Shrink film containers for self-heating components

Abstract

A self-heating assembly includes a product tray and a heater tray. The product tray holds a product to be heated. The heater tray is located outside the product tray and configured relative to the product tray to define a reaction space between the heater tray and the product tray. A fragile container made of shrink film material is located inside the reaction space. The fragile container contains a first reactant, which is a liquid. A second reactant is located outside the fragile container. The first and second reactants are configured to undergo an exothermic reaction upon contact with each other.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 992,290, filed March 20, 2020, entitled “Shrink Film Container for Self-Heating Assembly”. The disclosure of the earlier application is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to self-heating assemblies, and more specifically to shrink film containers for self-heating assemblies. Summary of the Invention

[0004] In one aspect, the self-heating assembly includes a product tray and a heater tray. The product tray is used to hold the product to be heated. The heater tray is located outside the product tray and configured relative to the product tray to define a reaction space between the heater tray and the product tray. A fragile container made of shrink film material is located inside the reaction space. The fragile container contains a first reactant, which is a liquid. A second reactant is located outside the fragile container. The first and second reactants are configured to undergo an exothermic reaction upon contact with each other.

[0005] In another aspect, methods for heating a product include providing such a self-heating assembly (with a shrink film material that contains liquid chemical reactants participating in an exothermic reaction) and manipulating a device for breaking the fragile container to activate the exothermic reaction.

[0006] In some implementations, one or more of the following advantages exist.

[0007] For example, a self-heating assembly can be provided that generates heat rapidly, and in fact utilizes most (if not all) of the chemical reactants contained within the self-heating assembly to generate heat without waste. As a result, the self-heating assembly is able to generate a large amount of heat in a highly efficient manner. One or more confirmatory components described herein that contribute to these advantages are relatively simple in design, relatively easy to manufacture, and reliable.

[0008] Other features and advantages will become apparent from the description, drawings, and claims. Attached Figure Description

[0009] Figures 1 to 3 An exemplary embodiment of a self-heating assembly is shown, in which two reactants (one being a liquid (and contained in a shrink film material) and the other a solid) come into contact with each other and react in an exothermic manner.

[0010] Figure 4 This is an exemplary sealed package (containing) Figures 1 to 3 A schematic cross-sectional view of the solid reactants in the self-heating assembly.

[0011] Figure 5 The images show examples of unshrinked, filled fragile containers (bags) and punctured, substantially empty, shrunken fragile containers (bags).

[0012] Figure 6 A graph showing the moisture loss of a fuel bag made only of PVC (i.e., a fragile container) and a fuel bag of the same size made only of polypropylene (i.e., a fragile container) is presented.

[0013] The same reference numerals refer to the same elements. Detailed Implementation

[0014] This application relates to self-heating components of the following types, wherein two reactants (at least one of the reactants is a liquid and the other of the reactants may be a solid) come into contact with each other and react exothermically to generate heat for heating a product (e.g., food or beverage) contained in the self-heating component.

[0015] The liquid reactants within the heating assembly are contained in a fragile container, made of or including a shrink film, before activation. The shrink film contracts upon exposure to heat. In a typical embodiment, to initiate heating, the container is torn, punctured, ruptured, or otherwise damaged to create one or more openings. These openings allow at least some of the liquid reactants to escape from the container. Typically, however, at least some portions of the container (often a considerable portion) remain intact after the damage. Because the container remains intact to some extent, a portion of the liquid reactants is typically still trapped within the container and prevented from reaching the solid reactants. Simultaneously, the liquid reactants that manage to escape from the container through one or more openings come into contact with the solid reactants and begin to react exothermically. This exothermic reaction generates heat, which causes the shrink film of the container to begin to contract. The contraction of the shrink film tends to expel more liquid reactants from the container. This makes more liquid reactants available to react with the solid reactants, and the additional reaction generates more heat to heat the product. As more heat is generated, the heat-shrinkable film shrinks further, thus tending to expel more liquid reactants from the fragile container to further react with the solid reactants.

[0016] In a typical implementation, the amount of liquid reactant that ultimately leaves the fragile container and is therefore available to react with the solid reactant tends to be greater than the amount available to react with the solid reactant if the fragile container is not made of or does not contain a shrink-film material. Furthermore, in a typical implementation, the rate of liquid escape from the fragile container may be increased because the fragile container is made of or includes a shrink-film material. Therefore, in a typical implementation, more heat can be generated in a shorter time by a self-heating assembly, wherein the liquid reactant is contained within the fragile container made of or including a shrink-film material, as described herein.

[0017] Figures 1 to 3 An exemplary embodiment of this type of self-heating component 100 is shown, in which two reactants (one liquid and the other solid) come into contact with each other and react in an exothermic manner.

[0018] The self-heating assembly 100 shown is in some respects similar to the self-heating assembly described in a prior art patent filed on November 19, 2019, entitled "Self-heating Assembly with Distributed Reactants," filed by the current patent applicant Tempra Technology, Inc., patent number 10,478,015, which is incorporated herein by reference in its entirety. However, in Figures 1 to 3 In the self-heating assembly 100, the liquid reactants are contained in a fragile container 110 made of or at least comprised of a shrink-film material. Other differences may also be referenced herein.

[0019] The self-heating assembly 100 shown has two nested trays: a product tray 102 for holding the product to be heated (e.g., food, beverage, etc.), and a heater tray 106 attached to the product tray 102. The product tray 102 is nested inside the heater tray 106, and a reaction space 108 exists between the product tray and the heater tray. In the illustrated embodiment, the reaction space 108 extends from the bottom of the heater tray 106 to the bottom of the product tray 102, and from the side of the heater tray 106 to the side of the product tray 102. In a typical embodiment, the product tray is filled with the product to be heated (e.g., food, beverage, etc.) and then sealed (e.g., secured to and / or bonded to the upper peripheral surface of the self-heating assembly 100 with a suitable lid, foil, etc.).

[0020] The fragile container 110 is located inside the reaction space 108 and surrounds and contains the liquid reactants. In the illustrated embodiment, the fragile container 110 is located below the product tray 102. In a typical embodiment, the fragile container 110 should have a certain degree of resilience. Furthermore, the fragile container 110 should be durable enough to withstand the sometimes rough handling that the self-heating assembly 100 may experience, for example, during transportation and handling.

