Paperboard bowl products with improved rigidity and moisture barrier properties

Abstract

Aspects of the present disclosure include paperboard bowl products comprising two straight sidewalls parallel to one another in the longitudinal direction of the product, the paperboard bowl products comprising at least one modified starch and at least one crosslinker, wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product, and wherein the paperboard bowl product has a rigidity value ranging from 200 to 500.

Description

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 791,174, filed Apr. 18, 2025, which is incorporated by reference in its entirety.

[0002] The present disclosure is directed to paperboard bowl products with improved rigidity, durability, and moisture barrier properties. More specifically, the disclosure is directed to paperboard bowl products having higher rigidity values, durability, and increased moisture barrier properties compared to conventional paperboard bowl products currently on the market.

[0003] The current disclosure provides methods for increasing rigidity, durability, and moisture barrier properties through geometric design, material engineering, and / or improved processing techniques. In certain embodiments, the paperboard bowl products comprise at least one modified starch and at least one crosslinker.

[0004] Rigidity of a paperboard product generally refers to the measure of resistance of the paperboard product to bending and / or buckling. The Foodservice Packaging Institute (FPI), a trade association that represents the foodservice packaging industry, developed its FPI rigidity test to provide a standard method of measuring the rigidity of paperboard products. FPI rigidity is measured in grams of force required to deflect the rim of a paperboard product by 0.5 inches while the paperboard product is supported at its geometric mean center.

[0005] The rigidity values set forth throughout the present disclosure are determined by measuring the FPI Rigidity value of the paperboard bowl product and dividing that value by the basis weight in pounds / 3000 ft2 ream of the bowl paperboard blank, wherein the bowl paperboard blank has a 6% moisture. Accordingly, the rigidity values set forth in the present disclosure are normalized through this calculation.

[0006] General embodiments of the present disclosure are directed to paperboard bowl products comprising at least one modified starch and at least one crosslinker, wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product, and wherein the paperboard bowl products has a rigidity value ranging from 200 to 800.

[0007] A further embodiment of the present disclosure is directed to a paperboard bowl product comprising amylopectin and at least one crosslinker, wherein the at least one amylopectin is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product, and wherein the paperboard bowl product has a rigidity value ranging from 200 to 800.

[0008] Another embodiment of the present disclosure is directed to an paperboard bowl product comprising a backside additive comprising at least one modified starch and at least one crosslinker, wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product, and wherein the paper board product has a rigidity value ranging from 200 to 800.

[0009] Another embodiments are directed to an paperboard bowl product comprising at least one modified starch and at least one crosslinker, wherein the paperboard bowl product has a circular-shaped outer perimeter and further comprises: a substantially planar bottom region; a frustoconical sidewall extending upward and outward from an outer periphery of the bottom region; an annular inner brim portion contiguous with a radially outer extent of the frustoconical sidewall; and an annular outer frustoconical brim portion contiguous with a radially outer extent of the annular inner brim portion, wherein a first arcuate portion interconnects the bottom region and a radially inner end of the frustoconical sidewall, a second arcuate portion interconnects the radially outer extent of the frustoconical sidewall and the annular inner brim portion, and a third arcuate portion interconnects the radially outer extent of the annular inner brim portion and the annular outer frustoconical brim portion, the annular outer frustoconical brim portion includes a distal concave lip portion around an outer periphery of the product, the frustoconical sidewall extends upward and outward from the bottom region at an angle of 23 ± 1 degree from a vertical line parallel to a central axis of the product, the annular inner brim portion slopes downward and outward from the radially outer extent of the frustoconical sidewall at an angle that is 4 ± 1 degree from a horizontal line parallel to the bottom region, and the annular outer frustoconical brim portion slopes downward more steeply than the downward slope of the annular inner brim portion, extending from the radially outer extent of annular inner brim portion at an angle that is 34 ± 1 degrees from the vertical line parallel to the central axis of the product.

[0010] Another embodiment of the present disclosure is directed to a process for making a rigid paperboard bowl product, the process comprising: a) providing a paperboard material to a die press in a bowl former; b) applying pressure to the bowl former; c) applying a backside coating to the formed bowl using a press coater, wherein the backside coating comprises at least one modified starch in an amount ranging from 2% to 20% by weight of the paperboard bowl product, and at least one crosslinker in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A depicts a die design used to manufacture a bowl in accordance with the present disclosure.

