MXPA06005154A - Method for the production of capsules with a heat-shrinkable skirt and capsules obtained according to said method - Google Patents

Abstract

The method comprises a) an extrusion stage wherein a extruded tube made of a thermoplastic material (20) is formed by extrusion with the aid of an extrusion die having a diameter D0, a slit width E0 and a section S0;b) a stage wherein the extruded tube (20) is radially expanded in order to form a radially expanded tube (23) having a diameter D2, a thickness E2 and corresponding section of area S1;c) a truncating stage wherein the expanded tube (23) is broken down into tube portions (24);d) a stage in which the tube portions (24) are formed in such a way that a heat-shrinkable cap or capsule is obtained (1) and in which an axial drawing stage is incorporated, between extrusion stage a) and expansion stage b), at the output of the extrusion die (31), in order to obtain an axially drawn tube (22) having a diameter D1 which is typically smaller than D0 and D2, and a thickness El which is typically lower than E0, such that S0/S1 typically ranges between 2 and 10. The advantages of the invention are as follows:it is possible to obtain capsules (1, lb, lc) or caps (la) which are economic, easily heat-shrinkable and which have a stable axial dimension, thereby avoiding any axial distortion, i.e. any axial distortion of said impression (13).

Description

PROCEDURE FOR MANUFACTURE OF CAPSULES WITH THERMORRETRACTAL SKIRT and CAPSULES OBTAINED WITH THE PROCEDURE FIELD OF THE INVENTION The invention relates to the field of capsules for clogging containers or bottles or to over-packing containers or bottles previously covered with a cap, a cover or any other means of capping. More particularly, the invention relates to the domain of heat-shrinkable capsules, that is to say capsules formed by a thermoplastic material which, during capsulation, are narrowed on the neck by the input of thermal energy, contrary to the metal capsules whose skirt is overlapped. it is crimped under the glass ring of the neck during capsulation. More specifically, the invention relates to a new method of manufacturing capsules with a terre-retractable skirt, overcapping capsules and, optionally, capsules with a heat-shrinkable skirt.

BACKGROUND OF THE INVENTION Heat-shrinkable capsules (TR in abbreviation) have been known for a long time. So, the FR patent No. 805,771 describes the manufacture of a PVC-based capsule formed by extrusion of a PVC-based tube and, after REF. : 172687 an eventual elongation, by expansion of the tube at the exit of the extruder, cooling and cutting into pieces of cylindrical tubes, which forms a retractable sleeve in the neck of a bottle. GB 1,015,713 also discloses a method of manufacturing capsules TR in which a tube, made of PVC or PS material and made heat-shrinkable by expansion, is crushed and heat-sealed transversely at one end in order to seal it, and then it is chopped to form a crushed capsule which, after separation, forms a capsule with a welded head that can be placed and thermally retracted into a bottle neck. The patent FR 1,372,805 also describes a method of manufacturing heat-shrink tubular sleeves that can be used to seal bottle capsules, in which a tube of two PEs (a relatively fusible and a relatively non-fusible) is co-extruded, which is then cross-linked by irradiation and it expands. Patent FR 1,424,731 also describes a method of manufacturing capsules TR in which a piece of shrinkable tube is retracted in a gauge provided in its upper part of a disc to form a heat-shrinkable capsule whose head is formed by the corresponding disc.

Patent FR 1,441,623 describes a method of manufacturing heat-shrinkable sheath by extrusion of PE, followed by cross-linking by irradiation and then expansion of the sheath. The patent FR 2,115,137 also describes a method of manufacturing capsules TR in which a blank is cut in a sheet of heat-shrinkable plastic, and in which a rolled capsule TR is formed by welding the side edges by coating sensibly axial. You can also stick a capsule head. This capsule can be combined with a bottle cap. The patent FR 2,201,957 also describes a method of manufacturing capsules TR in which a sleeve, formed from an extruded tube of heat-shrinkable and expanded material, is retracted in a frustoconical mandrel at the head of which was placed a lid of thermoformable material but not heat shrink. The patent FR 2,219,080 also describes a capsule TR formed by thermal retraction in a mandrel of a tubular part of PVC or PS, the end forming the head of the capsule is obtained by tamping and compressing a piece of length of the corresponding part tubular. The patent US 5,118,460 describes a method of manufacturing TR capsules by molding. Similarly, patent FR 2,708,513 describes a method of manufacturing capsules TR in which a preform is first formed by molding and then expanded. French patent FR 2,817,193 is also known in the name of the applicant which describes a method of manufacturing capsules TR using an irradiation medium.

PROBLEMS RAISED Capsules or caps with heat shrinking skirt already known, and in particular those described in the French patent FR 2,817,193, present several drawbacks: on the one hand, they resort to an irradiation device, which presents an investment cost to the time an operating cost. In addition, despite the fact that the user does not technically run any risk with the capsules thus manufactured, it is clear that associating "irradiation" with a container means of a beverage can cause some reluctance on the part of the users, even when not they are justified, - on the other hand, it was observed that the capsules, typically printed and once thermally retracted in the necks, posed problems of axial dimensional stability, with deformations that altered the impression, - others, the productivity per hour of the procedure turned out to be too low, - finally, the known method does not have sufficient flexibility to meet the diversity of the new needs, both in terms of the sensory properties of the capsules, such as the textures, the touch or also the loudness during the use or any contact, in order to obtain in particular sensory properties similar to those of the as various capsules considered in the market as the high range. On the other hand, all these capsules have to present an ease of opening the capsule, although the capsule is not provided with easy opening means (easy to open), even if it is cut with a knife from the top of the capsule, or by "detachment" with a knife from the capsule from its bottom, according to the tradition of each country and without risking hurt yourself BRIEF DESCRIPTION OF THE INVENTION According to the invention, the method of capsules or caps with heat-shrinkable skirt comprises: a) an extrusion step in which an extruded tube of thermoplastic material is formed by extrusion, with the help of an orifice fed by a Extruder that works at the temperature TO chosen according to the softening or melting temperature Tf of the corresponding thermoplastic material, the corresponding hole has a diameter DO, a slot width or thickness EO and a corresponding section with an area SO, b) a stage of radial expansion of the corresponding extruded tube, to form a radially expanded tube with a diameter D2, a thickness E2 and a corresponding section with an area S2, thanks to a radial expansion device, c) a step of chopping, in which the corresponding expanded tube is cut into pieces of tube of appropriate length, the corresponding radially expanded tube an axial pulling means is pulled, d) a step of forming the tube pieces, wherein each piece of tube is placed in a typically frustoconical forming mandrel and formed by thermal shrinkage to form a blank. thermally retracted capsule, furthermore, a head is typically assembled to the corresponding raw piece or formed from the corresponding raw piece, in order to obtain a capsule or a heat-shrinkable cap provided with a head and a skirt, and typically suitable for receiving an impression, and is characterized in that an axial stretching step of the corresponding extruded tube is added, at the exit of the extruder orifice, between the corresponding extrusion stage a) and the corresponding expansion stage b), In order to obtain an axially stretched tube with a diameter DI typically smaller than the diameter DO and the diameter D2, a thickness typically lower than the EO spesor, and a corresponding section with an SI area, so that SO / SI is typically included between 2 and 10, the corresponding extrusion, axial stretching, radial expansion and chopping stages are carried out by continuous displacement, with the in order to obtain capsules or caps which are both economical, easy to retract thermally and with a stable axial measurement to avoid any axial distortion, in particular any axial distortion of the corresponding impression. Particularly for reasons of productivity and to obtain a high extruder flow rate, it is advantageous to obtain DO >; GAVE. In addition, it is also advantageous to obtain relatively small DI to obtain a relatively high D2 / D1 ratio in order to obtain a thermally retractable capsule. However, nothing prevents having DO and DI substantially the same. The SO / SI ratio is a measure of the axial stretch, the material flow rate equal to S.V remains constant, V is the linear velocity, so that, when S decreases, the velocity V of the tube increases proportionally. On the other hand, in case of pure radial expansion, the diameter D is the only one that increases, the area S and the velocity V are not modified.

