A leak-resistant hinged polymeric foam container comprises a base and a lid. The base comprises a bottom wall and a sidewall that encompasses and extends generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base. The container forms a locking structure for securing the lid and the base. The base and the lid comprise polymeric foams. The container may include a hinge that hingedly connects the base to the lid.

FIELD OF THE INVENTION

The present invention relates generally to containers. More particularly, the invention relates to polymeric foam containers such as hinged-lid containers with improved leak resistance.

BACKGROUND OF THE INVENTION

Many types of foam containers have been used in the past for a variety of purposes. One type of these polymeric containers is a foam container that includes a base and a hinged lid. One of the most common uses for such containers is for holding food, either to package food when purchased or for holding leftovers from a purchased meal. One advantage of these containers is their insulative properties that keep food hot or cold in the containers until the food can be properly stored.

These containers, however, have the disadvantage of liquids leaking from the container. Leakage may occur at many locations from the container. For example, the liquid may leak at the location of a hinge and/or at a slot in the container used to lock the lid and the base. The hinge of these containers typically interrupts a seal formed between lid and the base, while the slot is an opening in the base of the container. Leakage may also occur around the rims of these containers where an incomplete seal exists between the lid and base. The leakage is often most pronounced when the container is tilted at extreme angles relative to a general horizontal position. It would be desirable to provide a foam container that can be handled that prevents or inhibits liquid from leaking therefrom.

SUMMARY OF THE INVENTION

According to one embodiment, a leak-resistant hinged polymeric foam container comprises a base, a hinge and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The first sealing area includes a first generally outwardly projecting ledge, a second generally outwardly projecting ledge, and a second generally upwardly projecting wall. The second generally upwardly projecting wall encompasses and extends generally upwardly from the second generally outwardly projecting ledge. The first generally outwardly projecting ledge encompasses and extends generally outwardly from the second generally upwardly projecting wall. The first generally upwardly projecting wall encompasses and extends generally upwardly from the first generally outwardly projecting ledge.

The hinge is connected to the base. The lid is hingedly connected to the base by the hinge. The lid is adapted to be pivoted about the hinge to engage the base upon closure of the container. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base. The container forms locking means for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam. One example of locking means is at least one undercut. According to one method, this container may be made by providing a foamable resin in an extruder. The foamable resin is melted in the extruder and then the foamable resin is extruded from the extruder to form an extruded material. The extruded material is thermoformed into the container.

According to another embodiment, a leak-resistant polymeric foam container comprises a base and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The first sealing area includes a first generally outwardly projecting ledge, a second generally outwardly projecting ledge, and a second generally upwardly projecting wall. The second generally upwardly projecting wall encompasses and extends generally upwardly from the second generally outwardly projecting ledge. The first generally outwardly projecting ledge encompasses and extends generally outwardly from the second generally upwardly projecting wall. The first generally upwardly projecting wall encompasses and extends generally upwardly from the first generally outwardly projecting ledge.

The lid is configured to mate with the base to form a closed position. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base to form the closed position. The container forms locking means for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam. One example of locking means is at least one undercut.

According to a further embodiment, a leak-resistant hinged polymeric foam container comprises a base, a hinge and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The hinge is connected to the base. The hinge, when in a closed position, comprises a first generally horizontal portion, a second generally horizontal portion, and a first generally vertical portion that are integrally connected to each other. The second generally horizontal portion is folded over the first generally horizontal portion. The first generally vertical portion extends generally downwardly from the second generally horizontal portion towards the bottom wall. The lid is hingedly connected to the base by the hinge. The lid is adapted to be pivoted about the hinge to engage the base upon closure of the container. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base. The container forms locking means for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam. One example of locking means is at least one undercut.

According to yet another embodiment, a leak-resistant hinged polymeric foam container comprises a base, a hinge and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The first sealing area includes a first generally outwardly projecting ledge, a second generally outwardly projecting ledge, and a second generally upwardly projecting wall. The second generally upwardly projecting wall encompasses and extends generally upwardly from the second generally outwardly projecting ledge. The first generally outwardly projecting ledge encompasses and extends generally outwardly from the second generally upwardly projecting wall. The first generally upwardly projecting wall encompasses and extends generally upwardly from the first generally outwardly projecting ledge.

