Patent Publication Number: US-2015059729-A1

Title: Package for oxygen activated portable heater

Description:
CROSS REFERENCE APPLICATIONS TO RELATED APPLICATIONS 
     The present application is a conversion, and claims priority of pending U.S. Provisional Patent Application Ser. No. 61/871,972 field Aug. 30, 2013, the entirety of which is incorporated herein. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a package for a heater that uses oxygen as a fuel source for a reaction that produces heat. 
     BACKGROUND OF THE INVENTION 
     Portable flameless heaters are currently used in a variety of applications, for example heating comestible items. For example the United States Army uses a flameless ration heater (FRH) rather than a portable camp stove to heat a pre-packaged MRE (meal ready to eat) eight-ounce (approximately 227 grams) field ration. The FRH consists of a super-corroding magnesium/iron mixture sealed in a waterproof pouch (total FRH weight is approximately 22 grams). To operate a FRH, the pouch is opened into which the MRE is inserted, and approximately 58 grams of water is added to a fuel-containing portion of the FRH pouch surrounding the MRE to initiate the following reaction: 
       Mg+2H 2 O/EMg(OH) 2 +H 2    
     Based upon the above reaction of the fuel, the MRE temperature is raised by approximately 100° F. in less than 10 minutes. The maximum temperature of the system is safely regulated to about 212° F. by evaporation and condensation of water vapor. 
     The current FRH, while effective for its intended purpose, produces hydrogen gas as a byproduct, generating safety, transportation, storage and disposal concerns, and making it less suitable for use in consumer sector applications where accidental misuse could lead to fire or explosion. 
     Also, the water required for reaction, in addition to being heavy and spacious, is typically obtained from a soldier&#39;s drinking water supply, which is often limited. Addition of the water can also be an inconvenient additional step in the process of activating the FRH. 
     Self-heating food packaging products are also available in the consumer market. These products use the heat of hydration from mixing “quicklime” (calcium oxide) and water (CaO+H 2 O=Ca(OH) 2 ) which does not generate hydrogen. With water present the peak temperature is similarly limited to 212° F. but even neglecting the weight of packaging and water, the specific energy of the system is low (approximately 1.2 kJ per gram of CaO). These and other self-contained systems must also provide some means of mixing the segregated reactants adding further complexity and bulk. Measurements on some commercial self-heating packaged food products are shown in Table 1. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Food product (net) 
                 Total package (gross) 
                 Specific  
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Weight  
                 Volume 
                 Weight  
                 Volume 
                 energy of  
               
               
                   
                 (g) 
                 (ml) 
                 (g) 
                 (ml) 
                 heater (kJ/g) 
               
               
                   
               
               
                 Coffee 
                 300 
                 295 
                 551 
                 600 
                 0.34 
               
               
                 Beef stew 
                 425 
                 481 
                 883 
                 963 
                 0.13 
               
               
                   
               
            
           
         
       
     
