EP1867570B1

EP1867570B1 - Container having a smooth finish

Info

Publication number: EP1867570B1
Application number: EP07011825A
Authority: EP
Inventors: Gilles Perez; David W. Cargile; Bob Stoolmaker
Original assignee: Graham Packaging Co LP
Current assignee: Graham Packaging Co LP
Priority date: 2006-06-15
Filing date: 2007-06-15
Publication date: 2009-11-18
Anticipated expiration: 2027-06-15
Also published as: CA2591368A1; BRPI0702543A; US20060283827A1; ATE449006T1; DE602007003256D1; ES2335311T3; PT1867570E; EP1867570A1; MX2007007281A

Abstract

A container is described which has an upper portion including a finish (508), said finish (508) comprising an upper inwardly projecting lip (501) extending about the longitudinal axis (A) and defining an inner edge (506) having a first inner radial distance (X1) from the longitudinal axis (A); and a lower inwardly projecting lip (502) interconnected with said upper lip (501), said lower lip extending about the longitudinal axis (A) and defining a second inner radial distance (X2) from the longitudinal axis (A), said second inner radial distance (X2) being smaller than said first inner radial distance; wherein said lower lip is spaced apart from said upper lip in a direction substantially parallel to said longitudinal axis. The upper lip includes an outwardly extending circumferential ridge (507) between the inner edge (506) and the lower lip (502), and the lower lip has a portion of decreasing radial distance leading down away from the circumferential ridge leading to a portion of increasing diameter thereby producing an "S" shaped cross-section. When a foil cap is thermosealed onto the container the "S" shaped portion collapses forming a strengthened rim that helps support the cap.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a finish for a plastic container, and more particularly, to a smooth, user-friendly finish for a plastic container.

Related Art

Plastic containers, such as small polyolefin PET containers, may be used for packaging food, dairy, and other drinkable products. Such containers can be sealed at the opening in the neck using a conventional closure such as a screw-on or push-on lid. Additionally or alternatively, these containers can be thermosealed with a suitable lid, for example a foil lid. A thermosealed lid is designed to be pulled off to allow access to the contents of the container. Once opened, the contents can be, for example, drank directly from the container or, in the case of larger containers, spooned, poured, or grasped from the container.
In designing plastic containers, the integrity of the lip of the container may be critical in obtaining a good seal with the closure. This is most commonly accomplished by increasing the thickness of the lip. Additionally, lip thickness may assist in improving the toploading capabilities of the container. Another issue that can arise with container lip design is that the inner edge of the lip (which is usually formed by a trimming operation) can present a sharp edge. This sharp edge can be uncomfortable and/or dangerous to the consumer, whether they are drinking directly from the container, or grasping product located within the container.
An example of a prior art container can be seen in FR 2 240 158 . That container is in accordance with the pre-characterizing part of claim 1 below.
Therefore, there remains a need in the art for a plastic container and / or a container finish that overcomes these and other shortcomings of the prior art.

