FR3000047A1 - PROCESS FOR FORMING AND CLOSING A CONTAINER, AND CORRESPONDING CORK - Google Patents

Abstract

A method of forming and capping a container (50), comprising: - a step of manufacturing an equipped preform assembly, during which a pre-plug (24) is coupled to a neck of a preform so that a passage of the pre-plug allows access to the interior of the preform, - a step of forming the container (50) from the preform, and - a capping step using said pre-plug (24), during from which the passage of the pre-plug (24) is closed.

Description

A method of forming and capping a container, and corresponding cap. FIELD OF THE INVENTION The invention relates to the field of forming and sealing a container, in particular by blowing or by stretch-blow molding from a thermoplastic preform. STATE OF THE ART The increase in the cost of petroleum products means that the cost of the material becomes a major part of the cost of empty containers obtained by stretch-blow molding. These containers may be bottles of drinks, such as bottles of mineral water or fruit juice. The material part in the cost of the empty container can be of the order of 80%. An important need in the field of container blowing is to reduce the amount of material used. As illustrated in FIG. 1, the preforms conventionally used in stretch-blow molding machines comprise a neck which is not deformed during stretch-blow molding. The neck 1 often has a thread 2 which will receive the cap of the future container. Below the thread, the traditional preforms have a circular fixing ring 3 which serves to retain a tamper-proof ring of the plug when the cap is first opened, causing the tamper-proof ring to separate. However, this neck fixing ring projects slightly outside the cylindrical portion of the neck to facilitate the setting up of the plug in the factory with its still unseparated tamper evident ring.

In addition to the fixing ring 3, the traditional preforms also comprise a transport collar 4 located below the fixing ring, that is to say in the axial direction of the preform opposite to the opening of the neck. . The transport collar 4 projects sufficiently radially outwardly of a cylindrical portion of the neck so as to provide sufficient seating for preforms sliding between two rails.

The application US 2011/0225934 describes a preform without a transport flange but with a fixing ring. WO 2009/053921 discloses a preform for blowing a container which lacks a support flange, but which also has an annular ring 15 below the thread. DE 196 54 658 discloses a preform without a transport ring and a method of transporting this preform using a fastening element surrounding the mouth portion of the preform. This hooking member can be removed from the mouth after filling the container. The document contemplates that this fastening element is a retrievable intermediate tool or is disposable. Such a method has several disadvantages. Removing the hooking member after filling and before capping can cause a risk of container contamination due, for example, to the peeling off or tearing of particles from the mouth of the container upon removal of the container. the fastening element. Furthermore, given the amount of containers formed per second, an installation likely to bring the intermediate attachment tools from the filler or corking containers to cross-contamination cleaning of these recycling, and det 3 line preparing the preforms would complex, can generate a between containers. A management of the intermediate tools during their ection of wear of these tools would be machines of beginning of a complex and expensive installation. The assumption of losers is too expensive, losing the interest of using preforms without transport ring. EP 2 447 026 discloses a preform unit comprising a seal which isolates the interior of the preform from the outside so that the sterility conditions of the preform are preserved. WO 2004/087515 discloses a plug for sterile filling of a container.

OBJECT AND SUMMARY OF THE INVENTION An object of the invention is to provide a method of forming and capping a container from a thermoplastic preform, and a stopper specifically adapted to this process which remedy at least one of the aforementioned drawbacks or needs. According to a first aspect, the invention relates to a method of forming and capping a container, comprising: a step of manufacturing an equipped preform assembly, during which a pre-stopper is coupled to a collar; a preform so that a passage of the pre-plug allows access to the interior of the preform, forming the container from the - a preform step, and - a capping step using said pre-plug, during from which we block the passage of the pre-cap.

