Patent Publication Number: US-2009238498-A1

Title: Compaction Package

Description:
FIELD OF THE INVENTION 
     The present invention relates to packaging for granular materials and more particularly to the use of heat shrink film portions in packing to exclude or limit oxygen from the package and to avoid attrition of packaged granular material during shipping and storage. 
     DESCRIPTION OF RELATED ART 
     Vacuum packaging technology is well known in the art. For example, in the food, detergent, coffee, and industrial material packaging arts, semi-rigid packages are used to contain material while a vacuum is drawn on the packaging. While under vacuum, the package is sealed. In this process, air, containing oxygen, is removed from the container to maintain freshness in the product during transport and storage before sale of the product to a consumer. Further, the vacuum package tends to compact granular materials contained in the package as a vacuum is drawn thus providing more efficient packages for these types of material. Attrition of granular material is also limited because individual grains of material are constrained from movement relative to other particles in the vacuum package. 
     A description of vacuum packaging of ground coffee is contained in U.S. Pat. No. 4,957,753. U.S. Pat. No. 5,598,684 discloses a vacuum package, and a method and apparatus for making vacuum packages filled with granular material. As noted, when a vacuum type package is used to package granular material such as ground coffee, attrition of the granular material is typically less than material attrition in loose-pack type packages since the granular material is limited in movement when compacted by a vacuum package. However, commercial vacuum packaging generally requires expensive vacuum generation equipment and complicates the overall design of a packaging line. Further, conventional vacuum packaging is venerable to punctures and leaks in the package that degrades package performance. 
     Shrink packaging is a more recent packaging development that avoids some of the shortcomings of vacuum packaging. Further, for granular material shrink packaging offers certain advantages over vacuum packing while still providing much of its oxygen excluding, packaging efficiency, and attrition minimizing benefits. Still further, shrink packaging has a faster packing rate (units/minute) than vacuum packaging. For example, U.S. Pat. No. 6,945,015 discloses a shrink wrap transportable container and methods. The invention provides a package diameter reducing system for reducing the diameter of a flexible cylindrical container as the container is filled. The system relies on a package that comprises material that shrinks when heated to a certain critical heat shrink temperature. The system includes a heat generating shrinking device to shrink the container at the fill level as the container is filled with a plurality of particles. The shrinking device can include a heater to supply direct heat at the fill level. Shrinking of the container at the fill level tends to evacuate oxygen-containing air as the container fills and limits granular product attrition through supporting engagement between granular particles. 
     In prior art shrink packaging, a package was first formed from heat shrink film portion such as polyolefin, polyvinyl chloride (PVC), or polyethylene terephthalate glycol (PETG) shrink film. As is well known by those of ordinary skill in the art, such heat shrink film portions contract when exposed to a heat source that raises the package temperature above a certain critical temperature. A process of heat treating a biaxially oriented film of polyolefin, thermoplastic, crystallizable polymeric material and the like provides the heat activated shrink properties to the shrink film. Depending on how the film is processed, shrinkage rates may be independently controlled in both a transverse direction across the film and in a longitudinal direction along the film perpendicular to the film transverse direction. 
     A distinguishing characteristic of biaxially oriented packaging film is its capacity, upon exposure to some level of heat, to shrink or, if restrained, to create shrink tension within the film. Typically, heat shrink film portions also have excellent heat seal properties at low temperatures, sliding properties over a wide range of temperatures and releasing properties from a hot plate, all of which are desirable for packaging articles by the use of automatic packaging machines. 
     In a typical method of heat shrink packaging, shrink film is first formed into a tube by, for example, extrusion. The tube may then be made into individual bags into which the item to be packaged is placed, then sealed at one or both ends, either thermally or with some sort of closure device. Shrink film, for instance, is used for packaging food in this way. However, a major thrust in bag type packaging is the formation of bags from a continuous roll of film sheet rather than from pre-extruded tube, where the items to be packaged may often be disposed in a tray. Here, bags are formed continuously around the item or trayed items. This is achieved by first forming the sheet into a continuous tube, around continuously supplied items or trays by continuously sealing the film edges together, longitudinally, below the item or tray, and then sealing (or cutting then sealing) the tube in the direction transverse to the direction of the moving tube and trays, into individual bags. The tube is generally formed horizontally, around the continuously fed items or trays. The items or trays in the tube are moved along, with the tube, by a horizontal conveyor. The direction in which the film, the tube formed from the film, and the item or trays travel is commonly referred to as the “machine” direction or longitudinal direction. The direction of the sealing and cutting of the formed tube between each tray is commonly referred to as the “cross” transverse direction. 
