Patent Publication Number: US-7896182-B1

Title: Coated-poly containers

Description:
GOVERNMENT INTEREST 
     The invention described herein may be manufactured, used and licensed by or for the U.S. Government. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to containers, and more particularly to a container exhibiting high strength, lightweight, and insulating properties adapted for facilitating safe bulk storage and transport of goods and cargo. 
     BACKGROUND OF THE INVENTION 
     Since the beginning of the American Revolutionary War, the United States Army has depended on the use of wooden boxes and crates to support its shipping, storage and logistic needs. Now, more than 230 years later, the U.S. Department of Defense still relies on the use of millions of wooden boxes and crates for supporting the same needs. Although wooden boxes and crates have provided useful service, they are generally expensive, heavy for the carry volume, and not environmentally friendly. Wooden boxes and crates are time consuming and labor intensive to assemble. They also do not offer a high degree of protection against the elements for the goods and cargo being stored or transported particularly against water/moisture and fluctuating temperature changes. 
     Such wooden boxes and crates including cleated plywood boxes are typically assembled by fastening wooden panels and lumber with nails, screws, strapping (poly or steel), and the like. The assembling process thus requires the use of additional materials/tools for fastening. The wooden box or crate may require disassembly to minimize space for subsequent re-use. The disassembly process is also time-consuming and labor intensive. The high cost and the time consuming nature of a carpenter built wooden box or crate further diminishes their ease of use and accessibility. 
     Corrugated cardboard materials are also used to make shipping containers. Such containers are relatively inexpensive, but are very easily damaged and have limited reusable capabilities. With cardboard boxes, if one of the sides is damaged, the structural integrity of the package is compromised. When the items to be packaged are heavy in weight or have a high density, the container must have a high bursting factor to support the stress (pounds per square inch) generated by this heavy weight. To obtain the proper high bursting factor, the container is reinforced either by double boxing, or by using boxes of double or triple wall thickness. This greatly reduces the carrying volume and significantly increases the weight of the box. Furthermore, cardboard boxes provide little or slight protection against the elements and must be kept dry to prevent disintegration. 
     Accordingly, there is a need to develop a container exhibiting high strength, lightweight, and insulating properties for facilitating safe bulk storage and transport of goods and cargo. There is a further need for a container that is cost effective and simple to fabricate and implement. There is a need for a container designed with enhanced bursting strength, exceptional stacking strength, low thermal conductivity, pierce-resistance, wear/abrasion-resistance, acid/corrosion-resistance, and enhanced carrying volume to weight ratio, while remaining relatively compact and lightweight. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to a container exhibiting high strength, lightweight, and insulating properties, and adapted especially for facilitating safe bulk storage and transport of goods and cargo. The container of the present invention is designed with enhanced bursting strength, exceptional stacking strength, low thermal conductivity, pierce-resistance, wear/abrasion-resistance, acid/corrosion-resistance, and enhanced carrying volume to weight ratio, while remaining relatively compact and lightweight. The robust structure of the container of the present invention further provides enhanced shock absorbing performance. The container of the present invention is further designed to effectively protect the goods and cargo contained therein from the external effects of the environment including passage of water/moisture and extreme temperature changes. 
     The container of the present invention comprises interlocking panels, sections or portions providing ease of assembly without the need for tools or the efforts of skilled personnel. The panels of the container are adapted to form tight joints exhibiting high tensile strength. The container of the present invention further includes a coating of polyurea extending over at least the exterior portions of the panels, which provides high exterior strength and exceptional performance. In a preferred embodiment of the present invention, the polyurea coating is a unitary layer covering at least substantially the entire exterior surface of the container. The container of the present invention can be readily recycled or re-used, thus further being environmentally friendly. 
