|Publication number||US20060131257 A1|
|Application number||US 11/017,258|
|Publication date||Jun 22, 2006|
|Filing date||Dec 20, 2004|
|Priority date||Dec 20, 2004|
|Publication number||017258, 11017258, US 2006/0131257 A1, US 2006/131257 A1, US 20060131257 A1, US 20060131257A1, US 2006131257 A1, US 2006131257A1, US-A1-20060131257, US-A1-2006131257, US2006/0131257A1, US2006/131257A1, US20060131257 A1, US20060131257A1, US2006131257 A1, US2006131257A1|
|Inventors||Erik Gatewood, Peter Crandall|
|Original Assignee||Ball Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (14), Classifications (9), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Technical Field
The present invention is directed to molded plastic bottles having a champagne style bottom structure closing the container lower end. The phrase champagne style is used in reference to a base having an outside surface rotationally symmetric about a longitudinal axis of the bottle including a convex heel having an upper margin integrally formed with the lower end portion of the bottle sidewall, and a central concavity separated from the convex heel by a continuous standing ring that supports the bottle on any underlying planar surface.
The present invention particularly relates to blow-molded containers of biaxially oriented thermoplastic materials such as polyethylene terephthalate that are designed to be filled with a hot liquid or semi-liquid product and hermetically sealed, generally referred to as thin-walled, hot-fill containers. The invention pertains to improvements in the design of such containers intended to achieve a container base that, despite the low weight of polymer used to form the container, resists the hydraulic and thermal shock of the entering hot product during a filing operation, yet when cooled, retains the desired container configuration despite the development of a partial vacuum within the container.
2. General Background
It is well recognized that the exposure of any plastic container to elevated temperatures tends to soften the plastic material and make the container less resistant to deformation. Thin-walled, hot-fill containers are typically used for packaging beverages and other food products that must be placed in the container while hot, the container being quickly capped to preserve the quality of the contents. During the filling process, the container is subjected to temperatures from the hot product on the order of about 85° C. The interior of the container base is also subjected to a hydraulic force from the fast flowing hot product as it enters the container. The combination of the thermal and hydraulic forces can easily cause deformation of the container base, which if insufficiently controlled can lead to failure during the immediately subsequent capping operation.
The desire for stability of base configuration is not limited to hot-filled containers. Plastic containers used for beverages and other food products that are subjected to a post-capping pasteurization process are also subjected to considerable internal pressures that can lead to base deformation. During a typical pasteurization process, the contents of the container are heated, to a temperature that is within the general range of about 62° to 67° C. As the temperature rises during the pasteurization process, the internal pressure also rises, sometimes to a level of about 2 to 2½ times higher than what occurs during the packaging of non pasteurized beverages. Under these circumstances, the base of the molded plastic container is vulnerable to outward deformation due to the internal pressures, which can affect the continued serviceability of the container.
Dimensional stability in the base region of molded plastic containers is most important, and particularly in the portions of the base region that are designed to support the container with respect to any underlying surface. In the case of a champagne type base, the dimensional stability of the areas adjacent to the annular support ring is particularly important. Thus, there is a continuing need for an improved molded plastic container having a base that exhibits outstanding dimensional stability under conditions of relatively high pressure and/or temperature and, in particular, that is designed to be particularly resistant to deformation in areas of the base that are designed to support the container with respect to any underlying surface.
A molded polymeric container of the present invention satisfies such needs by providing a champagne type base having an annular contact ring for supporting the container with respect to an underlying surface. An annular step is situated immediately radially inward of the annular contact ring, the annular step having a substantially vertical outer wall and a substantially horizontal inner wall. A push-up area is provided at a central portion of the base that is immediately adjacent to and surrounds the longitudinal axis of the container. A transition region is interposed between the push-up area and the annular step that provides for outstanding base stabilization. The transition region includes an upwardly arching surface extending between the annular step and the push-up area with a plurality of integrally molded, spaced apart, radially extending and downwardly projecting hollow ribs. Each of the ribs has a lower curved surface extending substantially continuously from the push-up area to the inner margin of the annular step.
The upwardly arching surface of the container base of the present invention can have a radius of curvature RS that is greater than the radius of curvature of the rib lower surface RR. The radius of curvature RS can be between about 1.5 RR and 2.0 RR, and in a preferred embodiment the radius of curvature RS can be about 1.7 RR. The ratio of the height to base width of each rib can be less than 1.0 down to at least about 0.7. Each of the ribs can have two sides diverging from the lower curved surface to an adjacent portion of the upwardly arching surface. The angle of divergence of the two sides can be between about 25° and about 35°. The contact ring can be defined by a horizontal planar annulus that can be several times the width of the horizontal inner wall of the annular step. The push-up area of the base can include a horizontal planar ring with a central depending nib aligned with the longitudinal axis of the container.
The champagne type base of the present invention exhibits exceptionally stable geometry from manufacture through typical hot-fill conditions and subsequent storage despite the use of a modest amount of polymer. This base can be combined with a variety of side wall structures to provide a remarkably satisfactory container for hot-fill operations. The scope of the containers that can be constructed with a champagne type base of the present invention will become more apparent from the following description and accompanying drawings detailing an illustrative example of the present invention.
