Microcapsules and hair care compositions

Abstract

The core-shell microcapsules have a liquid core and an outer shell, the liquid core comprising a solvent and a piroctone compound, and the shell comprising a polyurea containing an aminosulfonic acid.

Description

[Technical field]

[0001] The present invention relates to microcapsules containing a piroctone compound, methods of making microcapsules containing a piroctone compound, and anti-dandruff hair care compositions, particularly compositions containing a surfactant and a piroctone compound as an anti-dandruff active. [Background technology]

[0002] Dandruff is a problem that affects many parts of the world. The condition is manifested by the shedding of clumps of dead skin cells from the scalp. These are white in color and provide an aesthetically pleasing appearance. The contributing factors to dandruff are certain members of the Malassezia yeast family. To combat these, hair treatment compositions have been developed that contain various actives for anti-dandruff benefits. Piroctone compounds, such as piroctone olamine, are one such active.

[0003] In some cases, the anti-dandruff agents can be encapsulated to aid deposition and increase the effectiveness of the anti-dandruff active.

[0004] Encapsulation of anti-dandruff agents is disclosed in EP1702674 (Cognis).

[0005] WO2017 / 084826 (Unilever) discloses core-shell microcapsules in which the liquid core of the microcapsule comprises a solvent and the anti-dandruff agent climbazole is dissolved in the solvent.

[0006] However, there remains a need for a stable system that encapsulates the piroctone compound and slowly releases the piroctone upon drying. Slow release of the active upon drying is believed to provide longer lasting anti-dandruff benefits. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] EP1702674 [Patent Document 2] WO2017 / 084826 Summary of the Invention [Means for solving the problem]

[0008] According to the present invention, there is provided a core-shell microcapsule having a liquid core and an outer shell, the liquid core comprising a solvent and a piroctone compound, and the shell comprising a polyurea comprising an aminosulfonic acid.

[0009] Without wishing to be bound by theory, it is believed that the addition of aminosulfonic acid to the shell polymer has the effect of reducing the degree to which the microcapsules collapse upon drying on the scalp, thus increasing the longevity of efficacy of the sebum-soluble anti-dandruff actives.

[0010] The present invention also relates to a hair care composition comprising a surfactant and at least 0.05% by weight of the total composition of the above core shell microcapsules. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Detailed Description of the Invention The compositions of the present invention include core-shell microparticles in which the shell polyurea is formed from an aminosulfonic acid.

[0012] Preferably, the polyurea shell comprises isocyanate and amine monomer units in addition to aminosulfonic acid. It is preferred that the isocyanate is aliphatic, more preferably aliphatic and cyclic or branched.

[0013] The amine units used to form the polyurea may be monomeric in nature or may be polymeric amines.

[0014] Preferably, the aliphatic isocyanate monomers used to prepare the polyurea include isopherone diisocyanate and / or hexamethylene diisocyanate.

[0015] The polyurea shell comprises an aminosulfonic acid, preferably the amino acid sulfonic acid is taurine.

[0016] Preferably, the aminosulfonic acid is added during preparation of the polyurea shell at a level of at least 0.1% by weight relative to the isocyanate, more preferably at least 1% by weight relative to the isocyanate, and most preferably at least 5% by weight relative to the isocyanate.

[0017] Preferably, the amines used to prepare the polyurea further include diethylenetriamine, tris(2-aminoethyl)amine, bis(hexamethylene)triamine and / or polyethyleneimine.

[0018] The polymerization process may use a Pickering emulsion type process. Such a method is taught in WO 2008 / 145547. Shell chemistries known to those skilled in the art based on the Pickering emulsion method are melamine formaldehyde, urea formaldehyde and melamine glioxal. Alternatively, the polymerization process may be carried out by interfacial polymerization. A suitable method for producing polyurea microcapsules is taught in US 2013 / 330292. Shell chemistries based on interfacial polymerization to form the polyurea of ​​the present invention are known to those skilled in the art and are polyureas formed by the reaction of polyisocyanates with polyamines.

[0019] The diameter of the core-shell microcapsules is preferably at least 5 microns. The diameter should be less than 50 microns, so that the particles are larger than they would be visible to the naked eye. Preferably, the diameter of the microcapsules is in the range of 5 to 20 microns, more preferably 10 to 15 microns.

[0020] A deposition aid having affinity for hair roots or scalp can be grafted onto the outside of the microcapsule shell. Preferred deposition aids and grafting methods for preferred shell materials are taught elsewhere and are known to those skilled in the art. Most preferred are grafted dextran; HPC (and other hydrophobically modified polysaccharides); more preferred are chitosan salts. WO 14 / 064121 discloses the use of chitosan salts as deposition aids to increase deposition of microcapsules on hair, WO 13 / 026656 discloses the use of dextran as deposition aids for use in depositing microcapsules from hair shampoo, and WO 13 / 026657 discloses the use of HPMC and HEMC as deposition aids to aid deposition of microcapsules from hair shampoo.

