EP3609809B1 - Dosing valve for a fluid product dispenser - Google Patents

Description

The present invention relates to a metering valve for a fluid dispenser.

The preferred field of application of such a valve is pharmaceuticals, but this type of valve can also be used in other fields, for example cosmetics or perfumery.

The metering valves of the prior art comprise a valve body defining a metering chamber in which a valve slides between rest and actuation positions. The valve body and the valve are mostly made by molding plastic materials of the polymer type, such as polyethylene (PE), polypropylene (PP), polyacetal (POM) or polybutylene terephthalate (PBT). However, metering valves must meet requirements of reduced tolerances and be of great dimensional stability for their very small components which constitute them. There is also a requirement of perfect cylindricity for these metering valve components, necessary to maintain the valve sealing points, despite the 5 bar pressure found in the reservoir. There are also requirements of excellent mechanical properties for the materials used in the components which constitute the metering valves, in particular due to the high level of mechanical stresses which can arise in particular when filling the reservoir through said metering valve and / or when using the metering valve by the patient. Other constraints can also affect the reliability of metering valves, such as operation with large pressure differentials or abrasion linked to the presence of powder.

The injection-molding process is widely used for the production of parts intended for applications such as packaging, electricity, automobiles, cosmetics or consumer goods. This process is also used in high-tech industries such as medical, pharmaceutical, aeronautics or nuclear.

The appearance of the injected parts is a very important criterion, especially for medical applications for which a high level of quality is essential to guarantee patient safety. Thus, certain appearance defects can be generated during the manufacture of parts and their control in large-scale production can prove to be delicate. However, the presence of faults, in particular on safety parts, can cause malfunctions or fragility of devices such as metering valves. There are different types of defects, especially burrs, webs, air bubbles, streaks or even incomplete parts.

These defects can be remedied in several ways, for example by modifying the parameters of the injection-molding process, by modifying the design of the part to be molded, or by adding additives to the polymers to improve their molding performance.

Nucleating agents are the most widely used additives, in particular for removing surface defects. These nucleating agents act by modifying the crystallization kinetics. These nucleating agents can be based on talc or organic products. Other products, such as blowing agents, can also be used. They break down during the molding process to give a foamed structure. They can be based on sodium bicarbonate and sodium citrate.

The documents FR3035382 , WO2012072962 , FR2767801 and DE2734950 describe devices of the state of the art.

The object of the present invention is to overcome the aforementioned problems.

Another object of the present invention is to provide such a metering valve allowing reliable, regular and reproducible distribution of product on each actuation of the dispenser.

Another object of the present invention is to provide a metering valve that is simple and inexpensive to manufacture and to assemble.

The present invention therefore relates to a metering valve for a fluid product dispenser, comprising a valve body defining a metering chamber in which a valve slides between positions. rest and actuation, said valve body and / or said valve being produced by injection molding of a material comprising a polybutylene terephthalate (PBT) matrix and glass microspheres dispersed in said PBT matrix.

Advantageously, said glass microspheres have a diameter of between 1 and 2000 μm, advantageously between 1 and 100 μm.

Advantageously, said glass microspheres are added to the PBT matrix at a rate of between 1 and 20% by weight, advantageously between 1 and 15% by weight.

A subject of the present invention is also a fluid product dispenser, comprising a reservoir containing the fluid product to be dispensed, and a metering valve as described above.

Advantageously, said distributor comprises an HFA gas as propellant gas.

• La figure 1 est une vue schématique en coupe d'une valve doseuse selon un mode de réalisation avantageux,
• La figure 2 est un graphique comparant le Module de Young du PBT seul et avec différents additifs avec celui du PBT comportant des microsphères selon l'invention, et
• La figure 3 est un graphique comparant le coefficient de frottement du PBT seul avec celui du PBT comportant des microsphères selon l'invention.

These characteristics and advantages and others will emerge more clearly during the following detailed description, given with reference to the accompanying drawings, given by way of non-limiting examples, and in which:

• The figure 1 is a schematic sectional view of a metering valve according to an advantageous embodiment,
• The figure 2 is a graph comparing the Young's Modulus of PBT alone and with different additives with that of PBT comprising microspheres according to the invention, and
• The figure 3 is a graph comparing the coefficient of friction of PBT alone with that of PBT comprising microspheres according to the invention.

In the following description, the terms "top", "bottom", "top" and bottom "refer to the upright position shown in the figure. figure 1 , and the terms "axial" and "radial" refer to the longitudinal axis of the valve shown in figure 1 .

