MXPA05012650A - A plastic, wide-mouth, blow-molded container with multi-functional base - Google Patents

Abstract

A container can have a body with an integrally formed base attached to the body. The base includes a concave annular wall extending from the container sidewall to a standing surface, and an inner wall extending from the standing surface to a substantially flat inner annular wall. The inner annular wall is recessed in the base and is substantially perpendicular to the container sidewall. The inner annular wall includes a centrally located dimple. The dimple includes a plurality of spaced apart and radially extending indented ribs. One or more of the ribs extend radially into a brace that tapers to meet the inner annular wall.

Description

ULTI-FUNCTIONAL BASE FOR A BLOW-MOLDED CONTAINER, WITH WIDE, PLASTIC ORIFICE FIELD OF THE INVENTION The present invention relates to a base for a wide mouth, blow molded container, and more particularly, the present invention relates to a multi-functional base structure that enables the use of the container in filling processes hot, as well as pasteurization / retort. BACKGROUND OF THE INVENTION Plastic containers, blow molded, particularly those molded from PET, have been used in hot filling applications where the container is filled with a liquid product heated to a temperature in excess of 82 ° C, covered immediately after filling and let cool to ambient temperatures. The plastic containers, molded by sopfado, have also been used in pasteurization and retort processes, where a filled and sealed container is subjected to thermal processing and then cooled to ambient temperatures. Pasteurization and retort methods are frequently used to sterilize solid or semi-solid food products, for example, pickles and sauerkraut, which can be packaged in the container together with a liquid at a temperature lower than 82 ° C and then heated, or placed the product in the container that is then filled with the liquid, which has been previously heated, and the entire contents subsequently heated to a higher temperature. Pasteurization and retort differ from hot fill processing by including heating the contents of a filled container to a specific temperature, typically greater than 93 ° C, until the contents reach a specific temperature, for example 80 ° C, for a predetermined period of time. The retort processes also involve the application of overpressure to the container. In each of these cases, the plastic containers are typically provided with vacuum absorption panels to accommodate volumetric changes in the container as the contents of the sealed container are heated and / or as the contents are cooled inside the container sealed. U.S. Patent No. 6,439,413 issued to Prevot et al. And assigned to Graham Packaging Company, L.P. describes a plastic, wide-mouthed, blow-molded plastic container that can be hot filled and subjected to a retort process, having a side wall with a pair of flexible panels. U.S. Patent Application Serial No. 10 / 129,885 co-pending, filed May 10, 2002 is in the EU national phase of International Application No. PCT / US00 / 31834, assigned to Graham Packaging Company, LP , and describes a wide-mouth container, which can be pasteurized having a novel base. Other wide-mouth plastic containers having side walls with panels are described in the U.S. patents. numbers 5,887,739 granted to Prevot et al; 5,261, 544 issued to Weaver, Jr.; and 5, 092,474 granted to Leigner. A pasteurizable plastic container having side walls with panels and a narrow neck finish is described in U.S. Patent No. 5,908, 128 to Krishnakumar et al. Containers having sidewalls without panels and terminal wall structures that can yield are described in U.S. Pat. Nos. 4,642, 968, 4,667,454 and 4,880, 129 granted to McHenry et al; 5,217,737 issued to Gygax et al; 5,234, 126 granted to Joñas and collaborators; 4,381,061 granted to Cerny et al; 4, 1 25,632 granted to Vosti et al; and 3,409, 1 67 granted to Blanchard. The aforementioned US patents describe containers having several base structures. The structure of a so-called foot base is described, in general, in the U.S. patents. Nos. 4, 355,728 granted to Yoshino et al., 5,71 granted to Petre and collaborators, 3,727, 783 granted to Carmichael, 4,31 8,489 granted to Snyder and collaborators, 5, 1 33,468 granted to Brunson and collaborators, 5,024,340 granted to Alberghini and collaborators, 3, 935,955 granted to Das, 4,892,205, 4, 867,323 and Re. 35, 1 40 granted to Powers and collaborators, and 5, 785, 1 97 granted to Slat. U.S. Patent No. 4,321,483 issued to Dechenne et al. Describes a base having a slightly angled annular surface and a central conical projection.; and the patent of E. OR . No. 4,386,701 issued to Galer discloses a blow molded plastic drum having a base that is designed to efficiently stack with the lid of a similar drum. Plastic containers, including those described in the aforementioned references, have replaced or provided an alternative for glass containers for many applications. However, some food products that must be processed using pasteurization or retort are available in plastic containers. The rigors of such processing present significant challenges for the use of plastic containers, including containers designed for use in hot fill processing. There remains a need to provide plastic containers that can withstand the rigors of pasteurization and retort processing in order to take advantage of the cost savings that can be incurred through manufacturing and recycling. The lighter weight of plastic containers compared to glass can also advantageously reduce shipping costs. International Published Application No. WO 02/0241 8 discloses a container with a base that may be able to withstand the rigors of the pasteurization process. The base includes a large thrust section formed with a sharp transition to the side wall of the container. The base should be fixed by heat to a relatively high crystallinity.