[0012] FIG. 1B depicts another die design used to manufacture a bowl in accordance with the present disclosure.

[0013] FIG. 2 depicts a bowl in accordance with the present disclosure.

[0014] FIG. 3 depicts another bowl in accordance with the present disclosure.

[0015] FIG. 4A depicts a cross-sectional view of the 12-ounce bowl in accordance with the present disclosure.

[0016] FIG. 4B depicts another cross-sectional view of the 12-ounce bowl in accordance with the present disclosure.

[0017] FIG. 5A depicts a cross-sectional view of the 20-ounce bowl in accordance with the present disclosure.

[0018] FIG. 5B depicts another cross-sectional view of the 20-ounce bowl in accordance with the present disclosure.

[0019] FIG. 6 depicts a 32-ounce bowl in accordance with the present disclosure.DETAIL DESCRIPTION

[0020] Embodiments of the present disclosure are directed to paperboard bowl products having improved rigidity. In these embodiments, the rigid paperboard bowl product comprises at least one modified starch and at least one crosslinker, wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product.

[0021] A variety of paperboard bowl products are contemplated in the present disclosure. Non-limiting examples of these paperboard bowl products include 10-ounce bowls, 12-ounce bowls, 20-ounce bowls, 22-ounce bowls, 24-ounce bowls, 32-ounce bowls, and 34-ounce bowls. The bowls can be manufactured in a variety of thicknesses depending on the desired end use and non-limiting examples of the thickness include 10-point, 11-point, 12-point, 13-point, 14-point, 16-point, 18-point, 20-point, 22-point, 24-point, 25-point, and 28-point bowls. In certain embodiments, the bowls have a 13-point thickness, in further embodiments, the bowls have a 20-point thickness and in other embodiments, the bowls have a 22-point thickness. As used herein, paper thickness is measured in thousandths of an inch, referred to as “points,” and a 22-point bowl, for example, will have a thickness equal to 0.022 inches.

[0022] The paperboard bowl products according to the present disclosure can be made using commercially available paper stock. Non-limiting examples include paper stock available from Graphic Packaging International (GPI), such as GPI 20-point Premium bowlstock, which has a target basis weight of 221.5 pounds / 3000 ft2; GPI 24-point bowlstock, which has a target basis weight of 257.0 pounds / 3000 ft2; GPI 18-point, which as a target basis weight of 206.5 pounds / 3000 ft2; and Everest 28-point folding carton board, which has a target basis weight of 303.0 pounds / 3000 ft2. Additional non-limiting, exemplary paper stock includes 14-point, 16-point, 18-point, or 20-point Clearwater paperboard blanks; 14-point, 16-point, 18-point, 20-point, or 22-point WestRock paperboard blanks; and 14-point, 16-point, 18-point, 20-point, or 24-point SAPPI paperboard blanks. In certain embodiments, the basis weight of the paper stock and paperboard blanks range from 120 pounds / 3000 ft2 to 320 pounds / 3000 ft2, such as from 160 pounds / 3000 ft2 to 310 pounds / 3000 ft2, from 180 pounds / 3000 ft2 to 310 pounds / 3000 ft2, from 200 pounds / 3000 ft2 to 310 pounds / 3000 ft2, from 220 pounds / 3000 ft2 to 310 pounds / 3000 ft2, and from 140 pounds / 3000 ft2 to 310 pounds / 3000 ft2.

[0023] According to the present disclosure, the paper stock can be combined with a bleached chemi-thermomechanical pulp (BCTMP). BCTMP is a type of pulp produced through a combination of chemical and mechanical processes in which wood chips, such as hardwood and / or softwood, are subjected to both chemical and thermal treatments. The chemical treatment involves the use of sodium sulfite or sodium bisulfite to break down the lignin in the wood. The thermal treatment involves steaming the wood chips, in order to soften the wood chip and separate the wood fibers. The BCTMP can be added to a conventional paper stock pulp in order to form a homogeneous mixture, or the BCTMP can be added as a separate layer in combination with one or more layers of conventional paperstock. In some embodiments, the BCTMP layers is combined with a single layer of conventional paperstock and in other embodiments, the BCTMP layer is sandwiched between two layers of conventional paperstock.

