Polyethylene for superior sheet extrusion thermoforming performance
US10414086B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 2016 |
| Grant date | Sep 17, 2019 |
| Priority date | — |
| Expiry date | Sep 5, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2323/06
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.