Abstract:
A closure element incorporated into a flexible bag to reclose a bag opening includes a resilient structure which carries an adhesive strip. The closure element is secured to one wall of the bag and the resilient strip seals the one wall to the respective other wall of the bag when the walls are pressed together and the resilient structure is compressed. The resilient structure is held compressed by the adhesive strip. In one embodiment, the resilient structure includes a base portion and a wing portion which deflects to allow the adhesive strip to make contact with the other wall. In another embodiment, the base portion deflects to flatten against the wing portion, the wing portion secured to the bag wall. The base portion and the wing portion can be provided with engageable elements which snap together or interlock to provide a closing feel to the closure strip as the adhesive strip seals the bag opening.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    The present invention relates to recloseable openings, such as for flexible bags. Particularly, the present invention relates to a closure strip using a resealable adhesive portion which at least partly defines a recloseable opening, the closure strip attached to a wall of a flexible bag.  
         BACKGROUND OF THE INVENTION  
         [0002]    Closure strips for recloseable bags are generally known. One type of closure strip includes interlocking profile strips which typically include interlocking tongue and groove elements to seal a bag opening, such as described in U.S. Pat. Nos. 4,756,629, 5,806,984 or 4,909,017.  
           [0003]    Another type of closure strip uses a resealable adhesive strip. The resealable adhesive strip uses a removable pressure sensitive adhesive to close a bag opening. A “removable pressure sensitive adhesive” is one which can be peeled off, together with the backing to which it is applied, from a substrate surface without damage to either the adhesive or the substrate. U.S. Pat. Nos. 5,035,518; 4,645,711; 4,599,265; 4,629,663; 3,608,707; 3,922,464; 4,902,142; and 4,709,399, describe pressure sensitive adhesives and/or packaging using pressure sensitive adhesives.  
           [0004]    One drawback to interlocking profile strips is that the strips are relatively thick compared to the thickness of the web material which comprises the front and back wall of the associated bag. This relatively increased thickness is required in order to form the interlocking tongue and groove of the interlocking profile strips. The increased thickness of the profile strip requires higher sealing temperature, pressure and dwell time in the formation of the bag. These additional considerations adversely affect the speed and throughput of the bag forming machines.  
           [0005]    Resealable adhesive strips suffer the drawback that the strips lack a positive closing which gives the user indication or “feedback” of a complete closure of the resealable bag.  
           [0006]    The present inventor has recognized that it would be advantageous to provide a recloseable strip for a bag that has a low profile thickness and which also provides a positive closure indication to the user.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a recloseable closure strip for an opening, such as for a flexible bag. The closure strip includes an adhesive region and at least one flexible member which deflects during engagement of the adhesive region to an adhesive receiving region of the bag during re-sealing. The deflection of the flexible member provides a positive closing indication or feedback to the user during re-sealing.  
           [0008]    The flexible member can be part of a resilient structure which carries the adhesive region such that by engaging the closure strip to reclose the bag, the resilient structure is compressed or squeezed from a relaxed or uncompressed condition to a flattened condition, giving the user a positive feel or indication of the re-sealing of the bag opening. The resilient structure can be significantly thinner in profile than the prior known interlocking profile strips due to the fact that it is functioning only as an indication of sufficient re-sealing pressure and does not perform a sealing function.  
           [0009]    The bag can include a companion strip to the closure strip, the companion strip providing an adhesive receiving area or “land” for the adhesive region of the closure strip. The companion strip can be plain or can have a coacting adhesive applied thereto. The adhesive region of the closure strip and the land of the companion strip can include, rather than tacky adhesives, cold sealable, pressure sensitive cohesives which are adherent to each other and are not tacky and adherent to other surfaces.  
           [0010]    The closure strip of the invention can include interlocking elements which interlock when the resilient structure is compressed to its flattened condition simultaneously with the adhesive strip contacting the land, to give the user a positive indication of the re-sealing of the bag opening. The resilient structure can include a base portion and a wing portion, one of which is connected to a first wall of the bag, the wing portion extending obliquely from the base portion, and the base portion carrying the adhesive strip. The interlocking elements can be applied one on the base portion and one on the wing portion to interlock when the base portion and the wing portion are flattened together.  