[0021] In the illustrated embodiment, a sealed package 101 containing the solid reactants is also located below the product tray 102, inside the reaction space 108. Although the package is sealed, in a typical embodiment, the upper surface of the sealed package 101 is liquid-permeable, such that when liquid reactants are released from the fragile container and flow downwards to the upper surface of the sealed container, the liquid reactants pass through the upper surface to reach and react with the solid reactants contained in the package.

[0022] The cutting element 115 extends diametrically across a portion of the reaction space 108 between the fragile container 110 located above the cutting element 115 and the sealed package 101 located below the cutting element 115. In the illustrated embodiment, the cutting element 115 has an elongated shaft with a plurality of cutting blades 157 extending radially outward from the shaft, the blades being generally parallel to each other and perpendicular to the axis "A" of the shaft. The cutting element 115 is supported at opposite ends by support surfaces or bearings that allow the cutting element to rotate about the axis "A" of the shaft in the direction indicated by arrow "B".

[0023] Before initiating the exothermic reaction, the cutting element 115 is configured such that its cutting blade 157 does not point at or pierce the fragile container 110, thus eliminating the risk of cutting or breaking the fragile container 110 before movement. Figure 2 and Figure 3 An example of this configuration is shown, in which the cutting blade 157 extends horizontally outward from an elongated axis between the upper fragile container 110 and the lower sealed package 101.

[0024] Knob 117 is located at one end of the cutting element 115 and exposed on the outer surface of the self-heating assembly 100. When the user turns knob 117, the cutting blade 157 rotates about axis "A," causing the cutting blade 157 to rotate into the fragile container 110 and cut, puncture, break, or otherwise damage the fragile container 110 to create one or more openings in the fragile container 110 through which at least some of the liquid reactants from the fragile container 110 can escape. The extent of the openings thus created can, for example, depend on the relative geometry of the cutting blade 157 and the fragile container 110, and the degree to which the user turns knob 117. On the one hand, if the user turns the knob only slightly, then the one or more openings may be relatively small. On the other hand, if the user turns the knob a lot, then the one or more openings may be relatively large. In either case, in most cases, the one or more openings may not be large enough to ensure that all liquid reactants can be immediately released from the fragile container 110 through the openings. Conversely, in a typical implementation, a portion of the liquid reactants (potentially a considerable amount of liquid reactants) will not be immediately released from the fragile container 110 through one or more openings, but will remain (essentially trapped) within the fragile container 110, unable to come into contact with (and react with) the solid reactants.

[0025] As described above, the sealed package 101 containing the solid reactants is located below the fragile container 110 within the reaction space 108. Furthermore, the sealed package 101 has an upper layer permeable to the liquid reactants. Because the fragile container 110 is located above the sealed package 101, and because the sealed package 101 has an upper layer permeable to the liquid reactants, any liquid reactants released from the fragile container 110 generally flow downwards under gravity and through the liquid-permeable upper layer of the sealed package into the sealed package 101. The liquid reactants come into contact with the solid reactants within the sealed package 101, thereby initiating an exothermic reaction.

[0026] Heat from the exothermic reaction flows upward through the reaction space 108 to the bottom and sides of the product tray 102 and flows through the bottom and sides of the product tray to heat the product contained therein. Heat also reaches the fragile container 110, which is made of or includes a shrink film, causing the fragile container 110 to begin to shrink. When the heat generated by the vigorous reaction causes the torn fragile container 110 to begin to shrink, the shrinkage tends to expel more of the remaining liquid reactants from the fragile container 110 through one or more openings in the fragile container 110.

[0027] As shrinkage continues, the more the fragile container shrinks, the more of the remaining liquid reactants are squeezed out. The more liquid reactants escape, the more heat is generated in the self-heating assembly 100. The more heat is generated in the self-heating assembly 100, the more the fragile container shrinks. Therefore, in a typical embodiment, the fact that the fragile container is made of or includes a shrink film material helps ensure that a larger percentage of the liquid reactants in the heating assembly reacts more quickly with the solid reactants in the self-heating assembly 100. Thus, in a typical embodiment, the self-heating assembly 100 can generate a large amount of heat very efficiently and very quickly.

[0028] The reaction space 108 accommodates a continuous exothermic reaction, from which heat continues to pass through the product tray 102 to heat the product contained therein. In a typical embodiment, after the heating process is initiated (e.g., by turning a knob to break the fragile container 110), a period of time (e.g., about one minute) passes, and then the user peels off the lid of the self-heating assembly 100 to access and consume (or otherwise use) the heated product within the product tray 102. In some embodiments, a heating time of several minutes may be required to adequately heat the product; however, the time can vary depending on the design of the self-heating assembly and the heat capacity and viscosity of the food or product to be heated within it.

[0029] The fragile container 110 can be made of any one or a combination of various materials. In a typical embodiment, at least one such material is a shrink film material. Several examples of suitable shrink film materials include polyethylene (PE), polyvinyl chloride (PVC), polyolefin (POF), polyethylene terephthalate (PET), polylactic acid (PLA), and combinations thereof. In this embodiment, the shrink film material typically forms a closed bag portion that surrounds and contains the liquid reactants.

[0030] Some shrink film materials have a higher moisture vapor transmission rate (MVTR) than others. MVTR is a measure of water vapor permeability; it can represent the permeability of a moisture barrier. It is generally undesirable for liquid reactants to escape from the fragile container 110 (e.g., by penetrating the fragile container) unless and until the user intentionally activates the self-heating assembly 100 (e.g., by turning a knob to break the fragile container 110). Therefore, in some embodiments, particularly those where the shrink film material may have a high MVTR, the fragile container 110 includes a moisture barrier material in addition to the shrink film material. In some embodiments, it may be desirable to select a moisture barrier material such that the overall MVTR of the fragile container meets the requirement of less than 20% moisture loss per year. Several examples of liquid barrier materials that may be suitable for various embodiments include ethylene-vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), and Saran. TM (Polyethylene coating material) or polypropylene. In this embodiment, the moisture barrier material helps prevent moisture from escaping from the fragile container 110 until and unless the fragile container is intentionally broken (e.g., by the user turning knob 117).

[0031] In embodiments including a moisture barrier material, the moisture barrier material can form a closed bag portion that surrounds and contains the liquid reactant. The moisture barrier bag portion can be located inside the shrink material bag portion. Furthermore, the space between the shrink material bag portion and the moisture barrier bag portion is typically emptied, such that the shrink material bag portion is in direct physical contact with the entire outer surface of the moisture barrier bag portion. Typically, there is no empty space between the two bag portions. Therefore, when the knob is rotated to break the fragile container 110, the cutting blade 157 is screwed into both the shrink material bag portion and the moisture barrier bag portion and substantially simultaneously cuts, punctures, breaks, or otherwise destroys both the shrink material bag portion and the moisture barrier bag portion.

