Patent Application
20150108146
The present disclosure is generally related to containers and, more particularly, to beverage containers.
Beverage containers, such as beverage cups, are used to hold various beverages, including cold beverages, such as soda and iced tea, and hot beverages, such as coffee and tea. Disposable beverage containers, such as paperboard-based beverage containers, need to have sufficient structural rigidity to hold the beverage while being sufficiently lightweight for shipping and to reduce cost.
Unfortunately, hot beverages rapidly cool once placed in a typical beverage container, while cold beverages rapidly warm. A significant portion of the cooling/warming is typically effected by heat transfer across the walls of the beverage container. Furthermore, heat transfer across the walls of the beverage containers may significantly increase the surface temperature of the beverage container, which may render the beverage container too hot to comfortably handle, or may significantly decrease the surface temperature of the beverage container, which may render the beverage container too cold to comfortably handle.
Additionally, the portion of the beverage container at the upper end (e.g., near the opening of the beverage container) is often times flimsy and can be accidentally crushed when a consumer grips the cup, thus, damaging the beverage container and causing the beverage to spill.
Efforts have been made to reduce heat transfer across the walls of the beverage container and reduce the likelihood of the beverage container from collapsing. Unfortunately, these efforts have encountered various obstacles. For example, the side walls may be thickened, which increases the cost and weight of the beverage container. Additional stiffeners, such as a corrugated overwrap, may be used; however, stiffeners may provide a thermally conductive pathway from the side wall of the beverage container to the exterior of the overwrap. Polystyrene foam beverage containers may provide improved insulation, but tend to be fragile and are not biodegradable. Environmentally friendly beverage containers, while more structurally robust than polystyrene foam containers, tend to provide only limited insulation.
Accordingly, those skilled in the art continue with research and development efforts in the field of beverage containers.
In one embodiment, the disclosed container may include a base container including a side wall that extends about a longitudinal axis to define an internal volume, an overwrap positioned over the side wall, and an adhesive connecting the overwrap to the side wall, the adhesive consisting essentially of a single ring extending substantially circumferentially around the side wall. The ring of adhesive may space the overwrap from the side wall. Additionally, the ring of adhesive may structurally reinforce the side wall.
In another embodiment, the disclosed container may include a base container having a side wall that extends about a longitudinal axis to define an internal volume, the side wall including an upper end portion and a lower end portion, an overwrap positioned over the side wall, and an adhesive connecting the overwrap to the side wall, the adhesive extending substantially circumferentially around the side wall to form a ring around the base container proximate the upper end portion, wherein the container has a wet/hot rigidity of at least 810 grams-force.
In another embodiment, the disclosed container may include a base container including a side wall that extends about a longitudinal axis to define an internal volume, the side wall including an upper end portion and a lower end portion, an overwrap positioned over the side wall, and an adhesive connecting the overwrap to the side wall, the adhesive extending substantially circumferentially around the side wall to form at least one ring around the base container proximate the upper end portion, wherein the container has a dry rigidity and a wet/hot rigidity, the dry rigidity being at least about 1,100 grams-force, the wet/hot rigidity being at least about 60 percent of the dry rigidity.
In another embodiment, the disclosed container may include a base container including a side wall that extends about a longitudinal axis to define an internal volume, an overwrap positioned over the side wall, and an adhesive connecting the overwrap to the side wall, wherein the container is a 20-ounce container weighing at most about 26 grams, and wherein the container has a wet/hot rigidity of at least about 810 grams-force.
In another embodiment, the disclosed container may include a base container including a side wall that extends about a longitudinal axis to define an internal volume, an overwrap positioned over the side wall, and an adhesive connecting the overwrap to the side wall, wherein the container is a 20-ounce container, wherein the container includes at most about 0.8 grams (dry weight) of the adhesive, and wherein the container has a wet/hot rigidity of at least about 810 grams-force.