     While quicklime based heaters may offer greater safety than the Mg based heaters, quicklime heaters significantly lower specific energy and cause the weight and size of the heater to approach that of the object being heated, reducing portability. 
     In addition to the water-based heaters described above, it is known to utilize oxygen-based heaters. Oxygen-based heaters, such as those described in U.S. Pat. Nos. 5,984,995, 5,918,590 and 4,205,957, have certain benefits over water-based heaters. 
     First, oxygen-based heaters do not require the addition of water to generate heat. Second, because the oxygen-based heater generates heat only in the presence of oxygen, the reaction may be stopped by preventing oxygen access and then restarted at a later time. 
     Despite the advantages of oxygen-based heaters, there is still a need for improved oxygen-based heaters, as well as methods of manufacturing same. 
     In addition, it would be beneficial to use such an oxygen-based heater in the heating of an object such as sanitary wipes and/or baby wipes, as well as utilize such heaters in a housing for heating the sanitary wipes/or baby wipes. 
     To this end, the applicant&#39;s assignee of the present invention has provided oxygen-based heater and various packages for same. See, e.g., U.S. patent application Ser. Nos. 12/376,927 and 12/874,338 (filed on Feb. 9, 2009 and Sep. 2, 2010, respectively) both of which are incorporated herein by reference in their entirety; see also, U.S. patent application Ser. Nos. 11/486,400 and 12/711,963 (filed on Jul. 12, 2006 and Feb. 24, 2010, respectively) both of which are incorporated herein by reference in their entirety. 
     The disclosed heaters and packages are successful at providing an oxygen based heater and/or package for same. However, there are benefits that can be obtained from improvising on the disclosed heaters and packages. These benefits can provide for more efficient heaters; better packaging; easier manufacturing; less expensive manufacturing costs. 
     The present invention is directed to providing improvements that can provide these benefits, as well as other benefits. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, the present invention is directed towards a heater package with improved reactant control by providing barrier layers, diffusing layers, thermal transfer layers, and/or insulation. 
     In the preferred embodiment of the invention, a heater package is associated with an object to be heated. The heater package comprises an inner layer defining a cavity, an oxygen activated heater positioned within the cavity, an outer layer external to the cavity, wherein the inner and outer layers enable controlled ingress of oxygen toward and into the oxygen activated heater positioned within the cavity, and, wherein at least a portion of the outer layer is associated with an object to be heated. 
     In one aspect of the present invention, a temperature indicator is associated with at least one of the heater and an object being heated. It is contemplated that the temperature indicator comprises thermally activated graphics associated with at least one of the outer layer and a remote handheld device. 
     In the preferred embodiment of the invention, the oxygen activated heater has a geometry that generally conforms to the geometry of the inner and outer layers. For example, the heater may have at least one surface having a corrugated configuration. It is contemplated that the corrugated surface is associated with a temperature indicator. 
     In a preferred embodiment of the invention, the oxygen activated heater is removably positioned within the internal cavity. The heater can either be recharged and placed back within the cavity, or, simply replaced with another oxygen activated heater. In such a situation, the packaging would be re-sealable after re-insertion of the heater. 
     In yet another preferred embodiment of the present invention, a portion of the outer layer that is attached/associated with the object to be heated comprises an interfacial surface that enhances heat transfer and heat efficiency from the heater package to the object to be heated. In this preferred embodiment, the interfacial surface is selected from one of the group comprising thermally conductive adhesives, heat seal layers and non-porous high contact surfaces. 
     In a preferred embodiment, the invention further includes an insulation layer associated with the outer layer. The insulation layer allows heat to be maintained within the object to be heated and to insulate a user coming into contact with the heater package from excessive temperatures. 
     In a preferred embodiment of the invention, the insulation layer comprises insulating films. These films may be constructed from polystyrene and polypropylene. Of course, other films are also contemplated. In the preferred embodiment of the invention, the insulting film has a thickness of approximately 20-30 mils. 
     In still another preferred embodiment, the present invention comprises an inwardly reflecting structure associated with the outer layer, wherein the inwardly reflecting layer allows heat to be maintained within the object to be heated and to insulate a user coming into contact with the heater package from excessive temperatures. In this embodiment, the reflective layer is selected from at least one of the group comprising aluminized polypropylene and polyester films. 
     In yet another preferred embodiment of the invention, the heater package further includes a water retention configuration to help control maximum temperature reached and the desired heating profile for a desired application, safety and comfort. In the preferred embodiment of the invention, the water retention configuration substantially contains egress of water at the site of the exothermic reaction associated with the oxygen activated heater. 
     It is to be understood that the aspects and objects of the present invention described above may be combinable and that other advantages and aspects of the present invention will become apparent to those having ordinary skill in the art upon reading the following description of the drawing and the detailed description thereof. 
    