     The general mode of continuous operation, film sheet-to-tube-to-bag, is common to many continuous packaging machines, using different type of film. However, not only are there differences in how the tube is formed, but there are major differences in the type of seal, and in how the longitudinal and transverse seals are made. There is then the question of if and how the formed bag is then operated on to finish the packaging operation. Since the method of sealing and the type of seal varies, the nature of the resulting bag will vary. Typically, it will depend on the type of film—hard, stretch or shrink. Three common forms of seal are the ‘fin’-seal where the film sheet is pressed together to form a fin, the ‘bead’-seal, where film is pressed together, melts and forms a bead or beads (sometimes referred to as welding), and an “overwrap” seal, where cut ends are pressed around the item or trayed items and sealed. Fin-seals may also be subsequently overwrapped. 
     A continuous packaging machine of the above described general mode of operation, i.e. sheet-to-tube-to-bag, is described in U.S. Pat. No. 5,125,216. In this particular case, the disclosure appears to describe formation of a loose bag from hard film, and the item is not necessarily in a tray. It uses fin type seals both in the longitudinal and transverse direction. Fin-seals are generally not particularly tight seals, and are generally not suitable for packaging moisture containing items. 
     A major disadvantage of containing products and, more particularly, granular material products in a package made up of shrink film is the cost of heat shrink film portion material itself when compared to the cost of conventional flexible packaging film. 
     SUMMARY OF THE INVENTION 
     The present invention provides an inexpensive, cost-effective compaction package adapted for use with granular materials. The compaction package of the present invention uses considerably less expensive heat shrink film material than does a prior art package made completely of heat shrink film. 
     The package is a composite package that includes a flexible film portion and a heat shrink film portion coupled to the flexible film portion. An opening at the top of the compaction package provides a means to fill a volume defined by the package with a granular material prior to exposure of the package to a heat source capable of activating the heat shrink film portion of the compaction package. When the compaction package is exposed to a heat source sufficient to activate the heat shrink film portion of the compaction package, the heat shrink film portion of the compaction package shrinks and reduces the volume of the compaction package thereby compacting the granular material contained within the compaction package. 
     The heat shrink film portion of the package is coupled to the flexible film portion of the compaction package at one or more considered positions of the compaction package. When exposed to a heat source of sufficient intensity to activate the heat shrink film portion, the compaction package according to the present invention provides shrinkage in the volume of the interior space of the package that substantially achieves the volume shrinkage provided by a prior art compaction package made up entirely of heat shrink film portion material. Since only a portion of the compaction package is formed from expensive heat shrink film the compaction package of the present invention is less costly than prior art shrink film packages formed entirely from shrink film. 
     Compaction of contained product protects the product from degrading during transport/distribution due to attrition and abrasion. This is especially true for brittle granular products that undergo shock and vibration such as, for example, cat litter. The compaction packaging of the present invention is adaptable to many conventional flexible packaging lines, because it requires only the addition of a heating tunnel. 
     In one embodiment, the flexible film portion of the compaction package defines an open top container having a bottom and a perimeter wall coupled to the peripheral edge of the bottom. Four upright walls coupled at their respective side edges form the perimeter wall. The compaction may be integrally formed by means well known to those of ordinary skill in the art by, for example, blow film forming, or other well-known means. 
     In this embodiment, a strip of heat shrink film portion is coupled to and overlies part of one or more of the upright walls of flexible film portion of the compaction package. The heat shrink film portion is biased to shrink in only the transverse direction across the film when exposed to a heat source of sufficient intensity. In another embodiment, the heat shrink film portion is bias to shrink the longitudinal direction. In yet another embodiment, the heat shrink film portion is bias to shrink in both the transverse and the longitudinal directions. 
