WO2006063483A1

WO2006063483A1 - Olfactive delivery composition

Info

Publication number: WO2006063483A1
Application number: PCT/CH2005/000752
Authority: WO
Inventors: Sandrine Dumas Krikorian; Cédric GEFFROY; Markus Schudel
Original assignee: Givaudan Sa; Dow Corning Corporation
Priority date: 2004-12-16
Filing date: 2005-12-15
Publication date: 2006-06-22
Also published as: EP1828370A1; CN101098955A; KR20070089696A; JP2008524343A

Abstract

Particles of silicone in which fragrance or fragrance precursor is encapsulated, the silicone comprising at least one waxy alkylpolysiloxane, from 1 to 90% by weight of fragrance or fragrance precursor in the particles comprising at least 70% of fragrance ingredients of at least one of class 1 and 2 (as defined in the description), and having an odour value (as defined in the description) of at least 50000. Especially good results are obtained by the combination of this fragrance and a waxy cyclopolysiloxane. The fragranced particles of the invention deliver more fragrance on fabric and longer over time than silicone-fragrance particles known to the art.

Description

OLFACTIVE DELIVERY COMPOSITION

The present invention relates to an improved delivery composition for olfactive compounds and precursors thereof, in particular perfume ingredients, malodour counteracting agents, precursors and mixtures thereof.

A large part of the olfactive material (fragrance, fragrance precursor and odour masking material) initially added to detergent products, soaps and conditioners is lost by evaporation, chemical degradation upon storage and emulsification and further elimination in the wash and rinse water. Accordingly, substantial work has been devoted to the general problem of fragrancing various substrates, such as garments, during washing and thereafter during the conditioning procedure, in order to enhance fragrance deposition on the substrates and to provide a sustained release of fragrance during drying and storage.

A classical method for enhancing fragrance deposition is admixing the fragrance with surfactant, especially cationic surfactant, contained in conditioner compositions. Another method is to add fragrance in the form of silicone-fragrance particles, which provide fragrance to a substrate over a prolonged period of time. By silicone-fragrance particles is meant particles of silicone material which contain fragrance. The silicone-fragrance mixture should have a melting point or a glass transition above 2O⁰C. The silicone used is typically an alkyl graft linear polysiloxane.

International Application WO 2004/084844 discloses the use of certain waxy cyclopolysiloxanes in conjunction with perfumes. These cyclopolysiloxanes tend to be more miscible with the perfume compounds and provide a longer lasting effect. .

It has now been found that it is possible to prepare silicone-fragrance particles that deliver fragrance more efficiently than other silicone-fragrance particles known to the art, by means of a particular selection of fragrance, preferably in conjunction with a preferred silicone. The invention therefore provides particles of silicone in which fragrance or fragrance precursor is encapsulated, the silicone comprising at least one waxy alkylpolysiloxane, from 1 to 90% by weight of fragrance or fragrance precursor in the particles comprising at least 70% (more preferably at least 80%, most preferably at least 90%) of fragrance ingredients of at least one of class 1 and 2 (as hereinunder defined), and having an odour value (as hereinunder defined) of at least 50000.

The particles of this invention deliver more perfume on fabric and longer over time than known silicone-fragrance particles. The invention therefore also provides a method of imparting a fragrance to a substrate, comprising the addition to the substrate of fragrance in the form of silicone-fragrance particles as hereinabove defined.

By "waxy" is meant an alkylpolysiloxane that is a low melting point material. For the purposes of this invention, such alkylpolysiloxanes have a melting point of from 10°-200°C and have at least 20% of the silicon atoms substituted by at least one alkyl substituent having from 12 to 100 carbon atoms. Most of these materials have the characteristics generally thought of as "waxy", that is, they are soft solids or viscous fluids.

