Abstract:
An improved insulated shipping container including an external or outer corrugated cardboard box, receiving an inner product box centrally disposed therein. Between the inner and outer cardboard boxes are plural strata or layers of insulating pellets compressed or compacted to a selected degree. Compression of the insulating pellets both interlocks these insulating pellets so as to prevent their migration during transit of the shipping container, and substantially reduces the interstitial space or volume that would otherwise exist among the pellets. The bulk insulating value of the pellets is significantly improved. The entire container is biodegradable, and may be composted.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The present invention relates to an improved insulated shipping container; with all or substantially all of the component parts of this container suitable for recycling (i.e., which are biodegradable, or can be composted). Thus, a shipping container according to this invention may be considered environmentally friendly, or “green.” More particularly, this invention relates to an insulated shipping container made essentially from selected biodegradable and compostable vegetable (i.e., plant based) materials. The most preferred insulating material being pelletized or granulated insulating material (i.e., vegetable starches); and which are also prevented from migration of the insulating material and shipped item during shipping. 
         [0003]    In order to better protect item(s) being shipped, the present container is especially configured and constructed to provide both shock absorption; and to provide temperature regulation through the use of a combination of particulate insulation (i.e., insulation pellets or granules). In order to provide temperature regulation within the container, a cooling material, such as refrigerated gel packs or dry ice, for example, may also be employed. 
         [0004]    Related Technology 
         [0005]    Traditionally, containers for shipping temperature sensitive products have generally included conventional cardboard shipping containers (i.e., cardboard boxes, for example) having an insulating material therein. The insulating material may be simple loose-fill Styrofoam “peanuts,” for example, in which a chunk of dry ice is placed along with the material to be shipped. Another variety of conventional insulated shipping container utilized panels or containers made of an insulating material, such as expanded polystyrene (EPS). EPS is a relatively inexpensive insulating material, and it may be easily formed into a desired shape, has acceptable thermal insulating properties for many shipping needs (i.e., typical R value of about 3.6 to about 4.0 per inch), and may be encapsulated or faced with protective materials, such as plastic film or metal foil, or plastic film/metal foil laminates. 
         [0006]    Containers including EPS are often provided in a multi-piece (i.e., usually six pieces) modular form. Individual panels of EPS insulation, possibly wrapped in foil or the like, are preformed using conventional methods, typically with beveled, mitered, or square (i.e., 90°) edges. The panels are then inserted into a conventional cardboard box type of shipping container, one panel against the floor wall, and against each side wall, to create an insulated cavity within the container. In this arrangement, the beveled edges of adjacent panels form seams at the corners of the container. This configuration compromises insulation value by losses through the seams, called edge losses. A product is placed in the cavity and either a plug (such as a thick polyether or polyester foam pad), or an EPS lid is utilized, and is placed over the top of the product before the container is closed and prepared for shipping. In many cases, a coolant, such as packaged ice, gel packs, or loose dry ice, is placed around the product in the cavity to refrigerate the product during shipping. 
         [0007]    Alternatively, an insulated body may be injection molded from expanded polystyrene (EPS), forming a cavity therein and having an open top to access the cavity. A product is placed in the cavity, typically along with coolant, and a cover is placed over the open end, such as the foam plug described above or a cover is also formed from EPS. In some uses, the brittle and breakable nature of EPS makes is less than satisfactory because of the possibility of damage to the container during transport. 
         [0008]    For shipping particularly sensitive products, such as certain medical or pharmaceutical products, expanded rigid polyurethane containers are often used, as expanded polyurethane has thermal properties generally superior to EPS. Typically, a cardboard container is provided having a box liner therein, defining a desired insulation space between the liner and the container. Polyurethane foam is injected into the insulation space, substantially filling the space and generally adhering to the container and the liner. The interior of the box liner provides a cavity into which a product and coolant may be placed. A foam plug may be placed over the product, or a lid may be formed from expanded polyurethane, typically having a flat or possibly an inverted top-hat shape. 