The metering valve shown on figure 1 is of the retention type. It is understood, however, that this is only an example, and that the present invention applies to all types of metering valves.

The valve has a valve body 10 extending along a longitudinal axis. Inside said valve body 10, a valve 30 slides between a rest position, which is that shown in figure. figure 1 , and a dispensing position, in which the valve 30 is pressed inside the valve body 10.

This valve is intended to be assembled on a reservoir 1, preferably by means of a fixing element 5, which may be a crimp, screw or snap cap, and advantageously with the interposition of a neck gasket 6. Optionally, a ring 4 can be assembled around the valve body, in particular to reduce the dead volume in the inverted position and to limit the contact of the fluid product with the neck seal. This ring can be of any shape, and the example of the figure 1 is not limiting.

The valve 30 is biased towards its rest position by a spring 8, which is arranged in the valve body 10 and which cooperates on the one hand with this valve body 10, and on the other hand with the valve 30, preferably with a radial flange 320 of the valve 30. A metering chamber 20 is defined inside the valve body 10, said valve 30 sliding inside said metering chamber to allow distribution of the contents thereof. when the valve is actuated.

The metering chamber is preferably defined between two annular seals, a valve seal 21 and a chamber seal 22, in a well known manner.

The figure 1 shows the valve in the upright storage position, that is to say the position in which the metering chamber 20 is placed above the reservoir 1.

The valve 30 has an outlet port 301 connected to an inlet port 302, which is disposed in the metering chamber 20 when the valve 30 is in the dispensing position. The valve 30 can be made in two parts, namely an upper part 31 (also called the top of the valve) and a lower part 32 (also called the bottom of the valve). The lower part 32 is in this embodiment assembled inside the upper part 31. An internal channel 33 is provided in the valve 30 which makes it possible to connect the metering chamber 20 to the reservoir 1, to fill said metering chamber 20 when, after each actuation of the valve, the valve 30 returns to its position. rest under the effect of the spring 8. This filling takes place when the device is still in the inverted position of use, with the valve positioned below the reservoir.

According to the invention, said valve body and / or said valve is (are) produced by injection molding of a material comprising a polybutylene terephthalate (PBT) matrix and glass microspheres dispersed in said PBT matrix.

While the molding of PBT is problematic, with a great variability in crystallinity from one batch to another, the addition of glass microspheres in a PBT matrix makes it possible to control the crystallinity of the material, and therefore to reduce the problems. molding.

The solid glass microspheres are made from glass, advantageously recycled, and have the advantage of not containing free silica or heavy metals. They come in powder form. They have a basic pH, which is favorable when we want to limit interactions with active ingredients. They can be the subject of a surface treatment with a coupling agent, selected according to the nature of the matrix, and which allows better adhesion between the microsphere and the matrix as well as better dispersion.

Glass microspheres typically have a diameter of between 1 and 2000 µm. In the various tests carried out and described below, glass microspheres with a diameter of between 3 and 100 μm were used, with a median diameter of between 10 and 30 μm. These microspheres can be added to the PBT matrix at a rate of between 1 and 20% by weight, advantageously between 1 and 15% by weight.

• lors du moulage, les microsphères permettent de diminuer la variabilité de cristallinité entre les différents lots de matières et ainsi de réduire les problèmes lors du moulage; cela permet notamment de sensiblement diminuer voire supprimer les problèmes de déformations des composants (appelées retassure) et d'améliorer leur stabilité dimensionnelle;
• les microsphères permettent d'augmenter les propriétés mécaniques du matériau dans lequel elles sont dispersées; pour caractériser la résistance mécanique d'un matériau, on réalise des mesures de traction, ce qui permet d'obtenir des valeurs de contrainte à la rupture ou module de Young; la figure 2 montre une amélioration significative du Module de Young pour le PBT avec les microsphères de verre, par rapport au PBT seul et par rapport au PBT avec différents additifs bien connus, tel qu'un agent nucléant, du talc ou un agent gonflant;
• Les microsphères de verre sont d'origine minérale, elles n'apportent donc pas d'extractibles supplémentaires; elles ont au contraire un effet diluant; ainsi, avec un taux de 13% de microsphère de verre dans une matrice PBT, il a été observé une diminution d'un peu plus de 15% des extractibles;
• les microsphères permettent de diminuer le coefficient de frottement; le coefficient de frottement est le rapport de la force de traction (force de réponse permettant la mise en mouvement de l'appareil) sur la force appliquée (force normale); il existe deux types de coefficient de frottement : le coefficient dynamique et le coefficient statique; le coefficient statique est le coefficient mesuré en début de test; c'est la force nécessaire pour déplacer l'échantillon sur le substrat et initier le mouvement; on parle aussi de coefficient d'adhérence; le coefficient dynamique est le coefficient nécessaire pour que le mouvement soit maintenu à une vitesse constante; dans notre cas, nous avons utilisé les valeurs du coefficient dynamique car le système est alors stable et à vitesse constante; le test a consisté à faire frotter une bille d'acier sur un matériau défini (ici le PBT, avec et sans microsphères) afin de déterminer un coefficient de frottement; les résultats obtenus reproduits sur la figure 3 montrent que l'apport des microsphères permet de diminuer le coefficient de frottement; ceci permet d'envisager notamment une réduction des problèmes de frottement dans les valves;
• les microsphères n'ont pas d'impact sur la compatibilité avec les principes actifs; ceci a été testé en mettant en contact direct du PBT contenant des microsphères avec des principes actifs (par exemple du fumarate de formoterol), et en mesurant par des techniques analytiques la dégradation de ces principes actifs; les essais réalisés n'ont pas montré d'impact des microsphères de verre sur cette dégradation.

