WO2016203150A1

WO2016203150A1 - Moisture-absorbing tablet releasing a volatile active substance

Info

Publication number: WO2016203150A1
Application number: PCT/FR2016/051445
Authority: WO
Inventors: Valérie VENET; Jacques Brosse
Original assignee: Eurotab
Priority date: 2015-06-15
Filing date: 2016-06-15
Publication date: 2016-12-22
Also published as: EP3307421A1; FR3037257B1; FR3037257A1

Abstract

The present invention concerns a moisture-absorbing tablet (10) comprising a compacted composition (11) comprising a desiccant, characterised in that it comprises a solid gel (12) adhered directly to the compacted composition and comprising at least one volatile active substance, at least one gelling agent and optionally at least one curing agent. The present invention also concerns a method for preparing such a moisture-absorbing composition and a device for diffusing a volatile active substance in a homogeneous and non-decreasing manner comprising said tablet.

Description

ABSORBENT TABLEBOARD WITH FREE MOISTURE

A VOLATILE ACTIVE SUBSTANCE

FIELD OF THE INVENTION

The present invention relates to a moisture absorbent pad diffusing a volatile active substance. The present invention also relates to a method for preparing such a moisture absorbent pad and a device comprising said tablet for diffusing a volatile active substance in a homogeneous and non-degressive manner.

STATE OF THE ART

Remediation of a living space, such as rooms in a house, a caravan, a boat, a cupboard or a linen closet, becomes more and more important as consumers search for more and more of a sensation of well-being with the products they use daily.

Absorbent moisture compositions are already known in the prior art.

EP 1 426 105 relates to a moisture-absorbing material intended for use in a moisture-absorbing device, this material comprising a hygroscopic agent capable of absorbing moisture from the air and transforming it into brine, characterized in that it is in the form of a compact block comprising at least two layers. The block shape makes it possible to handle the product more easily without risk of it breaking up and to simplify the laying of said material in the moisture absorbing device. In addition, the volume occupied by the compact block is smaller than that occupied by the granules for the same amount of material, which makes it possible to reduce the cost of storage. The hygroscopic agent used contains at least 50% CaCl ₂ salt or a salt of MgCl ₂ or a mixture of a salt of CaCl ₂ and MgCl ₂ .

The international application WO 2012/066150 describes an equipment consisting of a holding device for holding a cylindrical tablet containing a desiccant, preferably calcium chloride, capable of absorbing moisture from the air and transforming it into brine and a collection container disposed below the shelf holding device. The tablet has an annular cylindrical shape and has a specific surface that increases the air contact surface and thus improve the moisture absorption efficiency. The equipment contains a ventilation system which allows a better air circulation and thus to improve the efficiency of absorption.

The moisture absorbing tablets described in the prior art contain generally desiccants such as calcium chloride, which are highly corrosive and reactive ingredients. The combination of a moisture absorbing pad with a composition comprising a volatile active substance is therefore difficult to envisage.

Patent FR 2 794 994 relates to a hygroscopic perfuming composition consisting of a mixture comprising a desiccating agent, preferably calcium chloride, and perfume microcapsules. The composition may optionally comprise an organic dye. The walls of the perfume microcapsules are constituted by a film-forming agent. The microencapsulated perfume is released as the moisture of the air is absorbed by the desiccant. The product described in this invention does not allow the homogeneous and progressive release of the perfume because as the tablet absorbs moisture from the air to turn into brine, perfume microcapsules fall into the container of collection including brine and thus can not release the fragrance. This invention therefore does not allow to release the perfume homogeneously since the release of the fragrance fades over time.

EP 2,065,060 discloses a moisture absorbent tablet comprising a desiccant and a cavity on one side of the tablet for inserting a device for perfuming and sanitizing the air. The surface of the device which is in direct contact with the tablet is provided with an impermeable membrane so that the liquid contained in the device can not come into contact with the desiccant, nor migrate into the tablet. The surface of the device in contact with the air is provided with a permeable membrane for gradually releasing the perfume. One of the disadvantages of this product is the risk of piercing the membrane containing the liquid contained in the device. The liquid contained in the device can then flow into the brine thus causing the stop of the release of the perfume. The process for preparing this product is also more difficult and more expensive.