A container 10 of the present invention is shown in
A shoulder portion 26 extends outward and downward from a lower margin of the neck portion 24. The shoulder portion 26 can include an indented hoop ring 28 to provide added strength to the container 10. A bumper ring 30 can be provided at a lower margin of the shoulder portion 26 that can define the maximum radius R of the container sidewall 32 measured from the axis Y. A lower margin of the bumper ring 30 can also define the upper margin 34 of a label receiving portion 36 that is intended to receive a separate label, not shown. The label can be a sheet of plastic, paper, or other similar material of suitable dimension that can surround the entire sidewall 32 of the container 10. The label typically covers the container 10 from the upper margin 34 down to the lower margin 38 of the label receiving portion 36. The label receiving portion 36 can also include one or more reinforcing hoop rings 40. A plurality of vacuum compensation panels 42 can also be provided within the label receiving portion 36 of the sidewall 32. A convex heel portion 44 extends downward from the container sidewall 32 to an annular contact ring 46 that supports the container 10 with respect to any underlying surface.
The convex heel portion 44 and annular contact ring 46 form the outer margin of the base 48 of container 10 shown in FIGS. 2 to 5. When viewed in a vertical section as shown in
A transition region 62 extends radially inward from the inner margin 60 of the annular step 54. The transition region 62 includes a plurality of upwardly arching segments 64 that are spaced from each other by a plurality of ribs 66. When viewed in a vertical section as shown in
Both the upwardly arching segments 64 and ribs 66 converge to an inner margin 72 that defines the outer perimeter of a central push-up area 74 immediately surrounding the longitudinal axis Y of the container 10. The central push-up area 74 is generally horizontally planar, but can contain a spru artifact 76. The central push-up area is maintained in position relative to the annular contact ring 46 by virtue of the stress created in the sides 68 of the ribs 66 in the event of any downward displacement of the central push-up area 74. As a result, the champagne type base 48 exhibits exceptionally stable geometry from manufacture through typical hot-fill conditions.
During the blow-molding of a container to have a base of the present invention, the plastic forming the base 48 more intimately contacts the mold interior and is thus subjected to better heat transfer from the plastic forming the base to the cooled mold. This more intimate contact is established because of the previously described special geometric relationships in the base 48 which reduce or eliminate any extreme angles and tapers that commonly are present in similar contemporary base designs. As a result, the plastic forming the base 48 of the present invention cools more completely during a molding cycle of a given length of time. The more thorough cooling results in less post molding creep of the base structure. The more thorough cooling may be used to increase the bottle production rate. The base 48 can be combined with a variety of side walls 32 to provide a remarkably satisfactory container for hot-fill operations.
The foregoing detailed description of the embodiment shown in the Figures should be regarded as merely illustrative rather than limiting, and the following claims, including all equivalents, are intended to define the spirit and scope of this invention.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7732035||May 26, 2007||Jun 8, 2010||Plastipak Packaging, Inc.||Base for plastic container|
|US8272863 *||Jan 5, 2009||Sep 25, 2012||Sidel Participations||Bottom of a mould for a mould for producing thermoplastic containers, and moulding device comprising at least one mould provided with such a bottom|
|US8308007||Feb 17, 2010||Nov 13, 2012||Amcor Limited||Hot-fill container|
|US8602237||Oct 6, 2009||Dec 10, 2013||Graham Packaging Company, L.P.||Pasteurizable and hot-fillable blow molded plastic container|
|US8662332 *||Oct 6, 2009||Mar 4, 2014||Graham Packaging Company, L.P.||Pasteurizable and hot-fillable plastic container|
|US8991628 *||Dec 15, 2010||Mar 31, 2015||Graham Packaging Company, L.P.||Hot-fill jar base|
|US20100119643 *||Jan 5, 2009||May 13, 2010||Sidel Participations||Bottom of a mould for a mould for producing thermoplastic containers, and moulding device comprising at least one mould provided with such a bottom|
|US20110079575 *||Oct 6, 2009||Apr 7, 2011||Graham Packaging Company, L.P.||Pasteurizable and hot-fillable plastic container|
|US20120118899 *||Dec 15, 2010||May 17, 2012||Graham Packaging Company, L.P.||Hot-fill jar base|
|US20130270214 *||Sep 21, 2011||Oct 17, 2013||Red Bull Gmbh||Bottom structure for a plastic bottle|
|EP2155483A1 *||May 21, 2008||Feb 24, 2010||Plastipak Packaging, Inc.||Base for plastic container|
|WO2008147810A1 *||May 21, 2008||Dec 4, 2008||Plastipak Packaging Inc||Base for plastic container|
|WO2010096555A2 *||Feb 18, 2010||Aug 26, 2010||Amcor Limited||Hot-fill container|
|WO2011044095A1 *||Oct 5, 2010||Apr 14, 2011||Graham Packaging Company, L.P.||Blow-molded plastic container having reinforcing base structures|
|U.S. Classification||215/373, 220/606|
|International Classification||B65D90/02, B65D6/28|
|Cooperative Classification||B65D2501/0036, B65D79/005, B65D1/0276|
|European Classification||B65D79/00B, B65D1/02D2C|
|Dec 20, 2004||AS||Assignment|
Owner name: BALL CORPORATION, COLORADO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GATEWOOD, ERIK EDWARD;CRANDALL, PETER JAY;REEL/FRAME:016111/0719;SIGNING DATES FROM 20040504 TO 20040505