     The container of the present invention is simple and cost effective to fabricate and implement. The container of the present invention is compact, lightweight and rugged, and can easily accommodate any goods or cargo. The container of the present invention is suitable for shipping and storage use and is especially suitable for use in the military sector, where extreme environments including battlefield and urban warfare conditions are typically encountered. 
     In one aspect of the present invention, there is provided a container for facilitating storage and transport of goods and cargo, comprising: 
     a top portion; 
     a base portion; 
     a sidewall portion, whereby the top and base portions are adapted for positioning the sidewall portion there between; 
     the top, base and sidewall portions further defining an interior cavity; and 
     a polyurea layer of sufficient thickness adhering to and coating at least the exterior areas of the top, base and sidewall portions thereof. 
     In a further aspect of the present invention, there is provided a container for facilitating storage and transport of goods and cargo, comprising: 
     a top portion; 
     a base portion; 
     a sidewall portion, whereby the top and base portions are adapted for positioning the sidewall portion there between; 
     the top, base and sidewall portions further defining an interior cavity; 
     the sidewall portion comprises a plurality of panels, each of the plurality of panels includes end portions configured for interlocking engagement with one another to form a rigid joint exhibiting tensile strength there between; and 
     a polyurea layer of sufficient thickness adhering to and coating at least the exterior areas of the top, base and sidewall portions thereof. 
     In another aspect of the present invention, there is provided a container for facilitating storage and transport of goods, comprising: 
     a top panel; 
     a base panel; 
     an opposing pair of side panels; 
     an opposing pair of end panels; 
     the pair of side panels and the pair of end panels each including means for interlocking opposing end portions with one another, whereby in the interlocked state the side and end panels form a rigid structure surrounding an interior storage volume with open top and bottom portions; 
     the base panel being adapted for receiving and closing off the open bottom portion of the interlocked pairs of side and end panels; and 
     the top panel being adapted for receiving and closing off the open top portion of the interlocked pairs of side and end panels thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are illustrative of embodiments of the present invention and are not intended to limit the invention as encompassed by the claims forming part of the application, wherein like items are identified by the same reference designations: 
         FIG. 1  is a perspective view of a container for facilitating bulk storage and transport of goods and cargo for one embodiment of the present invention; 
         FIG. 2  is an exploded assembly view of the container in accordance with the present invention; 
         FIG. 3A  is a plan view of an exterior side of a panel or portion for forming top and base portions of the container in accordance with the present invention; 
         FIG. 3B  is a plan view of an interior side of the panel of  FIG. 3A  in accordance with the present invention; 
         FIG. 3C  is a side elevational view of the panel of  FIG. 3A  in accordance with the present invention; 
         FIG. 3D  is an elevational view looking from one end of the panel of  FIG. 3A  in accordance with the present invention; 
         FIG. 4A  is a side elevational view of a side panel or portion for forming side portions of the container in accordance with the present invention; 
         FIG. 4B  is a plan view of the side panel of  FIG. 4A  in accordance with the present invention; 
         FIG. 4C  is an elevational view looking from one end of the side panel of  FIG. 4A  in accordance with the present invention; 
         FIG. 5A  is an elevational view of an interior side of an end panel or portion for forming end portions of the container in accordance with the present invention; and 
         FIG. 5B  is a top plan view of the end panel of  FIG. 5A  in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates generally to a container exhibiting high strength, lightweight, and insulating properties, and adapted especially for facilitating safe bulk storage and transport of goods and cargo. The container of the present invention is designed with enhanced bursting strength, exceptional stacking strength, low thermal conductivity, pierce-resistance, wear/abrasion-resistance, acid/corrosion-resistance, and enhanced carrying volume to weight ratio, while remaining relatively compact and lightweight. The robust structure of the container of the present invention further provides enhanced shock absorbing performance. The container, of the present invention is further designed to effectively protect the goods and cargo contained therein from the external effects of the environment including passage of water/moisture and extreme temperature changes. 