         [0009]    With all of the conventional shipping containers outlined above, many of the component parts of the container are not biodegradable, and recycling of the materials of the container is also problematic. Some countries, particularly the European countries, presently impose a tariff or tax on products that do not meet recycling guidelines. Many conventional insulated shipping containers do not meet these recycling guidelines, so that the costs of using such non-compliant containers is increased by the applied additional taxes. Particularly, insulated shipping containers of the type utilizing polyurethane foam injected into a space between an inner and an outer nested cardboard boxes create a particularly difficult disposal problem. When polyurethane is injected into such a container, it generally adheres substantially to the walls of both the inner and the outer cardboard box. Thus, the cardboard and insulation components may have to be disposed of together, entirely preventing recycling of the container. 
         [0010]    Accordingly, there is a need for an improved insulated shipping container which is “green” with substantially all of the components of the container being either biodegradable, or recyclable, or both. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is directed generally to an improved insulated shipping container for shipping a temperature sensitive product in a temperature regulated condition, which container is entirely recyclable or biodegradable. Further, the container is to provide physical protection from shocks and bumps as commonly occur during transport on common carriers, such as truck freight and air freight carriers. Further, the present invention is directed to such an insulated container that has insulating properties (i.e., R value) favorably comparable to EPS containers. 
         [0012]    One aspect of the present invention provides an improved insulating and cushioning shipping container, the shipping container comprising an exterior cardboard box defining a cavity, an inner cardboard box within the cavity, the inner cardboard box defining a product cavity, a compressed mass of insulating material of pellet/granular form received in the cavity and around the inner cardboard box; and the compressed mass of insulating material having a compression ratio of at least 1.125:1 in comparison to a free-flowing loose-filled condition of the pellet/granular insulating material, whereby pellets/granules of the insulating material mutually engage and, interlock with one another, and the compressed insulating material provides a thermal insulating value (R value) substantially equal to EPS. 
         [0013]    According to another aspect, the present invention provides a method of providing an improved insulating and cushioning shipping container, the method comprising steps of: providing an exterior cardboard box defining a cavity; disposing an inner cardboard box within the cavity, utilizing the inner cardboard box to define a product cavity; disposing a compressed mass of insulating material of pellet/granular form received in the cavity around the inner cardboard box; and arranging the compressed mass of insulating material to have a compression ratio of at least 1.125:1 in comparison to a free-flowing loose-filled condition of the pellet/granular insulating material, and utilizing compression of the mass of insulating material to mutually engage and interlock pellets/granules of the insulating material with one another, and further utilizing the compressed insulating material to provide a thermal insulating value (R value) substantially equal to EPS. 
         [0014]    Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0015]      FIG. 1  presents a perspective view of an insulated shipping container according to the invention, having a portion of the container sectioned or broken away for clarity of illustration; 
           [0016]      FIG. 2  is a cross sectional view of the container seen in  FIG. 1 , with the cross section taken along a vertical plane  2 - 2  of  FIG. 1 , extending transversely through the container; 
           [0017]      FIGS. 3-14  are diagrammatic cross sectional views somewhat similar to  FIG. 2 , and illustrating steps in the process of manufacturing an insulated shipping container embodying the present invention; 
           [0018]      FIGS. 15, and 16  provide respective diagrammatic views of a conventional cushioning (i.e., packaging) or insulating “peanut” and of a pelletized or granular insulating element according to this present invention; 
           [0019]      FIG. 17  is a graphical representation of the insulating performance of an insulated container embodying this invention in comparison to the performance of a conventional EPS container in an ISTA “summer” test cycle; 
           [0020]      FIGS. 18 and 20 , respectively, provide a sectioned perspective view, and a cross sectional view, each being similar to  FIGS. 1 and 2 , but showing an alternative embodiment of inventive shipping container; and 
           [0021]      FIG. 19  is a perspective view of a component part of the shipping container shown in  FIGS. 18 and 20 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Turning now to the drawings, and considering  FIGS. 1 and 2  in conjunction, these Figures show a perspective view of an insulated shipping container  10  according to the invention, with  FIG. 1  having a portion of the container sectioned or broken away in the corner nearest the viewer for clarity of illustration. In  FIG. 2 , a cross sectional view of the insulated container  10  is presented, with the plane of the cross section indicated generally at the dashed line  2 - 2  of  FIG. 1 —extending transversely across the container—and looking in the direction of the arrows. In  FIG. 2 , an article  12  to be shipped is shown within an internal cavity  14  of the container (to be further described below), sandwiched between a pair of refrigerated gel packs  16 . The gel packs  16  are provided to control the temperature of the item  12  to an acceptably low level during transport. 
