WO2003011699A1

WO2003011699A1 - Closure cap comprising an internal sealing skirt

Info

Publication number: WO2003011699A1
Application number: PCT/FR2002/002654
Authority: WO
Inventors: Jérémy LE CAM; Frédéric Granier; Yannick Celerier
Original assignee: Bericap
Priority date: 2001-08-01
Filing date: 2002-07-24
Publication date: 2003-02-13
Also published as: FR2828173B1; FR2828173A1

Abstract

The invention concerns a closure cap (1) comprising an end wall (3), a cylindrical skirt (4) including, on its inside, a thread designed to co-operate with an outer matching thread of a container neck, and an internal sealing skirt (13). The inside of the sealing skirt is substantially truncated, and converges from the sealing skirt base towards the free end of the sealing skirt. The inside of the sealing skirt is designed to co-operate with the outside of the neck, the internal diameter of the sealing skirt towards its free end portion being smaller than the external diameter of the neck. The closure cap can also comprise an annular lip (20) designed to improve attachment of a liner to the rim of the neck or contact between the liner and the rim.

Description

PLUG COMPRISING AN INTERNAL SEALING SKIRT

The invention relates to a stopper and a container neck.

The plug has a transverse end wall from which projects a substantially cylindrical outer skirt comprising, on its inner face, a thread intended to cooperate with a complementary external thread of a container neck.

In order to ensure the seal of the cap-neck assembly, several solutions have been envisaged in the prior art.

A first solution is to provide an inner skirt on the stopper, projecting from the end wall, the inner skirt being intended to cooperate with the inner face of the neck of a container.

Such a structure is not entirely satisfactory. In particular, the increase in pressure inside the container results in deformation of the stopper and of the inner skirt, which can lead to a degradation of the contact between the inner skirt and the neck, and, consequently, to a loss sealing.

Furthermore, the presence of the inner skirt does not allow a seal to be placed inside the stopper or on the neck of the container, as will be seen below.

A second solution is to place a seal between the cap and the container neck. Several types of seals can be used.

For example, a seal can be placed at the bottom of the cap, against the end wall. Such a seal can be a foam seal or a seal having gas barrier properties, these seals being made of one or more layers of plastic material (s). When the cap is completely screwed on the neck, the seal is compressed, towards its peripheral zone, between the rim of the neck and the end wall of the stopper, thereby guaranteeing the tightness of the container.

However, even a very small unscrewing of the cap, of the order of a few degrees for example, results in a loss of contact between the rim of the neck and the seal, integral with the cap, the seal then no longer being ensured. This can occur even if the stopper is provided with a tamper-evident band, a weak unscrewing not necessarily leading to the rupture of the bridges between the band and the outer skirt of the stopper, but which can nevertheless cause leakage of the contents of the container .

It is also possible to provide a heat-sealed aluminum seal on the edge of the neck. Such a cap - seal - neck assembly has good sealing performance until the seal has been removed (first seal). On the other hand, once the seal has been removed by a user, the seal, which is no longer ensured except by the plug in contact with the rim of the neck, is less good (second seal).

Indeed, the heat sealing of the aluminum seal on the rim of the neck results in the deposition of adhesive material on the neck, the deformation of the neck, and the degradation of the surface appearance of the neck. Since the heat sealing surfaces are identical to the second sealing surfaces, it is very difficult to obtain good performance in second sealing.

In order to reduce the aforementioned sealing problems, it is not possible to combine the use of a seal and the presence of a sealing skirt cooperating with the inner face of a container neck.

Indeed, to be effective, the inner skirt must have a certain length making it possible to obtain a sufficient contact area with the inner face of the neck. However, the length of the inner skirt is limited by the maximum allowable deformation by the joint. In practice, the maximum admissible deformation by the joint limits the length of the inner skirt to an insufficient value to guarantee a very good seal.

Thus, it is not possible to produce a cap - seal - neck assembly having good sealing performance in which the cap comprises a sealing skirt cooperating with the inner face of a container neck.

A third solution consists in providing the stopper with an internal skirt, projecting from the end wall, and intended to cooperate with the external face of the neck of a container.

Such plugs are for example described in the documents EP 0 529 383, DE 198 20 266 and EP 0 293 901.