[0032] There are various ways to manufacture fragile containers 110, including shrink film layers and moisture barrier layers.

[0033] In one example, with the shrink film layer located inside the vapor barrier layer, the liquid reactant is poured into an open shrink film bag. The shrink film is then sealed using a vacuum sealer. The sealed shrink film bag containing the liquid reactant is then placed inside an open moisture barrier bag. The moisture barrier bag is then sealed using a vacuum sealer to enclose and contain the sealed shrink film bag, thus minimizing air between the two bags.

[0034] In another example, with the shrink film layer located outside the vapor barrier layer, the liquid reactant is poured into the open vapor barrier bag section. The vapor barrier bag section is then sealed using a vacuum sealer. The vapor barrier bag section containing the liquid reactant is then placed inside the open shrink film layer bag section. The shrink film layer bag section is then sealed using a vacuum sealer to enclose and contain the sealed vapor barrier bag section, thus virtually eliminating air between the two bag sections.

[0035] Alternatively, the shrink film material and the moisture barrier material can be co-formed in a single sheet (e.g., by co-extrusion or lamination) and used to form a fragile layer with the shrink film material inside or outside the vapor barrier layer. In some such embodiments, the sheet can be used to form an open bag portion, into which liquid reactants are then poured and the bag portion is sealed with a vacuum sealer.

[0036] Other methods for forming, filling and / or sealing the fragile container 110 are also possible.

[0037] In a typical implementation, it is desirable to maximize the shrinkage of the fragile container 110 during heater operation, but to avoid shrinkage of the fragile container at any temperatures that the self-heating assembly 100 may be exposed to during anticipated transport, handling, storage, etc. Some shrink film materials (e.g., polyvinyl chloride (PVC)) shrink considerably, both longitudinally and laterally. These types of shrink film materials can help ensure that a significant amount of liquid reactants in the fragile container 110 ultimately drains from the fragile container 110 during heating. Furthermore, it may also be desirable that some shrinkage materials (e.g., PVC) begin to show significant shrinkage at very low temperatures (e.g., approximately 150 degrees Fahrenheit).

[0038] Figure 5 The images show examples of an unshrinked, filled fragile container (bag) and an example of a punctured, substantially empty, and shrunken fragile container (bag). The bag was initially approximately 3 inches by 3 inches and contained 44 cubic centimeters (cc) of liquid. After heating, the bag was measured to be approximately 1.12 inches by 2 inches, indicating a reduction in area to approximately 0.23 of the bag's original size. The shrinkage in the longitudinal direction was significantly greater than the shrinkage in the transverse direction. After shrinkage and significant wrinkling, approximately 2 cc of liquid remained in the bag, or 5% of the original liquid. The puncture that initiated the reaction was not visible due to the shrinkage and wrinkling, but it was a simple puncture without tearing.

[0039] Self-heating containers / food heating packages using fragile containers (bags) typically must have a shelf life of several months before the product can be used for commercial purposes. Under some storage conditions, components of the heating system may be subjected to temperatures far above normal room temperature. As discussed herein, vapor can permeate the plastic film, and the permeability generally increases with increasing temperature.

[0040] The liquid reactant used in systems designed to use these bags is approximately 70% water (e.g., between approximately 60% and 80%), and the water content of the liquid reactant is one of the main moderating factors for the heating reaction. Generally, the lower the water content, the faster the reaction. In heating non-liquid foods, the rate of heat generation by the heater should be very close to the rate at which the food can absorb heat without stirring. Tests have shown that a water loss well over 10% wastes a portion of the usable food heating energy through steam emission, which is unacceptable. For the fuel bags in this particular system, an acceptable net water loss is approximately 4 grams.

[0041] Figure 6 A graph shows the moisture loss of fuel bags (i.e., fragile containers) made solely of PVC and fuel bags (i.e., fragile containers) of the same size made solely of polypropylene. Based on the data shown in the graph, the room temperature lifespan of fuel (i.e., liquid reactants) in the two bags (i.e., fragile containers) is approximately 114 days and approximately 571 days, respectively. The situation worsens with increasing temperatures. At 120 degrees Fahrenheit, the PVC bag loses approximately 0.31 grams of moisture per day, resulting in a lifespan of only thirteen days. Of course, the performance of the polypropylene bag also deteriorates with increasing temperatures. The polypropylene bag loses 0.069 grams of moisture per day, resulting in a lifespan of 58 days. It may not be necessary to point out that there is no habitable place on Earth with a temperature of 120 degrees Celsius for 24 hours a day. The reason for choosing this elevated temperature is that vapor diffusivity is highly non-linear with temperature.

[0042] Figure 6 The data shown supports the proposal that one solution to the limited shelf life problem of PVC-only shrink bags (a fragile material) is to line the shrink bag with polypropylene. As long as the inner bag containing the liquid reactants is not too thick, the serrations used to initiate the heating process can easily puncture both bags. This solution has proven satisfactory. Figure 5 The unshrinked sample bag shown is actually a double-layered bag. The inner bag is not visible.

[0043] In a typical implementation of the self-heating assembly 100, and as... Figures 1 to 3As shown, the dimensions of the sealed package 101 are determined such that the sealed package completely fills the bottom of the reaction space 108, leaving almost no empty space around the perimeter of the reaction space. This helps ensure that all liquid reactants flowing out of the ruptured and subsequently shrinking fragile container 110 ultimately flow into the sealed package 101 to react with the solid reactants contained within the sealed package.

[0044] Figure 4 It shows Figures 1 to 3 A cross-sectional view of an exemplary embodiment of the sealed package 101 (containing solid reactants).

[0045] The sealed package 101 shown has a tray-shaped outer container 460, a lower support structure 462 (e.g., a tray of open-cell foam or the like) located within the outer container 460, a layer of non-particulate solid reactant 464 (e.g., a tray of solid reactant) located above the lower support structure 462 and within the outer container 460, an upper structure 466 (e.g., another tray of open-cell foam or the like) located above the solid reactant 464 and within the outer container 460, and an upper layer 468 (e.g., paper or the like) that is permeable to liquids (e.g., permeable to liquid reactants) and extends over the upper structure 466 across another open top of the outer container 460.

