Abstract:
The present disclosure relates to a stay-open configuration or structure at the mouth of a polymeric or similar package or bag, wherein the configuration or structure has sufficient stiffness or tenacity to be able to maintain the mouth of the package or bag in an open position after being placed into this position. The semi-rigid material which implements the stay-open configuration can be incorporated into zipper components, such as, but not limited to, the flanges. The semi-rigid material may further be a separate element which is attached proximate to the zipper. The semi-rigid material typically goes through processes of extrusion and orientation.

Description:
[0001]    This application claims priority under 35 U.S.C. §119(e) of U.S. provisional patent application Ser. No. 61/583,694 filed on Jan. 6, 2012, the contents of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE DISCLOSURE 
       [0002]    1. Field of the Disclosure 
         [0003]    The present disclosure relates to a stay-open configuration or structure at the mouth of a polymeric or similar package or bag, wherein the configuration or structure has sufficient stiffness or tenacity to be able to maintain the mouth of the package or bag in an open position after being placed into this position. 
         [0004]    2. Description of the Prior Art 
         [0005]    In the prior art, reclosures are a common feature on many flexible packages or bags used in the food industry. While the reclosure gives the end user the freedom to use or consume a portion of the contents of the package and store the remainder for future use, simple access to the package contents is not always guaranteed. Because the reclosures on the package are flexible, they do not tend to stay in an open position when opened, thereby typically requiring two-handed operation and raising the possibility that the food item will touch the sides of the package as it is being removed from or placed into the package. For items that are dusty, granular, sticky, greasy, wet, or otherwise unstable or unpleasant to handle, not having a bag or pouch that has the ability to stay open while filling or emptying can be disadvantageous. 
         [0006]    U.S. Pat. No. 7,011,879 entitled “Composite Polymeric Twist Tie” issued on Mar. 14, 2006 to Contreras et al. describes a configuration with a twist tie that is made from plastic materials and which exhibits dead fold/twist characteristics. This reference further describes methods of orienting plastics such that they are able to maintain a dead fold. 
       OBJECTS AND SUMMARY OF THE DISCLOSURE 
       [0007]    It is therefore an object of the present disclosure to provide a configuration or structure for a reclosable package or bag, wherein configuration or structure can maintain the mouth of the package or bag in an open position after being placed into this position. 
         [0008]    This and other objects are attained by providing a stiff polyethylene member proximate to the mouth of a bag. The member can be produced in various cross sections, such as, but not limited to, round or square. The member is produced by stretching through a forming mandrel, with the stretching step having the impact of significantly raising the modulus of the polyethylene material, making it capable of taking a fold or bend and remaining bent or folded. The high modulus polyethylene structure is then placed on to a zipper pouch, typically by sealing it into the pouch behind the zipper. This disclosure therefore incorporates zipper extrusion and orientation. This is intended to preferentially hold the mouth of the pouch open whenever the pouch is placed into an open configuration. 
         [0009]    This typically results in the additional advantages that no metal wire is required, that secondary manufacturing steps are eliminated or reduced, and that a relatively inexpensive method and process is utilized. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Further objects and advantages of the disclosure will become apparent from the following description and from the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a perspective view of a typical pouch, such as a plastic bag, with the stay-open structure of the present disclosure. 
           [0012]      FIG. 2  is a cross-sectional view along plane  2 - 2  of  FIG. 1 . 
           [0013]      FIG. 3  is an alternative cross-sectional view along plane  2 - 2  of  FIG. 1 . 
           [0014]      FIG. 4A  is a schematic of the stretching of the polyethylene material by a forming mandrel. 
           [0015]      FIG. 4B  is a schematic of placing the stretched polyethylene material onto bag wall material for formation into a plastic bag or pouch. 
           [0016]      FIGS. 5A and 5B  show a comparison of a bag or pouch without the stay-open characteristic of the present disclosure versus a bag or pouch with the stay-open characteristic of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  illustrates a typical example of plastic bag or pouch  100  is illustrated. Front and rear walls  102 ,  104  are typically formed from the polymeric material such as, but not limited to, polyethylene. Front and rear walls  102 ,  104 , which are coextensive with each other, are sealed together along bottom seal  106  and side seals  108 ,  110 . Bottom seal  106  may be replaced with a fold if front and rear walls  102 ,  104  are formed from a single piece of bag wall material. A mouth  112  is formed at the top of the bag or pouch  100 . This mouth  112  is made reclosable by zipper  114  which is comprised of first and second profiles  116 ,  118 , a typical example of which is illustrated in the cross-sectional view of  FIG. 2 . As shown in  FIG. 2 , semi-rigid member  10  is typically placed near or behind the first and second profiles  116 ,  118  in order to achieve the stay-open characteristics of the plastic bag or pouch  100 . Alternatively, as will be described with respect to  FIG. 3 , the semi-rigid material may be incorporated into the flanges of zipper  114 , thereby eliminating the need for a separate semi-rigid member  10 . 