           [0011]    The interlocking portions function differently than that of conventional closures since they do not lock the closure, but instead only give the closure the same “feel” or indication of re-sealing as do interlocking closures, but which utilizes an adhesive as the re-sealing means with the adhesive acting independently of the interlocking action of the interlocking portions. 
       
    
    
       [0012]    Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view of a recloseable bag that incorporates the present invention;  
         [0014]    [0014]FIG. 1A is a perspective view of another embodiment recloseable bag incorporating the present invention;  
         [0015]    [0015]FIG. 1B is a perspective view of a further embodiment recloseable bag incorporating the present invention;  
         [0016]    [0016]FIG. 2 is a fragmentary sectional view of a portion of the bag taken generally along line  2 - 2  of either FIG. 1 or FIG. 1A;  
         [0017]    [0017]FIG. 2A is a perspective view of a closure element taken from FIG. 1 or FIG. 1A;  
         [0018]    [0018]FIG. 2B is a perspective view of a roll of closure element material;  
         [0019]    [0019]FIG. 3 is a sectional view of the portion shown in FIG. 2 but in a closed configuration;  
         [0020]    [0020]FIG. 4 is a fragmentary sectional view of a first alternate embodiment closure element incorporated into a bag;  
         [0021]    [0021]FIG. 5 is a fragmentary sectional view of a second alternate embodiment closure element incorporated into a bag;  
         [0022]    [0022]FIG. 6 is a fragmentary sectional view of a third alternate embodiment closure element incorporated into a bag and in an open condition;  
         [0023]    [0023]FIG. 7 is a fragmentary sectional view of the closure element of FIG. 6 in a closed condition;  
         [0024]    [0024]FIG. 8 is a fragmentary sectional view of a fourth alternate embodiment closure element incorporated into a bag and in an open condition; and  
         [0025]    [0025]FIG. 9 is a fragmentary sectional view of the closure element of FIG. 8 in a closed condition. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawing and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.  
         [0027]    [0027]FIG. 1 illustrates a bag  15  having a front wall  16   a  and a back wall  16   b.  The bag is formed by folding a sheet of web material and forming a longitudinal seam  25  on the back wall  16   b.  The bag is sealed between the front wall  16   a  and the back wall  16   b  at a top seam  40  and at a bottom seam  42 . A line of perforations  43  can be provided along the top seam  40  for initially opening the bag. Alternatively, the top seal  40  can be a non-resealable adhesive or a heat seal as is known, which can be pulled open to initially open the bag. A closure element  20  is applied transversely to the longitudinal direction or formation axis A of the bag  15 . The formation axis A is that axis along which bags are formed connected end-to-end and thereafter separated to form individual bags. The bags and closure elements can be assembled in an apparatus as described in U.S. Pat. Nos. 4,909,017; 3,608,707; 4,617,683; or 6,003,582, all herein incorporated by reference.  
         [0028]    [0028]FIG. 1A illustrates a bag  115 , which is formed along an alternate formation axis A′. Bags in this embodiment are connected side-by-side along the formation axis A′ before being separated into individual bags. In this bag  115 , the closure element  20  is arranged longitudinally, parallel to the formation axis A′.  
         [0029]    [0029]FIG. 1B illustrates a bag  215  which is formed along the formation axis A as in FIG. 1. In this bag  215  however, the closure element  20  is arranged longitudinally, parallel to the formation axis A.  
         [0030]    [0030]FIG. 2 illustrates a closure element  20  secured to the front wall  16   a  of the bag  15 ,  115 , by a known method, such as by a heat seal  23 . Alternately, the closure element could be secured to the back wall  16   b  of the bag.  
         [0031]    In this embodiment, the closure element  20  is shaped as a trough  22  with wing portions  22   a,    22   b  which diverge from a base portion  22   c.  A resealable adhesive layer or strip  24  is arranged along the trough  22  on the base portion  22   c.  The adhesive layer can be a removable pressure sensitive adhesive such as described in U.S. Pat. Nos. 5,035,518; 4,645,711; 4,599,265; 4,629,663; 3,608,707; 3,922,464; 4,902,142; and 4,709,399, all herein incorporated by reference. Between the back wall  16   b  and the adhesive strip  24 , a bag opening  17  is defined.  
