WO2013107586A2

WO2013107586A2 - Benefit delivery particle, process for preparing said particle, compositions comprising said particles and a method for treating substrates

Info

Publication number: WO2013107586A2
Application number: PCT/EP2012/076035
Authority: WO
Inventors: Adam John Limer; Craig Warren Jones; Claire Louise Richards
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited; Conopco, Inc., D/B/A Unilever
Priority date: 2012-01-17
Filing date: 2012-12-18
Publication date: 2013-07-25
Also published as: AR089736A1; WO2013107586A3

Abstract

The invention provides a personal care composition, preferably for use on human skin and/or hair, including a core-shell benefit agent carrier particle comprising: a) a core, optionally comprising a benefit agent; b) at least one polymer shell surrounding the core, c) a deposition aid, attached to the outer shell and not removed by exposure to water, said deposition aid comprising at least one polysaccharide selected from the group consisting of poly-mannan, poly-glucan, poly-glucomannan, poly-xyloglucan, poly-galactomannan, dextran, hydroxyl-propyl cellulose, hydroxy-propyl methyl cellulose, hydroxy-ethyl methyl cellulose, hydroxy- propyl guar, hydroxy-ethyl ethyl cellulose or methyl cellulose, with the proviso that the particle is not a particle having an average diameter of less than 50 micron comprising; i) at least one shell formed by a step-growth polymerisation reaction, ii) interior to said shell, at least one region formed by chain-growth polymerisation reaction which does not involve an isocyanate, wherein the shell is polymerised prior to the core.

Description

BENEFIT DELIVERY PARTICLE, PROCESS FOR PREPARING SAID PARTICLE, COMPOSITIONS COMPRISING SAID PARTICLES AND A

METHOD FOR TREATING SUBSTRATES

Technical Field

The present invention is concerned with the delivery of particles, optionally comprising benefit agents and/or deposition aids, to substrates, with processes for the manufacture of said particles and the manufacture and use of formulations comprising the same.

Background

Many home and personal care formulations seek to deliver so-called benefit agents to substrates such as cloth, hair and skin. Encapsulation of the benefit agent in particles has been proposed as a means of enhancing delivery, which is advantageous because of the expense of some benefit agents. Delivery of particles per se can also be useful where the particles, even in the absence of specific benefit agents, confer a benefit.

These particles may comprise polymers and many different types of

polymerisation are known. In the present specification a distinction will be drawn between step-growth and chain-growth polymerisation. This is the well- established reaction mechanism distinction drawn by Paul Flory in 1953 (see Paul J. Flory, "Principles of Polymer Chemistry", Cornell University Press, 1953, p.39. ISBN 0801401348). For the purposes of the present specification a chain-growth polymer is a polymer which is formed by a reaction in which monomers bond together via

rearrangement (for example, of unsaturated and typically vinyllic bonds, or by a ring-opening reaction) without the loss of any atom or molecule. Chain-growth polymers grow in a single direction from one end of the chain only and an initiator is typically used. In chain-growth polymerisation it is commonplace that once a growth at a chain end is terminated the end becomes un-reactive.

An example of one type of chain-growth polymerisation is the free-radical polymerisation reaction, for example the well-known polymerization of styrene (vinyl benzene) in the presence of benzoyl peroxide (as radical initiator) to produce polystyrene. Similarly, aluminum chloride may be used to initiate the polymerisation of isobutylene to form synthetic rubber. Other examples include the polymerization reactions of acrylates or methacryates.

A step-growth polymer is a polymer whose chain is formed during by the reaction of poly-functional monomers to form increasingly larger oligomers. Growth occurs throughout the matrix and the monomer level falls rapidly in the early stages of the reaction. No initiator is needed for a step growth polymerisation and the ends of the growing chain generally remain active at all times. Typically (but not always) a small molecule, which is often water, is eliminated in the polymerization process.

An example of step-growth polymerization is the formation of polyester by the reaction of dicarboxylic acids and glycols with elimination of water. Another example is the polymerisation of phenol and formaldehyde to produce "Bakelite". Other well known step-growth polymerisation reactions are the formation of polyesters, polyurethanes, polyureas, polyamides and polyethers.

It should be noted that chain-growth polymerisation and so-called "addition polymerisation" are different concepts. Addition polymerisation is where the reaction product is a polymer only. This may be contrasted with "condensation polymerisation" where a small molecule (the "condensate") is also produced. Polyurethane, for example, is produced by addition polymerisation of

(di)isocyanate compounds (R-N=C=O) with (di)hydroxy compounds (HO-R) to form the urethane/carbamate linkage (R-NH-CO-O-R), but the reaction

mechanism is step-growth rather than chain-growth as there is molecular rearrangement without elimination of a small molecule.

Both chain-growth and step-growth have been used to prepare particles by polymerisation in which some of the components are present in the dispersed phase of an emulsion. In the case of chain-growth, all of the components may be present in droplets of the dispersed phase which, once initiated, react internally to form a particle. In the case of step-growth, components may be present both in the dispersed and the continuous phase to react at the dispersed phase surface to form a "shell" at the interface.

In US 2009/312222 particles are prepared using so-called "mini-emulsion" polymerisation, to give a particle with a size as from about 30 to 500 nm. The polymer comprises units derived from monomers that are capable of undergoing chain-growth free-radical polymerisation. GB 2432851 discloses particles derived from monomers that are capable of undergoing free-radical polymerisation.

GB 2432850 discloses core/shell particles in which both the core and the shell comprises monomer units which are derived from monomers that are capable of undergoing free-radical polymerisation.

Emulsion polymerisation can also be performed using step-growth reactions. US 4622267 discloses an interfacial polymerization technique for preparation of microcapsules. US 2002/169233 discloses an interfacial polymerization process wherein a microcapsule wall of a polyamide, an epoxy resin, a polyurethane, a polyurea or the like is formed at an interface between two phases. The core material is initially dissolved in a solvent and an aliphatic diisocyanate soluble in the solvent mixture is added. Subsequently, a non-solvent for the aliphatic diisocyanate is added until the turbidity point is just barely reached. This organic phase is then emulsified in an aqueous solution, and a reactive amine is added to the aqueous phase. The amine diffuses to the interface, where it reacts with the diisocyanate to form polymeric polyurea shells.

Microcapsules have been proposed in which the wall material comprises both a step-growth polymer and a chain-growth polymer.

US 2005/0153839 disclose microcapsules for use in the production of multicolour thermo-sensitive recording materials having polyurethane or polyurea walls. The polymer wall includes (via a covalent bond) a polymer obtained by radically polymerising at least a vinyl monomer further comprising a polyether. Preferably the raw materials for the walls are di-isocyanates. It should be noted that the vinyl polymer is included in the wall rather than being enclosed by it.

EP 2204155 discloses leak-proof, friable core-shell fragrance microcapsules which have melamine-formaldehyde (step-growth polymer) shells and in which the core may optionally comprise, among other possibilities, high density organic oil- soluble ingredients which may be prepared by any standard means such as radical polymerisation of unsaturated monomers such as vinyl or acrylic

monomers (which are chain-growth polymers). Alternatively the polymers may be prepared by condensation reactions such as those leading to polyethers or polyesters (which are step-growth polymers). The fragrance comprises at least one cyclic fragrance material. The reason for including these pre-formed high density materials is to match the density of the micro-capsules with that of the composition in which they are used, to prevent separation. An effective encapsulate for a benefit agent, for example a benefit agent such as perfume, should have the following properties:

• It should have a target loading of 20%w/w benefit agent or better and be easy to load;

• It should minimise leakage of the benefit agent into a product during

manufacture and on storage;

• It should not require modification of the bulk formulation, for example by requiring the presence of structuring and/or suspending systems;

· Ideally, the encapsulate should deposit well onto substrates;

• The encapsulate should control the release of benefit agent.

Brief Description of the Invention

We have now determined that improved particles for treatment of skin and hair comprise a shell which comprises a step-growth polymer and at least one region interior to the shell which comprises a chain-growth polymer. The shell may be formed by interfacial polymerisation, and the interior region by radical

polymerisation. Advantageously, the polymer which comprises the shell is formed prior to the "internal" polymer. In the alternative the core is formed first and the shell added later.

Accordingly, the present invention provides a personal care composition for direct application to a surface selected from human skin and/or hair, including from 0.001 wt % to 10 wt %, preferably from 0.0001 wt % to 9 wt %, by weight of the total composition, of a core-shell benefit agent carrier particle comprising:

a) a core, optionally comprising a benefit agent; at least one polymer shell surrounding the core,

a deposition aid, attached to the outer shell and not removed by exposure to water, said deposition aid comprising at least one polysaccharide selected from the group consisting of poly-mannan, poly-glucan, poly-glucomannan, poly-xyloglucan, poly-galactomannan, dextran, hydroxyl -propyl cellulose, hydroxy-propyl methyl cellulose, hydroxy-ethyl methyl cellulose, hydroxy- propyl guar, hydroxy-ethyl ethyl cellulose or methyl cellulose, with the proviso that the particle is not a particle having an average diameter of less than 50 micron comprising; at least one shell formed by a step-growth polymerisation reaction, interior to said shell, at least one region formed by chain-growth polymerisation reaction which does not involve an isocyanate, wherein the shell is polymerised prior to the core. Such particles have an inner region, typically forming a "core" which provides a sink for the benefit agent and a "shell" which protects the benefit agent and regulates the flow of benefit agent into and out of the core. Thus, the particle can be a carrier which controls thermodynamic (rather than kinetic) partition of the benefit agent between the interior region and elsewhere. This is particularly advantageous where late-stage addition of perfume is required as the particles and the perfume may be dosed into the product separately.

Typically, the step-growth polymerisation reaction used to form the shell is not a condensation polymerisation, and, more preferably, involves an isocyanate monomer, more preferably a urethane and/or a urea. Isocyanate monomers are reactive, enable high monomer conversion, and form a robust, glassy shell which can survive drying and other processing. As noted above, isocyanate monomers react by a step-growth mechanism but are categorised as an addition polymer by virtue of no small molecule being eliminated during polymerisation. Preferably, the chain-growth polymerisation reaction used to form the inner region is a radical polymerisation reaction, more preferably of at least one ethylenically unsaturated monomer, conveniently a vinyllic monomer, most preferably selected from acrylate or methacryate. Such materials enable the compatibility of the inner region (typically a "core") and the benefit agent to be optimised for desirable delivery parameters. In particular the solubility parameters of the benefit agent and the chain-growth polymer comprising the inner region may be matched to achieve improved absorption and/or delivery. The deposition aid is substantive to surfaces such as skin and hair. By use of such a deposition aid, the efficiency of delivery to skin and hair may be enhanced. "Care" as used in the claims of the present specification is intended to include cleaning as well as conditioning, moisturising and other treatments of the skin and or hair.

Typically, the particle has an average diameter of less than 10 micron, and preferably an average diameter of less than 1 micron, more preferably less than 500nm. One benefit of small particles is that they are less visible in clear products. Another useful benefit is that sizes below 500nm favour deposition on fibrous substrates and can allow formulation without the need for suspending and/or structuring systems. Most typically the particles are in the size range of 50-500 nm, preferably 100-300 nm, the size being controllable by the presence of surfactant in the polymerisation mixture. Advantageously the particle comprises a hydrophobic benefit agent.

As noted above the benefit agent may be introduced into the particle during particle formation, or may be introduced into "empty" particles after particle formation. Particles for use in the personal care compositions of the present invention may be formed from an emulsion by carrying out an interfacial step-growth

polymerisation first to form a shell under conditions where the chain-growth polymerisation is inhibited. Subsequently, the conditions are changed such that the material within the shell undergoes the chain-growth polymerisation. A suitable change in conditions is to increase the temperature from one at which the chain growth reaction is inhibited to one at which it proceeds. Other possible changes of conditions would be, for example, to use a chain-growth reaction which is light dependent rather than temperature dependent.