     The container of the present invention comprises interlocking panels, sections or portions providing ease of assembly without the need for tools or the efforts of skilled personnel. The panels of the container are adapted to form tight joints exhibiting high tensile strength. The container of the present invention further includes a coating of polyurea extending over at least the exterior, portions of the panels, which provides high exterior strength and exceptional performance. In a preferred embodiment of the present invention, the polyurea coating is a unitary layer covering at least substantially the entire exterior surface of the container. The container of the present invention can be readily recycled or re-used, thus further being environmentally friendly. 
     The container of the present invention is simple and cost effective to fabricate and implement. The container of the present invention is compact, lightweight and rugged, and can easily accommodate any goods or cargo. The container of the present invention is suitable for bulk shipping and storage use, and is especially suitable for use in the military sector, where extreme environments including battlefield and urban warfare conditions are typically encountered. 
     In one embodiment of the present invention, there is provided a container for facilitating storage and transport of goods, which includes a top portion, a base portion and a sidewall portion, whereby the top and base portions are adapted for positioning the sidewall portion there between, wherein the top, base and sidewall portions further define an interior cavity, and a polyurea layer of sufficient thickness adhering to and coating at least the exterior areas of the top, base and sidewall portions. 
     Referring to  FIGS. 1 and 2 , a container  10  exhibiting high strength, lightweight, and insulating properties for safe storage and transport of goods and cargo, is shown for one embodiment of the present invention. The container  10  comprises a top panel or portion  12 , a base panel or portion  14  located opposite from the top panel  12 , a pair of opposing side panels or portions  16  and  18 , and a pair of opposing end panels or portions  20  and  22 . In this embodiment, only three types of panel components or portions are fabricated to implement the present invention. 
     The panels  12 ,  14 ,  16 ,  18 ,  20  and  22 , in combination, define on the interior side thereof an inner cavity  30  (see  FIG. 2 ) for securely accommodating and retaining goods and cargo, and include an outer surface on which adheres a layer  54  of a polyurea compound. The polyurea compound is generally a reaction product of an isocyanate component and a resin blend component comprising amine-terminated polymer resins and/or amine-terminated chain extenders. The polyurea layer  54  exhibits a sufficient thickness that adheres to and coats at least the exterior side of the panels  12 ,  14 ,  16 ,  18 ,  20  and  22 . 
     In a preferred embodiment of the present invention, the polyurea layer  54  is a unitary layer covering at least substantially the entire exterior surface of the container  10 . The polyurea layer  54  can extend across the joints between the joined panels  12 ,  14 ,  16 ,  18 ,  20  and  22  to enhance the structural integrity and strength and sealing properties of the container  10 . Optionally, the joint between the top panel  12  and the remainder of the container  10  may remain unsealed to facilitate ease of access. 
     The polyurea layer  54  is applied to the exterior side of the container  10 , and surface portions in contact with adjacent panels  12 ,  14 ,  16 ,  18 ,  20  or  22 . The application of the polyurea layer  54  can be made prior to assembly of the container  10  or after assembly. Optionally, the polyurea layer  54  can be applied to the interior sides of the panels  12 ,  14 ,  16 ,  18 ,  20  and  22 . To ensure proper adherence, the surface areas of the panels  12 ,  14 ,  16 ,  18 ,  20  and  22  is prepped and cleaned to remove contaminants. The polyurea layer  54  can be applied through any suitable means including spraying, dipping and the like. The polyurea layer  54  can further include a colorant to produce a desired color in the resulting container  10 . Examples of such colors include black, olive drab green, desert sand, Navy gray or any other colors desired. 
     In a preferred embodiment of the present invention, the thickness of the polyurea layer  54  is at least 0.030 inch, and more preferably, ranging from about 0.030 inch to 0.080 inch. The cured stress/tensile is at least 2800 psi, and preferably from about 2800 psi to 3000 psi. The cured elongation at 25° C. is at least 350%, and preferably from about 350% to 375%. The cured hardness is about 90 Shore A. The cured tear strength ply is at least 400 PLI, and the cured impact notch is at least 65 ft-lb/inch. An example of a suitable polyurea product is InstaCote M-25, marketed by InstaCote, Inc. of Erie, Mich. 
