Patent ID: 11872797
Assignee: MUCELL EXTRUSION, LLC
Field: Other special machines (Mechanical engineering)
Classification: CPC B  C | IPC B

Claim 0:
1. A method of making a multilayer foam sheet comprising:
providing a co-extrusion system comprising at least two single screw extruders;
feeding low I.V. polyester feedstock comprising polyester flakes from recycled sources, wherein up to 100% of the polyester in the feedstock comprises polyester flakes from recycled sources, into one of the extruders, wherein the low I.V. polyester feedstock has an intrinsic viscosity (I.V.) of lower than 0.8 dL/g as measured by ASTM D4603-18;
introducing supercritical physical blowing agent into melted polyester feedstock in at least one of the extruders;
processing the polyester feedstock at a processing temperature in the range of 15% lower than the melting temperature and 15% higher than the melting temperature; and
coextruding the feedstock from the extruders of the co-extrusion system through a flat sheet die to make a multilayer foam sheet, wherein at least one layer is a foam layer comprising low I.V. polyester.