PRODUCTS

The present invention relates to the production of containers for storing and dispensing products, in particular cosmetic products.

The invention relates more particularly to the production of a preform for flexible containers having a plurality of compartments intended to contain different products.

The expression "cosmetic product" is understood to mean any product as defined in Regulation (EC) No 1223/2009 of the European Parliament and Council of 30 November 2009 relating to cosmetic products.

Specifically, there is a need for multi-compartment containers capable of separately storing different products and allowing them to be mixed during application, while avoiding cross-contamination by limiting the migration of the products from one compartment to the other. For example, the products may have antagonistic properties and cannot generally be packaged in the mixed state. Although these products can be mixed to obtain the required result, said products react chemically to form a composition that is unstable over time, and so it is not possible to keep them simultaneously in one and the same compartment. It is for this reason that it is generally desirable to keep them in multi-compartment containers and to mix them extemporaneously.

In the prior art there are multi-compartment containers for storing and dispensing products, said containers having a body provided on the inside with a separating partition which bounds two chambers in the body, said chambers each being intended to be filled with a product.

In this regard, reference could be made to documents WO9746463, FR2627463, US5954234 and US18941 15. The container described in these documents is provided with an internal partition and has a first end forming a neck that serves for dispensing the products, and an open opposite end, through which the container can be filled, this end being intended to be closed by pinching and welding after the container has been filled. Reference could also be made to document US5849241 , which describes a method for producing a tube provided with an internal partition and formed by injection blow-moulding of a plastics material. The internal partition is deformed after moulding so as to increase its size in order to reduce its rigidity and to allow one of the openings in the tube to be closed by pinching and welding as was described above.

Another technique for producing multi-compartment containers consists in injection-moulding a plastics material in the cavity of a mould so as to form the body of the container and the internal partition in one piece. The containers are thus often produced from polypropylene, a mixture of polypropylenes, and/or of polyethylene, in particular a mixture of high and low density polyethylenes, in order particularly to be able to be compatible with the compositions or formulations likely to be contained in the compartments, to be able to be injection-moulded easily and for the container to be able to be weldable to itself.

In any case, the filling end is welded transversely in the same plane as that in which the internal partition extends, that is to say that the ovoid section of the container is pinched such that the internal partition is located in the greatest length of the pinching so as to be welded along the entire length of the end of the container. A drawback of this type of container is that when it displayed face on, that is to say with its largest dimension visible, as is the case on shop shelves, only one compartment is visible and the user cannot see that the container contains a second product. In addition, when this container is used, the user places his fingers on each face having the largest dimension and exerts a pressure simultaneously on the two compartments, as a result of which the two products are dispensed together without there being the possibility of one produced being metered with respect to the other.

Also known, from document W09929572, is a preform having a peripheral wall and an internal partition, the welding plane of which is different from the plane along which the partition extends. However, the section of the partition is S-shaped with two opposite concavities, and the welding includes, in addition to the layers of the peripheral wall, at least three layers of internal partition, thus making this welding more complex to carry out and less aesthetically pleasing on account of this overthickness.

The object of the present invention is thus to provide a flexible multicompartment container which is produced in an improved manner in order to alleviate the abovementioned drawbacks.

To this end, the invention provides a preform for a multi-compartment container for storing and dispensing products, the preform comprising a main body extending mainly along a longitudinal axis X-X and comprising a tubular peripheral wall and an internal partition, said peripheral wall and said internal partition being produced from flexible material, a dispensing head mounted on a first end of the main body and having at least two dispensing ducts, each opening at one end into a compartment and at the other end towards the outside of the device, the second, open end for filling the device being intended to be closed by pinching and welding of the edge of the peripheral wall in a welding plane.

According to the invention, the internal partition extends between the two ends mainly substantially in a plane perpendicular to the welding plane in order to bound compartments intended to contain respective products, said partition having a single, substantially symmetrical concavity along the welding plane.

According to further features of the invention, the length of the internal partition measured between two junctions with the peripheral wall in a cross section of the preform may be less than half the perimeter of the peripheral wall.

The section of the peripheral wall may be oval, and the largest dimension of this section may be in the welding plane.

