Container with sealable finish

Abstract

A container having a neck and a finish merging with said neck. The finish includes a first lip connected to said neck, a second lip spaced apart from said first lip in a direction that is substantially perpendicular to said first lip, and a curved portion connecting said first lip with said second lip.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a finish for a plastic container, and more particularly to a finish for a plastic container for accepting a thermosealed lid.

2. Related Art

Thermosealed containers, such as small polyolefin containers, may be used for packaging food, dairy, and other drinkable products. Such containers can be thermosealed at the opening in the neck with a suitable lid, for example, a foil lid. The lid is designed to be pulled off to allow access to the contents of the container. The contents can be, for example, drank directly from the container or, in the case of larger containers, spooned from the container. In designing such containers, the integrity of the lip of the container may be critical in obtaining a good seal. This is most commonly accomplished by increasing the thickness of the lip. Additionally, lip thickness may assist in improving the top-loading capabilities of the container. However, the lip of the container should not be so thick as to add unnecessary weight to the container. An additional problem that can arise when the lip thickness is reduced, is that the lip of the container may sink into the container during thermosealing, preventing a tight seal and resulting in product leakage from the container.

BRIEF SUMMARY OF THE INVENTION

Exemplary embodiments of the invention provide a container having a neck and a finish merging with said neck. The finish includes a first lip connected to said neck, a second lip spaced apart from the first lip in a direction that is substantially perpendicular to the first lip, and a curved portion connecting the first lip with the second lip.

Further exemplary embodiments of the invention provide method for sealing a container including providing a container having a neck, a finish merging with said neck, where the finish includes a first lip connected to the neck, a second lip spaced apart from the first lip in a direction that is substantially perpendicular to the first lip, and a curved portion connecting the first lip with the second lip, and thermosealing a lid to the container.

Still further exemplary embodiments of the invention provide a finish for a plastic container. The finish includes a first lip, a second lip spaced apart from the first lip in a direction that is substantially perpendicular to said first lip, and a curved portion connecting the first lip to the second lip.

Further objectives and advantages, as well as the structure and function of preferred embodiments will become apparent from a consideration of the description, drawings, and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.

FIG. 1 depicts an exemplary embodiment of a prior art container according to the present invention;

FIG. 2 depicts an exemplary embodiment of a prior art container according to the present invention;

FIG. 3a depicts an exemplary embodiment of a container according to the present invention before sealing;

FIG. 3b depicts an exemplary embodiment of a container according to the present invention after sealing.

FIG. 4a depicts an exemplary embodiment of a container according to the present invention before sealing; and

FIG. 4b depicts an exemplary embodiment of a container according to the present invention after sealing.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. All references cited herein are incorporated by reference as if each had been individually incorporated.

Exemplary embodiments of the present invention provide a thermosealable polyolefin container. Exemplary containers according to the present invention can include a very thin lip that is adapted for thermosealing at high sealing temperatures without undesirable deformation. In an exemplary embodiment of the invention, two lips of the neck of a container may stick together to give a strong resistance to lip deformation.

FIG. 1 depicts an embodiment of a prior art container 100 having a sealing lip 101 for receiving a thermosealed lid (not shown). Container 100 has a neck 102 that includes a neck flange 103 that merges with the sealing lip 101. When thermosealing container 100, sealing lip 101 must be thick enough so that the sealing temperature doesn't soften the plastic and cause the sealing lip 101 to sink into the container before foil sealing. When softening occurs, the top surface of the sealing lip 101 can bend and the edge 104 can curl into the interior of the container. As a result, the top surface, where the seal would be formed, is curved and thus has less surface area for bonding to the foil seal. As a result, the seal can fail resulting in a rejected container. To prevent the sealing lip 101 from sinking into container 100, the lip is typically 0.5 to 1.0 mm thick, for example. Such a thickness, however, results in an increase in the amount of plastic used to make the container, which, in turn, causes the container to be heavier and more expensive to construct.

