Patent Publication Number: US-8117804-B2

Title: Method of producing high burst zipper assemblies for large reclosable packages

Description:
This application is a continuation of application Ser. No. 11/728,405 filed Mar. 26, 2007, now U.S. Pat. No. 7,621,105, issued on Nov. 24, 2009 which claims priority under 35 U.S.C. §119(e) from provisional application Ser. No. 60/839,447, filed on Aug. 23, 2006, entitled “High Burst Slider Zipper for Large Bags and Method of Manufacture”, the contents of which are hereby incorporated by reference. application Ser. No. 11/728,405 was filed simultaneously with application Ser. No. 11/728,477 filed Mar. 26, 2007, now U.S. Pat. No. 7,963,007, issued on Jun. 21, 2011, entitled “High Burst Zipper Assembly for Large Reclosable Packages” and application Ser. No. 11/728,413 filed Mar. 26, 2007 entitled “Hot Melt Adhesive Systems for Zipper Assemblies on Large Bag Constructions of Various Substrates”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to zipper assemblies for reclosable packages which are large bags, particularly zipper assemblies which achieve high burst strengths, and the methods for manufacture thereof. These zipper assemblies may include sliders or may have a press-to-close configuration. 
     2. Description of the Prior Art 
     Large packages, bags or pouches, such as those used for pet food, charcoal, cat litter and similar items are typically filled and sealed shut, with no reclosure mechanism. These packages may be formed by form fill and seal (FFS) or by other methods. Prior attempts to incorporate a zipper reclosure mechanism have been unsatisfactory due to the unique requirements of a large bag with a relatively heavy load. In particular, filling from the bottom places all of the load on the reclosure during filling. This load can cause the zipper reclosure to fail and open. Similarly, dropping a filled bag onto a pallet or similar rough handling during transportation, as well as exposing a bag to elevated temperatures during transportation, can cause the zipper reclosure to fail. 
     The prior art has addressed these deficiencies by folding over the end of the package, particularly a multi-wall package, using an expensive label as tape thereby allowing successful filling and transport. Similarly, the prior art has addressed these deficiencies by using a liner peel seal below the zipper and a solid tear line in the zipper flange to provide a fill and transport system that does not rupture and spill the contents. However, these methods have slow rates of production, as well as increased costs of production, and frequently do not result in a satisfactory product for the consumer. 
     Some further examples of the prior art which are not entirely satisfactory are found in U.S. Pat. No. 6,979,482 entitled “Multiwall Bag with Zipper and Fin” issued on Dec. 27, 2005 to Hartzell et al. and U.S. Pat. No. 7,090,904 entitled “Enhanced Slider Zipper Multiwall Bag and Associated Methods” issued On Aug. 15, 2006 to Hartzell et al. 
     Typical prior tamper-evident zipper assemblies are disclosed in U.S. Pat. No. 6,354,738 entitled “Tamper Evident Reclosable Plastic Bag” issued on Mar. 12, 2002 to Buckman et al.; U.S. Pat. No. 4,637,063 entitled “Reclosable Bag with Sealed Laminated Liner and Method” issued on Jan. 13, 1987 to Sullivan; and U.S. Pat. No. 5,509,735 entitled “Closure Arrangement Having a Peelable Seal” issued on Apr. 23, 1996 to May. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a zipper assembly for reclosable packages, particularly large bags, formed by form fill and seal or other methods, which provides for high burst strength in bottom filling or top filling configurations, to allow the bags to withstand dropping or shock loading without the zipper reclosure bursting open. 
     It is therefore a further object of the present invention to provide such a zipper assembly without significant increases in manufacturing and related costs. 
     It is therefore a still further object of the present invention to provide a method of manufacture for a product achieving the above objects. 
     These and other objects are attained by providing a zipper assembly for reclosable packages, particularly large bags, wherein the flanges are sealed together with a peel seal or other frangible seal, and one of the flanges is folded so as to be sealed to itself above the peel seal. This causes the external forces on a bag from bottom filling or shock loading (or forces from within the bag, typically created when the bag is dropped on its top or side) to be directed toward the hard seal and redirecting the peel seal from a peel position to a shear position. As the force required to separate a peel seal in a shear position is several times greater than the force required to separate the peel seal in a peelable position, the load-bearing capacity of the package or bag is increased. 
     These and other objects are similarly obtained by providing a zipper assembly for reclosable package, particularly large bags, wherein one of the flanges is provided in two segments in a T-configuration, with the intersection of the two segments being above the peel seal. 
