Abstract:
A resealable package integrity closure includes a film layer forming a top of container and having a flap defining an access opening to gain access to the contents of the container. A sealing panel completely covers the flap of the film layer. A releasable adhesive is provided on either or both the film layer and the sealing panel for adhering the sealing panel to the film layer. The sealing panel is releasable from the film layer by pulling the sealing panel back in a peeling direction and reclosable against the top to seal the access opening when the sealing panel is moved back against the top. A coating of transferable material is provided on either the sealing panel or on the film layer, which is transferable therebetween, respectively, when the sealing panel is pulled back from the film layer for a first time to provide a visual indication that the closure has been previously opened.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a resealable closure for packages storing articles and, more particularly, resealable closures for packages having a package integrity indicator. 
     BACKGROUND OF THE INVENTION 
     Some containers for food products, such as cookies and other snacks, typically include an outer wrapper. In one type of container, the wrapper surrounds a frame which acts as a tray to hold the food product and to protect the food product from damage. Other food products come packaged in plastic trays, such as thermoform trays which are sealed on the top using some type of lidding material. One recent advancement in the art of food container closures includes a resealable closure disclosed in U.S. Pat. No. 6,918,532 (hereinafter “the &#39;532 patent”), herein incorporated by reference, which discloses a wrapper which forms a top of the container, which has an access opening covered by a resealable sealing panel. 
     In the packaging art, different methods have been used to indicate whether a package has been previously opened or whether the integrity of the package has been compromised, which is often referred to in the art as “tamper-evident.” For example, in the tissue wipes packaging art of U.S. Pat. No. 6,428,867 (hereinafter “the &#39;867 patent”), a means for indicating package integrity includes a tamper-evident tab with one or more ink layers which is initially an integral part of a sealing panel prior to the package being opened for a first time. The tab is transferred with one of the ink layers from the sealing panel to the top of the package when the closure has been opened for a first time. Tamper-evidence is indicated in a misalignment of the sealing panel with an image on the transferred tab, which is visible through a transparent outer layer of the sealing panel, after the sealing panel has been resealed to the top of the package. 
     There is a need for improvement in the art for package integrity indicators for a resealable closure, preferably suitable for use with a resealable closure for containers or packages containing food items. 
     SUMMARY OF THE INVENTION 
     The present invention generally relates to a resealable closure for a container formed from a two-ply material, which has a package integrity indicator in the form of a coating of material, such as ink or paint, which transfers between a sealing panel and a film layer disposed therebelow when the container has been opened for a first time. 
     The present invention, in one form, comprises a package integrity closure comprising a film layer forming a top of a container and having a flap defining an access opening to gain access to the contents of the container. A sealing panel completely covers the flap of the film layer. A releasable adhesive is provided on either or both the sealing panel or the film layer for adhering the sealing panel to the film layer. The sealing panel is releasable from the film layer by pulling the sealing panel back in a peeling direction and reclosable against the top to seal the access opening when the sealing panel is moved back against the top. A coating of transferable material is disposed on either the film layer adjacent the access opening on a surface facing the sealing panel or on the sealing panel on a surface facing the film layer. The coating is transferable from either the film layer or sealing panel to the sealing panel or the film layer, respectively. The coating transfer occurs without a transfer of a portion of the film layer or sealing panel bonded to the coating when the sealing panel is pulled back from the film layer for a first time to thereby provide a visual indication that the closure has been previously opened. The sealing panel can either be a top layer of a multilayer material forming the top of the container, such as the container disclosed in U.S. patent application Ser. No. 11/500,497, herein incorporated by reference, or a discrete label applied over a film layer forming the top of the container, such as the container of the &#39;532 patent. Further, the perimeter edge of the sealing panel can be either linear or nonlinear such as a zigzag pattern. 
     Advantageously, the coating of transferable material is a different color or pattern than that of the film layer or sealing panel. If the coating is initially applied to the sealing panel, evidence that the closure has been previously opened is observable in the form of a partial outline of the coating transferred to the film layer adjacent the sealing panel, which is visible due to a slight misalignment of the sealing panel with the film layer when the sealing panel is reapplied to the top of the container upon closure. If the perimeter edge of the sealing panel is nonlinear, such as a zigzag pattern, a slight misalignment of the zigzag pattern between the sealing panel and the film layer will be visible as a slightly misaligned pattern. 