         [0023]    Still considering  FIGS. 1 and 2 , an insulated shipping container  10  in accordance with the present invention generally includes an exterior cardboard (i.e., corrugated cardboard or paper board) shipping container or box  18 , including plural (in this case, four) side walls each indicated with the numeral  18   a.  A bottom wall  18   b  is cooperatively formed by plural lower flaps  18   c  each hingeably attaching at a lower marginal extent of the side walls  18   a.  A top wall  18   t  (best seen in  FIG. 2 ) is similarly formed cooperatively by plural flaps  18   u  hingeably attaching at an upper marginal extent of the side walls  18   a.  It will be noted that in this instance, the upper flaps  18   u  are alike to the lower flaps  18   c,  although the invention is not so limited. In  FIG. 1 , the top wall of the box  18  is shown in its open configuration. The side wall  18   a  thus are seen to cooperatively define an upper opening  18   d,  leading to a rectangular prismatic cavity  17 . 
         [0024]    As is seen in both  FIGS. 1 and 2 , generally centrally received into the cavity  17  of container  10  (i.e., within outer box  18 ) is a dimensionally smaller inner box  20 , preferably also formed of cardboard or paper board. The construction of the inner box  20  is substantially like that of the outer box  18 . In both  FIGS. 1 and 2 , the upper flaps  20   u  of the inner box  20  are illustrated to be closed, although those ordinarily skilled in the pertinent arts will understand that they can be opened as is shown for the outer box  18  in  FIG. 1 . 
         [0025]    Closely considering now  FIGS. 1 and 2  together, it is seen that adjacent to both the bottom wall  18   b  and side walls  18   a  of the outer box  18  (and interposed between these walls of the outer box  18  and the walls of the inner box  20 ) is a layer of insulation material (generally indicated with the numeral  22 ). This insulating material is indicated on  FIGS. 1 and 2  to consist of several layers or “strata,” indicated respectively with the numerals  22   a,    22   b,    22   c,  and  22   d.  These strata  22   a - 22   d  of insulating material are each formed as will be explained further below. But, for the present, it is to be understood that each strata consists of granular or pelletized insulating material that has been compressed “in situ” by a determined degree or amount from an initial “loose fill” or free-flowing condition. 
         [0026]    As a predicate to the following description of a method of making the container  10 , and in order to better appreciate and understand the significance of the selected or determined degree of compression of the granular insulating material  22  in the respective strata, attention may now be turned briefly to  FIGS. 15 and 16 . Although not to scale or to be understood or taken as precise representations, the insulating pellets, granules, or “peanuts” shown in  FIGS. 15 and 16  are approximately full size. In  FIG. 15  is shown a conventional or prior-art foamed or “puffed” cylindrical plastic cushioning “peanut  24 ” of the type generally used to cushion (and sometimes to insulate) items to be shipped. As is seen in  FIG. 15 , this conventional foamed pellet is about one inch to about one and one-half inches in length and has a diameter about one-half its length (both indicated by respective arrows on  FIG. 15 —with the length indicated in the vertical direction and the width or diameter dimension indicated in the horizontal direction). These conventional cushioning pellets have a bulk density of about 265.5 grams per cubic foot. When such conventional pellets are used to cushion or insulate an item to be shipped within a box the pellets are generally introduced or poured (i.e., free flowing condition) into the box around the item to be shipped in a “loose fill” condition, perhaps with a small excess of pellets to be pushed into the box when the flaps of the box are closed. This slight over filling of the box simply has the effect of somewhat resisting migration of the pellets around the item being shipped during the vibration of jostling of carriage. Consequently, settling or raising of the item being shipped within the bulk of the cushioning pellets is somewhat resisted. The over filling of the box with conventional cushioning pellets does not accomplish a consistent or uniform compressing of the conventional pellets. Further, a difficulty arises when the conventional pellets are used for insulation, in that their relatively large size and inconsistent pushing into the box as the box is closed (due to slight over filling) leaves a large interstitial or ullage volume inside the box. This large interstitial volume allows for air circulation around and among the conventional cushioning pellets and a provides a very poor insulation value. 
