Polymer extrusion process
US12318985B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2021 |
| Grant date | Jun 3, 2025 |
| Priority date | — |
| Expiry date | Sep 29, 2041 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2105/0094
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In the manufacture of extruded polymers there are a number of surface defects referred to as sharkskin, snakeskin and orange peel which all generally relate to the rheology of the polymer melt. A severe form of surface defect is “melt fracture” which is believed to result when the shear rate at the surface of the polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally can't flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs generally resulting in a severe loss of surface properties for the extrudate. A polymer extension process is disclosed wherein these undesirable surface defects are eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.