WO2024122393A1

WO2024122393A1 - Composition for improved straightening of keratin fibers

Info

Publication number: WO2024122393A1
Application number: PCT/JP2023/042435
Authority: WO
Inventors: Tomotaka Michitsuji
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2022-12-09
Filing date: 2023-11-21
Publication date: 2024-06-13
Anticipated expiration: 2025-06-09

Abstract

The present invention relates to a composition for straightening keratin fibers, such as hair, with heating, comprising: (a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof; (b) at least one organic acid metal salt; and (c) water. The present invention can improve a composition for straightening keratin fibers such as hair based on heating the keratin fibers with glyoxylic acid or a derivative thereof, by providing the keratin fibers with less color fading effects and/or longer-lasting straightening effects.

Description

DESCRIPTION

TITLE OF INVENTION

COMPOSITION FOR IMPROVED STRAIGHTENING OF KERATIN FIBERS

TECHNICAL FIELD

The present invention relates to a composition, in particular a cosmetic composition, for straightening keratin fibers such as hair,

BACKGROUND ART

Straightening keratin fibers such as hair by heating the keratin fibers with an iron is popular for making unruly keratin fibers manageable and making keratin fibers have less volume and look more desirable. Such a straightening method using a heating iron is convenient for quick styling, but the style lasts only short period of time, e.g., until the next shampooing. A long-lasting straightening method is required for many consumers.

On the other hand, conventional permanent straightening methods using a reducing agent and an alkaline agent, as well as an oxidizing agent, with heating, can provide keratin fibers with a long-lasting style, but they have several drawbacks such as a long processing time, damage to the keratin fibers and malodor.

WO 2014/131469 discloses a composition for straightening keratin fibers by heating with an iron, without using reducing and oxidizing agents, wherein the composition includes glyoxylic acid.

DISCLOSURE OF INVENTION

There is still a need to improve the straightening of keratin fibers based on heating the keratin fibers with glyoxylic acid or a derivative thereof.

An objective of the present invention is to provide an improved composition for straightening keratin fibers such as hair, based on heating the keratin fibers with glyoxylic acid or a derivative thereof, which can prevent or reduce color fading of the keratin fibers and/or can provide the keratin fibers with longer-lasting straightening effects.

The above objective of the present invention can be achieved by a composition for straightening keratin fibers, such as hair, with heating, comprising:

(a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof;

(b) at least one organic acid metal salt; and

(c) water.

The pH of the composition according to the present invention may be 7 or less, preferably 6 or less, and more preferably 5 or less.

The amount of the (a) compound(s) in the composition according to the present invention may be from 0.1% to 50% by weight, preferably from 0.5% to 40% by weight, and more preferably from 1% to 30% by weight, relative to the total weight of the composition.

The metal of the (b) organic acid metal salt may be selected from magnesium, calcium, and zinc.

The organic acid of the (b) organic acid metal salt may be selected from a-hydroxy acids, preferably selected from the group consisting of glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, and gluconic acid.

The (b) organic acid metal salt may be magnesium, calcium or zinc gluconate.

The amount of the (b) organic acid metal salt(s) in the composition according to the present invention may be from 0.1% to 15% by weight, preferably from 0.2% to 10% by weight, and more preferably from 0.3% to 5% by weight, relative to the total weight of the composition.

The amount of the (c) water in the composition according to the present invention may be from 20% to 99% by weight, preferably from 30% to 95% by weight, and more preferably from 40% to 90% by weight, relative to the total weight of the composition.

The composition according to the present invention may further comprise (d) at least one betaine compound, preferably selected from the group consisting of trimethylglycine, carnitine, and L-proline betaine or stachydrine, and mixtures thereof.

The amount of the (d) betaine compound(s) in the composition according to the present invention may be from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight, relative to the total weight of the composition.

The composition according to the present invention may not comprise any ammonia or a thiol compound, or may comprise less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of ammonia or a thiol compound, relative to the total weight of the composition.

