COATED PAPERBOARD CONTAINERS AND METHODS

FIELD

The present disclosure relates to coated paperboard containers and, more particularly, to coated paperboard containers having an aqueous barrier coating disposed over a base barrier coating after precursor paperboard containers are formed with the base barrier coating.

BACKGROUND

Coated paperboard is used in various packaging applications. For example, coated paperboard is used to form cups, pails, cartons, and other containers for holding hot or cold beverages and foodstuff. Coated paperboard is often required to have enhanced barrier properties (e.g., on an interior surface thereof) to provide a barrier against oil, grease, water, and/or moisture vapor and to minimize absorption of liquid. Additionally, many paperboard packages, for example, paperboard cups for food or drink services, also require the paperboard be heat-sealable, making it possible to form cups on a cup machine.

Conventional polyethylene (PE), for example, low-density polyethylene (LDPE), extrusion coated paperboard currently still dominates in such applications by providing both barrier and heat-seal properties. However, conventional extrusion coated paperboard has difficulties in repulping due to difficulty of breaking down the polyethylene film during the repulping process and, thus, are not easily recyclable, causing environmental concerns. As such, there are increasing demands for alternative solutions including new coating technologies to replace extrusion coated paperboard cups.

Repulpable aqueous coatings are one of the promising solutions to address this need. However, the use of repulpable aqueous coatings has presented challenges with regards to the integrity of the coatings when shaping, or forming, a coated paperboard bottom blank for use in a coated paperboard container.

Accordingly, those skilled in the art continue with research and development in the field of coated paperboard containers.

SUMMARY

Disclosed are a coated paperboard container and a method of making a coated paperboard container. The following is a non-exhaustive list of examples, which may or may not be claimed, of the subject matter according to the present disclosure.

In an example, the disclosed coated paperboard container includes a precursor paperboard container that includes a paperboard substrate and a barrier coating on the paperboard substrate. The coated paperboard container also includes and an aqueous barrier coating on at least a portion of the barrier coating after formation of the paperboard substrate, having the barrier coating, into the precursor paperboard container.

In an example, the disclosed coated paperboard container includes a sidewall paperboard substrate, including an interior sidewall-surface and a barrier coating on the interior sidewall-surface. The coated paperboard container further includes a bottom paperboard substrate, including an interior bottom surface and the barrier coating on the interior bottom-surface. The coated paperboard container also includes a bottom seam formed between the sidewall paperboard substrate and the bottom paperboard substrate. The coated paperboard container additionally includes an aqueous barrier coating disposed over the barrier coating along the bottom seam.

In an example, the disclosed method of making a coated paperboard container includes steps of: (1) applying a barrier coating to an interior sidewall-surface of a sidewall paperboard substrate; (2) applying the barrier coating to an interior bottom-surface of a bottom paperboard substrate; (3) connecting the sidewall paperboard substrate and the bottom paperboard substrate together to form a tubular structure; and (4) applying an aqueous barrier coating over the barrier coating along a bottom seam of the tubular structure preformed between the sidewall paperboard substrate and the bottom paperboard substrate.

Other examples of the disclosed coated paperboard container and method will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, perspective view of an example of a coated paperboard container;

FIG. 2 is a schematic, cross-sectional view, along section line 2-2, of the coated paperboard container shown in FIG. 1;

FIG. 3 is a schematic, cross-sectional view, along section line 3-3, of the coated paperboard container shown in FIG. 1;

FIG. 4A is a schematic, sectional view of an example of the coated paperboard cup at portion “4” shown in FIG. 2;

FIG. 4B is a schematic, sectional view of an example of the coated paperboard cup at portion “4” shown in FIG. 2;

FIG. 5A is a schematic, sectional view of an example of the coated paperboard cup at portion “5” shown in FIG. 2;

FIG. 5B is a schematic, sectional view of an example of the coated paperboard cup at portion “5” shown in FIG. 2;

FIG. 6 is a schematic, sectional view of an example of the coated paperboard cup at portion “6” shown in FIG. 2;

FIG. 7 is a schematic illustration of an example of a portion of an application machine for applying an aqueous barrier coating; and

FIG. 8 is a schematic illustration of an example of a portion of the application machine for drying the aqueous barrier coating;

FIG. 9A is a photograph of an interior of a test control cup;

FIG. 9B is a photograph of an exterior of a bottom of the test control cup shown in FIG. 9A;

FIG. 10A is a photograph of an interior of a first test specimen cup;

FIG. 10B is a photograph of a bottom exterior of the first test specimen cup shown in FIG. 10A; and

FIG. 11 is a photograph of bottom exteriors of a second test specimen cup, a third test specimen cup, a fourth test specimen cup, and a fifth test specimen cup.

DETAILED DESCRIPTION

The present description relates to coated paperboard containers, such as cups, that include a paperboard substrate, a barrier coating (e.g., a first aqueous barrier coating), and an additional aqueous barrier coating (e.g., a second aqueous barrier coating) disposed over at least a portion of the first barrier coating after formation of a precursor paperboard container.

The present disclosure recognizes that cellulosic structures coated with aqueous barrier coatings are generally considered repulpable and recyclable and, thus, more sustainable. However, paper containers, for example cups, made of aqueous coated paperboard do not perform at the same level as cups made of low-density polyethylene (LDPE) extrusion coated paperboard. One of the technical challenges is that the aqueous coated cup bottom may show cracking, beverage staining, and even leaking along a fold edge of the cup bottom. The aqueous coated paperboard cups also may have insufficient heal seal, especially at a joint of a side seam and/or a bottom seam, resulting in channel leaking or seeping of beverage.

Further, many paperboard containers that have an aqueous barrier coating or even an extrusion coating, can experience problems with liquid or gas penetration, especially when the barrier coating has defects or pinholes. Liquid or gas penetration can compromise structural and/or functional integrity of the paperboard container and/or stain the inner surface of the container. Such staining can show through the outer surface of the container. The structural and staining issues may be exacerbated under conditions of elevated temperature, increased air flow, or when the food or beverage contains aggressive additives or flavor shots.

Referring to FIGS. 1-11, by way of examples, the present disclosure is directed to a coated paperboard container 100. In one or more examples, the coated paperboard container 100 includes a precursor paperboard container 194 (e.g., as shown in FIGS. 7 and 8) that includes a paperboard substrate 102 and a barrier coating 104. The coated paperboard container 100 also includes an aqueous barrier coating 106. The barrier coating 104, which can be heat-sealable, is on the paperboard substrate 102. For example, the barrier coating 104 is disposed (e.g., applied) to the paperboard substrate 102 before formation or conversion of the paperboard substrate 102, having the barrier coating 104, into the precursor paperboard container 194. The aqueous barrier coating 106 is on (e.g., over) at least a portion of the barrier coating 104. For example, the aqueous barrier coating 106 is disposed (e.g., applied) to the paperboard substrate 102 over the barrier coating 104 after formation or conversion of the paperboard substrate 102, having the barrier coating 104, into the precursor paperboard container 194.

As used herein, the term “precursor paperboard container” refers to a paperboard container after a shaping or converting process performed on a coated paperboard substrate, such as by an automated container (e.g., cup) forming machine. In one or more examples, the precursor paperboard container 194 is an example of a traditional coated paperboard container formed of a paperboard substrate with aqueous barrier coating.

In one or more example, the coated paperboard container 100 is manufactured by disposing (e.g., applying) the barrier coating 104, which may also be referred to as a barrier layer, on at least a portion of an interior surface 116 of the coated paperboard container 100 (e.g., an interior surface of the paperboard substrate 102). Generally, the barrier coating 104 is applied to the paperboard substrate 102 before a shaping or converting process of coated paperboard blanks used to form the precursor paperboard container 194 (e.g., by a cup forming machine). However, cracking or degradation of the barrier coating 104 can occur during the shaping or converting process, particularly at bends, folds, joints, and/or seams of the paperboard substrate 102. Such cracking or degradation of the barrier coating 104 can reduce the leak-resistance and/or stain-resistance properties of the precursor paperboard container 194.

