ES2745821T3 - Corrugated base susceptor - Google Patents

Abstract

Microwave heating construction (1400; 1500), comprising: a dimensionally stable base (1418a; 1518a) having a first side and a second side opposite the first side, the base including a series of corrugations (1422a; 1522a); a first susceptor layer (1402a; 1502a) attached to the base, the first susceptor layer (1402a; 1502a) being disposed on the first side of the base (1418a; 1518b), the first susceptor layer having a substantially flat configuration, such so that the first susceptor layer extends through the series of corrugations; and a second susceptor layer (1402b; 1502b) attached to the base, the second susceptor layer (1402b; 1502b) being disposed on the second side of the base (1418a; 1518b), the second susceptor layer having a substantially flat configuration of such that the second susceptor layer extends through the series of corrugations, in which the construction including the first susceptor layer and the second susceptor layer is intended to be placed under a food having a lower surface that is desirably, at least, a golden and crisp one, in which at least one of the first susceptor layer and the second susceptor layer includes a central region (1408) that includes a zone transparent to microwave energy (1404; 1504 ) circumscribed by the respective susceptor layer, at least one of the first susceptor layer and the second susceptor layer includes a peripheral region (1410) extending around the central region, inclu the peripheral region being a zone transparent to microwave energy (1406) circumscribed by the respective susceptor layer.

Description

DESCRIPTION

Corrugated base susceptor

TECHNICAL SECTOR

The present invention relates to materials, packages, constructions and systems for heating, browning and / or toasting food in a microwave oven.

STATE OF THE PREVIOUS TECHNIQUE

Microwave ovens provide a convenient means of heating a variety of foods, including sandwiches and other bread and / or dough-based products such as pizzas and empanadas. However, microwave ovens tend to cook such items unevenly and cannot achieve the desired balance of heating inside and a browned, golden crust. US Patent 4,891,482 A discloses a microwave heating construction in the form of a pizza box formed from a base piece including a microwave susceptor. The box includes a second separate microwave susceptor sheet on the bottom thereof, and the box is placed on a spacer element such that both suspensors are arranged on the top side of the spacer element. Thus, there is a continuing need for improved materials, packages, and other constructions that provide the desired degree of heating, browning, and / or browning of various foods in a microwave oven.

FEATURES

This objective is solved by a microwave heating construction according to claim 1 and the claims dependent on it.

The present invention relates, in general, to various microwave energy interactive structures according to the invention and not according to the invention that can be used to form covers, discs, trays, cardboard boxes, packages and other constructions (together , "Constructions") to improve the heating, browning and / or roasting of a food in a microwave oven. The various structures generally comprise a series of components or layers assembled and / or joined together in a configuration of facing layers, substantially in contact. The layers include at least two microwave-interactive elements and a dimensionally stable base. Each microwave energy interactive element comprises one or more microwave energy interactive components or segments, arranged in a particular configuration to absorb microwave energy, transmit microwave energy, reflect microwave energy or direct microwave energy as needed or desired for a particular microwave heating application. Each of the microwave energy interactive elements comprises a susceptor. The susceptor can circumscribe one or more transparent areas to the microwave energy that allow the microwave energy to pass through the respective susceptor layer.

The base, in general, can provide thermal insulation between the microwave energy interactive element and the heating environment. In one example, the base comprises corrugated paper or cardboard, and the frame is a thermally insulated susceptor frame.

It has been found that using more than one susceptor with an insulating base to form a thermally insulated susceptor structure significantly improves heating, browning, and browning of a food therein compared to (1) a structure that includes more of a susceptor layer without a thermally insulating base, or (2) a single susceptor that covers a thermally insulating base. If necessary or at least desired, an opening or cut can be extended through one or more layers of the structure, to provide direct heating and / or ventilation to the bottom surface of the food.

Thus, according to the present invention, a thermally insulated susceptor structure comprises a dimensionally stable base having a first side and a second side opposite to the first side, a first susceptor arranged on the first side of the base, and a second susceptor arranged on the second side of the base. The base includes a series of corrugations. The first susceptor, the second susceptor, or both the first and the second susceptor can circumscribe at least one area transparent to microwave energy.

In each of several independent examples, the first susceptor and / or the second susceptor can be supported on a layer of polymer film and / or can be attached to a respective support layer, for example, paper. The various layers can be arranged in numerous ways in the structure of the susceptor. The structure may also include one or more additional layers, for example, paper layers, polymer film layers, susceptor layers, and / or corrugated layers.

Any such structure can be used to form a construction for heating, browning and / or toasting a food in a microwave oven. In one example, a microwave heating construction comprises a dimensionally stable corrugated base, a first susceptor layer and a second susceptor layer, including at least one of the first susceptor layer and the second susceptor layer a central region including, at least one microwave energy transparent zone circumscribed by the respective susceptor layer, and including at least one of the first susceptor layer and the second susceptor layer a peripheral region including at least one zone transparent to microwave energy circumscribed by the respective susceptor layer.

One or both of the susceptor layers can include the various microwave energy transparent zones, such that the first susceptor layer can include both the central region and the peripheral region, the second susceptor layer can include both the central region and the region peripheral, both the first and second susceptor layers can include a respective central region and peripheral region, or one susceptor layer can contain one region, while the other susceptor layer can include the other region.

