Abstract:
A method of manufacturing is provided for a reclosable, free standing package adapted to be self-supporting in an upright position when resting on a horizontal support surface. The method includes the steps of providing a bottom panel in the form of a stand-up web having a planar base and a pair of legs depending from opposite sides of the base; inserting the stand-up web between a first film panel and a second film panel; and creating spaced apart bottom edges of the package by sealing a lower end of the first film panel to one of the legs, and a lower end of the second film panel to the other of the legs such that an entire surface of the base lies substantially parallel to a plane containing the bottom edges.

Description:
FILED OF THE INVENTION  
       [0001]     The present invention relates broadly to reclosable packages and methods of forming such packages, and more particularly, pertains to reclosable packages manufactured on form, fill and seal machines wherein the reclosable packages are self-supporting.  
       BACKGROUND OF THE INVENTION  
       [0002]     Form, fill and seal technology is known in the packaging industry as a method to package consumable goods. Consumable goods that are not used completely when the package is initially opened rely on a zipper closure to reclose the package and keep the remaining contents fresh. In some applications, a tamper-evident seal is included on the package to signify whether access has been gained to the zipper closure. Examples of consumable goods that are often packaged in packages with a zipper closure include potting soil, fertilizer, pet food, dog biscuits, and many different foods edible by humans.  
         [0003]     For certain goods, the bottom of the reclosable package is provided with a configuration that will enable the package to stand up and be self-supporting in an upright position when resting on a horizontal supporting surface such as a shelf, cupboard, table or the like. Further developments in providing these types of stand-up packages with improved stability are desirable.  
       SUMMARY OF THE INVENTION  
       [0004]     It is one object of the present invention to provide an improved method of manufacturing a reclosable, stand-up package by inserting a stand-up web in a horizontal form, fill and seal process for making plastic bags.  
         [0005]     It is also an object of the present invention to provide an improved reclosable, stand-up package that has a stronger, sturdier and more stable base capable of supporting the package so that it will not tip over.  
         [0006]     The present invention is directed to a method of manufacturing a reclosable, free standing package adapted to be self-supporting in an upright position when resting on a horizontal support surface. The method includes the steps of providing a bottom panel in the form of a stand-up web having a planar base and a pair of legs depending from opposite ends of the base. The stand-up web is inserted between a first film panel and a second film panel and a lower end of the first film panel is sealed to one of the legs and a lower end of the second film panel to the other of the legs. Thus, an entire surface of the base lies substantially parallel to a plane containing the bottom edges.  
         [0007]     The step of sealing the first and second film panels to the legs includes only horizontal sealing. The method includes the step of creating side seams by providing seals across the first film panel and the second film panel. The method further includes the steps of providing a combined zipper closure and slider device between the first film panel and the second film panel, and sealing a first closure profile of the zipper closure to the first film panel and sealing a second closure profile of the zipper closure to the second film panel. Prior to providing a combined zipper closure and slider device between the first film panel and the second film panel, the continuous film web can be slit to create the first film panel and the second film panel. Alternatively, the web can be folded onto itself to create the first and second film panels. The step of providing a stand-up web includes unwinding and folding of a supply of film. The method further includes the step of providing a tamper-evident header over the slider device to indicate whether access has been gained to the slider device. The method also includes the step of providing a tamper-evident membrane between the first closure profile and the second closure profile. The step of slitting the film web is preceded by the step of passing the film over a V-board. The step of providing a combined zipper closure and slider device between the first film panel and the second film panel includes the step of feeding the combined zipper closure and slider device through a bottom end of the V-board. Alternatively, the step of providing a combined zipper closure and slider device between the first film panel and the second film panel includes a step of feeding the combined zipper closure and slider device in front of the V-board.  
         [0008]     In another aspect of the invention, a reclosable, stand-up package includes first and second side panels, each having a top edge, opposed side edges and a bottom edge. The opposed side edges of the side panels are sealed together. A zipper closure is sealed to the first and second side panels along the top edges thereof. The zipper closure extends from one of the sealed side edges to the other of the sealed side edges. A slider device is operably mounted on the zipper closure for opening and closing the zipper closure. A bottom panel has a planar base and a pair of legs depending from opposite ends thereof. The pair of legs are sealed to the bottom edges of the first and second side panels such that the base is raised a constant distance above the bottom edges. The bottom panel provides a widened configuration enabling the package to be self-supporting in an upright position when the bottom edges are adapted to rest on a horizontal support surface. The legs of the bottom panel are sealed to the bottom edges of the first and second side panels along entire lengths of the bottom edges extending between the opposed sealed side edges. The zipper closure includes a removable internal tamper-evident membrane extending between the first and second side panels. The package also includes a removable tamper-evident header connected to the zipper closure and surrounding the slider device.  
