ES3009507T3 - Process for producing a closure assembly and closure assembly so obtained - Google Patents

Abstract

The present invention relates to a closure assembly for a container, in particular a container filled or refillable with a food product, and more specifically a container filled or refillable with a solid food product. It should be noted that, although preferably designed for closing food containers, the closure assembly of the present invention can also be suitably used for packaging animal feed, cosmetics, pharmaceuticals, chemicals, and agrochemicals. The closure assembly also meets the need to provide an aesthetic closure, while also featuring tamper-evident mechanisms and being easy to use. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Procedure for producing a closure assembly and closure assembly thus obtained

Field of the invention

The present invention relates to a closure assembly for a package, in particular a package filled with or refillable with a food product, and even more particularly a package filled with or refillable with a solid food product. It should be noted that, although preferably designed for closing food packages, the closure assembly of the present invention may also be suitably used for packages of animal feed, cosmetics, pharmaceuticals, chemicals, and agrochemicals.

Background of the technique

As is known, many solid or pourable food products, such as coffee, tea or instant preparations, such as instant milk, soluble barley, instant chocolate, infant formula, flour, sugar and nutritional supplements, such as protein or dietary supplements, or also fruit juice, milk, wine, tomato sauce, etc., are sold in packaged items, such as compound packs, bottles, jars, cans and the like.

Because many of these items are stored, shipped, and ultimately dispensed from the same container, the container must be robust enough to withstand the conditions to which it may be exposed. Furthermore, the container must be easy for the end consumer to use. Formed containers made of plastic and/or metal are often used to store and sell various granular products, particularly in the food and pharmaceutical industries. Some containers may include a lid or closure so that the container can be opened and closed repeatedly. One problem often associated with such containers is leakage of the product from the container. Such leakage typically occurs in the area around the closure. Furthermore, if a lid or closure does not provide an adequate seal, contaminants can more easily enter the product stored in the container, resulting in spoilage or other harmful effects. As such, while some containers include resealable lids that a user can open and close to access the product contained within the container, many of these lids do not provide a sufficiently secure seal.

To overcome such drawbacks, it has been proposed to secure the lid to the ring member by means of a connecting element. While these closure assemblies function satisfactorily, there is a desire in the industry to further improve such closure assemblies. In this regard, means for hermetically sealing a container together with the reclosable lid or overlid are also known. An example of a hermetic seal for a container is the provision of a flexible membrane heat-sealed to the rim of the container, the membrane being removable to provide access to the contents of the container.

For example, US Pat. No. 4,171,084 shows a closure for a container having an outer ring with a central opening closed by a laminated sheet. The ring includes an upper circular portion and a vertically positioned skirt portion. The two portions surround the upper, outer edge of the container rim. The laminated sheet is secured between the bottom surface of the upper portion of the ring and the upper edge of the container rim. The laminate is sealed to both the ring and the container rim by induction heating. Opening the container by removing the ring causes the laminate to separate from the container rim.

US 4,359,169 shows a closure for a container having a membrane sealed between the lower surface of the outer peripheral edge of the closure and the upper surface of the container rim. The closure includes a pivoting inner member surrounded by an outer ring member. The pivoting member includes an edge having a downwardly projecting lip that is sealed to the membrane. As the pivoting member is lifted, the membrane tears adjacent to the lip and a central portion of the membrane is carried by the member.

US 3,892,351 and US 3,973,719 show a package with a membrane heat seal bonded to the upper surface of the package rim. An overlid is provided on a lower surface with a pattern of heat-deformable ribs engaging the membrane rim in the rim area of the package. An RF source is used to heat a conductive portion of the membrane to create a seal with the rim while simultaneously heating the ribs. The heated ribs conform to the membrane surface. GB 2435467A discloses a closure assembly according to the preamble of independent claim 1.

However, all of these closures are quite complex and, consequently, expensive. Furthermore, different elements of the same closure are made of different materials, making the overall closure unsuitable from the perspective of environmental sustainability and disposal.

It is therefore an object of the present invention to provide a closure which overcomes the technical drawbacks of the prior art.

A further object of the invention is to provide a closure that is cheaper than those currently on the market, as well as more environmentally sustainable and easily recyclable.

