WO2002047735A1

WO2002047735A1 - Article for controlled release of a volatile organic substance

Info

Publication number: WO2002047735A1
Application number: PCT/FR2000/003515
Authority: WO
Inventors: Louis Michel Jacques Aguadisch; Edouard André Henri BIGOT; André Rudolf Louis COLAS; Guy Jean-Pierre Delpech; Frédéric Fonta; Jean Maurice Eugène MANE
Original assignee: Etablissements V. Mane Fils; Dow Corning France
Priority date: 2000-12-14
Filing date: 2000-12-14
Publication date: 2002-06-20
Also published as: AU2001221854A1

Abstract

The invention concerns an article for controlled and substantially uniform release of a volatile organic substance into the surrounding atmosphere, comprising a silicone elastomer matrix (a) of desired shape wherein is dispersed said volatile substance (b) and an efficient amount of an agent (c) providing compatibility between the volatile substance and the silicone elastomer of the matrix. The invention is characterised in that the compatibilizing agent (c) is an organic solvent having a Hildebrand solubility parameter ranging between 8 and 14 (cal/cm3)1/2 and a vapour pressure ranging between 0.0005 and 0.8 mm of mercury (0.06 and 105 Pa) at 20 °C.

Description

ARTICLE FOR THE CONTROLLED RELEASE OF A VOLATILE ORGANIC SUBSTANCE

The invention relates to an article for the controlled and substantially regular release of a volatile organic substance into the surrounding atmosphere. The volatile substance may in particular be a perfume, or an insecticide or an insect repellant.

Silicone elastomers are permeable to gases and liquids. Scent diffusion studies through a silicone wall are numerous, those through a silicone matrix are less numerous. A Japanese patent No. 82-40 558 describes the method of manufacturing a silicone elastomer matrix intended to diffuse perfume into the atmosphere. The silicone elastomer composition is mixed with the perfume and then by adding an organometallic salt, the crosslinking of the composition is triggered in a mold. The matrix obtained has a non-linear diffusion of the perfume due to an incompatibility of the polymer and of the perfume composition.

US Patent No. 4,703,070 shows the importance of incorporating a compatibilizing agent to avoid the exudation of the perfume over time. The invention describes the method of manufacturing a matrix consisting of a silicone elastomer of a compatibilizing agent and a perfume. This matrix does not, however, make it possible to obtain a linear diffusion of a constant composition over time and for temperatures ranging from 15 to 60 ° C.

There is therefore a need for an article allowing the controlled and substantially regular release of a volatile organic substance such as a perfume composition, an insecticide composition or an insect repellant composition, over a wide range of temperatures of use. The invention aims to satisfy this need.

More particularly the invention relates to an article for the controlled and substantially regular release of an active volatile organic substance into the surrounding atmosphere, which comprises a matrix of silicone elastomer (a) of the desired form in which said substance is dispersed volatile (b) and an effective amount of an agent (c) ensuring the compatibility of the volatile substance and the silicone elastomer of the matrix, characterized in that the compatibilizing agent (c) is an organic solvent having a Hildebrandt solubility parameter between 8 and 14 (cal / cm ³ ) ¹ ' ² and a vapor pressure between 0.0005 and 0.8 mm of mercury (0.06 to 105 Pa) at 20 °.

According to a particular embodiment, the volatile organic substance is a perfume or perfuming composition. According to another preferred embodiment, at least one of the following optional additional constituents is dispersed in the matrix:

an emulsifying agent (d) in an effective proportion to avoid seepage or exudation of the volatile substance (b) from the matrix (a) during storage of the device, and

- a silicone fluid (e) in an effective proportion to facilitate the release of the volatile substance (b) at temperatures ranging from 35 to 60 ° C.

As an indication, the various constituents (a) to (e) can be used in the following proportions, in% by weight relative to the total weight of the constituents (a) to (e): wide range preferred range

- silicone elastomer (a): 60-99 75-85

- volatile active substance (b)

+ solvent (c) 1 0 15-25 with the condition that the solvent (c) / substance (b) weight ratio is between 1/99 and 99/1

- emulsifying agent (d): 0-3 0.5-2

- silicone fluid 0-15 0-10

The silicone elastomer (a) can be chosen from the various types of silicone elastomer known in the art. A preferred type is that of silicone elastomers obtained from silicone elastomer compositions which crosslink at room temperature (so-called "RTV" compositions) for example under the effect of ambient humidity. These RTV silicone elastomer compositions are well known and commercially available from many suppliers. They are typically sold in two parts, namely a silicone elastomer base and a crosslinking agent which is mixed at the time of use, for example in a mold. Elastomeric compositions which crosslink under the effect of heating or radiation would also be suitable, as are crosslinking compositions in two, or even three, reactive parts.

