Patent Application
20190161268
The present invention relates to an improvement in sealing performance and attachment between a valve cup and a container for dispensing a fluid medium stored under pressure and also to a method of assembling such a dispensing system for dispensing a fluid medium stored under pressure.
Systems for dispensing a fluid medium stored under pressure are well-known and typically include a container, a valve, and a valve cup, wherein the valve cup supports the valve, usually centrally, and also closes off an opening of the container. The inner volume of the container is pressurized and maintained in such a state by the valve and seals between the valve cup and valve, and the valve cup and the container opening. When the valve is actuated, the pressure difference between the inner volume of the container and the outside environment causes the fluid medium to be expelled from the container. Some systems employ a two-stage container having an inner and outer container, one of which contains the propellant gas, whereas others may employ a single container with the fluid medium also acting as the propellant.
Traditionally, the containers are made from a metal, usually aluminium. Recently, there has been an increasing trend to use plastics, namely polyethylene terephthalate (PET), as the containers for these dispensing systems for various advantages such as cost and ease of manufacturing, among others. In all cases, however, the systems should be stable and be able to withstand the internal pressures of the container while also providing an adequate seal.
Conventional systems employing PET containers also typically use a metal, e.g., aluminium, for the valve cups which ensures a suitable sealing engagement between the valve cup and valve. The valve cup may be clinched to a lip of the opening of the container. While the attachment between the valve cup and container is often sufficient at most normal operating temperatures, higher temperatures can cause the PET container to deform to a large degree such that the connection between the aluminium valve cup and container opening is no longer fluid tight. This is highly disadvantageous as the propellant gas and/or the fluid medium can escape from the container.
European safety requirements specify that aerosol systems should not be exposed to temperatures above 50° C. However, in practice, such dispensing systems may be subject to much higher temperatures.
A dispensing system exhibiting sufficient sealing performance at temperatures greater than 50° C. is therefore required that preferably enables the container and/or the valve cup to be made of plastics materials in order to take advantage of the considerable benefits of using these materials.
According to a first aspect of the present invention there is provided a fluid medium dispensing system comprising:
It has been surprisingly found that securing the valve cup to the neck of the container by using an adhesive layer not only secures the valve cup in position but also creates a seal that enables the dispensing system to withstand internal pressures of up to 13 bar. Such a seal has the advantage that it is simple and economical to employ.
Preferably, the adhesive is a cyanoacrylate adhesive, which advantageously comprises ethyl cyanoacrylate.
In some embodiments a bag is attached to the valve such that its inner volume is in fluid communication with channels upstream and downstream of the valve when the valve is actuated and therefore open but is not in fluid communication with an interior volume of the container between the inside wall of the container and the outside surface of the bag. In these embodiments the bag contains the fluid medium to be dispensed by the system and the interior volume between the inside wall of the container and the outside surface of the bag contains a pressurized gas for use as a propellant.
Such bag-on-valve (BoV) packaging technologies are advantageously used for many consumer products, in particular for pharmaceutical and healthcare products. They have many advantages, in particular there is no need to use flammable propellants and they can be used with pressurized air or nitrogen. This is particularly important in the present invention as such a propellant will not have an adverse effect on the adhesive seal between the valve cup and the neck of the container.
A method of for assembling such a BoV dispensing system for dispensing a fluid medium is therefore required.
According to a second aspect of the present invention there is provided a method of assembling a dispensing system for dispensing a fluid medium stored under pressure, the method including:
In this method, a bag is attached to a valve which forms part of a valve cup. The valve cup and bag are subsequently inserted in the container and positioned adjacent to the opening of the container. In this state, the inner volume of the container may be pressurized using a propellant gas, preferably by undercup gassing. That is, the volume between the bag and container may be pressurized. Assembling the dispensing system in this way allows for the pressurized container to be attached to the valve cup in a state ready to receive the fluid medium to be dispensed by the system.
Preferably, the adhesive layer is formed from a cyanoacrylate adhesive.
Preferably also, the adhesive comprises ethyl cyanoacrylate.
