WO2016000912A1

WO2016000912A1 - Benefit agent delivery particle and composition comprising the particle

Info

Publication number: WO2016000912A1
Application number: PCT/EP2015/062753
Authority: WO
Inventors: Christopher Clarkson Jones; Xiaoyun Pan; Haitao QIAN; Yuanyuan Zhang
Original assignee: Unilever NV; Conopco Inc
Current assignee: Unilever NV; Conopco Inc
Priority date: 2014-06-30
Filing date: 2015-06-09
Publication date: 2016-01-07
Anticipated expiration: 2016-12-30

Abstract

Disclosed is a benefit agent delivery particle comprising a core comprising benefit agent, an inner shell; and an outer shell comprising at the outside surface of the particle aromatic compound having dihydroxylphenyl group.

Description

BENEFIT AGENT DELIVERY PARTICLE AND COMPOSITION COMPRISING THE

PARTICLE

FIELD OF THE INVENTION

The present invention relates to a benefit agent delivery particle and composition comprising the particle. In particular, the benefit agent delivery particle comprises a core comprising benefit agent, an inner shell, and an outer shell comprising at the outside surface of the particle aromatic compound having dihydroxylphenyl group.

BACKGROUND OF THE INVENTION

Many home care and personal care products seek to deliver benefit agents to substrates such as textiles, hard surfaces, hair and skin. To achieve a long-lasting benefit agent release performance, encapsulation of the benefit agent in particles has been proposed as a means, in particular for the perfume.

However, when the encapsulating particles are incorporated into product, especially a personal care composition, the deposition efficiency of the encapsulating particles may be affected by the various ingredients in the composition, such as surfactants. The performance for deposition may be a problem, especially on hair, scalp, and/or skin.

We have recognized a need to improve the deposition efficiency of encapsulating particles on hair, scalp, and/or skin when incorporated into a home care or personal care product. Therefore, we developed a benefit agent delivery particle comprising, a core comprising benefit agent, an inner shell, and an outer shell comprising at the outside surface of the particle aromatic compound having dihydroxylphenyl group. It was surprisingly found that when included into a shampoo and/or conditioner, the particles have better deposition onto virgin hair, damaged hair and/or skin. SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a benefit agent delivery particle comprising a core comprising benefit agent, an inner shell, and an outer shell comprising at the outside surface of the particle, aromatic compound having dihydroxylphenyl group.

In a second aspect, the present invention provides a home care or personal case composition comprising at least one particle of the present invention.

In a third aspect, the present invention provides a method of treating a substrate, the method comprising a step of treating the substrate with a composition comprising particle of the present invention. In a fourth aspect, the present invention provides use of particle of the present invention for improved deposition.

All other aspects of the present invention will more readily become apparent upon considering the detailed description and examples which follow.

DETAILED DESCRIPTION OF THE INVENTION

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

All amounts are by weight of the composition, unless otherwise specified.

It should be noted that in specifying any range of values, any particular upper value can be associated with any particular lower value. For the avoidance of doubt, the word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of. In other words, the listed steps or options need not be exhaustive. The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found without multiple dependency or redundancy. "Substantially free of" as used herein refers to less than 3% by weight of the particle unless otherwise stated, preferably less than 1 % by weight, more preferably from 0 to 0.1 % by weight of the particle.

"Particle size" as used herein refers to particle diameter unless otherwise stated. For samples having particulate with diameter no greater than 1 μηη, diameter means the z- average particle size measured, for example, using dynamic light scattering (see international standard ISO 13321 ) with an instrument such as a Zetasizer Nano™ (Malvern Instruments Ltd, UK). For samples having particulate with diameter greater than 1 μηη, diameter means the apparent volume median diameter (D50, also known as x50 or sometimes d(0.5)) of the particles measurable for example, by laser diffraction using a system (such as a Mastersizer™ 2000 available from Malvern Instruments Ltd) meeting the requirements set out in ISO 13320.

Preferably, the particle has an average particle size of 50 nm to 800 μηη, more preferably from 300 nm to 200 μηη, and even more preferably from 0.5 to 100 μηη and most preferably from 1 to 50 μηη.

To have a better deposition on hair, skin and/or scalp, the zeta potential of the particles as measured using a Malvern Nano ZS90 apparatus, in Dl water at a solid content of 50 ppm and pH of 7 at 25°C, is preferably at least -39 mV, more preferably at least -35 mV, even more preferably from -30 to 80mV, and still even more preferably from -24 to 60 mV. Benefit agents according to the present invention refers to agents which may provide a range of benefits to hair, skin and/or fabrics, more preferably to hair and/or skin, even more preferably to hair and/or scalp, and most preferably to hair and/or scalp of human. The benefit agent is typically present in an amount of from 10-90% by total weight of the particle, more preferably from 15 to 60% by total weight of the particle.

