Food Packaging Tray

Abstract

A food packaging tray is molded of wood pulp or plastic and is intended for the packaging of food products in conjunction with a transparent overwrap plastic film. The tray has an improved peripheral lip which resists inward collapse of the side and end walls of the tray from the pressure exerted by the transparent overwrap plastic film.

Parent Case Text

This is a continuation-in-part application of copending application, Ser. No. 246,600 filed Apr. 24, 1972, which in turn is a continuation-in-part of then copending application, Ser. No. 111,578 filed Feb. 1, 1971.

Description

FIELD OF THE INVENTION

The present invention relates to a food packaging tray and, more particularly, to a food packaging tray for use in the packaging of fresh meat, poultry, fish or produce in conjunction with a transparent overwrap film, and where an improved peripheral lip is provided to assist in preventing inward collapse of the side and end walls of the tray due to the pressures exerted by the overwrap film.

BACKGROUND

Food trays molded from wood or paper pulp or from clear or foam plastic are customarily used in most retail food markets today, particularly for the packaging of fresh meat, poultry, fish, produce or other commodities. These containers are usually in the form of shallow, generally rectangular trays in which the commodities are placed, with a transparent sheet or heat sealable cellophane or of heat shrinkable or stretchable plastic film tightly wrapped about the tray and heat sealed along the bottom to form a complete package.

Food trays play an important part in merchandising various commodities, and the ultimate appearance of the packaged food is an important factor in the sale of the product, i.e. a neat, clean-appearing package has an important relationship to the sales appeal of the goods being sold, and an unattractive package can be a sales deterrent. Accordingly, a tray for the packaging of such products should not have collapsed or cracked or broken side walls.

Additionally, with the advent of production line packaging, a vertical stack of food trays is generally stored in a hopper or magazine for either mechanical and/or manual denesting prior to packaging, and it is important that molded trays be readily denestable by providing sufficient denesting clearance between adjacent nested trays. In particular, the area of the lip normally provides a good denesting area.

Furthermore, the food packaging trays must be strong enough to resist rough handling and retain their shape and appearance, not only for the reasons indicated above with regard to sales appeal, but also to maintain the packaged food in a clean environment, to protect the food from physical damage, and to prevent spilling of the goods from a damaged container.

Additionally, food trays are one-use, throw-away items and for this reason the cost must be kept to a minimum. Thus, while the strength, neat appearance and ability to form a good package must be maximized, the cost of the package must be minimized since it is entirely a merchandising cost.

Molded wood or paper pulp food trays have served the food packaging industry well for many years for the packaging of meat, fish, poultry and produce. Such trays have the advantage, besides low price and low cost to the consumer, of being clean, sturdy and safe; of being biode-gradable so as to minimize the solids pollution problem; of being capable of assimilating the free juices which exude from some meats and poultry; and of being air and vapor permeable so as to maintain color and freshness of meat. Thus, the molded wood pulp trays previously manufactured were very satisfactory for the purpose for which they were intended; however, a constant endeavor is being made to afford even better trays without an increase in cost to the retailer or ultimate consumer.

Paperboard trays, i.e. cut and scored trays formed from flat sheets of paperboard, are not especially adapted for use with shrink and stretch plastic films, since the side walls of such board trays do not have the requisite side wall characteristics to afford uniformly appearing packages after overwrapping with the film. Foam plastic trays are in general not sufficiently strong, are not usually biodegradable, cannot assimilate free juices and are not air and vapor permeable. The so-called clear plastic trays have even greater defects; besides having all the defects of the foam plastic trays mentioned above, they often have sharp edges which cut the overwrap film permitting contamination of the food products and leakage of the contents and, in addition, color and freshness of meat packaged in such trays are not normally maintained very long.

Earlier trays molded of wood pulp were first produced without an upper peripheral lip. These trays were highly practical and satisfactory for the purpose intended. Later trays had essentially straight side walls and a flat peripheral lip; these trays served the trade successfully for many years and leant themselves to form a highly desirable package when wrapped with non-shrink or non-stretch films such as heat-sealable cellophane. However, as the nature of transparent plastic wrap film changed and non-elastic and non-shrink cellophane was replaced with more elastic thermoplastic shrink or stretch overwrap films, the tray in accordance with the Reifers U.S. Pat. No. 3,185,371 was developed, improving the tray performance.

SUMMARY

The present invention involves a novel tray and package and incorporates the desirable advantages and benefits of prior trays and is especially designed for use with heat-shrinkable or stretchable overwrap plastic film, although it may be used as well with heat-sealable cellophane. This novel tray and package formed therewith give increased benefits to the consumer without an appreciable increase in cost.

It is, accordingly, an object of the present invention to overcome the deficiencies of the prior art, such as indicated above.

It is another object of the present invention to provide for the improved packaging of food products.

It is another object of the present invention to provide an improved food tray for the packaging of meat, fish, poultry or produce.

It is another object of the present invention to provide a food tray which may be fabricated of various materials, and one which is preferably molded of wood pulp or plastic.

It is another object of the present invention to provide a molded, nestable tray, preferably of wood or paper pulp or the like, for the packaging of meat, fish, poultry or produce, which has increased side wall cave-in resistance.

It is another object of the present invention to provide for the clean, safe and effective packaging of food products.

It is another object of the present invention to provide a food packaging tray which is not only effective but which is inexpensive.

It is another object of the present invention to provide a molded food tray which affords a substantially rectangular appearance before and after a package is formed therewith, which is adapted for use with a package forming wrapper, and which provides for a special structure and shape maintaining the desired rectangular shape and resistance to internally directed forces on side walls when forming a package utilizing a shrink or stretch film.

