JOHNSON, Joel, L. (3600 West Lake Avenue, Glenview, IL, 60026, US)
CLAIMS
What is Claimed is:
1. A zipper for a reclosable bag, including: a first profile including a first interlocking element and a first flange, a second profile including a second interlocking element and a second flange, and said first flange and said second flange including an oxygen scavenging polymer.
2. The zipper of Claim 1 further including a slider which joins said first and second interlocking elements to each other when moved in a first direction and which separates said first and second interlocking elements from each other when moved in a second direction.
3. The zipper of Claim 1 wherein said flanges include a plurality of co-extruded layers, wherein at least one of said co-extruded layers includes an oxygen scavenging polymer.
4. The zipper of Claim 3 wherein said co-extruded layer including an oxygen scavenging polymer is an outer layer in relation to other layers.
5. The zipper of Claim 1 wherein said first and second flanges are comprised of a blend of a plurality of polymers, at least one of said polymers being an oxygen scavenging polymer.
6. The zipper of Claim 1 wherein said oxygen scavenging polymer is activated by ultra-violet light prior to installation on a reclosable bag.
7. A zipper for a reclosable bag, including: a first profile including a first interlocking element and a first flange, a second profile including a second interlocking element and a second flange, and a strip, including an oxygen scavenging polymer, extending from at least one of said first and second flanges.
8. The zipper of Claim 7 further including a slider which joins said first and second interlocking elements to each other when moved in a first direction and which separates said first and second interlocking elements from each other when moved in a second direction.
9. The zipper of Claim 7 wherein said oxygen scavenging polymer is activated by ultra-violet light prior to installation on a reclosable bag.
10. A zipper for a reclosable bag, including: a first profile including a first interlocking element and a first flange, a second profile including a second interlocking element and a second flange, and a strip, including an oxygen scavenging polymer, attached to one of said first and second interlocking elements and engaged between said first and second interlocking elements.
11. The zipper of Claim 10 further including a slider which joins said first and second interlocking elements to each other when moved in a first direction and which separates said first and second interlocking elements from each other when moved in a second direction.
12. The zipper of Claim 10 wherein said oxygen scavenging polymer is activated by ultra-violet light prior to installation on a reclosable bag. |
SLIDER ZIPPER ASSEMBLY WITH OXYGEN SCA VENGPJG PROPERTIES
BACKGROUND QF THE INVENTION
Field of the Invention
The present invention relates to a slider zipper assembly which is formed by using oxygen scavenging polymers (OSPs) in the extrusion process. The oxygen scavenging polymer can be a co-extruded layer or can be blended with the other resins to be extruded.
Description of the Prior Art
It is well-established that food spoilage can be tied, at least in part, to oxidation.
Therefore, it is advantageous, when packaging food or even when reclosing a bag containing food, to remove or reduce the oxygen to which the food is exposed.
Moreover, particularly with meats and cheese, the removal of trace amounts of oxygen can provide additional shelf life at the point of purchase.
U.S. Patent No. 5,766,706 entitled "Gas Scavenging Arrangement" issued on June 16, 1998 to Custer et al. and U.S. Patent No. 5,954,433 entitled "Reclosable Bag with Improved Opening Feature" have used oxygen scavenging polymers in association with press-to-close zippers. While press-to-close zippers are well-developed and are satisfactory for their intended purposes, these zippers sometimes do not engage as securely as is desired for some applications.
Moreover, as oxygen scavenging polymers are relatively expensive, it is advantageous to use as small of a quantity of OSPs as possible in the manufacture of reclosable bags.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide zippers for reclosable bags, using materials which reduce the oxygen content in the reclosable bag, while maintaining a low cost of manufacture, particularly by minimizing the amount of oxygen scavenging polymers required.
It is therefore a further object of the present invention to provide zippers for reclosable bags with an increased security of engagement, for increasing strength in holding the contents of the reclosable bag.
