Rectangular Container Having Inset Label Panels And Concave Heel Geometry

Abstract

A rectangular plastic container formed by blow molding includes an upper portion, an upper label bumper, a base portion having a heel that curves inward to meet a standing edge at a bottom of the container, and a lower label bumper. The container further includes a body portion disposed between the upper portion and the base portion. The body portion includes front, back, and side label panel areas meeting at rounded corner regions of the body portion. The label panels each having a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion. The front and the back label panel areas are inset from the upper bumper by a distance which is greater than an inset distance of the side label panel areas with respect to the upper bumper.

Description

BACKGROUND

[0001] 1. Technical Field

[0002] This invention generally relates to containers for holding beverages or other liquids or food products. More specifically, this invention relates to rectangular containers having inset label panels and concave heel geometry.

[0003] 2. Related Art

[0004] Plastic containers, such as those made of polyethylene terephthalate (PET), are widely used for packaging liquid and food products. Such containers may be formed using a blow molding process, in which a preform is filled with gas until it fills the interior of a mold having the desired shape of the container. During a stretch blow molding process, for example, the preform is first stretched mechanically with a stretch rod, and as the rod is extended, low-pressure air is introduced to blow an air bubble in the preform. Once the stretch rod is fully extended, high-pressure air is used to blow the expanded preform into the shape of the mold.

[0005] Perishable foods, such as juices and soup, are often filled at an elevated temperature, in a process generally referred to as "hot-fill." In a typical hot-fill process, a liquid or flowable product is charged into a container at elevated temperature, such as 180 to 190.degree. F., under approximately atmospheric pressure, and the container is hermetically sealed using a closure, such as a cap. Upon subsequent cooling of the contents, a vacuum forms within the container due to shrinkage of the contents. By contrast, in a "cold-fill" process, the product is charged into a container approximately at a room temperature under atmospheric pressure, so a vacuum condition does not occur in the container.

[0006] Hot-fill containers typically are designed with vacuum panels formed in the container sidewall that flex in response to a decrease in internal pressure. For example, some plastic containers have several, equidistantly spaced vacuum panels that are configured to enable a circular label to be wrapped around the container. Land areas between the panels provide surfaces around which the label may be applied. Inward flexing of the vacuum panels in response to vacuum pressure prevent severe distortion of the land areas. Other plastic containers are configured to have opposing hand-grips that flex to absorb the internal vacuum. Flexing of the hand-grips in response to internal negative pressure prevents severe distortion of the surfaces to the front and to the rear of the hand-grips, which can receive labels.

[0007] While container designs relying on vacuum panels have been effective, certain limitations and disadvantages are associated with their use, including limitations as to the possible variations in the exterior styling of the container, the need to provide enough plastic material to form the vacuum panels with the requisite thickness, and incompatibility with certain types of package labeling processes. For example, it is difficult to use certain types of pressure sensitive labeling on hot-fill containers that have prominent vacuum panels.

[0008] In addition, while hot-fill containers are designed to withstand internal vacuum conditions, the containers are sometimes subjected to positive internal pressure during the filling process. For example, some filling equipment subjects the container to internal positive pressure for a brief period. Containers having long stiffening ribs or other long stiff structures may, in response to positive internal pressure, locally bulge outwardly in a kink. Such a kink might remain even after the container encounters internal vacuum, or the kink may disappear but leave a wrinkle in the wall of the container. Kinks and wrinkles make a container unappealing and are considered to be commercially undesirable.

[0009] Many existing containers have a large grip portion at the top of the container with large indented grip areas or handles. Such configurations require the label panel to be located below the grip area toward the bottom of the container elevation. This is commercially undesirable, because the product label tends to have better visibility when it is located in the middle or upper portion of the container elevation.

[0010] In rectangular blow-molded containers (including square containers), the corners of the heel portion tend to be more susceptible to damage, because they project from the bottom surface of the container and are likely to receive an impact force if the container is dropped. Moreover, the corners are formed of material that is stretched more than any other portion of the container during the blow molding process, i.e., because the bottom corners of the container are the greatest distance from the initial position of the material of the preform. Thus, the corners may have the thinnest wall thickness of any portion of the container, which makes deformation of or damage to these portions more likely.