[0024] In certain embodiments, the final paper blank, paperboard used to make the blank, and / or pulp used to make the paperboard comprises from 5 to 40% by weight BCTMP, such as, for example, from 5 to 35% by weight BCTMP, from 5 to 30% by weight BCTMP, from 5 to 35% by weight BCTMP, from 5 to 20% by weight BCTMP, from 5 to 15% by weight BCTMP, 5 to 10% by weight BCTMP, from 10 to 40% by weight BCTMP, from 10 to 35% by weight BCTMP, from 10 to 30% by weight BCTMP, from 10 to 25% by weight BCTMP, from 10 to 20% by weight BCTMP, from 15 to 40% by weight BCTMP, from 15 to 35% by weight BCTMP, from 15 to 30% by weight BCTMP, from 15 to 25% by weight BCTMP, from 20 to 40% by weight BCTMP, from 20 to 35% by weight BCTMP, from 20 to 30% by weight BCTMP, from 25 to 40% by weight BCTMP, from 25 to 35% by weight BCTMP, and from 30 to 40% by weight BCTMP.

[0025] The paperboard bowl products according to the present disclosure can be press molded from a paper blank or pulp molded from a wet-processed pulp.

[0026] Non-limiting examples of suitable modified starches according to the present disclosure include ethylated starches, amylopectin starches, and combinations thereof. In certain embodiments of the present disclosure, the amylopectin starches are chosen from highly branched amylopectins. Non-limiting examples of suitable modified starches include Ingredion™ PenCote™ L800, Ingredion™ PenCote™ L1000, Ingredion™ Redifilm™5400, Ingredion™ Redifilm™5800, Ingredion™ Redifilm™2030, and EcoSynthetix® EcoSphere®2330. The at least one modified starch can be present in an amount ranging from 2% to 20% dry solids by weight of the paperboard bowl product, and non-limiting exemplary ranges include from 2% to 18% by weight, from 2% to 15% by weight, from 2% to 12% by weight, from 2% to 10% by weight, from 2% to 8% by weight, from 3% to 20% by weight, from 3% to 18% by weight, from 3% to 15% by weight, from 3% to 12% by weight, from 3% to 10% by weight, from 3% to 8% by weight, from 5% to 20% by weight, from 5% to 18% by weight, from 5% to 15% by weight, 5% to 12% by weight, from 5% to 10% by weight, from 5% to 8% by weight, from 7% to 20% by weight, from 7% to 18% by weight, from 7% to 15% by weight, from 7% to 12% by weight, from 7% to 10% by weight, from 10% to 20% by weight, and from 10% to 18% by weight, and from 10% to 15% by weight.

[0027] Non-limiting examples of suitable crosslinkers include glyoxal crosslinkers, potassium zirconium crosslinkers, ammonia zirconium crosslinkers, citric acid crosslinkers, and combinations thereof. In certain embodiments, the amount of glyoxal crosslinkers do not exceed 6% by weight based on the dry weight of the starch content in the paperboard bowl product. Non-limiting, exemplary ranges of the amount of glyoxal crosslinker include from 0.5 to 6% dry weight of the starch, such as 0.5% to 5.5% by weight, 0.5% to 5% by weight, 0.5% to 4.5% by weight, 0.5% to 4% by weight, 0.5% to 3.5% by weight, 0.5% to 3% by weight, 0.5% to 2.5% by weight, 0.5% to 2% by weight, 1% to 5.5% by weight, 1% to 5% by weight, 1% to 4.5% by weight, 1% to 4% by weight, 1% to 3.5% by weight, 1% to 3% by weight, 1% to 2.5% by weight, 1.5% to 5.5% by weight, 1.5% to 5% by weight, 1.5% to 4.5% by weight, 1.5% to 4% by weight, 1.5% to 3.5% by weight, and 1.5% to 3% by weight. In other embodiments, the amount of the at least one zirconium and ammonia crosslinkers does not exceed 5% dry weight of the starch content in the paperboard bowl product. Non-limiting, exemplary ranges of the amount of zirconium and / or ammonia crosslinkers include 0.5% to 4.5% by weight, 0.5% to 4% by weight, 0.5% to 3.5% by weight, 0.5% to 3% by weight, 0.5% to 2.5% by weight, 0.5% to 2% by weight, 0.5% to 1.5% by weight, by weight, 1% to 4.5% by weight, 1% to 4% by weight, 1% to 3.5% by weight, 1% to 3% by weight, 1% to 2.5% by weight, 1% to 2% by weight, 1.5% to 4.5% by weight, 1.5% to 4% by weight, 1.5% to 3.5% by weight, 1.5% to 3% by weight, 1.5% to 2.5% by weight, 2% to 4.5% by weight, 2% to 4% by weight, 2% to 3.5% by weight, 2% to 3% by weight, and 2% to 2.5% by weight. In some embodiments, the amount of the at least one zirconium and ammonia crosslinker does not exceed 2.5% dry weight of the starch content in the paperboard bowl product.