[0021] Advantageously, the deposition aid is added either before or during step (d) in order to be covalently attached to the surface of the microcapsules. Alternatively, a spacer may be attached to the surface of the microcapsules and then the deposition aid is reacted on the spacer. Polyethylene glycol is a suitable spacer. Preferred deposition aids are selected from the group consisting of grafted dextran, HPC (and other hydrophobically modified polysaccharides) and peptides. Cationic polymers, especially chitosan, are preferred.

[0022] The present invention also provides a hair shampoo comprising a surfactant and at least 0.05% by weight, preferably 0.1 to 1.0% by weight, of core-shell microcapsules based on the total composition.

[0023] The ratio of solvent to piroctone compound in the shell microcapsules is less than 15:1, preferably less than 11:1.

[0024] Piroctone compounds for use in the present invention include piroctonic acid, primary, secondary and tertiary olamine salts of piroctonic acid (e.g., diethanolamine and triethanolamine salts), and mixtures thereof, preferably piroctonic acid, primary olamine salts of piroctonic acid (i.e., piroctone olamine, also known as Octpirox®), and mixtures thereof, more preferably piroctonic acid.

[0025] solvent It is essential that the solvent in the core-shell microparticles can efficiently dissolve the piroctone compound or the number of microcapsules required in the hair care composition would be unbearably large. The preferred solvent is aromatic. The preferred minimum dissolving power of the present invention is such that when the piroctone compound is dissolved, a maximum of 8 times, preferably a maximum of 5 times, of the solvent is used. Once dissolved, it is important that the piroctone compound remains in solution because the microcapsules will break down and deliver their liquid core payload, which aids in the transport of the piroctone compound. The preferred solvent includes fragrance ingredients, where they contain at least 50% by weight of mid notes and low notes to provide low volatility so that the dissolved piroctone compound will remain in solution after the microcapsules break down. Thus, the solvent system should avoid volatile solvents whose use causes the piroctone compound to crystallize from the open test solution in less than 1 hour at 25°C. The cLog P of the solvent should preferably be greater than 1.8, more preferably greater than 2, and most preferably greater than 3. A suitable solvent, which can be used in admixture or alone, is heptanone.

[0026] Piroctone compound levels The level of piroctone compound in the microcapsules must be as high as possible without going out of solution. For the preferred solvent system, the level per particle is typically at least twice that of prior art latex particles. This means that the volume of the delivery system is reduced compared to the prior art.

[0027] Preferably, the piroctone compound is present at 0.01 to 1% by weight of the composition, more preferably 0.05 to 0.6% by weight, most preferably 0.01 to 0.5% by weight.

[0028] Surfactant Systems The composition may be in any common product form used as a hair care product for treating hair. Preferably, it is a rinse-off composition, and most preferably, it is an anti-dandruff shampoo composition.

[0029] The composition may include any ingredient commonly found in hair care products, depending on the product form.

[0030] For example, if the composition is a shampoo, it will contain a surfactant system that includes at least one cleansing surfactant suitable for use in shampoos.If the composition is intended to provide conditioning benefits, it will contain a conditioning active.Suitable conditioning actives include fatty alcohols, silicones and cationic surfactants.

[0031] Examples of suitable anionic detergent surfactants are alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alkanoyl isethionates, alkyl succinates, alkyl sulfosuccinates, alkyl ether sulfosuccinates, N-alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, and alkyl ether carboxylic acids, and their salts, in particular their sodium, magnesium, ammonium, and mono-, di-, and triethanolamine salts. The alkyl and acyl groups generally contain 8 to 18, preferably 10 to 16, carbon atoms and may be unsaturated. The alkyl ether sulfates, alkyl ether sulfosuccinates, alkyl ether phosphates, and alkyl ether carboxylic acids, and their salts, may contain 1 to 20 ethylene oxide or propylene oxide units per molecule.

[0032] Typical anionic cleansing surfactants for use in the compositions of the present invention include sodium oleyl succinate, ammonium lauryl sulfosuccinate, sodium lauryl sulfate, sodium lauryl ether sulfonate, sodium lauryl ether sulfosuccinate, ammonium lauryl sulfate, ammonium lauryl ether sulfonate, sodium dodecylbenzene sulfonate, triethanolamine dodecylbenzene sulfonate, sodium cocoyl isethionate, sodium lauryl isethionate, lauryl ether carboxylic acid and sodium N-lauryl sarcosinate.

[0033] Preferred anionic surfactants are the alkyl sulfates and alkyl ether sulfates. These materials have the formula ROSO3M and RO(C2H4O)xSO3M, respectively, where R is an alkyl or alkenyl of 8 to 18 carbon atoms, x is an integer having a value of about 1 to about 10, and M is an alkanolamine such as ammonium, triethanolamine, monovalent metals such as sodium and potassium, and polyvalent metal cations such as magnesium and calcium. Most preferably, R has 12 to 14 carbon atoms in a straight, rather than branched, chain.

