FIELD OF DISCLOSURE

[0001] The disclosed system and method relate to packaging. More specifically, the disclosed system and method relate to packaging for frozen foods that may be heated in a microwave oven.

BACKGROUND

[0002] With busy schedules, people seldom have time to prepare a home cooked meal from start to finish. Food companies have recognized that many families do not have to prepare a full meal and have attempted to fill this void by offering prepared foods that may be cooked in a microwave and yet still have a home-style taste. These foods are provided in special packaging that initially may be stored in a freezer and then heated in a microwave oven. Conventional food containers have been fabricated from polymer materials so that they may be heated in a microwave. However, these conventional materials tend to become brittle when stored in a freezer over a period of time, which leads to cracking of the microwavable container. Once the container is cracked, there is an increased likelihood of the contents of the container to leak from the container and causing a mess in the microwave oven or burning the person who retrieves the tray. Additionally, if the contents once heated to a high temperature in the microwave oven, the leaking food product may even cause a burn.

[0003] The foregoing has also led to an exponential growth of the use of polymeric materials leading to the accumulation of huge amounts of non-degradable waste materials across our planet. This growing threat to the environment has led to research in biodegradable and renewable materials as replacement for non-degradable, commonly used materials. Also, the production of polymers through utilization of renewable and sustainable resources has been a field of increasing interest for many years.

[0004] As a consequence, there has been a need in the art for a microwave-safe polymeric material, that is producible from sustainable raw material sources. SUMMARY

[0005] The present invention responds to the challenge of finding an environmentally sustainable microwavable food storage container that includes a body formed from material- filled polypropylene. The container includes a bottom wall and a plurality of sidewalls extending from the bottom wall to define a compartment. A plurality of structural elements are arranged on the bottom wall and on the plurality of sidewalls for increasing a strength of the microwavable food storage container.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:

[0007] FIG. 1 is a top side plan view of one example of an improved tray;

[0008] FIG. 2 is a cross-sectional view of the tray illustrated in FIG. 1 taken along line 2-

2 in FIG. 1;

[0009] FIG. 3 is a cross-sectional view of the tray illustrated in FIG. 1 taken along line 3-

3 in FIG. 1;

[0010] FIG. 4 is a sectional view of the tray illustrated in FIG. 1 taken along line 4-4 in

FIG. 1;

[0011] FIG. 5 is a side view of the tray illustrated in FIG. 1;

[0012] FIG. 6 is an end view of the tray illustrated in FIG. 1;

[0013] FIG. 7 is a sectional view of a pair of stacked trays in accordance with the tray illustrated in FIG. 1;

[0014] FIG. 8 is a top side plan view of another example of an improved tray in accordance with the present disclosure;

[0015] FIG. 9 is a cross-sectional view of the tray illustrated in FIG. 8 taken along line 9-

9 in FIG. 8;

[0016] FIG. 10 is a cross-sectional view of the tray illustrated in FIG. 8 taken along line

10-10 in FIG. 8;

[0017] FIG. 11 is a side view of the tray illustrated in FIG. 8; [0018] FIG.

[0019] FIG.

accordance with the

[0020] FIG.

14-14 in FIG. 13;

[0021] FIG.

[0022] FIG.

16-16 in FIG. 13;

[0023] FIG.

[0024] FIG.

accordance with the

[0025] FIG.

19-19 in FIG. 18;

[0026] FFIIGG.. 20 is a sectional view of the tray illustrated in FIG. 18 taken along line in FIG. 18;

[0027] FIG.

[0028] FIG.

[0029] FIG.

accordance with the

[0030] FIG.

24-24 in FIG. 23;

[0031] FIG.

[0032] FIG.

accordance with the

[0033] FIG.

27-27 in FIG. 26;

[0034] FIG.

28-28 in FIG. 26;

[0035] FIG.

[0036] FIG. DETAILED DESCRIPTION

[0037] This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. The drawing figures are not necessarily to scale and certain features of the disclosed system and method may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as "horizontal," "vertical," "up," "down," "top," and "bottom" as well as derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including "inwardly" versus "outwardly," "longitudinal" versus "lateral," and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling, and the like, such as "connected" and "interconnected," refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term "operatively connected" is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship.