[0028] In certain embodiments of the present disclosure, the paperboard bowl product comprises at least one amylopectin and at least one crosslinker, wherein the at least one amylopectin is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product, and the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product. Non-limiting examples of suitable amylopectins include PenCote™ L800, Redifilm™5800 and EcoSphere® 2330. Non-limiting, exemplary ranges of the amount of at least one amylopectin include from 2% to 18% by weight, from 2% to 15% by weight, from 2% to 12% by weight, from 2% to 10% by weight, from 2% to 8% by weight, from 3% to 20% by weight, from 3% to 18% by weight, from 3% to 15% by weight, from 3% to 12% by weight, from 3% to 10% by weight, from 3% to 8% by weight, from 5% to 20% by weight, from 5% to 18% by weight, from 5% to 15% by weight, 5% to 12% by weight, from 5% to 10% by weight, from 5% to 8% by weight, from 7% to 20% by weight, from 7% to 18% by weight, from 7% to 15% by weight, from 7% to 12% by weight, from 7% to 10% by weight, from 10% to 20% by weight, and from 10% to 18% by weight, and from 10% to 15% by weight. In certain embodiments, the at least one amylopectin is present in an amount ranging from 10 to 20% based on the weight of the paperboard bowl product.

[0029] In further embodiments, the at least one amylopectin and the at least one crosslinker are comprised in one of the following combinations: Ingredion™ PenCote™ L800 and a glyoxal crosslinker; Ingredion™ Redifilm™5800 and a glyoxal crosslinker; EcoSynthetix® EcoSphere®2330 and a glyoxal crosslinker; Ingredion™ PenCote™ L800 and a potassium zirconium crosslinker; Ingredion™ Redifilm™5800 and a potassium zirconium crosslinker; and EcoSynthetix® EcoSphere®2330 and a potassium zirconium crosslinker.

[0030] In certain embodiments, the paperboard bowl products according to the present disclosure have a rigidity value ranging from 200 to 800. Non-limiting, exemplary ranges include rigidity values of 200 to 800, 225 to 800, 250 to 800, 275 to 800, 300 to 800, 325 to 800, 350 to 800, 375 to 800, 400 to 800, 425 to 800, 450 to 800, 475 to 800, 500 to 800, 525 to 800, 550 to 800, 575 to 800, 600 to 800, 625 to 800, 650 to 800, 675 to 800; 200 to 750, 225 to 750, 250 to 750, 275 to 750, 300 to 750, 325 to 750, 350 to 750, 375 to 750, 400 to 750, 425 to 750, 450 to 750, 475 to 750, 500 to 750, 525 to 750, 550 to 750, 575 to 750, 600 to 750, 625 to 750, 650 to 750, 675 to 750; 200 to 700, 225 to 700, 250 to 700, 275 to 700, 300 to 700, 325 to 700, 350 to 700, 375 to 700, 400 to 700, 425 to 700, 450 to 700, 475 to 700, 500 to 700, 525 to 700, 550 to 700, 575 to 700, 600 to 700; 200 to 650, 225 to 650, 250 to 650, 275 to 650, 300 to 650, 325 to 650, 350 to 650, 375 to 650, 400 to 650, 425 to 650, 450 to 650, 475 to 650, 500 to 650, 525 to 650, 550 to 650; 200 to 600, 225 to 600, 250 to 600, 275 to 600, 300 to 600, 325 to 600, 350 to 600, 375 to 600, 400 to 600, 425 to 600, 450 to 600, 475 to 600, 500 to 600; 200 to 550, 225 to 550, 250 to 550, 275 to 550, 300 to 550, 325 to 550, 350 to 550, 375 to 550, 400 to 550, 425 to 550, 450 to 550; and 200 to 500, including 225 to 500, 250 to 500, 275 to 500, 300 to 500, 325 to 500, 350 to 500, 375 to 500, 400 to 500, 425 to 500, 450 to 500, and 475 to 500. In certain embodiments, these rigidity values are produced in paper products formed from 14-point, 15-point, 16-point, 18-point, 20-point, 22-point, and 24-point paper stock. In a further embodiment, the paperboard bowl product had a thickness of 20-point and a rigidity ranging from 400 to 750.