The junctions between the internal partition and the peripheral wall may be positioned in a manner set back from the mid-plane perpendicular to the welding plane and including the longitudinal axis X-X.

The internal partition and the peripheral wall may be produced from transparent and/or translucent materials. The dispensing head may have a single closure cap for closing off all the dispensing ducts.

The dispensing head may have a plurality of independent closure caps, each one for closing off one dispensing duct.

The invention also relates to a container produced from such a preform, each compartment of the container then containing a different product, and the second end of the preform being closed.

The invention also relates to a method for producing such a preform, the method including a step of injection-moulding a plastics material in a cavity of a mould in order to form the main body, the peripheral wall and the internal partition then being formed in one piece.

The dispensing head may be overmoulded on the main body.

The invention finally relates to a method for producing a container from such a preform, the method comprising a step of filling the compartments in the preform, then a step of folding the open end along the welding plane, the internal partition being folded in two, then a step of welding the open end.

The welded edge of the main body may have at least one part having two portions of the internal partition that are welded together and are each welded to a portion of the peripheral wall such that the two portions of the internal partition are positioned between two portions of the peripheral wall.

The invention will be understood better from reading the following description of non-limiting examples of the implementation thereof with reference to the appended drawings, in which:

- Figure 1 shows an example of a preform for a device for applying a product according to the invention;

- Figure 2 shows a closed container filled with products and formed from the preform in Figure 1 ;

- Figure 3 is a cross section along the axis Ill-Ill in Figure 1 ; - Figure 4 is a cross section along the axis IV-IV in Figure 2;

- Figure 5 is a cross section along the axis V-V in Figure 2; - Figures 6 and 7 show variants of the closure cap of the device in

Figure 2.

With reference to the figures, in particular to Figure 2, a container 1 has two compartments 3 and 4, each containing a product P1 , P2, for example a cosmetic product such as a makeup or care product. The two products are thus kept separately and are intended to be mixed extemporaneously during application.

This container 1 is obtained from a preform 10 shown in Figure 1 . This preform 10 of the final container 1 has a main body 12 comprising a tubular peripheral wall 14 and an internal partition 16.

The tubular peripheral wall 14 extends mainly along a longitudinal axis X-X forming the longitudinal axis of the preform 10 and then of the container 1 . The cross section of this peripheral wall 14 is preferably oval, but it could also be circular or some other shape. The tubular peripheral wall 14 has a first end 18 and a second end 20.

The internal partition 16 extends in the body 12, that is to say inside the tubular wall 14, from the first end 18 to the second end 20. The partition 16 is attached to the peripheral wall 14 at two opposite portions 14a, 14b of the wall 14. Each attachment of the partition 16 to a portion 14a or 14b of the wall 14 may be substantially parallel to the longitudinal axis X-X.

In the initial preform 10, the partition 16 extends substantially along a mid-plane M-M including the longitudinal axis X-X and perpendicular to a transverse axis Y-Y of the preform 10. The transverse axis Y-Y is advantageously the axis having the largest dimension of the oval section of the tubular wall 14. Thus, in the body 12, the partition 16 bounds a first compartment 3, which is intended to be filled with a first product P1 , and a separate second compartment 4, which is intended to be filled with a second product P2.

The partition 16 does not have to be included in the mid-plane M-M but may be slightly offset from this plane such that the two compartments 3 and 4 are not symmetrical to one another with respect to the partition 16 of the preform 10. It is possible for the partition 16 not to be planar but to have a concavity facing towards one of the compartments, or to be undulating. Advantageously, the partition 16 has a single concavity oriented towards one of the compartments along the transverse axis Y-Y such that the partition 16 is symmetrical with respect to the plane containing the transverse axis Y-Y and the longitudinal axis X-X. The preform 10 may have cross sections of the body 12 that are identical over the entire length of the longitudinal axis X-X.

In any cross section of the body 12 of the preform 10, for example the one shown in Figure 3, the partition 16 has a length much less than half the perimeter of the peripheral wall 14 between two points of attachment to the peripheral wall 14. It is thus possible for the preform 10 not to be folded along the mid-axis M-M.