[0038] FIGS. 1-7 illustrate one example of a tray 100 for storing frozen meals that may be heated in a microwave in accordance with the present disclosure. Tray 100 is preferably fabricated from a mineral-filled polypropylene material to increase the flexibility of tray 100 to prevent cracking when stored in the freezer. The arrangement aids in preventing the creation of "chips" when the material cracks, that may otherwise be ingested by the consumer. In some embodiments, the mineral filling the polypropylene is calcium carbonate that preferably comprises between approximately 30 percent and 50 percent of the overall weight of tray 100, more preferably between 35 percent and 45 of the overall weight, and even more preferably approximately 40 percent of the overall weight of tray 100.

[0039] As illustrated in FIGS. 1, 2, 5, and 6, tray 100 includes a substantially planar bottom wall 102 having a substantially rectangular geometry comprising first and second lengthwise sides 104 and 106 having a length in the range of approximately 20-26 centimeters, with a length of about 23 centimeters being preferred, and first and second widthwise sides 108 and 110 having widths of approximately 11 to 14 centimeters, with 12.7 centimeters being preferred. Although bottom wall 102 of tray 100 is illustrated as having a rectangular geometry, one skilled in the art will understand that bottom wall 102 of tray 100 may have other geometries including, but not limited to, circular, oval, pentagonal, and hexagonal, to name a few.

[0040] A pair of sidewalls 112 and 114 vertically extend from lengthwise sides 104 and

106, and a pair of sidewalls 116 and 118 vertically extend from widthwise sides 108 and 110 to define a food- storage compartment 120. In one embodiment, sidewalls 112-118 extend from bottom wall 102 at an angle of approximately 99° to 103° with respect to a plane defined by bottom wall 102, with about 101° being preferred, and to a height of approximately 3.5 centimeters. Additionally, each of the sidewalls 112-118 includes a flange 122 that outwardly extends from the sidewalls 112-118. Put another way, flange 122 extends away from food- storage compartment 120 defined by sidewalls 112-118. As best seen in FIG. 1, the corners 124, 126, 128, and 130 between adjacent sidewalls 112-118 may be rounded such that they have radii between approximately 2.5 and 5 centimeters (approximately one and two inches), and more particularly, between approximately between 3.2 centimeters (approximately 1.25 inches) and approximately 4.4 centimeters (approximately 1.75 inches).

[0041] The addition of one or more minerals such as, for example, calcium carbonate to the polypropylene from which tray 100 is fabricated advantageously increases the flexibility of tray 100 such that tray 100 does not become as brittle when stored in a freezer for a prolonged period of time. To improve the structural integrity of the more resilient tray 100, tray 100 is provided with a plurality of chevron-shaped ridges 132, 134, 136, and 138 being formed and extending from bottom wall 102 as well as a plurality of flutes 140 formed at the interface 142 between bottom wall 102 and sidewalls 112-118. As best seen in FIG. 1, ridges 132 and 134 each include a first and segments 144 and 146 disposed at angles relative to an axis defined by one of the widthwise extending sidewalls 116 and 118. In one embodiment, an angle between an axis defined by widthwise side 108 and segment 144 of ridge 132 is preferably between 20 and 70 degrees, more preferably between 30 and 60 degrees, and even more preferably between 40 and 50 degrees. Similarly an angle between the axis defined by widthwise side 108 and segment 146 of ridge 132 is preferably between 20 and 70 degrees, more preferably between 30 and 60 degrees, and even more preferably between 40 and 50 degrees. In one embodiment, segment 144 of ridge 132 is parallel to segment 144 of ridge 134 as well as any other segment 144 of a ridge disposed on the same side of a centerline that extends in a widthwise direction across tray 100 as ridge 132.