Although the containers and the above-mentioned base structures can function satisfactorily for their intended purposes, there is a need for a wide-mouth, blow molded plastic container that is particularly suitable for packing a variety of viscous and other food products and that have a novel base structure that allows the container to be used in hot filling, pasteurization and retort processes. The base structure must be able to accommodate the increased internal pressure experienced during pasteurization; able to accommodate the vacuum formed in the sealed container during cooling; and capable of resisting inversion, ovation or similar undesirable deformation. A container capable of efficiently stacking with similar containers is also desirable. BRIEF DESCRIPTION OF THE INVENTION With the foregoing in mind, an object of the present invention is to provide a commercially satisfactory, wide-molding, blow-molded container that can be used in hot fill applications, as well as for pasteurization or retort applications. used to pack fluid, viscous and solid food products. Another object of the present invention is to provide a base structure capable of accommodating an internal pressure of the container when the sealed container is subjected to thermal treatment, and capable of accommodating a vacuum during cooling.

Yet another object of the present invention is to provide a container that can be hot filled and pasteurized that has a base that accommodates changes in internal pressure and volume and that resists inversion and other unwanted deformation. A further object of the present invention is to provide a structure for a wide-mouth plastic container that can be stacked efficiently, one on top of the other, with similar containers and that can be produced by means of high speed manufacturing equipment in a manner economic that ensures consistent quality and performance. More specifically, the present invention provides a blow molded plastic container having a base with a continuous or discontinuous concave outer ring wall having an outer portion and an inner portion forming a vertical ring therebetween. an inner annular wall that extends into the external annular wall and above the vertical ring.The inner periphery of the inner annular wall is made of blow molded plastic material that is fixed with heat and biaxially oriented and connects with a central dimple of Functionally, the inner annular wall is capable of flexing up and down in response to variations in pressures in a filled and sealed container without undergoing undesired permanent deformation.In addition, preferably a shoulder extends radially. inward in the inner portion of the outer annular wall above a level of the vertical ring to facilitate the vertical stacking of containers that have similar bases. In a particular embodiment, the container includes a body having an integrally formed base including an annular cava wall extending from a side wall of the container to a vertical surface, an internal wall that is substantially perpendicular to the side wall and extends from the vertical surface to a substantially planar internal annular wall. The annular wall with cava can be continuous. A dimple is centrally located in the inner annular wall and includes a plurality of marked ribs that extend radially apart. Each rib has a clamp that extends radially from the dimple and tapers to meet the inner annular wall. The ribs may also include a rib wall; and a clamp projection tapering from the rib wall to the inner annular wall. A clamp side wall extending from said clamp boss to said inner annular wall. The container can be made of a blow molded plastic material, and the degree of crystallinity of the plastic material in the base is greater than the degree of crystallinity of the plastic material in the side wall. The degree of crystallinity in the base may be greater than 20% and may be less than 30%. The diameter of the side wall can be no more than 50% more than the internal diameter of the vertical surface.