     The end portions of the side panels  16  and  18  and the end panels  20  and  20  are configured for interlocking engagement with one another to form a rigid joint exhibiting tensile strength (i.e., resistance to being pulled apart) therebetween. The top and base panels  12  and  14 , the side panels  16  and  18  and the end panels  20  and  22  are preferably composed of a foam-like polymer material, and more preferably selected from polystyrenes, polyethylenes, polypropylenes and combinations thereof. In a preferred embodiment of the present invention, the polymer material is in an extruded form. The panels  12 ,  14 ,  16 ,  18 ,  20  and  22  can be formed through, for example, sheet stamping and injection molding or hot wire cutting. The foam-like polymer material exhibits a density of at least 1.5 lbs per cubic foot, and preferably from about 2.8 to 3.2 lbs per cubic foot. The R or thermal value of the foam-like polymer material for the lower density material is at least 3.5 R-Value per every inch thickness. It is noted that as the density of the material increases, the R value decreases. It is further noted that as the density of the polymer material increases, the strength of the container  10  increases. 
     Optionally, the container  10  can further comprise at least one strap fasteners  15  in the form of a flat metal strapping for securing the closure of the container  10 , and a plurality of corner protectors  13  located at each corner areas of the container  10  to ensure proper placement of the strap fasteners  15 . It will be understood that the present invention is not limited to strap fasteners for securing closure, and that other securing mechanisms can also be used as known to one skilled in the art. 
     Each of the top and base panels  12  and  14 , the side panels  16  and  18 , and the end panels  20  and  22  are configured to fit and couple with one another to form a stable, and interlocking structure. As shown in  FIG. 2 , the top and base panels  12  and  14  include a stepped protrusion  24  centrally located on the interior side thereof. The stepped protrusion  24  slightly projects into the interior cavity  30  to provide a snug fit with the assembled structure of the side panels  16  and  18 , and the end panels  20  and  22  as will be described hereinafter. 
     The side panels  16  and  18 , each include a pin or projection  26  extending from opposing ends thereof. The end panels  20  and  22  each include a corresponding tail or groove  28  cut into the interior surface at the end portions thereof. The pins  26  and the tails  28  can be formed through any suitable means including, but not limited to, shaping and cutting via hot-wire foam cutting, 3- and 5-axis routers, or molding. The pins  26  of the side panels  16  and  18  are configured to snugly fit into the corresponding tails  28  of the end panels  20  and  22  to form a dovetail joint. The dovetail joint can be selected from a through dovetail joint, a half-blind dovetail joint, a sliding dovetail joint, a full-blind dovetail joint, and any combinations thereof. In a preferred embodiment, the dovetail joint is a sliding dovetail joint. 
     Referring to  FIGS. 3A-3D , the top and base panels  12  and  14  are shown for one embodiment of the present invention. Each of the top and base panels  12  and  14  is rectangular in shape, and includes the stepped protrusion  24  located central on the interior side thereof. The polyurea layer  54  is generally applied to coat a top surface  32 , edge surfaces  34  and a flange surface  36  of the top and base panels  12  and  14 . The stepped protrusions  24  of the top and base panels  12  and  14  provide a snug fit and sealing contact with the assembled side panels  16  and  18  and the end panels  20  and  22  as shown in  FIG. 1 . Optionally, a bead of sealant can be applied to edge portions  38  along the periphery of the stepped protrusion  24  to further enhance sealing contact and provide a small interference fit. 
     Referring to  FIG. 4A-4C , the side panels  16  and  18  are shown for one embodiment of the present invention. Each of the side panels  16  and  18  is rectangular in shape, and includes the pins or projections  26  extending from opposing ends thereof. The polyurea layer  54  is generally applied to coat an outer surface  40  and an edge surface  42  of the side panels  16  and  18 . Optionally, the polyurea layer  54  can be applied to coat an inside surface  44 . 
     The pins  26  of the side panels  16  and  18  are adapted to fit into and mate with the corresponding tails  28  of the end panels  20  and  22  (see  FIG. 5B ) to form a snug fit joint therebetween. The pins  26  and the tails  28  are trapezoidal in shape, and configured to fit together with no gap therebetween so that the joint interlocks tightly with no movement. The resulting joint forms a sliding dovetail joint. The angle of the slope of the trapezoid can range depending on the hardness of the side panels  16  and  18  and the end panels  20  and  22 , and the slope can range from 1:6 to 1:8, and preferably 1:7. 