[0046] In the illustrated embodiment, the outer container 460 forms a tray having a flat bottom, raised edges, and an outwardly extending flange. The upper layer 468 extends across an opening at the top of the tray to seal the contents of the tray. More specifically, in the illustrated embodiment, the outwardly extending flange provides a surface to which the upper layer 468 of the sealed package 101 is adhered or secured.

[0047] Any of a variety of adhesive materials can be used to bond the upper layer 468 of the sealed package 101 to the outwardly extending flange of the outer container 460. In a typical embodiment, the adhesive material is configured to maintain tack for a sufficient duration to allow the cover sheet to be properly positioned and pressed down. In various embodiments, the adhesive material is a super glue, hot melt adhesive, two-component epoxy resin, Amazing Goop... ® Adhesives, household cement cured into some kind of elastic adhesive, or any other suitable adhesive. Furthermore, in a typical implementation, the adhesive material is impermeable to boiling water.

[0048] Furthermore, the adhesive material is typically one that remains intact and maintains contact between the upper layer 468 and the outwardly extending flange throughout the entire lifespan of the sealed package 101 and the self-heating assembly 100. Therefore, in a typical embodiment, the adhesive material should be one that can withstand (and maintain adhesion) exposure to liquid reactants and temperatures associated with exothermic reactions (e.g., boiling water, approximately 100 degrees Celsius).

[0049] Any of a variety of other techniques can be used to secure the upper layer 468 of the sealed package 101 in place across another open top of the outer container 460. For example, in some embodiments, the outer periphery of the upper layer 468 may be rolled onto an outwardly extending flange of the outer container 460.

[0050] The outer container 460 of the sealed package 101 can be made of any of a variety of solid materials. Typically, the outer container 460 is impermeable to liquids and capable of withstanding the temperatures associated with the exothermic reaction in the self-heating assembly 100. Furthermore, the outer container 460 is typically made of a solid material that can be shaped into a desired configuration (e.g., Figure 4 (As shown in the tray-like shape) and at least partially resists deformation. An example of this material is aluminum. Another example of this material is copper, which is more expensive than aluminum but may be only half the thickness of aluminum.

[0051] The outer container 460 is made of a material (e.g., aluminum) with a thickness. This thickness can vary. However, in some cases, it may be desirable for the aluminum outer container to have a wall thickness of at least 0.005 inches. This minimum thickness helps ensure that even under fairly extreme off-design conditions, localized heating will not damage the typically plastic heater tray 106. The thermal conductivity associated with aluminum having at least a minimum thickness helps prevent such damage. In some embodiments, the aluminum tray may have a wall thickness between 3 mm and 4 mm.

[0052] Of course, the height of the outer container 460 (i.e., the distance between the bottom and the flange) can vary. In various embodiments, the height of the outer container 460 can be between about 1 / 4 inch and 1 inch.

[0053] The lower support structure 462 is located at the bottom of the outer container 460. In a typical embodiment, the lower support structure 462 is disc-shaped and made of open-cell foam or another honeycomb or porous material through which liquid (e.g., liquid reactants) can flow or pass. In the illustrated embodiment, the lower support structure 462 is sized to cover the entire inner bottom surface of the outer container 460. Furthermore, in the illustrated embodiment, the side edges of the lower support structure 462 contact the inner sidewall of the outer container 460 around its entire perimeter.

[0054] In some embodiments, some solid reactants (in particulate form) may be dispersed on the lower support structure 462, and for example, supported on the top of the lower support structure 462 and / or within the openings or pores of the lower support structure 462. In these embodiments, the solid particulate reactants may be substantially uniformly dispersed on the lower support structure 462.

[0055] The lower support structure 462 is typically configured to facilitate the flow of liquids (e.g., liquid reactants) through it. This allows any liquid reactants reaching, for example, the outer periphery of the lower support structure 462 to flow through it, and to any particulate solid reactants that may be dispersed within and / or on top of it, as well as to the bottom surface of the layer of solid reactants 464 directly above the lower support structure 462. In a typical embodiment, this helps ensure that the exothermic reaction occurs rapidly and increases the likelihood that more particulate reactants will actually react.

[0056] In a typical implementation, the lower support structure 462 has sufficient structural integrity to physically support any component located on top of the lower support structure 462 without excessive compression, which could impair the lower support structure's ability to carry liquid reactants to or above particulate solid reactants within or above the lower support structure 462, and to the bottom surface of the layer of solid reactants 464 directly above the lower support structure. In the illustrated implementation, for example, the lower support structure 462 is robust enough to physically support any particulate solid reactants above or within the lower support structure 462, the layer of non-particulate solid reactants 464 above the lower support structure 462, and the upper structure 466 above the layer of non-particulate solid reactants 464. Typically, the lower support structure 462 achieves this with no more than very small (if any) significant compression (e.g., less than about 10% of the thickness of the lower support structure).

[0057] In the illustrated embodiment, the height of the lower support structure 462 (e.g., from the lower surface of the lower support structure that contacts the bottom of the outer container 460 to the upper surface of the lower support structure opposite to and above its lower surface) is approximately one-third of the height of the outer container 460. Of course, this can vary considerably, and the lower support structure 462 can have any height from about 1 / 16 inch (or less) to 1 / 2 inch (or more). In one exemplary embodiment, a tray of approximately 1 / 8 inch thick open-cell plastic foam can be placed at the bottom of an aluminum tray before the granular material is poured into the tray. This, of course, provides a fuel flow path to the underside of the blocky cast granules during operation of the self-heating assembly 100.

[0058] The size of individual particles of the particulate solid reactant, which can be dispersed on and throughout the lower support structure 462, can also vary. Some particle sizes can be determined such that these particles are located at the top of the open-cell foam material of the lower support structure 462. Some particle sizes can be determined to fit within the openings or pores of the lower support structure 462. In some embodiments, the size of individual particles can vary such that some particles are located at the top of the lower support structure 462, and some particles are located within the openings or pores of the lower support structure 462.

[0059] In some embodiments, the particles are very small compared to the openings or pores of the lower support structure 462, which may have a nominal pore number (e.g., between approximately 25 and 45 pores per inch (e.g., 30 PPI)), allowing particles to fall into the lower support structure 462, and at least some particles to reach the bottom (or near the bottom) of the lower support structure 462 through the openings or pores. It may be desirable to have particles at or near the bottom of the lower support structure 462 because these particles will begin to react once the liquid reactants reach them (e.g., by flowing downwards to the bottom of the chamber). The resulting reaction leads to boiling, which helps to wet the bottom surface of the reactant particles located higher in the lower support structure 462, as well as the layer of non-particulate solid reactants 464.

