FR2872706A1 - System for deodorizing an atmosphere comprises a device for depositing deodorant-releasing microcapsules on a surface - Google Patents

Abstract

System for deodorizing an atmosphere comprises a device for depositing microcapsules on a surface. The microcapsules have walls that can be fractured when trodden upon by people walking on the surface and contain molecules having a deodorizing action when vaporized at ambient temperature. An independent claim is also included for deodorizing an atmosphere using a system as above by projecting the microcapsules onto a textile surface, especially a carpet.

Description

2872706 1

  The present invention relates to the design and construction of a deodorizing system for ambient air with a delay effect.

  This system is intended for the deodorization of ambient air s in all places where such deodorization may be desired, in individuals or in public or public places.

  By deodorization of the air or of the atmosphere is meant any modification of the atmosphere, whether it be the release into the atmosphere of odorous substances such as perfumes, or the purification of the air. 'air. The system according to the invention is applicable to all types of perfumes, whether of natural or synthetic origin.

  According to conventional air deodorization systems, a perfume solution is sprayed into the air. This gives a pleasant odor in the room, but which however has the disadvantage of a short time of remanence.

  In recent years, attempts have been made to obtain deodorization of air with a lasting effect. Formulations containing perfumes with a low saturating tension, or with slow evaporation kinetics, have for example been developed and used to prolong the duration of the odor effect of the ambient deodorizers integrating them. Currently, there are thus on the market of diffusers or long-lasting sprays, or even scented sands. However, these products have a major disadvantage: they are inefficient in places where the air is recycled or air-conditioned, and therefore renewed constantly.

  The object of the invention is to overcome the drawbacks of existing air fresheners, and especially those presented above, by proposing an air deodorizing system which has a delayed effect, that is to say a deferred fragrance release from the moment when the user engages this system, and prolonged in time.

  To this end, the system for deodorizing an atmosphere according to the invention is characterized in that it comprises means for depositing, on a receiving surface, microcapsules with mechanically fracturable walls under the influence of persons walking on this surface. surface, and containing molecules having a deodorizing action by vaporization at the ambient air temperature.

  Microcapsules are particles known in themselves, which have the particularity of having a structure made of a core that may contain molecules of interest to be encapsulated, this heart being surrounded by outer walls impervious to these molecules. The walls of the microcapsules have a certain mechanical strength. Thus, to release the molecules contained in the heart, it is necessary to cause the rupture of the walls, and for this purpose, to exert on them a certain force. They typically have a diameter of the order of one micron (m), from one to several tens of microns.

  In the context of the invention, it is conceivable to encapsulate all kinds of molecules having a deodorizing action. In the preferred embodiments of the invention, it will preferably be perfume molecules, alone or in mixture.

  The microcapsules chosen according to the invention are advantageously such that the material which composes them is chemically inert with respect to the encapsulated substances.

  In the expression "receiving surface" is meant all kinds of surfaces which on the one hand are capable of retaining the microcapsules deposited on them for a certain time, and on the other hand, on which an individual is likely to walk, or to exert pressure, by support by any of its members. Thus, according to the system according to the invention, the microcapsules are intended to be deposited on the ground, in a space to be trampled, or on a seat, a mattress, or on any other support on which one or more individuals go sit, lean, lie down, or otherwise wear their weight or equivalent weight.

  The microcapsules according to the invention thus have the characteristic of being able to be mechanically fractured not only under the stride of people walking on the receiving surface, but also under the weight of persons sitting, or leaning back, or exercising any other similar pressure on this surface.

  The system according to the invention is particularly suitable for depositing microcapsules on a surface made of textile fibers, in particular on a pile surface of the carpet or carpet type. Indeed, the deposited microcapsules penetrate between the hairs, and they are held permanently in the same distribution in which they were deposited. In this case, there is also no risk that a person will slip on the deposited microcapsules, which could occur if the receiving surface was smooth.

  The invention is also applicable for the deposition, on a receiving surface of the bedding type, of molecules with a cosmetic effect, in particular with moisturizing properties.