The hinge is connected to the base. The lid is hingedly connected to the base by the hinge. The lid is adapted to be pivoted about the hinge to engage the base upon closure of the container. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base. One of the first sealing area and the second sealing area forms a projection and the other one of the first sealing area and the second sealing area forms a corresponding recess for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam.

According to yet a further embodiment, a leak-resistant polymeric foam container comprises a base and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The first sealing area includes a first generally outwardly projecting ledge, a second generally outwardly projecting ledge, and a second generally upwardly projecting wall. The second generally upwardly projecting wall encompasses and extends generally upwardly from the second generally outwardly projecting ledge. The first generally outwardly projecting ledge encompasses and extends generally outwardly from the second generally upwardly projecting wall. The first generally upwardly projecting wall encompasses and extends generally upwardly from the first generally outwardly projecting ledge.

The lid is configured to mate with the base to form a closed position. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base to form the closed position. One of the first sealing area and the second sealing area forms a projection and the other one of the first sealing area and the second sealing area forms a corresponding recess for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam.

According to another embodiment, a leak-resistant hinged polymeric foam container comprises a base, a hinge and a lid. The base comprises a bottom wall and a sidewall encompassing and extending generally upwardly from the bottom wall. The sidewall comprises a first sealing area and a first generally upwardly projecting wall. The hinge is connected to the base. The hinge, when in a closed position, comprises a first generally horizontal portion, a second generally horizontal portion, and a first generally vertical portion that are integrally connected to each other. The second generally horizontal portion is folded over the first generally horizontal portion. The first generally vertical portion extends generally downwardly from the second generally horizontal portion towards the bottom wall. The lid is hingedly connected to the base by the hinge. The lid is adapted to be pivoted about the hinge to engage the base upon closure of the container. The lid includes a second sealing area that is adapted to engage the first sealing area upon securing the lid and the base. One of the first sealing area and the second sealing area forms a projection and the other one of the first sealing area and the second sealing area forms a corresponding recess for securing the lid and the base. The base comprises a polymeric foam and the lid comprises a polymeric foam.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Referring now toFIGS. 1–3,4aand5, there is illustrated a leak-resistant polymeric foam container10according to one embodiment of the present invention. The foam container10includes a base12and a lid14. The lid14is connected to the base12by a hinge16allowing the lid14to be pivoted about the hinge16between a container open position (FIG. 1) and a container closed position (FIG. 2). The hinge16is shown as being integral with the base12and the lid14inFIGS. 1 and 2. Other embodiments of the present invention are shown inFIGS. 6 and 7, andFIG. 8with polymeric foam containers100and200, respectively.

According to other embodiments, leak-resistant polymeric foam containers comprise a base and a lid such as shown inFIGS. 1,6and8, but without a hinge. In other words, the containers are formed using separate and distinct bases and lids.

The base12includes a bottom wall18and a sidewall20that encompasses and extends generally upwardly therefrom. As shown inFIG. 3, the bottom wall18includes a recessed portion22with an upper surface22athat extends above a remainder24of the bottom wall18. The upper surface22aof the recessed portion22functions to hold food above the remainder24of the bottom wall18and away from liquids that collect in the remainder24of the bottom wall18. In addition, when several containers10are stacked on each other, a raised portion26on the lid14of one container corresponds to or fits into the underside of the recessed portion22formed in a base12of another container. This fit tends to prevent or inhibit stacked containers from sliding relative to each other and, thus, assists in stacking a plurality of containers. It is contemplated that the upper surface of the container may include a recessed portion that is adapted to fit in a raised portion of a base of another container.

Referring back toFIG. 1, to assist in providing leak-resistance to the container10of the present invention, the sidewall20of the base12forms a first sealing area40. The first sealing area includes a first generally outwardly projecting ledge44, a second generally outwardly projecting ledge42, and a second generally upwardly projecting wall46. More specifically, the first generally outwardly projecting ledge44is a generally horizontal ledge, the second generally outwardly projecting ledge42is a generally horizontal ledge, and the second generally upwardly projecting wall46is a generally vertical wall. It is contemplated that the ledges42and46may be substantially horizontal and the wall46may be substantially vertical.

