Patent Publication Number: US-2005135710-A1

Title: Top filled reclosable package and method for forming and filling the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is a Divisional of application Ser. No. 10/742,000, filed on Dec. 19, 2003. 
    
    
     FIELD OF THE INVENTION  
      The present invention generally relates to reclosable packages having a zipper closure mechanism and a slider device for facilitating opening and closing of the zipper closure mechanism. More specifically, the invention relates to a method of filling the reclosable package with a product and closing the reclosable package after the package has been filled.  
     BACKGROUND OF THE INVENTION  
      Flexible packages, and particularly resealable and reclosable packages, are frequently used for packaging consumable products. Products that are not completely used when the package is initially opened rely upon a zipper closure to reclose the package and keep the remaining contents fresh. Examples of consumable products that are often provided in reclosable packages with a zipper closure include potting soil, fertilizer, pet food, dog biscuits, vegetables, cereal and many different types of food, such as cheese, edible by humans.  
      Often, the opening and closing of the zipper closure is facilitated by a slider device that is mounted on the zipper closure. The slider device is constructed to pry apart the interlocking zipper closure members when the slider device is moved in a first direction and to engage the interlocking zipper closure members when the slider device is moved in a second, opposite direction. For some applications, a tamper-evident structure is desired to indicate whether access has been gained to the zipper closure.  
      As discussed above, a typical reclosable package includes a pair of opposing side panels joined to each other along a pair of side seals and a bottom wall that extends between the side panels to define a three-sided, open package interior. The reclosable zipper closure extends along an open mouth of the package opposite the bottom wall. The zipper closure includes a first profile member and a second profile member that are adapted to resealably interlock with each other.  
      If reclosable packages are to be prepackaged with a product and sold in the stores, the packages are typically prepared on a horizontal or vertical form, fill and seal machine. In this type of machine, the reclosable package is first formed into the shape of a pouch having a fill opening at either the top or the bottom. If the fill opening is disposed at the bottom of the package, the zipper closure is attached between the side panels and the top of the package is sealed prior to filling the product into the package.  
      If the package is designed to be filled from the top, the bottom is initially sealed prior to filling of the product. Next, the package is filled with product through a fill opening near the mouth of the package.  
      One method of top filling a package with product is to fill the product through the zipper closure when the first and second profile elements of the zipper closure are in an unmated condition. This type of filling is typically referred to as the “fill through the zipper” method. Once the product has been placed into the package interior, the zipper closure is either mated or left unmated and the top edges of the package are sealed. This type of filling arrangement includes several inherent disadvantages, such as the requirement that the zipper closure must be mated after filling.  
      Alternatively, U.S. Pat. No. 6,071,011 teaches a method of attaching the zipper closure to only one of the side panels prior to the product being inserted into the package interior. The package is then filled with product through a fill opening between the zipper closure and the opposite side panel to which the zipper closure is not yet attached. After the package interior has been filled with product, the zipper closure is sealed to the opposite side panel and the top of the package sealed. The method taught by the &#39;011 patent provides the advantage of allowing the zipper closure to remain in the mated condition during package filling. Improvements to this type of method of filling are desired.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to a flexible, reclosable package that has a zipper closure extending across the mouth of the reclosable package. The zipper closure preferably includes a slider device that can be moved along the zipper closure to engage and disengage a pair of profile members.  
      In accordance with the method of the present invention, a continuous web of plastic material is provided and folded to define opposing first and second side panels. The side panels are preferably joined by a bottom wall such that the side panels and bottom wall define an interior for the reclosable package.  
      A continuous supply of zipper closure is provided between the first and second opposing sidewalls. The zipper closure is formed from a first profile member and a second profile member that are adapted to releasably interlock with each other. Both the first profile member and the second profile member include a dependent attachment flange that provides a point of attachment between each of the profile members and one of the opposing side panels. In the preferred embodiment of the invention, the zipper closure is supplied as a continuous length having the profile members in a mated condition.  
