COMPOSITE PARTICLE FOR HAIR CARE, METHOD FOR PREPARING SAID COMPOSITE PARTICLE AND HAIR CARE PRODUCT COMPRISING IT

Abstract

A composition comprising: (i) an anti-dandruff agent; (ii) a wax or wax-like substance in which said anti-dandruff agent is soluble or dispersible, wherein the melting point of said wax and said substance is from 30°C to 105°C and wherein said substance is not a UV-absorbing sunscreen; and (iii) a cationic polymer having a weight-average molecular weight of 10 3 Give 10 7 Where said composition is in the form of particles with a size of 0.1 to 1000 µm and where said wax-like substance is a fatty alcohol of C 13 a 35 ; wherein said wax is at least one of beeswax, china wax, lanolin, shellac wax, spermaceti, myrica cerifera wax, candelilla wax, carnauba wax, castor wax, esparto grass wax, Japan wax, ouricury wax, rice bran wax, soy wax, sebifera wax, ceresin wax, montana wax, ozocerite wax, and peat wax.

Description

DESCRIPTIVE MEMORANDUM Field of invention The present invention relates to hair care compositions comprising an anti-dandruff agent, more particularly piroctone olamine. Background of the invention The effectiveness of an anti-dandruff shampoo or conditioner depends largely on the amount of anti-dandruff agent deposited on the scalp and hair. Typically, at the point of use, the contact time between the hair / scalp and any hair care product is very short, for example, 10 to 120 seconds, and then the product is rinsed out. Therefore, the anti-dandruff agent may not have enough time to be deposited. Thus, within this limited contact time, it is desirable to deposit as much of the agent as possible. However, the deposition of any active ingredient, especially an anti-dandruff agent, through a hair care product presents a technical challenge, as some particles of the anti-dandruff agent tend to be washed away rather than deposited.To compensate for the loss, an increase in the amount of anti-dandruff agent is a possible solution, but it is neither technically sound nor economically viable. Piroctone olamine (Octopirox®) is a widely used anti-dandruff agent. However, insufficient deposition remains a technical problem. Another issue is its instability in shampoos. The document US20040213751 A1 (P&G) discloses a composition for the 1002616 of 39 hair care comprising pyrithione and a layered material containing zinc that provides a boost factor greater than 1. WO14124066 A1 (P&G) discloses hair care compositions comprising cationic polymers and anionic particles for improved pyrithione deposition. WO2008101546 (Rovi) discloses a cosmetic preparation with an active ingredient for the protection or treatment of the skin and / or hair and with a carrier material in which the active ingredient is bound or associated with the active ingredient, wherein the carrier material comprises a proportion of chitosan. The active substance bound or associated with a carrier material is a fraction having chitosan and a proportion of polylactide, polyglycolide and / or polylactide glycolide or their derivatives, and wherein the carrier material is in the form of particles having an average particle size of 10 to 1000 nm. WO10105922 A1 [Unilever] discloses a particle comprising a waxy solid and a polymer deposition adjuvant that generally has no cationic charge and a method for preparing said particle. Our pending application EP19154998 (Unilever) discloses composite particles comprising a photolabile anti-dandruff agent and an organic UV filter having a melting point of 30°C to 105°C, which is characterized in that said composite particles comprise a cationic polymer having a weight average molecular weight of 1000 Da to 10000000 Da. 1002616 of 39 Document WO9823258 A1 (Unilever) discloses a shampoo containing piroctone olamine and 0.1 to 5% by weight of polyethyleneimine to enhance the deposition of piroctone olamine. Summary of the invention It has been determined that at least some of the problems of the prior art can be solved by the present invention. According to a first aspect, a composition is disclosed that comprises: (i) an anti-dandruff agent; (ii) wax or a wax-like substance in which said anti-dandruff agent is soluble or dispersible, wherein the melting point of said wax and said substance is from 30°C to 105°C and wherein said substance is not a UV-absorbing sunscreen; and, (iii) a cationic polymer having a weight-average molecular weight of 103Da to 107 Da, wherein said composition is in the form of particles with a size of 0.1 to 1000 microns and wherein said wax-like substance is a C13 to C35 fatty alcohol; where said wax is at least one of beeswax, china wax, lanolin, shellac wax, spermaceti, myrica cerifera wax, candelilla wax, carnauba wax, castor wax, esparto grass wax, Japan wax, ouricury wax, rice bran wax, soy wax, sebifera wax, ceresin wax, montana wax, ozocerite wax, and peat wax. We have determined that the particles of the invention not only serve to 1002616 of 39 deposit more anti-dandruff agent on the scalp, but also stabilize the anti-dandruff agent, especially piroctone olamine, in a hair care product, such as a shampoo formulation. Such agents may lose their effectiveness over time, probably due to the presence of surfactants, polymers, and other ingredients that can degrade or destabilize the anti-dandruff agent. According to a second aspect, a method for preparing a composition according to claim 1 is disclosed, comprising the step of heating and stirring an aqueous suspension comprising said wax or wax-like substance and said anti-dandruff agent, followed by the step of adding said cationic polymer to said suspension and further heating said suspension for 5 to 60 minutes at 30 to 100 °C. According to a third aspect, a hair care product comprising a composition of the first aspect is disclosed. Detailed description of the invention For the avoidance of doubt, any feature of one aspect of the present invention may be used in any other aspect of the invention. The word "comprising" means that it includes, but not necessarily consists of or is composed of. In other words, the steps or options listed need not be exhaustive. It is noted that the examples