The sidewall20of the container10also includes a first generally upwardly projecting wall48. More specifically, the first generally upwardly projecting wall48is a generally vertical wall. The second generally upwardly projecting wall46encompasses and extends generally upwardly from the second generally outwardly projecting ledge42. The first generally outwardly projecting ledge44encompasses and extends outwardly from the second upwardly projecting wall46. The first generally upwardly projecting wall48encompasses and extends generally upwardly from the first generally outwardly projecting ledge44.

The first sealing area40of the base12as shown inFIGS. 1 and 5is an uninterrupted or continuous surface that extends around the entire periphery of the base12. The first sealing area is preferably an uninterrupted or continuous surface so as to assist in preventing or inhibiting leakage from the container. To allow an uninterrupted seal to be formed upon closure of the lid14on the base12, the first sealing area40ofFIG. 1is spaced from the hinge16. It is contemplated that the container may have a first sealing area formed by less than three surfaces of the base. For example, the container may have one or two surfaces of the lid that forms the first sealing area. It is contemplated that the first sealing area may be formed by two non-contiguous surfaces. For example, the sealing area may be two generally horizontal surfaces or two generally vertical surfaces that are spaced apart from reach other. It is contemplated that the sealing surfaces may be discontinuous around the periphery of the base.

Referring to FIGS.1and3–4a, the first generally upwardly projecting wall48of the base12forms a plurality of undercuts50therein. The plurality of undercuts assists in forming a leak-resistant container when they extend over a second sealing area of the lid14upon closure of the container to lock the lid onto the base. The plurality of undercuts assists in maintaining the lid and the base in a closed position. The plurality of undercuts desirably forms a generally consistent downward pressure across the outer circumference of the lid14. The plurality of undercuts50is, in simplest terms, pushed-in sections of the first generally upwardly projecting wall48that do not form an opening therein that could lead to liquid leakage. The use of a plurality of undercuts is desirable because they form an improved seal as compared to slots or cut-outs in combination with tab closures because of the elimination of holes.

It is also contemplated that the base12may form at least one undercut therein. One method of forming the plurality of undercuts50is described in U.S. Pat. No. 6,261,504 B1. It is contemplated that the at least one undercut may be formed by other methods.

Alternatively, the first generally upwardly projecting wall48of the base may form slots or cut-outs that are used with tab closures to assist in locking the lid into the base. It is also contemplated that the lid may remain closed or locked to the base by using one continuous undercut ring. The continuous undercut ring, according to one embodiment, would extend substantially around the inner surface of a generally upwardly projecting wall such as, for example, the first generally upwardly projecting wall48ofFIG. 1. It is contemplated that the undercut ring may be discontinuous by only extending partially around the first generally upwardly projecting wall. It is also contemplated that two or more of the at least one undercut, slot and tab closures, a continuous undercut ring, and a discontinuous undercut ring may be combined together to form the sealing area.

Referring back toFIGS. 1,2and5, the base12further includes a tab extension52to assist in opening the container from a closed position. The tab extension52also assists in closing the container from an open position. The tab extension52encompasses and extends outwardly from the first generally upwardly projecting wall48of the base12. The tab extension52is shown inFIGS. 1,2and5as being generally circular or oval in shape. It is contemplated that the tab extension, if used, may be shaped differently such as, for example, rectangular, square or other polygonal shapes. It is desirable for the tab extension52to be located generally opposite of the hinge to better assist a user in opening the container from a closed position. It is contemplated, however, that the tab extension may be located in a different position than depicted, for example, inFIG. 2. It is also contemplated that more than one tab extension may be formed in the container.

The base12is intended to hold objects such as food and may include optional divider walls of any configuration desired for its intended use. The optional divider walls define separate compartments in the base. Different food may be placed in the separate compartments with the divider walls to prevent or inhibit mixing of the different food and their juices. To provide improved stability to the container, the divider walls of the base may flare at their respective ends to define a flat surface.

