[0001]. The present invention relates to a closure for liquid containers such as, particularly though not limited to, a stopper for sparkling wine or champagne bottles.

[0002] With reference to sparkling wine and champagne, bottle closures are at present typically obtained either by means of natural cork stoppers, or stoppers obtained by mixtures of corks of different types with other natural materials.

[0003] A number of disadvantages have been observed concerning the use of stoppers comprising cork. In fact, both natural cork and mixtures thereof have properties that vary over time such as, colour, drying, shrinkage or expansion, crumbling and adhesion to the bottle neck wall. Particularly, cork can give a characteristic odour to the wine thereby making it unsuitable for trade. Furthermore, upon uncorking a bottle, for example, of sparkling wine or champagne, the pressure manually applied to the stopper may lead to the crumbling or breakage of the same. It may also happen that the pressure inside the bottle (which may reach 7-8 atmospheres) creates, during the uncorking operation, an

explosion with a consequent uncontrolled ejection of the stopper.

[0004] A number of the above problems have been partially solved by stoppers made of synthetic materials (for example, made of thermoplastic resins) , which ensure more consistency in terms of quality and seal in the introduction area of the stopper over time. Furthermore, synthetic materials provide a tightness of the closure of a higher level than that obtainable by means of cork or mixtures thereof, without the steps of inserting and uncorking the stopper becoming more complicated. Particularly, stoppers of synthetic material are known having cylindrical or mushroom shapes. [0005] However, it has been noted that a synthetic stopper, when applied to the bottle and fixed thereto by the conventional wire cap or metal frame, does not provide a level of tightness that is sufficient, and particularly, adequate to the possibilities potentially offered by the material of which it is made. [0006] It has been observed that incomplete tightness can be associated to those deformations of the stopper occurring upon inserting the same into the bottle, and that not only are not eliminated by applying the metal frame, but on the contrary can be enhanced by the latter. [0007] The object of the present invention is to

provide a closure for liquid containers ensuring a tightness level, particularly, in the vicinity of the stopper insertion mouth, which is higher than that offered by conventional closures. [0008] The object of the present invention is achieved by a closure made according to the annexed claim 1. Embodiments of said closure are as defined in the dependent claims 2 to 20. The object of the present invention is also a bottle such as described in claim 21 and a sealing method for a bottle such as defined in claim 22. Particular embodiments of the sealing method for the bottle are as defined in claims 23-25. [0009] Further characteristics and the advantages of the present invention will be understood from the following description of some preferred embodiments thereof, which is given by way of non-limiting example, with reference to the attached figures, in which: figures 1 and 2 show perspective and side views of a first closure made according to a first embodiment of the present invention, respectively; figures 3A, 3B, 3C show, again, a side view of the first closure, a side view of the first closure inserted into a bottle neck, and a longitudinal sectional view of the first closure and the neck from figure 3B, respectively;

figures 4 and 5 show a perspective view and a side view of a second closure made in accordance with a second embodiment of the present invention, respectively; figures 6A, 6B, 6C show, again, a side view of the second closure, a side view of the second closure inserted into a bottle neck, and a longitudinal sectional view of the second closure and the neck from figure 6B, respectively. [0010] Figures 1 and 2 show a first closure 1 for liquid containers, in accordance with a first exemplary embodiment of the present invention. Particularly, the first closure 1 is a stopper for bottles that are intended to contain a liquid, preferably a sparkling one. The first closure 1 (hereinafter, the first stopper 1) is such as to be partially inserted into a mouth of the bottle and is suitable, particularly though not exclusively, for closing bottles containing sparkling wine and/or champagne. [0011] It should be observed that for the purposes of the present invention, with the term "sparkling" is meant both a liquid to which the gas is artificially added (for example, carbon dioxide added by bubbling) , and a liquid in which the gas amount is due to natural phenomena (such as the "bubbles" of sparkling wine) . [0012] The first stopper 1 shown in figures 1 and 2

has an outer shape of a substantially cylindrical type, with a longitudinal axis A-A' . This first stopper 1 comprises an annular region 2, that is transversal (particularly, orthogonal) to the longitudinal axis A-A' , an upper portion 3 and a lower portion 4 being joined thereto. According to the example, the annular region 2 occupies a middle position relative to the longitudinal axis A-A' and the upper 3 and lower 4 portions are counter-posed to the annular region. [0013] The annular region 2 includes at least one notch 5 that, according to the example illustrated, is a continuous annular groove orthogonal to axis A-A' . The groove 5 is joined to the upper 3 and lower 4 portions. [0014] As may well be seen from figure 2, the groove 5 has surface discontinuities relative to the upper portion