  When the microcapsules are deposited on the chosen receiving surface, the perfume molecules or the like they contain remain trapped inside their heart, and they do not emit their odor immediately. The microcapsules remain intact as long as no mechanical force is exerted on them. When crush pressure is applied to the walls of the microcapsules, for example by the foot of an individual treading the receiving surface on which the microcapsules have been deposited, there is a rupture of the walls of the microcapsules, resulting in the release of the perfume molecules, which vaporize at room temperature. An odor then spreads in the ambient air. Thus, when microcapsules have been deposited on an entire area, for example over the entire floor area of a room, when a number of the microcapsules deposited are crushed, there is a deodorizing effect of the ambient air. This phenomenon is repeated each time microcapsules are crushed, until all have been.

  In addition, quite advantageously, when vacuuming on a surface on which microcapsules are deposited, there is also a deodorant effect, since the aspirated microcapsules are broken in the fan of the vacuum cleaner. There is then liberation of the perfume which they contained.

  Thus, the system according to the invention advantageously makes it possible to obtain a double delay effect of deodorizing the ambient air a prolonged effect over time, caused by the different successive actions of crushing the microcapsules by the individuals moving in the room , and a more punctual effect, also delayed compared to the initial deposition operation of the microcapsules on the receiving surface, due to the passage of a vacuum cleaner on the latter.

  According to an advantageous characteristic of the invention, the deposition means are means for projecting a dispersion of the microcapsules in an aqueous vehicle.

  This projection deposition mode is particularly suitable for receiving surfaces of the pile surface type, since it favors that the microcapsules, projected towards the surface with a certain speed, penetrate deeply inside the hairs. They are then retained durably, until their wall is broken by a mechanical force applied on them.

  In addition, according to the invention, the microcapsules are advantageously presented in the form of a stable dispersion in the chosen vehicle.

  According to preferred embodiments in industrial practice, the invention has the following additional features, implemented separately or in each of their technically operative combinations.

  By some of these features, the object of the invention is in particular to obtain an effective deodorizing effect by releasing into the atmosphere an odoriferous substance.

  Thus, according to an advantageous secondary characteristic of the invention, the microcapsules are present in the dispersion in a concentration of between 5 and 50% by weight.

  In addition, in preferred embodiments of the invention, the perfume molecules are non-water soluble, and they are present inside microcapsules in pure form, or diluted in a non-water soluble vehicle. Each microcapsule contains in particular 1.10-10 to 1.10-6 I of perfume solution.

  This ensures that, whatever the odor capacity of the particular perfume molecules chosen to be encapsulated, that is to say, trapped in the microcapsules heart, when deposited microcapsules are crushed, for example by a passing individual. the room, it emits an odor that is perceptible by this individual. By the amount of perfume in each microcapsule and by the density of the deposit, it can be ensured that this odor is substantially equivalent in intensity to that which could be released if the perfume was occasionally diffused by means of a conventional deodorant system.

  In addition, a further object of the invention is to ensure that on the one hand the dispersion of microcapsules in an aqueous vehicle is stable, and that on the other hand it is suitable for diffusion projection in a system of the systems type. aerosol.

  Thus, according to an advantageous characteristic of the invention, the dispersion comprises dispersing agents and / or gelling agents in an amount necessary to be stable under temperature conditions of between 0 and 50 ° C., and under pressure conditions of between 1 and 10 ° C. bars.

  In preferred embodiments of the invention, the dispersion comprises dispersing and gelling agents in a concentration of 0.2 to 2% by weight. This ensures that the microcapsules will remain properly dispersed in the solution. It is furthermore quite advantageous in the context of the invention to use agents which have both dispersing and gelling properties, in order to reduce the number of steps necessary for the preparation of the dispersion.

  According to a secondary characteristic of the invention, the dispersion also contains free perfume molecules, that is to say non-encapsulated molecules. These molecules are in particular present in the dispersion in a concentration of between 0.5 and 5% by weight, and especially in emulsion form, or in water-soluble form.

