MX2015002002A

MX2015002002A - A cap for containers.

Info

Publication number: MX2015002002A
Application number: MX2015002002A
Authority: MX
Inventors: Alessandro Falzoni
Original assignee: Sacmi
Priority date: 2012-10-18
Filing date: 2013-10-02
Publication date: 2015-06-02
Also published as: WO2014060893A1; IN2015KN00239A; BR112015003177B1; ITMO20120253A1; BR112015003177A2

Abstract

A cap for a container comprises: - a side wall (2) provided with at least one anchoring element (3) for removably fixing the cap (1; 101) to a neck (20) of the container; - a top wall (4) arranged transversely to the side wall (2); - a connection zone (5) in which the side wall (2) is connected to the top wall (4). The connection zone (5) comprises a first wall portion (6) which projects from the side wall (2) towards the inside of the cap (1; 101) and a second wall portion (7) which joins the first wall portion (6) to the top wall (4), the first wall portion (6) and the second wall portion (7) defining a recess structure (9) on an outer surface of the connection zone (5).

Description

A CONTAINER COVER DESCRIPTIVE MEMORY The description relates to a lid for containers, in particular, with a lid that can be obtained by molding a polymeric material. The lid according to the invention is particularly suitable for closing bottles, for example, intended to contain liquids, although theoretically it can be used to close other types of containers, for example jars.

The covers for bottles are known, said covers comprise a cylindrical side wall, on an inner surface from which one or more anchoring elements are obtained, for example, threads. The anchoring elements are convenient to allow the lid to be removably attached to the neck of a bottle. In addition, the known covers comprise an upper wall having a substantially circular flat shape, from which the cylindrical side wall projects.

An inner sealing lip and an outer sealing lip project from the upper wall of the known covers towards the inside of the lid. The inner sealing lip and the outer sealing lip have an annular shape, but the inner sealing lip has a smaller diameter than the outer sealing lip. It is intended that the inner sealing lip engage an inner side surface of the bottle neck, while the outer sealing lip is intended to engage an outer side surface of the bottle neck. In this way, the inner sealing lip and the outer sealing lip make it difficult, if not impossible, for the substances to pass from the inside of the bottle to the outside or vice versa.

The caps provided with two sealing lips of the aforementioned type are described in, for example, US 4489845, EP0076778 and US 4560077.

The caps provided with an inner sealing lip and an outer sealing lip of the type described above have a number of disadvantages that arise when the bottle neck in which the cap is placed is subjected to temperatures above the ambient temperature. For example, bottlenecks that are filled by means of hot filling processes can easily reach temperatures of about 70 to 90 ° C during filling and capping steps and at moments immediately after them. In addition, during transport from the place of manufacture to the point of sale it can happen that temperatures of approximately 40 to 50 ° C are reached in the vehicles that transport the sealed and stuffed bottles, especially during the summer.

At these temperatures, the bottleneck tends to widen as a result of both the thermal expansion and the pressure that builds up inside the bottle, especially if the bottle contains a carbonated drink. The lid, which is usually made of materials that have a higher percentage of crystalline phase and that therefore are more rigid compared to the bottleneck, expands less than the latter. Therefore, the neck of the bottle applies on the lid, and in particular on the outer sealing lip, a force tending to extend the sealing lip circumferentially.

Due to its limited thickness, the outer sealing lip is sometimes unable to withstand the extension force applied by the neck of the bottle. In this way, it can happen that the outer sealing lip is significantly deformed, so that the sealing capacity thereof is compromised.

There are also known covers comprising a flange projecting into the interior of the cover from a connection zone between the cylindrical side wall and the top wall. For example, covers of this type are described in EP 0960054 and in EP 0316167. The flange increases the rigidity of the connection zone connecting the cylindrical side wall and the top wall and ensures a good resistance to the extension action exerted by the neck of the bottle when the latter expands.

However, the flange of the caps described above has the advantage that, in the connection zone between the cylindrical side wall and the upper wall of the lid, the thickness of the lid is relatively large. This implies a significant increase in the amount of polymeric material necessary to manufacture a single lid. Furthermore, due to its great thickness, it is possible that the connection zone between the cylindrical side wall and the upper wall can not be cooled easily and uniformly during the molding of the lid. In addition, the flange can cause the connection zone between the cylindrical side wall and the top wall to become excessively rigid, which can result in difficulty in applying the cap on the bottle, when the bottle has to be sealed after the passage of filled in.

