Abstract:
The method and apparatus relates to providing a slit, perforation, line of weakness or similar structure in a flange of a zipper for a reclosable package or bag, including a high-capacity zipper. The slit, perforation, line of weakness or similar structure provides an opening for filling the reclosable package or bag without the need to separate the zipper profiles from each other. After filling, the opening is sealed and the cosmetic appearance of the reclosable package or bag is maintained.

Description:
BACKGROUND OF THE DISCLOSURE 
       [0001]    This application claims priority under 35 U.S.C. §119(e) of provisional application Ser. No. 61/444,208 filed Feb. 18, 2011, and provisional application Ser. No. 61/515,077 filed on Aug. 4, 2011, the contents of which are hereby incorporated by reference. 
       FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates to reclosable packages or bags that can be filled through the top of the package. The present disclosure further relates to the use of a perforated line or other line of weakness in a large capacity or high burst zipper in order to facilitate a fill-behind-the-zipper operation. 
       DESCRIPTION OF THE PRIOR ART 
       [0003]    In the prior art, reclosable packages or bags have typically been filled two ways. The first is through the open zipper. However, this may not be practical in reclosable packages which use tamper evident structures, such as frangible panels, peel seals or high burst barriers between the zipper profiles and the package interior. Additionally, filling through the zipper may be problematic if a removable shroud over the top of the zipper is desired. A second method of filling through the top of the package is to leave the flange of one of the zipper halves unattached to one wall of the bag and to fill the bag between the zipper flange and the bag wall. However, this may be disadvantageous in that the final zipper-to-bag seal must be made in the location of the filling operation, which may be remote from the location where the bag was originally manufactured. Additionally, making the zipper-to-bag seal can be problematic in that the zipper and bag material are often made from incompatible materials, such as when a polyethylene zipper is mated to a multi-wall paper bag (MWPB) or to a woven polypropylene bag (wPP). In such an instance, the fill time is greatly increased due to required cooling times for hot melt glue systems. In other instances, long dwell times for heat or ultrasonic welding may be required. 
         [0004]    Large reclosable packages and the methods of manufacture thereof are disclosed in commonly assigned U.S. Pat. No. 7,963,007, issued on Jun. 21, 2011, entitled “High Burst Zipper Assembly for Large Reclosable Packages”; U.S. Pat. No. 7,621,105, issued on Nov. 24, 2009 entitled “Method of Producing High Burst Zipper Assemblies for Large Reclosable Packages” and U.S. published application no. 2008/0047228, published on Feb. 28, 2008, entitled “Hot-Melt Adhesive Systems for Zipper Assemblies on Large Bag Constructions of Various Substrates”. As stated above, while these large reclosable packages have been found to be suitable for their intended uses, further improvements may be sought in designing these packages with respect to filling these packages from the top. In particular, these references disclose that a separate strip of polyethylene material may be attached to the bag wall and one half of the zipper is left unconnected to the bag. Product is filled between the polyethylene strip and the zipper and then the zipper and strip are joined together to seal the bag. However, this method requires that an additional strip of polyethylene be supplied along with the zipper, adding cost and complicating bag construction. 
       SUMMARY AND OBJECTS OF THE DISCLOSURE 
       [0005]    It is therefore an object of the present disclosure to allow top filling in large reclosable packages while minimizing or eliminating the disadvantages discussed above. 
         [0006]    This and other objects are attained by a first embodiment of the method and apparatus wherein a flanged zipper is fed into a bag machine, one of the flanges is slit and overlapped, the slit and overlapped zipper is fed to a bag, product is filled through the slit, and the flange portions are moved back to an abutting overlap position and fused together. 
         [0007]    A second embodiment of the method and apparatus substitutes a high-burst zipper and a pre-formed perforated line or other line of weakness for the slit of the first embodiment. This perforation is typically placed immediately below the wishbone configuration of a high burst zipper. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawing, wherein: 
           [0009]      FIG. 1  is a schematic of a step of slitting the flange of a zipper for a reclosable package or bag further to a first embodiment of the disclosure. 
