BAG-ON-VALVE SYSTEM AND FILM LAMINATE FOR AGGRESSIVE FILLING MATERIALS

Abstract

The present invention relates to a bag-on-valve system (10) comprising a pressure container (12) having a substantially flexible filling material container (14) which is received therein and in which a filling material (22) having unsaturated compounds, preferably terpenes, particularly preferably limonenes, is received and can be removed from the bag-on-valve system (10) by means of a selectively actuatable valve (20), a propellant, preferably a propellant gas, being provided in order to support the removal between the pressure container (12) and the filling material container (14) so that a flexible sheath (16) of the filling material container (14) is in contact with the filling material (22) at the inner side (16a) thereof and is in contact with the propellant at the outer side (16b) thereof, the sheath (16) of the filling material container (14) further being substantially formed from a flexible film laminate (30) which has a metal layer (32), a plastics layer (42) and a thermally sealable sealing layer (38) in the sequence mentioned in the direction from the outer side (16b) to the inner side (16a), wherein the plastics layer (42) is a polyester layer, preferably a layer of aromatic polyester, more preferably a terephthalate layer, particularly preferably a polyethylene terephthalate layer.

Description

The present invention relates to a bag-on-valve system comprising a pressure container having a substantially flexible filling material container which is received therein and in which a filling material having unsaturated compounds, preferably terpenes, particularly preferably limonenes, is received and can be removed from the bag-on-valve system by means of a selectively actuatable valve, a propellant, preferably a propellant gas, being provided in order to support the removal in the pressure container but outside the filling material container so that a flexible sheath of the filling material container is in contact with the filling material at the inner side thereof and is in contact with the propellant at the outer side thereof, the sheath of the filling material container further being substantially formed from a flexible film laminate which has in the direction from the outer side to the inner side a metal layer, a plastics layer and a thermally sealable sealing layer in the sequence mentioned.

Such bag-on-valve systems are used, for example, as the packaging of cosmetic and hygiene articles such as, for example, shaving gel.

Bag-on-valve systems as packaging means are advantageous because they afford the possibility of providing a propellant for supporting the emptying of the packaging in a manner spatially separated from the filling material so that there cannot be any interactions at all between the filling material and propellants which may be disadvantageous either to the quality of the filling material and/or to the efficacy of the propellant.

However, a particular problem exists in packagings of the bag-on-valve system type in that the flexible sheath of the filling material container may be in contact with aggressive media at both sides, that is to say, both at the inner side and at the outer side thereof. At the outer side, there is contact between the sheath of the filling material container and the propellant. This contact is generally less critical because bag-on-valve systems allow the use of air or inert or quasi-inert gases, such as, for example, nitrogen, as the propellant.

At the inner side, the sheath is in contact with the filling material. The measures which must be taken in respect of the sheath, in order to be able to ensure that the filling material can be received in the filling material container in a resistant manner over time, depend very greatly on the nature of the filling material.

Limonene-containing filling materials in particular, whose chemical aggressiveness is based on the presence of unsaturated compounds, have been found to be aggressive filling materials. Therefore, filling materials having unsaturated compounds are generally considered in the following to be sufficiently chemically aggressive for particular measures to have to be taken in respect of the sheath in order to be able to ensure its integrity over the expected duration of use.

Within the filling materials having unsaturated compounds, filling materials having cyclically unsaturated compounds form a subgroup having elevated chemical aggressiveness. Within that group, terpenes again exhibit an even higher level of chemical aggressiveness. Finally, within the terpenes, the limonenes occupy a special position owing to their chemical aggressiveness which is even more elevated.

The sheath of the filling material container is produced from a flexible material, generally a flexible film, in order to be able to reduce the volume of the filling material container when the bag-on-valve system is emptied by the propellant which acts from the outer side and consequently in order to be able to remove a generally incompressible or quasi-incompressible filling material when the valve is actuated accordingly.

