Leak-Resistant Tray and Lid

This application is being filed on Aug. 19, 2020, as a PCT International Patent Application and claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/889,006, filed Aug. 19, 2019, entitled “Leak-Resistant Tray and Lid,” the disclosure of which is hereby incorporated by reference herein in its entirety.

Containers for the storage and transport of food include a tray and a lid, which may be separate or interconnected (e.g., clamshell). The tray and/or lid may be made from container materials including one or more of molded fiber or paperboard, plastic, or metal (e.g., aluminum). In some cases, an aluminum container is used in conjunction with a plastic lid, both components may be made of plastic, or molded fiber may be combined with plastics, and so on. Often, such containers merely contain the food for a limited time (sufficient to transport the food from a restaurant to home), but do not have sufficient structural integrity to prevent leaks. Leaks may occur due to failure of the material itself, a penetration of liquid between the tray and the lid, or a failure of a clean seal between the tray and lid due to manufacturing error and/or difficulties. This problem is especially apparent in containers that are made from organic (e.g., containing cellulose) materials such as molded fiber. Chemical and/or wax additives added to molded fiber to create the container material may improve the container material resistance to failure or penetration, but may limit the compostability or other desired features. Similarly, molded fiber manufacturing, due to its form (geometry) and aesthetic limitations, has typically been limited to the egg tray and industrial packaging markets.

In one aspect, the technology relates to a container having: a molded fiber tray having: a unitary fiber body defining at least one internal well, wherein the molded fiber body has a perimeter engaging wall extending upward from a perimeter rim of the molded fiber tray, the perimeter engaging wall has an inner surface, an outer surface, and an uppermost surface spanning the inner surface and the outer surface; and a molded fiber lid including: a unitary fiber body having at least one ceiling, and wherein the unitary fiber body defines a perimeter engaging receiver extending upward from a perimeter rim of the molded fiber lid, the perimeter engaging receiver at least partially defined by an inner wall, an outer wall, and an uppermost wall spanning the inner wall and the outer wall, wherein the perimeter engaging wall is configured to be removably received in the perimeter engaging receiver, wherein, when so received, the inner surface contacts the inner wall, the outer surface contacts the outer wall, and the uppermost surface contacts the uppermost wall, and wherein, when so received, the at least one internal well and the at least one ceiling define a substantially sealed internal volume. In an example, unitary fiber body of the molded fiber tray further includes at least one partition that subdivides the internal well into a plurality of wells, and wherein the unitary fiber body of the molded fiber lid defines at least one internal channel that subdivides the at least one ceiling into a plurality of ceilings, wherein the at least one internal channel is configured to mate with the at least one partition, and wherein, when so mated, each of the plurality of wells and plurality of ceilings define a discrete substantially sealed internal volume. In another example, the perimeter rim of the molded fiber tray is disposed substantially orthogonal to the outer surface and the inner surface. In yet another example, the perimeter rim of the molded finer tray has an outer rim disposed adjacent the outer wall and an inner rim disposed adjacent the inner wall, and wherein the inner rim is adjacent the at least one well. In still another example, the perimeter rim of the molded fiber lid is disposed substantially orthogonal to the outer wall and the inner wall.

In another example of the above aspect, the perimeter rim of the molded fiber lid has an outer rim disposed adjacent the outer surface and an inner rim disposed adjacent the inner surface, and wherein the molded fiber lid further includes at least one soffit disposed between the inner rim and the at least one ceiling. In an example, the molded fiber lid further includes at least one tab extending from the perimeter rim. In another example, the at least one partition has a major partition extending from a first side of the molded fiber tray to a second side of the molded fiber tray. In yet another example, the at least one partition further includes a minor partition extending from a third side of the molded fiber tray to the major partition. In still another example, the uppermost surface of the perimeter engaging wall at least partially defines a groove. In another example, the groove is continuous. In another example, the at least one partition at least partially defines a groove.