In yet another embodiment, disclosed is a method for manufacturing a beverage container, the method may include the steps of: (1) providing a base container including a side wall that extends about a longitudinal axis to define an internal volume, the side wall including an upper end portion and a lower end portion, (2) providing an overwrap, (3) applying an adhesive to at least one of the side wall and the overwrap, the adhesive extending substantially circumferentially around the side wall to form a ring of adhesive around the base container proximate the upper end portion of the side wall, and (4) forming a layered structure including the side wall, the overwrap, and the ring of adhesive positioned between the side wall and the overwrap, wherein the ring of adhesive defines a gap between the overwrap and the side wall.
Other embodiments of the disclosed beverage container will become apparent from the following detailed description, the accompanying drawings and the appended claims.
The following detailed description refers to the accompanying drawings, which illustrate specific embodiments of the disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same element or component in the different drawings.
The disclosed reinforced container may be formed as a multi-wall (e.g., double-walled) beverage cup, such as a 12-ounce, 16-ounce, or 20-ounce disposable beverage cup. The reinforced container may have a generally frustoconical shape, as shown in the drawings, though reinforced containers having various shapes and configurations may be constructed without departing from the scope of the present disclosure.
Referring to
Thus, the reinforced container 10 may be formed as a layered structure that includes the base container 12, the overwrap 14, and the adhesive 16 to form a side wall 40 (
Referring to
The upper end portion 22 of the side wall 18 of the base container 12 may optionally include a circumferential rim 30. The rim 30 may be formed by outwardly rolling the upper end portion 22 of the side wall 18. Those skilled in the art will appreciate that the rim 30 may provide a structure to which a lid (not shown) may be releasably connected to seal the opening 28 (
Referring to
In a first example construction, the base container 12 may be a paperboard container. For example, the base container 12 may be formed by shaping a paperboard blank (not shown) on a cup-forming machine, such as the PMC 1002 cup/container machine available from Paper Machinery Corporation of Milwaukee, Wis. The paperboard blank may have a cross-sectional thickness T1 of at least about 6 points, such as about 8 to about 24 points, wherein 1 point equals 0.001 inch.
In a second example construction, the base container 12 may be a polymeric container. As one example of the second construction, the base container 12 may be formed by shaping a polymeric blank (not shown), such as polycarbonate or polyethylene terephthalate blank, on a cup-forming machine, such as the PMC 1002P container machine available from Paper Machinery Corporation. As another example of the second construction, the base container 12 may be formed by vacuum molding, extrusion molding, injection molding or thermoforming a polymeric material, such as polycarbonate, polyethylene terephthalate or polystyrene.
At this point, those skilled in the art will appreciate that the base container 12 may be formed from various materials using various techniques, and may be configured in various shapes and sizes, without departing from the scope of the present disclosure.
Optionally, the inner surface 32 of the side wall 18 may be coated with a moisture barrier layer 52, thereby rendering the interior surface 50 of the side wall 18 resistant to moisture penetration when the internal volume 26 is filled with a liquid (not shown), such as coffee or soda. The moisture barrier layer 52 may have a cross-sectional thickness ranging from about 0.5 to about 3.5 points, wherein 1 point equals 0.001 inches. For example, the moisture barrier layer 52 may be (or may include) a layer of polyethylene that has been laminated, extrusion coated or otherwise connected (e.g., with adhesives) to the inner surface 32 of the side wall 18. Other moisture barrier materials useful in the moisture barrier layer 52 are commercially available and known to the skilled artisan.
Referring again to
The overwrap 14 may have an overall surface area that is less than the overall surface area of the side wall 18 (e.g., the outer surface 34 of the side wall 18) of the base container 12. Therefore, the overwrap 14 may cover only a portion of the side wall 18 of the base container 12. As one example, the overwrap 14 may cover at least 50 percent of the side wall 18 of the base container 12. As another example, the overwrap 14 may cover at least 60 percent of the side wall 18 of the base container 12. As another example, the overwrap 14 may cover at least 70 percent of the side wall 18 of the base container 12. As another example, the overwrap 14 may cover at least 80 percent of the side wall 18 of the base container 12. As another example, the overwrap 14 may cover at least 90 percent of the side wall 18 of the base container 12. As yet another example, the overwrap 14 may cover at most 95 percent of the side wall 18 of the base container 12.
