Patent Application
20120097707
The present invention relates to a device for packaging and dispensing fluid products, and more particularly a flexible pocket for a device for packaging and dispensing fluid products, that are liquid or pasty, of the pocket-vial type, that is to say comprising a flexible pocket placed in a rigid receptacle and associated with a pump or a valve making it possible to keep the fluid product in the flexible pocket away from the air in good conditions and to dispense if from the pocket by actuating the pump or the valve.
Devices for packaging and dispensing fluids of the pocket-vial type are well known. These devices usually comprise a receptacle with a rigid shell in which a retractable flexible pocket is placed which retracts gradually as the product is extracted therefrom. The product can be expelled from the pocket by means of an “airless” pump or under the pressure of a propellant gas acting in the vial, on the wall of the pocket. In the case of expelling the product from the pocket by means of an airless pump, a vent is provided, usually in the bottom or in the neck of the vial, to allow the outside air to enter the space situated between the vial and the pocket on each actuation of the pump and thus to allow the pocket to retract by maintaining sufficient pressure on its walls.
An exemplary embodiment according to this technique is described in patent FR 2.723.356 relating to a device comprising a pocket, made of flexible plastic, such as polyethylene or polypropylene, placed in a rigid receptacle, the neck of which comprises an air inlet.
Another example of a pocket-vial is described in patent FR 2.827.844 relating to a device comprising a sealed flexible pocket placed in a rigid vial, associated with a pump or a valve, in which the pocket comprises a cylindrical wall consisting of a metal or plastic sheet wound over the sides of two end-pieces of which one forms the bottom of the pocket and the other a ring for attachment to the vial and to the pump or the valve.
Application WO 97.20757 describes a method for manufacturing a plastic tubular pocket designed for an aerosol, the opening of which is sealed to a ring while the other end is folded and sealed to form the bottom of the pocket.
The products contained in the pockets are often sensitive to oxidation under the action of the oxygen of the air and can deteriorate if air gets into the pocket because of a lack of a seal. Sealing defects are most frequently encountered at the junction of the pocket and the pump. They may also result from a certain porosity of the materials used for producing the pocket. Moreover, the wall of the pocket of the known devices may form folds when retracting and these folds risk causing tears capable of allowing air to pass through which then reaches the inside of the pocket and consequently compromises the preservation of the integrity of the product contained therein. Finally, the folds formed by the wall of the pocket during its retraction cause volumes of retention of product and thus limit the effectiveness of the dispensing of the latter.
One technique for limiting the risk of the pocket tearing is described in patent FR. 2.770.834 which proposes to include in the pocket, made of flexible material such as plastic or aluminum sheet, a free float preventing too great a retraction of the pocket and thus limiting the risks of tearing. However, the drawback of this technique is that it forms considerable retention volumes.
Pocket-vials are routinely manufactured by extrusion or injection of plastic materials. The vial may be manufactured by stamping in the case of a wall made of metal such as aluminum, or by injection or injection blow-molding in the case of a wall made of plastic, while the flexible pocket is usually manufactured by injection blow-molding or extrusion blow-molding of polyethylene or of polypropylene in a suitable mold.
The pockets may also be made of aluminum sheets or of multi-layer materials of the plastic/aluminum type having good sealing qualities of their wall, as in aforementioned patent FR 2.827.844. The pockets of this type are made in the form of superposed sheets, sealed at their side, fitting to a neck or a rigid ring. The manufacture of such pockets is relatively simple, but it has the drawback that the junction zone of the two opposite sides of the sheet to form the cylinder has an extra thickness. Moreover, this extra thickness allows the thickness of the layer forming the sheet to appear and the risk of migration of traces of compounds contained in the layer to the product inserted into the pocket is not inconsiderable in this unprotected zone, particularly in the case of a multi-layer film comprising a metal layer. U.S. Pat. No. 5,248,063 describes a laminated pocket formed from a multi-layer sheet the edge of which is covered by a plastic film in order to prevent, the sheet from delaminating. A technique for applying a tape to the adjacent sides of a sheet wound in a cylinder is described in U.S. Pat. Nos. 3,066,063 and DE 1,729,018.