The forming of a container from a preform may comprise blowing or stretch-blow molding of the container, by a fluid such as air or liquid, for example by the liquid to be packaged in the container. It is understood that the fact of coupling a portion of the future cap on the preform allows to postpone on this pre-cap part of the functions that were provided by the traditional transport flanges. This allows to have simple preforms, without collars, so using less material. The invention makes it possible to retain the advantage of simple preforms without the disadvantages of the prior art. Indeed, the fact that the element coupled to the preform is a part of the future cap makes it possible not to have to recycle this element without consuming unnecessary material. In addition, there is no disassembly. This reduces the risk of pollution or cross-contamination. Advantageously, the capping step is done without uncoupling the pre-plug. Advantageously, the capping step uses a shutter that is fixed sealingly to the pre-plug. According to one embodiment, the step of manufacturing the equipped preform assembly comprises a preform injection phase, the coupling of the pre-cap on the neck taking place during a cooling phase of the preform. preform just injected and before the forming step. Advantageously, the method according to the aforementioned embodiment further comprises a preform recovery phase during which the preform is extracted from an injection mold by being held by a holding means, the mating of the preform. -bouchon the collar taking place before the holding means relaxes the preform. Advantageously, the method comprises a plurality of steps of treatment of the preform or of treatment of the container coming from the preform, and phases of transport of the preform or container between the different processing steps, in which method the plug remains permanently coupled to the preform or the container from the preform. Such processing steps may for example include: heating the preforms above their glass transition, forming the container, filling the container with a liquid, capping the container, and placing labels on the container. According to one embodiment, the capping step comprises a step of irreversibly fixing a tamper-evident element between the pre-plug and the container coming from the preform. In another aspect, the invention relates to a closure cap of an opening of a container neck, comprising a pre-cap, a shutter distinct from the pre-cap, and a tamper-evident member. The pre-cap comprises a coupling means adapted to cooperate with a radially outer region of the neck and a passage 25 arranged so that the pre-cap does not close the opening of the neck. The plug has a closed configuration in which the shutter is attached to the pre-cap and the plug is structured to seal the opening of the neck. The tamper evident member is structured to detect a seal break, when the plug in the plugged state is coupled to the neck and the tamper evident member is attached to the container.

Advantageously, the shutter comprises a sealing portion, a sealing member to the container and a connecting lug connecting the sealing member to the shutter portion of the shutter.

Advantageously, the shutter portion is rigid. Advantageously, the coupling means of the pre-cap is a thread. Advantageously, the pre-plug has positive external means of assistance in manual disconnection.

Said positive external means of manual uncoupling aid may be a side blank equipped streaks oriented to facilitate unscrewing, or a protruding shape adapted to constitute an unclipping pin, as non-limiting examples.

Advantageously, the pre-cap is monobloc. Advantageously, the coupling means of the pre-plug corresponds to a standardized neck, the passage of the pre-plug having a diameter substantially equal to an inner diameter of said normalized neck.

Advantageously, the pre-cap comprises a complementary axial abutment, arranged to cooperate with a rim of the neck, the pre-cap further comprising a first gripping surface disposed at an axial end of the pre-cap, opposite to complementary axial abutment, and adapted to cooperate with a first gripper. Advantageously, the first gripping surface extends radially all around the axis. Advantageously, the first gripping surface extends over a radial distance of at least 1.4 mm.

Advantageously, the pre-cap has an outer lateral flank having a second gripping surface, adapted to cooperate with a second gripper simultaneously with the cooperation of the first gripper. According to one embodiment, the pre-cap comprises at least one sealing lip cooperating with a neck sealing zone, which sealing zone is located on an inner, outer or upper side of the rim. Advantageously, the shutter comprises at least one sealing lip. Advantageously, the shutter comprises a sealing lip which cooperates with an internal diameter of the neck. In another aspect, the invention relates to a container equipped with a pre-cap having a passage allowing access to the interior of the container. The container 15 has a shoulder transition shape marking the transition between the neck having not undergone radial expansion during blow-molding or stretch-blow molding and the container body. The neck is devoid of a grasping member taken from the group containing: a projecting circular ring, a circular rib, a plurality of raised or recessed areas distributed about the axis along a circle perpendicular to the axis of the neck. According to another aspect, the invention relates to a preform equipped with a pre-plug having a passage allowing access to the inside of the preform, in which the preform is devoid of a gripping element taken from the group containing: a projecting circular ring, a circular rib, a plurality of sectors 30 in relief or recessed distributed around the axis along a circle perpendicular to the axis of the neck, and wherein the pre-cap has means external positives for manual decoupling.