A preferred embodiment of the present invention provides a personal care composition comprising a particle obtainable by a method comprising: forming an emulsion, preferably having a mean dispersed particle size diameter of less than 1000nm, more preferably less than 500nm and having a dispersed non-aqueous phase comprising: i) a first co-monomer, preferably an isocyanate monomer, capable of step-growth polymeriation with a suitable second co-monomer, ϋ) an optional benefit agent, preferably an organoleptic benefit agent, ill) at least one monomer, preferably acrylate or methacryate, capable of chain-growth polymerisation, and

iv) a radical initiator, preferably peroxide or azo-, which is not significantly active at the temperature at which the first co-monomer undergoes step-growth polymerisation and, a continuous aqueous phase comprising: i) water,

ii) an emulsifying agent iii) a second co-monomer for the first co-monomer, preferably a diol or diamine, b) maintaining the emulsion at a temperature at which the step-growth

polymerisation occurs but not the chain growth polymerisation, and, subsequently, c) maintaining the emulsion at a temperature at which the chain-growth

polymerisation proceeds.

Preferably the first and second co-monomers react by a step-growth mechanism to form a poly-urethane (which may be illustrated by the approximate formula (-Ri-NH-CO-O-R₂-O-CO-NH-)_n) or a polyurea (which may be illustrated by the approximate general formula (-NH-CO-NH-R-)_n).

The monomer capable of chain-growth polymerisation is preferably ethylenically unsaturated, more preferably vinyllic. In the alternative, a ring-opening mechanism may be used. Advantageously, the above described method provides a potentially "one-pot" reaction which has the advantages of simplicity and reduced losses: i.e. the shell is formed by step-growth polymerisation at the interface of the emulsion droplets and the core is subsequently formed within the shell by an in-situ chain-growth polymerisation.

In the alternative the core may be formed first and the shell added in a

subsequent step with the deposition aid added during the formation of the shell.

Conveniently the particle further comprises a cross-linking agent, derived from a more than di-functional species having isocyanate, alcohol, amine functionality, and/or a more than mono-functional vinyllic monomer. Tri- and tetra- functional materials are preferred. The benefit of cross-linking agents is to increase robustness of either the shell or the inner region, and or decrease permeability. Cross-linking agents in the shell, particularly the poly-functional isocyanates, can dramatically reduce the possibility of leakage. Cross linking agents in the inner region can modify interaction of the "core" with the benefit agent, e.g. by modification of the solubility parameters.

A further aspect of the invention provides a process for the manufacture of a product comprising the particles according to the invention wherein the particles and the benefit agent are added separately to the formulation.

A further aspect of the present invention provides a method of treatment of a substrate, preferably wherein the substrate is selected from skin and/or hair, which includes the step of treating the substrate with a composition comprising particles according to the present invention.

Because of the robustness of the particles of the present invention, they can be formulated in products which have relatively harsh environments, such as high solvent content. The particles are also resistant to mechanical disruption such as may occur during product processing, transport, storage or use, particularly on application to the substrate.

The personal care composition is preferably selected from a skin treatment composition, a hair treatment composition, a deodorant and an antiperspirant, more preferably selected from a skin treatment composition and a hair treatment composition and even more preferably selected from a shampoo, a hair conditioner, a skin care product and a skin cleansing product. Particularly preferred products do not comprise LAS (linear alkyl benzene sulphonate) based anionic surfactant. As the particles for use in the compositions of the present invention can be small, especially below 500nm, they do not require suspending agents and thereby simplify product formulation and enable the production of clear/transparent products. Mini-emulsion particles can be a small as 50nm.

Detailed Description of the Invention

In order that the present invention may be further and better understood it will be further described below with reference to specific embodiments of the invention and further preferred and/or optional features. All amounts quoted are wt.% of total composition unless otherwise stated.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about".

Step Growth Polymers:

As noted above the step-growth polymer (which comprises the "shell") is formed from monomers by the formation of increasingly larger oligomers. Suitable classes of such monomers are found in the group consisting of the melamine/ urea/formaldehyde class, the isocyanate/diol class (especially the polyurethanes) and polyesters. Preferred are the melamine/urea formaldehyde class, the isocyanate/diamine class and other classes of monomers which form

polyurethanes.

Suitable monomer compounds include: urea, thiourea, dicyan-diamide, melem (1 ,3,4,6,7,9,9b-Heptaazaphenalene), melam (N2-(4,6-diamino-1 ,3,5-triazin-2-yl)- 1 ,3,5-Triazine-2,4,6-Triannine), melon (where the heptazine is polymerized with the tri-s-triazine units linked through an amine link), ammeline (4,6-Diamino-2- hydroxy-1 ,3,5-triazine), ammelide (6-Amino-2,4-Dihydroxy-l,3,5-Triazine), substituted melamines, guanamines, or mixtures thereof.

Substituted melamines include the alkyl melamines and aryl melamines which can be mono, di-, or tri-substituted. In the alkyl-substituted melamines, each alkyl group can contain from 1 to 6 carbons, preferably from 1 to 4 carbons. Representative examples of some alkyl-substituted melamines are

monomethylmelamine, dimethyl melamine, trimethyl melamine, monoethyl melamine, and 1 -methyl-3-propyl-5-butyl melamine.

In the aryl-substituted melamines, each aryl group can contain 1 -2 phenyl moieties and, preferably, 1 phenyl moiety. Typical examples of an aryl-substituted melamine are monophenyl melamine or diphenyl melamine.

Especially suitable step-growth polymers are those whose isocyanate monomers are aromatic polyisocyanates, aliphatic polyisocyanates, and mixtures thereof.

Suitable, aromatic polyiscocyanates comprise, but are not limited to, 2,4-and 2,6- toluene diisocyanate, naphthalene diisocyanate, diphenyl methane diisocyanate and triphenyl methane-ρ,ρ'ρ"- trityl triisocyanate, polymethylene polyphenylene isocyanate, 2,4,4'-diphenylether triisocyanate, 3,3'-dimethyl-4,4'- diphenyl diisocyanate, 3,3'-dimethoxy-4,4'diphenyl diisocyanate, and 4,4'4"- triphenylmethane triisocyanate.

Suitable aliphatic polyisocyanates comprise, but are not limited to

Dicyclohexylmethane 4,4 '-diisocyanate, hexamethylenel,6-diisocyanate, isophorone diisocyanate, trimethyl- hexamethylene diisocyanate, trimer of hexamethylenel,6-diisocyanate, trimer of isophorone diisocyanate, 1 ,4- cyclohexane diisocyanate, urea of hexamethylene diisocyanate, trimethylene diisocyanate, propylene- 1 ,2-diisocyanate and butylenel,2-diisocyanate and mixtures thereof.

The preferred isocyanate materials are: 2,4- and 2,6-toluene diisocyanate and isophorone diisocyanate.

The co-monomer used in the step-growth polymerisation is typically a diol or a diamine.

Suitable diols can comprise, but are not limited to, low molecular weight polymers such as ethylene glycol, diethylene glycol, propylene glycol, 1 ,4-butanediol„ 2,3- butane diol, neopentyl glycol, 1 ,6-hexanediol, dipropylene glycol, cyclohexyll,4- dimethanol, 1 ,8-octanediol; high molecular weight polyols such as polyethylene glycol, polypropylene glycols, polytetramethylene glycols (PTMG) having average molecular weight in the range of 200 to 2000, polyester diols, diols containing carboxyl groups such as dimethylol propionic acid (DMPA) and dimethylol butanoic acid (DMBA) and mixtures thereof.

The preferred diol materials are ethylene glycol, diethylene glycol, propylene glycol, 1 ,4- butanediol, 2,3-butane diol, neopentyl glycol, 1 ,6-hexanediol, and dipropylene glycol. The more hydrophobic diols (particularly 1 ,4- butanediol, 2,3- butane diol, neopentyl glycol and 1 ,6-hexanediol) are preferred as it is generally easier to get a stable emulsion with these materials and thereby a more efficient polymerisation.

Suitable diamines can comprise amines such as ethylene diamine (EDA), phenylene diamine, toluene diamine, hexamethylene diamine, diethylenetriamine, tetraethylene pentaamine, pentamethylene hexamine, 1 ,6-hexane diamine, Methylene tetramine, 2,4-diamino-6-methyl- 1 ,3,5 thazine 1 ,2- diaminocyclohexane, 4,4'-diamino-diphenylnnethane, 1 ,5-diaminonaphthalene,

2,4,4'- triaminodiphenylether, bis(hexa-methylenetriannine), 1 ,4,5,8- tetraaminoanthraquinone, isophorone diamine, diamino propane and

diaminobutane, and mixtures thereof. The preferred diamine materials are ethylene diamine and 1 ,6-hexane diamine.

Mole ratios of the co-monomers are preferably selected such that the water soluble monomer is present in up to 10 mol% excess over the oil soluble co- monomer, preferably 1 to 8 mol% excess, more preferable 2 to 5 mol% excess. It is believed that this ensures complete reaction of isocyanate monomer.

Cross-linking Agents for Step Growth Polymerisation:

As noted above cross-linking agents advantageously improve the properties of the shell. Many cross-linking agents suitable for use in step-growth polymerisation are known. Cross-linking agents significantly reduce the leakage of benefit agents from the particles. Cross-linking agents are preferably polyamines and polyols.

Preferred amine-functional cross-linking agents contains more than two amine functionalities such as tetraethylene pentamine, triethylene tetraamine, 2,4,4'- triaminodiphenylether, bis(hexamethylene triamine), 1 ,4,5,8-tetraamino

anthraquinone and diethylene triamine (DETA), and mixtures thereof.

Preferred alcohol-functional cross-linking agents contain more than two alcohol functionalities such as glycerol, pentaerythritol, and 1 ,1 ,1 trihydroxmethylpropane.

A particularly preferred cross-linking agent is polyphenylisocyanate.

The preferred levels of cross-linking agent are 1 -50 mol%, more preferably 2-35 mol% of the step-growth monomers. Chain Growth Polymers:

As noted above at least one region interior to the shell is formed by chain-growth polymerisation. Typically this will comprise a single solid region making-up the "core" of the particle.

Free-radical polymerisation (FRP) is a suitable method of chain-growth

polymerisation. In FRP a mono-functional monomer is polymerised in the presence of free-radical initiator and, optionally, a chain transfer agent. Chain transfer agents can act to reduce the average molecular weight of the final polymer.

The use of a separate chain transfer agent and an initiator is preferred. However, some molecules can perform both these functions.

The free-radical initiator can be any molecule known to initiate free-radical polymerisation such as azo-containing molecules, persulfates, redox initiators, peroxides, benzyl ketones. These initiators may be activated via thermal, photolytic or chemical means. In the method of the present invention, thermal activation is preferred.

Examples of suitable initiators include but are not limited to 2,2'- azobisisobutyronitrile (AIBN), azobis(4-cyanovaleric acid), , benzoyl peroxide, cumylperoxide, 1 -hydroxy-cyclohexyl phenyl ketone, hydrogen peroxide/ascorbic acid.

So-called 'iniferters' such as benzyl-N,N-diethyldithio-carbamate can also be used. In some cases, more than one initiator may be used. The preferred initiators are: 2,2'-Azobis(2-methylbutyro-nitrile), 2,2'-Azobis(2.4- dimethyl valeronitrile), 1 ,1 '-Azobis(cyclohexane -1 -carbonitrile) and t-butyl hydro- peroxide/ascorbic acid as these minimise the production of unwanted bi-products. Preferably, the residue of the initiator in a free-radical polymerisation comprises 0 to 5% w/w, preferably 0.01 to 5% w/w and especially 0.01 to 3% w/w, of the resulting copolymer based on the total weight of the monomers.