The addition of glass microspheres in a PBT matrix makes it possible in particular to obtain the following improvements:

• during molding, the microspheres make it possible to reduce the variability of crystallinity between the different batches of materials and thus reduce problems during molding; this makes it possible in particular to appreciably reduce or even eliminate the problems of deformation of the components (called shrinkage) and to improve their dimensional stability;
• the microspheres make it possible to increase the mechanical properties of the material in which they are dispersed; to characterize the mechanical strength of a material, tensile measurements are taken, which makes it possible to obtain values of tensile stress or Young's modulus; the figure 2 shows a significant improvement in Young's Modulus for PBT with glass microspheres, compared to PBT alone and compared to PBT with various well-known additives, such as a nucleating agent, talc or a blowing agent;
• Glass microspheres are of mineral origin, so they do not provide additional extractables; on the contrary, they have a diluting effect; thus, with a level of 13% of glass microsphere in a PBT matrix, a decrease of a little more than 15% of the extractables was observed;
• the microspheres make it possible to reduce the coefficient of friction; the coefficient of friction is the ratio of the tensile force (response force allowing the device to move) to the applied force (normal force); there are two types of coefficient of friction: dynamic coefficient and static coefficient; the static coefficient is the coefficient measured at the start of the test; it is the force necessary to move the sample on the substrate and initiate the movement; one also speaks of coefficient of adhesion; the dynamic coefficient is the coefficient necessary for the movement to be maintained at a constant speed; in our case, we used the values of the dynamic coefficient because the system is then stable and at constant speed; the test consisted in rubbing a steel ball on a defined material (here PBT, with and without microspheres) in order to determine a coefficient of friction; the results obtained reproduced on the figure 3 show that the contribution of the microspheres makes it possible to reduce the coefficient of friction; this makes it possible in particular to envisage a reduction in the friction problems in the valves;
• the microspheres have no impact on the compatibility with the active ingredients; this was tested by bringing PBT containing microspheres into direct contact with active ingredients (for example formoterol fumarate), and by measuring by analytical techniques the degradation of these active ingredients; the tests carried out did not show any impact of the glass microspheres on this degradation.

The present invention has been described with reference to an advantageous embodiment, but it is understood that a person skilled in the art can make any modifications thereto, without departing from the scope of the present invention as defined by the appended claims.

Claims (5)

1. A metering valve for a fluid dispenser, the metering valve comprising a valve body (10) that defines a metering chamber (20) in which a valve member (30) slides between a rest position and an actuated position, the metering valve being characterized in that said valve body (10) and/or said valve member (30) is/are made by injection-molding a material comprising a PBT matrix and glass microspheres dispersed in said PBT matrix.
2. A valve according to claim 1, wherein said glass microspheres have a diameter lying in the range 1 µm to 2000 µm, advantageously in the range 1 µm to 100 µm.
3. A valve according to claim 1 or claim 2, wherein said glass microspheres are added to the PBT matrix at a content lying in the range 1% to 20% by weight, advantageously in the range 1% to 15% by weight.
4. A fluid dispenser comprising a reservoir (1) containing fluid to be dispensed, said dispenser being characterized in that it further comprises a metering valve according to any preceding claim.
5. A dispenser according to claim 4, containing an HFA gas as a propellant gas.

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