Such adhesives have the advantage that they can be applied and allowed to cure at an ambient temperature between 20° C. and 25° C. Also, such adhesives cure at normal relative humidities, typically those of at least 35% and preferably those of 50%. Hence no special environmental conditions are required during the assembly of the fluid dispensing system according to the invention.
Also, only a small quantity of such adhesive is required to produce the seal. This is dependent on the bonding gap between the valve cup and the neck of the container. However, in dispensing systems the gap is usually kept to an absolute minimum and valve cup is preferably either push-fitted or snap-fitted into the neck of the container. Such an arrangement enables quantities of adhesive of less than 1 g to be employed. Also, the push- or snap-fitment holds the valve cup in position in the neck of the container during curing of the adhesive. Whilst cyanoacrylate adhesives cure quickly, for example a typical ethyl cyanoacrylate adhesive cured for 10 seconds at 22° C. exhibits a tensile strength equal to or in excess of 6.0 N/mm2, preferably the adhesive layer is allowed to cure for up to 72 hours in order to develop higher tensile strengths in excess of 13.0 N/mm2.
Plastic containers may be advantageous for various reasons when compared to metal containers, e.g., because of cost or ease of manufacturing. Polyesters, and in particular PET, have many advantageous qualities in packaging applications. They can be easy to manipulate and thus forming containers of PET may be relatively easier and quicker than forming them of metal. In some cases, the polyesters may also be relatively cheap. Some polyesters can also be recycled thus reducing the overall overhead cost. Finally, some polyesters can also be sterilized which is particularly advantageous for medical applications.
Hence, in one embodiment of the system above, at least the neck of the container is preferably formed from a first plastics material, which is preferably a polyester. Advantageously, the container is formed from polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).
However, some plastic containers may be prone to deformation at higher temperatures. If a rigid valve cup is used and secured in a sealing manner to the plastic container, for example in accordance with the present invention. even if the container deforms, the container is fixed to the valve cup in such a way that the seal therebetween is not broken. In other words, the seal between the valve cup and container is maintained. Hence, use of a rigid valve cup provides the ability to make use of the advantages of plastic containers, while maintaining the seal between the valve and valve cup. However, the valve cup is advantageously also made of a plastics material for the same reasons as given above.
Preferably, therefore, the valve cup is either formed from a second plastics material or includes a lining formed from the second plastics material.
Semi-crystalline polyesters have a greater degree of crystallinity when compared to more amorphous polyesters and they do not deform when exposed to temperatures greater than 50° C. Crystallized PET (CPET), PBT, PEN, and PEN/PET copolymers are or can be semi -crystalline polyesters. These materials are particularly advantageous for their other properties in packaging and not just the rigidity at elevated temperatures. However, any polyester that can be semi-crystalline and does not deform to a suitable degree at large temperatures may also be used as the semi-crystalline material. Moreover, any blend of CPET, PBT, PEN, and PEN/PET may be used as the second plastic material. In preferred embodiments, the second plastics material is selected from the group consisting of: crystallized PET, PBT, PEN, PEN/PET copolymers, POM, acrylonitrile, polypropylene, or a blend of any of the foregoing.
Use of an adhesive layer to form a seal, in particular when the adhesive layer is formed from a cyanoacrylate adhesive and advantageously when it comprises ethyl cyanoacrylate, has been found to provide an adequate seal when the container is pressurized up to pressures of 13 bar. However, typically the pressures used are lower than this and the internal volume of the container between the inside wall of the container and the outside surface of the bag is usually pressurized at up to 7 bar and in some embodiments between 1 and 3 bar inclusive.
Also, it has been found that a seal formed from such an adhesive layer is maintained when the system is exposure to temperatures greater than the 50° C. regulations and even to temperatures in excess of 70° C.
Preferably, the adhesive layer is applied either around the periphery of the valve cup or around the opening of the neck of the container by rotating the valve cup and/or the container relative to an adhesive dispenser comprising a dosing device.