The composition according to the present invention may not comprise any reducing agent or oxidizing agent, or may comprise less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of a reducing agent or an oxidizing agent, relative to the total weight of the composition.

The present invention also relates to a process for straightening keratin fibers, such as hair, comprising the steps of:

(i) applying a composition onto the keratin fibers;

(ii) optionally rinsing off the keratin fibers, with or without drying the keratin fibers after being rinsed off; and

(iii) straightening the keratin fibers at a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C, wherein the composition comprises:

(b) at least one organic acid metal salt; and

(c) water.

The present invention also relates to a kit for straightening keratin fibers such as hair, comprising: at least one heater, preferably a heating iron, which is capable of providing the keratin fibers with a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C; and at least one composition comprising

(b) at least one organic acid metal salt; and

(c) water.

The present invention also relates to a use of (b) at least one organic acid metal salt in a composition for straightening keratin fibers such as hair, with heating, comprising:

(a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof; and

(c) water, in order to prevent or reduce color fading of the keratin fibers and/or lengthen the straightening effects for the keratin fibers by the composition, in particular in order to further maintain the straight shape of the keratin fibers, or prevent or reduce waving of the keratin fibers.

BEST MODE FOR CARRYING OUT THE INVENTION

After diligent research, the inventors have found that it is possible to provide an improved composition for straightening keratin fibers such as hair, based on heating the keratin fibers with glyoxylic acid or a derivative thereof, which can prevent or reduce color fading of the keratin fibers and/or can provide longer-lasting straightening effects.

Thus, the present invention mainly relates to a composition, preferably a cosmetic composition, for straightening keratin fibers such as hair, with heating, comprising:

(b) at least one organic acid metal salt; and

(c) water.

The present invention can improve a composition for straightening keratin fibers such as hair, based on heating the keratin fibers with glyoxylic acid or a derivative thereof, by providing the keratin fibers with less color fading effects and/or longer-lasting straightening effects.

The present invention can prevent or reduce the color fading of keratin fibers. Thus, the color of keratin fibers before and after being treated with the present invention can be maintained or does not substantially change. For example, the color of dyed keratin fibers would not substantially change before and after being treated with the present invention.

The present invention can provide keratin fibers such as hair with longer-lasting straightening effects. Thus, the present invention can lengthen or prolong the straightening effects for keratin fibers provided by using a composition including only glyoxylic acid or a derivative thereof. In particular, the present invention can further maintain the straight shape of keratin fibers, or can prevent or reduce loss of the straight shape of keratin fibers over time.

For example, if keratin fibers are originally wavy, the present invention can provide better prevention for the keratin fibers returning to the original wavy shape, after straightening the keratin fibers, in particular after shampooing.

In the present invention, the use of at least one organic acid metal salt can prevent or reduce color change of keratin fibers by straightening and/or can lengthen or prolong the straightening effects for the keratin fibers provided by glyoxylic acid or a derivative thereof. In particular, the use of at least one organic acid metal salt can prevent or reduce color fading of dyed keratin fibers and/or can further maintain the straight shape of the keratin fibers provided by glyoxylic acid or a derivative thereof, or can prevent or reduce waving of the keratin fibers.

The present invention can also provide keratin fibers with sufficient immediate straightening effects. Thus, the keratin fibers treated with the present invention can have less volume or less frizz due to the reduction of curls of the keratin fibers. The straightening effects provided by the present invention can last a long time, for example, even after shampooing the keratin fibers. Thus, the present invention can also provide the shape of keratin fibers with good resistance to shampooing.

The present invention can provide keratin fibers with less damage as compared to conventional straightening processes, because the present invention does not need to use any reducing/oxidizing agents. Therefore, it can be easy to comb the keratin fibers treated by the present invention. Thus, the keratin fibers treated with the present invention can be easy to manage. Also, the keratin fibers treated by the present invention can be stronger than those treated by conventional straightening processes.