In a specific example, the microwave energy transparent zones in the central region have a substantially circular shape, with a greater number of microwave energy transparent zones close to the center of the construction, and the transparent zones to the Microwave energy in the peripheral region is substantially square in shape. However, numerous additional arrangements of microwave-interactive zones are contemplated.

Various aspects, features and advantages of the invention will become apparent from the following description and the attached figures. Although various different aspects, implementations, and embodiments of the invention are disclosed, numerous interrelationships, combinations, and modifications of the various aspects, implementations, and embodiments of the invention are contemplated.

BRIEF DESCRIPTION OF THE DRAWINGS

The description refers to the attached drawings, which show reference examples not according to the invention, as well as embodiments of the invention in which the similar reference characters refer to similar parts in the various views, and in which:

Figures 1 to 11 are schematic cross-sectional views of various structures interactive with microwave energy, by way of example and not according to the invention;

Fig. 12 is a schematic perspective view of a microwave energy interactive heating disc that may be formed from a microwave energy interactive structure not according to the invention;

Figure 13 is a schematic perspective view of a microwave energy interactive heating tray not according to the invention, which may be formed from a microwave energy interactive structure;

Figure 14A is a schematic top plan view of a microwave heating construction according to the invention that includes microwave energy transparent areas;

Figure 14B is a schematic cross-sectional view of a part of the construction according to the invention of Figure 14A;

Figures 15 and 16 are schematic cross-sectional views of alternative microwave heating constructions according to the invention (Figure 15) and not according to the invention (Figure 16), optionally including the arrangement of energy-transparent zones of the microwaves of Figure 14A; Y

Figure 17 is a schematic top plan view of a commercially available microwave energy interactive heating disc evaluated for comparative purposes; Y

Figures 18 to 20 are schematic top plan views of other microwave energy interactive heating discs not according to the invention, evaluated according to the invention.

DESCRIPTION

The present invention generally relates to various microwave energy interactive structures that can be used to form microwave heating packs or other constructions that improve heating, browning and / or toasting of a food in a microwave. Each of the various structures includes a pair of microwave energy interactive elements that cover at least one dimensionally stable (eg, rigid or semi-rigid) part of a base.

One or both microwave energy interactive elements may comprise a thin layer of microwave energy interactive material (ie, a "susceptor") (generally less than about 10nm (100 angstroms) thick , for example, between about 6 nm to 10 nm (between 60 angstroms and about 100 angstroms) thick) that tends to absorb at least part of the microwave energy and convert it into thermal energy (it is say heat) at an interface with a food. The susceptor may be supported on a microwave-transparent substrate, for example, a layer of paper or polymer film, to facilitate handling and / or to avoid contact between interactive material with microwave energy and food. Often, susceptor elements are used to promote browning and / or browning of the surface of a food. However, other interactive elements can be used with microwave energy.

The base, in general, can provide thermal insulation between the microwave energy interactive element and the heating environment. In one example, the base comprises corrugated or corrugated paper or cardboard. However, other materials can be used that provide an insulating or void space that can reduce undesirable heat transfer to the exterior of the microwave energy interactive element. It will be appreciated that numerous structures having different configurations can be formed with such materials, and structures of this type are contemplated.

A construction formed from a structure that includes more than one susceptor layer and one layer of corrugated insulating material has been found to significantly improve heating, browning and / or browning of a food compared to (1) a structure that includes more than one susceptor layer without a corrugated base, or (2) a single susceptor that covers a corrugated base. When the construction is exposed to microwave energy, the susceptor layers convert at least a portion of the incident microwave energy into thermal energy, which then heats the adjacent food, and in some cases, the air inside the grooves and / or the other layer or the other susceptor layers. As a result, the heating, browning and / or browning of the food can be significantly improved. Additionally, although not intended to be limited by theory, it is believed that air and other gases between the corrugated base grooves provide insulation between the food and the microwave oven environment, thereby increasing the amount of sensible heat that is remains inside or is transferred to food. Some structures may also include openings that allow moisture to be released from the food, thereby improving browning and / or browning of the food.

Various aspects of the invention can be shown with reference to the figures, in which various exemplary constructions are schematically represented. For simplicity, similar numbers can be used to describe similar characteristics. It will be understood that when a series of similar characteristics are represented, not all of these characteristics are necessarily labeled in each figure. While various exemplary embodiments are shown and described herein in detail, it will also be understood that any one of the features can be used in any combination, and that such combinations are contemplated by the invention.

FIG. 1 depicts a schematic, cross-sectional view of an exemplary microwave energy interactive structure 100. Structure 100 includes a pair of microwave energy interactive elements 102a, 102b, eg, susceptors, supported on respective microwave energy transparent substrates 104a, 104b, eg, layers of polymer film, to define together the respective susceptor films or susceptor film layers 106a, 106b. Each susceptor film 106a, 106b is attached, respectively, to a microwave energy transparent, dimensionally stable support or support layer 108a, 108b, eg paper. The support layers 108a, 108b are attached to opposite sides of a dimensionally stable corrugated base 110.

