RU2774912C2 - Encapsulated perfume composition and its production method - Google Patents

Abstract

FIELD: cosmetology.

SUBSTANCE: group of inventions relates to a perfume composition. An encapsulated perfume composition contains at least one core-shell microcapsule suspended in a suspending medium, where the specified at least one core-shell microcapsule contains a core containing at least one perfume ingredient and a shell surrounding or at least partially surrounding the core; the shell contains thermosetting resin formed by the reaction of shell-forming materials selected from a group consisting of monomers, prepolymers and/or pre-condensation products, and the encapsulated perfume composition contains a polymer stabilizer, which is a product of the reaction of a polymer surfactant and silane containing a functional group capable of forming covalent bonds with the shell. Methods for the production of an encapsulated perfume composition are also disclosed.

EFFECT: group of inventions ensures the stability of a composition.

17 cl, 2 tbl, 6 ex

Description

Technical field

The present invention relates to an encapsulated perfume composition in the form of a dispersion of core-shell type microcapsules. The invention also relates to methods for forming an encapsulated perfume composition, its use in consumer products, as well as consumer products containing it.

State of the art

Demand for encapsulated perfumes across all categories of consumer products, including personal care products, home care products and especially laundry products, continues to grow. As a result, perfumers are required to include fragrance-containing microcapsules in even more diverse product types and in even more problematic (eg aggressive or extractive) environments.

This increase in consumer demand reflects the increasing importance of fragrance to consumers of personal care, home care and fabric care products. The aroma provides an olfactory stimulus that gives consumers an impression of freshness and cleanliness, which in turn reinforces the consumer's belief in the effectiveness of such products.

There are many points in time when the consumer interacts with the product before, during and after the cleaning or treatment. In the case of laundry products, for example, moments of interaction during washing include the feeling of freshness that the consumer gets when opening a container of fabric care agent, or when opening a washing machine or dryer after washing or drying clothes, or a feeling of freshness associated with ironing. , folding or normal handling of freshly laundered clothes or linen. If a laundry product can generate consumer enjoyment during these moments of interaction, it can help transform tedious housework into a more enjoyable experience and create moments of pleasure that foster brand loyalty and encourage repeat product purchases.

Microencapsulation technology offers the possibility of controlling the spatio-temporal release of odor during cleaning or processing, thus contributing to the aforementioned consumer benefits.

A wide variety of encapsulating media and perfume ingredients suitable for the preparation of encapsulated perfume compositions have been proposed in the art.

Encapsulating media provided in the art include synthetic resins made from polyamides, polyureas, polyurethanes, melamine-derived resins or mixtures thereof, or naturally occurring polymers such as gelatin, starches, and the like.

With regard to suitable core materials, in principle all perfume ingredients on a perfumer's palette can be included to some extent in a core-shell type microcapsule. However, it is generally believed that certain physico-chemical characteristics of a perfume ingredient, the most significant of which is clog P, affect whether it can be encapsulated and to what extent, and after encapsulation, its tendency to remain in the core without significant leakage into the course of storage.

In the experienced formulation designer, judicious selection of both shell and core materials can result in a microencapsulated perfume that is suitable for many consumer products and that is capable of changing odor release over time, at least to some degree.

However, even when using relatively stable shell chemicals in combination with a properly designed perfume core formulation, the formulation designer still faces a difficult trade-off between ensuring, on the one hand, that the microcapsules are sufficiently reliable to be stable and not leak during manufacturing and storage, and, on the other hand, sufficient degradability to release the contents of the core with the desired release profile when applied to the wet and dry stages of the cleaning or processing operation.

One means of improving long-term perfume performance is to allow core-shell microcapsules to settle and anchor on treatable substrates such as fabrics and keratin substrates. Microcapsules that are not easily washed out of the base to be treated are capable of producing a pleasant fragrance sensation for a longer period of time.

Accordingly, many attempts have been made to solve this problem and to obtain microcapsules that are deposited and remain on keratin surfaces after rinsing. These attempts have mainly used polymers as deposition aids. For example, WO 2015/041791 A1 describes microcapsules coated with a deposition aiding polymer which is a cationic polymer having a cationic charge of 0.005 meq/g to 23 meq/g, preferably 0.01 meq/g to 12 meq/g, most preferably from 0.1 meq/g to 7 meq/g at the pH of the composition in which the microcapsules are present. WO 2016/177607 A1 describes polyurea microcapsules containing a non-ionic polysaccharide covalently linked to a polyurea shell. The polysaccharide is selected from the group consisting of mannan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan and mixtures thereof, and a significant improvement in the deposition of microcapsules on treated substrates is claimed. However, while these polymers are intended to enhance the deposition and adhesion of microcapsules to various substrates, any enhancement is still limited for rinse-off products. Chemical modification of microcapsules to enhance deposition appears to have its limitations. Moreover, any chemical modification of the sheath can change its properties and have a detrimental effect on the leakage stability.

There remains a need for improved encapsulation technologies that provide leak stability and are even more efficient in application, not least because they are more effective on treated surfaces such as fabric and keratin surfaces.

Brief description of the invention

Turning to the problems of the prior art, the Applicant has found that a contributing factor explaining the observed limited deposition and retention of microcapsules on treated surfaces, especially under rinse conditions, relates to the particle size and polydispersity of the microcapsules used in prior art encapsulated perfume compositions. More specifically, core-shell microcapsules are typically prepared from oil-in-water emulsions in which dispersed oil droplets act as supports around which resin shells are deposited to form core-shell microcapsule suspensions. Such emulsions, which are stabilized with conventional polymeric stabilizers, are usually polydisperse, resulting in a microcapsule population containing a significant number of microcapsules that are either too large or too small to provide the required settling and retention of the microcapsules on the surfaces to be treated, especially under flushing conditions. .

Surprisingly, novel polymeric stabilizers and methods for forming microcapsules have been discovered that help control polydispersity in a core-shell microcapsule population. It has also been found that encapsulated perfume compositions formed using the new polymeric stabilizers adhere strongly to surfaces on which they are deposited and perform well in consumer products compared to prior art encapsulated perfume compositions.

Moreover, new polymeric stabilizers have been found to be so effective at stabilizing the oil-water interface that they contribute to providing a particularly stable platform around the perfume oil droplets, onto which not only existing shell chemicals, but also new shell chemicals, are deposited. with the formation of new encapsulated perfume compositions, which gives the formulation designer more freedom to design microcapsules with additional functionality or desired properties, for example, microcapsules that do not contain residual aldehydes, in particular formaldehyde.

Accordingly, in a first aspect of the invention, there is provided an encapsulated perfume composition comprising at least one core-shell microcapsule suspended in a suspending medium, wherein said at least one core-shell microcapsule contains a core containing at least one perfume ingredient, and shell surrounding or at least partially surrounding the core, where the shell contains a thermosetting resin formed by the reaction of shell-forming materials selected from monomers, prepolymers and/or precondensation products, and the encapsulated perfume composition contains a polymeric stabilizer, which is a reaction product of a polymeric surface -active substance and a silane containing a functional group capable of forming covalent bonds with the shell.

In the second aspect of the invention, a method for obtaining the above encapsulated perfume composition is provided, comprising the steps:

i) forming an oil-in-water emulsion comprising at least one drop of oil dispersed in an external aqueous phase containing a perfume ingredient and a polymer stabilizer, and

ii) reacting the sheathing materials present in the oil-in-water emulsion and forming, at the oil-water interface, a sheath of thermosetting resin surrounding at least partially said at least one drop of oil.

In a third aspect of the invention, there is provided a consumer product, in particular a consumer product suitable for use in flush applications, comprising the present encapsulated perfume composition.

In a fourth aspect of the invention, a polymeric stabilizer is provided which is a reaction product of a polymeric surfactant and a silane that contains a functional group that is capable of forming a covalent bond with the shell of a core-shell microcapsule.

A fifth aspect of the invention provides for the use of a polymeric stabilizer in the preparation of an encapsulated perfume composition.

In a sixth aspect of the invention, the use of a polymeric stabilizer in the preparation of an encapsulated perfume composition is provided to control the polydispersity of the core-shell microcapsules so that the polydispersity of the core-shell microcapsules is less than 1.5, more preferably less than 1.3, even more preferably less than 1, 2.

In specific embodiments of any aspect of the invention, the polymeric stabilizer is a copolymer formed by the reaction of an aminosilane and a hydrolyzed maleic anhydride copolymer.

In specific embodiments of any aspect of the invention, the polymeric stabilizer is formed in-situ during the preparation of the encapsulated perfume composition.

In specific embodiments of any aspect of the invention, the shell of at least one core-shell type microcapsule is a thermosetting aminoplast formed by the reaction of a polyfunctional amine and an activated alkene, and more specifically still melamine and a (meth)acrylic acid ester.

In particular embodiments of any aspect of the invention, the shell of at least one core-shell microcapsule is a polyurea shell formed by the reaction of a polyfunctional amine and at least one isocyanate, in particular two structurally different isocyanates.

In specific embodiments of any aspect of the invention, the encapsulated perfume composition does not contain aldehydes and, more specifically, does not contain formaldehyde.

These and other aspects and embodiments of the invention will become better understood in light of the following detailed description of the invention.

Detailed description of the invention

Core-shell microcapsules are typically prepared by providing an encapsulating shell around oil droplets dispersed in an aqueous phase in the form of an oil-in-water emulsion. These oil-in-water emulsions are usually stabilized with polymeric stabilizers, which may also be referred to as protective colloids or polymeric emulsifiers, and are usually polydisperse. One simple way to determine the polydispersity of an emulsion is to measure the droplet size distribution according to techniques well known in the art and calculate the spread of this distribution given by equation (1)

where Dv(10) is the volume-average diameter at which 10% of the total droplet volume consists of droplets smaller than this value, Dv(50) is the median droplet diameter of the volumetric distribution and corresponds to the volume-average diameter at which 50% of the total droplet volume consists of droplets with a diameter less than this value, and the Dv(90) value is the diameter at which 90% of the sample volume consists of droplets with a diameter less than this value.

The size and size distribution of the microcapsules can be determined in a manner known in the art. A specific method for measuring particle size is light scattering. Light scattering measurements can be made using the Malvern Mastersizer 2000S and Mie scattering theory. The principle of Mie theory and information on how light scattering can be used to measure the size of droplets can be found, for example, in N.S. van de Hulst, Light scattering by small particles. Dover, New York, 1981. The primary information provided by static light scattering is the angular dependence of light scattering intensity, which in turn is related to droplet size and shape. However, in the standard mode of operation, the size of a sphere having a size equivalent to the size of the diffraction object, regardless of the shape of this object, is calculated using the Malvern proprietary software supplied with the instrument. In the case of polydisperse samples, the angular dependence of the total scattering intensity contains information about the size distribution in the sample. The result is a bar graph representing the total volume of droplets belonging to a given size class versus capsule size, with an arbitrary number of 50 size classes to choose from. The resulting size is thus referred to as the volume average particle size.

In the experiment, a few drops of the suspension are added to a circulating stream of degassed water flowing through a scattering cell. Under these dilution conditions, the angular distribution of scattering intensity is measured and analyzed using proprietary Malvern software supplied with the instrument to provide the average size and size distribution of the droplets present in the sample. In the case of a unimodal (monodisperse) distribution of droplets, the percentiles Dv(10), Dv(50) and Dv(90) are used as characteristics of the size distribution of droplets, while Dv(50) corresponds to the median of the distribution and is taken as a measure of the volume average size microcapsules.

For a core-in-shell process using such an oil-in-water emulsion base, it is natural that the size distribution of the microcapsules obtained at the end of the process is essentially the same as the size distribution of the droplets in the emulsion. Therefore, solving the problem of polydispersity at the emulsion level is a defining step in the production of microcapsules having low polydispersity.

