FR3014728A1 - METHOD AND METHOD FOR PRODUCING A PREFORM AND AEROSOL FLASK, AEROSOL PREFORM AND AEROSOL FLAKE - Google Patents

Abstract

The invention relates to a method for producing a preform comprising the following steps: - providing a matrix (25) of a mold (20) defining a cavity (26), the matrix (25) defining a conduit (40) ) conveying material (15) opening into the cavity (26) through an injection orifice (41); - Arrangement of a spindle (30) in the cavity (26), one end (50) of the spindle (30) being arranged opposite the injection orifice (41); injection into the mold (20) of a first dose of fluidized material (15); - removal of the spindle (30) and injection of a second dose of material (15) fluidized; - final advanced pin (30) in the cavity (26) to bring the end (50) of the pin (30) of the injection port (41); - At least partial solidification of the fluidized material (15) and extraction of the preform from the cavity (26).

Description

The present invention relates to a method for producing a preform comprising the following steps: providing a matrix of a mold defining a preform; cavity, the die defining a material conveying conduit opening into the cavity through an injection port; - Arrangement of a pin in the cavity, an end of the pin being disposed substantially opposite the injection port; injection into the mold of a dose of fluidized material intended to solidify; final advanced pin in the cavity to bring the end of the pin to the injection port; - At least partial solidification of the fluidized material and extraction of the preform from the cavity. The invention applies to the production of a preform, in particular for the manufacture of an aerosol flask by blowing this preform. The aerosol bottle is intended to receive a cosmetic product under pressure, mixed with a propellant gas. It is intended to be closed by a distributor.

The cosmetic product is for example a hair cosmetic product, for holding the hair, a cosmetic care product, for example a deodorant or an antiperspirant. For the purposes of the present invention, the term "cosmetic product" more generally means a product as defined in Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products. In order to manufacture bottles intended to receive such products, it is known to first produce a preform with predetermined dimensions, for example by injection. The preform is then blown to reach the dimensions of the desired bottle.

It is known from US 2012/0242005 to produce an injection-compression preform in a mold of fluidized material intended to solidify. In this method, a dose of fluid plastic material is injected between a matrix and an insert of a mold, freely movable relative to the matrix, causing a recoil of the insert relative to the matrix. Then, the insert is pushed back into the die to compress and distribute the plastic.

Nevertheless, such a method is not entirely satisfactory. Indeed, this process leads to making preforms that in some cases have areas of irregular size, or areas where the material is crystallized, for example in the area facing the injection point in the mold of the material thinned.