         [0027]    On the other hand, consideration of  FIG. 16  shows a preferred size for a cylindrical insulating pellet  26  to be used in the practice of this invention. This preferred insulating pellet is also made of foamed Material (as is to be further explained), and has a length of about five-eight of an inch or less, and a diameter of about one-half of its length (both indicated by respective arrows on  FIG. 16 ). Significantly, this preferred insulating pellets have a bulk density in their “loose fill” free flowing condition from about 287.5 grams per cubic foot to over 400 grams per cubic foot. Accordingly, because the foam from which the pellets of  FIGS. 15 and 16  are made is substantially the same, it is to be appreciated that the pellets of  FIG. 16  appear to have a substantially smaller or decreased ullage volume (or interstitial volume) compared to the pellets of  FIG. 15 . The bulk density, or weight per cubic foot, of the insulating pellets of  FIG. 16  is from about 10% higher to about 150% higher than the cushioning pellets of  FIG. 15 . 
         [0028]    Even more significantly, a multitude of the preferred insulating pellets  26  as seen in  FIG. 16  are disposed in the container  10  in a compressed bulk form in order to cooperatively form the strata  22   a - 22   d.  These strata of compressed pellets each have a selected or desired degree of compressing (or compression) from the “loose fill” condition of pellets  26 , and the compression of pellets  26  in the strata  22   a - 22   d  is substantially uniform. As a result, the strata  22   a - 22   d  exhibit a much lower interstitial volume than can be accomplished with conventional pellets or peanuts as seen in  FIG. 15 . Further, because of the selected or desired degree of compression of the pellets  26  in the strata  22   a - 22   d,  the pellets are effectively “locked” into engagement with one another, and migration of the pellets  26  comprising strata  22   a - 22   d  is positively prevented. 
         [0029]    Turning now to  FIG. 3 , a tool  28  to be used in making the container  10  is diagrammatically illustrated. The tool  28  consists of a hollow base  30  carrying a plateau  32  penetrated by an array of vacuum holes  34 , circumscribing an upstanding mandrel  36 . Arrow  38  indicates communication of the hollow base  30  to a controllable vacuum source.  FIG. 4  shows that the mandrel is sized to slip closely in supporting relationship within the inner box  20 . That is, the inner box  20  in inverted orientation is slipped over the upstanding mandrel  36 , as is indicated by the movement arrow on  FIG. 4 .  FIG. 5  illustrates in cross section the inner box  20  in place on mandrel  36 , and upon plateau  32  on base  30 . It will be noted that the plurality of vacuum holes  34  also circumscribe the inner box  20 . 
         [0030]      FIG. 6  illustrates a subsequent step in the method of making container  10 , in which the outer box  18 , also in inverted orientation, is placed on the base  30 , with the plateau  32  fitting within the upper (now oriented downwardly) opening  18   d.  The vacuum holes  34  are thus disposed within the outer box  18  (i.e., between the inner box  20  and outer box  18 ). In this orientation of the outer box  18 , the bottom wall  18   b  (i.e., formed by bottom flaps  18   c ) is open upwardly, as is seen in  FIG. 6 . A pliable bag  40  of film material is introduced over the inner box, spanning across the plateau  32  and vacuum holes  34 , and extending upwardly on the open bottom flaps  18   c,  to embrace (i.e., be folded over) these bottom flaps  18   c.    
         [0031]    Subsequently, as is seen in  FIG. 7 , the bottom flaps  18   c  are forming the upwardly oriented opening of the bag  40  into an entrance to the upwardly disposed bag  40  and bottom of the box  18 , as is best seen in  FIG. 7 . At this time, structural support for the side walls  18   a  of box  18  is provided, as is indicated on  FIG. 7  by the plurality of arrows  42 . The arrows  42  do not indicate that inward force is applied to the side walls  18   a,  but simply that these side walls  18   a  are supported against outward movement or bulging. 
