FR2902040A1 - Fabricating a container in plastic material useful in a field of cosmetics and food, comprises making a first preform by injection, and conferring part of final form of the container to be manufactured on the preform by blow-drawing - Google Patents

Abstract

The process of fabricating a container in plastic material useful in a field of cosmetics and food, comprises making a first preform by injection, and conferring part of final form of the container to be manufactured on the preform by blow-drawing, which induces the production of extension of a thick zone inherent to a migration of part of the material constituting the preform. The preform is fitted with an extension stretching according to a direction perpendicular to its main dimension and its vicinity of its upper zone intended to serve as neck (4). The process of fabricating a container in plastic material useful in a field of cosmetics and food, comprises making a first preform by injection, and conferring part of final form of the container to be manufactured on the preform by blow-drawing, which induces the production of extension of a thick zone inherent to a migration of part of the material constituting the preform. The preform is fitted with an extension stretching according to a direction perpendicular to its main dimension and its vicinity of its upper zone intended to serve as neck (4) so that at the stage of blow-drawing, the manufacturing of increased thick zones intervene in upper and lower zones of the container. A constitutive material of the preform is a rigid thermoplastic. The preform comprises extension at its upper zone so that during blow-drawing operation, the extra thickness inherent to the migration of the constitutive material intervenes only at the upper zone to have a certain rigidity. The other end of the preform is devoid of extension. The material chosen for the preform has a flexibility for allowing its cutting and its narrowing after blow-drawing. The lower end of the preform thus narrowed is welded to obtain a proper tube, where the welding is carried out before or after filling the tube. A flexible thermoplastic material is constitutive of the preform.

Description

PROCESS FOR MAKING A PLASTIC CONTAINER AND CONTAINER

OBTAINED WITH SUCH A METHOD

  FIELD OF THE INVENTION The invention relates to a method for producing a plastic container having a single wall. This container may further consist of a flexible wall tube of the type that is encountered in the cosmetic field, even food. The invention uses so-called injection-blow molding technology, also known as stretch-blow molding.

  PRIOR ART Plastic containers are nowadays widely known, whatever their destination, namely cosmetic, food or other.

  They can be made of any material, and are traditionally made by blowing, injection-blowing, etc.

  However, in a number of applications, including cosmetics, it may be desired to give the container a particular aesthetic appearance, such as for example that of a bottle made of glass. Other types of bottles are constituted by a tube, that is to say by a container whose end intended to allow the flow of the contents, is substantially rigid in order to be closable by a lid, and the other end is pinched and welded to form the tube itself, the walls of the tube being relatively flexible to allow the user to simply release the contents of the user's hand.

  The production of such tubes, nowadays widely used, first of all requires the manufacture of the upper end of the tube, acting as an outlet collar 35 of the contents and then the fastening of this upper end to the walls. flexible of a tube itself, of generally cylindrical shape, before its clamping and closure by welding after filling.

  In other words the realization of such a tube requires several steps using different constituents and materials and important equipment.

  In addition, the possibilities of various forms are reduced.

  The invention also aims to simplify this method of production.

  SUMMARY OF THE INVENTION The object of the invention is therefore to provide a process for producing a plastic container which consists of: firstly, making a first preform by injection, said preform being provided with an extension in one direction; substantially perpendicular to its main dimension, at least in the vicinity of its upper zone intended to act as a neck; and to give this preform by stretch-blow molding at least part of the final shape of the container to be produced, this stretch-blow molding step inducing the realization at the level of said extension of a zone of greater thickness, inherent to migration of part of the material constituting said preform.

  According to a first embodiment of the invention, the preform in question also has an extension at its lower end, also extending in a direction substantially perpendicular to its main dimension, so that, when stretch-blow step, the realization of areas of increased thickness occurs in the upper and lower area of the container.

  Thus, by this particular method, a bottle is obtained, and in a general manner a container, the external appearance of which is similar to that of the glass, because of the respective lower and upper thicknesses with which it is provided. Such an appearance is particularly sought after in the field of cosmetics.

  Of course, the extensions of which the preform is provided may be of various shapes, depending on the definitive shape that it is desired to confer on the container.