    
     
       BRIEF DESCRIPTION DRAWINGS THE DRAWINGS 
       The present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that the accompanying drawings depict only typical embodiments, and are, therefore, not to be considered to be limiting of the scope of the present disclosure. The embodiments will be described and explained with specificity and detail in reference to the accompanying drawings as provided below. 
         FIG. 1  is a front perspective view of an embodiment of the present invention. 
         FIG. 2  is an exploded view of an embodiment of the present invention. 
         FIG. 3  is a side view of an embodiment of the present invention. 
         FIG. 4  is an exploded front perspective view of an embodiment of the present invention. 
         FIG. 5  is an exploded front perspective view of an embodiment of the present invention. 
         FIG. 6  is a side cutaway view of an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION THE DRAWINGS 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail several embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. 
     Reference throughout this description to features, advantages, objects or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, any discussion of the features and advantages, and similar language, throughout this specification may, but does not necessarily, refer to the same embodiment. 
     Package Form 
     As shown in  FIGS. 1-6 , the invention is directed towards improving the package for the heater  10 , including but not limited to: stand up pouches, sachets, pillow pouches; labels including but not limited to pressure-sensitive, shrink, sleeves, wraparound, glue applied; heat applied via a heat seal layer; integrated in or applied to substrate materials including but not limited to glass, metal or plastic bottles or molded containers, paperboard or molded paper or fiber or fabric cartons or other contained forms; for various consumer uses including but not limited to convenient delivery of the packaged contents at the hotter temperature, heat applied to a desired surface including a part of a person&#39;s body and containers  70  used to keep food or beverages warm via take-out. 
     Packaging Features 
     In another aspect of the present invention, the invention is directed towards improving reactant control, thermal control, heat initiation and graphics of the package for the heater. 
     As shown in  FIG. 5 , the invention comprises barrier layers, wherein the package or label will comprise an inner and outer layer  12 ,  16 , respectively, designed to permit controlled ingress of the reactant, oxygen, to initiate and promote the heat generating reaction. Target barrier structure properties will be chosen to achieve goal heat generation rates depending on application, including but not limited to heat up time ranges including 5 to 10 minutes and delta heat ranges including but not limited to from ambient to 140 deg. F.; and, shelf life for the device including but not limited to 3-6 months under desired storage conditions for perishable items and 1 to 3 years under desirable storage conditions for non-perishable items. 
     To achieve this control, oxygen transmission rate ranges for the inner and outer layer films can include (but not be limited to) ranges including 0.5 to 18 cc/100 in 2 /day and moisture vapor transmission rate ranges for the inner and outer layers will include and not be limited to &lt;0.2 g/100 in 2 /day. In addition, it is preferred that these materials have a minimum H 2  permeability, including but not limited to 4 cc/100 in 2 /day. 
     To achieve this, barrier structures can include (but are not limited to) metallized and coextruded barrier structures including but not limited to a metalized layer or layers; and/or a coextruded or coated poly (ethylene vinyl alcohol (EVOH), poly vinyl alcohol (PVOH), polyglycolic acid (PGA), or similar barrier polymer layer or layers on cast, uniaxial or biaxially oriented polypropylene, polyester, polycarbonate, cellulose, other biopolymers or nylon. Furthermore, in the case of metallized barrier structures, it is possible to leave imperfections, skips, or non-metallized sections of the barrier material in order to achieve the desired barrier properties. 
     These barrier layers may or may not include a laminated clear or opaque layer for added protection, graphics or other function. The range of materials for these layers can include (but are not limited to) clear or opaque, cast or oriented polypropylene, polyester, nylon, cellulose, biopolymer films with coated, extruded or coextruded heat sealable or otherwise (e.g. RF, UV bonding) adherable layers. The range of opacity technologies may include but not be limited to white pigments such as TiO 2 , BaSO 4 , CaCO 3  or voids as characterized for example in white voided polypropylene films or foamed films such as those commercially available from Exxon Mobil and other suppliers. 
     With respect to reactant control, the invention also relates to diffusing layers, wherein the package or label will comprise a diffusing layer when needed to achieve the above mentioned desired heat up rates to the above mentioned desired temperatures. The layer will be chosen to enable uniform distribution of the reactant oxygen. 