However, attempts to create low polydispersity emulsion droplets using standard emulsification techniques and prior art surfactant/polymer stabilizers have been unsuccessful, as too wide droplet size distributions have been systematically obtained using these techniques. Applicant believes, though not intending to be bound by theory, that this wide distribution may be due to the inability of conventional polymeric stabilizers to provide sufficient stability to the oil-water interface.

Examples of conventional polymeric stabilizers are described in US 8119587 and include LUPASOL PA 140 and copolymers formed from the reaction of ethylenically unsaturated monomers and maleic anhydride such as ZeMac E400.

According to the present invention, new polymeric stabilizers have been found which have a high emulsifying power which allows the formation of very small oil droplets with low polydispersity at low agitation speed. Moreover, the formed oil-water interface appears to provide a very stable platform around which thermoset resin sheaths can be formed.

The use of a polymeric stabilizer as defined herein provides encapsulated perfume compositions containing core-shell microcapsules that exhibit at least one, and preferably all, of the following features:

I. Microcapsules are formed with a perfume ingredient loading that is at least 35 wt. % and preferably at least about 40 wt. %, based on the total weight of the suspension (i.e. microcapsules + aqueous suspending medium).

II. The perfume ingredient can be encapsulated with a very high encapsulation yield, for example, more than 90 wt. % and preferably more than 95 wt. % microcapsules is an encapsulated perfume ingredient.

III. The microcapsules show a balance of stability and release characteristics that is comparable to traditional melamine-formaldehyde capsules.

IV. The microcapsules have an average particle size Dv(50) of 30 microns or less, preferably 20 microns or less, and a polydispersity having a spread of less than 1.5, preferably less than 1.3, more preferably less than 1.2. Moreover, the aforementioned particle size and polydispersity can be achieved at low to moderate mixing speeds.

Stability and release characteristics can be assessed by performing olfactory assessments such as those described in Example 6 below in this document.

Low to moderate agitation speeds are understood to mean, for example, less than 1000 rpm, preferably on the order of about 100 to 1000 rpm, more preferably from about 500 to 700 rpm, for example 600 rpm, in a vessel having a volume of 1 liter, equipped with an agitator with a cross, with an inclined bar, and having a ratio of the agitator diameter to the reactor diameter of 0.7.

The mixing device may include a turbine, a Mig mixer, or the like. One skilled in the art, however, will readily appreciate that such agitation conditions may vary depending on reactor size and slurry volume, precise agitator geometry, agitator diameter to reactor diameter ratio. For example, for a Mig agitator with an agitator to reactor diameter ratio of 0.5 to 0.9 and slurry volumes of 0.5 to 8 tons, the preferred agitation speed for the purposes of the present invention is 150 rpm to 50 rpm.

With respect to feature (III), the leakage stability of core-shell microcapsules can be evaluated according to techniques well known in the art. A convenient method for evaluating the leakage stability of microcapsules in extractive media is described in the examples below in this document.

The high loading and good stability of the microcapsules enables the production of encapsulated perfume compositions in an economical manner, which can provide excellent perfume benefits. In particular, the microcapsules show good breakability, which is particularly advantageous in hair care applications where good post-combing performance is a particularly desirable feature. Moreover, since smaller microcapsules are believed to be deposited with higher efficiency on a surface such as a tissue surface, the fact that the microcapsules of the present invention can be formed with a characteristic small particle size and low polydispersity is considered to be particularly advantageous.

The polymeric stabilizers of the present invention stabilize the dispersed oil droplets, preventing the droplets from sticking together and keeping them well suspended in the dispersion medium. In this way, polymeric stabilizers provide a stable and multi-functional platform on which to deposit various shell chemicals on perfume ingredient oil droplets to form novel core-shell microcapsules.

The polymeric stabilizer of the present invention is the reaction product of a polymeric surfactant and a silane that contains a functional group that can form a covalent bond with the sheath material. Thus, the polymeric stabilizer not only acts as an emulsifier to produce stable emulsions, it can also act as a covalent binding agent to promote the bonding of shells and dispersed oil droplets, resulting in better quality core-shell microcapsules. Functionalization of the polymeric stabilizer such that it can covalently bond to the shell is a hallmark of the present invention.

Polymeric surfactants which are particularly suitable for the purpose of the present invention include copolymers which are the reaction product of maleic anhydride and an olefin monomer such as ethylene, isobutylene or styrene. Examples of such copolymers include ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, and styrene-maleic anhydride copolymer. A particularly preferred copolymer is an ethylene-maleic anhydride copolymer, commercial grade of which is available under the trade name ZeMacE400. The maleic anhydride copolymer may be used alone or, alternatively, combinations of maleic anhydride copolymers may be used.

The maleic anhydride copolymer may be provided for use in the present invention in a hydrolysed form, wherein the anhydride may be in its free acid form, or its salt form, or mixtures thereof.

If a maleic anhydride copolymer is used, it is particularly preferred if it is pre-hydrolyzed before being used in the emulsification process. Hydrolysis can be achieved by dissolving maleic anhydride in an aqueous medium, optionally at an elevated temperature, for example from about 85 to 90° C., for an appropriate period of time. Typically, for the implementation of hydrolysis, the appropriate period of time is 2 hours. After the polymer is dissolved under these conditions, the pH of the solution is typically less than 3, which may indicate that hydrolysis has occurred. Moreover, analysis by infrared spectroscopy reveals that the usual absorption bands corresponding to the anhydride group have disappeared.

As stated above herein, the maleic anhydride copolymer in hydrolyzed form can be provided in its free acid form, or in its salt form, or as a mixture of its free acid form and its salt. The relative amount of its free acid form and salt depends on the pH of the aqueous medium. More specifically, the maleic anhydride copolymer is used in aqueous solution at a pH of from about 2 to about 7, more specifically from about 4 to about 5, at which the maleic anhydride copolymer exhibits optimal emulsifying properties.

The maleic anhydride copolymer in hydrolysed form can be provided as a mixture of its free acid form and its salt form with monovalent counterions such as lithium, sodium, potassium, or ammonium counterions.

The silane used in the preparation of the polymeric stabilizer may be selected from a compound of formula I

in which R ₁ , R ₂ and R ₃ independently represent C ₁ -C ₄ linear or branched alkyl or alkene, in particular methyl or ethyl, and R ₄ represents C ₁ -C ₁₂ , preferably C ₁ -C ₄ , linear or branched alkyl or alkene containing a functional group. Particularly preferred are aminosilanes. The functional group may thus be an amine, in particular a primary, secondary or tertiary amine.

When the functional group is a primary amine, it may be a terminal primary amine. Then R ₄ is preferably C ₁ -C ₈ , even more preferably C ₁ -C ₄ linear terminal primary aminoalkyl residue. Specific aminosilanes in this category are selected from the group consisting of aminomethyltriethoxysilane, 2-aminoethyltriethoxysilane, 3-aminopropyltriethoxysilane, 4-aminobutyltriethoxysilane, 5-aminopentyltriethoxysilane, 6-aminohexyltriethoxysilane, 7-aminoheptyltriethoxysilane and 8-aminooctyltriethoxysilane, most preferably 3-aminopropyltriethoxysilane. The aminosilane and the maleic anhydride copolymer which react and form the polymeric stabilizer can be combined in a widely varied amount. However, it is preferred that the weight ratio of polymeric surfactant, and more specifically maleic anhydride copolymer, to silane is from about 1/0.05 to about 1/1, more specifically from about 1/0.1 to about 1/0, 7, even more specifically from about 1/0.3 to about 1/0.4, such as 1/0.33.

Due to the alkoxy functional groups present on the aminosilane, the polymeric stabilizer not only acts as an emulsifier to produce stable emulsions, it can also act as a covalent binding agent to promote the bonding of shells and dispersed oil droplets, resulting in core type microcapsules. - best quality cover.

Functionalization of the polymeric stabilizer such that it can be covalently bonded to the shell, for example by polycondensation of alkoxysilane moieties, is a hallmark of the present invention.

According to the process of the present invention, microcapsules are formed when resin shells are formed which surround, or at least partially surround, the emulsion droplets.

In principle, a shell of any chemical composition can be formed around the droplets of the perfume ingredient, which are stabilized by the polymeric stabilizer of the present invention. The shell chemistry may be conventional, such as melamine-formaldehyde, urea-formaldehyde, polyurea, or polyacrylate resins.

In specific embodiments of the invention, the shell can be formed by polycondensation of polyfunctional amine precondensates with aldehydes and in particular hydroxymethylmelamine and formaldehyde.

In specific embodiments of the invention, the shell can be formed by the reaction of a polyfunctional amine and at least one isocyanate, in particular two structurally different isocyanates.

In other specific embodiments, the shell can be formed by chain propagation polymerization via radicals and in particular the reaction of divinylbenzene (DVB) and (meth)acrylic acid or its esters such as methyl methacrylate. Microcapsules containing a shell of thermosetting resin containing a copolymer of DVB and methyl methacrylate are specific embodiments of the present invention.

In particularly preferred embodiments of the present invention, the shell may be formed by polyaddition reaction of a shell-forming material containing a plurality of activated olefinic double bonds with a shell-forming material containing a plurality of nucleophilic functional groups capable of reacting with the activated olefinic double bonds.

The shell-forming material containing nucleophilic functional groups may be a linear or branched aliphatic, aromatic, cyclic aliphatic, heterocyclic, heteroaromatic, organosilane material, or mixtures of any of the above structures. The material may be monomeric, oligomeric or polymeric. Nucleophilic functional groups can be selected from amino groups, and in particular primary or secondary amino groups, thiol groups, hydroxyl groups and imino groups. Particularly preferred such shell-forming materials are polyfunctional amines selected from linear or branched aliphatic amines, or amino-functionalized aliphatic or aromatic heterocycles. Even more specifically, the shell material is a di- or triamino-substituted heterocycle selected from melamine (2,4,6-triamino-1,3,5-triazine), 3,5-diamino-1,2,4-triazole, 2,4-diamino-6-phenyl-1,3,5-triazine or 6-methyl-1,3,5-triazine-2,4-diamine, 1,2-phenylenediamine, 1,3-phenylenediamine or 1, 4-phenylenediamine or mixtures thereof.

The polyimines also react with the olefinic double bonds of the first shell-forming monomer and are therefore also suitable for preparing the microcapsules of the present invention.

The shell-forming material containing a plurality of activated olefinic double bonds can be any Michael acceptor that is capable of interacting with the aforementioned shell-forming material containing a plurality of activated olefinic double bonds. The Michael acceptor may contain an olefinic double bond in conjugation with any suitable electron withdrawing group such as a nitrile, keto, amido or ester group. The shell-forming material may be a monomer, an oligomer, or a polymer. Particularly preferred shell materials are di-, tri- or tetrafunctional amides or acrylates, although polyfunctional acrylates are preferred. Suitable polyfunctional acrylates are at least difunctional acrylates and include, but are not limited to, C ₁ -C ₂₄ alkyl ester or acrylic acid esters and/or methacrylic acid.

In specific embodiments, the shell-forming monomers can be selected from pentaerythritol tetraacrylate (PETA), pentaerythritol triacrylate (PETIA), 1,4-butanediol diacrylate (BDA-2), ethylene glycol dimethacrylate (EDGMA), trimethylol propane triacrylate (TMPTA) and hexanediol diacrylate (HDDA), ((2,4, 6-trioxocyclohexane-1,3,5-triyl) tris (oxy) (tris (ethane-2,1-diyl) triacrylate (TOSTA), tris (2-acryloyloxyethyl) isocyanurate, 1,3,5-triacryloylhexahydro-1, 3,5-triazine (TANNT) or mixtures thereof.