Various benefit agents can be incorporated into the particles. Where the end use of the particles is in connection with the preferred surfactant-containing formulations, any compatible benefit agent which can provide a benefit to a substrate which is treated with a preferably surfactant-containing composition can be used. Advantages of the particles of the invention are a good deposition onto skin and/or hair, even in the presence of surfactant.

The benefit agents may include fragrance, pro-fragrance, hair conditioning agent, anti- dandruff agent, moisturizers, emollients, sunscreens, skin lightening agents, anti-aging active, dyes and/or pigments, colour care additives (including dye fixing agents), or a mixture thereof. Preferably, the benefit agent comprises fragrance, pro-fragrance, hair conditioning agent or a mixture thereof. More preferably, the benefit agent comprises fragrance and/or pro-fragrance, and most preferably the benefit agent is fragrance.

Preferably, the core comprises at least 5% of fragrance by weight of the core, more preferably from 10% to 100% by weight of the core, even more preferably from 35% to 100% by weight of the core. Useful components of the fragrance 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 Fragrance 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 fragranced or flavoured, or of modifying the odour and/or taste of said consumer product.

By fragrance 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 fragrance 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.

Another group of fragrances with which the present invention can be applied are the so-called 'aromatherapy' materials. These include many components also used in fragrancery, including components of essential oils such as Clary Sage, Eucalyptus, Geranium, Lavender, Mace Extract, Neroli, Nutmeg, Spearmint, Sweet Violet Leaf and Valerian.

Typical fragrance 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, measured at one atmosphere.

It is also advantageous to encapsulate fragrance components which have a low LogP (i.e. those which will be partitioned into water), preferably with a LogP of less than 3.0.

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. The fragrance 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 fragrance suitably has a molecular weight of from 50 to 500 Dalton. Pro-fragrances can be of higher molecular weight, being typically 1 -10 kD.

Hair conditioning agent may be selected from silicone conditioning agent, cationic surfactant, cationic deposition polymer, non-silicone oily material or a combination thereof. More preferably the hair condition agent comprises silicone conditioning agent, cationic deposition polymer or mixture thereof and most preferably the hair conditioning agent is silicone conditioning agent.

Suitable silicone conditioning agents include polydiorganosiloxanes, in particular polydimethylsiloxanes which have the CTFA designation dimethicone. Also suitable are polydimethyl siloxanes having hydroxyl end groups, which have the CTFA designation dimethiconol. Also suitable are silicone gums as described for example in WO

96/31 188. These materials can impart body, volume and stylability to hair, as well as good wet and dry conditioning. Also suitable are functionalised silicones, particularly amino-functionalised silicones. Suitable non-silicone oily conditioning agents are selected from hydrocarbon oils, fatty esters and mixtures thereof.

Antidandruff agents are compounds that are active against dandruff and are typically antimicrobial agents and preferably antifungal agents. Antifungal agents typically display a minimum inhibitory concentration of about 50 mg/ml or less against

Malassezia spp. Suitable antidandruff agents include compounds selected from azole based antifungal agents, octopirox, selenium sulfide, metal pyrithione salts, and mixtures thereof. The preferred azole based antifungal agents are ketoconazole and climbazole. Preferred metal pyrithione salts are zinc, copper, silver and

zirconium pyrithione. The most preferred is zinc pyrithione.

The inner shell is preferably substantially free of protein. The inner shell may comprise inorganic material, polymer, or a mixture thereof. Inorganic material may be selected from clay, zeolite, silica, amorphous silicate, crystalline nonlayer silicate, layer silicate, calcium carbonate, sodium carbonate, sodalite, and alkali metal phosphates.

Preferably, the inner shell comprises polymer and more preferably is polymer.