In another aspect, the technology relates to a container having: a molded fiber tray having: a unitary fiber body defining at least two internal wells, separated by a partition having a first well surface, a second well surface, and a partition uppermost surface spanning the first well surface and the second well surface, wherein the molded fiber body has a perimeter engaging wall extending upward from a perimeter rim of the molded fiber tray and at least partially surrounding both of the two internal wells, the perimeter engaging wall having an inner surface, an outer surface, and an uppermost surface spanning the inner surface and the outer surface, wherein the perimeter engaging wall uppermost surface at least partially defines a groove therein, and wherein the perimeter engaging wall uppermost surface is disposed at an elevation different than an elevation of the partition uppermost surface; and a molded fiber lid having: a unitary fiber body including at least one ceiling, a soffit extending from the at least one ceiling and defining an internal recess, a perimeter engaging receiver extending upward from a perimeter rim of the molded fiber lid, the perimeter engaging receiver at least partially defined by an inner wall, an outer wall, and an uppermost wall spanning the inner wall and the outer wall, wherein the partition is configured to be removably received in the internal recess, wherein, when so received, the soffit contacts at least one of the first well wall and the second well wall, wherein the perimeter engaging wall is configured to be removably received in the perimeter engaging receiver, wherein, when so received, the inner surface contacts the inner wall, the outer surface contacts the outer wall, and the uppermost surface contacts the uppermost wall, and wherein, when so received, the at least one internal well and the at least one ceiling define a substantially sealed internal volume.

Containers described herein include a tray portion made of molded fiber and a mating lid portion made of molded fiber. Specific materials, as well as methods of making such trays and lids, are also described. In general, the trays and lids described are connected at an interface portion, typically around an entire perimeter of the tray and lib, though other interior interface portions may be present in certain examples as depicted herein. The interface portion includes a wall formed on the tray that is received in a receiver defined by the lid. In other examples, the receiver may be defined by the tray, while the wall may project from a bottom of the lid. Additional surfaces adjacent this wall and receiver structure further seal the container when closed. These additional surfaces (along with the surfaces of the wall and receiver) include a number of surfaces disposed at various angles to each other. These various surfaces are connected to adjacent surfaces at curved transition surfaces. It has been determined that curved transition surfaces are more structurally sound and resist deformation better than sharp transition surfaces. The interface portion of the lid includes surfaces (again disposed at angles to each other) and curved transition surfaces. The interface portion of the lid is formed in a profile that matches, or substantially matches, the profile of the interface portion of the tray. Thus, when the interface portion of the tray and lid are engaged, these mating angled and curved surfaces form a reinforced structure that resists deformation due to forces that may be applied at any angle to the interface portion (e.g., during transport, if the container is dropped, or when the lid is pressed onto the tray).

The contacting surfaces of the tray and lid define a convoluted path that resists leakage of liquid therebetween, e.g., due to increased pressure of the fluid therein. For example, if the filled, closed container is being acted upon by a vertical downward force (e.g., if it is packed in the bottom of a full carrying bag), the liquid inside must travel a convoluted path to escape the container. This convoluted path is defined by the mating surfaces of the tray and lid. The change in orientation of the various surfaces along the potential fluid path are formed by the various angled surfaces, thus reinforcing the interface. This requires significantly higher internal liquid pressure for leakage to occur.

Containers may be formed to include one or more internal wells for food. Wells are separated by internal partitions formed in the body of the tray. The lid includes a corresponding number and configuration of channels that mate with the upper portions of the partitions. This mating between the partitions and channels prevents leakage between the various internal wells (referred to herein as “cross-contamination”). Further, since the partitions are formed by the body of the tray itself, adjacent wells are not disposed on opposite sides of a single, thin portion of material. Rather, each well has a dedicated wall and adjacent walls are separated by ambient air. This allows hot and cold foods to be placed in different wells of the same container, without heat transfer there between due to conduction or cross-contamination of contents.