Various techniques for sealing the two sides of a sheet together are known, as in patents FR 2.511.974 and CA 1.003.350, but it is often difficult to obtain and maintain a good seal of the seals of the edges of the metal sheets, for example made of aluminum, because of the deformations and the stresses to which they are subjected during use. If the seal is reinforced and forms a fold to ensure the seal, the result thereof is a rib which compromises the correct retraction of the pocket and the delivery of the products that it contains.
There is therefore a need for devices of the pocket-vial type that have good security by reducing as much as possible the risk of contamination between the material forming the wall of the pocket and the product that it contains.
There is also a need for devices of the pocket-vial type that are simple and cheap to manufacture, comprising a pocket that can be easily adapted to the quantities of products that it is desired to insert therein and to the volume of the vial, without excessive dead volume between pocket and vial, without loss of seal and that are easily recyclable, while providing good mechanical strength.
The precise subject of the invention is a device for packaging and dispensing fluid product of the pocket-vial type having good security against the risks of contamination of the products contained in the pocket.
A further subject of the invention is a method for manufacturing a pocket-vial, said method being able to use materials that are simple or complex depending on the envisaged use, and are easily recyclable, using minimal quantities of material for the vial and for the pocket and having excellent mechanical strength, more particularly excellent impact resistance.
The device for packaging and dispensing fluid product according to the present invention is of the type comprising a sealed flexible pocket placed in a rigid vial, associated with a pump or a valve, the pocket comprising a cylindrical wall consisting of at least one sheet wound in a cylinder of which one of the lateral sides is attached in a sealed manner to a solid end-piece forming the bottom of the pocket, and the other is attached in a sealed manner to an annular end-piece forming a ring for attachment to the vial, and it is remarkable notably in that the two longitudinal sides of the sheet are attached to one another in a sealed manner and the edge of the inner side is masked by a flexible covering strip.
According to one embodiment of the invention, the covering strip is attached to each of the two longitudinal sides of the sheet, on either side of their junction on the inner wall of the sheet.
According to another embodiment of the invention, the covering strip envelops the edge of the inner side of the sheet and is folded between the two sides. It is then sealed at the same time as the sides of the sheet during the formation of the cylindrical tube. The width of the covering strip varies depending on the dimensions of the pocket, but it is usually between 2 and 10 mm and preferably between 4 and 6 mm.
As indicated above, the sheet used to form the wall of the pocket may consist of various simple or complex materials, depending on the envisaged use. Its thickness may vary from 20 μm to 250 μm approximately and is preferably between 50 μm and 150 μm in order to provide the best conditions of operation, in particular of easy retraction of the pocket in the vial gradually as it empties, so as to provide an excellent delivery rate, greater than 90%. These values may vary depending upon the materials used.
The sheet, which may be single-layer or multi-layer, is attached by its sides to the periphery of each end-piece and closed along a generatrix of the cylinder.
According to one embodiment, the cylindrical pocket comprises a multi-layer complex associating several metal films, or one metal sheet coated with a plastic film on at least one of its faces. This multi-layer complex is wound over two end-pieces which may be for example made of metal or of plastic. One particularly advantageous embodiment comprises an aluminum sheet inserted between at least two plastic films. The plastic films of the multi-layer complexes may be chosen from a polyethylene, a polypropylene, polyamide, etc.
The multi-layer sheet is attached by its sides to the periphery of each end-piece and closed along a generatrix of the cylinder.
According to another embodiment of the invention, the multi-layer sheet is a plastic/barrier polymer/plastic complex and for example an EVOH film inserted between two films of polyethylene or of polypropylene. EVOH is an ethylene/vinyl alcohol polymer providing good characteristics as a barrier to gases, in particular to oxygen and to water vapor.
The complex may also comprise four layers, namely polyethylene/polyamide/aluminum/polyethylene terephthalate or else polyethylene/polyethylene terephthalate/aluminum/polyethylene. The latter multi-layer structure has the advantage of making the side-to-side attachment easier after winding of the sheet, by bonding or by sealing, since the inner portion of one side of the sheet is applied to the outer portion of the other side, which is made of the same material.
Such a multi-layer composite coating is particularly useful when a strong seal is essential, or when the nature of the product contained in the pocket requires it.
According to one variant, it is possible to use an aluminum sheet wound over two metal or plastic end-pieces, two opposite sides of the sheet being sealed to one another along a generatrix of the cylinder.