Summary of the invention

This and other objects are achieved through a closure assembly as defined in the claims, as well as a method for producing the same.

As will be evident from the following detailed description, the closure assembly of the invention allows the contents of the package to be satisfactorily preserved, while providing the consumer with easy opening and easy handling.

Furthermore, the process for producing the closure has resulted in a very fast and efficient sequence of just a few steps, making overall production very convenient from both an economic and environmental perspective.

Brief description of the drawings

The features and advantages of the invention will become clear from the description of a preferred but not exclusive embodiment of the invention, illustrated by working examples provided for illustrative and non-limiting purposes, as well as the attached figures, where:

Figure 1 shows an embodiment of a lid, in a top view (Fig. 1A), in a top perspective view (Fig. 1B), in a side view (Fig. 1C), in a bottom perspective view (Fig. 1D), and in a bottom view (Fig. 1E);

Figure 2 shows an embodiment of a closure assembly, in a top view (Fig. 2A), in a top perspective view (Fig. 2B), in a side view (Fig. 2C), in a bottom perspective view (Fig. 2D), and in a bottom view (Fig. 2E);

Figure 3 shows an embodiment of a hinged closure assembly to a lid, when the lid is in an open position, in a bottom view (Fig. 3A), in a bottom perspective view (Fig. 3B), in a side view (Fig. 3C), in a top perspective view (Fig. 3D), and in a top view (Fig. 3E);

Figure 4 shows an embodiment of a closure assembly hinged to a lid, when the lid is in an open position, in a top perspective view (Fig. 4A), together with an enlarged view of the hook-shaped opening tab (Fig. 4A'); and an embodiment of a closure assembly hinged to a lid, when the lid is in a closed position, in a top perspective view (Fig. 4B), together with an enlarged rear view of the cavity housing the opening tab (Fig. 4B').

Detailed description of the invention

The present invention relates to an improved closure assembly comprising:

- a collar having an outer surface, an inner surface and a flat annular protuberance extending laterally inwardly from said inner surface and defining the area of a central opening, and

- a flexible membrane having a peripheral surface area,

wherein the flat annular protuberance overlaps and embeds the peripheral surface area of the flexible membrane, the latter extending beyond the area of the central opening, thereby closing the same.

Reference will now be made in detail to embodiments of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations may be made to the teachings of the present disclosure without departing from the scope of the appended claims. For example, features illustrated or described as part of one embodiment may be used with another embodiment to produce a further embodiment.

For clarity, not all reference numbers are necessarily present in every figure in the drawing. Furthermore, positional terms such as "top," "bottom," "side," "above," "below," "vertical," "horizontal," etc. refer to the closure assembly when it is in the orientation shown in the drawings. It is clear that the closure assembly may assume different orientations during use.

Referring to Fig. 2, an embodiment of a closure assembly 10 of the present invention is shown, in a top view (Fig. 2A), in a top perspective view (Fig. 2B), in a side view (Fig. 2C), in a bottom perspective view (Fig. 2D), and in a bottom view (Fig. 2E).

The closure assembly 10 is intended for use in closing a package, not shown. The closure assembly 10 includes a collar 12 having a central opening 14. A lid 16, such as that shown in Fig. 1, may releasably engage the collar 12 such that the lid 16 covers the central opening 14. In Fig. 3 and Fig. 4, the lid 16 is pivotally attached to the collar 12 such that the lid 16 may pivot between an open position where a lower surface 18 of the lid 16 is disengaged from the collar 12, and a closed position where the lower surface 18 of the lid 16 engages the collar 12 and the lid 16 covers the central opening 14. The lid 16 is seen in an open position in Fig. 3. In certain embodiments, the lid 16 and collar 12 are pivotally connected via a hinge structure, such as a "flip-top" closure type or via a living hinge 13. In other embodiments, the lid 16 and collar 12 are two separate pieces, as shown in Fig. 1 and Fig. 2, and the lid 16 may be snap-fit onto the collar 12 by the user to engage the collar 12 with the lid 16 and place the lid 16 in a closed position.