The flange 103 serves several purposes in such a container. First, it provides a contact point for support on a filling line. Second, the flange provides top load strength for storing and stacking containers. However, the flange adds weight to the container that is not necessarily required for structural support of the container itself. Another disadvantage of the flange 103 is that it creates a concave inner surface in which the contained product can become entrapped during storage or use, or can be hard to remove when poured from the container.

FIG. 2 depicts an embodiment of a prior art container 200 having a sealing lip 201 and a neck 202 merging with sealing lip 201. Although the container 200 avoids the weight of an added flange, the design of the lip 201 and edge 204 suffers the same drawbacks as container 100 with lid 101 and edge 104. As similarly discussed above with respect to container 100, when thermosealing container 200, sealing lip 201 must be thick enough so that the sealing temperature doesn't soften the plastic and cause the sealing lip 201 to sink into the container before foil sealing. To prevent the sealing lip 121 from sinking into container 200, the lip must be, for example, 0.5 to 1.0 mm thick. Such a thickness, however, results in an increase in the amount of plastic used to make the container, which, in turn, causes the container to be heavier and more expensive to construct.

The sealing lips 101, 201 in these prior art containers suffer several drawbacks. For example, the edge 104, 204 can be relatively sharp, causing discomfort when a consumer drinks from the container. The sharpness of the edge 104, 204 can also be increased during the thermosealing process as the lip 101, 201 softens during sealing. Additionally, as previously mentioned, the edge 104, 204 of the lip 101, 201 can curl downward during thermosealing, resulting in an incompetent seal and a leaking container. Although making the lips thicker results in a more competent seal and less curling, it does not typically prevent sharpening of the edge 104, 204, and adds undesirable weight to the container. A finish having a lip according to the present invention avoids these and other drawbacks of known lips.

FIG. 3a depicts an exemplary embodiment of a thermosealable container 300 according to an embodiment of the present invention. Container 300 can have a finish 308 that includes an upper lip 301, a lower lip 302, a curved portion 303, a neck 304. Container 300 also includes a sidewall 305. As shown in FIG. 3a, neck 304 merges with sidewall 305; lower lip 302 merges with neck 304; curved portion 303 merges with lower lip 302; and upper lip 301 merges with curved portion 302. In such an embodiment, upper lip 301 and lower lip 302 are substantially horizontal such that the upper lip is spaced apart at a distance S from the lower lip in a direction that is substantially perpendicular to the lower lip. In an exemplary embodiment of the invention, upper lip and lower lip may be from 0.1 mm to 0.5 mm thick. In an exemplary embodiment of the invention, the distance S can be about 0.5 to 5.0 mm.

As shown in FIG. 3a, upper lip 301 has an edge 306 that may be a sharp edge prior to thermosealing container 300 with a foil seal, for example. Further, container 300 has a longitudinal axis A that extends substantially through the center of container 300. In an exemplary embodiment of the invention, neck 304 be located at a distance D₁, measured radially from longitudinal axis A and edge 306 can be located at a distance D₂ measured radially from longitudinal axis A. In such an embodiment, distance D₂ may be greater than or equal to D₁.

FIG. 3b depicts container 300 after it has been thermosealed. As shown in FIG. 3b, when heat is applied during thermosealing, the plastic softens and upper lip 301 can collapse towards lower lip 302. In an exemplary embodiment of the invention, edge 306 may contact lower lip 302, effectively removing the sharpness of edge 306 and creating a “soft” edge from the curve that connects the neck 304 with the lower lip 302. Because upper lip 301 and lower lip 302 are both substantially horizontal, when heat is applied during sealing, the degree to which the upper lip sinks into the container is limited by the lower lip 302. Instead of bending excessively, the upper lip 301 can contact lower lip 302 and, due to softening that occurs during sealing, the upper lip 301 and lower lip 302 can adhere to one another to give a strong lip resistance. Such a container may also provide a lightweight, thin lip that remains top-load resistant.