Although any waxy alkylpolysiloxane suitable for making such particles may be used in the working of this invention, it has been found that the best results are obtained by using a cyclopolysiloxane. The best cyclopolysiloxanes for use in this invention are the waxy cyclopolysiloxanes described in the abovementioned International Application WO 2004/084844. The invention will be described with particular reference to these materials (hereinafter simply referred to as "cyclopolysiloxanes"), but it should be borne in mind that the scope of the invention is wider than that, and that the skilled person can use waxy alkylpolysiloxanes outside this preferred category of materials.

A particularly preferred class of cyclopolysiloxanes is that of waxy materials having hydrocarbon substituents of at least 12 carbon atoms. Preferably the cyclopolysiloxanes comprise methyl alkyl siloxane units ((CH₃)(R')(Si0_2/2)), in which R' is a long chain alkyl group having at least 12, preferably from 16 -100 carbon atoms. R' can optionally be substituted by polar substituents such as amino, amido, alcohol, alkoxy or ester groups. All the siloxane units may be such methyl alkyl siloxane units, or the waxy cyclopolysiloxane may additionally contain dimethyl siloxane units of units of the formula ((CH₃)(R")(Siθ2/₂), where R" is an alkyl group having from 1-11 carbon atoms, for example, an ethyl group, a cycloalkyl group such as 2-cyclohexylethyl, a haloalkyl group, or an aromatic group. The methyl group of the abovementioned siloxane units may be replaced by ethyl or another lower alkyl group, if desired. 2

3

Preferably at least 20%, more preferably at least 50%, of the silicon atoms in the cyclopolysiloxane have an alkyl substituent having from 16-100 carbon atoms, most preferably from 20-45 carbon atoms. The cyclopolysiloxane is preferably a cyclotetrasiloxane or a cyclopentasiloxane or a mixture thereof. A further preferred type of waxy cyclopolysiloxanes contains aromatic groups, for example aryl groups attached directly to Si, such as phenyl, or aralkyl groups comprising phenyl or substituted phenyl groups attached to silicone through an alkylene linkage, in addition to long chain alkyl groups. Particularly preferred are waxy cyclopolysiloxanes containing aralkyl groups, that is, silicon-bonded substituents of the formula X-Ph, wherein X denotes a divalent aliphatic organic group bonded to silicon through a carbon atom and Ph denotes an optionally- substituted aromatic group. Examples of such suitable groups include 2-phenylproρyl, benzyl, 2-phenylethyl, and 2-(fert-butylphenyl) ethyl. Such aralkyl groups may be present in 10-80%, preferably from 20-50% of the siloxane units of the waxy cyclopolysiloxane, usually as methyl aralkyl siloxane units.

The melting point of the waxy cyclopolysiloxane is preferably from 10°-200°C, more preferably from 30° to 100⁰C, more preferably from 30° to 85°C.

The waxy cyclopolysiloxane can be mixed with a liquid silicone, for example, a polydiorganosiloxane, a branched liquid polysiloxane, a silicone ether copolymer or an aminopolysiloxane. Particularly preferred liquid polysiloxanes are those containing aryl groups, such as phenyl, and aralkyl groups, such as benzyl, 2-phenylethyl and 2- phenylpropyl, as well as alkyl groups such as methyl. The liquid polydiorganosiloxane may be linear or cyclic, cyclic siloxanes such as tetra(2-phenylpropyl)tetramethylcyclotetra- siloxane being preferred. The liquid polysiloxane may comprise functional groups, for example, hydroxyl groups such as terminal silanol groups in a linear polydiorganosiloxane such as polydimethylsiloxane, alkoxy groups such as methoxy, ethoxy or propoxy bonded to silicon, or amino, amido, alcohol or alkoxy groups substituted in an organic group bonded to silicon.

The waxy hydrophobic mixture of the waxy cyclopolysiloxane and the liquid silicone is preferably a solid, preferably having a melting point in the range 10°-200°C. However, it may also be a viscous liquid. The liquid silicone may be used at a level of up to 100% or even higher, based on the weight of wax, for example up to 200% or 300%, particularly if a blend of wax and liquid silicone is solid at 10°C, although the liquid silicone if used is preferably present at a rate of from 1-60%, preferably from 1-30%, based on the weight of wax. An organic liquid, such as liquid paraffin or a naphthenic oil, can be used alternatively or additionally if it is compatible with the blend of fragrance composition and waxy cyclopolysiloxane.