[0042] As shown in FIG. 1, chevron-shaped ridges 136 and 138 are disposed on an opposite side of the widthwise centerline on which ridges 132 and 134 are disposed and each includes a pair of segments 148 and 150. Segments 148 of ridges 136 and 138 are parallel to one another and each define an angle with an axis defined by widthwise sidewall 118 that is preferably between approximately 20 and 70 degrees, more preferably between 30 and 60 degrees, and even more preferably between 40 and 50 degrees. Similarly, segments 150 of ridges 136 and 138 are parallel to one another and each define an angle with an axis defined by widthwise sidewall 118 that is preferably between approximately 20 and 70 degrees, more preferably between 30 and 60 degrees, and even more preferably between 40 and 50 degrees.

[0043] Referring to FIGS. 1-3, bottom wall 102 also includes a corrugation 152 that extends around the periphery of bottom wall 102 such that corrugation 152 also has a rectangular shape or the shape of bottom wall 102. Corrugation 152 intersections each of ridges 132-138 at an intersection 154, which may have a triangular shape, as illustrated in FIG. 1.

[0044] Like ridges 132-138 and corrugation 152, flutes 140 inwardly project into compartment 120 and may be equally spaced apart from one another, although one skilled in the art will understand that flues 140 may be unequally disposed from one another. FIGS. 5 and 6 illustrate flutes 140 as extending from an apex 156 disposed adjacent to top 158 of sidewalls 112-118 to a rounded base 160 disposed adjacent to interface 142 between sidewalls 112-118 and bottom wall 102. Base 160 may have a width that is greater than a width of apex 156 such that flutes 140 may taper along their respective lengths from top to bottom.

[0045] Widthwise sidewalls 116 and 118, which are disposed at opposite ends of tray

100, include an inwardly projecting protuberances 162 that define handles in conjunction with outwardly extending flanges 122 as best seen in FIGS. 1 and 6. Referring now to FIGS. 3, 4, and 7, sidewalls 112-118 may also include an outwardly projecting ledge 164 disposed adjacent to outwardly extending flange 122. FIG. 7 illustrates first and second trays 100-1 and 100-2 (collectively referred to as "trays 100") stacked together and how ledges 164 advantageously assists in separating stacked trays 100 from one another. As shown in FIG. 7, ledge 164-1 is disposed in an abutting relationship with flange 122-2 such that a gap is defined between flanges 122-1 and 122-2. Accordingly, a person may use the gap created by ledge 164-1 to separate trays 100.

[0046] Fabricating tray 100 from mineral-filled polypropylene, such as polypropylene filled with approximately 40 percent by weight of calcium carbonate, advantageously increases the flexibility of tray 100 such that tray 100 is more resistant cracking when filled with food and disposed within a freezer for long periods of time. Additionally, the inclusion of structural members such as ridges 132-138, flutes 140, and corrugation 152 advantageously increases the structure integrity of the resultant tray 100 such that tray 100 may be used as a vessel for microwaving and eating foods heated in a microwave oven and disposed within compartment 120 with limited bending or folding of tray 100.

[0047] FIGS. 8-12 illustrate another example of an improved tray 200 fabricated from mineral-filled polypropylene. In FIGS. 8-10, tray 200 is illustrated as having a substantially planar bottom wall 202 comprising a pair of opposed lengthwise sides 204 and 206 and a pair of opposed widthwise sides 208 and 210 that define a rectangular geometry. Although bottom wall 202 of tray 200 is illustrated as having a rectangular geometry, one skilled in the art will understand that bottom wall 202 of tray 200 may have other geometries including, but not limited to, circular, oval, pentagonal, and hexagonal, to name a few.

[0048] A pair of lengthwise sidewalls 212 and 214 extend from sides 204 and 206 of bottom wall 202, and a pair of widthwise sidewalls 216 and 218 extend from sides 208 and 210 or bottom wall 202 to collectively define a food-storage compartment 220. In one embodiment, sidewalls 212-218 extend from bottom wall 202 at an angle of approximately 100 degrees with respect to a plane defined by bottom wall 202. However, one skilled in the art will understand that sidewalls 212-218 may extend from bottom wall 202 at other angles including, but not limited to, from angles greater than or equal to 90 degrees to angles approximately less than or equal to 140 degrees. Each of sidewalls 212-218 include a flange 222 that outwardly projects from their respective tops 244. As best seen in FIG. 8, the corners 224, 226, 228, and 230 between adjacent sidewalls 212-218 may be rounded.