     Referring to  FIGS. 5A and 5B , the end panels  20  and  22  are shown for one embodiment of the present invention. Each of the end panels  20  and  22  is rectangular in shape, and includes the tails  28  located proximate the ends on the interior side thereof. The end panels  20  and  22  further include an outer surface  46 , side surfaces  48 , top and bottom surfaces  50 , and an inside surface  52 . The polyurea layer  54  is generally applied to coat the outer surface  46 , the side surfaces  48 , the top and bottom surfaces  50  of the end panels  20  and  22 . Optionally, the polyurea layer  54  can be applied to coat the inside surface  52 . The tails  28  of the end panels  20  and  22  are each in the form of a straight groove extending between the top and bottom surfaces  50 , and are adapted to fit into and mate with the corresponding pins  26  of the side panels  16  and  18  (see  FIGS. 4A to 4C ) to form a snug fit joint therebetween. 
     With references to  FIGS. 1 through 5B , the container  10  can be readily assembled in a simple manner. The top panel  12  is prepped and cleared of contaminants on the surface, and may be pre-coated with the polyurea layer  54  over the areas previously described above. The top panel  12  is set aside to allow the polyurea layer  54  to properly dry and cure. The base panel  14  is placed flat with the stepped protrusion  14  extending upward. Each of the end panels  20  and  22  are placed on the flange portion  36  and abutting against the edge portion  38  of the base panel  14 , respectively, with the tails  28  facing towards one another. Each of the side panels  16  and  18  are placed on the flange portion  36  of the base panel  14  with the pins  26  sliding into the corresponding tails  28  of the end panels  20  and  22 . 
     Once assembled, the panels  14 ,  16 ,  18 ,  20  and  22  form a bottom structure of the container  10 . The bottom structure of the container  10  is prepped and cleared of contaminants on the surface. The polyurea layer  54  is applied as a unitary coating to the exterior portions of the bottom structure of the container  10 . The polyurea layer  54  securely retains the corresponding panels  14 ,  16 ,  18 ,  20  and  22  to one another, thus enhancing tensile strength and rigidity therebetween. The coated bottom structure is set aside to allow the polyurea layer  54  to properly dry and cure. 
     Once the polyurea layer  54  is fully cured, the pre-coated top panel  12  is placed on top of the bottom structure formed by the coupled bottom, side and end panels  14 ,  16 ,  18 ,  20 , and  22 , with the stepped protrusion  24  inserted into the interior cavity  30  to form the container  10 . Optionally, a bead of sealant such as silicone can be applied around the sealing edge portions  38  of the top and base panels  12  and  14  to provide a small interference fit to seal the container  10  and/or along the inside seams or joints of the container  10  after assembly. The corner protectors  13  are placed at the corner portions of the top and base panels  12  and  14 , and the strap fasteners  15  are affixed around the container  10  on the corner protectors  13  for securing closure of the container  10 . 
     EXAMPLE 
     Test Study and Results for Container of the Present Invention 
     A test study was implemented to test and evaluate four test containers (two containers, one of each density tested to ASTM D 4169 DC-18, and two containers one of each density stack tested to 30,000 lb or failure whichever occurs first). The test containers were constructed and packaged as specified below. 
     A sample size of four test containers (two containers for ASTM D 4169 DC-18 Schedule H and F testing, and two containers for ASTM D 4169 DC-18 Schedule B stack to failure testing) was delivered in a new untested condition to the PSCC Testing Lab for ASTM D4169 Distribution Cycle 18 testing. 
     These test containers included a bead of silicon added to the test containers top where it contacts the inside edge of the test container when closed. The test containers were designed for use as a Level A shipping container for ground and air transportation of Carrier Assay Assemblies, Assay Strips. 
     The test containers were developed in accordance with military handling requirements to include: preservation, packing, unitization, and marking. The Carrier Assay Assemblies required passive temperature control for shipment. Carrier Assay Assemblies are sensitive to extreme temperature conditions including freezing temperatures and elevated temperatures. One of the requirements for the test containers is protection of the Carrier Assay Assemblies from extreme temperature for about 72 hours. 
     Two test containers of different densities were packaged at the testing facility and banded. The test containers were pre-numbered by the customer (ID and density numbers) and used throughout the test for identification of results. The test container ID, dimensions, and weights are shown in Table 1 below. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Test Container  
                 Exterior Container 
                   
