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CN-122011355-A - Regenerated PET material and preparation method and application thereof

CN122011355ACN 122011355 ACN122011355 ACN 122011355ACN-122011355-A

Abstract

The invention discloses a regenerated PET material and a preparation method and application thereof. The preparation method of the regenerated PET material comprises the following steps of carrying out a step of heating and pre-crystallizing treatment on the regenerated PET slices, carrying out solid-phase tackifying after the reaction extrusion by combining a compound main catalyst, wherein the prepared regenerated PET material has higher intrinsic viscosity, lower yellowness and higher tensile strength, and the intrinsic viscosity of the prepared regenerated PET material is not lower than 0.66 dL/g, the change value of the yellowness is not higher than 3.5, and the tensile strength is not lower than 50MPa.

Inventors

  • LUO SHIMIN
  • YE NANBIAO
  • LI JIANJUN
  • LIU SIYANG
  • GUAN HUANXIANG
  • LI FAN

Assignees

  • 金发科技股份有限公司
  • 金发环保科技有限公司

Dates

Publication Date
20260512
Application Date
20260123

Claims (10)

  1. 1. The preparation method of the regenerated PET material is characterized by comprising the following steps of: S1, heating and pre-crystallizing a regenerated PET slice stage to obtain a pre-crystallized product; S2, mixing the pre-crystallized product obtained in the step S1 with a main catalyst, a chain extender and a cocatalyst, and performing reaction extrusion to obtain pre-tackifying particles; s3, carrying out solid-phase tackifying and post-treatment on the pre-tackified particles obtained in the step S2 to obtain a regenerated PET material; Wherein the main catalyst comprises a complex of a titanate compound and nano-silica.
  2. 2. The preparation method according to claim 1, wherein the step S1 is performed by heating and pre-crystallizing the sliced regenerated PET resin at 85-105 ℃ for 2-3 hours and then crystallizing the sliced regenerated PET resin at 125-175 ℃ for 1.5-2 hours.
  3. 3. The process according to claim 1, wherein the procatalyst in step S2 satisfies at least one of the following two conditions: (a) The main catalyst is 0.15-0.3wt% of the pre-crystallized product in the step S1; (b) The mass ratio of the titanate compound to the nano silicon dioxide in the main catalyst is (3-6): 1.
  4. 4. The method of claim 1, wherein at least one of the following two conditions is satisfied: (a) The cocatalyst in the step S2 is 0.08-0.15 wt% of the pre-crystallized product in the step S1, and comprises phosphate and montmorillonite, preferably, the mass ratio of the phosphate to the montmorillonite in the cocatalyst is 1:1.5-1:2.5; (b) The chain extender in the step S2 is 0.08-0.5wt% of the pre-crystallized product in the step S1, and comprises one or more of isocyanate compounds, epoxy compounds and oxazoline compounds.
  5. 5. The method of claim 1, wherein step S2 further comprises 0.08 to 0.12wt% of an antioxidant as a pre-crystallized product of step S1.
  6. 6. The preparation method according to claim 1, wherein the reactive extrusion in the step S2 is that a feeding section is preheated, a melting section is melted, mixed and activated, a mixing section is sheared at a high speed, and a machine head section is extruded stably; preferably, the preheating temperature of the feeding section is 165-175 ℃; The temperature of the melting section for melting, mixing and activating is 245-255 ℃; the high-speed shearing temperature of the mixing section is 230-250 ℃; the temperature of stable extrusion of the machine head section is 248-255 ℃, and the pressure of the machine head is 11-14 MPa.
  7. 7. A recycled PET material, characterized in that it is produced by the production method according to any one of claims 1 to 6.
  8. 8. The recycled PET material of claim 7, wherein the intrinsic viscosity of the recycled PET material is not less than 0.66 dL/g and the tensile strength is not less than 50MPa, preferably the intrinsic viscosity of the recycled PET material is 0.7-0.85 dl/g and the tensile strength is 51-66 MPa.
  9. 9. Use of the recycled PET material of claim 7 or 8 for the manufacture of packaging products, textile fibres or engineering plastic articles.
  10. 10. A plastic article produced from the recycled PET material of claim 7 or 8.