[0049] Tray 200 also includes a curved ridge 232 extending in a widthwise direction across tray 200. Ridge 232 divides compartment 220 into two separate and distinct

compartments 220-1 and 220-2 as best seen in FIGS. 8 and 9. In addition to providing separate compartments 220-1 and 220-2 for storing separate foods, ridge 232 advantageously increases the rigidity and structural integrity of tray 200 and may include a plurality of alternately winding segments 234, 236, and 238. Although ridge 232 is illustrated as extending across tray 200 in a widthwise direction, one skilled in the art will understand that ridge 232 may extend diagonally across tray 200 or extend in a lengthwise direction across tray 200.

[0050] Sidewalls 212-218 also include a plurality of spaced apart flutes 240 that extend from an interface 142 between bottom wall 202 and sidewalls 212-218 to a top 244 of sidewalls 212-218 for further increasing the stability of tray 200. Flutes 240 inwardly project into compartments 220-1 and 220-2 (collectively referred to as "compartments 220") and may be equally spaced from one another. Base 246 of flutes 240 may be rounded and taper to an apex 248 having a smaller width than the width of base 246 as best seen in FIGS. 11 and 12.

Although flutes 240 are not shown as being disposed along ridge 232, one skilled in the art will understand that ridge 232 may also include flutes 240. Referring to FIG. 10, an outwardly projecting ledge 250 is illustrated as being disposed adjacent to outwardly extending flanges 222 on sidewalls 212-218 for aiding in the separation stacked trays 200.

[0051] As best seen in FIGS. 8 and 9, each of the compartments 220 includes a respective corrugation 252-1 and 252-2 (collectively referred to as "corrugations 252") that inwardly extends from bottom wall 202 around the periphery of the compartments 220. In some embodiments, corrugations 252 substantially parallel the boundaries of the respective compartment in which the corrugations 252 are formed as shown in FIGS. 8 and 9. However, in some embodiments, corrugations 252 may not be substantially parallel the boundaries of the respective compartments in which the corrugations 252 are formed.

[0052] Turning now to FIGS. 8 and 12, widthwise sidewalls 216 and 218 may each include an inwardly projecting protuberance 254 that extends into compartment 220.

Protuberances 254 cooperate with flanges 222 to provide a handle for tray 200. As best seen in FIG. 12, protuberances 254 may be wider adjacent to the top 244 of sidewalls 216 and 218 and narrower adjacent to bottom wall 202. The sides 256 of protuberances have a curved shape, although in some embodiments sides 256 of protuberances 254 may be substantially straight and parallel to one another such that protuberances 254 have a substantially rectangular shape.

[0053] Fabricating tray 200 from mineral-filled polypropylene, such as polypropylene filled with approximately 40 percent by weight of calcium carbonate, advantageously increases the flexibility of tray 200 such that tray 200 is more resistant cracking when filled with food and disposed within a freezer for long periods of time. Additionally, the inclusion of structural members such as curved ridge 232, flutes 240, and corrugations 252 advantageously increases the structure integrity of the resultant tray 200 such that tray 200 may be used as a vessel for micro waving and eating foods disposed within compartment 120 after having been heated in a microwave with limited bending or folding of tray 200.

[0054] FIGS. 13-17 illustrate another example of an improved tray 300 fabricated from a mineral- filled polypropylene. As shown in FIGS. 13-17, tray 300 includes a substantially planar bottom wall 302 having a pair of substantially parallel opposed widthwise sides 304 and 306 and a pair of outwardly bowed lengthwise sides 308 and 310. Extending from widthwise ends 304 and 306 are widthwise sidewalls 312 and 314, and sidewalls 316 and 318 extend from lengthwise sides 308 and 310 to collectively define an internal compartment 320. Sidewalls 312-318 include an outwardly extending flange 322 and intersect one another at rounded corners 324, 326, 328, and 330.