  Thus, when the microcapsules are projected on the receiving surface, the free perfume molecules present in the dispersion are simultaneously sprayed, and an odorous release in the room is immediately produced. This results in a double deodorizing effect: an immediate effect, due to the presence in the dispersion of unencapsulated perfumes, and a delay effect, due to the action of the encapsulated molecules, which are released only after rupture by crushing the walls of the microcapsules.

  In this case, the invention provides that the dispersion also contains protective colloids, such as those which generally consist of compounds of the polyacrylamide-sulfonate, polyvinyl alcohol or polyvinylpyrrolidone type, in a concentration advantageously between 0.degree. , 1 and 1% by weight. These arrangements advantageously make it possible to avoid the occurrence of interference disturbances at the interfaces at the microcapsule / aqueous vehicle and microcapsule / free perfume interfaces.

  In preferred embodiments of the invention, the microcapsules are spherical microcapsules with resin walls of the family of aminoplasts, in particular based on melamineformol. Such microcapsules are for example prepared according to the technique described in WO 01/51197, adapting this technique to the encapsulation of deodorant molecules.

  According to a most advantageous characteristic of the invention, the microcapsules have a diameter of between 10 and 80 m. This is convenient, given the implications of conventional microcapsule manufacturing techniques, to obtain on the one hand that the surface of the microcapsules offered in contact with the stride of people is relatively large, to obtain on the other hand that their wall thickness is relatively small, so that in total, the mechanical strength of the walls is low enough to allow easy rupture of the walls by crushing under the stride of people. When the microcapsules are deposited on the receiving surface, the probability that their wall will break when an individual passes over them is important. This size of the microcapsules is obtained by appropriately choosing the formulation parameters.

  In preferred embodiments of the invention, the microcapsules are presented in aerosol-type packaging, in an enclosure closed by an outward diffusion nozzle, under a blanket of an inert propellant fluid, in particular in the form of a gas. The propellant fluid is advantageously chosen so that it is inert with respect to the aqueous dispersion of microcapsules.

  The diffusion system is advantageously provided to be able to ensure a projection of the dispersion downwards, in particular towards a soil surface. This avoids having to project the dispersion into the atmosphere. This could indeed be particularly dangerous for the occupants of the room, and especially for the user of the system, because according to the invention the dispersion can contain a significant amount of dry extract, which can be up to 50% by weight. weight of dry extract (the dry extract being constituted by the microcapsules), whereas this concentration could cause pulmonary problems to the individuals who would breathe in the corresponding environment.

  In addition, the diffusion system is advantageously designed so that the microcapsules are not damaged upon diffusion to the receiving surface.

  According to an advantageous characteristic of the invention, the propellant gas is a dimethylether gas. This gas has the particular advantage of not reacting with the aqueous vehicle dispersion. However, any other type of gas is also usable.

  In preferred embodiments of the invention, the microcapsules and the propellant are passed through a dip tube to the diffusion nozzle. Microcapsules are admitted into this tube through a lateral inlet port of diameter smaller than the internal diameter of the dip tube.

  Such an embodiment of the diffusion system advantageously makes it possible, when the dispersion is diffused downwards, to form a very regular jet. It also offers the advantage, in connection with the choice of the propellant, not to generate whitish traces on the ground, unlike what could happen with other embodiments of the diffusion system in which would be creates a disruption of the stability of the dispersion during diffusion, and a subsequent agglomeration of the microcapsules in the diffusion nozzle.

  According to a secondary characteristic of the invention, the diameter of the lateral admission orifice is 10 to 80 times greater than the diameter of the microcapsules, and the internal diameter of the diffusion nozzle is substantially equal to that of the orifice. intake.

  This advantageously eliminates the risk that the microcapsules are subjected during diffusion to shear forces strong enough to cause the rupture of their walls. In connection with this characteristic, the invention further ensures that the walls of the microcapsules pre-feel a sufficient mechanical strength not to be fractured during passage through the diffusion nozzle.

  Moreover, quite advantageously, the stability of the dispersion is not disturbed during the passage of the inlet orifice to the diffusion nozzle.

  The conditioning of the dispersion in the aerosol system chosen according to the invention is carried out in a conventional manner per se.