The blend of fragrance composition and waxy cyclopolysiloxane can incorporate a further wax, for example, a linear polysiloxane wax or an organic that does not contain silicon, although the waxy cyclopolysiloxane preferably forms a at least 0% by weight of the wax component of the blend. Suitable linear polysiloxane waxes generally contain methyl alkyl siloxanes units ((CH₃)(R')(SiO_2/2)) as hereinabove described and can contain other substituents such as aralkyl, aryl or cycloalkyl groups as hereinabove described for the waxy cyclopolysiloxane.

The selection of the fragrance is a particularly important part of this invention. The combination of the particular fragrance and the preferred cyclopolysiloxanes leads to products with especially desirable properties.

It has been found that fragrance ingredients that are compatible and stable with this cyclopolysiloxane wax perform better on fabric than incompatible and unstable ingredients. This is because of the tendency of stable fragrances to remain in the cyclopolysiloxane phase and therefore for there to be more fragrance available to deposit on the fabric.

By "compatible" is meant that the fragrance ingredients are completely soluble in the pure alkyl polysiloxane in the proportions of from 10:90 (10% fragrance to 90% silicone) to 90:10 above the melting point of the silicone

By "stable" is meant that the particles with fragrance dissolved therein are stable in a surfactant environment, such as a fabric softener, the fragrance ingredients preferring to remain in the silicone particles rather than going into the aqueous phase. Stability is measured by testing fragrance-silicone particles after preparation and storage at 40°C for one week. For this purpose, 20% of a 50/50 (weight) fragrance-silicone blend is dispersed in water containing 20% of cationic surfactant, the water being at a temperature higher than the silicone melting point or its Tg. The fragranced silicone particles thus formed have a particle size of from l-100μm. The mixture is allowed to cool and is stored at 4O⁰C for a week. During this time, unstable ingredients migrate from the silicone phase to the water phase and the stability can be determined by analysis of the water phase. The water phase is diluted by adding 4 volumes of water to the one volume of dispersion. In the case of phase separation, the lower phase is separated and filtrated with a membrane filter (Porex™) of 0.45um. In the contrary case, when there is no phase separation, the diluted formulation is filtered firstly with a membrane filter (Porex™) of 5μm and secondly with a 0.45μm one. This filtration method ensures that there are no remaining silicone-fragrance particles in the fragranced water to be further analyzed. The fragranced water phase, cleaned of any silicone residues, is mixed with a diatomaceous earth (such as Celite™ 545) prior to extraction by a solvent such as pentane and analysis by gas chromatography with a Flame Ionisation Detector (FID). The measurement of the quantity of perfume ingredients present in the water phase provides an indication of their migration from the silicone to the water and therefore on which perfume ingredients may be considered stable: Fragrance ingredients having a migration rate of less than 46% are considered stable.

This test allows the classification of fragrance materials into three classes, namely:

Class 1: less than 25% by weight of migration of perfume ingredient to water after 1 week of storage at 40°C in the aforementioned conditions; Class 2: between 25% and 46% migration; Class 3: more than 46% migration.

In addition, the materials of the classes can be more precisely defined by reference to certain structure-derived parameters calculated by commercially-available computer software. Initially the molecular structures of the perfume ingredients are extracted from a molecular database containing structural data (SD) file formats (see Cerius² 4.6, Accelrys, San Diego, CA, USA, 2001). This SD-file is used as the input of the two-dimensional structure of the compound into the Cerius² 4.6 molecular spreadsheet two or three dimensional (normally both SD-files) and the output file in 3 dimensions). Conversion into low-energy 3D structures is achieved by molecular mechanics of Open Force Field (OFF, see Cerius² 4.6, Accelrys, San Diego, CA, USA, 2001.)- This 3D structure has further been optimized using AMI Hamiltonian of MOPAC6 (see again Cerius² 4.6, Accelrys, San Diego, CA, USA, 2001). The computer program 'MOPAC6' is a public domain program developed and maintained by J. J. P. Stewart and distributed by the Quantum Chemistry Program Exchange, Bloomington, Indiana, USA).