The documents EP 0 529 383 and DE 198 20 266 describe plugs provided with an internal substantially cylindrical sealing skirt, and further comprising an internal bead at the junction between the external skirt and the transverse wall. These caps are particularly intended for receptacles containing carbonated drinks, the objective to be achieved being to avoid the escape of gases.

When the stopper is screwed onto a container neck, the skirt cooperates with the outside face of the neck and is deformed very significantly against the rim and the outside surface of said neck, said skirt also being crushed against the inner bead of the stopper.

These plugs have a number of drawbacks.

First, in order to be able to be deformed significantly, the skirt must be made of a relatively flexible material. However, the skirt being molded in one piece with the other parts of the stopper, it follows that the stopper cannot be made of a very rigid material. However, the rigidity of the cap may be necessary nnur nfirtainps annlimtinnç In addition, the skirt is highly stressed by the deformation which it undergoes, which can harm its robustness and its lifespan, or not make it possible to ensure an excellent neck-cap seal for a long time. Finally, it is necessary to modify the inner face of the cap compared to traditional caps because of the presence of the bead

As for document EP 0 293 901, it describes a stopper provided with a frustoconical inner skirt diverging from its base towards its free end.

This structure does not make it possible to obtain, by elasticity, a plating of the skirt against the outside face of the neck.

As a result, the seal can only be obtained via a significant deformation of the skirt, which results in stresses on said skirt, which can in particular affect the quality of the seal, as indicated above.

The object of the invention is to provide a standard plug allowing excellent performances of first and second seals to be obtained, whatever the use of said plug, and in particular: with or without seal, with a seal placed at the bottom. of the cap, with a heat-sealed seal on the rim of the neck of a container.

Thus, according to a first aspect, the invention relates to a plug of the type comprising a transverse end wall from which protrude, in the same direction, on the one hand, a substantially cylindrical outer skirt comprising, on its inner face, a thread intended to cooperate with a complementary external thread of a container neck, and, on the other hand, an internal sealing skirt, the internal face of the sealing skirt - located opposite the axis of the cap - being intended to cooperate with the outside face of the neck and the inside diameter of the sealing skirt towards its free end portion being less than the outside diameter of the neck. According to the invention, the inner face of the sealing skirt is substantially frustoconical, and converges from the base of the sealing skirt towards the free end of the sealing skirt, and the inside diameter of the skirt sealing towards its base is substantially equal to the outside diameter of the neck. In this way, first of all, the increase in pressure inside the container does not lead to a deterioration of the seal. On the contrary, the deformation of the stopper and of the inner seal skirt leads to a reinforcement. contact between the inner skirt and the collar, which improves sealing.

Furthermore, the height of the sealing skirt is sufficient so that, when the cap is unscrewed by a few degrees, without breaking the bridges connecting the tamper-evident band to the cylindrical skirt, the inner skirt is always in contact with the face. outside of the neck, thus ensuring the preservation of the seal. The cap thus has an “anti-sabotage” function.

Also, the second seal is provided by the inner skirt, in contact with the outer face of the neck. The collar rim, which can be a heat-sealing surface, is not used as a second sealing surface.

Finally, taking into account the respective dimensions of the inner skirt and the container neck, the skirt is not significantly deformed, while ensuring excellent contact with the outer face of the neck. Consequently, a very good seal is obtained without the risk of damaging the inner skirt of the plug.

In one possible embodiment, the inner face of the sealing skirt is inclined relative to the axis of the plug at an angle between 0 ° and 10 °.

The sealing skirt may have, towards its free end portion, an inclined inner chamfer so that the sealing skirt has, at its end, an inside diameter greater than the outside diameter of the neck.

The outer face of the sealing skirt can also be substantially frustoconical, and converge from the base of the sealing skirt in the direction of

IΑγtr <âmitή lihr e la ii ino H'όtnnohόitό According to a possible embodiment, the plug further comprises a substantially discoidal seal, of diameter less than the inside diameter of the sealing skirt towards its base, the said seal being placed inside the sealing skirt and held against the end wall of the plug by the taper of the sealing skirt.

The seal may be a heat sealable aluminum seal, a foam seal, or a seal having gas barrier properties.