given in the following description are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are 1002616 of 39 percent weight / weight, unless otherwise stated. Except in operational and comparative examples, or where explicitly stated otherwise, all numbers in this description and claims indicating quantities of material or reaction conditions, physical properties of materials and / or use are to be understood as modified by the word approximately. Numerical ranges expressed in the format x to y are understood to include x and y. When multiple preferred ranges are described for a specific characteristic in the format xay, it is understood that all ranges combining the different parameters are also included. As used herein, the indefinite article a / an and its corresponding definite article the / the means at least one, or one or more, unless otherwise specified.The various features of the present invention referred to in the preceding individual sections apply, as appropriate, to other sections mutatis mutandis. Accordingly, the features specified in one section may be combined with the features specified in other sections as appropriate. The section headings are added because it is considered appropriate and are not intended to limit disclosure. “Hair care product,” as used herein, means a composition for topical application to the hair or scalp of mammals, especially humans. Topical means that the product is applied to the external surface of the body. In the present invention, this is achieved by applying the hair care product to the hair or scalp. Such a product may generally be classified as a 1002616 of 39 composition that is left on or rinsed out, and includes any product applied to improve the appearance, cleanliness, odor control, or overall aesthetics of the scalp and hair. The hair care product of the present invention is preferably a leave-in product. Alternatively, the hair care product of the present invention is a rinse-out composition. A hair care product according to the present invention is preferably a shampoo, hair conditioner, hair cream, hair colorant, hair serum, hair gel, or hair oil. In one aspect, the composition of the invention comprises: (i) an anti-dandruff agent; (ii) wax or a wax-like substance in which said anti-dandruff agent is soluble or dispersible, wherein the melting point of said wax and said substance is from 30°C to 105°C and wherein said substance is not a UV-absorbing sunscreen; and, (iii) a cationic polymer having a weight-average molecular weight of 103Da to 107 Da, wherein said composition is in the form of particles with a size of 0.1 to 1000 microns and wherein said wax-like substance is a C13 to C35 fatty alcohol; where said wax is at least one of beeswax, china wax, lanolin, shellac wax, spermaceti, myrica cerifera wax, candelilla wax, carnauba wax, castor wax, esparto grass wax, Japan wax, ouricury wax, rice bran wax, soy wax, sebifera wax, ceresin wax, montana wax, ozocerite wax, and peat wax. 1002616 of 39 The term "particles" means particles ranging in size from 0.1 to 1000 µm, preferably from 0.1 to 100 µm, and much more preferably from 1 to 50 µm. Preferably, the composition of the invention is in powder form or in the form of an aqueous suspension. This composition preferably contains from 1 to 90% by weight of particles, the remainder being water. Alternatively, the composition of the invention, i.e., the particles are in powder form, preferably a freeze-dried powder. The size can be measured, for example, by laser diffraction using a system (such as a Mastersizer™ 2000 available from Malvern Instruments Ltd). It is preferred that the ratio of the amount of anti-dandruff agent to the amount of said wax or wax-like substance in said microparticles be from 1:0.01 to 1:1000 parts by weight. It is preferred that the microparticles comprise from 0.1 to 80% by weight of anti-dandruff agent, from 18 to 95% by weight of wax or wax-like substance, and from 0.5 to 10% by weight of cationic polymer. Wax or wax-like substance The composition of this invention comprises a wax or wax-like substance in which the anti-dandruff agent is soluble or dispersible, wherein the melting point of the wax and the substance is from 30°C to 105°C. The wax-like substance is not a sunscreen that absorbs UV rays. 1002616 of 39 The melting point refers to the temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. The wax of the invention is at least one of beeswax, china wax, lanolin, shellac, spermaceti, myrica cerifera wax, candelilla wax, carnauba wax, castor wax, esparto grass wax, Japan wax, ouricury wax, rice bran wax, soybean wax, sebifera wax, ceresin wax, montana wax, ozocerite wax, and peat wax. Such waxes are often selected from hydrocarbon waxes and ester waxes, which may be derived from natural sources or synthesized. Suitable hydrocarbon waxes include mineral wax, microcrystalline wax, montana wax, and low molecular weight polyethylene, such as 300 to 600 daltons. Suitable ester waxes can be derived from natural unsaturated oils, such as vegetable triglyceride oils, by hydrogenation and optionally dehydroxylation (where the substituent contains at least one hydroxyl group as in castor oil).Suitable ester waxes include castor wax, candelilla wax, carnauba wax, beeswax, and spermaceti wax. Natural waxes such as beeswax encompass a range of different chemical classes. Synthetic esters often comprise aliphatic monoesters containing at least 30 carbon atoms and may, in fact, be isolated natural products like beeswax, be derived from them, or be the same compounds. The wax-like substance of the present invention is a C13-35 fatty alcohol. 