According to preferred embodiments of the invention, the shell-forming monomers are the polyfunctional amines described above, and in particular melamine, and the Michael acceptor described above, which is more specifically the polyfunctional acrylate. Both the polyfunctional amine and the polyfunctional acrylate must be at least difunctional, that is, they must contain at least two reactive amino groups or at least two reactive acrylate groups, respectively. Moreover, at least one of the polyfunctional amine and the polyfunctional acrylate must be at least trifunctional to form a crosslinked network.

In preferred embodiments of the present invention, the shell-forming monomers are selected from a polyfunctional amine such as melamine, 1,2-phenylenediamine, 1,3-phenylenediamine and 1,4-phenylenediamine or mixtures thereof, and a polyfunctional acrylate such as tris(2-acryloyloxyethyl) isocyanurate; and 1,3,5-triacryloylhexahydro-1,3,5-triazine. Without wishing to be bound by any particular theory, combinations of any of these particular polyfunctional amines and these particular polyfunctional acrylates are believed to be particularly advantageous because they can form a planar and substantially two-dimensional resin structure.

Microcapsules based on this chemistry have the features described herein above and are particularly advantageous because they do not contain formaldehyde.

According to the method of the present invention, if required, the functional coating can be applied to the thermosetting resin shell of the microcapsules of the core-shell type. The functional coating may completely or only partially cover the shell of the microcapsule. Whether the functional coating is charged or uncharged, its main purpose is to change the properties of the surface of the microcapsule to achieve the desired effect, such as enhancing the deposition of the microcapsules on the surface to be treated, such as tissue, human skin, hair, and the like. Functional coatings can be applied to already formed microcapsules after their formation, or they can be physically embedded in the microcapsule shell during shell formation. They can be attached to the shell by physical forces, physical interactions such as hydrogen bonding, ionic interactions, hydrophobic interactions, electron transfer interactions, or they can be covalently bonded to the shell.

If the functional coating is to be physically bonded to the shell, the chemical structure of the coating is to some extent determined by its compatibility with the chemical composition of the shell, since there must be some bond to the microcapsule shell.

If the functional coating is to be covalently bonded to the shell, this can be facilitated by incorporating into the shell materials bearing functional groups that are capable of reacting with the coating material.

For example, if a core-shell microcapsule shell as described herein is prepared using a di-, tri- or tetra-functional (meth)acrylate shell-forming monomer, then any residual acrylate functionality present in the shell associated with the acrylate shell-forming monomer, which does not react with the polyfunctional amine during shell formation may react with the coating material to covalently bond the latter to the shell.

Suitable coating materials may be based on polysaccharides, polypeptides, polycarbonates, polyesters, polyolefins (vinyl, acrylic, acrylamide, polydiene), polyester, polyester, polyurethane, polyoxazoline, polyamine, siloxane, polyphosphazine, polyaromatic compounds, polyheterocyclic compounds, etc. P. A more detailed list of coating materials that can be used to coat microcapsules can be found in the patent literature, for example EP 1797947, which describes coating materials that can be used as deposition aids, which is incorporated herein by reference.

Particularly preferred coating materials can be selected from the group consisting of polymethyl methacrylate, polydimethylaminoethyl methacrylate, polybutyl methacrylate, polydiallyldimethylammonium chloride, and mixtures thereof.

If the coating material is a polymer, it can be formed in-situ during the coating process by polymerizing coating material monomers that contain olefinic double bonds. More specifically, suitable monomers can be added to a suspension of core-shell microcapsules formed according to the method described herein and polymerized as well as reacted with the aforementioned residual acrylate functionality in the shell in order to create a polymeric coating material that is covalently associated with the shell and which at least partially covers it.

Suitable monomers for this purpose include, but are not limited to, acrylates such as methyl methacrylate, butyl methacrylate, methacrylic acid, dimethylaminoethyl methyl methacrylate (DMAEMA), and diallyldimethylammonium chloride (DADMAC).

The invention will be better understood with reference to a description of the methods for preparing the above encapsulated perfume compositions, the methods, as well as encapsulated perfume compositions made according to these methods, are additional aspects of the present invention.

In a specific aspect, the invention provides a method for forming an encapsulated perfume composition as described herein, comprising at least one core-shell microcapsule dispersed in a dispersing medium, said method comprising the steps of:

I. Formation of an oil-in-water emulsion containing at least one drop of oil containing a perfume ingredient in an aqueous external phase, in the presence of a polymer stabilizer, and

II. reacting the shell-forming materials present in the emulsion and forming, at the oil-water interface, a shell of thermosetting resin surrounding or at least partially surrounding said at least one perfume ingredient-containing oil droplet, and

III. possibly at least partially coating the core-shell microcapsules of the functional coating material.

When performing stage (I) in the embodiments of the invention, the polymeric stabilizer can be formed in-situ and, more specifically, during or after the emulsification step and before the encapsulation step.

The in-situ formation of a polymeric stabilizer is accomplished by reacting a polymeric surfactant with a silane, both of which are defined herein above.

Proper mixing speed and mixer geometry can be selected to obtain the desired average droplet size and droplet size distribution. The present invention is characterized in that the polymer stabilizer has a particularly high surface activity and can promote the formation of dispersed droplets with the desired small size and low polydispersity.

The method of the present invention is characterized in that, in a one liter vessel equipped with a cross bar stirrer and having a stirrer diameter to reactor diameter ratio of 0.7, microcapsules having an average particle size D(50) of 30 microns or less can be formed, preferably 20 microns or less, and a polydispersity parameter of less than 1.5, preferably less than 1.3, more preferably less than 1.2, at an agitation speed of less than 1000 rpm, preferably on the order of about 100 to about 1000 rpm, more preferably from about 500 to 700 rpm, for example, 600 rpm, using a turbine, a cross bar mixer such as a Mig mixer, and the like. Preferably, the Mig stirrer is operated at 600±50 rpm. However, one of ordinary skill in the art will readily appreciate that such agitation conditions may vary depending on reactor size and slurry volume, precise agitator geometry, agitator diameter to reactor diameter ratio. For example, for a Mig agitator with an agitator to reactor diameter ratio of 0.5 to 0.9 and slurry volumes of 0.5 to 8 tons, the preferred agitation speed for the purposes of the present invention is 150 rpm to 50 rpm.

When an oil-in-water emulsion is formed, the maleic anhydride copolymer is added to the aqueous external phase and the aminosilane is mixed into the oil phase. Their separation is an optimization of the method to control the degree of hydrolysis of the silane and ensure that the silane and the maleic anhydride copolymer react at the interfaces of oil and water in an optimal way with the formation of polymeric stabilizer in-situ. If the silane is hydrolyzed too quickly, it tends to self-condensate. The use of silane in the oil phase promotes its reaction with the polymeric surfactant at the oil-water interface rather than its self-condensation.

In order to provide optimal reaction conditions for the compound of aminosilane and maleic anhydride, the pH of the mixture is raised to about 3.5-7, such as 4.5 or 6. This can be achieved by adding a suitable base. A dilute solution (20%) of ammonia is suitable for this, although other bases such as dilute sodium hydroxide can be used. The entire process can be carried out over a period of time from about 1 hour to 3 hours, preferably 2±0.5 hours, and at ambient or slightly elevated temperature, eg 35±5°C. The polymeric stabilizer thus formed in-situ becomes bound to the oil/water interface to form at least a partial layer around the oil droplets, stabilizing them and preventing them from sticking together.

The dispersed oil droplets, stabilized with a polymeric stabilizer, form multi-functional platforms onto which various shell-forming chemicals can be deposited to form new core-shell microcapsules.

Although a variety of shell chemicals can be applied to the oil droplets to form core-shell microcapsules of varying chemistry, methods for forming shells of preferred chemistry are described below to further illustrate the invention.

Each of the shell-forming monomers may be added before, during, or after the formation of the oil-in-water emulsion. Moreover, the shell-forming monomers can be added to the reaction mixture simultaneously, individually or sequentially.

The reaction of the shell-forming monomers in the oil-in-water emulsion is initiated by establishing physical and/or chemical conditions in the emulsion. For example, the pH and temperature of an oil-in-water emulsion can be adjusted. Depending on the chemistry used, the pH can be maintained in the acidic range, eg 2.5 to 7, eg 4±0.2. Alternatively, the pH may be raised above neutral, for example in the range of about 7.5 to about 10, preferably about 8 to about 9, and more preferably 8.5 ± 0.2. The pH adjustment step may be carried out by adding an appropriate amount of a suitable acid or base, which may be in the form of a dilute solution (eg 10 or 20%) of hydrochloric acid or ammonia, but other acids and bases may be used. Alternatively, an increase in the temperature of the reactor may be used to initiate the reaction. In order to avoid any undesired premature reactions of the shell monomers, it is particularly preferred that the pH adjustment and/or temperature increase is carried out after the addition of the shell monomer, such as a shell monomer containing a plurality of olefinic double bonds, which will typically be a polyfunctional acrylate.

In addition to raising the pH of the oil-in-water emulsion, the temperature of the emulsion can be raised to a reaction temperature of about 40°C to about 100°C, preferably from about 50 to 95°C, more preferably from about 70 to 90°C, for example , 80±5°С. Heating can be maintained for a period of time sufficient to at least partially initiate the reaction of the shell-forming monomers at the oil/water interface to form shells of thermosetting resin around the dispersed oil droplets and thereby form an encapsulated composition in the form of a suspension of core-shell type microcapsules. The time for maintaining this elevated temperature may be from about 1 to 10 hours, more specifically from 2 to 6 hours, even more specifically from 2.5 to 4 hours, for example 3 hours.

The time taken to reach the reaction temperature may be from about 15 minutes to more than 2 hours. Preferably, the elapsed time is 1.5±0.5 hours.

According to the process described herein, microcapsules can be obtained which show good retention of their core contents, but are also quite brittle. However, the microcapsules are robust enough that they exhibit low levels of leakage during storage, even in extractive media, but when used at a high proportion can break relatively easily to release the contents of their cores. This is particularly advantageous in encapsulated perfume applications and more particularly in encapsulated perfume applications for laundry.

Without wishing to be bound by a particular theory, it is believed that operating within the process parameters described herein, including the choice of reactants and, in particular, the control of the degree and/or duration of heating in the manner described, it is possible to control the reaction of the shell-forming monomers and create relatively thin and uniform resin shells. , which resist leakage, but which can be destroyed by only light or moderate shear.

Once the microcapsules have formed, the encapsulated composition may be cooled to room temperature. Preferably, the cooling time is at least one hour, more specifically at least 2 hours, such as 2.5±0.5 hours. It is believed that when cooled slowly in this way, the resin is able to further self-order by tempering, which can also affect the uniformity of the resin shells and therefore contribute to the properties of the microcapsules in use.

Before, during or after cooling, the encapsulated composition may be further processed. Further processing may include treating the composition with one or more antimicrobial preservatives that are well known in the art. Post-treatment may also include the addition of a suspending agent, such as a hydrocolloid suspending agent, to aid in the formation of a stable physical dispersion of the microcapsules and to prevent any emulsion breakdown or sticking or anything else. Any additional additives that may be required, or conventional in the art, can also be added at this stage.

The resulting encapsulated composition, presented in the form of a suspension of microcapsules suspended in an aqueous suspending medium, can be included as such in a consumer product base. However, if desired, the suspension can be dehydrated to provide the encapsulated composition in dry powder form. Dehydration of the microcapsule suspension is a conventional process and can be performed according to techniques known in the art such as spray drying, evaporation or lyophilization. Typically, as is customary in the art, the dried microcapsules are dispersed or suspended in a suitable powder such as powdered silica and the like, which can act as a bulking agent, flow agent, and the like. Such suitable powder may be added to the encapsulated composition before, during or after the drying step.

