CN115209859A - Composition for cosmetics - Google Patents

Abstract

The present invention relates to an oil-in-water (O/W) microemulsion composition useful in products for the care of keratin materials, comprising an oil phase comprising (a) a fatty acid-ester mixture and an aqueous phase comprising (B) a solvent, such as water and/or at least one alcohol, and (C) at least one nonionic surfactant.

Description

Composition for cosmetics

Technical Field

The present invention relates to a composition useful in cosmetics, in particular products for caring for and/or cleansing keratin materials, in particular the scalp.

Background

Keratin materials are widely found on human surfaces, such as skin, scalp and hair. Many people have long sought to soothe the body surface so that they feel comfortable in daily life and work. Among these, many people are particularly concerned with the perception of itching. Various factors may cause itching, for example, high dryness of the body surface, presence of certain bacteria on the body surface, allergies, external stimuli or even psychological sensations, etc. Accordingly, in order to solve the human itching feeling, various products have been developed, many of which are used to relieve the itching feeling. In particular, taking into account various factors, relieving itching sensation is generally more feasible and meaningful than therapeutic treatment directed against these factors.

Among keratin materials on the body surface, the scalp is particularly susceptible to itching. Various formulations have been developed for itchy scalp, including those provided in separate forms, such as lotions, sprays, and the like, as well as those incorporated into conventional products for the hair and/or scalp, such as shampoos, leave-on and/or rinse-off conditioners.

In addition to cleansing and conditioning functions, several other properties are important to appeal to the consumer, for example, a special fragrance and good appearance. For example, some consumers prefer a transparent appearance.

Meanwhile, various emulsions, such as an emulsion (O/W) obtained by dispersing a fat phase in an aqueous phase, an emulsion (W/O) obtained by dispersing an aqueous phase in a fat phase, or a multiple emulsion (W/O/W, O/W/O), are widely used for cosmetics. Therefore, the stability of the emulsion is of great concern, especially for products having a desirable transparent appearance. It is well known that the stability of emulsions generally increases as the particle size of the emulsion decreases. Therefore, it is well known that microemulsions are widely used because they are thermodynamically stable.

On the other hand, for cosmetic use, natural ingredients, i.e. ingredients of natural origin, are of great interest to the consumer. Many compounds of natural origin are used for formulating care and/or make-up compositions of keratin materials. Efforts have been made to formulate compositions comprising natural ingredients.

Accordingly, there remains a need in the art to develop various intermediates, such as compositions, formulations, composites, and the like, to produce products that meet consumer needs for versatility and appearance appeal.

Summary of The Invention

In medical science, it has been disclosed that medium chain fatty acids and the respective corresponding monoglycerides have broad spectrum antimicrobial activity against enveloped viruses and various bacteria in vitro (Kabara, 1978, shibasaki and Kato, 1978, welsh et al 1979, thormar et al, 1987, isaacs et al 1995), including but not limited to human pathogens such as herpes simplex virus, candida albicans, chlamydia trachomatis, neisseria gonorrhoeae, helicobacter pylori and staphylococcus aureus. The inventors have now found that the use of fatty acid-ester mixtures of a plurality, for example at least 3, 4 or 5, of medium-chain fatty acids and of monoesters of the respective medium-chain fatty acids with lower polyols enables compositions to be obtained for caring for keratin materials, which can non-therapeutically relieve the itching sensation appearing on the keratin materials, in particular on the scalp.

A subject of the present invention is therefore an oil-in-water (O/W) microemulsion composition useful in care products for keratin materials, comprising:

an oil phase comprising a fatty acid-ester mixture of a plurality, e.g., at least 3, 4, or 5 medium chain fatty acids and a plurality, e.g., at least 3, 4, or 5 monoesters; and

an aqueous phase comprising water, at least one alcohol, and at least one nonionic surfactant.

The compositions according to the invention are particularly useful in keratin material care products such as shampoos, conditioners, scalp care conditioners, skin care products and the like.

According to one embodiment of the invention, the fatty acid-ester mixture is a derivative of coconut oil known as Activated Virgin Coconut Oil (AVCO).

The inventors have further surprisingly found that the use of specific solubilizers, preferably nonionic surfactants, can be beneficial for obtaining stable microemulsions of the compositions of the invention, which can in turn be beneficial for cosmetics having a transparent appearance.

It is noteworthy that, as introduced above, although medium-chain fatty acids and their monoglycerides are known to have antimicrobial activity, various factors can cause itching sensation. The compositions of the present invention have been found and have also been experimentally demonstrated to successfully alleviate the itching sensation. Without being bound by any known theory, it is believed that the soothing of itching using the compositions of the present invention successfully contributes at least in part to the sensory relaxation of the keratin materials by the compositions of the present invention. Thus, the compositions of the present invention are limited to non-therapeutic use, although further properties and/or mechanisms for therapeutic use may be discovered in the future.

Embodiments of the invention

Throughout the specification, including the claims, unless otherwise noted, the term "comprising a" should be understood as being synonymous with "comprising at least one". Further, the expression "at least one" used in the present specification is equivalent to the expression "one or more".

Throughout the specification, including the claims, embodiments defined by "comprising" and the like should be understood to encompass preferred embodiments defined by "consisting essentially of 8230composition" and preferred embodiments defined by "consisting of 8230composition".

Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients and/or reaction conditions are to be understood as being modified in all instances by the term "about", meaning within 10% of the number indicated (e.g., "about 10%" means 9% to 11%, and about "2%" means 1.8% to 2.2%).

Throughout the description, including the claims, a "keratin material" is according to the invention skin, hair, scalp, eyelashes, eyebrows, body hair, nails, lips or mucous membranes. Preferably, the keratin material is according to the invention easily perceived to be a itching feeling site, such as the scalp or skin, and/or affected by a itching feeling site, such as the hair.

Throughout the description, including the claims, "treating" and the like, are to be understood according to the invention as including any means of maintaining, maintaining or improving the condition of keratin materials, including not only conventional means of treating keratin materials such as the skin or scalp, but also any means known to be useful for conditioning and/or cleansing keratin materials such as the hair or scalp.

In this application, unless explicitly mentioned otherwise, contents, parts and percentages are by weight.

The present invention relates to an oil-in-water (O/W) microemulsion composition useful in care products for keratin materials, comprising:

an oil phase comprising

(A) A fatty acid-ester mixture comprising:

(A-I) a fatty acid component comprising a plurality, e.g. at least 3, 4 or 5, of medium chain fatty acids, and

(a-II) an ester component comprising a monoester of a plurality, e.g., at least 3, 4, or 5, medium chain fatty acids;

wherein medium chain fatty acids refer to monocarboxylic acids having 6 to 20 carbon atoms; and

an aqueous phase comprising

(B) A solvent, such as water and/or at least one alcohol, and;

(C) At least one nonionic surfactant.

