Heat-sealable shrink film based on polypropylene

US5234733A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

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

Key dates

• Filing date: May 3, 1989
• Grant date: Aug 10, 1993
• Expiry date: May 3, 2009

Classification

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

Abstract

A shrink film which is comprised of a plurality of polyolefinic layers is disclosed. The base layer comprises polypropylene and a hydrogenated hydrocarbon resin admixture, and the top layers on each side of the base layer comprise polyolefinic sealable raw materials. The film possesses a shrinkability of more than 15% in the transverse direction and of less than 6% in the longitudinal direction, both measured at 90.degree. C. Also disclosed is a process for manufacturing the film comprising coextrusion followed by stretching of the film in the longitudinal and transverse directions, whereby stretching in the longitudinal direction is performed such that the double refraction value .DELTA.n of the longitudinally oriented film is not greater than 15.times.10.sup.-3.