A commercial silicone elastomer composition which has been found to be suitable is constituted by the base 3481 and the crosslinking agent DC Silastic 81 sold by the company DOW CORNING CORPORATION. The volatile active substance (b) can be a fragrance substance, an insecticide or an insect repellant, among others. Preferably, the volatile active substance is a perfuming substance.

The fragrance substance can be chosen from a large number of odorous compounds. Let us cite, by way of nonlimiting example, the substances belonging to the following families:

- aromatic, terpene and / or sesquiterpene hydrocarbons, in particular essential oils containing these molecules and more particularly essential oils of citrus fruits (lemon, orange, grapefruit, bergamot), nutmeg, etc.

- aromatic alcohols and more particularly benzyl alcohol, phenylethyl alcohol, and phenyl propyl alcohol.

- primary, secondary or tertiary, saturated or unsaturated, cyclic or acyclic non-aromatic alcohols and more particularly linalol, citronnellol, geraniol, nerol, dihydromyrcenol, terpineol, fatty alicyclic alcohols whose chain contains from 4 to 10 carbon atoms.

- aldehydes and more particularly alicyclic saturated and unsaturated fatty aldehydes whose carbon chain contains from 4 to 12 carbon atoms, aromatic aldehydes such as cinnamic, alpha-amyl-cinnamic and alpha hexyl-cinnamic aldehydes, the lilial, and phenolic aromatic aldehydes such as vanillin and ethyl-vanillin.

- phenols and more particularly aromatic phenols such as Peugenol, isoeugenol and their methyl ethers.

- esters of carboxylic acids, in particular the acetic esters of benzyl alcohol, geraniol, citronellol, nerol, terpineol, borneol, and linalool.

- esters of aromatic acids such as benzoates and salicylates as well as cinnamates esterified with alcohols of the aliphatic series having a chain of 1 to 6 carbon atoms. - aromatic phenol acids mainly in their lactonic / aromatic form such as coumarin and dihydrocoumarin.

- carboxylic alcohol acids in their lactonic form and more particularly gamma octa-, gamma undéca-, gamma dodéca-Iactones, delta déca-, delta undéca-, delta dodéca-Iactones in their saturated or unsaturated form.

- macrocyclic compounds whose carbon chain contains from 12 to 16 carbon atoms. - aromatic and / or non-aromatic ethers and acetals in their acyclic or cyclic form and more particularly the acetals of aldehydes with a carbon chain of 4 to 10 carbon atoms as well as substituted, unsubstituted or substituted pyranic cyclic ethers. - heterocyclic compounds containing a nitrogen atom and more particularly indole derivatives, as well as heterocyclic compounds containing 2 nitrogen atoms and more particularly those of the pyrazine series.

- ketones in particular aromatic ketones such as 4- (p-hydroxyphenyl) -2-butanone and non-aromatic saturated or unsaturated, cyclic or non-cyclic ketones and more particularly those of the pyrazine series.

- aromatic or non-aromatic sulfides, disulfides and mercaptans.

The fragrance substance may consist of a single odorous compound or of a mixture of such compounds. Citrus, floral and fruity fragrances have proven particularly suitable.

The solvent (c) is the essential constituent of the article of the invention. The solvent to be used must have a vapor pressure between 0.0005 and 0.8 mm Hg (0.06 and 105 Pa) at 20 ° C, preferably between 0.001 and 0.6 mm Hg (0.13 and 79 Pa) at 20 ° C.

Below 0.0005 mm Hg the solvent is insufficiently volatile and tends to accumulate on the external surface of the matrix, forming a greasy and unpleasant film. Above 0.8 mm Hg, the solvent is too volatile and the resulting article releases the active substance (b) too quickly. The solvent (c) must also have a Hildebrandt solubility parameter δ of between 8 and 14 (cal / cm ³ ) ¹⁷² , preferably between 10 and 12 (cal / cm ³ ) ^1/2 , in order to ensure satisfactory compatibility between the silicone matrix and the active substance (b). Below a value of 8 (cal / cm ³ ) ¹ ' ² and above a value of 14 (cal / cm ³ ) ¹ ' ² , a suitable compatibility is not obtained. A few examples of solvents which satisfy the above criteria are given by way of illustration and without implied limitation: δ, fcalfcπfr Vapor pressure, mm of Hg

- monomethyl ether of dipropylene glycol (1) 10.35 0.0451 - etherethyliquedediethyl glycol (2) 10.95 0.0693

- 3-methy! -3-methoxy-butanol (3) 9.33 0.5

- methyl ether of diethylene glycol 11.40 0.1086

- methyl ether of triethylene glycol 10.96 0.0037 - n-butyl ether of diethylene glycol 10.30 0.0120

- hexethyl ether of diethylene glycol. 9.91 0.0018

(1) available under the name Dowanol DPM from the company DOW CHEMICAL CORPORATION (2) available under the name Emkanol EMK from the company ICI (3) below, abbreviated as MMB

The sum of the solvent (c) and the active substance (b) must represent 1 to 40% of the sum of the ingredients (a) to (e), preferably 15 to 25%. The solvent / volatile active substance weight ratio is not very critical and can vary from 1/99 to 99/1. Preferably, this ratio is from 3/7 to 2/8, in particular approximately 1/3.

