Abstract:
The present invention provides a single wrap container and a method for forming such a container and a blank therefor. The blank and, hence, the container are formed of a multilayer web that has an inner liner ply and an outer label ply, each adhered to opposite sides of a paper ply, which can be recycled paper. The multilayer web is cut to a predetermined shape, for example, using a rotary die, thereby forming the blank. The container can then be formed by singly wrapping the blank so that helical wrapping is not required and a seam formed by joining the edges of the blank is linear.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1) Field of the Invention  
         [0002]     This invention relates to a container having a multilayer sidewall that is singly wrapped and a method for forming such a container.  
         [0003]     2) Description of Related Art  
         [0004]     A variety of multilayer structures are conventionally used for forming containers. Such structures can include layers formed of paper, polymers, metallic foils, and the like, depending on the intended use of the container. For example, interior liners can be formed of moisture and gas barrier materials, such as plastics and metals, for containers used for food products.  
         [0005]     According to one conventional method of forming containers, the multiple plies of the multilayer structure are wound helically on a cylindrical mandrel, with the plies overlapping so that a continuous cylindrical tube is formed. As the plies are disposed on the mandrel, glue is provided between the plies, and the tube is compressed radially inward on the mandrel so that the plies are adhered. The plies can be continuously disposed on the mandrel as the formed tube is slid axially along the mandrel, and the tube is then cut, either on or off the mandrel, to form short cylindrical tube sections. The ends of each tube section can be closed, for example, by gluing or frictionally fitting a round cap to each end. The structure of the container is determined by the type and order of the plies that are disposed on the mandrel. The size is determined by the diameter of the mandrel and the interval between the cuts. However, non-cylindrical shapes can be difficult or impossible to form with such a method, especially shapes with non-uniform cross sections. Further, the helical seam extending around the resulting container can detract from the aesthetic appeal of the container, and can complicate pre-printing of the outer surface of the outer ply of the container.  
         [0006]     Thus, there exists a need for an improved container and a method for forming the container. Preferably, the container should be formed of a multilayer structure that provides a moisture and/or gas barrier and can be formed at least partially of recycled materials such as recycled paper. The method should not require helical wrapping, and the resulting container should not have a helical seam. Further, the method should be useful for forming containers of varying shapes, including non-cylindrical shapes and shapes with non-uniform cross sections. Finally, the method should be compatible with pre-printed label materials to provide a container that is aesthetically appealing  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a single wrap container and a method for forming such a container and blanks therefor. The container is formed from a multilayer web having liner and label plies adhered on opposite sides of a paper ply. The multilayer web is cut with a die. The resulting die cut blank can be substantially flat and configured to be wrapped, or bent, to form the single wrap container.  
         [0008]     According to one embodiment of the present invention, the paper ply can be recycled paper, which can be covered on either side by the liner and printed label plies. The multilayer web can be conditioned, for example with heat and pressure, and then cut with the die or first coiled into a roll. The label can be printed before or after being adhered to the paper ply.  
         [0009]     The blank can also be bent to form a container, such as for food packaging. For example, the blank can be bent about 360 degrees, and first and second edges of the blank can be joined to form a linear interface. The first and second edges of the blank can be nonparallel so that the resulting container defines a space that is at least partially conical. At least one end of the container can be closed with an end member.  
         [0010]     Thus, the container can be formed of a multilayer web sidewall that extends circumferentially between first and second edges joined at a seam. The sidewall has a paper ply with a liner ply adhered to the inner side and a label ply adhered to the outer side. The liner and label plies can be formed of polymers, and the label ply can be opaque and can have indicia on an outer surface. Thus, the multilayer web can include recycled paper while providing a moisture and/or gas barrier. Further, the label ply can be preprinted and can substantially cover the outer surface of the paper ply to provide aesthetic appeal for the container. In addition, the blanks can be singly wrapped to form containers of various sizes and shapes with substantially linear, i.e., non-helical, seams.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0011]     Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:  
         [0012]      FIG. 1  is an elevation view of an apparatus for forming a container according to one embodiment of the present invention;  
         [0013]      FIG. 2  is a plan view of the apparatus of  FIG. 1 ;  
         [0014]      FIG. 3  is a plan view of a blank formed according to one embodiment of the present invention; and  
         [0015]      FIG. 4  is a perspective view of a container formed from the blank of  FIG. 3  according to one embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.  
         [0017]     Referring now to the figures and, in particular,  FIGS. 1 and 2 , there is shown an apparatus  10  for forming blanks  100  and containers  110 , such as can be used for food packaging, according to one embodiment of the present invention. The illustrated apparatus  10  can be used to continuously adhere liner and label plies  70 ,  80  to a paper ply  60 , condition the resulting multilayer web  90 , cut the multilayer web  90  to form blanks  100 , and configure the blanks  100  into containers  110 . In other embodiments, however, the multilayer web  90  or the blanks  100  can be stored and used to form the containers  110  at a location or time other than immediately subsequent to the formation of the multilayer web  90 . For example, the multilayer web  90  can be formed and wound in rolls or coils, or the blanks  100  can be cut and stacked or otherwise stored.  