An object of the invention is to improve the lids for closing containers, particularly bottles.

A further objective is to provide a lid for containers that is capable of effectively containing any expansion or enlargement of a container neck on which the lid is placed.

Another objective is to provide a lid for containers that does not require an excessive amount of polymeric material to be produced.

Still another objective is to provide a lid for containers that can be easily cooled during the production of a lid.

An additional objective is to provide a lid for containers that can be easily applied to filled containers that must be sealed.

In accordance with the invention, a lid is provided for a container comprising: a side wall provided with at least one anchoring element for removably attaching the lid to a container neck; an upper wall disposed transverse to the side wall; a connection zone in which the side wall is connected to the upper wall; wherein the connection zone comprises a first wall portion projecting from the side wall into the interior of the lid and a second wall portion joining the first wall portion to the upper wall, so that the second portion of the wall The wall can be coupled as a seal with an outer side surface of the container neck, the first wall portion and the second portion wall defining a hollow structure on an outer surface of the connection zone.

In the cover according to the invention, the second wall portion of the connection area comes into contact with the outer side surface of the neck of the container, exerting the function that in covers according to the vanguard technology was exerted by the lip of exterior sealing. The second wall portion of the connection zone has a greater stiffness than the outer sealing lip of the known covers, which was projected as a cantilevered beam from the top wall of the lid and was therefore very flexible. On the contrary, in order to deform the second wall portion of the lid according to the invention, it is necessary to compress the first wall portion along a direction in which the first wall portion extends, which requires relatively A big effort. Consequently, due to the conformation of the connection zone, the lid according to the invention is capable of effectively opposing any expansion or swelling of the neck of the container.

In addition, the egg structure makes the connection area on the outside of the lid lighter. This makes it possible to reduce the amount of material required to form a single lid, in comparison with known covers provided with a flange in the connection zone.

In addition, the hollow structure allows the cooling of the lid to be simple, in case the lid is obtained by molding a polymeric material. In fact, the gap structure prevents excessive amounts of polymeric material from being concentrated in the connection zone. These excessive amounts may require longer cooling times compared to other areas of the lid.

Finally, the hollow structure maintains the rigidity of the connection zone below a threshold higher than that the lid could be applied with difficulty to the full container to be sealed. At the end of the industrial filling process, the container can be filled with ease.

In one embodiment, the gap structure comprises a plurality of holes distributed circumferentially on the outside of the lid around the connection area.

In addition, the cap may comprise a plurality of reinforcement ribs circumferentially distributed on the outside of the cap along the connection zone.

A reinforcing rib separates each gap from the adjacent gap.

The reinforcing ribs serve to further increase the stiffness of the connection zone, so that the cap is able to resist the expansion or swelling of the neck, without, however, reaching levels of rigidity so that difficulties are created when the container must be covered industrially.

In one embodiment, an inner sealing lip having, for example, an annular conformation, projects from the upper wall inside the lid, so that it engages as a seal with an inner surface of the neck of the container.

When the lid is applied in a container, the inner sealing lip ensures a good seal in contact with the inner side surface of the neck of the container. The second wall portion of the connection zone ensures a good seal in contact with the outer side surface of the neck of the container. In this way it is possible to prevent substances from passing between the interior of the container and the external environment, or vice versa.

The invention can be better understood and implemented with reference to the accompanying drawings which illustrate some exemplary modalities, which do not limit the implementation thereof, in which: Figure 1 is a bottom view of a lid for closing a container; Figure 2 is a cross-sectional view taken along the plane II-II of Figure 1; Figure 3 is a cross-sectional view taken along the plane III-III of Figure 2; Figure 4 is a cross-sectional view similar to that of Figure 2, showing a lid placed on the neck of a container; Figure 5 is a perspective view showing the lid of Figures 1 to 4 from the outside; Figure 6 is a schematic cross-sectional view showing a lid according to an alternative embodiment, Figure 7 is a bottom view of the lid of Figure 6.

Figures 1 to 5 show a cover 1 suitable for being removably attached to a container for closing an open end thereof. The container that the lid 1 allows Close, it can be a bottle designed to design a liquid, a bottle or a container of another type.

The lid 1 is made of a polymeric material, for example by molding. In particular, the lid 1 can be produced by injection or compression molding, although no other production technologies should be ruled out.

