Cross Reference to Related

This application is based on U.S. Provisional Patent Application No.63/316,482, filed March 4, 2022, which is hereby incorporated by reference in its entirety.

Technical Field

This invention relates to pressware paper plates with tall dividers formed therein to define a plurality of serving compartments for food items.

Many consumers prefer to separate different foods from each other on their plate when consuming them. Without dividers, foods and liquids can mix or flow into each other thus making it difficult to maintain separation between different food portions during a meal. Various types of compartmented disposable plates have been available for many years. Some of these are described in more detail below.

Pulp-molded paper, foamed, and solid plastic compartmented plates can be readily manufactured with tall dividers between the compartments due to their respective methods of manufacture. The pulp molded plates are made by dipping the mold in a fiber slurry thus distributing the fibers over the plate and compartmented divider surfaces. Solid and foamed plastic compartmented plates are produced by thermoforming, heat softening and vacuum stretching the material into the plate mold over the shape. See United States Patent No. 6,440,509 to Litlejohn et al. These products tend to be relatively expensive though vs. pressed paper plates due to their material and/or manufacture method costs. There is also an increased awareness and pressure on these products from environmental concerns (i.e. Perfluorooctanoic acid or PFOA's in pulp molded plates, and single use plastic products) vs. renewable, recyclable, compostable paper alternatives.

Manufacturers have successfully produced and sold pressed paper compartmented plates. The pressed paper compartmented plates commercially sold have low divider heights (< 5/16") and/or inferior profiles without an outer downturn (i.e., flat flange) resulting in lower product rigidity and food load capability. Taller (> 7/16") compartmented pressware plates that have been available have a flat flange with no outer downturn. A square compartmented pressware plate is seen in United States Patent No. 5,236, 119 to Chu. Applicant has previously commercially sold a nominal 10" three compartmented plate with an outer downturn (Dixie® Kids™) that used a 4 radius profile, but only had 9/32" (0.281") tall dividers. Applicant has also previously commercially sold a nominal 9" three compartmented plate with an outer downturn (Krazy Kritters™) that also used a 4 radius profile, but only had 0.25" tall dividers. The four radius profile is described in United States Patent No. 5,088,640 to Litlejohn. Pactiv recently introduced an EarthChoice® brand three compartment pressed paper plate that has 3/16" (0.188") tall dividers. All of these pressware plates have lower compartmented divider heights vs. the pulp molded and foamed/solid plastic products which typically have 1/2" or taller divider heights. The lower divider heights only marginally prevent the foods / liquids from mixing with each other.

Pactiv has also sold a three compartmented 7-3/8" diameter pressed paper plate referred to as ZooPais which had 5/8" (0.625") tall dividers, but the plate did not have an outer downturn and was relatively low strength. The two additional compartments were smaller in size and external to the central portion of the plate and meant for condiments such as ketchup with a capacity of about 1 ounce each. See United States Patent No. 7,484,344 to Schiltz et al.

In contrast to pulp molded plates, pressed containers can easily have a continuous functional coating applied to the paperboard prior to forming, resulting in enhanced performance with hot and moist foods; however, forming structural features for pressware paper plates is much more challenging than is the case with pulp molded or plastic plates. The various technologies by which plates are formed, i.e. pulp-molding, paperboard press-forming and thermoforming are not interchangeable, especially in view of the drastic differences in the physics by which plates are formed in these processes. In particular, the necessity of forming strong pleats imposes severe constraints on formation of pressed paperboard plates which are not present in the other formatting technologies. When a container is made by pressing a paperboard blank, the flat blank must be distorted and changed in shape and area in order to form the blank into the desired three-dimensional shape. This necessary distortion results in seams or pleats in the sidewall and rim, the areas of the container which are drawn in toward the center in pressforming the container, resulting from the decrease in the circumference of the formed container as compared to the blank. Unless considerable care is employed during the process of pressing, these seams or pleats can constitute material lines of weakness in the sidewall and rim areas about which such containers tend to bend more readily than do containers having unpleated sidewalls and rims. Forming tall dividers in a pressware plate introduces additional complexities, including pleat forming in undesired areas, hinging of the product and tears in the paperboard, especially in 3 dimensional corners between the bottom, the plate sidewall and the divider sidewall.

Summary of invention

It has been found that various features enable the manufacture of strong and rigid pressware plates with tall dividers with a minimum of formation and stacking issues. The plates of the invention have surprising rigidity and strength.

There is provided in a first aspect of the invention a rigid compartmented pressed paper plate with an outer downturn and tall compartment divider heights; preferably with divider heights >9/32" >7/16" or >1/2". Compartmented plates of the invention with tall dividers separates foods/liquids from each other and can hold >lb of food when held with one hand without buckling or breaking. The inventive plate typically has a FPI geometric mean plate rigidity (MD*CD) ^A 0.5 > about 100 grams. “FPI” refers to Foodservice Packaging Institute which provides a rigidity tester for plates, discussed below. Plates of the invention also exhibit a “one hand hold” (lab test) typically of > about 1 lb in the large compartment which simulates the maximum capacity of the plate to support a food load while being held in one hand.

As seen in the examples which follow, the outer downturn provides surprising rigidity and strength to the product.

There is provided in a second aspect of the present invention a compartmented pressed paper plate as set forth in the first aspect noted above being further provided with variable radii along divider sidewall(s) to bottom(s) junctions along length(s) to blend 3D corners where paper tears can occur due to localized over stretching. The variable radii optionally may occur in separate areas as shown in the accompanying Figures and described herein. The variable fillets around the plate resolve forming issues, especially tears in the paper due to over-stressing of the paperboard during manufacture. While the fillets reduce compartment volumes somewhat, the effect is minimized by localizing the fillets to 3D corners.

There is provided in a third aspect of the present invention a compartmented pressed paper plate as set forth in the first aspect noted above being further provided with localized height drops (“dip-downs”) at the ends of the divider(s) where the dividers meet the plate sidewall to assist with the take-up of the paperboard materials to prevent localized material pleating/webbing that can result in stack stability issues / tilting, and/or to increase product strength by reducing the hinging tendency of the dividers when the plate is flexed in the machine-direction with the dividers between the two smaller and one larger compartment in a three compartment plate aligned in the cross-direction (+6% per FEA computer modeling). While the plate will flex it will not fail under typical food loads up to about 1 pound. Preferably the height drops or dip downs are >1/8".

There is provided in a fourth aspect of the present invention a compartmented pressed paper plate as set forth in the first aspect noted above being further provided with extra material downturn length lobes (“dog-ears”) at the ends of the divider(s) that provide localized enhanced strength and further reduces divider hinging tendency when flexed. The lobes align with each other in a stack and have acceptable aesthetics thus not requiring post trimming after forming. The lobes result during the formation process since paperboard at the ends of the dividers does not need to be pulled into the die set as much as in other locations between dividers, such that the lobes extend downwardly more than adjacent areas of the flange of the plate. While the lobes can be post-trimmed after formation as noted above, it has been found they do not interfere with stacking and unexpectedly provide a modicum of increased strength to the product.