BRIEF SUMMARY OF THE INVENTION

According to one exemplary embodiment of the arrangement described in WO 2006/069021 a container defines a longitudinal axis, and comprises a neck, a finish merging with said neck, said finish comprising a first lip, a second lip spaced apart from said first lip in a direction that is substantially parallel to the longitudinal axis, and a curved portion connecting the first lip with said second lip.
According to another exemplary embodiment of the arrangement described in WO 2006 / 069021 a method for sealing a container comprises providing a container defining a longitudinal axis and having a neck and a finish merging with said neck, the finish comprising a first lip connected to said neck, a second lip spaced apart from said first lip in a direction substantially parallel to the longitudinal axis, and a curved portion connecting said first lip with said second lip; and thermosealing a lid to the container.
According to yet another exemplary embodiment of the arrangement described in WO 2006/069021 a finish for a plastic container defining a longitudinal axis comprises a first lip, a second lip spaced apart from said first lip in a direction that is substantially parallel to the longitudinal axis, and a curved portion connecting said first lip with said second lip.
According to exemplary embodiment of the present invention, a container defining a longitudinal axis comprises an upper portion including a finish, said finish comprising a first lip extending about the longitudinal axis and defining a first inner radial distance from the longitudinal axis, and a second lip interconnected with said first lip, said second lip, said second lip extending about the longitudinal axis and defining a second inner radial distance from the longitudinal axis, said second inner radial distance being larger than said first inner radial distance. The second lip is spaced apart from said fist lip in a direction substantially parallel to said longitudinal axis.
The invention according to one aspect provides a container defining a longitudinal axis the container comprising an upper portion including a finish, said finish comprising an upper inwardly projecting lip extending about the longitudinal axis and defining an inner edge having a first inner radial distance from the longitudinal axis; and a lower inwardly projecting lip interconnected with said upper lip, said lower lip extending about the longitudinal axis and defining a second inner radial distance from the longitudinal axis, said second inner radial distance being smaller than said first inner radial distance; wherein said lower lip is spaced apart from said upper lip in a direction substantially parallel to said longitudinal axis. When the container is sealed the lower lip forms a smooth surface inwardly with respect to the seal between the lid and the inner edge (506).
Preferably the upper lip includes an outwardly extending circumferential ridge between the inner edge and the lower lip, and the lower lip has a portion of decreasing radial distance leading down away from the circumferential ridge leading to a portion of increasing diameter thereby producing an "S" shaped cross-section. Preferably the upper and lower lips, ridge and other structures of the finish described above are formed as inward and outward meanderings of wall of the finish, which is of a generally uniform thickness. Typically this thickness is in the range 0.1 mm to 0.5 mm.
Another aspect of the invention provides a method of forming a sealed container comprising moulding a container having a sidewall, a base attached to the sidewall at its lower end and an upper portion including; a neck and a finish, wherein the finish comprises: an upper inwardly projecting lip and a lower inwardly projecting lip connecting the neck with the upper inwardly projecting lip; trimming the upper lip to from an axially facing inwardly extending edge, said upper and lower lips together forming a generally "S" shaped structure; wherein the inner diameter of the lower inwardly projecting lip is smaller than the inner diameter of said inwardly extending edge filling the container; and thermosealing a lid onto the axially facing surface of the inwardly extending edge of the upper lip, the pressure of said thermosealing causing an axial collapse of the generally "S" shaped structure, the second lower lip thereby remaining as a smooth surface inwardly with respect to the seal between the lid and the edge. Preferably the whole or a substantial portion of the "S" shaped structure is disposed radially inwardly with respect to a lower margin of the lower lip. Such lower margin would be where it merges into the container neck or a neck flange, if provided. This helps prevent damage to any fastening structures, such as screw threads, on the neck or neck flange when the "S" shaped structure collapses.
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 several embodiments as shown in WO 2006 / 069021 and 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,
FIG. 2 depicts an exemplary embodiment of a prior art container;
FIG. 3 a depicts an exemplary embodiment of a container according to the WO 2006/069021 arrangement before sealing;
FIG. 3b depicts an exemplary embodiment of a container according to the WO 2006/069021 arrangement after sealing.
FIG. 4a depicts an exemplary embodiment of a container according to the WO 2006/069021 arrangement before sealing; and
FIG. 4b depicts an exemplary embodiment of a container according to the WO 2006/069021 arrangement after sealing.
FIG. 5 depicts an exemplary embodiment of a container according to the present invention;
FIG. 6 depicts a side, cross-sectional view of a portion of the container of FIG. 5;
FIG 7 depicts an enlarged portion of the cross-section of FIG 6; and
FIG 8 depicts an exemplary embodiment of the container of FIGS. 5-7 after sealing.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments in accordance with WO 2006/069021 and in accordance with 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 scope of the invention as defined by the appended claims. All references cited herein are incorporated by reference as if each had been individually incorporated.
Exemplary embodiments of the present invention provide a plastic container, such as a polyolefin or PET 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. Additionally or alternatively, exemplary containers according to the present invention can include features for attaching a lid to the container, such as threads or press-on features. Additionally or alternatively, the container finish can include two or more lips of varying inner radii in order to present the consumer with smoothly contoured contact surface when consuming products from the container.
Figure 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.