         [0018]     The paper, liner, and label plies  60 ,  70 ,  80  can be provided as rolls of material, as shown in  FIG. 1 . The particular material used for each ply  60 ,  70 ,  80  can vary and can be determined according to the intended contents and environment of the container  110 , weight and strength requirements, printing or other aesthetic requirements, the cost and availability of materials, and the like. For example, the paper ply  60  can be paperboard that is formed partially or entirely of recycled paper. The liner ply  70  can be formed of a moisture resistant layer, which can also act as a gas barrier. For example, the liner  70  can be a lamination of polyethylene, aluminum foil, polyethylene, and Kraft paper. The Kraft paper, which can be extensible Kraft, is disposed against the paper ply  60 , and the first polyethylene layer is directed away from the paper layer  60 . The label ply  80  can be formed of paper, polymers, foil plies, and the like. For example, the label  80  can be formed of 40 pound clay-coated one-side (C1S) Kraft paper, with the clay-coated side directed away from the paper ply  60 .  
         [0019]     In one embodiment, the label  80  is a substantially opaque ply so that the color or other visual characteristics of the paper ply  60  are not readily visually apparent by viewing the outside of the container  110 . For example, the paper ply  60  can be formed of brown recycled paper, and the label ply  80  can cover the paper ply  60  so that the appearance of the container  110  is not affected, or only marginally affected, by the paper ply  60 . The label ply  80  can be printed or otherwise provided with indicia  82  such as graphics or text for purposes of identifying the contents of the container  110 , improving the aesthetic appearance of the container  110 , and the like. If the label ply  80  is opaque, an outer surface of the label ply  80  can be printed. Further, the label ply  80  can be printed before, after, or during the forming of the container  110 . For example, the label ply  80  can be printed before being adhered to the paper ply  60 , after the blank  100  has been formed, or after the container  110  has been formed from the blank  100 . Various methods can be used to print the label  80 , as are known in the art. In addition, the label ply  80  can be printed in a width larger than that used in the apparatus  10  and then cut to the desired width before being adhered to the paper ply  60 .  
         [0020]     The liner and label plies  70 ,  80  are adhered to the paper ply  60 , for example, by applying an adhesive to one or more of the plies  60 ,  70 ,  80  so that the adhesive is disposed between the paper and liner plies  60 ,  70  and between the paper and label plies  60 ,  80 . As shown in  FIG. 1 , the adhesive can be applied by adhesive applicators  12 ,  14  to a first side of the paper ply  60  that is directed toward the liner ply  70  and to a side of the label ply  80  that is directed toward the paper ply  60 . Alternatively, the adhesive can be applied to both sides of the paper ply  60  or to a side of the liner ply  70  that is directed toward the paper ply  60 . With the adhesive disposed between the plies  60 ,  70 ,  80 , the resulting multilayer web  90  can be passed through a nip  16  defined by two rollers  18   a ,  18   b . The rollers  18   a ,  18   b  can be configured to apply a compressive force on the plies  60 ,  70 ,  80  so that the adhesive is disposed evenly and the multilayer web  90  is substantially uniform in thickness. Alternatively, the liner and label plies  70 ,  80  can be adhered to the paper ply  60  by other methods, for example, by heating the plies  70 ,  80  and laminating the plies  70 ,  80  on the paper ply  60  with a pre-applied thermoplastic polymer that bonds the plies  70 ,  80  to the paper ply  60 .  
         [0021]     The multilayer web  90  then proceeds to a conditioning unit  20 , where the web  90  is heated or otherwise processed to promote uniform drying of the adhesive. The conditioning unit  20  can be a conventional oven, with convection air flow, through which the multilayer web  90  can be passed continuously. The multilayer web  90  may be passed through another nip defined by rollers  22   a ,  22   b  to further consolidate and make uniform the web  90 . Additional rollers (not shown) can also be provided in the conditioning unit  20 . Further, the conditioning unit  20  can spray water or otherwise introduce moisture to the web  90 . Thus, the conditioning unit  20  can be used to adjust a moisture content of the web  90  to a predetermined moisture level, thereby affecting the stiffness and pliability of the web  90 .  