Conventional bag-on-valve systems use, as the material for the flexible sheath of the filling material container, a flexible film laminate which comprises an aluminium layer, a layer of orientated polyamide and a thermally sealable layer in the direction from the outer side towards the inner side. However, it has been found that those film laminates sometimes tend to delaminate when they come into contact with the above-mentioned aggressive filling materials and/or the aluminium layer is corroded by the aggressive filling materials, in particular by limonene-containing filling materials.

It may be the case that filling material containers and therefore the entire bag-on-valve system are already attacked in terms of their structural integrity a short time after being filled with filling materials having unsaturated compounds, in particular with filling materials having limonene-containing filling materials, by those materials to such an extent that the packaging system fails. The durability of the bag-on-valve system may, in an undesirable manner, be clearly below the expected or required duration of use.

Therefore, an object of the present invention is to provide a technical teaching which allows the service-life of bag-on-valve systems for the above-mentioned critical filling materials to be increased so that it becomes possible, in principle, also to package and offer the above-mentioned critical filling materials having unsaturated compounds in bag-on-valve systems.

This object is achieved according to the invention by a bag-on-valve system of the type mentioned in the introduction, in which the plastics layer is a polyester layer. It has surprisingly been found that polyester is capable of retaining in a durable manner components of filling materials having unsaturated compounds and thus protecting the metal layer from contact with aggressive filling materials or the components thereof.

Within the possible layers of polyester, layers made of aromatic polyester provide even greater protection of the metal layer against the aggressive filling materials mentioned. Terephthalate layers such as, for example, polybutylene terephthalate and polyethylene terephthalate have been found to be particularly effective in shielding the metal layer against the aggressive filling materials, of which particularly polyethylene terephthalate has exhibited outstanding shielding properties against aggressive filling materials having unsaturated compounds.

As usual, a polyolefin layer can be used as a sealing layer, polyethylene layers or polypropylene layers having been found to be particularly reliable and cost-effective.

In order to better bond the polyester layer and the sealing layer to each other, a bond promoting layer may be provided between them. A bond promoting layer may also be provided between the metal layer and the polyester layer although in principle it is not intended to be excluded that the polyester layer is coated on one side with a metal, in particular aluminium, for example, by evaporation deposition or sputtering.

In order to protect the outer side of the sheath, that is to say, in particular to protect the metal layer from the propellant, there may be provision for the flexible film laminate to have an additional polyester layer so that the metal layer is provided between the above-mentioned polyester layer and the additional polyester layer mentioned now.

As polyesters having an increasing protective effect aromatic polyesters, terephthalates and particularly preferably polyethylene terephthalate may again be considered as a layer material. In accordance with the propellant actually used, however, in place of the polyester layer, a layer of a different material may also be provided at the side of the metal layer directed towards the propellant.

A bond promoting layer may again be provided between the metal layer and the additional polyester layer.

Particularly in the case of very aggressive filling materials, such as limonene-containing filling materials, it has surprisingly been found that the combination of a polyester layer and a bond promoting layer results in a significant increase of the service-life of the sheath formed from the film laminate described.

If, for example, polyurethane is used as the bond promoting layer, it is possible, on the one hand, to prevent delamination and, on the other hand, to increase the shielding action with respect to the metal layer.

Aromatic polyurethane has been found to be particularly effective as a bond promoting material. In particular the combination of a polyethylene terephthalate layer with a bond promoting layer made of aliphatic or aromatic polyurethane achieved both outstanding stability of the laminate and outstanding shielding of the metal layer with respect to the filling material and the components thereof. The use of acrylates as bond promoters may also be envisaged in order to achieve a shielding action together with the polyester layer.

In principle, various metals are conceivable for producing the metal layer, but a layer of aluminium, that is to say, an aluminium alloy, is preferable for reasons of cost with a high level of efficacy.

In principle, it is not intended to be excluded that the film laminate which forms the flexible sheath of the filling material container comprises additional layers in addition to the above-mentioned layers. However, this is not necessary. For instance, it is preferable for reasons of cost for the sealing layer to form an inner face of the sheath which comes into contact with the filling material.