3 and relative to the lower portion 4. In other words, a bottom 6 of groove 5 (i.e. the groove wall having minimum radius r) is joined to the upper portion 3 by means of a first joining wall 7 having a radius R7 that varies when moving along the outer surface of first stopper 1. Furthermore, this bottom 6 is joined to the lower portion

4 by means of a second joining wall 8 having a radius R8 that also varies when moving along the axis A-A' .

[0015] The discontinuities of the joint with upper portion 3 and lower portion 4 are indeed associated with

the variability of the radius of both joining walls 7 and 8. Alternatively to the continuous annular groove 5, there can be used a plurality of separate notches or grooves being obtained in the annular region 2. [0016] The upper portion 3 and the lower portion 4 comprise a first main body 9 and a second main body 10, respectively, both of them being substantially cylindrical and joined to the groove 5 by means of said joining walls 7 and 8. According to a first embodiment illustrated in figures 1 and 2, the first and second main bodies 9 and 10 substantially have the same maximum radius R. The first 9 and second 10 main bodies have substantially smooth outer walls and, particularly, are not provided with threadings because the first stopper 1 is not of the type to be introduced by screwing.

[0017] Furthermore, the upper 3 and lower 4 portions comprise a beveled first end 11 and second end 12, respectively (particularly, of a troncoconical shape) relative to the first 9 or second 10 main bodies, to which they are respectively joined. According to the first embodiment described above, the upper 3 and lower 4 portions are mirror-like relative to the groove 5 and the first stopper 1 is, therefore, of a symmetrical type. [0018] The material used for manufacturing the first stopper 1 is such as to give advantageous characteristics

of elasticity, permeability, seal and, advantageously, also of elastic memory, to the stopper. According to the preferred embodiment, the first stopper 1 can be made of a synthetic material. For example, thermoplastic materials and, particularly, thermoplastic resins or mixtures thereof such as, for example, resins that are already known in the field of wine stoppers. Particular examples of thermoplastic materials are: styrene- butadiene resins, styrene-butadiene-styrene or styrene- isoprene-styrene block copolymers, optionally hydrogenated (SBS, SIS, SEBS, SEPS) ; EVA copolymers; expanded polyethylene or polypropylenepolyethylene; polyisoprene. A plastic material for use with the present invention is the metallocene linear low-density (MLLDPE) , that is a 1-octene plastomer.

[0019] Advantageously, to the materials used there can be added blowing agents of physical/chemical origin and dyes. The first stopper 1 can be obtained by injection or extrusion, with or without subsequent mechanical working. [0020] The advantages offered by the first stopper 1, are well emphasized by the bottling process that can be of the automatic type. Figures 3A-3C relate to the insertion of the first stopper 1 within the mouth 13 of neck 14 of a bottle (not shown in full) . Figures 3B and 3C show the neck 14 of the bottle closed by the stopper

1, and a longitudinal section thereof, respectively. Figure 3A shows the first stopper 1 in a rest configuration (i.e., not inserted within the bottle and without external stress) and, by confronting the same with figures 3B and 3C, it underlines the level that groove 5 will assume relative to mouth 13 after the stopper has been inserted within the neck 14. [0021] Bottling, i.e. the proper insertion of part of the stopper 1 in the neck 14 of a bottle, can be carried out by means of a conventional bottling apparatus (not shown) provided with jaws, of a thrust punch and means for applying an outer wire cap.

[0022] The bottling process comprises a first step where the first stopper 1 is hold tight between the jaws exerting a radial compression on the first stopper 1 such as to determine a complessive reduction of its radial size and a consequent elongation of the stopper (i.e. particularly, its upper 3 and lower 4 portions) in both directions of the longitudinal axis A-A' . This compression leads to the reduction of the maximum radius

R for the first stopper 1 to be inserted in the mouth 13.

