DOSING VALVE FOR A FLUID PRODUCT DISPENSER

Abstract

A metering valve for a fluid dispenser, the metering valve having a valve body that defines a metering chamber in which a valve member slides between a rest position and an actuated position, the valve body and/or the valve member being made by injection-molding a material having a PBT matrix and glass microspheres dispersed in said PBT matrix.

Claims

1. A metering valve for a fluid dispenser, the metering valve comprising a valve body that defines a metering chamber in which a valve member slides between a rest position and an actuated position, the metering valve being characterized in that said valve body and/or said valve member 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 m to 2000 m, advantageously in the range 1 m to 100 m.

3. A valve according to claim 1, 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 claim 1.

5. A dispenser according to claim 5, containing an HFA gas as a propellant gas.

Description

[0017] These characteristics and advantages and others appear more clearly from the following detailed description, given by way of non-limiting example, and with reference to the accompanying drawings, in which:

[0018] FIG. 1 is a diagrammatic section view of a metering valve in an advantageous embodiment;

[0019] FIG. 2 is a bar chart comparing the Young's modulus of PBT on its own and with various additives, with the Young's modulus of PBT including microspheres of the invention; and

[0020] FIG. 3 is a graph comparing the coefficient of friction of PBT on its own with the coefficient of friction of PBT including microspheres of the invention.

[0021] In the following description, the terms upper, lower, top and bottom refer to the upright position shown in FIG. 1, and the terms axial and radial refer to the longitudinal axis of the valve shown in FIG. 1.

[0022] The metering valve shown in FIG. 1 is of the retention type. However, it should be understood that this is merely an example, and that the present invention applies to any type of metering valve.

[0023] The valve includes a valve body 10 that extends along a longitudinal axis A. Inside said valve body 10, a valve member 30 slides between a rest position, that is the position shown in FIG. 1, and a dispensing position in which the valve member 30 has been pushed into the valve body 10.

[0024] The valve is for assembling on a reservoir 1, preferably by means of a fastener element 5 that may be a crimpable, screw-fastenable, or snap-fastenable capsule, and a neck gasket 6 is advantageously interposed between the fastener element and the reservoir. Optionally, a ring 4 may be assembled around the valve body, in particular so as to decrease the dead volume in the upsidedown position, and so as to limit contact between the fluid and the neck gasket. The ring may be of any shape, and the example in FIG. 1 is not limiting.

[0025] The valve member 30 is urged towards its rest position by a spring 8 that is arranged in the valve body 10 and that co-operates firstly with the valve body 10 and secondly with the valve member 30, preferably with a radial collar 320 of the valve member 30. A metering chamber 20 is defined inside the valve body 10, said valve member 30 sliding inside said metering chamber so as to enable its contents to be dispensed when the valve is actuated.

[0026] In conventional manner, the metering chamber is preferably defined between two annular gaskets, namely a valve-member gasket 21, and a chamber gasket 22.

[0027] FIG. 1 shows the valve in the upright storage position, i.e. the position in which the metering chamber 20 is arranged above the reservoir 1.

[0028] The valve member 30 includes an outlet orifice 301 that is connected to an inlet orifice 302 that is arranged in the metering chamber 20 when the valve member 30 is in its dispensing position. The valve member 30 may be made of two portions, namely an upper portion 31 (also known as a valve-member top) and a lower portion 32 (also known as a valve-member bottom). In this embodiment, the lower portion 32 is assembled inside the upper portion 31. An internal channel 33 is provided in the valve member 30 that makes it possible to connect the metering chamber 20 to the reservoir 1, so as to fill said metering chamber 20 after each actuation of the valve when the valve member 30 returns to its rest position under the effect of the spring 8. Filling is performed when the device is still in its upsidedown working position, with the valve arranged below the reservoir.

[0029] In the invention, said valve body and/or said valve member is/are made by injection-molding a material comprising a PBT matrix and glass microspheres dispersed in said PBT matrix.

[0030] Although molding PBT is problematic with crystallinity varying greatly from one batch to another, the addition of glass microspheres in a PBT matrix makes it possible to control crystallinity of the material and thus reduce molding problems.

[0031] The solid glass microspheres are made of glass, advantageously recycled glass, and present the advantage of containing neither free silica nor heavy metals. They are in powder form. They have a basic pH, which is favorable when it is desired to limit interaction with the active ingredients. They may be subjected to a surface treatment with a coupling agent, which is selected as a function of the nature of the matrix, and which enables better adhesion between the microsphere and the matrix, and also better dispersion.

[0032] The glass microspheres typically have a diameter lying in the range 1 m to 2000 m. In the various tests performed and described below, glass microspheres were used of diameter lying in the range 3 m to 100 m, with a median diameter lying in the range 10 m to 30 m. The microspheres may be 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.

[0033] Adding glass microspheres into a PBT matrix makes it possible, in particular, to obtain the following improvements: [0034] during molding, the microspheres make it possible to reduce the variability of crystallinity between the various batches of materials, and thus to reduce difficulties during molding; in particular this makes it possible to reduce substantially or to eliminate difficulties of the components deforming, and to improve their dimensional stability; [0035] the microspheres make it possible to increase the mechanical properties of the material in which they are dispersed; in order to characterize the mechanical strength of a material, traction measurements are performed, thereby making it possible to obtain breaking stress values or Young's modulus values; FIG. 2 shows a significant improvement in the Young's modulus for PBT with the glass microspheres compared to PBT on its own, and also compared to PBT with various well known additives, such as a nuclei forming agent, talc, or a foaming agent; [0036] the glass microspheres are of inorganic origin, thus they do not add any additional extractables; on the contrary they have a diluting effect; thus, with a content of glass microspheres of 13% in a PBT matrix, a reduction in extractables of a little more than 15% has been observed. [0037] the microspheres make it possible to reduce the coefficient of friction; the coefficient of friction is the ratio of the traction force (response force enabling the apparatus to move) over the applied force (normal force); two types of coefficient of friction exist: the dynamic coefficient and the static coefficient; the static coefficient is the coefficient measured at the beginning of a test; it is the force necessary to move the sample on the substrate and to initiate movement; the term coefficient of adhesion is also used; the dynamic coefficient is the coefficient necessary for movement to be maintained at a constant speed; in this embodiment, values for the dynamic coefficient are used since the system is thus stable and at constant speed; the test consisted in causing a steel ball to rub against a defined material (specifically PBT, with and without microspheres) so as to determine a coefficient of friction; the results obtained are reproduced in FIG. 3 and they show that adding microspheres makes it possible to reduce the coefficient of friction; in particular, this makes it possible to envisage a reduction in difficulties with friction in valves; [0038] microspheres do not have any impact on compatibility with active ingredients; this has been tested by putting PBT containing microspheres into direct contact with active ingredients (e.g. formoterol fumarate), and by measuring the degradation of the active ingredients using analytical techniques; the tests performed did not show the glass microspheres having any impact on such degradation.

[0039] The present invention is described above with reference to an advantageous embodiment, but naturally any modification could be applied thereto by the person skilled in the art, without going beyond the ambit of the present invention, as defined by the accompanying claims.