Referring again to
In an example construction, the overwrap 14 may be formed from paperboard. The paperboard may be bleached or unbleached, and may have a basis weight of at least about 85 pounds per 3000 square feet and a cross-sectional thickness T2 of at least about 6 points, wherein 1 point equals 0.001 inch. For example, the overwrap 14 may be formed from paperboard, such as linerboard or solid bleached sulfate (SBS), having a basis weight ranging from about 180 to about 270 pounds per 3000 square feet and a thickness T2 ranging from about 12 to 36 points.
Optionally, the paperboard used to form the overwrap 14 may include various components and optional additives in addition to cellulosic fibers. For example, the paperboard used to form the overwrap 14 may optionally include one or more of the following: binders, fillers (e.g., ground wood particles), organic pigments, inorganic pigments, hollow plastic pigments, expandable microspheres and bulking agents, such as chemical bulking agents. Overwraps 14 formed from materials other than paperboard, such as polymeric materials, are also contemplated.
The overwrap 14 may be formed by die-cutting a sheet of stock material, such as paperboard, to produce an overwrap blank (not shown). The overwrap blank may include a substantially trapezoidal, keystone shape to allow the overwrap 14 to closely correspond to the frustoconical shape of the base container 12, as shown in
In an example implementation, the overwrap blank may be wrapped onto the base container 12 to form the layered structure of the side wall 40 of the beverage container 10. Alternatively, the overwrap blank may first be assembled into a sleeve and then the sleeve-shaped overwrap 14 may be positioned over the base container 12 (e.g., the base container 12 may be received by the overwrap 14) to form the layered structure of the side wall 40 of the beverage container 10.
Optionally, the overwrap 14 may include a plurality of bosses, which may be formed by embossing and/or debossing the overwrap 14, as disclosed in U.S. Ser. No. 12/910,951 filed on Oct. 25, 2010, the entire contents of which are incorporated herein by reference.
In one specific, non-limiting example, the beverage container 10 may be formed from a paperboard-based base container 12, a paperboard-based overwrap 14, and a substantially biodegradable adhesive 16 (e.g., a latex adhesive). Therefore, the beverage container 10 may be substantially biodegradable.
Referring to
Optionally, one or more additional rings (not shown) of adhesive 16 may be positioned vertically below ring 48.
In an example construction, the adhesive 16 (e.g., the ring 48 of adhesive 16) may extend in a continuous, substantially straight band around the side wall 18 of the base container 12, as shown in
Since the adhesive 16 may be limited to a single ring 48, a relatively small amount of adhesive 16 may be used, which may reduce overall container weight while still providing rigidity. For a typical 20-ounce container, about 0.4 to about 1.5 grams (wet weight) of adhesive 16 may be used to form the ring 48, such as about 0.6 to about 1.2 grams (wet weight), or about 0.8 to about 1.0 grams (wet weight). Depending on the solids content of the adhesive formulation used, after drying to an equilibrium moisture content, about 0.1 to about 0.8 grams (dry weight) of adhesive 16 may remain on the container 10, such as about 0.3 to about 0.6 grams (dry weight), or about 0.4 to about 0.5 grams (dry weight). For larger containers (e.g., 24-ounce or 36-ounce cups), proportionally more adhesive 16 may be used, while for smaller containers (e.g., 12-ounce or 16-ounce cups), proportionally less adhesive 16 may be used.
Referring again to
The adhesive 16 may include a thickness T3 and a width W (e.g., a bead) upon application (e.g., to the base container 12). The thickness T3 of the adhesive 16 may define the radial dimension of the gap 42 (e.g., the spaced-apart distance between the side wall 18 of the base container 12 and the overwrap 14).
