CN115209859B - Cosmetic composition - 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

Cosmetic composition

Technical Field

The present invention relates to a composition useful in cosmetics, in particular in 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 in order to feel comfortable in daily life and work. Among them, many people are particularly concerned about the feeling of itching. Various factors may cause itching sensations, such as, for example, a highly dry body surface, the presence of certain bacteria on the body surface, allergies, external irritation or even psychological sensations, etc. Accordingly, in order to solve the itching sensation in humans, various products have been developed, many of which are used for relieving the itching sensation. In particular, considering various factors, soothing the itching sensation is generally more feasible and meaningful than a 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 the 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-in and/or rinse-off conditioners.

In addition to cleansing and conditioning functions, some other properties are also important to the consumer's appeal, e.g., 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 fatty phase in an aqueous phase, an emulsion (W/O) obtained by dispersing an aqueous phase in a fatty phase, or a multiple emulsion (W/O/W, O/W/O) are widely used in cosmetics. Thus, stability of the emulsion is of great concern, especially for products with 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 applications, 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 for 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 demand for versatility and appearance appeal.

Summary of The Invention

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

One subject of the present invention is therefore an oil-in-water (O/W) microemulsion composition useful for care products of 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 composition according to the invention is 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 solubilisers, preferably nonionic surfactants, may be beneficial for the compositions of the invention to obtain stable microemulsions, which may in turn be beneficial for cosmetics having a transparent appearance.

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

Embodiments of the invention

Throughout the specification, including the claims, unless the context requires otherwise, the term "comprise" and "comprises" are to be understood as synonymous with "comprising at least one". Furthermore, the expression "at least one" as used in this 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 …" and preferred embodiments defined by "consisting of …".

Except in the operating examples, or where otherwise indicated, all numbers expressing amounts 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 indicated number (e.g., "about 10%" means 9% -11%, and about "2%" means 1.8% -2.2%).

Throughout the specification, 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 materials are according to the invention locations where a feeling of itching is easily perceived, such as the scalp or skin, and/or locations where a feeling of itching affects, such as the hair.

Throughout the specification, including the claims, "care" and the like should be understood according to the present invention to include any means of maintaining, maintaining or improving the condition of keratin materials, including not only conventional means of care of 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 the present application, unless explicitly mentioned otherwise, the amounts, 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) fatty acid component comprising a plurality, e.g., at least 3, 4 or 5, medium chain fatty acids, and

(A-II) an ester component comprising a plurality, e.g., at least 3, 4, or 5, monoesters of 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 specification, including the claims, "microemulsion" according to the present invention refers to a thermodynamically stable isotropic liquid phase system containing at least three components of oily component, aqueous component and surfactant, wherein the dispersed phase has relatively small droplet size. In particular 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 droplet size is below 300nm, preferably below 200nm. Typically, the microemulsion may be centrifuged at a centrifugal force of up to 100G for at least 5 minutes without significant phase separation. Furthermore, the microemulsion is transparent with 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 haze, the better the clarity of the microemulsion.

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

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

The present invention thus provides the use of a fatty acid-ester mixture for soothing keratin materials on the body surface, in particular the itching feel of 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 invention comprises a fatty acid-ester mixture (a).

Fatty acid-ester mixture (A)

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

Useful fatty acids which can be used according to the invention as component (A-I) are medium-chain fatty acids, for example monocarboxylic acids preferably having from 6 to 20 carbon atoms, preferably from 8 to 16 carbon atoms, more preferably from 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-C₁₉, preferably C ₇-C₁₅, more preferably C ₇-C₁₁ hydrocarbon group, preferably alkyl; preferably, R is a linear group; more preferably, R is a linear 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 acid may be used alone or as a combination of two or more fatty acids. Preferably, the medium chain fatty acid is used as a combination of at least 3, 4 or 5 fatty acids.

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

According to one embodiment of the invention, the monoesters which can be used as component (A-II) are monoesters of the formula (II):

R-C(O)-OR’ (II)

Wherein:

r is as defined in 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 capric acid (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 C ₇-C₁₅ alkyl group and R' represents a residue from a linear polyol containing 2 to 6 carbon atoms.