One example of such a container with divider walls is depicted inFIG. 8. The container200ofFIG. 8includes a base212and a plurality of divider walls230that includes a first divider wall230aand a second divider wall230b. The first divider wall230aextends across a sidewall220of the base212and the second divider wall230bextends from the first divider wall230ato one portion of the sidewall220. The divider walls230a,bwill typically not extend upwardly to a generally outwardly projecting ledge242of the sidewall220because of the potential to interfere with sealing area240.

The sidewalls of the containers may include features such as ribs. For example, as shown inFIG. 6, the container100includes a sidewall120that forms a plurality of ribs132. The number of ribs, if any, on the sidewall may vary from that shown in the container100ofFIG. 6. The container100ofFIG. 6includes nine ribs that are spaced generally equidistance from each other. The portion of the sidewall120with the plurality of ribs132is shaped in a scalloped manner (i.e., a plurality of distinct outwardly concave projections as viewed from an interior of the base).

The hinge16is shown inFIGS. 1–3as being integral with a portion of the lid14and a portion of the base12. The lid14is hingedly connected to the base12by the hinge16such that the lid14is adapted to be pivoted about the hinge16to engage the base12upon closure of the container10. The hinged area in at least some prior art hinged-containers tended to produce undesirable leakage. To assist in preventing or inhibiting leakage, the configuration of the hinge16allows the hinged area to complete the seal of the lid14to the base12. The hinge16preferably does not interrupt the first sealing area40of the base12or the second sealing area70of the lid14.

As shown inFIG. 2, the hinge16comprises a first hinge portion16a, a second hinge portion16b, and a third hinge portion16c, which are integrally connected with each other. The hinge16is formed to allow sufficient movement or “play” to close the container. This sufficient movement assists in easier closure of the base and lid by the user. In the locked position of the base and lid, the third hinge portion16cextends generally downward from about an upper edge of the projecting wall48. The third hinge portion generally extends downwardly from about ¼ to about ¾ of an inch from the upper edge of the projecting wall48.

The lid14ofFIGS. 2 and 3includes a top surface66and a peripheral sidewall68that encompasses and extending therearound. The top surface66of the lid14includes a raised portion26that allows stacking of the containers10. It is also contemplated that the raised portion may be instead recessed so as to allow stacking of the containers.

To assist in providing leak-resistance to the container10of the present invention, the lid14further includes a second sealing area70. The second sealing area70encompasses and extends generally outwardly from the peripheral sidewall68. The second sealing area70includes a first generally outwardly projecting surface76, a second generally outwardly projecting surface72, and a first generally upwardly projecting wall74. More specifically, the first generally outwardly projecting surface76is a generally horizontal surface, the second generally outwardly projecting surface72is a generally horizontal surface, and the first generally upwardly projecting wall74is a generally vertical wall. It is contemplated that the surfaces72and76may be substantially horizontal and the wall74may be substantially vertical. The first generally upwardly projecting wall74encompasses and bridges the surfaces72,76. The second generally outwardly projecting surface72encompasses and extends outwardly from the peripheral sidewall68.

The second sealing area70of the lid14ofFIG. 2is an uninterrupted or continuous surface that extends around the entire periphery of the lid14. The second sealing area70as shown, for example, inFIGS. 2 and 3is spaced from the hinge16that assists in preventing or inhibiting leakage from the container10. Referring to the closed configuration ofFIGS. 3 and 4aspecifically, the second uninterrupted sealing area70sealingly engages the first uninterrupted sealing area40by use of matching surfaces. Specifically, the second generally outwardly projecting surface72of the lid14engages the second generally outwardly projecting ledge42of the base12; the first generally upwardly projecting wall74of the lid14engages the second generally upwardly projecting wall46of the base12; and the first generally outwardly projecting surface76of the lid14engages the first generally outwardly projecting ledge44of the base12.

According to another embodiment, as shown inFIG. 4b, a first generally upwardly projecting wall74bincludes an extension74cthat corresponds to a recess46cformed in second generally upwardly projecting wall46b. This extension and corresponding recess assist in forming a sealing area. The extension74cof the first generally upwardly projecting wall74band recess46cof the second generally upwardly projecting wall46bmay be used with the undercut50in securing the lid and the base as shown inFIG. 4b. Alternatively, the extension of the first generally upwardly projecting wall and recess of the second generally upwardly projecting wall may be used without an undercut. It is contemplated that the second generally upwardly projecting wall of the base may include an extension and the first generally upwardly projecting wall of the lid may form a corresponding recess.