Throughout the description, including the claims, a "microemulsion" according to the present invention refers to a thermodynamically stable isotropic liquid phase system containing at least three components, an oily component, an aqueous component and a surfactant, wherein the dispersed phase has a relatively small droplet size. Especially for O/W microemulsions, the droplet size of the dispersed oil is substantially below 300nm, i.e. more than 50%, preferably more than 80% of the droplets have a size below 300nm, preferably below 200nm. Typically, the microemulsion may be centrifuged at centrifugal forces up to 100G for at least 5 minutes without significant phase separation. Furthermore, the microemulsion is transparent and has a turbidity of less than or equal to 400 NTU, preferably less than or equal to 100 NTU, more preferably less than or equal to 10 NTU, more preferably less than or equal to 5 NTU, more preferably less than 3 NTU, even more preferably less than 2.5 NTU; assessed by HACH 2100AN turbidimeter (Loveland, USA). The lower the turbidity, the better the clarity of the microemulsion.

Preferably, the monoesters of the ester components (A-II) are obtained from esterification of medium chain fatty acids with lower polyols, respectively, used in component (A-I).

Preferably, the fatty acid-ester mixture is a derivative of coconut oil known as Activated Virgin Coconut Oil (AVCO).

The present invention therefore provides the use of a fatty acid-ester mixture for soothing itching sensations of keratin materials on the body surface, in particular the scalp.

Other features and advantages of the present invention will become more apparent upon reading the following specification and examples.

Oil phase

The oil phase comprises at least one oil. The term "oil" refers to any fatty substance that is in liquid form at room temperature (20-25 ℃) and atmospheric pressure. These oils may be of animal, vegetable, mineral or synthetic origin.

The oil phase of the microemulsion composition according to the present invention comprises the fatty acid-ester mixture (a).

Fatty acid-ester mixture (A)

The compositions of the invention comprise fatty acid-ester mixtures (a) of a plurality, for example at least 3, 4 or 5, of medium-chain fatty acids and of respective monoesters of medium-chain fatty acids with lower polyols.

Useful fatty acids which can be used as component (A-I) according to the invention are medium-chain fatty acids, for example monocarboxylic acids preferably having 6 to 20 carbon atoms, preferably 8 to 16 carbon atoms, more preferably 8 to 12 carbon atoms. Accordingly, useful fatty acids may have formula (I):

R-C(O)-OH (I)

wherein:

r represents a linear or branched, saturated or unsaturated C ₅ -C ₁₉ Preferably C ₇ -C ₁₅ More preferably C ₇ -C ₁₁ Hydrocarbyl, preferably alkyl; preferably, R is a linear group; more preferably, R is a straight chain alkyl group.

According to one embodiment of the invention, R preferably has an odd number, for example 5, 7, 9, 11, 13, 15, 17 or 19 carbon atoms. More preferably, R has 7, 9, 11, 13, or 15 carbon atoms; or preferably, R has 7, 9 or 11 carbon atoms.

According to one embodiment of the present invention, the medium-chain fatty acids may be used alone or as a combination of two or more fatty acids. Preferably, medium chain fatty acids are used as a combination of at least 3, 4 or 5 fatty acids.

The fatty acids useful according to the present invention may preferably be at least partially esterified with a polyol.

According to one embodiment of the invention, the monoester useful as component (A-II) is a monoester of formula (II):

R-C(O)-OR’ (II)

wherein:

r is as defined for formula (I).

R' represents a residue from a polyol. Useful polyols contain in particular from 2 to 20 carbon atoms, preferably from 2 to 10 carbon atoms, preferably from 2 to 6 carbon atoms, such as glycerol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol or diethylene glycol.

Preferably, the fatty acid according to formula (I) comprises caprylic acid (C8, also known as caprylic acid), capric acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C16), stearic acid (C18) or arachidic acid (C20).

More preferably, in formula (II), R and R' are different from each other, wherein R represents a linear chain C ₇ -C ₁₅ Alkyl, and R' represents a residue from a linear polyol containing 2 to 6 carbon atoms.

According to one embodiment of the invention, the fatty acids according to formula (I) are preferably used in combination with the monoesters according to formula (II) to form a fatty acid-ester mixture (a). Preferably, the fatty acids and monoesters used in mixture (a) relate to the same fatty acid moiety, i.e. the fatty acid of formula (I) and monoester of formula (II) have corresponding R groups. That is, if the fatty acid of formula (I) having octyl as R, i.e. caprylic acid, is used, the monoester of formula (II) having octyl as R, i.e. caprylic acid monoester, is used to form fatty acid-ester mixture (a). Furthermore, if two or more fatty acids are used simultaneously in mixture (a), the corresponding two or more monoesters are used, each having the same fatty acid moiety. In other words, according to one embodiment of the present invention, the fatty acid-ester mixture (a) may be regarded as a mixture of two or more fatty acids of formula (I) and a partially esterified monoester of each fatty acid.

According to one embodiment of the invention, the fatty acid-ester mixture (a) comprises a plurality, for example at least 3, 4 or 5, of fatty acids of formula (I) and monoesters of formula (II) having the same respective R groups as the fatty acids of formula (I), respectively. The monoester formation is preferably carried out using the same polyol, corresponding to the fatty acid moiety. That is, for two or more monoesters of formula (II) used in the fatty acid-ester mixture (a), they have the same R' group. Among these, glycerol is used in particular, so as to form glycerides with the various corresponding fatty acids mentioned above.

According to one embodiment of the present invention, for example, the fatty acid-ester mixture (a) comprises at least 3 fatty acids selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, to be used as the component (a-I). Meanwhile, the corresponding monoester of each fatty acid in the component (A-I) is used as the component (A-II). Preferably, the monoesters of the components (A-II) are each a glyceride.

Preferably, according to one embodiment of the present invention, the fatty acid component (a-I) comprises caprylic acid, capric acid and lauric acid. Meanwhile, the corresponding components (a-II) comprise glyceryl caprylate (also known as monocaprylin), glyceryl caprate (also known as monocaprrin), and glyceryl laurate (also known as glyceryl monolaurate (monolaurin)).

According to one embodiment of the invention, for example, with respect to the fatty acid-ester mixture (a), the total amount of fatty acids of component (a-I) and the total amount of monoesters, e.g., glycerides, of component (a-II) are present in a ratio of 4 to 1, preferably 3 to 1, more preferably 2.5.

According to one embodiment of the present invention, for example, the fatty acid-ester mixture (a) may be obtained by directly partially esterifying the fatty acid component (a-I) with a polyol to form a monoester, thereby obtaining a mixture of the fatty acid and the corresponding monoester as the ester component (a-II). When polyols are used, it is well known that polyesters, such as diesters, triesters, and the like, may eventually be formed. Accordingly, a fatty acid-ester mixture (a) comprising at least 3 fatty acids, monoesters corresponding to said at least 3 fatty acids and polyesters corresponding to said at least 3 medium-chain fatty acids can still be used in the present invention, provided that the main objective, in particular the antipruritic effect, is not significantly impaired.

For the purposes of the present invention, the term "polyester" refers to an ester formed by esterification of a polyol, wherein more than one hydroxyl group of the polyol molecule is esterified. Accordingly, "diester" and "triester" according to the present invention mean the esterification of two and three hydroxyl groups, respectively, of a polyol molecule.

For example, when the fatty acid components (a-I) are esterified using glycerol, useful fatty acid-ester mixtures (a) may comprise at least 3 fatty acids, monoesters, diesters, and triesters corresponding to the at least 3 fatty acids. For example, useful fatty acid-ester mixtures (a) may comprise caprylic acid, capric acid and lauric acid as component (a-I); glyceryl monocaprylate, glyceryl monocaprate and glyceryl monolaurate as components (A-II); and diglycerides and triglycerides of caprylic acid, capric acid and lauric acid.

When the fatty acid-ester mixture (a) further contains a polyester, the content of the polyester is not particularly limited as long as the main purpose of the mixture (a), particularly the antipruritic effect, is not significantly impaired. For example, polyesters may be used in mixture (a) in amounts up to 90% by weight, preferably 80% by weight or less, or preferably 70% by weight or less, or preferably 65% by weight or less.

AVCO

According to one embodiment of the invention, for example, the fatty acid-ester mixture (a) may be of natural origin. Of these, coconut oil is well known to contain mixtures of various C8-C20 fatty acids, especially those having an even number of carbon atoms. Accordingly, it is desirable that the present invention use a derivative of coconut oil, for example, an esterified product of coconut oil, as the fatty acid-ester mixture (a).

Among the coconut oil derivatives that may be used are those known as Activated Virgin Coconut Oil (AVCO). Preferably, the coconut oil is esterified with glycerin. The AVCO useful according to the present invention may comprise caprylic acid, capric acid and lauric acid as components (a-I); glyceryl monocaprylate, glyceryl monocaprate and glyceryl monolaurate as components (A-II).

According to one embodiment of the invention, for example, as available AVCO, the total amount of fatty acids of component (a-I) and the total amount of monoglycerides of component (a-II) are present in a ratio of 4 to 1, preferably 3 to 1, more preferably 2.5. More specifically, for example, in exemplary embodiment 1 of the AVCO, a useful AVCO may comprise: fatty acid component (a-I): octanoic acid in an amount of 5 to 20 wt.%, preferably 7 to 15 wt.% or preferably 8 to 10 wt.%; decanoic acid in an amount of 1 to 10 wt%, preferably 2 to 8 wt% or preferably 4 to 7 wt%; and lauric acid in an amount of 20 to 70 wt.%, preferably 30 to 60 wt.% or preferably 40 to 55 wt.%; and a monoester component (A-II): glyceryl monocaprylate in an amount from 0.5 to 15 wt%, preferably from 1 to 10 wt% or preferably from 4 to 7 wt%; glyceryl monocaprate in an amount of 0.1-10 wt%, preferably 1-8 wt% or preferably 3-5 wt%; and glycerol monolaurate in an amount of 10-40 wt.%, preferably 15-35 wt.% or preferably 20-30 wt.%; each relative to the total amount of fatty acid component (A-I) and monoester component (A-II).

The AVCO obtained from esterification of coconut oil may further comprise diglycerides and triglycerides in addition to the above fatty acid component (a-I) and monoester component (a-II). According to one embodiment of the present invention, for example, useful AVCO may comprise caprylic acid, capric acid and lauric acid as components (a-I); glyceryl monocaprylate, glyceryl monocaprate and glyceryl monolaurate as components (A-II); and optionally, diglycerides and triglycerides of caprylic acid, capric acid and lauric acid.

When the AVCO further comprises a polyester selected from the group consisting of diglycerides and triglycerides, the content of the polyester is not particularly limited, for example, an amount of at most 90 wt%, preferably 80 wt% or less, or preferably 70 wt% or less, or preferably 65 wt% or less.

According to one embodiment of the invention, for example, a useful AVCO may comprise: a fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 5-40 wt.%, preferably 10-30 wt.% or preferably 20-25 wt.%; a monoester component (a-II) comprising glycerol monocaprylate, glycerol monocaprate and glycerol monolaurate in an amount of 1-30 wt%, preferably 5-20 wt% or preferably 10-15 wt%; 10-50 wt.%, preferably 20-45 wt.% or preferably 30-40 wt.% of the total amount of caprylic acid, capric acid and lauric acid diglycerides; and 10 to 70 wt.%, preferably 15 to 50 wt.% or preferably 20 to 30 wt.% of triglycerides of caprylic acid, capric acid and lauric acid in total; each relative to the total amount of AVCO.

Useful AVCOs may preferably be AVCOs prepared according to the teachings of EP 1973415, the disclosure of which is incorporated herein by reference. Accordingly, an exemplary AVCO may comprise: 24.63 mg/g caprylic acid (C8), 17.81 mg/g capric acid (C10), 133.70 mg/g lauric acid (C12) and 11.82 mg/g glyceryl monocaprylate, 8.29 mg/g glyceryl monocaprate and 57.16 mg/g glyceryl monolaurate; or 23.10 mg/g caprylic acid (C8), 16.08 mg/g capric acid (C10), 116.81 mg/g lauric acid (C12) and 16.04 mg/g glyceryl monocaprylate, 10.35 mg/g glyceryl monocaprate and 75.54 mg/g glyceryl monolaurate; each relative to the total weight of the AVCO; preferably, the AVCO is derived from catalyzing coconut oil with a1, 3-specific lipase and subjecting it to glycerolysis.

According to one embodiment of the invention, the composition comprises the fatty acid-ester mixture (a) in an amount ranging from 0.1% to 40% by weight, preferably from 0.5% to 35% by weight, more preferably from 1% to 30% by weight, relative to the total weight of the microemulsion.

The fatty acid-ester mixture (a) may be present in the composition according to the invention in an amount ranging from 0.01% to 10% by weight, preferably from 0.1% to 5% by weight, or preferably from 0.3% to 1.5% by weight, relative to the total weight of the composition.

Additional oil

The oil phase may optionally comprise additional oils conventionally used for cosmetic use and/or for forming microemulsions.

The additional oil may be volatile or non-volatile.

The term "volatile oil" refers to any non-aqueous medium capable of evaporating from the skin or lips in less than one hour at room temperature (20-25 ℃) and atmospheric pressure (760 mmHg).