1002616 of 39 One or a mixture of fatty alcohols may be used. Preferred fatty alcohols include cetostearyl alcohol, cetyl alcohol, stearyl alcohol, eicosyl alcohol, and behenyl alcohol. Commercial fatty alcohols, although nominally and predominantly one specified alcohol, often comprise a minor fraction, such as up to 5 or 6% by weight, of homologs that differ by 2, 4, or even 6 carbons. Wax and wax-like substances are not sunscreens that absorb UV rays. For example, some sunscreens are listed below: 2-hydroxy-4-methoxybenzophenone (also known as Benzophenone-3 CAS: 131-57-7, MP 62 at 64°C), 2,2-dihydroxy-4methoxybenzophenone (CAS: 131-53-3, MP 73 at 75°C), butylmethoxydibenzoylmethane (CAS: 70356-09-1, MP 81 at 84°C), bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S, CAS: 187393-00-6, MP 83-85°C), menthyl anthranilate (CAS: 134-09-8, MP 62.5-63.5°C), 4-methylbenciliden camphor (Enzacamene) (CAS: 36861-47-9, MP 66 at 69°C), benzophenone-7 (5-chloro-2-hydroxybenzophenone) (CAS: 85-19-8, MP 96 at 98°C), Benzophenone-8 (dioxybenzone) (CAS: 131-53-3, MP 68°C), benzophenone10 (mexenone, 2-hydroxy-4-methoxy-4'-methyl-benzophenone, CAS: 1641-17-4, MP 99 to 102°C), benzophenone-12 (octabenzone) (CAS: 1843-05-6, MP 47 to 49°C). Anti-dandruff agent The composition of the invention, i.e., the microparticles, preferably comprise from 0.1 to 80% by weight, preferably from 0.2 to 40% by weight, and more preferably from 0.25 to 15% by weight of the anti-dandruff agent. Anti-dandruff agents are compounds that are active against dandruff and are normally 1002616 of 39 antimicrobial agents, preferably antifungal agents. Antidandruff agents normally show a minimum inhibitory concentration of approximately 50 mg / ml or lower against Malassezia. The preferred anti-dandruff agent is piroctone olamine, climbazole, selenium sulfide, zinc pyrithione, or zinc sulfate. Cationic polymer The compositions of the invention also comprise a cationic polymer. Preferably, the polymer is polyamine, polyvinylpyrrolidone, polylysine, protamine, trimethylammonium ethyl (meth)acrylate homopolymer and copolymer, trimethylammonium acrylate homopolymer and copolymer, dialkyldialylammonium halide homopolymer and copolymer, chitosan or derivatized chitosan, cellulose or its derivatives comprising trimethylammonium-substituted epoxide, trimethylammonium hydroxypropyl starch halide, polyethyleneimines, or polycondensates containing diquaternary ammonium or polyquaternary ammonium repeating units. The term cationic polymer is used to distinguish such polymers from anionic polymers, i.e., negatively charged polymers, as well as from non-ionic polymers, i.e., polymers that lack any charge. The molecular weight of the cationic polymer is preferably from 30,000 to 1,000,000 Daltons, more preferably from 70,000 to 600,000 Daltons, and even more preferably from 150,000 to 400,000 Daltons. 1002616 of 39 The zeta potential is the charge that develops at the interface between a solid surface and its liquid medium. This potential, measured in millivolts, can arise through various mechanisms. These include the dissociation of ionogenic groups on the particle surface and the differential adsorption of ions from solution in the surface region. The net charge on the particle surface affects the ion distribution in the surrounding region, increasing the concentration of counterions near the surface. Therefore, an electrical double layer forms in the particle-liquid interface region. Thus, the zeta potential is a function of the particle's surface charge, any adsorbed layers at the interface, and the nature and composition of the surrounding suspension medium.The zeta potential can be determined experimentally, and since it reflects the effective charge on the particles and is therefore related to the electrostatic repulsion between them, it has proven to be extremely relevant for the practical study and control of colloidal stability and flocculation processes. A variety of methods and instruments are available for its measurement with a reasonable degree of accuracy. For example, the zeta potential of particles is measured using a Malvern Nano ZS90 instrument in DI water with a solids content of 50 ppm and a pH of 7 at 25°C. The zeta potential of the cationic polymer is preferably from +10 to +100 mV. It is particularly preferred that the polymer be chitosan. It is preferred that the chitosan comprise a chitosan component and an anion. It is also preferred that the chitosan be a salt of chitosan and an amino acid. Preferably, the amino acid comprises glutamine, glutamic acid, histidine, leucine, lysine, serine, threonine, arginine, or a mixture thereof, most preferably arginine. 1002616 of 39 Preferably, chitosan comprises at least 5%, more preferably at least 10% of protonated primary amino group per mole of the total amount of primary amino group and protonated primary amino group. It is preferred that the degree of deacetylation of chitosan be at least 65%, more preferably 70 to 95%, even more preferably 72 to 90%, and much more preferably 75 to 85%. It is preferred that the ratio of the anti-dandruff agent to the cationic polymer in said microparticles be from 1:0.01 to 1:1000 parts by weight. It is preferred that the compositions of the invention, i.e., the particles, comprise a co-solvent in which the anti-dandruff agent is soluble or dispersible, wherein the co-solvent is a ketone and wherein the co-solvent is not wax or a wax-like substance. This co-solvent is in addition to the wax or wax-like substance. It is preferred that said co-solvent be a ketone selected from 2-hexanone or 2-octanone or damascone. More preferably, this ketone is damascone. Method for preparing composite particles According to a second aspect, a method is disclosed for preparing a composition of the first aspect, which comprises the step of heating and stirring a 1002616 of 39 aqueous suspension comprising said wax or wax-like substance and said anti-dandruff agent, followed by the step of adding said cationic polymer to said suspension and further heating said suspension for 5 to 60 minutes at 30 to 100 °C. Hair care formula According to a third aspect, a hair care product comprising a composition of the first aspect is disclosed. More preferably, the hair care product comprises an amount of the composition (i.e., microparticles) such that the total amount of the anti-dandruff agent in said hair care product is from 0.01 to 5.0% by weight. Ideally, the hair care product is a shampoo, hair conditioner, hair cream, hair colorant, hair serum, hair gel, or hair oil. In addition to the anti-dandruff agent present in the form of composite particles, the hair care compositions according