The instantaneous velocity V could be measured at different points of the tube of thermoplastic material, for example by projection in the extruded tube just outside the extruder, of color marks spaced regularly from ≤10 according to the axial direction, so that the Measured with the aid of a stroboscopic device of? li and? l2, it is possible to calculate VI and V2, knowing VO, the speed of the flow of matter or of the extruded tube at the exit of the extruder. This procedure allows solving the problems raised. In effect, on the one hand, this method does not use any irradiation device, such that the drawback of the previous procedure put to point by the applicant is eliminated, a disadvantage in particular linked to the negative image before the general public of all types of irradiation. On the other hand, it was observed that the capsules or caps obtained with the method of the invention, and printed, were easy to retract thermally and did not present, after retraction in the neck, axial distortion of the printed pattern. Finally, according to the invention, tests of the process were carried out with a large number of different materials and combinations of different thermoplastic materials, both in the form of monolayer extruded material and in the form of bi-or tri-layer coextruded material, so that it is possible to obtain a wide variety of capsules or caps different in terms of touch, appearance, elasticity, sound with respect to contact with a more or less matt or crystalline sound, flexibility and ease of cutting with a knife, etc. Thus, the method according to the invention allows, in particular, but always to reproduce the sensory impressions of each type of capsule or caps, at least approaching these sensory sensations more often, even enriching them with new sensations, so that it becomes possible propose "custom-made" products, at the request of the clients.

BRIEF DESCRIPTION OF THE FIGURES All figures are relative to the invention. Figures a to 3d are relative to the manufacture of the pieces of tubes 24. In figure 1, the main equipment of the line of manufacture 3 of pieces of tubes 24 are schematically represented. Figure Ib illustrates, in parallel to the figure, the manufacturing process and the manufacturing line 3 in operation. Figure 1c corresponds to a partial view illustrating a variant of the method and the manufacturing line of Figure Ib. In this variant, a ring 322 is interposed between the hole 31 of the extruder 30 and the radial expansion device 34. In this figure, this ring is a calibration ring 33 which calibrates the axially stretched tube 22 according to the diameter DI, and a cooling ring 322 provided with a water circulation 321. Figure 2 is a partial view of the radial expansion device 34, seen in section in axial direction 25 common to the extruded tubes 21, axially stretched 22 and expanded 23. In this figure, the corresponding axially stretched tube 23 arrives on the left and is observed from the left to the right: an input ring 340 with a diameter DI, which can serve as a calibration ring, an expansion zone 341 provided with holes 3410 , and an inner wall 342 with a diameter D2, set formed by cooperation of an internal tubular metal part 345 with an outer chamber 348 provided with vacuum taps 349. The right part of The radial expansion device 34 comprises an auxiliary cooling means 347, typically formed by a spray or circulation of cold water.

Figure 3a illustrates, in the case in which the axial stretching step extends from the outlet of the hole 31 to the entrance of the corresponding radial expansion device 34, the evolutions of the corresponding thermoplastic material 20 during the different phases of manufacture of the pieces of tubes 24, without using the equipment of the manufacturing line 3, and from the left to the right: - the extrusion phase that produces, at the exit of the corresponding hole 31, the corresponding extruded tube 21 having a diameter DO, as shown in section in Figure 3b shows the axial stretching phase leading to the axially stretched tube 22 with a diameter DI, as shown in section in figure 3c, the radial expansion phase leading to the radially expanded tube 23 with a diameter D2, as shown in FIG. It represents in section in figure 3d. In figure 3a, the thicknesses E and the linear velocities V of the plastic material according to the corresponding axial direction were indicated. Figures 4a to 7 illustrate the manufacture of capsules 1, Ib, lc or caps Ib from the pieces of tubes 24 manufactured as illustrated in the figures a 3d. Figures 4a to 4d are sectional views according to the corresponding axial direction 10, illustrating the different phases of a method according to the invention. In this embodiment, the corresponding piece of tube 24 is a "long" piece 241 comprising a lower part 242 intended to form the skirt 12 and which thus corresponds substantially to the height H of the capsule or the cap, and an upper part 243 intended to form the head 11. Figure 4a represents the initial position of the corresponding long piece 241 with respect to the forming mandrel 40 and its head 400. Figure 4b represents the blank 26, 27 after the thermal retraction of the corresponding long piece 241, obtained thanks to a heat input Q, blank that comprises an upper part 270 located above the head 400 'of the mandrel 40. Figures 4c and 4d represent the formation of the head 11 by compression of the corresponding upper part 270 between the head 400 of the mandrel 40 and a die 42, with relative displacement with respect to the mandrel 40 in the axial direction 10. The final capsule 1, la, Ib, is rep- Figure 4e (upper left) in side view (the section view corresponds to the dotted line), which illustrates the printing of a capsule by means of a printing device 7 comprising a plurality of nozzles printing 70 projecting inks into the capsule 1, the, Ib, lc located on a rotating support (not shown) associated with a motor 72, typically step by step, each of the printing nozzles 70 is provided with a microvalve whose opening / closing it is controlled by a computer according to the coordinates of the considered point of the printed pattern 130 to be reproduced, ie the height H and the angular coordinate O, motif stored in the computer 71, as represented on the computer screen 71. The plurality of nozzles 70 forms a head or ramp 73 usually fixed with respect to the axis of rotation 10, the computer 71 synchronizes the rotation of the capsule and the opening / closing d and the nozzles 70. The nozzles 70 can be grouped by three, each of the three guarantees the projection of a primary color (yellow, magenta and cyan} , two complementary nozzles can project a white ink and a black ink, in order to reproduce a very important number of shades per trichromy. Depending on the desired fineness, a more or less significant density of nozzles per mm is chosen. Above left, figure 4f represents the printed capsule 1, obtained as illustrated in figure 4e. Above right, it represents the same capsule, overcap capsule lc, located in a neck 8 capped with a cap 80. Below, it represents the overcap capsule 9 thermally retracted in the corresponding neck 8 by means of a contribution of heat Q. Figures 5a to 5d illustrate another embodiment of capsule 1 according to the invention in which the corresponding capsule comprises an insert 5 'comprising a head 50 and a skirt 51. As illustrated in figure 5a, analogous to Figure 4a, the insert 5 'is located on the head 400 of the mandrel 40. As illustrated in Figure 5b, analogous to Figure 4b, the piece of tube 24 is thermally retracted into the skirt 51 of the insert and thus, or optionally thanks to an adhesive layer, the retracted skirt piece becomes integral with the insert 5 ', in order to form the capsule 1, Ib also shown in section in figure 5c. Figure 5d is a side view of the stopper capsule Ib after having provided the skirt 12 with an easy-opening means 14 comprising two typically parallel weakening lines 140, lines delimiting an opening tab 141 that is released when opening the container for the first time pulling on its gripping end 142. Figures 5e and 5f are relative to the case in which the capsule 1 is a cap for champagne bottle neck 8 'capped with a cap provided with a head 80'. . Fig. 5e is a sectional view, while Fig. 5f is a side view analogous to Fig. 5d, the cap comprises an easy opening means 14 comprising two lines of weakness 140 spaced apart. Figures 6a to 7 illustrate various embodiments of the method and the corresponding device 4 for forming the tube pieces 24. Typically, the device 4 comprises an endless chain conveyor 41, with a vertical or horizontal axis of rotation 410, mandrels, which typically comprises 4 to 8 with 4 to 8 corresponding angular positions. In figure 6a, an endless chain conveyor 4 was represented, comprising in continuous line 4 mandrels and 4 angular positions: - in the right position, the loading of the long pieces of tube 24, 241, - is carried out in the high position , the thermal retraction is carried out by supplying heat Q, - in the left position, the molding of the head 11 is effected by compression of the upper part 270 between the matrix 42 and the head 400 of the mandrel 40, - in the low position , the capsule 1 is ejected. Figure 6b is a partial representation of the figure 6a to illustrate a variant in which an auxiliary part 6 is inserted in the matrix 42 in order to heat-seal it in the head 11 formed during compression in the corresponding left position. Figure 7 is analogous to Figure 6a and illustrates a variant in which, in the so-called right position, short pieces of tube 24, 240 are loaded, and in the so-called left position, tablets 5 are supplied in the corresponding matrix 42, pads formed from a web material 52. Figures 8a to 8d, analogous to Figures 4a to 4d, relate to a variant of the process described in Figures 5a to 5d to manufacture capsules Ib for capping. In the case of figures 8a to 8d, the head 50 of the threaded insert 5 'is completely covered by the layer of thermoplastic material formed by compression of the upper part 243 of the long piece of pipe 24, 241. Figure 8e is a view in section of the final capsule Ib. Figures 9a to 9d are schematic views in axial section of the axially stretched tube 22, shown between the outlet of the corresponding hole 31 and the corresponding radial expansion device 34. In Figure 9a, the corresponding axially stretched tube 22 is shown without a device cooling 32, with a diameter D that decreases substantially according to a part of hyperbole according to the axial distance, the corresponding radial expansion device 34 is movable with respect to the corresponding hole 31 in order to adjust the distance 1 between the corresponding hole 31 and the radial expansion device 34, so that the diameter of the axially drawn tube corresponds to the inlet diameter DI of the radial expansion device 34. In FIGS. 9b to 9d, a cooling means or device 32 is interposed between the hole 31 and the radial expansion device 34, the cooling device 32 fixes the diameter of the tube according to the value of the diameter D which corresponds substantially to the axial distance LO in the hyperbole part of figure 9a. In figure 9b, the cooling device 32 is located at the distance LO from the corresponding hole, or at the distance L-LO from the corresponding radial expansion device 34, so that the diameter D corresponds to the diameter DI of the corresponding device of radial expansion 34. Figure 9c represents the case in which the cooling device 32 is located at an axial distance > LO, which causes D < GAVE . The axially stretched tube 22 does not stick against the entrance ring or crown of the corresponding radial expansion device 34, hence a problem of radial expansion arises. Figure 9d represents the case in which the cooling device 32 is located at an axial distance < LO, which causes D > GAVE . The axially stretched tube 22 has a diameter significantly greater than that of the ring 340 or annular chamber 340 'at the entrance of the radial expansion device 34, hence a problem of high axial stress that has to be exerted on the corresponding axially stretched tube 22 , the corresponding ring 340 or the corresponding annular chamber 340 'thus form a constriction for the axially stretched tube 22, an increase in the axial tensile stress can particularly cause undesirable axial stretching during the radial expansion stage b). Figures 10a to lOd are analogous to Figures 3a to 3d and illustrate the case in which the axial stretch stage is delimited, at the rear, with a cooling zone in which a cooling means 32 fixes the diameter of the axially stretched tube 22 to a diameter DI. Figure 11, analogous to Figure 2, illustrates the case in which the corresponding radial expansion device 34 comprises as an input ring 340 an annular chamber 340 'forming a suction chamber 3400 provided with a perforated tubular portion 3401, typically removable with respect to the radial expansion device 24, which makes it possible to control the temperature of the corresponding inlet ring in order to heat or cool the axially stretched tube 22 to the inlet of the radial expansion device 34, as well as a control of the pressure in the suction chamber, in order to be able to evaluate whether this suction chamber 3400 sucks the axially drawn tube, sticking it against the perforated tubular piece 3401.

