Bottle grade r-PET from Mixed PET and PETG Recycling

VALUE PROPOSITION

This technology is a process for converting mixed thermoformed recycled PETG and bottle recycled PET into bottle-grade recycled PET for use in new bottles or other plastic products.

INTRODUCTION

Polyethylene terephthalate (PET) and polyethylene terephthalate glycol-modified (PETG) are common thermoplastics that are used for a wide variety of applications. They are clear and work well in products like bottles and food containers, however they have different thermal properties which can cause issues when recycling them together. PETG melts at much lower temperatures than PET, and molten PETG can clump together and clog up recycling machinery. Increases in PETG recycling in recent years naturally means more PETG materials are mixed with PET post-consumer products, further increasing the challenge ever year.

DESCRIPTION OF TECHNOLOGY

This invention uses melt-processing of mixed r-PETG and r-PET flakes to make pellets with uniform thermal properties and densities. The intrinsic viscosity of the r-PETG material is increased to match that of the r-PET material using chain extenders during the melt-processing step and various catalysts are used to also upgrade the properties of the resulting bottle grade r-PET resin. Additionally, further upgrading of the material properties is done using solid state polymerization. During this step, the molecular weight, density, and viscosity of the polymers or blends are increased. Transesterification of in situ copolymers during melt-processing can also help improve the mechanical strength of the bottle-grade r-PET product.

BENEFITS

  • Improves the quality of r-PET from mixed PET and PETG streams by reducing material clumping
  • Removes the need for costly and time-consuming presorting steps for post-consumer plastics prior to recycling
  • Increases the ability to manage the ever increasing presence of PETG materials in post-consumer PET plastics

APPLICATIONS

  • Recycling mixed streams of both thermoformed PETG and PET plastics into bottle grade r-PET

PATENT STATUS

Patent pending

LICENSING RIGHTS

Full licensing rights available

INVENTORS

Dr. Muhammad Rabnawaz

TECH ID

TEC2021-0099

Patent Information:

For Information, Contact:

Jon Debling
Technology Manager
Michigan State University
deblingj@msu.edu
Inventors:
Muhammad Rabnawaz
Keywords: