WO2002018221A1 - Soft package with protective layer - Google Patents

Abstract

The invention concerns a component (2, 3) for a soft package (1) with a substantially tubular shape comprising a narrow neck (7, 28) at one of its ends and a flat closure at the other end, said package being designed to contain a consumable product (5), such as toothpaste, which is squeezed out by pressing with the fingers. More particularly, the invention concerns a package component comprising an anti-diffusion layer (8) designed to protect the consumable product from its environment.

Description

 FLEXIBLE PACKAGE HAVING A PROTECTIVE LAYER

The present invention relates to a component for flexible packaging of essentially tubular shape comprising a narrow neck at one of its ends and a flat closure at the other of its ends, said packaging being intended to contain a consumable product, such as a toothpaste, which comes out under the pressure of the fingers.

It relates more precisely to a packaging component which comprises an anti-diffusion layer intended in particular to protect the consumable product from its environment.

The present invention also relates to methods of placing said anti-diffusion layer.

In the present text, by “essentially tubular shape”, it is understood any hollow longitudinal object, not necessarily rectilinear, resembling approximately a cylinder but whose section can be variable over the length of the cylinder and have any shape, for circular, oval or polygonal example.

For the sake of simplification, the term "tube" will be used subsequently to mention the packaging defined above.

It should be noted that a tube according to the invention can comprise a plurality of compartments. By way of non-limiting example, mention may be made of tubes with double compartments, each compartment containing a different product, the two products only coming into contact when they are expelled from the tube.

A tube can include one or more components. Most often, there is a skirt, a head and a cap. The head has substantially the shape of a hollow truncated cone on which is located a cylinder forming the narrow neck and the external face of which can be threaded in order to receive a plug which is screwed into it. Alternatively, the outer face of the narrow neck is not threaded, the plug being fixed by simple pressure.

The skirt has a substantially tubular shape. It can be manufactured either by extrusion or by winding a laminated film.

In the case where the head is prefabricated, generally by injection, the head and the skirt are made integral with one another by welding.

Another possibility is to form the head by molding and fix it simultaneously to the skirt.

A third method consists in making the tube in a single operation from a preform.

The processes described above impose a choice of particular materials, plastics in general, whose physicochemical properties must be suitable for the chosen implementation.

However, these materials have certain drawbacks, notably the fact that they do not prevent the diffusion of compounds through the skirt and / or the head coming from or towards the environment of the consumable product contained in the tube. This migration phenomenon can take place between the consumable product and the outside of the tube or between the consumable product and the material that makes up the skirt and / or the head.

In order to confine and conserve the aroma or the active substances inside the tube, anti-diffusion layers, also called barrier layers, have been developed. Due to their presence, the migration phenomenon can be greatly reduced, or even completely. Such layers are described in Patent documents DE-C-19617349, FR-A-2784657, US 5372863, EP-A-496704 or WO 97/27120.

There are also anti-diffusion layers that have been developed specifically for tube heads. They are described in particular in patent documents DE-A-3215171, DE-C-4404970, US 3565293, US 4021524, US 4185757, US 5656346, FR-A-2679527, FR-A-2681006, EP-A-130239, EP-A- 524897, WO 97/27120 and WO 00/23340.

To obtain satisfactory results with the anti-diffusion layers of the prior art, it is important to give them a certain thickness, typically at least of the order of a few microns. This thickness is all the more important at the level of the head where it can sometimes reach 1 mm.

This need to use a minimum thickness results in several drawbacks. By way of non-exhaustive example, it may be mentioned that the mechanical properties of the tubes are modified due to the anti-diffusion layer.

Likewise, because of the rigidity of the tube at the level of the head, which is particularly important when inserts are used, it is not possible to remove all of the consumable product contained therein from the tube. There is always a dead volume of consumable product, inaccessible to the consumer.

Other defects related to prior art tubes can be noted

• anti-diffusion property frequently insufficient.

• presence of interior areas which are not covered by the anti-diffusion layer.

• the anti-diffusion layers are never in direct contact with the content, there is always a non-barrier layer between the anti-diffusion layer and the content, therefore a non-negligible migration in this non-barrier layer. • The anti-diffusion layers β have relatively large thicknesses, hence a relatively high cost of material and corresponding recycling problems.

The present invention has the particular merit of remedying the problems described above. It relates to a component for flexible packaging of essentially tubular shape comprising a narrow neck at one of its ends and a flat closure at the other of its ends, said packaging being intended to contain a consumable product which leaves under pressure. fingers, said component comprising an anti-diffusion layer intended to protect the consumable product from its environment, said anti-diffusion layer having a thickness of less than 150 μm.

Preferably, the anti-diffusion layer has a thickness of between 20 and 80 nm. This achieves an optimum anti-diffusion properties.

It has also been found that a particularly efficient configuration of the tube components could be obtained when the ratio between the thickness of the wall of the head and the thickness of the anti-diffusion layer was greater than 5000 and / or that the ratio between the thickness of the wall of the skirt and the thickness of the anti-diffusion layer was greater than 600.

Note also that the anti-diffusion layer according to the invention may consist of a plurality of layers of various compositions, such a configuration in particular makes it possible to obtain layers more resistant to abrasion or having better adhesion, this also allows to modify the optical properties of the tube.

Other advantages resulting from the present invention can be mentioned.

With a thin layer, it is possible to produce transparent tubes at the level of the skirt and the head. In addition, the fact of using a thin layer reduces the amount of material necessary for the manufacture of the layer, resulting in lower production costs and improved respect for the environment.

An anti-diffusion layer according to the invention can be obtained in different ways. We can cite among other things the physical vapor deposition process (PVD = Physical Vapor Deposition) which consists of thermal evaporation, resistive or using an electron gun, or a cathode or laser sputtering.

It is also possible to use the chemical vapor deposition process (CVD = Chemical Vapor Deposition).

A process particularly suited to the present invention is PECVD (Plasma Enhanced Chemical Vapor Deposition) which consists of a chemical deposition in the vapor phase assisted by plasma. The plasma can be generated remotely (remote plasma) from the area to be covered.

The use of a CVD or PECVD process, in addition to obtaining a small thickness, makes it possible to place the anti-diffusion layer in areas of the tube which cannot be covered, or even difficultly, with the layers of the state of the art. This relative inaccessibility is particularly noted at the level of the head.

In addition to the possibility of covering areas that are difficult to reach, the aforementioned methods make it possible to very precisely target the areas to be covered. For this purpose, the PECVD remote is particularly well suited, especially when it comes to leaving weld zones without an anti-diffusion layer.

Another advantage offered by the present invention lies in the fact that, in particular with the PECVD process, it becomes possible to produce an anti-diffusion layer based on silicon oxide obtained from a precursor such as HMDSO. This material has the particularity of being inert, that is to say not to encourage the migration of compounds to or from the consumable product. It also offers an effective barrier effect compared to agents external to the tube such as oxygen or humidity.

Some exemplary embodiments of the invention will be described below by means of the following figures:

Figure 1 Presentation of a tube according to the invention. Figure 2 A tube head according to the invention.

Figure 3 A device ¹ according to the invention for coating an anti-diffusion layer on the tube heads.

Figure 4 A ^2nd coating device according to the invention of an anti-diffusion layer on the tube heads. Figure 5 Device according to the invention for coating an anti-diffusion layer on tubes. Figure 6 Device of Figure 5 in another position.

The tube (1) illustrated in Figure 1 consists of a skirt (2), a head (3) and a plug (4); a flat closure (6) being formed towards the end of the tube (1) which is opposite to that where the plug (4) is located.

The head (3) mainly consists of a frustoconical shape (28) on which a cylindrical shape (7) is extended, the external surface (9) of which is threaded so as to allow the plug (4) to be screwed. An anti-diffusion layer (8) is placed over the entire interior surface of the tube (1). The thickness of the layer (8) which is obtained according to the PECVD process is of the order of 50 nm. It has in fact been found that this value is particularly suitable for obtaining an effective anti-diffusion effect.

It is also possible to obtain an effect which is still satisfactory provided that the thickness of the layer (8) is not greater than 150 nm. Conversely, with the currently known materials which are used to manufacture the anti-diffusion layer (8), for example silicon oxide, it has been observed that the thickness of the anti-diffusion layer (8) should not be less than 5 nm. However, one can imagine that in the future, anti-diffusion materials will be developed and that the thickness of the corresponding layer (8) will be less than 5 nm while retaining an optimal barrier effect.

On the tube head (3) illustrated in FIG. 2, the anti-diffusion layer (8) extends over the entire interior surface of the head (3) which is in contact with the consumable product (5) .

The tube portion (1) shown in Figure 2 is characterized in particular by a seamless zone (10) where the skirt (2) covers part of the head (3). The seamless zone (10) has substantially the shape of a cylinder whose axis merges with that of the tube (1). The weld zone (11) between the skirt (2) and the head (3) is located on the frustoconical surface (28) of the head (3).

When the tube (1) is filled with the consumable product (5) or when it is expelled from the tube (1), a certain quantity of consumable product (5) can be lodged in the seamless zone (10) above, hence the interest, as can be seen in Figure 2, to cover a portion of the outer surface of the head (3).

3 illustrates a deposition apparatus ^1, an anti-diffusion layer on the tube heads (3) which are placed on a sample holder (16), the whole being contained in a vacuum chamber (14). This device is particularly well suited when it is sought to also cover part of the external surface of the head (3).

A plasma (13) is formed at a distance (remote plasma) relative to the deposition zone. The plasma source (12) chosen in the example illustrated here is a CYRANNUS device → a description of which can be found in patent application EP-A-872164. The process for manufacturing anti-diffusion layers, in this example, is characterized by the following steps:

- Introduction of the tube heads (3) to be treated in the vacuum chamber (14).

- Establishment of a partial vacuum by means of a pumping system (15). It has been noted that a pressure between 1 and 1000 mbar is particularly suitable.

- Introduction (shown diagrammatically by reference 25) of gas or a mixture of gases which will generate the plasma directly in the plasma chamber (13). In the case of deposition of silicon oxide, it is preferable to use pure oxygen. It should be noted that it is also possible to use air from the ambient atmosphere.

- Generation of a plasma (13) in the plasma source CYRANNUS → (12) using electromagnetic waves in the microwave domain. To obtain deposition by remote plasma, this involves generating a flow of active particles towards the deposition zone. This flow is controlled by the gas flow rate and the pumping capacity as well as by suitable conduits (26) serving to direct the active particles near the tube heads (3). It has been noted that a power of plasma generation and lift between 0.1 and 10 W / cm ² is particularly advantageous.

- Introduction of a gas mixture (shown diagrammatically by reference 17) comprising a precursor between the plasma source (12) and the samples to be treated. This means avoids deposition on the walls of the plasma source (12) and minimizes the amounts of precursor. In the case of deposition of silicon oxide, the precursor can be an organosilicon such as hexamethyldisiloxane (HMDSO). This precursor can be mixed with a carrier gas such as helium or argon which prevents the formation of powder.

FIG. 4 shows a second device for depositing an anti-diffusion layer on tube heads (3). A plasma (22) is formed directly in contact with the deposition area. This process is also carried out under partial vacuum in a vacuum enclosure (23) using a pumping system (19). Typically, such a plasma can be ignited and maintained with electromagnetic waves in the radio frequency or high frequency range between the electrode (21) and the sample holder (20) acting as a counter electrode. In this case, good anti-diffusion layers of silicon oxide are obtained by directly using a mixture of gases containing oxygen and a precursor of the organo-silicon type such as HMDSO. It can also be joined to a rare gas of the helium or argon type to prevent the formation of powder. The injector (18) of the gas mixture is directly on the vacuum chamber (23).

Figures 5 and 6 illustrate a device similar to that of Figure 3 but which differs in that it is designed to allow the deposition of anti-diffusion layers on tubes (1) including the head (3) and the skirt (2) have been fixed together beforehand; the flat closure (6) being formed after the deposition and filling of the tube (1) carried out.

FIG. 5 presents the case of a remote plasma where the deposition is carried out outside the plasma source. The plasma flow and the precursor gas (17) penetrate through the tube (1) through the end opposite the narrow neck (7) and exit there through the narrow neck (7). The precursor gas is introduced (17) at the level of the guides (26) of active species.

FIG. 6 presents the case of a direct plasma where the plasma is restricted inside the tubes. In this example, batches of tubes (27) are introduced into the plasma source (12) by means of an elevator (24).