The lid 1 comprises a side wall 2 that extends around a Z axis. In the illustrated example, the side wall 2 is substantially cylindrical.

When the lid 1 is applied to a container neck, the side wall 2 is substantially vertical.

The side wall 2 is provided, on an interior surface thereof, with one or more anchoring elements 3 which allows the lid 1 to be removably fixed to the neck of the container to be closed. In the illustrated example, the anchoring elements 3 comprise a plurality of thread portions suitable for coupling with corresponding threads formed in the neck of the container.

In an alternative embodiment not illustrated, the anchoring elements 3 may have a conformation that differs from the thread portions shown in Figures 1 to 5. For example, the anchoring elements 3 may comprise flanges or cam elements.

The cover 1 further comprises a transverse wall 4 which is arranged in a transverse position, in particular, in a position perpendicular to the axis Z. The transverse wall 4 is substantially flat and has a substantially circular shape when viewed in a plan view.

When the lid 1 is applied to a container neck, the transverse wall 4 is located at a higher height than the side wall 2 to close an open upper end of the container. The transverse wall 4 can then be defined as an upper wall of the lid 1, the adjective "upper" refers to the position of the transverse wall 4 when in use.

A connection zone 5 is provided for connecting the side wall 2 to the transverse wall 4. The connection zone 5 is shown in detail in the amplified portion of figure 2.

The connection zone 5 comprises a first wall portion 6 which is inclined in relation to the side wall 2 and projects towards the interior of the cover 1. The first wall portion 6 extends around the Z axis. The first portion of wall 6 is disposed transversely in relation to the axis Z. The first wall portion 6 projects towards the inside of the lid 1, ie, towards the axis Z, from an upper edge area of the side wall 2.

As shown in Figure 2, the first wall portion 6 has, in the section plane of Figure 2, a substantially flat and straight conformation. In other words, the first wall portion 6 has a conical or circular overall conformation coaxial to the Z axis.

The connection zone 5 further comprises a second wall portion 7 which is interposed between the first wall portion 6 and the transverse wall 4, More particularly, the second wall portion 7 connects with the first wall portion 6 to a peripheral edge of the transverse wall 4.

The second wall portion 7 extends in the same way around the Z axis.

The second wall portion 7 has a different inclination of the first wall portion 6. In particular, the second wall portion 7 may be less inclined, i.e. arranged in a configuration that is closer to a vertical configuration, in comparison with the first wall portion 6. The adjective "vertical" is used here with reference to the position that the lid assumes when applied to a container, in which the Z axis is substantially vertical and the transverse wall 4 is located at a greater height than the side wall 2.

In the illustrated example, the second wall portion 7 is substantially vertical.

The first wall portion 6 has a thickness that is substantially equal to the thickness of the second wall portion 7.

In the lid according to the present invention, the second wall portion 7 of the connection zone 5 makes contact with the external lateral surface of the neck of the container, performing the function that, in known covers, is carried out by a lip of external sealing. The second wall portion 7 of the connecting zone 5 has a greater rigidity than the outer sealing lip of known covers, this due to the presence of the first wall portion 6. In fact, to deform the second wall portion 7 of the lid according to the invention, it is necessary to compress the first wall portion 6 along the direction of the first wall portion 6. As a consequence, thanks to the conformation of the connection zone, the lid in accordance with the invention is capable of effectively counteracting any dilation or bulging of the neck of the container.

The second wall portion 7 is delimited, inside the lid 1 by a sealing surface 8 suitable for coupling with an outer side surface of the neck of the container. The sealing surface 8 may be slightly convex towards the inside of the lid 1, or may have a shape similar to a lip projecting towards the interior of the lid 1, so that it is easier to exert a sealing action when the sealing surface 8 comes into contact with the neck of the container.

The first wall portion 6 and the second wall portion 7 define, on an outer surface of the connection area 5, ie on a surface of the connection area 5 turned towards the outside of the cover 1, a structure of hollow 9 which allows the connection zone 5 to be made lighter compared to the case in which the cover was delimited by an outer profile of the type adopted in known covers.

The hollow structure 9 lightens the connection area on the outside of the top. This allows a reduction of the material necessary to produce a lid, with respect to the known covers having a thicker connection zone.

The hollow structure 9 makes it easier to cool the lid, in cases where the lid is obtained by molding a polymeric material. Actually, the hollow structure 9 prevents an excessive mass of polymeric material from concentrating in the connection zone, which would require a longer cooling time.