      Once the zipper closure is supplied between the side panels, a pair of side seals are created to seal the first and second side panels to each other. The side seals ultimately define the side edges of the reclosable package. During the formation of the side seals, the continuous length of the zipper closure is sealed between the pair of side panels and severed from the continuous length such that the zipper closure extends across the mouth of the package. After being attached to the side panels along the side seals, the zipper is secured to the side panels only along the side seals. Thus, the remaining portion of the zipper closure between the two secured ends is freely movable across the open interior of the reclosable package.  
      Once the side seals have been created between the first and second opposing side panels to define the open interior of the reclosable package, a product can be inserted into the open interior of the package. Specifically, the product can be inserted into the open interior by allowing the product to pass between the zipper closure and one of the side panels. Since the zipper closure is freely movable across the open interior of the reclosable package, the product can be inserted into the package either between the zipper closure and the first side panel or between the zipper closure and the second side panel. In the preferred embodiment of the invention, the zipper closure is moved away from a centerline of the reclosable package by either a mechanical member or other non-mechanical means, such as the application of pressurized air.  
      Once the zipper closure has been moved away from the centerline of the product package, product is allowed to flow past the zipper closure and into the open interior.  
      After the desired amount of product has been inserted into the open interior, a pair of sealing bars are brought into contact with the first and second side panels at locations generally aligned with the attachment flanges formed on the first and second profile members. The sealing bars are preferably heated and create a seal between the respective attachment flanges and the first and second opposing side panels. The attachment flanges are sealed to the side panels along the entire width of the product package.  
      In the first embodiment of the invention, each of the attachment flanges includes a thickened attachment area to prevent the attachment flanges from sealing to each other during application of the attachment flanges to the side panel. Alternatively, each of the attachment flanges can include a heat resistant layer to prevent the attachment flanges from becoming sealed to each other during this process.  
      Once the product has been loaded into the package and the zipper closure is attached to both of the first and second opposing side panels, the side panels are sealed to each other above the zipper closure. In an alternate embodiment of the invention, a peel-seal is also created between the pair of side panels beneath the zipper closure.  
      In yet another alternate embodiment of the invention, a membrane is included between the pair of attachment flanges such that the membrane extends across the open interior of the product package prior to opening. The membrane includes a line of weakness such that during initial product opening, the membrane separates to provide access to the package interior. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1A  is a schematic front plan view of a reclosable package having a zipper closure and slider device prior to filling with a product;  
       FIG. 1B  is an enlarged view of a portion of the reclosable package of  FIG. 1A ;  
       FIG. 2A  is a section view taken along line  2 A- 2 A of  FIG. 1A  illustrating the zipper closure extending across the mouth of the package prior to product filling;  
       FIG. 2B  is a magnified view illustrating the zipper closure used in the preferred embodiment of the invention;  
       FIG. 3  is a section view taken along line  3 - 3  of  FIG. 1A  illustrating the zipper closure prior to insertion of the product into the package;  
       FIG. 4  is a section view illustrating the insertion of product between the zipper closure and one of the package side panels;  
       FIG. 5  is a section view illustrating the attachment of the zipper closure to the package side panels;  
       FIG. 6  is a schematic front plan view of the reclosable package after being filled with product;  
       FIG. 7  is a section view taken along line  7 - 7  of  FIG. 6   
       FIG. 8  is an enlarged, partial section view illustrating a second embodiment of the reclosable package; and  
       FIG. 9  is an enlarged section view showing a third embodiment of the reclosable package. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      Referring now to the drawings,  FIGS. 1A and 3  depict a reclosable package  10  of the present invention prior to filling with a product. The reclosable package  10  includes a pair of opposed side panels  12 ,  14  that are joined to each other by a bottom wall  16 . In the embodiment of the invention illustrated in  FIG. 3 , the reclosable package  10  includes a gusseted bottom wall  16  that allows the size of the open package interior  18  to increase as product is filled into the package  10 . As can be understood in  FIG. 3 , the reclosable package  10  is formed from a continuous web of plastic material that defines the side panels  12 ,  14  as well as the bottom wall  16 . However, it should be understood that the reclosable package  10  could be formed from individual sheets of plastic material that define the side panels  12 ,  14  and that the bottom wall  16  could be replaced by a thermal formed bottom seal formed by the application of heat and pressure.  