     In another particularly advantageous embodiment, a strip of heat shrink film is coupled to and overlies part of the flexible film portion of the compaction package at each of the side corner edges of the package where the upright walls intersect. The heat shrink film portion may be biased to shrink in only the transverse direction across the film, only in the longitudinal direction along the length of the compaction package, or in both the transverse and longitudinal directions when exposed to a heat source of sufficient intensity to raise the compaction package above a critical shrink temperature. 
     Thus, provided is a compaction package in accordance with the principle of the present that avoids the limitations of and provides advantages over prior art vacuum compaction packages. Further, provided is a composite shrink-film compaction package that provides cost advantages over prior art shrink film packages and that is particularly adapted to contain granular material such as cat liter, powder detergents, foods such as rice, beans, coffee and the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the drawings wherein like numerals refer to like parts throughout. When considered in conjunction with the subsequent detailed description, a complete understanding of the present invention may be obtained by reference to the accompanying drawings, in which: 
         FIG. 1A  is a perspective view of an embodiment of a filled compaction package in accordance with the principles of the present invention, prior to compaction and having an open top and rectangular bottom; 
         FIG. 1B  is a perspective view of the compaction package of  FIG. 1A  after sealing of the open top and compaction by application of heat; 
         FIG. 1C  is a top sectional view of the compaction package of  FIG. 1A  taken along line  1 C′- 1 C′ of  FIG. 1A   
         FIG. 1D  is a close up view of the area encircled by dotted line in  FIG. 1C  showing a bonding bead coupling a sidewall heat shrink film portion and a sidewall flexible portion of compaction package  100 ; 
         FIG. 1E  is a top sectional view as showing the compaction package of  FIG. 1B  taken along the line  1 E′- 1 E′ after compaction through application of heat; 
         FIG. 2A  is a top sectional view of similar to the view of  FIG. 1C  showing another embodiment of a compaction package in accordance with the principles of the present invention before compaction; 
         FIG. 2B  is a close up view of the area encircled by dotted line in  FIG. 2A  showing a bonding bead coupling sidewall heat shrink film portion and a sidewall flexible portion; 
         FIG. 3  is a perspective view of another embodiment of a filled compaction package in accordance with the principles of the present invention, prior to compaction and having an open top and a rectangular bottom; 
         FIG. 4  is a perspective view of another embodiment of a filled compaction package in accordance with the principles of the present invention, prior to compaction and having an open top and a rectangular bottom; 
         FIG. 5A  is a perspective view of another embodiment of a filled compaction package in accordance with the principles of the present invention, prior to compaction and having an open top and a rectangular bottom; 
         FIG. 5B  is a perspective view of the compaction package of  FIG. 5A  after sealing of the open top and compaction by application of heat; and 
         FIG. 6  is a perspective view of another embodiment of a filled compaction package in accordance with the principles of the present invention having a circular bottom and after compaction by application of heat. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the drawings wherein like numerals refer to like parts throughout. As used herein, positional terms, such as “bottom”, “left” and the like, and directional terms, such as “upward”, “inward” and the like, are employed for ease of description in conjunction with the drawings. None of these terms is meant to indicate that the described part or assembly must have a specific orientation except when specifically set forth. It is also to be understood that the specific elements and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     In one embodiment, a compaction package in accordance with the principles of the present invention includes a flexible plastic film portion and a heat shrink film portion coupled to the flexible film portion. The flexible film portion and the heat shrink film portion of the compaction package together define a flexible container adapted to contain a granular material such as cat-litter. The compaction package includes a bottom, a sidewall coupled to the peripheral edge of the bottom, and an opening at the top of the package. 
     The compaction package is typically filled with a granular material, such as cat litter, through the opening. The compaction package has a first configuration prior to exposure to a heat source capable of raising the temperature of the compaction package above a certain critical temperature. The compaction package has a second configuration after exposure of the filled compaction package to the heat source. The second configuration of the compaction package after exposure to a heat source has a volume that is less than the volume of the first configuration of the compaction package prior to exposure to the heat source. 