[0060] In the illustrated embodiment, a layer of non-particulate solid reactant 464 is located above and in direct physical contact with the lower support structure 462. This layer of solid reactant 464 is in the form of a rigid disk with a flat top surface, a flat bottom surface, and cylindrical side surfaces. The layer of non-particulate solid reactant 464 typically has a disc-like consistency and therefore tends to maintain its disk-like configuration under normal handling conditions. Furthermore, in a typical embodiment, the solid binder particles are sufficiently hard and robust for handling, but are easily broken and brittle. Additionally, in a typical embodiment, the layer of non-particulate solid reactant 464 typically maintains its disk-like configuration unless and until the layer of non-particulate solid reactant is exposed to a liquid reactant with which it undergoes an exothermic reaction. This reaction begins to damage the disk-like configuration of the layer of non-particulate solid reactant 464. As the reaction continues, the layer of non-particulate solid reactant 464 gradually dissolves until only a small amount of solid reactant remains or no solid reactant remains.

[0061] In some embodiments, the solid reactant (whether particulate or non-particulate) is the oxidant (e.g., potassium permanganate, which may be coated with sodium silicate), and the liquid reactant is the reducing agent (e.g., aqueous glycol fuel). Of course, other types of reactants can be used instead. In this respect, many oxidants are capable of producing suitable energy when reacting with the corresponding fuel. Typical oxidants include alkali metal salts containing oxides of manganese and chromium. These oxidants include compounds such as potassium permanganate and potassium chromate. Other suitable oxidants are pyridinium dichromate, ruthenium tetroxide and chromic acid, and many other oxidants. Preferably, the oxidant comprises alkali metal salts of permanganate. The corresponding fuels suitable for use in exothermic chemical reactions are typically organic compounds. Particularly suitable organic compounds are alcohols. Alcohols are readily oxidized by the aforementioned oxidants to carbonyl-containing compounds. Alcohols can be primary alcohols, preferably polyols containing at least two hydroxyl groups. Such polyols are also readily oxidized to aldehydes and carboxylic acids. This oxidation of polyols and the simultaneous reduction of the oxidant usually involves the release of a large amount of heat energy. A preferred fuel is glycerol.

[0062] In a typical implementation, the layer of non-particulate solid reactant 464 contacts and / or is pressed downward onto the upper surface of the lower support structure 462, which helps to maintain the particulate solid reactant typically substantially uniformly distributed on top of the lower support structure 462, at least until the layer of non-particulate solid reactant 464 begins to dissolve.

[0063] Various methods exist for forming a layer of non-particulate solid reactant 464. In one such exemplary method, the solid reactant (e.g., potassium permanganate coated with sodium silicate) can be supplied as a powder or in granular form to a cylindrical container and then exposed to humidity (e.g., in a humid environment or by using a humidifier, i.e., a collection of components that generate humidity). In an exemplary embodiment, the humidity causes the sodium silicate to absorb moisture from the humid environment and bind the powdered or granular solid reactant into a spherical or disc-shaped configuration. The disc-shaped solid reactant is then typically removed from the humidity and dried. In some embodiments, drying can be accelerated by exposing the disc-shaped solid reactant to a heated environment (e.g., in an oven) for a period of time. The heated environment can be a relatively low temperature (e.g., 120°F), and the period of time can be, for example, between 1 hour and 4 hours. However, higher temperatures and shorter times can certainly be used to dry the humidified discs.

[0064] The upper structure 466 in the outer container 460 is disc-shaped and made of open-cell foam or another honeycomb or porous material through which liquids (e.g., liquid reactants) can flow or pass. In some embodiments, the upper structure 466 is made of the same material as the lower support structure 462. However, this is not always the case. For example, in some embodiments, the openings or pores in the upper structure 466 may be larger than those in the lower support structure 462. In some embodiments, the openings or pores in the upper structure 466 may be smaller than those in the lower support structure 462.

[0065] In the illustrated embodiment, the upper layer 468 extends across and covers the open top of the outer container 460. More specifically, the outer periphery of the bottom surface of the upper layer 468 is secured to the upper surface of the outwardly extending flange portion of the outer container 460. In some embodiments, the upper layer may be secured using a hot melt adhesive or any other type of adhesive or securing technique that can keep the upper layer 468 in contact with and sealed relative to the outer container 460 throughout the entire service life of the self-heating assembly 100. When the upper layer 468 is thus bonded to the outwardly extending flange portion of the outer container 460, the upper layer 468 and the outer container 460 together seal the inner compartment of the self-heating assembly 100, thereby preventing any loose powder or the like from escaping from the self-heating assembly 100.

[0066] In a typical implementation, the upper layer 468 is paper. However, in various implementations, the upper layer 468 can be another material. This other material should be permeable to liquids and able to withstand the operating conditions associated with the self-heating assembly 100.

[0067] Sealed packages 101 can be assembled in various ways.

[0068] One implementation of the assembly process includes providing components for the assembly process, including an outer container or a material shaped into an outer container (e.g., aluminum), one or more sheets of open-cell foam or another honeycomb or porous material forming or used as a lower support structure and an upper structure, solid reactants (typically provided in granular form), paper forming the upper layer (or some other liquid-permeable and application-suitable material), and adhesive materials.

[0069] If the provided sheet of aluminum or other material is not in the shape of a tray, the sheet of aluminum or other material is formed to form a tray, typically a tray with an outwardly extending upper flange, such as... Figure 1 As shown.

[0070] Next, if necessary, cut open-cell foam or other honeycomb or porous materials to fit snugly to the bottom of the outer container to serve as a lower support structure. The lower support structure is then positioned at the bottom of the outer container.

[0071] Next, the particulate reactants are poured into the outer container, placing them on top of the lower support structure, typically filling at least a portion of the openings in the lower support structure.

[0072] Next, a non-particulate disk of the solid reactant is formed. This non-particulate disk of the solid reactant can be formed in various different ways. For example, the non-particulate disk of the solid reactant can be formed outside the outer container, falling onto the top of the particulate material already poured onto the lower support structure. Alternatively, the non-particulate disk of the solid reactant can be formed inside the outer container, on top of the particulate material already poured onto the lower support structure.