The use of a silicone fluid (d) is recommended for articles which it is desired that they can be used at relatively high temperatures, namely 35 to 60 ° C., since this constituent usually exhibits moderate volatility at temperatures. normal ambient (20 ° C). The addition of this optional component makes it possible to obtain a substantially linear release even when the ambient temperature is high (35-60 ° C.).

As silicone fluid (d), it is possible in particular to use dimethicones, cyclomethicones or dimethiconol. The choice of a particular silicone fluid must be made according to the application and the temperature of use of the article. The proportion of the fluid (d) can vary from 0 to 15% by weight. The fluids sold by the Dow Corning Corporation under the names DC 345 (cyclomethicone), DC 1401 or DC 200 have been found to be suitable.

The optional emulsifying agent (e) is useful for avoiding the problems of oozing or exudation of the active substance (b) during storage of the article. As an emulsifying agent, surfactants of all types can be used such as Tween® 20 (polysorbate 20), polyethoxylated hydrogenated castor oil (PE6-40), polysorbate 40, polysorbate 80 etc. It suffices that the agent is capable of maintaining the various raw materials used in the preparation of the article of the invention in the emulsion state until the silicone elastomer is cross-linked.

The article of the invention can be produced in a simple manner by mixing a base of silicone elastomer, the volatile active substance, the solvent and, optionally, the silicone fluid and the emulsifying agent using '' an energy agitation device. The crosslinking agent is then added with stirring and the emulsion obtained is placed under a partial vacuum ensuring the boiling. The degassed emulsion is then injected under pressure into a mold in which the silicone elastomer base will cross-link cold under the action of the cross-linking agent. It then remains only to unmold the article and to package it in a sealed package. The article of the invention can be molded into any desired shape, for example in the form of a ball, a cube, a cylinder, a polygonal structure, etc. The article of the invention , in the preferred embodiment in which the active volatile substance is a perfuming substance, can be used for perfuming a place, as a deodorant, for example for WC. or cars, as a means of scenting laundry in a dryer, etc.

The following nonlimiting examples are given for the purpose of illustrating the invention. The general preparation method described above was used in each of the examples. Example 1

An article according to the invention for use in a dryer was prepared from the following formulation: constituents% by weight

Silicone elastomer base DC 3481 72.5

Cross-linking agent DC Silastic 81 7.5 fragrance * 11

Dowanol DPM 4

DC 345 silicone fluid 4

TWEEN 20 (emulsifier) 1

* In this example and the following, Alex was sold as perfume marketed by Etablissements V. MANE Fils under catalog number M. 52548.

The article obtained, in the form of a ball with a diameter of 35 mm, was tested in a dryer with 4 kg of damp cloth at 55 ° C and for 70 min. The loss of volatile compounds (perfume + solvent) on each drying is given by the difference in mass of the article between two dryings. Figure 1 gives the% of volatile compounds remaining in the article as a function of the number of dryings. We can clearly see that the diffusion is linear.

Example 2

Test protocol:

A 4 kg load of laundry was washed in a washing machine, spinning and using unscented detergent. The laundry was then placed in a dryer with a silicone ball with a diameter of 35 mm and a weight of approximately 30 g, having the following formulation:

Constituents% by weight Silicone elastomer base DC 3481 72.50 Crosslinking agent DC Silastic 81 7.50 Perfume 11.25 Dowanol DOM 3.75 Silicone fluid DC 345 4.00 Tween 20 (emulsifier) 1.00

A similar test is carried out in parallel with a commercial product consisting of a piece of fabric impregnated with the same perfume, which is a product ("drier-sheet") commonly used on the American market. Drying cycle: 50 ° C for 70 minutes.

The linen is then evaluated by a jury of 15 people by comparing the difference in power and the pleasantness of the perfume, after drying (To), then 24 hours later (T ₂₄ ).

This test is done with balls having undergone 2, 10 and 18 drying cycles in comparison with, each time, a new "dryer-sheet". Results Question: What is the laundry before the more powerful scent?

Question: What is the laundry before the most pleasant scent?

We can see that the jury, for both the power and the pleasantness of the fragrance, mostly selects the laundry dried with 1 ball of silicone even after 24 hours. Example 3 This example highlights the importance of the solvent (c). The articles were prepared from formulations 2 to 6 similar to formulation 1 of Example 1, except that the relative proportions of solvent and perfume were varied while keeping the sum solvent + perfume equal to 15% by weight.