In all cases, a covering strip is placed on the inner face of the sheet forming a tube, over the junction of the two sides, as indicated above. The covering strip is preferably made of a material identical to that forming the inner layer of the sheet. For example, it is advantageous to use a sheet comprising at least one layer of polyethylene as an inner layer, and a covering strip made of the same polyethylene.
This makes it possible to ensure continuity of the material forming the inner layer of the pocket in contact with the product that is inserted therein. The fluid product is therefore in limited contact with only one material. Moreover, once sealed, the covering strip has substantially the same thickness as the inner layer of the sheet.
According to another variant, a sheet of flexible cardboard or a polymer/paper/polymer complex, preferably polyethylene/paper/polyethylene, is used. This type of material has the advantage of being more easily recyclable than the PE/PET/aluminum/PE multi-layers used in the technical field.
As indicated above, the metal sheet, or the multi-layer sheet, is attached to the periphery of each of the two end-pieces, preferably by bonding or by sealing, depending on the nature of the material used for the end-pieces.
The method of the invention consists first of all in cutting the sheet to the desired size, in sealing the two opposite sides of the sheet, from the inside to the outside in order to form an open tubular pocket that is then attached by its openings to the end-pieces, then the pocket is inserted into the rigid vial in which it is held by the annular end-piece forming a ring. Then, the covering strip is cut and then sealed to the sheet, on the inside. The sheet is then wound round itself, keeping the covering strip on the inside and taking care that it correctly covers the contact zone between the ends. The sealing is then carried out and a sealed tube is obtained with continuity of the inner zone.
The attachment of the sides to one another, then to the end-pieces, can be carried out by conventional sealing techniques, for example ultrasound, impulse, friction or heat sealing. Preferably the heat-sealing technique that is best suited to the materials used to form the wall of the pocket is used. The attachment can also be carried out by bonding but only if the products that the pocket is designed to contain do not risk any deleterious effect resulting from a possible contamination by the components of the adhesives.
The sheet initially has a flat shape, making it necessary to make use of tooling suitable for shaping it and then inserting the product therein. The operations of filling the pocket used in the invention do not require initially creating the vacuum in the pocket before carrying out a partial filling, and then, in a last step, operating under a neutral gas, unlike most of the pockets known in the prior art.
One of the advantages of the method of the invention is that it makes it possible to obtain pockets with relatively large volumes (more than 150 ml for example) with a perfectly cylindrical shape because of the sealing method.
The method according to the present invention notably has the advantage of making it possible to manufacture pockets of which the volume is easily adapted to that of the vial and to the quantity of product that is to be inserted into the pocket. This is particularly advantageous from a manufacturing point of view since the conventional techniques, because of their cost, involve limiting the ranges of vials to a few models with predetermined dimensions, and for example rigid vials are commonly proposed in which the volume is 30, or 90 ml and consequently a pocket that has a content of 65 ml, for example, can be inserted only in a 90 ml vial, resulting in a considerable dead volume between the pocket and the vial. According to the technique of the invention, the volume of the pocket being easily adapted to that of the vial simply by varying the height and the diameter of the cylinders forming the pocket and the vial, it is possible to reduce the dead volumes.
This provides an additional advantage in the case of relatively volatile products, such as alcohols, contained in the pocket, which may partially pass through the wall depending on the materials used: the reduced dead volume is quickly saturated which then limits the product losses.
Moreover, vertical impact tests using drop testing carried out on the basis of the ASTM standard D 6344-4 have shown a substantial improvement in impact resistance while the presence of the covering strip introduces a dissymmetry capable of compromising strength. Moreover, the zone of weakness is situated on the sealing of the two sides together and this weakness is all the greater the longer the seal becomes. Specifically it is known that the thickness has little influence on the strength, unlike the length of the seal.
The tests have also shown that the impact resistance is greatly improved when the assembly of the sides of the sheet forming the pocket is carried out so that the inner surface of one side is in contact with the outer surface of the other side by comparison with a pocket made according to the conventional methods in which the sides are folded toward the outside of the cylinder, the inner surfaces of the sides being in contact with one another.
The test consists in dropping pocket-vials oriented vertically from a height varying from 0.6 in to 4 m.
Each pocket consists of a multi-layer sheet attached by bonding to two end-pieces as indicated above. The layers, from the outer layer to the inner layer, are polyethylene/polyethylene terephthalate/aluminum/-polyethylene. The thickness of the polyethylene layers is 50 μm and that of the aluminum and polyethylene terephthalate layers is 12 μm. The pockets according to the invention comprise a polyethylene strip that is 100 μm thick.