The inner annular wall of the base is adapted to flex up and down in response to variations in pressures within the container, when it is capped and filled, without undergoing undesired permanent deformation. The invention is also a method for improving the deformation resistance of the base in a blow molded plastic container comprising forming a concave annular wall extending from one end of the base to a vertical surface, forming an internal wall that extends from the vertical surface to a substantially planar internal annular wall that is substantially perpendicular to the side wall; and forming a dimple centrally positioned within the inner annular wall and a plurality of marked ribs extending radially apart, each of the ribs comprising a clamp extending radially from the dimple and tapering to meet the internal annular wall . BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects, aspects and advantages and other objects of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which: Figure 1 is a view in perspective of a container having a base according to an embodiment of the present invention. Figure 2 is an elevation view of the container illustrated in Figure 1. Fig. 3 is a bottom plan view of the base illustrated in Fig. 1. Figure 4 is a cross-sectional view of the base taken along the line IV-IV of Figure 3. Figure 5 is a cross-sectional view of the base taken along the line VV of the Figure 2 Illustrate a couple of containers in a stacked array. Figure 6 is a perspective view of a container having a base according to another embodiment of the invention. Fig. 7 is a bottom view of the aquarium base with the embodiment illustrated in Fig. 6. Fig. 8 is a cross-section of the base of Fig. 6, taken along the line V l -VNI of Figure 7; and Figure 9 is a cross section of the base of Figure 6, taken along line IX-IX of Figure 7. DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention is illustrated in the Figures 1 to 5 as a container 1 00. The container 1 00 has a base 1 1 2, a side wall 1 14 tubular and a threaded finish 1 16 wide mouth which projects from the upper end of the side wall 1 4 via one shoulder 1 1 8. In the illustrated mode, upper and lower label stops, 1 20 and 1 22, are placed adjacent to the shoulder 1 1 8 and the base 1 12, respectively, and delineate a substantially cylindrical label area 124 on the side wall 1 14. The containers according to the invention may have different cross-sectional shapes than the circular one. In addition, the side wall 1 1 4 can have a series of circumferential notches 1 26 which reinforce the side wall 1 14 and resist paneling, marks and other undesirable deformations of the side wall 1 1 4. The container 1 00 is multi-functional since it can be used in hot filling processes as well as pasteurization and retort. To accomplish this goal, the base 12 has a structure that is capable of accommodating the high internal pressure of the container experienced during pasteurization or retort processing, and which is capable of accommodating reduced volume and pressure of the container experienced upon cooling a container. filled and sealed after hot filling, pasteurization or retort processing. For this purpose, the base 1 12 can be flexed downward in a controlled manner and to a desired degree when the pressure inside the filled and sealed container rises, and the base 1 12 can be flexed upward in a controlled manner and up to a desired degree when a vacuum develops inside the filled and sealed container. Structurally, base 1 12 includes a concave external annular wall 128 that is either continuous or discontinuous. Figures 1 to 5 illustrate one embodiment of the base 1 12 having a discontinuous concave external annular wall 128 that provides a plurality of arcuate supports 1, spaced apart adjacent the outer periphery 132 of the base 1 1 2. Each support 1 30 it has an outer wall portion 1 34 that extends upward to the lower label stop 122 and an inner wall portion 1 36 that extends upward and inward towards the remaining base structure as will be discussed. A vertical surface 1 38 is formed at the junction of each of the outer and inner wall portions, 1 34 and 1 36, whereby a discontinuous support ring of the container 1 00 is formed. Figures 6 to 9 illustrate an embodiment of a base 212 having an annular continuous concave outer wall 228 that forms a vertical surface 238, as more fully described below. An inner annular wall 140 of the base 1 12 extends into the outer annular wall 128. The inner annular wall 140 has an outer periphery 1 42 and an internal periphery 1 44. The outer periphery 142 of the internal annular wall 144 its rge with the inner wall portion 1 36 of each of the supports 1 30 and, in the illustrated embodiment, with a plurality of radial, horizontally disposed, separate networks 146 located adjacent to each other. the outer periphery 1 32 of the base 1 1 2. Each of the networks 1 46 extends between the supports 130 and connects with the side wall 1 14 of the container at an elevation above the horizontal plane "P" extending to through vertical surface 138. In an embodiment of the present invention in which the concave external annular wall 128 is continuous, networks 146 are not provided. The inner periphery 144 of the internal annular wall 1 40 emerges towards an anti-inversion central dimple 148. The internal annular wall 140 functions as a flexible panel.