         [0032]      FIG. 8  diagrammatically illustrates that the vacuum source  38  has been turned on, at least momentarily, in order to pull the film bag  40  into embrace with the inner box  20 , the plateau  32 , and the outer box  18 . The timing of this application of vacuum is not critical, and can be performed as part of the steps illustrated in any one or all of  FIGS. 6 through 8 . As seen in  FIG. 8 , a first (i.e., upper) strata  44  of loose-filled granular or pelletized insulating material (i.e., plural pellets  26  as seen in  FIG. 16 ) are being filled into the space between the inner box  20  and outer box  18  within the film bag  40 . As is indicated by the depth of this strata  40  in comparison with the strata  22   d  seen best in  FIG. 2 , it is to be appreciated that in the loose-filled condition of the strata  44 , the depth is considerably greater than the depth of corresponding strata  22   d.  However, as  FIG. 9  illustrates, the strata  44  of loose-filled pellets  26  is compressed by substantially uniform application of downwardly directed force (indicated on  FIG. 8  with the arrows  46 ). It is to be noted that the compression force and movement indicated by arrows  46  is applied substantially uniformly across the upwardly exposed surface of the strata  44  and around the circumference of the strata  44  between the inner box  20  and outer box  18 . That is, the pellets  26  are substantially uniformly compressed in strata  44  from their loose-filled, free-flowing condition to a compressed or compacted condition, producing the strata  22   d.  As will be further explained, the strata  44  of loose-filled pellets or granules  26  is thus compressed to a sufficient degree (to be further explained below) that the upper strata  22   d  is produced. The strata  22   a - 22   d  of multiple pellets  26  thus compressed or compacted will be recognized as effective thermal insulation (i.e., inhibiting heat transfer) disposed between the inner box  20  and outer box  18 . 
         [0033]      FIG. 10  illustrates that by subsequent repeated application of the method steps indicated in  FIGS. 8 and 9 , the subsequent strata  22   c  and  22   b  are produced in the volume (i.e., in that circumferential space) surrounding inner box  20  and within outer box  18 . During the compression of these strata  22 , the support (arrows  42 ) prevent the compression force (arrows  46 ) from resulting in the side walls  18   a  of box  18  being pushed or bulged outwardly by transferred compression force. 
         [0034]    Turning to  FIG. 11 , the provision of the strata  22   a  within box  18  is illustrated. Again, loose-filled pellets  26  are provided to a depth greater than the desired thickness of strata  22   a,  in order to accomplish substantially the same compression of the pellets  26  as has been done for strata  22   d,    22   c,  and  22   b  (in the order of the creation of these strata). However, as  FIG. 11  illustrates, in order to create the strata  22   a,  the loose filled pellets  26  are captured inside of the material of the film bag  40 , which is gathered and folded over these loose-filled pellets  26  of strata  22   a.  The bottom flaps  18   b  of box  18  are then forcefully closed (refer to  FIG. 12 ) on the loose-filled pellets  26  of the strata  22   a,  and force is applied (indicated by arrows  48 ) in order to bring the bottom flaps  18   b  of box  18  into position as seen in  FIG. 12 . In this way, the strata  22  is subjected to substantially the same degree or amount of compression of the pellets  26  as are the other strata  22   d,    22   c,  and  22   b.    
         [0035]    Finally (as is indicated by the action arrows  50  on  FIG. 13 ), a plurality of conventional plastic filament securing devices (or staples)  52  is inserted downwardly from the outside of box  18 . These staples are inserted through the folded-closed bottom flaps  18   a  of box  20 , through the strata  22   a  of compressed pellets  26 , and through the bottom of box  20 . Each of the plastic filament devices  52  have a spaced apart end pair of integral cross bars or tie bar portions, which respectively engage the bottom flaps of outer box  18  and the bottom of inner box  20 . Thus, maintaining the position of inner box  20  within the outer box  18 , and within the plural strata  22   a - 22   d  of compressed pellets  26  is assured. An advantage of this “stapling” of the inner box  20  into position within outer box  20  is that in the event that the shipping container is jostled during handling, or a worker were to tug on the flaps of inner box  20  during filling of this box, for example, the inner box  20  is not easily dislodged from its proper position within the strata of pellets  22   a - 22   d.    