A particularly preferred embodiment of the invention combines the various features noted above. There is thus provided in accordance with the present invention a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom defining a bottom surface adjoining and transitioning to a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom, the plate sidewall defining a plate sidewall surface and adjoining a flange flaring outwardly from the sidewall, the plate further comprising one or more tall dividers each having a pair of divider sidewall surfaces and adjoining the plate bottom which transitions to the divider sidewall surfaces, wherein the one or more tall dividers are characterized by a divider height, DH, from the bottom of the plate greater than 9/32", said one or more tall dividers extending from the sidewall toward a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments. The flange is characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex if the flange, wherein the ratio of V:H is from about 0.1 to about 0.75. Transitions between adjoining surfaces of the bottom surface and the divider sidewall surfaces are characterized by variable radii of curvature wherein the variable radii of curvature vary from a first value proximate to transitions between two surfaces to a second value higher than the first value at transitions proximate to the intersection of three surfaces; the variations are preferably progressive over an intermediate distance so as not to interfere with the smoothness of filleted areas of the plate surfaces. The dividers adjoin the sidewall of the plate at a height, SDH, less than DH (thereby defining a divider “dip down”), and the flange is optionally provided with an enhanced downturn in the vicinity of a junction of the one or more dividers with the sidewall, the enhanced downturn having lobes extending downwardly more than adjacent portions of the flange.

An inventive rigid pressed paper compartmented round plate described (and exemplified) herein has an outer downturn and taller dividers (>7/16") that together provide a functional pressed paper, lower cost option for consumers. The nominal 10" diameter circular plate described in connection with Figures 1 to 15 has U" tall dividers with a 10-1/4" diameter profile based on the profile described in United States Patent No. 6,715,630 to Litlejohn et al. entitled “DISPOSABLE FOOD CONTAINER WITH A LINEAR SIDEWALL PROFILE AND AN ARCUATE OUTER FLANGE”. This plate requires a 11.562" diameter blank, which is slightly larger than the 11.094" diameter blank used to form a similar plate without compartments due to the extra material length to form the dividers and can be formed 4 across in a 57" wide press forming system, and 5 to 6 across in a 70" wide press forming system. The blank used to make the exemplified compartmented product has (48) radial scores for pleating having lengths of 1.422" each. Ideally, scores would also be used at the divider junctions to control material gathering there, but with the round blank that can rotate after blanking before forming, the exact location of these scores in the forming cannot be determined; accordingly centrally located scores are omitted for round plates.

For polygonal containers or plates, centrally located scores on the blanks may be employed to facilitate formation.

Further details and advantages are described below in connection with the appended Figures.

Brief Description of Drawings

The invention is described in detail below with reference to the drawings wherein like numerals designate similar parts and wherein: Figure 1 is an isometric top view of a compartmented pressware paper plate of the present invention;

Figure 1 A is an isometric top view of a compartmented pressware paper plate of Figure 1 showing pleats around the plate sidewall and flange of the plate;

Figure 2 is a top view of the compartmented pressware paper plate of Figure 1 identifying 3-dimenional corners where tears can occur during forming;

Figure 3 is a top view of the compartmented pressware paper plate of Figure 1 identifying locations of variable fillets;

Figure 4 is a top schematic view of the compartmented pressware paper plate of Figure 1 illustrating lobed downward projections of the rim associated with the dividers of the plate;

Figure 5 is a schematic diagram illustrating a profile of the compartmented pressware paper plate of Figure 1;

Figure 6 is a schematic diagram illustrating a sidewall and flange profile of the compartmented paper plate of Figure 1, wherein the dividers are omitted for purposes of illustration;

Figure 7 is a top plan view of the compartmented pressware paper plate of Figure 1 illustrating the geometry of the central junction of the compartment dividers;

Figures 8 and 8A are schematic diagrams illustrating cross-section dimensions of a divider of the compartmented pressware paper plate of Figure 1;

Figure 9 is a schematic diagram illustrating profile dimensions along a divider of the compartmented pressware paper plate of Figure 1;

Figure 10 is a schematic diagram illustrating profile dimensions of a dip down of a divider and its junction with the plate sidewall of the compartmented pressware paper plate of Figure 1;

Figures 11 to 13 are enlarged partial top views of the compartmented pressware paper plate of Figure 1 illustrating optional variable radii of curvature between the sidewalls of the dividers and a central junction of the plate with the bottom of the compartmented paper plate of Figure 1;

The bold lines on Figures 11 to 13 indicate the visually observable borders of the fillets and transitions between the plate bottom and the plate or divider sidewalls;

Figure 14 is a top plan view of a compartmented pressware plate having various features of the plates of Figures 1 to 13 illustrating the arcuate trajectory of longer ribs from the central divider junction of the plate to the sidewall of the plate;

Figure 15 is another top plan view of a compartmented pressware plate of Figure 14;

Figure 16 is a schematic diagram illustrating FPI rigidity measurements on a pressware plate;

Figure 17 is a schematic diagram illustrating load to failure measurements on a pressware plate;

Figure 18 is a top isometric view of an octagonal paper pressware plate of the invention having the various features described in connection with Figure 1 through 15;

Figure 19 is a top plan view of the octagonal paper pressware plate of Figure 18 illustrating the arcuate trajectory of the longer ribs from the central divider junction of the plate to the sidewall of the plate; and

Figure 20 is a top plan view of a scored paperboard blank for making the octagonal paper pressware plate of Figures 18 and 19 illustrating the arcuate trajectory of the longer ribs from the central divider junction of the plate to the sidewall of the plate.

Detailed Description

The invention is described in detail below in connection with the Figures for purposes of illustration only. The invention is defined in the appended claims. Unless otherwise indicated, terminology and symbols used herein is given its ordinary meaning consistent with the exemplary definitions set forth immediately below; for example “in.” or " or like terminology following a numeric value indicates inches; # indicates pounds, ft2 or fts indicates square feet and so forth. The center of a circular plate is the point equidistant from the circumference. In the case of plates having a regular polygonal shape, the center is the point that is equidistant from each vertex or comer. It is also the center of the regular polygon's incircle and circumcircle. For plates having an irregular polygonal shape, or other shape such as an ovoid, ellipsoid or combinations of shapes, the center as the term is used herein is the centroid (center of area) which comes from considering the surface of the shape as having constant density.

A central portion of the plate bottom, a central junction on the plate where the tall dividers meet and like terminology refers to structures proximate the center of the pressware plate.

“Characteristic diameter”, “plate diameter" and like terminology refers to the diameter of a circular plate, or is equal to 2X A/K (or in alternate representation (4 A/K) ^1/2 ) for other shapes, where A is the projected area of the finished plate. In a preferred embodiment, plates of the invention have a characteristic diameter of from about 8" to 12".

A fillet characteristic radius of curvature refers to a maximum radius of curvature between a divider sidewall and the plate bottom in a fillet.

FPI Rigidity and One Hand Load to Failure testing are carried out as described below. FPI rigidity may also be calculated with finite element analysis (FEA) for purposes of evaluating designs.

“Proximate”, “in the vicinity” and so forth refers to a distance between recited elements of generally 0.35 times the characteristic diameter of the plate or less; typically to a distance between recited elements of 0.25 times the characteristic diameter of the plate or less, and in most cases to a distance between recited elements of 0.1 times the characteristic diameter of the plate or less .