     A secondary evidence of package integrity is provided in the form of a reduction in peel force between the sealing panel and the film layer after the closure has been previously opened and subsequently resealed due to a deadening effect resulting from the transfer of the coating from the sealing panel or film layer to the adhesive on the opposite surface or the transfer of adhesive with coating material from either the film layer or sealing panel to the opposite surface. 
     The present invention, in another form thereof, concerns a package integrity indicating closure comprising an at least two-ply material comprising a first film layer adhesively joined to a second film layer. A first tear line is formed in the first film layer defining a first panel for providing an access opening through the first film layer when separated from the first film layer along the first tear line. A second film layer having a second layer tear line defines a sealing panel which completely covers the first panel. The sealing panel is releasably adhered to the first film layer, such that the sealing panel is separable from the first film layer to expose the access opening. A coating of transferable material is on either the sealing panel on a surface facing the first film layer or on the first film layer facing the sealing panel so that upon opening the closure, a portion of the coating is transferred from between the second film layer and the first film layer to provide a visual indication that the closure has been opened after the sealing panel has been peeled back from the first film layer for a first time. 
     The present invention, in another form thereof, concerns a package integrity indicating closure for a container comprising an at least two-ply material comprising an inner layer adhesively joined to an outer layer and forming a top of the container. The inner layer has an inner layer panel and the outer layer has a sealing panel formed therein, which completely covers the inner layer panel. The first panel and the sealing panel are permanently joined to each other to provide an access opening into the container. A releasable adhesive is provided on one or both the sealing panel and the inner layer for adhering the sealing panel to the inner layer. The sealing panel is releasable from the inner layer by pulling the sealing panel back in a peeling direction and reclosable against the top to seal the opening when the sealing panel is moved back against the top. A coating of transferable material is on either the sealing panel or on the inner layer facing the sealing panel so that upon opening the closure, a portion of the coating is transferred from between the sealing panel and the inner film layer to provide a visual indication that the closure has been opened after the sealing panel has been peeled back from the inner layer for a first time. 
     The present invention, in another form thereof, relates to a package integrity indicating food container comprising a tray and an at least two-ply material comprising an inner layer adhesively joined to an outer layer to form a top over the tray. The top is formed to provide an access opening for access to the food items disposed in the tray. The inner layer has a first panel and the outer layer has a sealing panel formed therein, which completely covers the first panel. The first panel and sealing panel are permanently joined to each other to form the access opening into the container. A coating of transferable material is on either the outer layer adjacent the access opening on a surface facing the inner layer or the inner layer facing the sealing panel. A releasable adhesive is provided on either or both the inner layer on a perimeter outside the first panel or the sealing panel, which lies thereover for adhering the sealing panel to the inner layer. The sealing panel is releasable from the inner layer by pulling the sealing panel layer back in a peeling direction and reclosable against the top to seal the opening when the sealing panel is moved back against the top whereby, upon opening the closure for a first time, a portion of the coating is transferred from between the outer layer and the inner layer to provide a visual indication that the closure has been opened. 
     Food items disposed in the container may include cookies, crackers, peanuts, cheese, sliced meats and semi-solid foods. 
     Other features and advantages of the present invention are stated in or apparent from detailed descriptions of the presently preferred embodiments of the invention found herebelow. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of a package including an exemplary closure prior to an initial opening, according to the present invention; 
         FIG. 2A  is the package of  FIG. 1 , shown in a partially opened condition; 
         FIG. 2B  is a partial enlargement of the package of  FIG. 1 , after the package has been opened and subsequently closed; 
         FIG. 2C  is an enlarged partial plan view of a package, similar to the one of  FIG. 1 , with an alternative sealing panel, in accordance with the present invention; 
         FIG. 3  is a partial plan view of a sealing panel with attached film layer flap of the package of  FIG. 1 , as viewed from below, in its initial condition; 
         FIG. 4  is a partial plan view of the top of the package of  FIG. 1 , with the sealing panel not shown, prior to the package being opened; 
         FIG. 5  is a partial enlarged cross-sectional view of the closure of  FIG. 1 , taken along line  5 - 5  of  FIG. 1 ; 
         FIG. 6  is a partial enlarged cross-sectional view of the closure, similar to  FIG. 5 , depicting an initial opening of the closure; 
         FIG. 7  is a perspective view of another package including an exemplary closure prior to an initial opening, according to another embodiment of the present invention; 
         FIG. 8A  is the package of  FIG. 7 , shown in a partially opened condition; 
         FIG. 8B  is a partial enlargement of the package of  FIG. 7 , after the package has been opened and subsequently closed; 
         FIG. 9  is a partial plan view of a sealing panel with attached film layer flap of the package of  FIG. 7 , as viewed from below, in its initial condition; 
         FIG. 10  is a partial plan view of the top of the package of  FIG. 7 , with the sealing panel not shown, prior to the package being opened; 
         FIG. 11  is a partial enlarged cross-sectional view of the closure of  FIG. 7 , taken along line  11 - 11  of  FIG. 7 ; 
         FIG. 12  is a partial enlarged cross-sectional view of the closure, similar to  FIG. 11 , depicting a resealed configuration of the closure after the initial opening; 
         FIG. 13  is a perspective view of another package including an exemplary closure prior to an initial opening, in accordance with another aspect of the present invention. 