According to one embodiment of the invention, the fatty acid according to formula (I) is preferably used in combination with the monoester according to formula (II) to form the 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 the monoester of formula (II) have the corresponding R groups. That is, if a fatty acid of formula (I) having an octyl group as R, i.e., octanoic acid, is used, a monoester of formula (II) having an octyl group as R, i.e., octanoic acid monoester, is used to form the fatty acid-ester mixture (a). Furthermore, if two or more fatty acids are used simultaneously for the mixture (a), two or more corresponding monoesters each having the same fatty acid moiety are used. 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 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 same polyols are preferably used to form monoesters corresponding to the fatty acid moieties. 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 particularly used, so that glycerides are formed with the various corresponding fatty acids mentioned above.

According to one embodiment of the present invention, for example, the fatty acid-ester mixture (a) contains 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 component (a-I). Meanwhile, the corresponding monoester of each fatty acid in component (A-I) is used as component (A-II). Preferably, the monoesters of components (A-II) are each glycerol esters.

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 component (a-II) contains caprylic acid glyceride (also referred to as monocaprylin), capric acid glyceride (also referred to as monocaprin), and lauric acid glyceride (also referred to as 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 of component (A-II), for example glycerides, are present in a ratio of 4:1 to 1:1, preferably 3:1 to 1:1, more preferably 2.5:1 to 1.5:1.

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

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

For example, when the fatty acid component (a-I) is esterified using glycerin, the usable fatty acid-ester mixture (a) may contain 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 components (a-I); glycerol monocaprylate, glycerol monocaprylate and glycerol monolaurate as components (a-II); and diglycerides and triglycerides of caprylic, capric and lauric acids.

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 wt%, preferably 80 wt% or less, or preferably 70 wt% or less, or preferably 65 wt% or less.

AVCO

According to one embodiment of the invention, for example, the fatty acid-ester mixture (a) may be of natural origin. Among them, it is well known that coconut oil contains a mixture of various C8-C20 fatty acids, especially those fatty acids having an even number of carbon atoms. Thus, it is desirable to use a derivative of coconut oil, for example, an esterification product of coconut oil, as the fatty acid-ester mixture (A) in the present invention.

Among the useful coconut oil derivatives are those known as Activated Virgin Coconut Oil (AVCO). Preferably, the coconut oil is esterified with glycerol. AVCO which can be used according to the invention can comprise octanoic acid, decanoic acid and lauric acid as components (A-I); glycerol monocaprylate, glycerol monocaprylate and glycerol monolaurate are used as components (A-II).

According to one embodiment of the invention, for example, as AVCO available, 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 4:1 to 1:1, preferably 3:1 to 1:1, more preferably 2.5:1 to 1.5:1. More specifically, for example, in exemplary embodiment 1 of AVCO, available 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 monoester component (A-II): glycerol monocaprylate in an amount of 0.5 to 15 wt%, preferably 1 to 10 wt% or preferably 4 to 7 wt%; glyceryl monocaprylate 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 the fatty acid component (A-I) and the monoester component (A-II).

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

When AVCO further contains a polyester selected from diglycerides and triglycerides, the content of the polyester is not particularly limited, for example, in an amount of 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.

According to one embodiment of the invention, for example, AVCO that may be used may comprise: a fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 5 to 40% by weight, preferably 10 to 30% by weight or preferably 20 to 25% by weight; 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%; from 10 to 50% by weight, preferably from 20 to 45% by weight or preferably from 30 to 40% by weight, of diglycerides of caprylic acid, capric acid and lauric acid; 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; each relative to the total amount AVCO.

Useful AVCO may preferably be AVCO prepared according to the teachings of EP 1973415, the disclosure of which is incorporated herein by reference. Accordingly, one 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 monocaprylate 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 monocaprylate and 75.54 mg/g glyceryl monolaurate; each relative to the total weight of AVCO; preferably 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 fatty acid-ester mixture (a) in an amount of 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 of 0.01 to 10 wt%, preferably 0.1 to 5 wt%, or preferably 0.3 to 1.5 wt%, 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 to form microemulsions.

The additional oil may be volatile or non-volatile.

The term "volatile oil" refers to any non-aqueous medium that can evaporate 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, which 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 "fixed oil" is intended to mean an oil that remains on the skin or keratin fibers at ambient temperature and atmospheric pressure.

More specifically, the evaporation rate of the fixed 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" refers to oils comprising at least one silicon atom, in particular at least one si—o group.

