Hot-fillable and retortable plastic container   

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to the field of containers used with food products. In particular the field of the invention is directed to hot-fillable, retortable and/or pasterurizable plastic containers.

2. Description of the Related Technology

Plastic blow-molded containers, particularly those molded of PET, have been utilized in hot-fill applications where the container is filled with a liquid product heated to a temperature in excess of 180° F. (82° C.), capped immediately after filling, and allowed to cool to ambient temperatures. Plastic blow-molded containers have also been utilized in pasteurization and retort processes, where a filled and sealed container is subjected to thermal processing and is then cooled to ambient temperatures.

Pasteurization and retort methods are frequently used for sterilizing solid or semi-solid food products, e.g., pickles and sauerkraut. The products may be packed into the container along with a liquid at a temperature less than 82° C. (180° F.) and then sealed and capped, or the product may be placed in the container that is then filled with liquid, which may have been previously heated, and the entire contents of the sealed and capped container are subsequently heated to a higher temperature. As used herein, “high-temperature” pasteurization and retort are sterilization processes in which the product is exposed to temperatures greater than about 80° C.

Pasteurization and retort differ from hot-fill processing by including heating the filled container to a specified temperature, typically greater than 93° C. (200° F.), until the contents of the filled container reach a specified temperature, for example 80° C. (175° F.), for a predetermined length of time. That is, the external temperature of the hot-filled container may be greater than 93° C. so that the internal temperature of a solid or semi-solid product reaches approximately 80° C. Retort processes may also involve applying overpressure to the container.

Plastic containers have replaced or provided an alternative to glass containers for many applications. However, few 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. For example, during a retort process, when a plastic container is subjected to relatively high temperatures and pressures, the plastic container\'s shape will distort. Upon cooling, the plastic container generally retains this distorted shape or at least fails to return to its pre-retort shape. Accordingly, 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 realized through manufacture and recycling. The lighter weight of plastic containers as compared to glass can also advantageously reduce shipping costs.

Much like glass containers, the usage of metal containers instead of plastic containers has many disadvantages. Metal containers may be more expensive to produce and the metal containers may ultimately weigh more during shipping. Furthermore, metal containers may dent or be damaged during shipping. Therefore, the usage of plastic in place of metal would also provide a benefit for producers of food products that typically use metal containers.

While using plastic containers is advantageous in the long run. The difficulty in producing such a container that also retains the look and shape of a container that has traditionally held the type of contents to be stored has proven difficult to achieve. Therefore there is a need in the field to produce a container that is able to capture the aesthetic and traditional look of a standard metal container, such as aluminum cans, while being able to utilize the benefits of plastic.

SUMMARY

An object of the present invention is a plastic container having a double seam structure.

Another object of the present invention is a plastic container having hoops located in the body portion.

Still yet another object of the present invention is a container having the appearance of a metallic can.

Another object of the present invention is a container adapted for hot-filling, a retort process and/or pasteurization.

An aspect of the present invention may be a plastic container comprising: a body portion constructed of a plastic material and comprising a hoop; a base portion located below the body portion; and a top portion located above the body portion, wherein the top portion comprises a double seam structure.

Yet another aspect of the present invention may be a plastic container comprising: a body portion constructed of a plastic material; a base portion located below the body portion; a top portion located above the body portion; and wherein the body portion comprises a plurality of hoops.

Still yet another aspect of the present invention may be a plastic container comprising: a top portion adapted for accommodating a closure used with double seam structures; a body portion located below the top portion, wherein the body portion comprises; a shoulder portion; a first body segment located below the shoulder portion; a first hoop located below the first body segment; a second body segment located below the first hoop; a second hoop located below the second body segment, wherein a height of the first body segment taken from the shoulder portion to the first hoop is greater than the height of the second body segment taken from the first hoop to the second hoop; and a base located below the body portion.

These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a container, in accordance with an embodiment of the present invention.

FIG. 2 is a front view of the container.

FIG. 3 is expanded view of a section of the container shown in FIG. 2.

FIG. 4 is a cross-sectional view of the container taken along line 4-4 shown in FIG. 2.