According to preferred embodiments of the invention, the shell-forming materials are selected from the polyfunctional amines described above, and in particular melamine, and the Michael acceptor described above, and more particularly the polyfunctional acrylate. Both the polyamine and the polyfunctional acrylate must be at least difunctional, that is, they must contain at least two reactive amino groups or at least two reactive acrylate groups, respectively. Moreover, at least one of the polyamine and the polyfunctional acrylate must be at least trifunctional.

The case where a polyfunctional amine and a polyfunctional acrylate are used as the shell-forming monomers is a specific method for forming the encapsulated composition of the present invention, which includes the steps of:

- the formation of an oil-in-water emulsion containing a polymeric stabilizer, wherein the oil contains at least one perfume ingredient and the aqueous phase has a pH of from about 3.5 to 7, for example 4.5 or 6, preferably at an elevated temperature, more than preferably 35±5°C,

- maintaining the emulsion under stirring and at the above temperature for a period of time up to 2 hours or more, for example, 2±0.5 hours.

- adding with stirring shell-forming monomers containing a polyfunctional amine, more specifically melamine, 1,2-phenylenediamine, 1,3-phenylenediamine or 1,4-phenylenediamine, or a mixture thereof, and a polyfunctional acrylate selected from the group consisting of ((2 ,4,6-trioxocyclohexane-1,3,5-triyl)tris(oxy)(tris(ethane-2,1-diyl)triacrylate, tris(2-acryloyloxyethyl)isocyanurate, 1,3,5-triacryloylhexahydro-1, 3,5-triazine or mixtures thereof, where the polyfunctional acrylate is preferably added before adding the polyfunctional amine,

- adjusting the pH of the emulsion to a pH of from about 7.5 to about 10, preferably from 8 to 9, for example 8.5 ± 0.2, by adding a base, where the pH adjustment is preferably carried out between the addition of the polyfunctional acrylate and the polyfunctional amine,

- heating the emulsion to a reaction temperature of from about 40 to about 100°C, preferably from about 50 to 95°C, more preferably from about 70 to 90°C, for example, 80±5°C, where the temperature is raised to the reaction temperature over a period of time from about 15 minutes to about 2 hours or more, for example 1.5±0.5 hours, said heating step may be performed before, during or after the pH adjustment step,

- maintaining the emulsion at the reaction temperature for a period of time sufficient to at least partially carry out the reaction of the shell-forming monomers at the interface of oil and water with the formation of cross-linked resin shells around the dispersed oil droplets, whereby a suspension of microcapsules of the core-shell type is formed, where the period the time may be from about 0.5 to 10 hours, preferably from 2 to 6 hours, more preferably from 2.5 to 4 hours, for example 3 hours,

- cooling the suspension to room temperature, for example, over a period of time from about 15 minutes to about 2 hours or more, for example, 2±0.5 hours,

- optionally treating the suspension before, during or after the cooling step by adding an antimicrobial preservative, a suspending agent to aid the stability of the microcapsule dispersion in the suspension, and any other adjuvants that may be required or are conventional in the art, and

possibly dehydrating the suspension to provide an encapsulated composition in powder form.

With respect to the order in which the shell monomers are added, the polyacrylate shell monomer can be added before, during, or after the formation of the oil-in-water emulsion, although it is preferred to add it after it has formed. Moreover, this monomer is preferably added after the addition of the polyfunctional amine shell-forming monomer.

The polyfunctional amine can be dissolved in the aqueous phase or used in solid form, and a method for forming microcapsules and encapsulated compositions containing them, in which the polyfunctional amine is used in solid form, is a specific embodiment of the present invention. It has been found that the use of a solid polyfunctional amine is particularly advantageous when the polyfunctional amine used as the shell-forming monomer is melamine. It was surprising that melamine in solid form could be used in this way. However, not only is it possible to carry out the polyaddition reaction at the interface of oil and water with melamine in solid form, but if dissolution of the melamine is not required, an undesirable and industrially impractical dilution step can be avoided. Without wishing to be bound by any particular theory, it is believed that the solid particles of a poorly soluble polyfunctional amine such as melamine are adsorbed or dissolved at the oil-water interface and thus become available at the site of the polyaddition reaction with other shell-forming monomers and in turn , the reaction seems to activate the process of absorption or dissolution of the polyfunctional amine at the interface between oil and water.

The polyfunctional amine in solid form can be used in the form of a powder, or it can be used as a dispersion of a solid in an aqueous phase.

If they have not already been added to the oil-in-water emulsion, the shell-forming monomers can be added to the oil-in-water emulsion with agitation according to the addition sequence specified herein above.

According to another particular embodiment of the invention, the shell-forming monomers are selected from the precondensates of the polyfunctional amine, more particularly the precondensates of melamine and urea with aldehydes, and in particular with formaldehyde. The method for preparing capsules based on such shell-forming monomers is essentially the same as the method described above in this document for polyfunctional amines and polyfunctional acrylates, except that (i) in this case, the pH range of the reaction is in the acidic region, more specifically from 3 to 6, for example 4.4±0.5. Additionally, according to this particular embodiment, a formaldehyde scavenger can be used to reduce the level of formaldehyde in the final slurry, where the formaldehyde scavenger can be added before, during, or after the slurry is cooled to room temperature.

Alternatively or additionally, during the formation of the thermoset resin shell, if desired, a monofunctional acrylate monomer may be added to the reaction mixture. Thus, the monofunctional acrylate monomer is incorporated into the shell as the shell is in the process of being formed. While it is possible to add the monofunctional acrylate monomer at the same time as adding the melamine, it is preferably added at some point in time after the addition of the melamine. More specifically, it is added at some point in time after the addition of melamine and before the shell is fully formed.

According to another specific embodiment of the invention, the shell can be formed by free radical chain growth polymerization and in particular the reaction of divinylbenzene (DVB) and (meth)acrylic acid or its esters such as methyl methacrylate. Microcapsules containing a shell of thermosetting resin containing a copolymer of DVB and methyl methacrylate form specific embodiments of the present invention.

The method for preparing microcapsules based on such free radical polymerization mechanisms is essentially the same as the method described herein above for polyfunctional amines and polyfunctional acrylates, except that (i) in this case the pH range of the reaction is in the acidic region. , more specifically from 3 to 6, eg 4.4±0.5, and (ii) free radical polymerization is caused by a radical initiator. The initiator may be oil-soluble, such as diazo compounds and diacyl peroxides, or water-soluble, such as metal peroxodisulfate, metal peroxodiphosphates, or hydrogen peroxide. In a specific embodiment, both oil-soluble and water-soluble initiators are used.

The case where a polyfunctional amine and an isocyanate are used as the shell-forming monomers constitutes a specific method for forming the encapsulated composition of the present invention. This method includes the steps:

- formation of an oil-in-water emulsion containing a polymeric stabilizer, an oil containing at least one perfume ingredient, and an aqueous phase,

- adding at least one polyisocyanate to the oil-in-water emulsion, in particular adding a polyisocyanate (A) and a polyisocyanate (B) which is different from the polyisocyanate (A),

- adding at least one polyfunctional amine to the oil-in-water emulsion,

- the implementation of the formation of shells around the drops of the emulsion "oil in water" to obtain a dispersion of microcapsules.

The oil-in-water emulsion can be formed at a pH of 3.5 to 7, preferably 4.5 to 6. The formation can be carried out at an elevated temperature, more specifically 35±5°C. The oil-in-water emulsion can, if necessary, be maintained under stirring and at the above temperature for a period of time up to 2 hours or more, for example 2±0.5 hours.

Organic isocyanates are compounds in which the isocyanate group is linked to an organic moiety (R-N=C=O or R-NCO). Within the scope of the present invention, polyisocyanates (or polyfunctional isocyanates) are organic isocyanates with two or more (eg 3, 4, 5, etc.) isocyanate groups per molecule. Suitable polyisocyanates are, for example, aromatic, alicyclic or aliphatic.

Anionically modified polyisocyanates contain at least two isocyanate groups and at least one functional group that is anionic or anionic. "Anionic functional group" is a group that can become anionic depending on the chemical environment, such as pH. Suitable anionic or anionic groups are, for example, carboxylic acid groups, sulfonic acid groups, phosphonic acid groups and their salts.

The anionically modified polyisocyanate (A) may contain one or more sulfonic acid groups or salts thereof. Suitable salts may be sodium, potassium or ammonium salts. Ammonium salts are preferred.

Preferably, the anionically modified polyisocyanate (A) is obtained by reacting the polyisocyanate with 2-(cyclohexylamino)-ethanesulfonic acid and/or 3-(cyclohexylamino)-propanesulfonic acid.

More preferably, the anionically modified polyisocyanate (A) is prepared by reacting the polyisocyanate with 2-(cyclohexylamino)-ethanesulfonic acid and/or 3-(cyclohexylamino)-propanesulfonic acid, wherein the polyisocyanate is selected from hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'- diisocyanate, 2,4- or 2,6-toluene diisocyanate and mixtures of their isomers, diphenylmethane diisocyanates, biurets, allophanates and/or isocyanurates of the above polyisocyanates.

The anionically modified polyisocyanate (A) can in each case be selected from anionically modified hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexamethylene diisocyanate isocyanurate, and mixtures thereof.

Preferably the anionically modified polyisocyanate (A) has:

- an average isocyanate functionality of at least 1.8,

- the content of isocyanate groups (in terms of NCO, molecular weight 42) from 4.0 to 26.0 wt. %,

- the content of sulfonate groups (in terms of SO ₃ , molecular weight 80) from 0.1 to 7.7 wt. % and

- possible content of ethylene oxide units bound in polyester chains (in terms of C ₂ H ₂ O, molecular weight 44), from 0 to 19.5 wt. %, where the polyester chains contain a statistically average value of 5 to 55 units of ethylene oxide.

In particular, the anionically modified polyisocyanate (A) can be selected from anionically modified hexamethylene diisocyanate, anionically modified hexamethylene diisocyanate, anionically modified hexamethylene diisocyanate isocyanurate, and mixtures thereof.

In a particularly preferred embodiment, the anionically modified polyisocyanate (A) may correspond to formula II.

Formula II shows a commercially available anionically modified polyisocyanate which is a modified hexamethylene diisocyanate isocyanurate marketed by Covestro under the trademark Bayhydur® XP2547.

In the method of the present invention, the polyisocyanate (B) may be a non-ionic polyisocyanate.

The nonionic polyisocyanate may be selected from the group consisting of 1,6-diisocyanatohexane, 1,5-diisocyanato-2-methylheptane, 1,5-diisocyanato-3-methylheptane, 1,4-diisocyanato-2,3-dimethylbutane, 2-ethyl -1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,4-diisocyanatobutane, 1,3-diisocyanatopropane, 1,10-diisocyanatodecane, 1,2-diisocyanatocyclobutane, bis(4-isocyanatocyclohexyl)methane, 3,3,5 -trimethyl-5-isocyanatomethyl-1-isocyanatocyclohexane, isophorone diisocyanate (IPDI), hexamethylene-1,6-diisocyanate (HDI), hydrogenated 4,4-diphenylmethane diisocyanate (HMDI).

The polyisocyanate (B) can also be a non-ionic oligomer based on the above isocyanate monomers, such as, for example, 1,6-diisocyanatohexane homopolymer. All of these monomers and oligomers are sold under the trade name Desmodur® by Covestro AG.

Preferably, the nonionic polyisocyanate (B) is selected from hexamethylene diisocyanate, tetramethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 2,4- or 2,6-toluene diisocyanate and mixtures of their isomers, 2,4'- and 4,4'-diphenylmethane diisocyanate and mixtures its isomers, xylylene diisocyanate (eg Desmodur® quix 175 sold by Covestro), optionally as trimethylol propane adduct (TMP) (eg sold under the trade name Takenate™ D-110N), biurets, allophanates and/or isocyanurates of the aforementioned polyisocyanates or their mixtures.

