CONTAINER WITH SEAMLESS FINISH
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 finish for a plastic container for accepting a heat-sealed lid.
Related Technology Heat-sealed containers, such as small polyolefin containers, can be used to package foods, dairy products, and other drinkable products. These containers can be heat-sealed in the opening in the neck with a suitable lid, for example, a thin sheet metal lid. The lid is designed to be detached to allow access to the contents of the container. The content can be, for example, drunk directly from the container or, in the case of larger containers, emptying the container. In the design of these containers, the integrity of the lip of the container can be critical to obtain a good seal. This is very commonly achieved by increasing the thickness of the lip. Additionally, the thickness of the lip can help
improve the upper load capacity of the container. However, the lip of the container should not be so thick to add unnecessary weight to the container. An additional problem that may arise when the thickness of the lip is reduced, is that the lip of the container can be submerged in the container during the heat sealing, avoiding a hermetic seal and resulting in leakage of product from the container.
SUMMARY OF THE INVENTION Exemplary embodiments of the invention provide a container having a neck and a finish that fuses with the neck. The finish includes a first lip connected to the neck, a second lip separated from the first lip in a direction that is substantially perpendicular to the first lip, and a curved portion connecting the first lip to the second lip. Additional exemplary embodiments of the invention provide a method for sealing a container including providing a container having a neck, a finish that fuses with the neck, where the finish includes a first lip connected to the neck, a second lip separated 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 heat sealing 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 separated from the first lip in a direction that is substantially perpendicular to the first lip, and a curved portion connecting the first lip to the second lip. The additional objects and advantages, as well as the structure and function of the preferred embodiments will become apparent upon consideration of the description, drawings and examples.
BRIEF DESCRIPTION OF THE FIGURES 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, where like reference numbers generally indicate identical elements. , functionally similar and / or structurally similar. FIGURE 1 describes an exemplary embodiment of a prior art container according to the present invention; FIGURE 2 describes an exemplary mode of
a container of the prior art according to the present invention; FIGURE 3a describes an exemplary embodiment of a container according to the present invention prior to sealing; FIGURE 3b describes an exemplary embodiment of a container according to the present invention after sealing; FIGURE 4a describes an exemplary embodiment of a container according to the present invention prior to sealing; and FIGURE 4b describes an exemplary embodiment of a container according to the present invention after sealing.
DETAILED DESCRIPTION OF THE INVENTION The embodiments of the invention are described in detail later. In describing the modalities, specific terminology was used in order to be clear. However, it is not intended that the invention be limited to the specific terminology thus selected. Although specific exemplary modalities are discussed, it should be understood that this was done solely for purposes of illustration. An expert in the relevant art will recognize that they can be used
other components and configurations without departing from the spirit and scope of the invention. All the references cited here are incorporated as a reference, as if each one had been incorporated individually. Exemplary embodiments of the present invention provide a heat-sealable polyolefin container. Exemplary containers according to the present invention can include a very thin lip which is adapted for heat sealing at high sealing temperatures, without undesirable deformation. In an exemplary embodiment of the invention, two neck lips of a container can be adhered together to provide a strong resistance to deformation of the lip. FIGURE 1 discloses one embodiment of a prior art container 100 having a sealing lip 101 for receiving a heat sealed lid (not shown). The container 100 has a neck 102 that includes a neck flange 103 that fuses with the sealing lip 101. When the container 100 is heat sealed, the sealing lip 101 must be thick enough, so that the sealing temperature does not soften the plastic and have the sealing lip 101 submerged in the container before sealing the thin sheet of metal. When softening occurs, the upper surface of the sealing lip 101 can be bent and the
edge 104 may curl into the interior of the container. As a result, the upper surface, where the seal will be formed, is curved, and thus has less surface area for the junction of the seal of the thin sheet of metal. As a result, the seal may fail, resulting in a rejected container. To prevent the sealing lip 101 from being immersed in the container 100, the lip is typically 0.5 to 1.0 mm thick, for example. That thickness, however, results in an increase in the amount of plastic used to produce the container, which in turn, makes the container heavier and more expensive to build. The flange 103 serves several purposes in that container. First, it provides a point of contact to support a filling line. Second, the flange provides superior load resistance for storing and stacking containers. However, the flange adds weight to the container that is not necessarily required for the structural support of the container itself. Another disadvantage of flange 103 is that it creates a concave inner surface in which the contained product may become trapped during storage or use, or it may be difficult to remove when it is discharged from the container. Figure 2 describes a modality of a