Materials that may be used in the manufacture of the molded fiber tray and lid include those described in U.S. Pat. No. 10,036,126, entitled “Methods for Manufacturing Fiber-Based Beverage Lids,” the disclosure of which is hereby incorporated by reference herein in its entirety. These materials include, generally, a mixture of hardwood and softwood fibers, along with trace amounts of other additives, such as a strengthener, grease repellant, and water repellant. Contacting surfaces of the tray and lid may be both smooth, both rough, or one may be smooth and one may be rough. Roughness of the surface may be obtained by incorporating a mesh screen into the mold utilized for formation of the tray and/or lid. Alternatively, a surface may be roughened after manufacture of the tray or lid, for example, by mechanical processes.

are various views of a molded fiber tray. The features described with regard to the trayare primarily in reference to annotated, an upper perspective view of the molded fiber tray.depict other views of the tray: bottom perspective, top, bottom, front, back, right side, left side.are provided for further clarity and context, although not every feature is identified by number in every figure. Regardless, further construction details of the traywould be apparent to a person of skill in the art upon reading the following description.

The trayis formed as a unitary molded fiber body, having features, contours, and surfaces, as described herein. The bodyforms one or more wells (identified inas W, W, and W). Well Wis separated from well Wand well Wby a major partition. As used herein, the term “major partition” describes an internal partition between adjacent wells that terminates at a side (that is, a front side, a back side, a right side, and a left side) of the trayitself. Well Wand well Ware separated by a minor partition. As used herein, the term “minor partition” describes an internal partition between adjacent wells that terminates at a side (e.g., front, back, right, left) and another partition (e.g., major partition). Freestanding partitions (e.g., partitions that project upward from a bottom of the trayor that contact a single side or other partition) may also be utilized, for example, to disrupt fluid flow within the container to reduce or eliminate “sloshing” of liquids therein. The major partitionand minor partitionform some of the inner surfacesof the various wells and include an uppermost surfacethat spans the inner surfacesof adjacent wells. In the depicted example, the uppermost surfaceof the majorand minor partitionsare level with a tray perimeter inner rim. The floorof each well W, W, Wmay be flat across the entire expanse thereof, or may include one or more stepstherein, which can define further structural integrity. Stepsmay also be used to define a logo or other decorative feature into the tray. Structures having a plurality of steps may form a freestanding partition.

The tray perimeter inner rimis adjacent to a perimeter engaging wall (PEW). This PEWis a part of the sealing interface formed by engagement of the trayand lid. The PEWincludes an inner surfaceand an outer surface. Further details of the inner surfaceand outer surfaceare provided below. The inner surfaceprojects substantially upward from the perimeter inner rim, while the outer surfaceprojects substantially upward from a perimeter outer rim. The perimeter outer rimprojects from the side of the trayand acts to help seat the lid on the tray, as described below. The PEWalso includes an uppermost surfacethat spans the inner surfaceand outer surface. The uppermost surfacemay define therein a continuous groovethat extends the extent of the uppermost surface. In other examples, the groovemay be intermittent or partial along one or more portions of the uppermost surface. The grooveenables the PEWto resist deformation that may commonly occur when the lid is being engaged with the tray. The grooveis depicted as substantially curved in cross-sectional profile shape, but may be V-shaped. In another example, a profile of the curvemay define a semi-circle or a smaller portion of a circle. In examples, a groovemay also be formed in the uppermost surface of a major or minor partition, as depicted and described elsewhere herein.

In general, the depicted trayis a four-sided element defined a major axis and a minor axis. Opposing sides are parallel to a single axis. For example, sidesandare parallel to the minor axis, while sidesandare parallel to the major axis. Further, while the term “sides” is used to describe the outer lateral limits of the tray, the sides may further be defined by their location relative to a predetermined point of view. For example, the terms “front,” “back,” “right,” and “left,” may also be used to describe certain of the sides, in this case, the sides parallel to one of the axes. Thus, location of a particular well, for example, may be described based on the side(s) to which they are adjacent. Well W, for example, is located adjacent the front, left, and backsides of the tray, while well Wis located adjacent the backand rightsides and is further bounded by the majorand minorpartitions. The major and minor axes may also be used to describe the orientation of the various partitions, which may be straight, curved, at non-orthogonal angles to both the major and minor axes, etc. While the depicted trayincludes four sides, trays having other configurations of sides, such as five, six, or eight, are also contemplated. Trays having an equal number of sides are most likely to be utilized commercially. The terms “top”and “bottom”are used to describe, respectively, the upper and lower limits of the tray.