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

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

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

More preferably, the composition of the present invention comprises one or more hydrocarbon oils.

In particular, the volatile oils may be chosen from hydrocarbon oils having from 8 to 16 carbon atoms, and in particular branched C8-C16 alkanes (also known as isoparaffins or isoparaffins), such as isododecane (also known as 2,4, 6-pentamethylheptane), isodecane, isohexadecane, and oils sold for example under the trade name Isopars or PERMETHYLS.

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

The fixed oil may be chosen in particular from nonvolatile hydrocarbon oils.

As the nonvolatile hydrocarbon oil, there may be mentioned:

Hydrocarbon oils of animal origin, such as perhydro squalene,

Hydrocarbon oils of vegetable origin, such as, for example, vegetable stearyl esters, such as, for example, vegetable stearyl oleate, vegetable stearyl isostearate and lauroyl/octyldodecyl/vegetable stearyl glutamate (AJINOMOTO, ELDEW PS 203), diesters, such as, for example, diisopropyl sebacate, triglycerides composed of fatty acid esters of glycerol, in particular in which the fatty acids may have a chain length of from C4 to C36, and in particular from C18 to C36, these oils being linear or branched, and saturated or unsaturated; these oils may be in particular heptanoic or caprylic triglyceride, shea butter, alfalfa oil, poppy seed oil, pumpkin seed oil, millet oil, barley oil, quinoa oil, rye oil, candelilla oil, passion flower oil, aloe oil, sweet almond oil, peach seed oil, peanut oil, argan oil, avocado oil, babassu 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 seed oil, holjohn's oil, monoi oil, hazelnut oil, almond oil, nut oil, olive oil, evening primrose oil, palm oil, black currant seed oil, kiwi seed oil, grape seed oil, pistachio oil, pumpkin seed oil, quinoa oil, musk oil, sesame oil, soybean oil, sunflower oil, and castor oil, and mixtures thereof, or caprylic/capric triglyceride, such as those sold by STARINERIES DUBOIS company or those sold under the trade names Miglyol 810, 812 and 818 by the company Dynamit Nobel,

Linear or branched hydrocarbons of mineral or synthetic origin, for example liquid paraffins and derivatives thereof, vaseline, polydecene, polybutene, hydrogenated polyisobutene such as Parleam, squalane;

-an ether oil having 10 to 40 carbon atoms; for example, an ether oil of formula (III),

R ₃-O-R₄ (III)

In formula (III):

R ₃ and R ₄, which may be the same or different, represent a linear or branched C6-C25 alkyl or alkenyl group, R ₃ and R ₄ being selected such that the ether is liquid at a temperature of less than or equal to 25 ℃.

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

Preferably, the ether of formula (III) is selected from compounds in which the radicals R ₃ and R ₄, which may be identical or different, represent a linear or branched C6-C12 alkyl or alkenyl radical.

More particularly, according to the invention, the radicals R ₃ and R ₄ may be identical alkyl groups.

Among the ethers of formula (III), the preferred dialkyl ether is 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 represent C8 groups.

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.

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

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

According to one embodiment of the invention, the oil phase is present in an amount of 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 invention, the microemulsion composition comprises an aqueous phase as continuous phase. The aqueous phase is preferably present in an amount of 40 wt% to 99 wt%, more preferably 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 mixtures 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 and its preparation method

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

Organic solvents

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 straight-chain or branched and preferably saturated monohydric alcohols 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; polyhydric alcohol ethers such as ethylene glycol monomethyl, monoethyl and monobutyl ether, propylene glycol or ethers thereof such as propylene glycol monomethyl ether; and diethylene glycol alkyl ethers, especially C ₁-C₄ alkyl ethers, such as diethylene glycol monoethyl ether or monobutyl ether, alone or as mixtures.

When present, the organic solvent generally constitutes from 1% to 20% by weight, preferably from 2% to 15% by weight, or from 8% to 12% by weight, 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 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 solubilisers, in particular for oil-in-water microemulsions, the above-mentioned water-soluble organic solvents, for example alcohols, such as ethanol, propanol, etc., may be used as solubilisers, in particular for the complexes.