     More particularly,  FIG. 1A  is a perspective view of an embodiment of a filled compaction package  100  in accordance with the principles of the present invention, prior to compaction and having an open top  102  and rectangular bottom  103 .  FIG. 1B  is a perspective view of the compaction package of  FIG. 1A  after sealing of the open top and compaction by application of heat.  FIG. 1C  is a top sectional view of the compaction package of  FIG. 1A  taken along line  1 C′- 1 C′ of  FIG. 1A . 
     Referring to  FIGS. 1A ,  1 B, and  1 C together, before application of heat, compaction package  100  is generally configured as a rectangular polyhedron surface defining an open-ended hollow container and having a rectangularly shaped bottom  103  and rectangular upright walls coupled to and projecting from the peripheral side edges of bottom  103 . In one embodiment, compaction package  100  is formed from plastic sheet materials. 
     The rectangular upright walls are coupled to the peripheral side edges of bottom  103  include a front  105  coupled to both a left sidewall  106 L and a right sidewall  106 R ( FIG. 1C ), and a back  108  ( FIG. 1C ) opposite front  105  also coupled to both left and right sidewalls  106 L and  106 R. Bottom  103  and the various peripheral walls define an opening  109  ( FIG. 1A ) and an interior space  110  adapted to contain a material. A shown in  FIG. 1A , a granular material  112  has been placed in interior space  110  through opening  109 . 
     In one embodiment, left sidewall  106 L includes a left sidewall flexible portion  114 L formed of, for example, conventional flexible polymer sheet material such as polyethylene film commonly used in flexible packaging. Coupled to and overlying a part of left sidewall flexible portion  114 L of left sidewall  106 L, is a left sidewall heat shrink film portion  116 L. Similarly, right sidewall  106 R ( FIG. 1C ) includes a right sidewall flexible portion  114 R ( FIG. 1C ) of polyethylene film. Coupled to and overlying a part of right sidewall flexible portion  114 R of right sidewall  106 R, is a right sidewall heat shrink film portion  116 R ( FIG. 1C ). In the embodiment shown in  FIGS. 1A and 1C , left and right sidewall heat shrink film portions  116 L and  116 R are configured as rectangles. Since only a portion of the left and right sidewalls  106 L and  106 R comprises costly heat shrink film portion, the overall cost of compaction package  100  is less than the cost of a prior art compaction package that comprised expensive heat shrink film portion for the entire package. 
     In one embodiment, compaction package  100  includes left and right sidewall heat shrink film portions  116 L and  116 R that are coupled to and overlie a part of left and right sidewall flexible portion  114 L and  114 R by means of adhesive material. In other embodiments, left and right sidewall heat shrink film portions  116 L and  116 R are coupled respectively to left and right sidewall flexible portion  114 L and  114 R by other well-known means such as, for example, heat welding, “fin”-sealing or “bead”-sealing, where the overlapping parts of the film sheets are vigorously pressed together and melted due to frictional heat to form a bonding bead or beads when cooled. 
       FIG. 1D  is a close up view of the area encircled by dotted line in  FIG. 1C  showing a bonding bead  118  coupling right sidewall heat shrink film portion  216 R with right sidewall flexible portion  114 R of compaction package  100 . Referring now to  FIGS. 1C and 1D  together, in one embodiment left and right sidewall heat shrink film portions  116 L and  116 R are coupled to left and right sidewall flexible portions  114 L and  114 R by a bonding bead  118 . Further, as best seen in  FIG. 1D , left and right sidewall heat shrink film portions  116 L and  116 R respectively, overlie left and right sidewall flexible portions  114 L and  114 R to form a double film layer at those overlain parts of compaction package  100 . 