This length of the internal partition 16 is advantageously greater than the length of the smallest diameter of the oval peripheral wall 14 in order that the partition does not extend in a plane between the first end 18 and the second end 20 but has a concavity as defined above.

The peripheral wall 14 and the internal partition 16 are produced from one and the same flexible, that is to say pliable, material, for example thermoplastic material such as polypropylene or polyethylene. Moreover, the thickness of the wall 14 and that of the partition 16 may be between 0.1 mm and 1 mm, for example around 0.2 mm, such a thinness making it possible to produce a wall 14 and a partition 16 having optimum flexibility. Furthermore, the wall 14 and/or the partition 16 have a substantially constant thickness over the entire surface.

The internal partition 16 may also be produced from a flexible material different from the flexible material of which the peripheral wall 14 is made, for example by overmoulding the peripheral wall 14 over the internal partition 16. Advantageously, the peripheral wall 14 is produced from a transparent or translucent material, in order that the products contained in the compartments are visible from outside the container 1 .

The preform 10 also has a dispensing head 22 mounted on the first end 18 of the main body 12. This dispensing head 22 closes the first end 18 while having at least two dispensing ducts 23, 24, each opening at one end into a compartment 3, 4 and at the other end towards the outside of the device.

The dispensing head 22 may be fixed to the body 12 by any appropriate means, for example by adhesive bonding, welding, overmoulding or screwing. In the case of overmoulding or welding, the material of the dispensing head 22 must be compatible with that of the body 12.

The dispensing ducts 23, 24 may have equal dimensions, for example have the same diameter in the case of cylindrical ducts. These dispensing ducts 23, 24 may also have different dimensions, for example have sections having different shapes and/or sizes, in order that each is suitable for dispensing its respective product, for example if the viscosity of each product P1 , P2 is different.

A cap 26 is connected to the dispensing head 22. The cap 26 may be produced in one piece with the dispensing head, as in Figures 1 , 2, 5 and 6, but may also be an attached component in variants that are not shown.

When the cap 26 is produced in one piece with the dispensing head 22, it is attached to the latter by a bridge of material 27 which is thin enough to be flexible. This bridge of material 27 is generally known as a film hinge. In Figures 1 and 2, the film hinge allows the cap 26 to pivot with respect to the dispensing head 22 about an axis parallel to the transverse axis Y-Y, whereas in the variant shown in Figure 6, the film hinge allows the cap 26 to pivot with respect to the dispensing head 22 about an axis perpendicular to the transverse axis Y-Y. Any other pivot axis is also conceivable.

The bottom of the cap 26 is provided with pins 28 which are intended to close off the ducts 23 and 24 in the dispensing head 22 when the cap 26 is in the closed position. The pins 28 accordingly have a cross section which corresponds to that of their respective duct 23, 24.

In the variant shown in Figure 7, two caps 26' and 26" are connected to the dispensing head 22, each one having its own film hinge 27. Each cap 26', 26" is intended to close one orifice 23, 24. Thus, the user can selectively open one of the caps 26', 26" or both caps 26', 26" simultaneously depending on whether he wishes to dispense only the first product P1 or only the second product P2 or both products P1 and P2.

The second end 20, opposite the dispensing head 22, of the body 12 of the preform 10 is open so that the preform 10 can be filled with product, but is intended to be closed by pinching and welding after filling so that a closed container 1 as shown in Figure 2 is obtained.

In order to allow this closure, the material of the partition 16 and that of the peripheral wall 14 are compatible for hot welding, for example the material of the partition 16 and that of the peripheral wall 14 may each comprise polypropylene or polyethylene.

According to the invention, the second end 20 of the body 12 is pinched and welded in a plane containing the transverse axis Y-Y and the longitudinal axis X-X, that is to say perpendicular to the mid-plane M-M. Thus, when the section of the body 12 is oval, pinching and welding take place advantageously in the plane containing the largest dimension of this oval section, while the partition 16 extends substantially in a plane perpendicular to this plane containing the largest dimension of this oval section. Consequently, the internal partition 16 is folded in at least two parts so that two opposite edges of the peripheral wall can be brought together for welding. The initial concavity in the partition 16 of the preform promotes this folding in two of the partition 16. In the welding zone, the pinched partition 16 thus adopts a U-shaped configuration, as is shown in Figure 4.