As one example, the thickness T3 of the adhesive 16 may be at least 5 points. As another example, the thickness T3 of the adhesive 16 may be at least 10 points. As another example, the thickness T3 of the adhesive 16 may be at least 20 points. As another example, the thickness T3 of the adhesive 16 may range from about 10 to about 40 points. As yet another example, the thickness T3 of the adhesive 16 may range from about 20 to about 30 points.
As one example, the width W of the adhesive 16 may be at least 5 points. As another example, the width W of the adhesive 16 may be at least 10 points. As another example, the width W of the adhesive 16 may be at least 20 points. As another example, the width W of the adhesive 16 may range from about 10 to about 40 points. As another example, the width W of the adhesive 16 may range from about 20 to about 30 points. As yet another example, the width W of the adhesive 16 may be substantially equivalent to the thickness T3 of the adhesive 16.
Thus, the ring 48 of adhesive 16 may function as a spacer that spaces the overwrap 14 from the base container 12 by a distance corresponding to the thickness T3 of the adhesive 16. The spacing between the overwrap 14 and the base container 12 may define the gap 42 between the overwrap 14 and the base container 12. The gap 42 may insulate the beverage container 10. Portions of the gap 42 not filled with the adhesive 16 may be filled with ambient air.
Those skilled in the art will appreciate that depending upon the method of construction, the adhesive 16 may be applied to the outer surface 34 (
Those skilled in the art will appreciate that various adhesives, including water-based adhesive (e.g., latex adhesives) and organic solvent-based adhesive, may be used to connect the overwrap 14 to the base container 12.
In one particular embodiment, the adhesive 16 may be a thermally insulating adhesive. An adhesive may be deemed thermally insulating if it has a thermal resistance per unit of thickness that is greater than the thermal resistance per unit of thickness of the overwrap 14. For example, the ratio of the thermal resistance per unit of thickness of the adhesive 16 to the thermal resistance per unit thickness of the overwrap 14 may be at least about 1.25:1, such as 1.5:1, 2:1 or even 3:1.
A suitable thermally insulating adhesive 16 may be formed as a composite material that includes an organic binder and a filler. The organic binder may comprise 15 to 70 percent by weight of the adhesive 16 and the filler may comprise 2 to 70 percent by weight of the adhesive 16.
The organic binder component of the thermally insulating adhesive 16 may be any material, mixture or dispersion capable of bonding the overwrap 14 to the side wall 18 of the base container 12. The organic binder may also have insulating properties. Examples of suitable organic binders include latexes, such as styrene-butadiene latex and acrylic latex, starch, such as ungelatinized starch, polyvinyl alcohol, polyvinyl acetate, and mixtures and combinations thereof.
The filler component of the thermally insulating adhesive 16 may include an organic filler, an inorganic filler, or a combination of organic and inorganic fillers. Organic fillers include hard organic fillers and soft organic fillers. Examples of suitable hard organic fillers include sawdust and ground wood. Examples of suitable soft organic fillers include cellulose pulp, pearl starch, synthetic fiber (e.g., rayon fiber), gluten feed, corn seed skin and kenaf core (a plant material). Examples of suitable inorganic fillers include calcium carbonate, clay, perlite, ceramic particles, gypsum and plaster. For example, organic filler may comprise 2 to 70 percent by weight of the thermally insulating adhesive 16 and inorganic filler may comprise 0 to 30 percent by weight of the thermally insulating adhesive 16.
All or a portion of the filler may have a relatively high particle size (e.g., 500 microns or more). The use of high particle size filler material may provide the thermally insulating adhesive 16 with structure such that the adhesive 16 functions to further space the overwrap 14 from the side wall 18 of the base container 12. For example, the thermally insulating adhesive 16 may be formed as a composite material that includes an organic binder and a hard organic filler, such as sawdust, that has an average particle size of at least 500 microns, such as about 1000 to about 2000 microns.
