Abstract:
The present disclosure relates to methods for forming reclosable bags with slider zippers which can be used in high pressure pasteurization. In particular, these methods form reclosable bags with a shroud formed over the slider zipper, with a patch or cap for protecting the slider during high pressure pasteurization. When the user tears the shroud from the bag, the patch or cap remains attached to the shroud but releases from the slider. An alternative embodiment forms an air pocket in the shroud to protect the slider.

Description:
[0001]     This application is a divisional of U.S. patent application Ser. No. 11/173,581, filed on Jul. 1, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention pertains to a slider zipper assembly with a shroud that has high pressure pasteurization protection attached to the inside thereof. The present invention further pertains to a method for application of the zipper assembly to the film to form a reclosable package.  
         [0004]     2. Description of the Prior Art  
         [0005]     High pressure pasteurization (HPP) of food-containing packages is accomplished by placing the package in a chamber that is typically raised to 85,000 psi for a predetermined time period. Typical reclosable food packaging with “press to close” zippers will survive high pressure pasteurization. However, packages containing slider zipper assemblies have proven to be problematic. The zippers are typically enclosed in the packaging by the top portion of the packaging film, known as the shroud. During the high pressure pasteurization process, the extreme pressure pushes the shroud film onto the slider with such force as to punch holes in the film, rendering the package useless.  
         [0006]     Commonly assigned U.S. patent application Ser. No. 11/020,607 entitled “Sleeve Cover for Slider”, filed on Dec. 23, 2004, the contents of which are hereby incorporated by reference, discloses a semi-soft sleeve cover to shield the slider during high pressure pasteurization. Likewise, commonly assigned U.S. patent application Ser. No. 11/103,751 entitled “Reclosable Package with Slider Zipper Shielded for High Pressure Pasteurization”, filed on Apr. 12, 2005, the contents of which are hereby incorporated by reference, discloses a shrouded reclosable bag wherein the slider shield is secured to the tear-away header so that the slider shield and the tear-away header are removed as a single piece. While these solutions are effective for their intended purpose, further improvements are desired with respect to the automated manufacture of these reclosable packages, particularly in combination with form fill and seal methods.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0007]     It is therefore an object of the present invention to provide a method and apparatus for producing a slider assembly that is suitable for use in a reclosable package that is processed with high pressure pasteurization.  
         [0008]     It is therefore a further object of the present invention to improve the automation of the production of reclosable bags with slider zippers which are suitable for high pressure pasteurization.  
         [0009]     It is therefore a still further object of the present invention to achieve the above objects in combination with a form fill and seal method and apparatus.  
         [0010]     These and other objects are attained by providing a slider zipper assembly that contains a slider zipper profile, a slider clip, a film shroud formed over the zipper and a protective device inside the shroud for the purpose of protecting the slider clip during the high pressure pasteurization process. The protective device may include a molded or extruded soft cap over the slider, a semi-soft patch over the slider, a continuous film section containing a semi-soft layer, or a heavier gauge film strip over the slider with or without a sealed air pocket over the slider.  
         [0011]     The slider zipper assembly is produced in a form ready for direct application to the film in a food packaging machine. The method of application includes the steps of feeding the slider zipper assembly from a continuous reel into the form fill seal machine along the with the package film. The slider zipper assembly is sealed to the film at the zipper flanges to form the top of the food package. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]     Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:  
         [0013]      FIG. 1  is a top plan view of the film strip in the various stages of forming the first embodiment of the shrouded zipper assembly of the present invention.  
         [0014]      FIG. 2  is a cross-sectional view along plane  2 - 2  of  FIG. 1 .  
         [0015]      FIG. 3  is a cross-sectional view along plane  3 - 3  of  FIG. 1 .  
         [0016]      FIG. 4  is a cross-sectional view along plane  4 - 4  of  FIG. 1 .  
         [0017]      FIG. 5  is a plan view of a second embodiment of the shrouded zipper assembly of the present invention wherein an air pocket is formed to provide further shielding of the slider.  
         [0018]      FIG. 6A  is a cross-sectional view along plane  6 - 6  of  FIG. 5 .  
         [0019]      FIG. 6B  is an alternative cross-sectional view along plane  6 - 6  of  FIG. 5 .  
         [0020]      FIG. 7A  is a plan view of the manufacturing process, in further detail of the shrouded zipper of the present invention.  
         [0021]      FIG. 7B  is a cross-sectional view along plane  7 B- 7 B of  FIG. 7A .  
         [0022]      FIG. 8  is a plan view of the embodiment of  FIG. 7A , illustrating subsequent steps.  
         [0023]      FIG. 9  is a cross-sectional view along plane  9 - 9  of  FIG. 8 , prior to application of the second sheet of film.  
         [0024]      FIG. 10  is a cross-sectional view similar to that along plane  9 - 9  of  FIG. 8 , after the application of the second sheet of film.  
         [0025]      FIG. 11  is a cross-sectional view showing a further alternative embodiment to  FIG. 10 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  shows the film strip  100  in the various stages of forming the first embodiment of the shrouded zipper assembly  10  of the present invention. As shown near plane  2 - 2  of  FIG. 1  and the cross-sectional view of  FIG. 2 , film strip  100 , with first and second longitudinal edges  102 ,  104 , is typically initially provided in a planar configuration. This configuration would be typical for the film strip  100  being provided from a roll as shown in  FIG. 7 , as will be discussed hereinafter. The slider shield  12  is placed on film strip  100  and secured thereto using a sufficiently strong adhesive, or tack seal, that slider shield  12  stays attached to film strip  100  during the removal of the resulting tear-away header, as described in U.S. patent application Ser. No. 11/103,751 entitled “Reclosable Package with Slider Zipper Shielded for High Pressure Pasteurization”, filed on Apr. 12, 2005, the contents of which are hereby incorporated by reference. As described in this commonly owned application, slider shield  12  is made from material typically chosen from silicone, foamed polymeric materials, elastomeric sheet materials, tape, or polymer films with a thickness greater than that of the film forming the reclosable bag. Those skilled in the art will recognize a range of equivalents after study of the present disclosure.  
