The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 1992
Filed:
Aug. 29, 1990
Lothar Bothe, Mainz-Gonsenheim, DE;
Gunter Schloegl, Kelkheim, DE;
Guenther Crass, Taunusstein, DE;
Thomas Wilhelm, Taunusstein, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
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 polyolefinic facing layer contains an anti-blocking agent.