Typically, the polymer may be bio-polymer and/or synthetic polymer. Suitable polymer may comprise derivative of alginate, chitosan, collegen, dextran, gelatin, cellulose, gum, starch, polyvinyl pyrrolidone, polyvinyl alcohol, cellulose ether, polystyrene, polyacrylate, polymethacrylate, polyolefin, aminoplast polymer, polyacrylamide, acrylate-acrylamide copolymer, melamine-formaldehyde condensate, urea- formaldehyde condensate, polyurethane, polysiloxane, polyurea, polyamide, polyimide, polyanhydride, polyolefin, polysulfone, polysaccaharide, polylactide, polyglycolide, polyorthoester, polyphosphazene, silicone, lipid, polyester, ethylene maleic anyhydride copolymer, styrene maleic anyhydride copolymer, ethylene vinyl acetate copolymer, lactide glycolide copolymer, or combinations of these materials. Preferably, the inner shell comprises polystyrene, polyvinyl alcohol, polyacrylate, polymethacrylates, polyolefins, aminoplast polymer, polyacrylamide, acrylate-acrylamide copolymer, melamine-formaldehyde condensate, urea-formaldehyde condensate, polyurethane, polysaccaharide or a mixture thereof. More preferably, the inner shell comprises polystyrene, modified polyvinyl alcohol, polyacrylate, polymethacrylate, polyolefin, aminoplast polymers, melamine-formaldehyde condensate, urea-formaldehyde condensate, polyurethane or a mixture thereof. Even more preferably the inner shell comprises polystyrene, modified polyvinyl alcohol, polyolefin, polyurethane or a mixture thereof. Still even more preferably, the inner shell comprises polystyrene, modified polyvinyl alcohol or a combination thereof and most preferably, the inner shell is polystyrene, modified polyvinyl alcohol, or a combination thereof.

For sake of clarity, it should be noted that the outer shell is different from the inner shell. Preferably, the outer shell comprises aromatic compound having

dihydroxylphenyl group in amount of at least 10% by weight of the outer shell, more preferably at least 30%, even more preferably at least 50% by weight of the outer shell. Most preferably, the outer shell is aromatic compound which comprises catechol group, resorcinol group or a combination thereof. In some embodiments, the outer shell is preferably substantially free from protocatechuic acid. The aromatic compound may be selected from aromatic polymer, aromatic small molecule, or a combination thereof. Preferably, the aromatic compound is aromatic small molecule. Preferably, the aromatic polymer is formed by polymerization of the aromatic small molecule.

Aromatic polymer as used herein refers to polymer having more than 2 repeating units which comprises aromatic ring, preferably benzene ring, more preferably catechol group, resorcinol group or a combination thereof. The aromatic polymer usually has a weight-average molecular weight of greater than 2,000, more preferably greater than 20,000 Daltons and even more preferably from 50,000 to 1 ,000,000 Daltons. The weight-average molecular weight may be measured by following the standard of ASTM D4001 -2013. The molecule weight of aromatic small molecule is typically no greater than 2000 Daltons, preferably from 100 to 800 Daltons, more preferably from 1 10 to 300 Daltons. lecule preferably has a molecular structure of

where R¹ is a hydroxyl group, R² is a hydrogen or hydroxyl group, R³ is a hydroxyl group when R² is a hydrogen and R³ is a hydrogen or hydroxyl group when R² is a hydroxyl group. R may be any group but preferably is group containing hydrogen, carbon, oxygen, nitrogen, sulfur, halogen or a combination thereof. More preferably R is selected from hydrogen, hydroxyl, alkyl, alkenyl, aryl, amide, ester, oxy, carbonyl, carboxyl, halogen or any combination thereof. More preferably, the aromatic small molecule comprises dopamine, 3,4-dihydroxybenzylamine, catechol, protocatechuic acid, gallic acid, 3,4-dihydroxybenzaldehyde, resorcinol, resveratrol, piceatannol, propyl gallate, their salts, or a mixture thereof. Even more preferably, the aromatic small molecule comprises catechol, piceatannol, dopamine, 3,4-dihydroxybenzylamine, 3,4-dihydroxybenzaldehyde, resveratrol, gallic acid, their salts, or a mixture thereof and most preferably the aromatic small molecule comprises catechol, piceatannol, 3,4- dihydroxybenzylamine, 3,4-dihydroxybenzylquaternium salts, 3,4- dihydroxybenzaldehyde, or a combination thereof.

The aromatic compounds are preferably aggregated together with non-covalent forces at the outside surface of the particle. The strong non-covalent forces may include charge transfer, ττ-stacking, hydrogen bonding or combination thereof. More preferably, the strong non-covalent force comprises ττ-stacking.

Without being limited to any specific theory or explanation, the present inventors believe that the dihydroxylphenyl group has strong interaction with hair and skin and therefore helps the deposition of the particles.