As can be seen in Figure 4, the welded second end 20 of the main body 12 thus has at least one part 30 having two portions 16a, 16b of the internal partition 16 welded together and each welded to a portion 14a, 14b of the peripheral wall 14 such that the two portions 16a, 16b of the internal partition 16 are positioned between two portions 14a, 14b of the peripheral wall 14. The welded second end 20 of the main body 12 may also have at least one part 31 , 32 having two portions 14a, 14b of the peripheral wall 14 that are welded directly to one another.

With this type of pinching and welding, the radius of the concavity in the partition 16 thus varies along the axis X-X, the radius increasing from the second end to the first end of the body 12, this being visible in Figures 4 and 5, which show cross sections at different points along the longitudinal axis X-X.

As was described above, the partition 16 is advantageously slightly offset from the mid-plane M-M. Specifically, after the filling of the two products P1 , P2, the welding, in the plane of the major axis of the section of the body 12, closes the concave partition 16 on itself, the concave partition 16 extending more into one compartment 4 than into the other compartment 3. As can be seen in Figures 3 and 5, the initial offset D with respect to the mid-plane M-M towards the compartment which is opposite the one into which the concave partition 16 extends the most makes it possible to obtain two compartments 3, 4 having substantially identical volumes, in that the advancement of the partition 16 into one compartment 4 is compensated by the initial offset D of the edges attaching the partition 16 to the wall 14 towards the other compartment 3.

A method for obtaining the preform 10 and then the container 1 of the invention will now be described.

In order to manufacture the preform 10, it is necessary first of all to injection-mould a plastics material in the cavity of a mould, thereby forming the body 12 with its peripheral wall 14 and its internal partition 16 in one piece. Following partial modification of the mould at the first end of the body 12, a second injection-moulding operation of a material compatible with the first is carried out in order to overmould the dispensing head 22, which is hot-welded automatically to the body 12 which has already been injection-moulded. The cap 26 can also be injection-moulded together with the dispensing head 22 so as to be in one piece with this head 22, the link between the cap 26 and the dispensing head 22 being formed by a film hinge. The preform formed in this way is then removed from the mould.

A packaging phase then takes place. To this end, the cap 26 is closed such that the dispensing ducts 23 and 24 are closed off, and each preform 10 is transferred to a filling station, where the preform 10 is filled through its open second end 20 opposite the dispensing head 22 closed by way of its cap 26. The two compartments 3 and 4 can be filled with two different products P1 , P2 which are intended for example to be mixed extemporaneously during application. Provision is made to leave an upper part close to the second end 20 without formulations so that this part is almost filled during the deformation of the preform by pinching, which tends to reduce the volumes of the compartments 3 and 4 during closure.

To this end, the open end 20 of the filled preform 10 is presented to a heat source, for example infrared rays, hot air or else hot contact. Advantageously, the heat source is a source of hot air which outputs a directed flow of air towards the material of the preform 10 and not towards the products P1 , P2 so that the latter are not deteriorated by the heat.

When the plastics material has reached a temperature threshold suitable for it to be welded, the open second end 20 is pinched tightly between two mechanical jaws so as to weld it. The second end 20 closed in this way is then cooled by any appropriate means, for example in a tunnel of cold air. The container shown in Figure 2 is thus obtained.

As mentioned above and as is shown in Figure 4, on travelling along the axis Y-Y, the welded second end 20 has a part 31 having two thicknesses, followed by a part 30 having four thicknesses, followed by another part 32 having two thicknesses, it therefore being possible for the form of the pinching jaws to be adapted to this profile for welding.

The invention is not limited to the examples illustrated, in particular although in the exemplary embodiment envisaged the container is provided with only a single separating partition, it would also be possible, as an alternative, to provide the container with a plurality of partitions so as to form a greater number of compartments in the container in order to store a greater number of products. The expression "comprising a" should be understood as meaning "comprising at least one", unless specified to the contrary.