Multiple layer sheet materials, and packages, and methods and apparatus for making
US5236642A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1989 |
| Grant date | Aug 17, 1993 |
| Priority date | — |
| Expiry date | Dec 28, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB32B2439/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Method, apparatus, and films, related to coextrusion of heat-sensitive polymer materials. The sensitive melt stream element (12) is encapsulated in a second polymeric melt stream element (16). Transport means (36) is preferably employed between the encapsulating means (20) and the die (42). A third melt stream element (68) is joined to one or both opposing surfaces (70) of the second melt stream element (16) between the encapsulating means (20) and the die (42). In the die (42) the encapsulated melt stream element (12) becomes an interior layer (46) between encapsulating layers (48A, 48B) derived from the second melt stream element (16). The third melt stream element (68) forms layers (72, 74) positioned outwardly of the encapsulating layers (48A, 48B). The positioning, on the interior of the extrudate, of edges (54) of layer (46) is adjusterd independently of the combined thicknesses of a layer derived from the third melt stream element (68) and an adjacent layer (48).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.