The outer shell may further comprise accelerant which may help and/or accelerate the formation of outer shell. The accelerant may be selected from inorganic salt, organic amine or a mixture thereof but preferably is organic amine. More preferably, the organic amine comprises alkyl amine and most preferably the organic amine is hexamethylenediamine.

The particle of the present invention may be manufactured by any process, however, it is preferred that the process for producing the benefit agent delivery particle comprises the step of:

a) encapsulating the benefit agent into capsule having the inner shell, and b) forming the outer shell on the outer surface of the inner shell. In step (a), the benefit agent may be encapsulated when the capsule having the inner shell is formed. Alternatively, the capsules having the inner shell can be formed which does not contain the benefit agent (hollow capsule) and subsequently exposed them to a benefit agent which can be adsorbed into the inner region. Preferably, the outer shell is formed by aromatic small molecule. The weight ratio of the inner shell to the aromatic small molecule is preferably in the range of 0.001 to 30, more preferably from 0.005 to 10, even more preferably from 0.01 to 5 and most preferably from 0.02 to 2. When forming the outer shell, the accelerant is preferably present. The molar ratio of the accelerant to the aromatic small molecule is preferably in the range of 1 :100 to 50:1 , more preferably from 1 :20 to 10:1 and most preferably from 1 :10 to 5:1. Preferably, the ratio of the thickness of the inner shell to the outer shell is from 1 :100 to 1000: 1 , more preferably from 1 :40 to 200: 1 to and even more preferably from 1 : 10 to 50:1 . Preferably, the outer shell has a thickness of 30 nm to 10 μηη, more preferably from 50 nm to 2μη"ΐ. The thickness of the inner shell may be measured, for example, by scanning electron microscopy. The thickness of the outer layer may be measured by halving the absolute difference of particle sizes before and after the formation of the outer shell. Preferably, the weight ratio of outer shell to inner shell is in the range of is in the range of 0.001 to 50, more preferably from 0.005 to 20, even more preferably from 0.01 to 10 and most preferably from 0.04 to 4. The present invention also provides a home care or personal case composition comprising at least one particle of the present invention. The composition may be a laundry detergent, laundry conditioner, deodorant, antiperspirant, shampoo, hair conditioner or skin care or skin cleansing product. Preferably, the composition is a personal care composition. More preferably, the composition is a skin or hair treatment composition and most preferably the composition is a hair treatment composition. The end-product composition of the invention may be in any physical form e.g., a solid bar, a paste, gel or liquid but preferably a gel or liquid. The composition is more preferably an aqueous-based liquid. Preferably, the composition is a hair treatment composition and is a liquid or gel.

The particle is typically included in the composition at levels of from 0.001 % to 10%, preferably from 0.005% to 7.55%, most preferably from 0.01 % to 5% by weight of the total composition. Depending on the end-use compositions according to the present invention will typically contain one or more of surfactants (which may be anionic, cationic, non-ionic, zwitterionic and amphoteric), silicone conditioning agents and non-silicone oily conditioning agents, suspending agents, anti-dandruff agents, thickeners, cationic deposition polymers and shading agents.

Preferred anionic surfactants are the alkyl sulfates and alkyl ether sulfates. These materials have the respective formulae R2OSO3M and R1O (C2H4O) xSC M, wherein R2 is alkyl or alkenyl of from 8 to 18 carbon atoms, x is an integer having a value of from about 1 to about 10, and M is a cation such as ammonium, alkanolamines, such as triethanolamine, monovalent metals, such as sodium and potassium, and polyvalent metal cations, such as magnesium, and calcium. Most preferably R2 has 12 to 14 carbon atoms, in a linear rather than branched chain. The total amount of anionic cleansing surfactant in hair treatment compositions of the invention generally ranges from 0.5 to 45 wt%, more preferably from 1 .5 to 20 wt%.

Preferably the surfactant comprises at least 3 wt% on total composition of an alkyl ether sulphate, in for example, a shampoo. When the composition is a conditioner a cationic surfactant is preferably included such as an alkyl ammonium material.

Hair treatment compositions according to the invention such as shampoos and conditioners suitably contain conditioning agents such as silicone conditioning agents and non-silicone oily conditioning agents.