A preferred commercially available nonionic polyisocyanate (B) is dicyclohexylmethane diisocyanate, in particular sold by Covestro AG under the trade name Desmodur® W1.

A preferred commercially available non-ionic polyisocyanate (B) is hexamethylene diisocyanate, in particular sold by Covestro AG under the trade name Desmodur® N3200.

A preferred commercially available non-ionic polyisocyanate (B) is isophorone diisocyanate, in particular sold by Covestro AG under the trade name Desmodur® Z.

These polyisocyanates have the advantage of being non-aromatic and therefore more stable and less prone to oxidation, while still being highly reactive with polyamines and a suitable molecular structure to form impermeable encapsulating resins.

In a preferred embodiment of the present invention, the anionically modified polyisocyanate (A) is selected from anionically modified hexamethylene diisocyanate, anionically modified isophorone diisocyanate, anionically modified dicyclohexylmethane-4,4'-diisocyanate, anionically modified hexamethylene diisocyanate isocyanurate and mixtures thereof, and nonionic polyisocyanate (B) is selected from hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexamethylene diisocyanate isocyanurate and mixtures thereof.

The weight ratio of anionically modified polyisocyanate (A) to nonionic polyisocyanate (B) may be from 10:1 to 1:10, more preferably from 1:1 to 1:5 and in particular from 1:2 to 1:4. These weight ratios provide the resin having the highest impermeability and therefore the most suitable for encapsulation.

In the context of the present invention, the term "polyfunctional amine" means amines which contain at least two NCO-reactive groups, wherein at least one of the NCO-reactive groups is a primary or secondary amino group. When a polyfunctional amine contains only one primary or secondary amino group, it contains one or more additional functional groups that are capable of reacting with NCO groups in a polymerization reaction. Polyfunctional amine groups which are reactive with NCO groups are preferably selected from hydroxyl groups and primary or secondary amino groups. The reaction of NCO groups with amino groups leads to the formation of urea groups. The reaction of NCO groups with OH groups leads to the formation of urethane groups. However, reaction with OH groups often requires a catalyst. The amount of polyfunctional amines that is introduced is usually in molar excess with respect to the stoichiometric amount required to convert the free isocyanate groups.

The polyfunctional amine is preferably selected from diamines, triamines, tetramines and higher order polyfunctional amines, amino alcohols, melamines, ureas, hydrazines, polymeric polyamines and mixtures thereof.

Suitable diamines are, for example, 1,2-ethylenediamine, 1,3-propylenediamine, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,3-diamino-1-methylpropane, 1,4- diaminocyclohexane, piperazine or mixtures thereof.

Suitable amino alcohols are, for example, 2-aminoethanol, 2-(N-methylamino)ethanol, 3-aminopropanol, 4-aminobutanol, 1-ethylaminobutan-2-ol, 2-amino-2-methyl-1-propanol, 4-methyl -4-aminopentan-2-ol or mixtures thereof.

Suitable polymeric polyamines are in principle linear or branched polymers which contain at least two primary or secondary amino groups. Additionally, these polymers may contain tertiary amino groups in the polymer chain.

The polymeric polyamine is preferably selected from polyalkyleneamines, polyvinylamines, polyesteramines and mixtures thereof. More preferably, the polymeric polyamine is selected from polyalkyleneimines, in particular polyethyleneimines.

Preference is given to polymeric polyamines having a weight average molecular weight of at least 300 g/mol. More preferred are polymeric polyamines having a weight average molecular weight of 500 to 2,000,000 g/mol, in particular 700 to 1,000,000 g/mol, even more preferably 800 to 500,000 g/mol.

In a preferred embodiment, the polyfunctional amine contains at least one polyethyleneimine or consists of at least one polyethyleneimine.

Polyethyleneimines can be short chain polyethyleneimines of general formula H ₂ N(CH ₂ CH ₂ NH) _n H, wherein n is an integer >1 (n=2: diethylenetriamine, n=3: triethylenetetramine, n=4: tetraethylenepentamine). They are sometimes called polyethyleneamines or polyalkylenepolyamines. Polyethyleneimines can also be long chain polyethyleneimines.

The methods of the present invention preferably use polyethyleneimines with a molecular weight of at least 500 g/mol, preferably from 600 to 30000 or from 650 to 25000 g/mol and in particular from 700 to 10000 g/mol or from 850 to 5000 g /mol.

The polyfunctional amine may be a polyethyleneimine containing the following repeating units:

where

x is from 8 to 1500, preferably from 10 to 1000,

y is 0 to 10, preferably 0 to 5, especially 0,

z is 2+y.

Good results can be achieved with these polyethyleneimines, in particular with regard to leakage in extractive media.

Preferred polyethyleneimines are linear polyethyleneimines wherein x is 8 to 1500, y is 0 and z is 2

Preferred commercially available polyethyleneimines are sold by BASF SE under the trademark Lupasol®, in particular LupasolTM G100.

Preferably, polyethyleneimine and isocyanate compounds are used in a weight ratio of 1:1 to 1:5, in particular 1:2 to 1:3, or in a weight ratio of dry matter of 1:1 to 1:10, in particular 1:4 to 1:6. These weight ratios provide resins with the highest encapsulation efficiency and are therefore the most suitable for encapsulation.

The formation of shells around the droplets can be carried out by heating. This can be achieved at a temperature of at least 50°C, preferably at least 60°C, more preferably from 65°C to 90°C, to ensure that the reaction proceeds sufficiently quickly. It may be preferable to raise the temperature continuously or in steps (eg 5° C. in each case) until the reaction is substantially complete. The dispersion can then be cooled to room temperature.

To form shells around the droplets, the pH of the aqueous phase can be set to 4 to 8, preferably 5 to 7, eg about 6. The pH can be adjusted using an inorganic base, eg sodium hydroxide solution or carbonate buffer salts.

The reaction time generally depends on the nature of the reactive wall-forming materials, the amount of said materials used, and the temperature used. The reaction time ranges from several minutes to several hours. Typically, the formation of microcapsules is carried out over a period of from about 60 minutes to 6 hours, or up to 8 hours at the temperatures defined above.

Microcapsules obtained according to the method of the present invention can be coated with a coating material.

In a specific embodiment of the present invention, the coating material can be covalently grafted onto the shell of the microcapsule. The grafting step can be performed by treating the core-shell microcapsules with a coating material that contains functional groups that are capable of reacting with the functional groups present in the shells of the core-shell microcapsules, such as, for example, any residual unreacted acrylate functional groups of the polyfunctional constituents. shell of an acre of regular monomers.

As stated above in this document, the coating material may be a preformed polymer that can be covalently grafted onto the shell of the microcapsule. Alternatively, it may be a polymer which is formed in-situ by polymerization of suitable monomers during the coating process.

Preferably, the coating materials are formed from polymerizable monomers which, upon activation, can react with residual acrylate functionality present in the microcapsule shell. Particular polymerizable monomers suitable for forming coating materials include, but are not limited to, acrylates or methacrylates such as methyl methacrylate (MMA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA), and olefin group-containing quaternized compounds such as diallyldimethylammonium chloride ( DADMAC).

Accordingly, in a particular embodiment of the present invention, there is provided a process for forming a microcapsule and an encapsulated composition containing it, comprising the steps of:

- formation of a suspension of microcapsules according to the method described above in this document,

- adding a polymerizable monomer to the suspension and performing both polymerization of the monomer and its reaction with residual acrylate functional groups contained in the shells of the microcapsules to form a coating material covalently bonded to the shells of the microcapsules of the core-shell type.

The formation of the coating material and its grafting to the core-shell microcapsules is preferably carried out at an elevated temperature, for example from about 50°C to about 100°C, preferably from about 55 to about 95°C, more preferably from about 60 to about 90°C. C, for example, 80±5°C. The reaction can be carried out over a period of time from about 1 hour to about 10 hours, preferably from about 2 hours to about 8 hours, more preferably from about 3 to about 6 hours. The reaction can be initiated with a free radical initiator such as 2,2'-azobisisobutyronitrile (AIBN), potassium persulfate, benzoyl peroxide, or any other suitable initiator for this purpose.

The coating material may be a cationic polymer, in particular in cases where the shell of at least one core-shell type microcapsule is a polyurea shell.

In the above process for preparing polyurea microcapsules, the cationic polymer may be added during the formation of the shell, whereby the polymer may take part in the formation of the shell and, for example, may be physically retained in the shell or be covalently associated with it. The cationic polymer can also be added after the formation of the shell, whereby the polymer does not take part in the formation of the shell, but is possibly deposited on the surface of the shell.

The cationic groups in a cationic polymer may be independent of pH. The cationic groups in the cationic polymer may be quaternary ammonium groups.

The cationic polymer can be derived from at least one monomer bearing a quaternary ammonium functional group. In particular, the cationic monomer may be selected from the group consisting of dimethylaminoethyl acrylate quat (ADAME), dimethylaminoethyl methacrylate quat (MADAME), dimethyldiallylammonium chloride (DADMAC), acrylamidepropyltrimethylammonium chloride (ARTAC) and methacrylamidopropyltrimethylammonium chloride (MARTAC).

The cationic polymer can also be prepared from a non-ionic monomer selected from the group consisting of water-soluble vinyl monomers, more specifically acrylamide, methacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, N-vinylformamide, N-vinylacetamide, N -vinylpyridine and/or N-vinylpyrrolidone.

Alternatively, the coating material may be an ampholytic polymer. In the context of the present invention "ampholytic polymer" should be understood as a polymer containing both cationic and anionic groups, or containing the corresponding ionic groups. The ampholytic polymer may contain more cationic groups than anionic groups or groups that can form anions, and as such may have a net positive charge.

Ampholytic polymer may contain from 1 to 99 mol. % cationic groups and from 1 to 99 mol. % anionic groups or groups that can form an anion. In a preferred embodiment of the present invention, the ampholytic polymer contains from 2 to 99 mol. %, preferably from 30 to 95 mol. % and more preferably from 60 to 90 mol. % cationic groups and from 1 to 98 mol. %, preferably from 5 to 70 mol. % and more preferably from 10 to 40 mol. % anionic groups or groups that can form an anion.

The ampholytic polymer may be a copolymer derived from a cationic monomer or a monomer which can form cations, in particular containing at least one quaternary ammonium group, an anionic monomer or a monomer which can form anions, in particular based on acrylic acid, methacrylic acid or derivatives thereof, and possibly a non-ionic monomer. Such polymers provide an optimal combination of shell compatibility, good dispersion efficiency, good flow characteristics, and excellent affinity with the various bases mentioned above.

The ampholytic polymer can be prepared from a monomer selected from the group consisting of acrylic-based monomers including acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and strong acid-based monomers, e.g. sulfonic or phosphonic acid such as 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, allylphosphonic acid, styrenesulfonic acid. The acrylic-based monomer may also be in the form of any water-soluble salts of these monomers, wherein the salt is an alkali metal, alkaline earth metal or ammonium salt. The most preferred acrylic-based monomer is acrylic acid, methacrylic acid, or a water-soluble salt thereof.

In a more specific embodiment, the ampholytic copolymer is a copolymer of acrylic acid and dimethyldiallylammonium chloride (DADMAC).

The ampholytic polymer can be obtained using polymerization techniques that are well known to those skilled in the art. These known polymerization technologies include solution polymerization, gel polymerization, precipitation polymerization, inverse emulsion polymerization, aqueous emulsion polymerization, suspension polymerization, and micellar polymerization.

The ampholytic polymer can be used in the encapsulated perfume composition of the present invention in an amount of 1 to 20 wt. %, preferably from 2 to 10 wt. %, based on the weight of the composition.