     These and other objects are similarly obtained by providing a zipper assembly for a reclosable package, particularly large bags, with a folded flange with a peel seal above the fold and a tear line or other frangible connection at the fold. 
     The slider zipper is thereby manufactured. In order to subsequently manufacture the reclosable package, the zipper assembly is subjected to a slider zipper process whereby the zipper is provided from a spool. The flanges on this ribbon are then spread open, typically by a vacuum or similar device, and an adhesive which is compatible with the bag substrate is applied to the inside face of the flanges. The zipper with adhesive is placed over a series of packages or bags and sealed thereto via a temporary application of pressure, typically with clamps, over the adhesive coated flanges. End stomps (typically two at a time) are formed on the zipper and sliders are sequentially mounted on the zipper. The portions of the flanges between the successive bags are heat sealed, glued, or ultrasonically bonded to each other. The zipper segment, and hence the completed package or bag, is then cut from the ribbon. For a gusseted package or bag, the gussets are glued or otherwise connected so that the gussets are under the zipper flange. 
     Adhesive sealing methods, particularly hot melt, cross-linkable adhesive (such as hot melt cross-linkable polyurethane reactive adhesive) sealing methods, may be preferred over heat sealing methods in order to reduce the electrical power requirements for the production site. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawings, wherein: 
         FIG. 1  is a plan view, partially in phantom, of a typical reclosable package incorporating the zipper assembly of the present invention. 
         FIG. 2  is a cross-sectional view along the upper portion of plane  2 - 2  of  FIG. 1 , showing the cross section of the zipper assembly of the present invention. 
         FIG. 3  is a cross-sectional view along the upper portion of plane  2 - 2  of  FIG. 1 , showing the cross section of an alternative embodiment of the zipper assembly of the present invention. Additionally, an alternative area of detail is shown with a variation of the alternative embodiment. 
         FIG. 4  is a cross-sectional view along the upper portion of plane  2 - 2  of  FIG. 1 , showing a cross section of a portion of the package or bag in an unstressed configuration. 
         FIG. 5  is a cross-sectional view along the upper portion of plane  2 - 2  of  FIG. 1 , showing a cross section of a portion of the package or bag when an internal load (i.e., a force from within the package or bag) is applied thereto. 
         FIG. 6  is a cross-sectional view of the upper portion of plane  2 - 2  of  FIG. 1 , showing a cross section of a portion of the package or bag and further showing the resultant forces on the zipper assembly when an internal load is applied to the package or bag. 
         FIG. 7  is a cross-sectional view of a first alternative embodiment of the zipper. 
         FIG. 8  is a cross-sectional view of a second alternative embodiment of the zipper. 
         FIG. 9  is a cross-sectional view of a third alternative embodiment of the zipper showing the use of reinforcing ribs on one profile. 
         FIG. 10  is a cross-sectional view of a fourth alternative embodiment of the zipper showing a tamper-evident removable hood. 
         FIG. 11  is a cross-sectional view of a fifth alternative embodiment of the zipper, which substitutes a secondary zipper-type assembly for the peel seal. 
         FIG. 12  is a cross-sectional view of the fifth alternative embodiment of the zipper, shown in a loaded position thereby putting the secondary zipper-type assembly into a shear configuration. 
         FIG. 13  is a cross-sectional view of the zipper profile, prior to attachment to the package or bag walls, and further prior to the stomping of the ends and the insertion of the sliders. 
         FIG. 14  is a perspective view of the zipper profile, prior to attachment to the package or bag walls, and further prior to the stomping of the ends and the insertion of the sliders. 
         FIG. 15  is a plan view of the vacuum device used to spread the flanges of the zipper prior to the adhesive insertion step. 
         FIG. 16  is a cross-sectional view of glue or similar adhesive being inserted onto the interior of the flanges of the zipper. 
         FIG. 17  is a schematic of the processing of the packages or bags after the zipper has been attached. 
         FIGS. 17A and 17B  are alternative plan views of the sealing of the flange ends of  FIG. 17 . 
         FIG. 18  is a plan view of the reclosable package or bag with the zipper attached thereto. 
         FIG. 19  illustrates a first alternative for manufacturing the zipper. 
         FIG. 20  illustrates a second alternative for manufacturing the zipper. 
         FIG. 21  illustrates a third alternative for manufacturing the zipper. 