to the invention may also comprise an additional anti-dandruff agent, which, for example, may be the same as that found within the microparticles. When present, the hair care compositions of the invention preferably comprise from 0.05 to 5% by weight of the additional anti-dandruff agent. The additional anti-dandruff agent is preferably selected from azoles, 1002616 of 39 Octopirox® (piroctone olamine), selenium sulfide, salicylic acid and combinations thereof. Azoles include ketoconazole and climbazole, preferably climbazole. The hair care compositions of the invention may further comprise a zinc salt. The additional zinc salt may be suitably selected from zinc salts of organic acids, zinc salts of inorganic acids, zinc oxides, zinc hydroxides, or a mixture thereof. Examples of preferred zinc salts include zinc oxide, zinc pyrrolidone carboxylic acid, zinc citrate, zinc carbonate, zinc chloride, zinc sulfate, zinc glycinate, zinc acetate, zinc lactate, and mixtures thereof. If present, the hair care compositions of the invention preferably comprise 0.1 to 5% by weight, preferably 0.2 to 3% by weight, and more preferably 0.25 to 2.5% by weight of the salt based on the total weight of the composition. The hair care compositions of the present invention comprise a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, zwitterionic surfactants, and mixtures thereof. The nature, type, quantity, and specific combinations that may be used depend on the formulation of the composition and will depend largely on whether it is a shampoo, a conditioner, or a shampoo-conditioner. 1002616 of 39 Preferably, the hair care product of the invention is a shampoo. Preferably, this comprises a surfactant that is sodium lauryl sulfate, sodium lauryl ether sulfate, sodium lauryl ether sulfosuccinate, ammonium lauryl sulfate, ammonium lauryl ether sulfate, sodium cocoyl isethionate and lauryl ether carboxylic acid, coco betaine, cocamidopropyl betaine, sodium cocoamphoacetate, or a mixture thereof. Preferably, the hair care product of the present invention comprises from 1 to 50%, preferably from 2 to 40%, more preferably from 4 to 25% of total surfactant. Furthermore, it is preferred that the hair care product of the invention comprise a cosmetic ingredient.Preferably, the cosmetic ingredient is selected from the group consisting of a silicone, an antibacterial agent other than anti-dandruff agents, a foam booster, a perfume, encapsulants (e.g., an encapsulated fragrance), a dye, a coloring agent, a pigment, a preservative, a thickener, a protein, a phosphate ester, a buffering agent, a pH adjusting agent, a pearlescent (e.g., mica, titanium dioxide, titanium dioxide-coated mica, ethylene glycol distearate (INCI glycol distearate)) and / or opacifier, a viscosity modifier, an emollient, a sunscreen, an emulsifier, an active substance (e.g., menthol and menthol derivatives), vitamins, mineral oils, essential oils, lipids, natural actives, glycerin, natural hair nutrients such as botanical extracts, fruit extracts, sugar derivatives and amino acids, microcrystalline cellulose and mixtures thereof. 1002616 of 39 Preferably, the hair care product of the present invention includes from 0.01 to 20% by weight of at least one cosmetic ingredient, more preferably from 0.05 to 10% by weight, even more preferably from 0.075 to 7.5% by weight and much more preferably from 0.1 to 5% by weight of at least one cosmetic ingredient, in the total weight of the product. The hair care product of the present invention may also comprise synergistic antimicrobial compounds that provide a synergistic antimicrobial benefit when used in combination with the anti-dandruff active ingredient (e.g., zinc pyrithione) to enhance its properties and further inhibit the growth of Malassezia furfur. Non-restrictive examples of such compounds include compounds having alcohol groups (e.g., honokiol, magnolol, or paeonol), piperazines, and a phenolic compound found in natural plant extracts, namely thymol and terpeniol. The hair care product may also contain a vitamin B3 compound. The preferred vitamin B3 compound is niacinamide. Niacinamide is known for stimulating the secretion of antimicrobial proteins (AMPs) from keratinocytes. These secreted AMPs enhance the immunity of areas such as the scalp. Therefore, with the use of niacinamide, the effectiveness of dandruff treatments can be improved not only through antifungal activity but also by strengthening the scalp's own protective barrier against germs. This combination 1002616 of 39 could provide longer lasting protection, for example, up to 24 hours of protection against germs. When present, it is preferred that the hair care compositions of the invention comprise from 0.1 to 5% niacinamide, more preferably from 0.5 to 5%, more preferably from 0.5 to 3%, and optimally from 1.0 to 3.0% by weight of the composition. Silicone It is preferred that the hair care product of the invention comprise silicone. For example, the compositions of the invention may contain emulsified droplets of a silicone conditioning agent, to improve the conditioner's performance. Suitable silicones include polydiorganosiloxanes, polydimethylsiloxanes designated CTFA dimethicone. Additionally, polydimethylsiloxanes with terminal hydroxyl groups, designated CTFA dimethiconol, are suitable for use in the compositions of the invention (particularly shampoos and conditioners). Preferably, the viscosity of the emulsified silicone is at least 10,000 cst at 25°C, the viscosity of the silicone is preferably at least 60,000 cst, much more preferably at least 500,000 cst, ideally of 1002616 of 39 at least 1,000,000 cst. Preferably the viscosity does not exceed 109 cst to facilitate formulation. Examples of suitable preformed emulsions include Xiameter MEM 1785 and DC2-1865 microemulsion, available from Dow Corning. These are dimethiconol emulsions / microemulsions. Crosslinked silicone gums are also available in a preemulsified form, which is advantageous for simplifying formulation. An additional preferred class of silicones for inclusion in shampoos and conditioners are amino-functional silicones. An amino-functional silicone is defined