These and other objects are attained by providing a slider-operated zipper wherein the profiles are formed with oxygen scavenging polymers in the extruding process. The oxygen scavenging polymer can be a co-extruded layer or can be blended with the other resins to be extruded.
Additionally, the process includes activating the oxygen scavenging polymers at the point of packaging by passing the profile under an ultra-violet light source, effectively starting the scavenging process as the zipper is sealed to the packaging web.
This process can be applied to form fill seal apparatus of all kinds which relate to zippered reclosable packages.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawings, wherein:
Figure 1 is a perspective view of a typical embodiment of the zipper of the present invention.
Figure 2 is a perspective view of a typical embodiment of a reclosable bag, including the zipper of the of the present invention.
Figure 3 is a cross-sectional view of a zipper of the present invention along plane 3-3 of Figure 1 , including flanges made from co-extruded layers, with the outer layer being made from oxygen scavenging resins.
Figure 4 is a cross-sectional view of a zipper of the present invention along plane 3-3 of Figure 1, including flanges made from blended polymers, including at least one oxygen scavenging polymer.
Figure 5 is a schematic of the feeding of the zipper of the present invention to a form fill seal apparatus, further showing the passing of the zipper by an ultra-violet light source to activate the oxygen scavenging properties.
Figure 6 is a cross-sectional view of a first alternative embodiment which includes a strip of oxygen scavenging polymer attached to the flange.
Figure 7 is a cross-sectional view of a second alternative embodiment which includes a strip of oxygen scavenging polymer attached to one profile and caught between the interlocking elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in detail wherein like numerals refer to like elements throughout the several views, one sees that Figure l is a perspective view of a typical zipper 10 of the present invention. Likewise, Figure 2 is a perspective view of a reclosable bag 100, formed from sheets of polymer web, which incorporates the zipper 10 of the present invention.
Zipper 10 includes first and second profiles 12, 14 with first and second interlocking elements 16, 18 and respective first and second flanges 20, 22. Zipper 10
may include optional slider 24 which joins interlocking elements 16, 18 to each other when moved in a first direction and which separates interlocking elements 16, 18 when moved in a second direction. The operation of optional slider 24 is well known in the prior art.
In the illustrated embodiment, first flange 20 includes major portion 30 which extends from first interlocking element 16 to tip 32 and further includes minor portion 34 which extends from tip 32 toward second flange 22, leaving gap 36 therebetween.
This zipper embodiment is intended to be illustrative only. The present invention can be practiced with many different zipper embodiments.
In Figure 3, first and second flanges 20, 22 are illustrated as including an inner layer 50 and an outer layer 52. These layers are co-extruded with outer layer 52 including the oxygen scavenging polymer. Inner layer 50 includes any typical polymer which one skilled in the art would recognize as useful after review of the present disclosure.
In Figure 4, first and second flanges 20, 22 are illustrated as including a single layer with a blend of resins, including at least one oxygen scavenging polymer.
In Figure 5, a spool 200 of zipper 10 is provided. Zipper 10 is passed by ultraviolet light 300 to activate the oxygen scavenging polymer immediately prior to use by the form fill and seal apparatus 400 which uses zipper 10 to manufacture a reclosable bag 100, such as is used in the food industry and shown in Figure 2. Such a configuration reduces the levels of residual oxygen in the reclosable bag 100.
Figure 6 is a cross-sectional view of a first alternative embodiment of zipper 10 which includes strip 60 of oxygen scavenging polymer attached to second flange 22 and extending to the contents of the reclosable bag.
Figure 7 is a cross-sectional view of a second alternative embodiment which includes a strip 62 of oxygen scavenging polymer attached to first profile 12 and engaged between the interlocking elements 16, 18.
The embodiments of Figures 6 and 7 are activated and installed in the same manner as described above.
Such a configuration can be used with form fill seal apparatus of all kinds which employ zippers in the manufacture of reclosable bags or packages, but is particularly useful to form fill seal apparatus which package cheese, meats and similar products in reclosable packages.
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.