               
               
                   
                 ID Number 
                 Dimensions 
                 Density 
               
               
                   
                   
               
             
            
               
                   
                 1 
                 40 × 23½ × 14½ 
                 4# 
               
               
                   
                 2 
                 40 × 23¼ × 14½ 
                 3# 
               
               
                   
                 3 
                 40 × 23½ × 14½ 
                 4# 
               
               
                   
                 4 
                 37¼ × 21 × 13 3/4  
                 3# 
               
               
                   
                   
               
               
                   
                 *Note: All dimensions are in inches 
               
               
                   
                 All weights are gross and in pounds except 1 and 4 which are tare weights 
               
            
           
         
       
     
     The Carrier Assay Assemblies were packaged and cushioned in their individual fiberboard containers, and then in water vapor proof bags along with desiccant packs. A temperature indicator was placed in the interior of the containers to alert whether the Carrier Assay Assemblies has been exposed to temperature environments beyond the limits of the Carrier Assay Assemblies. The individually packed Carrier Assay Assemblies were placed in a 3 to 4-lb density polyethylene containers having a removable lid. The exterior surfaces and interior top edges of the test containers were sprayed with a commercially available polyurea product. The inside surface of the lid and interior of the packaging remained unsprayed in its original extruded condition. A bead of silicon was placed around the entire inside of the top edge of the removable top, where contact is made with the inside edge of the test container when closed. Closure/sealing was accomplished using three pieces of ¾″×0.023″ steel banding. 
     All testing was performed in the PSCC container laboratory with ambient conditions ranging from 70 to 74 degrees Fahrenheit and 43 to 56 percent Relative Humidity unless stated otherwise. A Tenney Environmental Walk-in T/H chamber, Model WITR, Calibration expiration date 14 Mar. 2008, was used for conditioning. Temperature and humidity were recorded using a Honeywell DR 4300 chart recorder and controlled with a Tenney Versa Tenn III controller. 
     The test containers were inspected for damage as received prior to testing. The number 2 and 3 test containers used for schedule H and F testing were packaged (gross weight of 57 lb) by the customer according to an established government SPI at the PSCC container laboratory. On completion of packaging, the test containers were placed into a T/H walk-in chamber and conditioned in accordance with ASTM D 4332, in standard conditions (73.4° F.±1.4°, 50% RH±5%) for a minimum of 72 hours prior to testing. 
     The test containers were tested in accordance with requirements of ASTM D 4169-05, schedules H, F, and B per Distribution Cycle 18, Quality Assurance Level I (Level A Military packaging per MIL-STD-2073-1D), Acceptance criteria 1 for Small Shipping Containers. Small shipping containers are defined as one having no edge dimension or diameter over 60 inches and a gross weight of 150 lb or less. The test schedule is shown in Table 2 below. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                 Distribution 
                 Sequence 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Cycle 
                 First 
                 Second 
                 Third 
               
               
                   
                   
               
               
                   
                 18 
                 Schedule H 
                 Schedule F  
                 Schedule B 
               
               
                   
                   
                   
                   
                 (Destructive) 
               
               
                   
                   
                   
                   
                 See note 
               
               
                   
                   
               
               
                   
                 Note: The third sequence was added to the test requirements per the customers request and was not part of the original DC-18. The containers used for the DC-18 testing were inspected for condition of container, and banding, after sequence two, then opened and inspected for moisture/water leakage, and rated. 
               
            
           
         
       
     
     The acceptance criteria at the completion of the test included compliance with Criterion 1 of ASTM D 4169 and protection of the Carrier Assay Assemblies against damage. Although both of these test containers have a re-usable application for other products they will not be used as re-usable test containers in the JBPDS life cycle. Minor damage or minor blemishes to the test containers may be allowed at the discretion of the government as long as these conditions do not affect the performance of the test container or its expected life as a non-reusable test container as used in this application. Pass, Fail ratings were given for each test. 
     The summary of the tests conducted and the results are shown in Table 3 below. 
     