[0034] Preferred anionic cleansing surfactants are selected from sodium lauryl sulfate and sodium lauryl ether sulfate (n) EO, where n is from 1 to 3; more preferably sodium lauryl ether sulfate (n) EO, where n is from 1 to 3; most preferably sodium lauryl ether sulfate 1EO.

[0035] Preferably the level of alkyl ether sulfate is from 0.5% to 25%, more preferably from 3% to 18%, most preferably from 6% to 15% by weight of the total composition.

[0036] The total amount of anionic cleansing surfactant in the composition of the present invention is generally in the range of 0.5% to 45% by weight, more preferably 1.5% to 20% by weight.

[0037] The composition of the present invention may contain a non-ionic surfactant, most preferably present in the range of 0 to 5% by weight.

[0038] Nonionic surfactants that can be included in the compositions of the present invention include aliphatic (C8-C 18 ) Condensation products of primary or secondary straight or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide, generally having from 6 to 30 ethylene oxide groups. Alkyl ethoxylates are particularly preferred. Most preferred are alkyl ethoxylates having the formula R-(OCH2CH2)nOH, where R is C 12-15 where n is 5 to 9.

[0039] Other suitable nonionic surfactants include mono- or dialkyl alkanolamides. Examples include coco mono- or di-ethanolamide and coco mono-isopropanolamide.

[0040] Further nonionic surfactants that may be included in the shampoo compositions of the present invention are the alkyl polyglycosides (APGs). Typically, APGs are those that contain an alkyl group linked (optionally via a bridging group) to a block of one or more glycosyl groups. Preferred APGs are defined by the formula: [ka] where R is a branched or straight chain alkyl group which may be saturated or unsaturated, and G is a sugar group. R is from about C5 to about C 20 Most preferably, R can represent an alkyl chain having an average length of up to about C 9.5 From about C 10.5G represents an alkyl chain having an average length of up to 10 ...

[0041] The degree of polymerization n can have a value of about 1 to about 10 or more. Preferably, the value of n is about 1.1 to about 2. Most preferably, the value of n is about 1.3 to about 1.5.

[0042] Alkyl polyglycosides suitable for use in the present invention are commercially available and include, for example, the materials identified as: Oramix NS10 ex Seppic, Plantaren 1200 and Plantaren 2000 ex BASF (DeWolf).

[0043] Other sugar-derived nonionic surfactants that can be included in the composition of the present invention include, for example, C 12 -C 18 C such as N-methylglucamide 10 -C 18 N-alkyl (C1-C6) polyhydroxy fatty acid amides, and C 10 -C 18 Included are N-alkoxy polyhydroxy fatty acid amides such as N-(3-methoxypropyl) glucamide.

[0044] The amphoteric or zwitterionic surfactant may be present in an amount ranging from 0.5% to about 8%, preferably from 1% to 4% by weight of the total shampoo composition.

[0045] Examples of amphoteric or zwitterionic surfactants include alkylamine oxides, alkylbetaines, alkylamidopropylbetaines, alkylsulfobetaines (sultaines), alkylglycinates, alkylcarboxyglycinates, alkylamphoacetates, alkylamphopropionates, alkylamphoglycinates, alkylamidopropylhydroxysultans, acyltaurates and acylglutamates, where the alkyl and acyl groups have from 8 to 19 carbon atoms.Typical amphoteric and zwitterionic surfactants for use in shampoos of the present invention include laurylamine oxide, cocodimethylsulfopropylbetaine, laurylbetaine, cocamidopropylbetaine and sodium cocoamphoacetate.

[0046] Particularly preferred amphoteric or zwitterionic surfactant is cocamidopropyl betaine.Mixtures of any of the above-mentioned amphoteric or zwitterionic surfactants may also be suitable.Preferred mixtures are mixtures of cocamidopropyl betaine and additional amphoteric or zwitterionic surfactants as described above.Preferred additional amphoteric or zwitterionic surfactant is sodium cocoamphoacetate.

[0047] Particularly preferred compositions include a surfactant system comprising 10-20% by weight of the composition sodium lauryl sulfate or sodium lauryl ether sulfate (n)EO, where n is in the range of 1 to 3; 0.5-5% by weight of the composition cocamidopropyl betaine; and 0.5-5% by weight of the composition sodium cocoamphoacetate or sodium lauryl cocoamphoacetate.

[0048] Other Ingredients The composition may also include one or more of the following non-essential ingredients:

[0049] pH adjuster The pH of the composition is preferably in the range of 5 to 8, more preferably in the range of 6 to 7, for example 6.5. The pH of the composition can be adjusted using an alkaline agent (such as, for example, sodium hydroxide) or an acidic agent (such as citric acid) as is well known in the art.

[0050] Cationic Polymer Cationic polymers are preferred ingredients in hair care compositions according to the present invention to enhance the conditioning performance of the composition.

