Multilayer, stretched heat-sealable polypropylene film

US5441806A · kind A · utility

Assignee

• Wolff Walsrode AG · DE

Inventors

• Rainer Brandt · Walsrode, DE
• Ulrich Reiners · Neuenkirchen, DE
• Anton Krallmann · Bad Fallingbostel, DE
• Jürgen Bohner · Bad Waldsee, DE
• Neele Neelen · Einbeck, DE

Key dates

• Filing date: Mar 3, 1994
• Grant date: Aug 15, 1995
• Expiry date: Mar 3, 2014

Classification

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

Abstract

The invention relates to an oriented sealable polypropylene film combining an improved water vapor barrier effect with considerably reduced global migration for packaging purposes and having the following layer structure: EQU A B C B A where PA1 a) C is a base layer of polypropylene and a hydrocarbon resin which has a molecular weight of up to about 2000 g/mol and a softening point above 130.degree. C., PA1 b) the B's are jacket layers of highly isotactic polypropylene (isotacticity >94%) free from hydrocarbon resin, the ratio between the thickness of a jacket layer and the thickness of the base layer being between 0.01 and 0.1, PA1 c) the A's are two surface layers of a heat-sealable polyolefin copolymer or terpolymer, these surface layers containing at least one antiblocking agent, a lubricant and an antistatic agent.