Figures 12a and 12b are partial views relative to the axial traction means 35 formed by two matrix wheels 350 located opposite. Figure 12a is a sectional view in a vertical plane perpendicular to the corresponding axial direction 25. Figure 12b is a sectional view in a vertical plane containing the axial direction 25.

DETAILED DESCRIPTION OF THE INVENTION According to the invention, the axial stretching step can be delimited, at the rear, with a cooling zone in which a cooling means 32 lowers the temperature of the axially stretched tube 22 to a temperature TI , this temperature TI is chosen: a) high enough to be at least equal to the glass transition temperature Tg or to the melting temperature Tf of the corresponding thermoplastic material, in order to be able to develop the subsequent radial expansion stage , b) low enough to interrupt the axial stretch stage and thereby fix the diameter of the axially stretched tube 22 to a typically predetermined diameter DI. The corresponding temperature TI can be such that? T, equal to TO-Tl, goes from 30 ° C to 150 ° C and typically from 45 ° to 100 ° C. As illustrated in Fig. Ib or in Figs. 9b to 9d, the cooling means may comprise an exterior projection of air or water, typically annular 320, represented by a plurality of parallel arrows in Figs. Ib and 9b to 9d. As illustrated in Figure 1c, the cooling medium may comprise a ring 322 cooled with air or water. In this case, the corresponding ring can comprise a part with a diameter DI, in order to form a calibration ring 33 from which a tube with a diameter DI, typically axially stretched and cooled to the temperature TI, emerges. According to another variant of cooling medium (not illustrated in any figure), the cooling means may comprise a projection of air or water inside the corresponding axially drawn tube, typically thanks to a conduit passing through the corresponding hole. The temperature drop ΔT obtained in the cooling zone as well as the axial stretching cause an increase in the mechanical characteristics of the drawn tube 22, which is advantageous in a method in which a pull is exerted on the tube at the end of the tube. production line. However, since the radial expansion stage following the axial stretch stage involves a large deformation of the tube, deformation which implies a small rigidity of the stretched tube 22 at the entrance of the radial expansion device 34, this temperature drop? T has to be controlled and limited. Whichever cooling mode is used, the cooling medium, which is applied after the axial drawing step at the exit of the extruder at the length LO, tends to fix the diameter of the axially stretched tube, as illustrated in the figures 9a to 9d. Typically, the length LO corresponding to the axial stretch may be included between 0.2 m and 2 m. It can be noted that, throughout this length LO, many physical magnitudes vary and therefore have a gradient, which is the diameter D, the thickness E, or the velocity V of the tube. As illustrated in figures Ib, lc, 2 and 11, the radial expansion device 34, initially supplied with axially stretched tubes 22 at the temperature TI, can comprise a radial expansion chamber 344, first provided with an area of expansion 341 intended to pass the corresponding axially stretched tube 22 from the diameter DI to the diameter D2, and after an inner wall 342 with a diameter D2 joined in a first time to the expansion zone 341. As illustrated in figure 2, At first, the radial expansion device may comprise an inlet ring 340, usually with a diameter DI, to obtain an axially stretched tube 22 with a diameter DI and a regular profile before the radial expansion. As illustrated in Figure 11, the inlet ring 340 can form an annular chamber 340 ', typically a ring, with an inner surface of inner diameter DI, the corresponding inner surface comprises a plurality of vacuum-placing orifices 3401, this Annular chamber is placed at a pressure Pa <; Atmospheric P, in order to stick the corresponding axially stretched tube 22 against the corresponding inner surface. In fact, this annular chamber 340 'can, on the one hand, make it possible to adjust the diameter of the corresponding axially stretched tube 22, by controlling the pressure Pa, which pressure tends to increase in the presence of a bonding defect, the outside air can pass then through holes 3401; on the other hand, it can allow heating, if necessary, the tube 22 before it enters the expansion zone 341, thanks to a heating means of the annular chamber symbolized by an electrical resistance T '1 in FIG. 11. , the temperature of the corresponding axially stretched tube 22 can be finely adjusted to facilitate its expansion in the expansion zone 341. The radial expansion can be obtained either by keeping the inside of the tube 21, 22, 23 under pressure or by keeping the outside depressed of the tube 23. Preferably, the radial expansion can be obtained by keeping the tube 23 depressed, the radial expansion device 34 comprising an inner wall vacuum 343 thanks to holes 346 placed under vacuum, so that the tube with a diameter DI sticks against the inner wall of the expansion zone 341 and / or against the inner wall 342 with an inner diameter D2, the temperature TI is chosen as low as possible, in order to e obtain a high thermal retraction, however high enough to enable radial expansion. This inner wall 342 with a diameter D2 can be a tubular metal part 345, typically a piece of steel, aluminum, of copper alloy, such as bronze or a cupro-nickel alloy, the part 345 can be a sintered part suitable for letting pass the air. It is possible to treat the surface of this inner wall, which is to decrease the frictional forces between the inner wall 342 and the tube 23, this inner wall being able to be coated at least in part with PTFE, or to give the tube a surface appearance in particular, typically a satin appearance or a "mirror polish" appearance, then the interior wall comprises a relief or surface roughness apt to provide this appearance. In general, the radial expansion stage can guarantee, in the expansion area 341, an increase in diameter from DI to D2 or ΔD = D2-D1 of at least 10 mm, at a distance Ll less than 250 mm , and typically less than 100 mm, in order to obtain the? D / L1 ratio as high as possible and typically higher than 1/25, and so the corresponding radial expansion comprises a small or negligible axial expansion component. The upper limit of the ratio? D / L1 varies according to the thermoplastic matter that forms the tube; typically, it can be of the order of 3. Thanks to this separation between previous axial stretching and subsequent radial expansion is that the capsules according to the invention can be retracted in a neck only radially, without significant modification of the axial component according to the height of the capsules, so that the axial position of these capsules in the neck remains the same after the thermal retraction and that any image printed on these capsules also remains intact in the axial direction. According to the invention, and as illustrated in Figure Ib, the radial expansion stage can comprise an auxiliary cooling thanks to an auxiliary cooling means 347, to obtain, at the outlet of the radial expansion device 34, an expanded tube radially 23, at a temperature T2 typically included between 10 ° C and 60 ° C, and usually at room temperature, the auxiliary cooling means 347 comprising a cooling of the tubular metal part 345 or of the inner wall 342 of diameter D2, the temperature T2 has to be quite low so that the tube obtained at the outlet of the radial expansion device 34 can be pulled with the axial pulling means 35, without risk of rupture or elongation of the radially expanded tube 23 with a diameter D2. Thus, the tubular metal part and the inner wall can have a temperature gradient, with an input with a relatively hot diameter DI and an outlet with a relatively cold diameter D2. According to the ntion, the diameter OD of the hole forming the corresponding extruded tube 21 can typically range from 20 mm to 50 mm, and its slot width or thickness EO can typically range from 0.5 mm to 3 mm, with the In order to obtain a flow of plastic material from the extruder 30, which typically ranges from 10 kg to 100 kg of plastic material per hour. Likewise, the diameter DI of the axially stretched tube 22 can typically range from 5 to 20 mm, and its thickness typically ranges from 0.2 mm to 0.6 mm, with a Dl / DO ratio equal to 0.6 at most and a ratio The / EO equal to 0.6 as a maximum. The diameter D2 of the radially expanded tube 23 can typically range from 20 mm to 50 mm and its thickness E2 ranges from 0. 05 mm to 0.35 mm, and typically from 0.075 mm to 0.15 mm, with a D2 / D1 ratio at least equal to 2 and a ratio E2 / E1 equal to 0.6 as a maximum. As illustrated in Figure 9a, the radial expansion device 34 can be positioned at a distance L from the orifice, the radial expansion device 34 is typically movable in the axial direction 25, the corresponding distance L is chosen, in particular according to the material plastic, in order to obtain a sufficient degree of axial stretching and in order to obtain a sufficient cooling of the axially stretched tube 22. The relative axial mobility of the radial expansion device 34 with respect to the hole has been represented with the double arrow " < - > " In the same way, the cooling means 32 can be positioned at a distance LO < L of the orifice, the distance LO is chosen, in particular according to the plastic material, in order to obtain a sufficient degree of axial stretching, the cooling means is typically movable according to the axial direction 25, in order to obtain an adjustment of the diameter DI at the entrance of the radial expansion device 34 by a displacement? LO of the cooling medium around the distance LO. The relative axial mobility of the cooling means 32 with respect to the hole has been represented with the double arrow "< - >" in figures 9b to 9d. According to the method of the invention, and as illustrated in FIGS. 9b to 9d, the radial expansion device may comprise the annular chamber 340 'placed under vacuum, at the pressure Pa, and the displacement? LO may depend particularly on the pressure Pa, each pressure increase Pa implies for the tube axially stretched a negative deviation ΔD of diameter with respect to the diameter DI, the negative deviation ΔDl can be corrected by a displacement ≤ negative LO in order to increase of ΔDl the diameter of the tube stretched axially. In addition, the displacement ΔLO can depend particularly on the axial pulling force Ft exerted by the pulling means, each positive increase or deflection ΔFt of the force Ft usually involves a positive deflection ΔDl of the diameter of the axially stretched tube 22 (with respect to the diameter DI of the inlet ring (340, 340 '), the axially stretched tube 22 thus has a diameter greater than the inlet diameter of the radial expansion device 34, the positive deviation? Ft can be corrected by a displacement? the positive in order to decrease the diameter of the axially stretched tube from? Dl Thus, this embodiment of the manufacturing method according to the invention is very advantageous because it comprises a means of permanent adjustment, which leads to a great regularity of production, and in addition this means of adjustment considerably reduces the start-up time of the procedure as well as the adjustment time during a bio of plastic material. According to the invention, the thermoplastic material 20 may comprise or consist of at least one first thermoplastic material 200 having a glass transition temperature Tg at least equal to 40 ° C, and usually chosen from: PET, PVC, PS, PMMA, or its mixture, or copolymers of PET, PVC, PS, PMMA, in order to obtain capsules of small thickness that have a good mechanical strength in themselves and that are suitable for use in a capped line. However, the thermoplastic material 20 may comprise or consist of at least one second thermoplastic material 201 having a glass transition temperature Tg of less than 50 ° C and typically less than 10 ° C, and typically chosen among the polyolefins as PE, PP, PB, or between ethylene copolymers such as EVA, EMA, EAA, ethylene and propylene copolymers, or between thermoplastic elastomers such as SIS, SEBS, or their mixture. In the case where only the second plastic material would be used, it may be necessary to have a greater thickness to achieve a good mechanical strength of the capsule. Advantageously, the thermoplastic material 20 can comprise a mixture of the first thermoplastic material 200 and the second thermoplastic material 201, the mixture comprises at least 50% by volume of this first thermoplastic material 200 and from 10 to 50% by volume. volume of the second thermoplastic material 201, in order to obtain capsules 1, Ib, lc or caps which have a range of textures and flexibility according to the relative percentage in the first 200 and second 201 thermoplastic materials. Thus, the invention can be used with a large number of thermoplastic materials as long as their mechanical characteristics are compatible with the formation of capsules. Indeed, the invention can potentially be applied to any thermoplastic material capable of being axially stretched and of radially expanding according to the invention. According to one embodiment of the invention, the thermoplastic material 20 can form or comprise a multilayer material, the multilayer material comprises a first layer constituted by the first thermoplastic material and a second layer constituted by the second thermoplastic material, this multilayer material can include an adhesive inner layer.