In has been discovered that leak-resistance and/or stain-resistance of coated paperboard containers (e.g., the precursor paperboard container 194) is improved by disposing (e.g., applying) the aqueous barrier coating 106, which may also be referred to as an aqueous barrier layer, as an additional barrier coating on at least a portion of the interior surface 116 over the barrier coating 104 after the precursor paperboard container 194 is formed. As such, the aqueous barrier coating 106 is, or may also be referred to as, an aqueous barrier overcoating.

Accordingly, the combination of the barrier coating 104 (e.g., the barrier layer) and the aqueous barrier layer 106 (e.g., the aqueous barrier layer) functions to minimize bottom fold-edge cracking, staining, and/or leaking of the coated paperboard container 100. Therefore, the coated paperboard container 100 manufactured from the paperboard substrate 102, the barrier coating 104, and the aqueous barrier coating 106 may be particularly well-suited for holding hot beverages (e.g., coffee), hot foodstuffs (e.g., soup, French fries, etc.), cold beverages, cold or frozen foodstuffs, bundle wraps, and flexible type packaging.

The examples of the coated paperboard container 100 described herein have excellent performance and properties. As an example, a combination of the barrier coating 104 and the aqueous barrier coating 106 demonstrates improved leak resistance and/or stain resistance as compared to traditional coated paperboard containers. The coated paperboard containers 100 described herein also have excellent repulpability properties. As an example, the barrier coating 104 and the aqueous barrier coating 106 easily break down during repulping and, thus, are more easily repulpable than paperboard containers having a polyethylene (e.g., low-density polyethylene) extrusion coating.

Referring to FIGS. 1-3, in one or more examples, the paperboard substrate 102 includes, or take the form of, a tubular structure 120, having at least one closed end, that includes the interior surface 116 and an exterior surface 118 (e.g., the precursor paperboard container 194). The interior surface 116 forms an interior (e.g., inner) surface of the coated paperboard container 100 and faces an interior of the coated paperboard container 100. The exterior surface 118 forms an exterior (e.g., outer) surface of the coated paperboard container 100 and faces an exterior of the coated paperboard container 100.

In one or more examples, the barrier coating 104 (e.g., as shown in FIGS. 4-6) is on the interior surface 116. The aqueous barrier coating 106 (e.g., as shown in FIGS. 4-6) is disposed over the barrier coating 104 on at least a portion of the interior surface 116 such that the barrier coating 104 is positioned between the interior surface 116 and the aqueous barrier coating 106.

In one or more examples, the barrier coating 104 is applied to the interior surface 116 before formation of the tubular structure 120. The aqueous barrier coating 106 is applied over the barrier coating 104 after formation of the tubular structure 120. In one or more examples, the aqueous barrier coating 106 is sprayed onto at least a portion of the interior surface 116 over the barrier coating 104.

In one or more examples, coated paperboard container 100 (e.g., the tubular structure 120 formed by the paperboard substrate 102) includes a seam 122 (e.g., as shown in FIG. 1). The seam 122 is formed by a connection between different portions of the paperboard substrate 102 when formed or assembled into the tubular structure 120. In one or more examples, coated paperboard container 100 (e.g., the tubular structure 120 formed by the paperboard substrate 102) includes more than one seam 122 (e.g., a bottom seam 132 as shown in FIG. 2 and a sidewall seam 130 as shown in FIG. 3).

In one or more examples, the aqueous barrier coating 106 is disposed over the barrier coating 104 along the seam 122, such as along the bottom seam 132. In one or more examples, the aqueous barrier coating 106 is disposed over the barrier coating 104 along a fold 192 (e.g., as shown in FIGS. 2 and 6) in the paperboard substrate 102, such as a fold used to form the seam 122 (e.g., the bottom seam 132). In one or more examples, the aqueous barrier coating 106 is disposed over the barrier coating 104 on a portion of the interior surface 116 adjacent to the fold 192 and/or the seam 122, such as adjacent or proximate to the bottom seam 132.

In one or more examples, the barrier coating 104 is heat sealable. In one or more examples, when heated, the barrier coating 104 provides an adhesion to other regions of the paperboard substrate 102 with which it contacts. In one or more examples, the seam 122 is heat sealed using the barrier coating 104.

Referring to FIG. 1, in one or more examples, coated paperboard container 100 (e.g., the tubular structure 120 formed by the paperboard substrate 102) includes an upper end 110 and a lower end 112, opposite the upper end 110. In one or more examples, coated paperboard container 100 (e.g., the tubular structure 120 formed by the paperboard substrate 102) includes a sidewall 108 (e.g., a tubular sidewall) and a bottom wall 114, thereby forming an internal volume of the coated paperboard container 100. The sidewall 108 forms an opening into the internal volume at the upper end 110 of the tubular structure 120. The bottom wall 114 is connected to the sidewall 108 at the lower end 112, thereby at least partially enclosing the lower end 112 of the tubular structure 120.

In one or more examples, the bottom wall 114 fully encloses the lower end 112 (e.g., forms an entirely closed lower end). In one or more examples, the bottom wall 114 partially encloses the lower end 112 (e.g., forms a partially closed lower end).

In one or more examples, the sidewall 108 includes a lip 156, such as a rolled lip, at the upper end 110 of the tubular structure 120 (e.g., as shown in FIG. 2). The lip facilitates attachment of a lid (not shown) or the like to the coated paperboard container 100.

Referring to FIGS. 2 and 3, in one or more examples, the sidewall 108 (e.g., shown in FIG. 1) includes, or is formed by, a sidewall paperboard substrate 126. The bottom wall 114 (e.g., shown in FIG. 1) includes, or is formed by, a bottom paperboard substrate 128 (e.g., bottom stock paperboard substrate). The sidewall paperboard substrate 126 and the bottom paperboard substrate 128 are examples of the paperboard substrate 102.

In one or more examples, the sidewall paperboard substrate 126 (e.g., the sidewall 108) includes an interior sidewall-surface 134 and an exterior sidewall-surface 136. The interior sidewall-surface 134 faces an interior of the coated paperboard container 100 (e.g., forms a portion of the interior surface 116). The exterior sidewall-surface 136 faces an exterior of the coated paperboard container 100 (e.g., forms a portion of the exterior surface 118).

In one or more examples, the sidewall paperboard substrate 126 (e.g., the sidewall 108) includes an upper sidewall-end 142 and a lower sidewall-end 144, opposite the upper sidewall-end 142 (e.g., as shown in FIG. 2). In one or more examples, the upper sidewall-end 142 forms the upper end 110 of the coated paperboard container 100 (e.g., as shown in FIG. 1) and the lower sidewall-end 144 forms the lower end 112 of the coated paperboard container 100 (e.g., as shown in FIG. 1). The sidewall paperboard substrate 126 (e.g., the sidewall 108) also includes a first longitudinal sidewall-end 146 and a second longitudinal sidewall-end 148, opposite the first longitudinal sidewall-end 146 (e.g., as shown in FIG. 3).

In one or more examples, the bottom paperboard substrate 128 (e.g., the bottom wall 114) includes an interior bottom-surface 138 and an exterior bottom-surface 140. The interior bottom-surface 138 faces the interior of the coated paperboard container 100 (e.g., forms a portion of the interior surface 116). The exterior bottom-surface 140 faces the exterior of the coated paperboard container 100 (e.g., forms a portion of the exterior surface 118).

In one or more examples, the bottom paperboard substrate 128 (e.g., the bottom wall 114) is connected or coupled to the lower sidewall-end 144 of the sidewall paperboard substrate 126 (e.g., the sidewall 108). In one or more examples, the coated paperboard container 100 includes the bottom seam 132 formed between the sidewall paperboard substrate 126 (e.g., the sidewall 108) and the bottom paperboard substrate 128 (e.g., the bottom wall 114). The bottom seam 132 is an example of one of the seams 122 of the coated paperboard container 100.

In one or more examples, the aqueous barrier coating 106 is disposed over the barrier coating 104 along the bottom seam 132 and/or along the fold 192 (e.g., as shown in FIGS. 2 and 6) in the bottom paperboard substrate 128 that facilitates connection of the bottom paperboard substrate 128 to the sidewall paperboard substrate 126 along the bottom seam 132.