      Referring now to  FIG. 1A , the reclosable package  10  is defined by a pair of spaced side seals  20 ,  22  that extend along the entire height of the package from the top end  24  to the bottom end  26 . The side seals  20 ,  22  are typically formed with a seal bar through the application of both heat and pressure between the pair of side panels  12  and  14 .  
      Although only a single reclosable package  10  is shown in  FIG. 1A , the reclosable package  10  is formed in a continuous process from a continuous web of plastic material that is folded to create the pair of side panels  12 ,  14  and the bottom wall  16 , as best shown in  FIG. 3 . Referring back to  FIG. 1A , the side seals  20 ,  22  separate the individual reclosable package  10  from a continuous chain of reclosable packages. The continuous chain of reclosable packages are formed in accordance with the method and apparatus shown in U.S. Pat. No. 6,412,254, the disclosure of which is incorporated herein by reference. As can be understood, each of the reclosable packages  10  are individually formed and later filled with product in an in-line form, fill and seal process. Alternatively, each of the reclosable packages  10  can be formed and provided to a remote location for filling and sealing at a later time.  
      Referring now to  FIG. 3 , the reclosable package  10  defines an open mouth  28  at the top end  24  of the package  10 . The open mouth  28  allows product to be inserted into the reclosable package  10  in a manner to be described in greater detail below.  
      Referring now to  FIGS. 1B and 2A , the reclosable package  10  includes a zipper closure  30  positioned near the top end  24  of the reclosable package. The zipper closure  30 , as best shown in  FIG. 2A , extends across the open interior  18  of the package  10 . The zipper closure includes a first profile element  32  and a second profile element  34 . Prior to filling with product, the zipper closure  30  extends across the open interior  18  between the pair of spaced side seals  20 ,  22  and is positioned near the top end  24  of the package  10 . The zipper closure  30  can be one of a variety of closure mechanisms while operating within the scope of the present invention. Typically, the first and second profile members  32 ,  34  are manufactured separately from each other, although in some embodiments, the first and second profile members  32 ,  34  can be manufactured as a single piece and then slit or otherwise separated prior to incorporation into the reclosable package.  
      Referring now to  FIG. 2B , the preferred zipper closure  30  is shown. As illustrated, the zipper closure  30  includes the first profile element  32  and the second profile element  34 . The first profile element  32  includes an attachment flange  36 , a base strip  38 , a first closure post  40 , a pair of guide posts  42 ,  44  and an upper flange  46 . As illustrated, the closure post  40  and the pair of guide posts  42 ,  44  extend laterally from the base strip  38  while the attachment flange  36  depends or extends downwardly from the guide post  44 . Likewise, the second profile element  34  includes a base strip  48 , a second closure post  50  and a guide post  52 . Both the closure posts  50  and the guide post  52  extend laterally from the base strip  48 . An attachment flange  54  is formed as part of the second profile member  34  and depends from the guide post  52 .  
      As can be understood in  FIG. 2B , the first and second profile members  32 ,  34  engage and disengage with each other to open and close the resealable zipper closure  30 . Specifically, as pressure is applied to the profile members  32 ,  34 , the closure posts  40  and  50  interact with each other such that the first and second profile members releasably interlock with each other.  
      Referring now to  FIG. 2A , the zipper closure  30  further includes a slider device  56  mounted on the pair of profile members  32 ,  34  to facilitate the opening and closing of the zipper closure  30 . Specifically, the slider device  56  engages and disengages the first and second profile members  32 ,  34  as the slider is moved along the zipper closure  30  between the side edges  20  and  22 .  