         [0009]     Various other objects, features and advantages of the invention will be made apparent from the following description taken together with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEW OF THE DRAWINGS  
       [0010]     The drawings illustrate the best mode presently contemplated of carrying out the invention.  
         [0011]      FIG. 1  is a perspective view of a flexible, reclosable stand-up package with a tamper-evident header attached thereto;  
         [0012]      FIG. 2  is a schematic, sectional view of a folding step used in forming the flexible, reclosable stand-up package;  
         [0013]      FIG. 3  is a schematic, sectional view of a slitting step used in forming the flexible, reclosable stand-up package;  
         [0014]      FIG. 4  is a schematic, sectional view of the insertion of a combined slider device and zipper closure during the formation of the flexible, reclosable stand-up package;  
         [0015]      FIG. 5  is a schematic, sectional view of the insertion of a stand-up web used in forming the flexible, reclosable stand-up package;  
         [0016]      FIG. 6  is a schematic, sectional view of a filling operation, and the creation of a tamper-proof header used in forming the flexible, reclosable stand-up package;  
         [0017]      FIG. 7  is a schematic, sectional view of a sealing operation for the stand-up web used in forming the flexible, reclosable stand-up package;  
         [0018]      FIG. 8  is a schematic, sectional view of the locating of score lines in the tamper-proof header used in forming the flexible, reclosable stand-up package;  
         [0019]      FIG. 9  is a schematic, sectional view of the removal of the tamper-proof header from the flexible, reclosable stand-up package;  
         [0020]      FIG. 10  is a perspective view of the finished, flexible, reclosable stand-up package with the tamper-proof header removed;  
         [0021]      FIG. 11  is a schematic, perspective view of a horizontal form, fill and seal machine for manufacturing the flexible, reclosable stand-up package; and  
         [0022]      FIG. 12  is a schematic view similar to  FIG. 11  but showing an alternative location for feeding the combined slider device and zipper closure in the form, fill and seal machine. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0023]     The addition of a stand-up web to a flexible package, such as a bag, is advantageous in enabling the package to be self-supporting without tipping over. The process described herein installs a stand-up web to bags manufactured using form, fill and seal machines.  
         [0024]     A flexible, reclosable package or bag  10  having side panels  12 ,  14  and a raised bottom panel  16  is shown in  FIG. 1 . Side panels  12 ,  14  are sealed together at side seams  18 ,  20 , and sealed at lower ends with a pair of bottom edges  22 ,  24  on bottom panel  16 . A zipper closure arrangement having mating profiles to open (unseal and reseal) the bag  10  is shown at  26 . The zipper closure  26  can include a variety of configurations and structures. The zipper closure  26  includes a first mating profile  28  ( FIG. 4 ) and a second mating profile  30  ( FIG. 4 ) that engage and disengage, as appropriate, to open and close the bag  10 . Zipper closure  26  extends from a first edge  32  of the bag  10  to a second edge  34  across a mouth  36 . First and second profiles  28 ,  30  have respective first and second flanges  38 ,  40  depending therefrom which are sealed to inner, upper surfaces of the side panels  12 ,  14  as seen in  FIG. 9 . The ends of the flanges  38 ,  40  include an internal tamper-evident membrane  42  that lies within the interior of bag  10 . In order to gain access to the interior of the bag  10 , the tamper-evident membrane  42  needs to be ruptured. Membrane  42  can be integrally formed with flanges  38 ,  40  when zipper closure  26  is extruded or can be applied after the mating profiles have been formed.  
         [0025]     A slider device  44  is mounted on zipper closure  26  to facilitate opening and closing zipper closure  26 . Slider devices and how they function to open and close zipper closures in general are taught in U.S. Pat. Nos. 5,063,644; 5,301,394 and 5,664,220, each of which is incorporated by reference herein. A notch (not shown) is disposed within zipper closure  26  adjacent to edge  34  in the bag  10 . The notch is designed to provide a “park place” into which slider device  44  settles when zipper closure  26  is sealed and slider device  44  is at the first edge  32 . Such notch decreases any tendency for an incomplete interlock between first mating profile  28  and second mating profile  30 .  
         [0026]      FIG. 1  illustrates an external tamper-proof or tamper-evident header  46  disposed over slider device  44 . By “tamper-evident”, it is meant that it provides an indication to the consumer as to whether the package  10  has been previously opened. In this embodiment, the tamper-proof header  46  covers and forms a complete enclosure around the zipper closure  26  and slider device  44 . Tamper-evident header  46  is formed by sealing the tops of side panels  12 ,  14  over slider device  44  as further depicted in  FIGS. 6, 7  and  8 . In order to access the interior of package  10  and slider device  44  for the first time, the tamper-evident header  46  needs to be removed as shown in  FIG. 10 . Various tamper-evident structures are known throughout the art of resealable packaging and may be used in lieu of tamper-evident header  46 .  