The chain transfer agent is preferably a thiol-containing molecule and can be either mono-functional or multi-functional. The agent may be hydrophilic, hydrophobic, amphiphilic, anionic, cationic, neutral or zwitterionic. The molecule can also be an oligomer containing a thiol moiety.

Suitable thiols include but are not limited to C2-C18 alkyl thiols such as dodecane thiol, thioglycolic acid, thioglycerol, cysteine and cysteamine. Thiol-containing oligomers may also be used such as oligo(cysteine) or an oligomer which has been post-functionalised to give a thiol group(s), such as oligoethylene glycolyl (di)thio glycollate. Xanthates, dithioesters, and dithiocarbonates may also be used, such as cumyl phenyldithioacetate.

Alternative chain transfer agents may be any species known to limit the molecular weight in a free-radical addition polymerisation. Thus the chain-transfer agent may also be a hindered alcohol, halocarbon, alkyl halide or a transition metal salt or complex, or similar free-radical stabiliser. Catalytic chain transfer agents such as those based on transition metal complexes such as cobalt bis(borondi- fluorodimethyl-glyoximate) may also be used.

More than one chain transfer agent may be used in combination. The residue of the chain transfer agent may comprise 0 to 20 mole%, preferably 0 to 10 mole% and especially 0 to 3 mole%, of the copolymer (based on the number of moles of mono-functional monomer). In some cases, for example in the case of some so-called living polymerisation methods, a chain transfer agent is not required.

Monomers for the chain-growth polymerisation may comprise any carbon-carbon unsaturated (or cyclic) compound which can form an addition polymer, e.g. vinyl and allyl compounds. The mono-functional monomer may be hydrophilic, hydrophobic, amphiphilic, anionic, cationic, neutral or zwitterionic in nature. Thus, the mono-functional monomer may be selected from but not limited to monomers such as vinyl acids, vinyl acid esters, vinyl aryl compounds, vinyl acid anhydrides, vinyl amides, vinyl ethers, vinyl amines, vinyl aryl amines, vinyl nitriles, vinyl ketones, and derivatives of the aforementioned compounds as well as

corresponding allyl variants thereof.

Other suitable mono-functional monomers for the chain-growth polymer include hydroxyl-containing monomers and monomers which can be post-reacted to form hydroxyl groups, acid-containing or acid functional monomers, zwitterionic monomers and quaternised amino monomers.

Oligomeric or oligo-functionalised monomers may also be used, especially oligomeric (meth)acrylic acid esters such as mono(alk/aryl) (meth)acrylic acid esters of oligo[alkyleneglycol] or oligo[dimethylsiloxane] or any other mono-vinyl or allyl adduct of a low molecular weight oligomer. Mixtures of more than one monomer may also be used.

Preferred vinyl acids and derivatives thereof include (meth)acrylic acid and acid halides thereof such as (meth)acryloyl chloride. Preferred vinyl acid esters and derivatives thereof include C1 -20 alkyl(meth)acrylates (linear & branched) such as methyl (meth)acrylate, stearyl (meth)acrylate and 2-ethyl hexyl (meth)acrylate, aryl(meth)acrylates such as benzyl (meth)acrylate, tri(alkyloxy)silylalkyl (meth)acrylates such as

trimethoxysilylpropyl(meth)acrylate and activated esters of (meth)acrylic acid such as N-hydroxysuccinamido (meth)acrylate. Vinyl aryl compounds and derivatives thereof include styrene, acetoxystyrene, styrene sulfonic acid, vinyl pyridine, vinylbenzyl chloride and vinyl benzoic acid. Vinyl acid anhydrides and derivatives thereof include maleic anhydride. Vinyl amides and derivatives thereof include (meth)acrylamide, N-vinyl pyrrolidone, N-vinyl formamide, (meth)acrylamidopropyl trimethyl ammonium chloride, [3-((meth)acrylamido)propyl]dimethyl ammonium chloride, 3-[N-(3-(meth) acrylamidopropyl)-N,N-dimethyl]aminopropane sulfonate, methyl (meth) acrylamidoglycolate methyl ether and N-isopropyl(meth)acrylamide. Vinyl ethers and derivatives thereof include methyl vinyl ether. Vinyl amines and derivatives thereof include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, diisopropylaminoethyl (meth)acrylate, mono-t-butylaminoethyl (meth)acrylate, morpholinoethyl(meth)acrylate and monomers which can be post- reacted to form amine groups, such as vinyl formamide. Vinyl aryl amines and derivatives thereof include vinyl aniline, vinyl pyridine, N-vinyl carbazole and vinyl imidazole. Vinyl nitriles and derivatives thereof include (meth)acrylonitrile. Vinyl ketones and derivatives thereof include acreolin.

Hydroxyl-containing monomers include vinyl hydroxyl monomers such as hydroxyethyl (meth)acrylate, hydroxy propyl (meth)acrylate, glycerol

mono(meth)acrylate and sugar mono(meth)acrylates such as glucose

mono(meth)acrylate. Monomers which can be post-reacted to form hydroxyl groups include vinyl acetate, acetoxystyrene and glycidyl (meth)acrylate. Acid- containing or acid functional monomers include (meth)acrylic acid, styrene sulfonic acid, vinyl phosphonic acid, vinyl benzoic acid, maleic acid, fumaric acid, itaconic acid, 2-(meth)acrylamido 2-ethyl propanesulfonic acid, mono-2- ((meth)acryloyloxy)ethyl succinate and ammoniunn sulfatoethyl (meth)acrylate. Zwitterionic monomers include (meth)acryloyl oxyethylphosphoryl choline and betaines, such as [2-((meth)acryloyloxy)ethyl] dimethyl-(3-sulfopropyl)ammonium hydroxide. Quaternised amino monomers include (meth)acryloyloxyethyltri- (alk/aryl)ammonium halides such as (meth)acryloyloxyethyltrimethyl ammonium chloride.

Oligomeric (or polymeric) monomers include oligomeric (meth)acrylic acid esters such as mono(alk/aryl)oxyoligo-alkyleneoxide(meth)acrylates and mono(alk/aryl)o xyoligo-dimethyl-siloxane(meth)acrylates. These esters include monomethoxy oligo(ethyleneglycol) mono(meth)acrylate, monomethoxy oligo(propyleneglycol) mono(meth)acrylate, monohydroxy oligo(ethyleneglycol) mono(meth)acrylate and monohydroxy oligo(propyleneglycol) mono(meth)acrylate.

Further examples include vinyl or allyl esters, amides or ethers of pre-formed oligomers formed via ring-opening polymerisation such as oligo(caprolactam) or oligo-(caprolactone), or oligomers formed via a living polymerisation technique such as oligo(1 ,4-butadiene). The polymeric monomers are the same, save that the oligomers are polymers.

Macromonomers are generally formed by linking a polymerisable moiety, such as a vinyl or allyl group, to a pre-formed monofunctional polymer via a suitable linking unit such as an ester, an amide or an ether. Examples of suitable polymers include mono functional poly(akylene oxide) such as

monomethoxy[poly(ethyleneoxide) or monomethoxy [poly-(propyleneoxide), silicones such as poly(dimethylsiloxane), polymers formed by ring-opening polymerisation such as poly(caprolactone) or poly(caprolactam) or mono- functional polymers formed via living polymerisation such as poly(1 ,4-butadiene). Preferred macromononners include monomethoxy[poly-(ethyleneglycol)] mono (methacrylate), monomethoxy[poly-(propyleneglycol)] mono(methacrylate), poly (dimethylsiloxane) monomethacrylate. The corresponding allyl monomers to those listed above can also be used where appropriate.

More preferred monomers include: amide-containing monomers such as

(meth)acrylamide, N,N'-dimethyl(meth)acrylamide, N and or N'-di(alkyl or aryl) (meth)acrylamide, N-vinyl pyrollidone, (meth)acrylamidopropyl trimethyl ammonium chloride, [3-(methacroylamino) propyl]dimethyl ammonium chloride, 3- [N-(3-methacrylamido-propyl)-N,N-dimethyl]-aminopropane sulfonate, 4-(2- acrylamido-2-methylpropyl-dimethylammonio) butanoate, methyl

acrylamidoglycolate methyl ether and N-isopropyl-(meth)acrylamide; (meth)acrylic acid derivatives such as (meth)acrylic acid, (meth)acryoloyl chloride (or any halide), (alkyl/aryl) (meth)acrylate, oligo-functionalised monomers such as monomethoxy poly(ethyleneglycol) monomethacrylate or monomethoxy poly(propyleneglycol) mono(meth)acrylate, glycerol mono(meth)acrylate, glycidyl (meth)acrylate and sugar mono(meth)acrylates such as glucose

mono(meth)acrylate; vinyl amines such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, t-butylamino (meth)acrylate,

morpholinoethylmethacrylate, or vinyl aryl amines such as vinyl aniline, vinyl pyridine, N-vinyl carbazole, vinyl imidazole; vinyl aryl monomers such as styrene, vinyl benzyl chloride, vinyl toluene, a-methyl styrene, styrene sulfonic acid and vinyl benzoic acid; vinyl hydroxyl monomers such as hydroxyethyl (meth)acrylate, hydroxy propyl (meth)acrylate, glyceryl (meth)acrylate or monomers which can be post-functionalised into hydroxyl groups such as vinyl acetate or acetoxy styrene can also be used; acid-containing monomers such as (meth)acrylic acid, styrene sulfonic acid, vinyl phosphonic, maleic acid, fumaric acid, itaconic acid, 2- acrylamido 2-ethyl propanesulfonic acid and mono-2-(methacryloyloxy)ethyll succinate. Or aryl/alkyl esters thereof. Or carboxylic anhydride containing monomers such as maleic anhydride; zwitterionic monomers such as

(meth)acryloyloxyethyl-phosphoryl choline, quaternised amino monomers such as methacryloyl-oxyethyltrimethyl ammonium chloride.

The corresponding allyl monomer, where applicable, can also be use in each case.

Hydrophobic monomers include: vinyl aryl compounds such as styrene and vinylbenzyl chloride; (meth)acrylic acid esters such as mono-t-butylaminoethyl (meth)acrylate, C1 -20 alkyl(meth)acrylates (linear & branched), aryl(meth) acrylates such as benzyl methacrylate; oligomeric (meth)acrylic acid esters such as mono(alk/aryl)oxyoligo-[dimethylsiloxane (meth)acrylate] and tri(alkyloxy)- silylalkyl (meth)acrylates such as trimethoxysilylpropyl-(meth)acrylate.

Functional monomers, i.e. monomers with reactive pendant groups which can be post or pre-modified with another moiety can also be used such as glycidyl (meth)acrylate, trimethoxysilylpropyl(meth)acrylate, (meth)acryloyl chloride, maleic anhydride, hydroxyalkyl (meth)acrylates, (meth)acrylic acid, vinylbenzyl chloride, activated esters of (meth)acrylic acid such as N-hydroxysuccinamido

(meth)acrylate and acetoxystyrene.

The copolymer may contain unreacted polymerisable groups from the

multifunctional monomer.

Especially preferred monomers for chain growth polymerisation are: C1-C20 linear or branched, alkyl, alkaryl or aryl acrylates and methacrylates. Ratio of Step-Growth to Chain Growth Polymer:

The weight fraction of step growth polymer in the combined step growth and chain growth polymers comprising the particle is typically 10% to 99%, preferably 15% to 80%, more preferably 25% to 75%.

