Abstract:
A high strength plastic bag is formed from two sheets of polymeric material. The sheets are folded, machined, and heat sealed to form a receptacle portion, a flap for covering an opening to the receptacle portion, and a handle having three layers of polymeric material for improved strength. The bag includes a tamper-indicating closure and has a high friction coefficient to prevent sliding of stacked bags.

Description:
FIELD OF THE INVENTION 
     This invention relates to plastic bags, and more particularly to a high strength plastic bag. 
     BACKGROUND OF THE INVENTION 
     Plastic bags have been widely used to contain various articles. Such plastic bags include tamper-indicating bags, which have been used to secure sensitive or valuable items during transit. These tamper-indicating bags have often been used to transfer money in the form of paper money, checks, or coins. The use of plastic bags to transfer coins presents several problems, however. For example, when plastic bags are used to accommodate more than a small number of coins, the bags need to be strong so they do not rupture under the weight of the coins. To make carrying the bag easier, the plastic bags require a means for grasping the bag. Prior plastic bags having handles to permit a user to grasp the bags are limited with respect to the amount of coins which may be contained in the bag because the heavy weight of a large number of coins tends to tear the bag at the handle. Furthermore, conventional plastic bags are susceptible to sliding against one another, making it difficult to stack the bags atop one another. 
     There is thus a need for a high strength plastic bag which may be used to contain and transport coins, and which overcomes the drawbacks of prior art plastic bags. 
     SUMMARY OF THE INVENTION 
     The present invention provides a high strength plastic bag which may be used to contain and carry heavy items, such as coins. The bag is formed from two sheets of polymeric material which have been, folded, die stamped, and heat sealed to create a receptacle portion, a handle portion, and a flap portion. The handle portion of the bag includes an aperture which permits a user to grasp the bag and comprises three sheets of high strength polymeric material that have been joined with heat seals to provide added strength to the handle. 
     The flap portion of the bag covers an opening to the receptacle and may be sealed over the opening with a tamper-evident adhesive to secure the bag. In one aspect of the invention, the flap portion further includes a removable receipt which may be detached from the bag for record keeping purposes. In another aspect of the invention, a second removable receipt is formed on the handle portion of the bag. 
     In yet another aspect of the invention, the bag is formed from polymeric material having a high friction coefficient so that the bags may be stacked atop one another without slipping. 
    
    
     The features and objectives of the present invention will become more readily apparent from the following Detailed Description taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. 
     FIG. 1 is a perspective view of an exemplary plastic bag of the present invention; 
     FIG. 2 is a cross-section of the bag shown in FIG. 1, taken along lines  2 — 2 ; and 
     FIG. 3 is a cross-section of the bag of FIG. 2, depicting the bag in a sealed condition with first and second receipts detached from the bag. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-3, there is shown an exemplary plastic bag  10  of the present invention. The plastic bag  10  is formed from two sheets of plastic material  12 ,  14 . The first sheet  12  is folded in an overlapping manner and heat sealed to form an interior compartment. First sheet  12  is also folded together with the second sheet  14  to form a handle for carrying the bag  10 . As formed, the bag  10  includes a receptacle portion  16 , a handle portion  18 , and a flap portion  20 . The receptacle portion  16  of the bag  10  is formed by folding the first sheet  12  over itself to form a first folded edge  22  and first and second overlapping layers  24 ,  26 . When the side edges  28 ,  30  of the folded sheet are heat sealed, the first and second layers  24 ,  26  of the first sheet  12  form a compartment  32  defined by the sealed edges  28 ,  30  and the first folded edge  22 . The interior of the compartment  32  may be accessed by an opening  33  created by the unsealed free edge  34  of the second layer  26 . 
     The handle and flap portions  18 ,  20  of the bag  10  are formed by folding the first layer  24  of the first sheet  12  back over itself to create a second folded edge  36  whereby the free edge  38  of the first layer  24  extends beyond the free edge  34  of the second layer  26 . The second plastic sheet  14  is inserted between the folds of the first layer  24  of the first sheet  12  so that at least part of the handle portion  18  comprises three layers of plastic. The handle portion  18  further includes an aperture  40  formed through the three layers of the handle portion  18  at a distance from an end of the bag  10 . In an exemplary embodiment, the aperture  40  is formed a distance of approximately 2½ to 4 inches from an end of the bag  10 . In another exemplary embodiment, the aperture  40  is formed at least approximately 3 inches from an end of the bag  10 . The aperture  40  is surrounded by a heat seal around its perimeter. Upper and lower heat seals  42 ,  44  above and below the aperture  40  join the three layers of plastic material. 
