MXPA99010375A - Sealing metal cap with plastic insert - Google Patents

Abstract

The invention concersn a capsule (1,100) comprising a metal cap (2), a plastic insert (4) positioned inside said metal cap and integral with it by fixing means. The invention is characterised in that said fixing means consist of a layer (3) adhering to said metal cap (2) extending over all or part of said metal cap opposite said insert, and said layer (3) comprises said plastic, material in divided state, and it is heat-sealed with said insert (4).

Description

METAL CAPSULE OF PLASTIC WITH ELEMENT OF PLASTIC INSERTION FIELD OF THE INVENTION The invention relates to the field of metal capping capsules and, more particularly, to the field of capping capsules with a threaded plastic insert adapted to the screw-in glass rings. These capsules are used mainly for the clogging of containers, bottles and bottles containing liquors and spirits.

ANTECEDENTS OF THE TECHNIQUE Capping capsules with plastic insert, typically SUPALUXE® capsules marketed by the applicant, consist of a metal capsule, a plastic insert and possibly a seal if the insert element itself does not have a sealing function. The assembly of the plastic insertion element with the capsule is done by joining REF .: 32084 pressure of the insert element in the metal capsule. Figure 2 represents a capsule of the prior art with an added joint. As we can see in this figure, the greatest interest of this type of capsule lies in the fact that the external metal capsule has no filleting mark, which contributes to the aesthetic quality of the capsule and the container, typically a bottle or a bottle. In addition, the threaded plastic insert allows a large number of corking-uncorking cycles to be carried out, since it is screwed-screwdriver without geometrical modification of the capsule, which is necessary when dealing with liqueurs and spirits.

POSED PROBLEM The problem posed mainly by these capsules is mainly linked to the unscrewing of the capsule, in particular when the contents of the container contain sugar or any other product capable of crystallizing. In effect, the crystallization of the sugar contained in the bottled liquid can block the plastic insert in the glass ring, so that when the capsule is unscrewed, the metal capsule slides in the insert element / the cohesion between the glass ring and the insertion element to the cohesion between the metal capsule and the insert element, which prevents opening the bottle. To solve this problem, an attempt has been made to increase the limiting torque from which the rotating detachment of the metal capsule and the insertion element takes place. For this, the applicant has tried to reduce the tightening torque between the insertion element and the metal capsule, increase the roughness of the surfaces in contact, modify the nature of the insertion element, introduce a layer of adhesive or hot-elt between the metal capsule and the insertion element. These measures did not solve the problem.

DESCRIPTION OF THE INVENTION According to the invention, the stopper capsule with plastic insert for plugging screw containers comprises a metal capsule consisting of a head and a skirt, an insert in plastic material positioned within said metal capsule and attached to this same capsule by a fixing means, characterized in that said fixing means is formed by a layer adhering to said metal capsule extending in all or part of said metal capsule with respect to said insert element, because said layer comprises said material plastic when separated and because it is hot sealed with said insert element. Preferably, said layer extends over the entire part of said metal capsule with respect to said insert element. In fact, if said layer covers the entire internal surface of said metal capsule, problems may arise at the time of capsulation due to the lack of slippage of the final capsule. The solution found by the applicant allows a considerable increase in the sliding torque of the insert element in the metal capsule, typically multiply by 6. This pair, measured according to the NF H 35103 standard, goes from less than 17 lbs.inch (or 1.9 Nm) to more than 100 lbs.inch (that is, 11.3 N.m). With the means of the invention, the problem raised is completely solved. In fact, with all the capsules made according to the invention, no uncoupling has ever been observed between the insert and the metal capsule, even with highly crystallized sugar deposits.

DESCRIPTION OF THE FIGURES Figure 1 represents, in axial semi-section, a capsule (1) according to the invention which. It comprises a metal capsule (2) and an insert (4) joined by a layer (3). A seal (10) is present at the bottom of the insert (4). The skirt of the capsule (1) has a circular line of weakening formed by a succession of bridges (11). Figure 2, analogous to the representation of Figure 1, is a representation of a capsule (1000) according to the state of the art. Figures 3, 4 and 5a to 5e illustrate the different steps of a capsule manufacturing mode according to the invention.