Cross-linking Agents for Chain-Growth Polymerisation:

Cross-linking agents can be used to modify the properties of the chain-growth polymer. Suitable materials comprise a molecule containing at least two vinyl groups that may be polymerised. The molecule may be hydrophilic, hydrophobic, amphiphilic, neutral, cationic, zwitterionic or oligomeric. Examples include di- or multivinyl esters, di- or multivinyl amides, di- or multivinyl aryl compounds and di- or multivinyl alk/aryl ethers. Typically, in the case of oligomeric or multifunctional branching agents, a linking reaction is used to attach a polymerisable moiety to a di- or multifunctional oligomer or a di- or multifunctional group. The brancher may itself have more than one branching point, such as T-shaped divinylic oligomers. In some cases, more than one multifunctional monomer may be used. Macro cross-linkers or macro branchers (multifunctional monomers typically having a molecular weight of at least 1000 Daltons) are generally formed by linking a polymerisable moiety, such as a vinyl or aryl group, to a pre-formed multifunctional polymer via a suitable linking unit such as an ester, an amide or an ether. Examples of suitable polymers include di-functional poly(alkylene oxides) such as poly(ethyleneglycol) or poly(propylene glycol), silicones such as poly(dimethyl-siloxane)s, polymers formed by ring-opening polymerisation such as poly(caprolactone) or poly(caprolactam) or poly-functional polymers formed via living polymerisation such as poly(1 ,4-butadiene). Preferred macro branchers include poly(ethyleneglycol) di(meth)acrylate, poly(propyleneglycol) di(meth)acrylate, (meth)acryloxypropyl-terminated poly (dimethylsiloxane), poly(caprolactone) di(meth)acrylate and poly(caprolactam) di(meth)acrylamide.

The corresponding allyl monomers to those listed above can also be used where appropriate.

Preferred multifunctional monomers include but are not limited to divinyl aryl monomers such as divinyl benzene; (meth)acrylate diesters such as glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, propyleneglycol

di(meth)acrylate and 1 ,3-butylenedi(meth)acrylate; oligoalkylene oxide

di(meth)acrylates such as tetra ethyleneglycol di(meth)acrylate,

oligo(ethyleneglycol) di(meth)acrylate and oligo(propyleneglycol) di(meth)- acrylate; divinyl acrylamides such as methylene bis-acrylamide; silicone- containing divinyl esters or amides such as (meth)acryloxypropyl-terminated oligo (dimethyl-siloxane); divinyl ethers such as oligo (ethyleneglycol)-divinyl ether; and tetra- or tri-(meth)acrylate esters such as pentaerythritol tetra-(meth)acrylate, trimethylolpropane tri(meth)acrylate or glucose di- to penta(meth)acrylate. Further examples include vinyl or allyl esters, amides or ethers of pre-formed oligomers formed via ring-opening polymerisation such as oligo(caprolactam) or oligo- (caprolactone), or oligomers formed via a living polymerisation technique such as oligo(1 ,4-butadiene). Especially preferred cross-linkers are divinyl benzene, ethylene glycol

di(meth)acrylate and trimethylolpropane tri(meth)acrylate.

Levels of cross-linker are typically 0-75, preferably 0.0001 to 50, more preferably 0.0001 to 25 mol %. Benefit Agents:

Various benefit agents can be incorporated into the particles. Where the end use of the particles is in connection with a surfactant-containing system, any compatible benefit agent which can provide a benefit to a substrate which is treated with a surfactant composition can be used. Advantages of the particles of the invention in the presence of surfactant are a good retention of the benefit agent on storage of a formulation and controllable release of the benefit agent during and after product usage.

Preferred examples include flavours and fragrances, conditioning agents (for example water-insoluble quaternary ammonium materials and/or silicones), sunscreens, colour protection agents, ceramides, antioxidants, dyes, lubricants, unsaturated oils, emollients/moisturiser, insect repellents and/or antimicrobial agents and more preferably, flavours and fragrances, conditioning agents (for example water-insoluble quaternary ammonium materials and/or silicones), sunscreens, colour protection agents, ceramides, antioxidants, dyes,

emollients/moisturiser, insect repellents and/or antimicrobial agents. For skin compositions the preferred benefit agents include one or more of fragrances, sunscreens, skin lightening agents, antimicrobials, oils and insect repellents. For hair compositions the list of preferred benefit agents is the same with the addition of colour protection agents and dyes. Preferred antimicrobials include Triclosan™, climbazole, octapyrox, ketoconizole, zinc pyrithione, and quaternary ammonium compounds.

Preferred sunscreens and/or skin lightening agents are vitamin B3 compounds. Suitable vitamin B3 compounds are selected from niacin, niacinamide, nicotinyl alcohol, or derivatives or salts thereof. Other vitamins which act as skin lightening agents can be advantageously included in the skin lightening composition to provide for additional skin lightening effects. These include vitamin B6, vitamin C, vitamin A or their precursors. Mixtures of the vitamins can also be employed in the composition of the invention. An especially preferred additional vitamin is vitamin B6. Other non-limiting examples of skin lightening agents useful herein include adapalene, aloe extract, ammonium lactate, arbutin, azelaic acid, butyl hydroxy anisole, butyl hydroxy toluene, citrate esters, deoxyarbutin, 1 ,3 diphenyl propane derivatives, 2, 5 di hydroxyl benzoic acid a nd its derivatives, 2-(4-acetoxyphenyl)- 1 ,3 d itha ne, 2-(4- Hydroxylphenyl)-1 ,3 dithane, ellagic acid, gluco pyranosyl-1 - ascorbate, gluconic acid, glycolic acid, green tea extract, 4-Hydroxy-5-methyl- 3[2H]-furanone, hydroquinone, 4 hydroxyanisole and its derivatives, 4-hydroxy benzoic acid derivatives, hydroxycaprylic acid, inositol ascorbate, kojic acid, lactic acid, lemon extract, linoleic acid, magnesium ascorbyl phosphate, 5-octanoyl salicylic acid, 2,4 resorcinol derivatives, 3,5 resorcinol derivatives, salicylic acid, 3,4,5 trihydroxybenzyl derivatives, and mixtures thereof. Preferred sunscreens useful in the present invention are 2-ethylhexyl-p- methoxycinnamate, butyl methoxy dibenzoylmethane, 2-hydroxy-4- methoxybenzophenone, octyl dimethyl- p-aminobenzoic acid and mixtures thereof. Particularly preferred sunscreen is chosen from 2-ethyl hexyl-p-methoxycinnamate, 4,- t-butyl-4'- methoxydibenzoyl- methane or mixtures thereof. Other conventional sunscreen agents that are suitable for use in the skin lightening composition of the invention include

2-hydroxy-4-methoxybenzophenone, octyldimethyl- p-a mi nobenzoic acid, digalloyltrioleate, 2,2-dihydroxy-4- methoxybenzophenone, ethyl-4- (bis(hydroxypropyl)) aminobenzoate, 2- ethylhexyl-2- cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate, glyceryl- p-aminobenzoate, 3,3,5- trimethylcyclohexyl- salicylate, methylanthranilate, p-dimethyl-aminobenzoic acid or aminobenzoate, 2-ethylhexyl-p-dimethyl- amino-benzoate, 2-phenylbenzimidazole-5- sulfonic acid, 2-(p- dimethylaminophenyl)-5-sulfonic benzoxazoic acid and mixtures of these compounds. Preferred anti-oxidants include vitamin E, retinol, antioxiants based on

hydroxytoluene such as Irganox™ or commercially available antioxidants such as the Trollox™ series. Perfume and fragrance materials (which include pro-fragrances) are a particularly preferred benefit agent.

The pro-fragrance can, for example, be a food lipid. Food lipids typically contain structural units with pronounced hydrophobicity. The majority of lipids are derived from fatty acids. In these 'acyl' lipids the fatty acids are predominantly present as esters and include mono-, di-, triacyl glycerols, phospholipids, glycolipids, diol lipids, waxes, sterol esters and tocopherols. In their natural state, plant lipids comprise antioxidants to prevent their oxidation. While these may be at least in part removed during the isolation of oils from plants some antioxidants may remain. These antioxidants can be pro-fragrances. In particular, the carotenoids and related compounds including vitamin A, retinol, retinal, retinoic acid and provitamin A are capable of being converted into fragrant species including the ionones, damascones and damscenones. Preferred pro-fragrance food lipids include olive oil, palm oil, canola oil, squalene, sunflower seed oil, wheat germ oil, almond oil, coconut oil, grape seed oil, rapeseed oil, castor oil, corn oil, cottonseed oil, safflower oil, groundnut oil, poppy seed oil, palm kernel oil, rice bran oil, sesame oil, soybean oil, pumpkin seed oil, jojoba oil and mustard seed oil. Perfume components which are odiferous materials are described in further detail below.

The perfume is typically present in an amount of from 10-85% by total weight of the particle, preferably from 15 to 75% by total weight of the particle. The perfume suitably has a molecular weight of from 50 to 500Dalton. Pro-fragrances can be of higher molecular weight, being typically 1 -10 kD. Useful components of the perfume include materials of both natural and synthetic origin. They include single compounds and mixtures. Specific examples of such components may be found in the current literature, e.g., in Fenaroli's Handbook of Flavour Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand; or Perfume and Flavour Chemicals by

S. Arctander 1969, Montclair, N.J. (USA). These substances are well known to the person skilled in the art of perfuming, flavouring, and/or aromatizing consumer products, i.e., of imparting an odour and/or a flavour or taste to a consumer product traditionally perfumed or flavoured, or of modifying the odour and/or taste of said consumer product.

By perfume in this context is not only meant a fully formulated product fragrance, but also selected components of that fragrance, particularly those which are prone to loss, such as the so-called 'top notes'.

Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80 [1955]). Examples of well known top-notes include citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol. Top notes typically comprise 15-25%wt of a perfume composition and in those embodiments of the invention which contain an increased level of top-notes it is envisaged at that least 20%wt would be present within the particle.

Typical perfume components which it is advantageous to employ in the

embodiments of the present invention include those with a relatively low boiling point, preferably those with a boiling point of less than 300, preferably 100-250 Celsius.

It is also advantageous to encapsulate perfume components which have a low LogP (i.e. those which will be partitioned into water), preferably with a LogP of less than 3.0. These materials, of relatively low boiling point and relatively low LogP have been called the "delayed blooming" perfume ingredients and include the following materials:

Allyl Caproate, Amyl Acetate, Amyl Propionate, Anisic Aldehyde, Anisole,

Benzaldehyde, Benzyl Acetate, Benzyl Acetone, Benzyl Alcohol, Benzyl Formate, Benzyl Iso Valerate, Benzyl Propionate, Beta Gamma Hexenol, Camphor Gum, Laevo-Carvone, d-Carvone, Cinnamic Alcohol, Cinamyl Formate, Cis-Jasmone, cis-3-Hexenyl Acetate, Cuminic Alcohol, Cyclal C, Dimethyl Benzyl Carbinol, Dimethyl Benzyl Carbinol Acetate, Ethyl Acetate, Ethyl Aceto Acetate, Ethyl Amyl Ketone, Ethyl Benzoate, Ethyl Butyrate, Ethyl Hexyl Ketone, Ethyl Phenyl Acetate, Eucalyptol, Eugenol, Fenchyl Acetate, Flor Acetate (tricyclo Decenyl Acetate), Frutene (tricyclco Decenyl Propionate), Geraniol, Hexenol, Hexenyl Acetate, Hexyl Acetate, Hexyl Formate, Hydratropic Alcohol, Hydroxycitronellal, Indone, Isoamyl Alcohol, Iso Menthone, Isopulegyl Acetate, Isoquinolone, Ligustral, Linalool, Linalool Oxide, Linalyl Formate, Menthone, Menthyl Acetphenone, Methyl Amyl Ketone, Methyl Anthranilate, Methyl Benzoate, Methyl Benyl

Acetate, Methyl Eugenol, Methyl Heptenone, Methyl Heptine Carbonate, Methyl Heptyl Ketone, Methyl Hexyl Ketone, Methyl Phenyl Carbinyl Acetate, Methyl Salicylate, Methyl-N-Methyl Anthranilate, Nerol, Octalactone, Octyl Alcohol, p- Cresol, p-Cresol Methyl Ether, p-Methoxy Acetophenone, p-Methyl

Acetophenone, Phenoxy Ethanol, Phenyl Acetaldehyde, Phenyl Ethyl Acetate, Phenyl Ethyl Alcohol, Phenyl Ethyl Dimethyl Carbinol, Prenyl Acetate, Propyl Bornate, Pulegone, Rose Oxide, Safrole, 4-Terpinenol, Alpha-Terpinenol, and /or Viridine.