Pressware paperboard plates are a preferred option for disposable plates since the paperboard stock can be typically impregnated with starch and coated on one side with a liquid proof layer or layers comprising a press-applied, water-based coating applied over the inorganic pigment typically applied to the board during manufacturing. Carboxylated styrene-butadiene resins may be used with or without filler if so desired. In addition, for aesthetic reasons, the paperboard stock can be often initially printed before being coated with an overcoat layer. As an example of typical coating material, a first layer of latex coating may be applied over the printed paperboard with a second layer of acrylic coating applied over the first layer. These coatings may be applied either using the conventional printing press used to apply the decorative printing or may be applied using some other form of a conventional press coater. Coatings that can include two pigment (clay) containing layers, with a binder, of about 6 lbs/3,000 ft ² ream or so followed by two acrylic layers of about 0.5-1 lbs/3,000 ft ² ream. The clay containing layers are provided first during board manufacture and the acrylic layers are then applied by press coating methods, e.g., gravure, coil coating, flexographic methods and so forth as opposed to extrusion or film laminating methods which are expensive and may require off-line processing as well as large amounts of coating material. An extruded film, for example, may require 25 lbs/3,000 ft ² ream.

A layer comprising a latex may contain any suitable latex known to the art. By way of example, suitable latexes include styrene-acrylic copolymer, acrylonitrile styrene-acrylic copolymer, polyvinyl alcohol polymer, acrylic acid polymer, ethylene vinyl alcohol copolymer, ethylene-vinyl chloride copolymer, ethylene vinyl acetate copolymer, vinyl acetate acrylic copolymer, styrene-butadiene copolymer and acetate ethylene copolymer. The layer containing latex can include, but can be not limited to, one or more of styrene-acrylic copolymer, styrenebutadiene copolymer, or vinyl acetate-acrylic copolymer. In some examples, the layer containing latex can include vinyl acetate ethylene copolymer. The layer containing latex can include a latex that can be pigmented. Pigmenting the latex increases the coat weight of the layer containing a latex thus reducing runnability problems when using blade coaters to coat the substrate. Pigmenting the latex also improves the resulting quality of print that may be applied to the coated paperboard. Suitable pigments or fillers include kaolin clay, delaminated clays, structured clays, calcined clays, alumina, silica, aluminosilicates, talc, calcium sulfate, ground calcium carbonates, and precipitated calcium carbonates. The pigment can include kaolin clay and conventional delaminated coating clay. The layer comprising a latex may also contain other additives that are well known in the art to enhance the properties of coated paperboard. By way of example, suitable additives include dispersants, lubricants, defoamers, film-formers, antifoamers, and/or crosslinkers.

Typically, paperboard for pressware containers can include up to about 6 lbs/3,000 ft ² starch; however, the rigidity can be considerably enhanced by using paperboard of about 9 to about 12 lbs/3,000 ft ² starch, as further discussed in U.S. Pat. Nos. 5,938,112 and 5,326,020, the disclosures of which are incorporated herein by reference. The plates of the invention are prepared from a substantially planar paperboard blank, which is moistened, impregnated with starch and scored prior to insertion and forming in a segmented pressware die-set. The blank may have anywhere from about 35 to 65 scores about its periphery for forming the rim, having a length of from about 1.25" to 1.75". Further details are provided in United States Patent Nos. 8,584,929 to Litlejohn et al. 8,047,834 to Sofronie et al , and 6,783,720 to Johns et al., as well as in United States Patent Application Publication No. 2017/0065110.

When forming the compartmented pressware of the present invention, it is preferable to form the dividers to their full height, or substantially their full height, prior to final pressing of the container rim in order to reduce tearing of the blank during processing. “Substantially full height” may be anywhere from 75% to 100% of the full height of the dividers in the finished product.

Referring to Figures 1 to 15, there is illustrated a circular compartmented pressware plate 10 having a plate bottom 12 defining a plate bottom surface 14 (which may be planar or have a slight crown) adjoining and transitioning to a plate sidewall 16 extending around bottom 12 and projecting upwardly and outwardly therefrom. The plate sidewall defines a plate sidewall surface 18 which adjoins a flange 20 flaring outwardly from sidewall 16. Plate 10 defines 3 tall dividers 22, 24 and 26, divider 22 being of shorter length between compartments 28, 30 and dividers 24, 26 having a longer length between compartments 30, 32 and 28, 32 as shown. The pressware plates of the invention are prepared from scored paperboard blanks as noted above and have a plurality of pleats, P, as indicated on Figure 1 A. The pleats are omitted from the other figures for purposes of illustration.

As is appreciated from Figure 2, plate 10 has a plurality of 3 -dimensional corners 34 where 3 surfaces intersect; that is, where a sidewall surface, a tall divider sidewall surface and a plate bottom surface intersect, for example, or where 2 divider sidewall surfaces and a bottom surface intersect. Due to geometry demands on the paperboard, tears can occur in these regions during forming of pressware plate 10 when making a plate with tall dividers.

In order to ameliorate tearing at the 3-dimensional comers 34, there is provided a first plurality of variable fillets 36, optionally a second plurality of variable fillets 38 and a third plurality of fillets 40, as indicated on Figure 3 and described hereinafter. Another feature which eases forming issues with tall dividers and provides an area to gather excess material are the “dip downs” or height reductions of the dividers where they meet the sidewall of the plate.

Referring to Figures 4 and 5 it is seen plate 10 has 3 divider height reductions or “dip downs” 42, 44 and 46 adjoining the sidewall of plate 10, as well as lobes 48, 50, 52 radially aligned with height reductions 42, 44, 46, respectively; that is, in their respective vicinities around flange 20.

Figure 5 is a schematic diagram illustrating the profile of plate 10 along divider 22 and extending between compartments 28, 30. The plate is characterized by a diameter through the plate center of a length, D, of about 10.25", a flange height, H, at its apex of about 0.8" from plate bottom 12, a divider height, DH, of about 0.5" from the bottom of the plate and an intersection of divider 22 with sidewall 16 at a lesser height, SDH, of about 0.3" to about 0.4" from the bottom of the plate 12. Lobes 48, 50 and 52 extend downwardly an additional distance, L, from about 0.05" to 0.25" more than adjacent portions of the flange as may be appreciated from Figures 5 and 6.

The “dip downs” and lobes allow stackability of the plates and provide a modicum of strength enhancement, as discussed hereinafter.

Figure 6 illustrates schematically to overall profile of plate 10 (without dividers shown). Values of various dimensions are provided in Table 1 below. R = ’A D.

Table 1 Plate Forming Die Dimensions

*V value in Table 1 is for the downturn proximate to a divider. The value of V may vary substantially around the plate, with lesser values between dividers.

From Figures 5 and 6 it is appreciated that flange 20 has a significant downturn 54 at its outer periphery; downturn 54 extending downwardly a distance, V, of around 50% of height, H, from the apex (highest point of the flange) in the vicinity of a divider. The ratio V:H is suitably from 0.1 to 0.75.