         [0022]     The multilayer web  90  is cut to form the blanks  100 , i.e., pieces of the multilayer web  90  having a predefined shape, each of which can be configured to form one of the containers  110 . The multilayer web  90  can be cut shortly after and continuously with the conditioning, as shown in  FIGS. 1 and 2 . Alternatively, the multilayer web  90  can be wound to form rolls of material that can be cut at another time and/or using a machine that is located remotely from the adhering and conditioning devices  12 ,  14 ,  20 . According to one advantageous embodiment of the present invention, a rotary die  30  is configured to cut the multilayer web  90  to form the blanks  100 . The rotary die  30  can include opposed rollers  32 ,  34  that define a nip  36  therebetween, and at least one of the rollers  32  can define an outer cutting surface  38  that defines a cutting feature  40 , such as a raised portion that corresponds in shape to the blank  100 . The other roller  34  can define a correspondingly opposed cutting feature (not shown) that contacts or receives the cutting feature  40  of the first roller  34 . The rollers  32 ,  34  are rotated as the multilayer web  90  is passed therebetween such that the multilayer web  90  is urged against the outer cutting surface  38 , the cutting feature  40  is impressed into or through the multilayer web  90 , and the web  90  is thereby cut to the desired shape of the blank  100 . The rotary die  30  can be used to cut the multilayer web  90  into the blanks  100  as the web  90  is passed continuously through the die  30 . Alternatively, other cutting devices can also be used for cutting the web  90 . For example, the blanks  100  can be cut using reciprocating dies, punches, flying blades or saws, and the like. Further, the cutting device can be integral to one of the other components of the apparatus  10 . For example, the cutting device can be integral to a wrapping device  50 , described further below, so that the multilayer web  90  can be formed and delivered directly to the wrapping device  50 , where a reciprocating die (not shown) cuts the web  90  to the desired dimensions.  
         [0023]     The multilayer web  90  can be formed to have a width that is only slightly larger than a width of each blank  100 . Such a “single line” narrow web can be cut with a rotary die inline with the forming process and fed to the wrapping device  50 , or the web  90  can be fed directly into a wrapping device that is equipped to cut the blanks  100  from the web  90 . Alternatively, the width of the multilayer web  90  can be greater than the width of the blanks  100  so that multiple blanks  100  can be cut from the width of the web  90 . For example, two blanks  100  can be cut from the width of the web  90 , as shown in  FIG. 2 . The blanks  100  can be fed directly into the wrapping device  50  or taken offline and fed to the wrapping device  50  at a later time. In any case, the rotary die  30  or other cutting device can be configured to minimize the amount of excess or scrap material  42 . For example, each of the two blanks  100  simultaneously cut by the rotary die  30  shown in  FIG. 2  is oriented oppositely relative to the other blank  100 .  
         [0024]     Each blank  100  can be cut completely from the multilayer web  90  and the excess material  42  from the multilayer web  90  can be removed and deposited in a receptacle  44  for recycling or disposal. The resulting blanks  100 , which can be substantially flat, are deposited onto a conveying device  46  such as a continuous conveyor belt. The conveying device  46  can deliver the blanks  100  directly to a wrapping device  50 , as shown in  FIGS. 1 and 2 . Alternatively, the blanks  100  can be stacked and stored for subsequent use in a wrapping device remote to the forming apparatus  10 . Additionally, features can be provided on the blanks, for example, by folding or rolling the edges, depositing coatings or additional layers of material on the blanks, printing the blanks, and the like.  
         [0025]     The blanks  100  shown in  FIG. 3  are substantially flat and extend between first and second converging edges  102 ,  104 . Transverse ends  106 ,  108  of the blanks  100  are curved. Thus, the illustrated blanks  100  can be bent, i.e., wrapped, folded, or otherwise configured to form a sidewall  112  of a container  110  that is at least partially conical and defines an interior space  114 . By the term “at least partially conical,” it is meant that a portion of the container  110  defines at least part of a cone, e.g., a frustocone. In one advantageous embodiment of the present invention, the blanks  100  are bent about 360 degrees to form the single wrap container  110 , i.e., the first edge of the blank  100  is bent about 360 degrees to form a sidewall  112  of a tubular shape that defines an inner space  114  therein. For example, the first edge  102  can be joined to the second edge  104  by heat sealing or otherwise adhering the two edges  102 ,  104  to form a seam  118  that extends substantially linearly along the container  110 . The tubular shaped sidewall  112  can be conical or frustoconical to define a circular cross section, or the sidewall  112  can have a cross section that defines a shape of another polygon, for example, a square, rectangle, triangle, and the like. Further, the sidewall  112  can define one or two open ends, which can be closed by attaching an end member, such as a bottom member  116  or a cap, to one or both of the open ends. For example, the blanks  100  can be used to form the frustoconical sidewall  112  of the container  110  shown in  FIG. 4 , such that the container  110  can receive part of a similar container for stacking. Alternatively, the blanks  100  can be bent to form containers  110  of other configurations, having uniform or nonuniform cross sections.  
         [0026]     The wrapping device  50  is configured to bend the blanks  100  to form the containers  110 . For example, the wrapping device  50  can fold the blanks  100 , wind the blanks  100  around a mandrel, or otherwise bend the blanks  100 . Various devices can be used for forming the container  110 . For example, the wrapping device  50  can be a single wrap package forming machine such as the BMP 200 Paper Cup Machine made by Michael Hörauf Maschinenfabrik GmBH &amp; Co. KG of Donzdorf, Germany, which can be used to bend each blank  100 , seal the edges  102 ,  104 , and attach the bottom member  116  thereto. Further, the wrapping device  50  can be configured to cut the blanks  100  from the web  90  so that the web  90  can be fed directly from the conditioning device  20  to the wrapping device  50 , i.e., without being first cut in a rotary die  30  or other cutting device.  
         [0027]     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.