     Returning attention to compaction package  100 ,  FIG. 1B  is a perspective view of compaction package  100  of  FIG. 1A  after compaction by application of heat.  FIG. 1E  is a top sectional view of compaction package  100  of  FIG. 1B  taken along line  1 E′- 1 E′ of  FIG. 1B . Referring to  FIGS. 1A ,  1 B and  1 E together, in using compaction package  100  to secure and compact granular material, compaction package  100  is fabricated as described and filled with granular material  112  through opening  109  ( FIG. 1A ) to fill interior space  110  of compaction package  100  prior to application of heat. Next, filled compaction package  100  is heated to raise the temperature of left and right sidewall heat shrink film portions  116 L and  116 R above their critical heat shrink temperature. As noted, when heated above a certain critical temperature, PETG and other shrink films exhibit shrinkage biased in at least one direction, typically longitudinally along a length or transversely across a width of a shrink film. A heat tunnel (not shown) may provide sufficient heat to raise the temperature of left and right sidewall heat shrink film portions  116 L and  116 R above the critical heat shrink temperature. Other means of supplying at least localized heat sufficient to cause shrinkage of left and right sidewall heat shrink film portions  116 L and  116 R are possible. After application of heat and as shown in the  FIGS. 1B and 1E , left and right sidewall heat shrink film portions  116 L and  116 R have shrunk transversely across their respective widths, as indicated by heat shrink arrows  120 , thereby pulling front  105  and back  108  closer together and reducing the volume of interior space  110  of compaction package  100 . Left sidewall flexible portion  114 L and right sidewall flexible portion  114 R form pleats or folds  122  as shown to accommodate the shrinkage of left and right sidewall heat shrink film portions  116 L and  116 R to which they are respectively coupled. 
     When heat is first applied to compaction package  100 , left and right sidewall heat shrink film portions  116 L and  116 R are initially unconstrained and thus shrink to reduce the volume of interior space  110 . As the volume of interior space  110  decreases, compaction package  100  may be constrained from further shrinkage by contact with and compression of granular material  112  around which compaction package  100  shrinks. Said another way, the interstial spacing between individual granules of granular material  112  decreases. Upon further application of heat, tension in the films comprising compaction package  100  increases in response to compression of granular material  112 . Relative movement between individual granules of granular material  112  is constrained thereby reducing attrition of granular material  112  during handling, shipping, and storage. 
       FIG. 2A  is a top sectional view similar to the view of  FIG. 1C  showing another embodiment of a compaction package  200  in accordance with the principles of the present invention.  FIG. 2B  is a close up view of the area encircled by dotted line in  FIG. 2A  showing a bonding bead  218  coupling a right sidewall heat shrink film portion  216 R with a right sidewall flexible portion  214 R of compaction package  200 . Referring to  FIGS. 2A and 2B  together, in this embodiment, left and right sidewall heat shrink film portions  216 L and  216 R are coupled respectively to left and right sidewall flexible portions  214 L and  214 R but do not completely overlie left and right sidewall flexible portions  214 L and  214 R. In this embodiment, sidewall flexible portions are discontinuous, having a respective sidewall heat shrink film portion interposed between and coupled to edges of the discontinuous parts of the sidewall flexible portions. Left and right sidewall flexible portions  214 L and  214 R define gaps  215 L and  215 R, respectively, and do not completely underlie respectively left and right sidewall heat shrink film portions  216 L and  216 R to form a double film layer of the compaction package  100  of  FIG. 1C . Since the left and right sidewall flexible portions are discontinuous at the sidewall heat shrink film portions, less sidewall flexible material is used thereby reducing the material cost for compaction package  200  of  FIG. 2A  when compared to the material cost for compaction package  100  of  FIG. 1C . 
     In compaction package  200 , upon application of heat sufficient to shrink interposed left and right sidewall heat shrink film portions  216 L and  216 R, the edges of discontinuous left sidewall flexible portion  214 L and right sidewall flexible portion  214 R coupled respectively to left and right sidewall heat shrink film portions  216 L and  216 R are drawn closer together. Since, left sidewall flexible portion  214 L and right sidewall flexible portion  214 R are coupled to edges of the discontinuous parts of their respective sidewall flexible portions, little or no folding or pleating of left and right sidewall flexible portions  214 L and  214 R occurs as in compaction package  20  of  FIG. 2A . This feature of compaction package  200  provides a package with a smoother appearance without the pleats or folds of compaction package  100  of  FIG. 1B . Other embodiments of a compaction package in accordance with the principles of the present invention described below may utilized the discontinuous flexible portion techniques of compaction package  200  as well as the continuous flexible portion techniques of compaction package  100 . 