Among the nonionic surfactants which can be used according to the invention, mention may be made of, alone or as a mixture, fatty alcohols, alpha-diols and alkylphenols, these 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, alkylene oxides, such as ethylene oxide or propylene oxide, possibly in particular from 2 to 50, and/or glycerol groups possibly in particular from 2 to 30. Copolymers of ethylene oxide and propylene oxide, condensates of ethylene oxide and propylene oxide with fatty alcohols may also be mentioned; preference is given to polyethoxylated fatty amides having from 2 to 30 mol of ethylene oxide, polyglycerolated fatty amides containing an average of from 1 to 5, in particular from 1.5 to 4, glycerol groups, ethoxylated fatty acid sorbitan esters containing from 2 to 30 mol of ethylene oxide, fatty acid esters of sucrose, fatty acid esters of polyethylene glycol, alkylpolyglycosides, 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 alcohol;

Alkyl polyglycosides.

Wherein "fatty chain" refers to a straight or branched, saturated or unsaturated hydrocarbon-based chain containing from 6 to 30 carbon atoms, preferably from 8 to 30 carbon atoms.

These compounds are well known to those skilled in the art with respect to alkyl polyglycosides or APGs.

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 containing 8 to 24 carbon atoms, or an alkylphenyl group, wherein the linear or branched alkyl group contains 8 to 24 carbon atoms;

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

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

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

B refers to a value of 1 to 15.

Preferred alkylpolyglycosides useful in the compositions of the present invention are compounds of formula (XI) in which R ₁ more particularly represents a saturated or unsaturated, linear or branched alkyl group containing from 8 to 18 carbon atoms, a represents a value from 0 to 3, more particularly equal to 0, and G can 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 bond between the saccharide units is of the 1-6 or 1-4 type, preferably 1-4 type.

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

C ₈-C₁₆ alkyl 1, 4-polyglucosides, which are sold by Cognis under the name PLANTACARE ^® 818 UP as 53% aqueous solutions, can also be used.

With respect to mono-or polyglycerolated surfactants, they preferably comprise an average of from 1 to 30 glycerol groups, more particularly from 1 to 10 glycerol groups, particularly from 1.5 to 5.

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

R’’O[CH₂CH(CH₂OH)O]_mH,

R '' O [ CH ₂CH(OH)CH₂O]_m H or

R’’O[CH(CH₂OH)CH₂O]_mH；

In these formulae:

R '' represents a saturated or unsaturated, linear or branched hydrocarbon group containing 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 contain 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-C₂₀ alkyl and/or alkenyl group.

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

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

The (poly) ethoxylated fatty alcohols more particularly contain one or more linear or branched, saturated or unsaturated hydrocarbon groups containing 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 non-conjugated carbon-carbon double bonds.

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

Wherein the method comprises the steps of

-R ₃ represents a linear or branched C ₈-C₄₀ alkyl or alkenyl group, preferably a C ₈-C₃₀ alkyl or alkenyl group, optionally substituted with one or more hydroxy 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 from 8 to 22 carbon atoms, are oxyethylenated with from 1 to 30 moles of ethylene oxide (1 to 30 OE). Among these, lauryl alcohol 2 OE, lauryl alcohol 3 OE, decyl alcohol 3 OE, decyl alcohol 5 OE and oleyl alcohol 20 OE can be mentioned more particularly.

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

Among the nonionic surfactants, preference is given to using C ₆-C₂₄ -alkyl polyglucosides and (poly) ethoxylated fatty alcohols, more particularly C ₆-C₁₆ -alkyl polyglucosides.

According to the invention, the composition may comprise at least one fatty acid ester of glycerol and/or a fatty acid ester of polyglycerol to be used as a nonionic surfactant, which is different from the esters useful for the fatty acid-ester mixture (a) according to the invention, for example glycerol esters of C1 ₈-C₂₄ fatty acids and their oxyalkylenated derivatives.

According to a preferred embodiment, the one or more fatty acid esters of polyglycerols are selected from esters obtained from the reaction of polyglycerols comprising from 2 to 12 glycerol units, preferably from 3 to 10 glycerol units, with at least one fatty acid comprising from 8 to 24 carbon atoms, preferably from 8 to 22 carbon atoms, better still from 10 to 20 carbon atoms, better still from 10 to 18 carbon atoms. Fatty acids containing 8 to 24 carbon atoms may be linear or branched, 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 the group consisting of monoesters, diesters, triesters and tetraesters, polyesters and mixtures thereof. Preferably, esters with a low degree of esterification, such as fatty acid monoesters, diesters or triesters of polyglycerols, or mixtures are used. The fatty acid esters of polyglycerols may be in the form of a mixture of esters having a low degree of esterification, for example a mixture of mono-and di-esters or a mixture of mono-, di-and tri-esters.