         [0027]     Thereafter, as shown near plane  3 - 3  of  FIG. 1  and the cross-sectional view of  FIG. 3 , slider  14  of zipper  16  is laid below (in the perspective and orientation shown in  FIG. 1 ) the longitudinal mid-line of slider shield  12  and typically joined thereto by an adhesive which is relatively weak compared to the adhesive or tack seal holding the slider shield  12  to film strip  100  thereby allowing slider shield  12  to detach from slider  14  while remaining attached to the tear-away header formed from film strip  100 . Zipper  16  includes first and second profiles  18 ,  20  with respective first and second flanges  22 ,  24 . First flange  22  is sealed to film strip  100  along first seal line  106 . Alternately, flanges  22 ,  24  can be sealed to film strip  100  as shown in  FIG. 4 , and strip  100  sealed to bag walls  150 ,  152 , or both flanges  22 ,  24  and film strip  100  can be sealed at the same time to bag walls  150 ,  152 . Tear lines  110 ,  112  are also provided as previously indicated. Additionally, first line of weakness  110  is formed in film strip  100  between slider shield  12  and first seal line  106 . Likewise, second line of weakness  112  is formed in film strip  100  between slider shield  12  and where second seal line  108  (described hereinafter) is formed.  
         [0028]     Thereafter, as shown near plane  4 - 4  of  FIG. 1  and the cross-sectional view of  FIG. 4 , film strip  100  is thereafter folded around a longitudinal mid-point thereof and first and second longitudinal edges  102 ,  104  are brought together so that slider shield  12  is brought around slider  14  and secured thereto by a relatively weak adhesive. Second flange  24  is sealed to film strip  100  inwardly adjacent from second longitudinal edge  104  along second seal line  108 .  FIG. 4  is shown with a variation including a loop  200  in film strip  100  formed above slider  14 .  
         [0029]     A further embodiment is shown in  FIGS. 5, 6A  and  6 B wherein an air pocket  130  is formed in lieu of a slider shield  12 . Air pocket  130  is formed by a strip  132  sealed to the interior of the shroud formed by film strip  100  as shown in  FIG. 6A . Lower and upper bag walls  150 ,  152  are sealed to and extend from first and second flanges  22 ,  24 . Alternatively, as shown in  FIG. 6B , upper bag wall  152  can extend past second flange  24  whereby upper bag wall  152  forms the interior wall of air pocket  130  while film strip  100  forms the exterior wall of air pocket  130 . In other words, edge  153  of upper bag wall  152  is sealed to film strip  100  and edge  101  of film strip  100  is sealed to upper bag wall  152 .  
         [0030]     As shown in  FIG. 5 , air pocket  130  is bounded by end seal  160 , cross seal  162  and longitudinal seals  164 ,  166 .  
         [0031]     A further process is shown in detail in  FIGS. 7A and 8 . A continuous roll of semi-soft or similar material  380  (such as slider shield  12  is made from) is supplied from roll  300 , wherein material  380  extends over and above the edge  302  of film  304 , which forms one bag wall of the reclosable bag to which one side of material  380  is applied. As shown in  FIG. 7B , material  380  is indexed with patches  306  of relatively strong adhesive  382  on one side (the sides that are applied to the bag walls) and relatively weak adhesive  384  on the other side (the sides that are applied to and over the slider  14 ). Non-stick layers of film  400 ,  402  are applied on both sides of material  380  to prevent the adhesive patches  306  (comprising strong and weak adhesive  382 ,  384 ) from sticking to the material  380 , with non-stick layers of film  400 ,  402  being peeled off as material  380  is unwound. The adhesive patches  306  are indexed, depending on the size of the bag to which they are to be applied, to the position that slider  14  will have when the zipper  16  is attached to the bag walls. Zipper  16  with mounted sliders  14   A ,  14   B ,  14   C  is attached to bag wall  304  at location  309  SO that the sliders  14  are, as indicated, indexed to the adhesive patches  306 . Lower flange  22  (see  FIG. 9 ) of zipper  16  is sealed to film  304  at seal  106 . Material  380  is then folded over sliders  14   A ,  14   B ,  14   C  and pressed onto the sliders. The sliders  14   A ,  14   B ,  14   C  are now attached to continuous folded material  380  by the indexed adhesive patches with weak adhesive  384 , while strong adhesive patches  382  attach material  380  to bag wall  304 . Thereafter, cut-outs  160  are punched out through the folded soft material  380  and the lower bag film  304  at the locations of future cross seals, because material  380  would otherwise impede satisfactory cross seals. To cover punched out cut-outs in bag wall  304 , film strip  180  is introduced from roll  320  from below bag wall  304  and continuously sealed by seal bars  340  and  342  to bag wall  304  at seals  162 ,  164 . Perforations or tear line  110  can be formed in bag wall  304  at this time or earlier in the process. Bag wall  352 , which can be from a separate film, is applied over the zipper  16 , and sealed to bag wall  304  at seal  354 . Alternately, bag wall  304  can be folded over the zipper to form bag wall  352 . Simultaneously, bag wall  352 , with preformed perforation or tear line  112 , is pressed onto the strong adhesive patches  382  on the outside of material  380  (see  FIG. 10 ). Alternately, the same process can be used to attach material  380  to a separate strip, which is then attached to the film(s), forming the bag walls as shown in  FIG. 11 .  
         [0032]     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.