as a silicone containing at least one primary, secondary, or tertiary amine group, or one quaternary ammonium group. Examples of suitable amino-functional silicones include polysiloxanes designated CTFA amodimethicone. Specific examples of amino functional silicones suitable for use in the invention are aminosilicone oils DC2-8220, DC2-8166 and DC28566 (all from Dow Corning). It is preferred that the total amount of silicone be from 0.01 to 10% by weight, more preferably from 0.1 to 5% by weight and much more preferably from 0.5 to 3% by weight. pH of compositions It is preferred that the pH of the hair care product of the present invention be from 3 to 7, more preferably from 4 to 7, or even lower 1002616 of 39 preferably from 4 to 6.5, much more preferably from 4.2 to 6.5. Shampoos When the hair care product of the invention is a shampoo, it is generally aqueous, i.e., it has water or an aqueous solution or a lyotropic liquid crystalline phase as its main component. Ideally, the composition of shampoo comprises 50 to 98%, preferably 60 to 92%, of water. Preferably, the shampoo composition comprises one or more cationic polymers to condition the hair. Suitable cationic polymers include homopolymers that are cationically substituted or can be formed from two or more types of monomers. The weight-average molecular weight (Mw) of the polymers will generally be between 100,000 and 3 million Daltons. The polymers will have groups containing cationic nitrogen, such as quaternary ammonium or protonated amino groups, or a mixture thereof. If the polymer's molecular weight is too low, the conditioning effect will be poor. If it is too high, high extensional viscosity problems may arise, leading to stiffness in the composition when poured. The group containing cationic nitrogen will generally be present as a substituent in a fraction of all monomeric units of the 1002616 of 39 cationic polymer. Therefore, when the polymer is not a homopolymer, it may contain non-cationic spacer monomeric units. Such polymers are described in the CTFA Cosmetic Ingredient Directory, 3rd edition. The ratio of cationic to non-cationic monomeric units is selected to give polymers that have a cationic charge density in the required range, which is generally 0.2 to 3.0 meq / g. The cationic charge density of the polymer is appropriately determined by the Kjeldahl method as described in the United States Pharmacopeia under Chemical Tests for the Determination of Nitrogen. Suitable cationic polymers include copolymers of vinyl monomers having cationic amine or quaternary ammonium functional groups with water-soluble spacer monomers such as (meth)acrylamide, alkyl and dialkyl (meth)acrylamides, alkyl (meth)acrylate, vinyl caprolactone, and vinyl pyrrolidine. The alkyl- and dialkyl-substituted monomers preferably have C1-C7 alkyl groups, more preferably C1-3 alkyl groups. Other suitable spacers include vinyl esters, vinyl alcohol, maleic anhydride, propylene glycol, and ethylene glycol. Cationic amines can be primary, secondary, or tertiary amines, depending on the specific species and the pH of the composition. Secondary and tertiary amines are generally preferred, especially tertiary amines. Amine-substituted vinyl monomers and amines can be polymerized in amine form and then converted to ammonium by quaternization. 1002616 of 39 Cationic polymers may comprise mixtures of monomeric units derived from amines and / or monomers substituted with quaternary ammonium and / or compatible spacer monomers. Suitable cationic polymers (non-restrictive examples) include: - cationic polymers containing diallyl and quaternary ammonium, including, for example, dimethyldiallylammonium chloride homopolymer and acrylamide and dimethyldiallylammonium chloride copolymers, referred to in the industry (CTFA) as Polyquaternium 6 and Polyquaternium 7, respectively; - mineral acid salts of aminoalkyl esters of homopolymers and copolymers of unsaturated carboxylic acids having 3 to 5 carbon atoms, (as described in U.S. Patent 4,009,256); - cationic polyacrylamides (as described in document WO95 / 22311). Other cationic polymers that can be used include cationic polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives. A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic derivative of guar gum, such as guar hydroxypropyltrimethylammonium chloride (commercially available from Rhodia under its JAGUAR brand name). Examples of such materials are JAGUAR C13S, JAGUAR C14, and JAGUAR C17. 1002616 of 39 Mixtures of any of the above cationic polymers can be used. It is preferred that the hair care product of the invention comprise from 0.01 to 5%, preferably from 0.02 to 1%, more preferably from 0.05 to 0.8% of cationic polymer. The hair care product of the invention may further comprise a cationic deposition polymer that is a cationic polygalactomannan having an average molecular weight (Mw) of 1 million to 2.2 million g / mol and a cationic degree of substitution of 0.13 to 0.3. Polygalactomannans are polysaccharides composed primarily of galactose and mannose units and are generally found in the endosperm material of leguminous plant seeds such as guar, carob, honeysuckle, flame tree, and other members of the Leguminosae family. Polygalactomannans consist of a backbone of β-D-mannopyranosyl units linked in a 1⁴-linked manner (also called mannoside units or residues) with α-D-galactosyl side groups linked in a 1⁶-linked manner (also called galactoside units or residues) branching off from carbon atom number 6 of a mannopyranose residue in the polymer backbone. Polygalactomannans from different Leguminosae species differ in the frequency of occurrence of the galactoside side units branching off the polymannoside backbone. The 1002616 of 39 and galactoside are referred to generically herein as glycoside units or residues. The average ratio of mannoside to galactoside units in the polygalactomannan contained in guar gum (hereafter referred to as guar) is approximately 2:1. Suitable cationic polygalactomannans include guar and hydroxyalkyl guar (e.g., hydroxyethyl guar or hydroxypropyl guar), which has been cationicly modified by chemical reaction with