Furthermore, the hollow structure 9 maintains the rigidity of the connection zone 5 behind a threshold value on which the lid would become difficult to apply in the full container to be closed. At the end of the industrial filling process, the container can then be easily covered.

In the illustrated example, the hollow structure 9 comprises a plurality of recesses 10 distributed around the Z axis along the connection area 5 on the outside of the lid 1. Therefore a plurality of reinforcement ribs 11 are provided. , which are likewise distributed around the Z axis along the connection zone 5 on the outside of the lid 1.

In other words, the recesses 10 and the reinforcement ribs 11 extend along an edge on the outside of the cover 1, in the connection zone 5 between the side wall 2 and the transverse wall 4.

Each recess 10 is defined between two reinforcement ribs 11. In other words, each reinforcing rib 11 separates two adjacent recesses 10.

The reinforcing ribs 11 have a substantially flat conformation. Each reinforcing rib 11 extends mainly in a plane containing the Z axis. Therefore, the reinforcement ribs 11 are radial ribs.

The reinforcing ribs 11 have a rounded outer profile.

The reinforcement ribs 11 have a thickness that is substantially constant between one rib and another, as well as along each individual rib.

The reinforcing ribs 11 can also be angularly spaced apart.

The reinforcing ribs also improve the rigidity of the connection area, so that the lid is able to resist the expansion or bulging of the neck of the container, without reaching a rigidity that could create a difficulty if the container must be industrially capped .

The recesses 10 can have an angular extension around the Z axis that is equal between a recess 10 and another.

In the recesses 10, the connection zone 5 has an external profile that substantially copies the internal profile of the connection zone 5 that is, of the first wall portion 6 and the second portion of wall 7. In other words, in the recesses 10, the inner profile and the outer profile of the connection zone 5 have substantially the same shape, in particular a corrugated profile projecting towards the interior of the cover and then it joins vertically upwards or almost vertically with the transverse wall 4.

The lid 1 can also be provided with an inner sealing lip 12 of an annular shape, which projects from the transverse wall 4 towards the interior of the lid 1. The inner sealing lip 12 is suitable to be inserted inside the neck of the container to be attached as a seal with the inner side surface of the neck. In particular, the inner sealing lip 12 may be delimited by a convex sealing surface 13 for contacting the inner side surface of the neck of the container.

When the lid is applied in a container, the inner sealing lip 12 ensures a good seal in contact with the inner side surface of the neck of the container. The second wall portion 7 of the connection zone 5 ensures a good seal in contact with the outer side surface of the neck of the container. In this way, it is possible to avoid any exchange of substance between the interior of the container and the environment, or vice versa.

The lid 1 may comprise a connecting element 16, configured as an annular projection projecting from the transverse wall 4 towards the interior of the lid 1. The connecting element 16 is interposed between the sealing surface 8 and the sealing lip interior 12. In other words, the splice element 16 has a diameter that is smaller than the diameter of the sealing surface 8, but larger than the diameter of the inner sealing lip 12.

The connecting element 16 is shorter than the inner sealing lip 12, so that it engages with an upper edge of the neck of the container.

In one embodiment, the splice element 16 can be omitted.

On an outer surface of the side wall 2, grooves 14 may be present to make it easier for both the lid 1 to be applied in a container in an automatic capping line and for the user to hold the lid 1 when the lid of the lid must be removed. container or apply in the container.

The grooves 14 can have the shape of projecting lines projecting from the outer surface of the side wall 2 parallel to the axis Z.

The flutes 14 can also be grouped into two adjacent groups of flutes 14 separated by a smooth portion (ie, without flutes) of the outer surface of the side wall 2 as in the example in FIG. 5. In the example of FIG. Figure 5, the groups of striae 14 are formed by means of three grooves 14.

Alternatively, the flutes 14 can be distributed in a similar way separated around the Z axis.

The grooves 14 can extend as a continuation, along the side wall 2, of all or part of the reinforcement ribs 11. In the latter case, as shown in Fig. 5, the reinforcement ribs 11 from the ribs 11 extending the grooves 14 project towards the outside of the lid 1 more than the other reinforcing ribs 11.

The lid 1 may comprise an obvious tamper ring 17 connected in a breakable manner to a lower edge of the side wall 2, for example, by means of a plurality of bridge elements.