       
         
           
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Test Performed 
                 Results of Test 
               
               
                   
               
             
            
               
                 Environmental Hazards test (ASTM D 4169 
                 Pass 
               
               
                 Schedule H first sequence) 
                   
               
               
                 Loose load Vibration test (ASTM D 4169 
                 Pass 
               
               
                 Schedule F fifth sequence) 
                   
               
               
                 Warehouse Stacking test (Modified ASTM D 4169  
                 N/A for comparison 
               
               
                 Schedule B fifth sequence) (Destructive) 
                 only 
               
               
                   
               
            
           
         
       
     
     Testing procedures were conducted on the loaded test containers in the following sequence with results included for each procedure. 
     Schedule H, (Environmental Hazards) Fourth Sequence determines the susceptibility of the total pack to the effects of moisture, temperature shock, or the combined effects of cyclic exposure. The Environmental Hazards test was implemented over a four-day testing period. A Tenney Environmental walk-in chamber with a Watlow 920 series controller and Honeywell model 9500 chart recorder was used to accomplish the temperature exposure of the testing, and Packaging Rain Room (with water recycling system capable of up to 6 inches of rainfall per hour). 
     The environmental test was performed in accordance with ASTM D 4169 para 15.1-15.2 and Test Method D 951-99, where spray intensity of; 4+1 inches per hour is used for Assurance Level I. Rainfall levels were recorded using a LaCrosse model WS-7048U Rain. Meter (self calibrating). Testing was performed at ambient conditions of 70°-74° F. &amp; 43-56% RH. The test levels used to perform this test is shown in Table 4 below. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Environmental Test Levels 
               
            
           
           
               
               
            
               
                   
                 DC-18 Assurance Level II 
               
            
           
           
               
               
               
            
               
                 Temperature (° F.) 
                 Water Spray 
                 Duration Hours 
               
               
                   
               
            
           
           
               
               
               
            
               
                 130 
                   
                 16 
               
               
                 60 
                 X 
                 2 
               
               
                 −10 
                   
                 2 
               
               
                 130 
                 X 
                 2 
               
               
                 60 
                 X 
                 2 
               
               
                 50 
                   
                 16 
               
               
                 130 
                   
                 4 
               
               
                 60 
                 X 
                 2 
               
               
                 50 
                   
                 2 
               
               
                 130 
                   
                 16 
               
               
                 60 
                 X 
                 2 
               
               
                 −10 
                   
                 2 
               
               
                 50 
                   
                 3 
               
               
                 130 
                   
                 16 
               
               
                   
               
            
           
         
       
     
     After the environmental testing was completed the test containers were weighed and examined for damage. The average weight gain per container after environmental exposure was approximately 4 lb. The test containers were palletized (for ease of handling/transportation) on their sides (to check for excessive water inside) prior to vibration testing. Although the test containers leaked at the sealed top edges there was no excessive water runout from inside. A PASS was given for this test. 
     The test levels and test methods for Schedule F (Loose Load Vibration) Fifth Sequence of the distribution cycle were intended to determine the ability of shipping units to withstand the vertical vibration environment during transport. The test levels and methods account for the magnitude, frequency range, duration, and direction of vibration. The Loose Load Vibration test was implemented at ambient conditions of 70° F. &amp; 56% RH. Vibration tests were conducted on the loaded test container as specified in ASTM D 999-01 Method A2, Repetitive Shock Test (Rotary Motion). 
     This test was conducted on an L.A.B. Model 2000V, 2,000-pound capacity and Model 1250V, 1250-pound capacity vibration table, with the double amplitude displacement of the vibration table fixed at one inch. The test ran for a total of three hours (per test container). The test containers were vibrated for 90 minutes in the longitudinal orientation (test container end to left), then rotated 90 degrees and vibrated for 90 minutes in the lateral orientation (test container end to front). Table 5 shows the RPM/Hz required for liftoff of the different test containers. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Test 
                   
                   
                   
               
               
                   
                 container ID 
                 Container 
                 RPM/Hz 
                 RPM/HZ 
               
               
                   
                 number 
                 Nomenclature 
                 Longitudinal 
                 Lateral 
               
               
                   
                   
               
             
            
               
                   
                 2 
                 Poly 
                 240/4 
                 235/3.91 
               
               
                   
                 3 
                 Poly 
                 240/4 
                 235/3.91 
               
               
                   
                   
               
            
           
         
       
