WO1993006026A2

WO1993006026A2 - Recyclable food product tray with increased liquid collection and retention capability

Info

Publication number: WO1993006026A2
Application number: PCT/US1992/008182
Authority: WO
Inventors: Charles P. Kannankeril
Original assignee: Sealed Air Corporation
Priority date: 1991-09-27
Filing date: 1992-09-25
Publication date: 1993-04-01
Also published as: AU2766292A; WO1993006026A3

Abstract

A recyclable food product tray (20) having the ability to collect liquids exuded from a food product supported by said tray and to retain regardless of the attitude at which the tray is disposed. The tray includes an upper wall (21) for supporting a food product and a lower wall (22) which, together with the upper wall, defines an encapsulated region for collecting and retaining the liquids exuded from the food product. Liquids exuded from the food product are drained into the encapsulated region which is configured to restrict the flow of liquid from the encapsulated region back toward the food product.

Description

RECYCLABLE FOOD PRODUCT TRAY WITH INCREASED LIQUID COLLECTION AND RETENTION CAPABILITY

Field and Background of the Invention The present invention relates to a recyclable food product tray of the type used to contain and display various food products, and more particularly to 5. such a food product tray having an increased ability to collect and retain liquids exuded from a food product carried by the tray.

It has long been known that the liquids which seep from fresh meat or poultry are a significant 0 source of contamination within packaged meat or poultry products. This contamination arises from the growth of microorganisms, particularly bacteria and yeast, within the liquids, and when the liquids come into contact with the packaged food product, the product rapidly 5 becomes unsightly and thus unsalable. It is also known that these deleterious effects may be postponed by use of packaging systems which segregate the exuded liquids from the food product within the package.

In this regard, there have been disclosed 0 packaging systems which include a base tray which carries an absorbent pad of tissue-like paper wadding in the bottom of the tray to absorb any liquids exuded from a food product supported by the pad. Such systems often include a barrier layer between the absorbent pad and the food product to separate the exuded liquids from the food product. A transparent outer plastic wrapping may also be employed to cover and surround the food product and the tray to complete the package. Such a tray is disclosed in U.S. Patent No. 3,026,209 to Niblack. More recently, other packaging systems have been proposed to further improve the shelf-life of packaged food products. These systems focus on improving the extent of segregation between the food product and the exuded liquids. Examples of such improved packaging systems are disclosed in U.S. Patent Nos. 4,275,811 and 4,321,997, each owned by the assignee of the present invention.

In addition, U.S. Patent No. 4,949,897 to Pawlak discloses a food product tray which employs an internal reservoir to separate the carried food product from the exuded liquids. The Pawlak tray has first and second polystyrene layers joined at their outer edges to form a central support area, a reservoir area and a sidewall area. In use, the Pawlak tray captures liquids exuded from the food product between the two layers in the reservoir area. The tray is shaped such that when the tray is tilted slightly, the liquids contained in the reservoir will flow into the sidewall areas of the tray and will not easily pass back into contact with the carried food product.

Notwithstanding the advantages associated with the above described packaging systems, there remains a need for an improved packaging system which provides improved separation between the food product and the exuded liquids. In addition, given the numbers of such systems which are used and discarded by today's society, there is an ongoing need to further improve the recyclability or reusability of such systems.

Accordingly, it is an object of the present invention to provide a food product tray suitable for use as part of a food package system, which tray is characterized by the ability to substantially irreversibly collect liquids exuded from the food product carried by the tray and to retain such liquids regardless of the attitude at which the tray is disposed. It is a further object of the present invention to provide a tray suitable for use as part of a food package system, which tray may be easily recycled to eliminate any long term environmental effects. It is still a further object of the present invention to provide a food product tray which will effectively collect and retain liquids naturally exuded from the product without dehydrating the carried food product. In general, these objectives have been obtained in the present invention by providing a recyclable food product tray characterized by the ability to collect liquids exuded from a food product supported by the tray and to retain those liquids irrespective of the attitude at which the tray is disposed. The tray is constructed of upper and lower walls and which are positioned in registration with one another. The outer edges of the two walls are sealed together to define an encapsulated region between the two layers which region serves to substantially irreversibly collect and retain liquids drained from the upper wall.