The evident tamper ring 17 may comprise an outer annular portion 18 connected to the side wall 2 and extending below the latter. The tamper evident ring 17 may further comprise an upwardly bent portion 19, connected to the outer annular portion 18 and bent upwardly of the lid 1 to be surrounded by the outer annular portion 18. The bent up portion 19 is suitable for interact with an annular projection arranged on the outside of the neck of the container.

The lid 1 can be made of a polymeric material capable of being molded. In particular, the lid 1 can be made of a polyolefin, in particular of a high density polyethylene (HDPE).

The material used to make the lid 1 can have a melt index that varies between 0.2 and 10/10 minutes, measured at 2.16 kg at 190 ° C in accordance with ISO 1133 or equivalent standards.

The density of the same can vary between 952 and 964 kg / m3, measured in accordance with ISO 1183 or equivalent standards.

The material of the lid 1 can have a single-mode or multimodal molecular distribution.

In one embodiment, the material of the lid 1 is a homopolymer.

Alternatively, the material of the lid 1 may be a copolymer of ethylene and another α-olefin having a number of carbon atoms ranging from 3 to 12.

Figure 4 shows a configuration in which the lid 1 is applied to a container neck 20. In this configuration, the sealing surface 8 of the second wall portion 7 in the connection zone 5 is in contact with a lateral surface outer 21 of neck 20.

The inner sealing lip 12 is disposed within the neck 20, so that the convex sealing surface 13 is in contact with an inner lateral surface 22 of the neck 20.

An upper edge 23 of the neck 20 is spliced against the splice element 16 which, when present, ensures that the neck 20 has penetrated the lid 1 in the correct amount.

The sealing surface 8 and the convex sealing surface 13 prevent any substance inside the container, especially gasses, from leaking into the external environment and at the same time preventing substances in the external environment from entering the container. In this way the integrity and properties of the liquid or other substance present in the container are conserved.

Further, if the neck 20 tends to expand due to, for example, high temperatures or pressure that is generated within the container, the neck 20 is applied to the lid 1 in the connection zone 5, a force that is directed radially outwardly. in relation to the Z axis The lid 1 reacts with a force directed along the first wall portion 6 of the connection zone 5 in the direction indicated by the arrow F in FIG. 4. To deform the cover 1 outwards, the neck 20 must overcome the force indicated by arrow F.

The first wall portion 6 behaves locally like a beam that must be compressed axially so that the neck 20 widens. Therefore, the neck 20 can be widened only after exceeding a considerable resistant force. In most cases, the neck 20 is not able to overcome this resistant force and, therefore, remains substantially without deformation.

In practice, the outer sealing ring present in the lids according to cutting-edge technology, has been replaced in the lid 1 by the sealing surface 8 of the second wall portion 7. For the reasons mentioned above, the second Wall portion 7 is more difficult to deform compared to the outer sealing ring of the known covers. Therefore, the lid 1 is able to more effectively limit the deformations of the neck.

At the same time, the recesses 10 allow the lid 1 to be lighter along an outer edge in which the side wall 2 joins the transverse wall 4.

In this way, when the lid is applied to the neck 20 of the container at the end of the filling process of the industrial container, the connection zone 5 does not behave in an excessively rigid manner and does not create excessive difficulties during the capping step.

In the example thus described up to now, the first wall portion 6 forms an obtuse angle with the side wall 2 of the lid 1. In particular, the angle formed between the first wall portion 6 and the side wall 2 can vary between 90 ° and 150 °.

In a non-illustrated embodiment, the first wall portion 6 can form an angle of 90 ° with the side wall 2. In this case, the first side portion 6 can project towards the interior of the cover 1 in a direction perpendicular to the wall lateral 2.

Alternatively, the first wall portion 6 can form an acute angle, i.e., less than 90 ° with the side wall 2. In this case, the first wall portion 6 could extend into the interior of the cover 1 in a manner that it slopes in a downward direction, that is, towards the evident ring of manipulation 17.

Figures 6 and 7 illustrate an alternative embodiment of a lid 101 for closing a container.

The lid 101 differs from the lid 1 shown in FIGS. 1 to 5 in that it is provided with a reinforcing structure for reinforcing the transverse wall 4. The reinforcing structure comprises a rib arrangement 24 projecting from an interior surface of the wall transverse 4 towards the interior of the cover 101.

