Blown film extrusion
US4632801A · kind A · utility
38Cited by
12References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1985 |
| Grant date | Dec 30, 1986 |
| Priority date | — |
| Expiry date | Sep 23, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/0019
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of blown film extrusion of polyolefins having high elongational viscosity which is independent of applied stress, and high melt strength wherein a first air ring is disposed adjacent an extrusion die to assist in the formation and stability of a stalk bubble configuration, and a second air ring is disposed downstream of the first air ring to assist in controlled expansion of the bubble at a point where the bubble has dissipated its melt elasticity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.