The upper wall of the tray is additionally characterized by a support surface designed to carry a food product and also to facilitate drainage of liquids exuded from the product to the encapsulated region. This latter aspect is accomplished by providing in the support surface a fluid conduit in fluid communication with the encapsulated region of the tray. The fluid conduit depends downwardly into the encapsulated region, and preferably has a terminal opening positioned at a point more adjacent the lower wall than are the portions of the upper wall other than the portion from which the conduit depends. In this way, the majority of the volume defined by the encapsulated region is positioned away from the terminal opening of the conduit so that liquids in said encapsulated region tend to collect away from the terminal opening of the conduit. In normal usage, the fluid conduit provides drainage channels from the support surface of the upper wall, through the upper wall and into the encapsulated region. However, when the tray is disposed at other than a normal attitude, the conduits prevent reverse flow of the collected liquids back toward the support surface of the upper wall by effectively increasing the liquid capacity of the encapsulated region. Brief Description of the Drawings

Figure 1 shows a general perspective view of one embodiment of the present invention.

Figure 2 shows a cross-sectional view of the embodiment taken along line 2-2 of Figure 1. Figure 3 shows the same cross-sectional view as Figure 2, but at an inverted attitude.

Figures 4A and 4B illustrated normal and inverted views of an embodiment of the present invention having multiple fluid conduits. Figures 5 and 6 show embodiments having various improved fluid conduit structures.

Figures 7A and 7B depict an embodiment of the present invention wherein the fluid conduits provide support to the medial portions of the upper wall. Figure 8 illustrates an embodiment of the present invention wherein localized raised areas in the lower wall support the medial portions of the upper wall.

Figures 9A, 9B, and 9C illustrate various embodiments of the invention wherein the mouth opening of the fluid conduit is enlarged with respect to the terminal opening thereof. Figure 10 shows an embodiment having localized raised areas on the upper wall to support the food product.

Figures 11 and 12 show alternate shapes of the food product tray.

Figure 13 illustrates an embodiment wherein multiple indentations are provided in the lower wall of the tray to provide support to the overall tray and to impede lateral movement of the liquids retained within. the tray.

Figure 14 shows an embodiment of the present invention wherein a support shelf is included within the upper wall of the tray.

Figures 15A, 15B, 16A and 16B show normal and tilted views of two embodiments of the present invention wherein the lower wall is made from a flexible polymer film.

Description of the Preferred Embodiments

Referring more specifically to the drawings, there is shown in Figure 1 a perspective view of one form of a food product tray 10 of the present invention. As shown, the food product tray may take on a round overall shape; however, other overall shapes, such as square, rectangular, oval, etc., may be used to accommodate food products of various sizes and shapes. As more clearly illustrated in the cross- sectional view of Figure 2, the food product tray 20 of the present invention includes luid impervious upper and lower walls 21, 22, respectively. The upper and lower walls 21, 22 have coextensive outer edges 23 which are sealed together to define an encapsulated region 24 between the walls for retaining liquids exuded from the food product carried by the tray 20. As such, the upper and lower walls form fluid barriers to hold the exuded liquids within the tray 20.

The upper wall is characterized by a support surface 25 for supporting the food product within the tray 20, which surface preferably has a downwardly sloping medial portion. The support surface 25 includes a fluid conduit 26 for draining the liquids exuded from the food product away from the product and into the encapsulated region 24. The fluid conduit 26 is characterized by a downwardly depending portion 26a which is in fluid communication with the encapsulated region 24. Although any tubular shape will suffice, in the illustrated embodiment, the downwardly depending portion 26a conically converges toward the interior of the encapsulated region 24.