In particular, the rib arrangement 24 comprises a plurality of radial ribs 25 extending from a central area towards the inner sealing lip 12. The radial ribs 25 may have a height which, after remaining constant for an initial portion, decreases progressively, approaching the inner sealing lip 12.

The rib arrangement 24 may further comprise an annular rib 26 disposed in a central region of the transverse wall 4. The annular rib 26 may have a circular shape when viewed in a plan view and may be concentric to the transverse wall 4. The radial ribs 25 start from the annular rib 26 and extend radially outwardly from the latter.

In one embodiment, it is possible to provide five radial ribs 25, but more generally, the number of radial ribs 25 can be chosen freely and can be different from five.

The radial ribs 25 provide a rib arrangement 24 of a star-like configuration.

In a non-illustrated embodiment, instead of the radial ribs 25, it is possible to adopt a plurality of ribs that extend over the transverse wall 4 in non-radial directions. It is also possible to omit the annular rib 26.

The rib arrangement 24 allows the rigidity of the transverse wall 4 to be increased to limit the deformations of the transverse wall 4, especially when high pressures are accumulated within the container closed by the lid 101. This can occur frequently, especially in the case of containers containing carbonated drinks.

The other features of the lid 101 are the same as those described above for the lid 1.

In particular, the cover 101 comprises a connection area 5 similar in shape to the connection zone 5 described with reference to FIGS. 1 to 5 and has the same advantages as those explained above for the cover 1. In the connection area 5 , it is possible to identify the first wall portion 6 and the second wall portion 7 in the manner described above with reference to figures 1 to 5. Furthermore, the lid 101 has on an outer surface of the connection area 5, the ribs of reinforcement 11 and holes 10 described above.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. A lid for a container comprising: - a side wall (2) provided with at least one anchoring element (3) for releasably attaching the lid (1; 101) to the neck (20) of the container; - an upper wall (4) arranged transverse to the side wall (2); - a connection zone (5) wherein the side wall (2) is connected to the upper wall (4); wherein the connection zone (5) comprises a first wall portion (6) projecting from the side wall (2) towards the interior of the cover (1; 101) and a second wall portion (7) joining together the first wall portion (6) to the upper wall (4), the first wall portion (6) and the second wall portion (7) define a hollow structure (9) on an outer surface of the connecting zone (5); characterized in that the first wall portion (6) is flat and straight.

2. The lid according to claim 1, further characterized in that the first wall portion (6) has a thickness substantially equal to the thickness of the second wall portion (7).

3. The lid according to claim 1, further characterized in that the second wall portion (7) comprises a sealing surface (8) suitable for sealingly fitting with an outer lateral surface (22) of the neck (20), the first wall portion (6) supports the second wall portion (7) so that to enlarge the diameter of the sealing surface (8), it is necessary to compress the first wall portion (6) in a radial direction in relation to the side wall (2).

4. The lid according to claim 1 or 2, further characterized in that the first wall portion (6) is inclined in relation to the side wall (2).

5. The lid according to any of the preceding claims, further characterized in that the first wall portion (6) forms an angle with the side wall (2) that is greater than or equal to 90 °, and less than or equal to 150 ° .

6. The lid according to any one of the preceding claims, further characterized in that the second wall portion (7) is substantially parallel to the side wall (2).

7. The lid according to any of the preceding claims, further characterized in that the first wall portion (6) and the second wall portion (7) define a recess structure (9) on an outer surface of the connection area (5). ).

8. The lid according to any of the preceding claims, further characterized in that the hollow structure (9) comprises a plurality of recesses (10) distributed along the outer surface of the connection zone (5), a plurality of reinforcement ribs (11) that are provided throughout of said outer surface so that each recess (10) is defined between two consecutive reinforcement ribs (11).

9. The lid according to claim 6, further characterized in that each reinforcing rib (11) has a flat conformation and extends radially in relation to the side wall (4).

10. The lid according to claim 6 or 7, further characterized in that in each recess (10), the first wall portion (6) and the second wall portion (7) have substantially the same thickness.

11. The lid according to any of the preceding claims, further characterized in that a sealing lip (12) having an annular shape projects from the upper wall (4) to engage with an inner side surface (22) of the neck (20) .

12. The lid according to any of the preceding claims, further characterized in that it additionally comprises an annular splice element (16) projecting from the upper wall (4) so that an upper edge (23) of the neck (20) can be spliced against the ring splice element (16).