[0051] The cationic polymer may be a homopolymer or may be formed from two or more types of monomers. The molecular weight of the polymer generally ranges from 5,000 to 10,000,000, typically at least 10,000, preferably from 100,000 to about 2,000,000. The polymer has cationic nitrogen-containing groups, such as quaternary ammonium or protonated amino groups, or mixtures thereof.

[0052] The cationic nitrogen-containing group is generally present as a substituent on the functional group of all monomer units of the cationic polymer. Thus, if 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 cationic to non-cationic monomer units is selected to give a polymer with a cationic charge density in the required range.

[0053] Suitable cationic conditioning polymers include, for example, copolymers of vinyl monomers having cationic amine or quaternary ammonium functionality with water-soluble spacer monomers such as (meth)acrylamides, alkyl and dialkyl (meth)acrylamides, alkyl (meth)acrylates, vinyl caprolactone, and vinyl pyrrolidine. The alkyl and dialkyl substituted monomers preferably have C1-C7 alkyl groups, more preferably C 1~3 Other suitable spacer monomers include vinyl esters, vinyl alcohol, maleic anhydride, propylene glycol, and ethylene glycol.

[0054] The cationic amines may be primary, secondary or tertiary amines, depending on the particular species and the pH of the composition. Generally, secondary and tertiary amines, especially tertiary amines, are preferred.

[0055] Amine-substituted vinyl monomers and amines can be polymerized in the amine form and then converted to ammonium by quaternization.

[0056] The cationic conditioning polymer may comprise a mixture of monomer units derived from amine and / or quaternary ammonium substituted monomers and / or compatible spacer monomers.

[0057] Suitable cationic conditioning polymers include, for example, the following: a) Copolymers of 1-vinyl-2-pyrrolidine and 1-vinyl-3-methyl-imidazolium salts (e.g., chloride salts) are 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 trade name (e.g., LUVIQUAT FC 370); b) Copolymer of 1-vinyl-2-pyrrolidine and dimethylaminoethyl methacrylate, known in the industry (CTFA) as Polyquaternium-11. This material is commercially available from Gaf Corporation (Wayne, NJ, USA) under the GAFQUAT trade name (e.g., GAFQUAT 755N); c) cationic diallyl quaternary ammonium-containing polymers, including, for example, dimethyldiallylammonium chloride homopolymer and copolymers of acrylamide and dimethyldiallylammonium chloride (referred to in the industry (CTFA) as Polyquaternium 6 and Polyquaternium 7, respectively); d) mineral acid salts of aminoalkyl esters of homo- and copolymers of unsaturated carboxylic acids having 3 to 5 carbon atoms (described in U.S. Pat. No. 4,009,256); e) Cationic polyacrylamides (described in WO 95 / 22311).

[0058] Other cationic conditioning polymers that may be used include cationic polysaccharide polymers such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives.Suitably, such cationic polysaccharide polymers have a charge density in the range of 0.1 to 4 meq / g.

[0059] Cationic polysaccharide polymers suitable for use in the compositions of the present invention include those of the formula: [ka] where A is an anhydroglucose residue, such as a starch or cellulose anhydroglucose residue. R is an alkylene, oxyalkylene, polyoxyalkylene, or hydroxyalkylene group, or a combination thereof. 1 , R 2 and R 3 independently represent an alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, or alkoxyaryl group, each of which contains up to about 18 carbon atoms. The total number of carbon atoms in each cationic moiety (i.e., R 1 , R 2 and R 3 The total number of carbon atoms in is preferably about 20 or less, and X is an anionic counterion.

[0060] Cationic celluloses are available from Amerchol Corp (Edison, NJ, USA) as their Polymer JR™ and LR™ series of polymers, as salts of hydroxyethylcellulose reacted with trimethylammonium-substituted epoxides, referred to in the industry (CTFA) as Polyquaternium 10. Another type of cationic cellulose includes the polymeric quaternary ammonium salts of hydroxyethylcellulose reacted with lauryldimethylammonium-substituted epoxides, referred to in the industry (CTFA) as Polyquaternium 24. These materials are available from Amerchol Corp (Edison, NJ, USA) under the trade name Polymer LM-200.

[0061] Other suitable cationic polysaccharide polymers include quaternary nitrogen-containing cellulose ethers (described, for example, in U.S. Pat. No. 3,962,418) and copolymers of etherified cellulose and starch (described, for example, in U.S. Pat. No. 3,958,581).

[0062] 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).

[0063] Examples are JAGUAR C13S, which has a low degree of substitution of cationic groups and a high viscosity, JAGUAR C15, which has a medium degree of substitution and low viscosity, JAGUAR C17 (high degree of substitution, high viscosity), JAGUAR C16, a hydroxypropylated cationic guar derivative containing low levels of substitution and cationic quaternary ammonium groups, and JAGUAR 162, a medium viscosity guar with high clarity and low degree of substitution.

[0064] Preferably, the cationic conditioning 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. It is believed that the presence of the cationic polymer promotes the deposition of the encapsulate containing the grafted HPC deposition aid.