In this embodiment the fluid conduit is located at the nethermost portion of the support surface 25, which portion faces the lower wall 22 of the tray 20. Although the fluid conduit 26 may be located elsewhere on the support surface 25, the ability of the overall tray to substantially irreversibly segregate the carried food product and the collected liquids is, in large part, dictated by the location of the fluid conduit. That is, because the reverse flow of liquids from the encapsulated region to the support surface must be via the fluid conduit, the location of the conduit vis-a-vis the lowest portion of the encapsulated region at any given attitude will be all important in designing a tray which will effectively retain collected liquids. Thus, as shown in Figure 3, where the food product tray of Figure 2 is shown at an inverted attitude, the ability of the overall tray 20 to retain the collected liquids can be optimized by locating the fluid conduit 26 at or near the nethermost portion upper wall.

Figure 4A illustrates yet another embodiment of the present invention wherein multiple fluid conduits 46 are employed in a predetermined pattern across the support surface 45 of food product tray 40. In this embodiment, an alternative fluid conduit construction also is shown, wherein the downwardly depending portion 46a cylindrically extends into the encapsulated region 44. As shown in Figure 4B, where the fluid conduits are located toward the outer portions of the encapsulated region, it is advantageous to extend the fluid conduits further into the encapsulated region, preferably positioning the terminal opening thereof adjacent the lower wall. In this way, the threshold for the reverse flow of liquid back to the support surface is effectively increased, thus decreasing the importance of fluid conduit location vis-a-vis the retention capability of the tray.

Another embodiment of the present invention is shown in Figure 5, wherein the liquid capacity of the food product tray 50 is enhanced by terminating the downwardly depending portion 56a of the fluid conduit 56 with a U-shaped segment 59. In the preferred form of this embodiment, the U-shaped segment 59 should be oriented such that its terminal opening faces the central portion of the overall tray 50. In this way, the effective depth of the encapsulated region is optimized regardless of the attitude at which the tray is disposed. Of course, this terminal configuration may be used with either of the above described tubular, conical or cylindrical conduit configurations.

Further, as shown in Figure 6, the lower wall 62 may include one or more localized areas 68 which are depressed with respect to the upper portion of the wall and positioned to receive the terminal opening of the downwardly depending portion 66a of each fluid conduit 66. This construction, when used, further increases the liquid capacity of the tray 60 at unfavorable attitudes by even further raising the threshold for reverse flow of liquid back to the support surface of the upper wall.

Referring to Figure 7A, the upper wall 71 of the food product tray 70 can be supported by the lower wall 72 to insure the integrity of the encapsulated region 74. This is accomplished by extending the downwardly depending portion 76a of the conduit 76 to the extent that it rests on the lower wall 72. When 5 this embodiment is used, one or more drainage openings 77 should be formed adjacent the terminal end of the conduit 76 in order to avoid blockage of the conduit by the lower wall 72. Figure 7B shows an expanded cut-away view of a fluid conduit having a triangular- 10 shaped opening 77 formed adjacent the terminal end of the downwardly depending portion 76a of the conduit.

Alternatively, the encapsulated region may be supported from below by the lower wall as shown in Figure 8. In this embodiment, the lower wall 82 of the 15 tray 80 is characterized by one or more localized raised areas 85 which provide structural support for the upper wall 81, yet do not significantly lessen the liquid capacity of the overall tray 80.

As shown in Figures 9A and 9B, the fluid 20 conduit 96 may contain a downwardly depending portion 95a having a mouth opening which is larger than the terminal opening 97 thereof. Such an enlarged conduit aids in collecting the exuded liquid from larger regions of the support surface and segregating the same 25 from the source food product. Although as shown in

Figure 9A, the tray may contain a single enlarged fluid conduit 96, it is within the contemplation of the present invention that a plurality of such conduits may be employed and may take on whatever shape best 30 facilitates drainage of the exuded liquid from the carried food product.