       FIG. 3  is a perspective view of another embodiment of a filled compaction package  300  in accordance with the principles of the present invention, prior to compaction and having an open top  302  and rectangular bottom  303 . Compaction package  300  is generally configured as a rectangular polyhedron surface defining an open-ended hollow container made from sheet material, having bottom  303  and rectangular sidewalls coupled to the peripheral side edges of bottom  303 . Compaction package  300  includes a front  305  coupled to both a left sidewall  306 L and a right sidewall  306 R (not seen in  FIG. 3 ), and a back  308  (not seen in  FIG. 3 ) opposite front  305  also coupled to both left and right sidewalls  306 L and  306 R to define an opening  309  and an interior space  310  adapted to contain a material. A shown in  FIG. 3 , a granular material  312  has been placed in interior space  310  through opening  309 . 
     In one embodiment of the compaction package  300  of  FIG. 3 , left sidewall  306 L includes a left sidewall flexible portion  314 L formed of, for example, conventional flexible polymer sheet material such as polyethylene film commonly used in flexible packaging. Coupled to left sidewall flexible portion  314 L of left sidewall  306 L, is a left sidewall heat shrink film portion  316 L. Similarly, right sidewall  306 R (not seen in  FIG. 3 ) includes a right sidewall flexible portion  314 R (not seen in  FIG. 3 ) of polyethylene film. Coupled to right sidewall flexible portion  314 R of right sidewall  306 R, is a right sidewall heat shrink film portion  316 R (not seen in  FIG. 3 ). Sidewall heat shrink film portions of compaction package  300  may be coupled to sidewall heat shrink film portions by various means. 
     As seen in  FIG. 3 , left and right sidewall heat shrink film portion  316 L is configured as isosceles trapezoids having a wide parallel end  320 W and a narrow parallel end  320 N. (In  FIG. 3  only right sidewall  306 R is shown; left sidewall  306 L is similarly configured). Each of the left and right sidewall heat shrink film portions  316 L and  316 R is coupled to its respective left and right sidewall flexible portion  314 L and  314 R such that wide parallel side  320 W of the isosceles trapezoid-shaped sidewall heat shrink film portion is nearest opening  309  at top  302  of compaction package  300 . 
     For transversely biased heat shrink film portion, upon application of heat sufficient to cause shrinkage of left and right sidewall heat shrink film portions  316 L and  316 R, the top  302  of the sidewalls  306 L and  306 R of compaction package  300  shrink a greater amount at opening  309  than at bottom  303  of compaction package  300  owing to the trapezoidal bottom to top expanding taper of left and right sidewall heat shrink film portions  316 L and  316 R. Since the width of the wide parallel end  320 W of the sidewall heat portions shrinks a greater distance across its width than the does the narrow parallel end  320 N bottom of the heat shrink film portions, the sidewall shrinkage of compaction package  300  is greatest at the top of compaction package  300  nearest opening  309 . 
       FIG. 4  is a perspective view of another embodiment of a filled compaction package  400  in accordance with the principles of the present invention, prior to compaction and having a rectangularly shaped bottom  403 . As shown in  FIG. 4 , a left and right sidewall heat shrink film portion  416 L and  416 R (not seen in  FIG. 4 ) are configured as “T” shaped film structures having a vertical part  420 V and a horizontal part  420 H. (In  FIG. 4  only right sidewall  406 R is shown; left sidewall  406 L is similarly configured). As in other embodiments described above, each of the left and right sidewall heat shrink film portions  416 L and  416 R is coupled to its respective left and right sidewall flexible portion  414 L and  414 R. In this embodiment, respective horizontal parts  420 H of sidewall heat shrink film portions  416 L and  416 R are nearest an opening  409  at the top of compaction package  400 . 
     In compaction package  400 , the “T” shaped left and right sidewall heat shrink film portions  416 L and  416 R are integrally formed from a sheet of heat shrink material prior to coupling respective sidewall heat shrink film portions. The heat shrink film portion forming sidewall heat shrink film portions  416 L and  416 R is biased to shrink only horizontally in a transverse direction across the film when exposed to a heat source of sufficient intensity. The heat shrink film portion is position and coupled to the flexible film portion of the compaction package such that the shrinkage bias of the shrink film is in the transverse, side-to-side direction of the compaction package. When so configured and formed, compaction package  400  will perform similarly to compaction package  300  of  FIG. 3 . The compaction package  400  shrinks a greater amount at top  402  than at bottom  403 . 