     This can be achieved by including materials that allow the ingress of the reactant, oxygen, but retard the loss of moisture vapor, liquid water, and larger molecules such as electrolytes. Materials should be chosen with ranges of oxygen permeability to include but not be limited to 100 to 1000 cubic feet min/ft 2  at 125 Pascals in thickness ranges to include but not be limited to 5 to 30 mils and suitable pore size to limit transmission of liquids and larger molecules. 
     Materials will include (but are not limited to) non-woven or woven synthetic and natural fiber composites such as cloth or felt and melt spun and/or melt bonded or melt woven polymeric structures including but not limited to polyethylene, polypropylene, polyester and to monolithic film structures designed for inherent gaseous permability and liquid vapor retention including but not limited to polyether polyesters such as DuPont&#39;s Hytrel® films, and open cell and/or partially open cell foam structures 
     With respect to thermal control, the invention relates to thermal transfer, wherein adhesives, heat seal layers and the surface used to apply the device to the substrate or article being heated will be designed to maximize heat transfer and heat efficiency. This can include (but is not limited to) thermally conductive adhesives and heat seal layers and non-porous high contact surfaces. The ranges for heat conductivity can include those characterized in heat conductive films, greases and coatings used with heat generating power transistors in consumer electronics applications. 
     With respect to thermal control, the invention also relates to optimization of thermal transfer, wherein the heater structure is positioned to take advantage of convection within the product being heated. In particular, when heating liquids the heater is positioned such that heat transfer occurs in a way that promotes convective movement within the liquid being heated. 
     With respect to thermal control, the invention also relates to insulation, wherein outer structures that come into contact with the consumer will be designed to maximize insulation of the heat to maximize heat input to the contents of the article being heated and minimize heat loss and unsafe or uncomfortable heat to the user. (See, for example,  FIG. 5 ). 
     This can include, for example, improved insulating and/or inwardly reflective structures for the outer layer of the package or label. Ranges for the insulating properties can be those characterized by insulating films such as 20-30 mil thick foamed polystyrene and polypropylene films. Reflective property ranges can include those characterized by aluminized 18 to 23 micron polypropylene and polyester films. 
     With respect to thermal control, the invention further relates to heating profile control, wherein the construction will also include but not be limited to a specifically engineered water retention and/or loss to limit the maximum temperature reached and to achieve the desired heating profile for the desired application, safety and comfort. 
     The range of technologies to achieve this includes technologies that trap or prolong the existence of moisture vapor at the site of the exothermic reaction. 
     With respect to heat initiation, the invention relates to a package with a hinged flap  80  ( FIG. 6 ), wherein the package or structure will be designed to easily enable the onset of heat via removal of the outer barrier layer to allow the entry of the reactant, oxygen. 
     This can be, for example, a scored layer on three sides with the remaining side serving as a hinge. Opening the flap at the scored line will expose the diffusing layer below to oxygen in the air initiating the heat generation. Scoring can include laser scoring and die cutting. To initiate the tear, the construction can also include an easily grasped tab. The ranges for scoring depths will be characterized as those enabling retention of integrity and barrier through manufacture, application, distribution and handling of the package or label while still permitting a convenient pull force to peel it away similar to the force ranges in peelable lidding. 
     With respect to heat initiation, the invention further relates to a package with a re-sealable flap, wherein the construction may also include but not be limited to the ability to reseal via adherable coatings or surfaces on the inner and outer surfaces of the outer film and scoring designed so that the peeled away flap will overlap the underlying cut out to enable resealing. 
     The material for the adherable layers on the films can include coated, extruded, coextruded, laminated and extrusion laminated adherable materials currently used in resealable packaging offerings. 
     With respect to heat initiation, the invention also relates to a package with a removable flap, wherein the construction may also include and not be limited to a complete peripheral or circumferential scoring for complete removal of the flap that may include but not be limited to printed information that may be a recipe or other instructions or may be a coupon for a future purchase. The construction may also include but not be limited to multiple removable areas in various geometric shapes and sizes to enable the optimum ingress of the reactant oxygen for the desired heat rate for the desired application. 