SUMMARY OF THE INVENTION An object of the present invention thus relates to a moisture absorbent pad having a compacted composition comprising a desiccant, characterized in that it comprises a solid gel adhering directly to the compacted composition and comprising at least one substance. volatile agent, at least one gelling agent and optionally at least one curing agent.

A second object of the present invention relates to a method for preparing a tablet according to the invention comprising the following steps:

a) compacting the composition comprising the desiccant, preferably by direct compression;

b) depositing on at least a portion of the surface of the compacted composition obtained in step a), the composition to be gelled comprising the at least one volatile active substance, the at least one gelling agent and optionally at least one a hardening agent;

c) allowing the composition to be gel to dry until a solid gel adhering to said compacted composition is obtained.

Finally, a third subject of the invention relates to a moisture absorbing device comprising a grid placed on a collection tank, characterized in that it comprises at least one absorbent moisture pad according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION The subject of the present invention is a moisture absorbent pad releasing at least one volatile active substance, such as a sanitizing substance or a perfume, by means of a gel deposited on the surface of the tablet or in one or more slots in the tablet. The present invention therefore makes it possible to absorb the humidity of the air and to release in a homogeneous and non-degressive manner at least one volatile active substance in a habitable space in which it is disposed.

The absorbent moisture composition according to the present invention makes it possible to propose a solution to the various disadvantages encountered in the prior art. The absorbent moisture composition according to the present invention allows a homogeneous and non-degressive release of at least one volatile active substance, such as a sanitizer or a perfume, over time. The gel deposited directly in contact with the compacted composition is not damaged by the absorbing agent. In addition, the system proposed in the present invention ensures that the gel never comes into contact with the brine and the volatile active substance present in the gel never flow into the brine even if the gel is damaged.

The subject of the present invention is mainly a moisture absorbent tablet comprising a compacted composition comprising a drying agent, characterized in that it comprises a solid gel adhering directly to the compacted composition and comprising at least one volatile active substance, at least one gelling agent and optionally at least one curing agent.

According to a particular embodiment, the solid gel is disposed on the surface of the tablet and / or in one or more slots in the tablet.

According to a particular embodiment, the tablet comprises several gels different, ie including in particular one or more volatile active substances or a different dye. These different gels can be deposited on the surface of the tablet or in the different housing.

According to a particular embodiment, at least one housing enclosing the solid gel opens on the surface of the compacted composition.

The mass of gel deposited on the tablet is preferably between 0.1 and 300 g, advantageously between 0.5 and 300 g, especially between 0.5 and 50 g.

The tablet according to the invention therefore consists of two parts: a compacted absorbent moisture composition comprising a desiccant and a gel comprising at least one volatile active substance deposited directly in contact with said compacted composition.

Surprisingly, no reactivity or corrosion of the gel is observed, despite its direct contact with the desiccant, of a corrosive nature, present in the compacted composition.

Moisture absorbing tablets described in the prior art generally contain desiccants such as calcium chloride, which are highly corrosive and reactive ingredients. The combination of a moisture absorbing pad with a composition comprising at least one volatile active substance is therefore difficult to envisage.

Characterization of the gel:

The gel according to the invention comprises at least one volatile active substance, at least one gelling agent and optionally at least one curing agent.

For the purposes of the present invention, the term "volatile active substance" means an active substance or a mixture of active substances capable of volatilizing on contact with air. The volatile active substance may also comprise one or more solvents, such as paraffins, isoparaffins, hydrocarbons, glycolic ethers, glycolic ether esters, esters or ketones. The use of a solvent can be useful for obtaining a monophasic liquid medium or for modulating the rate of evaporation of the volatile substance in the air.