A bottle obtained by blowing said preform is then likely to have points of weakness corresponding to the defect areas. The bottle is likely to break if a fluid under pressure is introduced. The bottle is not suitable for use as an aerosol bottle. CA 2714344 describes another injection-compression container manufacturing process. An object of the invention is to provide a method which makes it possible to obtain preforms that can be blown to obtain resistant aerosol bottles. For this purpose, the subject of the invention is a method of the aforementioned type, in which the arrangement of the spindle in the cavity comprises an initial advance of the spindle to a first position in which the end of the spindle and the spindle injection port are located axially at a first distance, and then locking the spindle in the first predetermined position during a first phase of the injection step; the method comprising, during a second phase of the injection step, and before the final step of advancing the spindle, a step of removing the spindle to move the end of the spindle away from the orifice injection, and a step of locking the spindle when said spindle reaches a second position in which the end of the spindle and the injection port are located axially at a second distance greater than the first distance. According to particular embodiments, the method according to the invention has one or more of the following characteristics, taken separately or in any technically possible combination: after the final advance of the spindle, the spindle occupies a third a position in which the end of the spindle and the injection port are located axially a third distance, the third distance being less than the second distance; the third distance is less than the first distance; the first distance is less than the third distance; the step of final advance of the spindle is preceded by a step of closing the injection orifice; the material intended to solidify which is injected through the injection orifice is made from a plastic material, in particular a thermoplastic material; the thermoplastic material is chosen from polyethylene terephthalate (PET), polyacrylonitrile (PAN), crystal polyamide, polycarbonate, their copolymers and / or their mixtures; - The injection step comprises the successive injection through the injection port of a first material intended to solidify and a second material intended to solidify, different from the first material. The invention also relates to a preform that can be made by the method as described above. According to another advantageous aspect of the invention, the preform comprises a hollow wall and a neck disposed at the end of the hollow wall, the neck being devoid of threading. The invention also relates to a method of manufacturing an aerosol bottle comprising the following steps: - providing a preform obtainable by the method as described above; inserting a blast gas injection member into a hollow portion of the preform; introduction of the preform into a hollow mold having a mold cavity of shape complementary to that of the aerosol bottle; - Blowing of the preform to apply it in contact with the mold and form the aerosol flask. According to another advantageous aspect of the invention, the method comprises filling the aerosol flask with a product under pressure and closing the aerosol flask to keep the product under pressure in the flask. The invention also relates to an aerosol flask that can be manufactured by the method as described above. According to another advantageous aspect of the invention, the aerosol bottle has a hollow wall and a neck without thread. The invention will be better understood with the aid of the description which will follow, given solely by way of example, and with reference to the appended drawings, in which: FIG. 1 is a detail of a view in section of FIG. a blowing machine when blowing a vial from a preform; - Figure 2 is a detail of a sectional view of a machine for producing a preform by injection-compression, in a first step of producing the preform used to blow the bottle of Figure 1; - Figure 3 is the detail of Figure 2, in a second step of producing the preform; - Figure 4 is the detail of Figure 2, in a third step of producing the preform; - Figure 5 is the detail of Figure 2, in a variant of the second step of producing the preform; and FIG. 6 is the detail of FIG. 2, during the third step of producing the successive preform in the step of FIG. 5. A first bottle 2 according to the invention is visible in FIG. its manufacture. This bottle 2 is made by blowing a preform 5, visible in Figure 4. Advantageously, the bottle 2 is an aerosol flask. The bottle 2 has a side wall 6 and a neck 7. It defines an interior volume 8 for receiving a cosmetic product under pressure, optionally mixed with a propellant. The interior volume is for example between 15 cm3 and 220 cm3. The pressure of the cosmetic product present in the internal volume 8 is for example greater than 1 bar and especially between 1.6 bar and 8 bar at 20 ° C.

The bottle 2 is closed by a closure and dispensing member (not shown), intended to selectively confine the cosmetic product in the bottle 2. At a distance from the neck 7, the side wall 6 has a substantially constant thickness. This average thickness is less than 3 mm. In this example, the neck 7 comprises a flange 9 which protrudes externally for fixing the closure member and distribution. The neck is thus devoid of external thread, which facilitates its demolding. The bottle 2 is blown from the preform 5 into a blow mold 11 visible in FIG. 1. The blow mold 11 comprises a hollow wall 12 delimiting a mold cavity 13 of shape complementary to that of the bottle 2, and a blast gas injection member 14 protruding into the cavity to be introduced into the preform 5. Referring to FIG. 4, the preform 5 is made of a material 15. Preferably, the material 15 is a plastic material, advantageously a thermoplastic material, for example a thermoplastic material chosen from polyethylene terephthalate (PET), polyacrylonitrile (PAN), polycarbonate (PC), transparent polyamide, their copolymers and / or their mixtures. The material 15 advantageously has a crystal appearance, that is to say that it is transparent in the field of visible light. The preform 5 has an elongated shape along a longitudinal axis X-X. It comprises a side wall 16 of thickness greater than the thickness of the side wall 6 of the bottle 2 is a hollow central portion 17.

