Multilayer, stretched heat-sealable polypropylene film

US5441807A · kind A · utility

Assignee

• Wolff Walsrode AG · DE

Inventors

• Rainer Brandt · Walsrode, DE
• Ulrich Reiners · Neuenkirchen, DE
• Anton Krallmann · Bad Fallingbostel, DE
• Neele Neelen · Einbeck, DE
• Jürgen Bohner · Bad Waldsee, 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 sealable polypropylene films having an improved water vapor barrier effect through the following layer structure: EQU ABCBA where PA1 a) C is the base layer of highly isotactic polypropylene with an isotacticity of >94% 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 two jacket layers of highly isotactic polypropylene (isotacticity >94%) free from hydrocarbon resin, the ratio between the thickness of the 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 homopolymer, copolymer or terpolymer, these surface layers containing at least one antiblocking agent, a lubricant and an antistatic agent.