In this example, base 110 is a double-sided corrugated material comprising a series of grooves 112 joined on opposite surfaces by a pair of substantially flat liner layers 114a, 114b, thereby defining a series of voids or spaces 116 insulators between the grooves 112 and the cladding layers 114a, 114b. It is observed that, in the various figures, the grooves or corrugations of the insulating base have a more angular, sawtooth shape. However, it will be understood that said figures are only schematic, and that the various grooves may have a more rounded sinusoidal shape.

Not all of these layers may be necessary for a particular microwave heating application. Furthermore, in some cases, the layers of the structure can be rearranged without adversely affecting the heating, browning and / or browning capabilities of the structure. For example, Figures 2 to 6 schematically depict various exemplary variations of the microwave energy interactive structure 100 of Figure 1, each including two susceptor layers and an insulating base. The various structures 200, 300, 400, 500, 600 include features that are similar to structure 100 shown in Figure 1, except for the observed variations and variations that will be understood by those skilled in the art. For simplicity, reference numbers with similar characteristics are preceded in the figures by a "2" (figure 2), "3" (figure 3), "4" (figure 4), "5" (figure 5) or " 6 ”(figure 6), instead of a“ 1 ”.

By way of example, Figure 2 shows a microwave energy interactive structure 200, by way of example, which is similar to structure 100 of Figure 1, except that structure 200 of Figure 2 includes a corrugated base Single-sided 210 comprising a substantially flat liner or layer (or "flat side") 214a and a corrugated or ribbed structure or layer ("ribbed side") 212 opposite flat plane 214a. The susceptor film 206b and the support 208b are attached to the grooves in a substantially flat configuration such that the susceptor film 206b and the support 208b extend through the grooves and are at least partially attached to the points more external of the same (that is, through the axes of the grooves and along them). The insulating voids 216 are between substrate 204b and corrugations 212.

FIG. 3 shows an exemplary structure 300 without the support layers 108a, 108b of FIG. 1. In this example, the susceptor films 306a, 306b are directly bonded to the liner layers 314a, 314b of the corrugated base 310 In contrast, Figure 4 shows an exemplary structure 400 with a corrugated base 410 without a liner. In this example, the grooves 412 are attached directly to the support layers 408a, 408b, thereby defining the insulating voids 416. The relative positions of the susceptor film 406b and the support 408b are observed to be inverted with respect to the susceptor film 106b and support 108b of FIG. 1. This can simplify construction, for example, in which corrugated structure 412 and support 408b are each formed of paper, and said layers are adhesively bonded together. However, it is contemplated that the layers may be configured with support 408b on the exterior of structure 400. It is also noted that since layers 314a, 314 and layers 408a, 408b can be formed from similar materials ( eg paper), the structures of Figures 3 and 4 may be similar in form and / or function. However, both structures 300, 400 are shown schematically herein for clarity and completeness. The concrete construction selected for a given application may depend on the materials available, the capabilities of the process and / or the machinery used to form the structure, and / or numerous other factors.

If desired, any of the various structures may include one or more openings or cutouts that extend through all or a portion of one or more layers. Said openings can have any shape and / or configuration and can be used for various purposes, as will be explained in more detail below. For example, structure 500 of FIG. 5 is similar to structure 400 of FIG. 4, except that the corrugated base 510 has a single liner layer 514b. A series of openings or slits 518 extend through the first susceptor film 506a and the support 508a, thereby exposing the corrugations or grooves 512 and the insulating voids 516. If desired, the support layer 504a can serve as a food contact layer or surface in open communication with insulating voids 516 through openings 518. In such examples, moisture generated by the food can pass through openings 518 into voids 516, which can serve as ventilation channels that release moisture from the food to further enhance browning and / or browning of the food.

Figure 6 schematically represents another structure 600 interactive with microwave energy. In this example, structure 600 is similar to structure 200 in FIG. 2, except that structure 600 in FIG. 6 includes a series of openings or slits 618 that extend through the first susceptor film 606a and support 608a. , thereby exposing front 614 of base 610. In this example, openings 618 can provide browning marks that create the impression of heating on a griddle or grill, and can also provide some release of moisture from the food.

In some examples, the structure may include one or more susceptor layers, susceptor film layers, and / or support layers that directly coat the faces of the grooves or corrugations in a substantial contact relationship, such that the particular susceptor layer, the layer of susceptor film and / or the support layer is also corrugated or ribbed. For example, Fig. 7 schematically depicts an exemplary microwave energy interactive structure 700 including a first susceptor film 706a, attached to a first support layer 708a, a second susceptor film 706b, covering the ribbed or corrugated side of a single-sided corrugated base 710, and a third susceptor film 706c, attached to a second support layer 708c. Each of the susceptor films 706a, 706b, 706c comprises a respective layer of microwave energy interactive material 702a, 702b, 702c supported on a respective substrate 704a, 704b, 704c. The base 710 comprises a liner layer 714 and a series of grooves 712. The second susceptor film 706b is corrugated and covers the grooves 712. The insulating voids 716 lie between the support layer 708a and the grooves 712 and between the layer 714 and the grooves 712.

Figures 8 to 12 schematically represent some exemplary variations of the microwave energy interactive structure 700 of Figure 7. The various structures 800, 900, 1000, 1100, 1200 include features that are similar to structure 700. shown in Figure 7, except for the observed variations and variations that those skilled in the art will understand. For simplicity, reference numbers with similar characteristics are preceded in the figures by an "8" (figure 8), "9" (figures 9A and 9B), "10" (figure 10) or "11" (figure 11) instead of a "7".