           [0010]      FIG. 2  is a schematic of a step of feeding the slit zipper to a pre-made package or bag further to a first embodiment of the disclosure. 
           [0011]      FIG. 3  is a schematic of a step of filling the bag with product through the slit in the zipper flange further to a first embodiment of the disclosure. 
           [0012]      FIG. 4  is a cross-sectional view of the zipper profile prior to slitting further to a first embodiment of the disclosure. 
           [0013]      FIGS. 5A  is a cross-sectional view of the zipper profile after the steps of slitting, overlapping and sealing the zipper flange after the step of filling in accordance with a first embodiment of the disclosure. 
           [0014]      FIGS. 5B and 5C  are cross-sectional views of an alternative embodiment of the present disclosure. 
           [0015]      FIG. 6  is a perspective view of a zipper configuration with a perforation or similar line of weakness in the flange of a high burst zipper, further to a second embodiment of the disclosure. 
           [0016]      FIG. 7  is a perspective view of a high burst zipper configuration attached to walls of a package or bag, the zipper configuration shown with the perforation or similar line of weakness open for filling of the package or bag with product, further to a second embodiment of the disclosure. 
           [0017]      FIG. 8  is a perspective view of a high burst zipper configuration wherein the opening in the zipper flange has been sealed after the package or bag is filled with product, further to a second embodiment of the disclosure. 
           [0018]      FIG. 9  is a perspective view of the high burst zipper configuration after sealing of the opening in the zipper flange, illustrating the re-creation of the high burst configuration. 
           [0019]      FIG. 10  is a cross-sectional view of a high burst zipper configuration, shown whereby a number of different zipper profiles may be used, further to a second embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  is a diagram of a zipper  10  which includes first profile  12  and second profile  14 . Zipper  10  is typically made from a polymeric thermoplastic material. First profile  12  includes first flange  16  and first interlocking element  18  while second profile  14  includes second flange  20  and second interlocking element  22 . As is known in the prior art, first interlocking element  18  is configured to interlock with second interlocking element  22 . Likewise, as shown in  FIG. 2 , first and second flanges  16 ,  20  are configured to attach to the first and second walls  50 ,  52  of a reclosable package or bag  54 , particularly, but not limited to, a large reclosable package or bag, including a high burst zipper, which may contain as much as fifty pounds of contents or more. 
         [0021]    As shown in  FIG. 1 , slitter  100  cuts a slit  24  in first flange  16  so that first flange  16  includes upper portion  26  above the slit  24  and lower portion  28  below the slit  24 . The slitter  100  may be stationary with the motion of the zipper  10  being fed into a bag machine (not shown) providing the relative movement between the slitter  100  and the zipper  10  and resulting in the linear character of slit  24 . The lower portion  28  is then moved up to form an overlapping region  30  with respect to upper portion  26 . Alternatively, the first flange  16  could be provided with a perforation or other line of weakness wherein the line of weakness is broken in lieu of using a slitter  100 . 
         [0022]    As shown in  FIG. 2 , after the slit  24  and overlap have been formed, the zipper  10  is fed to between first and second walls  50 ,  52  of a reclosable package or bag  54 , which is shown with optional first gusset  56  formed between first and second walls  50 ,  52  (optionally with a similar gusset on the opposite side, obscured from view in  FIG. 2 ). 
         [0023]    First and second flanges  16 ,  20  of zipper  10  are secured to first and second walls of reclosable package or bag  54 , typically by hot melt or other adhesives, or by heat or ultrasonic welding. Alternately, pre-slit, overlapped and end-sealed zipper  10  may straddle the reclosable package or bag  54  and be attached to the outer faces of walls  50 ,  52 . The ends of zipper  10  are fused together and zipper  10  is cut to length thereby achieving the configuration of  FIG. 3 . Alternately, segments of zipper  10  may be fed to the package or bag  10 . As further shown in  FIG. 3 , slit  24  is spread open and the product is inserted therein. The upper and lower portions  26 ,  28  of first flange  16  are then repositioned into abutting partially overlapping position and sealed, fused or otherwise connected or joined together thereby closing slit  24  as shown in  FIGS. 5A  which illustrates hard seal  60  forming the connection between upper and lower portions  26 ,  28  of first flange  16 . As shown by the comparison between  FIGS. 4  (before the formation of slit  24 ) and  5 A (after the formation of slit  24 , the overlapping of the flanges, the filling of the product and the fusing or sealing of upper and lower portions of first flange  16 ), the first flange  16  may initially be supplied longer than second flange  20  so that the first and second flanges  16 ,  20  achieve an equal length after the above steps have been completed. 
