Self-cooling containers and wraps

Abstract

Self-cooling materials, such as food containers for transporting perishable food items, and methods for producing and using the materials are disclosed. The materials include a reactant adapted to produce an endothermic reaction upon hydration of the reactant by ambient water vapor.

1 . A self-cooling container comprising at least one panel defining an interior space for containing a product therein, the panel having an internal surface defining the interior space and an external surface disposed outwardly of the internal surface, and at least a portion of the at least one panel comprises a reactant adapted to produce an endothermic reaction upon hydration of the reactant by ambient water vapor. 
     
     
         2 . The container of  claim 1 , wherein the at least one panel comprises:
 a first polymer film forming the internal surface;   a second polymer film forming the external surface, the second polymer film being moisture permeable; and   the reactant is disposed between the first polymer film and the second polymer film.   
     
     
         3 . (canceled) 
     
     
         4 . The container of  claim 1 , wherein the at least one panel comprises:
 a material layer having a first surface defining the internal surface of the at least one panel, and a second surface external to the first surface; and   the reactant is disposed on at least a portion of the second surface of the material layer.   
     
     
         5 . The container of  claim 1 , wherein the at least one panel comprises:
 a first material layer having a first surface defining the internal surface of the at least one panel, and a second surface external to the first surface; and   a cooling layer disposed adjacent the second surface of the first material layer, wherein the cooling layer comprises the reactant.   
     
     
         6 . The container of  claim 5 , wherein:
 the cooling layer comprises a layer of the reactant disposed between a first polymer film and a second polymer film;   at least one of the first polymer film and the second polymer film comprises a moisture-permeable film; and   the moisture-permeable film is disposed outwardly away from the first material layer and defines the external surface of the at least one panel.   
     
     
         7 . The container of  claim 6 , wherein each of the first polymer film and the second polymer film individually comprises: poly lactic acid (PLA), co-poly lactic acid/glycolic acid (PLGA), cellulose, starch, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, nylon, polyolefin, ethylene-vinyl acetate, ethylene-vinyl alcohol, ethylene-acrylic acid, polystyrene, polyvinyl alcohol, polyethylene terephthalate, polyethylene naphthalate, polycarbonates, cellulose polymers, polyamide, polyacrylonitrile, acrylonitrile/styrene, or any combination thereof. 
     
     
         8 . The container of  claim 6 , wherein the moisture-permeable film comprises a porous film. 
     
     
         9 .- 12 . (canceled) 
     
     
         13 . The container of  claim 1 , wherein the reactant comprises at least one water-soluble salt that contains at least one of potassium, sodium, ammonium, and nitrogen. 
     
     
         14 . The container of  claim 13 , wherein the at least one water-soluble salt is a non-toxic salt selected from a group comprising: potassium bromide (KBr), potassium chloride (KCl), potassium iodide (KI), potassium nitrate (KNO 3 ), potassium sulfate (K 2 SO 4 ), sodium bromide dihydrate (NaBr.2H 2 O), sodium chloride (NaCl), sodium chlorate (NaClO 3 ), sodium iodide diydrate (NaI.2H 2 O), sodium perchlorate (NaClO 4 ), sodium acetate trihydrate (NaC 2 H 3 O 2 .3H 2 O), sodium thiosulfate pentahydrate (Na 2 S 2 O 3 .5H 2 O), ammonium bromide (NH 4 Br), ammonium nitrate (NH 4 NO 3 ), ammonium chloride (NH 4 Cl), urea (CO(NH 2 ) 2 ), and ammonium phosphate ((NH 4 ) 3 PO 4 ). 
     
     
         15 . (canceled) 
     
     
         16 . The container of  claim 1 , wherein the reactant comprises at least one dehydrated hydrogel. 
     
     
         17 . The container of  claim 16 , wherein the dehydrated hydrogel comprises a sol gel, a silicone gel, a polyacrylamide gel, a polyvinyl alcohol gel, a polyacrylate gel, an acrylate polymer, agarose, alginate, methylcellulose, hyaluronan, or any combination thereof. 
     
     
         18 . The container of  claim 1 , wherein the reactant comprises a thermal buffer material. 
     
     
         19 . The container of  claim 18 , wherein the thermal buffer material comprises a phase-change material selected from the group consisting of salt hydrates, paraffin and fatty acids. 
     
     
         20 .- 22 . (canceled) 
     
     
         23 . The container of  claim 1 , wherein the reactant comprises a plurality of components capable of undergoing an endothermic reaction upon solvation of at least one of the plurality of components. 
     
     
         24 . The container of  claim 23 , wherein a first component of the plurality of components comprises an organic acid and a second component of the plurality of components comprises a carbonate. 
     