In some embodiments, the shape of the collar 12 and the cap 16 is complementary to the shape of the container. For example, when the container is cylindrical, with a generally circular cross-section, the collar 12 and the cap 16 may have a generally circular shape. However, the collar 12 and the cap 16 can be manufactured in a variety of shapes and sizes, including round, elliptical, oval, square, rectangular, hexagonal, etc. In preferred embodiments, the shape of the collar 12 and the cap 16 is complementary to the shape of the container, said shape being elliptical or substantially elliptical, as shown by way of example in the top and bottom views provided in the Figures.

For each of these shapes, the lid 16 may be pivotally attached to the collar 12 (such as by a living hinge 13), or the lid 16 and collar 12 may be two separate pieces, with the lid 16 snap-fitting onto the collar 12 to engage the lid 16 with the collar 12 and place the lid 16 in a closed position. In other embodiments, the shape of the top end of the container may be complementary to the shape of the collar 12 and the lid 16, and the remainder of the container may have a different shape.

The collar 12 is configured to engage and connect to a container. The container typically has an open top end. The closure assembly 10 may be configured such that when the collar 12 is connected to the container, the underside of the closure assembly 10 orients and accommodates the open top end of the container, the central opening 14 being concentric with said open top end. As such, when the lid 16 is engaged with the collar 12 in the closed position, the lid 16 may cover both the central opening 14 in the collar 12 and said open top end on the container.

In preferred embodiments, the lid 16 engages the collar 12 in the closed position simply by exerting pressure on the lid 16.

In some other embodiments, the closure assembly 10 may further include a collar latch member. In embodiments not shown in the Figures, the collar latch member may be located on an exterior surface 27 of the collar 12. In some embodiments, the collar latch member is a latch that may be pivotally attached to the collar 12 via mechanical fasteners commonly known in the art, such as bolts or pins. In some embodiments, the collar latch member is pivotally attached to the collar 12 via a living hinge 13, such that the collar 12 and the collar latch member may be manufactured as an integral piece. In these alternative embodiments, the lid latch member may be located on an exterior surface 28 of the lid 16. The collar latch member is configured to engage the lid latch member to secure the lid 16 to the collar 12 in a closed position. In other embodiments, the lid latch member is a latch that may be pivotally attached to the lid via mechanical fasteners, such as bolts or pins. In some embodiments, the lid latch member is pivotally attached to the lid via a living hinge 13, to secure the lid 16 to the collar 12 in a closed position.

Referring again to Fig. 2, a flexible membrane 30 is partially embedded in the flat annular protuberance 34 of the collar 12. In fact, said flexible membrane 30 can serve both as a protective barrier preventing contaminants from reaching the product during shipment and as a tamper-evident mechanism indicating that a consumer should not purchase or use the product, if the flexible membrane 30 has been tampered with or removed. Thus, advantageously, the closure assembly of the present invention also meets the needs of providing an aesthetically appealing container closure, while having tamper-evident sealing mechanisms and being easy to use.

In particular, said flexible membrane 30 is partially embedded in the flat annular protuberance 34 of the collar 12, and can be opened by a consumer before the first use of the product. "Partially embedded" means that the flat annular protuberance 34 overlaps and embeds the peripheral surface area of the flexible membrane 30, the latter extending beyond the area of the central opening 14, thereby closing the same. Accordingly, with reference to the Figures, the flexible membrane 30 and the central opening 14 coincide, and, as disclosed later with respect to the production method, said peripheral surface area is no longer visible once the closure assembly is formed.

Furthermore, once the flexible membrane 30 is positioned and tightened by the flat annular protuberance 34, the central surface area of the flexible membrane 30 coincides with the central opening 14 in the collar 12, closing the same. With reference to the embodiment of Fig. 2, the flat annular protuberance 34 of the collar 12 overlaps and embeds the peripheral surface area of the flexible membrane 30, to the extent that the latter extends beyond the area of the central opening 14 up to and including points 15. As illustratively shown in the form of a broken line in Fig. 4A', the flexible membrane 30 extends between points 15 and the opening flange 22. Points 15 are preferably point depressions provided on the flat annular protuberance 34 of the collar 12, and which are derived from a preferred embodiment of the production process of the closure assembly 10, as will be detailed later.