According to yet another aspect, the invention relates to a method for preheating a preform, comprising: a step of manufacturing an equipped preform assembly, during which a thermal protection element is arranged around a neck of a preform, and - a step of heating a body of the preform using the preform assembly equipped. It is understood that such a process requires a furnace for heating the preform much simpler than conventional furnaces using preforms without the thermal protection element. For example, in the case of forming the container by stretching the preform, it is desired to heat the body of the preform above the glass transition temperature of the material, while maintaining the neck temperature below that temperature. temperature so that the collar does not deform. Traditional ovens use complex cooling means of the neck relative to the body of the preform processed in the oven. With the above-mentioned preheating method 20, the thermal protection element makes it possible to simplify greatly, or even to eliminate, the cooling means of the neck. Advantageously, the method uses a thermal protection element of a material having a thermal deflection temperature higher than the thermal deflection temperature of the polyethylene terephthalate. Advantageously, the method uses a polypropylene thermal protection element. Advantageously, the thermal protection element used in the aforementioned preheating process is a pre-plug used during a step of plugging a container from said preform. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a preform of the prior art. The present invention will be better understood on studying the detailed description of some embodiments taken as non-limiting examples and illustrated by the appended drawings in which: FIG. 2 is an elevational view of a preform; for the method and plug of the invention, - Figures 3a and 3b illustrate a step of assembling a preform assembly equipped, respectively before and after this assembly, - Figure 4 is a sectional view of a preform assembly equipped in a preform orientation device, - Figures 5a, 5b are two longitudinal sections and Figure 5c is a cross section, each of these three figures illustrating a variant of second pre-plug gripping surface, FIGS. 6a and 6b are respectively a longitudinal section and a view from above, illustrating a transfer of the preform assembly fitted between two star wheels; FIG. 7 is a longitudinal section; FIG. 8 is a longitudinal section of an embodiment of a plug according to the invention and illustrates a step of plugging an embodiment of the process of the invention. and Figure 8a illustrates a plug variant. DETAILED DESCRIPTION As illustrated in FIG. 2, a preform 10 for the method of the invention comprises a neck 11 and a body 12. The neck 11 has a cylindrical portion 13 defining an axis 14 of the preform. A thread 15 protrudes radially outside the cylindrical portion 13 and wraps in one or more helices around the cylindrical portion 13. The preform 10 has an interior volume 16 communicating with the outside through an opening 17 at an upper end 18 of the preform. The neck 11 extends axially from this end 18 to the body 12. This upper end 18 of the preform is called "drinking" 18. It is in this way that the liquid contained in the future container will flow. of this preform 10. The neck 11 is the part of the preform 10 which is intended to be not deformed during a forming step of the container. The body 11 is the part of the preform 10 which will be stretched radially and longitudinally. The cylindrical portion 13 has an outer surface 19 above the thread 15, i.e. on the side of the rim 18 and an outer surface 20 below the thread 15, i.e. in the axial direction opposite to the rim 18. The outer surfaces 19 and 20 are cylindrical. In known manner, the preform 10 is made of thermoplastic material, preferably polyethylene terephthalate (PET). The hollow form can also be obtained by injection into a traditional mold. As illustrated in FIG. 3a, as soon as the temperature of the injected material falls below the glass transition temperature, the core of the mold (not shown) is removed and a mandrel 21 is inserted into the inner volume 16 while the preform 10 is housed in shells (not shown) of the mold.