The valve 50 is shown in detail in
The dispensing tip 54 may have any cross-sectional shape but is preferably cylindrical. The dispensing tip 54 may also include an upper channel 55 that defines a hollow inner portion of the dispensing tip 54. A through hole 56 may be provided at a lower portion of the dispensing tip 54. In
The plunger 53 may be provided so as to slide in the direction of the common central axis. The plunger 53 may be biased to a closed position by a spring (not shown) disposed in the hollow portion of the main body 52 and communicating with receiving parts, such as perpendicular flanges, of the plunger 53.
Optionally, a bag 100 (see
The valve 50 is supported by the valve cup 10. In the example of
The valve main body 52 may be supported by second inner projections 14 that, in
The seal member 60 is preferably sized so as to surround the outer diameter of the dispensing tip 54 and cover the through hole 56 in the closed position, as seen in
When assembling the valve 50 and valve cup 10, the seal member 60 may be inserted into the lower region of the valve cup 10 defined by the second inner projections 14, or the seal member 60 may be positioned on top of the valve main body 52. In any case, when the valve 50 is threaded into the valve cup 10 such that the dispensing tip 54 passes through the central opening 11, the second inner projections 14 may hold the valve main body 52 in place. In some examples, the second inner projections 14 may include raised portions 15 that snap fit into corresponding receiving portions provided in the valve main body 52.
The structure of the valve cup 10 is not particularly limited.
The inverted U-shaped receiving portions 16 may define a space wherein the inner surfaces of the inverted U-shaped receiving portions 16 may contact the lip portion 38 of the container 30 when the valve cup 10 is attached to the container 30. The innermost surface of the inner surfaces may define a diameter d3 of the valve cup 10 which may be equal to or less than the inner diameter of the opening 32. In one example configuration, the diameter d3 may be 24.8 mm, but the diameter d3 is not limited to this value.
In some configurations of valve cup 10, as shown in
In the configuration of valve cup 10 shown in
The polyester lining 61 may be formed from any polyester, but is preferably formed from PET. When the valve cup 10 is formed of a metal, i.e., aluminium, or other rigid material, the structural rigidity of the valve cup 10 at temperatures greater than 50° C. is ensured by the structural rigidity of the metal or rigid material. In other words, the metal or rigid material does not deform at temperatures greater than 50° C. This means that the valve cup 10 may reliably hold and seal the valve 50.
As seen in
The polyester lining 61 does not have to be formed from the semi-crystalline polyesters but in some cases, to prevent deformation of the polyester lining 61 that may lead to detachment from the valve cup 10, the polyester lining 61 may be formed from the semi -crystalline polyesters.
In another configuration of valve cup 10 as shown in
The inverted U-shaped receiving portions 16 may have a height h1 than is greater than the height of the lip portion 38 such that the lip portion 38 is completely contained within the inverted U-shaped receiving portions 16. This configuration is seen in
The section may also be provided with a number of enforcing members or portions 18 that extend from the inverted U-shaped receiving portions 16 to the outer side of the inverted portions 13. This may aid in increasing the structural rigidity of the valve cup 10 while also reducing production costs and material consumption.
As mentioned above, the valve cup 10 is configured to be attached to the container 30. In
A seal formed by an adhesive layer 70 is provided between the valve cup 10 and the neck 36. In this embodiment, the valve cup 10 and the neck 36 define contiguous surfaces 71 and 72 respectively between which the seal formed by the adhesive layer 70 is located. The adhesive layer 70 is preferably formed by a cyanoacrylate adhesive, in particular an adhesive comprising ethyl cyanoacrylate. The adhesive layer 70 forms a band around the whole of the periphery of the surface 71 of the valve cup 10 and bridges the small gap between the surfaces 71 and 72, which is preferably as small as is possible whilst still allowing for the push- or snap-fitment of the valve cup 10 to the container 30.
Preferably, at least the neck 36 of the container 30 but advantageously the whole container 30 is formed from a plastics material, in particular a polyester. Advantageously, the container 30 is formed from polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). It should be appreciated, however, that the material of the container 30 is not limited to PET or PEN but may be any suitable polyester and may also be formed of any of the semi -crystalline polyesters described below that may be used in manufacture of the valve cup 10. Specifically, the neck 36 of the container 30 may preferably be formed from such a semi -crystalline polyester.