As illustrated in FIG. 3, in one or more examples, the first longitudinal sidewall-end 146 and the second longitudinal sidewall-end 148 are disposed in an overlapping relationship and are connected or otherwise coupled to each other to form the sidewall seam 130. The sidewall seam 130 is an example of one of the seams 122 of the coated paperboard container 100.

In one or more examples, the first longitudinal sidewall-end 146 and the second longitudinal sidewall-end 148 are heat sealed together by way of the barrier coating 104 to form the sidewall seam 130.

In one or more examples, the sidewall paperboard substrate 126 (e.g., the sidewall 108) and the bottom paperboard substrate 128 (e.g., the bottom wall 114) are heat sealed together by way of the barrier coating 104 to form the bottom seam 132.

As illustrated in FIG. 2, in one or more examples, the bottom paperboard substrate 128 (e.g., the bottom wall 114) includes a circumferential portion 154 (e.g., a portion adjacent to a circumferential edge). In one or more examples, the circumferential portion 154 of the bottom paperboard substrate 128 is connected (e.g., heat sealed) to the interior sidewall-surface 134 at the lower sidewall-end 144 to form the bottom seam 132. In examples of the coated paperboard container 100 in which the tubular structure 120 is non-circular, the circumferential portion 154 of the bottom paperboard substrate 128 may be referred to as a peripheral, or perimeter, portion (e.g., a portion adjacent to a peripheral edge).

In one or more examples, the sidewall 108 (e.g., the sidewall paperboard substrate 126) of the coated paperboard container 100 is assembled from a blank (not shown) of a suitable substrate material that has been cut to a desired perimeter shape and wrapped around a mandrel (not shown). The sidewall paperboard substrate 126 includes the barrier coating 104 on the interior sidewall-surface 134. With the blank wrapped around the mandrel, the first longitudinal sidewall-end 146 overlaps the second longitudinal sidewall-end 148. The first longitudinal sidewall-end 146 and the second longitudinal sidewall-end 148 are then connected (e.g., heat sealed) to form the sidewall seam 130. Generally, the sidewall seam 130 extends from the upper sidewall-end 142 to the lower sidewall-end 144.

In one or more examples, the bottom wall 114 (e.g., the bottom paperboard substrate 128) of the coated paperboard container 100 is assembled from a blank (not shown) of a suitable substrate material that has been cut or punched to a desired perimeter shape. The bottom paperboard substrate 128 includes the barrier coating 104 on the interior bottom-surface 138. With the sidewall 108 assembled, the bottom wall 114 is connected (e.g., heat sealed) to the lower sidewall-end 144 to form the bottom seam 132. Generally, the bottom seam 132 extends along a circumference (or a perimeter) of the bottom wall 114 and the lower sidewall-end 144.

As used herein, the term “suitable substrate” includes any manner of foldable sheet material capable of being coated with the barrier coating 104 and the aqueous barrier coating 106. In one or more examples, the suitable substrate is, or includes, a cellulosic material or cellulosic substrate. The paperboard substrate 102 may be bleached or unbleached. Examples, of the paperboard substrate 102 include, but are not limited to, a solid bleached sulfate (SBS) substrate, an uncoated natural kraft (UNK) substrate, an uncoated recycled board (URB) substrate, or an uncoated folding boxboard (FBB) substrate. The paperboard substrate may be formed from virgin fibers, recycled fibers, or combinations thereof

In one or more examples, the sidewall seam 130 is heat sealed by way of (e.g., using) the barrier coating 104 to connect the first longitudinal sidewall-end 146 and the second longitudinal sidewall-end 148 together. In one or more examples, the barrier coating 104 on the interior sidewall-surface 134 at the first longitudinal sidewall-end 146 is heat sealed to the exterior sidewall-surface 136 at the second longitudinal sidewall-end 148 to form the sidewall seam 130. In one or more examples, the barrier coating 104 on the interior sidewall-surface 134 at the first longitudinal sidewall-end 146 is heat sealed to an exterior barrier coating 162 (e.g., as shown in FIG. 4A) on the exterior sidewall-surface 136 at the second longitudinal sidewall-end 148 to form the sidewall seam 130.

In one or more examples, the bottom seam 132 is heat sealed by way of (e.g., using) the barrier coating 104 to connect the sidewall paperboard substrate 126 and the bottom paperboard substrate 128 together. In one or more examples, the circumferential portion 154 of the bottom paperboard substrate 128 and the lower sidewall-end 144 are disposed in an overlapping relationship and are connected or coupled (e.g., heat sealed) to each other to form the bottom seam 132.

As illustrated in FIG. 2, in one or more examples, the lower sidewall-end 144 of the sidewall paperboard substrate 126 is folded towards the interior of coated paperboard container 100 to form a folded edge 158 defining a circumferential recess 150. The circumferential portion 154 of the bottom paperboard substrate 128 is folded towards the exterior bottom-surface 140 (e.g., along the fold 192) to form a circumferential lip 152. The circumferential lip 152 is received in the circumferential recess 150 and is connected or coupled (e.g., heat sealed) to the folded edge 158 of the lower sidewall-end 144.

In one or more examples, the barrier coating 104 on the interior sidewall-surface 134 at the lower sidewall-end 144 (e.g., of the folded edge 158) is heat sealed to the barrier coating 104 on the interior bottom-surface 138 at the circumferential lip 152 to form the bottom seam 132. In one or more examples, the barrier coating 104 on the interior sidewall-surface 134 at the lower sidewall-end 144 (e.g., of the folded edge 158) is heat sealed to the exterior barrier coating 162 (e.g., as shown in FIG. 6) or an exterior non-barrier coating 160 (e.g., as shown in FIG. 5B) of the exterior bottom-surface 140 at the circumferential lip 152 to form the bottom seam 132.

In other examples, different configurations of the connection between the sidewall paperboard substrate 126 and the bottom paperboard substrate 128 are contemplated. As such, the examples of the connection between bottom paperboard substrate 128 and the sidewall paperboard substrate 126 are not meant to imply structural limitations with respect any one of the illustrative examples.

Referring to FIGS. 4A and 4B, in one or more examples, the sidewall 108 includes the barrier coating 104 disposed on the sidewall paperboard substrate 126 and the aqueous barrier coating 106 disposed on at least a portion of the sidewall paperboard substrate 126 over the barrier coating 104. In one or more examples, the barrier coating 104 (e.g., a sidewall barrier coating) is disposed on the interior sidewall-surface 134, such as substantially an entirety of the interior sidewall-surface 134. In one or more examples, the aqueous barrier coating 106 is disposed on (e.g., over) the barrier coating 104 of at least a portion of the interior sidewall-surface 134 adjacent to the bottom seam 132.

Referring to FIGS. 5A and 5B, in one or more examples, the bottom wall 114 includes the barrier coating 104 disposed on the bottom paperboard substrate 128 and the aqueous barrier coating 106 disposed on at least a portion of the bottom paperboard substrate 128 over the barrier coating 104. In one or more examples, the barrier coating 104 (e.g., bottom barrier coating) is disposed on the interior bottom-surface 138, such as substantially an entirety of the interior bottom-surface 138. In one or more examples, the aqueous barrier coating 106 is disposed on (e.g., over) the barrier coating 104 of at least a portion of the interior bottom-surface 138 adjacent to the bottom seam 132.

In one or more examples, the barrier coating 104 (e.g., a sidewall barrier coating) is applied to the interior sidewall-surface 134 of the sidewall paperboard substrate 126 and the barrier coating 104 (e.g., a bottom barrier coating) is applied to the interior bottom-surface 138 of the bottom paperboard substrate 128 before formation of the tubular structure 120. The aqueous barrier coating 106 is applied over the barrier coating 104 after formation, or assembly, of the tubular structure 120.

Referring to FIGS. 4A, 4B, 5A, and 5B, in one or more examples, the coated paperboard container 100 includes an exterior barrier coating 162 disposed on the exterior surface 118 of the paperboard substrate 102. In these examples, the exterior barrier coating 162 forms the exposed, exterior surface of the coated paperboard container 100. As illustrated in FIGS. 4A and 4B, in one or more examples, the exterior barrier coating 162 (e.g., exterior sidewall barrier coating) is disposed on the exterior sidewall-surface 136, such as substantially an entirety of the exterior sidewall-surface 136, of the sidewall paperboard substrate 126. As illustrated in FIGS. 5A and 5B, in one or more examples, the exterior barrier coating 162 (e.g., exterior bottom barrier coating) is disposed on the exterior bottom-surface 140, such as substantially an entirety of the exterior bottom-surface 140, of the bottom paperboard substrate 128.