SUMMARY

[0011] In one aspect, the present invention provides a rectangular plastic container formed by blow molding. The container includes an upper portion having a finish at the top for receiving a closure, an upper label bumper extending around a periphery of the container at a bottom of the upper portion, a base portion having a heel that curves inward to meet a standing edge at a bottom of the container, and a lower label bumper extending around the periphery of the container at a top of the base portion. The container further includes a body portion disposed between the upper portion and the base portion. The body portion includes front, back, and side label panel areas that meet at rounded corner regions of the body portion. The label panels each have a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion. The front and the back label panel areas are inset from the upper bumper by a distance which is greater than an inset distance of the side label panel areas with respect to the upper bumper.

[0012] In another aspect, the present invention provides a rectangular plastic container formed by blow molding that includes an upper portion having a finish at the top for receiving a closure, an upper label bumper extending around a periphery of the container at a bottom of the upper portion, a base portion having a heel that curves inward to meet a standing edge at a bottom of the container, and a lower label bumper extending around the periphery of the container at a top of the base portion. The container further includes a body portion disposed between the upper portion and the base portion. The body portion including front, back, and side label panel areas. The heel includes indented portions at corners thereof. The indented portions have a depth that gradually decreases with increasing elevation, so that the indented portions merge with the surface of the base at a top portion of the base.

[0013] In another aspect, the present invention provides a rectangular plastic container formed by blow molding that includes an upper portion having a finish at the top for receiving a closure, an upper label bumper extending around a periphery of the container at a bottom of the upper portion, a base portion having a heel that curves inward to meet a standing edge at a bottom of the container, and a lower label bumper extending around the periphery of the container at a top of the base portion. The container further includes a body portion disposed between the upper portion and the base portion. The body portion has front, back, and side label panel areas that meet at rounded corner regions of the body portion. The label panels each have a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion. For each rib, the gap between the portions of the rib is between 0% and about 7% of the circumference of the container at the elevation of the rib.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a front perspective view of a rectangular container in accordance with the present invention.

[0015] FIG. 2 is a front elevation view of the rectangular container.

[0016] FIG. 3 is a side elevation view of the rectangular container.

[0017] FIGS. 4A-B are cross-section views of different parts of the body portion of the rectangular container, as indicated in FIG. 2.

[0018] FIG. 5 is a bottom view of the rectangular container.

[0019] FIG. 6 is a bottom perspective view of the rectangular container.

[0020] FIG. 7 is another front elevation view of the rectangular container.

[0021] FIGS. 8A-D are cross-section views at different elevations of the heel, as indicated in FIG. 7, showing the change in shape of the indented portions of the heel.

[0022] FIG. 9 is a cross-section view of the rectangular container at line 8C-8C in FIG. 7, showing dimensional references for defining the shape of the indented portions of the heel.

DETAILED DESCRIPTION

[0023] FIGS. 1-3 show a plastic rectangular container 10, which may be, for example, formed of polyethylene terephthalate (PET) in a blow molding process. The container also may be formed of other materials, such as, for example, polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), or a blend comprising the same. The container 10 is suitable for hot-fill processes, in which the container is filled with product at an elevated temperature, capped, and allowed to cool. The container 10 is also suitable for cold-fill processes, in which the container is filled with product at or near room temperature.

[0024] The container 10 has a body portion 6 that forms the central portion of the container and a rounded upper portion 4 that forms the top of the container. A finish 2 extends from the top of the upper portion 4 and includes a threaded portion for receiving a threaded closure (not shown). The body portion 6 has sidewalls 14 that provide front, back, and side label panel areas for the attachment of a label, e.g., a pressure-sensitive label.

[0025] Below the body portion 6 is a base portion 8 that forms the bottom of the container. The base portion 8 has a tapered portion, referred to as the heel 22. At the bottom of the container 10, there is a substantially planar standing edge 26, which allows the container to stand on a flat surface. The base portion 8 also has a reentrant portion 32 that extends up into the middle of the bottom of the container (see FIGS. 5 and 6), such that the standing edge 26 extends around the periphery of the reentrant portion 32.

[0026] Each of the label panel areas of the body portion 6 has a number of horizontal ribs 19 to provide increased strength to the sidewalls 14. Unlike conventional container designs, the horizontal ribs 19 are not continuous around the periphery of the container. Rather, the ribs 19 extend into the corner portions of the sidewalls 14, but do not extend all the way around the corner portions, such that there are gaps in the ribs 19 in the corner portions of the sidewalls. Thus, each rib 19 has separate portions (four portions in this case) that end in the corner portions of the sidewalls 14.