The volatile active substance is preferably chosen from fragrances, deodorants, bactericides, insecticides, animal or insect repellents, attractants from animals or insects, essential oils and mixtures thereof, in particular from perfuming substances. , deodorants and insect repellents, particularly preferably the volatile active substance is a perfume.

For the purposes of the present invention, the term "perfuming substance" is intended to mean a perfuming ingredient, also called perfume, which is of common use in the food industry. perfumery, namely a compound which is used as an active ingredient in perfume compositions or scented articles to impart a hedonic effect in its surroundings. In other words, such an ingredient, to be considered as a perfuming substance, must be recognized by those skilled in the perfume industry as being capable of conferring or modifying in a positive or pleasant manner the odor of a composition or a product. In addition, this definition also includes compounds that do not necessarily have an odor, but are capable of modulating the odor of a perfume composition or scented product and, therefore, alter a user's perception of the smell of such a composition or product.

The skilled person may select the fragrance substance to be incorporated into the gel on the basis of his general knowledge, depending on the use, the application and the olfactory effect envisaged. The perfuming substance may be chosen from the compounds alcohol, aldehydes, ketones, esters, ethers, acetates, nitriles, terpene hydrocarbons, heterocyclic or sulfurous nitrogen and essential oils, preferably from liquid hydrocarbon derivatives and essential oils. The perfume substance may be natural or synthetic. Many fragrance substances are listed in S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, New Jersey, USA, or one of its more recent versions. For the purpose of the present invention, the term "deodorant substance" is intended to mean a substance capable of neutralizing and / or masking the bad odors, that is to say capable of reducing the perception of the bad odor or the odor unpleasant to the human nose by neutralizing and / or masking said odor. In a particular embodiment, these compounds have the ability to react with compounds known to cause odors. The reactions result in a reduction of the concentration in the air of the compounds responsible for the bad odors and the consequent reduction of the perception of the bad smell. The deodorant substances are known to those skilled in the art and may, for example, be chosen from chitosan, starch-based odor control substances and esters, esters or cyclic esters chosen from acetate of isomentyl, isomentyl propionate, isomentyl isobutyrate, isomentyl butyrate, isomentyl crotonate and mixtures thereof.

For the purposes of the present invention, the term "bactericidal substance" is intended to mean a substance capable of killing bacteria and / or of preventing bacterial proliferation. The bactericidal substances are known to those skilled in the art and may, for example, be chosen from parabens, benzyl alcohol, benzalkonium chloride, chlorhexidine digluconate, leukine, glucose oxidase and mixtures thereof. For the purposes of the present invention, the term "insecticidal substance" means a substance capable of killing insects, their larvae and / or their eggs. The nature of the insecticidal substances depends on the target insect and the desired action. The insecticidal substances are known to those skilled in the art and may, for example, be selected from organophosphorus compounds, carbamates, synthetic pyrethroids, organochlorines, benzoylureas, neonicotinoids, sulphones, sulphonates, formamidines, carbinols, and their mixtures.

For the purpose of the present invention, the term "repellent substance for animals or insects" means a substance capable of killing insects, their larvae and / or their eggs. The nature of the repellent substances of animals or insects depends on the animal / insect concerned and the desired action. The insect repellant substances are known to those skilled in the art and may for example be chosen from citronella, dimethyl phthalate, N, N-dimethyl-m-tolumide, dimethylphthalate, ethyl hexanediol, and the like. ethylbutylacetylaminopropionate, diethylmethylbenzamide, diethyltoluamide, piperidine and mixtures thereof. The animal repellent substances are also known to those skilled in the art and may, for example, be selected from bitter substances and / or astringent and / or anti-palatable, such as phosphoric acid, picric acid or sulfuric acid, and mixtures thereof.

For the purposes of the present invention, the term "attractive substance for animals or insects" is intended to mean a substance that is palatable to the animals or insects concerned.

The volatile active substance can also be an essential oil or a mixture of essential oils. Essential oils are known to the person skilled in the art who will know how to choose and / or combine them according to the properties envisaged: insecticide, bactericide, olfactory, attractive or repellent of animals or insects, etc., based on his general knowledge.