[0031] Additional embodiments of the present disclosure are directed to optimizing backside additive effectiveness. In certain embodiments, the backside additive comprises a combination of at least one modified starch and at least one crosslinker, wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product and the one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard bowl product.

[0032] Non-limiting, exemplary ranges of the amount of at least one modified starch in the backside additive include from 2% to 18% by weight, from 2% to 15% by weight, from 2% to 12% by weight, from 2% to 10% by weight, from 2% to 8% by weight, from 3% to 20% by weight, from 3% to 18% by weight, from 3% to 15% by weight, from 3% to 12% by weight, from 3% to 10% by weight, from 3% to 8% by weight, from 5% to 20% by weight, from 5% to 18% by weight, from 5% to 15% by weight, 5% to 12% by weight, from 5% to 10% by weight, from 5% to 8% by weight, from 7% to 20% by weight, from 7% to 18% by weight, from 7% to 15% by weight, from 7% to 12% by weight, from 7% to 10% by weight, from 10% to 20% by weight, and from 10% to 18% by weight, and from 10% to 15% by weight.

[0033] In these embodiments, the backside additive also comprises at least one crosslinker, and non-limiting examples of suitable crosslinkers include glyoxal crosslinkers, potassium zirconium crosslinkers, ammonia zirconium crosslinkers, citric acid crosslinkers, and combinations thereof. In embodiments wherein the backside additive comprises a glyoxal crosslinker, non-limiting, exemplary ranges of the amount of glyoxal crosslinker include from 0.5 to 6% dry weight of the starch, such as 0.5% to 5.5% by weight, 0.5% to 5% by weight, 0.5% to 4.5% by weight, 0.5% to 4% by weight, 0.5% to 3.5% by weight, 0.5% to 3% by weight, 0.5% to 2.5% by weight, 0.5% to 2% by weight, 1% to 5.5% by weight, 1% to 5% by weight, 1% to 4.5% by weight, 1% to 4% by weight, 1% to 3.5% by weight, 1% to 3% by weight, 1% to 2.5% by weight, 1.5% to 5.5% by weight, 1.5% to 5% by weight, 1.5% to 4.5% by weight, 1.5% to 4% by weight, 1.5% to 3.5% by weight, and 1.5% to 3% by weight. In embodiments when the backside additive comprises at least one zirconium and ammonia crosslinker, non-limiting, exemplary ranges of the amount of zirconium and ammonia crosslinkers include 0.5% to 5% by weight, 0.5% to 4.5% by weight, 0.5% to 4% by weight, 0.5% to 3.5% by weight, 0.5% to 3% by weight, 0.5% to 2.5% by weight, 0.5% to 2% by weight, 0.5% to 1.5%, by weight, 1% to 4.5% by weight, 1% to 4% by weight, 1% to 3.5% by weight, 1% to 3% by weight, 1% to 2.5% by weight, 1% to 2% by weight, 1.5% to 4.5% by weight, 1.5% to 4% by weight, 1.5% to 3.5% by weight, 1.5% to 3% by weight, 1.5% to 2.5% by weight, 2% to 4.5% by weight, 2% to 4% by weight, 2% to 3.5% by weight, 2% to 3% by weight, and 2% to 2.5% by weight.