         [0027]     The bag  10  described and shown in  FIG. 1  can be manufactured by a horizontal form, fill and seal machine  48  generally of the type set forth in U.S. Pat. No. 6,293,896 herein incorporated by reference. The bag  10 , whether with or without the tamper-evident membrane  42  and the tamper-evident header  46 , is manufactured, filled and sealed by a single process that includes sequential steps. The zipper closure  26 , slider device  44  and any tamper-evident structure are applied to the bag  10  prior to the bag  10  being filled with items.  
         [0028]     Referring now to  FIG. 11 , the horizontal form, fill and seal machine  48  includes a process line that progresses from right to left such that, the final fill bag  10  is at the left of the Figure. The package or bag  10  is manufactured upside down so that filling takes place through the bottom of the bag  10 .  
         [0029]     The web  50 , which will provide side panels  12 ,  14 , is supplied on a roll. In an alternative embodiment, the web  50  may comprise one or more layers of film. A series of tensioners  52  helps to control tension on the web  50  during the bag making process. From the tensioners  52 , the web  50  progresses to a V-board  54  where the web  50  is folded as depicted in  FIG. 2 . In the first embodiment of the invention, a slitter knife  56  close to the face of V-board  54  slits web  50  into two panels or halves of web  58 ,  60 . Alternatively, as shown in  FIG. 12 , the slitter knife can be eliminated and the web  50  simply folded to create the side panels  58 ,  60 .  
         [0030]     An extended length of zipper closure  26  is provided via spool  62  simultaneously with the feeding of film  50 . The “home” notches discussed above are punched into zipper closure  26  at an interval defined by the bag width by an in-line punch  64  that may be a die, stamp, knife or other such process. Each notch is formed in the profile of zipper closure  26  before the zipper closure  26  is incorporated into the bag  10 . Slider device  44  is provided from a rotating bowl  66  having a delivery conduit  68  which delivers a series of properly-oriented slider devices  44  to an applicator  70 . The applicator  70  combines the zipper closure  26  with slider device  44  so that the slider device  44  is parked in the notch punched in the zipper disclosure  26 . If misaligned on the zipper closure  26  or notch, the slider device  44  can be phased into register with the notch by sliding or moving the slider device  44  along zipper profile by guides or the like, until the slider device  44  is in register with the bag parked position or notch.  
         [0031]     The zipper closure  26  with the slider device  44  is fed through a slot or the like at the base of the V-board  54  in between the two film halves  58 ,  60  of web  50  as represented in  FIG. 4  with profiles  28 ,  30  being separated. With this arrangement, the combined zipper closure  26  and slider device  44  is allowed to travel in a straight line from the point where slider device  44  is applied to zipper closure  26  to a point where the combined zipper closure  26  and slider device  44  are attached to the film halves  58 ,  60 . Preferably, once attached to the film halves  58 ,  60 , a straight line of travel, with no bends or turns, is maintained.  
         [0032]     It is to be noted that because the bag  10  is manufactured upside down (i.e. the top of the bag  10  is at the bottom of the process line), the zipper closure  26  with the slider device  44  is positioned at the bottom of the film halves  58 ,  60  during bag formation.  
         [0033]     After the film halves  58 ,  60  pass between a pair of vertical rolls  71 , a film from a roll  72  is folded at  73  ( FIG. 11 ) to provide a stand-up, three sided web  74 . The stand-up web  74  is positioned and held between the lower portions of the film halves  58 ,  60  as illustrated in  FIG. 5 . The stand-up web  74  includes a planar base  76  and a pair of depending, diverging legs  78 ,  80  of equal length, and serves to define the raised bottom panel  16  of the finished bag  10 . As will be appreciated hereafter, the stand-up web  74  is sized to provide a widened configuration at the bottom of finished bag  10  in order to enable the bag  10  to be self-supporting with a better stability than prior art stand-up packages.  
         [0034]     After the introduction of the stand-web  74 , heated seal bars  82  provide vertical seals on the film and zipper closure combination. These vertical seals will eventually result in side seams  18 ,  20  of package or bag  10  in  FIG. 1 . Side seams  18 ,  20  extend along the entire height of bag  10 . Typically, each seal bar  82  has a pair of bars on opposite sides of the film. Heat may be provided on one or both sides.  