one or more bypass agents. In a typical composition, the amount of cationic polygalactomannans will generally range from approximately 0.05 to 1%, preferably from 0.1 to 0.8%, more preferably from 0.2 to 0.6% by weight of the composition. The hair care product of the invention may further comprise an anionic polymer rheology modifier such as a carboxylic acid polymer. The term carboxylic acid polymer in the context of this invention generally denotes a homopolymer or copolymer obtained from the polymerization of ethylenically unsaturated monomers containing dangling carboxylic acid groups (hereafter referred to as carboxylic monomers). Suitable carboxylic monomers generally have one or two carboxylic acid groups, a carbon-carbon double bond, and contain a 1002616 of 39 total of 3 to approximately 10 carbon atoms, more preferably 3 to approximately 5 carbon atoms. Specific examples of suitable carboxylic monomers include α-β-unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; and α-β-unsaturated dicarboxylic acids such as itaconic acid, fumaric acid, maleic acid, and aconitic acid. Salts, esters, or anhydrides of the mono- or α-β-unsaturated dicarboxylic acids described above can also be used. Examples include half-esters of α-β-unsaturated dicarboxylic acids with C1-4 alkanols, such as monomethyl fumarate; cyclic anhydrides of α-β-unsaturated dicarboxylic acids such as maleic anhydride, itaconic anhydride, and citraconic anhydride; and esters of acrylic acid or methacrylic acid with C1-30 alkanols, such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, hexadecyl acrylate and octadecyl acrylate. Optionally, other ethylenically unsaturated monomers may be copolymerized into the carboxylic acid polymer backbone. Examples of other ethylenically unsaturated monomers include styrene, vinyl acetate, ethylene, butadiene, acrylonitrile, and mixtures thereof. The carboxylic acid polymers preferably have a molecular weight of at least 1 million Daltons. Suitable examples include crosslinked copolymers polymerized from C1-4 alkyl acrylate or methacrylate (e.g., ethyl acrylate) with one or 1002616 of 39 plus selected comonomers of acrylic acid, methacrylic acid, and mixtures thereof. In general, such materials may be referred to by the INCI name Acrylates Copolymer. Commercially available examples include Aculyn® 33 from Rohm and Haas. Crosslinked copolymers polymerized from C10-30 alkyl esters of acrylic or methacrylic acid with one or more comonomers selected from acrylic acid, methacrylic acid, and their respective C1-4 alkyl esters are also suitable. Such materials can generally be referred to by the INCI name Acrylates / C10-30 Alkyl Acrylate Crosspolymer. Commercially available examples include Carbopol® 1342 and 1382 polymers from Lubrizol Advanced Materials. Crosslinked copolymers of acrylic acid or methacrylic acid with alkyl acrylates and ethoxylated hydrophobic modified alkyl acrylates are also optionally suitable. Such materials can generally be referred to by the INCI names Acrylates / Methacrylate Steareth-20 Copolymer, Acrylates / Methacrylate Beheneth-25 Copolymer, Acrylates / Steareth-20 methacrylate crosspolymer and acrylates / Palmeth-25 acrylate copolymer. Commercially available examples include Aculyn® 22, 28 or 88 from Rohm & Haas and Synthalen® from 3V Sigma. It is preferred that the carboxylic acid be a carbomer, such as acrylic acid homopolymers crosslinked with a pentaerythritol allyl ether or a sucrose allyl ether. 1002616 of 39 Mixtures of any of the materials mentioned above can also be used. Preferably, the hair care product of the invention comprises from 0.1 to 3.0%, more preferably from 0.4 to 1.5% of carboxylic acid polymer by weight of the composition. In formulations containing anionic polymer rheology modifiers, such as the carboxylic acid polymers described above, it is often necessary to neutralize at least a portion of the free carboxyl groups by adding an inorganic or organic base. Examples of suitable inorganic or organic bases include alkali metal hydroxides (e.g., sodium or potassium hydroxide), sodium carbonate, ammonium hydroxide, methylamine, diethylamine, trimethylamine, monoethanolamine, triethanolamine, and mixtures thereof. The hair care product of the invention may also comprise a non-ionic polymeric rheology modifier selected from one or more non-ionic cellulose ethers. Suitable nonionic cellulose ethers or their use as nonionic polymeric rheology modifiers in the invention include (C1-3 alkyl)cellulose ethers, such as methylcellulose and ethylcellulose; hydroxy(C1-3 alkyl)cellulose ethers, such as hydroxyethylcellulose and hydroxypropylcellulose; mixed hydroxy(C1-3 alkyl)cellulose ethers, such as hydroxyethylhydroxypropylcellulose; and ethers 1002616 of 39 of (alkyl C1-3 ) hydroxy (alkyl C1-3 ) cellulose, such as hydroxyethyl methylcellulose and hydroxypropyl methylcellulose. The preferred nonionic cellulose ethers for use as the nonionic polymer rheology modifier in the invention are water-soluble nonionic cellulose ethers such as methylcellulose and hydroxypropyl methylcellulose. The term "water-soluble" in this context denotes a water solubility of at least 1 gram, more preferably at least 3 grams, and much more preferably at least 5 grams in 100 grams of distilled water at 25°C and 1 atmosphere. This level indicates the production of a macroscopically isotropic or transparent, colorless or colored solution. Methylcellulose and hydroxypropyl methylcellulose are commercially available in various viscosity grades from Dow Chemical as the registered trademark METHOCEL®. Mixtures of any nonionic cellulose ether may also be suitable. In a typical composition according to the invention, the level of nonionic cellulose ethers will generally range from approximately 0.01 to approximately 2.0%, and preferably from 0.1 to 0.5%, more preferably from 0.1 to 0.3%, by weight based on the total weight of the composition. Preferably, the hair care product of the invention comprises 0.1 to 0.3% by weight of non-ionic cellulose ether. 