The flexible membrane 30 may then be removed by a consumer by cutting or pulling the flexible membrane 30 upwardly through the central opening 14 in the collar 12, thereby giving the consumer access to the contents of the package. Preferably, a release tab may be provided to facilitate removal by the consumer. Such a release tab may be positioned on the flat annular protuberance 34 or on the flexible membrane 30. A preferred embodiment of such a release tab 22 is shown in Fig. 4A and Fig. 4A', which is hook-shaped for easy manipulation by the consumer. In such a preferred embodiment, the release tab 22 is positioned on, and projects upwardly from, the flat annular protuberance 34. This embodiment advantageously reduces the time associated with the closure assembly 10 during manufacturing because the release tab 22 does not have to be connected to the collar 12 through a secondary operation (either manually or by automation). The opening tab 22 projecting from the flat annular protuberance 34 is also advantageously oriented so as to follow the cut lines (dotted lines in Fig. 4a') running between the points 15 and the inner surface 26 of the collar 12. Once the opening tab 22 is pulled upwards and along the cut lines, a strip is torn off around the flexible membrane 30, thus allowing total removal of the latter and access to the contents of the container.

In Fig. 4B and Fig. 4B', a preferred embodiment of the lid 16 is shown, wherein a cavity 17 is present in the lower surface 18 of said lid 16, in order to receive the opening tab 22 of the collar 12, when the closure assembly 10 and the lid 16 are in the closed position. The lid 16 has a lower surface 18 and a lower perimeter 32. The collar 12 includes a flat annular protuberance 34. When the lid 16 is in a closed position and engages the collar 12, the lower perimeter 32 may be in mating contact with the flat annular protuberance 34. Preferably, the collar 12 has a peripheral edge having a diameter larger than the diameter of the collar, thus defining an intermediate lid mating surface. Alternatively, the lid and the collar may be threaded and closed by screwing, if both are round in shape.

In Fig. 2, the flat annular protuberance 34 extends generally laterally inwardly from the inner surface 26 of the collar 12, thereby defining the area of the central opening 14, as well as the exposed area of the flexible membrane 30. It will be readily apparent that, when the cap 16 is in the closed position, the flat annular protuberance 34 of the collar 12 faces the lower perimeter 32 of the cap 16, and the lower surface 18 faces the flexible membrane 30.

Preferably, the flexible membrane 30, the collar 12 and the cap 16 are made of the same or different thermoplastic materials.

In preferred embodiments, the flexible membrane 30, the collar 12 and the cap 16 are made of the same thermoplastic material, in order to improve the recyclability of the entire closure assembly, as well as to reduce overall production costs.

More preferably, said thermoplastic material is selected from acrylic (PMMA), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), thermoplastic elastomer (TPE) and mixtures thereof.

Preferably, said thermoplastic material is polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET).

Preferably, the thickness of the flat annular protuberance 34 is 5 to 30 times the thickness of the flexible membrane 30, preferably 10 to 20 times. These ratios allow the peripheral surface area of the flexible membrane 30 to be excellently embedded in the flat annular protuberance 34, thereby improving the tamper-evident sealing properties of the closure assembly 10.

In preferred embodiments, the thickness of the flexible membrane 30 is 20-150 pm, more preferably 40-100 pm, even more preferably 50-80 pm.

In preferred embodiments, the thickness of the flat annular protuberance 34 is 0.5-2.0 mm, preferably about 1.0 mm.

In another aspect, the present invention relates to a method for producing the closure assembly described above.

In particular, the procedure for producing the closure assembly comprises the following steps:

(i) providing an injection molding apparatus equipped with a mold having an integrated vacuum system, a manipulator, and a flexible membrane storage,

ii) with the mold open, have the manipulator take the flexible membrane from storage and position it inside the mold, where the vacuum system is active, so that the flexible membrane maintains the given position also once the manipulator releases it,

iii) close the mold and start the injection of the thermoplastic material,

iv) Once the injection is complete, cool and release the molded closure assembly. The mold may be a single-cavity mold or a multi-cavity mold, where a single-cavity mold produces a single closure assembly per cycle, while a multi-cavity mold produces more than one closure assembly per cycle.

In preferred embodiments, the mold is a multi-cavity mold having 4 and 16 cavities, more preferably 6 and 10 cavities. The number of cavities depends on the size of the closure assembly to be produced: the larger the size, the lower the number of cavities, unless the size of the overall mold and injection molding apparatus is increased.