In one or more examples, the barrier coating 104 and the exterior barrier coating 162 are substantially the same. For example, the barrier coating 104 and the exterior barrier coating 162 consist essentially of the same constituent materials. In such examples, the barrier coating 104 may also be referred to as an interior barrier coating.

Optionally, as illustrated in FIGS. 4B and 5B, in one or more examples, the coated paperboard container 100 includes a non-barrier coating 160 disposed on (e.g., over) the exterior barrier coating 162 on the exterior surface 118 of the paperboard substrate 102. In these examples, the non-barrier coating 160 forms the exposed, exterior surface of the coated paperboard container 100. As illustrated in FIG. 4B, in one or more examples, the non-barrier coating 160 is disposed on (e.g., over) the exterior barrier coating 162 on the exterior sidewall-surface 136. As illustrated in FIG. 5B, in one or more examples, non-barrier coating 160 is disposed on (e.g., over) the exterior barrier coating 162 on the exterior bottom-surface 140.

Alternatively, in one or more examples, the coated paperboard container 100 includes the non-barrier coating 160 disposed on the exterior surface 118 of the paperboard substrate 102. In these examples, the non-barrier coating 160 forms the exposed, exterior surface of the coated paperboard container 100. In one or more examples, the non-barrier coating 160 is disposed on the exterior sidewall surface 136. In one or more examples, the non-barrier coating 160 is disposed on the exterior bottom-surface 140.

In one or more examples, the exterior barrier coating 162 (e.g., exterior sidewall barrier coating) and/or the non-barrier coating 160 (e.g., sidewall non-barrier coating) are applied to the exterior sidewall-surface 136 of the sidewall paperboard substrate 126 and the exterior barrier coating 162 (e.g., exterior bottom barrier coating) and/or the non-barrier coating 160 (e.g., bottom non-barrier coating) are applied to the exterior bottom-surface 140 of the bottom paperboard substrate 128 before formation of the tubular structure 120.

In other examples, various additional or alternative coating layers, either barrier or non-barrier, may be incorporated into the coated paperboard container 100 (e.g., applied to the interior surface 116 and/or the exterior surface 118 of the paperboard substrate 102) without departing from the scope of the present disclosure.

Referring to FIG. 6, the paperboard substrate 102 may develop cracks 164 (e.g., microcracks) in the barrier coating 104 during formation of the coated paperboard container 100. For example, cracks 164 may develop in the barrier coating 104 on the interior bottom-surface 138 of the bottom paperboard substrate 128 and, more particularly, at the fold 192 (e.g., an edge-folded portion) during formation of the bottom wall 114 and/or along the bottom seam 132 during connection of the bottom wall 114 to the sidewall 108. Such cracks 164 may enable liquid to penetrate through the barrier coating 104. Application of the aqueous barrier coating 106 over the barrier coating 104, such as along the fold 192 and/or the bottom seam 132 and. optionally, on at least a portion of the interior sidewall-surface 134 and interior bottom-surface 138, covers the cracks 164 and prevents liquid from penetrating the barrier coating 104 and, thus, improves the stain resistance and leak-resistance of the coated paperboard container 100.

The aqueous barrier coating 106 includes any suitable material composition. In one or more examples, the aqueous barrier coating 106 includes a polymer material. In one or more examples, the aqueous barrier coating 106 includes or is acrylic. In one or more examples, the aqueous barrier coating 106 includes or is styrene acrylate. In one or more examples, the aqueous barrier coating 106 styrene butadiene. In one or more examples, the aqueous barrier coating 106 includes or is ethylene acrylic acid. In one or more examples, the aqueous barrier coating 106 includes or is polyvinyl acrylic. In one or more examples, the aqueous barrier coating 106 includes or is polyolefin. In one or more examples, the aqueous barrier coating 106 includes or is polyester. In one or more examples, the aqueous barrier coating 106 includes or is polylactic acid. In one or more examples, the aqueous barrier coating 106 includes or is polyhydroxy alkanoate. In one or more examples, the aqueous barrier coating 106 includes or is epoxy. In one or more examples, the aqueous barrier coating 106 includes or is polyurethane.

In one or more examples, the aqueous barrier coating 106 includes at least one of acrylic, styrene acrylate, styrene butadiene, ethylene acrylic acid, polyvinyl acrylic, polyolefin, polyester, polylactic acid, polyhydroxy alkanoate, epoxy, and polyurethane.

In one or more examples, the aqueous barrier coating 106 is applied to the paperboard substrate 102 at various area densities. In one or more examples, the aqueous barrier coating 106 has an area density of approximately 2 grams per square meter (g/m2) to approximately 20 grams per square meter. In one or more examples, the aqueous barrier coating 106 has an area density of approximately 3 grams per square meter to approximately 18 grams per square meter. In one or more examples, the aqueous barrier coating 106 has an area density of approximately 5 grams per square meter to approximately 15 grams per square meter. In one or more examples, the aqueous barrier coating 106 has an area density of approximately 8 grams per square meter to approximately 12 grams per square meter.

In one or more examples, the aqueous barrier coating 106 is applied to the paperboard substrate 102 at various coat weights (e.g., on a dry basis). In one or more examples, the aqueous barrier coating 106 has coat weight of approximately 0.03 grams per container to approximately 0.3 grams per container. In one or more examples, the aqueous barrier coating 106 has coat weight of approximately 0.06 grams per container to approximately 0.2 grams per container. In one or more examples, the aqueous barrier coating 106 has coat weight of approximately 0.10 grams per container to approximately 0.15 grams per container.

In one or more examples, the barrier coating 104 and the aqueous barrier coating 106 are substantially the same. For example, the barrier coating 104 and the aqueous barrier coating 106 consist essentially of the same constituent materials. In such examples, the barrier coating 104 may be referred to as a first aqueous barrier coating, as an aqueous barrier undercoating, or an aqueous barrier base coating, and the aqueous barrier coating 106 may be referred to as a second aqueous barrier coating or as an aqueous barrier overcoating.

In one or more examples, the barrier coating 104 and the aqueous barrier coating 106 are different. For example, the barrier coating 104 and the aqueous barrier coating 106 consist essentially of the different constituent materials.

As illustrated in FIGS. 1-3 and 6-10, in one or more examples, the coated paperboard container 100 is, or takes the form of, a cup 124 (e.g., 8-ounce, 12-ounce, 16-ounce, 24-ounce, etc. disposable cup) having a frustoconical shape. In one or more examples, the coated paperboard container 100 (e.g., the cup 124) is configured to hold hot beverages, cold beverage, hot foodstuff, or cold foodstuff.

While the illustrative examples show the coated paperboard container 100 in the form of the cup 124, in other examples, the coated paperboard container 100 may take the form of any one of various other types of containers having a generally tubular structure of various shapes, sizes, and/or configurations with at least one (e.g., partially or entirely) closed end, such as cartons, pails (e.g., for French-fried potatoes), boxes, trays, and the like, which are used for various types of hot or cold food or beverage products in which improved leak resistance and/or stain resistance is beneficial.

By way of examples, the present disclosure is also directed to a method of making the coated paperboard container 100.

In one or more examples, the method includes a step of applying the barrier coating 104 (e.g., the sidewall barrier coating) to the interior sidewall-surface 134 of the sidewall paperboard substrate 126. The method includes a step of applying the barrier coating 104 (e.g., the bottom barrier coating) to the interior bottom-surface 138 of the bottom paperboard substrate 128. In one or more examples, the method includes a step of connected the sidewall paperboard substrate 126 and the bottom paperboard substrate 128 together to form the tubular structure 120. The method includes a step of applying the aqueous barrier coating 106 over the barrier coating 104 along the bottom seam 132 of the tubular structure 120 formed between the sidewall paperboard substrate 126 and the bottom paperboard substrate 128.

