Process for the production of a metallizable multiply film

US5096630A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Lothar Bothe · Mainz, DE
• Gunter Schloegl · Kelkheim, DE
• Guenther Crass · Taunusstein, DE
• Thomas Wilhelm · Taunusstein, DE

Key dates

• Filing date: Aug 29, 1990
• Grant date: Mar 17, 1992
• Expiry date: Aug 29, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31917
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process for producing a metallizable, sealable, biaxially stretch-oriented multi-ply film includes the steps of: providing melts of a predominantly polypropylene base layer, and first and second polyolefinic facing layers; co-extruding the melts through a flat film die, wherein the first and second polyolefinic facing layers are co-extruded on either side of the base layer; solidifying the co-extruded film by cooling; longitudinally stretching the co-extruded film at a temperature from about 120.degree. to 130.degree. C. in a ratio of from about 5 to 7:1; transversely stretching the co-extruded film at a temperature from about 160.degree. to 170.degree. C. in a ratio of from about 8 to 10:1; and corona-treating one facing layer of the co-extruded film which is metallizable. Each of the melts contains a calcium carbonate neutralizing agent having an absolute particle size of less than about 10 .mu.m, a mean particle size of less than about 0.1 .mu.m, a specific surface area of more than about 40 m.sup.2 /g and a whiteness of more than about 90%, and also a phenolic stabilizer against thermal degradation which has a molecular weight of more than about 1,000 g/mol, and wherein one p…