In another particular embodiment, the adhesive 16 (e.g., a thermally insulating adhesive) may be a foam. The foam may be formed by mechanically whipping the components of the adhesive 16 prior to application. Optionally, a foam-forming agent may be included in the adhesive formulation to promote foam formation. As one example, 10 to 60 percent of the foam of the adhesive 16 may be open voids, thereby facilitating the absorption of moisture from the exterior surface 54 of the beverage container 10. As another example, 10 to 30 percent of the foam of the adhesive 16 may be open voids.
In another particular embodiment, the adhesive 16 may be formed from a binder-filler formulation having a pseudoplasticity index in the range of 0.3 to 0.5. Such a pseudoplasticity index may provide the adhesive 16 with a sufficient minimum thickness, while preserving the ability to apply the formulation at a low viscosity. For example, the formulation may have a low shear viscosity in the range of 2,000 to 50,000 centipoises and a high shear viscosity in the range of 100 to 5,000 centipoises. Thus, the viscosity of the adhesive 14 may be sufficient to maintain the thickness T3 defining the gap 42 and keep the overwrap 14 spaced away from the side wall 18 of the base container 12 when the overwrap 14 is applied to the base container 12.
In addition to spacing the overwrap 14 away from the side wall 18 of the base container 12, the ring 48 of adhesive 16 may function as a structural support and provide structural rigidity to the base container 12. Those skilled in the art will recognize that the weakest region of a paperboard-based beverage container is the upper end portion proximate the opening.
Thus, by structurally reinforcing the side wall 18 of the base container 12 with the ring 48 of adhesive 16, the structural rigidity of the side wall 40 of the beverage container 10 may be increased while minimizing the required thickness T1 (
For example, the adhesive 16 having a psuedoplasticity index in the range of 0.3 to 0.5 may provide a structural adhesive that forms a thermally insulating adhesive layer (e.g., the ring 48) with a sufficient minimum thickness (e.g., T3), while preserving the ability to apply the adhesive 16 at a low viscosity. The adhesive 16 may have a lower apparent viscosity at higher shear rates (e.g., high shear viscosity in the range of 100 to 5,000 centipoises) and a higher apparent viscosity at lower shear rates (e.g., low shear viscosity in the range of 2,000 to 50,000 centipoises). The adhesive 16 having a pseudoplasticity index between 0.3 and 0.5 may require less work to apply the adhesive 16 to a work surface (e.g., the side wall 18 of the base container 12 and/or the overwrap 14) due to the low viscosity at the high shear rate. For example, the adhesive 16 may thin and flow readily in response to a higher shear rate, such as when the adhesive 16 is pumped or squeezed through a nozzle or brushed or rolled during application, but will retain its shape in response to a lower shear rate, such as compression between the overwrap 14 and the base container 12.
Thus, the ring 48 of adhesive 16 may provide a structure that maintains a minimum thickness (e.g., T3) (
As one option, the adhesive 16 may additionally include a plasticizer. The plasticizer may comprise 0.5 to 10 percent by weight of the adhesive 16. Examples of suitable plasticizers include sorbitol, Emtal emulsified fatty acids, and glycerine.
As another option, the adhesive 16 may additionally include sodium silicate, which may act as a filler, but is believed to aid in binding and curing of the binder by rapidly increasing viscosity of the binder during the drying process. The sodium silicate may comprise 0 to 15 percent by weight of the adhesive 16, such as about 1 to about 5 percent by weight of the adhesive 16.
As yet another option, the adhesive 16 may be formulated to be biodegradable.
As a specific example, the adhesive 16 may include styrene-butadiene or acrylic SRB latex (binder), wood flour (organic filler), Aero Whip® (foam stabilizer available from Ashland Aqualon Functional Ingredients of Wilmington, Del.), corn fibers (organic filler), calcium carbonate (inorganic filler) and starch (binder), wherein the components of the adhesive 16 have been mechanically whipped together to form a foam. Other examples of suitable adhesives are described in greater detail in U.S. Ser. No. 61/287,990 filed on Dec. 18, 2009, the entire contents of which are incorporated herein by reference.
