METHOD FOR MANUFACTURING STOPPERS AND STOPPER OBTAINED BY THE METHOD

Technical field

The present invention relates to a method for manufacturing stoppers for bottles, specifically stoppers partly made of plastic material.

The present invention also relates to the stopper obtained by means of this method. Background art

It is known that bottles of wine, brandy and the like are closed by using stoppers which, depending on production choices and requirements, are distinguished into cork, plastics or crown stoppers.

The most widely used stoppers made of cork and of plastics are inserted almost entirely in the neck of the bottle, from which they are extracted by means of suitable corkscrews of the type known as screw, spiral or worm.

Crown stoppers are instead applied to the upper rim of the neck of the bottle, with respect to which they remain fully external in order to be removed by means of so-called bottle openers, which are suitable for opening the bottle quickly and safely. In particular, the present invention is aimed at the first type of stopper mentioned, i.e., to stoppers whose extraction from the bottle occurs by means of screw-type corkscrews.

These known stoppers comprise a generally cylindrical contoured body which is entirely made of cork or plastics or of a suitable combination thereof.

Pure cork stoppers are the oldest and most widespread, and many are manufactured each year according to two main categories: one-piece cork stoppers, which are more valuable and expensive, and so-called agglomerated stoppers, which are composed of a granulated cork part, which is agglomerated by means of special polyurethane adhesives, and one

or more thin cork discs. Fully synthetic stoppers are formed instead by a mixture of petroleum-derived thermoplastic materials known as elastomers, which are aggregated by means of an injection-molding process.

Synthetic stoppers have good properties, since they do not crumble, do not form dust, cannot be attacked by molds or bacteria, offer an excellent and durable oxygen barrier, preserving over time the organoleptic characteristics of the liquid contained in the bottle, and are also absolutely immune to releases of any kind.

Moreover, synthetic stoppers are inserted in the neck of the bottle by means of conventional automatic corking machines used for cork stoppers and likewise they can be extracted with a conventional corkscrew.

With respect to cork stoppers, synthetic stoppers can in any case be customized by producing in the chosen color and by ink printing which bears for example the trademark of the manufacturer. For these reasons, synthetic stoppers are preferable to cork stoppers, as is by now widely acknowledged by many manufacturers and wine experts.

However, other experts in the field, such as wine shop owners or restaurateurs who also serve high-quality wines still have a rather diffident attitude toward synthetic stoppers, which they often refuse despite acknowledging their advantages.

This is due to the fact that plastic stoppers have a cost which is still scarcely competitive with respect to cork stoppers but most of all is due to a problem which is psychological, so to speak, and is linked to the end consumer, who associates the idea of quality wine with a bottle provided with the conventional cork stopper.

In view of all this, in order to achieve the typical advantages of synthetic stoppers without thereby compromising the image of wine quality perceived by a substantial fraction of experts in the field, stoppers have been proposed which, despite being mostly made of cork, also comprise parts

made of plasties.

Bottle stoppers which are composite, so to speak, are manufactured according to various embodiments, one of which has a contoured body which is substantially cylindrical and made of cork to which a laminar element of minimal thickness, made of plastic material, is applied at the top and bottom.

According to the current manufacturing method, the laminar elements are produced by injection molding performed in a mold which is separate and distinct from the one used for the contoured body, to which they are coupled by interposing connecting means, typically adhesive substances.

The main drawback observed in the background art is therefore that the method described above for manufacturing stoppers made partly of cork and partly of plastic material is exceedingly laborious and complex.

Another drawback of these stoppers is that in order to avoid causing diffidence in the experts in the field as regards the quality of the wine sealed in the bottles while trying in any case to introduce the exclusive advantages of synthetic stoppers, one ends by obtaining a spurious finished product which does not satisfy entirely the operators involved.

The aim of the present invention is to overcome the drawbacks of the background art cited above. Disclosure of the invention

The aim of the present invention is to provide a method for manufacturing stoppers which is simpler and less laborious to perform than known types of equivalent method. Within this aim, an object of the invention is to provide a method which leads to the manufacture of stoppers in a shorter time than in the background art.

Another object of the invention is to provide a stopper which, despite being apparently a cork stopper, which therefore retains a positive image in the eyes of experts in the field, has, with respect to the background art,

improved values of certain properties which arise from the fact that it has parts made of plastic material.