[0065] The cationic conditioning polymer will generally be present in compositions of the invention at a level of from 0.01 to 5%, preferably from 0.05 to 1%, more preferably from 0.08 to 0.5% by weight of the composition.

[0066] When a cationic conditioning polymer is present in the hair care composition, the copolymer has a mean diameter (D measured by light scattering using a Malvern particle sizer) of 2 micrometers or less. 3,2 It is preferred that the emulsion particles have a molecular weight of 1.0 or more.

[0067] The hair care compositions of the present invention are preferably aqueous, i.e. they have water or an aqueous solution or a lyotropic liquid crystal phase as their major component.Suitably, the compositions will comprise 50 to 98% by weight of water, preferably 60 to 90% by weight, based on the total weight of the composition.

[0068] silicone The anti-dandruff hair composition may further comprise 0.1 to 10% by weight, preferably 0.1 to about 8% by weight, more preferably about 0.3 to about 5% by weight of silicone.

[0069] Preferred suitable silicones may include polyalkyl siloxanes, polyaryl siloxanes, polyalkylaryl siloxanes, polyether siloxane copolymers, amino silicones and mixtures thereof.

[0070] The silicone may be present as a free silicone oil or in the form of a silicone emulsion.

[0071] Preferably, the silicone is present in the form of a silicone emulsion, more preferably an aqueous surfactant stabilized emulsion of silicone particles having a number average particle size in the range of 10 to 1,000 nm, most preferably about 100 to about 500 nm.

[0072] Aminosilicones are often formulated into hair compositions. Aminosilicones are silicones that contain at least one primary amine, secondary amine, tertiary amine or quaternary ammonium group. High molecular weight silicone gums can also be utilized. Another useful type is crosslinked silicone elastomers, such as dimethicone / vinyl / dimethicone crosspolymers (e.g., Dow Corning 9040 and 9041).

[0073] Examples of suitable preformed silicone emulsions include emulsions DC2-1766, DC2-1784, DC-1785, DC-1786, DC-1788, and microemulsions DC2-1865 and DC2-1870, all of which are available from Dow Corning.All of these are dimethiconol emulsions or microemulsions.Also suitable are amodimethicone emulsions, such as DC939 (from Dow Corning) and SME253 (from GE Silicones).

[0074] Suspending Agent Preferably, the hair care composition of the present invention further comprises a suspending agent. Suitable suspending agents are selected from polyacrylic acid, crosslinked polymers of acrylic acid, copolymers of acrylic acid and hydrophobic monomers, copolymers of carboxylic acid-containing monomers and acrylic esters, crosslinked copolymers of acrylic acid and acrylic esters, heteropolysaccharide gums and crystalline long-chain acyl derivatives. The long-chain acyl derivatives are desirably selected from ethylene glycol stearates, alkanolamides of fatty acids having 16 to 22 carbon atoms, and mixtures thereof. Ethylene glycol distearate and polyethylene glycol 3 distearate are preferred long-chain acyl derivatives, as they impart pearlescence to the composition. Polyacrylic acids are commercially available as Carbopol 420, Carbopol 488 or Carbopol 493. Polymers of acrylic acid crosslinked with polyfunctional agents can also be used; they are commercially available as Carbopol 910, Carbopol 934, Carbopol 941 and Carbopol 980. An example of a suitable copolymer of carboxylic acid containing monomers and acrylic esters is Carbopol 1342. All Carbopol™ materials are available from Goodrich.

[0075] A suitable crosslinked polymer of acrylic acid and acrylate esters is Pemulen TR 1 or Pemulen TR 2. A suitable heteropolysaccharide gum is xanthan gum, for example available as Kelzan mu.

[0076] Mixtures of any of the above suspending agents may be used, with mixtures of acrylic acid crosslinked polymers and crystalline long chain acyl derivatives being preferred.

[0077] Suspending agents, if included, will generally be present in hair care compositions of the present invention at a level of from 0.1 to 10% by weight, preferably from 0.5 to 6% by weight, more preferably from 0.9 to 4% by weight based on the total weight of the composition.

[0078] Non-silicone oil conditioning ingredients Compositions according to the present invention may also include dispersed, non-volatile, water-insoluble oily conditioning agents.

[0079] This component is dispersed in the composition in the form of droplets which form a separate discontinuous phase from the aqueous continuous phase of the composition, in other words, the oily conditioning agent will be present in the shampoo composition in the form of an oil-in-water emulsion.

[0080] By "insoluble" it is meant that the material does not dissolve in water (distilled or equivalent) at a concentration of 0.1 percent (w / w) at 25°C. Suitably, the D3 2 average droplet size of the oil-based conditioning component is at least 0.4, preferably at least 0.8, more preferably at least 1 μm. Further, the D3 2 average droplet size of the oil-based conditioning component is preferably 10 or less, more preferably 8 or less, more preferably 5 or less, even more preferably 4 or less, and most preferably 3.5 μm or less.