         FIG. 14A  is the package of  FIG. 13 , shown in a partially opened condition; 
         FIG. 14B  is a partial enlargement of the package of  FIG. 13 , after the package has been opened and subsequently closed; 
         FIG. 15  is a partial plan view of a sealing panel with attached film layer flap of the package of  FIG. 13 , as viewed from below, in its initial condition; 
         FIG. 16  is a partial plan view of the top of the package of  FIG. 13 , with the sealing panel not shown, prior to the package being opened; 
         FIG. 17  is a partial enlarged cross-sectional view of the closure of  FIG. 13 , taken along line  17 - 17  of  FIG. 13 ; 
         FIG. 18  is a partial enlarged cross-sectional view of the closure similar to  FIG. 17  depicting an initial opening of the closure; and 
         FIG. 19  is a perspective view of another package, including a closure that has been opened, in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures and, in particular,  FIGS. 1-6 , there is shown package  10  with closure  11 , which incorporates a package integrity feature. Package  10  includes a two-ply wrapper comprising a first, inner film layer  12  and a second, outer film layer  13 , forming a top or upper surface  14 , sides  16 , lower surface (not shown), and crimped ends  18 , 19 . The inner film layer  12  and outer film layer  13  are formed from a polymeric film or other flexible material that has been cut, folded or otherwise pressed to define an inner space or receptacle for receiving the desired product, such as food items, to be provided within the package  10 . Package  10  can be used to store and distribute food items such as cookies, crackers, candy or other items. The outer film layer  13  may include graphics or other indicia to identify the contents of the package  10 . 
     Advantageously, the inner film layer  12  is coextensively formed and adhesively joined to the outer film layer  13 . During the manufacturing of package  10 , the inner film layer  12  is die cut along first tear line  20  and the outer film layer  13  is die cut along a second tear line  21 , as disclosed in U.S. Patent Application Publication No. 2005/0276525, herein incorporated by reference. 
     The first tear line  20  is formed as a continuous tear line to define a panel  22 . The panel  22  is separated from the remainder of the inner film layer  12  to expose an opening  24  ( FIGS. 2A  ,  4  and  6 ), whereby access to the contents of the package  10  may be gained. 
     The second tear line  21  defines sealing panel  26  of the outer film layer  13 . The sealing panel  26  extends beyond the periphery of the first tear line  20 , adjacent to the opening  24 , so that the sealing panel  26  completely covers and extends beyond the perimeters of the panel  22 . 
     The side of the sealing panel  26  which faces the inner film layer  12  is coated with a releasable adhesive  27  (see  FIGS. 2   a ,  3 ,  5  and  6 ) so that the sealing panel  26  may be releasably secured to the inner film layer  12  at a position adjacent to the panel  22 . Alternatively, or along with resealable adhesive  27 , resealable adhesive  27  can be coated on the inner film layer  12  adjacent the outside perimeter of the panel  22 . The releasable adhesive can be any pressure sensitive adhesive which allows resealing and includes, but is not limited to, the adhesives disclosed in U.S. Patent Application Publication No. 2006/0144911, herein incorporated by reference. The sealing panel  26  is provided with a tab  30  or other gripping feature which is not coated with the adhesive  27  so that the sealing panel  26  may be peeled back from the inner film layer  12  to open the package  10 . 
     A coating of transferable material  28 , such as ink or paint, is disposed or otherwise printed on a perimeter edge  34  of the sealing panel  26  on top of the adhesive  27 . Coating  28  is any appropriate transferable paint or ink known in the packaging art including but not limited to those disclosed in U.S. Patent Application Publication No. 2006/0257599, herein incorporated by reference. 
     Alternatively, coating  28  can be applied directly to the sealing panel  26  rather than on top of adhesive  27 . Adhesive  27  can either be applied to the sealing panel adjacent the coating only or on top of the coating as well. 