It is commonplace for a plurality of perfume components to be present in a formulation. In the encapsulates of the present invention it is envisaged that there will be four or more, preferably five or more, more preferably six or more or even seven or more different perfume components from the list given of delayed blooming perfumes given above present in the particles. Another group of perfumes with which the present invention can be applied are the so-called 'aromatherapy' materials. These include many components also used in perfumery, including components of essential oils such as Clary Sage, Eucalyptus, Geranium, Lavender, Mace Extract, Neroli, Nutmeg, Spearmint, Sweet Violet Leaf and Valerian.

The volatile benefit agents also include insect repellent materials (where insect should be read broadly to include other pests which are arthropods but not strictly hexapods - for example ticks). Many of these materials overlap with the class of perfume components and some are odourless to humans or have a non-perfume odour. Commonly used repellents include: DEET (N,N-diethyl-m-toluamide), essential oil of the lemon eucalyptus (Corymbia citriodora) and its active compound p-menthane-3,8-diol (PMD), lcaridin, also known as Picaridin,

D-Limonene, Bayrepel, and KBR 3023, Nepetalactone, also known as "catnip oil", Citronella oil, Permethrin, Neem oil and Bog Myrtle. Known insect repellents derived from natural sources include: Achillea alpina, alpha-terpinene, Basil oil (Ocimum basilicum), Callicarpa americana (Beautyberry), Camphor, Carvacrol, Castor oil (Ricinus communis), Catnip oil (Nepeta species), Cedar oil (Cedrus atlantica), Celery extract (Apium graveolens), Cinnamon (Cinnamomum

Zeylanicum, leaf oil), Citronella oil (Cymbopogon fleusus), Clove oil (Eugenic caryophyllata), Eucalyptus oil (70%+ eucalyptol, also known as cineol), Fennel oil (Foeniculum vulgare), Garlic Oil (Allium sativum), Geranium oil (also known as Pelargonium graveolens), Lavender oil (Lavandula officinalis), Lemon eucalyptus (Corymbia citriodora) essential oil and its active ingredient p-menthane-3,8-diol (PMD), Lemongrass oil (Cymbopogon flexuosus), Marigolds (Tagetes species), Marjoram (Tetranychus urticae and Eutetranychus orientalis), Neem oil

(Azadirachta indica), Oleic acid, Peppermint (Mentha x piperita), Pennyroyal (Mentha pulegium), Pyrethrum (from Chrysanthemum species, particularly C. cinerariifolium and C. coccineum), Rosemary oil (Rosmarinus officinalis), Spanish Flag Lantana camara (Helopeltis theivora), Solanum villosum berry juice, Tea tree oil (Melaleuca alternifolia) and Thyme (Thymus species) and mixtures thereof.

The compositions of the invention preferably further comprise an additional benefit agent that is not encapsulated. The additional benefit agent can be selected from those described above for the optional benefit agent in the core of the particle. Preferred examples include flavours and fragrances, conditioning agents (for example water-insoluble quaternary ammonium materials and/or silicones), sunscreens, colour protection agents, ceramides, antioxidants, dyes, lubricants, unsaturated oils, emollients, moisturisers, insect repellents and/or antimicrobial agents. The most preferred additional benefit agent is a perfume.

Preparation Methods Polymerisation occurs in at least two phases. In which the shell and the core are formed. The shell can be polymerised after the core or the order of polymerisation can be reversed.

Core First:

In this approach the core is formed first and the shell is deposited onto the core. This method is followed in the examples given below.

Core Second:

In this approach polymerisation occurs in at least two phases. In an earlier of these phases a shell is formed by a step-growth polymerisation. This shell encloses and contains the reagents for the chain-growth reaction which occurs in a later phase. Temporal separation of these phases is accomplished by control of the reagents present and the reaction conditions.

Typically, at least one of the components of the shell-forming reaction is withheld from the initial reaction mixture and added gradually to control the progress of the reaction in the first phase.

Advantageously, the first phase of the reaction is performed under conditions in which the chain-growth reaction is inhibited. These conditions include a sufficiently low temperature (for a thermally activated reaction) or conditions of sufficiently low light (for a photo-activated reaction).

Once the shell-forming reaction has proceeded sufficiently, the conditions are modified (for example, by raising the temperature or exposing the reaction mixture to light) to cause the reaction to form the inner region to start.

The preferred method is one in which an emulsion is formed comprising the chain- growth polymer components in a non-aqueous dispersed phase and the step- growth polymer components are at the interface between the dispersed phase and the continuous aqueous phase.

Typically the aqueous phase comprises an emulsifying agent, and one of the co- monomers for the step-growth polymer. It may also contain any diol, alcohol or amine cross-linking agent.

The disperse phase comprises the chain-growth monomer, the initiator, any isocyanate or vinyl cross-linking agents, the other co-monomer for the step growth polymer and any optional benefit agent. The benefit agent may be present in the reaction mixture, at a level to give the benefit agent levels in the resulting particles at the levels disclosed above, although it is also possible to form "empty" particles and subsequently expose them to a benefit agent which can be adsorbed into the inner region.

Surface modification materials are generally added to the aqueous phase towards the end of the process, where, for example, further monomer(s) can be added to form further shell material and bind additional materials to the outside of the particle.

Emulsifying Agents

Many emulsifying agents are known for use in emulsion polymerisation. Suitable emulsifying agents for use in the polymerisation process may comprise, but are not limited to, non-ionic surfactants such as polyvinylpyrrolidone (PVP), polyethylene glycol sorbitan monolaurate (Tween 20), polyethylene glycol sorbitan monopalmitate (tween 40), polyethylene glycol sorbitan monooleate (Tween 80), polyvinyl alcohol (PVA), and poly(ethoxy)nonyl phenol, ethylene maleic anhydride (EMA) copolymer, Easy-Sperse™ (from ISP Technologies Inc.), ionic surfactants such as partially neutralized salts of polyacrylic acids such as sodium or potassium polyacrylate or sodium or potassium polymethacrylate. Brij™-35, Hypermer™ A 60, or sodium lignosulphate, and mixtures thereof.

Emulsifiers may also include, but are not limited to, acrylic acid-alkyl acrylate copolymer, poly(acrylic acid), polyoxyalkylene sorbitan fatty esters, polyalkylene co-carboxy anhydrides, polyalkylene co-maleic anhydrides, poly(methyl vinyl ether-co-maleic anhydride), poly(propylene-co-maleic anhydride), poly(butadiene co-maleic anhydride), and polyvinyl acetate-co-maleic anhydride), polyvinyl alcohols, polyalkylene glycols, polyoxyalkylene glycols, and mixtures thereof. Preferred emulsifying agents are fatty alcohol exthoylates (particularly of the Brij^TI class), salts of ether sulphates (including SLES), alkyl and alkaryl sulphonates and sulphates (including LAS and SDS) and cationic quaternary salts (including CTAC and CTAB).

The nature of the emulsifying agent can be selected to ensure that the finished particle is compatible with the environment in which it will be used. In particular cores which are formed in the presence of anionic surfactant systems (for example SLES 1 -4 EO, preferably 1 -3 EO and the others mentioned above) are compatible with products in which the environment comprises an anionic surfactant, such as, for example body-wash products and shampoos. Cores which are formed in the presence of cationic surfactant (for example a cationic quaternary salt as mentioned above and in particular one of the alkyl trimethyl ammonium halides) are compatible with products in which the environment comprises a cationic surfactant, for example a hair conditioner.

It is particularly preferred that the emulsifying agent further comprises a nonionic surfactant. This is believed to produce a particle which deposits better on skin or hair than one produced solely with a charged surfactant emulsifier. It is also preferred that the non-ionic surfactant is hydrophilic, so as to promote the formation of a stable mini-emulsion. The alcohol ethoxylates with more than ten moles of ethoxylation, for example Synperonic A20 (C1320EO), yield good results. DLS data for samples shows that as the level of surfactant increases the particle size becomes smaller, which is also advantageous. Preferably, the ratio of non-ionic to anionic emulsifier should be greater than 1 :1 (i.e. non-ionic is present in excess) and the total surfactant level should be >3%wt of the polymerisation mixture. Co-surfactant:

Typically a co-surfactant will be present in the dispersed phase and in the resulting particle. Suitable co-surfactants for use in the present invention include hexadecane, cetyl alcohol, lauroyl peroxide, n-dodecyl mercaptan, dodecyl methacrylate, stearyl methacrylate, polystyrene, polydecene, mineral oils, isopropyl myristate C13-C15 alkyl benzoate and polymethyl methacrylate.

The preferred cosurfactants comprise hexadecane, polydecene and isopropyl myristate.

As a wt% of oil phase as a total, the co-surfactant is typically 0-20%, preferably 1 -15%, more pref 2-12.5%. Catalyst

Optional catalyst may be present in the dispersed phase of the emulsion. This advantageously minimises the hydrolysis of isocyanate to primary amine, which can react with further isocyanate to form polyurea. This unwanted reaction can result in an excess of diol being left at the end of the process which can potentially lead to the formation of malodour and interfere with cross-linking reactions.

Suitable catalysts may comprise amino or organo-metalic compounds such as N,N'-dimethylaminoethanol, Ν,Ν'-dimethylcyclohexylamine, bis-(2- dimethylaminoethyl) ether, Ν,Ν'-dimethylacetylamine, diaminobicyclooctane, stannous octoate and dibutyl tin dilaurate, 1 ,3-bis(dimethylamino) butane, pentamethyldiethylenetriamine and mixtures thereof.

The level of catalyst is typically 0.1 -2%with respect to chain-growth monomer. Polymerisation Conditions

As noted above, polymerisation typically occurs in at least two phases. In one method in the earlier phase the shell is preferably formed by a reaction which, in preferred embodiments occurs at less than about 60 Celsius, typically 15-55 Celsius. In the later phase the inner region is polymerised at a preferred temperature of more than about 70 Celcius, typically 70-95 Celcius.

Both reactions are allowed to proceed for sufficiently long for polymerisation to be essentially complete, 1 -3 hours being typical for each stage.

Deposition aid may added at the end of the later phase (preferably after cooling), when for example, further shell forming material (for example further isocyanate and co-momomer) are also added to bind the deposition aid to the outer surface of the particle by the formation of further shell material which entraps a portion of the deposition aid and leads to a "hairy" particle in which the "hair" comprises the deposition aid.

For simple core-shell particles, the core excluding benefit agent is less than or equal to 80%wt of mass, and the shell generally 20%wt or greater of the mass of the particle.

Preferably the emulsion polymerisation step is a so-called "mini-emulsion" polymerisation, performed with a dispersed phase droplet size of below one micron. Sufficiently fine emulsions can be obtained by a range of methods, including sonication, and/or via high shear dynamic mixers or static mixers. Mini- emulsion products have excellent suspending properties. Formaldehvde Scavenger:

Compositions including the particles of present invention can comprise (if required) a formaldehyde scavenger. The formaldehyde scavengers disclosed in EP 1797947 can be used in embodiments of the invention. In the alternative a formaldehyde scavenger can be added at the end of polymerisation to the aqueous phase of the reaction mixture.