  The invention also relates to a process for the deodorization of an atmosphere which consists, by means of the system according to the invention, of projecting microcapsules enclosing perfume molecules to a textile receiving surface, preferably of the furred surface type, in particular on a carpet on the ground, able to hold the microcapsules that penetrate between the hairs.

  The projection is in particular carried out homogeneously over the entire receiving surface. For example, in a room, it is on the entire floor surface likely to be trampled, that is to say the surface to live, that will be deposited microcapsules. It may also consider placing microcapsules on a chair or a sofa, or on the sheets or blankets of a bed.

  The invention will now be more fully described in the context of preferred features and their advantages, with reference to the single figure which is a schematic representation of a packaging system of a microcapsule dispersion according to the invention.

  A dispersion in an aqueous vehicle of microcapsules trapping perfume molecules is prepared in the following manner.

  Microcapsules according to the invention are synthesized according to the method described in document WO 01/51197, by applying this method to the encapsulation of perfumes, for the particular application aimed at. The various parameters are chosen in particular to obtain microcapsules large enough to allow the rupture of their walls under the effect of crushing by the foot of an individual.

  A perfume emulsion is first made in an aqueous solution. The term perfume here encompasses any molecule or mixture of molecules with odorant properties. The invention also relates to cosmetic molecules, in particular with a moisturizing effect.

  The aqueous solution contains a protective colloid, in particular of the type sold under the trademark Lupasol DVFR, in a proportion of between 10% and 20% by weight, in particular approximately equal to 12% by weight. It also contains an aminoplast resin in a proportion of 10 to 20% by weight, in particular approximately equal to 13% by weight.

  The perfume, which is not water-soluble, is introduced into the solution in liquid form, pure or diluted in a non-water-soluble vehicle, especially in a fatty alcohol. The dilution rate of the perfume is then chosen according to the odor force of the latter, and the deodorization effect that it is desired to obtain. It can vary from 1 to 100% depending on the case.

  The perfume solution is introduced into the mixture in a proportion of between 35 and 50% by weight, in particular approximately equal to 45% by weight. The solution is brought to 45 C. Its pH is between 5 and 7, in particular about 5.5. The emulsion is produced by means of a dispersing disk, whose peripheral speed of rotation is between 2 and 15 m.s-1.

  An acid is then added to the emulsion in order to adjust its pH to a value between 3.5 and 4.5, and especially equal to 4.1. Such an acid may be, for example, formic acid diluted to 10% in an aqueous solution, which will be introduced into the emulsion in an appropriate concentration to obtain the target pH value. The drop in pH causes condensation of the aminoplast resin around the liquid drops of perfume. The solution is kept under the conditions of stirring and temperature exposed above for 30 to 60 minutes.

  The emulsion is then brought to 80 ° C. for 90 minutes with stirring of 2 to 7 m.s.sup.-1 and at a constant pH of between 4 and 4.5. This has the effect of causing the cross-linking of the aminoplast resin around the perfume drops. During this step, a dispersion of melamine and urea and a solution of formic acid are continuously added to the solution. This has the effect of consuming some of the formaldehyde formed during the reaction, both in the solution and in the walls of the microcapsules during the course of formation. Microcapsules with low formaldehyde content are thus obtained, and thus, quite advantageously, potentially less toxic.

  Finally, the finally obtained dispersion is filtered on a filter of the type of the filters known under the trade name Buchner or on a band filter, so as to separate the microcapsules formed from the rest of the solution. The microcapsules thus obtained have a size of between 10 and 80 m in diameter, depending on the formulation parameters chosen and on the speed of the dispersing disc used.

  It is then formed a stable dispersion and capable of being diffused microcapsules thus obtained. For this, the microcapsules are dispersed in an aqueous solution containing surfactants with gelling properties, such as those marketed under the trademarks Laponite RD (synthetic clay), Carbopol (polyacrylic acids), Kelcogel, or Silicagel (spherical particles of silicon dioxide). These agents are introduced in a concentration of between 0.2 and 2% by weight.

  It is also possible to add in the solution free perfumes, that is to say non-encapsulated, in the form of an emulsion or in water-soluble form, in a concentration of between 0.5 and 5% by weight according to the perfume and its fragrant force. .