     Adhesive  29  is applied along the inner film layer  12  approximate the second tear line  21 . Adhesive  29  can be any known adhesive in the art which, advantageously, has a bond strength between the adhesive  29  and the coating  28  which is greater than the bond between the coating  28  and the sealing panel  26  and the bond between coating  28  and adhesive  27 . When the closure  11  is opened for a first time, a portion of the coating  28  will be transferred from the sealing panel  26  to the adhesive  29  covered portion of the inner film layer  12 , as will be discussed in greater detail below. 
     In an alternative embodiment, there is no adhesive  29  applied along the inner film layer  12 . Instead, coating  28  forms a sufficiently strong bond with the inner film layer  12  such that upon opening closure  11  for a first time, some or all of the coating  28  will be transferred from the sealing panel  26  to the inner film layer  12 . 
     As shown in  FIGS. 5 and 6 , the first panel  22  is separated from the remainder of the inner film layer  12  along the first tear line  20  and remains adhered to the sealing panel  26  as the sealing panel  26  is peeled back in a peeling direction indicated by arrow  32  ( FIGS. 2A and 5 ) to open the package  10 . After the contents of the package have been accessed and it is desired to reseal the package  10 , the sealing panel may be reapplied to the inner film layer  12 , approximately in its original position, as depicted in  FIG. 2B . Because the sealing panel  26  extends beyond the periphery of the panel  22 , the releasable adhesive  27  disposed thereon facilitates the resealing of the package  10  with the panel  22  positioned over the access opening  24 . 
     In addition, when the sealing panel  26  is peeled away from the inner film layer  12  to separate the panel  22  for a first time, a portion of the coating  28 , namely transferred coating  28   a , is separated from the sealing panel  26  and remains or adheres to the adhesive  29  disposed on the inner film layer  12 . Advantageously, the color of the coating  28  is different than the color of the top surface of the package  10 . Although a residual amount of coating  28  is depicted, alternatively, all of coating  28  can be transferred from the sealing panel  26  to the inner film layer  12 . 
     Referring specifically to  FIG. 2B , when the sealing panel  26  is reapplied to the top of the package  10 , due to inevitable slight misalignment of the sealing panel  26  relative to the inner film layer  12 , a portion of the transferred coating  28   a  will be visible and thus indicate that the package  10  has been previously opened. 
     In addition to the visual indication, package integrity is further evident after the package has been previously opened and resealed due to a deadening effect of adhesive  29  due to the transfer of the coating  28  thereto. As a result, the transferred coating  28   a  deadens the adhesive  29  along the portions where the coating  28   a  has been transferred. Consequently, a previously opened package, having a deadened portion of the adhesive  29 , is easier to open a second and subsequent time than it is initially. 
     An alternative embodiment to package  10  is depicted in  FIG. 2C  where like elements are raised by  100 . Package  110  is shown as a partial plan view and is identical to package  10 , except the tear line in the outer film layer  121  has a zigzag pattern rather than the linear tear line  21  of package  10 . All other features of closure  111  are identical to those of closure  11 . Following an initial opening and resealing of closure  111 , the transfer coating  128   a  will appear as a misaligned zigzag pattern with the pattern of second tear line  121 , thus indicating that the closure  111  has been previously opened. 
     Referring now to  FIGS. 7-12 , in an alternative embodiment where like elements to the package  10  have been increased by  200 , package  210  includes closure  211 , a film layer  214  forming the top sides and crimped ends  218 ,  219 . The film layer  214  is die cut along tear line  220 . A sealing panel  226  is adhesively sealed to the top surface of package  210 . 
     Referring now specifically to  FIGS. 9 and 10 ,  FIG. 9  shows the sealing panel  226  with flap  222  and  FIG. 10  shows the top of package  210  with the sealing panel not shown for simplification to illustrate the various layers and surfaces prior to an initial opening of the closure  211 . A coating of transferable material  228  is initially disposed around the perimeter of opening  224  on film layer  212 , in a similar manner as coating  28  is applied to package  10 . Advantageously, the coating  228  is applied to portions of the film layer  212  that will be in direct contact with a releasable adhesive  227  of the sealing panel  226  when the sealing panel is placed over top  214  of package  210 . Advantageously, the coating  228  has a weaker bonding strength to the film layer  212  than the bond strength of the coating  228  to the releasable adhesive  227 . 
