Biaxially oriented opaque polyolefin multi-layer film

US4983447A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

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

Key dates

• Filing date: Sep 11, 1987
• Grant date: Jan 8, 1991
• Expiry date: Sep 11, 2007

Classification

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

Abstract

An opaque polyolefin film having a base layer composed essentially of propylene polymers and having sealing layers present on both sides, composed essentially of sealable olefin polymers, is disclosed. From about 0.2% to 1.5% by weight, relative to the layer of polydialkylsiloxane is incorporated in one of the two sealing layers, and this layer has not been subjected to corona treatment. The other sealing layer has been subjected to corona treatment and has polydialkylsiloxane, not incorporated, but present on the outer surface of this layer, the polydialkylsiloxane having been transferred to this layer by contact between the sealing layer in which polydialkylsiloxane is incorporated. The relative polydialkylsiloxane occupancy of this layer, which is determined by means of ESCA spectroscopy, is not more than 15. The three-layer opaque polyolefin film is prepared by the coextrusion process. It is particularly suitable for use as a packaging film on high-speed packaging machines.