Suitable silicone conditioning agents include polydiorganosiloxanes, in particular polydimethylsiloxanes which have the CTFA designation dimethicone. Also suitable for use in compositions of the invention (particularly shampoos and conditioners) are polydimethyl siloxanes having hydroxyl end groups, which have the CTFA designation dimethiconol. Also suitable for use in compositions of the invention are silicone gums having a slight degree of cross-linking, as are described for example in WO 96/31 188. These materials can impart body, volume and stylability to hair, as well as good wet and dry conditioning. Also suitable are functionalised silicones, particularly amino- functionalised silicones. The silicone conditioning agent is suitably present in hair treatment compositions at a level of from 0.05 to 10, preferably from 0.2 to 5, more preferably from 0.5 to 3 percent based on total weight of the composition. Suitable non-silicone oily conditioning agents are preferably selected from hydrocarbon oils, fatty esters and mixtures thereof.

It is preferred that the hair treatment composition comprises a cationic deposition polymer, which may assist in deposition of ingredients in the composition. Preferably, the cationic deposition polymer is (or comprises) cationic polygalactomannan, especially guar or cassia derived polygalactomannan modified with hydroxypropyl trimonium chloride.

It is highly preferred that compositions according to the invention should contain from 0.01 % to 2% wt. of the composition cationic deposition polymer, more preferably from 0.05 to 0.5% wt. and most preferably from 0.08 to 0.25% by weight of the composition.

Antidandruff agents are compounds that are active against dandruff and are typically antimicrobial agents and preferably antifungal agents.

Antifungal agents typically display a minimum inhibitory concentration of about 50 mg/ml or less against Malassezia spp.

Suitable antidandruff agents include compounds selected from azole based antifungal agents, octopirox, selenium sulfide, metal pyrithione salts, and mixtures thereof. The preferred azole based antifungal agents are ketoconazole and climbazole. Preferred metal pyrithione salts are zinc, copper, silver and zirconium pyrithione. The most preferred is zinc pyrithione. Preferably, the antidandruff agent is present at from 0.01 to 5% wt. of the composition, more preferably from 0.1 to 2.5% wt. of the composition. Suspending agent, if included, will preferably be present in a composition of the invention at levels of from 0.1 to 10%, more preferably from 0.5 to 6%, even more preferably from 0.9 to 4% by total weight of suspending agent based on the total weight of the composition.

The composition of the invention may contain other ingredients for enhancing performance and/or consumer acceptability. Such ingredients include dyes and pigments, pH adjusting agents, pearlescers or opacifiers, viscosity modifiers, and preservatives or antimicrobials. Each of these ingredients will be present in an amount effective to accomplish its purpose. Generally these optional ingredients are included individually at a level of up to 5% by weight of the total composition.

The composition preferably comprises at least 30% of water by weight of the composition, more preferably from 35 to 95%, even more preferably from 45 to 88%, still even more preferably from 55 to 82%, most preferably from 65 to 80% by weight of the total composition.

The particles of the invention may be incorporated into home care composition, preferably laundry composition. The active ingredient in the compositions for these laundry compositions is preferably a surface active agent or a fabric conditioning agent. More than one active ingredient may be included. For some applications a mixture of active ingredients may be used.

The compositions may be liquid, powder or tablet laundry composition. Liquids are particularly preferred. The laundry compositions are preferably main wash (fabric washing) compositions or rinse-added softening compositions. The main wash compositions may include a fabric softening agent and the rinse-added fabric softening compositions may include surface-active compounds, particularly non-ionic surface- active compounds.

It is preferred that laundry compositions according to the invention comprise one or more enzymes. When present in a composition, the enzymes may be present at levels from about 0.00001 wt.% to about 2 wt.%, from about 0.0001 wt.% to about 1 wt.% or even from about 0.001 wt.% to about 0.5 wt.% enzyme protein by weight of the composition.

The present invention also provides a method of treating a substrate, the method comprising a step of treating the substrate with a composition comprising the particle of the present invention. Preferably the substrate is selected from skin, hair, scalp and/or textile material, even more preferably the substrate is selected from skin, hair and/or scalp, and most preferably the substrate is hair and/or scalp. The particle is preferably included in a composition as described above.

The invention will now be described with reference to the following non-limiting examples.

EXAMPLES

Materials

Table 1

Material Supplier Description

Protocatechuic acid (99%) J&K Chemical

Dopamine hydrochloride Sigma-Aldrich

3,4-dihydroxybenzylamine

Sigma-Aldrich

hydrobromide (98%)

Catechol Sinopharm Chemical AR grade

Gallic acid Sigma-Aldrich

3,4-

Acros

dihydroxybenzaldehyde(97%)

Resorcinol Sinopharm Chemical

Resveratrol Sigma-Aldrich

Piceatannol J&K Chemical

Propyl gallate Sinopharm Chemical

Hexamethylenediamine Adamas Reagent

(HEM DA) (China)

Fluoresbrite yellow green (YG) microspheres (1

Polystyrene (PS) latex Polysciences

μηι, 2.5% of solid content)

Beijing Superior

Tris(hydroxymethyl)

Chemicals &

aminomethane (THAM)

Instruments Co.