      The slider device  56  includes a separation structure for separating the first and second profile members  32 ,  34 . The separation structure can extend or depend from a top wall of the slider housing. A preferred slider device is taught in U.S. Pat. No. 6,524,002, the disclosure of which is incorporated herein by reference. However, it should be understood that various other configurations for the slider device  56  can be utilized while operating within the scope of the present invention.  
      Referring now to  FIG. 1B , the zipper closure  30  includes a removed notch  58 . The removed notch  58  provides a home or parking position for the slider  56 . The removed notch  58  allows the separating device of the slider  56  to pass through the zipper closure  30  and permit the package to be fully closed. The zipper closure  30  further includes a slider stops  60  and  62  formed on opposite ends of the zipper closure. The slider stops  60 ,  62  prevent the slider  56  from traveling any further along the zipper closure  30 .  
      Referring now to  FIG. 1A , the reclosable package  10  includes a hood area  64  that extends above the zipper closure  30  and encloses the slider  56  prior to opening of the package. The hood area  64  is formed as a portion of both the first and second side panels and is set off from the remaining portions of the reclosable package by a line of weakness  66 . In the preferred embodiment of the invention, the line of weakness  66  is a line of perforations, although the line of weakness could also be formed from a laser score or die line, as required. As can be seen in  FIG. 1A , the line of weakness  66  is generally aligned with a notch  68  formed along each side of the reclosable package. The die line  66  includes a curved area and extends below the slider  56 , as illustrated. A line of weakness  66  allows the hood area  64  to be removed from the reclosable package  10  once the reclosable package has been formed, filled with product and sealed. The removal of the hood area  64  provides access to the zipper closure  30 , and specifically the slider  56 , to open and close the reclosable package as is well known.  
      The preferred method of forming, filling and sealing the reclosable package of the present invention will now be described with reference to the Figures. Referring first to  FIGS. 2A and 3 , the reclosable package  10  is initially formed by folding a continuous web of plastic material into the condition shown in  FIG. 3 . In this condition, the continuous web forms the side panels  12 ,  14  and the bottom wall  16 . While the continuous web is being folded to create the side panels  12  and  14 , a continuous length of the zipper closure  30  is fed between the side panels  12 ,  14 . The zipper closure  30  is formed from continuous, mated strips that form both the first profile member  32  and the second profile member  34 , as best shown in  FIG. 2 . The continuous length of zipper closure  30  includes individual sliders  56  spaced along the length of the zipper closure  30 . The sliders  56  are mounted along the length of the zipper closure at a bag width distance apart from each other such that each reclosable package includes one of the sliders  56 . The sliders can be installed onto the zipper closure  30  using various techniques, as is well known in the art.  
      Once the zipper closure  30  has been fed between the side panels  12 ,  14  of the continuous web of material, the individual side seals  20 ,  22  shown in  FIG. 1A  are formed between the opposed side panels. The side seals  20 ,  22 , along with the bottom wall of the reclosable package, define the open interior  18  of the reclosable package  10 , as shown in  FIG. 2A . In the preferred embodiment of the invention, the side seals  20 ,  22  are formed by a heated sealing bar, as is conventional.  
      Referring back to  FIG. 2A , when the side seals  20 ,  22  are created, the zipper closure  30  is secured at its ends  63  and  65  to both of the side panels  12 ,  14  along the respective side seals  20 ,  22 . As illustrated in  FIG. 2 , prior to filling the package with product, the zipper closure  30  is not attached to any other portions of the side panels  12 ,  14  other than along the side seals  20  and  22 .  
      Referring now to  FIG. 3 , after the side seals  20  and  22  are formed, the entire zipper closure  30 , including the attachment flanges  36  and  54 , are spaced inwardly from the respective side panels  12 ,  14 . Thus, the zipper closure  30  is movable across the open interior  18  to either side of the centerline between the side panels  12  and  14 , as illustrated by arrow  67 .  