According to other characteristics, the plug further comprises an annular lip projecting from the end wall in the same direction as the cylindrical skirt, with an axis substantially coincident with the axis of the plug, the diameter of said lip and its length being respectively less than the inside diameter at the base and the length of the sealing skirt, and being such that, when the cap is screwed onto a container neck, the lip is located opposite the rim of said neck. The lip is intended to improve the joining of a seal placed at the bottom of the stopper, in contact with said lip, at the edge of said neck and / or to improve the contact between said seal and the edge of neck.

According to a second aspect, the invention relates to a container neck comprising a thread on its outer face, and intended to cooperate with a stopper as previously described.

The joint plane of such a neck substantially orthogonal to the axis of the neck, formed during the molding of said neck, is located at a distance from the edge of the neck large enough so that, when the cap is completely screwed onto the neck, the parting line is located beyond the contact zone between the sealing skirt and the outside face of the neck relative to the rim of said neck, so that the sealing between the skirt and the neck is not impaired .

Finally, according to a third aspect, the invention relates to an assembly comprising a plug as previously described and a container neck comprising a thread on its outer face,

Hn fïie-tαπc. inside the cap, this assembly being such that, when the cap is completely screwed onto the container neck, the inside face of the sealing skirt has a substantially cylindrical, or slightly frustoconical shape, converging from the base of the skirt. sealing towards the free end of the sealing skirt.

The other characteristics of the invention result from the following description of an embodiment, description made with reference to the appended figures in which: - Figure 1 is a view in partial radial section of a plug according to the invention;

- Figure 2 is an enlarged view of detail A of Figure 1;

- Figure 3 is a partial view in radial section of the cap of Figure 1, provided with a seal; - Figures 4a and 4b are perspective views of aluminum seals that can be used with the plug of Figure 1;

- Figure 5 is a partial radial sectional view of the cap of Figure 3, provided with a seal, fully screwed onto a container neck;

- Figure 6 is a view similar to Figure 5, the plug having no or no more seal;

- Figure 7 is an enlarged view of detail B of Figure 6;

- Figure 8 is an elevational view of a container neck intended to cooperate with the cap of Figures 1 or 3;

- Figure 9 is an enlarged view of detail C of Figure 8, showing a joint plane of the neck.

First of all, reference is made to FIG. 1 which represents a plug 1, of axis 2, the plug 1 being for example made of plastic.

The plug 1 firstly comprises a transverse end wall 3, which is substantially discoidal, as well as a substantially cylindrical skirt 4 projecting substantially perpendicular to the transverse wall 3. The cylindrical skirt 4 has, on its outer face 5, notches 6 intended to facilitate the screwing and unscrewing of the plug 1 by a user, and, on its inner face 7, a thread 8 intended to cooperate with the external thread of a container neck. The plug 1 also comprises a tamper-evident band 9, connected to the free end 10 of the cylindrical skirt 4 by frangible bridges 11 or by a line of weaker resistance. The tamper-evident band 9 comprises hooking projections 12, directed towards the axis 2 of the stopper 1, and intended to cooperate with the neck of a container to ensure the maintenance of the tamper-evident band 9 at the neck of the said container when, during the first opening of the container, the bridges 11 are broken.

In addition, the plug 1 comprises an inner sealing skirt 13 flexible, projecting from the transverse wall 3 in the same direction as the cylindrical skirt 4.

The sealing skirt 13 comprises an internal face 14, situated opposite the axis 2 of the plug 1, and an external face 15, situated opposite the cylindrical skirt 4.

As illustrated in FIG. 2, the internal face 14 of the sealing skirt 13 is substantially frustoconical, and converges from the base 16 of the sealing skirt 13 in the direction of the free end 17 of the sealing skirt 13 Said inner face 14 is inclined relative to the axis 2 of the plug 1 at an angle α between 0 ° and 10 °.

The outer face 15 of the sealing skirt 13 is also substantially frustoconical, and converges from the base 16 of the sealing skirt 4 in the direction of the free end 17 of the sealing skirt 13.

The angle of which the outer face 15 of the sealing skirt 13 is inclined may be greater than, substantially equal to, or less than the angle α. In addition, the sealing skirt 13 has, towards its free end portion 18, an internal chamfer 19.

