Patent Application
20090097783
1. Field of the Invention
The present invention relates to a slider zipper which has a high burst strength, allowing the zipper to withstand dropping or shock loading without the zipper opening, while retaining an easy opening capability for the user.
2. Description of the Prior Art
The prior art of high-burst easy-opening of reclosable packages or bags, has become well-developed, particularly in view of commonly assigned U.S. patent application Ser. No. 11/728,477 entitled “High Burst Zipper Assembly for Large Reclosable Packages”; U.S. patent application Ser. No. 11/728,405 entitled “Method of Producing High Burst Zipper Assemblies for Large Reclosable Packages” and application Ser. No. 11/728,413 entitled “Hot-melt Adhesive Systems for Zipper Assemblies on Large Bag Constructions of Various Substrates”, all filed on Mar. 26, 2007. In particularly, these references relate to large reclosable packages or bags which are bottom filled and which have a zipper with high burst resistance which further maintains relative ease in manual opening.
Further improvements are always sought in the art of reclosable packages or bags, particularly in achieving a high burst capability while maintaining relative ease in manual opening in reclosable packages or bags.
It is therefore an object of the present invention to provide a reclosable package or bag, including a reclosable zipper, wherein the zipper maintains a high burst strength
It is therefore a further object of the present invention to provide a reclosable package or bag, including a reclosable zipper, wherein the zipper retains a relative ease in manual opening.
These and other objects are attained by providing a reclosable package, bag or other packaging, including a reclosable zipper. The reclosable zipper includes three distinct flanges in which one face of the middle or interior zipper flange is coated with a peel seal material. The peel seal is activated to seal the interior flange to the exterior flange of the opposing profile so as to render the top of the package or bag closed. This takes advantage of the characteristic of a peel seal having a much higher (as much as ten times) shear separating force than a peel separating force. To this end, a load placed on the package puts the peel seal into a shear mode thereby increasing the burst strength of the package or bag.
The zipper is configured and arranged to be sealed to the inside faces of the package or bag. Therefore, the external surfaces of the two exterior zipper flanges include a coextruded material that is heat activated to adhere the zipper to the substrate. Alternatively, the exterior surfaces of the zipper flanges can be adhered to the substrate with glue.
Typically, the zipper assembly is designed to be “post-applied” by insertion into the package or bag. The zipper assembly would typically be sealed to one interior face of the package or bag at the converter, to allow for subsequent filling at another site. The zipper assembly can be applied to one package or bag surface behind the gussets, which will allow for a full mouth opening, or the zipper can be applied over the gussets, which creates an elliptical opening for the filling operation.
The second face of the package or bag substrate is sealed to the zipper assembly after the filling operation.
However, it is likewise envisioned that this zipper assembly could be applied using other methods, such as, but not limited to, an in-line process using a converter's pouch machine.
Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawings and claims, wherein:
Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that
Package or bag 100 includes first and second co-extensive panels of web or film 102, 104, respectively, which are typically formed of polymeric material, multi-wall paper or similar packaging material. The package or bag 100 may be envisioned to be dimensioned to hold between three and thirty-three pounds of product, but can certainly be provided in a range of other sizes.
First and second panels 102, 104 are joined at the bottom 106 (typically square pre-made) and the sides 108, 110 thereby forming a mouth 112 between the upper edges of the first and second panels 102, 104. Gussets 114, 116 are shown in phantom and are further formed at sides 108, 110, respectively (also see
Zipper 10 is sealed to the interior of the upper edges of the first and second panels 102, 104 thereby making mouth 112, and hence package or bag 100, reclosable.
Zipper 10 is shown in detail in the cross-sectional view of
Second profile 14 includes second interlocking element 40 from which second exterior flange 42 descends. Peel seal 44 is formed between the exterior face 46 of interior flange 22 and the interior face 43 of second exterior flange 42. This is typically done by coating the exterior face 46 of interior flange 22 with peel seal material and activating the peel seal so as join the interior face 43 of second exterior flange 44. As peel seal 44 is typically not resealable after the initial opening by the consumer, this provides a tamper-evident quality.
Additionally, as shown in
The exterior faces of first and second exterior flanges 20, 42 are sealed, glued, or otherwise joined to the interior of respective first and second co-extensive panels 102, 104 of web or film. In the case of heat sealing, the exterior faces of first and second exterior flanges 20, 42 are provided with a material, typically coextruded, that is heat activated to adhere zipper 10 to the first and second co-extensive panels 102, 104.
Packages or bags 100 of this configuration are typically top filled prior to the attachment, or the completion of the attachment of zipper 10 to package or bag 100. Typically, one of the first and second exterior flanges 20, 42 is sealed to the interior of the corresponding first or second co-extensive panel 102, 104 at the converter to allow for filling with product at another site. The selected exterior flange (illustrated as second exterior flange 42 in
The remaining exterior flange is typically sealed to the corresponding panel after the filling process.
In the resulting configuration, a load or force on first and second co-extensive panels 102, 104, such as might be caused by dropping the full package or bag 100, will extend the panels 102, 104 as shown in
Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.