There may also be provision, although this is not absolutely necessary, for the above-mentioned additional polyester layer to form an outer face of the sheath which is in contact with the propellant.

In order to ensure the shielding action of the polyester layer, it should have a minimum thickness of 6 μm. The thickness is preferably in a range between 8 μm and 20 μm, with a preferred thickness of 12 μm.

Since the present invention confers a particular value on a filling material container for a bag-on-valve system, the Applicant is seeking independent protection for a filling material container having a substantially flexible sheath, as described above for use for filling material containers of bag-on-valve systems.

The Applicant has further recognised that the above-described film laminate for use in bag-on-valve systems, in particular for producing filling material containers for bag-on-valve systems, already solves the problem mentioned in the introduction and consequently constitutes a particular value, for which reason the Applicant is also seeking protection for a film laminate comprising a metal layer, preferably an aluminium layer, a terephthalate layer and a thermally sealable layer having at least one bond promoting layer preferably made of an aliphatic or aromatic polyurethane or an acrylate arranged therebetween. The film laminate can further be developed in accordance with the above indications. Reference is made to the above explanations with regard to the advantages of the individual developments. Finally, the use of such a film laminate for producing filling material containers of bag-on-valve systems also constitutes a technical teaching for increasing the durability of bag-on-valve systems having aggressive filling materials and therefore a solution to the problem mentioned in the introduction.

The present invention is explained below with reference to the appended Figures, in which:

FIG. 1 is a schematic longitudinal section of a bag-on-valve system according to the invention and

FIG. 2 is a cross-section of a particularly preferred film laminate for producing filling material containers of the bag-on-valve system of FIG. 1.

In FIG. 1, one embodiment of a bag-on-valve system according to the invention is generally designated 10. The bag-on-valve system 10 comprises a pressure container 12 which surrounds a filling material container 14.

The pressure container 12 may be formed, for example, from metal or rigid plastics material or a compound of a plurality of materials.

The filling material container 14 comprises a substantially flexible sheath 16 and a removal channel 18, via which filling material 22 can be removed from the inner region 24 of the sheath 16 by actuating a valve 20 which releases or blocks the removal channel selectively, for instance, by pressure activation.

The pressure container 12 consequently has, apart from the inner region 24 of the sheath 16, a propellant region 26 which is located between the sheath 16 and the inner wall 12a of the pressure container 12.

For example, compressed air or another pressurised, preferably inert or quasi-inert, gas may be used as the propellant. This is particularly advantageous because inert or quasi-inert gas acting as a propellant is non-flammable or at least hardly flammable in contrast to conventional flammable propellants.

When the filling material 22 comprises unsaturated compounds and consequently has an elevated level of chemical aggressiveness, it is recommended that the film laminate illustrated in FIG. 2 be used to produce the filling material container 14.

The film laminate which is shown in FIG. 2 and which is generally designated 30 has a metal layer 32 which is preferably an aluminium layer. Towards the inner side 16a of the sheath 16, which is in contact with the filling material 22, there is provided a polyester layer 34 which is formed in a particularly preferable manner from polyethylene terephthalate-12 and which is connected to the metal layer 32 in order to increase the shielding effect relative to the metal layer 32 with a bond promoting layer 36 being interposed. Aromatic polyurethane adhesive is preferably used as the bond promoter because the combination of polyethylene terephthalate-12 and aromatic polyurethane adhesive has demonstrated a particularly high level of laminate stability and a particularly high shielding effect for protecting the metal layer 32 from the filling material 22.

Further inwards, there is provided a thermally sealable sealing layer 38 made of a polyolefin, for instance, polypropylene or polyethylene, and which allows a sealing connection with respect to other film laminate pieces and consequently the formation of a closed sheath 16 made of a film laminate 30. For the reasons already mentioned above, the sealing layer 38 is also preferably connected to the polyester layer 34 by an additional bond promoting layer 40, aromatic polyurethane adhesive again constituting the preferred bond promoting material.