The dimensions in Table 1 are forming die set values which correspond to those of formed plate 10. For present purposes, the transition characterized by radius of curvature, Rl, is considered to be part of both plate bottom 12 and plate sidewall 16.

Referring to Figure 7, there is shown a top plan view of plate 10 wherein it is seen a central junction 56 defined by dividers 22, 24 and 26 is formed near the center 58 of plate 10 which is at the intersection of two plate diameters, D. Central junction 56 is radially offset from center 58 by a distance 60 of about 0.6". That is, central junction 56 is formed by the intersection of dividers 22, 24 and 26 and the intersection is centered slightly offset from center 58 of plate 10. Divider 22 is aligned along a diameter, while dividers 24, 26 are aligned in a direction offset by an angle of 15° from a diameter as shown. Each of the dividers have terminal portions 62, 64, 66 at plate sidewall 16 and medial portions 68, 70 and 72 between 3-dimensional comers. The 3 tall dividers are in a Y configuration with sweeping direction changes characterized by a radius of curvature, R4, which is suitably of a length of from 0.75" to 1.5" such as 1.062" or 1.281" or 1.438" for a nominal 10" diameter plate.

In a preferred embodiment, terminal portions 62, 64, 66 and medial portions 68, 70 and 72 of dividers 22, 24 and 26 have the structures further described below in connection with Figures 8, 8 A, 9 and 10.

Figure 8 is a cross-section of medial portion 68 of divider 22 wherein it is seen the divider has a linear sidewall portion 74 which makes an angle of 30° with a vertical from the plate bottom. Divider 22 transitions from plate bottom 12 at a radius of curvature, R5, and has a curved top portion 76 defining a radius of curvature, R6. R6 and R5 may both have a length of 0.188". The divider has a height, DH, of 0.5" as noted above, as well as a pair of divider sidewalls 22A and 22B as shown.

Figure 8A is a top view of terminal portion 62 of divider 22, wherein it is seen that top portion 76 of the divider has a smaller radius of curvature R7 of about 0.06" at the end of the divider, that is, where the divider height reduction begins.

Figure 9 is another profile of plate 10 along divider 22. It is seen that terminal portion 62 of divider 22 transitions downwardly at a radius of curvature, R8, to a linear section, 78A (Figure 10), which extends downwardly to a radius of curvature, R9, which transitions outwardly to sidewall 16 with a height drop, 78, of 0.125” or 0.188” forming a “dip down” or divider height reduction at the sidewall. The linear section makes an angle of 60° with a horizontal as shown.

Figure 10 is an enlarged view showing the geometry of the height reduction at the sidewall in terminal portion 62. Linear section 78A, makes an angle of 30° with a vertical as shown. Radii of curvature, R8 and R9, have a length within the range of from 0.09” to 0.16" typically 0.125".

Figures 11, 12 and 13 are enlarged details showing variable radii of curvature between the plate bottom and the tall dividers as well as optional variable fillets 36, 38 and 40. Figure 11 shows compartment 28 and dividers 22, 24, as well as optional fillets 36, 38. The variable radii of curvatures, VR, are shown on the diagram. It is seen that the radii of curvature between the plate bottom and sidewalls is constant along medial portion 70 of divider 24 and varies substantially at optional fillets 36, 38.

Figure 12 shows the variable radii of curvature between the plate bottom and the tall dividers around optional variable fillet 38 near the central junction 56 of tall dividers 22, 24 and 26.

Figure 13 shows variable radii of curvature, VR, at fillet 40 at terminal portion 62 of plate between the plate bottom and divider 22. It is seen in Figure 13 that the VR length decreases substantially to the outer portion of divider 22. It is seen in Figures 11 and 13 that variable fillet 36 is aligned with medial portion 70 of divider 24 along direction 24A, while variable fillet 40 is aligned with the junction of divider 22 with the sidewall of the plate at terminal portion 62, along direction 62B.

The variable radii of curvature values shown in Figures 11, 12 and 13 are common to transitions between dividers 22, 24 and 26 and plate bottom 12, as can be appreciated from Figures 1, 2 and 3 and the foregoing discussion.

Figures 14 and 15 illustrate a plate substantially identical to the plate of Figures 1-13, except that the dividers meet at a central junction 56AT in a Y configuration wherein the two layer dividers 24AT and 26AT project outwardly from central junction 56AT to sidewall 16 in an arcuate trajectory as shown. Note the offset from center indicated by the dashed lines.

Dividers 22, 24AT, 26AT transition about central junction 56AT in an arcuate direction change (R4, discussed above), while Dividers 24AT, 26AT and define a radius of curvature RIO as they project to sidewall 16. RIO is suitable 10.188" and may optionally be from 8" to 11" in the design shown. In some designs, R10 may be anywhere from 0.5 to 1.5 times the characteristic plate diameter, preferably from 0.75 to 1.25 times the characteristic plate diameter.

FPI Rigidity is expressed in grams/0.5" deflection and is measured with a Foodservice Packaging Institute Rigidity Tester, available from or through the Foodservice Packaging Institute, Inc., Falls Church, Va., 22043 (www.fpi.org). This test is designed to measure the rigidity (i.e., resistance to buckling and bending) of paper and plastic plates, bowls, dishes, and trays by measuring the force required to deflect the rim of these products a distance of 0.5" while the product is supported at its geometric center. Specifically, the plate specimen is restrained by an adjustable bar on one side and is center supported. The rim or flange side opposite to the restrained side is subjected to 0.5" deflection by means of a motorized cam assembly equipped with a load cell, and the force (grams) is recorded. The test simulates in many respects the performance of a container as it is held in the hand of a consumer, supporting the weight of the container’s contents. A higher FPI value is desirable since this indicates a more rigid product.

Figure 16 is a schematic perspective view of a Foodservice Packaging Institute Rigidity Tester for measuring FPI Rigidity including a test stand generally indicated at 100. A plate, such as compartmented pressware plate 10 is clamped to the test stand with clamping member 110 and positioned on center by posts 120, 130, 140 and 150, with shorter divider 22 aligned with a force transducer probe 160 and clamping member 110 as shown. Posts 140, 150 are removed prior to taking force measurements. This orientation is considered the machine direction (MD). A force transducer measures the force to deflect the flange of the plate 0.5". To measure FPI Rigidity in the cross-direction (CD), the plate is rotated 90°.

FPI Rigidity may also be estimated by finite element analysis (FEA) in both the MD and CD.