More specifically, the volatile oil may be a volatile cosmetic oil that is liquid at room temperature. More specifically, the volatile oil has an evaporation rate of 0.01-200 mg/cm ² Min, inclusive.

The term "non-volatile oil" is intended to mean an oil that remains on the skin or keratin fibres at ambient temperature and atmospheric pressure.

More specifically, the evaporation rate of the non-volatile oil is strictly less than 0.01 mg/cm ² /min。

Additional oils suitable for use in the present invention may be hydrocarbon-based, silicone-based, or fluorine-based. According to a preferred embodiment of the invention, the composition is free of silicone-based oils.

According to the invention, the term "silicone oil" means an oil comprising at least one silicon atom, in particular at least one Si — O group.

The term "fluoro oil" refers to an oil comprising at least one fluorine atom.

The term "hydrocarbon-based oil" refers to an oil comprising primarily hydrogen and carbon atoms.

The oil may optionally contain oxygen, nitrogen, sulfur and/or phosphorus atoms, for example, in the form of hydroxyl or acid groups.

More preferably, the compositions of the present invention comprise one or more hydrocarbon oils.

In particular, the volatile oil may be selected from hydrocarbon oils having from 8 to 16 carbon atoms, and in particular branched C8-C16 alkanes (also known as isoparaffins or isoalkanes), such as isododecane (also known as 2,4, 6-pentamethylheptane), isodecane, isohexadecane, and oils sold, for example, under the trade names Iso Gars or Permethyl @.

As hydrocarbon volatile oils, mention may also be made of the linear C9-C17 alkanes sold under the names PARAFOL 12-97 and PARAFOL 14-97 (Sasol), respectively, such as dodecane (C12) and tetradecane (C14), and the alkanes obtained according to the process described in the international application WO 2007/068371A1, such as the mixture of undecane (C11) and tridecane (C13) sold under the name CETIOL UT (Cognis).

The non-volatile oil may be chosen in particular from non-volatile hydrocarbon oils.

As the non-volatile hydrocarbon oil, there may be mentioned:

hydrocarbon oils of animal origin, such as perhydrosqualene,

hydrocarbon oils of vegetable origin, such as vegetable stearyl esters, such as vegetable stearyl oleate, vegetable stearyl isostearate and lauroyl/octyldodecyl/vegetable stearyl glutamate (AJINOMOTO, ELDEW PS 203), diesters, such as diisopropyl sebacate, triglycerides constituted by fatty acid esters of glycerol, in particular wherein the fatty acids may have a chain length of C4-C36, and in particular of C18-C36, these oils being linear or branched, and saturated or unsaturated; these oils may be in particular triglycerides of heptanoic acid or caprylic acid, shea butter, alfalfa oil, poppy seed oil, pumpkin seed oil, millet oil, barley oil, quinoa oil, rye oil, candlenut oil, passion flower oil, aloe vera oil, sweet almond oil, peach kernel oil, peanut oil, argan oil, avocado oil, baba oil, yerba mate oil, broccoli oil, calendula oil, camelina oil, canola oil, carrot oil, safflower oil, hemp oil, rapeseed oil, cottonseed oil, coconut oil, bone marrow seed oil, wheat germ oil, jojoba oil, lily oil, macadamia nut oil, corn oil, meadowfoam oil, john's wort oil, monoi oil, hazelnut oil, almond oil, nut oil, olive oil, evening primrose oil, palm oil, blackcurrant seed oil, pumpkin seed oil, grape seed oil, pistachio seed oil, watermelon seed oil, winter melon seed oil, quince oil, musk oil, sunflower oil, sesame oil, sunflower oil and mixtures thereof, or caprylic/capric triglyceride such as those sold by Starineries Dubois Inc. or those sold by Dynamit Nobel under the tradenames Miglyol 810, 812 and 818 ®,

linear or branched hydrocarbons of mineral or synthetic origin, such as liquid paraffins and derivatives thereof, petrolatum, polydecenes, polybutenes, hydrogenated polyisobutenes, such as Parleam, squalane;

-etheric oils having 10 to 40 carbon atoms; for example, ether oils of the formula (III),

R ₃ -O-R ₄ formula (III)

In formula (III):

R ₃ and R ₄ Which may be identical or different, represent a linear or branched C6-C25 alkyl or alkenyl radical, R being chosen from ₃ And R ₄ Such that the ether is liquid at a temperature less than or equal to 25 ℃.

According to the invention, the term "ether oil" means an oil that is liquid at room temperature (25 ℃), comprising at least one ether functional group.

Preferably, the ether of formula (III) is selected from the group R ₃ And R ₄ And may be the same or different, and represents a linear or branched C6-C12 alkyl or alkenyl compound.

More particularly, according to the invention, the radical R ₃ And R ₄ May be the same alkyl group.

Among the ethers of formula (III), preferred dialkyl ethers are selected from di-n-hexyl ether, di-n-heptyl ether, di-n-octyl ether, di-n-nonyl ether, di-n-decyl ether, diisodecyl ether, di-n-dodecyl ether, di-n-tetradecyl ether, di-n-hexadecyl ether, di-n-octadecyl ether or mixtures thereof.

R ₃ And R ₄ Preferably represents a C8 group.

The dialkyl ethers which may be used according to the invention may be soluble or insoluble in the composition, but are preferably insoluble.

These compounds can be prepared according to the process described in patent application DE 4127230.

Alternatively, di-n-octyl ether (INCI name: dioctyl ether) can be used in the context of the present invention. Such products are commercially available, for example those sold under the name Cetiol OE by Cognis (BASF) or Rofetan OE by Ecogleen Oleochogicals;

according to one embodiment of the present invention, the at least one additional oil may be present in an amount ranging from 0.01% to 40% by weight, preferably from 0.1% to 30% by weight, relative to the total weight of the microemulsion composition.

According to one embodiment of the invention, the oil phase is present in an amount ranging from 1% to 50% by weight, preferably from 5% to 30% by weight, relative to the total weight of the microemulsion composition.

Aqueous phase

According to the present invention, the microemulsion composition comprises an aqueous phase as the continuous phase. The aqueous phase is preferably present in an amount of from 40 wt% to 99 wt%, more preferably from 50 wt% to 85 wt%, based on the total weight of the composition.

The aqueous phase may comprise a solvent, such as water and at least one water-miscible organic solvent or a mixture thereof.

Solvent (B)

The composition according to the invention may advantageously comprise one or more solvents (B), such as water and/or organic solvents, in the aqueous phase.

Water (W)

The microemulsion composition according to the present invention comprises a content of water ranging from 0.5% to 40% by weight relative to the total weight of composition (I). The water content in the composition according to the invention is preferably from 5 to 40 wt.%, more preferably from 10 to 35 wt.%, or from 15 to 30 wt.%, relative to the total weight of the composition.

Organic solvent

The composition according to the invention may also comprise one or more organic solvents, preferably water-soluble organic solvents (water solubility greater than or equal to 5% at 25 ℃ and at atmospheric pressure).

Examples of organic solvents which may be mentioned include linear or branched and preferably saturated monoalcohols or diols containing from 2 to 10 carbon atoms, such as ethanol, isopropanol, hexanediol (2-methyl-2, 4-pentanediol), neopentyl glycol and 3-methyl-1, 5-pentanediol, butanediol, dipropylene glycol and propylene glycol; aromatic alcohols such as phenethyl alcohol; polyols containing more than two hydroxyl functions, such as glycerol; polyol ethers such as ethylene glycol monomethyl, monoethyl and monobutyl ethers, propylene glycol or ethers thereof, such as propylene glycol monomethyl ether; and diethylene glycol alkyl ethers, especially C ₁ -C ₄ Alkyl ethers, such as diethylene glycol monoethyl ether or monobutyl ether, alone or as a mixture.

When present, the organic solvent typically constitutes from 1 to 20 wt.%, preferably from 2 to 15 wt.%, or from 8 to 12 wt.%, relative to the total weight of the composition according to the invention.

The total solvent is typically present in the composition in an amount of from 10% to 50%, for example from 20% to 40%, relative to the total weight of the composition, including all ranges and subranges therebetween.

Solubilizer/nonionic surfactant (C)

The fatty acid-ester mixture (a), in particular AVCO, is incorporated in the oil phase of the oil-in-water (O/W) microemulsion according to the present invention. Accordingly, the solubilizer is preferably contained in the aqueous phase. For good suspension of the oil phase, the solubilizer is preferably a nonionic surfactant or a mixture thereof, more preferably a complex of solubilizers. As solubilizers, in particular for oil-in-water microemulsions, water-soluble organic solvents mentioned above, for example alcohols, such as ethanol, propanol, etc., can be used as solubilizers, in particular for the complexes.

Among the nonionic surfactants which can be used according to the invention, mention may be made, alone or as a mixture, of fatty alcohols, α -diols and alkylphenols, the three types of compounds being oxyalkylated, such as polyethoxylated and/or polypropoxylated and/or polyglycerolated, and containing fatty chains comprising, for example, from 6 to 40 carbon atoms, the number of alkylene oxides, such as ethylene oxide or propylene oxide groups, possibly being in particular from 2 to 50, and/or the number of glycerol groups possibly being in particular from 2 to 30. Mention may also be made of copolymers of ethylene oxide and propylene oxide, condensates of ethylene oxide and propylene oxide with fatty alcohols; polyethoxylated fatty amides having preferably from 2 to 30 mol of ethylene oxide, polyglycerolated fatty amides having an average of from 1 to 5, in particular from 1.5 to 4, glycerol groups, sorbitan esters of ethoxylated fatty acids having from 2 to 30 mol of ethylene oxide, fatty acid esters of sucrose, fatty acid esters of polyethylene glycol, alkyl polyglycosides, N-alkylglucamine derivatives, amine oxides, such as (C10-C14) alkylamine oxides or N-acylaminopropyl morpholine oxides.

The nonionic surfactant is preferably selected from:

(poly) ethoxylated fatty alcohols;

glycerinated fatty alcohols;

alkyl polyglycosides.

Wherein "aliphatic chain" means a linear or branched, saturated or unsaturated hydrocarbyl chain containing from 6 to 30 carbon atoms, preferably from 8 to 30 carbon atoms.

With regard to the alkyl polyglycosides or APGs, these compounds are well known to the person skilled in the art.

These compounds are more particularly represented by the following general formula:

in formula (XI):

R ₁ represents a saturated or unsaturated, linear and branched alkyl and/or alkenyl group comprising from 8 to 24 carbon atoms, or an alkylphenyl group, wherein the linear or branched alkyl group thereof comprises from 8 to 24 carbon atoms;

R ₂ represents an alkylene group containing about 2 to 4 carbon atoms;

g represents a sugar unit comprising 5 to 6 carbon atoms;

a denotes a value of 0 to 10, preferably 0 to 4, and

b means a value of 1 to 15.

Preferred alkyl polyglycosides useful in the compositions of the invention are those wherein R is ₁ More particularly a saturated or unsaturated, linear or branched alkyl radical comprising from 8 to 18 carbon atoms, a represents a value from 0 to 3, more particularly equal to 0, and G may represent glucose, fructose or galactose, preferably glucose.

The degree of polymerization, i.e. the value of b in formula (I), may be from 1 to 15, preferably from 1 to 4. The average degree of polymerization is more particularly 1 to 2, still more preferably 1.1 to 1.5.

The glycosidic linkages between the saccharide units are of the 1-6 or 1-4 type, preferably 1-4 type.

Representative of the compounds of formula (I) are especially Cognis in Plantaren ^® (600 CS/U, 1200 and 2000) or Plantacare ^® (818, 1200, and 2000) are products sold under the name. Seppic can also be used as Triton CG 110 (or Oramix CG 110) and Triton CG 312 (or Oramix CG 312) ^® NS 10) is sold under the name octyl/decyl glucoside, BASF is sold under the name Lutensol GD 70, or Chem Y is sold under the name AG10 LK.

It is also possible to use, for example, cognis in Plantacare ^® 818 UP is sold under the name C as a 53% aqueous solution ₈ -C ₁₆ Alkyl 1, 4-polyglucosides.

As regards mono-or polyglycerolated surfactants, they preferably comprise on average from 1 to 30 glycerol groups, more particularly from 1 to 10 glycerol groups, in particular from 1.5 to 5.

The mono-or polyglycerolated surfactant is preferably selected from compounds of the formula:

R’’O[CH ₂ CH(CH ₂ OH)O] _m H,

R’’O[CH ₂ CH(OH)CH ₂ O] _m h or

R’’O[CH(CH ₂ OH)CH ₂ O] _m H；

In these formulae:

r '' represents a saturated or unsaturated, linear or branched hydrocarbon radical comprising from 8 to 40 carbon atoms, preferably from 10 to 30 carbon atoms; m is an integer from 1 to 30, preferably from 1 to 10, more particularly from 1.5 to 6; r "may optionally comprise heteroatoms, such as oxygen and nitrogen. In particular, R "may optionally comprise one or more hydroxyl and/or ether and/or amide groups. R' preferably represents a mono-or polyhydroxylated C ₁₀ -C ₂₀ Alkyl and/or alkenyl.

Chimex and Chimexane, for example, can be used ^® NF is the polyglycerolated (3.5 mol) hydroxy lauryl ether sold under the name NF.

The (poly) ethoxylated fatty alcohols suitable for carrying out the present invention are more particularly chosen from alcohols containing from 8 to 30 carbon atoms, preferably from 12 to 22 carbon atoms.

The (poly) ethoxylated fatty alcohol more particularly contains one or more linear or branched, saturated or unsaturated hydrocarbon groups comprising from 8 to 30 carbon atoms, which are optionally substituted, in particular by one or more (in particular from 1 to 4) hydroxyl groups. If they are unsaturated, these compounds may contain from 1 to 3 conjugated or unconjugated carbon-carbon double bonds.

The one or more (poly) ethoxylated fatty alcohols preferably have the following formula (XII):

wherein

- R ₃ Represents a straight or branched chain C ₈ -C ₄₀ Alkyl or alkenyl, preferably C ₈ -C ₃₀ Alkyl or alkenyl, optionally substituted with one or more hydroxyl groups, and

c is an integer from 1 to 200 (including 1 and 200), preferably from 2 to 50, more particularly from 8 to 30, such as 20.

The (poly) ethoxylated fatty alcohols, more particularly fatty alcohols containing 8 to 22 carbon atoms, are oxyethylenated with 1 to 30 moles of ethylene oxide (1 to 30 OE). Among these, mention may be made more particularly of lauryl alcohol 2 OE, lauryl alcohol 3 OE, decanol 5 OE and oleyl alcohol 20 OE.

Mixtures of these (poly) oxyethylenated fatty alcohols may also be used.

Among the nonionic surfactants, C is preferably used ₆ -C ₂₄ Alkyl polyglucosides and (poly) ethoxylated fatty alcohols, more particularly using C ₆ -C ₁₆ An alkyl polyglucoside.

According to the invention, the composition may comprise at least one fatty acid ester of glycerol and/or of polyglycerol for use as a nonionic surfactant, which is different from the esters, e.g. C1, that can be used in the fatty acid-ester mixture (a) according to the invention ₈ -C ₂₄ Glycerides of fatty acids and oxygen thereforAn alkylated derivative.

According to a preferred embodiment, the one or more fatty acid esters of polyglycerol are chosen from esters resulting from the reaction of a polyglycerol comprising 2 to 12 glycerol units, preferably 3 to 10 glycerol units, and at least one fatty acid containing 8 to 24 carbon atoms, preferably 8 to 22 carbon atoms, better 10 to 20 carbon atoms, better 10 to 18 carbon atoms. The fatty acids containing from 8 to 24 carbon atoms may be straight or branched chain, and saturated or unsaturated.

The fatty acid may be selected from oleic acid, stearic acid, isostearic acid, lauric acid, palmitic acid, myristic acid, linoleic acid, capric acid and caprylic acid, or mixtures thereof.

The fatty acid esters of polyglycerol may be selected from mono-, di-, tri-and tetra-esters, polyesters and mixtures thereof. It is preferred to use esters with a low degree of esterification, such as fatty acid mono-, di-or triesters of polyglycerol, or mixtures. The fatty acid ester of polyglycerol may be in the form of a mixture of esters having a low degree of esterification, for example a mixture of mono-and diesters or a mixture of mono-, di-and triesters.

According to one embodiment, the fatty acid ester of polyglycerol is selected from esters resulting from the reaction of polyglycerol comprising 3 to 10 glycerol units and at least one fatty acid containing 8 to 20 carbon atoms, preferably 10 to 18 carbon atoms, such as oleic or linoleic acid.

Mention may in particular be made of polyglycerol-2 distearate, in particular sold under the name Emalex PGSA by NIHON EMULSION; polyglycerol-10 decastearate, particularly sold under the name Sunsoft Q-1810S by TAIYO KAGAKU; glyceryl oleate, particularly sold by COGNIS under the name Monomuls 90-O18; glyceryl stearate, in particular sold by COGNIS under the name Cutina GMS V; polyglycerol-5 hexastearate, particularly sold under the name Sunsoft a-186E by TAIYO KAGAKU; polyglycerol-10 pentaoleate, particularly sold by TAIYO KAGAKU under the name Sunsoft Q-175S; polyglycerol-10 pentastearate, particularly sold under the name Sunsoft Q-185S by TAIYO KAGAKU; polyglycerol-4 isostearate, in particular sold under the name Isolan GI 34 by EVONIK GOLDSCHMIDT; diisostearoyl polyglycerol-3 dimer dilinoleate, particularly sold under the name Isolan PDI by EVONIK GOLDSCHMIDT; polyglycerol-2 oleate sold especially by TAIYO KAGAKU under the name Sunsoft Q-17B; polyglycerol-5 trimyristate, in particular sold under the name Sunsoft a-143E by TAIYO KAGAKU; polyglyceryl-2 caprylate, sold especially under the name Sunsoft Q-81B by TAIYO KAGAKU; polyglycerol-2 laurate, particularly sold under the name Sunsoft Q-12D by TAIYO KAGAKU.

According to a particular embodiment, the fatty acid suitable for reaction with one or more esters of polyglycerol comprises at least one hydroxyl group. This is the case for ricinoleic acid. Mention may in particular be made of polyglycerol-3 ricinoleate (and) sorbitan isostearate, in particular sold under the name Arlacel 1690 by CRODA, and polyglycerol-3 ricinoleate, in particular sold under the name Akoline PGPR by aarhuskarl shamn.

According to another embodiment, the fatty acid suitable for reaction with the one or more esters of polyglycerol is a polyacid comprising at least one hydroxyl group.

According to one embodiment, the sorbitan ester of a fatty acid (C) ₈ -C ₂₄ Fatty acid esters) and oxyalkylenated derivatives thereof are useful as nonionic surfactants. The oxyalkylenated fatty acid esters of sorbitan comprise, for example, from 20 to 100 EO, such as those sold under the trade names Tween 20, tween 60 or Tween 80.

Examples of useful nonionic surfactants may thus comprise esters of polyhydric alcohols and fatty acids having a saturated or unsaturated chain containing, for example, from 18 to 24 carbon atoms, and oxyalkylenated derivatives thereof, i.e. derivatives containing oxyethylenated and/or oxypropylenated units, such as C ₈ -C ₂₄ Glycerol esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Polyethylene glycol esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Sorbitol esters of fatty acids, and oxyalkylenated derivatives thereof; sorbitan esters of fatty acids (C) ₈ -C ₂₄ Fatty acid esters), and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Sugar (sucrose, glucose or alkyl glucose) esters of fatty acids, and their oxyalkylenated derivatives;a fatty alcohol ether; c ₈ -C ₂₄ Sugar ethers of fatty alcohols and mixtures thereof.

The at least one nonionic surfactant may be present in the compositions according to the present invention in an amount ranging from 15% to 80%, such as from 20% to 70%, or from 25% to 50%, relative to the total weight of the composition, including all ranges and subranges therebetween.

According to one embodiment of the invention, the complex of solubilizers is used to improve the oil suspension in the micelles and to enhance the transparency of the shampoo product. Complexes of at least one of the above nonionic surfactants with the above alcohols useful as organic solvents are preferred. For example, in a clear shampoo containing a sulfate surfactant, an effective solubilizing agent complex can comprise 0.1-8% octyl/decyl glucoside and 0.1-3.5% alcohol, relative to the total weight of the composition, while in a clear shampoo without a sulfate surfactant, an effective solubilizing agent complex can comprise 3-6% sorbitan polyoxyethylene (20) ether laurate and 2-4.5% alcohol.

Additive

According to various embodiments, the composition of the invention is intended to be applied to keratin materials, such as the skin, the scalp or the hair. According to these embodiments, the compositions of the invention may comprise various ingredients conventionally usable in care and/or cleansing compositions for keratin materials, such as additional surfactants, including anionic and amphoteric surfactants, active ingredients, moisturizers, additional fatty substances, antidandruff agents, antiseborrheic agents, agents to prevent hair loss and/or to promote hair regrowth, vitamins and provitamins, including panthenol, sunscreens, chelating agents, plasticizers, acidulants, opacifying agents, pearlizing agents (pearling agents), antioxidants, hydroxy acids, perfumes, and preservatives.

A non-exhaustive list of these ingredients can be found in U.S. patent application publication 2004/0170586, the entire contents of which are incorporated herein by reference. Further examples of such additional ingredients can be found inInternational Cosmetic Ingredient Dictionary and Handbook(9 th edition 2002).

The person skilled in the art will take care to select the optional additional additives and/or the amounts thereof such that the advantageous properties of the composition according to the invention are not or substantially not adversely affected by the addition in question.

These additives can be variously selected by those skilled in the art to prepare compositions having desired properties, such as consistency or texture. In particular, the additives (if used) and their amounts are determined in particular according to the specific product/its application, for example lotions, leave-on conditioners, shampoos, creams, rinse-off conditioners and the like.

These additives may be present in the composition in an amount of 0.01% to 50% relative to the total weight of the composition, including all ranges and subranges therebetween.

Method and use

The compositions according to the invention can generally be prepared according to the general knowledge of a person skilled in the art. Nevertheless, it will be understood that the person skilled in the art may select a preparation method on the basis of his general knowledge, taking into account the properties of the ingredients used, such as their solubility in the carrier and the application envisaged for the composition or kit.

According to one embodiment, the composition according to the invention can be used for preparing products for caring for and/or cleansing keratin materials, in particular the hair, the skin and the scalp.

The compositions according to the invention can preferably be used for the production of shampoo products, scalp care products or even skin care products. From the above detailed discussion, it is to be understood that shampoo products, scalp care products, or even skin care products according to the present invention can advantageously have a transparent appearance. Also in light of the above detailed discussion, it is to be understood that the compositions according to the present invention, and thus shampoo products, may be free of silicone oils.

The invention is further illustrated by the following examples, which illustrate particularly advantageous embodiments.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective measurements. The following examples are intended to illustrate the invention without thereby limiting its scope.

Examples

The amounts/concentrations of the ingredients in the compositions/formulations described below are expressed in weight percent relative to the total weight of each composition/formulation.

Materials:

COCOS NUCIFERA (COCONUT) OIL Activated Virgin COCONUT (AVCO), available from BIOTROPICS

Other materials not described herein are each commercially available.

Example 1

Microemulsions I, II and comparative microemulsion I' were prepared separately:

table 1:

INCI	microemulsion I	Microemulsion I'
			Octyl/decyl glucoside	34.6	34.6
Ethanol	10.9	10.9
			Oleic acid glyceride	5.3	5.3
Tocopherol acetate	0.02	0.02
			AVCO	20.7	0
Cocos NUCIFERA (coconut) oil/Cocos NUCIFERA oil	0	20.7
			Water/AQUA	QS to 100	QS to 100

Table 2:

INCI	microemulsion II
		Tween 80	39.2
Dipropylene glycol	9.8
		AVCO	27.5
Water/AQUA	QS to 100

Preparing a microemulsion III:

table 3:

INCI	microemulsion III
		Sorbitan polyoxyethylene (20) ether laurate	57.7
Ethanol	3
		Oleic acid glyceride	5.3
Tocopherol acetate	0.02
		AVCO	20.7
Menthol	4.6
		Water/AQUA	QS to 100

Microemulsions I to III are transparent, whereas comparative microemulsion I' is opaque, i.e. no microemulsion is formed.

Table 4:

microemulsion	Turbidity (NTU)
		I	1.07
II	2.32
		I’	Is not transparent

Example 2

The above microemulsions were used to formulate shampoo compositions a, B and D and comparative composition C, as shown in tables 4 and 5:

TABLE 5

INCI	Composition A	Comparative composition C
			Sodium lauryl Ether sulfate	13	13
Cocoamidopropyl betaine	2.4	2.4
			Microemulsion I	4.35	0
Microemulsion I'	0	4.35
			Salicylic acid	0.2	0.2
Sodium benzoate	0.5	0.5
			Ethanol	3.5	3.5
Propylene glycol	0.8	0.8
			Polyquaternium-10	0.3	0.3
Hydroxypropyl guar hydroxypropyl trimonium chloride	0.3	0.3
			Citric acid	3	3
Ammonium hydroxide	1.2	1.2
			Sodium chloride	0.5	0.5
Hexanediol	0.5	0.5
			Perfume	1.2	1.2
Water (I)	QS to 100	QS to 100

TABLE 6

INCI	Composition B
		Sodium lauryl Ether sulfate	13
Cocoamidopropyl betaine	2.5
		Microemulsion II	3.27
Salicylic acid	0.2
		Sodium benzoate	0.5
Ethanol	2
		Propylene glycol	0.8
Polyquaternium-10	0.3
		Hydroxypropyl guar hydroxypropyl trimethyl ammonium chloride	0.3
Citric acid	3
		Ammonium hydroxide	1.2
Sodium chloride	0.5
		Hexanediol	0.5
Perfume	1.2
		Water (W)	QS to 100

TABLE 7

INCI US	Composition D
		Sodium lauroyl sarcosinate	6
Sodium lauroyl methyl isethionate	3
		Cocoamylbetaine	3.6
Microemulsion III	4.35
		Sorbitan polyoxyethylene (20) ether laurate	3
Polyoxyethylene (120) methylgluc ether dioleate	2
		Salicylic acid	0.2
Sodium benzoate	0.5
		Hydroxypropyl guar hydroxypropyl trimethyl ammonium chloride	0.2
Ethanol	2
		Perfume	0.7
Water (W)	QS to 100

The compositions A-D listed above were prepared according to manufacturing methods known in the art.