In one or more examples, the step of applying the aqueous barrier coating 106 includes a step of spraying the aqueous barrier coating 106 on the barrier coating 104 along the bottom seam 132 of the tubular structure 120. In one or more examples, the step of applying the aqueous barrier coating 106 also includes a step of drying the aqueous barrier coating 106.

In one or more examples, the step of connected the sidewall paperboard substrate 126 and the bottom paperboard substrate 128 together includes a step of heat sealing the sidewall paperboard substrate 126 and the bottom paperboard substrate 128 together by way of the barrier coating 104.

In one or more examples, the method includes a step of applying the aqueous barrier coating 106 over the barrier coating 104 on at least a portion of the interior sidewall-surface 134 adjacent to the bottom seam 132.

Referring to FIGS. 7 and 8, in one or more examples, the aqueous barrier coating 106 is applied using an application machine 174. In one or more examples, the application machine 174 includes a sprayer 166 configured to spray the aqueous barrier coating 106 onto at least a portion of the interior surface 116 of the paperboard substrate 102 of the precursor paperboard container 194 over the barrier coating 104, as illustrated in FIG. 7. In one or more examples, the application machine 174 includes a dryer 176 configured to dry the aqueous barrier coating 106, applied to the interior surface 116 over the barrier coating 104, as illustrated in FIG. 8.

As illustrated in FIG. 7, in one or more examples, the sprayer 166 includes a nozzle 168. The nozzle 168 is configured to dispense a spray 184 of a liquid aqueous barrier 172. The nozzle 168 is configured to generate the spray 184 having any suitable spray pattern sufficient to coat at least a portion of the interior surface 116, such as along the fold 192 and/or the bottom seam 132, at least a portion of the interior sidewall-surface 134, and at least a portion of the interior bottom-surface 138, with the liquid aqueous barrier 172 to form the aqueous barrier coating 106 over the barrier coating 104.

In one or more examples, the nozzle 168 is movable relative to the precursor paperboard container 194 (e.g., in the directions of arrow 190) during application of the liquid aqueous barrier 172. In one or more examples, the nozzle 168 is brought into an indexed relationship with the open end of the precursor paperboard container 194 so that a configured spray pattern of the spray 184 can be directed against the interior surface 116. For example, the nozzle 168 is configured to move toward or away from the bottom wall 114 of the coated paperboard container 100 to enable suitable coverage of the spray 184.

In one or more examples, the sprayer 166 also includes other components common to spray application mechanisms, such as, but not limited to, a pump 178 and a supply 170 of the liquid aqueous barrier 172.

As illustrated in FIG. 8, in one or more examples, the dryer 176 includes a fan 180. The fan 180 is configured to generate an airstream 186 that is directed toward the interior surface 116 of the coated paperboard container 100 to dry the liquid aqueous barrier 172, applied by the sprayer 166. In one or more examples, the dryer 176 also includes a heating element 182 configured to heat the airstream 186 to a temperature suitable to dry the liquid aqueous barrier 172.

In one or more examples, the application machine 174 includes a container holder 188. The container holder 188 is configured to secure the precursor paperboard container 194 (and the coated paperboard container 100), such as at the lower end 112, during spray application and drying of the aqueous barrier coating 106. In one or more examples, the container holder 188 is also configured to rotate the precursor paperboard container 194 relative to the sprayer 166 and/or the dryer 176 during spray application and/or drying of the aqueous barrier coating 106. In one or more examples, rotation of the coated paperboard container 100 urges the liquid aqueous barrier 172 toward the fold 192 and/or the bottom seam 132.

Referring now to FIGS. 9-11, experiments were conducted to evaluate the use of an aqueous barrier overcoating (e.g., the aqueous barrier coating 106) disposed over an aqueous barrier undercoating, or base coating, (e.g., the barrier coating 104) on an interior surface of a paperboard cup. The paperboard cups used in the experiments were made on a Paper Machinery Corporation (PMC) cup machine, model PMC-1250.

The sidewall paperboard substrate, forming the sidewall of each cup, was solid bleached sulfate (SBS) paperboard (e.g., cupstock) substrate having 18-point caliper thickness and 185 pounds per 3000 square feet basis weight, manufactured by WestRock Company of Atlanta, Ga. A felt side of the sidewall paperboard substrate was coated with two-layers of a heat-sealable barrier coating (e.g., two layers of the barrier coating 104). The total coat weight of the two-layers of the heat-sealable barrier coating (e.g., the barrier coating 104) was 11.9 pounds per 3000 square feet.

The bottom paperboard substrate, forming the bottom wall of each cup, was solid bleached sulfate (SBS) paperboard (e.g., cupstock) substrate having 13-point caliper thickness and 150 pounds per 3000 square feet basis weight, manufactured by WestRock Company. A felt side of the bottom paperboard substrate was coated with two-layers of a heat-sealable barrier coating (e.g., two layers of the barrier coating 104). The total coat weight of the two-layers of the heat-sealable barrier coating (e.g., the barrier coating 104) was 11.6 pounds per 3000 square feet.

The felt side of the sidewall paperboard substrate of all the test cups was coated with the two-layers of the heat-sealable barrier coating (e.g., the barrier coating 104) using a blade coater and subsequently a rod coater. The felt side of the bottom paperboard substrate of all of the test cups was coated with the two-layers of the heat-sealable barrier coating (e.g., the barrier coating 104) using a blade coater. The felt side of the sidewall paperboard substrate and the bottom paperboard substrate corresponds to the interior of the cup.

The formulation of the heat-sealable barrier coating (e.g., the barrier coating 104) applied to the sidewall paperboard substrate and the bottom paperboard substrate consisted essentially of: HYDROCARB® 60, Omya AG of Oftringen; BARRISURF® XP, IMERYS Kaolin; and CARTASEAL® SCR, Archroma, at a ratio of 65/35/250 by weight.

The sidewall of each cup was formed (e.g., assembled) by heat sealing the sidewall paperboard substrate to itself, by way of the heat-sealable barrier coating (e.g., the barrier coating 104), to form a sidewall seam. The bottom wall of each cup was formed from the bottom paperboard substrate using a cylindrical punch head with a rounded leading-edge radius of 5/32 inch. A circumferential lip of the bottom wall was heat sealed to the sidewall, by way of the heat-sealable barrier coating (e.g., the barrier coating 104), to form a bottom seam.

The test cups used in the experiment were made as described above. The test cups were separated into two groups, a test control group and a test specimen group. The cups of the test control group, referred to herein as control cups, had the two-layers of the heat-sealable barrier coating (e.g., the barrier coating 104) applied to the interior surface, as described above. The cups of the test specimen group, referred to herein as specimen cups, also included an additional aqueous barrier coating (e.g., the aqueous barrier coating 106) applied to at least a portion of the interior surface over the heat-sealable barrier coating (e.g., the barrier coating 104) after the cups were formed.

A first specimen cup (idented as SC-1) was spray coated with an aqueous barrier coating (e.g., the aqueous barrier coating 106) of RHOBARR™ 320 polyolefin dispersion, The Dow Chemical Corporation. The aqueous barrier coating of RHOBARR™ 320 polyolefin dispersion was diluted to a range of approximately 20% to approximately 15% to make a fine-mist spray. The aqueous barrier coating of RHOBARR™ 320 polyolefin dispersion was spray-applied at a rate of approximately 0.14 gram dry coating per cup, which was estimated at approximately 11 gram per square meter of coated area. The aqueous barrier coating of RHOBARR™ 320 polyolefin dispersion was spay-applied over the heat-sealable barrier coating to the bottom seam, at least a portion of the interior sidewall surface and at least a portion of the interior bottom surface of the cup.

A second specimen cup (idented as SC-2), a third specimen cup (identified as SC-3), a fourth specimen cup (identified as SC-4), and a fifth specimen cup (identified as SC-5) were each spray coated with an aqueous barrier coating (e.g., the aqueous barrier coating 106) of CARTASEAL® SCR, Archroma. The aqueous barrier coating of CARTASEAL® SCR was diluted with water to a solids content of approximately 33%. The aqueous barrier coating of CARTASEAL® SCR was spay-applied over the heat-sealable barrier coating to the bottom seam, at least a portion of the interior sidewall surface and at least a portion of the interior bottom surface of the cup.