The formaldehyde scavengers of the present invention are preferably selected from beta-dicarbonyl compounds, mono- or di-amide materials, amines and other materials which can react with formaldehyde and remove it.

Suitable beta-dicarbonyl compounds of the present have an acidic hydrogen giving rise to a nucleophilic attack on formaldehyde.

Preferred beta-dicarbonyl compounds are acetoacetamide (BKB (available in the marketplace from Eastman)), ethyl acetoacetate (EAA (available in the

marketplace from Eastman)), Ν,Ν-Dimethyleneacetamide (DMAA (available in the marketplace from Eastman)), acetoacetone, dimethyl-1 ,3-acetonedicarboxylate, 1 ,3-acetonedicarboxylic acid, malonic acid, resorcinol, 1 ,3-cyclohexadione, barbituric acid, 5,5-dimethyl-1 ,3-cyclohexanedione (dimedone), 2,2-dimethyl-1 ,3- dioxane-4,6-dione (Meldrum's acid), salicylic acid, methyl acetoacetate (MAA (available in the marketplace from Eastman)), ethyl-2-methyl acetoacetate, 3-methyl-acetoacetone, dimethyl malonate, diethyl malonate, 1 ,3-dimethyl barbituric acid, resorcinol, phloroglucinol, orcinol, 2,4-dihydroxy benzoic acid, 3,5- dihydroxy benzoic acid, and malonamide. Other suitable beta-dicarbonyl scavenger are listed in U.S. 5,194,674 and 5,446,195 as well as in Tomasino et al, Textile Chemist and Colorist, vol. 16, No. 12 (1984),

Mono or Di-amides may also be used as effective formaldehyde scavengers. Examples of the preferred effective mono- and di-amide scavengers are urea, ethylene urea, propylene urea, caprolactam, glycouril, hydantoin, 2-oxazolidinone, 2-pyrrolidinone, uracil, barbituric acid, thymine, uric acid, allantoin, polyamides, 4,5-dihydroxyethylene urea, monomethylol-4-hydroxy-4-methoxy-5,5-dimethyl- propylurea, nylon 2-hydroxyethyl ethylene urea (SR-51 1 ; SR-512 (Sartomer)), 2-hydroxyethyl urea (Hydrovance (National Starch)), L-citrulline, biotin, N-methyl urea, N-ethyl urea, N-butyl urea, N-phenyl urea, 4,5-dimethoxy ethylene urea and succinimide. Another class of compounds that are effective formaldehyde scavengers are amines which form imines by reaction with formaldehyde.

Preferred amines include, polyvinyl amine) (Lupamin™ (BASF)), arginine, lysine, asparagines, proline, tryptophan, 2-amino-2-methyl-1 -propanol (AMP); proteins such as casein, gelatin, collagen, whey protein, soy protein, and albumin;

melamine, benzoguanamine, 4-aminobenzoic acid (PABA), 3-aminobenzoic acid, 2-aminobenzoic acid (anthranilic acid), 2-aminophenol, 3-aminophenol,

4-aminophenol, creatine, 4-aminosalicylic acid, 5-aminosalicylic acid, methyl anthranilate, methoxylamine HCI, anthranilamide, 4-aminobenzamide, p-toluidine, p-anisidine, sulfanilic acid, sulfanilamide, methyl-4-aminobenzoate, ethyl-4- aminobenzoate (benzocain), beta-diethylaminoethyl-4-aminobenzoate (procain), 4-aminobenzamide, 3,5-diaminobenzoic acid and 2,4-diaminophenol.

Other amines as disclosed in copending U.S. Letters for Patent Application Number 1 1/123,898 and U.S. 6,261 ,483, and in Tomasino et al, Textile Chemist and Colorist, vol. 16, No. 12 (1984).

Other formaldehyde scavengers are known, for example, hydrazines such as 2,4- dinitrophenzylhydrazine react with formaldehyde to give hydrazones. The reaction is pH-dependent and reversible. Other preferred amines can be selected from a non-limiting list of 1 ,2-phenylenediamine, 1 ,3-phenylenediamine, and 1 ,4- phenylenediamine.

In addition, aromatic amines, triamines, and aliphatic polyamine may also be used. Examples of these amines may include, but are not limited to, aniline, hexamethylene-diamine, bis-hexamethylenetriamine, triethyl-aminetriamine, poly(propyleneoxide) triamine, and poly(propyleneglycol)-diamines.

The formaldehyde scavengers of WO 2007/091223 may also be used in

embodiments of the invention. These are sodium bisulfite, urea, cysteine, cysteamine, lysine, glycine, serine, carnosine, histidine, glutathione,

3,4- diaminobenzoic acid, allantoin, glycouril, anthranilic acid, methyl anthranilate, methyl 4- aminobenzoate, ethyl acetoacetate, acetoacetamide, malonamide, ascorbic acid, 1 ,3- dihydroxyacetone dimer, biuret, oxamide, benzo-guanamine, pyroglutamic acid, pyrogallol, methyl gallate, ethyl gallate, propyl gallate, triethanol amine, succinamide, thiabendazole, benzotriazol, triazole, indoline, sulfanilic acid, oxamide, sorbitol, glucose, cellulose, polyvinyl alcohol), polyvinyl amine), hexane diol, ethylenediamine-N,N'-bisacetoacetamide, N-(2- ethylhexyl)acetoacetamide, N-(3-phenylpropyl) acetoacetamide, lilial, helional, melonal, triplal, 5,5-dimethyl- l,3-cyclohexanedione, 2,4-dimethyl-3-cyclohexenecarboxaldehyde, 2,2-dimethyl- l,3-dioxan-4,6-dione, 2-pentanone, dibutyl amine, triethylenetetramine,

benzylamine, hydroxycitronellol, cyclohexanone, 2-butanone, pentane dione, dehydroacetic acid, chitosan, and/or mixtures thereof. Particularly preferred scavengers comprise at least one of urea, ethylene urea, ethylacetamide, acetoacetamide and mixtures thereof. The most preferred scavengers are selected from the group consisting of urea, ethylene urea, ethylacetamide, acetoacetamide and mixtures thereof. Use in Products

The end-product, personal care compositions of the invention may be in any physical form e.g., a solid bar, a paste, gel or liquid, especially, an aqueous-based liquid. They are intended for direct application to the desired substrate, preferably skin and hair. In the context of the present invention, the term "personal care composition" is intended to exclude laundry compositions, hard surface

compositions, such as household cleaners, dish wash detergents, etc. The particles of the invention may be advantageously incorporated into surfactant- containing compositions. The particles are included in said compositions at levels of from 0.001 wt % to 10 wt %, preferably from 0.001 wt % to 9 wt %, more preferably from 0.005 wt % to 7.55 wt %, most preferably from 0.01 wt % to 5 wt % by weight of the total composition.

Formulated compositions comprising the particles of the invention may contain a surface-active compound (surfactant) which may be chosen from soap and non soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface active compounds and mixtures thereof, preferably selected from cationic, non-ionic, amphoteric and zwitterionic surface active compounds and mixtures thereof.

Many suitable surface active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. The preferred surface-active compounds that can be used are soaps and synthetic non soap anionic, and non-ionic compounds.

Suitable anionic surfactants are well-known to those skilled in the art. Examples include primary and secondary alkyl sulphates, particularly C8 to C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyi sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

Compositions may also comprise a cationic polymer. The cationic polymer may be a homopolymer or be formed from two or more types of monomers. The molecular weight of the polymer will generally be between 5 000 and 10 000 000, typically at least 10 000 and preferably in the range 100 000 to about 2 000 000. The polymers will have cationic nitrogen containing groups such as quaternary ammonium or protonated amino groups, or a mixture thereof.

The cationic charge density of the cationic polymer is suitably at least 0.1 meq/g, preferably above 0.8 or higher. The cationic charge density should typically not exceed 3 meq/g. It is preferably less than 2 meq/g. The charge density can be measured using the Kjeldahl method and should be within the above limits at the desired pH of use, which will in general be from about 3 to 9 and preferably between 4 and 8.

The cationic nitrogen-containing group will generally be present as a substituent on a fraction of the total monomer units of the cationic polymer. Thus when the polymer is not a homopolymer it can contain spacer non-cationic monomer units. Such polymers are described in the CTFA Cosmetic Ingredient Directory, 3rd edition. The ratio of the cationic to non-cationic monomer units is selected to give a polymer having a cationic charge density in the required range.

Suitable cationic polymers include, for example, copolymers of vinyl monomers having cationic amine or quaternary ammonium functionalities with water soluble spacer monomers such as (meth)acrylamide, alkyi and dialkyi (meth)acrylamides, alkyi (meth)acrylate, vinyl caprolactone and vinyl pyrrolidine. The alkyi and dialkyi substituted monomers preferably have C1 -C7 alkyi groups, more preferably C1 -3 alkyl groups. Other suitable spacers include vinyl esters, vinyl alcohol, maleic anhydride, propylene glycol and ethylene glycol.

The cationic amines can be primary, secondary or tertiary amines, depending upon the particular species and the pH of the composition. In general secondary and tertiary amines, especially tertiary, are preferred.

Amine substituted vinyl monomers and amines can be polymerized in the amine form and then converted to ammonium by quaternization.

The cationic polymers can comprise mixtures of monomer units derived from amine- and/or quaternary ammonium-substituted monomer and/or compatible spacer monomers.

Suitable cationic polymers include, for example: copolymers of 1 -vinyl-2-pyrrolidine and 1 -vinyl-3-methyl-imidazolium salt (e.g. chloride salt), referred to in the industry by the Cosmetic, Toiletry, and Fragrance Association, (CTFA) as Polyquaternium-16. This material is commercially available from BASF Wyandotte Corp. (Parsippany, NJ, USA) under the LUVIQUAT tradename (e.g. LUVIQUAT FC 370); copolymers of 1 -vinyl-2-pyrrolidine and dimethylaminoethyl methacrylate, referred to in the industry (CTFA) as Polyquaternium-1 1 . This material is available commercially from Gaf Corporation (Wayne, NJ, USA) under the GAFQUAT tradename (e.g., GAFQUAT 755N); cationic diallyl quaternary ammonium-containing polymers including, for example, dimethyldiallyammonium chloride homopolymer and copolymers of acrylamide and dimethyldiallylammoniunn chloride, referred to in the industry (CTFA) as Polyquaternium 6 and Polyquaternium 7, respectively; mineral acid salts of amino-alkyl esters of homo-and co-polymers of unsaturated carboxylic acids having from 3 to 5 carbon atoms, (as described in U.S. Patent 4,009,256); cationic polyacrylamides(as described in WO95/2231 1 ).

Other cationic polymers that can be used include cationic polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives.

Cationic polysaccharide polymers suitable for use in compositions of the invention include those of the formula:

A-O-[R-N⁺(R¹)(R²)(R³)X^"] , wherein: A is an anhydroglucose residual group, such as a starch or cellulose anhydroglucose residual. R is an alkylene, oxyalkylene, polyoxyalkylene, or hydroxyalkylene group, or combination thereof. R¹, R² and R³ independently represent alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, or alkoxyaryl groups, each group containing up to about 18 carbon atoms. The total number of carbon atoms for each cationic moiety (i.e., the sum of carbon atoms in R¹, R² and R³) is preferably about 20 or less, and X is an anionic counterion.

Cationic cellulose is available from Amerchol Corp. (Edison, NJ, USA) in their Polymer JR (trade mark) and LR (trade mark) series of polymers, as salts of hydroxyethyl cellulose reacted with trimethyl ammonium substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 10. Another type of cationic cellulose includes the polymeric quaternary ammonium salts of hydroxyethyl cellulose reacted with lauryl dimethyl ammonium-substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 24. These materials are available from Amerchol Corp. (Edison, NJ, USA) under the tradename Polymer LM-200.