The valve cup 10 is also preferably made from a plastics material, in particular one that is rigid, such as a semi-crystalline polyester. In this way the structural rigidity of the valve cup 10 can be ensured beyond the regulation 50° C. owing to its higher degree of crystallinity than the plastics container 30. In some cases, the degree of crystallinity may be greater than 35%, and preferably greater than 38% when measured using differential scanning calorimetry (DSC). DSC is a well-established method for measuring thermal properties of materials and is not explained further herein.
One material that can be used for the valve cup 10 of the present invention is crystallised PET (CPET). PET can either be amorphous or semi-crystalline, depending on how it is processed. Typically, PET can be injection moulded using a suitable mould (e.g., a valve cup). When a standard cycle time is used, the resulting PET product is completely amorphous. A semi-crystalline plastic is one that displays crystalline structures but also amorphous regions. When heated, the amorphous regions can transition from a hard and brittle state to a rubbery, soft, and elastic state; the temperature at which this occurs is known as the glass transition temperature. In a semi-crystalline plastic, the rigidity of the plastic is proportional to the degree of crystallinity, which essentially defines the percentage of the plastic that exhibits crystalline structures. Because the crystalline structures do not undergo the transition from hard to rubbery states, the crystalline structures keep their shape and thus can maintain the rigidity of the semi -crystalline plastic even when the amorphous regions do make the transition at the glass transition temperature.
However, other rigid plastics materials may be used to form the valve cup and preferably these materials are selected from the group consisting of: crystallized PET, PBT, PEN, PEN/PET copolymers, POM, acrylonitrile, polypropylene, or a blend of any of the foregoing.
It should also be appreciated than many other polyesters or polyester blends may be used provided that they display appropriate rigidity. In one example, a PEN/PET copolymer may be used, wherein the percentage of PEN is relatively low in comparison to the percentage of PET, e.g., between 10-20% PEN for reasons of cost. Other copolymers may be used such as PET/PBT copolymers, or even PET/PBT/PEN copolymers. However, any of PET, PBT, or PEN may also be blended with other polyesters and/or other additives, such as nucleating agents, to form semi-crystalline structures.
In other embodiments, the primary material of the valve cup 10 may be a metal or other rigid material. Preferably, the primary material is aluminium. The structure of the valve cup 10 may be the same as described above.
It should be appreciated that various modifications to the specific structure of the valve cup 10, container 30, and valve 50 may be made while still conforming to the principles of the first example of the invention.
In accordance with the second aspect of the present invention an example of a method of assembling the dispensing system using valve cups 10 or container 30 as described above is now given with particular reference to
Once the bag 100 is securely attached to the valve 50, the bag 100 may be folded to reduce the footprint thereof. As shown in
The folding may be performed in any manner so as to reduce the footprint of the BoV and allow insertion into the container 30. In one embodiment, the flat bag 100 is rolled around the axis of the valve 50 and valve cup 10 such that the bag 100 is in a spiralled configuration centred on the axis of the valve 50. In another embodiment, the bag 100 may be folded in a concertina. In both cases, the BoV is preferably provided with a suitable footprint.
In contrast to known methods, the BoV need not be provided with a containing sleeve or tape to retain the BoV in the folded configuration. Rather, the folded BoV is inserted directly into the container 30, as is shown in
Once partially inserted, the inner region of the container 30 may be filled with gas, preferably a propellant gas. Suitable propellant gasses are known in the art and are not discussed further herein. The method used is preferably undercup gassing, which essentially means that the gas is passed under the valve cup 10 and into the region between the bag 100 and the inner volume of the container 30. In the present invention, the inner volume of the container 30 may be pressurized to a pressure between 1 to 3 bar, preferably 1.5 to 2.5 bar.