[0034] In further embodiments, the backside additive comprises one of the following combinations: Ingredion™ PenCote™ L800 and a glyoxal crosslinker; Ingredion™ Redifilm™5800 and a glyoxal crosslinker; EcoSynthetix® EcoSphere®2330 and a glyoxal crosslinker; Ingredion™ PenCote™ L800 and a potassium zirconium crosslinker; Ingredion™ Redifilm™5800 and a potassium zirconium crosslinker; and EcoSynthetix® EcoSphere®2330 and a potassium zirconium crosslinker. It is contemplated that these combinations of modified starches and crosslinkers can be combined in any of the amounts disclosed above.

[0035] In more particular embodiments, the frontside of the paperboard bowl product comprises a clearcoat. Non-limiting examples of clearcoats include water-based clearcoats such as aqueous dispersions of styrene-acrylic copolymers. Non-limiting examples include clearcoats produced by CA Coatings, such as Clear Aquavar™2044DE and Clear Aquavar™2120DE.

[0036] In further embodiments, the frontside of the paperboard bowl product comprises a primer layer and a clearcoat. Non-limiting examples include clearcoats produced by CA Coatings, such as Clear Aquavar™2044DE and Clear Aquavar™ 2120DE. Non-limiting examples include primers produced by CA Coatings, such as Clear Aquavar™2125DE.

[0037] In further embodiments, the paperboard bowl product has a coatings package comprising a backside additive and a frontside clearcoat. In these embodiments, the coated paperboard bowl product comprises one of the following combinations: a backside additive comprising Ingredion™ PenCote™ L800 and a glyoxal crosslinker, and Clear Aquavar™2044DE as the clearcoat; a backside additive comprising Ingredion™ Redifilm™5800 and a glyoxal crosslinker, and Clear Aquavar™2044DE as the clearcoat; a backside additive comprising EcoSynthetix® EcoSphere®2330 and a glyoxal crosslinker, and Clear Aquavar™2044DE as the clearcoat;

[0038] a backside additive comprising Ingredion™ PenCote™ L800 and a potassium zirconium crosslinker, and Clear Aquavar™2120DE as the clearcoat; a backside additive comprising Ingredion™ Redifilm™5800 and a potassium zirconium crosslinker, and Clear Aquavar™2120DE as the clearcoat; and a backside additive comprising EcoSynthetix® EcoSphere®2330 and a potassium zirconium crosslinker, and Clear Aquavar™2120DE as the clearcoat.

[0039] The backside additive according to the present disclosure may also contain additional components that may allow for at least one of higher-solids operations, greater dry rigidity, greater wet rigidity, and higher Consumer Acceptance Scores. Examples of such additional components include surfactants, plasticizers, humectants and combinations thereof.

[0040] Additional embodiments are directed to an paperboard bowl product comprising at least one modified starch and at least one crosslinker, wherein the paperboard bowl product has a circular-shaped outer perimeter and further comprises: a substantially planar bottom region; a frustoconical sidewall extending upward and outward from an outer periphery of the bottom region; an annular inner brim portion contiguous with a radially outer extent of the frustoconical sidewall; and an annular outer frustoconical brim portion contiguous with a radially outer extent of the annular inner brim portion, wherein a first arcuate portion interconnects the bottom region and a radially inner end of the frustoconical sidewall, a second arcuate portion interconnects the radially outer extent of the frustoconical sidewall and the annular inner brim portion, and a third arcuate portion interconnects the radially outer extent of the annular inner brim portion and the annular outer frustoconical brim portion, the annular outer frustoconical brim portion includes a distal concave lip portion around an outer periphery of the product, the frustoconical sidewall extends upward and outward from the bottom region at an angle of 23 ± 1 degree from a vertical line parallel to a central axis of the product, the annular inner brim portion slopes downward and outward from the radially outer extent of the frustoconical sidewall at an angle that is 4 ± 1 degree from a horizontal line parallel to the bottom region, and the annular outer frustoconical brim portion slopes downward more steeply than the downward slope of the annular inner brim portion, extending from the radially outer extent of annular inner brim portion at an angle that is 34 ± 1 degrees from the vertical line parallel to the central axis of the product.