         [0032]    [0032]FIG. 2A illustrates in perspective the closure strip  20  isolated from the remaining bag components. The strip  20  includes a trough-like structure formed by the wing portions  22   a,    22   b  and the base portion  22   c.  The adhesive portions  24  is applied onto the base portion  22   c  along the length of the element  20 .  
         [0033]    [0033]FIG. 2B illustrates that the closure element  20  can be wound in a spool  50 . The closure element material can thereafter be dispensed, cut and applied to individual bags in an apparatus, such as described in U.S. Pat. Nos. 4,617,683 or 6,003,582, for applying profile strip fasteners.  
         [0034]    As illustrated in FIG. 3, the back wall  16   b  and the front wall  16   a  are compressed together by a user&#39;s fingers to close the bag opening  17 . This action compresses or flattens the trough  22 , by resiliently flattening the wing portions  22   a,    22   b  until the adhesive layer  24  is contacted against the front wall  16   a.  The adhesive layer  24  has a sufficiently strong adherence to the back wall  16   b  to retain the wing portions  22   a,    22   b  in their flattened states.  
         [0035]    Unlike prior known adhesive tapes used to create recloseable bags, the present configuration allows the user the ability to feel the closure strip flex and seal to determine whether the seal is positively closed. The wing portions  22   a,    22   b  create a spring effect. This feature allows the user to recognize the indication that a positive closure has been achieved since the overall thickness of the closure element  20  is substantially decreased when compressed and retained into the closed condition. Additionally, a failure of the adhesive layer  24  to adequately seal is indicated if the adherence is insufficient to retain the resilient wing portions  22   a,    22   b  in their flattened state, i.e., the closure element  20  will spring to its uncompressed, thicker, profile.  
         [0036]    An additional advantage of the embodiment of FIGS. 2 and 3 is that when the closure element  20  is compressed flat it is substantially only a single thickness closure which can approach the same thickness as the bag wall material as shown in FIG. 3.  
         [0037]    As illustrated in FIG. 4, a second strip or a companion strip  29  can be arranged on the back wall  16   b  opposite the closure element. The second strip  29  can carry an adhesive layer  30  facing the closure element.  
         [0038]    [0038]FIG. 4 also illustrates a modified closure element  20 ′ which includes wing adhesive portions  24   a,    24   b  applied onto the wing portions  22   a,    22   b  respectively. When the back wall  16   b  is compressed toward the front wall  16   a,  the second strip  29  flattens the wing portions  22   a,    22   b  against the back wall  16   b.  The adhesive regions  24 ,  24   a,    24   b  compress against the adhesive region  30  to close the opening  17 ′ defined between the modified closure element  20 ′ and the second strip  29 .  
         [0039]    The adhesive strips  24 ,  24   a,    24   b  and  30  can be formed from coadhesives, as known in the art, that will only adhere to like coadhesives, thereby resisting potential contamination from particles of the contained product within the bag, or external particles. A cold sealable, pressure-sensitive cohesive, such as described in U.S. Pat. No. 4,898,787, can be applied to the closure strip and the companion strip. This cohesive has low surface tack and is cohesive only when placed under pressure in contact with other cold sealable cohesive coated surfaces. Thus, the closure strip and the companion strip would not be tacky and adherent to non-coated surfaces such as the product held in the bag, or debris. U.S. Pat. No. 4,898,787 is hereby incorporated by reference.  
         [0040]    An additional advantage of the configurations described in FIG. 4 is that when the bag walls  16   a,    16   b  are initially compressed together to seal the opening  17 ′, the adhesive regions  24   a,    24   b  first seal against the front wall  16   a  or the additional strip  29  (with or without adhesive layer  30 ) forming a prone trapezoidal profile channel before the closure  20  is completely flattened. This trapezoidal channel will progress along the length of the closure  20  as the closure is progressively sealed by the user&#39;s fingers sliding along the length of the closure element through the bag walls. As the user&#39;s fingers reach the end of the closure element, air trapped within the trapezoidal space is expelled (with a “snap” sound) which gives the user an additional feedback or indication that the bag has been sealed with sufficient pressure.  