Structure 800 of FIG. 8 is similar to structure 700 of FIG. 7, except that structure 800 of FIG. 8 does not include a third susceptor film 706c and support 708c. Additionally, in this example, a series of openings or slits 818 extend through the first susceptor film 806a and the support 808a, such that the apertures 818 are in open communication with the voids 816 and the second susceptor film 806b. covering base 810. In some cases, voids 816 can serve as ventilation channels to enhance browning and / or browning of a food.

Structure 900 of FIG. 9A is similar to structure 800 of FIG. 8, except that the susceptor layer 806b and the corrugated base 810 are inverted such that the liner layer 914 is bonded to the first support layer 908a. . In this configuration, the substrate layer 904a can comprise a food contact surface. With the structure 900 inverted, as shown in Figure 9B, the substrate 904b can comprise a food contact surface. In this latter configuration, openings 918 are located on the underside of structure 900 contiguous to the floor of the microwave oven. Openings 918 can provide a thermal insulation benefit and / or can improve air circulation around structure 900.

Fig. 10 schematically shows yet another interactive microwave energy structure 1000, by way of example. Structure 1000 is similar to structure 900 in Figure 9A, without openings 918. Figure 11 is similar to structure 1000 in Figure 10A without support layer 1008a.

The various structures shown herein and / or contemplated herein can be used to form numerous constructs for heating, browning, and / or toasting food in a microwave oven. For example, Figure 12 depicts an exemplary 1200 microwave-interactive construction (eg, a disk) having a substantially circular heating surface 1202 (shown schematically by stippling in Figures 12 and 13). ) suitable for heating, for example, a pizza, panini or other circular food in it. If desired, the edges of disk 1200 can be turned to form a tray 1300 having a peripheral area or an overturned side wall 1302 surrounding a heating surface 1304, as shown schematically in Figure 13. A tray 1300 of this type (and many others) can be formed, for example, using conventional thermal and / or mechanical press forming equipment. However, the various microwave energy interactive structures can be used to form all or part of any type of construction, for example, a package, a cardboard box, a disk, a tubular element, a bag, a platform etc. Any such construction may have any suitable shape, for example, square, rectangular, triangular, oval, or any other regular or irregular shape.

The invention contemplates innumerable additional structures and constructions interactive with microwave energy. As indicated above, any one of these structures can include one or more zones that are transparent to microwave energy. Such microwave energy transparent zones transmit microwave energy and, in some cases, can cause localized electric fields to form which improve heating, browning and / or toasting of an adjacent food. The transparent areas can be dimensioned, positioned and / or organized to personalize the heating, browning and / or toasting of a specific area of the food to be heated.

For example, Figure 14A schematically shows a top plan view of a microwave heating construction 1400 (eg, a microwave heating disc) according to the invention, which generally includes a susceptor 1402 (shown with dotted) that circumscribes a series of transparent areas for microwave energy 1404, 1406 (shown in white). In this example, disc 1400 has a substantially circular shape. However, any regular or irregular shape can be used.

Disc 1400 includes a central region 1408 and a peripheral region 1410. In the central region 1408 of disc 1400, transparent areas 1404 are substantially circular in shape, decreasing the concentration of transparent areas to microwave energy 1404 from the center of the disc 1400 outward, toward peripheral region 1410. However, other configurations are contemplated. In the peripheral region 1410, the microwave energy transparent regions 1406 are substantially square in shape and arranged in rows and columns, such that the microwave energy interactive material in the peripheral region has an appearance of grill. As stated above, the percentage of clear zone may vary as necessary to achieve the desired heating, browning, and / or roasting of the food. Such zones can be formed in any suitable way, as will be described below.

FIG. 14B schematically shows a cross-sectional view of a portion of the microwave heating disc 1400 of FIG. 14A. Microwave heating disc 1400 includes a pair of microwave energy interactive elements 1402a, 1402b, eg, susceptors, supported on respective microwave energy-transparent substrates 1412a, 1412b, eg, film layers of polymer, to together define respective susceptor films or susceptor film layers 1414a, 1414b. Each susceptor film 1414a, 1414b is attached, respectively, to a microwave energy transparent, dimensionally stable support or backing layer or support, 1416a, 1416b, eg, paper. The support layer 1416a is attached to the grooved side of a single-sided corrugated material 1418a, thereby defining a series of voids or insulating spaces 1420a between the grooves 1422a and the support layer 1416a, while the substrate layer 1412b is attached to face 1424a of corrugated material 1418a. Susceptor 1402a circumscribes at least one, and, in some examples, a series of microwave-transparent (ie, inactive) energy zones 1404 (or 1406, Figure 14A).

Figures 15 and 16 schematically represent exemplary variations of the microwave energy interactive disk 1400 of Figures 14A and 14B. The microwave heating discs 1500, 1600 may include features that are similar to the disc 1400 shown in Figures 14A and 14B, except for the observed variations and variations that will be understood by those skilled in the art. For simplicity, reference numbers with similar characteristics are preceded in the figures by a "15" (figure 15) or "16" (figure 16).