Other suitable cationic polysaccharide polymers include quaternary nitrogen- containing cellulose ethers (e.g. as described in U.S. Patent 3,962,418), and copolymers of etherified cellulose and starch (e.g. as described in

U.S. Patent 3,958,581 ).

A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic guar gum derivative, such as guar hydroxypropyltrimonium chloride

(Commercially available from Rhone-Poulenc in their JAGUAR trademark series).

Examples are JAGUAR C13S, which has a low degree of substitution of the cationic groups and high viscosity. JAGUAR C15, having a moderate degree of substitution and a low viscosity, JAGUAR C17 (high degree of substitution, high viscosity), JAGUAR C16, which is a hydroxypropylated cationic guar derivative containing a low level of substituent groups as well as cationic quaternary ammonium groups, and JAGUAR 162 which is a high transparency, medium viscosity guar having a low degree of substitution.

Preferably the cationic polymer is selected from cationic cellulose and cationic guar derivatives. Particularly preferred cationic polymers are JAGUAR C13S, JAGUAR C15, JAGUAR C17 and JAGUAR C16 and JAGUAR C162.

The cationic polymer will generally be present in compositions of the invention at levels of from 0.01 to 5%, preferably from about 0.05 to 1 %, more preferably from about 0.08% to about 0.5% by weight. Compositions may also contain non-ionic surfactant. Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8 to C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C10 to CI5 primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and

polyhydroxyamides (glucamide). It is preferred if the level of non-ionic surfactant is from 0 wt% to 30 wt%, preferably from 1 wt% to 25 wt%, most preferably from 2 wt% to 15 wt%, by weight of a fully formulated composition comprising the particles of the invention.

In order that the present invention may be still further understood and carried forth into practice it will be further described with reference to the following examples:

EXAMPLES

Unless a specific protocol is provided the following protocols are followed: using a controlled flow and temperature sink. SLES solution is at 14% (to base wash the hair, if not already pre-washed). The base shampoo for conditioner treatment: 12% SLES/1 .6% CAPB + Salt + Glydant.

Base Washing of Hair Switches

Always wear gloves when washing switches and change in-between treatments. Wet the 4 switches under running water (35-40°C, flow rate of 4L/min). Remove the excess water by running thumb and forefinger along the length of the switches. Dip all 4 switches in the SLES solution and remove the excess again by running thumb and forefinger along the length of the switches. Massage for 30 seconds while holding the ends of the switches to avoid tangling (halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches). Rinse under the warm running water for 30 seconds (halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches. Remove the excess again by running thumb and forefinger along the length of the switches. Repeat the SLES treatment steps. Rinse for 1 minute (during which take the front 2 switches and place to the back of the 4 switches). The excess water is removed again by running thumb and forefinger along the length of the switches.

Shampoo Treatment - only Shampoo Treatment of Hair Switches Always wear gloves when washing switches and change in-between treatments. Measure 2ml of test shampoo into a 2ml disposable syringe. Wipe residue off the bottom of the syringe to gain a more accurate weight. Place the Petri dish containing the shampoo filled syringe onto a balance and set to zero. Dispense 2ml of shampoo along the length of the switch. Place the syringe back on the balance and note the weight of shampoo used. Massage the switches for 30 seconds while holding the ends of the switches to avoid tangling. Note: halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches. Rinse for 30 seconds. Avoid touching the switches too much while rinsing. Note: halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches. Remove the excess water again by running thumb and forefinger along the length of the switches. Place the 4 damp switches in a glass jar (no drying). Shampoo and Conditioner Treatment of Hair Switches

Always wear gloves when washing switches and change in-between treatments. Measure 2ml of base shampoo into a 2ml disposable syringe. Dispense the 2ml of base shampoo along the length of the switch. Massage the switches for 30 seconds while holding the ends of the switches to avoid tangling. Note: halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches. Rinse for 30 seconds. Avoid touching the switches too much while rinsing. Note: halfway through the 30s, take the front 2 switches and place them to the back of the 4 switches. Remove the excess water again by running thumb and forefinger along the length of the switches.

Weight 4g of conditioner with a 5ml_ disposable syringe (-equivalent to 4.1 ml_). Wipe residue off the bottom of the syringe to gain a more accurate weight. Place the Petri dish containing the syringe of conditioner on a balance and set to zero. Dispense the 4g of conditioner along the length of the switch. Place the syringe back on the balance and note the weight of conditioner used. Massage the switches for 1 minute. Note: after 30s, take the front 2 switches and place them to the back of the 4 switches. Rinse for 1 minute. Avoid touching the switches too much while rinsing. Note: after 30s, take the front 2 switches and place them to the back of the 4 switches. Remove the excess water by running thumb and forefinger along the length of the switches. Place the 4 damp switches in a glass jar (no drying). Example 1 - Synthesis of Core using Anionic Surfactant System

A surfactant stock solution was prepared by dissolving 0.75 g SLES-1 EO

(Texapon N701 - Clariant) in 50 ml demin water. 1 g of hexadecane and 20 g of butyl methacrylate monomer were weighed into a 125 ml glass jar. To this 8 g of surfactant stock solution and 66.5 g demineralised water were added and the mixture gently shake to form a crude emulsion. Using a sonic probe (Branson Digital Sonfier 450D), the crude emulsion was sonicated at 60 % amplitude for 1 .5 mins, the jar resealed, shaken and sonicated at 60% amplitude for a further 1 .5 mins. The miniemulsion was charged to a 250 ml_ 2-neck round bottom flask fitted with a condenser and an overhead stirrer and heated to 85°C. Once the miniemulsion had reached the desired temperature the initiation system (0.2 g Sodium bicarbonate in 2 ml_ water plus 0.2 g ammonium persulphate in 2 ml_ water) was added over a two minute period and the reaction left to polymerise for 3 hours. Subsequently, the reaction was cooled and filtered through

BioPrepNylon synthetic cheesecloth (50 μιτι). The reaction vessel and stirrer were checked for signs of coagulation and grit formation. Final solids content was determined by gravimetric analysis and the particle size determined by dynamic light scattering. (20.2 % solids and 166 nm particle size.) Example 2 - Synthesis of Core using cationic Surfactant System

A surfactant solution was prepared by dissolving 3 g Synperonic A20 (Uniqema) and 1 g cetyl trimethylammonium bromide in 364 ml demin water. 10 g of hexadecane, 100 g of butyl methacrylate monomer were weighed into a 500 ml glass jar. The mixture was gently shake to form a crude emulsion. Using a sonic probe (Branson Digital Sonfier 450D), ultrasonicate the crude emulsion at 50 % amplitude for 5 mins, seal and shake the jar and ) ultrasonicate the emulsion at 50 % amplitude for a further 5 mins. Transfer the miniemulsion into a 1000 ml_ 3-neck round bottom flask fitted with a condenser and an overhead stirrer and heated to 80 °C. Once the miniemulsion has reached the desired temperature the first part of the initiation system is added (4 g ascorbic acid in 20 ml_ water. The second part of the initiation system (4ml tert-butyl hydroperoxide solution, 50 %, Fluka) was added via dropwise over a 45 minute period. Once the addition has finished stir the reaction for 90 minutes. Subsequently allow the reaction to cool, and transfer to a jar. The reaction vessel and stirrer should be checked for signs of coagulation and grit formation. Final solids content was determined by gravimetric analysis and the particle size determined by dynamic light scattering. (22.2 % solids and 145 nm particle size.) Example 3 - Addition of polymeric shell to anionic particle

500 g miniemulsion prepared via example 1 was transferred to a 1 L 3-neck reaction flask fitted with an overhead stirrer and condenser. The emulsion was heated to 80°C with stirring at 300 rpm. Initiator solutions were prepared by dissolving 0.225 g ammonium persulfate in 2 ml water and 0.225 g sodium bicarbonate in 4 ml water and added via pipette. The shell monomer, 15 g methyl methacrylate, was added dropwise via syringe pump over the course of 60 minutes. After complete monomer addition, the reaction was stirred for a further 1 .5 hours. 0.075 g Ascorbic acid in 2 ml_ water and 0.075 g t-butylhydroperoxide were added subsequently, and the reaction allowed to stir for a further 30 minutes after which, the reaction was cooled to room temperature and filtered through BioPrepNylon synthetic cheesecloth (50 μιτι). The reaction vessel and stirrer were checked for signs of coagulation and grit formation. Final solids content was determined by gravimetric analysis and the particle size determined by dynamic light scattering. (21 .6 % solids and 195 nm particle size.)

Example 4 - Addition of polymeric shell to cationic particle

Weigh 300 g miniemulsion from example 2 into a 500 ml 3-neck reaction flask fitted with an overhead stirrer and condenser. Dissolve 0.15 g ascorbic acid in 1 .5 ml water. Heat the emulsion to 80°C, stir at 250 rpm and add the ascorbic acid solution via pipette. The shell monomer, 8 g methyl methacrylate and initiator tert-butyl hydroperoxide, 0.15 ml (50 %, Fluka) were combined in a vial then.

Feed the shell monomer and initiator mixture, via syringe pump over a 60 minute period. After complete monomer addition stir for a further hour. Add tert-butyl hydroperoxide solution (0.1 ml) and ascorbic acid (0.1 g) in 1 ml water via pipette and stir for a further hour. Subsequently allow the reaction to cool, and transfer to a jar. The reaction vessel and stirrer should be checked for signs of coagulation and grit formation. Final solids content was determined by gravimetric analysis and the particle size determined by dynamic light scattering. (23.6 % solids and 161 nm particle size.)

Example 5 - Addition of deposition aid to core shell particle.

Weigh 150 g miniemulsion from example 3 or 4 into a 500 ml 3-neck reaction flask fitted with an overhead stirrer and condenser. Dissolve 0.5 g polysaccharide (eg. Locust bean gum) in 49.5 ml boiling water using a IKA T25 homogenizer at 12,000 rpm for 2 minutes. Add 32 g polysaccharide solution to the 500 ml flask and heat the emulsion to 75°C and stir for 30 minutes at 250 rpm. Dissolve 0.18 g ascorbic acid in 2 ml water and add via pipette and then add methyl acrylate (1 .7 ml) followed by 30 % hydrogen peroxide (0.45 ml) and stir for 2 hours. Add 30 % hydrogen peroxide solution (0.1 ml) and ascorbic acid (0.04 g) in 0.5 ml water and stir for a further two hours. Subsequently allow the reaction to cool, and transfer to a jar. The reaction vessel and stirrer should be checked for signs of

coagulation and grit formation. Final solids content was determined by

gravimetric analysis and the particle size determined by dynamic light scattering. (19.6 % solids and 223 nm particle size.)

Example 6 - Formulation of a hair conditioner

Deionised water (302.50g) and lactic acid (1 .45g) were mixed with an low speed mixer and heated to 85°C. TAS (5.00g), BTAC (5.00g) and stearyl alcohol (20.00g) were added with sequentially and allowed to become molten. The mixture was then removed from the hotplate, transferred to a high shear mixer and mixed for 5 minutes.

The Mixture was then returned to the low speed mixer and deionised water (20.00g) was added. When the temperature reduced to 50°C a solution of KCI (0.40g) & EDTA (0.40g) in Deionised water (12.00g)) was added. At 40°C the Miniemulsion suspension (16.00g) was added dropwise. When the temperature fell below 30°C preservatives (Methylchloroisothaizolinone Methylisothiazolinone (0.16g) and DMDM Hydantoin (0.40g)) and Perfume (2.40g) were added and the mixture allowed to stir for a further 10 minutes.

The conditioner was allowed to equilibrate for a week and then DC7134 silicone emulsion (14.29g) was added and mixed thoroughly.

Example 7 - Formulation of a Body Wash.