1002616 of 39 The hair care product of the invention may contain additional optional ingredients to enhance performance and / or consumer acceptability. Examples of such ingredients include fragrances, dyes, pigments, and preservatives. Each of these ingredients will be present in an amount effective to achieve its purpose. Typically, these optional ingredients are included individually at a level of up to 5% by weight based on the total weight of the composition. How to use The hair care product of the invention is primarily intended for topical application to the hair and scalp. When the hair care product is shampoo, it is applied topically to the hair and then massaged into the hair and scalp. It is then rinsed out with water before drying the hair. A hair oil or hair serum, on the other hand, is a hair care product that is left on for 1 to 10 hours after application before washing. The invention shall further be illustrated by the following non-restrictive examples, in which all percentages quoted are by weight based on the total weight, unless otherwise indicated. The invention is not limited to the embodiments illustrated in the drawings. Therefore, it should be understood that when the features mentioned in the claims are followed by reference numbers, those numbers 1002616 of 39 are included solely for the purpose of enhancing the understandability of the claims, and in no way limit the scope of the claims. The examples are intended to illustrate the invention and are not intended to limit it to those examples per se. Examples Example 1: Preparation of a composition (microparticles) outside the invention (Ref. 1) One gram of Octopirox® was dissolved in 12.5 g of molten cetostearyl alcohol to form a clear solution at 70°C. Subsequently, 86.5 g of DI water were placed in a 250 mL beaker and heated to 70°C with stirring. The Octopirox® solution in cetostearyl alcohol was added to the water under homogenization at 2000 rpm for 15 minutes. The system was gradually cooled to room temperature with stirring. The evaporated water was then topped up until 100 g of suspension remained (13.5% solids content, i.e., microparticles). The particle size of the microparticles was 70 µm. Example 2: Preparation of a composite material within the invention (Ref.2) Three grams of chitosan were dissolved in 300 ml of 0.5% aqueous acetic acid to form a 1% chitosan solution. One gram of Octopirox® was dissolved in 12.5 g of molten cetostearyl alcohol to form a clear solution at 70°C. Then, 62.5 g of the 1% chitosan acetate solution and 24 39 g of water (DI) were placed in a beaker at 70°C. The Octopirox® solution was heated to 70°C and added to the contents of the beaker under homogenization at 2000 rpm for 15 minutes. The system was gradually cooled to room temperature under stirring. The evaporated water was then topped up until 100 g of suspension remained (14% solids content, i.e., microparticles). The particle size of the microparticles was 54 µm. Example 3: Preparation of a composite material within the invention (Ref. 3) A 1% chitosan acetate solution was prepared as described above. One gram of Octopirox® was dissolved in 12.5 g of molten cetostearyl alcohol and 4 g of damascone to form a clear solution at 70°C. Next, 62.5 g of 1% chitosan acetate solution and 20 g of DI water were mixed in a beaker at 70°C. The Octopirox® solution was heated to 70°C and added to the contents of the beaker under homogenization at 2000 rpm for 15 minutes. The system was gradually cooled to room temperature under stirring. The evaporated water was then topped up until 100 g of aqueous suspension remained (18% solids content, i.e., microparticles). The particle size of the microparticles was 43 pm. Example 4: Preparation of a composite material within the invention (Ref. 4) 1002616 of 39 A 1% chitosan acetate solution was prepared as described above. One gram of Octopirox® was dissolved in 8.5 g of molten cetostearyl alcohol and 4 g of damascone to form a clear solution at 70°C. Next, 62.5 g of the 1% chitosan solution and 24 g of DI water were mixed in a beaker and heated to 70°C. The Octopirox® solution was heated to 70°C and added to the beaker under homogenization at 2000 rpm for 15 minutes. The system was gradually cooled to room temperature under stirring. The evaporated water was then topped up until 100 g of suspension remained (14% solids content, i.e., microparticles). The particle size of the microparticles was 36 µm. The details of the compositions in Examples 1 to 4 are summarized in the Table 1. Table 1 Example / % by weight Octopirox® Cetostearyl alcohol Damascone Chitosan 1 7.4 92.6 — — 2 7.1 88.5 — 4.4 3 5.5 69.0 22.1 3.4 4 7.1 60.2 28.3 4.4 The compositions in Examples 1 to 4 were subjected to a variety of 1002616 of 39 tests described below. Example 5: Deposition Efficiency The degree of deposition (on the scalp) of Octopirox® contained in the microparticles was evaluated by formulating a series of shampoo compositions 1A to 4A, each of which comprises a fixed amount of the microparticles from Examples 1 to 4. In other words, shampoo 1A contained microparticles from Example 1 and so on. The formulations are shown in Table 2. Table 2 Ingredients / % by weight Reference Example No. 1A 2A 3A 4A 5 Octopirox® - - - - 0.2 Example 1 20 - - - - Example 2 - 20 - - - Example 3 - - 20 - - Example 4 - - - 20 - SLES (70%) 17.0 CAPB (30%) 5.0 Sodium Chloride 1.0 The degree of Octopirox® deposition on the scalp was determined as follows: 1002616 of 39 A sample of skin (2 cm x 2 cm x 4 mm) was placed in a Petridish® container, to which 375 mg of the shampoo under evaluation had been added. This sample and a blank (untreated) sample were immersed in 10 ml of methanol and dispersed with 10 minutes of ultrasonic treatment. One ml of the methanolic solution was passed through a 0.2 μm PTFE filter and transferred to a liquid chromatography (LC) sample vial for LC analysis to obtain data on the amount of D0 deposition. A sample of skin (2 cm x 2 cm x 4 mm) was placed in a Petridish® container, to which 375 mg of the shampoo under evaluation had been added. This sample was gently rubbed with another (untreated) sample for 30 seconds, and both samples were rinsed with 250 ml of water. The rinsed samples were then immersed in 10 ml of methanol and dispersed