The thickness of the side wall 16 of the preform 5 is for example between 1 mm and 4 mm. In this example, the preform 5 has a rounded bottom 18. It further comprises an end flange 19 intended to form the flange of the flask 2. In FIG. 4, the preform 5 is illustrated at the end of its manufacture by injection-compression in a mold 20. The mold 20 comprises a hollow die 25 delimiting a molding cavity 26 and a pin 30 intended to be introduced into the molding cavity 26, to delimit a cavity 31 of shape complementary to that of the preform 5. It further comprises a control assembly (not shown ) of the position of the pin 30 in the molding cavity 26. The die 25 defines a conduit 40 for conveying material into the cavity 26. The conduit 40 for the flow of material opens into the cavity 26 via a hole 41 of 'injection. The conduit 40 is provided with a selectively closing member 42 of the injection orifice 41, making it possible to isolate the molding cavity 26 from the conveying conduit 40. The pin 30 extends along the longitudinal axis XX. During the manufacture of the preform 5, the spindle 30 is disposed in the cavity 26, a free end 50 of the spindle 30 being substantially disposed opposite the injection orifice 41. Advantageously, the conduit 40 has at least one end section 51 coaxial with the longitudinal axis XX of the pin 30 and opening through the injection port 41. As will be seen below, the pin 30 is movable in the cavity 26 along the axis XX, through the control assembly, between a first initial position advanced fluid injection, visible in Figure 2, a second position back end injection, visible in FIG. 3, and a third advanced end position of compression of the fluid, visible in FIG. 4. The driving assembly is able to move the pin 30 between each of the preceding positions, and also, to immobilize the pin 30 in each previous positions. A method of making the preform 5 will now be described. In a first step of the method, the spindle 30 is advanced in the cavity 26 to the first position in which the end 50 of the spindle 30 and the injection orifice 41 are located axially along XX at a first D1 distance, as shown in Figure 2. The pin 30 is then locked in the first position, for example for a first predefined period of time T1, especially between 0.2 s and 2 s. The closure member 42 is open to put in fluidic communication the duct 40 and the molding cavity 26.

Then a first dose of fluidized material is injected into the mold 20, through the conduit 40 and the orifice 41. The fluidized material abuts against the end 50 of the pin 30 and is distributed around the pin 30 in the cavity 26. The first distance D1 is for example between 0.4 mm and 3 mm.

In a second step, the pin 30 is first unlocked. A second dose of fluidized material is injected into the mold 20, causing the pin 30 to retract. In another embodiment, the control assembly causes the pin 30 to retract during the second step.

According to the invention, pin 30 is again blocked when it reaches the second retracted position. In this position, the end 50 of the spindle 30 and the injection orifice 41 are located axially along XX at a second distance D2, greater than the first distance D1, as illustrated in FIG. 3. Locking the spindle 30 is maintained for a second predefined period of time T2, in particular between 0.1 s and 2 s. The retraction and locking of the spindle 30 in the second position allows a better distribution of the fluidized material in the cavity 26 and prevent the crystallization of the material in the zone situated opposite the injection orifice 41, between the end 50 of the pin 30 and the injection port 41.

Once the second dose of fluidized material is injected, the injection orifice 45 is advantageously closed off by the closure member 42. Alternatively, as illustrated by FIGS. 5 and 6, during the second step, a dose of a fluidized intermediate material, different from the material 15, is injected into the mold 20, replacing the second dose of fluidized material.

Preferably, the material 53 is a plastic material, advantageously a thermoplastic material, for example a thermoplastic material chosen from polyethylene terephthalate (PET), polyacrylonitrile (PAN), polycarbonate (PC), transparent polyamide, and copolymers thereof. and / or their mixtures. The portion of the material in contact with the hollow matrix 25 forms a partially solidified outer skin 55. The portion of the material 15 in contact with the pin 30 forms an inner film 57 partially solidified.

During the injection, the fluidized intermediate material is spread between the outer film 55 and the inner film 57 around the spindle 30. Advantageously, once the dose of fluidized intermediate material 53 has been injected, a fluidized material sealing dose is injected through the injection port 45.

