Patent Publication Number: US-2007104398-A1

Title: Container With Peelable Seal Assembly and Method of Making

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/735,452 for a FLEXIBLE BAG WITH PEELABLE SEAL ASSEMBLY AND METHOD OF MAKING, filed on Nov. 10, 2005, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      A container, particularly a flexible bag with a peelable seal assembly and a method of making the same as disclosed herein.  
      2. Description of the Prior Art  
      Traditionally, containers and more particularly flexible bags are formed from a liner with a first side and a second side folded over the first side. The sides of the bag are heat sealed together to create a seal to enclose and seal contents within the bag. Such flexible bags are used for storing contents for a variety of goods such as for example food products and more specifically ready to eat breakfast cereals packages for crackers, cookies, candies, baking goods etc. The user pulls on the sides along the seal to break the seal and to access the contents of the bag. Generally the seals of the bag are difficult to break and the seals may have more integrity than the sides of the bag thereby requiring the user to tear the sides of the bag to access the contents of the bag.  
      It is known in the art to coextrude a peelable adhesive with the liner such that, when the second side is folded over the first side, the peelable adhesive faces itself. Therefore, when the seals are formed, the peelable adhesive of the first side adheres to the peelable adhesive of the second side. The peelable adhesive reduces the effort required to open the bag along the seals. The thickness of the peelable adhesive has an affect on the effort required to break the seal. However, the coextrusion of the peelable adhesive with the liner is difficult to control thereby making it difficult to consistently create bags with the same low opening effort. Additionally, the heat sealing process varies and it can be difficult to create identical seals on consecutive bags. In other words, it is difficult to maintain low tolerances in the process of heat sealing and the seals created by the process may have varying opening efforts. Therefore, the manufacturer of the bag must err on the side of higher opening efforts to eliminate the possibility of inadvertent openings along the seals.  
      In addition, the sides of the liner are thin and flexible and are therefore difficult to grasp to tear the seals. In addition, after the seal has been broken, the thin and flexible bag is wrinkled in the area of the seal and contents of the bag are trapped in the wrinkles when the contents of the bag are poured out of the bag. Therefore, as the contents of the bag are poured out of the bag the contents may get caught in the wrinkles thereby making it difficult to neatly pour the contents out of the bag. Additionally, if contents remain in the bag after the seal has been broken, the bag must be folded or a clip must be clipped onto the bag along the seal to keep the contents of the bag sealed within the bag.  
      It is desirable to manufacture a container, such as for example a flexible bag that is heat sealed together along a seal and is easily opened along the seal. Likewise, it is desirable to manufacture a bag that is easily grasped to pull the bag open along the seal and a method of making the same. It is also desirable to manufacture a flexible bag that does not have wrinkles along the seal to allow the contents of the bag to be neatly poured from the bag. It is also desirable to manufacture a bag that has a pre-defined pour spout that facilitates to pouring of the contents from the bag. Additionally, it is desirable to manufacture a bag that can be resealed along the seal to store the contents for later use.  
     SUMMARY OF THE INVENTION AND ADVANTAGES  
      The current invention is a container and in the preferred embodiment a flexible bag with a seal assembly. The bag includes a first side and a second side folded over the first side. The sides are heat sealed together along seals. The seal assembly is disposed in the seal and includes a first tab, a second tab, a middle layer of peelable adhesive sandwiched between the first tab and the second tab, a first outside layer of adhesive that more securely adheres or more permanently adheres to the first side of the bag, and a second outside layer of adhesive that is compatible with the second side of the bag such that second outside layer is heat sealed to the liner and as with the first outside layer of adhesive to more securely adhere the second tab to the liner. The first tab and the second tab are easily grasped and may be pulled in opposite directions to break the middle layer of peelable adhesive. The middle layer is heat resistant such that the first tab and the second tab do not melt together during the formation of the seal. A resealable peelable adhesive may also be disposed between the first tab and the second tab. The tabs may also be brightly colored or printed upon.  
      Accordingly, the tabs are easily grasped and the thickness of the middle layer of peelable adhesive may be easily controlled such that variation in the effort to open various bags is eliminated and the effort required to peel the tabs apart may be controlled at a low effort. Likewise, the bright color or printing on the tabs alerts the user to the easily opened area. Also, the tabs reinforce the flexible liner and act as a pour spout when the contents of the bag are poured out of the bag. Additionally, the resealable peelable adhesive allows the user to reseal the bag along the seal to preserve the freshness of the contents of the bag.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other advantages of the present invention will be readily appreciated, as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:  
       FIG. 1  is a perspective view of a flexible bag with a seal assembly;  
       FIG. 2   a  is a front view of the flexible bag with a seal assembly wherein the seal assembly extends across an entire length of a seal;  
       FIG. 2   b  is a front view of the flexible bag with the seal assembly wherein the seal assembly extends across a portion of the seal;  
       FIG. 3   a  is a cross-sectional view of the bag wherein the liner of the bag includes a first layer and a second layer;  
       FIG. 3   b  is a cross-sectional view of the bag wherein the liner of the bag has a single layer;  
       FIG. 3   c  is a cross-sectional view of the bag wherein the seal assembly includes a re-sealable peelable adhesive;  
       FIG. 3   d  is a cross-sectional view of the bag wherein the seal assembly includes a snap fastener; and  
       FIG. 4  is a perspective view of a bagger assembly.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a flexible bag  20  with a peelable seal assembly  22  is shown.  