FIG. 5 is a bottom view of the container shown in FIG. 1

FIG. 6 it a top down view of a double seam container closure.

FIG. 7 is a cross-sectional view of the double seam container closure taken along line 7-7 shown in FIG. 6.

FIG. 8 is a flow chart showing the steps in the process of hot-filling, undergoing a retort process and/or pasteurizing the container.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and now referring in particular to FIGS. 1 and 2 showing an isometric and front view of the container 10.

The container 10 may be a one-piece construction and may be prepared from a monolayer plastic material, such as a polyamide, for example, nylon; a polyolefin such as polyethylene, for example, low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, a polyester, for example, polyethylene terephthalate (PET), polyethylene naphtalate (PEN), or others, which may also include additives to vary the physical or chemical properties of the material. For example, some plastic resins may be modified to improve the oxygen permeability. Alternatively, the container may be prepared from a multilayer plastic material. The layers may be any plastic material, including virgin, recycled and reground material. The layers may include plastics or other materials with additives to improve physical properties of the container. In addition to the above-mentioned materials, other materials often used in multilayer plastic containers may be used including, for example, ethylvinyl alcohol (EVOH) and tie layers or binders to hold together materials that are subject to delamination when used in adjacent layers. A coating may be applied over the monolayer or multilayer material to introduce oxygen barrier properties. In an exemplary embodiment, the present container is prepared from PET.

The container 10 is constructed to withstand the rigors of hot-fill processing, a retort process and/or pasteurization. The container 10 may be made by conventional blow molding processes including, for example, extrusion blow molding, stretch blow molding and injection blow molding. These molding processes are discussed briefly below.

In extrusion blow molding, a molten tube of thermoplastic material, or plastic parison, is extruded between a pair of open blow mold halves. The blow mold halves close about the parison and cooperate to provide a cavity into which the parison is blown to form the container 10. As so formed, container 10 may include extra material, or flash, at the region where the molds come together. A moil may be intentionally present above the top portion of the container.

After the mold halves open, the container 10 drops out and is then sent to a trimmer or cutter where any flash of moil attached to the container 10 is removed. The finished container 10 may have a visible ridge (not shown) formed where the two mold halves used to form the container came together. This ridge is often referred to as the parting line.

With stretch blow molding a preformed parison, or pre-form, is prepared from a thermoplastic material, typically by an injection molding process. The pre-form typically includes an opened end, which becomes part of the closure of the container 10. The pre-form is positioned between two open blow mold halves. The blow mold halves close about the pre-form and cooperate to provide a cavity into which the pre-form is blown to form the container 10. After molding, the mold halves open to release the container 10.

With injection blow molding, a thermoplastic material may be extruded through a rod into an injection mold in order to form a parison. The parison is then positioned between two open blow mold halves. The blow mold halves close about the parison and cooperate to provide a cavity into which the parison may be blown to form the container 10. After molding, the mold halves open to release the container 10.

As discussed above, the plastic blow-molded containers, particularly those molded of PET, are utilized in hot-fill applications, retort processes and/or pasteurization. Hot-filling involves filling the container 10 with a liquid product heated to a temperature in excess of 180° F. (i.e., 82° C.), capped immediately after filling, and then allowed to cool to ambient temperatures. Pasteurization and retort differ from hot-fill processing by including heating the filled container to a specified temperature, typically greater than 93° C. (200° F.), until the contents of the filled container reach a specified temperature, for example 80° C. (175° F.), for a predetermined length of time. That is, the external temperature of the hot-filled container may be greater than 93° C. so that the internal temperature of a solid or semi-solid product reaches approximately 80° C. Retort processes may also involve applying overpressure to the container

In the construction of containers it is important to keep the container\'s top load and hot-fill, retort and pasteurization performance characteristics strong. The structural integrity of the container must be maintained after the hot-fill, pasteurization and/or retort process. Furthermore, consideration must be made for preventing bulging of the container 10 that can occur with some containers. When a container 10 is said to be adapted for a hot-fill process, retort process and/or pasteurization process, it is meant that the container 10 is designed and structured so as to withstand the heating and/or over pressuring that are involved in these processes without undergoing significant structural deformation.