Description

Regenerated PET material and preparation method and application thereof Technical Field The invention belongs to the technical field of high polymer material recovery and modification, and particularly relates to a regenerated PET material, and a preparation method and application thereof. Background Polyethylene terephthalate (PET resin) is one of the common plastics widely used, has better rigidity and wear resistance, and the prepared product has good surface gloss and high transparency. However, the recycled PET resin has lower intrinsic viscosity after being recycled, which leads to serious defects of inherent mechanical property, heat resistance and processing property of the material, and jointly limits the high-value application of the recycled PET. It cannot meet the technological requirements of blow molding, foaming and the like, and is difficult to apply to environments with standard strength or heat resistance, so that the environment can be degraded for use in most cases. In the prior art, the intrinsic viscosity of the regenerated PET material is often improved through solid-phase tackifying, but the tackifying rate is slow, long time is required, the energy consumption is high, and the yellowing degree of the regenerated PET material is also increased, so that the regenerated PET material cannot be used for manufacturing water bottles and beverage bottles with high requirements on transparency and appearance, and outdoor building materials and automobile exterior trim parts with excellent weather resistance and durability. Disclosure of Invention The invention aims to overcome the defect that the regenerated PET material in the prior art cannot have high viscosity, low yellowness and high mechanical properties, and provides the regenerated PET material. Another object of the present invention is to provide a method for preparing the recycled PET material. It is a further object of the present invention to provide the use of said recycled PET material. In order to achieve the above purpose, the invention adopts the following technical scheme: A recycled PET material, which is produced from recycled PET chips, and has an intrinsic viscosity of not less than 0.66 dL/g, a change in yellowness value of not more than 3.5, and a tensile strength of not less than 50MPa. The intrinsic viscosity of the recycled PET material described herein is not less than 0.66dL/g, such as, but not limited to, not less than 0.66dL/g, 0.68dL/g, 0.7dL/g, 0.72dL/g, 0.75dL/g, 0.78dL/g, 0.8dL/g, 0.82dL/g, 0.85dL/g, 0.88dL/g, or 0.9dL/g, etc., and specific point values between the above point values, are limited to space and for brevity, the specific point values included in the range are not exhaustive. Preferably, the intrinsic viscosity of the recycled PET material is 0.7-0.85 dL/g. Specifically, the test standard of the intrinsic viscosity of the regenerated PET material is GB/T1632.5-2008. The change in yellowness value of the recycled PET material of the present invention is not higher than 3.5, such as, but not limited to, not higher than 3.5, 3.4, 3.3, 3.2, 3.1, 3, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2, 1.9, or 1.8, etc., and the specific point values between the above point values, are limited to a spread and for brevity, the specific point values included in the range are not exhaustive. Preferably, the change of the yellowness value of the regenerated PET material is 2-3.4. In particular, the yellowness of the recycled PET material was tested according to standard GB/T39822-2021. In the present invention, the change in the yellowness value of the recycled PET material=the yellowness of the recycled PET material-the yellowness of the recycled PET slice. The tensile strength of the recycled PET material of the present invention is not lower than 50MPa, such as but not limited to not lower than 50MPa、50.5MPa、51MPa、51.5MPa、52MPa、52.5MPa、53MPa、53.5MPa、54MPa、54.5MPa、55MPa、55.5MPa、56MPa、56.5MPa、57MPa、57.5MPa、58MPa、58.5MPa、59MPa、59.5MPa、60MPa、60.5MPa、61MPa、61.5MPa、62MPa、62.5MPa、63MPa、63.5MPa、64MPa、64.5MPa、65MPa、65.5MPa、66MPa、66.5MPa MPa or 67MPa, etc., and the specific point values between the above point values, are for the sake of brevity and for the sake of brevity, the specific point values included in the ranges are not exhaustive. Preferably, the tensile strength of the regenerated PET material is 51-66 MPa. In particular, the tensile strength of the recycled PET material is tested according to standard GB/T1040.2025. The invention also provides a preparation method of the regenerated PET material, which comprises the following steps: S1, heating and pre-crystallizing a regenerated PET slice stage to obtain a pre-crystallized product; S2, mixing the pre-crystallized product obtained in the step S1 with a main catalyst, a chain extender and a cocatalyst, and performing reaction extrusion to obtain pre-tackifying particles; s3, carrying out solid-phase tackifying and post-treatment on the pre-tackified par