Figure 17 is a schematic perspective view of a test apparatus for measuring load to failure capacity for paper plates. A test stand generally indicated at 100(a) includes a clamping assembly 110(a) and a supporting member 150(a). A plate such as plate 10 is positioned, as shown, with the flange of the plate at divider 22 clamped by assembly 110(a) and supported by member 150(a) underneath the plate under the medial portion of divider 22 such that largest compartment 32 is opposite camping assembly 110(a), such that the plate is disposed in its weakest orientation for testing. % lb. weights are added to compartment 32 incrementally until the plate buckles under the load. The test thus provides a simulation of a “one hand hold maximum” of plate 10 and is indicated as a “One Hand Hold-Maximum-Bean Bags” in the examples which follow. Examples

Series of 10.25" circular pressware plates were prepared and tested for FPI Rigidity and Load to Failure (One Hand Hold Maximum). The plates were made from paperboard blanks having a basis weight of 163 lbs/3000 ft ² and 180 lbs/3000 ft ² . The plates tested in Tables 2 and 3 had the outer flange downturn, the variable radii of curvature between the plate bottom and divider sidewalls, the “dip downs” at the terminal portions of the tall dividers at the plate sidewall and the enhanced downturns described above. All of the plates were identical and had the configuration illustrated in connection with Figures 1-13, except as follows: (a) the plates of Tables 4 and 5 had no outer downturn at the periphery of the flange; (b) the plates of Tables 6 and 7 had no enhanced downturn lobes (“dog ears”) and Tables 8 and 9 compare a plate of Figures 1-13 with a substantially identical plate of Figures 14 and 15 having 2 dividers with an arcuate outer trajectory instead of straight dividers as in Figures 1-13.

Details and results of testing appear in Tables 2-7 and Tables 8-9.

10-1/4" Round Compartmented Plate FPI Rigidity and One Hand Hold Maximum Comparisons

Comparing Tables 2 and 3 with Tables 4 and 5, it is seen that the outer downturn at the periphery of the flange had a dramatic, indeed surprising, effect on both FPI Rigidity and One Hand Hold Maximum or Load to Failure. The plates of Tables 4 and 5 without the outer downturn had a geometric mean FPI Rigidity of more than 50% less than corresponding plates of Tables 2 and 3. The plates of Tables 4 and 5 also had Load to Failure values of 20% to 25% less than the plates of Tables 2 and 3; again, a dramatic result.

The plates of Tables 6 and 7, without enhanced downturn lobes, also had lower FPI Rigidity than corresponding plates of Tables 2 and 3, 7% lower GM FPI Rigidity and 13% lower GM FPI Rigidity, respectively. Differences in Load to Failure maximum loads were not readily detectable; that is, were within the same 14 pound load increments measured.

It is seen in Tables 8, 9 below that an arcuate outer trajectory of the larger dividers provides significant improvements to FPI Rigidity and One Hand Hold Maximum for the plates.

FEA Analysis

A plate having the features of Figures 1-13, including divider height reductions at the sidewall or “dip downs” (without pleats) was modeled and analyzed by finite element analysis, FEA (0.014" thickness, 300,000 psi elastic modulus, 0.29 Poisson ratio) to have a FPI Rigidity value of 141 grams. The identical plate, without divider height reductions or “dip downs” was modeled and analyzed by FEA to have an FPI Rigidity Value of 133 grams, or 6% lower than the plate with the ’’dip downs”, all other things being equal.

The FPI Rigidity measurements, the Load to Failure testing and the FEA analysis consistently show that the pressware plates of the invention are unexpectedly superior to plates without the salient features of the inventive compartmented pressware plates.

From the foregoing data, it will be appreciated that the compartmented pressware plates of the invention prepared from a paperboard blank having a basis weight of greater than about from 120 or 150 lbs/3000 ft ² (up to about 300 lbs/3000 ft ² or so) exhibit the following: (a) a One Hand Hold Maximum of at least 1 lb, or at least 1.25 lbs in many cases and (b) an FPI-GM Rigidity of greater than 75 grams, more preferably at least 100 grams, at least 110 grams, at least 115 grams or 120 grams or more.

While circular pressware plates have been described in detail and evaluated for rigidity and strength as above, the inventive plates may be fabricated in a variety of shapes, including square plates, polygonal plates, oval shapes and so forth. Figure 16 is a top isometric view of an octagonal, nominally 10 inch paper pressware plate of the invention having the various features described in connection with Figures 1 to 13, while Figure 17 is a top plan view of the octagonal pressware plate of Figure 16 illustrating the arcuate trajectory of the longer ribs from the central divider junction of the plate to the sidewall of the plate. Corresponding features are numbered 200 numerals higher than in Figures 1-13.

Referring to Figures 18 and 19, there is illustrated an octagonal compartmented pressware plate 210 having a plate bottom 212 defining a plate bottom surface 214 adjoining and transitioning to a plate sidewall 216 extending around bottom 212 and projecting upwardly and outwardly therefrom. The plate profile is based on that disclosed in United States Patent No. 8,177,119 to Litlejohn entitled “Pressed paperboard servingware with arched bottom panel and sharp brim transition”. The plate sidewall defines a plate sidewall surface 218 which adjoins a flange 220 flaring outwardly from sidewall 216. Plate 210 defines 3 tall dividers 222, 224 and 226, divider 222 being of shorter length between compartments 228, 230 and dividers 224, 226 having a longer length between compartments 230, 232 and 228, 232. A central junction 256 is formed by the intersection of dividers 222, 224 and 226. Dividers 224 and 226 extend from central junction 256 to the sidewall in an arcuate trajectory as shown. Pressware plate 210 has optional variable transition radius and fillet features noted in connection with the circular pressware plates 10 described above.

In Figure 20, there is illustrated a flat paperboard blank 300 with a plurality of peripheral scores, P, arranged in clusters around corners of the blank and central spans 310, 320 of the blank to facilitate plating in corresponding areas as the plate is formed. A plurality of central scores, CP spaced inside to the periphery of the blank (and formed plate), is also provided to accommodate pleating about the central junction of the plate and dividers as the pressware is formed. Note that the central scores are arranged in an arcuate trajectory from the center of the Y configuration of CP scores on the blank toward the edge where the sidewall is formed.

Blank 300 is also shaped to accommodate gathering of the paperboard about the central junction and dividers more than other areas of the blank. In this regard, the blank has a first span 314 slightly shorter than a second span 316. The blank transitions between the different edge areas shown by way of fillets characterized by a radius of curvature, R11, of about 3" and an angle of 3° for a nominal 10" plate, while for other size plates, differing transitions may be employed.

Exemplary Embodiments

There is thus provided a variety of embodiments of the present invention, wherein Embodiment No. l is a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom adjoining a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom to a flange flaring outwardly from the sidewall, one or more tall dividers adjoining the plate bottom characterized by a divider height, DH, from the bottom of the plate greater than 9/32", said one or more tall dividers extending from the sidewall to a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, the flange being characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex of the flange, wherein the ratio of V:H is from about 0.1 to about 0.75.

Embodiment No. 2 is a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom defining a bottom surface adjoining and transitioning to a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom, the plate sidewall defining a plate sidewall surface and adjoining a flange flaring outwardly from the sidewall, the plate further comprising one or more tall dividers each having a pair of divider sidewall surfaces and adjoining the plate bottom which transitions to the divider sidewall surfaces, wherein the one or more tall dividers are characterized by a divider height, DH, from the bottom of the plate greater than 9/32", said one or more tall dividers extending from the sidewall toward a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, the flange being characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex of the flange, wherein the ratio of V:H is from about 0.1 to about 0.75, wherein transitions between adjoining surfaces of the bottom surface and the divider sidewall surfaces are characterized by variable radii of curvature wherein the variable radii of curvature vary from a first value proximate to transitions between two surfaces to a second value higher than the first value at transitions proximate to the intersection of three surfaces.