One of the more preferred embodiments of the present invention, as shown in Figure 9C, includes multiple enlarged fluid conduits 96 having downwardly 35. depending portions 95a arranged in a predetermined pattern across the support surface 95. Each downwardly depending portion 95a has sloped sidewalls which extend over a major lateral portion of the support surface. In this embodiment, the fluid conduits are arranged in a star-shaped configuration which facilitates the collection of liquids from far reaching areas of the product tray and funnels the same toward the centrally- located terminal openings 97 which are in fluid communication. A nob 98 is positioned in the center of the tray to support the food product above the central portion of the surface 95. This construction has the advantage of being able to collect exuded liquids from far-reaching areas of the support surface, as well as a high liquid capacity due to its centrally-located fluid communication ports.

As shown in Figure 10, the upper wall 101 of the tray 100 may be further characterized by one or more localized raised areas 107. Such areas support the food product above the support surface 105 and fluid conduit 106 and thus provide better ventilation to the underside of the food product and enable more complete drainage of the exuded liquids into the interior of the tray.

As mentioned above, the shape of the respective upper and lower walls of the food product tray affect the liquid capacity of the tray by defining, in part, the volume of the encapsulated region. Accordingly, as shown in Figure 11, the upper and lower walls 111, 112, respectively, may be configured to optimize the volume of the encapsulated regions 114 and thus the liquid capacity of the tray 110.

Another alternative embodiment of the present invention is shown in Figure 12, wherein the upper and lower walls 121, 122, respectively, are shaped to distribute a larger portion of the volume of the encapsulated region 124 into the side portions of the overall tray. In this way, when the tray is tilted, larger portions of the retained liquids tend to collect away from the terminal opening of the fluid conduits. In this particular embodiment, the tray 120 further includes release means 123 for selectively releasing liquids retained by the tray 120 after its useful life has ended. Structures sufficient to perform this release function include, for example, a plugged or otherwise closed hole or a crushable nipple. In any event, the release means 123 is preferably located near the outer periphery of the tray 120 in order to maximize the extent to which the retained liquids may be released from the tray. The use of a release means facilitates the recycling of the spent tray materials.

Moreover, as shown in Figure 13, the lower wall 132 of tray 130 may comprise one or more cavities 133 for impeding lateral movement and splashing of the retained liquids within the encapsulated region 134. These cavities 133 may be localized or may extend longitudinally across the lower wall 132. in either case, the non-planar aspects of the lower wall in this embodiment imparts additional strength to the overall tray 130.

Referring to Figure 14, the support surface 145 of the upper wall 141 may be further characterized by a support shelf 147 positioned above the upper wall 141 to support the food product. In this embodiment, . the liquids flow into the encapsulated region 144 through the fluid conduit 146 located beneath the support shelf 147.

As shown in Figures 15A and 15B, the lower wall 152 of the tray 150 may be constructed of a flexible polymer film, such as a polyester like polyethylene terephthalate (commonly referred to as PET or MYLAR) , which has been sealed to the outer peripheral edges of the upper wall 151. This construction provides a flexible bag beneath the upper wall 151 to flexibly define the encapsulated region 154. In this embodiment, the configuration of the fluid conduits become less significant since the flexible lower wall 152 can accommodate more fluids in any given tilted position than could a more rigid bottom wall. Accordingly, as shown in Figures 16A and 16B, it is sufficient that the fluid conduits 166 have a shorter downwardly depending portions 166a so long as multiple ribs 167 are embodied on the lower surface of upper wall 161 to support the encapsulated region 164 and thus to segregate the retained liquid away from the supported food product.

As shown in Figure 2 , one or more pin holes 27 may be formed through the upper wall of the tray to vent the encapsulated region and thus to enhance the overall drainage efficiency of the tray. The vent holes improve the air-liquid exchange rate between the encapsulated region and the atmosphere within the overall food package, and thus enable faster and more complete drainage of the exuded liquids. These pin holes should be formed from the outside of the tray inward such that capillary action within the holes will prevent any appreciable leakage of the contained liquid.