All the available descriptors of Cerius² 4.6 QSAR Descriptor^1" (the Cerius2 4.6 QSAR Descriptor* ™ is a product of Accelrys). are then computed (Cerius² 4.6, Accelrys, San Diego, CA, USA, 2001). The parameters that are calculated are the following:

Shadow-YZfrac

Shadow indices in general help to characterize the shape of the molecules. The descriptors are calculated by projecting the molecular surface on three mutually perpendicular planes, XY, YZ, and XZ (Rohrbaugh and Jure, Analytica Chimica Acta 199, 99-109, 1987)).

Shadow-YZfrac is the ratio of the area corresponding to the shadow of a molecule projected onto the plane YZ divided by the area of rectangle box enclosing this shadow.

These descriptors depend not only on conformation but also on the orientation of the molecule. To calculate them, the molecules are first rotated to align the principal moments of inertia with the X, Y, and Z axes. These descriptors may further account for the interaction of the fragrance molecule with the surrounding matrix.

Dipole-mag

The dipole moment descriptor 'Dipole-mag' is a 3D electronic descriptor that indicates the strength and orientation behavior of a molecule in an electrostatic field by using charge equilibration (Cerius² 4.6 Simulation Tools, Cerius² 4.6, Accelrys, San Diego, CA, USA, 2001.). Both the magnitude and the components (X, Y, Z) of the dipole moment are calculated. It is estimated by utilizing partial atomic charges and atomic coordinates (Cerius 4.6, Accelrys, San Diego, CA, USA, 2001.) Fh2O

Fh2O is the calculated desolvation free energy of a perfume ingredient for water. Fh2O is the aqueous desolvation free energy derived from a hydration shell model developed by Hopfmger, where Fh20 are in kcal mol^"1 (Hopfmger, A. J., Conformational Properties of Macromolecules, Academic Press: New York (1973). Hopfmger, A. J. et al. Safe Handling of Chemical Carcinogens, Mutagens, Teratogens and Highly Toxic Substances, D. B. Walters, Ed., Ann Arbor Press: Ann Arbor, p. 385 (1980). Pearlman, R. S. Physical Chemistry Properties of Drugs, Eds. S. H. Yalkowsky, A. A. Sinkula, Y. C. Valvani, Dekker: New York (1980)). Fh2O are physiochemical properties having proven useful as molecular descriptors in structure-activity analyses, are based solely on the connectivity of the atoms in a molecule and computations are not conformationally dependent.

RadOfGyration The radius of gyration is calculated using the following equation:

RadOfGyration =

where N is the number of atoms and x, y, z are the atomic coordinates relative to the center of mass.

LUMOJdOPAC

LUMO (LUMO = lowest unoccupied molecular orbital) is the calculated lowest energy level in the molecule that contains no electrons calculated by the MOPAC6' (M0PAC6' is a public domain program developed and maintained by J. J. P. Stewart and distributed by the Quantum Chemistry Program Exchange, Bloomington,. Indiana, USA).). When a molecule acts as a Lewis acid (an electron-pair acceptor) in bond formation, incoming electron pairs are received in its LUMO. Molecules with low-lying LUMOs are more able to accept electrons than those with high LUMOs. The LUMO descriptor can be also taken as a measure of the electrophilicity of a molecule.

Thus, in addition to the migration figures hereinabove defined, the materials of the classes should preferably have the following characteristics:

A fragrance ingredient is CLASS 1 if the following parameter sets are met: (i) Shadow- YZfrac > 0.643 AND Dipole-mag < 1.877 AND Fh20 > -4.134 OR

(ii) Shadow-YZfrac > 0.643 AND Dipole-mag < 1.877 AND Fh20 < -8.067 AND RadOfGyration > 3.101.