Methyl cellulose TCI

Onlystar

C12-15 alkyl ester

Biotechnology Corp.

Molecular weight: 35000;

Butyral derived

hydrolysis degree: 98%; Polyvinylalcohol (mPVOH) Kuraray

modification degree of solution (15 wt%)

butyraldehyde: 10%.

Herochem Reagent

Dextran(20k)

Corp.

Dextran(200k) Sigma-Aldrich

Perfume linalool TCI Product No. L0048

Nile Red Sigma Example 1

This example demonstrates the preparation of PS latex particles coated by aromatic compound.

1 .1 Precipitates forming capability test.

The capability of forming aggregate of a series of catechol and resorcinol derivatives was tested. The catechol and resorcinol derivatives (together with accelerant if present) were dissolved in THAM-HCI buffer (10 mM, pH 8.5) in vial. The vial was kept open to air for one to five days. Then, it was checked that whether there was precipitate in the vial. If there was precipitate, that aromatic small molecule was used for the preparation of benefit delivery particles.

1 .2 Purification of latex particles

The Polystyrene (PS) latex was purified through centrifugation and washed by Dl water for three times.

1 .3 Latex particles coated by aromatic compound

The latex particles were coated by the aromatic compound. Taking dopamine hydrochloride as an example, the dopamine hydrochloride was dissolved in THAM-HCI buffer to prepare a solution with concentration of 3.0 mg/ml. 500 μΙ_ of the dopamine hydrochloride solution was added to the tube containing the centrifuge pellet (as described above). The feeding weight ratio of the dopamine hydrochloride to microspheres was 60%. The mixture was stirred for 1 day while shielded from light with aluminum foil. The mixture was then purified through centrifugation and washed by Dl water for three times. The obtained pellet was dispersed in Dl water to form dispersion with solid content of 0.5% (w/w).

The coating process using other aromatic small molecule was similar with that of dopamine hydrochloride. The feeding weight ratio of the aromatic small molecule to microspheres was 0.6. The coating time for each molecule was listed in Table 2. A sample without addition of aromatic compound was prepared by diluting the original latex with Dl water to obtain an aqueous latex solution with solid content 0.5% (w/w). Table 2

The zeta potentials of the particles were measured by zeta potential analyzer (Zetasizer Nano ZS90, Malvern, USA) at 25°C. The particles were dispersed in water with solid content of 50 ppm and the pH of the dispersion was adjusted to about 7 for measurement of zeta potential. Each test was repeated three times. The average results of zeta potentials were listed in Table 2. The change of Zeta potential of particles coated by the aromatic compound indicates that second shells were formed by the coating process.

Example 2

This example demonstrates the deposition performance on hair of PS latex particles coated by aromatic compound. 2.1 Preparation of shampoo and conditioner base

The shampoo base was formulated by following standard process for shampoo. The shampoo base contained 12 wt% of sodium laurethsulfate, 1 .60 wt% of

cocamidopropyl betaine, 1 wt% of sodium chloride, and was balanced by water. The conditioner base was also formulated by following standard process for conditioner. The conditioner base contained 3.18 wt% of behenyltrimethylammonium chloride, 4.44 wt% of cetearyl alcohol, 0.22 wt% of hydroxyethyl cellulose, 0.15 wt% of preservative, and was balanced by water. 2.2 Measurement of deposition ratio on hair

Hair switches (length of 5.5 cm, weight of 750 mg) were soaked into aqueous solution of 14 wt% of SLES at 40°C with continuous shaking for 30 minutes. Then these hair switches were rinsed by tap water thoroughly and dried at ambient environment overnight.

Three hair switches were wetted with tap water and swung to remove excess water. The three hair switches were rubbed respectively with a mixture of 70 mg of shampoo base (or condition base) and 20 μΙ of 0.5 wt% of particles water dispersion of Table 2, and rinsed by 500ml of tap water.