[0041] The terminology “frustoconical” as used herein in connection with the profiles of paperboard bowls or other paperboard products disclosed herein refers to an arcuate surface of rotation profile where it is seen that a sidewall of the container is either curved or frustoconical in shape or composed of combinations of these two shapes. In some cases, a container may be formed by combining portions of several surfaces of rotation as in the case of ovals or other non-circular shapes.

[0042] FIGS. 1A and 1B depict an enlarged cross-sectional profile of portions of exemplary embodiments of dies that may be used in forming the bowls according to the present disclosure. In FIG. 1A, the bottom region and frustoconical sidewall of the bowl may be pressed to a thickness of 0.013 inch (13 pt.) while the annular inner brim portion may be pressed to a thickness of 0.024 inch, and annular outer frustoconical brim portion may be pressed to a thickness of 0.026 inch. In FIG. 1B, the bottom region and frustoconical sidewall of the bowl may be pressed to a thickness of 0.020 inch (20 pt.) while the annular inner brim portion may be pressed to a thickness of 0.025 inch, and annular outer frustoconical brim portion may be pressed to a thickness of 0.026 inch.

[0043] FIGS. 2-5 depict paperboard products in accordance with the present disclosure. The paperboard product may comprise an outer diameter, an inner diameter, a height, a domed center, an evert angle, an evert length, an evert radius of curvature, a brim angle, a brim length, a brim radius of curvature, a sidewall angle, a sidewall length a base diameter, and a sidewall radius of curvature.

[0044] In FIGS. 4A and 4B, the paperboard product depicted is a 12-ounce bowl. In some embodiments, the outer diameter comprises 6.062 inches + / - 0.094 inches, the inner diameter comprises 5.372 inches, a height comprising 1.422 inches, the domed center comprises a radius of curvature of 35.260 inches, the evert angle of 4°+1 / -2°, the evert length of 0.156 inches, the evert radius of curvature of 0.063 inches, the brim length of 0.188 inches, a brim radius of curvature 0.141 inches, a sidewall angle of 23°, a sidewall length of 0.938 inches, a base diameter of 3 inches, a sidewall radius of curvature of 0.750 inches.

[0045] In FIGS. 5A and 5B, the paperboard product depicted is a 20-ounce bowl. In some embodiments, the outer diameter comprises 7.313 inches + / - 0.125 inches, the inner diameter comprises 6.313 inches, a height comprising 1.313 inches, the domed center comprises a radius of curvature of 35.26 inches, the evert angle of 4°+1 / -2°, the evert length of 0.188 inches, the evert radius of curvature of 0.061 inches, the brim length of 0.220 inches, a brim radius of curvature 0.156 inches, a sidewall angle of 21°, a base diameter of 3.219 inches, and a sidewall radius of curvature of 1.000 inch.

[0046] In FIG. 6, the paperboard product depicted is a 32-ounce bowl. In some embodiments, the outer diameter comprises 9.358 inches, a height comprising 1.625 inches, the domed center comprises a radius of curvature of 58.346 inches, the evert angle of 4°+1 / -2°, the evert length of 0.185 inches, the evert radius of curvature of 0.081 inches, the brim length of 0.54 inches, a brim radius of curvature 0.123 inches, a sidewall angle of 22°, an evert angle of 50°, a base diameter of 5.412 inches, a sidewall radius of curvature of 0.750 inches.

[0047] Additional embodiments of the present disclosure are directed to process for making a rigid paperboard product, the process comprising: a) providing a paperboard material to a die press in a bowl former; b) applying pressure to the bowl former; c) applying a backside coating to the formed bowl using a press coater, wherein the backside coating comprises at least one modified starch in an amount ranging from 2% to 20% by weight of the paperboard product, and at least one crosslinker in an amount ranging from 0.5% to 8% by weight based on the dry weight of the starch content in the paperboard product.

Claims

1. A paperboard bowl product comprising at least one modified starch and at least one crosslinker,wherein the at least one modified starch is present in an amount ranging from 2% to 20% by weight of the paperboard bowl product,wherein the at least one crosslinker is present in an amount ranging from 0.5% to 8% by weight based on a dry weight of the starch content in the paperboard bowl product, andwherein the paperboard bowl product has a rigidity value ranging from 200 to 800.

