Abstract:
A panel includes a sheet of heat-shrinkable polymer material and a packet coupled to the sheet. The packet contains a reactant that is activated in response to the sheet shrinking.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to articles for cooling temperature-sensitive items, and more particularly to articles that experience an endothermic reaction when heated to a predetermined temperature. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many portable electronic devices can be adversely affected by heat. When electronic devices are stored in high heat environments, such as the interior of an automobile on a hot day, they may suffer significant damage that compromises the functionality of the device as well as any stored data. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention provides, in one aspect, a panel including a sheet of heat-shrinkable polymer material and a packet coupled to the sheet. The packet contains a reactant that is activated in response to the sheet shrinking. 
         [0004]    The invention provides, in another aspect, a container including a compartment in which a temperature-sensitive item is receivable and a panel in thermal communication with the compartment. The panel includes a sheet of heat-shrinkable polymer material and a packet coupled to the sheet. The packet contains a reactant that is activated in response to the sheet shrinking The reactant undergoes an endothermic reaction when activated to remove heat from the compartment. 
         [0005]    Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a cooling panel in accordance with an embodiment of the invention, illustrated in an inactivated state. 
           [0007]      FIG. 2  is an enlarged perspective view of a portion of the cooling panel of  FIG. 1   
           [0008]      FIG. 3  is a perspective view of the cooling panel illustrated in an activated state. 
           [0009]      FIG. 4  is an enlarged perspective view of a portion of the cooling panel of  FIG. 3 . 
           [0010]      FIG. 5  is a perspective view of an exemplary container incorporating the cooling panel of  FIG. 1 . 
       
    
    
       [0011]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION 
       [0012]      FIG. 1 , illustrates a cooling panel  10  including first and second interconnected sheets  14 ,  18  of a heat-shrinkable polymer material. The interconnected sheets  14 ,  18  may define a self-corrugating polymer panel such as those described in U.S. Patent Application Publication Nos. 2014/0087145, 2014/0087146, and 2014/0087147, the entire contents of all of which are incorporated herein by reference. 
         [0013]    Before assembling the cooling panel  10 , each of the sheets  14 ,  18  is uniaxially stretched to impart direction or orientation in the polymer chains. The sheets  14 ,  18  are oriented so that the stretched direction of the first sheet  14  is generally perpendicular to the stretched direction of the second sheet  18 . A radio frequency (RF) or other suitable welding process is used to create weld spots  22  that permanently bond the sheets  14 ,  18  at evenly-spaced intervals. 
         [0014]    With reference to  FIGS. 1 and 2 , the cooling panel  10  also includes reactant packets  26  located between the sheets  14 ,  18  and interconnected to the sheets  14 ,  18  by the weld spots  22 . The reactant packets  26  contain a first, liquid reactant  30  and a second, powdered reactant  34  enclosed within a frangible capsule  38  that is immersed in the first reactant  30 . In the illustrated embodiment, the first reactant  30  is water and the second reactant  34  is ammonium nitrate. As described in greater detail below, when the two reactants  30 ,  34  mix, they produce an endothermic reaction: 
         [0000]      NH 4 NO 3(8) +Heat→NH 4   +   (aq) +NO 3   −   (aq) .
 
         [0015]    This reaction cools the panel  10  and its surroundings. In other embodiments, the second reactant  34  can be any other substance suitable for producing an endothermic reaction when mixed with water. For example, the second reactant  34  may include calcium ammonium nitrate or urea. Alternatively, the first reactant  30  may include any other liquid or gel, and the second reactant  34  may include any other substance suitable for producing an endothermic reaction when mixed with the first reactant  30 . 
         [0016]    With reference to  FIGS. 3 and 4 , when the cooling panel  10  is heated to a predetermined temperature, the first and second sheets  14 ,  18  shrink along orthogonal axes, creating undulations  42  in each of the sheets  14 ,  18  between adjacent weld spots  22 . This deformation causes the frangible capsules  38  to rupture and mixes the first and second reactants  30 ,  34  to trigger the endothermic reaction ( FIG. 4 ). 
         [0017]    In operation, the cooling panel  10  begins shrinking from its inactivated state shown in  FIGS. 1 and 2  to the activated state shown in  FIGS. 3 and 4  when it is exposed to a predetermined temperature (e.g., about 120 degrees Fahrenheit). As the interconnected sheets  14 ,  18  shrink, the weld spots  22  are displaced relative to each other, causing the capsules  38  to rupture. The reactant  34  (e.g., ammonium nitrate) empties from the capsule  38  and mixes with the reactant  30  (e.g., water), beginning the endothermic reaction. As the reaction progresses, the temperature of the cooling panel  10  decreases substantially to cool the ambient surroundings of the cooling panel  10 . In the illustrated embodiment, the temperature of the cooling panel  10  may be reduced by about 85 degrees Fahrenheit. 
         [0018]      FIG. 5  illustrates a container  50  having a compartment  54  in which a temperature-sensitive item (e.g., a laptop, music player, hard drive, cellular phone, etc., not shown) is receivable. In the illustrated embodiment, the container  50  is a briefcase; however, the container  50  may be a laptop sleeve, backpack, suitcase, or any other container suitable for storing or transporting a temperature-sensitive item. One or more cooling panels  10  may be inserted into the container  50  such that they are in thermal communication with the compartment  54 . 
         [0019]    Should the container  50  with the enclosed device be exposed to a high temperature (e.g., in a closed vehicle) that might otherwise damage or cause the device to malfunction, the one or more cooling panels  10  in the container  50  may be activated in the manner described above to thereby cool the compartment  54  and the device. Once activated, the one or more cooling panels  10  can be removed and replaced with new, inactivated cooling panels  10 . 
         [0020]    Various features of the invention are set forth in the following claims.