A fragrance ingredient is CLASS 2 if the following parameter sets are met: (i) Shadow- YZfraO 0.643 AND Dipole-mag> 1.877 AND

Shadow- YZfrac≤ 0.73_.7 OR (ii) Shadow- YZfrac>0.643 AND Dipole-mag < 1.877 AND Fh2O < -4.134 AND

Fh2O > -8.067 OR (iii) Shadow-YZfrac<0.643 AND LUMO_MOPAC > -0.788.

A fragrance ingredient is CLASS 3 if there is more than 46% migration of perfume ingredient to water.

The fragrance-silicone particles according to this invention can be made by any convenient means. For example, the particles can be prepared and then added to a product such as a fabric softener at a temperature higher than their melting point. A further method (and the preferred one for the purposes of this invention) is to disperse fragrance-silicone particles in water, both water and particles being at a temperature of more than 70⁰C, and to stabilise them using surfactant. The resulting emulsion has the form of a cream, and it can be easily added in a cold process to a product such as a fabric softener.

Emulsions of perfume-silicone particles according to this invention were incorporated in fabric softener and evaluated on wet and dry fabric after 24 hours and 5 days, with freshly- prepared samples and after storage of 1 month at 4O⁰C. Olfactory evaluation comparisons were made between perfume ingredients incorporated directly in fabric softener at 0.1% and same perfume ingredient amount incorporated firstly in silicone particles emulsion and then in fabric softener. Olfactory evaluation results identified perfume ingredients with an odour value (OV)>50000 and from Class 1 and 2 (migration less than 46% in water) as the best performing ingredients on dry fabric over time. OV= HS/TH, where HS is Head space and TH threshold, both being measured in nanograms per litre. The term OV is described in the literature. ( Ref: Neuner-Jehle, N. and F. Etzweiler."The measuring of odors", in Perfumes: Art, Science and Technology, P.M. Mϋller and D Lamparsky, eds Chapman& Hall, London, pp 153-212, 1994)

Surfactant may be used to disperse and stabilize physically these perfume-silicone particles in an aqueous phase. Suitable surfactants may be selected from anionic, cationic, zwitterionic and non-ionic surfactants, cationic surfactants being preferred. The use level is from 0.1 - 40%, preferably from 5 - 20%, by weight of the total weight of surfactant+ fragrance+siloxanes +water. Fragrance loading in the formulation may vary from 1 to 50%, more preferably from 1.5 to 30%. The weight range of siloxane:fragrance is from 1:1 to 8:1 and the weight ratio of total surfactant to siloxane is from 3:1 to 0:1. The preferred weight ratios of fragrance:siloxane:surfactant are 1/4/2 and 2/4/0 to 2/4/4.

The fragrance encapsulated in silicone is a composition of at least 1 ingredient of class 1 or class 2. The weight percentage of encapsulated fragrance of the total fragrance used in a finished product such as a fabric softener may vary from 0.001 to 100%, preferably from 0.005 to 50%, more preferably from 0.01 to 35%.

The combination of the cyclopolysiloxane and the fragrances of class 1 and class 2 gives a composition that retains fragrance well and releases it on fabric for a period of up to 5 days in a controlled manner (i.e. the early release rate is lower than that observed with a non- encapsulated perfume and the exponentially declining release rate observed with free fragrance is slowed down). This leads to the desired longevity. If fabrics are treated with a fabric conditioner comprising the particles of this invention and then stored for 1 month at 40°C, the intensity of the fragrance is at least 0.5 higher than if the fragrance had been free fragrance (the intensity scale and its measurement are further described in the examples).

A further advantage of the invention is that the encapsulated fragrance ingredients are protected from possible external chemical degradation, a common problem of perfumes that are added directly to fabric softeners. The compositions according to the invention permit a significant enhancement of deposition on to a substrate, such as a fabric, a solid surface, or hair and skin. A superior olfactive performance is obtained thereby. Superior sustained release is also obtained.

