Transparent shrink film based on polypropylene, process for its manufacture, and its use for shrink labels

US5091237A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gunter Schloegl · Kelkheim, DE
• Lothar Bothe · Mainz, DE
• Guenther Crass · Taunusstein, DE
• Ursula Murschall · Nierstein, DE
• Herbert Peiffer · Mainz, DE

Key dates

• Filing date: Jun 26, 1989
• Grant date: Feb 25, 1992
• Expiry date: Jun 26, 2009

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31924
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A shrink film comprising at least one polyolefinic layer comprising polypropylene and a resin admixture is disclosed. The film processes a shrinkability of more than 20%, measured at 90.degree. C., in the transverse direction and of less than 8%, also measured at 90.degree. C., in the longitudinal direction. The film is manufactured by coextrusion followed by stretching in the longitudinal and transverse directions, whereby stretching in the longitudinal direction is performed such that the birefringence value .DELTA.n of the longitudinally oriented film does not exceed the range from 10.times.10.sup.-3 to 13.times.10.sup.-3.