         FIG. 22  is a cross-sectional view of a first alternative top-filling embodiment of the zipper. 
         FIG. 23  is a perspective view of the walls of the package, with strips of polyethylene, in preparation for the second alternative top-filling embodiment of the zipper, as shown in  FIG. 24 . 
         FIG. 24  is a cross-sectional view showing the second alternative top-filling embodiment of the zipper attached to the package walls. 
         FIG. 25  is a cross-sectional view showing the third alternative top-filling embodiment of the zipper attached to the package walls. 
         FIG. 26  is a cross-sectional view showing the fourth alternative top-filling embodiment of the zipper attached to the package walls. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  is a perspective view of a typical reclosable package  100 , such as a large bag, which incorporates the zipper assembly  10  of the present invention. Reclosable package  100  may be formed by form fill and seal or by other methods. Reclosable package  100  includes a front wall  102  and a rear wall  104 . Front and rear walls  102 ,  104  may be separate polymeric or multi-sheet panels sealed together at edges  106 ,  108 . Alternatively, front and rear walls  102 ,  104  may be provided as a single tube with or without a lap seal in the longitudinal direction. Front and rear walls  102 ,  104  may be formed from virtually any substrate in the packaging art—laminate films, plain polyethylene or polypropylene films, multi-wall paper, and polypropylene woven layer bags or any combination or hybrid thereof. Additionally, gussets (not shown) may be provided between front and rear walls  102 ,  104  at edges  106 ,  108 , or similarly at bottom  110 . 
     Bottom  110  may be sealed shut, or folded over and then glued. Reclosable package  100  is typically bottom filled, so that the seal or glued fold may be formed after filling. However, other methods of filling, such as top filling before the complete application of zipper assembly  10 , are equally applicable to the present invention and are disclosed herein. 
     A longitudinal seal or seam  111 , which can be a lap or fin seal or seam, may optionally be formed in a central longitudinal location on rear wall  104  and is shown in phantom on  FIG. 1 . 
     Mouth  112  is formed at the top of the reclosable package  100  of  FIG. 1 , and is reclosably sealed by zipper assembly  10 . 
     As shown in  FIGS. 1 and 2 , zipper assembly  10  is formed from polymeric materials and includes first profile  12 , second profile  14  and optional slider  15  (see  FIG. 1 ). First profile  12  includes first interlocking element  16  and first flange  18 . Similarly, second profile  14  includes second interlocking element  20  and second flange  22 . Optional slider  15  is mounted on first and second profiles  12 ,  14  and operates in a conventional manner by interlocking first and second interlocking elements  16 ,  20  of respective first and second profiles  12 ,  14  when moved in a closing direction and separating first and second interlocking elements  16 ,  20  of respective first and second profiles  12 ,  14  when moved in an opening direction. 
     Peel seal  24  is formed between central locations of first and second flanges  18 ,  22 . Peel seal  24  may be replaced by other frangible (and therefore tamper-evident) seals, or even a rip-cord (either supplementing or substituting for the peel seal  24 ). Peel seal  24  is more resistant to shear forces than to peeling forces. Peel seal  24 , or any substitutes therefor, particularly when loaded in a shear configuration, is typically sufficiently strong to support the loads required by bottom filling. Peel seal  24  is typically pre-activated, but may be activated at the time of package or bag conversion. Additionally, first flange  18  in  FIG. 2  includes upward fold  26  immediately or proximately below peel seal  24 . First flange  18  continues upward from upward fold  26  to downward fold  28 , wherein hard seal  30  is formed between a portion of first flange  18  above peel seal  24 . This configuration can be considered to divide first flange  18  into three portions—first portion  34  which extends from first interlocking element  20  to upward fold  26 , second portion  36  which extends from upward fold  26  to downward fold  28 , and third portion  38  extends from downward fold  28  to first distal end  40  thereby providing an area for sealing, gluing, or otherwise securing to front wall  102  of package  100 . Likewise, second flange  22  extends from second interlocking element  20 , past peel seal  24 , to second distal end  42  thereby providing an area for sealing, gluing, or otherwise securing to rear wall  104  of package  100 . As shown in  FIGS. 1 ,  4 ,  5  and  6 , first and second flanges  18 ,  22  are typically sealed, glued or otherwise secured to the upper exterior surfaces of front and rear walls  102 ,  104 . However, some embodiments may seal, glue or otherwise secure first and second flanges  18 ,  22  to upper interior surfaces of respective front and rear walls  102 ,  104 . 