The switch was swung dry and then immersed in a vial containing 20 milliliters of ethyl acetate for 30 minutes. 200 microliters of the extraction liquid was withdrawn from the vial and added to a 96-well microplate for fluorescence measurement (excitation 441 nm, emission 500 nm) to afford a reading of EL The second switch was wetted with tap water and swung dry, to which 20 μΙ of the 0.5% of uncoated polystyrene latex was added. The switch was also extracted with 20 milliliters of ethyl acetate for 30 minutes. 200 microliters of the extraction liquid was withdrawn and added to the microplate and subjected to measurement using the aformentioned method and afforded a reading of Eo. The third switch was extracted without added any latex in 20 millilitres of ethyl acetate for 30 minutes. 200 microliters of the extraction liquid was taken to the microplate and afforded a reading Eb upon fluorescence measurement. The percent deposition (%deposition) was calculated according to the following equation:

E — E

%Deposition =— 100 .

V — V

£0 ^c6 Table 3 shows the deposition results on virgin and damage hair via incorporating the particles into shampoo base or conditioner base. The averages and standard derivations are calculated from 5 tests.

Table 3

Example 3

This example demonstrates the deposition performance on skin of PS latex particles coated by aromatic compound.

3.1 Measurement of deposition ratio on skin

Skin from towards the back of female pig was bought from the pork market, and was used as simulation of human skin/scalp. The pig skin was first defatted using a normal scalpel to remove subcutaneous fat and get a flat underside surface. The final thickness of the defatted pig skin was around 4 mm. The pig skin was then pre-washed by lightly finger rub using commercial washing liquid and rinsed with tap water thoroughly to remove excess oil on the surface. After that, the pig skin was cut into small pieces of 2 cmx2 cm in size and wrapped with cling film and tin foil in sequence, then frozen at -20°C for storage.

A typical skin wash procedure is shown as follows. Skin pieces were thaw out under about 25°C before use. One skin piece was placed in a Petri dish, to which 25 mg of the shampoo base (or hair conditioner base, as prepared in 2.1 of Example 2) was added together with 20 μΙ of 0.5 wt% of particles water dispersion of Table 2. The skin with the mixture onto it was then gently rubbed with another piece of pig skin for 30 seconds and the two pieces rinsed with totally 250 ml of tap water. The two pieces of skin were then immersed in a vial containing 10 milliliters of ethyl acetate for 20 minutes. 200 microliters of the extraction liquid was withdrawn from the vial and added to a 96-well microplate for fluorescence measurement (excitation 441 nm, emission

500 nm) to afford a reading of EL In addition, one skin piece was placed in a Petri dish, to which 20 μΙ of the 0.5% of uncoated polystyrene was added. The skin with the latex was then immersed in a vial containing 10 milliliters of ethyl acetate for 20 minutes. 200 microliters of the extraction liquid was withdrawn from the vial and added to a 96-well microplate for fluorescence measurement (excitation 441 nm, emission 500 nm) to afford a reading of Eo.

The percent deposition (% deposition) was calculated according to the following equation:

%Deposition =— ^Lx l00

Table 4

^*: not tested

As can be seen from Table 3 and Table 4, the benefit delivery particles of the present invention had better deposition performance on at least one substrate selected from virgin hair, damage hair in at least one composition with at least one base.

Example 4

This example demonstrates the deposition performance on skin of crosslinked modified polyvinyl alcohol (mPVOH) particles coated by aromatic compound.

4.1 Preparation of dextran(20k)-aldehyde and dextran(200k)-aldehyde

50 ml sodium periodate (Nal0₄) solution (4 wt%) was prepared in a single-neck flask. The pH value of the solution was adjusted to about 3.5 by adding 0.5 ml 1.0M HCI and the solution was then protected in dark by covering the flask with aluminum foil. 1 .5 g dextran(20k) was added into the above solution and allowed to dissolve completely. Then the resultant mixture was heated to 40°C under magnetic stirring and kept for further 3 h. After that, the reaction mixture was dialyzed utilizing a dialysis tube with cut-off Mw 7000 for 48 h and the resultant solution of dextran(20k)-CHO was then ready for use as crosslinker. The synthetic route for dextran(200k)-aldehyde was similar as that described above except that dextran(200k) was used as raw material instead of dextran(20k).

The concentration of aldehyde group (-CHO concentration) of dextran-CHO product was measured to be 0.2 mol/L.