Figure 3 shows in section, the "internal" varnishing of a strip of metal (7) in a coil with a varnisher comprising a varnishing roller (71) bathed in a liquid varnish container (72), to form a band of coated metal (8), the means of drying or firing the varnish having not been illustrated in this figure. Figure 4, analogous to Figure 3, illustrates the next step during which the localized application or "spot-coating" of said adherent layer is performed on the coated metal band (8). For this, a screen printing technique with a cylindrical grid (81) with open or closed cells can be used according to whether the liquid mixture (82) has to be applied or not on the coated metal band (8) to form after drying or baking a band (9) coated with said layer (3). It is also possible to use an offset method to apply a varnish layer to certain predetermined parts of the strip (8). As in Figure 3, the drying or cooking means of the liquid mixture (82) are not shown. Figure 5a illustrates, in section and seen from above, the circular flake (900) cut in the band ('9) obtained in figure 4, for its shaping, typically by embossing and drawing. Figure 5b represents, in axial section, the metal capsule (2) obtained by shaping the codend (900). Figure 5d illustrates schematically, in section, the assembly of the metal capsule of figure 5b and an insertion element (4), by hot sealing by means of a punch assembly (5) and a thermal matrix (6). ) at a temperature T and applying a pressure P for a time t. Figure 5e schematically illustrates, in section, the final capsule (1) made according to the invention. Figure 6 illustrates schematically and in section a second embodiment of the invention in which the band (90), which corresponds to the band (9) of the previous embodiment, comprises at the same time a layer (3) on one side of the band and one layer (30) on the other side of the band. In this case, the metal band (7) is also coated with an external coating (210), analogous to the internal coating (21). Figures 7 and 8 illustrate in section the capsules (100) obtained from the band (90). These capsules (100) comprise a cap of plastic material identical to that contained in said hot-sealed layer (30) thanks to said outer layer (30). Figures 7 and 8c illustrate some non-restrictive forms of these caps (12), with round head (figure 12) or flat (figures 8 to 8c), and in this case circular section (figure 8a), square (figure 8b) , hexagonal (figure 8c).

DETAILED DESCRIPTION OF THE INVENTION According to the invention, said layer (3) joining said insertion element (4) and said metal capsule (2) comprises a sufficient quantity of said plastic material in the separate state to guarantee by hot sealing a high adhesion that allows to respond to the problem raised Thus, when said insert is in polyolefin, preferably PE or PP, said layer comprises at least 3% by weight of said polyolefin. Typically, said adherent layer (3) is a thermosetting varnish comprising between 5 and 30% by weight of said polyolefin, for adhering simultaneously to said insert (4) and said metal capsule (2).

Preferably, said thermosetting varnish is an epoxy varnish. In this case, said metal capsule (2) comprises an internal coating (21) formed by a layer of epoxy varnish. According to the invention, said metal capsule (2) is aluminum, iron, tin or a multilayer material comprising a metallic inner layer. According to one embodiment of the invention, the stopper capsule (1) can comprise an added seal (10), as illustrated in figure 1. This gasket, whose function is known, is kept at the bottom of the insert element typically by a circular throat. According to another modality that is not represented in the figures, the plugging capsule (1) may comprise, instead of a gasket (10), a self-sealing insert ensuring by itself the required tightness. Furthermore, the capsule (1) according to the invention can comprise means intended to facilitate the first opening, and preferably at least one weakening line, or several weakening lines forming a tear-off tongue.

Figure 1 represents a capsule with a single line of weakness formed by a succession of bridges (11) that break at the time of the first opening. Another object of the invention resides in the method of manufacturing capsules (1) according to the invention. In this method: a) metal band or foil (7) is provided for forming according to the known method said metal capsule, b) preferably, it is formed in the entire "internal" face of said band or sheet, according to with the known method, a varnish layer (21), intended to facilitate the shaping of said metal strip or sheet, inter alia by embossing and drawing, (c) subsequently, said layer is formed by localized application or "spot-coating". adherent (3) in the part of said "internal" face with respect to part or all of said insertion element, d) the metal sheet or band (9) obtained in c) is formed to obtain, according to the known method, said metal capsule (2) coated internally and locally with said adherent layer (3), e) said insert element is positioned (4) and said insert element (4) and said metal capsule are assembled by thermoforming. (2) obtained in d), so that said layer (3) adheres to said insertion element (4). Figures 3 to 5e illustrate schematically this procedure. According to another embodiment of the invention illustrated in figures 6, 7 and 8 to 8c, a layer (30) similar to said layer (3) can also be formed outside said metal capsule. For that, a band (90) is prepared, according to figure 6 and corresponding to the band (9) of the previous modality, which comprises at the same time a layer (3) on one side of the band and a layer (30) on the other side of the band. Preferably, the cap (12) and the insertion element (4) are simultaneously fixed to said metal capsule coated with said layers (3) and (30), heating by induction the part of said metal capsule coated with said layers (3) and (30).

Capsules (100), illustrated as an example in figures 7 and 8 to 8c, are obtained in this way.