[0055] A continuous ridge or step 332 is formed at an abrupt transition between an upper portion 334 and a lower portion 336 of sidewalls 312-318. As best seen in FIGS. 15 and 16, for example, a distance between upper portions 334 of sidewalls 312 and 314 is greater than a distance between lower portions 336 of sidewalls 312 and 314 such that a step defining the ridge 332 is formed at the transition between the upper and lower portions 334 and 336. In some embodiments, ridge 332 curves along sidewalls 312-318 such that a distance between flange 322 and ridge 332 at some positions along sidewalls 312-318 is greater than a distance between flange 322 and ridge 332 at other positions. For example and as best seen in FIGS. 14 and 15, a distance between flange 322 and ridge 332 at an approximate midway point along widthwise sidewalls 314 is greater than a distance between flange 322 and ridge 332 at a position adjacent to corner 330.

[0056] Sidewalls 312-318 may also include a second curved ridge 338 disposed adjacent to the interface 340 between bottom wall 302 and sidewalls 312-318. As illustrated in FIG. 15, ridge 338 curves along sidewalls 312-318 such that a distance between bottom wall 302 and ridge 338 is greater at an approximate midway point along widthwise sidewalls 312 and 314 than at positions closer to corners 328 and 330.

[0057] Tray 300, like trays 100 and 200 described above, may be fabricated from polypropylene filled with calcium carbonate through a molding process. The calcium carbonate preferably comprises between 30 and 50 percent of the weight of tray 300, more preferably between 35 and 45 percent of tray 300 by weight, and most preferably approximately 40 percent of tray 300 by weight. The structural members such as, for example, ridges 332 and 338 advantageously enable the flexible material to have sufficient structural integrity to support foods heated in microwave ovens.

[0058] FIGS. 18-22 illustrate another example of an improved tray 400 fabricated from polypropylene that may be filled with approximately 40 percent by weight of calcium carbonate. Tray 400 is similar to tray 300 described above and descriptions of like elements, which include the same reference numerals increased by 100, are not repeated.

[0059] As shown in FIGS. 18-22, tray 400 includes an inwardly projecting ridge 442 extending from bottom wall 402 such that ridge 442 divides compartment 420 into two separate compartments 420-1 and 420-2. Ridge 442 is illustrated as having a bowed shape such that a concave surface 444 points towards compartment 420-2 and a convex surface 446 points towards compartment 420-1. The intersections 448 between ridge 442 and sidewalls 412 and 414 may have a triangular shape as a width of ridge 442 increases closer to sidewalls 412 and 414.

[0060] FIGS. 23-25 illustrate another example of a material-filled polypropylene tray 500 for storing frozen meals that may be heated in a microwave. Specifically, tray 500 is similar to tray 300 described above except that tray 500 has a substantially square geometry. Like reference numerals in FIGS. 23-25 that have been increased by 200 denote like features in FIGS. 13-17, which have been described above, and repetitive descriptions are not provided.

[0061] FIGS. 26-30 illustrate another example of a material-filled polypropylene tray 600 for storing frozen meals that may be heated in a microwave. Tray 600 is similar to tray 400 described above except that tray 600 has a substantially square geometry whereas tray 400 is illustrated as having a rectangular geometry. Like reference numerals in FIGS. 26-30 that have been increased by 200 denote like features in FIGS. 18-22, which have been described above, and repetitive descriptions are not provided. As shown in FIG. 26, ridge 642 of tray 600 has a slightly curved shape and does not have a bowed shape like ridge 442 of tray 400 illustrated in FIG. 18.

[0062] As described above, each of the trays described herein may be fabricated from mineral-filled polypropylene that advantageously increases the flexibility of the tray thereby reducing the likelihood of the tray cracking when stored in a freezer for an extended period of time. In one embodiment, the polypropylene is preferably filled with calcium carbonate in which the calcium carbonate comprises between approximately 30 percent and 50 percent of the overall weight of tray 100, more preferably between 35 percent and 45 of the overall weight, and even more preferably approximately 40 percent of the overall weight of tray. Various structural elements such as, for example, ridges, flutes, and corrugations are provided to enhance the structural integrity of the tray enabling the tray to support various food products even after the tray and food products disposed therein have been heated in a microwave oven.

[0063] Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.