prior art container 200 having a sealing lip 201 and a neck 202 that fuses with the sealing lip 201. Although the container 200 avoids the weight of an aggregate flange, the design of the lip 201 and the edge 204 suffers from the same disadvantages as the container 100 with the lid 101 and the edge 104. As similarly discussed above with respect to the container 100, when the container 200 is heat sealed, the sealing lip 201 must be thick enough, so that the The sealing temperature does not soften the plastic and cause the sealing lip 201 to be immersed in the container prior to sealing. To prevent the sealing lip 121 from being immersed in the container 200, the lip should be, for example, 0.5 to 1.0 mm thick. That thickness, however, results in an increase in the amount of plastic used to produce the container, which in turn, makes the container heavier and more expensive to build. The sealing lips 101, 201 in these prior art containers suffer from several disadvantages. For example, the edge 104, 204 may be relatively sharp, causing discomfort when a consumer drinks from the container. Edge edge 104, 204 may also be increased during the heat sealing process when lip 101, 201 softens during
the seal. Additionally, as mentioned above, the edge 104, 204 of the lip 101, 201, may curl downward during heat sealing, resulting in an incompetent seal and a leaking container. Although making the lip thicker results in a more competent and less curly seal, it typically does not prevent the edge 104, 204 from being sharpened and adds initial weight to the container. The finish having a lip according to the present invention avoids these and other known lip disadvantages. Figure 3a describes an exemplary embodiment of a heat sealable container 300 according to one embodiment of the present invention. The container 300 may have a finish 308 that includes an upper lip 301, a lower lip 302, a curved portion 303, a neck 304. The container 300 also includes a side wall 305. As shown in Figure 3a, the neck 304 merges with side wall 305; the lower lip 302 fuses with the neck 304; the curved portion 303 fuses with the lower lip 302; and the upper lip 301 fuses with the curved portion 302. In that embodiment, the upper lip 301 and the lower lip 302 are substantially horizontal, so that the upper lip is spaced a distance S from the lower lip in a direction that is substantially
perpendicular to that of the lower lip. In an exemplary embodiment of the invention, the upper lip and the lower lip may be 0.1 mm to 0.5 mm thick. In an exemplary embodiment of the invention, the distance S can be from about 0.5 to 5.0 mm. As shown in Figure 3a, the upper lip 301 has an edge 306 that can be a sharp edge before heat sealing the container 300 with a thin sheet metal seal, for example. Further, the container 300 has a longitudinal axis A that extends substantially through the center of the container 300. In an exemplary embodiment of the invention, the neck 304 is located at a distance Di, measured radially from the longitudinal axis A and the edge 306 may be located at a distance D2 measured radially from the longitudinal axis A. In that embodiment, the distance D2 may be greater than or equal to Di. Figure 3b describes the container 300 after it has been heat sealed. As shown in Figure 3b, when heat is applied during heat sealing, the plastic softens and the upper lip 301 may collapse towards the lower lip 302. In an exemplary embodiment of the invention, the edge 306 may come into contact with the lower lip 302, effectively removing edge edge 306 and creating an edge
"soft" from the curve connecting the neck 304 to the lower lip 302. Because the upper lip 301 and the lower lip 302 are both substantially horizontal, when heat is applied during sealing, the degree to which the upper lip submerged in the container is limited by the lower lip 302. Instead of being excessively bent, the upper lip 301 may come into contact with the lower lip 302, and due to the softening occurring during sealing, the upper lip 301 and the lip bottom 302 can adhere to each other to give a strong resistance to the lip. That container can also provide a thin, lightweight lip that remains resistant to the top load. As shown in Figure 3b, after heat sealing, the resulting sealed lip 301, 302 may have a substantially flat surface for sealing. Contrary to the prior art lips, which after heat sealing can have a curved surface, the container 300 provides a flat surface 307 for heat sealing that provides more surface area to seal the thin sheet of metal to the upper lip 301. In one exemplary embodiment of the invention, to create this flat surface 307, for example, heat may be applied during the heat sealing