In addition, all or part of the thermoplastic material 20 may contain a micronized charge typically chosen among talc, calcium carbonate, barium sulfate, titanium oxide, organic or mineral pigments, clay nanoparticles, in order to giving color to the thermoplastic material 20. In this way, thanks to a wide selection of thermoplastic materials and fillers, in particular of mineral fillers, the invention offers virtually infinite possibilities with regard to the sensory properties of the manufactured capsules, in particular to the properties of touch or appearance, of "sonority", of cutting with a knife, etc. In particular, these capsules or caps can have a great softness of touch, very different from the usual touch of the plastic materials, or also a touch or grip similar to those of the tin-based capsules. The applicant assumed that this could be related to the probably heterogeneous mixture of two materials with different Tg. According to one embodiment of the invention, and as illustrated for example in figure 7, in step c) of cutting, the piece of tube 24 can be a piece of tube called "short" 240, the appropriate length of the piece of tube 24 is typically chosen close to the height H of the capsule. In this case, in step d) of forming, a tablet 5, flat or with a curved rim is provided, intended to form the head 11 of the capsule 1, Ib, lc or of the cap la, and the tablet 5 is assembled to the corresponding skirt blank 26, typically by heat sealing, with the help of a matrix 42 cooperating with the mandrel 40, the cooperation of this matrix 42 with the mandrel 40 optionally form or give relief to this chip 5. The corresponding chip 5 can be obtained by cutting a sheet material 52, optionally transparent, in a material chosen from plastic materials, metal bands or sheets, paper or cardboard or multilayer assemblies of these materials. This method is advantageous for obtaining composite capsules whose head 11 has a nature different from that of the skirt 12. Optionally, the tablet 5 can be constituted by a controlled tablet. This tablet can comprise any type of system that allows in particular to identify the capsule, to follow and guarantee the tracing ability of the packaged products, to form an anti-fraud and anti-theft means. According to another embodiment of the invention illustrated in figures 5a to 5c and in figures 8a to 8e, the tablet 5 can be replaced by an insert 5 'comprising a head 50 and optionally a skirt 51, the insert 5' is located at the upper end of the shaping mandrel 40, typically prior to the thermal retraction of the piece of tube 24, in order to assemble the insert 5 'to the thermally retracted skirt blank 26, optionally with the aid of an adhesive layer or heat seal. Usually, this insert 5 'is an insert molded of thermoplastic material, so that it is possible to obtain an assembly of the piece "short" 240 at its upper end to the skirt 51 of the insert 5', thanks to the contribution of heat Q during the thermal retraction illustrated in figure 5b, or optionally thanks to a complementary thermal input in the upper part of the capsule. The insert 5 'can comprise a thread 510 and present a sealing means 511, in order to form a stopper capsule Ib. See figure 5a. According to another embodiment of the method according to the invention, and as illustrated in FIG. 6 a, in step c) of cutting the process, the piece of tube can be a piece called "long" 241, the appropriate length chooses above the height of the capsule, the piece of tube 241 comprises a lower part 242 intended to form the skirt 12 of the capsule 1, Ib, lc or of the corresponding cap la, and an upper part 243 intended to form the head 11 of capsule 1, Ib, lc or the cap la, the head 11 is formed by compression or molding of the upper part 243 between a die 42 and a head 400 of the mandrel 40. In this embodiment, the upper part 243 has a length calculated as supplying the sufficient amount of plastic material to form the head 11, without there being any useless over-thickness or any over-thickness which makes the capsule unusable. However, as illustrated in Figures 8a to 8e, from a "long" piece 241, it is possible to form a stopper capsule Ib in which the insert 5 'is completely covered by a layer of thermoplastic material coming from the piece. 24. In addition, as illustrated in Figure 6b, an auxiliary piece 6 that typically forms a pattern, an ornament or an inspection means, can be inserted into the matrix 42 before compression, in order to simultaneously form the head 1 and assembling to the head 11 the auxiliary piece 6. Indeed, it is advantageous to take advantage of the presence of a matrix 42, which can optionally be heated, to fix a complementary element on the head of the capsule without having to add an additional stage to the process . Generally, capsules 1 are usually decorated or printed. According to the invention, the impression 13 can be formed in the piece of tube 24, and / or in the skirt 12, and / or in the head 11, and / or in the thermally retracted skirt blank 26, either before or after having assembled or formed the head 11 of the capsule 1, Ib, lc or of the cap la. Indeed, the invention makes it possible to print the pieces of tube 24 insofar as it allows to avoid any further axial deformation, the radial deformation during the thermal retraction in the neck is limited in itself thanks to the geometry of the neck, and because , as illustrated for example in Figures 4e and 4f, the average diameter D3 of the skirt 12 of the capsule is chosen according to the geometry of the neck 8 to be covered, and of its minimum diameter D4 of the neck 8, the capsule skirt 1 after thermal shrinkage must have in particular this diameter D4, without counting the thickness of the capsule. It is important that this diameter D4 is still greater even than the diameter DI of the tube before the radial expansion, so that the capsule is effectively glued against the entire neck that has to be covered. To form the print 13, radiation-curable inks, usually UV inks, can be used so that the print 13 is typically formed at a temperature lower than the temperature at which the capsule thermally retracts. As shown in FIG. 4e, printing 13 can be formed using an inkjet printing device 7 or by transfer comprising a plurality of N print nozzles 70 in parallel according to the corresponding axial direction or height H, the plurality comprises a nozzle density of at least one nozzle 70 per mm, the device is typically controlled by a computer 71 equipped with numerical storage means of the printed patterns 130 that are to be reproduced in the capsule 1, Ib, lc or in the the cap, in order to be able to print simultaneously several different motifs 130, of being able to change the printed motif 130 immediately and thus print series of capsules 1, Ib, or cap optionally very short. With the arrangement of several ramps 73 of print nozzles 70 in parallel, it is possible to print in parallel identical or different patterns, which offers a particularly flexible and advantageous method, since the printing can be made dire from a pattern transmitted by The buyer of these capsules, and this from the reception 'of the reason. According to the invention, all or part of the thermoplastic material 20, 200, 201 can be colored in the mass. In this case, it is either a matter of forming a background color on which the print is formed, or to optionally form a color capsule but not printed. Advantageously, the multilayer material may comprise an outer layer of a plastic material, typically polar or with high surface energy, in order to be suitable for printing and to lead to an adornment adhering to the outer layer. It may comprise an inner layer constituted by an activatable adhesive, in order to be able to locally glue the capsule to the neck, typically by local heating. As illustrated in Figures 5d and 5f, the skirt 12 comprises an easy opening means 14 typically comprising two lines of weakness 140 spaced apart so as to form an opening tab 141 provided with a manual grasping end 142. In a traditional manner, the lc overcap capsules used in the wine bottles covered with a cork stopper are cut with a knife and do not comprise any means of easy opening. However, the invention encompasses any type of capsule provided with an easy opening means. As illustrated in Figures 12a and 12b, the axial traction means 35 may comprise two drive wheels 350 or two tracks. The Applicant noted that it was possible to pull the radially expanded tube 23 through the use of a pair of wheels 350, the tube collapses at the outlet of the radial expansion device 34, without this being detrimental to the appearance of the final capsule 1, the, le, lc. This means of traction is advantageous in particular because of its simplicity and the fact that it occupies little space. Another object of the invention is constituted by lc heat-shrinkable overcapping capsules, obtained according to the method of the invention, and typically intended to overwrap sealed bottles, with a height H between 20 and 100 mm and having a Skirt thickness 12 comprised between 0.05 mm and 0.5 mm. Another object of the invention is constituted by heat-shrinkable overcapping capsules obtained according to the invention, with a height H included between 20 and 60 mm and having a skirt thickness 12 comprised between 0.05 mm and 0.5 mm. Another object of the invention is constituted by shrinkable heat-sealing capsules Ib obtained according to the invention. These capsules, comprising an insert as illustrated in Figures 5a to 5d, have a height H included between 20 and 100 mm and have a skirt thickness 12 included between 0.05 mm and 0.5 mm for the lower part of the skirt not assembled to the insert 8. Another objective of the invention is constituted by heat-shrinkable caps for effervescent wines or pressurized carbonated drinks obtained according to the invention, with a height H included between 60 mm and 200 mm and having a skirt thickness included between 0.1 mm and 1.0 mm.