  In this case, in order to avoid disturbances in the interactions at the microcapsule / water and microcapsule / free perfume interfaces, protective colloids, for example based on polyacrylamide, are added to the dispersion. sulfonate, polyvinyl alcohol, or polyvinylpyrrolidone, at concentrations of between 0.1 and 1% by weight.

  The final concentration of microcapsules in the dispersion is intended to be between 1 and 50% by weight, preferably between 5 and 50% by weight. The dispersion thus obtained is stable under temperature conditions ranging from 0.degree. To 50.degree. C., and pressure conditions of between 1 and 9 bars.

  This dispersion of microcapsules is conditioned in an aerosol type diffusion system.

  The dispersion of microcapsules in an aqueous vehicle is first mixed with various additives, such as emulsifiers (polyacrylic acid, fatty alcohol, polyethylene glycol, polypropylene oligomer and ethoxylated polyethylene, etc.), preservatives, anti-doping agents and the like. -acarants, anti-bacterial agents, odor destroyers, etc., depending on the desired use, in the limit where these additives do not have the effect of destabilizing the dispersion of microcapsules. The mixture of the different ingredients is carried out in a conventional manner, under conditions within the reach of those skilled in the art.

  The conditioning system chosen according to the invention allows diffusion of the microcapsules downwards. This system is shown in the figure in its normal position of use, that is, directed for downward diffusion.

  The system consists of a housing 1 inside which are present two phases 2 and 3. The housing 1 is made of tinplate or aluminum, and it has a conventional capacity for aerosol-type deodorant housings, between 150 and 750 ml.

  The casing 1 is provided with a diffusion head composed of a closing cup of the casing 4, a diffusion nozzle 5 and a plunger tube 6. This diffusion head is conventional in itself, including understood with regard to its operation as a valve. The opening and closing of the valve are ensured, in a conventional manner, by means of a diffuser cover 7, which is for example, as shown in the figure, vertically diffused through a diffusion orifice 8. This embodiment is however not limited to the invention, and any other embodiment for downward diffusion is also within the scope of the invention.

  The lower phase, ie phase 2, which is furthest from the diffusion nozzle 5, consists of a propellant, which is compatible with a solution in an aqueous vehicle and inert with respect to the microcapsules. These include a dimethyl ether gas. In this case, the pressure inside the housing 1 is approximately equal to 3 to 5 bars. At this pressure, the microcapsule dispersion is stable. The other phase, or upper phase 3, consists of the solution containing the microcapsules dispersed in their own aqueous vehicle.

  The microcapsule dispersion is fed into the diffusion head through a side inlet port 9 in the dip tube 6 near the upper end thereof. It then borrows the end portion of the plunger tube 6 to reach the diffusion nozzle 5. The propellant gas is, in turn, led to this nozzle by the plunger tube 6, in which it is admitted through an orifice terminal 10 formed at the lower end of this tube, and of the same diameter as this. When pressed on the diffuser cover 7, the microcapsule solution is pushed by the gas to the nozzle 5, from where it is diffused outwards via the diffuser orifice 8.

  A particular example of the system according to the invention illustrates the relative dimensions of its main elements. The addition of gas is carried out so as to cause effective shearing which favors the formation of a very regular jet.

  The internal diameter of the plunger tube 6 is greater than that of the inlet orifice of the microcapsule dispersion 9. The internal diameter of the nozzle 5 is, meanwhile, substantially equal to that of the intake orifice 9 This nozzle diameter is 10 to 80 times greater than the diameter of the microcapsules. It is preferably between 0.5 and 2 mm, and in particular approximately equal to 1 mm.

  The parameters thus chosen lead to an optimal flowability of the product, the stability of the dispersion is not disturbed during the diffusion, it is avoided to subject the wall of the microcapsules to shearing forces which could cause their early rupture during their passage through the nozzle. In addition, the whitish traces on the receiving surface towards which this jet is directed are not observed to give rise to fears of less well-controlled deposition conditions.