         [0018]      FIG. 2  is a typical cross-sectional view along plane  2 - 2  of  FIG. 1 . Although a specific structure of first and second profiles  116 ,  118  of reclosable zipper  114  is illustrated, it should be understood that this disclosure is envisioned to be applicable to a wide range of reclosable zippers. First profile  116  may have first upper and lower flanges  122 ,  124 , extending from a male interlocking element  126  which includes a post  128  terminating in an arrowhead-shaped detent element  130 . Second profile  118  may have second upper and lower flanges  132 ,  134 , extending from a female interlocking element  136  which is formed from first and second extending arms  138 ,  140  terminating in respective first and second detent hooks  142 ,  144  which, in the interlocked position, detent engage the arrowhead-shaped detent element  130  of first profile  116 . First upper and lower flanges  122 ,  124  are sealed or otherwise attached to front wall  102  while second upper and lower flanges  132 ,  134  are sealed or otherwise attached to rear wall  104 . Semi-rigid member  10  is shown sealed between the first profile  116  and the front wall  102  and between the second profile  118  and rear wall  104 . The position of the semi-rigid member  10  is shown directly aligned and outwardly adjacent from the male and female interlocking elements  126 ,  136 . However, variation in this alignment is envisioned to be within the scope of this disclosure. It is envisioned that that the semi-rigid member  10  could be separate from the zipper  114  (see element  10 ′ in phantom on  FIG. 2 ). Furthermore, a wide range of cross-sectional shapes of semi-rigid member  10  is envisioned, such as, but not limited to, square or round. It is also further envisioned that the zipper  114  may be eliminated from some embodiments of the present disclosure. 
         [0019]      FIG. 3  is an alternative cross-sectional view along plane  2 - 2  of  FIG. 1 . In this embodiment, the flanges  122 ,  124 ,  132 ,  134  could incorporate the semi-rigid material, thereby eliminating the semi-rigid member  10 . Again, it is envisioned that a wide range of zipper designs implemented as various embodiments of the present disclosure. 
         [0020]      FIG. 4A  is a simplified schematic of the production of the semi-rigid member  10  of the present disclosure, while  FIG. 4B  is a simplified schematic of the placement of the polyethylene material onto the bag wall material for subsequent formation of a bag or package. Polyethylene material  12  is extruded into a pre-determined profile shape (e.g., round, square or rectangular cross section), using draw ratios, temperatures and similar parameters as would be known to one skilled in the art, and allowed to cool and therefore solidify, and then pulled by opposed driven rollers  201 ,  202  (or a similar device) through an aperture  204  (of decreasing diameter) in forming mandrel  200  which has been heated to a temperature below the melting point of the polyethylene material  12 . The polyethylene material  12  (which typically includes at least a portion of high density polyethylene and which ultimately forms semi-rigid member  10 ) is drawn through the mandrel  200  thereby reducing the cross-sectional area of the profile, resulting in stretching which causes the polymer molecules to align thereby creating a high modulus semi-rigid element  10  to a degree necessary to maintain an open (or closed) position of the bag  100  as shown in  FIG. 5B . The material of semi-rigid member  10  may be coiled onto a reel or similar device for later use and/or joined to a reclosure element. Alternately, as shown in  FIG. 4B , the semi-rigid member  10  is then placed and sealed, glued or otherwise adhered to bag wall material  206  (typically of polymeric material) for subsequent formation into the front and rear walls  102 ,  104  of plastic bag or pouch  100 , a typical example of which is shown in  FIG. 1 . Alternately, as indicated above, the semi-rigid member is then placed and sealed or glued or otherwise attached to the base of the zipper behind the interlocking elements or to the zipper flanges. The semi-rigid material may also be co-extruded at the same time as the zipper material, formed and then attached to the zipper material. 
         [0021]    As a further separate alternative, in order to incorporate the semi-rigid elements into the flanges  122 ,  124 ,  132 ,  134  or other elements of the zipper  114  as illustrated in  FIG. 3 , the following is taken into account with respect to the process of  FIGS. 4A and 4B . It is typically undesirable for the interlocking elements (e.g., male and female interlocking elements  126 ,  136  of  FIG. 2 ) to take a dead fold, therefore these elements could be co-extruded from a material such as low density polyethylene that tends to exhibit less of a dead fold characteristic when oriented and the reclosure elements, such as, but not limited to, the flanges  122 ,  124 ,  132 ,  134  (in place of semi-rigid member  10  in  FIGS. 4A and 4B ), could be extruded from polymers which include at least a portion of high density polyethylene or other material, which does tend to acquire the dead fold characteristic when properly oriented. A further alternative would be to use a process wherein the flanges are extruded separately, then oriented, and then the profile extruded onto the flange. A still further possibility would be to make an oriented flange material and heat seal a pre-made closure element onto it, wherein the closure could be zipper, hook-and-eye (i.e., Velcro®), mushroom shaped interlocking elements, etc. It is noted that the terms low density polyethylene and high density polyethylene are well-defined within the art. 
         [0022]      FIG. 5A  illustrates a prior art bag which does not have the ability to maintain an open configuration whereas  FIG. 5B  illustrates a typical bag  100  of the present disclosure wherein the user can position the mouth in an open position and the increased modulus of the semi-rigid element  10  (not specifically shown in  FIG. 5B ) maintains the mouth  112  in an open position. Likewise, semi-rigid element  10  can be used to maintain the bag  100  in a closed position. 
         [0023]    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.