      Once the reclosable package  10  has been formed, as shown in  FIGS. 2A and 3 , product  68  can be inserted into the open interior  18 , as shown in  FIG. 4 . In the embodiment of the invention shown in  FIG. 4 , the product  68  is filled through the open, top mouth  28  of the reclosable package  10 . Specifically, a product fill tube  70  is inserted into the open mouth  28  and directs a flow of product through a fill opening  72 . In the embodiment of the invention illustrated in  FIG. 4 , the zipper closure  30  is moved to the left of the centerline  74  and the fill opening  72  is between the zipper closure  30  and the side panel  12 . However, it is contemplated that the zipper closure  30  can be moved to the right of the centerline  74  and closer to the side panel  12  such that the fill opening  72  would be defined between the zipper closure  30  and the side panel  14 . Since the zipper closure  30  is attached to the side panels  12 ,  14  only along the side seals  20 ,  22  ( FIG. 2 ), the zipper closure  30  is movable across the open interior  18  of the reclosable package  10 . Thus, the product  68  can be filled past the zipper either between the zipper closure  30  and the first side panel  12  or between the zipper closure  30  and the second side panel  14 .  
      In the preferred embodiment of the invention, the zipper closure  30  is moved away from the centerline  74  by a known movement means. For example, the movement means could be a blast of pressurized air, mechanical fingers, or any other similar device that physically moves the zipper closure  30  to one side of the centerline  74 . The movement of the zipper closure  30  away from the centerline  74  creates the fill opening  72  to allow product  68  to be inserted into the open interior  18 .  
      Referring now to  FIG. 5 , once the desired amount of product  68  has been loaded into the open interior  18  of the package, the attachment flanges  36  and  54  of the zipper closure  30  are sealed to the side panels  12  and  14 . Specifically, the attachment flange  36  of the first profile member is sealed to the first side panel  12 , while the attachment flange  54  of the second profile member is secured to the second side panel  14 . In the preferred embodiment of the invention, the attachment flanges  36 ,  54  are sealed to the respective side panels  12 ,  14  by a pair of sealing bars  76 . Specifically, the sealing bars  76  are moved into contact with the side panels  12 ,  14  beneath the slider  56  of the zipper closure  30  and generally aligned with the bottom edges of the attachment flanges  36  and  54 . The sealing bars  76  provide the required heat to bond the attachment flanges  36  and  54  to the side panels  12  and  14 .  
      As illustrated in  FIG. 2B , both the attachment flanges  36 ,  54  include a thickened attachment area  78  near the lower ends of the respective attachment flanges  36 ,  38 . The thickened attachment areas  78  provide additional material to prevent the attachment flanges  36 ,  54  from sealing to each other during the attachment of the zipper closure  30  to the side panels  12 ,  14 , as shown in  FIG. 5 . The thickened attachment areas  78  are shown and described in U.S. Pat. No. 5,067,822, the disclosure of which is incorporated herein by reference.  
      In an alternate embodiment of the invention, each of the attachment flanges  36  and  54  can include a heat resistant layer formed along the inside surface of the respective attachment flange. The heat resistant layer also aids in preventing the attachment flanges  36 ,  54  from sealing together during the step shown in  FIG. 5 .  
      Referring back to  FIG. 5 , the zipper closure  30 , including the slider  56 , is included within the hood area  64 . The hood area  64  is defined at its top end by a seal  80  formed along the top edge of the reclosable package  10 . The seal  80  is created between the side panels  12 ,  14  and is positioned above the zipper closure  30 , as illustrated. The seal  80  is formed by a second pair of sealing bars  82  as illustrated. Preferably, the sealing bars  82  are heated to provide a fusion of the side panels  12 ,  14  along the top seal  80 .  
