GB2597341A

GB2597341A - Improvements in or relating to moulded containers

Info

Publication number: GB2597341A
Application number: GB2101696.9A
Authority: GB
Inventors: Bagnall Paul; Lievens Tom
Original assignee: Decapac Packaging Group NV; Innavisions Ltd
Current assignee: Decapac Packaging Group NV; Innavisions Ltd
Priority date: 2020-07-17
Filing date: 2021-02-08
Publication date: 2022-01-26
Anticipated expiration: 2041-02-08
Also published as: GB202011070D0; GB2597341B; GB202101696D0

Abstract

A thermoformed plastic container 10 has a base 12 and an upstanding wall 14 surrounding the base 12. The wall 14 terminates at a flange 16 that extends fully around the periphery of the wall 14 to define a mouth 20 of the container 10. The container 10 is configurable to have a first final flange configuration and a second, different final flange configuration (figure 2). Also disclosed is a method of thermoforming a plastic container having a base, an upstanding wall, and a flange fully extending around the periphery of the wall, including steps of thermoforming a container having an intermediate flange configuration, and converting the intermediate flange configuration to either a first or second final flange configuration.

Description

Improvements in or Relating to Thermoformed Containers The present invention relates to a thermoformed plastic container. Particularly, the present invention relates to a thermoformed plastic food container suitable for liquid or semi-solid foodstuffs such as, for example, soups, sauces, yoghurt and other dairy products. The food container of the present invention may also be used to contain solid foodstuffs such as, for example, nuts, dried fruit pieces and the like.

Thermoformed plastic food containers of the type described above are typically provided with a closure in the form of a lid. In its simplest form, the lid may be flexible and embodied by a piece of plastic film or metal foil that is adhered over an opening of the container. The film or foil is removed from the container to gain access to the foodstuffs within the container. In alternative embodiments, the container may be provided with a more rigid replaceable lid that can be used to re-seal the container after first opening. Such replaceable lids may additional be provided with arrangements that show if the container has been opened or otherwise tampered with.

It is typical that a container requires to be slightly differently configured, especially in the region of the container opening, depending upon the type of closure that is intended to be used.

The present invention seeks to provide a thermoformed plastic food container that is adaptable to receive different closure arrangements.

According to a first aspect the present invention there is provided a thermoformed plastic container having a base and an upstanding wall surrounding the base which terminates at a flange that extends fully around the periphery of the wall to define a mouth of the container, wherein the container is configurable to have a final first flange configuration and alternatively a final second flange configuration, the first and second flange configurations enabling differing closures to be fitted over the mouth of the container.

The final first flange configuration may include a flange portion that can be manipulated so as be at least partially separated from the remainder of the flange.

The flange portion may be fully separable from the reminder of the flange.

The final second flange configuration may include a substantially flat or planar surface that extends fully around the mouth of the container.

The width of the final first flange configuration may be greater than the width of the final second flange configuration.

According to a second aspect of the present invention there is provided a method of thermoforming a plastic container having a base, an upstanding wall that surrounds the base and terminates at a flange that extends fully around the periphery of the wall to define a mouth of the container, the flange having either a first flange configuration or a second, different flange configuration, the method comprising the steps of: providing a mould, the mould corresponding to the shape of a container having the first flange configuration; conforming a thermally softened sheet of plastic to the mould to form a thermoformed plastic container having an intermediate flange configuration; the method having the further step of: after forming the thermoformed plastic container with the intermediate flange configuration, converting the intermediate flange to either a final first flange configuration or a final second flange configuration.

The step of converting the intermediate flange configuration to either the final first flange configuration or the final second flange configuration may comprise the removal of a portion of the intermediate flange. The removal of a portion of the intermediate flange may comprise removal of an outer circumferential portion of the intermediate flange.

Conversion of the intermediate flange configuration to the second final flange configuration comprises removal of a greater amount of the outer circumferential portion of the intermediate flange than required for conversion of the intermediate flange configuration to the first final flange configuration.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a container according to the present invention; Figure 2 shows a perspective view of another container according to the present invention; Figure 3 shows the container of figure 1 fitted with a lid; Figure 4 shows the container of figure 2 fitted with a lid; Figure 5 shows a perspective view of a container similar to that shown in Figure 2 and a part of the mould used to form the container; and Figure 6 shows a perspective view of a container similar to that shown in Figure 1 and a part of the mould used to form the container.

Referring firstly to Figure 1 there is shown a container generally designated 10. The container 10 has a substantially flat circular base 12 and an upstanding wall 14 which extends to and terminates at a flange 16 that extends fully around the periphery of the container 10. The base 12 and wall 14 co-operate to define an interior space 118 of the container 10. The flange 16 further defines a mouth 20 of the container 10. The container 10 shown has an approximate volume of 500m1 and is manufactured from sheet polyethylene terephthalate (PET) by thermoforming. It will be understood that the term "thermoforming" refers to the forming of the container by the thermal softening of a sheet of plastic material which is then conformed to the shape of a mould.