As noted, the tray bodyis formed from a unitary piece of molded material, having a material thickness generally consistent along its entire exposed area, within manufacturing tolerances. In examples, the material may be molded to a material thickness of about 1.0 mm to about 1.3 mm. In examples, 1.15 mm has shown particularly desirable results and performance. Material thickness may be further modified based on the material (e.g., food) being held in the tray; that is, lighter food having a lower moisture content (e.g., popcorn) may not require as thick of a material as heavier food having a higher moisture content (e.g., stew). Thus, material thicknesses of about 0.8 mm to about 1.5 mm and about 0.6 mm to about 1.7 mm are also contemplated. The materials utilized in the manufacture of the traymay be molded fiber, such as described in U.S. Pat. No. 10,036,126, entitled “Methods for Manufacturing Fiber-Based Beverage Lids,” the disclosure of which is hereby incorporated by reference herein in its entirety.

are various views of a molded fiber lid. The features described with regard to the lidare primarily in reference to annotated, a bottom perspective view of the molded fiber lid.depict other views of the lid: top perspective, top, bottom, front, back, right side, left side.are provided for further clarity and context, although not every feature is identified by number in every figure. Regardless, further construction details of the lidwould be apparent to a person of skill in the art upon reading the following description.

The lidis formed as a unitary molded fiber body, having features, contours, and surfaces, as described herein. The bodyforms one or more well ceilings (identified inas well ceiling C, well ceiling C, and well ceiling C). Well ceiling Cis separated from well ceiling Cand well ceiling Cby an internal channelthat corresponds to the major partitionof the tray. Well ceiling Cand well ceiling Care also separated by an internal channelthat corresponds to the minor partitionof the tray. Other channels may be present for any freestanding partitions and may support a ceiling of the tray, e.g., for a particularly wide well. The internal channels,include an internal channel uppermost surface, which contacts the partition uppermost surfacewhen the lidis engaged with the tray. Soffitsextend from the uppermost surfaceto each well ceiling C, C, C, thus locating the ceiling C, C, Cof any particular well W, W, Wbelow the uppermost surfaceof the partitions,. This help to seal each individual well W, W, Wfrom the others, thus preventing cross-contamination. In the depicted example, the uppermost surfaceof internal channels,are generally level with a lid perimeter inner rim.

The lid perimeter inner rimis adjacent to a perimeter engaging receiver (PER). This PERis a part of the sealing interface formed by engagement of the trayand lid. The PERis defined on the sides by an inner walland an outer wall. Further details of the inner walland outer wall(including their engagement with the inner surfaceand outer surfaceof the tray, respectively) are provided below. The inner wallprojects substantially upward from the perimeter inner rim, while the outer surfaceprojects substantially upward from a perimeter outer rim, which projects from the side of the lid. The PERis also defined by an uppermost wallthat spans the inner walland outer wall. A pull tabmay extend from the perimeter outer rim, e.g., at one or more corners, to ease removal of the lidfrom the tray. The lidalso has major and minor axes, as well as various sides,,,, as described above in the context of the tray(these are depicted in). The lidmay also be manufactured of the same material as the tray.