[0027] These discontinuous horizontal ribs 19 act to strengthen each of the label panel areas of the sidewalls 14 to prevent flexure within the label panel areas, while allowing flexure at the corners. Thus, the corners, in effect, operate as hinges. This configuration allows internal and external forces to be at least partially dissipated through flexure of the corner portions, thus preventing undesirable flexure of the label panel areas. It should be noted that the separate portions of each rib 19 may actually meet at the corner (i.e., have a gap of zero), but the rib portions have no depth at this meeting point and therefore still allow hinge-like bending to occur at the corner.

[0028] As shown in FIGS. 2 and 3, an upper label bumper 16 extends around the periphery of the container at the bottom of the upper portion 4, and a lower label bumper 23 extends around the periphery of the container at the top of the base portion 8. The bumpers (16 and 23) are the most outwardly extending structures in the direction transverse to the longitudinal axis of the container. Thus, adjacent containers in a shipping configuration or on a filling line will contact at the bumpers (16 and 23) rather than at the sidewalls 14, thereby preventing damage to the labeling. An upper peripheral groove 17 is positioned between the upper label bumper 16 and the sidewalls 14. Similarly, a lower peripheral groove 21 is positioned between the lower label bumper 23 and the sidewalls 14.

[0029] The upper and lower label bumpers (16 and 23) and upper and lower peripheral grooves (17 and 21) are arranged such that the front and back label panel areas are inset from the label bumpers by a greater amount than the side label panel areas. The greater inset of the front and back label panel areas allows a consumer to lift the container by gripping the front and back label panel areas between their thumb and fingers, because the label bumper acts as a stop to prevent the container from slipping out of the consumer's hand. At the same time, the lesser inset of the side panels allows the front and back labels to present the largest possible surface area to consumers, thereby increasing the commercial desirability of the container.

[0030] In addition, because the label panel areas of the sidewalls can be used as a grip, there is no need to provide a grip portion at the top of the container. As noted above, in conventional containers, such grip areas or handles may take up substantial portions of the top of the container, which may necessitate moving the label area toward the bottom of the container, which is commercially undesirable. By contrast, the container described herein has a label area that is more centrally positioned in elevation, which may be described in terms of the elevation of the bottom of the sidewalls 14 (which provide the label panel areas) relative to the overall height of the container. In one embodiment, the ratio of the elevation of the bottom of the label panels (sidewalls 14) to the height of the container (as measured from the standing edge 26 to the top edge of the finish 2) is between about 0.1 and about 0.4 and is preferably about 0.2.

[0031] The minimum inset of the front and back label panels may be determined based on such factors as the minimum inset necessary to allow the consumer to stably grip the container, which may in turn depend on the overall dimensions and weight of the container when filled. For example, a large capacity container will be heavier when filled and therefore may require a greater inset of the front and back label panels. The maximum front and back label panel inset may depend on such factors as the performance of the container under top load conditions, i.e., when a force is applied to the top of the container. If the inset of the front and back label panels is too great, then the container may deform in the area near the inset at an unacceptably low top load force.

[0032] As noted above, it is generally desirable to have a minimal inset on the side label panels, so as to maintain the greatest possible surface area on the front and back label panels. The minimum inset of the side label panels may be determined based on the minimum distance necessary to prevent the label on the side label panel areas from contacting adjacent containers in a shipping configuration or on a filling line. Although, a side inset distance of zero may be used.

[0033] Based on the criteria discussed above, in one embodiment, the front and back label panel areas may be inset, for example, by a distance of about 0.180 inches from the upper label bumper 16 (measured in the transverse direction), while the side label panel areas may be inset by a distance of about 0.050 inches. In other embodiments, the front and back inset distance may be in a range of about 0.08 inches to about 0.250 inches, which corresponds to between about 2% and about 7% of the depth of the container in the front-to-back transverse distance, as measured between the front and back edge of the upper label bumper 16. As noted above, the side label panels are inset by a smaller distance than the front and back label panel areas (and may have a zero inset). The ratio of the side inset distance to the front and back inset distance may be between zero and about 0.5. In some embodiments the front label panel and the back label panel may be inset by different distances, in which case these distances may be specified separately. Typically, the two side label panels will each be inset by the same distance, but this is not a necessity

[0034] FIGS. 4A and 4B, respectively, show a cross-section of the body portion 6 of the container between ribs 19 and through a rib 19. As discussed above, each rib 19 has separate portions that end in the corner portions of the sidewalls 14, separated by a gap (y.sub.RG). In one embodiment, the gaps, y.sub.RG, that separates the portions of each rib is between 0% and about 7% of the circumference of the container measured at the rib. In the case of a zero-width gap, the rib portions would meet at the corner, but would have zero depth at that point and thus would still allow hinge-like bending to occur at the corner. As can be seen in FIGS. 4A and 4B, the sidewalls 14 of the container may be outwardly convex to help fight the tendency of the sidewalls 14 to pull in and become concave in response to negative pressure in the container, such as typically arises in the hot-filling process. This in turn can help prevent the problems that arise in the labeling process in attempting to apply pressure-sensitive labels to concave surfaces.