Those skilled in the art can easily rely on their general knowledge to prepare a volatile active substance having the desired effects and can be incorporated into a gel.

In the context of the present invention, said gel preferably comprises 0.1 to 95% by weight, advantageously 5 to 90% by weight, more preferably 40 to 70% by weight of the volatile active substance, relative to the total weight of the gel.

In addition, the gel preferably comprises 0.5 to 95% by weight, advantageously 10 to 60% by weight, more preferably 20 to 40% by weight, gelling agent (s), relative to the total weight gel. In particular, the gelling agent is a polymer capable of forming a gel. The gelling agent is advantageously chosen from celluloses, modified celluloses, natural gums, gelatin, natural or modified starches, alginates, carrageenans, agar-agar, polyamide resins, gelling polymers such as PEG and acrylic polymers (eg dioxalized acrylic polymers), polyvinylalcohol (PVA), and mixtures thereof.

The gelling agent preferably used in the context of the present invention is chosen from polyamide resins, such as the products of the CrystaSense IM® range and in particular CrystaSense IM700® and CrystaSense IM800® offered by Croda. In particular, the gelling agent is a mixture of CrystaSense IM700® and CrystaSense IM800®. In a particular embodiment, the gel comprises 3 to 15% CrystaSense IM700® and 15 to 30% CrystaSense IM800®.

In particular, the gelling agent is chosen so as to obtain a fast gel setting time, that is to say less than 6 hours, preferably less than 2 hours, more preferably less than 1 hour. It is important that the setting time of the gel be fast to avoid any migration of the composition to be gelated through the absorbent pad of moisture and any reactivity with the desiccant included in the tablet.

By "gel setting time" is meant, in the sense of the present invention, the time required for the composition to gel dry and solidifies to give a solid gel. It is considered that the gel is dry when it no longer sticks to the finger (touch test).

In addition to choosing the gelling agent, a person skilled in the art may opt for the addition of a hardening agent to obtain a fast setting of gel.

Thus, in a particular embodiment, the gel preferably comprises 0 to 10% by weight, preferably 2 to 5% by weight, of curative agent (s), relative to the total weight of the gel. The curing agent is, in particular, chosen from aliphatic polyisocyanates, epoxy resins, polymer crosslinking agents such as glyoxal. Preferably the curing agent is a hexamethylene diisocyanate polymer. There may be mentioned, for example, the products of the DESMODUR® range, such as DESMODUR N 3300® (homopolymer 1,6-hexamethylene diisocyanate), marketed by the company Bayer.

Preferably, the gel according to the invention is a non-aqueous gel, this in order to avoid any reactivity of the desiccant with the gel or the migration of water in the tablet resulting in a reactivity of the desiccant.

For the purposes of the present invention, the term "non-aqueous gel" means a gel obtained from a composition to be gelled which does not comprise water.

In a particular embodiment, the gel according to the invention comprises, by weight, relative to the total weight of the gel: between 0.5 and 95%, advantageously between 10 and 60%, more advantageously between 20 and 40%, by weight of one or a mixture of gelling agents, in particular chosen from polyamide resins;

between 0.1 to 95% by weight, advantageously 5 to 90% by weight, more preferably 40 to 70%, of at least one volatile active substance, preferably a fragrancing substance, a deodorizing substance or an insect repellent substance , more preferably a perfuming substance; and

between 0 and 10% and preferably between 2 and 5% of curing agent, in particular hexamethylene diisocyanate.

The gel may further comprise one or more additional additives selected from organic solvents compatible with CaCl ₂ , antioxidants such as polyvinyl alcohol, UV inhibitors and dyes.

In the context of the present invention, the gel is prepared according to the following steps: a) mixing the gelling agent, the volatile active substance, optionally the hardening agent and optionally the additional additives;

b) depositing the liquid gel obtained in step a) on the surface or a part of the surface of the tablet or in one or more housings present on the surface or inside the tablet;

c) Allow to dry until a solid gel is obtained.

