as shown in fig1 a shipping container 10 is comprised of three basic elements which are assembled to form the improved insulative container of this invention . the outermost component of the insulated container is the paperboard box 11 which is conventional in form and well known in terms of construction to those skilled in the art . located interiorly to and within the box is a plastic bag 12 which forms the vapor barrier of the invention . the plastic bag is also of conventional fabrication , preferably consisting of polyethylene film having thickness of approximately 2 mills . emplaced within the plastic bag 12 and within the cardboard box 11 is an insulative layer formed of six foam slabs or panels , which are non - integral with each other and which are placed separately within the bag 12 and box 11 upon assembly of the container . the panels are composed of an open - celled flexible , compressible and resilient foam , such as urethane foam , and include four side panels 13 , a bottom panel 14 and a top panel 15 . the panels are all sized to fit within the bag and box so as to meet along adjacent edges in abutting relationship . in such a configuration , the panels compressible contact each other along the side edges , thereby providing support , one against the other , thus maintaining the panels in a relatively fixed position within the bag and box . this facilitates both the assembly of the insulative shipping container and the loading of the same . a rigid load support 16 is provided for the bottom of the container to receive the product or products which are to be shipped as well as any refrigerant or heat source which is to be carried by the container . as fig2 shows , the introduction of a vapor barrier located exterior to the open - celled foam significantly increases the ability of the storage compartment to maintain a desired temperature environment . flexible , open - celled urethane foam ( line a ) provided with such an exterior vapor barrier formed from a 2 mill polyethylene film effectively matches the holding characteristics of the rigid closed - celled polystyrene foam ( line b ). open - celled urethane foam without an associated vapor barrier is significantly less able to hold or maintain a limited temperature range ( line c ). thus , the use of the vapor barrier in conjunction with the flexible , compressible open - celled foam yields a storage compartment which effectively combines the thermal insulative abilities of the closed - celled polystyrene with the damage resistant , product - protective features of the flexible foam . the assembly of the insulated shipping container is quickly and easily accomplished . first , an appropriate paperboard box - blank is erected to form the box 11 . the plastic bag 12 is next inserted through the open top of the box 11 , and opened and spread out to roughly follow the interior contour of the box . the side panels of insulation 13 are next inserted and arranged in the previously described edge - abutting fashion along the interior of the bag and box . the bottom panel of insulation 14 is then set between the four side panels 13 and pressed to the bottom of the box 11 , its edges in abutting contact with the adjacent side panels 13 . next , the rigid load support 16 is positioned on top of the bottom panel 14 . the product and refrigerant or heat source ( not shown ) are then placed within the storage compartment . the storage area thus formed is then closed by emplacement of the top panel 15 which is set upon the upwardly extending side edges 17 of the side panels 13 , such that the top panel 15 effectively encloses the storage compartment . the emplacement and positioning of the respective panels within the bag and box advantageously requires no fixation means , the panels maintained in place through compression forces exerted on the edges of the panels , one with another and against the bag and interior of the paperboard box . once the top panel 15 has been emplaced and the storage compartment closed , the plastic bag 12 is then folded over thereby creating a vapor barrier surrounding the entire cold storage compartment . the paperboard box 11 may be sealed by conventional means , such as by taping shut . as easily as the insulative container 10 of this invention is assembled , it is just as quickly disassembled for storage or compact re - shipment . all of the components of the container can be folded and stacked into a neat , lightweight planar package which is easily transportable for re - shipment or re - use , or easily stored for re - use in the future . it can thus be seen that this invention provides an insulated shipping container which can be manufactured at low cost from a minimum of elements and is easily assembled and disassembled by the user as needed , and which provides good thermal and protective qualities with an advantageous ability to hold a desired limited temperature range for an extended period of time . while the principles of the invention have now been made clear in an illustrative embodiment , there will be immediately obvious to those skilled in the art man modifications in the practice of the invention which can be accomplished without departing from those principles .