According to one embodiment, the fatty acid ester of polyglycerol is selected from esters obtained 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 acid or linoleic acid.

In particular, polyglycerol-2 distearate, sold under the name Emalex PGSA by NIHON EMULSION; polyglycerol-10 decastearate, in particular sold under the name Sunsoft Q-1810S by TAIYO KAGAKU; glyceryl oleate, particularly sold under the name Monomuls 90-O18 by COGNIS; glyceryl stearate, in particular, is sold by cog is under the name cotina GMS V; polyglycerol-5 hexastearate, in particular sold under the name Sunsoft A-186E by TAIYO KAGAKU; polyglycerol-10 pentaoleate, in particular sold under the name Sunsoft Q-175S by TAIYO KAGAKU; polyglycerol-10 pentastearate, in particular 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, in particular sold under the name Sunsoft Q-17B by TAIYO KAGAKU; polyglycerol-5 trimyristate esters, in particular sold under the name Sunsoft A-143E by TAIYO KAGAKU; polyglycerol-2 octanoate, in particular sold under the name Sunsoft Q-81B by TAIYO KAGAKU; polyglycerol-2 laurate, in particular, is sold under the name Sunsoft Q-12D by TAIYO KAGAKU.

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

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

According to one embodiment, sorbitan esters of fatty acids (C ₈-C₂₄ fatty acid esters) and their oxyalkylenated derivatives may be used as nonionic surfactants. Oxidized alkylene fatty acid esters of sorbitan comprise, for example, 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 polyols and fatty acids having saturated or unsaturated chains containing, for example, 18 to 24 carbon atoms, and oxyalkylenated derivatives thereof, i.e. derivatives containing oxyethylenated and/or oxypropylated units, such as glycerides of C ₈-C₂₄ fatty acids, and oxyalkylenated derivatives thereof; polyethylene glycol esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; sorbitol esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; sorbitan esters of fatty acids (C ₈-C₂₄ fatty acid esters) and their oxyalkylenated derivatives; sugar (sucrose, glucose or alkyl glucose) esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; fatty alcohol ethers; sugar ethers of C ₈-C₂₄ fatty alcohols and mixtures thereof.

The at least one nonionic surfactant may be present in the compositions according to the invention in an amount of 15% to 80%, such as 20% to 70%, or 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 solubilizing agents is used to improve oil suspension in micelles and enhance transparency of shampoo products. 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 sulfate surfactant, the effective solubilizing agent complex can comprise 0.1-8% octyl/decyl glucoside and 0.1-3.5% alcohol, while in a clear shampoo without sulfate surfactant, the effective solubilizing agent complex can comprise 3-6% sorbitan polyoxyethylene (20) ether laurate and 2-4.5% alcohol, relative to the total weight of the composition.

Additional additives

According to various embodiments, the compositions of the present invention are for application to keratin materials, such as the skin, scalp or hair. According to these embodiments, the compositions of the present invention may comprise various ingredients conventionally used 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, anti-seborrheic agents, agents for preventing hair loss and/or promoting hair regrowth, vitamins and provitamins, including panthenol, sunscreens, chelating agents, plasticizers, acidulants, opacifiers, pearlizing agents (PEARLESCENT OR NACREOUS AGENTS), antioxidants, hydroxy acids, fragrances 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 in International Cosmetic Ingredient Dictionary and Handbook (9 th edition 2002).

The person skilled in the art will take care to choose the optional additional additives and/or the amounts thereof such that the addition considered does not or substantially not adversely affect the advantageous properties of the composition according to the invention.

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 particular product/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 the person skilled in the art. Nevertheless, it will be understood that the skilled person can choose the preparation method on the basis of his general knowledge, taking into account the nature of the ingredients used, for example 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 composition according to the invention is preferably useful for the production of shampoo products, scalp care products or even skin care products. From the detailed discussion above, it is to be understood that the shampoo, scalp care product, or even skin care product according to the present invention may advantageously have a transparent appearance. Also in light of the detailed discussion above, it is to be understood that the composition, and thus the shampoo product, according to the present invention may be free of silicone oil.