As shown in FIG. 3b, after thermosealing, the resulting sealed lip 301, 302 can have a substantially flat surface for sealing. Contrary to the prior art lips, which after thermosealing can have a curved surface, container 300 provides a flat surface 307 for thermosealing that provides more surface area for sealing the foil to the upper lip 301. In an exemplary embodiment of the invention, to create this flat surface 307, for example, heat may be applied during thermosealing reaches the finish of container 300, softening upper lip 301 and curved portion 303. When the upper lip 301 is heated during sealing, space S may act as an insulator between upper lip 301 and lower lip 302, so that lower lip 302 does not soften excessively, maintaining the integrity and structure of the lower lip and maintaining a substantially flat surface for accepting the seal. When this happens, upper lip 301 and curve 303 may collapse towards lower lip 302 and cause upper lip 301 to stick to lower lip 302.

The resulting container 300, as shown in FIG. 3b, provides other advantages over the prior art containers shown in FIGS. 1 and 2. For example, in container 300, no product becomes trapped because container 300 does not have a neck flange or some other welled area for trapping product. Additionally, the sharp edge is eliminated because edge 306 merges into lower lip 302, while at the same time, a flat surface 307 for thermosealing is maintained.

In a further exemplary embodiment of the invention, distance D₂ may be less than D₁. In such an embodiment, the upper lip of the container must be sufficiently bendable so as to prevent a sharp edge. FIG. 4a depicts an exemplary embodiment of a thermosealable container 400 according to an embodiment of the present invention. Container 400 can have a finish 408 that includes an upper lip 401, a lower lip 402, a curved portion 403, a neck 404. Container 400 also includes a sidewall 405. As shown in FIG. 4a, neck 404 merges with sidewall 405; lower lip 402 merges with neck 404; curved portion 403 merges with lower lip 402; and upper lip 401 merges with curved portion 402.

In such an embodiment, upper lip 401 and lower lip 402 are substantially horizontal such that the upper lip is spaced apart at a distance S from the lower lip in a direction that is substantially perpendicular to the lower lip. In an exemplary embodiment of the invention, upper lip and lower lip may be from 0.1 mm to 0.5 mm thick. In an exemplary embodiment of the invention, the distance S can be about 0.5 to 5.0 mm.

As shown in FIG. 4a, upper lip 401 has an edge 406 that may be a sharp edge prior to thermosealing container 400 with a foil seal, for example. Further, container 400 has a longitudinal axis A that extends substantially through the center of container 400. In an exemplary embodiment of the invention, neck 404 be located at a distance D₁, measured radially from longitudinal axis A and edge 406 can be located at a distance D₂ measured radially from longitudinal axis A. In such an embodiment, distance D₂ may be less than D₁.

FIG. 4b depicts container 400 after it has been thermosealed. Prior to thermosealing, a distance D₂ may be less than D₁ as described with respect to FIG. 4a. As shown in FIG. 4b, when heat is applied during thermosealing, the plastic softens and upper lip 401 can collapse towards lower lip 402. Substantially at about the same time, edge 406 of container 400 can bend into container 400 and extend down into the container. The resulting container 400, as shown in FIG. 4b includes a flat edge 407 for thermosealing and eliminates the problems caused by having sharp edge because the upper lip bends into the container in such a manner that the edge will not be touched by the mouth of a consumer.

Containers according to embodiments of the present invention may be manufactured using current blow molding equipment and does not require any adjustments to the blower or the demoiler, for example. All that is required is replacement of the neck region mold. For example, containers incorporating the structure of the present invention can be extrusion blow molded from a polyolefin material, for example polyethylene or polypropylene. The material used to form the container can be single layered or multi-layered, as is known in the art. As is known, the containers can incorporate layers of different plastics, or additives in one or more layers, to improve the gas barrier properties of the container. Small lightweight containers can be formed in an end to end fashion, with the necks connected by a moil that is trimmed away in separating the containers. As will be appreciated by persons skilled in the art, materials or methods other than those described herein are encompassed by embodiments of the present invention.

Containers according to embodiments of the present invention can be filled and processed on the same equipment as prior art containers. For example, the lower lip 302 of container 300 can curve outwardly from the neck 304, providing a surface for support during filling operations. Also, top loading performance can be improved without the use of a flange. This is possible because the product can be filled closer to the top of the container which helps aid in support.