         [0041]    [0041]FIG. 5 illustrates an alternate closure element  220  having wing portions  222   a,    222   b  that are arranged angled toward each other inwardly, having a decreasing clearance between wing portions taken forwardly of the base portion  222   c.  During closing, the wing portions are resiliently compressed until the adhesive region  224  engages the front wall  16   a,  or alternately, engages a companion strip  29  such as illustrated in FIG. 4. The wing portions  222   a,    222   b  are folded against the base  222   c  and have a length such as to not interfere with the adhesive portion  224 .  
         [0042]    [0042]FIG. 6 illustrates a further alternate embodiment closure element  300  connected to the front wall  16   a,  and a second strip  304  connected to the back wall  16   b.  The closure element  300  and the second strip  304  are substantially in alignment. The elements  300 ,  304  are connected by heat sealing, or other known method, to the bag walls  16   a,    16   b,  respectively. The closure element  300  includes at least one base portion  306  carrying an adhesive region  324  which faces the second strip  304 . The base portion  306  is connected to a wing portion  330 . The wing portion  330  is heat sealed or otherwise secured to the front wall  16   a.    
         [0043]    The base portion  306  and the wing portion  330  have formations which lock together when the base portion is flattened by pressing force from the strip  304 . Particularly, the base portion  306  has a hook portion  336  which engages an angled edge or face  338  of the wing portion  330 . The locking engagement provides a sensory field to the user that the closure element  300  is being sufficiently sealed to the strip  304 .  
         [0044]    Although a second strip  304  is illustrated, in some applications, the second strip can be eliminated and the adhesive strip  324  sealed directly to the bag back wall  16   b.  Alternately, a second strip of adhesive can be applied to the second strip or to the back wall to engage the adhesive strip  324  such as the arrangement illustrated in FIG. 4.  
         [0045]    [0045]FIG. 7 illustrates the closure element of FIG. 6 in a closed condition. The base portion  306  is pressed flat to the wing portion  330 , and the hook portion  336  has engaged the edge  338  of the wing portion  330  in a snap-fitting fashion to give the user a positive indication of the complete closure of the bag opening.  
         [0046]    [0046]FIG. 8 illustrates another embodiment closure element  400  which includes a base portion  406  resiliently attached to a wing portion  430 . The base portion  406  carries an adhesive strip  424  facing the back wall  16   b  of the bag. When the bag is closed, the back wall  16   b  engages the adhesive strip  424  to seal the bag opening. A second strip can be applied to the bag opposite to the closure element  400 , such as shown as  304  in FIGS. 6 and 7. Also, a second strip of adhesive can be applied to the second strip or to the back wall to engage the adhesive strip  424  such as illustrated in FIG. 4.  
         [0047]    The base portion  406  includes a tongue portion  440  which is aligned to register with a groove  442  formed in the wing portion  430 . The tongue portion is sufficiently sized to provide a resilient fit or squeeze fit within the groove so that a user is provided with a positive feel of resealing the bag. The pressure required to seat the tongue portion  440  within the groove is sufficient to ensure that the adhesive has been sufficiently pressed to the back wall  16   b  (or to the second strip on the back wall as applicable).  
         [0048]    An additional advantage of the closure element embodiments of FIGS. 2 through 5 is that the wing portions are such as to tend to shelter the adhesive strip from contamination, particularly from products being removed from the bag, past the closure strip. The products tend to be directed or deflected away from the adhesive portion by the presence of the extending wing portions.  
         [0049]    Although in the above embodiments the closure strip is described as being attached to the front wall of the bag, the closure strip could be attached to the back wall of the bag and any companion strip attached to the front wall of the bag without departing from the scope of the invention.  
         [0050]    Many of the various embodiments of the invention could be interchanged, such as the companion strip of FIGS. 4 and 6 and the cohesive properties of the closure of FIG. 4 could be utilized by any of the embodiments, given an application of cohesive material on the strip and on the coacting companion strip or bag wall. The bags of FIGS. 1, 1A or  1 B could be formed with the closure strips at an orientation other than those illustrated such as rotated 90°, to name just a few examples.  
         [0051]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.