Referring to FIGS. 1-5, a cylindrical shaped container 10 is shown that is similar in appearance to a traditional can. Referring to FIG. 1, the container 10 has a plurality of hoops 17(a)-17(c) and a top portion 25, which is a double seam structure adapted to receive a double seam container closure, also known as a can end. The container 10 may be used, for example, metal can replacement.

The container 10 has a top portion 25 that forms a double seam structure, which is shown in more detail in FIG. 2. A central axis A runs through the center of the container 10. The top portion 25 has an opening 16 through which contents are placed. The top portion 25 also comprises the upper seam structure 19 and the lower seam structure 18 that forms the double seam structure. The upper seam structure 19 and the lower seam structure 18 together have a height H1 that is adapted for receipt of a double seam container closure. The height H1 is taken from the opening 16 to the top of the bumper portion 13. In the embodiment shown in FIGS. 1-5 the upper seam structure 19 and the lower seam structure 18 are circular in shape.

Located below the lower seam structure 18 is the bumper portion 13 comprising a shoulder portion 27 that merges into the body portion 30 of the container 10. The shoulder portion 27 provides a smooth transition between the bumper 13 and the body portion 30. The height H2 of the bumper portion 13 may be less than the height H1 of the top portion 25, however it should be understood that the height H2 of the bumper portion 13 may vary depending on the aesthetic design of the container 10. In the embodiment shown in FIGS. 1-5, the bumper portion 13 is circular in shape. The bumper portion 13 is adapted to contact the machinery used to grip the containers 10 used during the line processes, the bumper portion 13 cooperates with base portion 12 in order to accomplish this task. The bumper portion 13 also provides protection for the label placed on the container 10.

Body portion 30 comprises a plurality of body segments 14(a), 14(b), 15(a), 15(b) and hoops 17(a)-17(c). The body segments 14(a), 14(b), 15(a) and 15(c), shown in FIGS. 1-4 are circular in shape. Interspersed between the body segments 14(a), 14(b), 15(a) and 15(c) are hoops 17(a)-17(c).

The container 10 shown in FIGS. 1 and 2 has a first body segment 15(a) having a height H3, which is taken from the bottom of the shoulder portion 27 to the top of the hoop 17(a). Located below the first body segment 15(a) is the hoop 17(a). Located below the hoop 17(a) is a second body segment 14(a) that has a height H4 which is the distance between the hoops 17(a) and 17(b) that are above and below the second body segment 14(a), and is measured from hoop 17(a) above the second body segment 14(a) to the hoop 17(b) below the second body segment 14(a). In the embodiment shown in FIG. 1, the height H3 is greater than the height H4. Located below the second body segment 14(a) is another body segment 14(b) that has a height H5 that is substantially the same as the height H4 and is the distance between the hoop 17(b) to the hoop 17(c). Below the body segment 14(b) is the hoop 17(c). The body segment 15(b) is located above the shoulder portion 29 and has a height H6 which is taken from the hoop 17(c) to the top of the shoulder portion 29. The height H6 of the body segment 15(b) is substantially the same as the height H3 of body segment 15(a).

In the embodiment shown in FIGS. 1-5 there are three hoops 17(a)-17(c) shown, however there may be more or less hoops 17 used in alternative embodiments depending upon the size of the finished container 10. It should be understood that the number and types of body segments may vary depending on the aesthetic requirements of the container 10. For example, more hoops 17 may be present in the body portion 30 and therefore there may be more body segments having the heights of body segments 14(a) and 14(b). Preferably the heights of the body segments, such as body segments 15(a) and 15(b) that merge with the shoulder portions 27, 29 are greater than the heights of the body segments that lie within the central portion of the body portion 30.

The hoops 17 further assist in accommodating the stresses that the container 10 may undergo due to hot-filling, retort processes and/or pasteurization processes, such as internal negative pressure. They also assist in preventing buckling, ovalization and reduction of structural integrity that may be a result of these processes. While the hoops 17 shown are circular in shape, it should be understood that other shapes are permissible, however they may not provide as much structural support for the container 10 during a hot-fill process, a retort process and/or a pasteurization process.