4 g Aqua SF-1 (Lubrizol) was weighed into a 125 mL jar, and 74.85 g water and 10 g miniemulsion polymer slurry was added sequentially. The mixture was agitated until homogeneous then added to 15.74 g SLES-1 EO (Clariant -

Texapon N701 ) pre-weighed into a 250 mL beaker, and stirred using an overhead stirrer until homogeneous. 0.05 g Kathon-CG, 3.36 g CAPB (Evonik - Tegobetain) and 1 g NaCI were then added sequentially with continued stirring. The pH was adjusted to 5.5 using 10% sodium hydroxide solution. 1 g Perfume or 1 g water was then added with further stirring then transferred to a storage jar.

Example 8 - Formulation of a Shampoo

72.14 g water was weighed into a 125 mL jar, and 4 g miniemulsion polymer slurry was added. The mixture was agitated until homogeneous then added to 17.14 g SLES-1 EO (Clariant - Texapon N701 ) pre-weighed into a 250 ml_ beaker, and stirred using an overhead stirrer until homogeneous. 0.05 g Kathon-CG, 0.09 g Glydanty and 5.33 g CAPB (Evonik - Tegobetain) and 0.5 g NaCI were then added sequentially with continued stirring. The pH was adjusted to 5.5 using 10% sodium hydroxide solution. 0.75 g Perfume was then added with further stirring then transferred to a storage jar. Example 9 - Perfume Panel Assessment

The following protocol was used to assess perfume intensity when delivering fragrance from a hair conditioner, with and without polymer perfume particles. Prior to application of the test product 7gram / 10inch long DBE (Dark Brown European) switches are soaked in 14% SLES solution. Each switch is rinsed individually under running water (35-40°C, flow rate of 4L/min). The excess water removed and the switch detangled using a matador comb. Using a non

hypodermic syringe the test product is applied to the hair. The switch is lathered with a rubbing motion for 60 seconds; the excess lather removed and rinsed under running water for 60 seconds (35-40°C, flow rate of 4L/min).

The samples are evaluated in triplicate by a Naive panel. The test is been run as a simple paired comparison test i.e. free fragrance sample vs. sample which contains polymer particles.

The hair switches are assessed at a range of time points

• Fresh - immediately after application

• 2hrs after application

· 4hrs after application

• Next Day Pre and Post comb (comb three time using the narrow end of the comb)

The number of panellists used in each test is 13-15. Panellists are asked to pick the sample with the greatest fragrance intensity at the measurement point.

Two hair conditioner formulations were prepared, both contained 0.6wt%

fragrance. One sample contained 1wt% polymer particles and the second sample contained no polymer particles. The results from the preference panel are outlined in the table below. % Votes (Sample % Votes (sample

Sample including polymer with no polymer

particle ) particle)

Fresh 57.78 42.22

2 hrs 68.89 31 .1 1

4 hrs 82.22 17.78

24 hrs 80.00 20.00

25 hrs/ combed 80.00 20.00

Example 10 - Perfume measurement from Shampoo on hair switches using GC A shampoo formulation was prepared as outlines in example 8. A series of hair switches were prepared as described in the standard protocol. Perfume was extracted at various time points using the extraction procedure outlined and quantified via GC. The GC method is as outlined below. The level of perfume extracted at various time points is detailed below.

par c e, ry Example 1 1 - Perfume measurement from Conditioner on hair switches using GC

A conditioner formulation was prepared as outlines in example 6. A series of hair switches were prepared as described in the standard protocol. Perfume was extracted at various time points using the extraction procedure outlined, and quantified via GC. The GC method is as outlined below. The level of perfume extracted at various time points is detailed below.

Example 12 - Perfume absorption in a bodywash liquid

A bodywash formulation was prepared as outlined in example 7. A headspace GC measurement was used to determine the level of perfume absorbed from the bodywash formulation into the polymer particles.

The chromatographic conditions used were as follows. An Agilent HP5 column (30 m length, 0.32 mm diameter, 0.25 micron film thickness) was used for the chromatographic separation of the components. The SPME fibre assembly of 23-Gauge, 50/30 microns, DVB/CAR/PDMS was used for the extraction of the analytes from the sample headspace. The sample was agitated in an agitator at 35°C for 20 minutes, and then the headspace above the sample was sampled using the SPME fibre.

The injection port was setup in splitless mode and held at a temperature of 270°C. The carrier gas employed for the system was helium and the flow rate was set at 1 .7mL/min. The column was initially heated to 40°C then heated to 200°C at a rate of 5°C per minute, then at 100°C per minute to 280°C and held for 3 minutes. The total run time was 35.8 minutes. The mass spec detector was set with a gain factor of 1 resulting in an EM voltage of 1 153V. Scan parameters were set at a low mass of 33 and a high mass of 300. The source temperature was held at 230°C and the quad at 130°C. Injection volume of extracted sample was 1 microlitre. The system was first calibrated across an appropriate range before conducting analysis on the extracted samples. The following table outlines the quantities of a selection of fragrance notes absorbed from the bodywash base into the polymer particles.

Perfume Note % Fragrance absorbed % Fragrance absorbed

at 0.5% perfume in at 1 .0% perfume in

formulation. formulation.

Manzanate 28.6 23.4

Octanal 34.8 30.3

Tetrahydrolinalool 19.4 1 1 .2

Linalyl acetate 43.8 28.6

Benzyl acetate 36.0 14.3

Delta damascone 55.2 27.4

OTBCHA-1 24.7 25.5

OTBCHA-2 34.3 25.6

Verdyl acetate 32.6 15.8 Example 13 - Extended perfume release from Skin via PTR-MS

A bodywash formulation was prepared as outlined previously. A 3cm x 6cm piece of woven cotton fabric was washed with 0.5ml_ sample in following conditions: Water temp is controlled at £5C and flow rate is controlled at 3-4 L/ min. Prior to treatment with body wash sample, cotton is rinsed for 30 seconds prior to treatment. 0.5 g of body wash sample is dosed onto wet cotton, lathered with gloved forefinger for 30 seconds, rinsed for 15 seconds. Treated cotton is then patted dry between a folded paper towel for 10 pats. PTR-MS at eight m/z values 37, 81 (corresponding to limonene and other terpenes), 89, 91 , 95, 103 and 137, was found to be sensitive to components in the bodywash formulation. On placing the cloth in the flask and starting the measurement, the PTR-MS signal at all these selected masses rose to a maximum at about 3.5 minutes. The signals at some m/z values (81 , 95 and 137) show that for some components of the fragrance, the particle provides a prolonged release benefit. Thus for these m/z values, the signal when the cloth has been in the flow of air for a short time of 3.5 minutes was higher for the free fragrance than for the body wash containing polymer particles for some of the signals. At an intermediate time of about 34 minutes the intensity was about the same for the free fragrance and the body wash containing polymer particles. At longer times, between 50 and 140 minutes, and especially between 45 minutes and 1 hour and 40 minutes, the PTR-MS signal is higher in the case of the bodywash containing the polymer particles.

PTR-MS Signal Intensity (Arbitrary Units)

Bodywash without polymer particles Bodywash with polymer particles

Time m/z m/z m/z = m/z = m/z = m/z m/z m/z m/z = m/z =

(minutes) =37 =81 91 95 137 =37 =81 = 91 95 137

3.5 23664 33082 121 1 3435 7348 22918 18099 1098 1884 4124

34.0 22373 8176 950 820 1920 22660 8564 950 899 1978

49.0 22393 4929 898 487 1 174 22259 8258 914 830 1906

64.0 22239 2986 786 283 772 22026 7048 858 740 1643

78.3 22344 1903 737 179 501 22517 5998 807 590 1420

93.9 22470 1389 669 107 358 22019 4373 792 431 1039 Extraction procedure for GC Analysis

Perfume extraction from hair switches was conducted using a Gerhardt Soxtherm extractor S 306 A.

Add to a Soxtherm thimble four 5g / l Oinch Dark brow European hair switches. Place the thimble in a Soxtherm glass beaker. Add 150 ml of 50:50

acetone/pentane to the Soxtherm beaker and add some boiling stones. Start the extraction procedure and use the method as outlined below.

Hotplate : 150°C

Boiling time : 45 min

Solvent reduction A : 3 x 15 ml

Extraction time : 45 min

Solvent reduction B : 0 min

Solvent reduction C : 0 min

Solvent interval : 4 min

Solvent reduction pulse : 3 sec Add 5.0 ml of the internal standard solution to the beaker (100 mg methyl decanoate dissolved in 100 ml of acetone). The total extracts were collected and used for GC analysis.

GC method for perfume measurement after extraction from hair.

An Agilent GC 6890N fitted with an FID detector and a MSD 5975 mass spec detector was used for perfume quantification. The GC was fitted with an Agilent HP-1 polydimethylsiloxane capillary GC column. The injection port was heated to 250°C and was of split configuration with a ratio of 20:1 and a total gas flow of 20mL/min. The initial column temperature was 70°C, this was heated at 2°C per minute to 250°C and held for forty minutes giving a total run time of 130 minutes. The column carrier gas used was nitrogen and flow rate was set at 0.8mL/min. The FID detector was set at 300°C with a hydrogen flow rate of 40mL/min, an air flow rate of 450mL/min and carrier gas flow rate of 30mL/min. The mass spec detector was set with a gain factor of 1 resulting in an EM voltage of 1 153V. Scan parameters were set at a low mass of 33 and a high mass of 300. The source temperature was held at 230°C and the quad at 130°C. The system was first calibrated across an appropriate range before conducting analysis on the extracted samples. The analysis result is expressed as milligrams of perfume per gram of hair.

Claims

1 . A personal care composition for direct application to a surface selected from human skin and/or hair, including from 0.001 wt % to 10 wt %, preferably from 0.0001 wt % to 9 wt %, by weight of the total composition, of a core- shell benefit agent carrier particle comprising: a) a core, optionally comprising a benefit agent;

b) at least one polymer shell surrounding the core,

c) a deposition aid, attached to the outer shell and not removed by

exposure to water, said deposition aid comprising at least one polysaccharide selected from the group consisting of poly-mannan, poly-glucan, poly-glucomannan, poly-xyloglucan, poly-galactomannan, dextran, hydroxyl-propyl cellulose, hydroxy-propyl methyl cellulose, hydroxy-ethyl methyl cellulose, hydroxy-propyl guar, hydroxy-ethyl ethyl cellulose or methyl cellulose, with the proviso that the particle is not a particle having an average diameter of less than 50 micron comprising; at least one shell formed by a step-growth polymerisation reaction,

interior to said shell, at least one region formed by chain-growth polymerisation reaction which does not involve an isocyanate, wherein the shell is polymerised prior to the core.

A composition according to claim 1 which is selected from a skin treatment composition, a hair treatment composition, a deodorant and an

antiperspirant, preferably selected from a skin treatment composition and a hair treatment composition.

A composition according to claim 1 or claim 2, which further comprises a cationic polymer.

A composition according to any preceding claim, wherein the core comprises a benefit agent.

A composition according to claim 4, wherein the benefit agent is selected from the group consisting of flavours and fragrances, conditioning agents, sunscreens, colour protection agents, ceramides, antioxidants, dyes, lubricants, unsaturated oils, emollients/moisturiser, insect repellents and antimicrobial agents.

A composition according to any preceding claim that further comprises a surface-active compound selected from soap and non soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface active compounds and mixtures thereof.

A composition according to any preceding claim, which further comprises an additional benefit agent, preferably perfume, which is not encapsulated.

A composition according to any preceding claim, wherein the core-shell benefit agent carrier particle is formed by emulsion polymerisation in the presence of an ionic surfactant.

A hair treatment composition according to claim 8 wherein the ionic surfactant is a cetrimonium-based surfactant.

10. A skin treatment composition according to claim 8 in which the ionic

surfactant is an ethersulphate-based surfactant.