that reaches the finished container 300, the softening of the upper lip 301 and the curved portion 303. When the upper lip 301 is heated during sealing, the space S can act as an insulator between the upper lip 301 and the lower lip 302, so that the lower lip 302 do not over-soften, maintaining the integrity and structure of the lower lip and maintaining a substantially flat surface to accept the seal. When this occurs, the upper lip 301 and the curve 303 may collapse towards the lower lip 302 and cause the upper lip 301 to adhere to the lower lip 302. The resulting container 300, as shown in Figure 3b, provides other advantages on the prior art containers shown in Figures 1 and 2. For example, in the container 300, no product remains trapped because the container 300 does not have a flange on the neck or some other sandwich area that traps the product. Additionally, the sharp edge is removed because the edge 306 fuses in the lower lip 302, while at the same time, a flat surface 307 is maintained for the heat seal. In a further exemplary embodiment of the invention, the distance D2 may be less than Di. In that modality,
the upper lip of the container must be sufficiently flexible to avoid a sharp edge. Figure 4a describes an exemplary embodiment of a heat sealable container 400 according to one embodiment of the present invention. The container 400 may have a finish 408 that includes an upper lip 401, a lower lip 402, a curved portion 403, a neck 404. The container 400 also includes a side wall 405. As shown in Figure 4a, the neck 404 merges with side wall 405; the lower lip 402 merges with the neck 404; the curved portion 403 fuses with the lower lip 402; and the upper lip 401 is fused with the curved portion 402. In that embodiment, the upper lip 401 and the lower lip 402 are substantially horizontal so that the upper lip is spaced 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, the upper lip and the lower lip may be 0.1 mm to 0.5 mm thick. In an exemplary embodiment of the invention, the distance S can be from about 0.5 to 5.0 mm. As shown in Figure 4a, the upper lip 401 has an edge 406 which can be a sharp edge before heat sealing the container 400 with a
Thin sheet metal seal, for example. In addition, the container 400 has a longitudinal axis A that extends substantially through the center of the container 400. In an exemplary embodiment of the invention, the neck 402 is located at a distance Di, measured radially from the longitudinal axis A and the edge 406 may be located at a distance D2 measured radially from the longitudinal axis A. In that embodiment, the distance D2 may be less than Di. Figure 4b describes container 400 after it has been heat sealed. Prior to heat sealing, a distance D2 may be less than Di as described with respect to Figure 4a. As shown in Figure 4b, when heat is applied during heat sealing, the plastic softens and the upper lip 401 can collapse towards the lower lip 402. Substantially about the same time, the edge 406 of the container 400 can be bent towards the container 400 and extend down to the container. The resulting container 400, as shown in Figure 4b, includes a flat edge 407 for heat sealing and eliminates the problem caused by having a sharp edge because the upper lip is bent towards the container such that the edge will not be touched through the mouth of the consumer.
The containers according to the embodiments of the invention can be manufactured using the current blow molding equipment and do not require any adjustment to the bellows or demolition, for example. All that is required is the replacement of the mold of the neck region. For example, containers incorporating the structure of the present invention can be blow molded by extrusion of a polyolefin material, for example, polyethylene or polypropylene. The material used to form the container can be single layer or multiple layers, as is known in the art. As is known, 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 manner, with the neck connected by a joint that is cut to separate the containers. As will be appreciated by those skilled in the art, materials or methods other than those described herein are encompassed by the embodiments of the present invention. The containers according to embodiments of the present invention can be filled and processed in the same equipment as the containers of the prior art. For example, lower lip 302 of container 300
can curl out from the neck 304, providing a support surface during filling operations. Also, performance in the top load 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 support. Lightening the weight of the containers according to the exemplary embodiments of the invention can be significant. In an exemplary lOOcc container with a height of approximately 10 cm and a diameter of approximately 2-4 cm and having a rim, as shown in Figure 1, for example, the weight of the container can be reduced by approximately 7 g to about 5 g, a reduction of about 28%. Similarly, in an exemplary container of 125 cc 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 can be reduced from about 6 g to about 4.5 g, with a reduction of approximately 25%. Although 25-30% weight reductions are possible, particularly for lightweight, small containers, weight reductions of up to 10% or more, or even 20% or more, can be obtained 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 mode known to the inventors for making and using the invention. Nothing in this specification shall be considered as limiting the scope of the present invention. All the examples presented are representative and not limiting. The embodiments of the invention described above may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the foregoing teachings. Therefore, it should be understood that within the scope of the claims and their equivalents, the invention may be practiced otherwise than specifically described herein.