[0081] The oily conditioning agent may be suitably selected from oily or fatty materials, and mixtures thereof.

[0082] Oily or fatty materials are preferred conditioning agents in shampoo compositions of the present invention to add shine to the hair and enhance dry combing and dry hair feel.

[0083] Preferred oily and fatty materials generally have a viscosity of less than 5 Pa.s, more preferably less than 1 Pa.s, most preferably less than 0.5 Pa.s, for example less than 0.1 Pa.s, measured at 25° C. using a Brookfield viscometer (e.g. Brookfield RV) using spindle 3 operating at 100 rpm.

[0084] Oily and fatty materials having higher viscosities may be used. For example, materials having viscosities on the order of 65 Pa·s may be used. The viscosity of such materials (i.e., materials having viscosities of 5 Pa·s or greater) may be measured by means of a glass capillary viscometer as further described in Dow Corning Corporate Test Method CTM 004, dated July 20, 1970.

[0085] Suitable oily or fatty substances are selected from hydrocarbon oils, fatty esters and mixtures thereof.

[0086] Hydrocarbon oils include cyclic hydrocarbons, straight chain aliphatic hydrocarbons (saturated or unsaturated), and branched chain aliphatic hydrocarbons (saturated or unsaturated). Straight chain hydrocarbon oils preferably contain from about 12 to about 30 carbon atoms. Branched chain hydrocarbon oils can, and typically do, contain more carbon atoms. Polymeric hydrocarbons of alkenyl monomers, such as C2-C6 alkenyl monomers, are also suitable. These polymers can be straight chain or branched chain polymers. Straight chain polymers are typically relatively short in length and generally have a total number of carbon atoms as described above for straight chain hydrocarbons. Branched chain polymers can have substantially higher chain lengths. The average molecular weight of such materials can vary widely, but is typically up to about 2000, more desirably in the range of about 200 to about 1000, and more desirably in the range of about 300 to about 600.

[0087] Specific examples of suitable hydrocarbon oils include paraffin oil, mineral oil, saturated and unsaturated dodecane, saturated and unsaturated tridecane, saturated and unsaturated tetradecane, saturated and unsaturated pentadecane, saturated and unsaturated hexadecane, and mixtures thereof. Branched chain isomers of these compounds, as well as higher chain length hydrocarbons, can also be used. Exemplary branched chain isomers are highly branched saturated or unsaturated alkanes, such as permethyl-substituted isomers of hexadecane and eicosane, such as 2,2,4,4,6,6,8,8-dimethyl-10-methylundecane and 2,2,4,4,6,6-dimethyl-8-methylnonane, sold by Permethyl Corporation. A further example of a hydrocarbon polymer is polybutene, such as a copolymer of isobutylene and butene. A commercially available material of this type is L-14 polybutene from Amoco Chemical Co (Chicago, IL, USA).

[0088] Particularly preferred hydrocarbon oils are the various grades of mineral oil. Mineral oils are clear oily liquids obtained from petroleum from which the waxes have been removed and the more volatile fractions removed by distillation. The fractions which distill between 250°C and 300°C are called mineral oils and consist of a mixture of hydrocarbons in the range C16H34 to C21H4. Suitable commercially available materials of this type include Sirius M85 and Sirius M125 available from Silkolene.

[0089] Suitable fatty esters are characterized by having at least 10 carbon atoms, and include esters with hydrocarbyl chains derived from fatty acids or alcohols, such as monocarboxylic acid esters, polyhydric alcohol esters, and dicarboxylic acid esters and tricarboxylic acid esters. The hydrocarbyl groups of the fatty esters of the present invention may also contain other compatible functional groups, such as amide and alkoxy moieties (e.g., ethoxy or ether bonds), or may have covalent bonds. Monocarboxylic acid esters include esters of alcohols and / or acids of the formula R-COOR, where R- and R independently represent alkyl or alkenyl groups, and the total number of carbon atoms in R- and R is at least 10, preferably at least 20.

[0090] Specific examples include, for example, alkyl and alkenyl esters of fatty acids having aliphatic chains containing from about 10 to about 22 carbon atoms, alkyl and / or alkenyl fatty alcohol carboxylates having alkyl and / or alkenyl alcohol-derived aliphatic chains containing from about 10 to about 22 carbon atoms, and benzoate esters of fatty alcohols containing from about 12 to 20 carbon atoms.

[0091] The monocarboxylic acid ester does not necessarily have to include at least one chain having at least 10 carbon atoms, so long as the total number of aliphatic chain carbon atoms is at least 10. Examples include isopropyl isostearate, hexyl laurate, isohexyl laurate, isohexyl palmitate, isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate, decyl stearate, isopropyl isostearate, dihexyldecyl adipate, lauryl lactate, myristyl lactate, cetyl lactate, oleyl stearate, oleyl oleate, oleyl myristate, lauryl acetate, cetyl propionate, and oleyl adipate. Di- and trialkyl and alkenyl esters of carboxylic acids can also be used. These include, for example, C7-C12 alkyl esters of succinic acid, glutaric acid, adipic acid, hexanoic acid, heptanoic acid, and octanoic acid. 22Specific examples include esters of C4 to C8 dicarboxylic acids such as esters (preferably C1 to C9). Examples include diisopropyl adipate, diisohexyl adipate, and diisopropyl sebacate. Other specific examples include isocetyl stearoyl stearate, and tristearyl citrate.