Figure 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 as described below avoids these and other drawbacks of known lips.
Figure 3a depicts an exemplary embodiment of a thermosealable container 300 as described in WO 2006/069021 . 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 Figure 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 arrangement, 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 a typical example, upper lip and lower lip may be from 0.1 mm to 0.5 mm thick. Ina typical example, the distance S can be about 0.5 to 5.0 mm.
As shown in Figure 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 arrangement as described in WO 2006 / 069021 , neck 304 be located at a distance D₁, measured radially from longitudinal axis A and edge 306 can be located at a distance D₂measured radially from longitudinal axis A. In such an embodiment, distance D₂may be greater than or equal to D₁.
Figure 3b depicts container 300 after it has been thermosealed. As shown inFigure 3b, when heat is applied during thermosealing, the plastic softens and upper lip 301 can collapse towards lower lip 302. 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 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 Figure 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. To create this flat surface 307, for example, heat may be applied during thermosealing reaching 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 Figure 3b, provides other advantages over the prior art containers shown in Figures 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.
Distance D₂ may be less than D₁. In such an arrangement, the upper lip of the container must be sufficiently bendable so as to prevent a sharp edge. Figure 4a depicts a further arrangement of a thermosealable container 400 according to WO 2006 / 069021 . 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 Figure 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 arrangement, 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. Upper lip and lower lip may be from 0.1 mm to 0.5 mm thick. The distance S can be about 0.5 to 5.0 mm.
As shown in Figure 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. Neck 404 may be located at a distance D₁, measured radially from longitudinal axis A and edge 406 can be located at a distance D₂measured radially from longitudinal axis A. In such an embodiment, distance D₂ may be less than D₁.
Figure 4b depicts container 400 after it has been thermosealed. Prior to thermosealing, a distance D₂may be less than D₁ as described with respect to Figure 4a. As shown in Figure 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 Figure 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.
Referring to Figs. 5-8 an exemplary embodiment of a container according to the present invention is shown. The container 500 of Figs. 5-8 can be used with a thermosealed lid, as described above in connection with previous arrangements of WO 2006/069021 or alternatively, can be used with screw-on, press-on, or other known lid types. As shown in Fig. 5, container 500 can include a sidewall 505 having a base 550 attached at its lower end. Container 500 can also include an upper portion including a neck 504 and a finish 508. Container 500 can define a longitudinal axis A.
Referring to Figs. 6 and 7, the upper portion of the container 500 is shown in cross-section. As shown, the finish 508 includes an upper lip 501 and a lower lip 502. The upper lip 501 preferably comprises a generally horizontal surface. It surrounds the longitudinal axis A and extends inwardly from an annular ridge 507, terminating in an inner edge 506. Upper lip 501 and/ or inner edge 506 can be formed, for example, when the container is trimmed, for example, using a trim blade, reamer, or other device, however, other methods for forming these parts are also possible. The lower lip 502 comprises a radially inward projection formed by an inwardly curved wall portion of the finish 508, which extends inwardly on t he opposite side of the annular ridge from the inner edge 506. This curved wall portion can be formed for example during moulding of the container (e.g. blow moulding or injection moulding) however other methods for forming this part are also possible. Beneath the radially inwardly extending projection, the lower lip 502 curves outwardly to a lower margin 510 of the lower lip 502. Preferably it extends at least as far as the annular ridge 507 of the upper lip 501. As shown, the upper lip 501 and the lower lip 502 are interconnected for example by an integral curved portion 509. The upper lip 501 can be spaced apart from the lower lip 502 substantially along the longitudinal axis A. The finish 508 thereby formed has a generally S shaped cross section between the inner edge 506 of the upper lip 501 and the lower outer margin of the lower lip 502. Preferably the finish 508 has a uniform wall thickness throughout.
Referring to Fig. 6, the finish 508 can include an optional neck flange 503, extending from the lower outer margin 510 of the lower lip 502. Alternatively or additionally, the finish 508 can include threads, ridges or other known features for retaining a screw-on, press-on, or other type of closure to the container.
Referring in particular to figure 6, the inner edge 506 of the upper lip 501 defines a first inner radial distance X1 from the longitudinal axis A. The curved wall portion of the lower lip 502 likewise defines a second inner radial distance X2 from the longitudinal axis A. Preferably the second inner radial distance X2 is smaller than the first inner radial distance X1.Thus the relatively smooth, curved surface of the lower lip 502 defines a smaller diameter than the inner edge 506 of the upper lip 501, and can prevent a user from contacting inner edge 506 when dispensing products from container 500 (e.g. drinking a liquid from the container or grasping solid products from the container). This feature can also be beneficial when filling solid products into the container 500 (e.g. pickles), as it can prevent the solid products from being damaged. Thereby, the container 500 can present a user with a relatively smooth, curved surface defined by lower lip 502 when they are consuming products from container 500.
As discussed above, container 500 can be sealed by thermosealing a lid, such as a foil lid (not shown) to the upper lip 501. Further details on this process are provided above with respect to the arrangements of WO 2006/069021 described above. Figures 3-4 apply equally to the embodiment of Figures 5-8. Additionally or alternatively, a screw-on or press-on lid may be provided for use with container 500.