  According to a second embodiment of the invention, the preform has an extension limitatively at its upper zone, so that during the stretch-blow molding operation, the extra thickness inherent in the migration of part of the material which the constitutes, intervenes at the level of this upper zone, adapted to give it a certain rigidity, sought to allow in particular to facilitate the establishment of a cap, a lid or other closure system.

  On the other hand, the other end is devoid of extension and the chosen material of the preform is such that it has a certain flexibility for, after stretch-blow molding, to allow the cutting of its lower end, the latter being then welded after pinching. to achieve the realization of a tube itself. The welding operation can occur before or after filling, depending on whether it intervenes by the lower end or by the neck.

  According to the invention, the flexible thermoplastic material constituting the preform is chosen from the group comprising polyolefins, ADFLEX (a special polyolefin resin catalloy), thermoplastic elastomers based on styrene, polyurethane, PVC or any other material flexible and compatible.

  The manner in which the invention can be realized and the advantages which result therefrom will emerge more clearly from the exemplary embodiments which follow, given by way of indication and not by way of limitation, in support of the appended figures.

  BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a diagrammatic perspective view of a bottle according to a first embodiment of the invention, having the illusion of being made of glass, or with a top and a solid bottom. FIGS. 2a to 2c schematically illustrate the different steps in the embodiment of the bottle shown in FIG. 1, each of said figures having three views, a view from above, and two lateral views oriented at 90 relative to one another. other. Figure 3 is a schematic representation of a plastic tube obtained according to a second embodiment of the invention. FIGS. 4a to 4c are diagrammatic representations illustrating the various steps of making the tube of FIG. 3, each having a top view and two side views oriented at 90 relative to one another.

  DETAILED DESCRIPTION OF THE INVENTION

  FIG. 1 thus illustrates a bottle (1) made of plastic, which can be observed that the base or bottom (2) on the one hand, and the upper part (3) from which emerges the collar (4) from other on the other hand, have an extra thickness. This may be relatively large compared to the thickness of the side walls of said bottle.

  In doing so, this bottle has an aesthetic appearance that may suggest that it is glass without, however, the disadvantages, particularly in terms of implementation 10 on the one hand and in terms of fragility on the other.

  To make such a bottle and in accordance with Figures 2a to 2c, it proceeds first (Figure 2a) to the embodiment, by injection, a preform (6) for example made of PET. This preform (6) conventionally has a symmetry along two perpendicular planes of symmetry I and II, as schematized in the view from above. This preform (6) is provided, according to a feature of the invention, with an upper extension (7) and a lower extension (8), also issuing from injection, and therefore made of the same material as the rest of the preform.

  These two extensions each extend in a direction substantially perpendicular to the main dimension of the preform. In this case, the preform (6) is mainly vertical, and the extensions (6, 7) are horizontal.

  Beyond the upper extension (7), there can be observed a particular zone for defmir the neck (4) of the container. The outer peripheral wall of said neck is provided with a thread or a latching means (5), intended to cooperate with a cap, a lid or any other closure system.

  In the next step (Figure 2b), the preform (6) undergoes a stretch-blow phase in a mold (9) of suitable shape, to give the preform the final shape of the container. The result of this stretch-blow phase is visible in FIG. 2c. It is thus observed that, due to the extensions (7, 8) of which the preform (6) is provided, during the stretch-blow molding step, there is a partial migration of the material constituting said preform to the contact respectively of the upper extension (7) (under this one) and the lower extension (8) (on this one).

  This migration thus gives the bottom (2) and the upper zone (3) of the container an extra thickness, giving the illusion of glass.

  For this purpose the constituent thermoplastic material of the preform is advantageously transparent or translucent. In addition to PET, any rigid thermoplastic material may be envisaged, and in particular PET copolymer, PCTA, copolyesters, an ionomer, polysulfone-PS, SAN (Styrene Acrylo Nitrile), a copolymer of acrylonitrile-methyl acrylate, polypropylene, polyethylene and PVC.

  According to another embodiment of the invention illustrated in connection with FIGS. 3 and 4, a tube (10) is produced, that is to say a container provided at one of its ends. a substantially rigid zone (11), extended by a collar (12), provided with an external thread (12), intended to cooperate with a cap or lid or any other closure system, and the rest of which consists of a substantially flexible wall (13), to allow by manual pressure of the user to obtain the evacuation of the desired amount of the content stored or stored in such a tube, this wall (13) being pinched and welded to its end (14).