In the example shown in FIG. 15, the microwave heating disc 1500 includes an additional layer of corrugated material 1518b, the grooves 1522b being attached to the support layer 1516b to define additional insulating voids 1520b, adjacent to the grooves 1522b.

In the example shown in Figure 16, the susceptor film 1614b and the support 1614b are disposed between the support layer 1616a and the grooves 1622a of the corrugated material 1618a.

Numerous other structures and constructions are encompassed by the invention. Any of the structures described herein or contemplated herein may be formed from various materials, provided that the materials are substantially resistant to softening, scorching, burning or degradation at the usual heating temperatures in a microwave oven. typical, for example, comprised between about 121.1 ° C (250 ° F) and about 218.3 ° C (425 ° F). The particular materials used may include microwave energy interactive materials, for example, those used to form microwave energy interactive susceptors and other elements, and materials that are transparent or inactive to microwave energy, for example, used to form the base, substrate and support layers.

The microwave energy interactive material can be an electroconductive or semiconductor material, for example a metal or metal alloy arranged as a metal foil; or a vacuum deposited metal or metal alloy; or a metallic ink, an organic ink, an inorganic ink, a metallic paste, an organic paste, an inorganic paste, or any combination thereof. Examples of metals and metal alloys that may be suitable include, aluminum, chrome, copper, inconel alloys (nickel-chromium-molybdenum alloy with niobium), iron, magnesium, nickel, stainless steel, tin, titanium, tungsten, and any combination thereof, but are not limited to them.

Alternatively, the microwave energy interactive material may comprise a metal oxide. Examples of metal oxides that may be suitable include, but are not limited to, aluminum oxides, iron and tin, which are used in conjunction with an electrically conductive material when necessary. Another example of a metal oxide that may be suitable is indium tin oxide (ITO). ITO can be used as an interactive material with microwave energy to provide a heating effect, a protection effect, a browning and / or browning effect, or a combination thereof. For example, to form a susceptor, ITO can be sprayed onto a clear polymer film. The sputtering process generally occurs at a lower temperature than the evaporative deposition process used for metal deposition. ITO has a more uniform crystalline structure and is therefore transparent in most coating thicknesses. Additionally, the ITO can be used for heating purposes or field management. ITO can also have fewer defects than metals, making ITO thick coatings more suitable for field management than thick metal coatings, such as aluminum.

Still alternatively, the microwave energy interactive material may comprise a suitable electroconductive, semiconductor or non-conductive artificial dielectric or ferroelectric. Artificial dielectrics comprise conductive material subdivided into a suitable polymeric or other matrix or binder, and may include flakes of an electrically conductive metal, for example, aluminum.

While susceptors are described in detail herein in the exemplary constructions, the microwave energy interactive element, alternatively or additionally, may comprise a sheet that is thick enough to protect one or more portions. selected from the microwave energy food. Such "protection elements" can be used where the food is prone to scorch or dry out during heating.

The protection element can be formed from various materials and can have various configurations, depending on the specific application for which the protection element is used. Typically, the protective element is formed from a reflective, conductive metal or metal alloy, for example, aluminum, copper, or stainless steel. The protection element, in general, can have a thickness between approximately 0.0007239 cm (0.000285 inches) and approximately 0.127 cm (0.05 inches). In one example, the protective element may be between about 0.000762 cm (0.0003 inch) and about 0.0762 cm (0.03 inch) in thickness. In another example, the protection element may have a thickness of between about 0.000889 cm (0.00035 inches) and about 0.0508 cm (0.020 inches), for example, about 0.04064 cm (0.016 inches).

As a further example, the microwave energy interactive element may comprise a segmented sheet, such as, among others, those described in US Patent Nos. 6,204,492, 6,433,322, 6,552,315 and 6,677,563. Although the segmented sheets are not continuous, the appropriately separated groupings of said segments can act as a protection element. Such sheets can also be used in combination with susceptor elements and, depending on the configuration and positioning of the segmented sheet, the segmented sheet can function to direct microwave energy and promote heating rather than protect from energy from microwave oven.

If desired, any of the numerous microwave energy interactive elements described herein or contemplated herein may be substantially continuous, i.e. without substantial interruptions or breaks, or may be discontinuous, for example, including one or more interruptions or openings that transmit microwave energy through them. The interruptions or openings can be dimensioned and positioned to selectively heat specific areas of the food. Interruptions or openings can extend throughout the structure, or only through one or more layers. The number, shape, size and position of these interruptions or openings may vary for a specific application, depending on the type of construction being formed, the food to be heated or the desired degree of protection, browning and / or toasting. , whether direct exposure to microwave energy is needed or desired to achieve uniform heating of the food, the need to regulate the change in temperature of the food through direct heating, and whether there is a need for ventilation and to what extent.