     When the sealing panel  226  is pulled back for a first time, some or all of the coating  228 , for example, transferred coating portion  228   a , will be transferred from the film layer  212  to the releasable adhesive  227 , thus deadening those portions of the adhesive  227  now covered with transferred coating  228   a , as shown in  FIGS. 8A and 12 . The transfer of the coating  228  to the sealing panel  226  provides a visual indicia to alert customers that the sealing panel  226  has already been peeled back, thus providing indicia of package integrity, as shown in  FIG. 8A . In addition, package integrity is provided by a reduction in peel force between the sealing panel  226  and the film layer  212  due to the deadened areas of the adhesive  227  where the coating  228   a  has now been transferred after the package  210  has been previously opened. It should be noted that the coating  228  can be deposited partially or totally around the perimeter of the access opening  224 . In addition, further visual indicia is provided by viewing a portion of coating  228  observable when viewing the top  214  of package  210  due to slight misalignment of the sealing panel  226 , as shown in  FIG. 8B . 
     An additional alternative embodiment of a package with a package integrity feature, in accordance with the present invention, is provided in  FIGS. 13-18 , where like elements to those of package  10  are increased by  300 . Package  310  is identical to package  210 , except that rather than a coating of transferable material being initially applied to the film layer  214 , a coating of transferable material  328  is first applied to the perimeter edge  334  of the sealing panel  326  prior to applying a releasable adhesive  327 , as shown in  FIGS. 15 and 17 . Advantageously, the coating  328  can be applied to the back surface of sealing panel  326  using reverse printing. Advantageously, portions of the print layer of coating  328  are specially treated so as to weaken a bonding strength between the coating  328  and the label face stock of the sealing panel  326 . 
     When the package  310  is opened for a first time, a portion of the adhesive  327  bonded to the coating  328  will be transferred from the sealing label  325  to the film layer  312  to form transferred coating  328   a  to the top of the package  310 . (See  FIGS. 15-18 .) As a result, the transfer coating  328   a  creates a visual indicia on the top  314  of the package  310 , which is visible due to slight misalignment of the sealing panel  326  with the film layer  312  when the sealing panel  326  is returned to its flat position, as shown in  FIG. 14B . In addition, there will be a reduction in peel force between the sealing panel  326  and the film layer  312  after the package  310  has been opened and resealed for a first time due to portions of the sealing panel  326  missing portions of the adhesive  327 , which is now transferred to the top  314  of the film layer  312  with coating  328   a.    
     While  FIGS. 1-18  show and describe closures  11 ,  111 ,  211  and  311  as forming the opening of a wrapper which defines packages  10 ,  110 ,  210  and  310 , the closure may form a top of other packages having resealable openings, such as those described in U.S. patent application Ser. No. 11/193,613, herein incorporated by reference and, thus, the closure can form a closure over a thermoform tray having a sealing panel or layer as a lidding material over the top of the tray. 
     Referring to  FIG. 19 , where like elements to those of the embodiments of  FIGS. 1-6  are increased by  400 , package  410  comprises a thermoform tray  460  which forms sides  416  and ends  461 ,  462 . A two-ply film material comprising an inner film layer  412  and outer film layer  413  are sealed to flange  463  of the thermoform tray  460 . Like packages  10 ,  110 ,  210 ,  310 , pulling back tab  430  separates the sealing panel  426  from the outer film layer  413  and separates the panel  422  from the inner film layer  412 . 
     As with package  10 , package  410  has a coating of transferable material  428  deposited on the perimeter  434  of the sealing label  426  and adhesive  427  formed around the perimeter of the inner film layer  412  adjacent the second tear line  421 , which lies directly underneath the coating  428  when the sealing panel is laid flat on the top  414  of the package  410 . Like package  10 , peeling back the sealing panel  426  for a first time transfers a portion of the coating  428  to adhesive  429 . When the sealing panel  426  is returned to its flat position, a portion of the transferred coating  428   a  will be visible when viewing the top of the package  410 , due to a slight misalignment of the sealing panel  426  with the inner layer  412 , in a similar manner as with package  10 . 
     Although package  410  is described as having closure  411 , package  410  can incorporate any of the closures  11 ,  111 ,  211  and  311 . It will now be evident to one of ordinary skill in the art that the present resealable package with package integrity features provides advantages not found in prior packages. 
     Although the invention has been described above in relation to preferred embodiments thereof, it will be understood by those skilled in the art that variations and modifications can be effected in these preferred embodiments without departing from the scope and spirit of the invention.