The mandrel 21 then holds the preform 10 still hot. The preform can then be extracted from the shells (not shown) of the mold while being held firmly. As illustrated in FIG. 3b, the preform 10, still hot, is brought into a cooling device 22 which cools the walls of the body 12 and the neck 11 by direct conduction with a cooled block 23 and by air convection (not shown). . According to the invention, it takes advantage of the time when the preform is still held, either by the mandrel 21 or by the block 23, to assemble a pre-cap 24 on the preform 10. This assembly can for example result from a screwing of this pre-cap 24 on the thread 15. The assembly of the preform 10 and the pre-plug 24, in the coupled state on the preform 10, constitutes an assembly 25, which we will call in this application "preform assembly equipped "25. The fact that the preform 10 during cooling is still held during assembly, allows a particularly simple manufacturing process of" the preform assembly equipped "25. Upon completion of its cooling, this assembly preform equipped 25 is autonomous and can be manipulated, for example by clamps 26 cooperating with the pre-cap 24. As illustrated in FIG. 4, the pre-cap 24 of the "equipped preform assembly 25" comprises a substantially cylindrical portion 28. extending radially to the outside of the neck 11 and has a complementary thread 27 extending radially inwardly of the portion 28 and cooperating with the thread 15. The pre-cap 24 comprises a lug 29 which extends an upper edge of the cylindrical portion 28 and which extends radially inwardly to bypass the rim 18.

This lug 29 is a complementary axial abutment 29 which cooperates with the rim 18 to immobilize the pre-cap 24 on the neck 11 of the preform 10. The pre-cap 24 has a passage 29a which is disposed facing the opening 17 of the preform 10, and preferably in alignment and coaxially with the opening 17 of the preform 10. The substantially cylindrical portion 28 of the conveying member 24 has a lower edge 30 at the opposite axial end. The lower edge 30 is delimited by a first ring-shaped gripping surface 30a substantially perpendicular to the axis 14. The first gripping surface 30a plays the same role as the lower surface of the conventional flanges. preforms. It can be used, for example, to guide the preform assembly fitted between two rails (not shown). FIG. 4 shows a preform orientation device 31 which consists of two parallel cylindrical rollers 32 approximately 3 meters long and slightly inclined relative to the horizontal. The diameters of the rollers 32 may be, for example, from 20 to 100 mm in diameter, in particular from 70 to 90 mm in diameter. The two rollers 32 are separated by a distance corresponding to the diameter of the outer surface below the thread of the preform 10. The rollers are rotated as indicated by the arrows. This causes "equipped preform sets" to be deposited loose over the rollers 32 to align with the rollers 32 until the body 12 of the preform 10 falls between the rollers 32. equipped preform 25 is retained by the first surface 30a gripping. Advantageously, the first gripping surface 30a extends radially over at least 1.4 mm projecting from the body 12 of the preform 10. These two elements constitute stable mechanical references for the equipped preform assembly 25 in which the preform -bouchon 24 is in the coupled state, that is to say screwed fully until the lug 29 is supported on the rim 18. The pre-cap 24 has an outer lateral flank 33 which can comprising a second gripping surface 34 which may have various shapes illustrated in FIGS. 4, 5a, 5b, Sc. The second gripping surface may be a projecting ring running around the pre-plug 24. The cross-section of this ring may be semicircular as in the bead 34a illustrated in Figure 4. It may alternatively have surfaces 34b support upper and / or lower perpendicular to the axis 14, as shown in Figure 5a. It may also be a circular rib 34c illustrated in FIG. 5b. It may also consist of several sectors 34d discontinuous, raised and homogeneously distributed around the axis 14 in a plane perpendicular to the axis 14. Thus, whatever the shape retained, the second surface 34 gripping can serve as an axial reference to the equipped preform assembly 25 without requiring angular indexing. However, angular indexing of the equipped preform assembly is possible.

In another variant, the flank 33 may be devoid of element forming a relief in the axial direction. A gripper can be equipped with knurled jaws. Thus the pinching of the knurled jaw with the axially smooth flank ensures the axial immobilization of the preform assembly equipped with respect to the gripper. As illustrated in FIG. 6a, a first gripper 35 is equipped with two jaws 35a and bears on the first gripping surface 30a and on the surface 20 below the thread 15. A second gripper 36, equipped with two jaws 36a, takes bearing on the second surface 34, 34a, 34b, 34c, 34d of the substantially cylindrical portion 28 of the pre-cap 24. The first and second gripping tongs 35, 36 are axially offset so as to be able to act simultaneously. As illustrated in FIG. 6b, the first clamp 35 can hold the equipped preform assembly 25 along a first transport path 37. The second clamp 36 arrives in the open state along a second path 38. At the moment of transfer, the first clamp 35 opens and the second clamp 36 closes. Thus, the equipped preform element 25 can continue its path on the second trajectory 38.