     
         25 . The container of  claim 24 , wherein the organic acid comprises citric acid, acetic acid, propanoic acid, tartaric acid, succinic acid, formic acid, fumaric acid, lactic acid, or any combination thereof. 
     
     
         26 . The container of  claim 24 , wherein the carbonate comprises calcium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, lithium carbonate, or any combination thereof. 
     
     
         27 .- 53 . (canceled) 
     
     
         54 . A method for maintaining a temperature of a food item, the method comprising:
 disposing a cooling material adjacent at least a portion of the food item, the cooling material comprising a reactant adapted to produce an endothermic reaction upon hydration of the reactant with ambient water vapor;   storing the food item in a cold, dry environment;   removing the food item from the cold, dry environment; and   exposing the cooling material to the ambient water vapor to hydrate the reactant, initiate the endothermic reaction and maintain the temperature of the food item.   
     
     
         55 . (canceled) 
     
     
         56 . The method of  claim 54 , wherein the disposing comprises disposing a cooling material covered by a removable, moisture impermeable wrap, and the exposing comprises removing the moisture impermeable wrap to expose the cooling material to the ambient water vapor to hydrate the reactant and initiate the endothermic reaction. 
     
     
         57 . (canceled) 
     
     
         58 . The method of  claim 54 , wherein the reactant comprises at least one soluble salt capable of undergoing an endothermic reaction caused by dissolution of the at least one soluble salt during hydration, and the exposing comprises exposing the at least one soluble salt to the ambient water vapor to at least begin to dissolve the at least one soluble salt and initiate the endothermic reaction. 
     
     
         59 . The method of  claim 58 , wherein the at least one soluble salt is a non-toxic salt selected from a group comprising: potassium bromide (KBr), potassium chloride (KCl), potassium iodide (KI), potassium nitrate (KNO 3 ), potassium sulfate (K 2 SO 4 ), sodium bromide dihydrate (NaBr.2H 2 O), sodium chloride (NaCl), sodium chlorate (NaClO 3 ), sodium iodide diydrate (NaI.2H 2 O), sodium perchlorate (NaClO 4 ), sodium acetate trihydrate (NaC 2 H 3 O 2 .3H 2 O), sodium thiosulfate pentahydrate (Na 2 S 2 O 3 .5H 2 O), ammonium bromide (NH 4 Br), ammonium nitrate (NH 4 NO 3 ), ammonium chloride (NH 4 Cl), urea (CO(NH 2 ) 2 ), and ammonium phosphate ((NH 4 ) 3 PO 4 ). 
     
     
         60 . The method of  claim 58 , wherein the at least one soluble salt is mixed with at least one dehydrated hydrogel, and the exposing further comprises exposing the hydrogel to the ambient water vapor to hydrate the hydrogel to form a gel with the at least one dissolved soluble salt to retain the at least one dissolved salt in the cooling material. 
     
     
         61 . The method of  claim 60 , wherein dehydrated hydrogel comprises a sol gel, a silicone gel, a polyacrylamide gel, a polyvinyl alcohol gel, a polyacrylate gel, an acrylate polymer, agarose, alginate, methylcellulose, hyaluronan, or any combination thereof. 
     
     
         62 . The method of  claim 54 , wherein the reactant comprises a plurality of components capable of undergoing an endothermic reaction upon solvation of at least one of the plurality of components, and the exposing comprises solvating the at least one of the plurality of components to initiate the endothermic reaction between the plurality of components. 
     
     
         63 . The method of  claim 62 , wherein a first component of the plurality of components comprises an organic acid selected from the group consisting of citric acid, acetic acid, propanoic acid, tartaric acid, succinic acid, formic acid, fumaric acid and lactic acid and a second component of the plurality of components comprises a carbonate selected from the group consisting of calcium carbonate, sodium carbonate potassium carbonate, magnesium carbonate and lithium carbonate. 
     
     
         64 . (canceled) 
     
     
         65 . (canceled) 
     
     
         66 . The method of  claim 54 , wherein:
 The disposing comprises disposing a cooling material further comprising a phase-change material configured to provide an at least partially solid thermal barrier upon hydration and cooling of the phase-change material; and   the method further comprises, upon exposure to the ambient water vapor, hydrating the phase-change material to produce an at least partial phase change the phase-change material to form a thermal barrier to retain cooling of the food item.   
     
     
         67 . The method of  claim 66 , wherein the phase-change material comprises paraffin, capric acid, lauric acid, palmitic acid, a stearic fatty acid, hydrated sodium acetate, calcium chloride hexahydrate, potassium fluoride tetrahydrate, a eutectic salt mixture, or any combination thereof. 
     
     
         68 .- 108 . (canceled)