It will be understood that the opening may be a physical opening or an empty space in one or more layers or materials used to form the construction (see, for example, 518, 618, 818, 918; Figures 5, 6, 8, 9A, 9B ), or it may be a non-physical "opening" (see, eg, 1404, 1406, 1504, 1604; Figures 14A to 16). A nonphysical opening is a microwave energy transparent zone that allows microwave energy to pass through the structure without an actual void space or hole cut through the structure. Such zones may be formed simply by not applying a microwave energy interactive material to the particular zone, or removing microwave energy interactive material in the concrete zone, and / or chemically and / or mechanically deactivating the interactive material with microwave energy in the specific area. Although physical and non-physical openings allow food to be heated directly by microwave energy, a physical opening also provides a ventilation function, to allow steam or other vapors to escape from inside the building. It will be appreciated that when chemical deactivation is used, the metal in the deactivated zone can be chemically altered, for example oxidized, such that the non-physical opening comprises a chemically altered, but energy-transparent form of metal. microwave oven.

As indicated above, any of the microwave energy interactive elements may be supported on a substrate comprising a polymer film or other suitable polymeric material. As used herein, the term "polymer" or "polymeric material" includes homopolymers, copolymers, such as, for example, block, graft, random and alternate copolymers, terpolymers, etc. and mixtures and modifications thereof, but not limited to them. Furthermore, unless otherwise specified, the term "polymer" will include all possible geometric configurations of the molecule. These configurations include, but are not limited to, isotactic, syndiotactic, and random symmetries.

Examples of polymeric films that may be suitable include, but are not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, polymeric films that may be suitable are: Also, other non-conductive substrate materials can be used, such as paper and paper laminates, metal oxides, silicates, cellulosics, or any combination thereof.

In a specific example, the polymer film comprises polyethylene terephthalate. Examples of polyethylene terephthalate films that may be suitable for use as a substrate include, but are not limited to, MELINEX®, marketed by DuPont Teijan Films (Hopewell, Virginia) and SKYROL, marketed by SKC, Inc. (Covington, Georgia). Polyethylene terephthalate films are used in commercially available susceptors, for example, the Focus QWIKWAVE® susceptor and the MICRORITE® susceptor, sold by Graphic Packaging International (Marietta, Georgia).

The thickness of the film can generally be between about 8.89 pm (35 gauges) and about 0.254 mm (10 thousandths of an inch). In one example, the thickness of the film can be between about 10.16 pm and about 20.32 pm (between about 40 gauges and about 80 gauges). In another example, the thickness of the film is between about 11.43 pm and about 12.7 pm (between about 45 gauges and about 50 gauges). In another example, the thickness of the film is approximately 12,192 pm (48 gauges).

Microwave energy interactive material can be applied to the substrate in any suitable way and, in some cases, microwave energy interactive material is printed, extruded, deposited, evaporated, or layered on the substrate. Microwave energy interactive material can be applied to the substrate in any configuration, and using any technique, to achieve the desired heating effect of the food.

For example, the microwave energy interactive material can be arranged as a continuous or discontinuous layer or coating including circles, loops, hexagons, islands, squares, rectangles, octagons, etc. Examples of various patterns and methods that may be suitable are disclosed in United States Patents N26,765,182; 6,717,121; 6,677,563; 6,552,315; 6,455,827; 6,433,322; 6,414,290; 6,251,451; 6,204,492; 6,150,646; 6,114,679; 5,800,724; 5,759,422; 5,672,407; 5,628,921; 5,519,195; 5,424,517; 5,410,135; 5,354,973; 5,340,436; 5,266,386; 5,260,537; 5,221,419; 5,213,902; 5,117,078; 5,039,364; 4,963,424; 4,936,935; 4,890,439; 4,775,771; 4,865,921; and Re. 34,683. Although specific examples of microwave energy interactive material patterns are shown and described in the present invention, it should be understood that the present invention contemplates other microwave energy interactive material patterns.

Various corrugated materials can be used to form an interactive structure with microwave energy. Corrugated materials have a longitudinal direction, which extends along the length of the grooves, and a transverse direction, which passes through the grooves. Corrugated materials can be relatively stiff when the material is flexed in the longitudinal direction, and relatively flexible when it is flexed in the transverse direction. Therefore, it is contemplated that structural elements can be added to improve the rigidity of the construction. To the contrary, it is also contemplated that the construction may include elements that weaken the structure, for example, a score line, if necessary or desired for a particular application. Single-sided corrugated materials that may be suitable include but are not limited to groove sizes A, B (154 grooves / linear m (47 grooves / linear foot)), E (295 grooves / linear m (90 grooves / linear foot) ), or any other size. Corrugated double-sided materials that may be suitable include but are not limited to groove sizes B, C, E, and F.

Various materials can be used to form the support. For example, all or part of the support may be formed, at least partially, from a paper or cardboard material. In one example, the support is formed from paper that generally has a weight of between approximately 24.4125 g / m2 and approximately 97.65 g / m2 (comprised between approximately 15 lb / ream and 60 lb / ream (lb / 3,000 square feet), for example, between about 32.55 g / m2 and about 65.1 g / m2 (between about 20 lb / ream and 40 lb / ream.) In another example, the paper has a grammage of approximately 40.6875 g / m2 (25 lb / ream). In another example, the support is formed from cardboard, which has a grammage of between approximately 97.65 g / m2 and approximately 537.075 g / m2 ( ranging from 60 lb / ream to 330 lb / ream), for example, ranging from about 130.2 g / m2 to about 227.85 g / m2 (ranging from 80 lb / ream to 140 lb / ream). , the cardboard can have a thickness between approximately 0.1524 mm and approximately 0.762 mm (between 6 thousandths of a flea da and 30 thousandths of an inch), for example, comprised between approximately 0.3048 mm and approximately 0.7112 mm (comprised between approximately 12 thousandths of an inch and 28 thousandths of an inch). In one concrete example, the cardboard is approximately 0.304848 mm (12 thousandths of an inch) thick. Any suitable board can be used, for example, a solid bleached or unbleached sulfate board, such as a SUS® board, available from Graphic Packaging International.