Embodiment No. 3 is the compartmented pressware plate according to Embodiment No.

2, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.25 to 2.5.

Embodiment No. 4 is the compartmented pressware plate according to Embodiment No.

3, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.3 to 2.25. Embodiment No. 5 is the compartmented pressware plate according to Embodiment No. 4, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.35 to 2.1.

Embodiment No. 6 is the compartmented pressware plate according to Embodiment Nos. 2 to 5, wherein the one or more tall dividers have a medial portion between intersections of 3 surfaces wherein the sidewall surfaces of the one or more tall dividers transition from the bottom surface of the plate at a constant medial transition radius of curvature.

Embodiment No. 7 is the compartmented pressware plate according to Embodiment No. 6, wherein the medial transition radius of curvature is from 0.15" to 0.4” or 0.225".

Embodiment No. 8 is the compartmented pressware plate according to Embodiments Nos 2 to 7, wherein one or more regions of the plate proximate to the intersection of 3 surfaces are characterized by a filleted structure having a second value of radius of curvature of from 0.25" to 0.5" between the plate bottom and divider sidewall(s).

Embodiment No. 9 is a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom defining a bottom surface adjoining and transitioning to a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom, the plate sidewall defining a plate sidewall surface and adjoining a flange flaring outwardly from the sidewall, the plate further comprising one or more tall dividers each having a pair of divider sidewall surfaces and adjoining the plate bottom which transitions to the divider sidewall surfaces, wherein the one or more tall dividers are characterized by a divider height, DH, from the bottom of the plate greater than 9/32", said one or more tall dividers extending from the sidewall toward a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, wherein the one or more tall dividers have an outer terminal portion proximate the sidewall and a medial portion between the terminal portion of the one or more tall dividers and the central portion of the plate, the sidewall surfaces of the one or more tall dividers transitioning from the bottom surface of the plate at a constant medial transition radius of curvature over its medial portion, the outer terminal portion of the one or more tall dividers having a filleted structure with variable radii of curvature, including a fillet characteristic radius of curvature between the divider sidewalls and plate bottom larger than the medial radius of curvature of the medial portion of the one or more tall dividers, the flange being further characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex if the flange, wherein the ratio of V:H is from about 0.1 to about 0.75.

Embodiment No. 10 is the compartmented pressware plate according to Embodiment No. 9, wherein the medial transition radius of curvature is from 0.15" to 0.4” or to 0.225”.

Embodiment No. 11 is the compartmented pressware plate according to Embodiment Nos. 8 or 9, wherein the filleted structure of the outer terminal portion of the tall divider includes a first pair of fillets aligned with the medial portion of the one or more tall dividers along the tall divider sidewall surfaces.

Embodiment No. 12 is the compartmented pressware plate according to Embodiment No. 11, wherein the filleted structure of the outer terminal portion of the tall divider includes a second pair of fillets aligned with the outer terminal portion of the one or more tall dividers along the tall divider sidewall surfaces.

Embodiment No. 13 is the compartmented pressware plate according to any one of Embodiments 8 to 12, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.25 to 2.5.

Embodiment No. 14 is the compartmented pressware plate according to Embodiment No.

13, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.3 to 2.25.

Embodiment No. 15 is the compartmented pressware plate according to Embodiment No.

14, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.35 to 2.1.

Embodiment No. 16 is the compartmented pressware plate according to any of Embodiments Nos. 8 to 15, wherein the fillet characteristic radius of curvature is from 0.25” to 0.5”.

Embodiment No. 17 is a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom adjoining a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom to a flange flaring outwardly from the sidewall, one or more tall dividers adjoining the plate bottom characterized by a divider height, DH, from the bottom of the plate greater than 9/32”, said one or more tall dividers extending from the sidewall to a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, the flange being characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex if the flange, wherein the ratio of V:H is from about 0.1 to about 0.75, said one or more dividers also adjoining the sidewall of the plate at a height, SDH, less than DH, wherein the flange is optionally provided with an enhanced downturn in the vicinity of a junction of the one or more dividers with the sidewall, the enhanced downturn having lobes extending downwardly more than adjacent portions of the flange.

Embodiment No. 18 is the compartmented pressware plate according to Embodiment No.

17, wherein the ratio of SDH to DH is from 0.15 to 0.75 .

Embodiment No. 19 is the compartmented pressware plate according to Embodiment No.

18, wherein the ratio of SDH to DH is from 0.25 to 0.65.

Embodiment No. 20 is the compartmented pressware according to Embodiments Nos. 17, 18 or 19, having lobes extending downwardly a distance of from 0.05" to 0.4" more than adjacent portions of the flange.

Embodiment No. 21 is the compartmented pressware according to Embodiments Nos. 17 to 20, wherein the lobes extend downwardly a distance of from 0.1" to 0.35" more than adjacent portions of the flange.

Embodiment No. 22 is the compartmented pressware according to Embodiment No. 21, wherein the lobes extend downwardly a distance of from 0.1" to 0.25" more than adjacent portions of the flange.

Embodiment No. 23 is a compartmented pressware paper plate with tall dividers formed from a paperboard blank comprising a plate bottom defining a bottom surface adjoining and transitioning to a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom, the plate sidewall defining a plate sidewall surface and adjoining a flange flaring outwardly from the sidewall, the plate further comprising one or more tall dividers each having a pair of divider sidewall surfaces and adjoining the plate bottom which transitions to the divider sidewall surfaces, wherein the one or more tall dividers are characterized by a divider height, DH, from the bottom of the plate greater than 9/32", said one or more tall dividers extending from the sidewall toward a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, the flange being characterized by a height, H, at its apex from the plate bottom and an outward flange downturn extending downwardly a distance, V, with respect to the apex if the flange, wherein the ratio of V:H is from about 0.1 to about 0.75, wherein transitions between adjoining surfaces of the bottom surface and the divider sidewall surfaces are characterized by variable radii of curvature wherein the variable radii of curvature vary from a first value proximate to transitions between two surfaces to a second value higher than the first value at transitions proximate to the intersection of three surfaces, said one or more dividers also adjoining the sidewall of the plate at a height, SDH, less than DH, wherein the flange is optionally provided with an enhanced downturn in the vicinity of a junction of the one or more dividers with the sidewall, the enhanced downturn having lobes extending downwardly more than adjacent portions of the flange.

Embodiment No. 24 is the compartmented pressware plate according to Embodiment No.

23, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.25 to 2.5.

Embodiment No. 25 is the compartmented pressware plate according to Embodiment No.

24, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.3 to 2.25.

Embodiment No. 26 is the compartmented pressware plate according to Embodiment No.

25, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.35 to 2.1.

Embodiment No. 27 is the compartmented pressware plate according to Embodiment Nos. 23 to 26, wherein the one or more tall dividers have a medial portion between intersections of 3 surfaces wherein the sidewall surfaces of the one or more tall dividers transition from the bottom surface of the plate at a constant medial transition radius of curvature.

Embodiment No. 28 is the compartmented pressware plate according to Embodiment No. 27, wherein the medial transition radius of curvature is from 0.15" to 0.4".