EXAMPLE OF REALIZATION Capsules (1) according to figure 1 have been manufactured with a height X equivalent to 60 mm, the other dimensions in (mm) of capsule being shown in figure 1. For this purpose, an aluminum alloy band has been used. Series 3000 (denomination according to the Aluminum Association), 210 μm thick, whose two sides have been varnished with an epoxy varnish applied at 2.5 g / m2. In the varnished aluminum strip (8) thus obtained, a liquid varnish (82) designed to form said adherent layer (3) adhering to the metal capsule (2) has been applied by "spot-coating", as illustrated in FIG. 4. ), to form a band (9) coated locally and at predetermined points with a layer (3) of 8 g / m2 in dry matter. This varnish had the following composition: 87 parts of commercial epoxy varnish with 31% dry extract, 13 parts of PP dispersion from the trade (MORPRIME®) with 15% dry extract, ie a layer (3) which contains approximately 6.7% by weight of PP, stabilization aids more or less (% by weight of dry matter). The band thus coated has been dried at 180 ° C for 12 min. This band has fed a conventional shaping and drawing device, said device including cutting flakes (90) that feed the sausage and stretch machine. In this way, metal capsules (2) coated in part on the inside with said layer (3) have been achieved, as illustrated in Figure 5b. Insertion elements were provisioned PP, as illustrated in Figure 5c and they were joined to the metal capsules (2) by means of a device consisting of a punch (5) and a thermal matrix (6), as illustrated in Figure 5d. The temperature T of the matrix (6) was 350 ° C, the pressure P applied between punch and matrix was 120 daN and the time t of 0.15 s. Other conditions of T, P, t, are possible, but it is important to have a high productivity procedure and also choose a torque Tt to achieve a sufficient softening of the PP of said layer (3) so that the PP of the layer (3) can adhere to said insertion element (4), without there being any risk of deterioration of said insertion element (4), among other things due to an excessive generation of calories. In addition, a weakening line has been made with bridges (11) and a gasket (10) has been inserted. The capsules obtained according to the invention have been tested in bottles containing liquors with a lot of sugar. In all cases, the insertion element (4) has remained attached to the metal capsule (2), in reverse to what could be observed with the capsules of the prior art. Other tests have been carried out in which the layer (3) was applied only partially with respect to the insertion element: with respect to the head of the insertion element, with respect to the skirt of the insertion element. The mechanical decohesion tests have shown, as expected, that the limiting torque generated by the decohesion between the insertion element (4) and the capsule (2) varies according to the extension and the position of the layer (3), either to the entire insertion element, either with respect to the skirt (43) of the insertion element, or with respect to the head (42) of the insertion element. Depending on the nature of the bottled liquors, it is possible to choose and limit the extension of the layer (3) to what is necessary to solve the problem posed. Furthermore, the capsules according to the invention do not represent a significant extra cost compared with the capsules of the state of the art: the cost of the materials forming the layer (3) is cheap given the reduced thickness of the layer (3) and of its limited surface, on the other hand the varnishing operation is included in the standard manufacturing process. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (12)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Corking capsule with plastic insert for plugging threaded containers, comprising a metal capsule formed by a head and a skirt, a threaded insert element of plastic material positioned within the metal capsule and attached thereto by a means of fixation, characterized in that the fixing means is composed of a layer that adheres to the metal capsule and extends in all or part of the metal capsule with respect to an insert, because the layer comprises a plastic material in a separate state and because it is hot sealed with the insert element.

2. Capsule according to claim 1, characterized in that the layer extends over the entire metal capsule with respect to an insert element.

3. Capsule according to any of claims 1 to 2, characterized in that the insert is made of polyolefin, preferably in PE or PP, and in that the layer comprises at least 3% by weight of the polyolefin.

4. Capsule according to claim 3, characterized in that the layer is a thermosetting varnish comprising between 5 and 30% by weight of the polyolefin.

5. Capsule according to claim 4, characterized in that the varnish is an epoxy varnish.

6. Capsule according to claim 5, characterized in that the metal capsule comprises an internal coating formed by a layer of epoxy varnish.

7. Capsule according to any of claims 1 to 6, characterized in that the metal capsule is aluminum, iron, tin or multilayer material with a metallic inner layer.

8. Capsule according to claim 7, characterized in that it comprises an added seal.

9. Capsule according to claim 7, characterized in that the insert includes a self-sealing system.

10. Capsule according to any of claims 1 to 9, characterized in that it includes means intended to facilitate the first opening and preferably at least one weakening line.

11. Capsule according to any of claims 1 to 10, characterized in that it comprises an external cap fixed to a metal capsule thanks to an external layer analogous to a layer.

12. Process for manufacturing capsules, for capping with a plastic insert for plugging screw containers, comprising a metal capsule formed by a head and a skirt, a threaded insert element of plastic material positioned inside the metal capsule and attached to it by means of fixation, characterized in that the fixing means is composed of a layer that adheres to a metal capsule and extends in all or part of the metal capsule with respect to an insert, because the layer comprises a plastic material to the separated state and because it is thermowelded to an insertion element, procedure where: a) metal band or foil is provided for forming according to the known method the metal capsule, b) preferably, it is formed in the whole of the "internal" face of the band or sheet, according to the known method, a coating of varnish, intended To facilitate the shaping of the metal strip or sheet, inter alia, by embossing and drawing, c) then the adherent layer is formed by localized application or "spot-coating" on the part of the "internal" face intended to be facing in front of part or all of the insertion element, d) the metal sheet or band obtained in c) is formed to obtain, according to the known method, the metal capsule coated internally and locally with the adherent layer, e) the element is positioned of insertion and the insertion element and the metal capsule obtained in d) is gathered by thermoforming, so that the layer adheres to the insertion element.