As a further example, the support may be formed, at least partially, from a polymer or polymeric material. A polymer that may be suitable is polycarbonate. Other examples of other polymers that may be suitable include, polyolefins, for example, polyethylene, polypropylene, polybutylene, and copolymers thereof; polytetrafluoroethylene; polyesters, for example, polyethylene terephthalate, for example, co-extruded polyethylene terephthalate; vinyl polymers, for example, polyvinyl chloride, polyvinyl alcohol, vinyl ethylene alcohol, polyvinylidene chloride, polyvinyl acetate, polyvinyl chloride acetate, polyvinyl butyral; acrylic resins, for example, polyacrylate, polymethylacrylate and polymethylmethacrylate; polyamides, for example nylon 6,6; polystyrene; polyurethanes; cellulosic resins, for example cellulosic nitrate, cellulosic acetate, cellulosic acetate butyrate, ethyl cellulose; copolymers of any of the above materials; or any mixture or combination thereof, but not limited to them.

The various constructions can be formed according to numerous processes known to those skilled in the art, including the use of an adhesive bond, a thermal bond, an ultrasonic bond, a mechanical stitch or any other suitable process. Any of the various layers that can be used to form the constructions can be a sheet of material, a roll of material, or a die-cut material in the form of the construction to be formed.

Optionally, one or more panels of the various constructions described herein or contemplated herein may be coated with varnish, clay, or other materials, either alone or in combination. The overlay can be printed with product advertising or other information or images. Constructions can also be coated to protect any information printed on them. Furthermore, the constructions can be covered, for example, with a moisture barrier layer, in one or both sides.

Alternatively or additionally, any of the structures or constructions may be coated or laminated with other materials to print other properties, such as absorption, repellency, opacity, color, printability, stiffness or damping. For example, absorbent susceptors are described in United States Provisional Patent Application No. 60 / 604,637, filed August 25, 2004, and in United States Patent Application Publication No. US 2006/0049190 A1, published on March 9, 2006. Additionally, structures or constructions may include graphics or signs printed on them.

Various aspects of the invention can be better understood from the following examples, which are not intended to be limiting in any way.

EXAMPLES 1 to 7

Panini sandwiches marketed by the Nestlé firm were heated to evaluate the performance of various constructions according to the invention. Each panini sandwich was placed on the construction being evaluated, placed in a microwave oven marketed by the 1100 W Panasonic firm, with a turntable and heated at full power for approximately 8 minutes. The results are presented in Table 1, which describes the various layers of constructions from the food contact side with the microwave oven side. It will be understood that when a metallized film (i.e., a susceptor film) forms an outermost layer of the construction, the metallized side of the susceptor film faces inward, and the polymer film faces outwardly.

Table 1.

EXAMPLES 8 to 11

Commercially available 22.86 cm (9 inch) diameter frozen deluxe Tombstone pizzas were heated to evaluate the performance of various constructions according to the invention. Each pizza was placed on top of the construction being evaluated, placed in a microwave oven marketed by the 1100 W Panasonic firm, with a turntable and heated at full power for approximately 8 minutes. The results are presented in Table 2.

Table 2.

Namely, the construction of Example 10 was significantly heated under the pizza compared to the construction of Example 8, however, the outer edges outside the pizza were not scorched. Therefore, the Example 10 construction showed a higher heating power, but a smoother heating than the Example 8 construction. The Example 11 construction warmed up more when exposed to microwave energy. Therefore, more susceptor layers can be used when it is desirable to reach higher temperatures to brown and / or toast the food.

EXAMPLES 12 to 13

Commercially available 25.4 cm (10 in) diameter frozen deluxe Tombstone pizzas were heated to evaluate the performance of various constructions according to the invention. Each pizza was placed on top of the construction being evaluated, placed in a microwave oven marketed by the 1100 W Panasonic firm, with a turntable and heated at full power for approximately 8 minutes. The results are presented in Table 3.

Table 3.

Although certain embodiments have been described with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the invention as defined in the claims. All directional references (for example, higher, lower, up, down, left, right, left, right, top, bottom, above, below, vertical, horizontal, clockwise, and clockwise counterclockwise) are used for the purpose of identification only, to assist the reader in understanding the various embodiments of the present invention, and do not create limitations, specifically as to the position, orientation, or use of the invention, unless specifically indicated. in the claims. Joint references (eg, joined, fixed, coupled, connected, and the like) are to be interpreted broadly and may include elements intermediate between a connection of elements and the relative movement between the elements. Therefore, joint references do not necessarily imply that two elements are connected directly and in a fixed relationship to each other.

