POLYETHYLENE FOR SUPERIOR SHEET EXTRUSION THERMOFORMING PERFORMANCE

摘要

A method of forming a thermoformed article may include melt extruding polyethylene to form an extruded sheet. The rheological breadth parameter of the polyethylene may change by no more than about 5% after extrusion relative to the rheological breadth parameter of the polyethylene prior to extrusion. The extruded sheet may be thermoformed within a mold to form the thermoformed article. During thermoforming, the extruded sheet may be subjected to solid-state stretching in one or more directions. The thermoformed article may be retrieved from the mold. The polyethylene may have a rheological breadth parameter of from 0.20 to 0.40, a multimodal molecular weight distribution, a polydispersity (Mw/Mn) of from 5 to 18, a density ranging from 0.940 to 0.970 g/cc, may exhibit tensile strain-hardening, or combinations thereof.

主权项

1. A method comprising:
melt extruding a polyethylene comprising a rheological breadth parameter of from 0.20 to 0.40, a multimodal molecular weight distribution, and a polydispersity (Mw/Mn) of from 5 to 18 to form an extruded sheet, wherein the rheological breadth parameter of the polyethylene changes by no more than about 5% after extrusion relative to the rheological breadth parameter of the polyethylene prior to extrusion; thermoforming the extruded sheet within a mold to form a thermoformed article, wherein, during the thermoforming of the extruded sheet, the extruded sheet is subjected to solid-state stretching in one or more directions; and retrieving the thermoformed article from the mold.