The encapsulated perfume composition formed according to the present invention consists of a suspension of core-shell capsules suspended in an aqueous suspending medium, which may contain core-shell capsules in an amount of 20 to 50 wt. % by weight of the suspension. Moreover, core-shell capsules may consist of from about 80 to 95 wt. % encapsulated oil and from about 5 to 20 wt. % shell.

The suspension can be used directly as a perfume composition in any form of consumer products. Alternatively, the suspension can be dehydrated by any of the known drying techniques, such as spray drying, to create an encapsulated perfume composition in dry powder form.

Fragrances for use in the compositions of the present invention can be selected from natural products such as essential oils, absolutes, resinoids, resins, concretes, and synthetic perfume components such as hydrocarbons, alcohols, aldehydes, ketones, ethers, acids, acetals, ketals. and nitriles, including saturated and unsaturated compounds, aliphatic, carbocyclic and heterocyclic compounds, or precursors of any of the above compounds.

Examples of preferred perfume ingredients are any of those selected from ADOXAL (2,6,10-trimethylundec-9-enal), AGRUMEX (2-(tert-butyl)cyclohexyl acetate), ALDEHYDE C 10 DECYLIC (decanal), ALDEHYDE C 11 MOA (2-methyldecanal), ALDEHYDE C 11 UNDECYLENIC (undec-10-enal), ALDEHYDE C 110 UNDECYLIC (undecenal), ALDEHYDE C 12 LAURIC (dodecanal), ALDEHYDE C 12 MNA PURE (2-methylundecenal), ALDEHYDE ISO C 11 ( (E)-unlez-9-enal), ALDEHYDE MANDARINE 10%/TEC ((E)-dodec-2-enal), ALLYL AMYL GLYCOLATE (allyl-2-(isopentyloxy) acetate), ALLYL CYCLOHEXYL PROPIONATE (allyl-3 -cyclohexylpropanoate), ALLYL OENANTHATE (allylheptanoate), AMBER CORE (1-((2-(tert-butyl)cyclohexyl)oxy)butan-2-ol), AMBERMAX (1,3,4,5,6,7-hexahydro-. beta.,1,1,5,5-pentamethyl-2H-2,4a-methanonaphthalene-8-ethanol), AMYL SALICYLATE (pentyl-2-hydroxybenzoate), APHERMATE (1-(3,3-dimethylcyclohexyl)ethyl format), BELAMBRE ((1R,2S,4R)-2'-isopropyl-1,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,4'-[1,3]dioxane]), BIGARYL (8-( in torbutyl)-5,6,7,8-tetrahydroquinoline), BOISAMBRENE FORTE ((ethoxymethoxy)cyclododecane), BOISIRIS ((1S,2R,5R)-2-ethoxy-2,6,6-trimethyl-9-methylenebicyclo[3.3 .1]nonane), BORNYL ACETATE ((2S,4S)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl acetate), BUTYL BUTYRO LACTATE (1-butoxy-1-oxopropan-2-ylbutyrate) , BUTYL CYCLOHEXYL ACETATE PARA (4-(tert-butyl)cyclohexyl acetate), CARYOPHYLLENE ((Z)-4,11,11-trimethyl-8-methylenebicyclo[7.2.0]undec-4-ene), CASHMERAN (1,1,2 ,3,3-pentamethyl-2,3,6,7-tetrahydro-1H-inden-4(5H)-one), CASSYRANE (5-tert-butyl-2-methyl-5-propyl-2H-furan), CITRAL ( (E)-3,7-dimethylocta-2,6-dienal), CITRAL LEMAROME N ((E)-3,7-dimethylocta-2,6-dienal), CITRATHAL R ((Z)-1,1-diethoxy -3,7-dimethylocta-2,6-diene), CITRONELLAL (3,7-dimethylocta-6-enal), CITRONELLOL (3,7-dimethylocta-6-en-1-ol), CITRONELLYL ACETATE (3.7 -dimethyloct-6-en-1-yl acetate), CITRONELLYL FORMATE (3,7-dimethyloct-6-en-1-ylformate), CITRONELLYL NITRILE (3,7-dimethyloct-6-ennitrile), CITRONELLYL PROPIONATE (3.7 -dimethyloct-6-en-1-ylpropionate), C LONAL (dodecanitrile), CORANOL (4-cyclohexyl-2-methylbutan-2-ol), COSMONE ((Z)-3-methylcyclotetradec-5-enone), CYCLAMEN ALDEHYDE (3-(4-isopropylphenyl)-2-methylpropanal) , CYCLOGALBANATE (allyl-2-(cyclohexyloxy)acetate), CYCLOHEXYL SALICYLATE (cyclohexyl-2-hydroxybenzoate), CYCLOMYRAL (8,8-dimethyl-1,2,3,4,5,6,7,8-octahydronaphthalene-2 -carbaldehyde), DAMASCENONE ((E)-1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)but-2-en-1-one), DAMASCONE ALPHA ((E)-1 -(2,6,6-trimethylcyclohex-2-en-1-yl)but-2-en-1-one), DAMASCONE DELTA ((E)-1-(2,6,6-trimethylcyclohex-3-ene -1-yl)but-2-en-1-one), DECENAL-4-TRANS ((E)-dec-4-enal), DELPHONE (2-pentylcyclopentanone), DIHYDRO ANETHOLE (1-(1-(3 ,3-dimethylcyclohexyl)ethyl)-3-ethyl ester of propanedioic acid), DIHYDRO JASMONE (3-methyl-2-pentylcyclopent-2-enone), DIMETHYL BENZYL CARBINOL (2-methyl-1-phenylpropan-2-ol), DIMETHYL BENZYL CARBINYL ACETATE (2-methyl-1-phenylpropan-2-yl acetate), DIMETHYL BENZYL CARBINYL BUTYRATE (2-methyl-1-phenylpropan-2-ylbutyrate), DIMETHYL OC TENONE (4,7-dimethyloct-6-en-3-one), DIMETOL (2,6-dimethylheptan-2-ol), DIPENTENE (1-methyl-4-(prop-1-en-2-yl)cyclohex -1-ene), DUPICAL ((E)-4-((3aS,7aS)-hexahydro-1H-4,7-methanoinden-5(6H)-ylidene)butanal), EBANOL ((E)-3-methyl -5-(2,2,3-trimethylcyclopent-3-en-1-yl)pent-4-en-2-ol), ETHYL CAPROATE (ethylhexanoate), ETHYL CAPRYLATE (ethyloctanoate), ETHYL LINALOOL ((E)- 3,7-dimethylnona-1,6-dien-3-ol), ETHYL LINALYL ACETATE ((Z)-3,7-dimethylnona-1,6-dien-3-ylacetate), ETHYL OENANTHATE (ethylheptanoate), ETHYL SAFRANATE (ethyl 2,6,6-trimethylcyclohexa-1,3-diene-1-carboxylate), EUCALYPTOL ((1s,4s)-1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane), FENCHYL ACETATE ((2S)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl acetate), FENCHYL ALCOHOL ((1S,2R,4R)-1,3,3-trimethylbicyclo[2.2.1]heptan- 2-ol), FIXOLIDE (1-(3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)ethanone), FLORALOZONE (3-(4-ethylphenyl) -2,2-dimethylpropanal), FLORHYDRAL (3-(3-isopropylphenyl)butanal), FLOROCYCLENE ((3aR,6S,7aS)-3a,4,5,6,7,7a-hexahydro-1H-4,7- me tanoinden-6-ylpropionate), FLOROPAL (2,4,6-trimethyl-4-phenyl-1,3-dioxane), FRESKOMENTHE (2-(sec-butyl)cyclohexanone), FRUITATE ((3aS,4S,7R,7aS)- ethyloctahydro-1H-4,7-methanoinden-3a-carboxylate), FRUTONILE (2-methyldecannitrile), GALBANONE PURE (1-(3,3-dimethylcyclohex-1-en-1-yl)pent-4-en-1- he), GARDOCYCLENE ((3aR,6S,7aS)-3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-ylisobutyrate), GERANIOL ((E)-3,7- dimethylocta-2,6-dien-1-ol), GERANYL ACETATE SYNTHETIC ((E)-3,7-dimethylocta-2,6-dien-1-yl acetate), GERANYL ISOBUTYRATE ((E)-3,7-dimethylocta -2,6-dien-1-ylisobutyrate), GIVESCONE (ethyl-2-ethyl-6,6-dimethylcyclohex-2-enecarboxylate), HABANOLIDE ((E)-oxacyclohexadec-12-en-2-one), HEDIONE ( methyl 3-oxo-2-pentylcyclopentaneacetate), HERBANATE ((2S)-ethyl-3-isopropylbicyclo[2.2.1]hept-5-en-2-carboxylate), HEXENYL-3-CIS BUTYRATE ((Z)-hex -3-en-1-ylbutyrate), HEXYL CINNAMIC ALDEHYDE ((E)-2-benzylidenodectanal), HEXYL ISOBUTYRATE (hexylisobutyrate), HEXYL SALICYLATE (hexyl-2-hydroxybenzoate), INDOFLOR (4,4a,5,9b-t tetrahydroindeno[1,2-d][1,3]dioxin), IONONE BETA ((E)-4-(2,6,6-trimethylcyclohex-1-en-1-yl)but-3-en-2- he), IRISONE ALPHA ((E)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one), IRONE ALPHA ((E)-4-( 2,5,6,6-tetramethylcyclohex-2-en-1-yl)but-3-en-2-one), ISO E SUPER (1-(2,3,8,8-tetramethyl-1,2, 3,4,5,6,7,8-octahydronaphthalen-2-yl)ethanone), ISOCYCLOCITRAL (2,4,6-trimethylcyclohex-3-enecarbaldehyde), ISONONYL ACETATE (3,5,5-trimethylhexyl acetate), ISOPROPYL METHYL -2-BUTYRATE (isopropyl-2-methylbutanoate), ISORALDEINE 70 ((E)-3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2- he), JASMACYCLENE ((3aR,6S,7aS)-3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-yl acetate), JASMONE CIS ((Z)-3-methyl -2-(pent-2-en-1-yl)cyclopent-2-enone), KARANAL (5-(sec-butyl)-2-(2,4-dimethylcyclohex-3-en-1-yl)-5-methyl -1,3-dioxane), KOAVONE ((Z)-3,4,5,6,6-pentamethylhept-3-en-2-one), LEAF ACETAL ((Z)-1-(1-ethoxyethoxy)hex -3-ene), LEMONILE ((2E,6Z)-3,7-dimethylnona-2,6-diennitrile), LIFFAROME GIV ((Z)-hex-3-en-1-ylmethyl carbonate ), LILIAL (3-(4-(tert-butylphenyl)phenyl)-2-methylpropanal), LINALOOL (3,7-dimethylocta-1,6-dien-3-ol), LINALYL ACETATE (3,7-dimethylocta-1, 6-dien-3-yl acetate), MAHONIAL ((4E)-9-hydroxy-5,9-dimethyl-4-decenal), MALTYL ISOBUTYRATE (2-methyl-4-oxo-4H-pyran-3-ylisobutyrate), MANZANATE (ethyl-2-methylpentanoate), MELONAL (2,6-dimethyhept-5-enal), MENTHOL (2-isopropyl-5-methylcyclohexanol), MENTHONE (2-isopropyl-5-methylcyclohexanone), METHYL CEDRYL KETONE (1- ((1S,8aS)-1,4,4,6-tetramethyl-2,3,3a,4,5,8-hexahydro-1H-5,8a-methanoazulen-7-yl)ethanone), METHYL NONYL KETONE EXTRA (undecan-2-one), METHYL OCTYNE CARBONATE (methylnon-2-inoate), METHYL PAMPLEMOUSSE (6,6-dimethoxy-2,5,5-trimethylhex-2-ene), MYRALDENE (4-(4-methylpent- 3-en-1-yl)cyclohex-3-enecarbaldehyde), NECTARYL (2-(2-(4-methylcyclohex-3-en-1-yl)propyl)cyclopentanone), NEOBERGAMATE FORTE (2-methyl-6-methyleneoct -7-en-2-ylacetate), NEOFOLIONE ((E)-methylnon-2-enoate), NEROLIDYLE ((Z)-3,7,11-trimethyldodeca-1,6,10-trien-3-yl acetate), NERYL ACETATE HC ((Z)-3,7- dimethylocta-2,6-dien-1-yl acetate), NONADYL (6,8-dimethylnonan-2-ol), NONENAL-6-CIS ((Z)-non-6-enal), NYMPHEAL (3-(4- isobutyl-2-methylphenyl)propanal), ORIVONE (4-(tert-pentyl)cyclohexanone), PARADISAMIDE (2-ethyl-N-methyl-N-(m-tolyl)butanamide), PELARGENE (2-methyl-4-methylene-6 -phenyltetrahydro-2H-pyran), PEONILE (2-cyclohexylidene-2-phenylacetonitrile), PETALIA (2-cyclohexylidene-2-(o-tolyl)acetonitrile), PIVAROSE (2,2-dimethyl-2-phenylethylpropanoate), PRECYCLEMONE B (1-methyl-4-(4-methylpent-3-en-1-yl)cyclohex-3-enecarbaldehyde), PYRALONE (6-(sec-butyl)quinoline), RADJANOL SUPER ((E)-2-ethyl-4- (2,2,3-trimethylcyclopent-3-en-1-yl)but-2-en-1-ol), RASPBERRY KETONE (N112) (4-(4-hydroxyphenyl)butan-2-one), RHUBAFURANE ( 2,2,5-trimethyl-5-pentylcyclopentanone), ROSACETOL (2,2,2-trichloro-l-phenylethyl acetate), ROSALVA (dec-9-en-1-ol), ROSYFOLIA ((1-methyl-2- (5-methylhex-4-en-2-yl)cyclopropyl)methanol), ROSYRANE SUPER (4-methylene-2-phenyltetrahydro-2H-pyran), SERENOLIDE (2-(1-(3,3-dimethylcyclohexyl)ethoxy) -2-methylpropyl qi clopropanecarboxylate), SILVIAL (3-(4-isobutylphenyl)-2-methylpropanal), SPIROGALBANONE (1-(spiro[4.5]dec-6-en-7-yl)pent-4-en-1-one), STEMONE ( (E)-5-methylheptan-3-onoxime), SUPER MUGUET ((E)-6-ethyl-3-methyloct-6-en-1-ol), SYLKOLIDE ((E)-2-((3.5 -dimethylhex-3-en-2-yl)oxy)-2-methylpropyl cyclopropanecarboxylate), TERPINENE GAMMA (1-methyl-4-propan-2-ylcyclohexa-1,4-diene), TERPINOLENE (1-methyl-4- (propan-2-ylidene)cyclohex-1-ene), TERPINYL ACETATE (2-(4-methylcyclohex-3-en-1-yl)propan-2-yl acetate), TETRAHYDRO LFNALOOL (3,7-dimethyloctan-3- ol), TETRAHYDRO MYRCENOL (2,6-dimethyloctan-2-ol), THIBETOLIDE (oxacyclohexadecan-2-one), TRIDECENE-2-NITRILE ((E)-tridec-2-ennitrile), UNDECAVERTOL ((E)-4 -methyldec-3-en-5-ol), VELOUTONE (2,2,5-trimethyl-5-pentylcyclopentanone), VIRIDINE ((2,2-dimethoxyethyl)benzene), ZINARINE (2-(2,4-dimethylcyclohexyl) pyridine) and mixtures thereof.