Another object of the invention is to provide a stopper made of composite material which, with respect to similar known stoppers, has a higher capacity to avoid producing dust, reduced transfer to the liquid contained in the bottle, a more effective barrier to oxygen, a lower level of crumbling and a higher ability to withstand the attack of molds or bacteria. This aim and these and other objects which will become better apparent hereinafter are achieved by a method for manufacturing stoppers according to claim 1, to which reference is made for the sake of brevity.

The aim of the present invention is also to provide a stopper whose essential characteristics are given in claim 12.

Other detail characteristics of the method and of the stopper obtained with the method according to the invention are given in the corresponding dependent claims.

Advantageously, the method according to the invention allows to simplify the operations required to produce a stopper made of composite material which is particularly suitable for closing bottles containing wine, brandy or liquor of high value. Also advantageously, the stopper according to the invention is obtained in a shorter time than known equivalent stoppers, with respect to which it has improved technical characteristics by virtue of the fact that it has a higher percentage of plastic material, which in the specific case is constituted by the core. This is not detrimental to the image of safety and confidence that has long been assigned, and for the time being is still well established among operators in the field, to the stopper made of cork, a material which in the invention still retains a significant role.

Brief description of the drawings Further characteristics and advantages of the invention will become

better apparent from the following detailed description of a preferred form of application and execution of the invention, given by way of non-limiting example with reference to the accompanying drawings, wherein:

Figure 1 is a longitudinal sectional view of a stopper according to the invention in the final step of the method according to the invention;

Figure 2 is a view of the stopper of Figure 1 after the manufacturing method has been completed. Ways of carrying out the invention

A stopper, preferably but not necessarily suitable to be applied to bottles of wine, brandy and the like, is shown in Figures 1 and 2, where it is generally designated by the reference numeral 1 , respectively during and at the end of the production process.

As can be seen, the stopper 1 comprises a contoured insert 2, which is intended to be associated with a container, such as for example a bottle, in order to close it, and two laminar elements 3, 4 made of plastic material, which are associated laterally on opposite sides with the contoured insert 2. According to the invention, the contoured insert 2 has a channel 5 which is connected to the outer surfaces 2a, 2b of the contoured insert 2, in which there is a core 6 made of plastic material. Other embodiments, not shown in the drawings that follow, may exist in which the stopper includes only one laminar element which remains visible or not once the stopper has been inserted in the neck of the bottle.

The channel 5 is a through channel, extends in a linear fashion along a longitudinal axis Y, and is preferably arranged in a central region 2c of the contoured insert 2 symmetrically with respect to the longitudinal axis Y.

According to further embodiments, not shown, the contoured insert may have more than one channel filled with a core made of plastic material, for example two channels, which are not visible from the outside.

The particularity of the stopper 1 according to the invention is also that the core 6 and the laminar elements 3, 4 are monolithic with each other.

This allows to say that the stopper 1 , as will become better apparent hereinafter, when describing the method with which the stopper 1 is produced, is simpler to manufacture than similar existing and currently commercially available stoppers. The plastic material of the core 6 and of the laminar elements 3, 4 is an elastomer or an appropriate mixture thereof, according to what is well- known to the person skilled in the art.

In this case, the core 6 and the laminar elements 3, 4 are made of the same synthetic material, but it is evident that in other embodiments of the stopper according to the invention, the plastic material of the laminar elements may differ from the plastic material that composes the core.

According to the preferred embodiment described here of the invention, the contoured insert 2 comprises an annular body 7 which surround the channel 5 and is substantially cylindrical. The annular body 7 is made of cork, which may be equally a single piece of cork or of the agglomerated type depending on its intended use.

There can also be other embodiments, not shown, in which the annular body is made of a material which is other than cork, for example synthetic material. Each of the laminar elements 3, 4 comprises a disk which has a beveled lateral rim and a diameter which is substantially equal to the diameter of the annular body 7.

Preferably but not exclusively, the laminar element 3, which when the stopper 1 is in the condition for application faces outward, has on the outer wall 3a a diametrical groove, not shown, which is adapted to accommodate a filament-like element or string which is appropriately wound onto the neck of the bottle in order to better fix the stopper 1 thereto.

The method that leads to the provision of the stopper 1 comprises the operations of preparing a mold S for producing the stopper 1 and of providing a pair of laminar elements 3, 4 made of plastic material.