The oxygen as well as the precursor, for example HMDSO, are introduced directly into the tubes (1) by one of their ends, for example the end opposite the narrow neck (7), and exit through the opposite end. By appropriate control of the pressures inside and outside the tubes (1), thanks to the control of gas flows and pumping speeds of the orifices, the plasma is generated only inside the tubes (1 ). It goes without saying that the invention is not limited to the examples cited above. Note in particular that the anti-diffusion layer is not limited to a specific material but to any type of material constituting a layer less than 150 nm which has anti-diffusion properties.

Likewise, the invention is not limited to the coating devices described in the embodiments described above. By way of example also belonging to the field of the invention, mention may be made of devices for coating tube skirts which are treated in isolation.

Claims

claims 1. Component (2,3) for flexible packaging (1) of essentially tubular shape comprising a narrow neck (7,28) at one of its ends and a flat closure (6) at the other of its ends, said packaging (1) being intended to contain a consumable product (5) which exits under the pressure of the fingers, said component (2,3) comprising an anti-diffusion layer (8) intended to protect the consumable product (5) from its environment, characterized by the fact that said anti-diffusion layer (8) has a thickness of less than 150 nm. 2. Component according to claim 1, characterized in that the thickness of the anti-diffusion layer (8) is between 20 and 80 nm. 3. Component according to claim 1 or 2, characterized in that the anti-diffusion layer (8) consists of a plurality of layers of various compositions. 4. Component according to any one of the preceding claims, characterized in that the anti-diffusion layer (8) is located on the side of the face which is in contact with the consumable product (5). 5. Component according to the preceding claim, characterized in that the anti-diffusion layer (8) is placed so as to come into direct contact with the consumable product (5). 6. Tube head (3) comprising a layer (8) according to any one of the preceding claims. 7. Tube head according to the preceding claim, characterized in that the anti-diffusion layer (8) extends over the entire surface inside of the head (3) which is in contact with the consumable product (5). 8. Tube head according to claim 6 or 7, characterized in that a part of the external surface of the head (3) is covered by the anti-diffusion layer (8). 9. Tube head according to claim 6, 7 or 8, characterized in that the ratio between the thickness of the wall of the head and the thickness of the anti-diffusion layer is greater than 5000. 10. Tube skirt (2) comprising a layer (8) according to any one of the preceding claims. 11. Tube skirt according to the preceding claim, characterized in that the ratio between the thickness of the wall of the skirt and the thickness of the anti-diffusion layer is greater than 600. 12. Tube (1) characterized in that it comprises a layer (8) according to any one of the preceding claims, said layer spreading over the entire inner surface of the tube. 13. Component according to any one of the preceding claims, characterized in that the anti-diffusion layer (8) is obtained by a physical deposition process in the gas phase (PVD). 14. Component according to any one of claims 1 to 12, characterized in that the anti-diffusion layer (8) is obtained by a chemical vapor deposition process (CVD). 15. Component according to the preceding claim, characterized in that the process is carried out by chemical vapor deposition assisted by plasma (PECVD). 16. Component according to the preceding claim, characterized in that the plasma (13) is generated at a distance (remote plasma) relative to the area where the layer (8) is to be deposited. 17. Component according to claim 15 or 16, characterized in that the plasma is generated under a pressure between 1 and 1000 mbar and at a power between 0.1 and 10 W / cm ² . 18. A method of manufacturing a tube (1), characterized in that firstly, the layer (8) according to any one of claims 1 to 11 or 13 to 17 is placed on one or more tube components (2,3) taken in isolation and secondly, the components (2,3) are fixed together. 19. Method for manufacturing a tube (1) consisting of a head (3) and a skirt (2), characterized in that the two components (2,3) are first fixed to each other, the flat closure (6) not yet being formed at this stage, the layer (8) according to any one of claims 1 to 5 or 12 to 15 then being placed inside the assembly formed by the two components (2,3), then the consumable product (5) is introduced on the side of the skirt (2) which is opposite to the head (3), the flat closure (6) being finally formed. 20. Method according to the preceding claim, characterized in that the layer (8) is put in place according to the method of any one of claims 16 or 17 and that the plasma flow enters through an orifice of the head assembly -skirt and exit through the second orifice of this same set.