Such caps are illustrated in Figures 5e and 5f. Another objective is constituted by capsules 1, Ib, le or caps the skirt 12 of heat shrinkable thermoplastic material 20, the head 11 is optionally made with the corresponding heat shrinkable thermoplastic material 20, in which the thermoplastic material 20 can comprise a mixture: - of a first thermoplastic material having a glass transition temperature Tg of at least equal to 40 ° C and typically chosen from: PET, PVC, PS, PMMA, or its mixture, or its copolymers, - and a second material thermoplastic having a glass transition temperature Tg lower than 50 ° C and typically lower than 10 ° C and typically chosen among polyolefins such as PE, PP, PB, or among ethylene copolymers such as EVA, EMA, EAA, or between ethylene and propylene copolymers, or between thermoplastic elastomers such as SIS, SEBS, or their mixtures. The mixture may comprise at least 50% by volume of the first thermoplastic material 200, and from 10 to 50% by volume of the second thermoplastic material 201. Whatever the type of capsule, the capsules or caps according to the invention may internally comprising a reactive heat-resistant coating layer, usually a molten layer (hot melt), for the purpose of fixing all or part of the capsules or caps on the flanges. This means still reinforces the inviolable character of the caps or capsules according to the invention, making it impossible to separate the capsule and the neck without causing its destruction, at least partially and visibly. Another object of the invention comprises capsule bars 1, Ib, lc or caps according to the invention, the corresponding bars are formed by a stack of capsules 1, Ib, le, or frusto-conical caps, typically printed on their outer surface.

EXAMPLES OF REALIZATION A) Manufacture of pieces of tubes 24 Most of the tests, with regard to the manufacture of the pieces of tubes 24, were made with the device 3 represented in Figure Ib. Other tests were performed with the device of figure lc. In these tests, an extruder 30 with a maximum flow rate of 50 kg / h of thermoplastic material 20 was used, which screw had a "length / diameter" ratio of 30. An annular orifice 31 or extruder head with a diameter OD was used. of 27 mm, the extruded tube 21 formed had an EO thickness of 0.7 mm and a temperature T typically ranging from 190 ° to 240 ° C. At the exit of the annular hole 31, the radial expansion stage was performed at the axial distance LO, a distance that typically ranges from 0.3 m to 0.6 m. Then, the axial stretching step was blocked by the use of expelled air 320 as the cooling means 32 of the axially drawn tube, so that the axially stretched tube 22 is at a temperature ranging from 140 ° C to 160 ° C and present a diameter equal to the diameter DI of the input ring 340, 340 'of this radial expansion device 34. This cooling means 32 was axially movable, in order to be able to adjust the diameter of the axially stretched tube 22 with respect to the ID of the entry ring 340, 340 '. This stretched tube 22 had at the entrance of the radial expansion device 34 a thickness of 0.35 mm, which corresponds to a S0 / S1 ratio of 3.86 and translates a relatively high axial stretch index. A radial expansion device 34 of 500 mm long, axially movable, separated from the orifice 21 from a distance L typically ranging from 0.5 m to 1 m, and equipped with an input ring 340 with a diameter ID equal to 14 was used. mm and an inner wall 342 with uff inner diameter D2 of 35 mm.