The second specimen cup (SC-2) was sprayed with 1 pulse of the aqueous barrier coating of CARTASEAL® SCR. The aqueous barrier coating of CARTASEAL® SCR was spray-applied at a rate of approximately 0.25 gram dry coating per cup, which was estimated at approximately 20 gram per square meter of coated area.

The third specimen cup (SC-3) was sprayed with 1 pulse of the aqueous barrier coating of CARTASEAL® SCR. The aqueous barrier coating of CARTASEAL® SCR was spray-applied at a rate of approximately 0.13 gram dry coating per cup, which was estimated at approximately 10 gram per square meter of coated area.

The fourth specimen cup (SC-4) was sprayed with 2 pulses of the aqueous barrier coating of CARTASEAL® SCR. The aqueous barrier coating of CARTASEAL® SCR was spray-applied at a rate of approximately 0.21 gram dry coating per cup, which was estimated at approximately 16 gram per square meter of coated area.

The fifth specimen cup (SC-5) was sprayed with 2 pulses of the aqueous barrier coating of CARTASEAL® SCR. The aqueous barrier coating of CARTASEAL® SCR was spray-applied at a rate of approximately 0.18 gram dry coating per cup, which was estimated at approximately 14 gram per square meter of coated area.

The test cups, including a control cup (idented as CC), the first specimen cup (SC-1), the second specimen cup (SC-2), the third specimen cup (SC-3), the fourth specimen cup (SC-4), and the fifth specimen cup (SC-5) were evaluated for coffee holdout. The coffee used for cup testing was prepared by brewing Starbucks medium house blend ground coffee at a ratio of 36 grams (g) of coffee powder per 1100 milliliters (mL) of distilled water. The coffee was set at a temperature of 90° C. 37 milliliters of Rich's non-dairy creamer were then added and mixed with the coffee. The mixture of coffee and creamer was then poured into each one of the test cups to a level 10 millimeters (mm) below the rim of the cup. After a 30-minute hold, the mixture of coffee and creamer was removed from the cups and the cups were rinsed with distilled water. The empty cups were then immediately evaluated for leakage, staining, and/or damage.

As illustrated in FIGS. 9-11, photographs were taken of the test cups following the coffee holdout evaluation described above. As shown in FIGS. 9A and 9B, the control cup (CC) exhibited significant coffee staining (e.g., multiple coffee stains) along the fold and bottom seam on the interior of the cup, on the interior sidewall-surface proximate (e.g., at or near) the bottom seam, on the interior bottom-surface proximate the bottom seam, and on the exterior bottom-surface proximate the bottom seam. As shown in FIGS. 10 and 11, the specimen cups (SC-1 in FIGS. 10A and 10B; and SC-2, SC-3, SC-4, and SC-5 in FIG. 11) exhibited very minor coffee staining along the fold and bottom seam on the interior of the cup and no visible coffee staining on the interior sidewall-surface proximate (e.g., at or near) the bottom seam, on the interior bottom-surface proximate the bottom seam, or on the exterior bottom-surface proximate the bottom seam. FIGS. 10A, 10B and 11, taken together, demonstrate that the additional aqueous barrier coating (e.g., the aqueous barrier coating 106) applied over the aqueous barrier base coating (e.g., the barrier coating 104) significantly reduces the amount of internal and external staining along and proximate the bottom seam of the cup.

In one or more examples, the paperboard substrate 102 include any web of fibrous material that is capable of being coated with at least one barrier coating 104 and at least one aqueous barrier coating 106 over at least a portion of the at least one barrier coating 104. In one or more example, the paperboard substrate 102 contains chemical or mechanical pulp. In one or more examples, the paperboard substrate 102 is bleached or unbleached. Examples of the paperboard substrate 102 include, but are not limited to, an uncoated natural kraft (UNK) board, a solid beached sulfate (SBS) board, an uncoated recycled board (URB), a coated white lined chipboard, or an uncoated folding boxboard (FBB).

The thickness of the paperboard substrate 102 may depend on various factors, such as the density of the paperboard substrate 102. In one or more examples, the paperboard substrate 102 has a caliper thickness in a range of approximately 2 points to approximately 36 points. In one or more examples, the paperboard substrate 102 has a caliper thickness in a range of approximately 6 points to approximately 30 points. In one or more examples, the paperboard substrate 102 has a caliper thickness in a range of approximately 8 points to approximately 24 points. In one or more examples, the paperboard substrate 102 has a caliper thickness in a range of approximately 14 points to approximately 20 points. In one or more examples, the paperboard substrate 102 has a caliper thickness in a range of approximately 16 points to approximately 18 points. As used herein, 1 point equals approximately 0.001 inch (in) or approximately 25.4 micrometers (μm).

The weight of the paperboard substrate 102 may depend on various factors. In one or more examples, the paperboard substrate 102 has a basis weight (e.g., an uncoated basis weight) of at least 25 pounds (lbs) per 3,000 square feet (ft2). In one or more examples, the paperboard substrate 102 has a basis weight ranging from approximately 40 pounds to approximately 400 pounds per 3,000 square feet. In one or more examples, the paperboard substrate 102 has a basis weight ranging from approximately 60 pounds to approximately 350 pounds per 3,000 square feet. In one or more examples, the paperboard substrate 102 has a basis weight ranging from approximately 80 pounds to approximately 300 pounds per 3,000 square feet. In one or more examples, the paperboard substrate 102 has a basis weight in a range of approximately 100 pounds to approximately 250 pounds per 3,000 square feet. In one or more examples, the paperboard substrate 102 has a basis weight in a range of approximately 150 pounds to approximately 180 pounds per 3,000 square feet. In one or more examples, the paperboard substrate 102 has a basis weight in a range of approximately 180 pounds to approximately 220 pounds per 3,000 square feet.

One specific, non-limiting example of the paperboard substrate 102 is 13-point, 150 pounds per 3000 square feet SBS TruServ™ cupstock manufactured by WestRock Company of Atlanta, Ga. Another specific, nonlimiting example of a suitable cellulosic substrate 46 is 18-point, 185 pounds per 3000 square feet SBS TruServ™ cupstock manufactured by WestRock Company.

In one or more examples, the barrier coating 104 is applied using any suitable technique or method. In one or more examples, the barrier coating 104 is applied using one or more coaters (e.g., blade coaters and/or rod coaters). In one or more examples, the barrier coating 104 is applied on a paper machine. In one or more examples, the barrier coating 104 is applied on an off-machine coater line. In one or more examples, the barrier coating 104 (e.g., the interior sidewall barrier coating 104-1 and the interior bottom barrier coating 104-2) forms a portion of the exposed, interior surface of the coated paperboard container 100. In one or more examples, the exterior barrier coating 162 (e.g., the exterior sidewall barrier coating and the exterior bottom barrier coating) forms the exposed, exterior surface of the coated paperboard container 100.

In one or more examples, the aqueous barrier coating 106 is applied using any suitable technique or method. In one or more examples, the aqueous barrier coating 106 is applied using a spray application mechanism (e.g., the sprayer 166 shown in FIG. 7). In one or more examples, the aqueous barrier coating 106 is applied after formation of the tubular structure 120, either as an immediate step following the containers (e.g., cups) being formed on a converting machine followed by a drying process or as additional off-line coating and drying steps after the container (e.g., cups) are formed on a converting machine. In one or more examples, the aqueous barrier coating 106 forms at least a portion of the exposed, interior surface of the coated paperboard container 100.

In one or more examples, the barrier coating 104 and/or the exterior barrier coating 162, when present, is applied to the paperboard substrate 102 at various coat weights. In one or more examples, the barrier coating 104 is applied at a coat weight of approximately 2 pounds to approximately 12 pounds per 3,000 square feet. In one or more examples, the barrier coating 104 is applied at a coat weight of approximately 4 pounds to approximately 11 pounds per 3,000 square feet.

In one or more examples, the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 include a binder.

In one or more examples, the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 include a pigment.

In one or more examples, the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 include the binder and the pigment.