[0023] Subsequently to the compression step, the stopper 1 is partially inserted into the neck 14 of the bottle by means of a thrust force substantially exerted along the longitudinal axis A-A' by the punch of the

bottling apparatus. Upon insertion, the first stopper 1, still being in the compressed step, is brought into the neck 14 such that the lower portion 4 will be completely within the neck 14 and the middle region 2 will be near the mouth 13 of the neck 14. The groove 5 will move near the mouth 13 and, for example, extend partially outside and partially inside the neck 14.

[0024] After the lower portion 4 has been inserted into the neck 13, a release step is carried out in which the radial compression applied to the jaws will cease, i.e. the jaws are opened and the stopper 1 is released. As a consequence of the release, the stopper 1 portion being inside the neck 14 (including the lower portion 4) expands due to the elastic effect, thereby adhering, for a good part, to the inner wall of neck 14. Upon releasing, the jaws also cause the portion of stopper 1 outside the neck (including the upper portion 3) to expand (due to an elastic effect) . [0025] In case of sparkling wines and champagne, subsequent to the release, there is carried out an advantageous step of applying a wire cap or outer frame being typically made of metal, and that is not shown because it is of a conventional type. This outer frame envelops the beveled upper end 11 and the upper portion 3 of the first stopper 1 and is locked to outer ribs 15 of

the neck 14. The outer frame is fixed such as to exert a suitable longitudinal force on the first stopper 1 that, besides ensuring that the latter is held in position, causes a better adhesion of the outer part of the first stopper 1 to the mouth walls 13.

[0026] As an experiment, it has been observed that, as a consequence of the release step, and even before applying the outer frame, the first stopper 1 has a considerable level of adhesion to the inner and outer walls of mouth 13, thereby providing an optimum closure.

[0027] As may be seen in the figure 3B (relative to the step subsequent to release) the lower portion 4 adheres to the inner walls of neck 14 and the groove 5 is deformed such that it cannot be distinguished any longer. It should be also noted that, even though it may occur that the adhesion to the walls of mouth 13 is not perfect after release, nevertheless this is better than that obtained with those conventional stoppers made of cork or synthetic material that are not provided with any groove. [0028] Furthermore, it has been observed that by applying the outer frame, the adhesion level of the first stopper 1 to the walls of mouth 13 does not get worse, but is often improved, contrary to what happens with conventional stoppers made of cork or synthetic material. [0029] A possible reason for the increase in the

adhesion level being offered by the first stopper 1 is described as follows. As a consequence of the relase of the jaws, the portion of the first stopper 1 being compressed within the neck 14 (and that is hence elongated relative to the rest position indicated in figure 3A) would tend to transmit this deformation stress (particularly, elongation) also to the portion of the first stopper 1 being outside the neck 14. If the upper part (including the portion 3) of the first stopper 1 were elongated as a consequence of the compression by the lower part, the annular region 2 of the stopper would not adhere to the walls of mouth 13 and, by applying the outer frame, undesired deformations and creases of the stopper in that region would be formed. It is believed that the presence of groove 5 reduces or prevents that the elongation stress may be transmitted from the part of stopper 1 inside the neck to that outside the neck. [0030] Consequent to the presence of groove 5, there occur two phenomena having positive effects. In fact, the part of stopper 1 being outside the neck 14 is more free to expand and adhere to the upper parts of the mouth 13 without considerable deformations. Furthermore, the radial stress is focused on that portion of the first stopper 1 being inserted within the neck 13, thereby

improving the adhesion thereof to the walls. [0031] Finally, when applying the outer frame, the outer part of the stopper 1 is pushed towards the mouth 13 such as to adhere even better to the outer wall of the mouth, thereby ensuring tightness as desired, substantially without causing the formation or enhancement of creases that would compromise the sealing. [0032] It should be noted that the particular first stopper 1, such as represented in figures 1-3C, is of a symmetrical type and offers the advantage that both upper 3 and lower 4 portions can be inserted within the neck 14 of the bottle. The symmetry of stopper 1 facilitates automatic bottling, which does not require any operation of stopper orientation. [0033] Figures 4, 5, 6A-C show a second stopper 20, similar to the first stopper 1 described above, and made according to a variant embodiment of the present invention. In figures 4-6C, components and portions similar or identical to those already described are designated with the same numerals.