Preferably, the setting time of the gel is less than 6 hours, more preferably less than 2 hours, even more preferably less than 1 hour. It may, for example, be between 0.01 seconds and 1 hour, advantageously between 1 second and 30 minutes, more advantageously between 1 second and 10 minutes.

Characterization of the compacted composition:

The compacted composition comprises at least one desiccant.

For the purposes of the present invention, the term "drying agent" is intended to mean a hygroscopic substance capable of absorbing moisture from the air and transforming it into brine.

The desiccant is preferably selected from the salt of CaCl ₂ , the salt of MgCl ₂ , bentonite, sodium sulfate, sodium carbonate, silica gel and mixtures thereof, preferably the desiccant is CaCl ₂ salt.

The amount of desiccant present in the compacted composition for absorbing moisture from the air and transforming it into brine is preferably at least 20% and more preferably at least 20%. 50%> by weight, relative to the total weight of the compacted composition.

The compacted composition according to the invention consists of a set of particles grouped in a compact manner so as to be able to be handled without disintegrating.

Generally the compacted composition according to the invention does not consist solely of desiccant; perfumes, dyes, antiallergics, silica-type mineral fillers, calcium carbonate, lubricants such as calcium stearate or magnesium stearate and many other compounds may also be included in its composition, preferably in a proportion which, in total, is less than 50% by weight, based on the total weight of the compacted composition.

The compacted composition according to the invention may also include a wear indicator. This wear indicator, released when the size of the compacted composition has sufficiently decreased, falls into the brine and informs the user on the state of wear of said block so that it can predict its replacement.

The compacted composition according to the invention may consist of a layer or a stack of several layers which are superimposed on each other, thus forming a uniform and compact block. The layers may be of similar or different compositions, or even similar or different colors.

The compacted composition may have a cylindrical shape with a section having any shape such as a circular, oval, octagonal, or parallelepipedal shape. When the section of the compacted composition is parallelepipedic, typically square or rectangular, the corners of the compacted composition can be curved so that they are less brittle. Each layer has the same section so that the stack they form together is uniform. The compacted composition may also have any other geometrical shape (star, diamond, etc.). One or more housings may be formed in the compacted composition, preferably at least one of these housing opens outwardly. The housing preferably has a minimum diameter of 0.2 cm. Those skilled in the art, with the help of this general knowledge, will be able to adapt the minimum diameter of the housing according to the size of the desired gel.

The compacted composition preferably has a mass of between 1 and 5000 grams, advantageously between 1 and 500 grams, and especially between 100 and 500 grams.

The compacted composition preferably has a strength of between 50 and 5000 Newtons, preferably between 50 and 3000 Newtons, more preferably between 500 and 1500 Newtons.

The compacted composition may in particular be manufactured according to the following preparation method:

a) mixing the components, including the desiccant, to form the compositions corresponding to each of the layers;

b) Pre-compact the composition, in particular by direct compression, for example on rotary presses;

c) optionally, introduce on the first layer the composition of a second layer and then pre-compact as for the first layer;

d) possibly repeat step c) as many times as necessary layers; and e) compacting all the layers, in particular by direct compression, for example on rotary presses, to obtain a compacted composition.

The compacted composition thus obtained is resistant to shocks.

The pre-compression forces used are in particular between 5 and 200 kN, advantageously between 5 and 100 kN and more advantageously between 10 and 80 kN. The compression force used is in particular between 20 and 1000 kN, advantageously between 40 and 600 kN and more advantageously between 150 and 400 kN. The present invention also relates to a process for preparing a moisture absorbent pad releasing at least one volatile active substance as defined above.

Said preparation process comprises the following steps:

a) preparing a compacted composition comprising a desiccant, for example using the method described above; and

b) depositing on the compacted composition obtained in step a), a composition to be gelled liquid comprising at least one volatile active substance, at least one gelling agent and optionally at least one curing agent, in particular a gel composition for obtaining a gel as described above;

c) allowing the composition to be gel to dry until a solid gel adhering to said tablet is obtained.