The radial expansion device 34 used was the one shown in FIG. 2 or, preferably, the one of FIG. 11 with its expansion zone 341 extending over the distance Ll equal to 35 mm, so that the ratio? D / Ll is worth 0.6 = (35-14) / 35. Tests were also carried out with a similar device 34 whose internal profile is shown as a dotted line in figure 2, and in which the expansion zone 341 extends over the distance L'l >; Ll, the distance L'l is equal to 80 mm. In this case, the ratio? D / Ll is 0.26 = (35-14) / 80. For the tests, a vacuum of 0.35 bar was maintained thanks to the vacuum outlet 349. The device 34 was cooled with water, so that the radially expanded tube 23 leaves the device at room temperature, typically at about 25 ° C. which corresponds to a drop in the tube temperature of about 120 ° C between the inlet and outlet of the radial expansion device 34. This radially expanded tube 23 had a thickness E2 of 0.14 mm. As a means of axial traction 35, a two-wheel system or optionally a system of two caterpillars that rotate in the opposite direction was used and as they approach, they drag the expanded tube 23 to an axial length sufficient to exert on the surface of the expanded tube 23 a minimum pressure so as not to indicate the surface of the tube. This axial traction system, as well as the chopping means 36 that follows, are devices known per se. Typical development of a test on the laboratory device used: Tests were also carried out on an industrial line, with an extruder flow D and a traction speed V 5 times larger. Pieces of "long" tubes 24, 241 of 60 mm long were cut, with a view to manufacturing overcapping capsules with heat shrinking lc lc according to the procedure illustrated in Figures 8a to 8e.

B) Nature of the thermoplastic material used in the tests A large number of tests were carried out. The compositions are usually mixtures: - based on a first thermoplastic material PMT 200, - based on a second thermoplastic material SMT 201. These compositions% by weight - can also comprise CM mineral fillers or fillers or various adjuvants. For these non-limiting tests, the following products were used: - as the first PMT plastic material: A = crystal polystyrene (Lacqréne 1811 of Atofina) B = copolyester (Embrace 22608 of Eastman) - as second plastic material SMT: CEVA (Escorene UL00218CC3 of Exxon Mobil Chemical) D = EVA (Evatane 1020 VN5 of Atofina) E = SEBS (Kraton G1652 of Shell) F = SIS (Kraton Dllll of Shell) G = PE (Engage 8400 Dupont Dow Elastomer) - as mineral charge: H = Talc (LOMOOS de Luzenac) I = White pigment of titanium oxide C) Manufacture of capsules 1 from pieces of tubes 24 A device 4 for shaping pieces of tube 24 was used comprising an endless chain conveyor 41 that rotates about its axis 410 and provided with four forming mandrels 40 typically located at 90 ° to each other, as shown in Figures 6a, 6b and 7. The procedure was performed, as illustrated schematically in Figure 6a, according to a first embodiment of the invention. In this particularly economical process, the head 11 of the capsule is formed from a piece of tube 24 called long 241 leading to a blank part of retracted capsule 27 whose upper part 270 forms a reserve of matter to form the head 11 of the capsule, thanks to the compression of a matrix 42. From a piece of tube 24 having the same measurement, capsules of various sizes were manufactured, playing simply with the measurements of the shaping mandrel 40 and the head forming matrix 42. A first variant of this first embodiment illustrated in FIG. 7 was also made. According to this variant, it is possible to start with a piece of tube 24 called short 240 and in this case, the head 11 of the capsule is formed from a tablet 5 typically made with a material different from that of the skirt 12. It is also he made a second variant of this first modality illustrated in figure 6b. According to this variant, whenever a compression matrix 42 is used, it is possible to introduce in the head of the capsule another element capable of being fixed hot and / or by axial compression.

Once formed and typically printed, the overcap capsules lc could be used as such. The method according to the invention was also used to form caps according to FIGS. 5e and 5f, which caps were provided with first opening means 14, as illustrated in FIG. 5f. The process according to the invention was also used to form plug caps with thread Ib. According to a first variant of the method illustrated in FIGS. 5a to 5d, a "composite" plug capsule was formed in which the head 11 of the capsule Ib is formed by the head 50 of the threaded insert 5 '. According to a second variant of the procedure illustrated in FIGS. 8a to 8e, the insert 5 'was totally hidden externally by the capsule element formed from the corresponding piece 24.

D) Results obtained. Whatever the type of capsule Ib, le or capsule, the results obtained refer to: 1 - the ease of manufacture and in particular the aptitude for expansion, 2 - the properties of the capsule in terms of: a) retraction capacity: in particular during capsulation b) mechanical properties: rigidity of the capsule, ease of tearing the capsule, etc. c) touch or "grasping" d) ability to cut with a knife or "cutting capacity", in particular in the case of overlapping capsules le.

The results in relation to tests 2 to 14 are considered in relation to test 1.

ADVANTAGES OF THE INVENTION The invention has great advantages: on the one hand, the process according to the invention is an economic process. In fact, this method is not very demanding in terms of investment, and, in particular, does not require the presence of an irradiation device. It also provides high productivity while needing a relatively small amount of plastic material per capsule as well as the use of ordinary plastic materials, - on the other hand, the process according to the invention allows to manufacture all types of capsules, which is Capping capsules Ib, overcapping capsules or caps for the over-packing of effervescent wines, - furthermore, the method according to the invention makes it possible to obtain decorated or printed capsules whose decoration is not subjected to any axial distortion during the retraction of the capsule in the neck, - finally, the invention allows to obtain, on request, and as is illustrated in a non-limiting manner with the embodiment examples, a wide variety of capsules, including similar capsules, by their touch or grip, to tin-based metal capsules, so that the procedure that potentially allows all types of demand can guarantee the fulfillment of personalized and individualized needs.