         [0035]     A top seal bar  84 , positioned at the bottom of the process line, seals the zipper closure  26  to the film halves  58 ,  60  and can further be used to provide sealing of the tamper-evident header  46 . The tamper-evident structure  46  provides an indication to the consumer whether bag  10  has been previously opened. In order to gain access to the interior of bag  10 , the tamper-evident header  46  needs to be penetrated. Top seal bar  84  has first sealing surfaces positioned to provide pressure and typically heat to the area where the flanges  38 ,  40  of zipper closure  26  meets the film halves  58 ,  60  to form seals  86 ,  88  ( FIGS. 6-9 ). The top seal bar  84  also has second surfaces positioned to provide pressure and to typically heat an area below slider device  44  in  FIG. 6  and form a seal between film halves  58 ,  60  at a topmost, horizontal seals  90 .  
         [0036]      FIG. 6  represents a sectional view of the bag formation process after the seals  86 ,  88  and  90  have been made, and the bag being formed arrives at a filling station  92  ( FIG. 11 ) downstream of seal bar  84 . At the filling station  92 , items or materials  94  (e.g. cereal, snack food, fertilizer, etc.) to be contained in the resulting package are delivered by hopper  96 . Hopper  96  includes valves, gates and doors, as needed, to deposit an appropriate amount of item  94  into the package from the bottom thereof while the stand-up web  74  is held away from the hopper  96  and the item or material flow.  
         [0037]     A bottom seal bar  98  located at the top of machine  48  is used to heat seal the base  76  and provide seals  100 ,  102  between legs  78 ,  80  of the stand-up web  74  and the bottom edges of the film halves  58 ,  60  as depicted in  FIG. 7 . Seals  100 ,  102  extend across the entire length of the bottom edges from side seam  18  to side seam  20 . As a result, base  76  forms a raised bottom wall for the finished package  10 . It will be understood that the size of the stand-up web  74  and, particularly its width, will dictate the degree of widened configuration at the bottom of the package which will make the bag  10  more stable and prevent tipping over as it sits on a horizontal support surface. In  FIGS. 5-9 , the height of the legs  78 ,  80  is shown exaggerated for clarity only and it should be appreciated that the base  76  usually sits much closer to the surface on which bag  10  is supported, as shown in  FIGS. 1 and 10 . It is to be noted that the entire base  76  will be spaced above a support surface over a constant distance defined by the equal height of the legs  78 ,  80 . In other words, the raised bottom panel  16  lies generally parallel to a plane defined by the bottom edges  22 ,  24 .  
         [0038]     Bottom seal bar  98  may include an adjustable depth perforator for providing perforations  104  ( FIG. 8 ) in the film between the area of the zipper closure/film seams  86 ,  88  and the seam  90  at the top of the film halves  58 ,  60 . These perforations or score lines  104  allow easy removal of the tamper-evident header  46  by the consumer. Preferably, the perforations  104  or other weakened area are positioned close to the area where the zipper flanges  38 ,  40  are sealed to the film halves  58 ,  60 . This is done to minimize the amount of film remaining close to the slider device  44  after the tamper-evident header  46  is removed from bag  10  as illustrated in  FIG. 9 .  
         [0039]     A vertically oriented blade or cutter bar  106  cuts the edges at the side seams  18 ,  20  to provide individual, filled, free standing packages  108 .  
         [0040]      FIG. 12  depicts an alternative form, fill and seal machine  48  identical to that disclosed above except that zipper closure spool  62 , in-line punch  64 , slider bowl  66 , delivery conduit  68  and zipper closure and slider device applicator  70  are located above the process line rather than beneath it. In this design, the combined zipper closure and slider device is fed in front of the V-board  54  for insertion between film halves  58 ,  60 . As shown in  FIG. 12 , the V-board  54  does not include a slitter such that the web  50  maintains its integrity and is folded to create the side panels  58 ,  60 .  
         [0041]     It should now be appreciated that either process machine  48  provides a flexible, reclosable stand-up bag  10  with a removable tamper-evident header  46  as shown in  FIG. 1 , as well as an internal tamper-proof membrane  42  as seen in  FIG. 9 . The insertion of stand-up web  74  enables the bag  10  to have a widened lower configuration with a raised bottom panel  16  so that the bag is self-supporting with enhanced stability. The stand-up web  74  can be made from a stiffer material than film panels  58 ,  60  and could be made from a transparent material that would allow the consumer to view the contents of the bag  10 . In addition, the stand-up web  74  may include a material that has a high amount of metalizing which would give the package even greater stability.  
         [0042]     Having described the presently preferred embodiments, it is to be understood that the invention may be otherwise embodied within the scope of the appended claims.