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 testing measurements. The following examples are intended to illustrate the invention and are not therefore limiting its scope.

Examples

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

Materials:

COCOS NUCIFERA (coconut) oil, activated Virgin Coconut Oil (AVCO), obtainable from BIOTROPICS

Other materials not described herein are each commercially available.

Example 1

Respectively preparing microemulsion I, II and comparative microemulsion I':

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
Tocopheryl acetate	0.02	0.02
			AVCO	20.7	0
Coco NUCIFERA oil/coco 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 microemulsion III:

Table 3:

INCI	microemulsion III
		Sorbitan polyoxyethylene (20) ether laurate	57.7
Ethanol	3
		Oleic acid glyceride	5.3
Tocopheryl 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 (microemulsion)	Turbidity (NTU)
		I	1.07
II	2.32
		I’	Opaque

Example 2

The microemulsion described above was used to formulate shampoo compositions A, B and D and comparative composition C, as in tables 4 and 5:

TABLE 5

INCI	Composition A	Comparative composition C
			Sodium lauryl polyoxyethylene 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 trimethyl ammonium chloride	0.3	0.3
			Citric acid	3	3
Ammonium hydroxide	1.2	1.2
			Sodium chloride	0.5	0.5
Hexanediol (Hexadiol)	0.5	0.5
			Spice	1.2	1.2
Water and its preparation method	QS to 100	QS to 100

TABLE 6

INCI	Composition B
		Sodium lauryl polyoxyethylene 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 (Hexadiol)	0.5
Spice	1.2
		Water and its preparation method	QS to 100

TABLE 7

INCI US	Composition D
		Lauroyl sarcosine sodium salt	6
Lauroyl methyl hydroxyethyl sodium sulfonate	3
		Cocoyl betaine	3.6
Microemulsion III	4.35
		Sorbitan polyoxyethylene (20) ether laurate	3
Polyoxyethylene (120) methyl glucose ether dioleate	2
		Salicylic acid	0.2
Sodium benzoate	0.5
		Hydroxypropyl guar hydroxypropyl trimethyl ammonium chloride	0.2
Ethanol	2
		Spice	0.7
Water and its preparation method	QS to 100

The above listed compositions a-D 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 feel of the composition a was evaluated for relief. Composition a was applied to the hair and scalp for 3 weeks per day in 5 volunteers aged 25 to 45 years, followed by 2 weeks without composition a. Antipruritic (soothing) sensation was evaluated for a total of 5 weeks. The score of the feeling of itching before application of composition a is given as a baseline, the score of the feeling of itching after application of composition a is given daily, and the average difference is shown in table 8.

The score is given and calculated as follows:

During the first 3 weeks, each volunteer was shampooed every night with composition a, using the conventional usage of each volunteer. In the next 2 weeks, each volunteer was also shampooed every night with standard shampoo containing no AVCO, wherein the conventional usage of each volunteer was still used.

Volunteers gave a score for the feeling of itching, wherein:

0 means unchanged;

-1 means a 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. Compositions a and D each were observed to exhibit very good and long-term antipruritic sensations even 2 weeks after the last application of the composition.

Claims (17)

1. An oil-in-water microemulsion composition for care and/or cleaning of keratin materials, comprising:

An oil phase comprising

(A) A fatty acid-ester mixture, which is an activated virgin coconut oil, comprising:

-fatty acid component (a-I):

octanoic acid in an amount of 5-20 wt%;

decanoic acid in an amount of 1-10 wt%; and

Lauric acid in an amount of 20-70 wt%;

And

Monoester component (a-II):

glycerol monocaprylate in an amount of 0.5 to 15 wt%;

Glyceryl monocaprylate in an amount of 0.1-10 wt%; and

Glycerol monolaurate in an amount of 10-40 wt%;

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

An aqueous phase comprising

(B) A solvent which is water and/or at least one alcohol, and

(C) At least one nonionic surfactant selected from the group consisting of glycerides of C ₁₈-C₂₄ fatty acids, and oxyalkylenated derivatives thereof; polyethylene glycol esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; sorbitol esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; sorbitan esters of C ₈-C₂₄ fatty acids and their oxyalkylenated derivatives; sugar esters of C ₈-C₂₄ fatty acids and oxyalkylenated derivatives thereof; fatty alcohol ethers; sugar ethers of C ₈-C₂₄ fatty alcohols and mixtures thereof,

Wherein the oil phase is present in an amount of 1 to 50 wt% relative to the total weight of the composition,

Wherein the nonionic surfactant (C) is present in the composition in an amount of 30% to 80% relative to the total weight of the composition,

Wherein the microemulsion composition is in the form of a transparent microemulsion.