The food product tray of the present invention is made by fabricating the upper and lower walls separately and then joining the two to produce the completed product. The walls may be made of any material which is generally impervious to liquids, including preferably non-metalics such as a foamed polymer, rigid plastic, compressed paper tissue or metals, metal foils or metal/nonmetal combinations. These materials may be shaped as needed by known processes, such as thermo-forming for plastics, wet-molding for paper materials or deep-drawing for metalics. Once the upper and lower walls are appropriately shaped the completed tray is made by sealing the peripheral edges of the walls together by any known sealing process, such as heat fusion, adhesive bonding, adhesive tape, or a mechanical interlock.

As shown in Figure 2, various additives 28 may be incorporated into the encapsulated region of the tray to improve its properties. For example, wood fluff, tissue paper, or a super-absorbent polymer, such as an acrylic acid salt polymer, may be included within the encapsulated region of the tray to absorb liquids collected therein. In addition, an anti-bacterial additive, such as potassium sorbate, sodium diacetate or sodium benzoate, may be included within the encapsulated region in order to provide bactericidal properties to the tray. And, finally, a food grade deodorizing agent, such as lemon scent, may be added to the encapsulated region of the tray to mask undesirable odors.

In the figures and specification, there have been disclosed preferred embodiments of the present invention. While specific terms are employed, they are used in a generic and descriptive sense only, and not for the purposes of limiting the scope of the invention as set forth in the following claims.

Claims

CLAIMS:

1. A food product tray having the ability to collect liquids exuded from a food product supported by said tray and to retain those liquids regardless of the attitude at which the tray is disposed, said tray comprising: an upper wall having a support surface for supporting a food product; a lower wall positioned in registration with said upper wall and sealed to said upper wall to define an encapsulated region therebetween for the retention of exuded liquids drained from said upper wall; a fluid conduit in said upper wall in fluid communication with said encapsulated region for draining liquids from said upper wall and into said encapsulated region, said fluid conduit depending downwardly into said encapsulated region, so that the majority of the volume defined by said encapsulated region is positioned away from the terminal opening of said conduit, whereby liquids in said encapsulated region tend to collect away from the terminal opening of the conduit so that said conduit and said encapsulated region substantially irreversibly collect any liquids exuded from the food product and retain those liquids regardless of the attitude at which said tray is disposed.

2. A food product tray according to Claim 1 wherein said support surface comprises a downwardly sloping medial portion having its nethermost portion positioned toward said lower wall.

3. A food product tray according to.Claim 2 wherein said fluid conduit is centered on said nethermost point of said surface.

4. A food product tray according to Claim 2 further comprising a plurality of said fluid conduits arranged in predetermined pattern across said support surface.

5. A food product tray according to Claim 1 wherein said fluid conduit is tubular.

6. A food product tray according to Claim 1 wherein said fluid conduit conically converges into the encapsulated region.

7. A food product tray according to Claim 1 wherein said fluid conduit cylindrically extends into the encapsulated region.

8. A food product tray according to Claims 6 or 7 wherein said fluid conduit further comprises a U-shaped terminal segment oriented such that the terminal opening thereof faces the central portion of said tray.

9. A food product tray according to Claim 1 wherein said lower wall comprises a localized area which is depressed in relation to said lower wall and positioned to receive the terminal opening of said fluid conduit.

10. A food product tray according to Claim 1 wherein the fluid conduit rests on said lower wall and has a drainage openings formed adjacent the terminal end thereof to prevent the lower wall from blocking drainage from the support surface to the encapsulated region.

11. A food product tray according to Claim 1 wherein said lower wall comprises one or more localized raised areas for supporting the upper wall.

12. A food product tray according to Claim 1 wherein said fluid conduit further comprises a mouth opening which is larger than said terminal opening to better facilitate the drainage of liquids from said support surface and into said encapsulated region.

13. A food product tray according to Claim 1 wherein said fluid conduit further comprises sloped sidewalls which laterally extend across said support surface to provide lateral drainage of liquids exuded from the food product from the outer periphery of the support surface to the central portion thereof for drainage into the encapsulated region.

14. A food product tray according to Claim 1 wherein said support surface comprises a localized raised area for supporting a food product above the fluid conduit to provide flow channels toward the encapsulated region.