       FIG. 5A  is a perspective view of another embodiment of a filled compaction package in accordance with the principles of the present invention, prior to compaction and having an open top and a rectangular bottom.  FIG. 5B  is a perspective view of the compaction package of  FIG. 5A  after sealing of the open top and compaction by application of heat. Referring to  FIGS. 5A and 5B  together, in this embodiment, compaction package  500  is again generally configured as a rectangular polyhedron surface defining an open-ended hollow container made from sheet material, having a rectangular bottom  503  and rectangular upright walls coupled to the peripheral side edges of bottom  503 . Compaction package  500  includes a front  505  coupled to both a left sidewall  506 L and a right sidewall  506 R (not seen in  FIG. 5A  or  5 B), and a back  508  (not shown) opposite front  505  also coupled to both left and right sidewalls  506 L and  506 R to define an opening  509  and an interior space  510  adapted to contain a material  512 . 
     In this embodiment, strips of transversely biased heat shrink film portion  524  are coupled to and overlie part of a flexible film portion  514  of compaction package  500  at each of the side corner edges of compaction package  500  where its peripheral upright walls intersect. In this embodiment all four upright walls, i.e. the two sidewalls, the front and the back of compaction package will shrink transversely upon application of sufficient heat. As shown in  FIG. 5B , pleats  522  form in each of the four upright peripheral walls of compaction package  500  to accommodate the shrinkage of all of the upright walls. 
     It would be apparent to one of ordinary skill in the art that many variations in accordance with the principles of the present invention on the specific configurations and locations of the flexible and heat shrink film portions described herein are possible. Illustratively, front  105  and back  108  of compaction package  100  of FIGS  1 A- 1 C may also include heat shrink film portions similar to the sidewall heat shrink film portions shown. Accordingly, shrinkage of a compaction package having both lateral sidewall and front/back sidewall heat shrink film portions occurs in both the front-to-back direction and in the side-to-side direction upon application of heat sufficient to cause shrinkage of the heat shrink film portions of the compaction package. 
     Further, by way of illustration, in another embodiment, the bias of the heat shrink film portions may be longitudinal instead of transverse as described, thus causing shrinkage of the compaction package in a top-to-bottom direction upon application of heat sufficient to cause shrinkage of the heat shrink film portions. Alternatively, the heat shrink material making up the various heat shrink film portions described may shrink in both the transverse and longitudinal direction, thus causing shrinkage of the compaction package of the present invention to occur in any or all of the front-to-back, side-to-side, and top-to-bottom directions upon application of sufficient heat to the package. In yet another embodiment, and as described below with reference to  FIG. 6 , a compaction package in accordance with the principles of the present invention may be generally configured as a cylindrical surface having a circular bottom. 
       FIG. 6  is a perspective view of another embodiment of a filled compaction package  600  in accordance with the principles of the present invention having a circular bottom  603  and after compaction by application of heat. In compaction package  600 , a continuous upright wall  630  is coupled to the perimeter of circular bottom  603  forming a cylindrical shaped container defining an interior space  610  adapted to contain a granular material  612 . Compaction package  600  further includes one or more perforation lines  628  that circumscribe compaction package  600 . Perforation lines  628  form weakened portions of compaction package  600  and are designed to yield upon application of force on compaction package  600 . By this means, a portion of the granular material  612  may be separated from the remainder of compaction package  600  without disrupting the compaction of the remaining granular material in the remainder of compaction package  600 . 
     While the invention is described herein in connection with certain exemplar embodiments, there is no intent to limit the present invention to those embodiments. On the contrary, it is recognized that various changes and modifications to the described embodiments will be apparent to those skilled in the art upon reading the foregoing description, and that such changes and modifications may be made without departing from the spirit and scope of the present invention. Skilled artisans may employ such variations as appropriate, and the invention may be practiced otherwise than as specifically described herein. Accordingly, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the invention.