The container 10 is generally frusto-conical in shape which allows empty containers 10 to be nested within one another for storage and transportation. It will be appreciated that the container 10 may have other shapes and volumes.

The flange 16 includes a substantially flat or planar annular upper surface 22 that surrounds the mouth 20 of the container 10. The flange 16 further includes a peripheral edge 24. The annular surface 22 defines an attachment location for flexible lid formed from a plastic film or a metal foil. As noted above, the annular surface 22 is flat. The flange 16 is considered to have a second final flange configuration. The plane of the annular surface 22 is substantially parallel to the plane of the flat base 12 of the container 10. The film or foil may be attached to the annular surface by adhesive or by the application of heat and pressure. The peripheral edge 24 of the flange 16 may be used to retain a rigid replaceable plastic lid 26 (see figure 3) that is configured to fit over the flange 16. The peripheral edge 24 of the flange co-operates with a barb formation provided on the interior of the lid 26 to retain the lid 26 to the container 10.

In use, the container 10 may be provided with both a flexible film or foil lid and a rigid plastic lid 26. The flexible lid may be discarded after the first opening of the container 10 and the rigid lid 26 used to close the mouth 20 of the container 10.

Referring now to figure 2 there is shown a container generally designated 110.

Features common to the container 10 described with reference to figure 1 and prefixed with "1". The container 110 has a substantially circular base 112 and an upstanding wall 114 which terminates at a flange 116 that extends fully around the periphery of the container 10. The base 112 and wall 114 co-operate to define an interior space 118 of the container 110. The flange 116 further defines a mouth of the container 10. The container 110 shown has an approximate volume of 500m1 and is manufactured from sheet polyethylene terephthalate (PET) by thermoforming. The container 110 is generally frusto-conical in shape which allows empty containers 110 to be nested within one another for storage and transportation. It will be appreciated that the container 110 may have other shapes and volumes.

The flange 116 of the container 110 of figure 2 differs from that of the container 10 of figure 1. The flange 116 is considered to have a first final flange configuration that is different from the second final flange configuration described above. More specifically, the flange 116 is wider than the flange 16 of the container 10 described above, and further the upper surface 122 of the flange 116 is not uniformly flat like the upper surface 22 of the flange 16 of the container 10 described with reference to figure 1. The flange 116 is provided with an anti-tamper rib 128 that extends partially around the flat annular upper surface 122. The flange 116 is further provided with a break tab 130 that allows a portion of the flange 116 to be removed or manipulated such that it is partially separated from the remainder of the flange 116. The break tab 130 is further provided with an anti-tamper rib 128a. A weakened region of the flange 116, indicated by broken line 131, enables the break tab 130 to be removed or partially separated from the remainder of the flange 116.

The anti-tamper ribs 128, 128a and break tab 130 of the flange 116 are configured for use with a recessed lid 132 (see figure 4) that fits into and frictionally engages with the mouth 120 of the container 110. When the lid 132 is fitted to the mouth 120 of the container 110, the circumferential edge 134 of the recessed lid 132 lies radially inwardly of the anti-tamper ribs 128,128a and is thus rendered inaccessible. Removal of the lid 132 is effected by the whole or partial separation of the break tab 130 from the flange 116. This exposes and enables access to the portion of the circumferential edge 134 which is aligned with the break tab 130.

As noted above, both of the containers 10,110 are produced by injection moulding.

It has hitherto been necessary to have two differently configured moulds to produce containers 10,110 having the differing flange arrangements 16,116 described above.

According to the present invention, containers 10,110 having the differing flanges 16,116, and thus differing first and second final flange configurations can be formed in a common mould.

Referring now to figure 5 there is shown a container 110 having a flange 116 corresponding to the first final flange configuration as described above with reference to figures 2 and 4. The container 110 shown in figure 5 has a greater depth, and thus a greater volume, than the container 110 of figures 2 and 4 but is otherwise the same. The container 110 is shown above a female mould 136 used to form the container 110 from sheet PET by thermoforming. As will be readily understood by the skilled person, a thermally softened sheet of PET is introduced in to the mould 136, for example by vacuum pressure, in order to conform to the shape of the mould 136 and form the container 110.

The female mould 136 is configured so as to produce the desired characteristics in the thermoformed container 110. In the present instance, this includes the strengthening ribs 128,128a of the flange 116, the break tab 130 and its associated weakened region 131 of the flange 116. Features 140, 142, 144, and 146 of the female mould 136 correspond to the aforementioned features 128, 128a, 130 and 131 of the flange 116.