As illustrated in FIG. 7, a stretch blow molding station 40 comprises a mold 41, a blowing nozzle 42 and a drawing rod 43. The preform 10 has been previously softened in an oven without heating the neck 11 and the pre-cap 24 in a similar manner to the heating of the traditional preforms. The equipped preform assembly 25 is then deposited on a bearing ring 44 placed in the upper part of a cavity 45 of the mold 41. The nozzle 42 comprises a seal 46 which presses against the bearing ring 44. During the stretch-blow molding, the rod 43 penetrates into the preform 10 softened by the passage 29a and the opening 17. The position of the preform assembly 25 fitted in the mold is ensured, for example by the first surface 30a of by the surface 20 of the preform 10 below the thread 15. After the stretch-blow molding, the preform 10 is transformed into a container 50 whose neck 11 is unchanged and always coupled with the pre-cap 24. In addition, the passage 29a is always open. After the stretch blow molding, the container 50 can be manipulated using, similarly to the preform 10, the first and / or second gripping surfaces 30a, 34. These surfaces can also be used in a filler. As illustrated in FIG. 8, the filled container 50 is then plugged by the fixing, preferably sealing, of a shutter 51 on the pre-cap 24 to form a plug 52. This leaktight attachment can be made, as illustrated, by a laser welding device which traverses the rim of the passage 29a without the need to unscrew the pre-cap 24. Thus, the pre-cap 24 has remained coupled with the neck 11, since the post-injection cooling of the preform 10 until In other words, the pre-cap 24 is a part of the stopper 52. The shutter 51 may comprise a tamper-evident element 53, which consists of a sealing member 53b to the container 50 and the a lug 53a connecting the sealing member 53b to a closing portion 51a of the shutter 51. In parallel with the fixing of the shutter 51 on the pre-cap 24, the sealing member 53b can be fixed on the container 50. This This fastening may for example be carried out by gluing or by laser welding. Alternatively, the tamper-evident element 53 can be separated from the shutter 51 and be fixed between the container 50 and the pre-cap 24. As illustrated in FIG. 8a, the plug variant comprises a pre-plug 24 which defends pre-cap 24 previously described in that it comprises a sealing lip 58 protruding from the lug 29 in the axial direction towards the thread 27 in order to bear on the outer cylindrical surface 19 of the collar 11 situated axially between the thread 15 and the rim 18 of the neck 11. The contact between the sealing lip 58 and the surface 19 is circular so as to constitute a sealing barrier. The sealing lip 58 protects the interior of the container from any contamination that may have been housed between the threads 27 and 15 during the various steps of the process before capping. Additionally or alternatively, the above variant plug the shutter 51 of the plug differs from the shutter previously described in that it comprises a sealing lip 57, extending axially inwardly of the container. The sealing lip 57 is designed to bear on an inside diameter of the opening 17 of the neck 11 of the container. The contact between the sealing lip 57 and the inside diameter of the opening 17 is circular so as to constitute another sealing barrier.

Advantageously, the pre-cap 24 may comprise longitudinal ridges 59 extending parallel to the axis 14 serving to increase the adhesion along the lateral flank 33 and helping the user of the container 50 to unscrew the cap manually. 52. When the user of the container filled with liquid wants to open the cap 52, he unscrews the cap 52 and tears the tab 53a. This makes it possible to detect a rupture of the sealing of the closure.