[0034] This second stopper 20 differs from the first stopper 1 in that its lower portion 4 (the one to be inserted within the neck 14) has a maximum diameter R' lower than the maximum diameter R of the upper portion 3. Particularly, the size of the bottle neck being equal,

the lower portion 4 of the second stopper 20 can have a radius R' lower than the radius R of the lower portion 4 of first stopper 1. Having a reduced radius R' (though still such as to interfere with the radium of mouth 13) , advantageously, allows to further reduce deformation upon bottling and facilitate the stopper extraction when the bottle is being uncorked.

[0035] The bottling method with the second stopper 20 is similar to that described above for the first stopper 1 except that the second stopper 10 is required to be properly oriented before the lower portion 3 is inserted into the neck 13. The same considerations made for the first stopper 1 are also valid for the second stopper 20, therefore they will not be repeated. [0036] It should be observed that (for both types of stoppers described) the groove 5 can have different sizes and, for example, with reference to figure 2: a length L ranging from 1 to 4 mm, a depth P ranging from 1 to 5 mm, Furthermore, different geometries are possible for the groove 5, which can have, for example, a U-, C- or V- shaped section. The groove 5 can be provided either in the midline of first stopper (1 or 20) , or it can be offset relative to the midline, for example, within ± 15 mm from the midline.

[0037] For example, the size of first stopper 1 (figure 2) can be: maximum radius R ranging from 12,5 mm to 17,5 mm; total length 1 ranging from 30 mm to 50 mm. For example, the size of second stopper 20 (figure 5) can be:

- maximum radius R ranging from 12,5 mm to 17,5 mm; radius R' of lower portion ranging from 10,5 mm to 15,5 mm,- - total length 1 ranging from + 30 mm to 50 mm.

The above exemplary values relate to the neck of a bottle of sparkling wine or champagne of the conventional type and with a mouth 13 having an inner diameter typically equal to 17,5 mm - 18 mm. Those skilled in the art, based on the description above, can select the size for the stopper suitable for any other particular size of the bottle being used.

The present invention is particularly advantageous in that, such as described above, it allows to obtain a greater adherence of the stopper to the walls of mouth 13 than would be obtained with conventional stoppers due to reduction or elimination of the creases as well as deformations in the intended region. The reduction or elimination of creases and deformations also entails a better visual appearance of the bottle with the stopper.

[0038] Furthermore, by employing the stopper of the present invention, the application of the outer frame being anchored to the bottle neck 14 can occur by applying a lower force than that required for this operation with conventional stoppers. This is because a great increase in the adherence by means of the frame is not required, a satisfactory adherence being already obtained after the stopper has been released by the jaws. [0039] Due to the high level of adherence that can be obtained in the region of the mouth 13 of neck 14, the stopper in accordance with the invention has a maximum tolerable pressure, without the stopper being ejected from the bottle, higher than those obtainable with the stoppers provided by the prior art. For example, while the maximum tolerable pressure is of 7-8 atm with conventional stoppers, by employing a stopper in accordance with the invention the maximum tolerable pressure can be as high as 12 atm. Particularly, this maximum tolerable pressure ranges from 8 atm to 12 atm, more particularly, from 8,5 atm to 12 atm and still more particularly from 9 atm to 12 atm.

[0040] Other advantagees of the present invention are related to the use of synthetic material for manufacturing the closure that ensures constant quality and seal over time. Particularly, the use of

thermoplastic material associated with the presence of the groove 5 allows to obtain high performance in terms of tightness, thereby preventing the liquid or gas contained in the bottle from leaking out, and air from entering the bottle. This enables to maintain the pressure value within the bottle practically unchanged over time. Furthermore, due to the closure of synthetic material the stopper can be ejected in a controlled manner from the bottle following a simple manual pressure on the stopper, without using any corkscrew.

[0041] The teachings of the present invention can be not only applied to stoppers for bottles, but also to closures of a different type, such as demijohns, where the closure is provided to be partially inserted within the container mouth.