In use, an intermediate container (not shown) is initially formed by the softened PET sheet and female mould 136. The intermediate container has all of the features of the container 110 described above, however the features of the flange 116 are incorporated within a wider, intermediate flange.

In order to form the final container 110, the intermediate flange is trimmed so as to define a flange 116 having the first final flange configuration. The outer periphery of the intermediate flange is removed so as to leave a flange 116 having the aforementioned anti tamper ribs 128, 128a, break tab 130, flat annular upper surface 122 and peripheral edge 124.

Referring now to figure 6, there is shown a container 10 having a flange 16 corresponding to the second final flange configuration as described above with reference to figures 1 and 3. The container 10 shown in figure 6 has a greater depth, and thus a greater volume, than the container 10 of figures 1 and 3 but is otherwise the same. The container 10 is shown above the same female mould 136 as can be seen in figure 5. The flange 16 of the container 10 however does not include the strengthening ribs 128,128a, break tab 130 and associated weakened flange region 131 of the container 110 of figures 2 and 4 and which would be formed by features 140, 142, 144 and 146 of the female mould portion 136. Instead, the flange 16 includes only the flat annular surface 22.

As before, an intermediate container (not shown) is initially formed by the softened PET sheet and female mould 136. The intermediate container has all of the features of the container 110 described above, however the features of the flange 16 are incorporated within a wider, intermediate flange. A radially outer circumferential portion of the intermediate flange is thereafter removed to provide a flange 16 having the previously described flat annular surface 22. The removed portion of the intermediate flange includes the strengthening ribs 128,128a, the break tab 130 and its associated weakened region 131. It will thus be appreciated that a greater amount of the intermediate flange is removed to form the flange 16 having the second final flange configuration than is required to be removed to form the flange 116 having the first final flange configuration.

The mould tool is configured with a cutter which is selectively operable to remove differing portions of the intermediate flange after moulding of the intermediate container and prior to removal of the final container 10,110 from the mould 136.

The use of the cutter enables a single mould to produce containers 10,110 having different flange configurations.

As noted above, the container 10,110 may be formed from sheet PET. As an alternative, the container 10,110 may be formed from sheet RPET that can contain up to 100% recycled post consumer waste. In yet a further embodiment, the container 10,110 may be formed from laminated PET/RPET having an A/B/A structure with 100% RPET in the central layer and two outer layers of PET. Any thickness combination is possible. For a sheet thickness of 1000micron, the layers may be as follows -with 100 PET! 800 RPET / 100 PET.

Claims

CLAIMS1. A thermoformed plastic container having a base and an upstanding wall surrounding the base, wherein the wall terminates at a flange that extends fully around the periphery of the wall to define a mouth of the container, wherein the container is configurable to have a final first flange configuration and alternatively a final second different flange configuration, the final first and second flange configurations enabling differing closures to be fitted over the mouth of the container.
2. A thermoformed plastic container as claimed in claim 1, wherein the final first flange configuration includes a flange portion that can be manipulated so as be at least partially separated from the remainder of the flange.
3. A thermoformed plastic container as claimed in claim 2, wherein the flange portion is fully separable from the reminder of the flange.
4. A thermoformed plastic container as claimed in any preceding claim, wherein the final second flange configuration includes a substantially flat or planar surface that extends fully around the mouth of the container.
5. A thermoformed plastic container as claimed in any preceding claim, wherein the width of the final first flange configuration is greater than the width of the final second flange configuration.
6. A method of thermoforming a plastic container having a base, an upstanding wall that surrounds the base and terminates at a flange that extends fully around the periphery of the wall to define a mouth of the container, the flange having either a first flange configuration or a second, different flange configuration, the method comprising the steps of: providing a mould, the mould corresponding to the shape of a container having an intermediate flange configuration; conforming a thermally softened sheet of plastic to the mould to form a thermoformed plastic container having the intermediate flange configuration; the method having the further step of: after forming the thermoformed plastic container with the intermediate flange configuration, converting the intermediate flange to either a final first flange configuration or a final second flange configuration.
7. A method as claimed in claim 6, wherein he step of converting the intermediate flange configuration to either the final first flange configuration or the final second flange configuration comprises the removal of a portion of the intermediate flange.
8. A method as claimed in claim 7, wherein the removal of a portion of the intermediate flange comprises removal of an outer circumferential portion of the intermediate flange.
9. A method as claimed in claim 8, wherein conversion of the intermediate flange configuration to the second final flange configuration comprises removal of a greater amount of the outer circumferential portion of the intermediate flange than required for conversion of the intermediate flange configuration to the first final flange configuration.