Still referring to FIGS. 1 and 2, located below the body portion 30 is the base portion 12, which comprises the shoulder portion 29 and the bottom portion 20. The shoulder portion 29 smoothly merges the base portion 12 into the body portion 30. The base portion 12 cooperates with the bumper portion 13 in providing contact points for the machinery used to grip the containers 10 used during the line processes.

Now turning to FIG. 3, wherein a close up view of the top portion 25 is shown. Upper seam portion 19 is located above lower seam portion 18. Merge segment 11 smoothly merges the upper seam portion 19 into the lower seam portion 18. Between the opening 16 of the container 10 and the upper seam portion 19 is the angled edge 22. The angled edge 22 is angled with respect to the horizontal H, which is perpendicular to the central axis A. In the embodiment shown in FIG. 3 the range of the angle θ may be between 5-20° and more preferably between 10-18°, and still more preferably approximately 14-16°. The angled edge 22 is adapted to receive and facilitate securing a double seam container closure 40, shown in FIG. 5, which is typically used in the construction of metal cans. During the placement of the double seam container closure 40 the angled edge 22 is folded over.

FIG. 4 shows a cross-sectional view of the container 10 shown in FIG. 2. Illustrated in FIG. 4 are the distances of the interior surfaces of the container 10 from the central axis A and in a cylindrical shaped container 10, the distances represented by the L1-L12 represent the radii at these locations.

The length L1 is taken from the central axis A to the angled edge 22. The closure that is placed on the container 10 is typically of greater length than the length L1. The length L2 is taken from the central axis A to the interior wall of the upper seam portion 19. The length L2 is typically less than the length L1. The length L3 is taken from the central axis A to the interior wall of the lower seam portion 18 and is typically less than the length L2.

The length L4 is taken from the central axis A to the interior wall of the bumper portion 13. The length L4 is similar to the length L12. The length L12 is taken from the central axis A to the interior wall of the base 12. The lengths L4 and L12 are typically greater than any other lengths of the container 10. These provide the furthest distances from the central axis A so to provide contact points on the fill line.

The lengths L5, L7, L9 and L11 of are taken from the central axis A to the respective sides of body segments 15(a), 14(a), 14(b) and 15(b) respectively. The lengths L5, L7, L9 and L11 are all substantially equal to each other and provide a uniform distance from the central axis A so as to provide a level surface to enable the placement of a label.

The lengths L6, L8 and L10 are taken from the central axis A to the respective sides of hoops 17(a)-17(c). The lengths L6, L8 and L10 are less than lengths L5, L7, L9 and L11. Additionally the lengths L6, L8 and L10 may substantially be the same length as L3 of the lower seam portion 18. The similarity in lengths between L6, L8 and L10 and L3 assist in providing additional strength to the overall structure of the container 10.

Referring to FIG. 5, a bottom portion 20 of the container 10 is shown. The bottom portion 20 illustrates the cylindrical nature of the container 10.

FIG. 6 is a top down view of the double seam container closure 40. The double seam container closure 40 is secured to the container 10 through the usage of the double seam structure, comprising the upper seam portion 19 and lower seam portion 18, shown in FIGS. 1-4 The container closure 40 may be made of metal, such as steel or aluminum. It may be possible to construct the container closure of a plastic material, provided the closure 40 can withstand the rigors of a hot-fill process, a retort process and/or a pasteurization process.

FIG. 7 is a cross-sectional view of the double seam container closure 40 taken along line 7-7. Additionally shown in FIG. 7 are the closure tabs 42 which are used to engage the double seam structure on the container 40.

FIG. 8 is a flow chart showing the steps in the process of hot-filling, undergoing a retort process and/or pasteurizing the container 10. In step 102, the container 10 is provided. In step 104 the container 10 is gripped at the bumper portion 13 and base portion 12. In step 106, the container 10 undergoes hot-filling, a retort process and/or a pasteurization process of the contents of the container 10. It is to be understood that when a retort process is performed and/or a pasteurization process is performed the container 10 is first filled with the contents. In step 108, a double seam container closure 40 is placed on the double seam structure located at the top portion 25 of the container 10.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.