In another particular embodiment, in addition to or instead of perfume ingredients, a cosmetic active ingredient can be encapsulated in core-shell microcapsules. Preferably the cosmetic actives have a calculated partition coefficient (clogP) octanol/water of 1.5 or more, more preferably 3 or more. Preferably the clogP of the cosmetic active is from about 2 to about 7.

Particularly suitable cosmetic actives can be selected from the group consisting of skin emollients, smoothing agents, moisturizers, soothing and relaxing agents, color cosmetics, deodorants, anti-aging agents, drying agents, corrective agents, smoothing agents, preservatives, antioxidants, antimicrobial or bacteriostatic agents, cleansers, moisturizers, texturing agents, hair care products, bleaching agents, texturizing agents, emollients, anti-dandruff agents and exfoliating agents.

Particularly suitable cosmetic actives include, but are not limited to, hydrophobic polymers such as alkyldimethylsiloxanes, polymethylsilsesquioxanes, polyethylene, polyisobutylene, styrene-ethylene-styrene and styrene-butylene-styrene block copolymers, and the like; mineral oils such as hydrogenated isoparaffins, silicone oils, and the like; vegetable oils such as argan oil, jojoba oil, aloe vera oil and the like; fatty acids and fatty alcohols and their esters, glycolipids, phospholipids, sphingolipids such as ceramides, sterols and steroids; terpenes, sesquiterpenes, triterpenes and their derivatives; essential oils such as arnica oil, artemisia oil, cinchona oil, birch bud oil, calendula oil, cinnamon oil, echinacea oil, eucalyptus oil, ginseng oil, jujube oil, sunflower oil, jasmine oil, lavender oil, lotus seed oil , perilla oil, rosemary oil, sandalwood oil, tea tree oil, thyme oil, valerian oil, wormwood oil, ylang ylang oil, yucca oil, etc.

In one embodiment, the cosmetic active may be selected from the group consisting of sandalwood oil such as Fusanus spicatus seed oil, panthenyl triacetate (CAS no.: 94089-18-6), tocopheryl acetate (CAS no.: 7695-91-2), tocopherol ( CAS No.: 1406-66-2/10191-41-0/2074-53-5/59-02-9/148-03-8/119-13-1/54-28-4), Naringinin (CAS No. : 480-41-1), ethyl linoleate, farnesyl acetate, farnesol, citronellyl methyl crotonate (CAS no.: 20770-40-5), Ceramide-2 (1-stearoyl-C18-sphingosine, CAS no.: 100403-19-8) and mixtures thereof .

The encapsulated compositions of the present invention can be used as a delivery system to deliver active ingredients such as fragrances for use in any form of consumer product. The term "consumer products" refers in particular to home care products, fabric care products, or personal care products such as body and hair care products.

The encapsulated compositions of the present invention are particularly useful as a means of delivering fragrances to consumer products where this is required to provide optimal perfume benefits in that the microcapsules adhere well to the substrate to which they are applied. Such consumer products include shampoos and hair conditioners, as well as fabric treatment products such as detergents and laundry conditioners.

The following are a number of examples that serve to further illustrate the invention.

Example 1 Preparation of formaldehyde-free microcapsules from melamine and acrylate

In the first example (Example 1.1), formaldehyde-free microcapsules were prepared from melamine and pentaerythritoltetraacrylate by performing the following steps:

1) obtaining a core composition containing 3-aminopropyltriethoxysilane by mixing 0.5 g of 3-aminopropyltriethoxysilane and 40 g of a fragrance composition,

2) emulsifying the core composition obtained in step (1) in a mixture of 35 g of water and 15 g of an aqueous solution of ZeMac E400 at 10 wt. % (= 1.5 g solid ZeMac E400), using a crossbar stirrer with an inclined bar, operating at a stirring speed of 600 rpm, at a temperature of 35±2°C,

3) adjusting the pH to 4.4±0.2 with 0.7 g of a 20% solution of NH ₃ in water and maintaining the system at a temperature of 35±2°C for 1 hour, while maintaining stirring, as in stage (2 ),

4) adding 1.1 g of melamine in powder form and 2.9 g of pentaerythritoltetraacrylate (PETA) and then raising the pH to 8.7±0.2 by adding 3.8±1 g of a 20% solution of NH ₃ in water, while maintaining agitation as in step (2),

5) heating the mixture obtained in step (2) to 80±5°C for 1 hour and maintaining this temperature and stirring for 3 hours to obtain a suspension of microcapsules,

6) cooling the suspension to room temperature for 120 minutes.

The solids content of the suspension was measured using a thermobalance operating at 120°C. The solids content, expressed as the weight percentage of the initial slurry applied to the balance, was determined at the moment when the rate of weight change caused by drying fell below 0.1%/min. The solids content in example 1.1 was 45 wt. %, based on the total weight of the suspension. The encapsulation yield, expressed as the ratio of encapsulated fragrance composition to the nominal amount of fragrance composition, was 100%. The volume-average diameter of the capsules was Dv(50)=19 μm.

In another alternative example (example 1.2), the method was carried out as in example 1.1, but in the additional step (7) 1 g of methyl methacrylate, 3 g of a 4% solution of potassium peroxodisulfate in water and 0.2 g of azoisobutyronitrile (AIBN) were added to the suspension obtained on step (5), and methyl methacrylate was left to polymerize by free radical polymerization for one hour at 80±5°C with constant stirring. The solids content at 120° C. was 44.7 wt. %, based on the total weight of the suspension. The encapsulation yield was 98% and the volume average capsule diameter was Dv(50)=16 μm.

In another alternative example (example 1.3), the method was carried out as in example 1.1, but in step (2) 0.5 g of a copolymer of styrene and maleic anhydride with cumene end groups (PSMA) and 10 g of ZeMac E400 solution were used. The content of solids at 120°C was 45 wt. %, based on the total weight of the suspension, and the volume average diameter of the capsules was Dv(50)=12 μm.

In the comparative example (Example 1.4), no 3-aminopropyltriethoxysilane was added and ZeMac E400 was used as the traditional emulsifier. In this case, no capsules were received.

Example 2 Preparation of microcapsules from an aminoplast

Amino microcapsules were obtained by performing the following steps:

1) obtaining a core composition containing 3-aminopropyltriethoxysilane by mixing 0.5 g of 3-aminopropyltriethoxysilane and 40 g of a fragrance composition,

2) emulsifying the core composition obtained in step (1) in a mixture of 35 g of water and 15 g of an aqueous solution of ZeMac E400 at 10 wt. % (= 1.5 g solid ZeMac E400), using a crossbar stirrer with an inclined bar, operating at a stirring speed of 600 rpm, at a temperature of 35±2°C,

3) adjusting the pH to 4.4±0.2 with 0.7 g of a 20% solution of NH ₃ in water and maintaining the system at a temperature of 35±2°C for 1 hour, while maintaining stirring, as in stage (2 ),

4) adding 1.65 g of Luracoll SD melamine precondensate and 1.04 g of urea and maintaining the temperature at 35±2°C for another hour with stirring,

5) raising the temperature to 88±5°C for 1 hour and then maintaining this temperature and stirring conditions for another hour to obtain a suspension of uncoated microcapsules,

6) adding 1.65 g of Luracoll SD and 3.8 g of a 30% solution of ethylene urea in water, maintaining the temperature at 88°C for another 10 minutes and then cooling the suspension to a temperature below 40°C and bringing the pH of the suspension to 7±0 .5 using 2.16 g 10 wt. % NaOH solution in water to obtain the amino resin microcapsule suspension of the present invention (Example 2.1).

The slurry obtained in Example 2.1 was characterized as described in Example 1. The solids content of the slurry formed in Example 2.1 was 48 wt. %. The encapsulation yield, expressed as the ratio of encapsulated fragrance composition to the nominal amount of fragrance composition, was 100%. The volume-average diameter of the capsules was Dv(50)=13 μm.