Compositions a-D were obtained with shampoo products according to the invention. In particular, compositions A, B and D are transparent and composition C is opaque.

Example 3

The soothing feel of composition a was evaluated. 5 volunteers 25 to 45 years old applied composition a daily for 3 weeks on hair and scalp, followed by 2 weeks without composition a. Itching (soothing) was assessed over a total of 5 weeks. The score of itching sensation before application of composition a was given as baseline and the score of itching sensation after application of composition a was given daily, with the average difference shown in table 8.

The scores are given and calculated as follows:

in the first 3 weeks, each volunteer was shampooed every night with composition a, using the usual usage of each volunteer. In the next 2 weeks, each volunteer was also shampooed every night with a standard shampoo without AVCO, with the normal usage of each volunteer still being used.

Volunteers gave scores for itching sensation, where:

0 means unchanged;

-1 means moderate improvement;

-2 means a significant improvement; and

-3 means substantially no itching sensation.

The average score of 5 volunteers was counted daily and the weekly average was calculated. The average score for a total of 5 weeks is provided in table 8 below.

TABLE 8

	Week 1	Week 2	Week 3	Week 4	Week 5
						Composition A	-0.5	-1.0	-1.7	-1.3	-1.1
Composition D	-0.7	-0.9	-1.5	-1.3	-1.1

Referring to table 8, the lower the score, the less itching sensation. It was observed that each of compositions a and D exhibited a very good and long-lasting scratchiness even 2 weeks after the last application of the composition.

Claims (14)

1. An oil-in-water microemulsion composition useful in products for caring for and/or cleaning keratin materials, comprising:

an oil phase comprising

(A) A fatty acid-ester mixture comprising:

(A-I) a fatty acid component comprising a plurality, e.g. at least 3, 4 or 5, of medium chain fatty acids, and

(a-II) an ester component comprising a monoester of a plurality, e.g., at least 3, 4, or 5, medium chain fatty acids;

wherein the medium chain fatty acid refers to a monocarboxylic acid having 6 to 20 carbon atoms; and

an aqueous phase comprising

(B) A solvent, such as water and/or at least one alcohol, and

(C) At least one nonionic surfactant.

2. The microemulsion composition according to claim 1, wherein the fatty acid-ester mixture (a) comprises at least 3 fatty acids selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, for use as component (a-I); and the corresponding glycerides of the respective fatty acids in component (A-I) are used as component (A-II);

preferably, the fatty acid component (a-I) comprises caprylic acid, capric acid and lauric acid; and the corresponding components (A-II) comprise glycerol monocaprylate, glycerol monocaprate and glycerol monolaurate; and

wherein the total amount of fatty acids of component (a-I) and the total amount of monoesters of component (a-II) are present in a ratio of 4.

3. The microemulsion composition according to claim 1 or 2, wherein the fatty acid-ester mixture (a) is activated virgin coconut oil comprising:

-fatty acid component (a-I):

octanoic acid in an amount of 5 to 20 wt.%, preferably 7 to 15 wt.% or preferably 8 to 10 wt.%;

capric acid in an amount of 1-10 wt%, preferably 2-8 wt% or preferably 4-7 wt%; and

lauric acid in an amount of 20-70 wt.%, preferably 30-60 wt.% or preferably 40-55 wt.%;

and

monoester components (a-II):

glyceryl monocaprylate in an amount of 0.5-15 wt%, preferably 1-10 wt% or preferably 4-7 wt%;

glyceryl monocaprate in an amount of 0.1 to 10 wt.%, preferably 1 to 8 wt.% or preferably 3 to 5 wt.%; and

glycerol monolaurate in an amount of 10-40 wt.%, preferably 15-35 wt.% or preferably 20-30 wt.%;

each relative to the total amount of fatty acid component (A-I) and monoester component (A-II).

4. The microemulsion composition of claim 3, wherein the activated virgin coconut oil comprises:

-a fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 5-40 wt.%, preferably 10-30 wt.% or preferably 20-25 wt.%;

-a monoester component (a-II) comprising glyceryl monocaprylate, glyceryl monocaprate and glyceryl monolaurate in an amount of 1-30 wt%, preferably 5-20 wt% or preferably 10-15 wt%;

-10-50 wt.%, preferably 20-45 wt.% or preferably 30-40 wt.% of the total amount of caprylic acid, capric acid and lauric acid diglycerides; and

-triglycerides of caprylic acid, capric acid and lauric acid in a total amount of 10-70 wt.%, preferably 15-50 wt.% or preferably 20-30 wt.%;

each relative to the total amount of activated virgin coconut oil.

5. The microemulsion composition according to any of the preceding claims, wherein the oil phase is present in an amount of from 1 wt% to 50 wt%, preferably from 5 wt% to 30 wt%, relative to the total weight of the composition.

6. According to the frontThe microemulsion composition of any of the preceding claims, wherein the at least one nonionic surfactant (C) is selected from C ₁₈ -C ₂₄ Glycerol esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Polyethylene glycol esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Sorbitol esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Sorbitan esters of fatty acids, and oxyalkylenated derivatives thereof; c ₈ -C ₂₄ Sugar esters of fatty acids, and oxyalkylenated derivatives thereof; a fatty alcohol ether; c ₈ -C ₂₄ Sugar ethers of fatty alcohols and mixtures thereof.

7. The microemulsion composition according to any of the preceding claims, wherein the non-ionic surfactant (C) is present in the composition in an amount ranging from 30% to 80%, such as from 40% to 70% relative to the total weight of the composition, including all ranges and subranges therebetween.

8. The microemulsion composition according to any of the preceding claims, wherein the solvent (B) is selected from water and at least one water-miscible organic solvent.

9. The microemulsion composition according to any of the preceding claims, wherein the solvent (B) is present in the composition in an amount of from 10% to 50%, such as from 20% to 40%, relative to the total weight of the composition, including all ranges and subranges therebetween.

10. The microemulsion composition according to any of the preceding claims, comprising a complex of components (B) and (C) containing from 0.1 to 8% of octyl/decyl glucoside and from 0.1 to 3.5% of alcohol, relative to the total weight of the composition, or a complex of solubilizers containing from 3 to 6% of sorbitan polyoxyethylene (20) ether laurate and from 2 to 4.5% of alcohol.

11. The microemulsion composition according to any of the preceding claims, in the form of a transparent microemulsion.

12. A shampoo product comprising the microemulsion composition according to any one of the preceding claims 1-11.

13. A scalp care product comprising a microemulsion composition according to any one of the preceding claims 1-11.

14. A skin care product comprising the microemulsion composition according to any one of the preceding claims 1-11.