A still further object of the present invention is to provide a novel food tray which includes an improved peripheral lip structure insuring improved nesting and denesting clearances.

And yet another object of the present invention is to provide a novel package which includes improved structure to present a substantially rectangular appearing package of greater strength than was heretofore thought possible.

It is another object of the present invention to provide a construction which reduces movement of exuded liquids from the inside to the outside of the package.

These and other objects in the nature and advantages of the instant invention will be more apparent from the following detailed description of a specific embodiment, such a specific embodiment being described below with reference to the attached drawing, it being understood that such embodiment is intended as merely exemplary and in no way limitative.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a tray in accordance with the present invention;

FIG. 2 is a vertical sectional view taken along line 2--2 of FIG. 1;

FIG. 3 is a vertical sectional view taken along line 3--3 of FIG. 1; and

FIG. 4 is a partial sectional view showing a completed package.

DETAILED DESCRIPTION OF EMBODIMENT

A novel food tray in accordance with the present invention is shown generally at 10 in FIG. 1. The tray 10 has a suitable bottom wall 12 of any desired configuration, such as that shown in parent application, Ser. No. 246,600, although for simplicity a simple flat, uniform and imperforate bottom is shown. In addition the tray has a pair of opposite facing side walls 14 and a pair of opposite facing end walls 16. Extending about the upper edge of the walls 16 and 14 and integral therewith is a downwardly angled, peripheral lip 18, the details of which form the major aspects of the present invention, and which are described in greater detail below. The side walls 14 and end walls 16 are preferably arcuately bowed as is described in the Reifers U.S. Pat. No. 3,185,371.

Referring to FIG. 4 there is seen a cut of meat 22 packaged using the tray of the present invention in conjunction with an overwrap transparent film 25. The peripheral lip 18, as is best seen in this figure, has an outwardly extending horizontal terminal portion 19 and an upper rounded domed portion 20. The horizontal terminal portion 19 is located at a level substantially below the top of the domed portion 20; furthermore, the portion 19 extends outwardly far more than do the conventional lips heretofore used in prior practice.

As seen in FIG. 4, the film 24 contacts the lip 18 along two distinct and separated portions, i.e. the end of the terminal portion 19 and the top of the domed portion 20 and this provides a double gasket or sealing function. With the "problem cuts" of beef, namely the 10-15 percent of packaged meat which bleeds profusely, the peripheral lip 18 tends to prevent the travel of free liquid by capillary action between the film 24 and the lip from the inside to the outside of the tray 10 where it would cause the plastic heat seal of the plastic film 24 to open effecting leakage and unwrapping of the package, besides providing an unsightly appearance.

However, the lip 18 has highly important mechanical advantages regardless of the product packaged in the tray. The lip 18 is provided with a greater material mass which provides additional beam strength and also has additional cave-in resistance strength so as to resist inward force provided by the tension exerted by the stretched film 24. In addition, the horizontal portion 19, being at a height considerably lower than the domed portion 20, absorbs inwardly directed forces in a manner that stresses the side wall less because the resultant lever arm is lower, e.g. 30-35 percent lower. Additionally vector analysis shows that the net effect in inward deflection resulting from inward force is reduced and there is 12 percent less bending moment.

Thus, it would be understood that the horizontal portion 19, as illustrated, is at a height of about two-sevenths, or even more, of the distance from the top to the bottom of the tray.

While the tray of the present invention is preferably molded of conventional wood or paper pulp stock which may be formed or preformed from a water slurry, it will be understood that the construction provided is particularly suitable to the manufacture, preferably by molding, of trays from other materials, particularly foam plastic or even solid plastic. Thus, the tray of the present invention may be formed of other, equivalent materials, the structural advantages of the tray deriving from its geometry. Among other materials there may be mentioned conventional polystyrene foam, structural cellular polystyrene foam, porous polyolefin material, open cell polystyrene foam, or biodegradable foam polystyrene. If formed of materials having different strength characteristics, certain advantages may be absent.

When the tray is molded of a special wood pulp having a large capacity to accept free liquids, the tray 10 has particular effectiveness in the packaging of the "problem cuts" of meat or "heavy bleeders," as they are often called. In such cases the combination of the special furnish and the double gasket seal provided by the lip 18 effectively prevents the movement of exuded fluids from the inside to the outside of the tray.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification.

Claims

What is claimed is:

1. In a generally rectangular molded tray for the packaging of meat, fish, poultry or produce in conjunction with a transparent overwrap film heat-sealed thereabout, said tray comprising: a pair of upwardly and outwardly inclined side walls, each said side wall forming a long side of said tray; a pair of upwardly and outwardly inclined end walls, each said end wall being adjacent to ends of said side walls, and thereby forming the rectangular configuration of said tray; a generally rounded corner between each said side wall and each said end wall; bottom wall means for supporting the meat, fish, poultry or produce comprising a bottom wall connecting the bottom portions of said end and side walls; and a peripheral lip extending outwardly from said side and end walls and defining the periphery of the tray, the improvement wherein

said peripheral lip comprises a relatively large and thick portion dome-shaped in cross-section defining the uppermost portion of the tray, and a horizontal portion extending outwardly from said dome-shaped portion at a location substantially below the top of the dome-shaped portion.

2. A tray in accordance with claim 1 wherein said end and side walls are bowed.

3. A tray in accordance with claim 2 of wood pulp.

4. A tray in accordance with claim 3 wherein said wood pulp tray has a large capacity to accept free liquid.

5. A tray in accordance with claim 2 of foam plastic.

6. A tray in accordance with claim 1 wherein said horizontal portion of said lip is located at least two-sevenths of the distance from the top to the bottom of the tray.