Controlled skin formation for foamed extrudate
US7832998B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 2006 |
| Grant date | Nov 16, 2010 |
| Priority date | — |
| Expiry date | Sep 16, 2029 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/5254
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An extrusion apparatus is taught that employs a die adapter that is partially submerged in a heat transfer bath on a horizontal plane such that there is no air gap between the die extrusion aperture and the heat transfer bath. A porous dam is positioned between the die and the heat transfer bath. A heat insulating plate is positioned between the porous dam and the die to prevent the heat transfer medium from flowing onto the die. The heat insulating plate also prevents excessive cooling of the die tip thereby allowing the necessary precise thermal control over the extrudate skin formation to prevent melt fracture and form a low density extrudate with a smooth solid skin and inner foamed core.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.