are partial sectional views of an example molded fiber trayand an example molded fiber lid.is a partial sectional view of a sealed molded fiber containerformed by the molded fiber trayand molded fiber lidof, respectively.describe primarily the components, surfaces, and other features that form the interface of the sealed container, along with other aspects of the design. Not all of the depicted features are necessarily described further or in additional detail. Specifically,depicts a sectional view through the back sideof the tray, at well W. Other sections around the various sides of the traywould be configured similarly.also depicts a standard Cartesian coordinate indicator having x and y axes. The components, surfaces, and other features described with regard tomay be measured relative to a Cartesian coordinate system as well known to persons of skill in the art. That is, a surface that is described as disposed an “a 30° angle to the x axis” would be understood to be disposed at an angle of 60° to the y axis. Further, the terms “horizontal” and “vertical” may also be used to describe surfaces oriented in the x axis only and y axis only, as understood in the art. Unless otherwise specified, angular orientations of components, surfaces, and features describe the orientation of surfaces of the traythat engage with surfaces of the lid, since that engagement is relevant to the function of the interface. As used herein, the term “transition” describes a part of the body,between two defined features of surface. One such transition T is depicted inbetween the tray perimeter inner rimand the PEW inner surface. Transitions T form a part of the component, feature, or surface to which it is adjacent. Thus, the depicted transition forms a part of the tray inner perimeter rimand the PEW inner surface. Thus, it will be understood that the tray perimeter inner rimis “adjacent” (as that term is used herein) to the PEW inner surface(even in the presence of the transition T) because that transition T forms a part of each of those elements for the purposes of this description. Angular orientation of a transition T, however, if not contemplated in the context of describing the angular orientation of an element of which it forms a part. Thus, assuming the depicted PEW inner surfaceis described as “vertical,” it does not include any horizontally-oriented parts, even though the transition T forms a part thereof. Not all transitions in the trayare labeled in, but will be apparent to a person of skill in the art.

The inner well surfaceis disposed at an angle to the y axis of about 5°, although angular ranges of about 0°, about 1°, about 2°, about 3°, about 4°, about 0° to about 10°, about 5° to about 15°, about 10° to about 20°, about 15° to about 25°, and about 20° to about 30° are also contemplated. Smaller angles are typically advantageous on walls that form a part of the majoror minorpartitions and may allow for improved sealing between adjacent wells, so as to prevent cross-contamination. The tray perimeter inner rimis disposed horizontally and is coextensive with the major partition uppermost surface(depicted in broken lines, for illustrative purposes). While the tray perimeter inner rimmay be disposed at an angle to the horizontal, a horizontal orientation aids in reinforcing the PEWas forces act vertically against the latter element. Thus, the tray perimeter inner rimis able to deflect in a vertical direction, thereby absorbing forces applied to the PEW. The PEW inner surfaceis vertical, as is the PEW outer surface; thus, the draft angle of the PEWis 0°. Other draft angles, from 0° up to and including each of 0.5°, 1.0°, 1.5°, 2.0°, and 2.5° are also contemplated. While even larger draft angles may be utilized, it has been determined that the above-referenced draft angles provide the most desired performance for all types of contained foods, that is those with high to low liquid contents. The PEW uppermost surfacedefines a groovethat aids in absorbing forces applied to the PEW, specifically those applied when the lidis forced onto the trayto seal it. The tray perimeter outer rimis horizontally disposed. A well outer surfaceis also depicted.

depicts a sectional view through the back sideof the lid, at well ceiling C. Other sections around the various sides,,of the lidwould be configured similarly.also depicts a standard Cartesian coordinate indicator having x and y axes; thus, the components, surfaces, and other features described with regard tomay be measured consistent with the descriptions provided above. Transitions T are also depicted, and are defined as described above. The well ceiling Cis horizontal. The soffitis disposed at an angle substantially similar or similar to that of the inner well surface. The lid perimeter inner rimis disposed horizontally so as to engage with the tray perimeter inner rim. The PER inner walland PER outer wallare angled so as to match the corresponding surfaces of the PEW (inner walland outer wall, respectively); thus, the draft angle of the PERis 0°. Other draft angles, from 0° up to and including each of 0.5°, 1.0°, 1.5°, 2.0°, and 2.5° are also contemplated. The PER uppermost surfacedefines the uppermost extent of the PER. The lid perimeter outer rimis horizontally disposed.