In the comparative example (example 2.2), standard amino microcapsules were prepared according to WO 2017/001672, example 1.

Example 3. Obtaining microcapsules from a copolymer of acrylate and divinylbenzene

Acrylate-divinylbenzene copolymer microcapsules were obtained by performing the following steps:

1) obtaining a core composition containing 3-aminopropyltriethoxysilane by mixing 0.56 g of 3-aminopropyltriethoxysilane and 40 g of a fragrance composition,

2) emulsifying the core composition obtained in step (1) in a mixture of 35 g of water and 15 g of an aqueous solution of ZeMac E400 at 10 wt. % (= 1.5 g solid ZeMac E400), using a crossbar stirrer with an inclined bar, operating at a stirring speed of 600 rpm, at a temperature of 35 ± 2 ° C, for an hour, while maintaining agitation,

3) bringing the pH to 4.4±0.2 with 0.7 g of a 20% solution of NH ₃ in water and maintaining the system at a temperature of 35±2°C for 1 hour,

4) adding 1.72 g of divinylbenzene, 0.98 g of methyl methacrylate and 0.48 g of azoisobutyronitrile (AIBN) to the suspension, raising the temperature to 65°±5°C and maintaining this temperature for 3 hours with stirring,

5) adding 5.48 g of 4 wt. % solution of potassium persulfate in water and setting the temperature to 85 ° C for another two hours with stirring,

6) cooling the suspension to a temperature below 40°C and bringing the pH of the suspension to 7±0.5 with 10 wt. % NaOH solution in water to obtain a microcapsule suspension of the acrylate-divinylbenzene copolymer of the present invention (Example 3.1).

The slurry obtained in Example 3.1 was characterized as described in Example 1. The solids content of the slurry formed in Example 3.1 was 42 wt. %. The encapsulation yield, expressed as the ratio of encapsulated fragrance composition to the nominal amount of fragrance composition, was 97%. The volume-average diameter of the capsules was Dv(50)=10 μm.

In the comparative example (example 3.2), the method of example 3.1 was repeated, but 3-aminopropyltriethoxysilane was not used. In this case, no capsules were formed.

Example 4 Preparation of microcapsules based on polyurea

Microcapsules based on polyurea were obtained by performing the following steps:

1) obtaining a core composition containing 3-aminopropyltriethoxysilane by mixing 2.0 g of 3-aminopropyltriethoxysilane and 300 g of a fragrance composition,

2) emulsifying the core composition obtained in step (1) in 556 g of an aqueous solution of ZeMac E400 at 3 wt. % (= 556 g solid ZeMac E400), using a mechanical stirrer operating at 900 rpm, at a temperature of 35±2°C,

3) bringing the pH to 6.0 by adding 10 wt. % NaOH solution in water and maintaining the system under stirring, as in stage (2), at a temperature of 35±2°C for 1 hour,

4) adding 2 g water-dispersible hexamethylene diisocyanate isocyanate (Bayhydur® XP2547, Covestro) and 22 g 4,4-dicyclohexylmethanediyl diisocyanate (Desmodur® W1, Covestro) to form an emulsion and keep the system under agitation as in steps (2) and (3) at 35±2°C for 30 minutes,

5) adding 8 g of polyethyleneimine solution (Lupasol® G100, BASF) in one step and gradually heating the reaction mixture to 70°C for 2 hours,

6) adding 12.5 g of 40 wt. % aqueous solution of a copolymer of acrylic acid and diallyldimethylammonium chloride (Merquat 281, Lubrizol) and additional heating of the reaction mixture to 85°C for 2 hours,

7) adding 10 g ammonia solution and 3 g hydroxyethyl cellulose (Natrosol™ 250HX, Ashland) and cooling the mixture to room temperature,

8) bringing the final pH of the suspension to 4.0 ± 0.2 with a solution of citric acid (example 4.1).

The volume average capsule size distribution obtained from light scattering measurements using a Malvern 2000S instrument was Dv(50)=18 µm and Dv(90)=27 µm. The electrokinetic potential was +25 mV.

Example 5 Comparison of Particle Size and Particle Size Distribution

The solids content and particle size distributions for the capsules obtained in examples 1-4, measured by light scattering using Mie theory, are presented in the table below. The particle size distribution is given using its Dv(10), Dv(50) and Dv(90) values, where the Dv(10) value is the diameter at which 10% of the mass of the sample is contained in capsules smaller than this value, the Dv(50 ) is the median capsule diameter and is taken as the volume average capsule size, and the Dv(90) value is the diameter at which 90% of the mass of the sample is contained in capsules smaller than this value. Spread is defined as (Dv(90)-Dv(10))/Dv(50) and is taken as a rough measure of polydispersity.

The table also shows the size distribution in the emulsion obtained by performing only steps (1)-(3) of example 1 with 3-aminopropyltriethoxysilane (example 1.1) and without 3-aminopropyltriethoxysilane (example 1.4).

As is clear from the spread values, the microcapsules obtained by carrying out the methods of the present invention, ie using a novel emulsifier which is synthesized in situ by reacting 3-aminopropyltriethoxysilane with ZeMac E400 or PSMA, are remarkably monodisperse. Chemically similar microcapsules can be obtained with ZeMac E400 as a conventional emulsifier (Example 2.2), these latter microcapsules being larger and significantly more polydisperse. However, as shown in Examples 1 and 3, alternative chemistries such as melamine-acrylate chemistry or divinylbenzene-methyl methacrylate copolymer chemistry are not viable if a new emulsifier is replaced with a traditional emulsifier.

This example and examples 1-3 confirm the superiority of the modified Zemac and PSMA emulsifiers over the traditional, unmodified ZeMac E400 emulsifier.

Example 6 Comparison of Olfactory Characteristics of New and Conventional Amino Microcapsules

The microcapsules of the present invention and conventional microcapsules were evaluated in a proprietary, fragrance-free laundry detergent base. 75 g of this base is used in a side loading washing machine (capacity 20 l, loaded with 1 kg of terry towels until filled with water), the washing cycle is carried out at a temperature of 40°C, followed by spinning in a centrifuge.

The olfactory assessment before rubbing was performed on wet laundry immediately after the washing machine and after 4 hours. For this evaluation, the terry towels were handled with care to minimize the risk of mechanical breakage of the capsules. The post-rubbing olfactory evaluation was performed after drying the terry towels for 24 hours at room temperature. This assessment was made by lightly rubbing one part of a terry towel against another part of the same terry towel. The olfactory characteristic (intensity) was assessed by a panel of 4 experts rated on a scale of 1 to 5 (1 = hardly noticeable, 2 = weak, 3 = medium, 4 = strong and 5 = very strong). When appropriate, qualitative comments about the perceived direction of the odor were recorded.

The results show that the amino polyurea microcapsules of the present invention provide increased odor release on wet and damp tissues compared to conventional amino polyurea microcapsules while maintaining comparable pre-rubbing and post-rubbing performance on dry tissues.

Claims (22)

1. An encapsulated perfume composition comprising at least one core-shell microcapsule suspended in a suspending medium, wherein said at least one core-shell microcapsule contains a core containing at least one perfume ingredient and a shell surrounding or over at least partially surrounding the core; the shell contains a thermosetting resin formed by the reaction of shell-forming materials selected from the group consisting of monomers, prepolymers and/or precondensates, and the encapsulated perfume composition contains a polymeric stabilizer, which is the reaction product of a polymeric surfactant and a silane containing a functional a group capable of forming covalent bonds with the shell. 2. An encapsulated perfume composition according to claim 1, wherein the polymeric stabilizer is a reaction product of an aminosilane and an ethylenically unsaturated compound-maleic anhydride copolymer. 3. An encapsulated perfume composition according to claim 2, wherein the polymeric stabilizer is a reaction product of 3-aminopropylethoxysilane and at least one compound selected from the group consisting of an ethylene-maleic anhydride copolymer and a styrene-maleic anhydride copolymer. 4. Encapsulated perfume composition according to one of paragraphs. 1-3, in which the shell is a thermosetting resin formed by polycondensation of an alkylated polyfunctional amine and an aldehyde. 5. Encapsulated perfume composition according to one of paragraphs. 1-3, in which the shell is a thermosetting resin formed by the reaction of a polyfunctional amine and a polyfunctional acrylate. 6. Encapsulated perfume composition according to one of paragraphs. 1-3, in which the shell is a thermosetting resin formed by the reaction of a polyfunctional amine and at least one isocyanate. 7. The encapsulated perfume composition of claim 5 wherein the polyfunctional amine is selected from the group consisting of ethylenediamine, bis(2-aminoethyl)amine, melamine, 3,5-diamino-1,2,4-triazole, 2,4- diamino-6-phenyl-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 1,2-phenylenediamine, 1,3-phenylenediamine or 1,4-phenylenediamine and their mixtures. 8. An encapsulated perfume composition according to claim 5 or 7, wherein the polyfunctional acrylate is selected from the group consisting of pentaerythritol tetraacrylate (PETA), pentaerythritol triacrylate (PETIA), 1,4-butanediol diacrylate (BDA-2), ethylene glycol dimethacrylate (EDGMA), trimethylol propane triacrylate (TMPTA). ), hexanediol diacrylate (HDDA), ((2,4,6-trioxocyclohexane-1,3,5-triyl)tris(oxy)(tris(ethane-2,1-diyl)triacrylate (TOSTA), tris(2-acryloyloxyethyl ) isocyanurate, 1,3,5-triacryloylhexahydro-1,3,5-triazine (TANHT) and mixtures thereof. 9. Encapsulated perfume composition according to one of paragraphs. 1-8, wherein at least one core-shell type microcapsule is at least partially coated with a functional coating material. 10. The encapsulated perfume composition of claim 9 wherein the functional coating material is covalently bonded to the shell of at least one core-shell microcapsule. 11. An encapsulated perfume composition according to claim 9 or 10, wherein the functional coating material is polymethyl methacrylate. 12. The method of obtaining an encapsulated perfume composition according to any one of paragraphs. 1-11, including stages: a) forming an oil-in-water emulsion comprising at least one drop of oil containing a perfume ingredient dispersed in an external aqueous phase in the presence of a polymeric stabilizer which is the reaction product of a polymeric surfactant and a silane containing a functional group capable of formation of covalent bonds with the shell, and b) reacting the shell-forming materials present in the oil-in-water emulsion and forming at the oil-water interface a shell of thermosetting resin surrounding or at least partially surrounding said at least one drop of oil. 13. The method of obtaining an encapsulated perfume composition according to any one of paragraphs. 1-11, including stages: a) forming an oil-in-water emulsion comprising at least one fragrance-containing oil droplet dispersed in an external aqueous phase in the presence of a polymeric stabilizer which is the reaction product of a polymeric surfactant and a silane containing a functional group capable of formation of covalent bonds with the shell, b) reacting the shell-forming materials present in the oil-in-water emulsion and forming, at the oil/water interface, a thermosetting resin shell encapsulating said at least one drop of oil, and c) possibly at least partially coating the core-shell microcapsules of the functional coating material. 14. The method according to claim 12 or 13, wherein the polymeric stabilizer is formed in-situ. 15. The method of claim 14, wherein the in-situ formation of the polymeric stabilizer is carried out by the reaction of an aminosilane and a polymeric surfactant that is a copolymer of an ethylenically unsaturated compound and maleic anhydride present in the oil-in-water emulsion. 16. The method according to claim 12 or 13, wherein the polymeric stabilizer is a reaction product of an aminosilane and an ethylenically unsaturated compound-maleic anhydride copolymer. 17. The method of claim 16 wherein the polymeric stabilizer is the reaction product of 3-aminopropyltriethoxysilane and at least one compound selected from the group consisting of ethylene-maleic anhydride copolymer and styrene-maleic anhydride copolymer.