4.2 Preparation of crosslinked mPVOH capsule

20 mg affinity polymer (methyl cellulose), 200 mg dormant agent (C12-15 alkyl ester) and 480 μΙ of perfume (Linalool with 2 wt%₀ Nile Red) were mixed together and the mixture stirred until the polymer dissolved/dispersed completely. The mixture was then added into 32.0 g of 0.5 wt% mPVOH solution in a double-neck flask and emulsified by homogenizer at 6,000 rpm for 2 minutes. 0.4 ml dextran(20k)-CHO and 0.4ml dextran(200k)-CHO solution as prepared in 4.1 were added into the emulsion as crosslinker. The resultant mixture was emulsified at rate 6,000 rpm for further 3 minutes. Then the flask was transferred into a water bath and heated from room temperature to 50°C at rate of about 1°C/min under mild magnetic stir. After being kept at 50°C for 1 .5 hour, 500 μΙ of 1 M HCI was added to adjust pH of the mixture to 2-3 and the resultant mixture stirred for another 4.5 h at 50°C. The flask was then taken out from the water bath and the perfume capsules could be found enriched in upside of the mixture.

4.3 mPVOH capsule coating by aromatic compound

Particles in Table 5 were prepared. The coating process was similar with that in 1 .3 of Example 1. Table 5

4.4 Characterization of particle

The sizes of the particles were measured based upon 10 capsules from the

microscopic image (Microscope Leica DC 300F, Germany). The zeta potentials of the particles were measured by zeta potential analyzer (Zetasizer Nano ZS90, Malvern, USA). The particles were dispersed in water with solid content of 50 ppm and the pH of the dispersion was adjusted to about 7 for measurement of zeta potential. The results of zeta potentials and particle sizes were listed in Table 6.

Table 6

4.5 Deposition performance on skin

The deposition performance of the particles in Table 6 was tested by following similar procedure as described in 3.1 of Example 3 except that acetone was used as extraction solvent instead of ethyl acetate; the pig skin was immersed into 10ml of acetone for 30 minutes followed by ultrasonication for 2 minutes; and the excitation and emission wavelength are 470 and 618 nm, respectively. As can be seen from Table 6, the particles of the present invention have better deposition on pig skin than the capsules without coating of aromatic compound.

Claims

A benefit agent delivery particle comprising:

a) a core comprising benefit agent;

b) an inner shell; and

c) an outer shell comprising at the outside surface of the particle aromatic compound having dihydroxylphenyl group.

The particle according to claim 1 wherein the zeta potential of the particle is at least -39 mV, preferably from -30 mV to 80 mV.

The particle according to claim 1 or 2 wherein the particle size is 50 nm to 800 μηη, preferably from 300 nm to 200 μηη.

The particle according to any one of the preceding claims wherein the benefit agent comprises fragrance, preferably the benefit agent is fragrance.

The particle according to any one of the preceding claims wherein the outer shell is aromatic compound comprising catechol group, resorcinol group or a combination thereof.

The particle according to any one of the preceding claims wherein the aromatic compound is selected from aromatic polymer, aromatic small molecule, or a combination thereof and the aromatic polymer is formed by polymerization of the aromatic small molecule.

The particle according to claim 6 wherein the aromatic small molecule comprises catechol, piceatannol, dopamine, 3,4-dihydroxybenzylamine, 3,4- dihydroxybenzaldehyde, resveratrol, gallic acid, salts thereof, or a mixture thereof, preferably the aromatic small molecule comprises catechol, piceatannol, 3,4- dihydroxybenzylamine, 3,4-dihydroxybenzylquaternium salt, 3,4- dihydroxybenzaldehyde, or a combination thereof.

8. The particle according to any one of the preceding claims wherein the inner shell is polymer; preferably comprises polystyrene, modified vinyl alcohol polymer, or a combination thereof.

9. The particle according to any one of the preceding claims wherein the weight ratio of the outer shell to the inner shell is from 1 :200 to 10:1.

10. A process for the production of benefit agent delivery particles according to any one of claims 1 to 9 comprising the step of:

a) encapsulating the benefit agent into inner shell, and

b) forming the outer shell on the outer surface of the inner shell.

1 1 . A home care or personal case composition comprising at least one particle of any one of claims 1 to 9, the composition preferably being a laundry detergent, laundry conditioner, deodorant, antiperspirant, shampoo, hair conditioner, skin care or skin cleansing product.

12. The composition according to claim 1 1 wherein the composition is a hair treatment composition and is a liquid or gel.

13. A method of treating a substrate comprising a step of treating the substrate with a composition comprising particles of any one of claims 1 to 9.

14. The method according to claim 13 wherein the substrate is selected from skin, hair, scalp, and/or textile material, preferably the substrate is hair and/or scalp.

15. Use of the particle of any one of claims 1 to 9 for improved deposition, preferably onto skin, hair, scalp, and/or textile materials, more preferably onto hair and/or scalp.