In one or more examples, a ratio of the binder to the pigment is at least approximately 1:2 by weight. In one or more examples, the ratio of the binder to the pigment is approximately 1:2 to approximately 9:1 by weight. In one or more examples, the ratio of the binder to the pigment is approximately 1:1 to approximately 4:1 by weight. In one or more examples, the ratio of the binder to the pigment is approximately 1:1 by weight.

In one or more examples, the binder of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 is or includes an aqueous binder. In one or more examples, the aqueous binder includes styrene-acrylate (SA). In one or more examples, the aqueous binder “consists essentially of” styrene-acrylate. In one or more example, the aqueous binder may “consist of” styrene-acrylate. In one or more examples, the aqueous binder is or includes a mixture of binders that includes styrene-acrylate. Other aqueous binders are also contemplated, such as, but not limited to, acrylic, styrene butadiene, polyvinyl acetate, ethylene acrylic acid, polyvinyl acrylic, polyolefin, polyester, polylactic acid, polyhydroxy alkanoate, epoxy, and polyurethane, and combinations thereof.

In one or more examples, the binder of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 is or includes latex.

In one or more examples the binder of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 has a glass transition temperature (e.g., when dried) of 20° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) of 23° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) of 25° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) of 28° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) of 30° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) of 35° C. or higher. In one or more examples, the binder has a glass transition temperature (e.g., when dried) in a range of 20° C. to 60° C. In one or more examples, the binder has a glass transition temperature (e.g., when dried) in a range of 25° C. to 45° C. In one or more examples, the binder has a glass transition temperature (e.g., when dried) in a range of 28° C. to 32° C.

Specific, non-limiting examples, of suitable binders include: ACRONAL® S 728 (23 Tg, ° C.), BASF Corporation; CARTASEAL® SCR (30 Tg, ° C.), Achroma; RHOPLEX™ C-360 (32 Tg, ° C.), The Dow Chemical Corporation; ACRONAL® S 866 (39 Tg, ° C.), BASF Corporation; RHOBARR™ 320 polyolefin dispersion, The Dow Chemical Corporation; ACRONAL® S504 (4 Tg, ° C.), BASF Corporation; RHOPLEX® C-340 (8 Tg, ° C.), The Dow Chemical Corporation; and ACRONAL® 4377 X (11 Tg, ° C.), BASF Corporation.

In one or more examples, the pigment of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 has a controlled particle size distribution. In one or more examples, the pigment is or includes (e.g., is comprised of) relatively fine powders, such at least 60 percent (by weight) of the pigment is comprised of particles having a particle size of less than 2 microns. In one or more examples, at least 70 percent (by weight) of the pigment is comprised of particles having a particle size of less than 2 microns. In one or more examples, at least 80 percent (by weight) of the pigment is comprised of particles having a particle size of less than 2 microns. In one or more examples, at least 90 percent (by weight) of the pigment is comprised of particles having a particle size of less than 2 microns. In one or more examples, at least 95 percent (by weight) of the pigment is comprised of particles having a particle size of less than 2 microns.

In one or more examples, the pigment of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 includes a clay pigment. In one or more examples, the clay pigment includes kaolin clay, such as a fine kaolin clay. In one or more examples, the clay pigment includes a platy clay, such as a high aspect ratio platy clay (e.g., an average aspect ratio of at least 20:1, an average aspect ratio of at least 25:1, an average aspect ratio of at least 30:1, an average aspect ratio of at least 40:1, an average aspect ratio of at least 50:1, as an average aspect ratio of at least 60:1, etc.).

In one or more examples, the pigment of the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and/or the aqueous barrier coating 106 includes a calcium carbonate (CaCO3) pigment. In one or more examples, the calcium carbonate pigment is a coarse ground calcium carbonate with a particle size distribution in which approximately 60 percent of the particles are less than approximately 2 microns. In one or more examples, the calcium carbonate pigment is a fine ground calcium carbonate with a particle size distribution in which approximately 90 percent of the particles are less than approximately 2 microns. In one or more examples, the calcium carbonate pigment is a fine ground calcium carbonate with a mean particle size of approximately 0.4 microns.

In one or more examples, the pigment is a pigment blend that includes both clay pigment and calcium carbonate pigment. In one or more examples, the pigment blend includes one or more of the clay pigment examples described above. In one or more examples, the calcium carbonate pigment includes one more of the calcium carbonate examples described above.

Specific, non-limiting, examples, suitable pigments include: HYDRAFINE® 90W, No. 1 ultrafine kaolin clay, KaMin LLC of Macon, Ga.; BARRISURF HX, platy clay with high aspect ratio, IMERYS Kaolin, Ga.; XP 6170™, platy clay with high aspect ratio, IMERYS Kaolin, Ga.; HYDROCARB® 60, coarse ground calcium carbonate (particle size 60% <2 micron), Omya AG of Oftringen, Switzerland; ROPAQUE™ AF-1352, styrene acrylic polymeric pigment (1.3 micron particles size, 53% void volume), The Dow Chemical Company; and HYDROCARB® 90, fine ground calcium carbonate (particle size 90% <2 micron), Omya AG of Oftringen, Switzerland.

Other examples of suitable pigments are also contemplated, such as, but not limited to, inorganic pigments, plastic pigments, titanium dioxide pigments, talc pigment, and the like or combinations thereof.

Various techniques can be used to coat the paperboard substrate 102 with the barrier coating 104, the exterior barrier coating 162 (e.g., when present), and the aqueous barrier coating 106. In one or more examples, a barrier coating composition (e.g., the composition of the paperboard substrate 102 with the barrier coating 104, the exterior barrier coating 162, and/or the aqueous barrier coating 106) is prepared by mixing the selected binder with the selected pigment. The barrier coating composition is then applied on at least one side, or major surface, of the paperboard substrate 102, as described herein above.

Optionally, in one or more examples, a base coating is applied to the paperboard substrate 102 before the barrier coating 104 and/or the exterior barrier coating 162 (e.g., the barrier coating composition) is applied. The base coating may be applied by a suitable method, such as using one or more coaters either on the paper machine or on the off-machine coater line. In one or more examples, the base coating includes similar ingredients (e.g., composition) as the barrier coating 104 and/or the exterior barrier coating 162, namely a binder and a pigment. However, in one or more examples, the ratios may be different, namely, a ratio of the binder to the pigment in the base coating may be about 25:100 to about 45:100 by weight.

In one or more examples, non-barrier coatings (e.g., the non-barrier coating 160) may additionally be provided to the paperboard substrate 102, such as to allow for printing of text or graphics. In one or more examples, the non-barrier coating 160 is an aqueous non-barrier coating that includes similar ingredients (e.g., composition) as the barrier coating 104 and/or the exterior barrier coating 162 (e.g., when present), namely a binder and a pigment.

In one or more examples, the barrier coating 104 includes more than one layer of material. In one or more examples, the barrier coating 104 includes an oil barrier layer (e.g., first barrier layer) disposed on the interior surface 116 of the coated paperboard container 100 (e.g., on the interior sidewall-surface 134 and/or the interior bottom-surface 138) and a water barrier layer (e.g., second barrier layer) disposed on, or over, the oil barrier layer such that the oil barrier layer is positioned between the water barrier layer and the paperboard substrate 102.

In one or more examples, the water barrier layer is applied to the paperboard substrate 102 at any one of various coat weights (e.g., on a dry basis). In one or more examples, the water barrier layer is applied at a coat weight of at least approximately 4 pounds per 3,000 ft2, as dried. In one or more examples, the water barrier layer is applied at a coat weight of approximately 4 pounds per 3,000 ft2 to approximately 20 pounds per 3,000 ft2, as dried. In one or more examples, the water barrier layer is applied at a coat weight of approximately 6 pounds per 3,000 ft2 to approximately 16 pounds per 3,000 ft2, as dried. In one or more examples, the water barrier layer is applied at a coat weight of approximately 8 pounds per 3,000 ft2 to approximately 12 pounds per 3,000 ft2, as dried.

