Sealable, transparent polyolefinic multilayer film

US4720420A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gunther Crass · Taunusstein, DE
• Lothar Bothe · Mainz, DE
• Siegfried Janocha · Wiesbaden, DE

Key dates

• Filing date: Nov 26, 1985
• Grant date: Jan 19, 1988
• Expiry date: Nov 26, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31913
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A sealable, transparent polyolefinic multilayer film composed of a polypropylene base layer, a non-sealable surface layer, and a sealable surface layer, and process therefor. The sealable surface layer has a low minimum sealing temperature and is made from a copolymer of propylene and ethylene or butene-1 units and/or a terpolymer of ethylene, propylene and butene-1 units. The non-sealable layer is a combination of a propylene homopolymer, a slip agent, and an anti-blocking agent. The process includes coextruding the three layers, biaxially stretching the coextruded film, and subjecting the non-sealable layer to a corona-discharge treatment.