     With respect to package graphics, the invention relates to a package with printed graphics, wherein the outer layer of the package or label will include but not be limited to a film that can be directly printed or reverse printed and laminated to the aforementioned barrier films of the outer layer. The composition of this film may include: clear or opaque cast, uniaxial or biaxially oriented polypropylene, polyester, polyethylene, cellulose, other biopolymers and nylon. 
     Lamination may be effected, for example, via pressure sensitive adhesives, hot melt glues, as well as thermal lamination via thermal adhesive layers applied via coating, extrusion and co-extrusion. 
     The range of materials for these adhesive layers may include but not be limited to existing laminated film constructions used in packaging as for example linear low density polyethylene, ethylene copolymers, heat sealable polypropylene, and silicon polymers such as poly siloxanes and poly silicones. Printing methods may include screen, gravure, rotogravure, offset, flexographic, and ink jet. Printing methods may also include direct digital printing, indirect methods via separation films and printing plates, as well as direct digitally produced printing plates via for example laser ablation. 
     With respect to package graphics, the invention relates to a package with certain special effect graphics  25 , wherein the package or label may also include and not be limited to thermal sensing technology to show the onset of heat for the device. 
     The range of these technologies may include thermochromic inks that change color with heat, printed electronics that sense temperature and emit a signal to a remote handheld device such as a mobile phone that could be a digital temperature readout or other visible or audible signal; printed electronics that emit an audible signal at the package or as mentioned above at a mobile hand held device, printed electronics that emit light at the package or label characterized by current light emitting diodes whether organic or inorganic; and plastics used as dispensing spouts or caps or lids, that are thermochromic such that they change color when a desired temperature is reached. 
     The package or label may also include such special effects to alert the user to desired instructions, coupons or other information via 1D or 2D codes and optical decoding via a camera on a mobile handheld device as characterized in 2D codes and 2D code readers in smart phones or printed electronics and near field communication systems or RFID systems via wireless RF communication from the package or label to a remote handheld device such as a mobile phone. The range of these technologies may include those currently installed on Nokia phones equipped with near field communication. 
     The package or label construction may also include the heat generating layer integrated into the package form. These concepts may include but not be limited to: a corrugated layer  32  ( FIG. 3 ) and/or printed heating material. 
     With respect to the corrugated layer, the heating material (as described under heating material) may be applied to a corrugated layer that also serves as the form for the package or label. The corrugated inner material may include the oxygen transport and liquid and electrolyte retention properties discussed above in relation to the diffusing layer. This construction may include laminated outer layers in the corrugate construction to provide graphics and a peelable window as described above under heat initiation. This construction may also include an inner layer as described above under barrier layers or it may be directly affixed to the article or container being heated. 
     With respect to the printed heating material, the heating material may be applied directly to the package or label via a printed pattern that provides the desired heat up rate and control for the desired application. This may include a separate or printed layer to protect and initiate the heating. Printing methods may include those mentioned previously under graphics. 
     In addition the package or label construction will be designed for sustainable end of life including but not limited to recycling, reuse, compostability, or conversion to energy via choice of materials and design for disassembly. 
     Furthermore, the present invention also contemplates the use of a heater cartridge ( FIG. 6 ) that would be removed from a container, activated and then replaced in the container to provide heating for a liquid containing pouch. Further, a self-contained cartridge heater could be attached to the inside of a box to provide heat to an object within the box. This could include an easy twist in, twist out for easy removal or other easy removal/replacement for activation followed by easy replacement for heating. 
     For the above examples of suitable materials, technologies, or properties, are merely illustrative and are not intended to be limiting to only those materials, technologies or properties listed above. 
     It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.