Embodiment No. 29 is the compartmented pressware plate according to Embodiment Nos. 23 to 28, wherein one or more regions of the plate proximate to the intersection of 3 surfaces is characterized by a filleted structure having a fillet characteristic radius of curvature of from 0.25" to 0.5". Embodiment No. 30 is the compartmented pressware plate according to Embodiment Nos. 23 to 29, wherein the ratio of SDH to DH is from 0.15 to 0.75.

Embodiment No. 31 is the compartmented pressware plate according to Embodiment No. 30, wherein the ratio of SDH to DH is from 0.25 to 0.65 or 0.4.

Embodiment No. 32 is the compartmented pressware plate according to Embodiment Nos. 23 to 31, having lobes extending downwardly a distance of from 0.05" to 0.4" more than adjacent portions of the flange.

Embodiment No. 33 is the compartmented pressware plate according to Embodiment No.

32, wherein the lobes extend downwardly a distance of from 0.1" to 0.35" more than adjacent portions of the flange.

Embodiment No. 34 is the compartmented pressware plate according to Embodiment No.

33, wherein the lobes extend downwardly a distance of from 0.1" to 0.25" more than adjacent portions of the flange.

Embodiment No. 35 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the plate has at least 2 tall dividers.

Embodiment No. 36 is the compartmented pressware plate according to Embodiment No.

35, wherein the plate has 3 tall dividers in a Y configuration at a central junction on the plate.

Embodiment No. 37 is the compartmented pressware plate according to Embodiment No.

36, wherein the central junction transitions between dividers with a radius of curvature of from 0.75" to 1.5".

Embodiment No. 38 is the compartmented pressware plate according to Embodiment Nos. 36 or 37, wherein at least 2 tall dividers have an arcuate trajectory from the central junction on the plate to the sidewall of the plate. The outwardly projecting dividers define a radius of curvature as they project to sidewall. Suitable radii of curvature for the outward trajectory may be anywhere from 0.5 to 1.5 times the characteristic plate diameter, preferably from 0.75 to 1.25 times the characteristic plate diameter.

Embodiment No. 39 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the tall dividers have a divider height, DH, of up to ³ A" . Embodiment No. 40 is the compartmented pressware plate according to Embodiment No. 39, wherein the tall dividers have a divider height, DH, of from about 0.3" to 0.75".

Embodiment No. 41 is the compartmented pressware plate according to Embodiment No. 39, wherein the tall dividers have a divider height, DH, of from about 0.475" to 0.625".

Embodiment No. 42 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the ratio of V:H is from 0.15 to 0.75.

Embodiment No. 43 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the ratio of V:H is from 0.2 to 0.75.

Embodiment No. 44 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the ratio of V:H is from 0.3 to 0.65.

Embodiment No. 45 is the compartmented pressware plate according to Embodiment No. 44, wherein the ratio of V:H is from 0.35 to 0.6.

Embodiment No. 46 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the compartmented pressware plate is circular.

Embodiment No. 47 is the compartmented pressware plate according to any of Embodiment Nos. 1 to 45, wherein the compartmented pressware plate is polygonal.

Embodiment No. 48 is the compartmented pressware plate according to Embodiment No. 47, wherein the compartmented pressware plate is octagonal.

Embodiment No. 49 is the compartmented pressware plate according to Embodiment Nos. 46, 47 or 48, wherein the compartmented pressware plate has a characteristic diameter of from 8" to 12".

Embodiment No. 50 is the compartmented pressware plate according to Embodiment No.

49, wherein the compartmented pressware plate has a characteristic diameter of from 8-1/2" to 11".

Embodiment No. 51 is the compartmented pressware plate according to Embodiment No.

50, wherein the compartmented pressware plate has a characteristic diameter of from 9" to 10- 1/2". Embodiment No. 52 is the compartmented pressware plate according to any of the foregoing Embodiments, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 80 lbs/3000 ft ² to 300 lbs/3000 ft ² .

Embodiment No. 53 is the compartmented pressware plate according Embodiment No.

52, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 145 lbs/3000 ft ² to 240 lbs/3000 ft ² .

Embodiment No. 54 is the compartmented pressware plate according Embodiment No.

53, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 155 lbs/3000 ft ² to 190 lbs/3000 ft ² .

Embodiment No. 55 is a compartmented pressware paper plate with dividers formed from a paperboard blank comprising a plate bottom defining a bottom surface adjoining and transitioning to a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom, the plate sidewall defining a plate sidewall surface and adjoining a flange flaring outwardly from the sidewall, the plate further comprising one or more dividers each having a pair of divider sidewall surfaces and adjoining the plate bottom which transitions to the divider sidewall surfaces, wherein the one or more dividers are characterized by a divider height, DH, from the bottom of the plate, said one or more dividers extending from the sidewall toward a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, wherein transitions between adjoining surfaces of the bottom surface and the divider sidewall surfaces are characterized by variable radii of curvature wherein the variable radii of curvature vary from a first value proximate to transitions between two surfaces to a second value higher than the first value at transitions proximate to the intersection of three surfaces.

Embodiment No. 56 is the compartmented pressware plate according to Embodiment No.

55, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.25 to 2.5.

Embodiment No. 57 is the compartmented pressware plate according to Embodiment No.

56, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.3 to 2.25. Embodiment No. 58 is the compartmented pressware plate according to Embodiment No. 57, wherein the ratio of the second value of variable radii of curvature proximate to the intersection of 3 surfaces to the first value of transitions proximate to transitions between 2 surfaces is from 1.35 to 2.1.

Embodiment No. 59 is the compartmented pressware plate according to Embodiment Nos. 55 to 58, wherein the one or more dividers have a medial portion between intersections of 3 surfaces wherein the sidewall surfaces of the one or more dividers transition from the bottom surface of the plate at a constant medial transition radius of curvature.

Embodiment No. 60 is the compartmented pressware plate according to Embodiment No. 59, wherein the medial transition radius of curvature is from 0.15" to 0.4".

Embodiment No. 61 is the compartmented pressware plate according to Embodiment Nos. 55 to 60, wherein one or more regions of the plate proximate to the intersection of 3 surfaces are characterized by a filleted structure having a second value of radius of curvature of from 0.25" to 0.5" between the plate bottom and divider sidewall(s).

Embodiment No. 62 is the compartmented pressware plate according to Embodiment Nos. 59 to 61, wherein the one or more dividers have an outer terminal portion proximate the sidewall of the plate and between the sidewall of the plate and the medial portion of the divider, the outer terminal portion of the one or more dividers having a filleted structure with variable radii of curvature, including a fillet characteristic radius of curvature between the divider sidewalls and plate bottom larger than the medial radius of curvature of the medial portion of the one or more dividers.

Embodiment No. 63 is the compartmented pressware plate according to Embodiment No.

62, wherein the filleted structure of the outer terminal portion of the divider includes a first pair of fillets aligned with the medial portion of the one or more dividers along the tall divider sidewall surfaces.

Embodiment No. 64 is the compartmented pressware plate according to Embodiment No.

63, wherein the filleted structure of the outer terminal portion of the divider includes a second pair of fillets aligned with the outer terminal portion of the one or more dividers along the divider sidewall surfaces. Embodiment No. 65 is the compartmented pressware plate according to any one of Embodiment Nos. 62 to 64, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.25 to 2.5.