[0035] FIGS. 5 and 6 show bottom views of the rectangular container 10. As noted above, the base portion 8 has a tapered heel portion 22 and a reentrant portion 32 that extends inwardly and upwardly into the container. The substantially planar standing edge 26 upon which the container 10 rests surrounds the reentrant portion 32. As shown in FIG. 6, in one embodiment, the heel may have indented portions at the corners, which are most pronounced at the bottom of the container and gradually become shallower with increasing elevation until the indented portions merge with the surface of the container at or near the top of the base portion 8. Thus, the lower bumper 23, which is located at the top of the base portion 8, has the desired rectangular shape without indentations.

[0036] As noted above, the container 10 may be formed by a blow molding process. In such processes, a perform made of, for example, PET and having a particular shape and thickness is stretched and blown using pressurized gas, and also possibly mechanical means, within a mold. The perform assumes the shape of the container, which is the interior shape of the mold. In the case of rectangular containers, the bottom corners of the container are relatively weaker, because the corners are stretched the furthest and therefore are thinner than other parts of the container. The indented portions of the heel 22 help to reduce the distance that the corners must be blown from the perform and therefore result in thicker and stronger corners. Also, the indented portions also help reduce the possibility of damage to the container during handling, because they help reduce the amount of protrusion of the corners.

[0037] The progressively decreasing depth of the indented portions, in the direction away from the standing edge 26, is shown in the cross-sectional views of FIGS. 8A-8D, which are taken at different elevations. The shape of the indented portions of the heel can also be seen in FIG. 6. The progressively decreasing depth of the indented portions may be quantified as shown in FIG. 9, which is a cross-sectional view of the heel 8. In one embodiment, the ratio of the corner relief depth (d.sub.CRD) to the corner relief width (d.sub.CRW) is between 0 and about 0.5, as shown in the following equation:

0.0 .ltoreq. d CRD d CRW .ltoreq. about 0.5 ##EQU00001##

The particular values of this ratio may be varied along the base elevation in order to achieve a desired indentation contour, which will be based on such factors as the height of the base and the maximum desired corner relief depth desired at the standing edge (which in turn depends on factors such as the standing stability of the bottle). Also, the ratio is higher at the bottom of the bottle, because this is the most difficult part of the container to blow in the blow molding process due to the height of the reentrant portion 32 of the base portion 8 (see FIG. 6).

[0038] Alternatively, as further shown in FIG. 9, the shape of the indented portion may be quantified in terms of corner relief radius (d.sub.CRR) and the maximum corner distance (d.sub.MCD) is between about 60% and about 95%., as shown by the following equation:

about 0.55 .ltoreq. d CRR d MCD .ltoreq. about 0.9 ##EQU00002##

As shown in FIG. 9, the corner relief radius (d.sub.CRR) is measured from the center of the container to the closest tangent point on the indented corner, and the maximum corner distance (d.sub.MCD) is measured from the center of the container to the squared-off corner of the container, i.e., the point at which perpendicular lines tangent to the front (or back) and side of the container meet. The maximum corner distance (d.sub.MCD) may be obtained from the following equation:

d MCD = ( ( d depth 2 ) 2 + ( d width 2 ) 2 ) ##EQU00003##

where d.sub.depth represents depth of the container and d.sub.width represents width of the container.

[0039] The present invention is illustrated with respect to a preferred embodiment, but the present invention is not limited to the particular structure described in the preferred embodiment of rectangular container 10. It is understood that persons familiar with container technology will recognize additional advantages and features that flow from the present disclosure, and the present invention encompasses such additional advantages and features such that the scope of the invention is limited only by the claims.