Referring to figure 8, an exemplary embodiment of container 500 is shown after a lid (not shown) is thermosealed onto the finish 508. As discussed above with respect to figures 3-4, the upper lip 501 can collapse down onto the lower lip 502 during thermosealing, to provide a stronger sealing surface for the lid, and/or to improve the top load capacity of the container 500. Additional details regarding the thermosealing are described above in connection with figures 3-4. The "S" shaped cross section formed by the upper and lower lips, collapses down as shown in Fig. 8, because at least a substantial portion of the collapsed structure is inward with respect to the lower outer margin 510 of the lower lip where it joins the neck of neck flange (provided) there is no danger that the neck or neck flange will be damaged during the thermosealing process. Also as the inner edge 506 of the upper lip 501 is at a greater radial distance from the longitudinal axis than the inwardly curved wall of the lower lip 502, the inner edge 506 does not present a sharp uncomfortable edge to a user wishing to drink from the container. The user feels the smooth edge provided by the lower lip, which protrudes from the inside of the container at a greater distance than the sharp upper edge. One of ordinary skill in the art will recognize that the upper lip 501 and lower lip 502 can alternatively maintain the positions shown in figures 5 and 6 during thermosealing and / or any other type of capping process that may be implemented.
Containers according to embodiments of the present invention may be manufactured using current blow moulding 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 mould. For example, containers incorporating the structure of the present invention can be extrusion blow moulded from a polyolefin material, for example polyethylene or polypropylene, PET or other known materials. 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, a neck flange 503 as shown in figure 5 an provide 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 100cc container with a height of about 10 cm and a diameter of about 2-4 cm and having a flange, as shown in Figure 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 125cc container with a height of about 5 cm and a diameter of about 6 cm, as shown in Figure 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.
Finally, summarizing the arrangements described herein and in document WO 2006/069021 , there is provided a first aspect a container defining a longitudinal axis, the container comprising: a neck; a finish merging with said neck, said finish comprising a first lip; a second lip spaced apart from said first lip in a direction that is substantially parallel to the longitudinal axis; and a curved portion connecting said first lip with said second lip. The container according to this aspect may, further comprise: a sidewall merging with said neck; and a base merging with said sidewall. The container according to this aspect, wherein said second lip comprises an edge, and, 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. The second radial distance may be greater than or equal to the first radial distance. Alternatively, the second radial distance is less than the first radial distance.
In this aspect, said second lip may collapse towards said first lip while thermosealing a lid to the container. Said first and second lips each may 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.
Said first lip may comprise 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.
In addition, the arrangement of WO 2006/069021 provides a sealed container made by the method of providing a container according to the first aspect described above, and thermosealing a lid to said container. During said thermosealing in this case said second lip collapses towards said first lip.
According to a second aspect of the arrangement set out in WO 2006 / 069021 there is provided 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 parallel to the longitudinal axis, and a curved portion connecting said first lip with said second lip; and thermosealing a lid to the container. In this method said first and second lips each may comprise an inner portion 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.
Similarly said first lip may comprise an inner portion and said second lip may comprise an inner portion 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.
In a third aspect of the arrangments set out in WO 2006 / 069021 there is provided a finish for a plastic container, defining a longitudinal axis, 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.
In this third aspect said first and second lips may each comprise an inner portion 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. Similarly said first lip may comprise an inner portion and said second lip may comprise an inner portion 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.
In addition the arrangement of WO 2006/069021 provides a plastic container comprising: a finish according to the third aspect of the WO 2006 / 069021 arrangement; a container sidewall merging with said finish; and a base merging with said sidewall. In this case said second lip may comprise an edge, said neck being positioned at a first radial distance from the longitudinal axis, and the edge of said second lip being positioned at a second radial distance from the longitudinal axis. The second radial distance may be greater than or equal to the first radial distance. The second lip may collapse towards said first lip while thermosealing a lid to the container. The second radial distance may be less than the first radial distance. The second lip may have a thickness of between 0.1 and 1.0 mm.
According to an embodiment of the present invention, there is provided a container defining a longitudinal axis, the container comprising: an upper portion including a finish, said finish comprising: a first lip extending about the longitudinal axis and defining a first inner radial distance from the longitudinal axis; and a second lip interconnected with said first lip, said second lip extending about the longitudinal axis, and defining a second inner radial distance from the longitudinal axis, said second inner radial distance being larger than said first inner radial distance; wherein said second lip is spaced apart from said first lip in a direction substantially parallel to said longitudinal axis.
Said second lip may comprise an inner edge that defines said second inner radial distance. Said inner edge may be formed during a container trimming operation. Said first lip may comprise a curved wall portion of said finish, and said curved wall portion defining said first inner radial distance. Said curved wall portion may be formed during moulding of the container. The container may further comprise a sidewall merging with said upper portion; and a base merging with said sidewall. Said second lip may collapse toward said first lip while thermosealing a lid to the container.
In a further aspect the invention provides a container according to the above described embodiment; and thermosealing a lid to said second finish.