         [0024]      FIGS. 5B and 5C  illustrate an alternative method wherein the upper and lower portions  26 ,  28  of first flange  16  are supplied in overlapping position, but are joined by a peelable seal  62  (using peelable material or a tack seal). In these alternate embodiments, the zipper  10  is attached to reclosable package or bag  54  as described above, but the filling is accomplished by peeling apart the peel seal  62  thereby separating upper and lower portions  26 ,  28  of first flange  16  and creating an opening through which product may be filled. After the reclosable package or bag  54  is filled, the upper and lower portions  26 ,  28  of first flange  16  are joined together again by forming a hard seal  64  away from the peelable seal  62 . The positioning of additional sealant  65 , if required, is shown in  FIG. 5B  and the resulting hard seal is formed in the same location as shown in  FIG. 5C . 
         [0025]    While lower portion  28  is shown to the exterior of the upper portion  26  of the first flange  16 , this configuration could be reversed with the lower portion  28  to the interior of upper portion  26 . Additionally, various easy-open or tamper-evident features, as well as a slider, could be incorporated into this design. Likewise, the fill method could use a one-time opening feature, with the reclosure feature removed or eliminated. 
         [0026]    A second embodiment of the disclosure is shown in  FIGS. 6-10 . In this embodiment, a high burst zipper  70  is used, such as is shown in  FIG. 6 . It should be noted that a high burst zipper  70  could be incorporated into any of the disclosed embodiments. The high burst zipper includes first and second profiles  72 ,  74  with respective first and second flanges  76 ,  78  and first and second interlocking elements  81 ,  82 . Additionally, the high-capacity characteristics of the zipper  70  are enhanced by the internal segment  80  which joins first flange  76  to second flange  78 . Segment  80  may be integrally extruded with first flange  76 . As described in the above-identified U.S. Pat. Nos. 7,621,105 and 7,963,007 and U.S. published application no. 2008/0047228, the lower end of internal segment  80  is joined to second flange  78  by a peel seal  83  and the upper end of internal segment  80  is joined, fastened or secured at a joinder point to first flange  76  by a hard seal  84 . Additionally, it is envisioned that the first and second interlocking elements  81 ,  82  can be implemented with a broad range of designs or configurations. A perforation  86  or other line of weakness is provided in first flange  76  immediately below the hard seal  84 . Additionally, as shown in  FIG. 10 , a first hard seal coextrusion  88  is provided on internal segment  80  immediately below hard seal  84  and a second hard seal coextrusion  90  is provided on the interior of first flange  76  immediately below hard seal  84 , so that first and second hard seal coextrusions  88 ,  90  are facing each other. 
         [0027]    With this second embodiment, perforation or other line of weakness  86  (which may include an opening which is temporarily closed by a fine peel seal) is opened as shown in  FIG. 7 , typically by suction cups, a separating finger or similar apparatus, so as to create a filling port for the previously constructed package or bag  92  (similar to reclosable package or bag  54  of the first embodiment described above). After filling, as shown in  FIGS. 8 and 9 , seal  94  is formed in first flange  76  by the sealing together of first and second hard seal coextrusions  88 ,  90 . This sealing is typically performed by a drag sealer (not shown) and provides or restores integrity to the zipper  70 , thereby typically providing a zipper which is nearly cosmetically identical to other high burst zippers. 
         [0028]    The typical advantages of the second embodiment of this disclosure include that the zipper can be spooled similarly to current zippers, filling can be performed without opening the interlocking profiles of the zipper, the high burst strength of the zipper is not affected, and many types of interlocking elements can be used. 
         [0029]    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.