2. The paperboard bowl product according to claim 1, wherein the at least modified starch is a highly branched amylopectin present in an amount ranging from 10 to 20% based on the weight of the paperboard product.

3. The paperboard bowl product according to claim 1, where the at least one crosslinker is chosen from glyoxal crosslinkers, potassium zirconium crosslinkers, ammonia zirconium crosslinkers, citric acid crosslinkers.

4. The paperboard bowl product according to claim 3, wherein the at least one crosslinker is present in an amount ranging from 0.5 to 6% based on the weight of the paperboard product.

5. The paperboard bowl product according to claim 1, wherein the product is a 20-ounce bowl, and wherein the bowl has a thickness ranging from 13 points to 20 points.

6. The paperboard bowl product according to claim 1, wherein the product is a 20-ounce bowl, and wherein the bowl has a thickness ranging from 20 points to 25 points.

7. The paperboard bowl product according to claim 1, wherein the product is a 12-ounce bowl, and wherein the bowl has a thickness ranging from 13 points to 20 points.

8. The paperboard bowl product according to claim 1, wherein the product is a 12-ounce bowl, and wherein the bowl has a thickness ranging from 20 points to 25 points.

9. The paperboard bowl product according to claim 1, wherein the product is a 32-ounce bowl, and wherein the bowl has a thickness ranging from 13 points to 20 points.

10. The paperboard bowl product according to claim 1, wherein the product is a 32-ounce bowl, and wherein the bowl has a thickness ranging from 20 points to 25 points.

11. A paperboard bowl product comprising at least one modified starch and at least one crosslinker, wherein the paperboard bowl product further comprises: a substantially planar bottom region;a substantially frustoconical sidewall extending upward and outward from an outer periphery of the bottom region;an annular inner brim portion contiguous with a radially outer extent of the frustoconical sidewall; andan annular outer frustoconical brim portion contiguous with a radially outer extent of the annular inner brim portion, whereina first arcuate portion interconnects the bottom region and a radially inner end of the frustoconical sidewall, a second arcuate portion interconnects the radially outer extent of the frustoconical sidewall and the annular inner brim portion, and a third arcuate portion interconnects the radially outer extent of the annular inner brim portion and the annular outer frustoconical brim portion,the annular outer frustoconical brim portion includes a distal concave lip portion around an outer periphery of the product,the frustoconical sidewall extends upward and outward from the bottom region at an angle of 23.0 ± 1 degree from a vertical line parallel to a central axis of the product,the annular inner brim portion slopes downward and outward from the radially outer extent of the frustoconical sidewall at an angle that is 4.0 ± 1 degree from a horizontal line parallel to the bottom region, andthe annular outer frustoconical brim portion slopes downward more steeply than the downward slope of the annular inner brim portion, extending from the radially outer extent of annular inner brim portion at an angle that is 34.0 ± 1 degree from the vertical line parallel to the central axis of the product.

12. The paperboard bowl product according to claim 11, wherein the paperboard bowl product has a rigidity value ranging from 200 to 800, as measured by FPI rigidity normalized by basis weight.

13. The paperboard bowl product according to claim 11, wherein the at least one modified starch is a highly branched amylopectin present in an amount ranging from 10% to 20% by weight of the paperboard bowl product.

14. The paperboard bowl product according to claim 11, wherein the at least one crosslinker is selected from the group consisting of glyoxal crosslinkers, potassium zirconium crosslinkers, ammonia zirconium crosslinkers, citric acid crosslinkers, and combinations thereof.

15. The paperboard bowl product according to claim 11, wherein the paperboard bowl product is formed from paperboard having a thickness ranging from 13 points to 25 points.

16. The paperboard bowl product according to claim 11, wherein the paperboard bowl product further comprises a backside additive comprising at least one modified starch and at least one crosslinker.

17. The paperboard bowl product according to claim 11, wherein the paperboard bowl product further comprises a frontside clearcoat located exterior to the primer layer.

18. The paperboard bowl product according to claim 11, wherein the paperboard bowl product is a 12‑ounce bowl.

19. The paperboard bowl product according to claim 11, wherein the paperboard bowl product is a 20-ounce bowl.

20. The paperboard bowl product according to claim 11, wherein the paperboard bowl product is a 32‑ounce bowl.

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