In a particular embodiment of the invention, said preparation method comprises the following steps:

b) forming at least one housing on the surface of the compacted composition obtained in step a) and depositing therein the composition to be gelled comprising the at least one volatile active substance, the at least one gelling agent and optionally at least one minus a hardener;

d) optionally, depositing, on at least a portion of the surface of the compacted composition obtained in step c), the composition to be gelled and allowed to dry until a solid gel adhering to said compacted composition.

In a particular embodiment of the invention, one or more housings are formed in the tablet and the gel is deposited within this (these) housing (s). Preferably, at least one housing opens outwards.

In the variant where the housing does not open outwards, said housing may be formed in a first layer of compacted composition which will then be covered by a second layer of compacted composition. The tablet thus obtained will then comprise a stack of several layers which are superimposed on each other with housings at least at the interface of one of two layers.

Thus, in a particular embodiment of the invention, said method of preparation includes the following steps:

a) pre-compacting a first composition layer comprising the desiccant, preferably by direct compression;

d) on the first compacted composition obtained in point c), precompacting a second layer of composition comprising the desiccant so that the at least one housing formed on the first compacted composition is located at the interface of two layers; and

e) compacting all the layers, in particular by direct compression, for example on rotary presses, to obtain a compacted composition; f) optionally, depositing, on at least a part of the surface of the compacted composition obtained in step e), the composition to be gelified and allowed to dry until a solid gel adheres to said compacted composition.

In the context of the present invention, it is also possible to deposit, on the surface of the tablet or in different housings formed on the surface or inside the tablet, several different gels, that is to say comprising a different volatile active substance or a different dye.

Depending on the location of the gel (on the surface of the tablet or in one or more housing opening or not to the outside) it will also be possible to delay the release of the volatile substance.

The present invention also relates to a moisture absorbent device for diffusing a volatile active substance in a homogeneous and non-degressive manner, characterized in that it comprises a moisture absorbent pad as defined above.

The present invention also relates to the use of a moisture absorbent pad as defined above in a moisture absorbent device for diffusing at least one volatile active substance in a homogeneous and non-degressive manner.

In particular, the present invention relates to a moisture absorbing device comprising a grid placed on a collecting tank, characterized in that it comprises at least one absorbent moisture pad as defined above.

The moisture absorbing device used in the context of the invention is a commercially available device comprising, for example, a grid placed on a collecting tank intended to recover the brine. The device may further comprise a protective cover including openings for allowing air to enter. The absorbent moisture pad is disposed on the grid or held above the grid with a holding device. When the tablet absorbs moisture from the air, the desiccant turns into brine that flows through the grate into the collection tank.

In the context of the present invention, the skilled person will be able to adapt the size of the solid gel and housing according to the mesh of the grid. For example, the housings formed in the compacted composition will be larger than the mesh of the grid to ensure that the solid gel present on the compacted composition does not cross the grid when the tablet disintegrates. Thus, the gel does not fall into the collecting tank and never comes into contact with the brine produced. In addition, the gel always remains in contact with the air, which makes it possible to maintain the release of the volatile active substance in a homogeneous manner.

DESCRIPTION OF THE FIGURES

FIG. 1 represents an example of a moisture absorbent pad 10 comprising on the one hand a compacted composition 11 comprising a desiccant and, on the other hand, on at least a portion of its surface, a solid gel 12, adhering directly to said compacted composition 11, said gel comprising at least one volatile active substance, at least one gelling agent and optionally at least one curing agent.

The tablet comprises for example for this purpose one or more housing 13 opening on the surface of the compacted composition, wherein the composition to be gelled is poured to form the gel. The composition to be gelled can also be cast directly onto a solid surface of the compacted composition. The shape given to the gel (by the housing or on the surface of the compacted composition) may be variable depending on the desired aesthetic. The compacted composition may also be of any shape.