The pockets, of cylindrical shape and having a capacity of 100 ml, are filled with water. They are placed in a rigid polyethylene vial, the assembly of the pocket to the vial being achieved by the upper annular ring of the pocket as shown in
The drop is guided by means of a vertical tube with a diameter slightly larger than that of the vials in order to keep their orientation and ensure regularity of the conditions of impact on a hard surface. The orientation of the pocket-vials is such that the bottom of the vial, strikes the ground first.
The tests are carried out over 3 series of 20 pocket-vials. All the pocket-vials have the same dimension (vial height: 137 mm, diameter: 42 mm). The first series includes standard pockets with sides folded outward sealed inner face to inner face. The second series comprises pockets with sides sealed to one another, inner face to outer face. The third series comprises pockets according to the present invention.
The first test is run by dropping the vial from a height of 0.60 m. The vials withstanding the first test are then subjected to a second test at 1.2 m. Those that withstand are then subjected to a third test at 2.0 m, then at 3.3 m and finally at 4.0 m if they have withstood the previous tests.
Each vial is tested three times at each height.
The results of the measurements are shown below.
The table indicates the number of failures. Thus, all the pocket-vials withstood the first test (no failure). In the first series (standard pocket) none of the 20 pocket-vials withstood the 2.0 m drop. The pocket-vials of the second series withstood the drop at 3.3 m but 6/20 did not withstand the drop at 4.0 m. On the other hand, all the pocket-vials of the third series (invention) withstood the drop at 4.0 m.
An improvement is therefore found in impact resistance despite the presence of an additional seal.
A test for measuring burst resistance showed that the pockets according to the invention have a better resistance than the pockets manufactured according to the conventional techniques. Therefore the burst resistance of a pocket with a multi-layer sheet identical to that used in the above test is 3.1 bar (3.1 105 Pa) while that of a standard pocket with sides folded outward and sealed inner face to inner face is only 1.9 bar (1.9 105 Pa) in the same conditions.
These results are obtained without loss in the delivery rate, that is to say that the covering strip has no negative effect on the delivery rate.
An exemplary embodiment of a pocket-vial according to the present invention is described below with reference to the appended drawings which represent:
Once she sheet (1) has been wound, its two ends are superposed at the zone (5), the inner face close to the side being placed on the outer face close to the other side. The width of the zone of superposition of the two sides of the sheet is approximately 5 mm. The two sides are attached to one another by
The width of the sheet is variable and corresponds to the height of the pocket, once the tube has been formed and placed over the end-pieces.
Moreover, the same material, in this example polyethylene, is used over the whole inner surface of the sheet that is then in contact with the product in the pocket. There is therefore no break in the quality of the material forming the inner face of the pocket. The polyethylene covering layer makes it possible to mask the edge of the inner side of the sheet and prevent any contact of the aluminum with the product inserted into the pocket, and its small thickness, of the order of 50 to 150 μm, and preferably approximately 100 μm, causes only a negligible extra thickness.
This variant makes the sealing operations easier depending on the tooling used since the covering strip (6) is first attached and sealed to one of the sides of the multi-layer sheet (1), then the sheet is wound in a cylinder and the sealing of the two sides and of the covering strip is then carried out.
A pump (not shown) supporting a button for its actuation is mounted in a sealed manner on the neck of the pocket according to the technique of patent FR. 2.827.844.
An air circuit (not shown) is provided, according to a usual technique, in the pump or in the annular end-piece forming an attachment ring in order to allow air to pass from the outside to the space between the pocket and the vial. Means are provided for the air circuit to be open only when the pocket-vial is used, for example by a known closure system that opens only in the event of pressure on the button for actuating the pump so as to allow the entry of only a volume of air equivalent, to the volume of fluid expelled from the pocket. For example, the means for closing off the air circuit may consist of valve elements which remain closed unless the pump is actuated. According to a variant (not shown), this air circuit may be replaced by a simple vent in the bottom of the vial. If necessary, this vent may be furnished with a valve element and a filter.
As shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 0952774 | Apr 2009 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2010/050804 | 4/28/2010 | WO | 00 | 1/9/2012 |