Embodiment No. 66 is the compartmented pressware plate according to Embodiment No.

65, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.3 to 2.25.

Embodiment No. 67 is the compartmented pressware plate according to Embodiment No.

66, wherein the ratio of the fillet characteristic radius of curvature to the medial radius of curvature is from 1.35 to 2.1.

Embodiment No. 68 is the compartmented pressware plate according to any of Embodiment Nos. 62 to 67, wherein the fillet characteristic radius of curvature is from 0.25" to 0.5".

Embodiment No. 69 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 68, wherein said one or more dividers adjoin the sidewall of the plate at a height, SDH, less than DH, wherein the flange is optionally provided with an enhanced downturn in the vicinity of a junction of the one or more dividers with the sidewall, the enhanced downturn having lobes extending downwardly more than adjacent portions of the flange.

Embodiment No. 70 is the compartmented pressware plate according to Embodiment No.

69, wherein the ratio of SDH to DH is from 0.15 to 0.75.

Embodiment No. 71 is the compartmented pressware plate according to Embodiment No.

70, wherein the ratio of SDH to DH is from 0.25 to 0.4 or 0.65.

Embodiment No. 72 is the compartmented pressware according to Embodiment Nos. 69 to 71, having lobes extending downwardly a distance of from 0.05" to 0.4" more than adjacent portions of the flange.

Embodiment No. 73 is the compartmented pressware according to Embodiment No. 72, wherein the lobes extend downwardly a distance of from 0.1" to 0.35" more than adjacent portions of the flange.

Embodiment No. 74 is the compartmented pressware according to Embodiment No. 33, wherein the lobes extend downwardly a distance of from 0.1" to 0.25" more than adjacent portions of the flange. Embodiment No. 75 is a compartmented pressware paper plate with dividers formed from a paperboard blank comprising a plate bottom adjoining a plate sidewall extending around the plate bottom and projecting outwardly and upwardly therefrom to a flange flaring outwardly from the sidewall, one or more dividers adjoining the plate bottom characterized by a divider height, DH, from the bottom of the plate, said one or more dividers extending from the sidewall to a central portion of the plate bottom and being configured to segment the plate bottom into a plurality of serving compartments, said one or more dividers adjoining the sidewall of the plate at a height, SDH, less than DH, wherein the flange is optionally provided with an enhanced downturn in the vicinity of a junction of the one or more dividers with the sidewall, the enhanced downturn having lobes extending downwardly more than adjacent portions of the flange.

Embodiment No. 76 is the compartmented pressware plate according to Embodiment No.

75, wherein the ratio of SDH to DH is from 0.15 to 0.5.

Embodiment No. 77 is the compartmented pressware plate according to Embodiment No.

76, wherein the ratio of SDH to DH is from 0.25 to 0.4.

Embodiment No. 78 is the compartmented pressware plate according to Embodiment Nos. 75, 76 or 79, having lobes extending downwardly a distance of from 0.05" to 0.4" more than adjacent portions of the flange.

Embodiment No. 79 is the compartmented pressware plate according to Embodiment Nos. 75 to 78, wherein the lobes extend downwardly a distance of from 0.1" to 0.35" more than adjacent portions of the flange.

Embodiment No. 80 is the compartmented pressware plate according to Embodiment No. 79, wherein the lobes extend downwardly a distance of from 0.1" to 0.25" more than adjacent portions of the flange.

Embodiment No. 81 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 80, wherein the plate has at least 2 dividers.

Embodiment No. 82 is the compartmented pressware plate according to Embodiment No.

81, wherein the plate has 3 dividers in a Y configuration at a central junction on the plate.

Embodiment No. 83 is the compartmented pressware plate according to Embodiment No.

82, wherein the central junction transitions between dividers with a radius of curvature of from 0.75" to 1.5". Embodiment No. 84 is the compartmented pressware plate according to Embodiment Nos. 82 or 83, wherein at least 2 dividers have an arcuate trajectory from the central junction on the plate to the sidewall of the plate.

Embodiment No. 85 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 84, wherein the dividers have a divider height, DH, of up to V/.

Embodiment No. 86 is the compartmented pressware plate according to Embodiment No.

85, wherein the dividers have a divider height, DH, of from about 0.3" to 0.75".

Embodiment No. 87 is the compartmented pressware plate according to Embodiment No.

86, wherein the tall dividers have a divider height, DH, of from about 0.475" to 0.625".

Embodiment No. 88 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 87, wherein the compartmented pressware plate is circular.

Embodiment No. 89 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 87, wherein the compartmented pressware plate is polygonal.

Embodiment No. 90 is the compartmented pressware plate according to Embodiment No. 89, wherein the compartmented pressware plate is octagonal.

Embodiment No. 91 is the compartmented pressware plate according to Embodiment Nos. 88, 89 or 90, wherein the compartmented pressware plate has a characteristic diameter of from 8" to 12".

Embodiment No. 92 is the compartmented pressware plate according to Embodiment No.

91, wherein the compartmented pressware plate has a characteristic diameter of from 8-1/2" to 11".

Embodiment No. 93 is the compartmented pressware plate according to Embodiment No.

92, wherein the compartmented pressware plate has a characteristic diameter of from 9" to 10- 1/2".

Embodiment No. 94 is the compartmented pressware plate according to any of Embodiment Nos. 55 to 93, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 80 lbs/3000 ft ² to 300 lbs/3000 ft ² . Embodiment No. 95 is the compartmented pressware plate according Embodiment No.

94, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 145 lbs/3OOO ft ² to 240 lbs/3000 ft ² .

Embodiment No. 96 is the compartmented pressware plate according Embodiment No.

95, wherein the compartmented pressware plate is prepared from a paperboard blank having a basis weight of from 155 lbs/3000 ft ² to 190 lbs/3000 ft ² .

While the invention has been described in connection with numerous examples, it will be appreciated by one of skill in the art that plates, bowls, oval platters and trays and so forth having various shapes and sizes may be developed with the inventive characteristics. Some may be square or rectangular with rounded comers, triangular, multi-sided, polygonal and similar shape having the profiles and compartments as described. So also, instead of using a single paperboard layer blank, a composite paperboard blank may be used. For example, a container of the invention may be formed from a composite paperboard material wherein the containers are formed by laminating three separate paperboard layers to one another in the form of the container having the shapes described herein. The particular manipulative steps of forming a composite plate are discussed in greater detail in U.S. Pat. Nos. 6,039,682, 6,186,394 and 6,287,247. In view of the foregoing discussion, relevant knowledge in the art and references discussed above in connection with the foregoing description including the Detailed Description and Background of the Invention, the disclosures of which are all incorporated herein by reference, further description is deemed unnecessary. In addition, it should be understood from the foregoing discussion that aspects of the invention and portions of various embodiments may be combined or interchanged either in whole or in part. Containers of the invention thus provide for increases in FPI Rigidity, as well as an improved ability to support a load. Modifications to the specific embodiments described above, within the spirit and scope of the present invention as is set forth in the appended claims, will be readily apparent to those of skill in the art.