It is understood that, when the mold is a multi-cavity mold, the manipulator positions a number of flexible membranes corresponding to the number of cavities.

In preferred embodiments, the mold is provided with punctual protuberances corresponding to the peripheral surface area of the flexible membrane, ensuring correct positioning and tightening of said flexible membrane in step iii), when the mold is closed and the thermoplastic material is injected. Indeed, said punctual protuberances, once the mold is closed, fix the peripheral area of the flexible membrane in the position given by the manipulator until the thermoplastic material embeds it. The presence of said punctual protuberances on the mold results in visible punctual depressions, i.e., points 15, on the flat annular protuberance 34 of the finished collar 12, as shown in Figs. 2-4.

Preferably, during the picking and positioning step ii), the flexible membranes are charged with static electricity so that, once placed inside the mould cavities, they adhere perfectly to the latter, in addition to the tightening effect given by the vacuum system: this makes it possible to minimise the risks of movement of the flexible membrane during the injection of the thermoplastic material into the mould.

Once the flexible membrane is placed in the mold, the injection cycle begins, the mold closes, and the cavities are filled with molten thermoplastic material, thus embedding the peripheral area of the flexible membrane.

At the end of the injection cycle, the cooling cycle begins. The material inside the mold cools, the mold opens, and the closure assembly thus obtained is released. Advantageously, the single injection-molded closure assembly, which has a flexible membrane molded inside, can be made of a single thermoplastic material or of at least two types of mixed thermoplastic material or thermoplastic material molded together.

In a further embodiment, the closure assembly is hinged to a lid, such that the mold is designed to produce a single injection molded closure assembly having a flexible membrane molded therein and hinged to a lid.

It should be noted that the process of the present invention allows the closure assembly to be injection molded while partially embedding a flexible membrane, to give a single piece ready for use and easily disposable and recyclable.

Furthermore, this process advantageously allows for maintaining or achieving very high print quality and reproducing high-resolution graphic effects and specific images on the flexible membranes before they are placed in the mold. Therefore, words and/or graphic elements (such as opening instructions) can also be printed on the flexible membranes, thus further utilizing the surface of the flexible membrane to communicate additional information or for aesthetic purposes.

In this way, the closure assembly can be removed from the mold and no longer requires further processing before being attached to the container.

Preferably, the mold temperature during injection is 180-250 °C.

The injection in step iii) can be carried out at high pressure and at 220°C for PP and 180°C for PE to allow the thermoplastic material to flow into the mould.

The closure assembly, as such or hinged to a cap, as previously disclosed, leads to significant energy savings, as it utilizes a single step, rather than at least two separate steps required to produce the collar and then heat-seal the membrane. Therefore, it is economically advantageous in addition to increasing production speed.

The closure assembly can also be produced at low cost using standard machinery and procedures, ensuring the tightness and recyclability of the entire closure, thus overcoming the drawbacks of the US documents mentioned above.

Furthermore, using the bi-injection system, it is possible to make the closure assembly (with or without a hinged lid) in two or more colors, or even in two or more different plastics, even if it is in a single piece.

The closure assembly, at least in the configuration shown in the Figures, provides significant advantages also in logistical terms both in the handling and storage steps, being easily stackable.

In a further aspect, the present invention relates to a closure assembly obtainable by the production process described above. In particular, the present invention also relates to a closure assembly (10) comprising:

- a collar (12) having an outer surface (27), an inner surface (26) and a flat annular protuberance (34) extending laterally inwardly from said inner surface (26) and defining the area of a central opening (14), and

- a flexible membrane (30) having a peripheral surface area,

wherein the flat annular protuberance (34) overlaps and embeds the peripheral surface area of the flexible membrane (30), the latter extending beyond the area of the central opening (14), thus closing the same,

and obtainable through the unique molding process comprising:

(i) providing an injection molding apparatus equipped with a mold having an integrated vacuum system, a manipulator, and a flexible membrane storage,

ii) with the mould open, have the manipulator take the flexible membrane from storage and place it inside the mould, where the vacuum system is active, so that the flexible membrane maintains the given position also once the manipulator releases it,

iii) close the mold and start the injection of the thermoplastic material,

iv) once the injection is complete, cooling and releasing the thus molded closure assembly. It should be noted that, although preferably designed for closing food packages, the closure assembly of the present invention can also be suitably used for packages of animal feed, cosmetics, pharmaceuticals, chemicals, and agrochemicals, that is, anytime a product needs to be better sealed and stored for long periods of time. Thus, in a further aspect, the present invention also relates to a package sealed by the closure assembly 10 as described above, said package being a package for storing food, animal feed, cosmetics, pharmaceuticals, chemicals, or agrochemicals.