LIST OF REFERENCES Capsule with heat shrink skirt 1 Cap with heat-shrinking skirt Capsule cap with heat shrinking skirt Ib Overcap capsule with heat shrinking lc skirt Axial direction of the capsule or cap 10 Head 11 Heat-shrink skirt 12 Printing on 11, 12, 24 13 Printed reason 130 Easy opening medium 14 Line of weakness 1 140 Opening tab 141 Gripping end of 141 142 Capsule precursor and cap 1, 1 '2 Thermoplastic material of 21, 22, 23 20 First thermoplastic material '200 Second plastic material 201 Extruded tube (SO, DO, E0, T0) 21 Axially stretched tube (SI, DI, El, TI) 22 Radially expanded tube (S2, D2, E2, T2) 23 Pieces of tube 24 Piece "short" 240 Piece "long" 241 Bottom of 241 242 Top of 241 243 Axial direction of 21, 22, 23, 24 or of 31, 32, 33, 34 25 Piece of rough 1, the, Ib, lc with thermally retracted skirt 26 Rough piece with thermally retracted skirt formed from 241 27 Upper part destined to form the head 11 270 Device or piece manufacturing line 23 3 Extruder 30 Hole or head of extruder 31 Medium or cooling device 32 Projection of air or water typically annular 320 Water circulation 321 Cooling ring 322 Calibration ring with a diameter DI 33 Radial expansion device 34 Inlet ring with diameter DI 340 Vacuuming holes 3401 Expansion zone 341 Vacuuming holes 3410 Annular camera with control of T and P 340 ' Interior wall with a diameter D2 342 Interior wall vacuum 343 Expansion chamber "= 341 + 342 344 Internal tubular metal part 345 Vacuuming holes of 343, 345 346 Auxiliary cooling medium 347 External vacuum chamber 348 Vacuum outlet 349 Axial tensile means 35 Wheel or drive belt 350 Cutting medium of 23 in 24 36 Accumulator 24 37 Device or line for shaping pieces 24 4 Mandrel forming 24 40 Mandrel head 400 Endless chain conveyor with N mandrels or angular positions (360 ° / N) 41 Axis of rotation 41 410 Matrix of formation or fixation of the head 11 42 Pickup assembled to 240 to form 11 5 Insert assembled to 240 to form 11 5 ' Head 50 Skirt 51 Thread of 51 510 Sealing medium of 50 or 51 511 Sheet material 52 Auxiliary part 6 Printing device 7 Spray point print nozzle 70 Automatic numerical control means -computer 71 Motor for rotating the capsule 72 Axial ramp of nozzles 70 (printhead.) .73 Tank shot 8 Chaplet of champagne bottle 8 ' Cork stopper 80 Stopper with head for bottle of champagne 80 ' Capsule 1, la, Ib, lc retracted in 8 9 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 (48)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Procedure for manufacturing capsules or caps with heat-shrinkable skirt, comprising: a) an extrusion step in which an extruded tube is formed thermoplastic material by extrusion, with the help of an orifice fed by an extruder that works at the temperature TO chosen according to the softening or melting temperature Tf of the corresponding thermoplastic material, the corresponding hole has a diameter DO, a slot width or thickness EO and a corresponding section with an area SO, b) a radial expansion stage of the corresponding extruded tube, to form a radially expanded tube with a diameter D2, a thickness E2 and a corresponding section with an area S2, thanks to a device of radial expansion, c) a chopping stage, in which the expanded tube is cut into pieces of t ubo of appropriate length, the radially expanded tube is pulled with an axial pulling means, d) a step of forming the tube pieces, wherein each piece of tube is placed in a typically frustoconical forming mandrel and shaped by thermal retraction to form a thermally retracted capsule blank, furthermore, a head is typically assembled to the corresponding blank or formed from the corresponding blank, in order to obtain a capsule or a heat-shrinkable cap equipped of the corresponding head and of a skirt, and typically apt to receive an impression, and characterized in that, at the outlet of the orifice of the extruder, between stage a) of extrusion and stage b) of expansion, a step of axial stretching of the extruded tube, in order to obtain an axially stretched tube with a diameter DI typically lower than OD and D2, a thickness El typically lower than EO, and a corresponding section with an SI area, such that SO / SI is typically included among "2 and 10, the corresponding stages of extrusion, axial stretching, radial expansion and cutting are performed by continuous movement, in order to obtain capsules or caps that are both economical, easy to retract thermally and with a stable axial measurement. to avoid any axial distortion, in particular any axial distortion of the impression 2. Method according to claim 1, characterized in that the axial stretching step is delimited, at the rear, with a cooling zone in which a medium When the temperature of the corresponding axially drawn tube is lowered to a temperature TI, the temperature TI is chosen: a) high enough to be at least equal to the glass transition temperature Tg or to the melting temperature Tf of the corresponding thermoplastic material , in order to be able to perform the subsequent radial expansion stage, b) quite low enough to interrupt the corresponding axial stretching stage and thus fix the diameter of the corresponding axially stretched tube to a typically predetermined diameter DI. Method according to claim 2, characterized in that the temperature TI is such that? T, equal to TO-Tl, ranges from 30 ° C to 150 ° C and usually from 45 ° C to 100 ° C ° C. Method according to any of claims 2 to 3, characterized in that the cooling medium comprises an external projection of air or water, typically annular. Method according to any of claims 2 to 4, characterized in that the cooling medium comprises a ring cooled with air or with water. Method according to claim 5, characterized in that the ring comprises a part with a diameter DI, in order to form a calibration ring from which a tube with a diameter DI, typically axially stretched and cooled to the IT temperature. Method according to any of claims 2 to 6, characterized in that the cooling means comprises a projection of air or water inside the corresponding axially drawn tube, usually by means of a conduit passing through the orifice. Method according to any of claims 2 to 7, characterized in that the radial expansion device, initially supplied with tubes drawn axially at the temperature TI, comprises a radial expansion chamber provided with an inner wall with a diameter D2 joined in a first time to an expansion zone intended to pass the axially drawn tube from the diameter DI to the diameter D2. 9. Method according to claim 8, characterized in that in a first time, the radial expansion device comprises an input ring, typically with a diameter DI, to obtain an axially stretched tube with a diameter DI and a regular profile before the radial expansion. 10. Method according to claim 9, characterized in that the inlet ring forms an annular chamber, usually a ring, of inner surface with internal diameter DI, the inner surface comprises a plurality of vacuuming orifices, the annular chamber it puts pressure on Pa <; Atmospheric P, in order to stick the tube stretched axially against the inner surface. 11. Method according to claim 1, characterized in that the radial expansion is obtained either by keeping the inside of the tube under pressure, or by keeping the outside of the tube depressed. 12. Method according to claim 11, characterized in that the corresponding radial expansion is obtained by keeping the tube depressed, the radial expansion device comprises an inner wall vacuuming vacuum holes, so that the tube with a diameter DI glue against the inner wall of the expansion zone and / or against the inner wall with an inner diameter D2, the temperature TI is chosen as low as possible, in order to obtain a high thermal retraction, however high enough to enable the corresponding radial expansion. 13. Method according to claim 12, characterized in that the inner wall of diameter D2 is a tubular metal part, typically a piece of steel, aluminum, of copper alloy, such as bronze or a cupro-nickel alloy, this piece can be a sintered part suitable for letting the air pass, the inner wall can be surface treated to decrease the frictional forces between the inner wall and the tube, or to give the tube a particular surface appearance. Method according to any one of claims 1 to 13, characterized in that the step of radial expansion guarantees, in the expansion zone, an increase in diameter from DI to D2 or ΔD = D2-D1 of at least 10 mm , in a distance Ll less than 250 mm, and usually less than 100 mm, in order to obtain the ratio? D / Ll as high as possible and usually higher than 1/25 and thus the radial expansion it comprises a component of small or negligible axial expansion. 15. Method according to any of claims 1 to 14, characterized in that the radial expansion stage comprises an auxiliary cooling thanks to an auxiliary cooling means, to obtain, at the outlet of the corresponding radial expansion device, a radially expanded tube. , at a temperature T2 typically included between 10 ° C and 60 ° C, and usually at room temperature, the auxiliary cooling medium typically comprises a cooling of the tubular metal part or the inner wall with a diameter D2 , the temperature T2 has to be quite low so that the tube obtained at the outlet of the radial expansion device can be pulled with the axial traction means, without risk of rupture or elongation of the radially expanded tube with a diameter D2. 16. Method according to any of claims 1 to 15, characterized in that the OD diameter of the orifice forming the extruded tube typically ranges from 20 mm to 50 mm, and its slot width or EO thickness typically ranges from 0.5 mm. to 3 mm, in order to obtain a flow of plastic material from the extruder that typically ranges from 10 kg to 100 kg of plastic material per hour. Method according to any of claims 1 to 16, characterized in that the diameter DI of the axially stretched tube is typically from 5 to 20 mm, and its thickness ranges from 0.2 mm to 0.6 mm, with a Dl ratio. / DO equal to 0.6 as maximum and an E1 / E0 ratio equal to 0.6 as a maximum. Method according to any of claims 1 to 17, characterized in that the diameter D2 of the radially expanded tube typically ranges from 20 mm to 50 mm and its thickness E2 ranges from 0.05 mm to 0.35 mm and typically 0.075 mm to 0.15 mm, with a D2 / D1 ratio at least equal to 2 and an E2 / E1 ratio equal to 0.6 as a maximum. 