     The second sheet  14  of the handle is a polymeric sheet which has been developed for strength and heat sealability. It can be formed from standard polyolefins, blends or coextrusions. In an exemplary embodiment, the second sheet has inner and outer layers formed from a blend of linear low density ethylene and metalocene and a stiffening middle layer, such as high density polyethylene (HDPE). 
     The flap portion  20  extends over the opening  33  formed by the free edge  34  of the second layer  26  of the first sheet  12  to form a closure for the bag. In the exemplary embodiment shown, the bag  10  is provided with an adhesive  46  applied to the second layer  26  of the first sheet  12  near the opening  33  created by the free edge  34 , whereby the flap  20  may be bonded to the second layer  26  to seal the bag  10 . A release liner  47  may be provided over the adhesive  46  to protect the adhesive  46  from contamination and to prevent premature bonding prior to sealing the bag  10 . In an exemplary embodiment, the adhesive  46  is a tamper-indicating adhesive and the bag  10  is printed with tamper-indicating ink near the opening  33 , as described more fully in U.S. Pat. No. 6,196,716 to Geyer, herein incorporated by reference in its entirety. After the bag  10  is sealed as described above, the tamper-indicating adhesive  46  provides an indication of when the flap portion  20  has been opened the first time. In this manner, the plastic bag  10  provides a secure means for containing sensitive or valuable items. 
     The plastic bag  10  further includes one or more receipt portions  48 ,  50  which may be removed from the bag  10  for record keeping purposes. In the exemplary embodiment shown, the bag  10  includes two receipt portions  48 ,  50  which may be removed from the bag  10 . A first receipt portion  48  is removably attached to the handle portion  18  of the bag  10 , and a second receipt portion  50  is removably attached to the flap portion  20  of the bag  10 . In the exemplary embodiment, the receipt portions  48 ,  50  are formed by perforations  51 ,  53  formed on the bag  10  a distance from the edges  36 ,  38  of the handle and flap portions  18 ,  20  to create a removable strip of plastic material. Ink or other visible material may be applied to the bag  10  to create viewable areas  52  for marking the bag  10  with indicia  54 . Such markable areas  52  are particularly useful on the receptacle and receipt portions  16 ,  48 ,  50 , but may be applied to any portion of the bag  10  as desired. 
     A high strength plastic bag  10  as described above may be formed from two sheets of plastic material  12 ,  14  according to the following exemplary method. The first sheet  12  of polymeric material is folded to form a first folded edge  22  and first and second overlapping layers  24 ,  26  whereby the first layer  24  extends beyond a free edge  34  of the second layer  26 . A second sheet  14  of polymeric material is positioned on a portion of the first layer  24  of the first sheet  12 , at a distance from the free edge  34  of the second layer  26 . The first layer  24  of the first sheet  12  is folded over the second sheet  14  and a portion of the second layer  26  of the first sheet  12  to sandwich the second sheet  14  between the folds of the first layer  24 , forming a second folded edge  36  and a flap  20  which covers the free edge  34  of the second layer  26 . 
     The first and second side edges  28 ,  30  of the first folded sheet  12  are heat sealed to define an interior compartment  32  between the first and second overlapping layers  24 ,  26  of the first sheet  12  and an opening  33  to the interior compartment  32  at the free edge  34  of the second layer  26 . The first sheet  12  of polymeric material is perforated near the second folded edge  36  to define a first removable receipt  48 . The first sheet  12  of polymeric material is perforated near the edge  38  of the flap  20  to define a second removable receipt  50 . An aperture  40  is formed through the folds of the first layer  24  of the first sheet  12  and through the second sheet  14  sandwiched between the folds of the first sheet  12 , at a distance of at least three inches from the perforation defining the first removable receipt  48 . The first and second sheets  12 ,  14  are heat sealed around the perimeter of the aperture  40  and at locations  42 ,  44  above and below the aperture  40 . 
     Indicia  54  may be printed on any portion of the plastic bag  10  either before or after formation of the bag  10 . In an exemplary embodiment, ink  60  is applied to portions of the first sheet  12  near the side edges  28 ,  30  and the opening  33  formed by the free edge  34  of the second layer  26  of the first sheet  12 . The ink  60  applied in these areas prevents the flap portion  20  of the bag  10  from sealing against the bag  10  when the bag  10  is machined. 
     While the present invention has been illustrated by the description of the various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in anyway limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of applicant&#39;s general inventive concept.