[0092] Polyhydric alcohol esters include alkylene glycol esters such as ethylene glycol mono- and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol monooleate, polypropylene glycol monostearate, ethoxylated propylene glycol monostearate, polyglycerol polyfatty acid esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and mono-, di-, and triglycerides.

[0093] Particularly preferred fatty esters are mono-, di- and triglycerides, more specifically long chain carboxylic acid mono-, di- and triesters such as C7-C22 carboxylic acids of glycerol. A variety of these types of materials can be derived from vegetable and animal fats and oils such as coconut oil, castor oil, safflower oil, sunflower oil, cottonseed oil, corn oil, olive oil, cod liver oil, almond oil, avocado oil, palm oil, sesame oil, peanut oil, lanolin and soybean oil. Synthetic oils include triolein and tristearate glyceryl dilaurate.

[0094] Particular examples of preferred materials include cocoa butter, palm stearin, sunflower oil, soybean oil and coconut oil. The oily or fatty substances are suitably present at a level of from 0.05 to 10%, preferably from 0.2 to 5%, more preferably from about 0.5 to 3% by weight.

[0095] The compositions of the present invention preferably contain no more than 3% by weight of a styling polymer, more preferably less than 1 percent, preferably less than 0.1% by weight of a styling polymer, and optimally no styling polymer.

[0096] In hair treatment compositions containing a conditioning agent, it is preferred that a cationic polymer is also present.

[0097] Adjuvants The compositions of the present invention may also contain adjuvants suitable for hair care. Generally, such ingredients are included individually at a level of up to 2%, preferably up to 1% by weight of the total composition.

[0098] Among the suitable hair care adjuncts are: (i) Natural hair root nutrients such as amino acids and sugars. Examples of suitable amino acids include arginine, cysteine, glutamine, glutamic acid, isoleucine, leucine, methionine, serine and valine, and / or their precursors and derivatives. The amino acids may be added alone, as mixtures, or in the form of peptides, e.g., dipeptides and tripeptides. The amino acids may also be added in the form of protein hydrolysates, such as keratin or collagen hydrolysates. Suitable sugars are glucose, dextrose and fructose. These may be added alone or in the form of, for example, fruit extracts. A particularly preferred combination of natural hair root nutrients for inclusion in the composition of the present invention is isoleucine and glucose. A particularly preferred amino acid nutrient is arginine. (ii) Hair fibre benefit agents. Examples are ceramides to moisturise the fibre and maintain cuticle integrity. Ceramides are available by extraction from natural sources or as synthetic ceramides and pseudoceramides. A preferred ceramide is Quest's Ceramide II. Mixtures of ceramides may also be suitable, such as Ceramides LS, ex Laboratoires Serobiologiques.

[0099] Minor Ingredients The composition may also contain other ingredients to enhance performance and / or consumer acceptance. Such ingredients include fragrances (encapsulated or free, or both), colorants, dyes and pigments, pearlescent or opacifying agents, viscosity modifiers, stabilizers and preservatives. A suitable preservative system includes sodium benzoate and sodium salicylate, with sodium hydroxide and citric acid H2O to adjust pH. Alternative preservative systems that include formaldehyde include MIT and DMDM ​​hydantoin.

[0100] Product form The hair care composition may suitably be a shampoo, conditioner, spray, mousse, gel, wax or lotion. Particularly preferred product forms are hair treatment products such as shampoos, post-wash conditioners (leave-in and rinse-off) and hair essences. Rinse-off products are preferred, with shampoos being especially preferred.

[0101] Preferably, the composition is free or substantially free of hair styling polymers.The composition is preferably formulated as a composition for treating hair and subsequent rinsing.

[0102] A particularly preferred hair care composition is a shampoo composition. The total amount of surfactant in the shampoo composition of the present invention (including any co-surfactant and / or any emulsifier) ​​is generally from 5 to 30% by weight of the composition, preferably from 10 to 25% by weight, more preferably from 15 to 20% by weight. EXAMPLES

[0103] The invention will now be further described with reference to the following non-limiting examples.

[0104] Working Example A. Preparation of Capsules Capsules were prepared using the following materials, the details of the materials and preparation method are outlined below: [Table 1]

[0105] [Table 2]

[0106] Preparation method I The following solutions were prepared: Solution A: A solution of 0.4 g Mowiol 8-88 in 39.6 g demineralized water. Solution B: Piroctone (0.225 g), propyl benzoate (2.25 g) and isopherone diisocyanate (0.45 g). Solution C: 10% DETA in deionized water (1 mL).