Lightweighting of containers according to exemplary embodiments of the invention can be significant. In an exemplary 100 cc container with a height of about 10 cm and a diameter of about 2-4 cm and having a flange, as shown in FIG. 1, for example, the weight of the container may be reduced from about 7 g to about 5 g, a reduction of about 28%. Similarly, in an exemplary 125 cc container with a height of about 5 cm and a diameter of about 6 cm, as shown in FIG. 2, for example, the weight of the container may be reduced from about 6 g to about 4.5 g, a reduction of about 25%. While weight reductions of 25-30% are possible, particularly for small lightweight containers, weight reductions of up to 10% or more, or even 20% or more can be realized with larger containers as well.

The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.

Claims

1. A container comprising:

a neck;

a finish merging with said neck, said finish comprising a first lip connected to said neck; a second lip spaced apart from said first lip in a direction that is substantially perpendicular to said first lip; and a curved portion connecting said first lip with said second lip.

2. The container according to claim 1, further comprising:

a sidewall merging with said neck; and

a base merging with said sidewall.

3. The container according to claim 1, wherein said second lip comprises an edge, and wherein the container has a longitudinal axis, said neck is positioned at a first radial distance from the longitudinal axis, and the edge of said second lip is positioned at a second radial distance from the longitudinal axis.

4. The container according to claim 3, wherein the second radial distance is greater than or equal to the first radial distance.

5. The container according to claim 3, wherein the second radial distance is less than the first radial distance.

6. The container according to claim 1, wherein said second lip collapses towards said first lip while thermosealing a lid to the container.

7. The container according to claim 6, wherein said first and second lips each comprise an inner portion and wherein the inner portion of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip.

8. The container according to claim 6, wherein said first lip comprises an inner portion and said second lip comprises an inner portion and wherein the edge of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip.

9. A sealed container made by the method of:

providing a container according to claim 1; and

thermosealing a lid to said container.

10. The container according to claim 9, wherein said first and second lips each comprise an inner portion and wherein the inner portion of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip during said thermosealing.

11. The container according to claim 9, wherein said first lip comprises an inner portion and said second lip comprises an inner portion and wherein the edge of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip during said thermosealing.

12. A method for sealing a container, comprising:

providing a container having a neck, a finish merging with said neck, said finish comprising a first lip connected to said neck, a second lip spaced apart from said first lip in a direction that is substantially perpendicular to said first lip, and a curved portion connecting said first lip with said second lip; and

thermosealing a lid to the container.

13. The method according to claim 12, wherein said first and second lips each comprise an inner portion and wherein the inner portion of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip during said thermosealing.

14. The container according to claim 12, wherein said first lip comprises an inner portion and said second lip comprises an inner portion and wherein the edge of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip during said thermosealing.

15. A finish for a plastic container, said finish comprising:

a first lip;

a second lip spaced apart from said first lip in a direction that is substantially perpendicular to said first lip; and

a curved portion connecting said first lip with said second lip.

16. The finish according to claim 15, wherein said first and second lips each comprise an inner portion and wherein the inner portion of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip when a heat or pressure is applied to the container.

17. The finish according to claim 15, wherein said first lip comprises an inner portion and said second lip comprises an inner portion and wherein the edge of said second lip touches the inner portion of said first lip when said second lip collapses towards said first lip when heat is applied to the container.

18. A plastic container comprising:

a finish according to claim 15;

a container sidewall merging with said finish; and

a base merging with said sidewall.

19. The finish according to claim 15, wherein said second lip comprises an edge, and wherein the container has a longitudinal axis, said neck is positioned at a first radial distance from the longitudinal axis, and the edge of said second lip is positioned at a second radial distance from the longitudinal axis.

20. The container according to claim 19, wherein the second radial distance is greater than or equal to the first radial distance.

21. The container according to claim 19, wherein said second lip collapses towards said first lip while thermosealing a lid to the container.

22. The container according to claim 19, wherein the second radial distance is less than the first radial distance.

23. The container according to claim 1, wherein said second lip has a thickness of between 0.1 and 1.0 mm.

24. The finish according to claim 15, wherein said second lip has a thickness of between 0.1 and 1.0.