It has been discovered that heat transfer across the gap 42 (e.g., from proximate the base container 12 to proximate the overwrap 14) may be greatest at the adhesive 16, even when a thermally insulating adhesive is used (i.e., air is generally a better insulator). Therefore, when the beverage container 10 is filled with a hot liquid (not shown), such as coffee, the average surface temperature of the overwrap 14 may be lower relative to the average surface temperatures of side wall 18 of the base container 12 due to the gap 42 between the overwrap 14 and the base container 12, as shown in
Thus, a sufficient amount of adhesive 16 may be used to ensure a proper connection between the overwrap 14 and the base container 12. However, the adhesive 16 may be concentrated between the base container 12 and the overwrap 14 at locations that minimize heat transfer across the gap 42. For example, the adhesive 16 may be concentrated proximate the upper end portion 44 of the overwrap 14, rather than between the base container 12 and a central portion 56 (
For example, as shown in
Due to improved resistance to compression forces F (
Unlike some commercially available (prior art) double wall cups, the disclosed beverage container 10 may retain a substantial amount of rigidity even after being filled with a hot beverage. In one expression, the wet/hot rigidity of the disclosed container 10 may be at least 50 percent of the dry rigidity. In another expression, the wet/hot rigidity of the disclosed container 10 may be at least 55 percent of the dry rigidity. In another expression, the wet/hot rigidity of the disclosed container 10 may be at least 60 percent of the dry rigidity. In another expression, the wet/hot rigidity of the disclosed container 10 may be at least 65 percent of the dry rigidity. In yet another expression, the wet/hot rigidity of the disclosed container 10 may be at least 68 percent of the dry rigidity.
Accordingly, the disclosed beverage container 10 may include an overwrap 14 connected over a base container 12 by an adhesive 16, wherein the beverage container 10 is structurally reinforced by at least one ring 48 of adhesive 16 extending circumferentially around the side wall 18 of the base container 12 and the overwrap 14 is spaced away from the base container by the adhesive 16 to define a gap 42. Furthermore, the adhesive 16 may be arranged between the overwrap 14 and the base container 12 such that the surface of the overwrap 14 is cooler than the surface of the base container 12 when the beverage container 10 is filled with a hot liquid.
The 20-ounce cup 100 shown in
The base container 112 was formed from poly-coated (internal side only) paperboard having a caliper thickness of about 13 points (1 point=0.001 inches). The base container 112 included a rolled rim 130.
The overwrap 114 was formed from uncoated paperboard having a caliper thickness of about 16.5 points. The overwrap 114 included three debossings 102 circumferentially extending about the overwrap 114 and protruding into engagement with the base container 112. The overwrap 114 was wrapped around the base container 112 and the free ends of the overwrap 114 were secured together along a seam 104.
The overwrap 114 was secured to the base container 112 with a single ring 148 of adhesive 116 extending circumferentially around the base container 112. The ring 148 of adhesive 116 was positioned proximate the upper end of the cup 100, slightly below the rolled rim 130.
The adhesive 116 was formulated as shown in Table 1.
The Stadex 235 (dextrin from Tate & Lyle of London, United Kingdom) was mixed with cold water for 15 minutes and then cooked to 190° C. Celvol 502 (polyvinyl alcohol resin from Celanese International Corporation of Dallas, Tex.) was slowly added. The mixture was mixed for 15 minutes and then cooled to 100° C. The pH was adjusted to at least 8. The Acronal S 504 (latex from BASF Aktiengesellschaft Corporation of Germany) was then added, followed by additions of propylene glycol and Triton X100 (surfactant from The Dow Chemical Company of Midland, Mich.). After mixing for 10 minutes, Berchem 4842 (dispersant from Bercen Inc. of Dunham Springs, La.) was added. After 10 additional minutes of mixing, Nalcon 7647 (slimicide from Nalco Company of Naperville, Ill.) was added. Then, after 10 additional minutes of mixing, the viscosity was measured using a #7 spindle at 50 rpm. Water was added as necessary to achieve a viscosity in the range of 1,400 to 1,600 cps. Finally, the wood flour was added to bring the final viscosity within the range of 14,000 to 16,000 cps. The adhesive composition had a solids content in the range of 47 to 53 percent.