depicts the interface sectionof the containerthat includes the trayand lidof, respectively, the section views of both of which are depicted and may be read in conjunction therewith. Not all features of the trayand lidare depicted. The dimensions of a number of features are depicted. The distance Hfrom the uppermost surface of the partition to the ceiling Cof the lidis depicted. This distance may be about 5/16″, about ½″, or about ¾″. The height of the PEWmay be measured on either of the inner surface (at a height H) or the outer surface (at a height H). Either height may be about 5/16″, about ½″, or about ¾″. The width W of the PEWmay be a similar distance to the heights noted above. The combination of small draft angles of each of the partitions, the internal recesses, the PEW, and the PER, in combination with the distances described above, help seal the various wells against leakage between adjacent wells and external to the container. The distances described above form a long path that any liquid must be able to penetrate in order for leakage to occur.

also depicts the path that a liquid contained in the well would be required to follow to leak from the interface. A particular advantage of the depicted configuration is the number of sealing surfaces in the interface portion. Those sealing surfaces are numbered-, as counted from a hypothetical entry location of liquid to a hypothetical exit location. Sealing surfaceis located between the inner well surfaceand the soffit. Sealing surfaceis disposed between the tray perimeter inner rimand the lid perimeter inner rim. Sealing surfaceis between PEW inner surfaceand PER inner wall. Sealing surfaceis between a first portion of PEW uppermost surfaceand a first portion of PER uppermost wall. The groovedefines a small volume into which any liquid that may penetrate past sealing surfaces-may be contained, so as to limit leakage. Thus, the grooveacts as a liquid pressure relief, even if all of sealing surfaces-fail. Sealing surfaceis between a second portion of PEW uppermost surfaceand a second portion of PER uppermost wall. Sealing surfaceis between the PEW outer surfaceand the PER outer wall. Sealing surfaceis between the tray outer perimeter rimand the lid perimeter outer rim. In view of the above configuration, the hypothetical path of escape for a fluid via the interface is convoluted, with each transition T and adjacent portion of the interfaceresisting deflection that may enable leakage to occur.

is a partial view of a lockformed in the molded container. The lockmay be in the form of a projectionthat extends above a partition uppermost surfaceof the tray, which may help seal the containerin a location distal from the PEWand PER. The width of the projectionmay be substantially similar to that of a throatof a keeperformed on the lid(more specifically, the internal channel uppermost surface thereof). Use of the lockmay improve the sealing functionality between the trayand lidof the container.

is another example of a molded fiber tray. The features depicted inare generally similar to those depicted in, as such, the features are not specifically numbered or described, but would be apparent to a person of ordinary skill in the art, upon reading the above disclosure. One difference between the depicted trayand the tray depicted above is the inclusion of partition groovesdefined by the uppermost surfaceof both the major partitionand the minor partition. In other examples, the partition groovemay be disposed on only one partition,. The depicted grooveincludes both narrow portionsand wide portionsThe narrow portionsare disposed generally on the narrower width portions of the partitions,. The wide portionsare disposed proximate the intersection of the major partitionand minor partitionand near the ends of those features proximate the PEW. Thus, this inner grooveperforms much of the same functionality as the groovedisposed on the PEW.

depicts another example of a molded fiber lid. The features depicted inare generally similar to those depicted in, as such, the features are not specifically numbered or described, but would be apparent to a person of ordinary skill in the art, upon reading the above disclosure. The depicted lid, however, also includes a groovein the PER uppermost surface. This grooveis configured to mate with the groove defined by the PEW, e.g., as depicted in. These mating grooves may further improve the sealing capability between the PEW and the PER.

Any number of the features of the different examples described herein may be combined into one single example and alternate examples having fewer than or more than all of the features herein described are possible. It is to be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting. It must be noted that, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

While there have been described herein what are to be considered exemplary and preferred examples of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.