The sealing dose ensures the continuity of the outer film 55 in material 15 at the injection port 45, as shown in FIG. 6. Preferably, the injection port 45 is then closed by the shutter member 42. In a third step, the spindle 30 is advanced into the cavity 26 to the third position. In this position, the end 50 of the spindle 30 and the injection orifice 41 are located axially along XX at a third distance D3, as illustrated in FIG. 4, to form the preform 5. Advantageously, the third distance D3 is smaller than the second distance D2 and is greater than the first distance D1.

This makes it possible to homogenize the stresses applied to the material during compression. The side wall 16 of the preform 5 is thus homogeneous, both in terms of thickness and applied stresses. After at least partial solidification of the fluidized material, the preform 5 is extracted out of the cavity 26.

The preform 5 thus obtained has few areas where the material is crystallized compared to the preforms usually obtained by injection-compression. Indeed, during a conventional injection phase, the pressure exerted at the injection point tends to include the still fluid material in the partially solidified material, which causes a local lack of homogeneity and tensions in the material. With the injection-compression method according to the invention, the pressure is distributed over the entire surface of the free end 50 of the spindle 30 with a distribution of stresses in the material. The preform 5 is then used to make a bottle 2, for example an aerosol flask. The preform 5 is introduced into a mold 11 for bottle 2 having a mold cavity 13 of complementary shape to that of the bottle 2. The blowing gas injection member 14 is inserted into the hollow portion 17 of the preform 5.

A blowing gas under pressure and introduced into the preform 5 to deform the side wall 16, reduce its thickness, and apply it in contact with the mold 11. The side wall 6 of the bottle 2 is thus defined, with a substantially constant thickness, and an absence of defect zone, particularly in the bottom of the flask. At least one cosmetic product, advantageously under pressure, is then introduced into the bottle 2. The bottle is then closed by the closure and dispensing member. According to a particular embodiment, the mold 11 for bottle 2 is configured so that the bottle 2 obtained by blowing the preform 5 comprises a neck 7 without threading, as shown in FIG. 1. According to a particular mode of implementation, process of producing the bottle 2, a single machine allows the production of the preform 5 and the bottle 2. The containers made according to the method according to the invention have, compared to the containers made according to the method of the state of the technical, better resistance to regulated drop tests (see Directive of 20 May 1975, paragraph 4.1.2). These tests are conducted according to the adapted protocol described below.

The protocol includes a series of non-pressurized tests and two sets of pressurized tests. During the series of non-pressurized tests, ten containers are filled with a volume of water equal to 85% (± 0.5 g mass) of their volume brimming. A valve is then crimped onto the neck of each container.

Subsequently, five vertical receptacles and five horizontal receptacles falling from a height of 1.80 m were dumped onto concrete floors, in accordance with the Directive of 20 May 1975, paragraph 4.1.2. The test is considered successful if no breakage resulting in a leak is observed, the pressurized tests can then be conducted.

The purpose of the pressurized tests is to verify the behavior of the containers undergoing storage in extreme environments. During the pressurized tests, fifty containers are provided. The containers are filled with a volume of water equal to 85% (± 0.5 g mass) of their volume brimming.

A valve is then crimped onto the neck of each container. The containers are pressurized to 8 bar (± 0.3 bar) of nitrogen or compressed air. Of these containers, twenty-five are placed in a bath at 55 ° C (± 2 ° C) for at least six hours. The other twenty-five containers are placed in a freezer at 18 ° C (± 2 ° C) for at least twenty-four hours.

The containers thus prepared are then released, within five minutes after leaving the corresponding climatic environment, half vertically and half horizontally, a height of 1.80 m on a concrete floor, in accordance with Directive of May 20, 1975, section 4.1.2. For each series of pressurized tests, a defect is critical if there is a breakage or cracking causing leakage of the container (leakage or breakage of the valve is not unacceptable). If the container is equipped with accessories such as a bottom, its deterioration or disconnection of the container during the test will be notified but will not be taken into account for the issuance of the technical approval. Other tests may be carried out as an expert appraisal to better understand the material but do not enter into the technical approval. By way of example, mention may be made of: second and third drops, pressurized fall at room temperature, at 5 ° C., at -18 ° C. with waiting for the samples to return to ambient temperature, etc.