Claims

A container defining a longitudinal axis (A), the container comprising:
an upper portion including a finish (508), said finish (508) comprising:
an upper inwardly projecting lip (501) extending about the longitudinal axis (A) and defining an inner edge (506) having a first inner radial distance (XI) from the longitudinal axis (A); and

a lower inwardly projecting lip (502) interconnected with said upper inwardly projecting lip (501), said lower inwardly projecting lip (502) extending about the longitudinal axis (A) and defining a second inner radial distance (X2) from the longitudinal axis (A), said second inner radial distance (X2) being smaller than said first inner radial distance (X1);

wherein said lower inwardly projecting lip (502) lip is spaced apart from said upper inwardly projecting lip (501) in a direction substantially parallel to said an longitudinal axis (A);
characterized in that the structure formed by the upper and lower lips (501,502) is shaped such that the upper lip (501) can collapse down onto the lower lip (502) when the container is thermo sealed by a lid whereby the lower lip (502) forms a smooth surface inwardly with respect to the seal between the lid and the inner edge (506) of the upper lip (501).
The container according to claim 1, wherein said upper inwardly projecting lip (501) includes an outwardly extending circumferential ridge (507) between the inner edge (506) and the lower inwardly projecting lip (502), and the lower inwardly projecting lip (502) has a portion of decreasing radial distance leading down away from the circumferential ridge (507) leading to a portion of increasing diameter thereby producing an "S" shaped cross-section.
The container according to claim 1, wherein said lower inwardly projecting lip (502) comprises a curved wall portion of said finish, said curved wall portion defining said second inner radial distance.
The container of any preceding claim, wherein said upper portion includes a neck (504) connected to said finish (508), said finish (508) having an outwardly extending neck flange (503), where it merges into the neck (504).
The container of any preceding claim, wherein said second inner radial distance (X2) is smaller than the minimum inner radius of said upper portion of the container.
The container of any preceding claim, wherein the material of the upper and lower lips have a thickness in the range 0.1 mm to 1.0 mm, preferably 0.1 mm to 0.5 mm.
The container according to any preceding claim, wherein said upper portion includes a thread or ridge to enable engagement of a screw-on or press-on closure.
A method of forming a sealed container comprising:
molding a container having:
a sidewall (505),

a base (550) attached to the sidewall at its lower end and an upper portion including;

a neck (504) and

a finish (508), wherein the finish (508) comprises:
an upper inwardly projecting lip (501) and a lower inwardly projecting lip (502) connecting the neck (504) with the upper inwardly projecting lip (501);

trimming the upper inwardly projecting lip (501) to form an axially facing inwardly extending edge (506), said upper and lower lips together forming a generally "S" shaped structure;

wherein the inner diameter (X2) of the lower inwardly projecting lip (502) is smaller than the inner diameter (X1) of said inwardly extending edge (506); filling the container; and
thermosealing a lid onto the axially facing surface of the inwardly extending edge (506) of the upper inwardly projecting lip (501),
such that the pressure of said thermosealing causes an axial collapse of the generally "S" shaped structure, the lower inwardly projecting lip (502) thereby remaining as a smooth surface inwardly with respect to the seal between the lid and the edge (506).
A method according to claim 8, wherein the molding step comprises injection molding or blow molding.
A method according to claim 8 or 9, wherein two containers are molded with their upper portions axially joined, and said trimming step comprises separating the two containers.