Moreover, in some embodiments, it may be provided that the shelf comprises inner non-through housing 14, also enclosing a solid gel 12, which is intended to diffuse its volatile active substance when it comes into contact with the air , and therefore with some delay compared to the start of moisture absorption. In this way, for example, the tablet first absorbs the surrounding humidity and, secondly, diffuses the volatile active substance.

FIG. 2 represents an example of a moisture absorbing device 20 comprising a grid 21 placed on a collection tank 22 intended to recover the brine. The device may further comprise a protective cover 23. The absorbent moisture pad 10 is disposed on the grid 21 or held above the grid 21 by means of a holding device 24. The following examples are intended to illustrate the present invention.

EXAMPLES

EXAMPLE 1 Preparation of a gel comprising a volatile active substance according to the invention - Study of the gel setting time and the reactivity of the compacted composition comprising the desiccant

Several gel compositions were prepared according to the following procedure:

1) Add the perfume with the gelling agent (mixture of polyamide resins:

Crystasense IM700® and IM800®) in a beaker;

2) Mix at a slow rate of 100 rpm for 5 minutes;

3) Once the mixture is homogeneous add the hardening agent hexamethylene diisocyanate (Desmodur N3300®);

4) Mix for 20 seconds to disperse the curing agent in the mixture;

5) Apply the gel to the compacted composition and allow the gel time to dry.

Table 1- Composition of prepared gels

The gel setting time and the gel reactivity with the compacted composition were evaluated for each gel composition. The results obtained are summarized in the table above: Table 2: Anal se of el

This study shows that the gel according to the invention does not react with the compacted composition.

This study also shows that depending on the amount and nature of the gelling agent, the gel intake is different. If the gel intake is too long (more than 6 hours) the gel composition migrates into the compacted composition.

Example 2 Study of the Influence of the Presence of Water in the Gel on the Stability of the Compacted Composition

5% water was added in gel No. 3 prepared in Example 1.

Composition of the absorbent moisture pad:

Composition of the gel:

The compacted compositions were put in an airtight fiowpack. This is the fiowpack that is usually used to package moisture absorbent tablets so that they can be stored for several months without reacting with them. the humidity of the air. The compacted compositions were then stored at 25 ° C and 32% relative humidity.

4 days later, a reaction of the compacted composition is observed, demonstrating that the desiccant of the compacted composition has reacted with the water present in the gel. There is a deterioration of the appearance of the tablet at the interface gel / tablet

Example 3 Comparison of the Perfuming Power of a Moisture Absorbing Tablet Containing Perfume Microcapsules and a Moisture Absorbing Tablet with a Perfumed Gel According to the Invention

1. Preparation of a moisture absorbent tablet containing perfume microcapsules according to the prior art

The composition of the moisture absorbent pad containing microcapsules of perfume is as follows:

Table 3: Composition of the tablet according to the prior art

The different compounds are mixed and then pelletized on a rotary press so as to form a tablet of 300 g. The tablet consists of two strictly identical layers. The compression settings used to make the tablet are:

- Pre-compression force: 60 kN

- Compressive force: 250 kN

The tablet therefore contains 4.2 g of perfume microcapsules. 2. Preparation of a moisture-absorbing tablet with a perfumed gel deposited on the surface of the tablet according to the invention

The composition of the compacted moisture absorbing composition is as follows:

Table 4: Composition of the compacted composition according to the invention

Ingredients Percentage of ingredients (%)

Calcium chloride 99.93

Magnesium stearate 0.07

TOTAL 100 The various compounds are mixed and then pelletized on a rotary press so as to form a compacted composition of 300 g. The tablet consists of two strictly identical layers. The compression settings used to make the tablet are:

- Pre-compression force: 60 kN

- Compressive force: 250 kN

A perfumed gel is then prepared. The composition of the scented gel is as follows:

Table 5: Composition of el according to the invention

The perfume, CrystaSense IM 700 and CrystaSense IM 800 are mixed using mechanical agitation at a speed of 100 rpm for 5 minutes. Once the mixture is homogeneous, hexamethylene diisocyanate (Desmodur N 3300) is added. It is important to continue shaking for a few seconds to disperse the Desmodur N 3300 in the mixture. 6 g of perfumed gel is then deposited on the surface of the compacted composition. There is therefore 4.2g of perfume in the compacted composition.