[0073] There are various methods for forming non-particulate disks of solid reactants on the exterior of an outer container. For example, solid reactants (e.g., potassium permanganate coated with sodium silicate) can be supplied as powder or granules into a cylindrical container and placed on a support above water inside the container. This exposes the granular material to humidity. The humidity causes the sodium silicate to absorb moisture from the humid environment and bind the powdered or granular solid reactants into a spherical or disk-shaped configuration. The disk-shaped solid reactants are then removed from the humidity, allowing them to dry. In some embodiments, drying can be accelerated by exposing the disk-shaped solid reactants to a heated environment (e.g., in an oven) for a period of time. If this method of forming non-particulate disks of solid reactants is used, disks (in fact, multiple disks) can be prepared prior to the assembly of one or more sealed packages.

[0074] There are various ways to form non-particulate disks of solid reactants inside the outer container on top of granular material that has already been poured onto and into the lower support structure. For example, additional granular material can be poured into the outer container on top of any granular material already poured into the lower support structure. In a typical embodiment, this additional granular material may be sufficient to form a layer with a thickness equal to or at least substantially similar to the thickness of the lower support structure. Next, the outer container containing the granular material inside the lower support structure and the outer container is placed in a humid environment. This exposes the granular material to humidity. The humidity causes the sodium silicate to absorb moisture from the humid environment and bind the powdered or granular solid reactants into a spherical or disk-shaped configuration. This binding can also cause the solid reactants to bind to the inner walls of the lower support structure and the outer container. The outer container is then removed from the humidity, allowing the granular material inside the outer container to dry. In some embodiments, drying can be accelerated by exposing the outer container to a heated environment (e.g., in an oven) for a period of time.

[0075] This adhesion helps ensure that, for example, when the container is tipped over during transport or storage, the non-granular discs do not shift around or move to one side of the reaction chamber. In a typical implementation, foam helps prevent powder displacement.

[0076] Next, if necessary, cut open-cell foam or other honeycomb or porous material into pieces that fit snugly above the disk of solid reactants in the outer container to serve as a superstructure. The superstructure is then positioned inside the outer container, above the disk of non-particulate solid reactants.

[0077] Next, if necessary, the paper (or other liquid-permeable and suitable material for the application) is cut to extend over the open top of the outer container. The material is then typically attached to the outer container using a hot melt adhesive, bonding the outer periphery of the lower surface of the paper to the outwardly extending flange of the outer container. In a typical implementation, the hot melt adhesive is applied to the entire periphery of the paper / flange interface without interruption. Thus, this material serves as the upper layer of the outer container, sealing the aforementioned solid reactants and foam within the sealed packaging.

[0078] Having a pre-assembled sealed package 101 (i.e., a sealed package 101 assembled prior to the manufacture of the self-heating assembly 100, as described above) contributes to the manufacturability of the self-heating assembly 100. In this respect, the sealed package 101 (or multiple sealed packages 101) can be manufactured, and when the self-heating assembly 100 is being manufactured, one of the sealed packages 101 can simply fall into the bottom of the self-heating assembly 100 at an appropriate point in the manufacturing process. This simplifies the handling of solid reactants (particulate solid reactants) during the manufacturing process of the self-heating assembly 100. For example, without the pre-assembled sealed package 101, there is a significant risk that particulate reactants may spill or become airborne, creating a mess and / or eventually entering unwanted parts of the self-heating container. However, with the pre-assembled sealed package, the containment and control of particulate reactants are considerably simplified and improved.

[0079] To activate the heating function in the self-heating assembly, the user manipulates knob 117 to rotate the shaft about axis "A" in the direction indicated by arrow "B". This causes the cutting blade 157 to move into the fragile container 110 and ultimately cut or break the fragile container 110. In the example shown, to manipulate the knob in this way, the user can first lower knob 117 to the active position (e.g., by oscillating the knob about hinge 121) and then rotate the knob about axis "A" in the direction indicated by arrow "B".

[0080] When liquid fuel is released from the fragile container 110, it flows downward toward the bottom of the self-heating assembly 100. Since the sealed package 101 is located at the bottom of the self-heating assembly 100 and fills (or at least substantially fills) the bottom of the self-heating assembly 100, most (if not all) of the liquid fuel released from the broken fragile container 110 passes through the upper layer 468 of the sealed package 101 and enters the sealed package 101.

[0081] Liquid fuel flowing into the sealed package 101 passes through the open honeycomb structure of the upper structure 466 inside the sealed package 101. The open honeycomb structure of the upper structure 466 tends to distribute the liquid fuel onto the upper surface of the disk of the non-particulate solid reactant 464. At any point where the liquid fuel comes into contact with the disk of the non-particulate solid reactant 464, an exothermic reaction occurs between the liquid fuel and the non-particulate solid reactant.

[0082] Some of the liquid fuel flowing into the sealed package 101 also finds its way down to the bottom of the sealed package 101, where it comes into contact with particulate solid reactants distributed across the open honeycomb network of the lower support structure 462. At any point where the liquid fuel comes into contact with the particulate solid reactants, an exothermic reaction occurs.

[0083] In a typical implementation, heat from one or more exothermic reactions causes the liquid (particularly at the bottom of the sealed package 101) to boil. Boiling creates turbulence that tends to cause the liquid fuel to move gradually upwards from the bottom of the sealed package 101 through the open honeycomb structure of the lower support structure 462, contacting the increasing number of particulate solid reactants embedded in the lower support structure 462. Eventually, the liquid level (and the boiling of the liquid) increases at the bottom of the sealed package 101 to a point where the liquid fuel can reach the bottom of the non-particulate disk of the solid reactants 464. This results in an exothermic reaction occurring at the bottom surface of the non-particulate disk of the solid reactants. At this point, in a typical implementation, heat is generated by the exothermic reactions occurring above and below the non-particulate disk of the solid reactants 464. This generates a large amount of heat very rapidly to heat any product (e.g., food, beverages, etc.) in the product tray 102.

[0084] Several embodiments of the present invention have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of the invention.

[0085] For example, the concept of using a fragile container, including a shrink-film material, to contain liquid reactants can be applied to self-heating containers that rely on the reaction of two liquid reactants to produce an exothermic reaction. In this embodiment, the fragile container (with shrink-film material) can be used to contain either of the liquid reactants in this example. Furthermore, in some such embodiments, a second fragile container (also including shrink-film material) can be used to contain a second liquid reactant.

[0086] In some implementations, in certain fragile container configurations, the moisture barrier material may be located outside the shrink film material, although this is not preferred in most cases.

