Process for making puncture resistant, heat-shrinkable films containing very low density polyethylene

US4976898A · kind A · utility

Assignee

• Viskase Companies, Inc. · US

Inventors

• Stanley Lustig · Park Forest, US
• Nancy M. Mack · Chicago, US
• Jeffrey M. Schuetz · Florence, US
• Stephen J. Vicik · Darien, US

Key dates

• Filing date: Jul 25, 1989
• Grant date: Dec 11, 1990
• Expiry date: Jul 25, 2009

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B32B27/08
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Method of manufacturing a heat shrinkable biaxially oriented thermoplastic film by extruding a primary tube including very low density polyethylene (VLDPE), heating the primary tube and biaxially stretching the heated primary tube using a double bubble method to form a tube which is heat shrinkable from about 30% to about 50% in at least one of the transverse and machine directions.