It is contemplated that the first sealing area and the second sealing area may sealingly engage by using less than three surfaces. For example, it is contemplated that the first and second sealing areas may use one or two matching surfaces.

The diameter of the second sealing area70is preferably slightly greater than the diameter of the first sealing area40of the base12so as to create an amount of interference enforcing the surface-to-surface contact. This slightly greater diameter of the second sealing area70assists in allowing some tolerance in forming the base12and the lid14while still having a leak-resistant container. It is contemplated, however, that the diameter of the second sealing area70may be the same as the diameter of the first sealing area40. Similarly, in non-circular embodiments, the linear dimension of the second sealing area of the lid is preferably slightly greater than the linear dimension of the first sealing area of the base so as to create an amount of interference enforcing the surface-to-surface contact.

In the closed container configuration (FIGS. 2–4a), the lid14is locked onto the base12by having the second generally horizontal surface76of the lid14snap under the plurality of undercuts50in the base12. The plurality of undercuts50assists in maintaining the lid14and the base12in a closed position.

The lid14may also include at least one indentation such as, for example, a plurality of indentations82shown inFIG. 2. The indentation(s) may also be referred to as finger well(s). A user may position a finger and thumb in the plurality of indentations82and by squeezing, the second generally outwardly projecting surface76is moved from the plurality of undercuts50in effect unlocking the lid14from the base12to open the container10. The plurality of indentations82is located generally opposite of the hinge16to assist in opening the container from a closed position. It is contemplated that the indentation(s) may be located in a different position than depicted inFIG. 2. It is also contemplated that the lid may not have such an indentation such as shown in the lid114of container100ofFIG. 6.

The lid114ofFIG. 6also includes a sidewall168that includes a plurality of ribs134. The sidewall168of the lid114is designed to correspond with the sidewall120of the base112. The sidewall168includes a scalloped configuration that includes nine equidistant ribs like the sidewall120of the base112so as to be aesthetically pleasing with each other. The lid114also includes a tab extension136that assists a consumer in opening and closing the container100. The tab extension136of the lid112works in conjunction with tab extension152of the base112to assist in opening the container100.

The containers of the present invention are made of polymeric foam materials. It is contemplated that the foam containers may comprise materials such as alkenyl aromatic polymers, orientated polystyrene (OPS), polyolefins such as polypropylenes, polyesters such as polyethylene terephthalates (PET), high impact polystyrenes (HIPS), mineral-filled polymeric materials, or combinations thereof. Some non-limiting examples of mineral-filled polymeric foam materials include minerals such as talc, calcium carbonate or clay being used with foamed polymers such as polypropylenes, polyethylenes or polystyrenes. The lid and the base may be made from the same foam or a different foam.

The foam containers of the present invention are typically disposable, but it is contemplated that they may be reused at a future time. It is also contemplated that the foam containers may be made of materials that can be used in heating apparatus such as microwavable ovens and/or used in the dishwasher. The foam containers of the present invention preferably have a leak resistance when properly sealed that enable the containers to be held at different angles and shaken with no leakage.

The height and shape of, for example, the base12and/or the lid14may vary from that shown inFIGS. 1 and 2. The foam container10of the present invention is shown as being generally circular in shape. It is contemplated that the foam container may be of other shapes such as oval, and polygonal shapes like rectangular and hexagonal. It is desirable, however, to use a generally circular shaped container because of the high leak resistance achieved with such a shape. While not being bound by theory, it is believed that the stress is more evenly distributed using a generally circular shaped container, which results in an improved leak resistance.

The containers of the present invention may be formed using conventional thermoforming (e.g., by pressure, vacuum or the combination thereof). According to one method of thermoforming, pellets of a polymeric resin and additives, if any, are added into an extruder. The pellets of the polymeric resin and additives, if any, are melted to form a blend. The blend is extruded through a die to form an extruded sheet. The extruded sheet is thermoformed to a desired shape of a foam container.