ARCHING ZIPPER AND METHOD OF MANUFACTURE
Zippers are provided for reclosable packages or bags. By selectively co-extruding a first portion of the zipper with a shrinkable or expandable material, and simultaneously co-extruding a second portion of the zipper with a dimensionally stable thermoplastic or similar material, followed by a step of activating the shrinkage or expansion of the shrinkable material, several different shapes of zipper can be achieved. For instance, by co-extruding the shrinkable material to a lower portion of the zipper or co-extruding the expandable material to an upper portion of the zipper, an upwardly arching or convex shape can be achieved. Similarly, by co-extruding the shrinkable material to an upper portion of the zipper or co-extruding the expandable material to a lower portion of the zipper, a downwardly arching or concave shape can be achieved. Similarly, by co-extruding the shrinkable material to inner portions of the zipper or the expandable material to outer portions of the zipper, a self-opening characteristic may be added to the zipper. Additionally, zippers may be placed at inclined positions in a complementary head-to-head configuration in order to eliminate or reduce waste of packaging material during manufacture.
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1. Field of the Invention
The present invention pertains to an arched or curved zipper for a reclosable package or bag and the method of manufacture thereof. More specifically, the present invention relates to the use of a co-extruded layer of shrinkable or expandable material in the manufacturing of the zipper to induce the arching or curvature of the zipper. Alternative embodiments include placing the zipper at an inclined orientation on the package.
2. Description of the Prior Art
In the prior art, it is well known to use a zipper to selectively open and close a reclosable package or bag. However, the creation of shaped zipper to conform to different package styles has been difficult to achieve while maintaining a high speed manufacturing rate using standard package manufacturing equipment. Additionally, it has been difficult to find satisfactory ways to create a zipper having a self-opening characteristic. Similarly, the placement of zippers at an inclined orientation while avoiding waste of materials has been problematic.
The manufacture of successive head-to-head reclosable packages, with heads cut in the transverse machine direction, is disclosed in U.S. Pat. No. 7,490,451 entitled “Method and Apparatus for Making Block Bottom Pillow Top Bags” issued on Feb. 17, 2009 to Matthews and U.S. Pat. No. 6,428,642 entitled “Transverse Directional Zipper with a Double Seal Flange Profile Configuration” issued on Aug. 6, 2002 to Matthews and Plourde.
OBJECTS AND SUMMARY OF THE INVENTIONIt is therefore an object of the present invention to provide shaped zippers for a reclosable package or bag, and a method for the manufacture thereof which maintains a high manufacturing rate using standard package manufacturing equipment, possibly with some modification.
It is therefore a further object of the present invention to provide shaped zippers for a reclosable package or bag, wherein the shaped zipper may possibly include a self-opening characteristic.
It is therefore a still further object of the present invention to provide for the placement of zippers at inclined orientations on the package while avoiding or minimizing waste of packaging film.
These and other objects are achieved by, during the manufacture of the zipper, co-extruding a layer of shrinkable material (or, alternatively, expandable material) in various places of the zipper in order to manipulate the curvature or shape of the zipper. This shrinkable or expandable material may be placed so that zipper has a curvature within the plane of the walls of the package or bag. Alternatively, the shrinkable material may be placed on opposite sides of the inner surfaces of the flanges (or an expandable material may be placed on opposite sides of the outer surfaces of the flanges) in order to make the profiles of the open zipper flex away from each other thereby creating a self-opening characteristic.
With respect to the placement of zippers at inclined orientations on the package, waste is avoided by manufacturing with a head-to-head configuration.
Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:
Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the several views, one sees that
Front and rear walls 102, 104 are typically joined, sealed or folded to form the bottom 106 and the side edges 108, 110, forming an upper curved mouth 112. Curved mouth 112 is selectively opened and closed by zipper 10 which is curved to accommodate the shape of the curved mouth. Zipper 10 includes first and second profiles 12, 14 which are likewise curved and sealed to respective front and rear walls 102, 104 along upper curved mouth 112. As shown in more detail in
First and second profiles 12, 14 are formed by extrusion. By selectively co-extruding both the base thermoplastic polymer along with a shrinkable material, the curvature in first and second profiles 12, 14 may be formed. A typical example of the shrinkable material would be polyolefin-based shrink-wrap material which is a thermoplastic polymer which is shrunken by exposure to heat. For example, as shown in
An alternative way of achieving shrinkage in a film is to stretch the film while it is cool, and subsequently to heat the film thereby allowing the molecules to relax thereby causing the film to return to its original length. For example, a flange material could be stretched, then a zipper profile attached to the flange. When the flange material is subsequently heated, the film will tend to shrink to its original length, resulting in an arched zipper configuration.
Similarly, as shown in
Alternately, an expandable foam or other expandable polymer can be co-extruded in the locations marked by x's in
Similarly, as shown in
In
Similarly in
In all of the illustrated embodiments, it is envisioned that the activation of shrinkage can be done at various stage of the manufacture of the package or bag 100, such as prior to, during, or after the application of the zipper 10 to the package or bag 100.
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.
Claims
1. A reclosable package including front and rear package walls with an opening forming a mouth, the mouth having a curved shaped in the plane of the front and rear package walls and being reclosable by a zipper, wherein the zipper includes first and second profiles with a shape which conforms to the curved shape of the mouth.
2. The reclosable package of claim 1 wherein the mouth extends substantially a width of the reclosable package.
3. The reclosable package of claim 1 wherein the mouth extends less than a width of the reclosable package.
4. The reclosable package of claim 1 wherein the curved shape is upwardly arching.
5. The reclosable package of claim 1 wherein the curved shape is downwardly arching.
6. The reclosable package of claim 1 wherein the curved shape includes a first portion which is upwardly arching and a second portion which is downwardly arching.
7. The reclosable package of claim 1 further including a slider to selectively interlock or separate the first and second interlocking elements.
8. The reclosable package of claim 1 wherein the first and second interlocking elements flex away from each other when the first and second interlocking elements are not interlocked with each other.
9. A zipper for a reclosable package or bag, including:
- a first zipper profile and a second zipper profile; and
- wherein a first portion of at least one of the first and second zipper profiles is formed with a shrinkable material and wherein a second portion of at least one of the first and second zipper profiles is formed with a dimensionally stable material, whereby shrinkage of the shrinkable material causes the zipper to change shape.
10. The zipper of claim 9 wherein the first zipper profile includes a first interlocking element and a first flange and wherein the second zipper profile includes a second interlocking element and a second flange.
11. The zipper of claim 10 wherein the first portion of at least one of the first and second zipper profiles includes the first and second flanges.
12. The zipper of claim 11 wherein the dimensionally stable material is a thermoplastic polymer.
13. The zipper of claim 11 wherein the shrinkable material is polyolefin-based material which shrinks in response to heat.
14. The zipper of claim 9 further including a slider to selectively interlock or separate the first and second interlocking elements.
15. A zipper for a reclosable package or bag, including:
- a first zipper profile and a second zipper profile; and
- wherein a first portion of at least one of the first and second zipper profiles is formed with an expandable material and wherein a second portion of at least one of the first and second zipper profiles is formed with a dimensionally stable material, whereby expansion of the expandable material causes the zipper to change shape.
16. The zipper of claim 15 wherein the first zipper profile includes a first interlocking element and a first flange and wherein the second zipper profile includes a second interlocking element and a second flange.
17. The zipper of claim 16 wherein the first portion of at least one of the first and second zipper profiles includes the first and second flanges.
18. The zipper of claim 17 wherein the dimensionally stable material is a thermoplastic polymer.
19. The zipper of claim 15 wherein the expandable material is a foam which expands in response to heat.
20. The zipper of claim 15 further including a slider to selectively interlock or separate the first and second interlocking elements.
Type: Application
Filed: May 4, 2009
Publication Date: Nov 4, 2010
Applicant:
Inventors: Charles Greco (Bardonia, NY), Eric Plourde (Frankfort, IL), Rusty Koenigkramer (Nanuet, NY)
Application Number: 12/435,158
International Classification: B65D 33/16 (20060101);