     In the alternative embodiment of  FIG. 3 , second portion  36  of first flange  18  is omitted, so that first and third portions  34 ,  38  are separate sheets or segments of web. Third portion  38  is joined to a central location of first portion  34  by hard seal  30 . Alternatively, hard seal  30  can be omitted if first and third portions  34 ,  38  are formed integrally and simultaneously by extrusion, as shown in the alternative area of detail of  FIG. 3 . 
     In the configuration of either embodiment, as shown in  FIGS. 5 and 6 , the external forces on package  100  from bottom filling or shock loading (or forces from within the bag) are directed toward hard seal  30  (which is above the peel seal  24 ) and redirected so as to cause a shear force on peel seal  24 . As a peel seal is much more resistant to a shear force than a conventional peeling force, the resistance of package  100  to external or internal forces is greatly increased. 
       FIGS. 7 and 8  disclose embodiments, wherein first flange  18  is relatively short, extending from profile  16  and terminating upwardly adjacent to gap  25 . First flange  18  is sealed or otherwise joined to extension segment  46  at point  50 . Second flange  22  includes proximal segment  21  which extends from profile  20 . Second flange  22  further includes distal segment  23  which is joined to proximal segment  21  at fold  44  wherein a line of weakness, such as a perforated or scored line, is provided in order to provide additional tamper evidence after opening. Distal segment  23  extends upwardly from fold  44  and terminates downwardly adjacent to gap  25 . Second flange  22  is sealed or otherwise joined to extension segment  48  at point  52  and distal segment  23  is sealed or otherwise joined to first extension segment at point  54  and adjacent to peel seal  24 . The connections at points  50 ,  52 ,  54  are typically formed by heat sealing. Peel seal  24  is further formed between faces (or facing portions) of proximal segment  21  and distal segment  23 . 
     Extension segments  46 ,  48  are typically formed with nominal 6 mil film, but those skilled in the art will recognize a range of equivalents after review of this disclosure. Extension segments  46 ,  48  are joined, typically by adhesive, to front and rear walls  102 ,  104 , respectively. The embodiment of  FIG. 7  differs from that of  FIG. 8  in that the extension segment  48  of  FIG. 8  includes fold  56  between inner portion  57  and outer portion  59 . Inner portion  57  is sealed to second flange  22  at point  52  while outer portion  59  descends past flanges  18 ,  22 . 
     The alternative embodiment of  FIG. 9  includes reinforcing ribs  60  on flange  22  to increase the stiffness of flange  22 . The alternative embodiment of  FIG. 10  (based on the construction of  FIG. 3 ) includes tamper-evident header  62  formed of film enclosing zipper assembly  10 . Tamper-evident header  62  includes lines of weakness  64 ,  66 , typically formed by a perforated or scored line, in order to provide access to zipper assembly  10 . 
     The alternative embodiment of  FIG. 11  (unloaded) and  FIG. 12  (loaded) substitutes the separable connection of secondary zipper  27  for the separable connection of peel seal  24  of the previous embodiments. Secondary zipper  27  includes first interlocking profile  29  attached or sealed to first flange  18  and second interlocking profile  31  attached or sealed to second flange  22 . As shown in  FIG. 12 , the loaded configuration, or other forces from within the package  100 , causes a shear force to be applied to secondary zipper  27 . Secondary zipper  27 , similar to peel seal  24 , resists a shear force to a much greater extent than a peeling force thereby increasing the strength of the resulting package when in the loaded configuration of  FIG. 12 . The possibility of the substitution of the secondary zipper  27  for the peel seal  24  is envisioned for all of the disclosed embodiments of zipper assembly  10 . 