Furthermore, advantageously, the closure assembly of the present invention also meets the needs of providing an aesthetically appealing container closure, while having tamper-evident sealing mechanisms and being easy to use.

It should be understood that all aspects identified as preferred and advantageous for the closure assembly are to be considered equally preferred and advantageous for the production process, and vice versa, as well as for the container sealed thereby. Furthermore, all possible combinations of the preferred aspects of the closure assembly, the production processes thereof as indicated above, as well as the container sealed thereby, are further considered disclosed and, therefore, equally preferred.

Claims (14)

1. A closure assembly (10) comprising: - a collar (12) having an outer surface (27), an inner surface (26) and a flat annular protuberance (34) extending laterally inwardly from said inner surface (26) and defining the area of a central opening (14), and - a flexible membrane (30) having a peripheral surface area, wherein the flat annular protuberance (34) overlaps the peripheral surface area of the flexible membrane (30), the latter extending beyond the area of the central opening (14), thus closing the same, characterized in that the flat annular protuberance (34) embeds said peripheral surface area of the flexible membrane (30). 2. The closure assembly (10) of claim 1, wherein an opening tab (22) projects upwardly from the planar annular protuberance (34), and is oriented so as to follow the cut lines running along the inner surface (26) of the collar (12), so as to allow complete removal of the flexible membrane (30). 3. The closure assembly (10) of claim 1 or 2, wherein a lid (16) is pivotally attached to the collar (12), preferably through a living hinge (13). 4. The closure assembly (10) of any one of claims 1-3, which is made of thermoplastic material selected from acrylic (PMMA), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), thermoplastic elastomer (TPE) and mixtures thereof. 5. The closure assembly (10) of claim 4, which is made of thermoplastic material selected from polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). 6. The closure assembly (10) of any one of claims 1-5, wherein the collar (12) and the flexible membrane (30) are made of the same thermoplastic material. 7. The closure assembly (10) of any one of claims 1-5, wherein the thickness of the flat annular protuberance (34) is 5 to 30 times the thickness of the flexible membrane (30), preferably 10 to 20 times. 8. The closure assembly (10) of any one of claims 1-7, wherein the thickness of the flexible membrane (30) is 20-150 pm, preferably 40-100 pm, more preferably 50-80 pm. 9. The closure assembly (10) of any of claims 1-8, wherein the thickness of the flat annular protuberance (34) is 0.5 to 2.0 mm, preferably about 1.0 mm. 10. A method for producing the closure assembly (10) of any one of claims 1-8, the method comprising the following steps: (i) providing an injection molding apparatus equipped with a mold having an integrated vacuum system, a manipulator, and a flexible membrane storage, ii) with the mold open, have the manipulator take the flexible membrane from storage and place it inside the mold, where the vacuum system is active, so that the flexible membrane maintains the given position also once the manipulator releases it, iii) close the mold and start the injection of the thermoplastic material, iv) once the injection is completed, cool and release the closure assembly thus molded. 11. The method of claim 10, wherein the mold is a multi-cavity mold having 4-16 cavities, preferably 6-10 cavities. 12. The method of claim 10 or 11, wherein the mold is provided with point protuberances in correspondence with the peripheral surface area of the flexible membrane, ensuring the correct positioning and tightening of said flexible membrane in step iii), when the mold is closed and the thermoplastic material is injected. 13. The method of any one of claims 10-12, wherein during the collection and positioning step ii), the flexible membrane is charged with static electricity so that, once placed inside the mold, it adheres perfectly to the latter. 14. A container sealed by the closure assembly (10) of any one of claims 1-9, said container being a container for storing food, animal feed, cosmetic, pharmaceutical, chemical or agrochemical products.