      Referring now to  FIG. 6 , a flange seal  84  is created between each of the attachment flanges  36 ,  54  and one of the side panels  12 ,  14 . The flange seal  84  extends across the entire width of the package from the side seal  20  to the side seal  22 .  
      As discussed previously, the line of weakness  66  is formed at each of the side panels  12 ,  14  and extends below the slider  56  when the reclosable package  10  is in its loaded condition, shown in  FIG. 6 .  
      As illustrated in  FIG. 7 , when the reclosable package  10  is filled with product  68 , the lower ends  86 ,  88  of the respective attachment flanges  36 ,  54  are sealed to the respective side panels  12 ,  14 . In this condition, the zipper closure  30  bridges the open interior and allows the reclosable package  30  to be repeatedly opened and closed through the use of the slider  56 . As discussed previously, the hood  64  is removable from the reclosable package  10  along the line of weakness  66 . Once the hood  64  has been removed, the zipper closure  30  can be used to repeatedly open and close the reclosable package  10 .  
      Referring now to  FIG. 8 , thereshown is a first alternate embodiment of the reclosable package  10  of the present invention. The alternate embodiment of the reclosable package  10  includes many corresponding elements, the reference numerals of which will be utilized in the following description. As illustrated in  FIG. 8 , the attachment flanges  36  and  54  are secured to the side panels  12 ,  14  along the flange seals  84  in a similar manner as described in  FIGS. 5-7 . However, in the second embodiment of the invention illustrated in  FIG. 8 , a releasable adhesive  86  is positioned beneath the lowermost portions of the attachment flanges  36 ,  54  to provide a seal across the width of the reclosable package  10  between the side panels  12 ,  14 . In the preferred embodiment of the invention, the releasable adhesive  86  is a conventional peel-seal. The peel-seal prevents product  68  from contacting the zipper closure  30  prior to initial opening of the package  10 . The peel-seal adhesive  86  thus provides another tamper-evident device in the reclosable package  10  of the second embodiment of the invention.  
      In the preferred embodiment of the invention shown in  FIG. 8 , the releasable adhesive  86  is applied to one of the side panels  12 ,  14  prior to product being inserted into the package, as illustrated in step  4 . Once product is inserted into the reclosable package  10 , the peel-seal adhesive  86  is activated to provide the seal illustrated in  FIG. 8 . It is contemplated that the releasable adhesive  86  can be applied to either of the side panels  12 ,  14 , or both, while operating within the scope of the present invention.  
      Referring now to  FIG. 9 , thereshown is a third alternate embodiment of the reclosable package  10  of the present invention. In the embodiment of the invention illustrated in  FIG. 9 , a membrane  88  is formed as part of the zipper closure  30 . The membrane  80  extends between the pair of attachment flanges  36  and  54 . Specifically, the first end  90  of the membrane  88  is attached to the outermost end  94  of the attachment flange  36 , while the second end  92  is attached to the outermost end  96  of the attachment flange  54 . The membrane  88  thus extends across the open interior  18  of the product package  10 . The membrane  88 , like the releasable adhesive  86  shown in  FIG. 8 , prevents product  68  from coming into contact with the zipper closure  30  prior to the initial opening of the product package. The membrane  88  includes a line of weakness (not shown) that allows the membrane  88  to separate during initial product opening. Thus, once the reclosable package  10  is opened for the first time, the membrane  88  ruptures and provides access to the product  68 .  
      In addition to providing additional separation between the product  68  and the zipper closure  30 , the membrane  88  also serves the additional purpose of preventing the sealing of the attachment flanges  36  and  54  during the attachment process shown in  FIG. 5 . The increased thickness caused by the ends  90 ,  92  of the membrane, prevent the attachment flanges  36 ,  54  from sealing together.  
      In the preferred embodiment of the invention, the membrane  88  is integrally formed with the mating first and second profile members. The membrane  88  can either be coextruded with the zipper closure or can be adhesively attached in a separate processing step.  
      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.