For this purpose, when the internal pressure inside a sealed and filled container increases, the inner ring wall 140 flexes downwards to accommodate the increased pressure and prevent the side wall 14 of the container 100 from suffering permanent undesirable distortion. In addition, the inner annular wall 140 flexes upward to relieve vacuum when the contents of a hot filled and capped container, or a filled, capped and pasteurized container subsequently, are cooled to room temperature. Thus, when the sealed container and the contents are cooled to room temperature, the side wall 14 remains substantially unchanged from its shape as it was initially formed and is capable of perfectly supporting a rolled-up label around without undesirable voids or the like underneath it. label. In addition, the side wall 1 14 resists ovalization and the base 1 12 provides a level seating surface that is not subject to oscillation or the like. The base 1 12 of the container 100 is specifically designed to provide bending movement. Increasing the flexure of the base 12 is accomplished by providing a larger circular plane between the dimple 148 and the arched supports 130. Thus, the inner annular wall 140 of the container 100 is relatively large compared to other containers of a similar size. For this purpose, the diameter, size or extent of the dimple center 148 is reduced and the internal diameter of the arched supports 130 increases with respect to the containers of the prior art.

The relatively large flat surface provided by the internal annular wall 140 provides greater flexure; however, it may also be more prone to "stretching", i.e., permanently deforming in an outward projecting position when its contents are hot filled or heated to relatively high temperatures, such as those encountered during pasteurization processing or retort. This is because a ring of amorphous material is created in the interconnection of the inner periphery 144 of the internal annular wall 140 and the dimple 148 due to! reduced size of the dimple 148. This ring of non-oriented material, which is not fixed by heat provides a weakened area that allows the base to "stretch" when filled and sealed with contents at elevated temperatures. The base 1 12 of the present invention overcomes the problem of "stretching" by providing a series of spaced, radially spaced, spaced apart ribs 150 in the dimple 148 where the inner periphery 144 of the internal annular wall 140 interconnects with dimple 148 central. The structure provided by the ribs 150 causes the material in this region to stretch during the blow molding of the container 100 so that the ring of material adjacent the interconnect of the dentition 148 and the inner annular wall 140 is fixed by heat and the extension of the biaxial orientation is increased to structurally reinforce the base and prevent "stretching" of the base 1 12. If desired, the dimple 148 can be marked to a given degree in the container 100 to provide additional stretching, and the number total of ribs 1 50 may be three or more, such as 6, as illustrated in Figure 1. In addition, the shape and size of the ribs may vary provided that the blow molded plastic material forming the base in the interconnection of the dimple 148 and the internal annular wall 140 has sufficiently increased biaxial orientation and is heat set by heated surfaces. of a blow mold. Thus, the inner annular wall 140 flexes downwards when the container is filled, capped and subjected to an increase in pressure inside the container. However, complete inversion and failure are prevented by the reinforcement ribs 150 formed in the dimple 148, which travels with the inner annular wall 140. Ribs 150 and dimple 148 maintain a substantially constant shape regardless of the internal pressure experienced within the container, due to the increases in density and rigidity resulting from the increased orientation. Another aspect of the base 1 12 of the present invention is that each inner wall portion 136 of the arched supports may have an arched shoulder 156, or support ridge, formed therein and spaced in elevation from both the support surfaces 138 as of the internal annular wall 140 to facilitate vertical stacking of similar containers 100. For example, as illustrated in Figure 5, a top container 100a can be stacked in a lower container 100b. The support ridge 156 on the base 1 12a of the upper container 100a sits on the outer edge 158 of the upper surface 160 of the lid 162 of the lower container 100b so that the horizontal plane "Pa" extending through vertical surfaces 138a of the upper container 100a extend a distance apart beyond the upper surface 160 of the lid 1 62 of the lower container 100b. By way of example, and not by way of limitation, the container 100, according to the present invention, preferably has a height "H" of approximately 14,732 centimeters, a diameter "D" more external of the container of approximately 10,668 centimeters, and can have a capacity of approximately 907.2 grams. The discontinuous vertical ring, formed by the vertical surfaces 38, has a diameter of approximately 9,398 centimeters, and the internal annular wall 140 of the base 1 12 has an internal periphery 144 with a diameter of less than about 3,175 centimeters and an outer periphery 142 with a diameter of at least about 6.35 centimeters. The radial networks 146 are evenly separated and separate each support 130 so that each support 130 is at least about 0.8 radians. In addition, each support 130 has an arched extension larger than that of each radial network 146. Figures 6 to 9 illustrating a second embodiment of a base 212 that can be used in a container 200 in accordance with the present invention. Except for the base 212, the container 200 can be the same as or different from the container 100. Accordingly, the last two digits in the reference numbers used to designate the aspects of the container 200 are the same as the reference numbers that they are used to designate