         [0036]    Turning now to  FIG. 14 , it is seen that the container  10  has been removed from the tool  8 , and has been turned over to its normal or upright orientation. In this orientation, the item  12  to be shipped, as well as any temperature control packs  16  to be utilized can be placed into the inner box  20  (recalling  FIG. 2 ). The upper flaps of the inner box  20  are then closed (or alternatively, in the event an inner box  20  without top flaps has been used, a closure piece of flat cardboard (not seen in the drawing Figures) is employed to span and close the opening of inner box  20 ). Subsequently, a generally flat and correspondingly sized film bag  54  having an outer film layer  56  (i.e., like the film of bag  40 ) and an inner filling (not visible in the drawing Figures) of loose-filled insulating pellets  26  is provided. This generally flat bag  54  is placed in the top of box  18  atop of the upper strata  22   d  of compressed pellets, and atop of the closed inner box  20 . Desirably, this bag  54  has a volume greater than the remaining space within outer box  18 , generally according to the desired compression to be accomplished for the insulating pellets  26 —recalling the description of compressed strata  22   a - 22   d  provided above. Once the bag  54  is placed into the opening of box  18 , the upper flaps  18   u  are folded over the bag  54 , and vertically downwardly directed force (arrows  58  of  FIG. 2 ) is applied both to compress the pellets  26  of insulating material within bag  54 , and to conform the shape of bag  54  to the shape of the remaining space within box  18  (i.e., atop of strata  22   d  and atop of the closed inner box  20 ), viewing  FIG. 2 ). Further, it is to be noted that the bag  54  has provisions for allowing air trapped therein to escape during the compression of this bag and the pellets therein to the desired shape. Expedients that have been used are to have a few needle punches or slits formed in the film  56  from which the bag  54  is made. 
         [0037]    It will be noted in  FIG. 2 , that as compressed into place, the bag  54  takes on a stepped or rabbeted shape, with an upper peripheral portion  54   a  which is highly compressed atop of strata  22   d,  and an inner portion  54   b  which is not so highly compressed atop of the closed inner box  20 . Thus, a desirable air or respiration sealing engagement of bag  54  is accomplished with the strata  22   d  of compressed pellet insulation within the box  18 . Once the flaps  18   u  have been closed, adhesive tape may be employed to retain these flaps in their closed positions. It is to be noted that although the film bags  40  and  54  are not impermeable, they do provide a barrier against moisture migration into the container  10 , thus minimizing condensation of liquid water within the cavity  14 . The bags  40  and  54  also are believed to contribute to retention of sublimation gas within the container  10  when dry ice is utilized as a cooling agent, further contributing to a desirable increase in the R value of the container  10 . Also, it is to be noted that a variety of bags  40 ,  54 , made of a variety of film materials, may be utilized in making the insulated container  10  according to this invention, and indeed, a container according to this invention may be made without using a bag  40  at all, as will be further explained. 
         [0038]    Recalling the disclosure above of the foamed nature of the pellets  26 , it is to be noted that most preferably, the insulating pellets  26  are formed of foamed or “puffed” vegetable starch. A most preferred material for making the insulating pellets  22  is corn starch. In the event the pellets  26  are made of corn starch, then a desired compression for these pellets is at least 1.125:1. A higher compression ratio may be employed as is explained below. On the other hand, alternative vegetable and natural materials may be employed to make the pellets  26 , or to make a granular or pellet form of insulating material for us in container  10 . One material that has been employed successfully to make pellets  26  is sorghum starch. In the event that sorghum is utilized to make the pellets  26 , then a desired compression for these pellets is substantially at least 1.125:1. Experimentation has shown that for relatively small containers  10 , a compression ratio for sorghum based pellets is 1.25:1 is particularly satisfactory in providing an insulation value as good as or better than EPS. For larger containers  10  (i.e., larger than about 10 inches in any direction), a compression ratio or 1.35:1 provides the desired insulation value (i.e., equal to or better then EPS). Similarly, while the film for bags  40  and  54  (i.e., film  56 ) may be made of a variety of materials, the most preferred material for making this casing is also a flexible corn starch film, which is biodegradable. Alternatively, the film for bags  40  and  54  may be made of a commercially available polyethylene sheeting having an ingredient added so that it biodegrades quickly. 
         [0039]    Further considering the compression of pellets  26 , and the substantial reduction in interstitial volume or space achieved, it will be understood that when such insulating pellets are loose-filled together into a space or volume, they define considerable interstitial spaces, and these interstitial spaces communicate with one another. Moreover, although the communicating interstitial spaces define tortuous communication pathways through a layer of such pellets, a considerable air circulation can take place, and the insulating value of loose-filled pellets is not satisfactory. Testing has confirmed this assertion. On the other hand,  FIG. 17  graphically illustrates a performance comparison for a container made according to this present invention versus a conventional EPS container. Both containers were cooled by a matching quantity of dry ice. The test protocol, generally, is the 24 hour ISTA Summer test, which has been made more severe for test purposes by extending the test beyond 24 hours (i.e., by more than an additional 6 hours), and by keeping the temperature of the test chamber at its highest level in the interval beyond 24 hours. Considering  FIG. 15 , it is seen that throughout the entire 24 hour ISTA Summer test, the temperature within a container  10  according to this invention remains desirably lower than the temperature within a comparable insulated container made of EPS. As the ISTA Summer test is drawing to a close, near the last 5 hours of this standard test cycle, the container embodying this invention maintains a considerably lower internal temperature. In fact, at least for an additional 6 hours (until the test was terminated), the insulated container according to this present invention maintained a significant advantage over the conventional EPS container. 