The sealing layer 38 may form the inner face 16a of the sheath 16.

Towards the outer face 16b of the sheath 16, the metal layer 32 may again be protected by a plastics layer 42 against the influences of the propellant in the propellant region 26. The plastics layer 42 is preferably a polyester layer, particularly preferably polyethylene terephthalate-12, that is to say, a layer having a thickness of approximately 12 μm.

For the reasons already explained above, the plastics layer 42 is connected to the metal layer 32 by a bond promoting layer 44, that bond promoting layer also preferably using aromatic polyurethane adhesive as the bond promoting material.

The film laminate described also remains stable and does not delaminate over a long period of time of, for instance, more than a year, even in the event of direct contact of the sealing layer 38 with limonene-containing filling material. No appearances of corrosion at all can also be seen on an aluminium layer 32 acting as the metal layer 32. Therefore, bag-on-valve systems can also be used for packaging such chemically aggressive filling materials as limonene-containing filling materials.

The layer thicknesses shown in FIG. 2 do not indicate the actual layer thicknesses of the film laminate to scale. FIG. 2 is merely a highly schematic illustration, from which substantially only the layer structure is intended to be taken with regard to the material sequence.

Claims

1. Bag-on-valve system comprising a pressure container having a substantially flexible filling material container which is received therein and in which a filling material having unsaturated compounds, preferably terpenes, particularly preferably limonenes, is received and can be removed from the bag-on-valve system by means of a selectively actuatable valve, a propellant, preferably a propellant gas, being provided in order to support the removal in the pressure container but outside the filling material container so that a flexible sheath of the filling material container is in contact with the filling material at the inner side thereof and is in contact with the propellant at the outer side thereof, the sheath of the filling material container further being substantially formed from a flexible film laminate which has a metal layer a plastics layer and a thermally sealable sealing layer in the sequence mentioned in the direction from the outer side to the inner side,

characterised in that the plastics layer is a polyester layer, preferably a layer of aromatic polyester, more preferably a terephthalate layer, particularly preferably a polyethylene terephthalate layer.

2. Bag-on-valve system according to claim 1, characterised in that the sealing layer is a polyolefin layer, preferably a polyethylene layer or polypropylene layer.

3. Bag-on-valve system according to claim 1, characterised in that a bond promoting layer is provided between the polyester layer and the sealing layer.

4. Bag-on-valve system according to claim 1, characterised in that a bond promoting layer is provided between the metal layer and the polyester layer.

5. Bag-on-valve system according to claim 1, characterised in that the flexible film laminate has an additional polyester layer, more preferably a layer of aromatic polyester, even more preferably a terephthalate layer, particularly preferably a polyethylene terephthalate layer so that the metal layer is provided between the polyester layer and the additional polyester layer.

6. Bag-on-valve system according to claim 5, characterised in that a bond promoting layer is provided between the metal layer and the additional polyester layer.

7. Bag-on-valve system according to claim 6,

characterised in that the bond promoting layer comprises acrylates or polyurethane, preferably aliphatic or aromatic polyurethane, and is preferably a layer of aromatic polyurethane.

8. Bag-on-valve system according to claim 1,

characterised in that the metal layer is an aluminium layer.

9. Bag-on-valve system according to claim 1,

characterised in that the sealing layer forms an inner face of the sheath.

10. Bag-on-valve system according to claim 5, characterised in that the additional polyester layer forms an outer face of the sheath.

11. Filling material container having a substantially flexible sheath according to claim 1, in particular filling material containers for bag-on-valve systems.

12. Film laminate for use in bag-on-valve systems, comprising a metal layer, preferably an aluminium layer, a terephthalate layer and a thermally sealable layer having at least one bond promoting layer arranged therebetween, made of, preferably aromatic, polyurethane, particularly preferably together with one or more of the developments of the laminate according to the features of claim 2.

13. Use of a film laminate according to claim 12 for forming filling material containers of bag-on-valve systems.