Claims

1. A rectangular plastic container formed by blow molding, the container comprising: an upper portion having a finish at the top for receiving a closure; an upper label bumper extending around a periphery of the container at a bottom of the upper portion; a base portion having a heel that curves inward to meet a standing edge at a bottom of the container; a lower label bumper extending around the periphery of the container at a top of the base portion; and a body portion disposed between the upper portion and the base portion, the body portion including front, back, and side label panel areas meeting at rounded corner regions of the body portion, the label panels each having a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion, wherein the front and the back label panel areas are inset from the upper bumper by a distance, d.sub.FI, which is greater than an inset distance, d.sub.SI, of the side label panel areas with respect to the upper bumper.

2. The rectangular plastic container of claim 1, wherein a ratio of the inset distance d.sub.SI of the side label panel areas to the inset distance d.sub.FI of the front and back label panel area is between 0 and about 0.5.

3. The rectangular plastic container of claim 1, wherein a ratio of the inset distance d.sub.SI of the side label panel areas to the inset distance d.sub.FI of the front and back label panel area is between about 0.2 and about 0.4.

4. The rectangular plastic container of claim 1, wherein the front and back label panels are outwardly convex.

5. The rectangular plastic container of claim 4, wherein the side label panels are outwardly convex.

6. The rectangular plastic container of claim 1, wherein the heel comprises indented portions at corners thereof, the indented portions having a depth that gradually decreases with increasing elevation, so that the indented portions merge with the surface of the base at a top portion of the base.

7. The rectangular plastic container of claim 6, wherein a ratio of a depth of each of the indented portions to a width of each of the indented portion is between 0 and about 0.5.

8. The rectangular plastic container of claim 6, wherein, for each of the indented portions, in each plane of elevation, a ratio of a corner relief radius (d.sub.CRR) to a maximum corner distance (d.sub.MCD) is between about 0.55 and about 0.9, where the maximum corner distance (d.sub.MCD) is given by: d MCD = ( ( d depth 2 ) 2 + ( d width 2 ) 2 ) ##EQU00004## where d.sub.depth is a maximum depth of the container in the plane of elevation and d.sub.width is a maximum width of the container in the plane of elevation.

9. The rectangular plastic container of claim 1, wherein, for each rib, the gap y.sub.RG between the portions of the rib is between 0% and about 7% of the circumference of the container at the elevation of the rib.

10. The rectangular plastic container of claim 1, wherein a ratio of an elevation of the bottom of the label panels to the height of the container measured from the standing edge to the top edge of the finish is between about 0.1 and about 0.4

11. The rectangular plastic container of claim 1, wherein a ratio of an elevation of the bottom of the label panels to the height of the container measured from the standing edge to the top edge of the finish is about 0.2.

12. A rectangular plastic container formed by blow molding, the container comprising: an upper portion having a finish at the top for receiving a closure; an upper label bumper extending around a periphery of the container at a bottom of the upper portion; a base portion having a heel that curves inward to meet a standing edge at a bottom of the container; a lower label bumper extending around the periphery of the container at a top of the base portion; and a body portion disposed between the upper portion and the base portion, the body portion including front, back, and side label panel areas, wherein the heel comprises indented portions at corners thereof, the indented portions having a depth that gradually decreases with increasing elevation, so that the indented portions merge with the surface of the base at a top portion of the base.

13. The rectangular plastic container of claim 12, wherein a ratio of a depth of each of the indented portions to a width of each of the indented portion is between 0 and about 0.5.

14. The rectangular plastic container of claim 12, wherein, for each of the indented portions, in each plane of elevation, a ratio of a corner relief radius (d.sub.CRR) to a maximum corner distance (d.sub.MCD) is between about 0.55 and about 0.9, where the maximum corner distance (d.sub.MCD) is given by: d MCD = ( ( d depth 2 ) 2 + ( d width 2 ) 2 ) ##EQU00005## where d.sub.depth is a maximum depth of the container in the plane of elevation and d.sub.width is a maximum width of the container in the plane of elevation.

15. A rectangular plastic container formed by blow molding, the container comprising: an upper portion having a finish at the top for receiving a closure; an upper label bumper extending around a periphery of the container at a bottom of the upper portion; a base portion having a heel that curves inward to meet a standing edge at a bottom of the container; a lower label bumper extending around the periphery of the container at a top of the base portion; and a body portion disposed between the upper portion and the base portion, the body portion including front, back, and side label panel areas meeting at rounded corner regions of the body portion, the label panels each having a plurality of horizontal ribs, each horizontal rib having four portions separated by gaps, such that each of the four portions extends into the corner regions of the body portion, wherein, for each rib, the gap y.sub.RG between the portions of the rib is between 0% and about 7% of the circumference of the container at the elevation of the rib.