19. Method according to any of claims 2 to 18, characterized in that the radial expansion device is located at a distance L from the orifice, the radial expansion device is typically mobile in the axial direction, the distance L is chosen, in particular according to the plastic material, in order to obtain a sufficient degree of axial stretching and in order to obtain a sufficient cooling of the axially stretched tube. 20. Procedure in accordance with the claim 19, characterized in that the cooling medium is located at a distance LO < L of the orifice, the distance LO is chosen, in particular according to the plastic material, in order to obtain a sufficient degree of axial stretching, the cooling means is typically movable in the axial direction, in order to obtain a diameter adjustment DI at the entrance of the corresponding radial expansion device by a displacement of the cooling medium around the corresponding distance LO. 21. Procedure in accordance with the claim 20, characterized in that the radial expansion device comprises the annular chamber placed under vacuum, at the pressure Pa, and in which the corresponding displacement? LO depends particularly on the pressure Pa, each pressure increase Pa implies for the axially stretched tube a Negative deviation? Dl in diameter with respect to the diameter DI, the negative deviation? Dl can be corrected by a displacement? LO negative in order to increase the diameter of the axially stretched tube from? Dl. 22. Method according to any of claims 20 to 21, characterized in that the displacement? LO depends particularly on the axial tensile force Ft exerted by the traction means, each positive increase or deviation? Ft of the force Ft typically involves a positive deviation? Dl in diameter with respect to the diameter DI of the tube, the axially stretched tube thus has a diameter greater than the inlet diameter of the radial expansion device, the positive deviation? Ft can be corrected by a displacement? LO positive with in order to decrease the diameter of the axially stretched tube from? Dl. Method according to any of claims 1 to 22, characterized in that the thermoplastic material comprises or consists of at least one first thermoplastic material having a glass transition temperature Tg of at least equal to 40 ° C, and typically chosen from: PET, PVC, PS, PMMA, or its mixture, or copolymers of PET, PVC, PS, PMMA. 24. Method according to any of claims 1 to 23, characterized in that the thermoplastic material comprises or is constituted by at least one second thermoplastic material having a glass transition temperature Tg of less than 50 ° C and typically less than 10 ° C. ° C, and typically chosen from polyolefins such as PE, PP, PB, or between ethylene copolymers such as EVA, EMA, EAA, ethylene and propylene copolymers, or between thermoplastic elastomers such as SIS, SEBS, or its mixture. Method according to claims 23 to 24, characterized in that the thermoplastic material comprises a mixture of the first thermoplastic material and the second thermoplastic material, the mixture comprises at least 50% by volume of the corresponding first thermoplastic material and from 10 to 50% by volume of the corresponding second thermoplastic material, in order to obtain capsules or caps which have a range of textures and flexibility according to the relative percentage in the corresponding first and second thermoplastic materials. Method according to claims 23 to 24, characterized in that the thermoplastic material forms or comprises a multilayer material, the multilayer material comprises a first layer constituted by the first thermoplastic material and a second layer constituted by the second thermoplastic material, the material Multilayer may include an inner adhesive layer. 27. Method according to any of claims 1 to 26, characterized in that all or part of the thermoplastic material contains a micronized charge typically chosen between talc, calcium carbonate, barium sulfate, titanium oxide, organic pigments or minerals, the nanoparticles of clays, in order to give color to the thermoplastic material. 28. Method according to any of claims 1 to 27, characterized in that in step c) of chopping, the piece of tube is a piece of tube called "short", the appropriate length of the piece of tube is typically chosen close to the height H of the capsule, in which, in the stage d) of forming, a pad is provided, flat or with curved flange, intended to form the head of the capsule or cap, and wherein the tablet is assembled to the skirt blank, typically by heat sealing, With the help of a matrix cooperating with the mandrel, the cooperation of the matrix with the mandrel optionally forms or gives relief to the tablet. 29. Method according to claim 28, characterized in that the tablet is obtained by cutting a sheet material, optionally transparent, in a material chosen from plastic materials, metal bands or sheets, paper or cardboard or multilayer assemblies. of these materials, the tablet can comprise any type of system that allows in particular to identify the capsule, to follow and guarantee the drawing capacity of the packaged products, to form an anti-fraud and anti-theft means. 30. Method according to any of claims 28 to 29, characterized in that the tablet is a controlled tablet. 31. Method according to any of claims 28 to 30, characterized in that the tablet is replaced by an insert comprising a head and optionally a skirt, the insert is located at the upper end of the shaping mandrel, typically before retraction of the corresponding piece of tube, in order to assemble the corresponding insert to the corresponding thermally retracted skirt blank, optionally with the aid of an adhesive or heat-sealing layer. Method according to claim 31, characterized in that the insert comprises a thread and has a sealing means, in order to form a plugging cap. 33. Method according to any of claims 1 to 27, characterized in that in step c) of cutting the process, the piece of tube is a piece called "long", the appropriate length is chosen higher than the height of the capsule , the piece of tube comprises a lower part intended to form the skirt of the capsule, or of the corresponding cap, and an upper part intended to form the head of the capsule or the cap, the head being formed by compression or molding of the cap. the upper part between a matrix and a mandrel head. 34. Method according to claim 33, characterized in that an auxiliary piece that typically forms a motif, an ornament or an inspection means is introduced into the matrix before compression, in order to simultaneously form the head and assemble at the head the auxiliary piece. 35. Method according to any of claims 1 to 34, characterized in that the impression is formed on the piece of tube, and / or on the skirt, and / or on the head, and / or on the skirt blank. heat shrink, either before or after having formed the head, the capsule or the cap. 36. Method according to claim 35, characterized in that in order to form the corresponding printing, radiation-crosslinkable inks, typically UV inks, are used, in order that the printing is typically formed at a temperature below the temperature at which it is placed. thermally retracts the capsule. 37. Method according to any of claims 35 to 36, characterized in that the printing is formed through the use of an inkjet or transfer printing device comprising a plurality of N printing nozzles in parallel according to the axial direction or height H, the plurality comprises a nozzle density of at least one nozzle per mm, the device is typically controlled with a computer equipped with numerical storage means of the printed patterns that have to be reproduced in the capsule or in the cap , in order to be able to simultaneously print several different reasons, to be able to change immediately the printed motif and thus print series of capsules or optionally very short caps. 38. Method according to any of claims 1 to 37, characterized in that all or part of the thermoplastic material comprises a thermoplastic material which is colored in the mass. 39. Method according to any of claims 26 to 38, characterized in that the multilayer material comprises an outer layer of a plastic material, typically polar or with high surface energy, in order to be suitable for printing and for driving an ornament that adheres to the outer layer. 40. Method according to any of claims 1 to 39, characterized in that the skirt comprises an easy opening means typically comprising two lines of weakness spaced apart to form an opening tab provided with a manual grip end. 41. Method according to any of claims 1 to 40, characterized in that the axial traction means comprises two driving wheels or two tracks. 42. Heat-shrinkable overcapping capsules obtained by the method according to any of claims 1 to 41, and typically intended to overlap bottlenecks of sealed bottles, with a height H included between 20 and 100 mm and having a skirt thickness comprised between 0.05 mm and 0.5 mm, characterized in that the thermoplastic material comprises a mixture: - of a first thermoplastic material having a glass transition temperature Tg at least equal to 40 ° C and typically chosen from: PET, PVC, PS , PMMA, or its mixture, or its copolymers, - and a second thermoplastic material having a glass transition temperature Tg of less than 50 ° C. 43. Shrinkable heat-shrinkable capsules, characterized in that they are obtained by the process according to any of claims 31 to 32, and of claims 35 to 41, and typically designed to cover bottle necklets, with a height H included between 20 and 100 mm and having a skirt thickness included between 0.05 mm and 0.5 mm for the lower part of the skirt not assembled to the corresponding insert, in which the thermoplastic material comprises a mixture: - of a corresponding first thermoplastic material having a temperature vitreous transition Tg at least equal to 40 ° C, and a second thermoplastic material having a vitreous transition temperature Tg of less than 50 ° C. 44. Heat-shrinkable caps, characterized in that they are obtained by the process according to any of claims 1 to 30 and 33 to 41, and are typically intended to overwrap bottlenecks of effervescent wines or carbonated soft drinks, with a height H included between 60 and 200 mm and having a skirt thickness included between 0.1 mm and 1.0 mm, in which the thermoplastic material comprises a mixture: - of a first thermoplastic material having a glass transition temperature Tg at least equal to the 40 ° C and typically chosen from: PET, PVC, PS, PMMA, or its mixture, or its copolymers, - and from a second thermoplastic material having a glass transition temperature Tg of less than 50 ° C. 45. Capsules or caps with thermal shrinkable thermoplastic material skirt, and with head optionally made with thermoplastic heat-shrinkable material, according to any of claims 42 to 44, characterized in that the first thermoplastic material having a glass transition temperature Tg at less equal to 40 ° C is chosen from: PET, PVC, PS, PMMA, or its mixture, or its copolymers, and in which the second thermoplastic material has a "vitreous transition temperature Tg of less than 10 ° C and it is typically chosen among polyolefins such as PE, PP, PB, or between ethylene copolymers such as EVA, EMA, EAA, or between ethylene and propylene copolymers, or between thermoplastic elastomers such as SIS, SEBS 46. Capsules or caps according to claim 45, characterized in that the mixture comprises at least 50% by volume of the first thermoplastic material, and 10 to 50% by volume of the second thermoplastic material. 47. Capsules or caps according to any of claims 42 to 46, characterized in that they internally comprise a reactivatable thermoadhesive coating layer, typically a molten layer, for the purpose of fixing all or part of the capsules or caps on the flanges. 48. Capsule or capsule bars formed by a stack of capsules or caps according to any of claims 42 to 47, characterized in that the capsules or caps are truncated and typically printed on their outer surface.