the related aspects of the container 100. For example, the container 200 may include a threaded finish 216 which may be the same as the threaded finish 1 of the first embodiment, and may accommodate a closure 262 having complementary threads. Similarly, the shoulder 21 8, the upper stop 220, the circumferential notches 226, the label area 224 and the side wall 214 can be structurally similar to the corresponding aspects of the first embodiment. The second embodiment of the base 212 includes an annular side wall 228, external, concave, continuous. The external portion 228 of the annular side wall curves from the side wall 214 toward the center of the container 200 to form a vertical, continuous surface 238. The vertical surface 238 is formed as a circular, continuous surface. In addition, the transition from the outer annular side wall 228 to the vertical surface 238 is gradual and continuous. An inner portion 236 of the outer annular side wall extends from the vertical surface 238 to an internal, substantially planar annular wall 240. The outer periphery 242 of the inner, annular wall 240 forms a continuous ring around the annular wall 240, internal. Positioned approximately centrally on annular wall 240, there is a dimple 248. Extending outwardly from dimple 248 there is a series of ribs 250. Dimple 248 of this embodiment can be substantially the same size as dimple 148 of the first dimple. modality 100, or it can be slightly larger. The ribs 250 of the second embodiment extend outwardly to form a series of clamps 270 positioned radially, which tapers to an elevation that reaches the annular wall 240, internal, flat, before, near, or at the outer periphery 242 of the annular, internal wall. In the illustrated embodiment, the ribs 250 extend first outwardly from the dimple to a depth similar to the internal portion 272 of the dimple to a rib wall 274, where there is a relatively abrupt change in depth toward the inner annular wall 240. The rib wall 274 extends to a clamp protrusion 276 which slopes toward the surface of the annular, inner wall 240. The clamp protrusion 276 may be joined to the surface of the annular, internal wall 240 at or before the outer periphery 242. The side wall of the clamp 278 extends upwardly from the clamp boss 276 to the surface of the inner annular wall 240. The clamp side wall 278 is joined to the annular wall 240, internal to a periphery of the clamp 270. The side wall of the clamp 278 may be substantially perpendicular to the inner annular wall 240 and the clamp projection 276. The annular wall 240, internal to the base 2f2, flexes analogously to the annular, inner wall 140 of the base 1 12. The radially spaced clamps 270 further control the bending of the annular wall 240 in response to the reduced pressures they occur when cooled during hot fill processing, and the reduced and increased pressures that occur during pasteurization and retort processing. The presence of the clamps 270 allows greater flexion of the annular wall 240, internal to the annular, external concave wall 228 without allowing the permanent deformation of the base. In addition, the presence of a continuous external annular wall 228 is useful during the stringent conditions of pasteurization and retort. Under such conditions, a discontinuous side wall having legs may have a tendency for the legs to pull inwardly, causing the lower stop to move into a square shape. Having a continuous vertical surface 238 and an annular, external, continuous side wall 228 and an annular, external, continuous lateral wall 228, this tendency is reduced. In addition, the presence of a vertical, continuous surface 238 relieves any tendency for excessive stretching. The structure of the base described herein is illustrated with a support crest 156 (see Figures 1 to 5) for stacking the containers. Such a ridge or shoulder, however, can easily be incorporated into a base 242 according to this second embodiment of the invention. Base 212 according to the present invention, preferably, is crystallized to such a degree as previously described in the first embodiment. Some degree of bistaxity and biaxial orientation is usually achieved during the blow molding process. Crystallization can also be promoted by heat setting the container. For example, the walls and base of the mold can be maintained at an elevated temperature to promote crystallization. When the container is heat set at a temperature of about 82.2 ° C, the side walls, base, dome and threads of the container can typically be crystallized up to about 20%. This degree of crystallinity is typical for a blow molding process and does not represent a significant amount of heat setting or increased crystallinity or orientation, as compared to a typically prepared container. However, the properties of the base of the present invention can be advantageously increased by heat setting the container, and particularly the base, at even higher temperatures. Such temperatures can be, for example, greater than 121 .1 and can be 162.7 or even higher. When these high heat setting temperatures are used, the crystallinity can be increased to more than 20% or 25% or more. A disadvantage of increasing the crystallinity and the biaxial orientation in a plastic container is that this process introduces opacity in the normally clear material. However, non-similar bases in containers of the prior art designed for use in pasteurization and retort processes, which may require a crystallinity of 30% or more, using crystallinity as low as 22 to 25% with a base structure of In accordance with the present invention, they can achieve significant structural integrity, while maintaining the substantial clarity of a base that is preferred by manufacturers, packers and consumers of such pasteurized products. Cristallities of 30% or more that are frequently used in previous containers to achieve significant structural integrity can cause undesirable opacity in the base region. Bases formed