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:
May. 11, 1999
Filed:
Jul. 02, 1997
Edward M Bullard, Rochester, NY (US);
David V Dobreski, Fairport, NY (US);
George N Eichbauer, Conyers, GA (US);
Richard E Leone, Newark, NY (US);
W Mark Dutt, Gurnee, IL (US);
Tenneco Packaging Inc., Evanston, IL (US);
Abstract
A multilayer, thermoplastic stretch wrap film containing at least four polymeric film layers and comprised of a first outer cling layer, a second outer cling layer, at least one inner polymeric layer and at least one core layer. The first and second layers have a cling force to s each other of at least about 140 grams/inch. The stretch wrap film has at least one inner polymeric layer, located between the first and second layers. The inner polymeric layer comprises a low polydispersity polymer. The low polydispersity polymer has a polydispersity of from about 1 to about 4, a melt index (I.sub.2) of from about 0.5 to about 10 g/10 min., and a melt flow ratio (I.sub.20 /I.sub.2) of from about 12 to about 22. The core layer, also located between the outer cling layers, comprises either a random copolymer of propylene and ethylene, a heterophasic copolymer of propylene with domains of ethylene interspersed, a polypropylene homopolymer, or blends thereof. The random ethylene-propylene copolymer has a melt flow ratio of from about 2 to about 15 and an ethylene content in the range of from about 2 to about 6 wt. % of the propylene copolymer. The heterophasic copolymer has a melt flow ratio of about 10 to about 18 and an ethylene content in the range of from about 12 to 30 wt. % of the heterophasic propylene. The polypropylene homopolymer has a melt flow ratio of from about 2 to about 15. The multilayer stretch wrap film has a maximum stretch of at least 340% and a machine direction stress force @ 200% elongation of between about 1400 and about 1900 psi. It is contemplated that additional layers may be added to the present invention.