In one or more examples, the water barrier layer includes the binder and the pigment. The water barrier layer may include a single layer or may include at least two layers without departing from the scope of the present disclosure. In one or more examples, the ratio of the pigment to the binder may be at most 1 part (by weight) pigment per 1 part (by weight) binder. In one or more examples, the ratio of the pigment to the binder may be about 1:1 to about 1:9 by weight. In one or more examples, the ratio of the pigment to the binder can be about 1:1.5 to about 1:6 by weight. In one or more examples, the ratio of the pigment to the binder can be about 1:2 to about 1:4 by weight.

In one or more examples, the oil barrier layer is hydrophilic or is water soluble. In one or more examples, the oil barrier layer includes one or more polymers. In one or more examples, the oil barrier layer includes polyvinyl alcohol (PVOH), such as Exceval™ HR-3010, a modified PVOH resin, supplied by Kuraray America Incorporated of Houston, Texas. In one or more examples, the oil barrier layer includes carboxymethylcellulose (CMC). In one or more examples, the oil barrier layer includes sodium (Na) carboxymethylcellulose, such as Finnfix® BBP HISS, a purified low viscous sodium carboxymethylcellulose, supplied by CP Kelco U.S. Incorporated of Atlanta, Ga. In one or more examples, the oil barrier layer includes alginate. In one or more examples, the oil barrier layer includes microfibrillated cellulose (MFC). Other water-soluble polymers are also contemplated, such as protein, hydroxypropyl methylcellulose (HPMC), hydroxyethyl cellulose (HEC), polyacrylic acid (PAA), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG) and combinations thereof.

In one or more examples, the oil barrier layer is applied to the paperboard substrate 102 at various coat weights (e.g., on a dry basis). In one or more examples, the oil barrier layer is applied at a coat weight of at least approximately 0.5 pounds per 3,000 ft2, as dried. In one or more examples, the oil barrier layer is applied at a coat weight of approximately 0.5 pounds per 3,000 ft2 to approximately 4.0 pounds per 3,000 ft2, as dried. In one or more examples, the oil barrier layer is applied at a coat weight of approximately 1.0 pounds per 3,000 ft2 to approximately 3.0 pounds per 3,000 ft2, as dried. In one or more examples, the oil barrier layer is applied at a coat weight of approximately 1.5 pounds per 3,000 ft2 to approximately 2.5 pounds per 3,000 ft2, as dried. In one or more examples, the oil barrier layer is applied at a coat weight of approximately 0.5 pounds per 3,000 ft2 to approximately 2.0 pounds per 3,000 ft2, as dried.

In one or more examples, the oil barrier layer includes the pigment. The pigment component of the oil barrier layer may be (or may include) various materials. Other pigments, such as plastic pigments, titanium dioxide pigment, talc pigment and the like, may be used without departing from the scope of the present disclosure.

The coated paperboard container 100 (e.g., the cup 124) described herein shows improved repulpability performance compared to conventional paperboard containers (e.g., cups) having the polyethylene extrusion coating. In one or more examples, the coated paperboard container 100 has a repulpability yield of 75% accepts or greater, preferably 80% accepts or greater, more preferably 85% accepts or greater, more preferably 90% accepts or greater.

The coated paperboard container 100 (e.g., the cup 124) described herein also shows comparable performance and properties as paperboard containers (e.g., cups) having the polyethylene extrusion coating. In one or more examples, the coated paperboard container 100 has a sidewall seam bond strength of 30 pounds per inch (lbs/in) or greater, preferably 40 pounds per inch or greater, more preferably 50 pounds per inch or greater. In one or more examples, the coated paperboard container 100 has a wet rigidity loss of 50% or less, preferably 40% or less, more preferably 30% or less, more preferably 20% or less, even more preferably 10% or less. In one or more examples, the coated paperboard container 100 has a 30 minute water Cobb test of 20 gram per square meter (g/m2) or less, preferably 10 g/m2 or less, more preferably 5 g/m2 or less. In one or more examples, the coated paperboard container 100 has a staining brightness loss of 20% or less, preferably 10% or less, more preferably 5% or less. In one or more examples, the coated paperboard container 100 has a blocking rating of 3.5 or less, preferably 3.0 or less, more preferably 2.0 or less. In one or more examples, the coated paperboard container 100 has fiber tear of 80% or greater, preferably 90% or greater, when the container seams are separated.

The preceding detailed description refers to the accompanying drawings, which illustrate specific examples of the disclosed coated paperboard container and method described herein. It will be understood that the disclosed examples are merely exemplary embodiments of the way in which certain aspects of the of the disclosed coated paperboard container and method can be implemented and do not represent an exhaustive list of all of the ways the of the disclosed coated paperboard container and method may be embodied. Other examples having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same feature, element, or component in the different drawings. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. Throughout the present disclosure, any one of a plurality of items may be referred to individually as the item and a plurality of items may be referred to collectively as the items. Moreover, as used herein, a feature, element, component, or step preceded with the word “a” or “an” should be understood as not excluding a plurality of features, elements, components or steps, unless such exclusion is explicitly recited.

Illustrative, non-exhaustive examples, which may be, but are not necessarily, claimed, of the subject matter according to the present disclosure are provided above. Reference herein to “example” means that one or more feature, structure, element, component, characteristic, and/or operational step described in connection with the example is included in at least one aspect, embodiment, and/or implementation of the subject matter according to the present disclosure. Thus, the phrases “an example,” “another example,” “one or more examples,” and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example. Moreover, the subject matter characterizing any one example may be, but is not necessarily, combined with the subject matter characterizing any other example.

It is to be understood that not necessarily all objects or advantages may be achieved in accordance with any particular example described herein. Thus, for example, those skilled in the art will recognize that certain examples may be configured to operate in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

It should be appreciated that, when used to modify a structure, an element, an item, a component or a feature described herein, the terms “front,” “back,” “rear,” “bottom,” “top,” “left,” “right,” “side,” “end,” “upper,” “lower,” “interior,” “exterior,” as well as similar terms or other forms of such terms, are relative and refer to an example of a spatial relationship between structures, elements, items, components or features. As such, examples of the coated paperboard container 100, described herein and illustrated in the figures, are not intended to be limited by the specific relative terms used to describe any structure, element, item, component or feature thereof.

Conditional language such as, among others, “can” or “may,” unless specifically stated otherwise, are otherwise understood within the context as used in general to convey that certain examples include, while other examples do not include, certain features, elements and/or steps.

Unless otherwise indicated, the terms “first,” “second,” “third,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item.

Unless otherwise stated herein, values for measurable or quantifiable properties, include approximate values. Approximate values, such as use herein of the term “approximately” or “about,” refer to or represent a condition that is close to, but not exactly, the stated condition that still performs the desired function or achieves the desired result. For instance, an approximate value refers to a condition that is within an acceptable predetermined tolerance or accuracy, such as to a condition that is within 10% of the stated condition. However, approximate values or the terms “approximately” and “about” do not exclude a condition that is exactly the stated condition. As used herein, the term “substantially” refers to a condition that is essentially the stated condition that performs the desired function or achieves the desired result.

Those skilled in the art will appreciate that not all elements described and illustrated in FIGS. 1-8 need be included in every example and not all elements described herein are necessarily depicted in each illustrative example. Unless otherwise explicitly stated, the schematic illustrations of the examples depicted in FIGS. 1-8 are not meant to imply structural limitations with respect to the illustrative example. Rather, although one illustrative structure is indicated, it is to be understood that the structure may be modified when appropriate. Additionally, modifications, additions and/or omissions may be made to the illustrated structure.

Further, references throughout the present specification to features, advantages, or similar language used herein do not imply that all of the features and advantages that may be realized with the examples disclosed herein should be, or are in, any single example. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an example is included in at least one example. Thus, discussion of features, advantages, and similar language used throughout the present disclosure may, but do not necessarily, refer to the same example.

The described features, advantages, and characteristics of one example may be combined in any suitable manner in one or more other examples. One skilled in the relevant art will recognize that the examples described herein may be practiced without one or more of the specific features or advantages of a particular example. In other instances, additional features and advantages may be recognized in certain examples that may not be present in all examples. Furthermore, although various examples of the coated paperboard container 100 and method have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.

COATED PAPERBOARD CONTAINERS AND METHODS

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