Claims (15)

REVENDICATIONS1. Process for forming and capping a container (50), characterized in that it comprises: a step of manufacturing an equipped preform assembly (25), during which a pre-plug (24) is coupled to a neck (11) of a preform (10) so that a passage (29a) of the pre-cap allows access to the interior of the preform (10), - a step of forming the container (50) from the preform (10), and - a plugging step using said pre-plug (24), during which the passage (29a) of the pre-plug (24) is closed. 2. Method according to claim 1, wherein the capping step is done without uncoupling the pre-plug. 3. Method according to one of the preceding claims, wherein the capping step uses a shutter (51) which is fixed sealingly to the pre-cap (24). 4. Method according to one of the preceding claims, wherein the step of manufacturing the equipped preform assembly (25) comprises an injection phase of the preform (10), the coupling of the pre-cap (24). on the neck (11) taking place during a cooling phase of the preform (10) just injected and before the forming step. The method of claim 4, further comprising a step of recovering the preform (10) during which the preform (10) is extracted from an injection mold by being held by means (21) of holding, the coupling of the pre-cap (24) on the neck (11) taking place before the holding means (21) releases the preform (10). 6. Method according to one of the preceding claims, comprising a plurality of processing steps of the preform (10) or treatment of the container (50) from the preform (10), and transport phases of the preform ( 10) or the container (50) between the different processing steps, wherein the pre-plug (24) remains permanently coupled to the preform (10) or the container (50) from the preform (10). 7. Method according to one of the preceding claims, wherein the capping step comprises a step of irreversibly fixing a tamper-proof element (53) between the pre-plug (24) and the container (10) from the preform. 8. Stopper (52) for closing an opening (17) of a neck (11) of container (50), characterized in that it comprises a pre-plug (24), a shutter (51) separate from the pre-cap, and a tamper-evident element (53), wherein the pre-cap (24) comprises coupling means (27) adapted to cooperate with a radially outer region of the neck (11) and a passage (29a). ) arranged so that the pre-cap (24) does not close the opening (17) of the neck (11), the plug (52) having a closed configuration in which the shutter (53) is fixed to the pre-cap (24) and the plug (52) is structured to seal the opening (17) of the neck. the tamper-evident element (53) being structured to detect sealing failure of the closure, when the plug (52) in the plugged condition is coupled to the neck (11) and the tamper-evident member (53). is attached to the container (50). The cap (52) of claim 8, wherein the shutter (51) comprises a sealing portion (51a), a sealing member (53b) to the container (50) and a connecting leg (53a) connecting the sealing member (53b) at the closure portion (51a) of the shutter (51), the closing portion (51a) being preferably rigid. Stopper according to one of claims 8 to 9, wherein the means (27) for coupling the pre-cap is a thread and / or wherein the pre-cap has means (59) positive external help at the manual disconnection and / or in which the pre-cap (24) is in one piece. 11. Stopper according to one of claims 8 to 10, wherein the means (27) for coupling the pre-cap corresponds to a standardized neck, the passage (29a) of the pre-cap having a diameter substantially equal to a diameter. inside said normalized collar. 12. Stopper according to one of claims 8 to 11, wherein the pre-cap (24) comprises a stop (29) complementary axial, arranged to cooperate with a rim (18) of the neck (11), the pre-cap further comprising a first gripping surface (30a) disposed at an axial end (30) of the pre-plug (24) opposite the complementary axial stop (29) and engageable with a first gripping pliers (35). . The stopper of claim 12, wherein the first gripping surface (30a) extends radially around the axis (14) and / or at a radial distance of at least 1.4 mm. 14. Stopper according to claim 12 or 13, wherein the pre-cap (24) has an outer sidewall (33) having a second surface (34) for gripping, adapted to cooperate with a second gripper (36) gripping simultaneously with the cooperation of the first gripper (35). 15. Stopper according to one of claims 8 to 14, wherein the pre-cap comprises at least one sealing lip (58) cooperating with a neck sealing zone (11), which zone of sealing is located on an inner side, outer (19) or upper side of the rim, and / or wherein the shutter (51) comprises at least one sealing lip (57), for example a sealing lip which cooperates with an inside diameter of the opening (17) of the neck (11).