  By means of this diffusion system, the dispersion of microcapsules is projected on a chosen receiving surface, preferably made of textile material, in particular on a pile floor, of the carpet or carpet type. The deposit is preferably carried out homogeneously over the entire surface. An odor emanates immediately in the ambient air, due to the unencapsulated fragrances present in the dispersion. The microcapsules penetrate between the hairs, and lo they are retained there. They remain in place and intact as long as no mechanical effort is exerted on them.

  When an individual walks on the surface, he crushes the microcapsules that are there, causing the rupture of their walls. The perfume that was encapsulated is then released, and an odor emerges in the room. This phenomenon is reproduced each time a part of the deposited microcapsules are trampled. Thus, quite advantageously, there is obtained a deodorization delay effect, which also offers the advantage of occurring only when one or more people are in the room. In addition, if the vacuum is vacuumed on the surface in question, the microcapsules that have not been trampled are broken in the fan of the vacuum cleaner, and there is again a deodorizing effect in the room.

  The foregoing description clearly explains how the invention achieves the goals it has set for itself. In particular, it provides a deodorization system of a delayed and prolonged effect atmosphere, which may further be associated with an immediate deodorizing effect. Nevertheless, the invention is not limited to the modes of implementation which have been specifically described and shown in the figures, but extends to any variant passing through equivalent means.

2872706 15

Claims (13)

  1. Deodorization system of an atmosphere, characterized in that it comprises means for depositing on a receiving surface microcapsules with mechanically fracturable walls under the stride of people walking on said surface, and containing molecules having a deodorizing action by vaporization at ambient air temperature.   2. System according to claim 1, characterized in that said deposition means are means for projecting a dispersion of said microcapsules in an aqueous vehicle.   3. System according to claim 2, characterized in that said microcapsules are present in said dispersion in a concentration of between 5 and 5.0% by weight.   4. System according to one of claims 2 or 3,   characterized in that said dispersion comprises dispersing agents and / or gelling agents in an amount necessary to be stable under temperature conditions of between 0 and 50 ° C., and under pressure conditions of between 1 and 10 bars.   5. System according to claim 4, characterized in that said dispersion comprises dispersing agents and gelling agents in a concentration of 0.2 to 2% by weight.   6. System according to any one of claims 2 to 5, characterized in that said dispersion also contains free perfume molecules, especially in a concentration between 0.5 and 5% by weight, and in that said dispersion 2872706 16 contains protective colloids in a concentration of between 0.1 and 1% by weight.   7. System according to any one of claims 1 to 6, characterized in that said microcapsules are spherical microcapsules with resin walls of the family of aminoplasts, especially based on melamine-formaldehyde, and in that they have a diameter between 10 and 80 m, under a relatively small thickness, so that the mechanical strength of their walls is low enough to allow easy rupture of said walls by crushing under the stride of said people.   8. System according to any one of claims 1 to 7, characterized in that said microcapsules are presented in aerosol type packaging, in a chamber (1) closed by an outward diffusion nozzle (5), under a covering a propellant fluid, especially in the form of a gas.   9. System according to claim 8, characterized in that said propellant gas is a dimethyl ether gas.   10. System according to claim 8 or 9, characterized in that said microcapsules and said propellant fluid are conducted by a dip tube (6) to said diffusion nozzle (5), said microcapsules being admitted into said dip tube (6) by a lateral admission port (9) of smaller diameter than the inner diameter of said plunger tube (6).   11. System according to claim 10, characterized in that the diameter of said lateral admission orifice (9) is 10 to 80 times greater than the diameter of said microcapsules, and in that the internal diameter of said diffusion nozzle (5) ) is substantially equal to that of said inlet port (9).   2872706 17 12. System according to any one of the preceding claims, characterized in that said perfume molecules are non-water-soluble and in that they are present inside said microcapsules in pure form, or diluted in a vehicle also non-water soluble.   13. Process for the deodorization of an atmosphere, by means of a system according to any one of Claims 1 to 12, characterized in that said microcapsules are projected towards a textile receiving surface, preferably of the type with a bristle surface. , in particular on a carpet on the ground, able to retain the microcapsules which penetrate between said hairs.