with 10 minutes of ultrasonic treatment. One ml of the methanolic solution was passed through a 0.2 μm PTFE filter and transferred to a liquid chromatography (LC) sample vial for LC analysis to obtain data on the amount of deposition (D). The deposition efficiency was calculated using the following equation: Octopirox deposition efficacy = D / Do x 100% The data are summarized in Table 3. Table 3 Reference sample number % of deposition 1002616 of 39 Example 5 1.9 Example 1A 9.4 Example 2A 31.1 Example 3A 28.3 Example 4A 22.1 The data in Table 3 indicate that the % deposition provided by a composition (microparticles) outside the invention (Example 5 and 1A) is not as good as the degree of deposition observed in the case of Examples 2A-4A. Example 6: The objective of this experiment was to determine the stability of Octopirox® contained in the microparticles of Examples 1 to 4 in a shampoo composition. This was assessed by verifying how much Octopirox® contained within the microparticles leached into the shampoo base. For this test, shampoo products 5 and 1A to 4A were used immediately after preparation. The test was repeated after storing the compositions for 1 day, 7 days, and 14 days. For this experiment, the shampoo products were prepared by mixing four grams of the microparticle suspension (Examples 1 to 4, as applicable) with 16 g of a shampoo base in 50 ml centrifuge tubes. Therefore, the shampoo formulations for the purpose of this experiment were different from the published formulations (1A to 4A). 1002616 of 39 in Table 2. To avoid confusion with nomenclature, the reference sample numbers used for this experiment were labeled 1B to 4B. The shampoo samples were stored at room temperature for 1 day, 7 days, and 14 days. At the predetermined time, 20 g of deionized water were added to the centrifuge tube (containing 20 g of shampoo), and the tubes were centrifuged at 10,000 rpm for 20 minutes. The liquid portion (supernatant) was then collected for UV analysis to determine the concentration of Octopirox®, which is represented as the percentage loss compared to the amount of Octopirox® in a freshly prepared shampoo product. The results are summarized in Table 4. Table 4 Reference Sample No. Octopirox® Leakage / Loss 1 day 7 days 14 days 1B 90.0 100.0 — 2B 35.1 78.2 100.0 3B 15.4 45.6 70.4 4B 17.4 38.9 40.8 The data in Table 4 indicate that Octopirox was more stable in compositions 2B to 4B. However, among these three, stability was 1002616 out of 39, the highest in the case of Example 4B. The microparticles in Example 4 contained a co-solvent (damascene) and this additional stability (or reduced leakage) can be attributed to the damascene. Example 7: Release of Octopirox® from microcapsules into sebum For this experiment, the suspension from Example 4 was lyophilized to obtain a powder. Seven (7) mg of this powder were incubated in 2 mL of a model tallow composition in an oven maintained at 32°C. At a predetermined time, the mixture was removed from the oven and passed through a 0.2 μm PTFE filter to remove any insoluble matter. The filtrate was dispersed in methanol and transferred to an LC sample vial for LC analysis. An additional 7 mg of the same powder was dissolved directly in methanol, and the Octopirox® concentration was measured by LC. This sample served as a control and was intended for 100% release. The percentage release of Octopirox® from the compound was then calculated. The results showed that approximately 90% of Octopirox® was released from the compound of Example 4 into the sebum at 32°C. In other words, this observation indicates that a compound according to the invention is sufficiently stable within the composition, but at the same time the compound can release Octopirox® when it comes into contact with sebum, and this property makes it suitable for use in hair care products, such as shampoo. Example 8 1002616 of 39 A 1% chitosan acetate solution was prepared as described above. One gram of Octopirox® was dissolved in 8.5 g of molten lauryl alcohol (MP 24°C) and 4 g of damascone to form a clear solution at 40°C. Next, 62.5 g of chitosan acetate solution and 24 g of DI water were measured into a beaker at 40°C. Octopirox® solution was heated to 40°C and added to the beaker under homogenization at 2000 rpm for 15 minutes. The system was gradually cooled to room temperature under stirring. Subsequently, the evaporated water was added to obtain 100 g of an aqueous suspension. It was possible to prepare microparticles by this method, but when the temperature increased above 24°C, the compound turned into a liquid, indicating that the microparticles were not heat stable. Example 9 A 1% chitosan acetate solution was prepared as described above. One gram of Octopirox® was dissolved in 8.5 g of molten Fischer-Tropsch wax (Sasolwax® H1, MP 112°C) and 4 g of damascone to form a clear solution at 120°C. Then, 62.5 g of the 1% chitosan solution and 20 g of water were measured. 1002616 of 39 The Octopirox® solution was heated to 120°C and added to the beaker under homogenization at 2000 rpm. The Octopirox® solution solidified immediately and failed to form fine particles of the compound. 1002616 of 39 MOELLER & CO. SA - 30529767664 Digitally signed by PORTALTRAM ITES - INPI Date: 2020.07.06 09:03:02 -03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 1002616

Claims

1. A composite particle for hair care, characterized in that it comprises: (i) an anti-dandruff agent; (ii) a wax or wax-like substance in which said anti-dandruff agent is soluble or dispersible, wherein the melting point of said wax and said substance is from 30°C to 105°C; and (iii) a cationic polymer having a weight-average molecular weight of 10³ Da to 10⁷ Da, wherein said composite particle has particles with a size of 0.1 to 1000 µm and wherein said wax-like substance is a C13 to C35 fatty alcohol; where said wax is at least one of beeswax, china wax, lanolin, shellac, spermaceti, myrica cerifera wax, candelilla wax, carnauba wax, castor wax, esparto grass wax, Japan wax, ouricury wax, rice bran wax, soybean wax, sebifera wax, ceresin wax, montana wax, ozocerite wax, and peat wax. Eleven claims follow.