      The bag  20  is formed from a liner  24  which includes a first layer  26  and a second layer  28  coextruded with the first layer  26  (See  FIGS. 1 and 3   a ). The first layer  26  is preferably high density polyethylene. The second layer  28  is a peelable adhesive, and is more preferably low density polyethylene with polybutylene. It will be understood by those of ordinary skill in the art that a peelable adhesive is an adhesive that has less adhesive strength allowing it to be peeled apart or opened. An example of a peelable adhesive is the use of an adhesive layer that has an additive mixed into the adhesive layer to lower the adhesive strength. Those of ordinary skill in the art commonly refer to this additive as a contaminant. The liner  24  is folded to define a first side  30  and a second side  32  such that the second layer  28  of the liner  24  faces itself and the first layer  26  of the liner  24  faces outwardly. The first side  30  and the second side  32  of the bag  20  are heat sealed together along a top seal  34 , a bottom seal  36  (see  FIG. 2   a ), and a side seal  38 . When heat is applied to create the seals  34 ,  36 ,  38 , the second layer  28  of the first side  30  and the second layer  28  of the second side  32  melt and adhere to one another to create the seals  34 ,  36 ,  38  upon cooling. Contents may be added to the bag  20  prior to the formation of any of the seals  34 ,  36 ,  38 . The contents may be any products such as for example, food items like cookies, crackers, candy, baking goods, etc. One particular use of the present invention is for packaging ready-to-eat breakfast cereal.  
      The seal assembly  22  is disposed between the first side  30  and the second side  32  of the bag  20  and is more specifically sealed along the top seal  34 , (see  FIGS. 1, 2   a  and  3   a ).  
      The peelable seal assembly  22  includes a first tab  40 , a second tab  42  facing the first tab  40 , a middle layer  44  sandwiched between the first tab  40  and the second tab  42 , a first outside layer  46  disposed on the first tab  40  opposite the middle layer  44 , and a second outside layer  48  disposed on the second tab  42  opposite the middle layer  44 . In the disclosed embodiment, the middle layer  44  extends along an entire length of the first tab  40  and the second tab  42 , but it will be appreciated by those of ordinary skill in the art that the middle layer  44  could be shorter than the tabs  40  and  42  or spaced at intervals along the length of the tabs  40  and  42 . The first tab  40  and the second tab  42  are wider than the middle layer  44  such that the first tab  40  presents a first extension  70  extending beyond the middle layer  44  and the second tab  42  presents a second extension  72  extending beyond the middle layer  44 .  
      In the disclosed embodiment, the first tab  40  and the second tab  42  are made of the same material and the material may be for example, polyethylene, polypropylene, or polyester. The middle layer  44  is a peelable adhesive that is preferably a resin blend. More specifically, the resin blend may include Surlyn® which is manufactured by DuPont. Alternatively, the resin blend may include low density polyethylene or other materials designed to achieve the results intended by the present invention. The middle layer  44  is heat resistant such that the middle layer  44  does not allow the tabs  40 ,  42  to weld together during the application of heat for forming the top seal  34 . The first outside layer  46  is a peelable adhesive that more permanently adheres to the second layer  28  of the liner  24  when applied to the second layer  28 . Preferably the first outside layer  46  is a vinyl based adhesive. The second outside layer  48  is an adhesive that is compatible with the second layer  28  of the liner  24  to more permanently seal to the liner  24  during the formation of the top seal  34 . The second outside layer  48  is preferably low density polyethylene.  
      When the seal assembly  22  is heat sealed into the top seal  34 , the first outside layer  46 , the second outside layer  48 , the first tab  40 , and the second tab  42  may melt to adhere to the liner  24 . However, the middle layer  44  extends between the first tab  40  and the second tab  42  and because the middle layer  44  is heat resistant, the first tab  40  and the second tab  42  do not adhere to each other.  
      The user grasps the first extension  70  of the first tab  40  and the second extension  72  of the second tab  42  and pulls the tabs  40 ,  42  in opposite directions to separate the tabs  40 ,  42 . More specifically, when the user pulls the tabs  40 ,  42  in opposite directions, the integrity of the middle layer  44  is compromised and the tabs  40 ,  42  separate. The first tab  40  and the second tab  42  may be brightly colored or may be printed upon such that it is evident that the first tab  40  and the second tab  42  may be grasped and pulled apart to access the contents of the bag  20 .  
      The bonding strength of the middle layer  44  between the first tab  40  and the second tab  42  is easily controlled and is not affected by the heat sealing process such that the effort to separate the tabs  40 ,  42  and therefore the effort to open the bag  20  is consistent. Additionally, in the disclosed embodiment, the tabs  40 ,  42  are stiffer than the liner  24  and reinforce the liner  24  such that, after the bag  20  has been opened along the top seal  34 , the tabs  40 ,  42  act as a pour spout and such that the contents of the bag  20  do not become lodged in wrinkles in the liner  24  as the contents are poured from the bag  20 .  