Once pressurization of the container 30 is complete, the adhesive layer 70 is applied either around the periphery of the valve cup 10 to the surface 71 or to the surface 72 around the opening 32 of the neck 36 of the container 30. In particular, the adhesive layer 70 is applied to one of the surfaces 71 and 72 of the valve cup 10 and the neck 36 but not to both. Preferably, the adhesive layer 70 is applied to the surface 71 of the valve cup 10 as shown in
In some methods, prior to application of the adhesive layer 70, the surfaces 71 and 72 of the valve cup 10 and the container 30 are cleansed so that they are clean and free from greases. A suitable solvent may be used for this purpose and allowed to dry prior to application of the adhesive. Alternatively or in addition, a suitable adhesive primer or activator may be applied either around the periphery of the valve cup 10 to the surface 71 or to the surface 72 around the opening 32 of the neck 36 of the container 30 immediately prior to application of the adhesive. Use of such a primer or activator may increase the bond between the valve cup 10 and the container 30 and there provide a stronger seal between them.
As described above, the adhesive layer 70 is preferably formed by a cyanoacrylate adhesive, in particular an adhesive comprising ethyl cyanoacrylate and is applied as a band around the whole of the periphery of the surface 71 of the valve cup 10. In should be appreciated that only a small quantity of such an adhesive is required to produce a seal between the contiguous surfaces 71 and 72 of the valve cup 10 and the container 30. As the bonding gap between these surfaces 71, 72 is small, typically less than 1 g of the adhesive is required to be employed.
As curing of cyanoacrylate adhesives commences immediately and a strong bond is formed very quickly in a matter of seconds, the next step of the method must take place immediately after the adhesive layer 70 has been applied. This involves pressing the valve cap 10 and therefore the BoV into the opening 32 defined by the neck 36 of the container 30 as shown in
In a preferred configuration, the valve cup 10 is provided with the inverter U-shaped receiving portion 16 and the container 30 is provided with the lip portion 38. Thus, the BoV may be pressed into the container 30 until the lip portion 38 of the container 30 abuts the inverted U -shaped receiving portion 16 and the surfaces 71 and 72 lie contiguous with one another.
In a more preferably configuration, the inverted U-shaped receiving portion 16 comprises the projections 17, 77 which are adapted to engage in a snap-fit manner with the underside of the lip portion 38. In this way, when the valve cup 10 is pressed onto the lip portion of the container 30, the U-shaped receiving portion 16 may deform slightly to allow the projections 17, 77 to pass over the lip portion 38 and subsequently return to their resting state once the projections 17, 77 have passed over the lip portion 38. Securing the valve cup 10 in this way assists in retention of the valve cap 10 in the opening 32 of the neck 36 during curing of the adhesive layer 70 otherwise pressure may have to be retained on the valve cap 10 until adequate curing of the adhesive layer 70 has occurred to retain the valve cap 10 in position.
It is known, however, that cyanoacrylate adhesives cure quickly at ambient temperatures between 20° C. and 25° C. and at normal relative humidities, typically those of at least 35% and preferably those of 50%, and typically an initial curing time of 10 seconds will be sufficient to retain the valve cap 10 in place in the container if a cyanoacrylate adhesive is used. Preferably, however, the adhesive layer 70 is allowed to cure for up to 72 hours in order to develop a high tensile strength that may, for example, be in excess of 13.0 N/mm2.
As cyanoacrylate adhesives require humidity in the surrounding environment to cure, no special conditions are required but it may be appropriate for some or all of the steps of the method to be performed in a sealed environment.
Once the valve cap 10 has been pressed into the container 30 and initial curing of the adhesive layer has taken place, the dispensing system 1 is assembled but further assembly steps may be possible, such as adding a protection overcap 120 to cover the exposed part of the valve 50 as in
Once the adhesive layer 70 has fully cured, the assembled dispensing system 1 may then be transported to various consumers to be filled with a variety of different products. To fill the dispensing systems 1, the fluid medium to be dispensed is passed through the valve 50 into the bag 100, i.e., via upper channel 55, through hole 56, and lower channel 57. The pressure in the container 30 increases as the bag 100 fills with the fluid medium. Preferably, the pressure increases to around 6 to 8 bar, preferably 6.5 to 7.5 bar. This increase in pressure aids in dispensing the fluid medium when the valve 50 is actuated by a user.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/063692 | 6/15/2016 | WO | 00 |
