Clear film extrusion from an annular die
US5322664A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 2, 1993 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Feb 2, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2826
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method and apparatus is provided for forming clear shrinkable film material for use as labels on containers. A blend of general purpose polystryene and styrene-butadiene or styrene butyl acrylate is extruded from an annular extruder die orifice to form a frustoconical tube which is stretched before cooling air is applied to form a clear film that has machine direction orientation and cross direction orientation that can be used as a shrinkable label on containers. As the tube is extruded, it is shielded from cooling air which is applied downstream from the extruder die orifice. The apparatus shields the hot annular extruded material adjacent the die orifice. The air is supplied downstream from an annular air orifice which is designed with a taper that allows ambient air to be freely drawn in and eliminates what would be a negative pressure zone immediately downstream of the air orifice while eliminating air turbulence and improving cooling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.