The inner face 14 of the sealing skirt 13 is intended to cooperate with the outer face of a container neck. To this end:

- The inside diameter of the sealing skirt 13 towards the free end 17 of said sealing skirt 13 (Di- |) is greater than the outside diameter De of the neck, due to the inclination of the chamfer 19;

- The inside diameter of the sealing skirt 13 towards the free end 18 of said sealing skirt 13 (Di-is) is less than the outside diameter De of the neck.

In addition, the internal diameter Diι ₆ of the sealing skirt 13 towards its base 16 is substantially equal to the external diameter De of the neck 22.

As a variant, the internal diameter Di ₁₆ of the sealing skirt 13 towards its base 16 may be slightly greater or slightly less than the external diameter De of the neck 22, provided that, when the plug 1 is screwed onto the neck 22, d 'On the one hand, the sealing skirt 13 does not undergo a significant deformation and, on the other hand, the contact between the sealing skirt 13 and the neck 22 is perfectly ensured.

The length of the sealing skirt 13, between its base 16 and its free end 17, is between 1 and 5 mm, in particular of the order of 2 mm.

The plug 1 also comprises an annular lip 20, of axis substantially coincident with the axis 2 of the plug 1, and projecting from the end wall 3 in the same direction as the cylindrical skirt 4.

The diameter of the lip 20 is less than the inside diameter at the base 16 of the sealing skirt 13 (Diι ₆ ), and the length of the lip 20 is less than the length of the sealing skirt 13. The lip 20 is located so as to be opposite the rim of the container neck when the cap 1 is screwed onto said neck. Finally, the plug 1 may comprise a substantially discoidal seal 21, of diameter less than the internal diameter Diiβ of the sealing skirt 13 towards its base 16 (see FIG. 3).

The seal 21 is placed against the transverse wall 3 of the plug 1, in contact with the lip 20, inside the sealing skirt 13, that is to say in the space situated around the axis 2 of the plug 1 and delimited by the sealing skirt 13. The seal 21 is held against the end wall 3 of the plug 1 by the taper of the sealing skirt 13.

The seal 21 can be a heat sealable aluminum seal, a foam seal, or a seal having gas barrier properties.

Referring now to Figure 8 which shows a container neck 22 with which the plug 1 is intended to be associated.

The neck 22 is substantially cylindrical, of axis 23, has an annular rim 24 and defines an opening 25. The neck 22 has a seat 26 and a flange 27, located parallel and at a distance from the seat 26 on the side of the rim 24 of the neck 22. The neck 22 also comprises, on its outer face 28, a thread 29 - comprising for example three threads - projecting towards the outside of the neck 22.

The neck 22 has an outer diameter De, defined as the diameter of the outer cylindrical face 28 of the neck 22, without taking into account the thread 29 (see FIG. 8).

For the molding of the neck 22, three molds are generally used:

a first fixed mold makes it possible to produce the upper part of the neck 22, the external face 28 of the neck 22 comprising, towards the rim 24, a part having, in radial section, the shape of a quarter of a circle 30, extended by a substantially cylindrical portion 31 of low height (see Figure 9);

- a second mold, composed of two movable half cylinders allowing the During manufacture, a slight offset generally exists between the first and second molds, this offset leading to a small difference in outside diameter ΔDe of the neck 22 between the upper part of the neck 22, formed by the first mold, and the rest of the neck 22, formed by the second mold.

The neck 22 thus comprises a joint plane P substantially orthogonal to the axis 23 of the neck 22, corresponding to the junction zone of the first and second molds.

The invention provides for modifying the molds so that the joint plane P is located at a distance from the rim 24 of the neck 22 which is sufficiently large so that, when the plug 1 is completely screwed onto the neck 22, the joint plane P is located beyond the contact zone between the sealing skirt 13 and the outer face 28 of the neck 22 with respect to the rim 24 of the neck 22.

For example, the joint plane P is located more than 1.8 mm from the edge 24 of the neck 22.

The cooperation between the plug 1 and the neck 22 is now described.

When the cap 1 is screwed onto the container neck 22, the sealing skirt 13 is initially positioned outside the neck 22, since, towards its free end 17, the sealing skirt 13 has an internal diameter Diι ₇ greater than the outside diameter De of the neck 22.

When the screwing is continued, the rim of the neck comes into contact with the inclined face of the chamfer 19, then slides along the inner face 14 of the sealing skirt 13, gradually deforming the sealing skirt 13, the angle of inclination α of the inner face 14 of the sealing skirt 13 decreasing.