The particles are useful in any household or personal care product in which it is desirable to deposit fragrance on the substrate in an efficient and enduring manner. The invention therefore also provides a household or personal care product, comprising silicone-fragrance particles as hereinabove defined. Household and personal -care products include laundry and household detergents and cleaning agents, fabric conditioners, polishes, soaps, cosmetics, skin creams, and so on.

The invention is further described with reference to the following non-limiting examples.

Example 1

Comparative olfactory evaluations were made of a fabric conditioner formulation, with a fragrance (with ingredients from classes 1 and 2) in alkyl graft linear silicone particles, in alkyl graft cyclic polysiloxane and as free fragrance.

Wash cycles with a fabric load of 1.2 kg of 250 g terry towelling with 5Og of unperfumed powder detergent, followed by a rinse cycle with 35g of perfumed fabric softener were performed for 3 samples containing:

-0.8% perfume A

-0.8% perfume A contained in alkyl graft linear Silicone particles (AMS C-30 from Dow Corning)

-0.8% perfume A contained in alkyl graft cyclopolysiloxane particles, (from Dow Corning)

The olfactive performance of these terry towels was assessed by a panel of 10 experts on wet fabrics and on dry fabrics after 24 hours and 5 days. Comparisons were made using an intensity scale from 0 to 5 (0 means barely detectable, 1: weak, 2: moderate, 3: strong, 4: very strong, 5: strongest imaginable) and a quality scale from 0 to 5 (0 means very poor, 1 : poor, 2: fair, 3: good, 4: very good, 5: excellent) The results are shown in the table below:

1. The material used was AMS C-30 ex Dow Corning, a cyclopolysiloxane with an alkyl chain of 30 carbon atoms.

These results show a significant improvement of performance of cyclopolysiloxane wax particles versus alkyl-grafted linear polysiloxane particles and free perfume.

Example 2

Fragrance particles were prepared, using the following fragrance ingredients:

These ingredients each were used in the preparation of cyclopolysiloxane paticles according to the following formula. Fragrance ingredients were mixed in the fragrance/silicone ratio of 1/4 and then emulsified with cationic surfactant.

Ingredients A and B were premixed and heated at 8O⁰C. Ingredients F, G, H, I were premixed to form a gel and then added to C, D, E at 80⁰C.

Mixture A/B was added to Mixture C-I and mixed in a homogeniser at 80⁰C for 5 min, the transferred to a conventional stirrer and completed at 1200rpm up to room temperature. The emulsion of fragrance-silicone particles obtained was then incorporated at 2.4% in a fabric softener formulation. Such particles can be used to deliver all of the fragrance needed to a fabric, without any need for free fragrance.

The particles thus prepared are tested in the following examples.

Example 3

Olfactory evaluations were carried out on benzyl cinnamate, a Class 3 fragrance, using 100% encapsulated (as prepared in Example 3) versus 100% free benzyl cinnamate, at 0.1% in fabric softener on fresh samples and after 1 month storage at 4O⁰C.

Results are given in intensity difference between silicone particles samples and free fragrance samples, after 24 hours and 5 days on dry fabric. The intensity difference is the difference observed between that of the particles and that of the free fragrance, and is assessed as hereinabove described. Results:

Evaluations confirm that Benzyl Cinnamate, Class 3, is not compatible with the silicone and should not be used in this system of particles.

Example 4

Olfactory evaluations were done on Damascone delta, Class 1, 100% encapsulated versus 100% free Damascone delta at 0.1 % in fabric softener.

Results are given in intensity difference between silicone particles samples and free fragrance samples, after 24 Hours and 5 days on dry fabric.

Evaluations confirm that Damascone Delta, Class 1 and OV>50000, is compatible with silicone and enhance release over time with fresh and aged sample up 5 days minimum Example 5

Olfactory evaluations were carried out on verdyl propionate, a Class 2 fragrance, using 100% encapsulated versus 100% free verdyl propionate, at 0.1% in fabric softener on fresh samples and after 1 month storage at 40°C.