Claims (14)

CLAIMS 1.- A method of producing a preform (5) comprising the following steps: - providing a matrix (25) of a mold (20) defining a cavity (26), the matrix (25) defining a conduit ( 40) for conveying material (15, 53) opening into the cavity (26) via an injection orifice (41); - Arrangement of a spindle (30) in the cavity (26), one end (50) of the spindle (30) being arranged substantially opposite the injection orifice (41); - injection into the mold (20) of a dose of material (15, 53) fluidized to solidify - final advanced pin (30) in the cavity (26) to bring the end (50) of the spindle (30) the injection port (41); at least partial solidification of the fluidized material (15, 53) and extraction of the preform (5) from the cavity (26); wherein the arrangement of the pin (30) in the cavity (26) comprises an initial advance of the pin (30) to a first position in which the end (50) of the pin (30) and the orifice (41) are located axially at a first distance (D1), then locking the spindle (30) in the first predetermined position during a first phase of the injection step; the method comprising, during a second phase of the injection step, and before the final step of advancing the spindle (30), a step of removing the spindle (30) to move the end ( 50) of the spindle (30) of the injection port (41), then a step of locking the spindle (30) when said spindle (30) reaches a second position in which the end (50) of the pin (30) and the injection port (41) are located axially at a second distance (D2) greater than the first distance (D1). 2.- Method according to claim 1 characterized in that after the final advance of the spindle (30), the spindle (30) occupies a third position in which the end (50) of the spindle (30) and the injection port (41) are located axially a third distance (D3), the third distance (D3) being lower than the second distance (D2). 3. A method according to claim 2, characterized in that the third distance (D3) is less than the first distance (D1). 4. A method according to claim 2, characterized in that the first distance (D1) is less than the third distance (D3). 5.- Method according to any one of the preceding claims, characterized in that the final step of advancing the spindle (30) is preceded by a step of closing the orifice (41) of injection. 6. A process according to any one of the preceding claims, characterized in that the material (15, 53) intended to solidify which is injected through the orifice (41) of injection is made from a material plastic, in particular a thermoplastic material. 7. A process according to claim 6, characterized in that the thermoplastic material is chosen from polyethylene terephthalate (PET), polyacrylonitrile (PAN), crystal polyamide, polycarbonate (PC), their copolymers and / or their mixtures. 8. A process according to any one of the preceding claims, characterized in that the injection step comprises the successive injection through the injection orifice (41) of a first material (15) intended to be solidify and a second material (53) to solidify, different from the first material (15). 9. Preform (5), characterized in that it is capable of being carried out by the method according to any one of claims 1 to 8. 10. Preform (5) according to claim 9, characterized in that it comprises a wall (16) hollow and a neck disposed at the end of the wall (16) hollow, the neck being devoid of threading. 11. A method of manufacturing an aerosol flask (2) comprising the following steps: providing a preform (5) obtainable by the method according to any one of claims 1 to 8; - insertion of a blow gas injection member (14) into a hollow portion of the preform (5); introducing the preform (5) into a hollow mold (11) having a molding cavity (13) of shape complementary to that of the aerosol bottle (2); Blowing of the preform (5) to apply it in contact with the mold (11) and forming the aerosol flask (2). 12. Method according to claim 11, characterized in that it comprises filling the aerosol bottle (2) with a product under pressure and closing the aerosol bottle (2) to maintain the product under pressure in the bottle (2). . 13.- Vial (2) aerosol characterized in that it is capable of being manufactured by the method according to any one of claims 11 or 12. 14.- Vial (2) aerosol according to claim 13 characterized in that it comprises a hollow wall (6) and a neck (7) devoid of threading.