Those skilled in the art will recognize that various elements explained with reference to the various embodiments can be interchanged to create entirely new embodiments of the invention. All material contained in the foregoing description or shown in the accompanying drawings is intended to be construed as illustrative and not limiting. Changes in detail or structure can be made without departing from the invention as defined in the claims. The detailed description indicated herein is not intended and should not be construed as limiting the invention or otherwise excluding any other embodiment, adaptation, variation, modification and equivalent arrangement of the invention.

Accordingly, those skilled in the art will readily understand that, in view of the foregoing detailed description of the invention, the invention is capable of wide utility and application. Many adaptations of the invention other than those set forth herein will become apparent, as well as many variations, modifications, and equivalent arrangements reasonably suggested by the invention and by the foregoing detailed description thereof, without departing from the invention as is. defined in the claims.

Although the present invention is described herein in detail in relation to specific aspects or embodiments, it will be understood that this detailed description is illustrative and exemplary of the invention only, and is performed for the purpose of providing a complete description and that it is merely allow the invention to be put into practice. The detailed description set forth herein should not be construed as limiting the invention or otherwise excluding any of said other embodiments, adaptations, variants, modifications and equivalent arrangements of the invention.

Claims (13)

1. Construction for microwave heating (1400; 1500), comprising: a dimensionally stable base (1418a; 1518a) having a first side and a second side opposite the first side, the base including a series of corrugations (1422a; 1522a); a first susceptor layer (1402a; 1502a) attached to the base, the first susceptor layer (1402a; 1502a) being disposed on the first side of the base (1418a; 1518b), the first susceptor layer having a substantially flat configuration, such so that the first susceptor layer extends through the series of corrugations; Y a second susceptor layer (1402b; 1502b) attached to the base, the second susceptor layer (1402b; 1502b) being disposed on the second side of the base (1418a; 1518b), the second susceptor layer having a substantially flat configuration, such so that the second susceptor layer extends through the series of corrugations, wherein the construction including the first susceptor layer and the second susceptor layer is intended to be placed under a food having a bottom surface that is desirably at least one of a crisp, golden brown, in which at least one of the first susceptor layer and the second susceptor layer includes a central region (1408) that includes a microwave-transparent zone (1404; 1504) circumscribed by the respective susceptor layer, at least one of the first susceptor layer and the second susceptor layer includes a peripheral region (1410) extending around the central region, the peripheral region including a microwave energy transparent zone (1406) circumscribed by the susceptor layer respective. 2. Construction according to claim 1, in which the microwave energy transparent zone (1404; 1504) of the central region (1408) has a substantially circular shape. 3. Construction according to claim 1 or 2, in which the microwave energy transparent zone (1406) of the peripheral region (1410) has a substantially square shape. 4. Construction according to any of claims 1 to 3, wherein the microwave energy transparent zone (1404; 1504) of the central region (1408) is a first microwave energy transparent zone of a series of microwave energy transparent zones of the central region, and The microwave energy transparent zone (1406) of the peripheral region (1410) is a first microwave energy transparent zone of a series of microwave energy transparent zones of the peripheral region. Construction according to claim 4, in which the microwave energy transparent zones (1404; 1504) of the central region (1408) are arranged with a greater number of microwave energy transparent zones close to the construction center. 6. Construction according to claim 4 or 5, in which the microwave energy transparent zones (1406) of the peripheral region (1410) are arranged in rows and columns, such that the energy interactive material of the microwaves in the peripheral region has a grill appearance. 7. Construction according to any of claims 1 to 6, wherein the first susceptor layer (1402a; 1502a) is disposed between a first layer of polymer film (1412a, 1512a, 1612a) and a first layer of paper (1416a; 1516a) in a coating and contact relationship, and the second susceptor layer (1402b; 1502b) is disposed between a second layer of polymer film (1412b; 1512b; 1612b) and a second layer of paper (1416b; 1516b) in a coating and contact relationship. 8. Construction according to claim 7, further comprising a third layer of paper (1424a; 1524a) attached to the second side of the base (1418; 1518a) in a substantially flat configuration through the corrugations (1422a; 1522a ; 1622a), thereby defining a series of insulating voids (1420a; 1520a) between the third layer of paper and the second side of the base. 9. Construction according to claim 7, wherein the first layer of paper (1416a; 1516a) is attached to the first side of the base (1418; 1518a) in a substantially flat configuration through the corrugations (1422a; 1522a) , thereby defining a series of insulating voids (1420a; 1520a) between the first layer of paper and the first side of the base. Construction according to any one of claims 1 to 9, in which each of the first susceptor layer (1402a; 1502a) and the second susceptor layer (1402b; 1502b) comprise a layer of material interactive with microwave energy which has a thickness between approximately 60 angstroms and approximately 100 angstroms. 11. Construction according to claim 10, wherein the microwave energy transparent zone (1404; 1504) of the central region (1408) and the microwave energy transparent zone (1406) of the peripheral region (1410) each comprise microwave-interactive material in a chemically deactivated state. 12. Construction according to any one of claims 1 to 11, wherein the first susceptor layer (1402a; 1502a) and the second susceptor layer (1402b; 1502b) are operative to convert at least part of the incident energy of microwaves in thermal energy. 13. Construction according to any of claims 1 to 12, wherein the microwave energy transparent zone (1404; 1504) of the central region (1408) and the microwave energy transparent zone (1406) The peripheral region (1410) are operative to allow microwave energy to pass through the respective susceptor layer.