The table below summarizes the compositions of formulations 2 to 6.

Formulation DC3481 Silastic 81 Perfume Dowanol DPM DC 345 Twee

2 72.5 7.5 15 0 4 1

3 72.5 7.5 11.25 3.75 4 1

4 72.5 7.5 9 6 4 1

5 72.5 7.5 6 9 4 1

6 72.5 7.5 0 15 4 1

The ball-shaped artides with a diameter of 35 mm were tested in a dryer with 4 kg of damp cloth at 60 ° C and for 70 min.

FIG. 2 shows the% of volatile compounds (perfume + solvent) remaining in the artids as a function of the number of dryings. It can be seen that the release of volatile compounds is all the more rapid and extensive the more solvent there is. Example 4

In this example, five different solvents were tested, three in accordance with the invention and two outside the scope of the invention, to prepare five formulations 7 to 11 having the composition, in% by weight, indicated in the table below. .

The two solvents which did not meet the criteria of the present invention were:

- propylene glycol methyl ether (marketed under the name DOWANOL PM by the company DOW CHEMICAL CORPORATION), having a Hildebrandt solubility parameter of 11.1 (cal / cm ³ ) ^1/2 and a vapor pressure of 8 74 mm Hg at 20 ° C

- a cyclomethicone (sold under the name DC 344 by the company DOW CORNING) having a Hildebrandt solubility parameter of 5.98 (cal / cm ³ ) ¹ ' ² and a vapor pressure of 1.1649 mm of Hg at 20 ° vs. Solvent

void DC3481 Silastic 81 Partum MMB Emkanol Dowanol Dowanol DC344 * EMK DPM PM **

7 72.5 7.5 15 5 - - -

8 72.5 7.5 15 - 5 - -

9 72.5 7.5 15 - - 5 -

10 72.5 7.5 15 - - - 5

11 72.5 7.5 15 - - - 5

** excluding invention; given for comparison.

From these formulations, ball-shaped articles with a diameter of 35 mm were prepared and tested in a tumble dryer as in the previous examples.

FIG. 3 shows the% of volatile compounds (perfume + solvent) remaining in the articles as a function of the number of dryings. We see that the three solvents according to the invention have comparable behaviors, much superior to the two comparison solvents, not in accordance with the invention.

It goes without saying that the embodiments described are only examples and that they could be modified, in particular by substitution of technical equivalents, without departing from the scope of the invention.

Claims

1. An article for the controlled and substantially regular release of a volatile active organic substance into the surrounding atmosphere, which comprises a silicone elastomer matrix (a) of the desired form in which said volatile substance (b) is dispersed and an effective amount of an agent (c) ensuring the compatibility of the volatile substance and of the silicone elastomer of the matrix, characterized in that the compatibilizing agent (c) is an organic solvent having a Hildebrandt solubility parameter included between 8 and 14 (cal / cm ³ ) ^1/2 and a vapor pressure between 0.0005 and 0.8 mm of mercury (0.06 to 105 Pa) at 20 ° C.

2. Article according to claim 1, characterized in that the organic solvent has a vapor pressure between 0.001 and 0.6 mm Hg (0.13 and 79 Pa) at 20 ° C.

3. Article according to claim 1, characterized in that the volatile active substance is a perfume, a perfuming composition, an insecticide or an insect repellant.

4. Article according to claim 1, characterized in that the volatile active substance is a perfume or perfuming composition.

5. Article according to any one of claims 1 to 4, characterized in that at least one of the following optional additional constituents is dispersed in the matrix:

6. Article according to any one of claims 1 to 5, characterized in that the constituents (a) to (e) are used in the following proportions, in% by weight relative to the total weight of the constituents (a) to ( e): 60 to 99% of silicone elastomer (a) 1 to 40% in total of volatile active substance (b) and of solvent (c) 0 to 5% of emulsifying agent (d), and 0 to 15 % of silicone fluid (e); with the condition that the solvent (c) / substance (b) weight ratio is between 1/99 and 99/1.

7. Article according to claim 6, characterized in that the solvent (c) / substance (b) weight ratio is between 3/7 and 2/8.

8. Article according to claim 7, characterized in that the solvent by weight ratio c) / substance (b) is approximately 1/3.

9. Article according to any one of claims 1 to 8, characterized in that the solvent (c) has a Hildebrandt solubility parameter between 10 and 12 (cal / cm ³ ) ¹ ' ² .

10. Article according to claim 6, characterized in that the silicone elastomer (a) represents 75 to 85%, and the total of the volatile active substance (b) and of the solvent (c) represents 15 to 25%.

11. Article according to any one of claims 1 to 10, characterized in that the solvent is monomethyl ether of dipropylene glycol