      As shown in  FIG. 2   a , the seal assembly  22  may be disposed along an entire length of the top seal  34 . Alternatively, as shown in  FIG. 2   b , the seal assembly  22  may be disposed along a portion of the top seal  34 . If the seal assembly  22  is disposed along a portion of the top seal  24 , after the user has separated the tabs  40 ,  42 , the user continues to pull the tabs  40 ,  42  in opposite directions such that the second layer  28  of the liner  24  easily separates from itself along the top seal  34 .  
      Additionally, as seen in  FIG. 3   c , a re-sealable peelable adhesive  66  may be disposed between the first tab layer  40  and the second tab layer  42 . Preferably, the resealable peelable adhesive  66  is disposed on the seal assembly  22  extending along the entire length of the top seal  34  such that the seal assembly  22  may be resealed along the entire length of the top seal  34  to preserve the freshness of the contents of the bag  20 . Preferably, the resealable peelable adhesive is a water and solvent based adhesive.  
      Additionally, as seen in  FIG. 3   d , an elongated snap fastener  68  may be disposed between the first outside layer  46  and the second outside layer  48  of the seal assembly  22 . The snap fastener  68  includes an elongated male portion and a complimentary elongated female portion wherein the female portion receives and engages the male portion to seal the female portion and the male portion together.  
      Alternatively, as shown in  FIG. 3   b , the liner  24  may be a single layer  50  that is preferably high density polyethylene. In such an embodiment, the first outside layer  46  of the seal assembly  22  is a peelable adhesive that more permanently adheres to the single layer  50  of the liner  24  when applied to the single layer  50 . Likewise, the second outside layer  48  of the seal assembly  22  is an adhesive that is compatible with the single layer  50  of the liner  24  to more permanently seal to the single layer  50  during the formation of the top seal  34 . In such an embodiment, the single layer  50  would be heat sealed to itself along the top seal  34  and the bag  20  would only be opened along the seal assembly  22 .  
      As shown in  FIG. 4 , the bag  20  is formed on a bagger assembly  52 . The bagger assembly  52  includes a backstand  54 , a labeler  56  disposed on the backstand  54 , a filler tube  58  that is generally cylindrically shaped and extends generally vertically, vertical heat seal jaws  60  extending along the filler tube  58 , and horizontal heat seal jaws  62  are disposed below the filler tube  58 . If the liner  24  includes the first layer  26  and the second layer  28 , the liner  24  is oriented flatly along the backstand  54  with the second layer  28  of the liner  24  facing upwardly away from the backstand  54 .  
      The method of forming the bag  20  includes continuously feeding the liner  24  along the backstand  54  to the filler tube  58 . The liner  24  is fed along the backstand  54  below the labeler  56 .  
      The method further includes facing the first outside layer  46  of the seal assembly  22  toward the liner  24  on the backstand  54  and adhering the first outside layer  46  to the liner  24 . More specifically, the labeler  56  orientates the seal assembly  22  such that the first outside layer  46  faces the liner  24 . The labeler  56  also dispenses the seal assembly  22  onto the liner  24  such that the first outside layer  46  adheres to the liner  24 .  
      The method further includes continuously feeding the liner  24  around the filler tube  58  and overlapping opposite ends  64  of the liner  24  between the vertical heat seal jaws  60 . As the liner  24  is fed from the backstand  54  to the filler tube  58  the liner  24  conforms to the cylindrical shape of the filler tube  58  and the opposite ends  64  of the liner  24  are overlapped. If the liner  24  includes the first layer  26  and the second layer  28 , the liner  24  is orientated such that the second layer  28  faces inwardly toward the cylinder and the second layer  28  is facing itself along the opposite ends  64  of the liner  24 .  
      The method further includes forming the side seal  38  of the bag  20  by closing the vertical heat seal jaws  60  to seal the opposite ends  64  of the liner  24  together.  
      The method further includes forming the top seal  34  and the bottom seal  36  of consecutive bags  20  by closing the horizontal heat seal jaws  62  to seal the liner  24  together and cutting the consecutive bags  20  apart between the seals  34 ,  36 .  
      The method further includes feeding the contents of the bag  20  through the filler tube  58  to fill the contents into the bag  20 .  
      The method further includes timing the step of adhering the first outside layer  46  of the seal assembly  22  to the liner  24  such that the seal assembly  22  is adhered to liner  24  in register with the horizontal seal jaws  62  such that the seal assembly  22  is disposed between the horizontal seal jaws  62  when the liner  24  is advanced and the seal jaws  62  are closed. More specifically, the bagger includes an end coder that records the length of liner  24  that has passed through bagger and the labeler  56  communicates mechanically or electrically with the end coder to adhere the seal assembly  22  in register with the seal jaws  62 .  
      The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings, and  
      the invention may be practiced otherwise than as specifically described.