Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1998-12-31
2001-06-19
Thibodeau, Paul (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S412000, C428S421000, C428S475800, C428S476300, C428S483000, C428S516000, C428S518000, C428S520000, C428S511000, C428S910000, C428S035200
Reexamination Certificate
active
06248442
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer film which is heat sealable over a broad temperature range. It is desirable to have a broad sealing temperature range to increase the production of packaging machines. The present invention also relates to a multilayer film which provides easy opening and hermetic seals to packages.
Packaging technology has over the years required the development of many disciplines. Currently packaging technologists integrate elements of engineering, chemistry, food science, metallurgy, and other technologies in order to provide the consumer fresh, healthy dry or liquid. food product. In those cases where packages are prepared from multilayer film, it is desirable to be able to provide a hermetic seal, i.e., a seal which does not permit passage of gas, such as air.
Oriented polypropylene films with thin sealable surface layers of ethylene-propylene copolymers or ethylene-propylene-butene-1 terpolymers have been used in packaging operations. However, these films have not yielded hermetic seals on bags made with the films on packaging machines operated at standard conditions. Hermetic seals are required when leak free packaging is important.
Additionally it is also desirable to provide seals which can be readily opened by the consumer without creating a ‘z-direction’ tear. A z-direction tear is one which cause the disruption of the integrity of the multilayer film when the film is pulled apart at the seal. A z-direction tear is one which does not simply separate at the line at which the seal is formed. Instead, the separation extends to layers of the film when ripped along the layers thereof and not simply delaminated one from another. As a result of z-direction tears, it is difficult to reclose such packages to maintain freshness of the contents. When z-direction tears can be eliminated, packages are easily refolded and sealed by a mechanical means such as a clip
Accordingly it is the object of the present invention to provide a film which yields hermetic seals over a broad temperature range and provides easy opening on bags.
It is a further object of the present invention to provide easy opening with directional tear.
It is still a further object to provide re-sealable packaging with a zipper attachment.
SUMMARY OF THE INVENTION
In accordance with the present invention a multilayer film is provided which is hermetically sealable over a broad temperature range. The film comprises a core layer comprising linear low density polyethylene (LLDPE) and at least one skin layer having a melting point of at least 10° C. below the core layer melting point.
REFERENCES:
patent: 5007143 (1991-04-01), Herrington
patent: 5020194 (1991-06-01), Herrington et al.
patent: 5055338 (1991-10-01), Sheth et al.
patent: 5152613 (1992-10-01), Herrington, Jr.
patent: 5241030 (1993-08-01), Barry et al.
patent: 5278272 (1994-01-01), Lai et al.
patent: 5530065 (1996-06-01), Farley et al.
patent: 5582923 (1996-12-01), Kale et al.
patent: 5604043 (1997-02-01), Ahlgren
patent: 5814399 (1998-09-01), Eichbauer
patent: 5874139 (1999-02-01), Bosiers et al.
patent: 5885707 (1999-03-01), Kaschel et al.
patent: 5919535 (1999-07-01), Dombreski et al.
patent: 5972444 (1999-10-01), Patel et al.
patent: 0 508 165 (1997-06-01), None
patent: 97/22470 (1997-06-01), None
Brant and Fiscus, “Film Property Enhancements by Orienting Metallocene LLDPE” Exxon Chemical Company, Seventh International Business Forum on Speciality Polyolefins (1997).
Kong Dan-Cheng
Mount, III Eldridge M.
Su Tien-Kuei
Mobil Oil Corporation
Santini Dennis P.
Simmons T. Dean
Tarazano D. Lawrence
Thibodeau Paul
LandOfFree
Easy opening hermetically sealed film does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Easy opening hermetically sealed film, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Easy opening hermetically sealed film will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2524124