Arching zipper and method of manufacture

Abstract

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.

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.