     The manufacturing process of reclosable package or bag  100  is illustrated in  FIGS. 13-18 . A continuous length of interlocked zipper profiles  12 ,  14  is illustrated in  FIGS. 13 and 14  and is typically provided from a spool  190  (see  FIG. 17 ). The flanges  18 ,  22  of zipper profiles  12 ,  14  are then spread apart, typically by a spreader apparatus  192  such as is illustrated in  FIG. 15  (also see  FIG. 17 ) wherein the portion of flanges  18 ,  22  immediately below the interlocked profiles  12 ,  14  is fed into the nip  200  between rollers  202 ,  204 . A portion of flanges  18 ,  22  extends therefrom and is engaged by vacuum elements  206 ,  208 . Vacuum elements  206 ,  208  spread the portions of flanges  18 ,  22  extending from rollers  202 ,  204  so that adhesive, typically a hot-melt reactive adhesive such as a hot melt, cross-linkable adhesive (particularly, a hot melt cross-linkable polyurethane reactive adhesive), can be applied or otherwise placed by nozzle  210  onto the interior of flanges  18 ,  22  as shown in  FIG. 16  (those skilled in the art will recognize that some adhesives should be applied by a downwardly pointing nozzle  210  with the orientation of the flanges  18 ,  22  during adhesive application changed in accordance therewith). Additionally, optional plasma or corona discharge station  209  may change the surface energy (described later in detail herein) of the flanges  18 ,  22  prior to application of adhesive. The flanges  18 ,  22  are temporarily clamped by clamps  194  (see  FIG. 17 ), or pressure similarly applied, to the outside bag walls  102 ,  104  of successive packages or bags  100  (typically supplied with an open bottom and free of contents). 
     The adhesive layer is typically applied to flanges  18 ,  22  in a path divergent or parallel to the bag supply so that the flanges  18 ,  22  are subsequently guided from the divergent or parallel path to a position wherein the bag walls are captured within the flanges  18 ,  22 . 
     Zipper  10  is stomped at stomp locations  68  at package-width intervals, typically two stomps  68  at a time, by stomper  220  and slider  15  is inserted therebetween by slider inserter  222  as shown in  FIG. 17 . The laterally extending excess portions of the flanges are heat sealed, glued, or ultrasonically bonded to each other by bonding station  224 . 
       FIG. 17A  illustrates a possible configuration for the flanges  18 ,  22  to be sealed to each other in an inverted T-shaped area  400  below end stomp  68  between successive bags  100  by bonding station  224 .  FIG. 17B  illustrates a possible configuration for the flanges  18 ,  22  to be glued to each other in rectangular area  402  between edges of successive bags  100  and below end stomp  68 . 
     The zippers are then cut at cutting station  226  to achieve the package  100  illustrated in  FIG. 18  (with the phantom lines illustrating a gusset between the front and rear walls). The resulting packages or bags  100  are typically unfilled and have an open bottom. Optional filling station  225  is illustrated prior to cutting station  226 . Optional filling station  225  may be top filling (in which case, zippers such as illustrated in  FIG. 22  or  24 - 26  may be used) or bottom filling (in which case, the packages or bags are inverted and a bottom sealer is included with the filling station  225 ). However, separate subsequent filling steps may be performed at a different location to fill packages or bags  100  with contents and seal the bottom  110  of the package or bag  100 . 
     Alternative embodiments may cut the zippers prior to the application of the adhesive, may include pre-mounted sliders, or sliders inserted and stomps formed prior to the gluing process. Walls  102 ,  104  may be folded to form gussets prior to the securing of the zipper assembly  10  thereto. Similarly, gussets may be attached below or within the flanges  18 ,  22  by glue dots or similar connection methods. To reinforce the gussets underneath the zipper assembly  10 , glue may be applied in between the inside faces of the gussets or in between the outside faces of the gussets. 
       FIGS. 19 ,  20  and  21  illustrate variations in the formation of the zipper assembly  10 .  FIG. 19  illustrates how first and second sheets of web  300 ,  302  can be joined by peel seal  24 , a fold  28  formed in second sheet of web  302  and then sealed to first and second flanges  18 ,  22  thereby achieving a construction similar to  FIG. 2 . Similarly,  FIG. 20  illustrates first and second profiles  12 ,  14  being joined by peel seal  24  and first sheet of web  300  being slit into two pieces which are sealed to flanges  18 ,  22  thereby forming a construction similar to that illustrated in  FIG. 3 . In  FIG. 21 , a lower portion of first flange  18  is removed and then resealed to an upper portion of first flange  18  thereby likewise forming a construction similar to that illustrated in  FIG. 3 . Alternatively, first flange  18  can be folded to achieve the construction of  FIG. 2 . Further alternatively, the T-shaped configuration of first flange  18  can be achieved by simultaneous extrusion of a single T-shaped flange. 