  For this purpose, there is also a preform (15), this time provided with an upper extension (16), and no longer upper and lower as in the previous case. This preform again has a symmetry along two perpendicular planes of symmetry I and II, as can be seen in the top views of FIGS.

  On the other hand, the remainder of the preform has substantially a symmetry of revolution. FIG. 4a shows the walls (17) of the mold in which said preform is intended to expand during the stretch-blow molding operation.

  Thus, during this step, the preform will fit the walls of the mold and corollary, like the previous embodiment, there will be migration of a portion of the material constituting the preform at the upper extension (16), and especially under it, so as to impart an extra thickness at this level and especially, in the context of this embodiment, a certain rigidity at this area (11).

  Indeed, the preform is, in this particular case, made of a flexible thermoplastic material. It is conceivable that with such a flexible material and in the absence of the method of the invention, the upper zone of the tube, that is to say close to the neck (12), would be unsuitable to allow a coherent closure and sealed by any shutter system. On the other hand, because of the extra thickness obtained during the stretch-blow molding stage and inherent to the production of a preform provided with an upper extension, this zone is given sufficient rigidity to achieve the required result.

  The remainder of the container obtained has flexible walls, whose end can be cut and pinched, and finally welded (Figure 3d) to obtain a conventional tube. This welding occurs before or after the filling of the tube thus produced, depending on its filling mode. The flexible material used may be of different types and in particular chosen from the group comprising polyolefins, ADFLEX (a special polyolefin resin catalloy), thermoplastic elastomers based on styrene, polyurethane, PVC, or any other material. flexible and compatible.

It is conceivable in fact all the interest of the method according to the invention which allows by a technology today well controlled (stretch-blow molding), on the one hand, the realization of a tube without requiring the complexity of processes and equipment known to date, and on the other hand, that of a bottle with aesthetic properties, and offering a variation of shapes in its much wider upper part.

Claims (7)

  1. A method for producing a plastic container, characterized in that it consists: first of all in producing a first preform (6, 15) by injection, said preform being provided with an extension (7, 16) extending in a direction substantially perpendicular to its principal dimension, at least in the vicinity of its upper zone intended to act as a neck (4, 12); and to give this preform (6, 15) by stretch-blow molding at least part of the final shape of the container to be produced, this stretch-blow molding step inducing the realization at said extension (7, 16) of a zone of greater thickness, inherent in the migration of part of the material constituting said preform.   2. Method for producing a plastic container according to claim 1, characterized in that the preform (6) also has an extension (8) at its lower end, also extending in a direction substantially perpendicular to its dimension. main, so that, during the stretch-blow molding step, the realization of areas of increased thickness occurs in the upper and lower area of the container.   3. Process for producing a plastic container according to claim 2, characterized in that the constituent material of the preform is a rigid thermoplastic chosen from the group comprising PET, PET copolymer, PCTA, copolyesters, an ionomer , polysulfone-PS, SAN (Styrene Acrylo Nitrile), a copolymer of acrylonitrile-methyl acrylate, polypropylene, polyethylene, PVC.   4. A method for producing a plastic container according to claim 1, characterized in that the preform (15) has an extension (16) limitatively at its upper zone (11), so that during the operation of stretch-blow molding, the extra thickness inherent in the migration of part of the material that constitutes it intervenes only at the level of this upper zone, able to give it a certain rigidity.   5. A method for producing a plastic container according to claim 4, characterized in that the other end of the preform (15) is free of extension, and in that the selected material of the preform is such that has a certain flexibility for, after stretch blow molding, allow its cutting, and its nip, the lower end (14) and pinched welded to achieve the realization of a tube itself.   6. A method of making a plastic container according to claim 5, characterized in that the tube is welded before or after filling.   7. Process for producing a plastic container according to claim 5, characterized in that the flexible thermoplastic material constituting the preform is selected from the group comprising polyolefins, ADFLEX 15 (a special polyolefin resin catalloy), elastomers thermoplastics based on styrene, polyurethane and PVC.