According to the invention, the method includes also the following operations:

- providing the contoured insert 2 which has the channel 5 connected to the outer surfaces 2a, 2b of the contoured insert 2; - arranging the contoured insert 2 inside the mold S;

- molding the core 6 by injecting plastic material into the channel 5;

- associating the laminar elements 3, 4 laterally with respect to the contoured insert 2.

The operation of associating the laminar elements 3, 4 with the contoured insert 2 occurs within the mold S by spontaneous adhesion of the laminar elements 3, 4 to the contoured insert 2, therefore without using connecting means, for example adhesive substances, as instead occurs in known systems.

A first simplification is thus obtained, with respect to the background art, of the production method of the stoppers according to the invention.

The operation for manufacturing the laminar elements 3, 4 consists of an operation for injection-molding plastic material onto the outer surfaces 2a, 2b of the contoured insert 2 inside the mold S.

Advantageously, the operation for injection-molding the laminar elements 3, 4 and the operation for injection-molding the core 6 belong to a single injection-molding operation, so that the core 6 and the laminar elements 3, 4 are monolithic with respect to each other.

This is a further simplification of the method for manufacturing composite stoppers, especially for bottles, with respect to the current background art.

The operation for injection-molding the laminar elements 3, 4 is performed at a slot, not shown, which is formed between the inner wall Si of the mold S and each of the outer surfaces 2a, 2b of the contoured insert 2.

In greater detail,- the upper slot is formed between the outer surface 2a and by the assembly of the inner wall S; of the mold S and by the lower rim

of an injection lid N.

Likewise, the lower slot is formed between the outer surface 2b of the contoured insert 2 and by the assembly of the inner wall S, of the mold S and of the upper rim of an extraction element E. In order to provide the diametrical slot, the mold S has a central element which protrudes toward the inside of said upper slot and in which the injection-molding of the laminar element 3 occurs.

According to further embodiments of the invention, the operation for injection-molding the laminar elements can be performed at a pair of recesses which are formed on the outer surfaces of the contoured insert.

It is evident that if a single laminar element to be coupled to the contoured insert is provided, the injection-molding operation is performed, depending on design choices, either directly on just one of the outer surfaces of the contoured insert or in a single recess which is formed in one of said outer surfaces.

The mold S comprises two mold parts S ₁ , S ₂ which are mutually opposite and face each other, and between which a seat is formed which accommodates the contoured insert 2.

In the preferred embodiment being described, the mold parts S ₁ , S ₂ are mutually separated and rigidly coupled to each other by means of the injection lid N.

It is understood that in other embodiments, not shown, the two mold parts may be formed monolithically with each other.

Each of the mold parts S ₁ , S ₂ has a recess R, which is formed on an inner wall P; of each of them, and with respect to which one of the lateral surfaces 2d, 2e of the contoured insert 2 is shaped complementarily.

The recess R has a substantially U-shaped profile in transverse cross- section.

On the basis of what has been described above, it is therefore understood that the method for providing stoppers for bottles according to

the invention and the stopper obtained thereby achieve the intended aim and objects and provide the advantages mentioned earlier.

In particular, the method for providing stoppers according to the invention is feasible in a shorter time than the background art. Further, the stopper that is obtained has improved characteristics with respect to similar stoppers of a known type, formed by parts made of cork and parts made of plastic material, since the latter is present in a higher percentage.

As mentioned, this entails considerable benefits for the stopper, such as for example:

- a reduced level of crumbling and a reduced production of dust during its manufacture;

- greater resistance to molds and bacteria;

- a more effective oxygen barrier; - reduced releases to the liquid contained in the bottle to which the stopper is applied.

During production, changes in application can be made to the method according to the invention for manufacturing stoppers which consist for example of an injection-molding of different plastic materials for the core and for one or more laminar elements.

In this case, the injection molding of the mutually different plastic materials occurs in a closely spaced sequence within the mold S: thus, for example, in the case of the two laminar elements 3, 4 described above, the injection molding of the lower laminar element 4 is performed, followed by the injection molding of the core 6 made of another synthetic material and then by the injection molding of the upper laminar element 3.

Finally, it is evident that numerous other variations can be made to the method and to the stopper according to the invention, without thereby abandoning the principles of novelty that are inherent in the appended claims, and it is likewise evident that in the practical embodiment of the

invention the materials, shapes and dimensions of the illustrated details may be any according to requirements and may be replaced with other technically equivalent ones.

The disclosures in Italian Patent Application No. VI2006A000154, from which this application claims priority, are incorporated herein by reference.