When the cap 1 is completely screwed onto the neck of the container, as illustrated in FIGS. 5 to 7, the internal face 14 of the sealing skirt 13 has from the base 16 of the sealing skirt 13 in the direction of the free end 17 of the sealing skirt 13.

The sealing skirt 13 is then in contact, at least towards the free end portion 18 of the sealing skirt 13, with the external face 28 of the neck 22.

The movement of the sealing skirt 13 when the plug 1 is screwed onto the neck 22 is similar to a pivoting around the base 16 of said sealing skirt 13, the skirt retaining its general shape without being crushed.

Because of its elasticity, the sealing skirt 13 exerts on the external face 28 of the neck 22 a substantially radial force, directed towards the axis 2 of the plug 1, thus ensuring the seal between the neck 22 and the plug 1.

The joint plane P of the neck 22 being situated beyond the contact zone between the internal face 14 of the sealing skirt 13 and the external face 28 of the neck 22, the external diameter of the neck 22 in the contact zone is always De, and does not vary by ± ΔDe. The dimensions, positioning and flexibility of the sealing skirt 13, determined for a neck 22 with an outside diameter De, are therefore always optimal, so that the seal between the sealing skirt 13 and the neck 22 does not is not altered.

Thus, even in the absence of a seal 21, the neck-plug assembly has a very good seal (case of Figures 6 and 7).

The angle α with which the inner face 14 of the sealing skirt 13 is inclined is large enough to guarantee good sealing and small enough so that the unscrewing of the plug 1 does not require too great a torque.

The invention also provides to provide the plug 1 with a seal 21, as previously described. During manufacture, the plug 1 is mounted by screwing on the neck 22. In the case of a foam seal or having gas barrier properties, the seal 21 is simply placed at the bottom of the plug 1, the seal 21 remaining integral with the plug 1 when a user unscrews the plug 1.

When the plug is completely screwed onto the neck 22, the seal 21 is compressed, towards its peripheral zone, between the rim 24 of the neck 22 and the end wall 3 of the plug 1 (FIG. 5). The lip 20 improves the contact between the seal 21 and the rim 24 of the neck 22.

Thus, the seal is ensured both by the seal 21 and by the seal skirt 13. If the plug 1 is slightly unscrewed, the seal 21 is no longer in contact with the flange 24 of the neck 22. However, the inner face 14 of the sealing skirt 13 is always sufficiently in contact with the outer face 28 of the neck 22 to guarantee the tightness of the assembly.

In the case of an induction sealable aluminum seal on the neck 22 of a container, the seal 21 is initially placed at the bottom of the plug 1, against the lip 20.

As illustrated in FIGS. 4a and 4b, the seal 21 comprises a cover part 32, intended to cover the opening 25 of the neck 22, and a tongue 33, allowing a user to remove the heat-sealed seal 21 on the neck 22 by pulling on said tongue 33. The tongue 33 may constitute an extension of the cover part 32 (FIG. 4b, “pull tab”) or be attached to one face of the cover part 32 (FIG. 4a, “top tab”). ).

The seal 21 comprises, in addition to a layer of aluminum, a layer of adhesive, which can be located only on the peripheral zone of the cover part 32, in order to heat seal the seal 21 at the edge 24 of the neck 22. When the seal 21 is placed against the end wall 3 of the plug 1 and the lip 20, the layer of adhesive is directed towards the tamper-evident band 9.

During assembly, the plug 1 provided with the seal 21 is screwed onto the neck 22, so

That the Joint IS in contact with one? narï avfir: the lip 90 t rl'αnt nαrf αυoo lo rim 24 of the neck 22. The plug 1 is then placed under an induction head to heat-seal the seal 21 at the rim 24 of the neck 22, via the lip 20. This gives the cap-seal - neck assembly shown on Figure 5.

During the first opening, a user unscrews the plug 1, causing the frangible bridges to rupture 11. By gripping the tongue 33 and pulling on it, he unseals the seal 21 from the neck 22, thus freeing the opening 25.

When the plug 1 is again screwed onto the neck 22, the second seal will be provided only by the sealing skirt 13 (Figures 6 and 7). Thus, the deposition of adhesive on the rim 24 of the neck 22 and other degradation resulting from the heat sealing of the seal 21 do not harm the quality of the second seal.