with configurations in accordance with the present invention provide a more attractive structure for consumers, packers and manufacturers for other reasons, as well. For example, when changing from the use of glass to plastic in the packaging of such pasteurizable products, the design changes cause undesirable changes in the internal configuration of the container. Typically, in order to withstand the rigors of pasteurization or retort processing, the above containers have a base formed with a large central top push, as used in typical plastic containers used in hot filling processes. This upward or upward thrust limits the volume of material that can be placed in the container in the inner region between the push up and the side walls. This can be particularly problematic when packing solid products, for example, pickles. The presence of narrow channels that form between the side wall and the large upward thrust of the base in the internal space of a typical blow molded container may limit the volume at which solid materials may be placed. That is, such designs create dead space inside the container that can be filled with liquid, but not with the solid product. In traditional glass containers, a relatively flat bottom can be formed which allows solids to be packed throughout the vertical and radial extent of the container. The prior art plastic containers that have been used to withstand pasteurization and retort conditions have used a similar internal geometry, which creates dead space. In accordance with the present invention, and particularly in accordance with the second embodiment described herein, the configuration of the base can reduce the amount of dead space and be much more similar to traditionally used glass containers. For example, the inner, substantially planar annular wall 240 may extend to an extent substantially out toward the edge of the container. Using a base configuration according to the present invention, the inner diameter of the vertical surface, ie, the push region above the base Di, as shown in Figure 9, can be a relatively large portion of the diameter D2 of the container. According to the present invention, the ratio of the diameter D2 of the container to the push-up diameter D-i may be less than 1.5: 1.0 and still 1.3: 1.0 or less. Established differently, the diameter of the container D2 may be less than 50% larger than, or as small as approximately 30% larger than, the diameter of D-i of the push region above. In cases where the container is not round, this corresponds to a projected volume of the side wall region less than 70% more than the projected area of the push region above. As an example, and not by way of limitation, the container 200 according to the present invention may have dimensions similar to those of container 100. For example, the container may have a height of approximately 14.73 centimeters, or an external D2 diameter of approximately 9.65 centimeters, and may have a capacity of approximately 907.2 grams. . The push region above the base can have a Di diameter of approximately 7.87 centimeters. The clamp 270 may have a clamp protrusion 276 extending out approximately 1.524 centimeters from the dimple 248. The distance between the opposing rib walls 274 may be approximately 1.2 centimeters, while the distance through the dimple. 248 in the region between the ribs can be approximately 2,286 centimeters. Containers 100 and 200 may be blow molded from an injection molded preform made of, for example, PET, PEN or mixtures thereof, or may be blown-extrusion molded plastic, eg, polypropylene (PP) . In addition, containers 100 and 200 can be multi-layer, including a layer of gas barrier material or a layer of chip material. The resins also include modified polyester resins to improve UV resistance, for example, Heatwave ™ CF246, available from Voridian (Kingsport, Tennessee, E.U.A). The finishes of the containers can be injection molded, ie, the threaded portion can be formed as part of the preform, or can be blow molded and can be cut from an accommodation feature formed therein, as is known in the art. The containers 1 00 and 200 described above are capable of use, for example, in hot filling operations having filling temperatures up to about 96.1 ° C. As explained above, containers 1 00 and 200 have bases 1 1 2 and 21 2 that can be used when processed at temperatures close to or in excess of 96.1 ° C. The containers can also be used in typical pasteurization processes used in the packaging technique. In an example process, a cold solid product, such as pickles, is combined with brine moderately heated from 48.8 to 60 ° C inside the container. After the container is covered, the full container can be processed through a pasteurization tank, where temperatures approach approximately 100 ° C, so that the solid products in the sealed container are heated to approximately 79.4 ° C for 15 minutes before the filled and sealed container is cooled to room temperature. Although preferred containers and base structures have been described in detail, various modifications, alterations and changes can be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims (23)

1. CLAIMS 1. A container comprising: a blow molded plastic body having an integrally formed base, said base comprising: an annular, external, concave wall having an internal portion extending from a side wall of the container to a vertical surface and an external portion extending from the vertical surface to an internal, substantially flat, annular wall that is substantially perpendicular to the side wall; and said annular, internal wall having an internal periphery which is connected to a central dimple, anti- inversion projecting from said internal periphery of said annular, internal wall; said annular, internal wall of said base that flexes up and down in response to variations in pressure inside the container, when it is capped and filled, without experiencing any undesired permanent formation.