[0087] In various embodiments, the fragile container may include more than one moisture barrier material and / or more than one shrink film material. In some such cases, each moisture barrier material may be provided as a separate sheet or bag portion, and / or each shrink film material may be provided as a separate sheet or bag portion.

[0088] The self-heating assembly described herein is merely one example of a self-heating container that can use a sealed package. The size, shape, and relative configuration of the various components of a self-heating container can vary considerably. In various embodiments, different types of materials may also be used to form these components.

[0089] For example, in Figures 1 to 3 In the illustrated embodiment, the fragile container is located directly below the bottom of the product tray, the cutting element is located directly below the fragile container, and the sealed package (containing the solid reactant) is located directly below the cutting element. Other related arrangements are also possible. For example, in some embodiments, the cutting element may be located above or to the side of the fragile container. Furthermore, the cutting element may employ methods other than... Figures 1 to 3 The form shown is other than a shaft with a cutting blade. For example, the cutting element may include one or more pins that move axially to pierce the fragile membrane.

[0090] The dimensions and relative configuration of the inner product tray and the outer heater tray can vary considerably. Therefore, the dimensions and shape of the chamber between the inner product tray and the outer heater tray can also vary. The dimensions and shape / configuration of the sealed package can vary considerably. Other aspects of the sealed package can also vary.

[0091] Sealed packages can have any of a variety of different shapes. In some embodiments, for example, the shape can be bowl-shaped or plate-shaped. In other embodiments, the sealed package can be oval or any other shape.

[0092] In some embodiments, all solid reactants may be in particulate form, and no solid reactant is in the disc-shaped, non-particulate configuration described herein. In some of these cases, the amount of particulate solid reactant may be sufficient to fill approximately one-third of the sealed package.

[0093] The lower support structure and / or upper structure can take any of a variety of different forms. For example, in various embodiments, either or both of the lower support structure or upper structure can be open-cell foam, nonwoven materials such as felt, filter pads, quilted tea bag material, deep flocking, water-permeable honeycomb sections, deep pile blankets, tightly sealed short tubes, layered thin paper blocks (e.g., with granules between layers), etc. In some embodiments, including Figures 1 to 3 In the embodiment shown, both layers are open-cell foam.

[0094] In a typical implementation, some particles are held in place by the lower support structure itself. For example, in the case of open-cell foam, some particles may be positioned or wedged into the interior of the open-cell foam and held in place by such wedging. Furthermore, in a typical implementation, the lower support structure is in close physical contact with portions surrounding it (e.g., the sidewalls of the heater tray, the bottom surface of the heater tray, etc.) before the heater is activated. This arrangement helps prevent any loose particles (e.g., particles not held firmly in place by the support structure itself) from migrating throughout the self-heating assembly (e.g., above, below, or to the sides of the support structure).

[0095] An activation device for activating a reaction by breaking a fragile container is described as an external knob connected to an internal shaft having cutting blades that extend radially outward from the shaft, generally parallel to each other. However, the activation device can take any of a variety of different forms. For example, in various embodiments, the activation device can be a sliding element, or a button, or a pair of surfaces, or other means having cutting blades that move into the fragile container when slidable; a button that can be pressed to cause a pin or other cutting blade to enter the fragile container; or a pair of surfaces that can be pushed against each other to compress the fragile container until it breaks. Even, for example… Figure 2 and Figure 3 The activation device shown can also be varied to have more or fewer cutting blades, longer or shorter or different shaped cutting blades, different kinds of external knobs, etc.

[0096] In exemplary embodiments, the first liquid reactant is or contains a fuel (e.g., a polyol fuel, such as ethylene glycol or glycerol), and the second particulate reactant is or contains an oxidant (e.g., an alkali metal permanganate, such as potassium permanganate). In some exemplary embodiments, the first liquid reactant is or contains water, and the second particulate reactant is or contains calcium oxide. Any set of reactants can be used, as long as one reactant is a liquid or slurry that can flow through the upper layer of the sealed package and through the upper and lower support structures to access the other reactant (i.e., the particulate reactant and / or solid disc reactant in the sealed package). In one specific embodiment, the reactants are an aqueous solution of glycerol and potassium permanganate.

[0097] In a typical implementation, the particles of the solid reactant are coated with sodium silicate (water glass) of graded thickness. Because sodium silicate dissolves slowly in hot water, and water is likely the main component of the liquid, varying the thickness of the sodium silicate allows for adjustment of the reaction time between the potassium permanganate particles and the polyol fuel. However, in some implementations, sodium silicate is not present.

[0098] The relative and absolute dimensions of the various subcomponents can vary considerably. Various materials can be adapted to form each subcomponent.

[0099] One or more support structures can actually be any kind of structure capable of performing the functions described herein and belonging to one or more support structures.

[0100] In various implementations, various types of tamper-proof protection can be provided. Generally, tamper-proof protection provides an indication or barrier to entry, and if the indication or barrier is damaged or lost, it is reasonably expected to provide the consumer with visible evidence that tampering has occurred. Examples of tamper-proof protection may include, for example, a breakable tab, a plastic wrapping around the outer portion of the knob assembly, etc.

[0101] Various methods can be used to manufacture a layer of particle-free solid reactants. In one exemplary method, after placing an open-topped outer container (with an internal lower support structure and granular reactants) in a steam-saturated atmosphere for approximately 12 hours, the granules form a rigid cake. These granules are then dried. A second perforated foam disc is then placed on top of the granule mass to provide a fuel flow path at the top, and a lightweight, unglazed paper disc is bonded on top to complete the package. The deliberate use of a fuel flow path on top of the granular cake helps prevent paper and plastic fuel bags from sealing all or part of the granule bed during initial fuel injection.

[0102] It should be understood that any related terms used herein (e.g., “upper,” “lower,” “above,” “below,” “front,” “back,” etc.) are merely intended to clearly describe the particular implementation under discussion and are not intended to limit the scope of the description herein to claim a particular location and / or orientation. Therefore, such related terms should not be construed as limiting the scope of this application. Furthermore, the term “substantially” and similar words are used herein. Unless otherwise stated, “substantially” and similar words should be interpreted broadly as meaning completely and almost completely (e.g., for measurable quantities, this might mean, for example, 99% or more, 95% or more, 90% or more, or 85% or more).