Claims

1. A plug of the type comprising a transverse end wall (3) from which protrude, in the same direction, on the one hand, a substantially cylindrical outer skirt (4) comprising, on its inner face (7), a thread ( 8) intended to cooperate with a complementary external thread (29) of a container neck (22), and, on the other hand, an internal sealing skirt (13), the internal face (14) of the skirt d 'seal (13) - located opposite the axis (2) of the plug (1) - being intended to cooperate with the outer face (28) of said neck (22), the inner diameter (Diiβ) of the skirt d sealing (13) towards its free end part (18) being less than the outside diameter (De) of the neck (22), characterized in that the inside face (14) of the sealing skirt (13) is substantially frustoconical, and converges from the base (16) of the sealing skirt (13) towards the free end (17) of the sealing skirt (13), and in that e the inside diameter (Di-iβ) of the sealing skirt (13) towards its base (16) is substantially equal to the outside diameter (De) of the neck (22).

2. Cap according to claim 1, characterized in that the inner face (14) of the sealing skirt (13) is inclined relative to the axis (2) of the cap (1) by an angle (α) between 0 ° and 10 °.

3. Plug according to claim 1 or 2, characterized in that the sealing skirt (13) has, towards its free end portion (18), a chamfer (19) inclined inside so that the sealing skirt (13 ) has, towards its end (17), an inside diameter (Di- | ₇ ) greater than the outside diameter (De) of the neck (22).

4. Plug according to any one of claims 1 to 3, characterized in that the outer face (15) of the sealing skirt (13) is substantially frustoconical, and converges from the base (16) of the skirt sealing (13) towards the free end (17) of the sealing skirt (13).

5. Plug according to any one of claims 1 to 4, characterized in that the sealing skirt (13) has a length between 1 and 5 mm, in particular of the order of 2 mm.

6. Plug according to any one of claims 1 to 5, characterized in that it further comprises a seal (21) substantially disc-shaped, of diameter less than the internal diameter {DQ) of the sealing skirt (13) towards its base (16), the said seal (21) being placed inside the sealing skirt (13) and held against the end wall (3) of the plug (1) by the taper of the skirt d seal (13).

7. Cap according to claim 6, characterized in that the seal (21) is a heat sealable aluminum seal, a foam seal, or a seal having gas barrier properties.

8. Stopper according to any one of claims 1 to 7, characterized in that it comprises an annular lip (20) projecting from the end wall (3) in the same direction as the cylindrical skirt (4), of axis substantially coincident with the axis (2) of the plug (1), the diameter of said lip (20) and its length being respectively less than the inside diameter at the base (D β) and the length of the skirt sealing (13), and being such that, when the stopper (1) is screwed onto a container neck (22), the lip (20) is located opposite the rim of said neck (22), said lip (20) being intended to improve the joining of a seal (21) placed at the bottom of the plug (1), in contact with said lip (20), at the rim (24) of said neck (22) and / or improve the contact between said seal (21) and the rim (24) of the neck (22).

9. container neck comprising a thread (29) on its outer face, and intended to cooperate with a plug (1) according to any one of claims 1 to 8, characterized in that the joint plane (P) of the neck (22) substantially orthogonal to the axis (23) of the neck (22), formed during the molding of said neck (22), is located at a distance from the flange (24) of the neck (22) sufficiently firanHA nm ir πi lA IΠΓ ΠI IO the »

the parting line (P) is located beyond the contact zone between the sealing skirt (13) and the external face (28) of the neck (22) relative to the flange (24) of said neck (22 ), so that the seal between the skirt (13) and the neck (22) is not impaired.

10. Neck according to claim 9, characterized in that the joint plane (P) is located more than 1.8 mm from the edge of the neck (22).

11. An assembly comprising a plug (1) according to any one of claims 1 to 8 and a container neck (22) comprising a thread (29) on its outer face (28), complementary to the inner thread (7) of the plug (1), characterized in that, when the cap (1) is completely screwed onto the container neck (22), the internal face (14) of the sealing skirt (13) has a substantially cylindrical shape, or slightly frustoconical, converging from the base (16) of the sealing skirt (13) towards the free end (17) of the sealing skirt (13).