[0107] Solution A was added to a 60 mL glass jar. Solution B was added to the jar followed by homogenization with an IKA Ultra Turrax T25basic at setting 1 for 2 minutes at 11,000 rpm (the jar itself was gently swirled during this time to aid in homogenization). Solution C was added dropwise with gentle stirring. The emulsion was gently stirred at room temperature for 1 hour followed by stirring at 35° C. for 5 hours before being cooled.

[0108] Preparation method II The following solutions were prepared: Solution A: A solution of 0.4 g Mowiol 8-88 in 39.6 g demineralized water. Solution B: Piroctone (0.225 g), propyl benzoate (2.25 g) and isopherone diisocyanate (0.45 g) Solution C: 10% DETA in deionized water (1 mL). Solution D: 2% taurine in deionized water (1 mL).

[0109] Solution A was added to a 60 mL glass jar. Solution B was added to the jar followed by homogenization with an IKA Ultra Turrax T25basic at setting 1 for 2 minutes at 11,000 rpm (the jar itself was gently swirled during this time to aid in homogenization). Solution C was added dropwise with gentle stirring. Solution D was added dropwise with gentle stirring. The emulsion was gently stirred at room temperature for 1 hour followed by 5 hours at 35° C. before being cooled.

[0110] B. Method for measuring capsule disintegration when dry A tightly packed film of capsules is formed and imaged wet using a microscope on bright field mode with cross polarizing filters, which gives a completely black image as light is not polarized by the crystals. Upon drying, the broken or crushed capsules release piroctone, which crystallizes and appears white. Binary analysis of these images gives the % coverage of white and black, which can be used to infer the proportion of collapsed capsules in the dry sample.

[0111] To perform this binary region analysis, the following program was run on ImageJ software. 1. Open the image 2. Image > Format > 8 bit 3. Check Processing > Binary > Options - Black Background 4. Image > Adjust > Threshold - (Ensure that the white and black areas correspond correctly to the polarization. 5. Edit / Select / Make Selection 6. Analysis measurement (displays white area in pixels) 7. White pixels / total pixels=decay%.

[0112] [Table 3]

[0113] These results indicate that the presence of taurine can reduce the collapse of microcapsules upon drying and therefore reduce the release of piroctone.

[0114] C. Method for measuring piroctone release from capsules in surfactant solution The following solutions were prepared: Solution A: Add 5 mL of water to 95 mL of methanol.

[0115] A calibration curve was generated: 0.0562 g of piroctone was dissolved in solution A in a 100 mL volumetric flask. Calibration curve samples were prepared by serial dilution in a 10 mL scale at concentrations of 56.2, 44.96, 33.72, 22.48, 11.24, 5.62, 2.81, and 1.40 μg / mL. The absorbance of each solution was measured at λmax=303 nm.

[0116] [Table 4]

[0117] The calibration curve was determined to be Abs300nm=0.03019[piroctone]-0.01003.

[0118] Capsule Leakage Measurement 1 mL of the microcapsule dispersion was taken immediately after synthesis and added to an 8 mL amber vial. To this, 5 mL of 1 w / w% TWEEN-40 solution was added and the vial was sealed for 48 hours. After 48 hours, the dispersion was filtered through a 0.45 μm PTFE syringe filter and 100 uL was added to 900 uL of Solution A.

[0119] The solution was analyzed by UV-Vis spectrophotometry at 303 nm using a Cary60 UV-Vis spectrophotometer. The absorbance results were converted to concentrations (mg / mL via a calibration curve not reported here) and the % leakage was obtained by dividing by the concentration of total piroctone (5.62 mg / mL).

[0120] [Table 5]

[0121] Example 2 Example 2 is a shampoo composition according to the present invention. [Table 6]

Claims

1. A core-shell microcapsule having a liquid core and a shell, the liquid core comprising a solvent and a dissolved piroctone compound; wherein the ratio of solvent to piroctone compound is at least 11:1; the shell comprises a polyurea containing taurine; isopherone diisocyanate and diethylenetriamine are used to form a polyurea, and taurine is present at a level of at least 0.1% by weight relative to the isopherone diisocyanate; Core-shell microcapsules.

2. The microcapsule of claim 1 , wherein the solvent comprises an aromatic compound.

3. 3. The microcapsule of claim 1 or 2, wherein the shell has a deposition aid grafted to its outer surface.

4. The microcapsule of claim 3 , wherein the deposition aid is a cationic polymer.

5. A microcapsule according to any one of claims 1 to 4, wherein the shell is prepared by interfacial polymerization.

6. A hair care composition comprising a surfactant and at least 0.05% by weight of the total composition of the core-shell microcapsules according to any one of claims 1 to 5.

7. A hair care composition according to claim 6, wherein the level of the piroctone compound is from 0.01 to 1.0% by weight of the total composition.

8. 8. The hair care composition of claim 6 or 7, wherein the hair care composition is an anti-dandruff shampoo.

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