Approximately 0.8 to 1.0 grams (wet weight) of the adhesive formulation was used to form the ring 148 of adhesive 116. After drying to an equilibrium moisture content, at most about 0.5 grams, specifically about 0.2 to about 0.4 grams, of the adhesive 116 remained on the cup 100.
The 20-ounce cups of Example 1 were tested for wet/hot rigidity. The result was a wet/hot rigidity averaging at about 895 grams-force, which is significantly higher than competitive paper and polymer-based cups currently on the market. It is believed that a similar wet/hot rigidity value would be obtained for cups constructed in a similar manner, but at other sizes, such as 12-ounce and 16-ounce sizes.
The “wet/hot rigidity” test is a modification of the Solo deflection test known in the industry and disclosed in U.S. Pat. No. 8,152,018 to Smith et al., the entire contents of which are incorporated herein by reference. The wet/hot rigidity test is performed under TAPPI standard conditions. The seam 104 is positioned 90 degrees from the direction of the applied force. The deflection speed should be such that it takes about 3 to 4 seconds to achieve 0.25 inches of deflection. However, unlike the traditional Solo deflection test, the wet/hot rigidity test is performed while the container under test is filled with water at a temperature of 205° F., and after the hot water has been in the container under test for 3 minutes.
Thus, the wet/hot rigidity test measures the peak force required to deflect a container filled with hot liquid by 0.25 inches at a point that is one-third of the way down from the upper edge of the container.
The 20-ounce cups of Example 1 were also tested for dry rigidity. The result was a dry rigidity averaging at about 1,300 grams-force. It is believed that a similar dry rigidity value would be obtained for cups constructed in a similar manner, but at other sizes, such as 12-ounce and 16-ounce sizes.
The “dry rigidity” test is performed under TAPPI standard conditions using the same procedure used for the wet/hot rigidity test, but with a dry cup (i.e., without filling the cup with water at a temperature of 205° F. or otherwise heating the cup outside of TAPPI standard conditions).
Thus, like the wet/hot rigidity test, the dry rigidity test measures the peak force required to deflect a container by 0.25 inches at a point that is one-third of the way down from the upper edge of the container.
Comparing the wet/hot rigidity of a cup to the dry rigidity provides an indication of rigidity retained by the cup after the cup is placed into use. The “rigidity retention” may be expressed as a percentage by dividing the wet/hot rigidity by the dry rigidity, and then multiplying by 100.
For the 20-ounce cups of Example 1, the rigidity retention was about 68.8 percent, which was calculated by dividing the wet/hot rigidity (895 grams-force from Example 2) by the dry rigidity (1,300 grams-force from Example 3).
For comparison, the following commercially available 20-ounce cups were tested for dry rigidity performance and wet/hot rigidity performance: (1) the HOLD&GO® insulated paper hot cup (about 27.9 grams total cup weight) from International Paper, Inc. of Memphis, Tenn.; (2) the Seda Double Wall insulated cup (about 28.1 grams total cup weight) from Seda International Packaging Group SpA of Naples, Italy; (3) the SOLO® DUO SHIELD® insulated paper hot cup (about 24.6 grams total cup weight) from Solo Cup Operating Corporation of Lake Forest, Ill.; (4) the CHINET® RC cup COMFORTCUP® (about 27.8 grams total cup weight) from Huhtamaki Inc. of De Soto, Kans.; (5) the DUNKIN' DONUTS® foam cup from Dunkin' Donuts of America, Inc. of Quincy, Mass.; (6) a basic paper cup; and (7) the THERMO GRIP™ cup (about 26.5 grams total cup weight) from LBP Manufacturing, Inc. of Cicero, Ill. The test results, as well as the rigidity retention, are provided in Table 2.
Although various embodiments of the disclosed beverage container 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.