         [0040]    Further to the above, it has been discovered in the course of making and testing containers according to this invention that the compressed or compacted nature of the natural vegetable insulating materials utilized appears to result in a favorable retention of the sublimation gas (i.e., carbon dioxide) released when dry ice is utilized in the container for cooling purposes. That is, the cool carbon dioxide resulting from sublimation of the dry ice is not allowed to easily escape from the container because of respiration or free-flowing circulation or permeation of the container is inhibited. Thus, the cool carbon dioxide is retained more effectively in the container  10  (i.e., in the insulation of the container as well), and warm outside air is apparently inhibited from respiration into the container  10 . The result is an increase or improvement in the insulating value (i.e., “R” value) of the container. Still further, it has been determined that materials other than the mentioned corn or sorghum materials may be utilized to form a granular or pellet form of insulating material for this present invention. That is, materials such as corn husks, corn stalks, coffee husks, coconut husks, cotton fibers (waste or recycled), and mushrooms could be used to make insulation material according to this invention. All of these alternative insulating materials are also biodegradable/compostable. 
         [0041]    Turning now to  FIGS. 18, 19, and 20  in conjunction, these Figures show a sectioned perspective view, and a cross sectional view of an alternative embodiment of insulated shipping container  10 ′ according to the invention.  FIG. 19  illustrates a component part of the insulated container  10 ′. Viewing  FIGS. 18 and 20  in comparison with  FIGS. 1 and 2 , it is immediately seen that the two embodiments of the invention thus illustrated are very similar. Because of the similarity of the two embodiments of inventive shipping container, the same reference numerals employed earlier to indicate features of the first embodiment are utilized for the embodiment of  FIGS. 18 and 20 , but with a prime (′) added. However, the embodiment of  FIGS. 18 and 20  does not employ a bag  40  to contain the pellets  26 . Instead, the embodiment of  FIGS. 18 and 20  does utilize a cardboard partition member  60 , as is best seen in  FIG. 19 . This cardboard partition member  60  is sized and shaped to span and substantially close the circumferential, peripheral space between inner box  20 ′ and outer box  18 ′ (viewing  FIG. 18 ). 
         [0042]    Turning to  FIG. 19 , it is seen that the partition member  60  includes a central opening  62  sized and shaped to receive the inner box  20 ′. As  FIG. 18  shows, the cardboard partition member  60  is disposed substantially co-extensively with or co-planar with the top of box  20 ′. Into this central opening  62  projects a plurality of integral tabs  64 , which can be seen in  FIG. 18  (i.e., in dashed lines) folded downwardly so that they, enter matchingly positioned slots formed in the top of inner box  20 ′. These tabs  64  may alternatively or additionally be glued to the box  20 ′. Also viewing  FIG. 19 , it is seen that the partition member includes outwardly projecting integral tab portions  66 , which in  FIGS. 18 and 20  can be seen to engage into matchingly positioned slots defined by the outer box  18 ′. Again, the partition member  60  may alternatively or additionally be glued to the inside of outer box  18 ′. Thus, the upper extent of the compressed or compacted strata  22   b ′ of pellets  26  is protected by the cardboard partition member  60 . The partition member  60  assists in retaining the inner box  20 ′ with in the outer box  18 ′. So, the box  10 ′ may or may not utilize staples  52 , like were utilized by the first embodiment. Experience has shown that the cardboard partition member  60  by itself is sufficient in many uses of the container  10 ′ to secure the inner box  20 ′ during handling and preparations of the container  10 ′ for use and during shipping. 
         [0043]    While the invention is susceptible to various modifications, and alternative forms, a specific example thereof has been shown in the drawings and is herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the appended claims.