2. 2. The container according to claim 1, wherein said internal periphery is made of blow molded plastic material which is at least partially fixed by heat and biaxially oriented.
3. 3. A container according to claim 2, wherein said outer, concave, annular wall is continuous. A container according to claim 2, wherein said annular, external, concave wall is discontinuous. The container according to claim 4, wherein said annular, internal wall connects with said inner portion of said annular wall, concave at an outer periphery, said outer periphery having a plurality of radial networks extending outwardly. at an elevation above said vertical ring. 6. A container according to claim 2, wherein said central dimple includes a marked, substantially circular surface having marked hollow ribs formed therein. 7. A container according to claim 2, further comprising a plurality of spaced, radially extending ribs marked on said base where said inner periphery of said central annular wall interconnects with said central dimple. The container according to claim 1, wherein said dimple comprises a plurality of spaced, radially spaced, spaced ribs, each of said ribs comprising a clamp extending radially from said dimple and tapering towards said annular, internal wall. A container according to claim 2, wherein said annular, concave wall is continuous. 0. The container according to claim 8, said ribs further comprising a rib wall; and a clamp projection tapering from said rib wall towards the inner annular wall. eleven . The container according to claim 10, further comprising a clamp side wall extending from said clamp projection to said inner, annular wall. 12. The container according to claim 8, wherein the container comprises a plastic material blow molded and wherein a degree of crystallinity of the plastic material in the base is greater than a degree of crystallinity of the plastic material in the side wall . The container according to claim 12, wherein the degree of crystallinity in the base is greater than 20%. 14. The container according to claim 12, wherein the degree of crystallinity in the base is greater than 30%. The container according to claim 8, wherein the diameter of the side wall is not more than 50% greater than the internal diameter of the vertical surface. The container according to claim 8, wherein said container and base are made of PET, wherein the side wall has a diameter of approximately 9,652 centimeters, and the diameter of the vertical wall is approximately 7,874 centimeters. 17. The container according to claim 8, wherein said clamp tapers to find said annular, internal wall. A container according to claim 1, wherein said inner portion of said outer, annular wall has a support ridge formed therein above a level of said vertical surface of the container to facilitate vertical stacking of containers that have similar bases. 9. A container according to claim 1, wherein said vertical ring has a diameter of at least about 9,398 centimeters, and said internal periphery of said central, annular wall is less than about 3,175 centimeters. 20. A container according to claim 1, further comprising a thin-walled body extending upwardly from said annular, external wall and having a wide-mouth threaded finish blown at an upper end of said body. twenty-one . A container according to claim 1, wherein said base is substantially circular and said side wall is substantially circular. 22. A container according to claim 1, said side wall comprising a substantially cylindrical label panel having a plurality of circumferential, longitudinally spaced reinforcement notches delineated by an upper and lower label stop. 23. A method for improving the deformation resistance of the base in a blow molded plastic container, comprising: forming a concave annular wall extending from one end of the base to a vertical surface; forming an inner wall extending from the vertical surface to an internal, substantially flat, annular wall that is substantially perpendicular to the side wall; and forming a dimple centrally positioned in said inner, annular wall and a plurality of spaced, radially spaced, spaced ribs, each of said ribs comprising a clamp extending radially from said dimple and tapering towards said wall annular, internal.