Results:

Evaluations confirm that Verdyl propionate, Class 2, compatible with the silicone and OV>50000 should be used in this system of particles.

Example 6

Olfactory evaluations were done on Ambrettolide, Class 2, 100% encapsulated versus 100% free Ambrettolide at 0.1% in fabric softener.

Evaluations confirm that Ambrettolide, Class 2 and OV<50000 is stable within the silicone but doesn't enhance significant release over time with fresh and aged sample. Ambrettolide should not be used in this system of particles because OV is < 50000.

Example 7

A Perfume Peach B, premixed with the cyclopolysiloxane wax and then emulsified in formulation 1/4/2 described in the aforementioned protocol is stored for 1 week at 4O⁰C, filtered and extracted by solvent to identify perfume ingredient migration in water. Results are indicated in the following table:

This perfume Peach B contain more than 90% of ingredients with a migration rate in water less than 46%.

Evaluations were done after incorporation in a fabric softener in the proportionof 30% encapsulated and 70% free fragrance Peach B, versus 100% free. Results are indicated in the following table:

Results show a significant improvement on dry fabric of the encapsulated samples.

Claims

Claims:

1. Particles of silicone in which fragrance or fragrance precursor is encapsulated, the silicone comprising at least one waxy alkylpolysiloxane, from 1 to 90% by weight of

. the total composition of fragrance or fragrance precursor conforming to the following requirements:

(a) containing at least 70%, more preferably at least 80%, most preferably at least 90%, of fragrance ingredients with an odour value (OV) of at least 50000, where . OV= Head Space/Threshold; and (b) belonging to class 1 or class 2, class 1 and 2 being defined as follows:

Class 1: showing a migration of fragrance ingredients from silicone to water of less than 25% by weight after 1 week of storage at 40⁰C of a 20% aqueous dispersion of a 50/50 (weight) fragrance-silicone blend, the aqueous phase containing 20% of cationic surfactant and being at a temperature higher than the silicone melting point or its Tg;

Class 2:

(1) showing a migration of fragrance ingredients to water of between 25% and 46% in the conditions specified under "Class 1".

2. Particles according to claim 1, in which the fragrance complies with the following parameter sets:

Class 1:

(i) Shadow- YZfrac > 0.643 AND Dipole-mag < 1.877 AND Fh2O > -4.134

OR

(ii) Shadow- YZfrac > 0.643 AND Dipole-mag < 1.877 AND Fh2O < -8.067 AND

RadOfGyration > 3.101;

Class 2:

(i) Shadow- YZfraO 0.643 AND Dipole-mag> 1.877 AND Shadow- YZfrac≤ 0.737

OR (ii) Shadow- YZfraOO.643 AND Dipole-mag < 1.877 AND Fh20 < -4.134 AND

Fh20 > -8.067 OR (iii) Shadow-YZfrac<0.643 AND LUMO_MOPAC > -0.788.

3. Particles according to claim 1, in which the waxy alkylsiloxane is a cyclopolysiloxane.

4. Particles according to claim 3, in which the cyclopolysiloxane has at least one hydrocarbon substituent of at least 12 carbon atoms, preferably from 16 to 100 carbon atoms, more preferably from 20 to 45 carbon atoms.

5. Particles according to claim 3, in which at least 20%, more preferably at least 50%, of the silicon atoms in the cyclopolysiloxane have an alkyl substituent having from 16-100 carbon atoms, most preferably from 20-45 carbon atoms.

6. Particles according to claim 3, in which the melting point of the waxy cyclopolysiloxane is from 10°-200°C, preferably from 30° to 100°C, more preferably from 30° to 7O⁰C.

7. A method for the enhanced deposition of fragrance on a substrate, comprising the addition to the substrate of fragrance in the form of silicone-fragrance particles according to claim.1.

8. A fragranced household or personal care product, comprising silicone-fragrance particles according to claim 1.