     With respect to the adhesive used by nozzle  210  to fasten the zipper assembly  10  to the walls  102 ,  104  of package  100 , it has been found that hot melt, cross-linkable adhesives (such as hot melt polyurethane reactive adhesive which are cross-linkable) have been found to be superior to ordinary hot melt adhesives, both for multi-wall paper and woven polypropylene walls. Likewise, this adhesive has been found superior for the construction of all seams of package or bag  100 , including bottom seam  110  and longitudinal seam  111 . This was determined by tests in which the package  100  was loaded with 2.5 times its rated load and hung upside down (that is, with the load bearing on the zipper assembly  10 ) and placed in 140 degree Fahrenheit environment (which is representative of temperatures which may be encountered during shipping) for seventy-two hours. The package  100  was considered to have passed this test if the package  100  maintained its integrity during this period. 
     Likewise, this test can be performed for the same load (2.5 times rated load) and period (seventy-two hours) at negative 20 degrees Fahrenheit (−20° F.) for simulation of cold environments which may be encountered during transportation and storage in some climates. The hot melt, cross-linkable adhesives (such as hot melt polyurethane reactive adhesive which are cross-linkable) have likewise been found to be superior under these tests and can be applied to all seams of packages, with or without a reclosable zipper. 
     Similarly, it has been found that pre-treatment of the olefin structures of the walls  102 ,  104  (particularly if made from woven polypropylene) and zipper flanges, typically by corona discharge or plasma treatment of the walls and flanges, improves the adhesion bond of the hot melt, cross-linkable adhesive (such as hot melt cross-linkable polyurethane reactive adhesive) between the walls and zipper flanges, particularly for film structures having a non-polar surface energy of less than 40 dynes per square centimeter. 
     Additionally, heat sealing may be effective in instances wherein the bag surface includes resin binder type inks. 
     As shown in  FIG. 22 , in the first alternative top-filling embodiment of zipper assembly  10 , distal ends  40 ,  42  of respective segment  38  and second flange  22  are attached to respective front and rear walls  102 ,  104  prior to the attachment or sealing of segment  38  to first flange  18 . Segment  38  is typically a polyethylene strip that is attached by glue to the bag wall prior to the filling of the package or bag and by a heat seal to flange  18  after the package or bag is filled. This allows the package to be filled with contents through the gap or opening  37  between segment  38  and first flange  18  prior to the joining or sealing of segment  38  to first flange  18 . This top filling eliminates the bottom filling typically associated with many of the other disclosed embodiments. 
     As shown in  FIG. 23 , in the second alternative top-filling embodiment of zipper assembly  10 , polyethylene strips  103 ,  105  are attached to the exterior of front and rear walls  102 ,  104  immediately adjacent to mouth  112 . Extension segment  46  is typically heat sealed or otherwise attached to polyethylene strip  103  prior to filling of the package  100  and extension segment  48  is typically heat sealed or otherwise attached to polyethylene strip  105  after filling of the package  100  to reach the configuration shown in  FIG. 24 . While  FIG. 24 , as well as  FIG. 25 , is illustrated with the zipper assembly  10  of  FIG. 7 , other equivalent zipper configurations could be substituted for this zipper assembly  10 , as would be recognized by those skilled in the art after review of this disclosure. 
       FIG. 25  shows a third alternative top-filling embodiment of zipper assembly  10 , similar to that shown in  FIG. 24 , except that extension segment  46  is glued to front wall  102 , typically by hot melt, cross-linkable adhesive (such as hot melt cross-linkable polyurethane reactive adhesive)  107  prior to filling of the package  100 , thereby obviating the need for polyethylene strip  103 . After filling of package  100  with contents, similar to the embodiment shown in  FIG. 23 , extension segment  48  is heat sealed to polyethylene strip  105  on rear wall  104 . 
       FIG. 26  illustrates a zipper assembly  10 , similar to that of  FIG. 3 , wherein flange  22  and segment  38  are glued or otherwise sealed or attached to front and rear walls  102 ,  104  prior to the formation of peel seal  24 . Peel seal  24  is formed and activated thereby joining first and second flanges  18 ,  22  to each other after the filling of package  100  with contents between first and second interlocking elements  16 ,  20  as shown by arrow labeled as “fill”. This filling may be done by using the slider (see  FIG. 1 ) to separate the first and second interlocking elements  16 ,  20 , filling between first and second interlocking elements, and then using the slider to interlock first and second interlocking elements  16 ,  20 . 
     Those skilled in the art will recognize a broad range of possible contents for the packages  100 , including, but certainly not limited to, charcoal, pet food, livestock or other animal food, cat litter, fertilizer, seeds, plant bulbs, rock salt, and foodstuffs. 
     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.