3. Comparative test of the perfuming power

The two tablets prepared in points 1) and 2) contain the same amount of perfume. They are placed in a device comprising a reservoir intended to receive brine. The two devices are then placed in two similar spaces of size, temperature and relative humidity in order to compare the perfuming power of the two tablets. The evaluation of the perfume power was measured by olfactory assessment by 10 people. A score of 0 to 10 is given (0: no smell of perfume detected and 10: strong smell of perfume detected).

The results obtained are noted in the table below: Table 6: Comification of fuming works

The absorbent moisture pad comprising perfumed gel has a perfuming power at t = 0 greater than the tablet with perfume microcapsules.

The perfuming power of the moisture absorbent pad comprising a perfumed gel hardly decreases over time while the perfuming power of the tablet with microcapsules decreases sharply over time.

The perfuming power of the tablet according to the invention is homogeneous and not degressive over time.

Claims

Absorbent moisture tablet (10) comprising a compacted composition (11) comprising a desiccant, characterized in that it comprises a solid gel (12) adhering directly to the compacted composition and comprising at least one volatile active substance, at least one gelling agent and optionally at least one curing agent.

2. The tablet of claim 1, wherein the solid gel (12) is disposed on the surface of the tablet and / or in one or more recesses in the tablet.

3. Shelf according to claim 2, wherein at least one housing (13) enclosing the solid gel opens on the surface of the compacted composition.

4. A tablet according to any one of claims 1 to 3, comprising a plurality of different gels.

5. Tablet according to any one of claims 1 to 4, wherein the desiccant is selected from the salt of CaCl ₂ , the salt of MgCl ₂ , bentonite, sodium sulfate, sodium carbonate, gel of silica and mixtures thereof, preferably the desiccant is the salt of CaCl ₂ .

6. Tablet according to any one of claims 1 to 5, wherein said gel (12) comprises 40 to 70% by weight of the volatile active substance, relative to the total weight of the gel.

7. Tablet according to any one of claims 1 to 6, wherein said volatile active substance is selected from fragrance, deodorant, bactericidal, insecticidal, repellent animals or insects, attracting animals or insects. , essential oils and their mixtures.

Tablet according to any one of claims 1 to 7, wherein said gel (12) comprises 0.5 to 95%, advantageously 10 to 60% by weight, more preferably 20 to 40% by weight of agent ( s) gelling (s), relative to the total weight of the gel.

9. Tablet according to any one of claims 1 to 8, wherein the gelling agent is selected from celluloses, modified celluloses, natural gums, gelatin, natural or modified starches, alginates, carrageenans, agar-agar, polyamide resins, gelling polymers such as PEGs and acrylic polymers, polyvinylalcohol (PVA), and mixtures thereof.

A tablet according to any one of claims 1 to 9, wherein said gel (12) comprises 0 to 10% by weight, preferably 2 to 5% by weight, of curing agent (s), by relative to the total weight of the gel.

The tablet according to any of claims 1 to 10, wherein the curing agent is selected from aliphatic polyisocyanate, epoxy resins, polymer crosslinking agents such as glyoxal, preferably the curing agent is hexamethylene. diisocyanate.

12. A process for preparing a tablet (10) as defined in any one of claims 1 to 11 comprising the following steps:

b) depositing on at least a portion of the surface of the compacted composition (11) obtained in step a), the composition to be gelled comprising the at least one volatile active substance, the at least one gelling agent and optionally the at least one hardening agent;

c) allowing the composition to be gel to dry until a solid gel (12) adhering to said compacted composition is obtained.

13. Absorbent moisture device comprising a grid placed on a collection tank, characterized in that it comprises at least one moisture absorbent pad (10) as defined in any one of claims 1 to 11.