     
     There was minor scuffing of all four tested containers bottoms caused by the rotary motion of the vibration table and friction of the package on the table&#39;s platform. There was no other visible damage. A PASS rating was given for this test. 
     At the completion of sequence two, the two tested were opened and assessed for damage. When opened and unpacked, test container  2  was dry inside but there was a slight feeling of moisture present on the bottom of the intermediate packagings. The intermediate packagings were damage free and were not opened due to their condition. Upon opening and unpacking it was concluded that the seals (silicon bead) on both test containers had slight leaks contributing to the 4 lb gain in container weight (test container  3  was a bit damper than test container  2  and had a few small droplets of water inside due to the environmental exposure testing). The outside of the test container showed no splits or other damage as did the inside. Both test containers were given a PASS rating at test completion. 
     The purpose of Schedule B, Warehouse Stacking Third Sequence (destructive) was to determine the structural strength of the test containers in relationship to each other. The test container was manufactured from polyethylene materials and coated with a polyurea material. The test container with the sprayed on polyurea coating was proposed to reduce cost, provide better water-proof protection, provide thermal protection (when required) and reduce weight of the current pack. This test container has military applications far beyond the current configuration. 
     In the Stacking Test, a static load of 30,000 lb was placed on each test, container (empty) until failure. The test was implemented for strength comparison only. This test was conducted on a Gaynes Model 30KCT Compression Tester with a 30,000 pound compressive limit. Calibration expiration date is April 2007. Testing was performed at ambient conditions of 72° F. &amp; 43% RH. Stacking test of the test containers was performed in accordance with Test Method ASTM D 642-00 and ASTM D 4169-04a para 11.3. The test container ID and stack weights used for testing are shown in Table 6 below. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Test container 
                 Exterior Container  
                 Container 
                 Stack 
               
               
                   
                 ID Number 
                 Dimensions 
                 Density 
                 (weight) 
               
               
                   
                   
               
             
            
               
                   
                 1 
                 37¼ × 21 × 13¾ 
                 4# 
                 30,000 
               
               
                   
                   
                   
                   
                 lb 
               
               
                   
                 4 
                 37¼ × 21 × 13¾ 
                 3# 
                 30,000 
               
               
                   
                   
                 Complete sprayed on 
                   
                 lb 
               
               
                   
                   
                 coating inside and 
                   
                   
               
               
                   
                   
                 outside 
               
               
                   
                   
               
               
                   
                 Note: All dimensions are in inches 
               
            
           
         
       
     
     As shown in Table 7 below, the test containers reached peak loads of 12,508 lb and 17,490 lb before losing structural strength, causing the sidewalls to bow. The lid of the test containers was critical in adding to its strength absorbing most of the compression (approx. 0.75 inches) observed during testing. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Test 
                   
                   
                   
                   
               
               
                 container ID  
                 Exterior Container 
                 Container 
                 Peak Load 
                 Deflection 
               
               
                 Number 
                 Dimensions (in.) 
                 Density 
                 (lbs.) 
                 (in.) 
               
               
                   
               
             
            
               
                 1 
                 371/4 x 2 1 x 13% 
                 4# 
                 12,508 
                 .95 
               
               
                 4 
                 371/4 x 2 1 x 13% 
                 3# 
                 17,490 
                 .85 
               
               
                   
               
            
           
         
       
     
     It can be concluded from the results of testing that there is still a small problem sealing the test container tops but considerable progress was made as indicated by the weight gain seen during environmental exposure testing which showed less than half the weight gain experienced during testing on similar container without the silicon bead (seal) added. 
     The polyurea coating added to the interior top edge added structural strength to the test container preventing the inner cracking and separations seen in the previous testing of the same container design during stack to failure of the container. The test containers used in the packaging of the Carrier Assay Assemblies, Assay Strips are durable and would be an acceptable replacement for cleated panel board boxes as a shipping container used for shipment of the parts, thus reducing the cost of packaging and shipping to the government. Recommendations include different placement of the silicon beading on the test container tops along with a different banding pattern to prevent the induction of water/moisture to the interior of the test containers. 
     The forgoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying claims, that various changes, modifications, and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims. For example, side panels  16  and  18  can alternatively be square in shape, as can be the end panels  20  and  22 , and the top and base panels  12  and  14 .