[0103] In some embodiments, the particulate reactants are distributed or dispersed in a substantially uniform manner throughout the lower support structure. This means that the density variation of the particles in multiple equal-volume support structures (e.g., cubic centimeters) does not exceed a certain amount (e.g., 10%, 15%, 20%, etc.). Furthermore, in typical embodiments, the lower support structure supports and substantially maintains the distribution of the particulate reactants throughout the lower support structure before and during the exothermic chemical reaction. In some embodiments, this may mean preventing particle (particulate reactant) displacement to maintain a substantially uniform distribution.

[0104] Self-heating components can be used to heat any of a variety of products, including food, beverages, or non-food items.

[0105] Although this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope that may be claimed, but rather as descriptions of specific features of particular embodiments of a particular invention. Certain features described in the context of individual embodiments may also be implemented in combinations of individual embodiments. Conversely, various features described in the context of individual embodiments may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as functioning in certain combinations and even initially claimed in this way, in some cases, one or more features from the claimed combination may be omitted from the combination, and the claimed combination may be for sub-combinations or variations thereof.

[0106] Similarly, although the operations and / or processes are disclosed herein to occur in a particular order, this should not be construed as requiring these operations to be performed in the particular order shown or in sequence, or requiring all indicated operations to be performed to achieve the desired result.

[0107] Other embodiments also fall within the scope of the claims.

Claims

1. A self-heating component, comprising: Product tray, the product tray being used to hold products to be heated; A heater tray located outside the product tray and configured relative to the product tray to define a reaction space between the heater tray and the product tray; A fragile container, located inside the reaction space, contains a first reactant, which is a liquid. A second reactant, located outside the fragile container, wherein the second reactant undergoes an exothermic reaction upon contact with the first reactant, and A sealed package located inside the heater tray, wherein the sealed package comprises: outer container; A lower support structure, which is located inside the outer container; A layer of solid reactants, the layer of solid reactants being located above the lower support structure and inside the outer container; The upper structure, located above the solid reactant and within the outer container; and The upper layer, which is permeable to liquids, extends across the outer container and is located above the upper structure, forming another open top. The fragile container is made of a material including a shrink film material, and Each of the lower support structure and the upper structure comprises a group of materials selected from open-cell foam, non-woven materials, filter pads, quilted tea bag materials, deep flocking, water-permeable honeycomb sections, deep pile blankets, tightly sealed short tubes, and layered thin paper blocks.

2. The self-heating component according to claim 1, wherein, The fragile container is also made of moisture-barrier material.

3. The self-heating component according to claim 2, wherein, The moisture barrier material forms a moisture barrier bag portion that contains and surrounds the liquid reactant, and wherein the shrink film material forms a shrink film bag portion that contains and surrounds the moisture barrier bag portion.

4. The self-heating component according to claim 2, wherein, The space between the shrink film material and the moisture barrier material is emptied, so that the shrink film material and the entire outer surface of the moisture barrier material are in direct physical contact, and there is no empty space between the shrink film material and the moisture barrier material.

5. The self-heating assembly according to claim 1, wherein, The self-heating assembly also includes an activation device for activating the exothermic reaction by causing the fragile container to break.

6. The self-heating assembly according to claim 5, wherein, The exothermic reaction is initiated by breaking the fragile container to release the first reactant of the liquid from the broken container, causing the first reactant of the liquid to flow downward into the second reactant.

7. The self-heating assembly according to claim 6, wherein, Heat from the exothermic reaction flows upward through the reaction space and over the product tray to heat the product.

8. The self-heating assembly according to claim 7, wherein, The heat from the exothermic reaction reaches the fragile container and causes it to begin to shrink.

9. The self-heating assembly according to claim 8, wherein, The contraction will expel at least a portion of the first reactant remaining in the fragile container from the fragile container.

10. The self-heating assembly according to claim 1, wherein, The shrink film material is selected from the group consisting of polyethylene (PE), polyvinyl chloride (PVC), polyolefin (POF), polyethylene terephthalate (PET), polylactic acid (PLA), and combinations thereof.

11. A method for heating a product, the method comprising: A self-heating component is provided, the self-heating component comprising: Product tray, the product tray being used to hold products to be heated; A heater tray located outside the product tray and configured relative to the product tray to define a reaction space between the heater tray and the product tray; A fragile container located inside the reaction space, wherein the fragile container contains a first reactant, the first reactant being a liquid, and wherein the fragile container is made of a material including a shrink-film material; A second reactant, located outside the fragile container, wherein the second reactant undergoes an exothermic reaction upon contact with the first reactant; an activation device for activating the exothermic reaction by causing the fragile container to break; and A sealed package located inside the heater tray, wherein the sealed package comprises: outer container; A lower support structure, which is located inside the outer container; A layer of solid reactants, the layer of solid reactants being located above the lower support structure and inside the outer container; The upper structure, located above the solid reactant and within the outer container; and The upper layer, which is permeable to liquids, extends across the outer container and is located above the upper structure, forming another open top. Each of the lower support structure and the upper structure comprises a group of materials selected from open-cell foam, non-woven materials, filter pads, quilted tea bag materials, deep flocking, water-permeable honeycomb sections, deep pile blankets, tightly sealed short tubes, and layered thin paper blocks; and The fragile container is broken by manipulating the activation device used to activate the exothermic reaction.

12. The method according to claim 11, wherein, The fragile container is also made of moisture-barrier material.

13. The method according to claim 12, wherein, The moisture barrier material forms a moisture barrier bag portion that contains and surrounds the liquid reactant, and wherein the shrink film material forms a shrink film bag portion that contains and surrounds the moisture barrier bag portion.

14. The method according to claim 12, wherein, The space between the shrink film material and the moisture barrier material is emptied, so that the shrink film material and the entire outer surface of the moisture barrier material are in direct physical contact, and there is no empty space between the shrink film material and the moisture barrier material.

15. The method according to claim 11, wherein, The exothermic reaction is initiated by breaking the fragile container to release the first reactant of the liquid from the broken container, causing the first reactant of the liquid to flow downward into the second reactant.

16. The method according to claim 15, wherein, Heat from the exothermic reaction flows upward through the reaction space and over the product tray to heat the product.

17. The method according to claim 16, wherein, The heat from the exothermic reaction reaches the fragile container and causes it to begin to shrink.

18. The method according to claim 17, wherein, The contraction will expel at least a portion of the first reactant remaining in the fragile container from the fragile container.

19. The method according to claim 11, wherein, The shrink film material is selected from the group consisting of polyethylene (PE), polyvinyl chloride (PVC), polyolefin (POF), polyethylene terephthalate (PET), polylactic acid (PLA), and combinations thereof.

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