction temperature is 200-220 ℃ and the time is 2-6 h, and/or, In the exchange reaction, the reaction temperature is 250-260 ℃, the time is 2-5 h, the pressure is 50-150 kPa, and/or, In the polymerization reaction, the reaction temperature is 265-280 ℃, the time is 2-5 h, the pressure is 20-60 Pa, and/or, The method also comprises the step of returning the alcoholysis agent recovery system to participate in the alcoholysis reaction.
  6. 6. The method for producing polyesteramide by recycling waste PET according to claim 1 to 5, wherein the alcoholysis agent comprises ethylene glycol and/or, The alcoholysis catalyst comprises at least one of zinc acetate, sodium acetate and cobalt acetate and/or, The aminolysis catalyst comprises at least one of 1,5, 7-triazabicyclo [4.4.0] decen-5-ene, tetramethyl guanidine, 1, 8-diazabicyclo [5.4.0] undec-7-ene, and/or, The mass ratio of the alcoholysis agent to the waste PET is (1-3) 1 and/or, The mass ratio of the alcoholysis catalyst to the waste PET is 0.1% -0.5%, and/or, The mass ratio of the aminolysis catalyst to the waste PET is 0.5% -1.0%.
  7. 7. The method for preparing polyesteramide by recycling waste PET according to any of claims 1-6, wherein the system to be polymerized further comprises one or more of polymerization catalyst, stabilizer and antioxidant, wherein the polymerization catalyst comprises one or more of antimony trioxide, antimony glycol, titanium glycol, tetrabutyl titanate, tetraisopropyl titanate and germanium dioxide, and/or, The stabilizer comprises one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphite, and/or, The antioxidant comprises one or more of pentaerythritol tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], N-stearyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, N' -bis- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexamethylenediamine, bis (2, 4-dicumylphenyl) pentaerythritol-diphosphite and tris [2, 4-di-tert-butylphenyl ] phosphite.
  8. 8. The method for recycling and preparing polyesteramide from waste PET according to claim 7, wherein in the polymerization catalyst, the mass ratio of the metal element to the regenerated polyesteramide is 5 ppm-150 ppm in terms of metal element, the mass ratio of the stabilizer to the regenerated polyesteramide is 5 ppm-25 ppm in terms of phosphorus element, and the mass ratio of the antioxidant to the regenerated polyesteramide is 100 ppm-3000 ppm.
  9. 9. A recycled polyester amide, characterized in that it is obtained by the process for recycling waste PET according to any one of claims 1 to 8.
  10. 10. The recycled polyester amide of claim 9, wherein the recycled polyester amide has a heat distortion temperature of 80.4 ℃ to 161.3 ℃ and a transmittance of 87.1% to 93.6%.

Description

Method for preparing high-heat-resistance high-transparency polyester amide by recycling waste PET Technical Field The invention relates to the technical field of high polymer materials, in particular to a method for preparing high-heat-resistance and high-transparency polyester amide by recycling waste PET. Background Polyethylene terephthalate (PET) is a widely used general-purpose plastic, and the huge consumption of products in the fields of packaging, spinning and the like brings about corresponding environmental pressure. Waste PET is difficult to degrade in natural environments, improper disposal can cause long-term "white pollution", and its production is dependent on petroleum resources. Therefore, the development of efficient PET chemical recovery technology depolymerizes the PET chemical recovery technology into original monomers or intermediates to realize closed loop circulation, and has urgent demands and important significance for reducing environmental pollution, saving fossil resources and promoting sustainable development of plastic economy. However, the current commercial route for chemical depolymerization recovery of PET still faces significant challenges. On the one hand, the existing depolymerization process is complex in process, and often involves multiple steps of reactions and complicated separation and purification steps, so that the energy consumption is high, the operation requirements are strict, and the overall efficiency and the economy are difficult to be compatible. On the other hand, the regenerated polymer obtained by repolymerization of the monomer or intermediate recovered by the prior art is generally significantly inferior to petroleum-based virgin polymer in key physical and chemical properties, especially the indexes such as heat resistance and optical transparency are significantly reduced, and the strict requirements of the fields such as high-end packaging and high-performance fibers on the material quality are difficult to meet. The method can degrade and use a plurality of regenerated PET, can not realize closed loop circulation with high added value, and restricts the economic feasibility and large-scale popularization of the chemical recovery process. Therefore, aiming at the core problems of complex process and poor material properties (especially heat resistance and optical properties) of the depolymerized product after the depolymerization of the existing PET depolymerization technology, development of a novel depolymerization and refining method which is more concise, efficient and capable of maintaining the structural integrity of the product with high quality is needed. Disclosure of Invention The invention provides a method for preparing high-heat-resistance and high-transparency polyester amide by recycling waste PET, which is suitable for recycling waste PET, and has the advantages of simplicity, high efficiency and capability of effectively upgrading waste polyester into high-added-value and high-functional materials. The invention provides a method for preparing high heat-resistant and high transparent polyester amide by recycling waste PET, which comprises the steps of (1) conducting alcoholysis reaction on a first raw material system comprising waste PET, an alcoholysis agent and an alcoholysis catalyst to obtain an alcoholysis system, (2) conducting ammonolysis reaction on a second raw material system comprising the alcoholysis system, a diamine amine-based ammonolysis agent and an ammonolysis catalyst to obtain an ammonolysis system, (3) conducting exchange reaction on the ammonolysis system to obtain an exchange system and an alcoholysis agent recycling system, wherein the exchange reaction comprises transesterification reaction and/or amide exchange reaction, (4) conducting polymerization reaction on a system to be polymerized comprising the exchange system to obtain regenerated polyester amide, the ammonolysis system comprises bis (2-hydroxyethyl) terephthalate and a compound shown in a formula 1, Formula 1; n is an integer of 1 to 5, R is derived from the diamine aminolysis agent, and R is a C10-C15 alicyclic ring. Optionally, the diamine aminolysis agent has a structure shown in a formula 2, and NH 2-R-NH2 is shown in a formula 2. Optionally, the diamine-based aminolysis agent comprises at least one of 4,4' -diamino dicyclohexylmethane, isophorone diamine, 3' -dimethyl-4, 4-diamino dicyclohexylmethane, and 4,4' -isopropyl dicyclohexylamine. Optionally, the amount of the diamine aminolysis agent is 30% -90% of the amount of terephthalic acid in the waste PET. Optionally, the reaction temperature is 200-240 ℃ and the time is 1-2 h, and/or the reaction temperature is 200-220 ℃ and the time is 2-6 h in the alcoholysis reaction, and/or the reaction temperature is 250-260 ℃ and the time is 2-5 h in the exchange reaction, and the pressure is 50 kPa-150 kPa, and/or the reaction temperature is 265-280 ℃ and the time is 2-5 h and the pressure is 20