2. The microemulsion composition according to claim 1, 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 4:1 to 1:1.

3. The microemulsion composition according to claim 1, 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 3:1 to 1:1.

4. The microemulsion composition according to claim 1, 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 2.5:1 to 1.5:1.

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

-fatty acid component (a-I):

Octanoic acid in an amount of 7-15 wt%;

decanoic acid in an amount of 2-8 wt%; and

Lauric acid in an amount of 30-60 wt%;

And

Monoester component (a-II):

Glycerol monocaprylate in an amount of 1-10 wt.%;

glyceryl monocaprylate in an amount of 1-8 wt%; and

Glycerol monolaurate in an amount of 15-35% by weight;

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

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

-fatty acid component (a-I):

octanoic acid in an amount of 8-10 wt%;

Decanoic acid in an amount of 4-7 wt%; and

Lauric acid in an amount of 40-55 wt%;

And

Monoester component (a-II):

glycerol monocaprylate in an amount of 4-7 wt%;

glyceryl monocaprylate in an amount of 3-5 wt%; and

Glycerol monolaurate in an amount of 20-30 wt%;

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

7. The microemulsion composition of claim 5, wherein the activated virgin coconut oil comprises:

-fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 5-40% by weight;

-monoester component (a-II) comprising glyceryl monocaprylate, glyceryl monocaprylate and glyceryl monolaurate in an amount of 1-30 wt%;

-10-50 wt.% of diglycerides of caprylic acid, capric acid and lauric acid in total; and

-Triglycerides of caprylic acid, capric acid and lauric acid in a total amount of 10-70% by weight;

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

8. The microemulsion composition of claim 5, wherein the activated virgin coconut oil comprises:

-fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 10-30% by weight;

-monoester component (a-II) comprising glyceryl monocaprylate, glyceryl monocaprylate and glyceryl monolaurate in an amount of 5-20 wt%;

-20-45% by weight of diglycerides of caprylic, capric and lauric acid in total; and

-Triglycerides of caprylic acid, capric acid and lauric acid in a total amount of 15-50% by weight;

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

9. The microemulsion composition of claim 5, wherein the activated virgin coconut oil comprises:

-fatty acid component (a-I) comprising caprylic acid, capric acid and lauric acid in an amount of 20-25% by weight;

-monoester component (a-II) comprising glyceryl monocaprylate, glyceryl monocaprylate and glyceryl monolaurate in an amount of 10-15 wt%;

-30-40% by weight of diglycerides of caprylic, capric and lauric acid in total; and

-Triglycerides of caprylic acid, capric acid and lauric acid in a total amount of 20-30% by weight;

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

10. The microemulsion composition according to claim 1 or 2, wherein the oil phase is present in an amount of 5 wt% to 30 wt% relative to the total weight of the composition.

11. The microemulsion composition according to claim 1 or 2, wherein the nonionic surfactant (C) is present in the composition in an amount of 40% to 70% relative to the total weight of the composition.

12. The microemulsion composition according to claim 1 or 2, wherein the solvent (B) is present in the composition in an amount of 10% to 50% relative to the total weight of the composition.

13. The microemulsion composition according to claim 1 or 2, wherein the solvent (B) is present in the composition in an amount of 20% to 40% relative to the total weight of the composition.

14. Microemulsion composition according to claim 1 or 2, comprising a complex of components (B) and (C) comprising 0.1 to 8% octyl/decyl glucoside and 0.1 to 3.5% alcohol, or a solubiliser complex comprising 3 to 6% sorbitan polyoxyethylene (20) ether laurate and 2 to 4.5% alcohol, relative to the total weight of the composition.

15. A shampoo product comprising a microemulsion composition according to any one of the preceding claims 1 to 14.

16. A scalp care product comprising a microemulsion composition according to any one of the preceding claims 1 to 14.

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