15. A food product tray according to Claim 1 wherein said lower wall comprises a cavity for impeding the lateral movement of liquid retained within the encapsulated region.

16. A food product tray according to Claim 1 wherein said lower wall comprises a flexible polymer film.

17. A food product tray according to Claim 1 further comprising means for selectively releasing liquids which have been collected and retained within the encapsulated region.

18. A food product tray according to Claim 1 wherein said encapsulated region is vented to enhance the drainage capabilities of the tray.

19. A food product tray according to Claim 1 wherein said encapsulated region further comprises an absorbent material to enhance the liquid retention capability of said tray.

20. A food product tray according to Claim 1 wherein said encapsulated region further comprises an anti-bacterial additive to impede bacterial growth within said tray.

21. A food product tray according to Claim 1 wherein said encapsulated region further comprises a food grade deodorizing agent to mask undesirable odors within said tray.

22. A food product tray according to Claim 1 wherein said upper and lower walls comprise a material selected from the group consisting of foamed polymer, rigid plastic, compressed paper tissue, metals and metal foil.

23. A food product tray according to Claim 1 wherein the seal between said upper and lower walls is a seal selected from the group consisting of a heat seal, an adhesive bond, adhesive tape, or a mechanical interlock.

24. A food product tray according to Claim 1 wherein said support surface comprises a support shelf positioned above said upper wall, and said fluid conduit is located beneath said support shelf.

25. A food product tray having the ability to collect liquids exuded from a food product supported by said tray and to retain those regardless of the attitude at which the tray is disposed, said tray comprising: an upper wall having a downwardly sloping support surface for supporting a food product; a lower wall positioned in registration with said upper wall and sealed to said upper wall to define an encapsulated region therebetween for the retention of exuded liquids drained from said upper wall; a fluid conduit in said upper wall in fluid communication with said encapsulated region for draining liquids from said upper wall and into said encapsulated region, said fluid conduit depending downwardly into said encapsulated region; and a terminal opening of said fluid conduit positioned at a point more adjacent said lower wall than are the portions of said upper wall other than the portion from which said conduit depends, so that the majority of the volume defined by said encapsulated region is positioned away from said terminal opening of said conduit, whereby liquids in said encapsulated region tend to collect away from the terminal opening of the conduit so that said conduit and said encapsulated region substantially irreversibly collect any liquids exuded from the food product and retain those liquids regardless of the attitude at which said tray is disposed.

26. A food product tray according to Claim 25 wherein said fluid conduit is centered on said support surface.

27. A food product tray according to Claim 25 further comprising said fluid conduits arranged in predetermined pattern across said support surface.

28. A food product tray according to Claim 25 wherein said fluid conduit is tubular.

29. A food product tray according to Claim 25 wherein said fluid conduit conically converges into the encapsulated region.

30. A food product tray according to Claim 25 wherein each fluid conduit σylindrically extends into the encapsulated region.

31. A food product tray according to Claims 29 or 30 wherein said fluid conduit further comprises a U-shaped terminal segment oriented toward the central portion of said tray.

32. A food product tray having the ability to collect liquids exuded from a food product supported by said tray and to retain those liquids regardless of the attitude at which the tray is disposed, said tray comprising: an upper wall having a medial portion for supporting a food product; a lower wall sealed peripherally to said upper wall to define an encapsulated region between said walls for the collection and retention of liquids therein; a plurality of fluid conduits in said upper wall for draining liquids from said upper wall and into said encapsulated region, said fluid conduits depending downwardly into said encapsulated region, wherein said conduits each have a terminal opening therein which opening is positioned at a point more adjacent said lower wall than are the portions of said upper wall other than the portion from which said each conduit depends, so that the majority of the volume defined by said encapsulated region is positioned away from said terminal opening of said conduit, whereby liquids in said encapsulated region tend to collect away from the terminal opening of the conduit so that said conduit and said encapsulated region substantially irreversibly collect any liquids exuded from the food product and retain those liquids regardless of the attitude at which said tray is disposed.