FR3065176B1 - DOSING VALVE FOR FLUID PRODUCT DISPENSER - Google Patents

Abstract

Metering valve for fluid dispenser, comprising a valve body (10) defining a metering chamber (20) in which a valve (30) slides between resting and operating positions, said valve body (10) and or said valve (30) being made by injection molding a material comprising a polybutylene terephthalate (PBT) matrix and glass microspheres dispersed in said PBT matrix.

Description

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

The preferred field of application of such a valve is the pharmaceutical, 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 resting and operating positions. The valve body and the valve are mostly made by molding plastics of the polymer type, such as polyethylene (PE), polypropylene (PP), polyacetal (POM) or polybutylene terephthalate (PBT). However, the metering valves must meet the requirements of reduced tolerances and be of great dimensional stability for their very small components that constitute them. There is also a requirement of perfect cylindricity for these metering valve components, necessary to maintain the sealing points of the valve, despite a pressure of 5 bar that is found in the tank. There are also requirements for excellent mechanical properties for the materials used in the components that make up the metering valves, in particular because of the high level of mechanical stress that may arise in particular when filling the tank through said metering valve and / or when using the metering valve by the patient. Other constraints may also affect the reliability of the metering valves, such as operation with large pressure differentials or abrasion related to the presence of powder.

The injection-molding process is widely used for the production of parts for applications such as packaging, electricity, automotive, cosmetics or consumer goods. This process is also used in the advanced industry such as medical, pharmaceutical, aeronautic or nuclear. The appearance of 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, some defects in appearance can be generated during the production of parts and their control in large-scale production can be difficult. However, the presence of defects, especially on safety parts, can cause malfunctions or fragility of devices such as metering valves. There are different types of defects, especially burrs, canvases, air bubbles, streaks or even incomplete parts.

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

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

The present invention aims to overcome the aforementioned problems.

The present invention also aims to provide such a metering valve for a reliable product distribution, regular and reproducible at each actuation of the dispenser.

The present invention also aims to provide a simple and inexpensive metering valve to manufacture and assemble.

The present invention therefore relates to a metering valve for a fluid dispenser, comprising a valve body defining a metering chamber in which a valve slides between resting and operating positions, said valve body and / or said valve being made 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 level of between 1 and 20% by weight, advantageously between 1 and 15% by weight.

The present invention also relates to a fluid dispenser comprising a reservoir containing fluid to be dispensed, and a metering valve as described above.

Advantageously, said dispenser comprises an HFA gas as a propellant.

These and other features and advantages will appear more clearly in the following detailed description, with reference to the accompanying drawings, given as non-limiting examples, and in which:

FIG. 1 is a schematic sectional view of a metering valve according to an advantageous embodiment,

FIG. 2 is a graph comparing the Young's modulus of PBT alone and with various additives with that of PBT comprising microspheres according to the invention, and

FIG. 3 is a graph comparing the coefficient of friction of PBT alone with that of PBT comprising microspheres according to the invention.

In the description below, the terms "up", "down", "upper" and "lower" refer to the straight position shown in Fig. 1, and the terms "axial" and "radial" refer to the longitudinal axis of the valve shown in FIG.

The metering valve shown in FIG. 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 comprises a valve body 10 extending along a longitudinal axis A. Within said valve body 10, a valve 30 slides between a rest position, which is that shown in 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 fastening element 5, which may be a crimp, screw or snap-on cap, and advantageously with the interposition of a neck seal 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 with the neck seal. This ring may be of any shape, and the example of 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 collar 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 the 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, as is well known.

FIG. 1 shows the valve in the upright storage position, that is to say the position in which the metering chamber 20 is disposed above the tank 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 high valve) and a lower part 32 (also called bottom 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 tank 1, to fill said metering chamber. 20 when, after each actuation of the valve, the valve 30 returns to its rest position under the effect of the spring 8. This filling is done when the device is still in the inverted position of use, with the valve disposed below of the tank.

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 of the 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 thus 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 are in the form of powder. They have a basic pH, which is favorable when we want to limit the interactions with the active ingredients. They can be subjected to a coupling agent surface treatment, selected according to the nature of the matrix, and which allows a better adhesion between the microsphere and the matrix and a better dispersion.

The microspheres of glasses typically have a diameter of between 1 and 2000 μm. In the various tests carried out and described below, glass microspheres of diameter between 3 and 100 μm, with a median diameter of between 10 and 30 μm, were used. These microspheres may be added to the PBT matrix at a level of between 1 and 20% by weight, advantageously between 1 and 15% by weight. 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 to reduce problems during molding; this makes it possible to substantially 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 made, which makes it possible to obtain values of tensile stress or Young's modulus; Figure 2 shows a significant improvement in Young's modulus for PBT with glass microspheres, compared to PBT alone and with respect to PBT with various well-known additives, such as nucleating agent, talc or blowing agent; - Glass microspheres are of mineral origin, they do not bring additional extractables; on the contrary, they have a diluting effect; thus, with a 13% level of glass microsphere in a PBT matrix, a decrease of just over 15% in 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 force applied (normal force); There are two types of coefficient of friction: the dynamic coefficient and the static coefficient; the static coefficient is the coefficient measured at the beginning of the test; it is the force necessary to move the sample on the substrate and initiate the movement; we also speak 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 was to rub a steel ball on a defined material (here PBT, with and without microspheres) to determine a coefficient of friction; the results obtained reproduced in FIG. 3 show that the contribution of the microspheres makes it possible to reduce the coefficient of friction; this allows to consider including a reduction of friction problems in the valves; the microspheres have no impact on the compatibility with the active principles; this has been tested by directly contacting PBT containing microspheres with active ingredients (for example formoterol fumarate), and by measuring by analytical techniques the degradation of these active principles; the tests carried out did not show impact of 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, without departing from the scope of the present invention as defined by the appended claims.

Claims (5)

Claims 1 metering valve for a fluid dispenser, comprising a valve body (10) defining a metering chamber (20) in which a valve (30) slides between resting and operating positions, characterized in that said valve (10) and / or said valve (30) is (are) made by injection molding a material comprising a polybutylene terephthalate (PBT) matrix and glass microspheres dispersed in said PBT matrix. 2, - Valve according to claim 1, wherein said glass microspheres have a diameter of between 1 and 2000 pm, preferably between 1 and 100 pm. 3. - Valve according to claim 1 or 2, wherein said glass microspheres are added to the PBT matrix at a level between 1 and 20% by weight, preferably between 1 and 15% by weight. 4, - fluid dispenser comprising a reservoir (1) containing fluid to be dispensed, characterized in that said dispenser comprises a metering valve according to any one of the preceding claims. 5. - Dispenser according to claim 5, comprising a HFA gas as a propellant. * * *