Flexible bags – Bag closure secured by a releasable or frangible bond
Reissue Patent
1993-07-14
2001-05-08
Pascua, Jes F. (Department: 3727)
Flexible bags
Bag closure secured by a releasable or frangible bond
C206S484000, C206S813000, C428S516000
Reissue Patent
active
RE037171
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to hermetically heat sealable packages which contain a product therein, but which may be readily opened by application of force. Prior art patents teach easy open packages wherein the heat seal is formed by controlling the conditions of forming the seal between two identical seal surfaces, by sealing dissimilar surfaces or by contaminating one or both sealant layers with normally incompatible thermoplastic materials. Examples of these types of packages are disclosed in U.S. Pat. No. 4,782,951 and European patent application No. 0 239 319. These seals do not provide consistent failure mechanism when the package is peeled open.
SUMMARY OF THE INVENTION
The present invention provides an easy open package adapted to be heat sealed to a closed condition to contain and protect a product disposed therein. The package is readily openable by application of force. The package includes a first package wall joined at a portion of its periphery to a second package wall. The first wall comprises a thermoplastic polymeric film construction having an outer layer, an inner sealant layer of polymer and a tie layer disposed between the inner and outer layers. The tie layer is peelably bonded to either the outer layer or the inner layer and permanently bonded to the other layer. The second wall defines a thermoplastic polymeric film construction comprising at least one layer, that layer being a sealant layer of the same polymer as the inner sealant layer of the first wall and disposed adjacent thereto. In another embodiment, an outer layer is provided in the second package wall. In still another embodiment, a tie layer is included in the second package wall, the tie layer disposed between the sealant and outer layers. In all embodiments, when the first wall sealant layer and the second wall sealant layer are heat sealed together, a bond is formed having a greater bond strength than the peelable bond between the tie layer and the layer to which it is peelably bonded. The peel will occur between the two layers having the lower bond strength. This is predetermined by the selection of the compositions of the adjacent layers.
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Bostian David H.
Busche David A.
Curwood Inc.
Lee Mann Smith McWilliams Sweeney & Ohlson
Pascua Jes F.
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