In addition, the present invention can use no or very little ammonia or a thiol compound, and therefore, odor during the use of the present invention can be reduced as compared to the conventional processes which require the use of ammonia or a thiol compound. Also, the present invention can have good usability, for example, short processing time.

Hereafter, the present invention will be described in a detailed manner.

[Composition]

The composition according to the present invention, for straightening keratin fibers such as hair, with heating, comprises:

(b) at least one organic acid metal salt; and (c) water.

It is preferable that the above composition be a cosmetic composition, more preferably a cosmetic composition for straightening keratin fibers, and even more preferably a cosmetic composition for one-step straightening keratin fibers. It is particularly preferable that the keratin fibers be hair.

(Glyoxylic Acid and Derivatives Thereof)

The composition according to the present invention includes (a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof.

A single type of (a) compound may be used, but two or more different types of (a) compounds may be used in combination.

The (a) compound is selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof. In other words, the (a) compound is selected from glyoxylic acid and derivatives thereof.

As glyoxylic acid solvates, mention may be made of, for example, glyoxylic acid hydrates such as glyoxylic acid monohydrate.

As glyoxylic acid salts, mention may be made of, for example, alkaline metal salts or alkaline earth metal salts of glyoxylic acid such as sodium or potassium glyoxylate, and magnesium or calcium glyoxylate.

As glyoxylic acid esters, mention may be made of, for example, alkyl esters of glyoxylic acid such as methyl glyoxylate and ethyl glyoxylate.

As glyoxylic acid amides, mention may be made of, for example, N-glyoxyloylcarbocysteine and N- glyoxyloyl keratin amino acids.

It is preferable to use glyoxylic acid as the (a) compound.

The amount of the (a) compound(s) in the composition according to the present invention may be 0.1% by weight or more, preferably 0.5% by weight or more, and more preferably 1% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the (a) compound(s) in the composition according to the present invention may be 50% by weight or less, preferably 40% by weight or less, and more preferably 30% by weight or less, relative to the total weight of the composition.

[Organic Acid Metal Salt] The composition according to the present invention includes (b) at least one organic acid metal salt. Two or more such salts may be used in combination. Thus, a single type of such a salt or a combination of different types of such salts may be used.

If a plurality of organic acid metal salts are used, it is possible that the types of organic acid are different and/or the types of metal are different.

The metal of the (b) organic acid metal salt may be selected from alkaline metals, in particular sodium and potassium.

The metal of the (b) organic acid metal salt may be selected from alkaline earth metals, in particular magnesium and calcium.

The metal of the (b) organic acid metal salt may be selected from transition metals and the group 12 elements in the periodic table such as zinc.

The organic acid of the (b) organic acid metal salt may be selected from a-hydroxy acids.

The a-hydroxy acids may be represented by the following formula (I):

wherein

R1=H, -OH, -NH2, -CH2COOH or a linear or branched C1-4 alkyl,

R2=H,- COOH, -CHOH-COOH, -CF₃,- CH=CH₂, -NHCONH2, a linear, branched or cyclic C_1-8 alkyl optionally substituted with a radical chosen from -OH, Cl, -NHz, -COOH, -CF3 and -SCH3; a phenyl or benzyl optionally substituted with one -OH or -OCH3 radical; or alternatively the radical

, and

R1 and R2 may also together form an oxo radical (=0) or a cyclopropyl, cyclobutyl, hydroxycyclobutyl, cyclopentyl or cyclohexyl ring with the carbon atom that bears them, or alternatively the radical

when R1=H, R2 may also represent a -(CHOH)₂CH₂OH or -(CHOH)₃CH₂OH radical, R = - OH or -NR3R4 with R3, R4 = H or a linear or branched C1-4 alkyl optionally substituted with one or two OH radicals, as well as stereoisomers, organic or mineral salts and solvates thereof.

The a-hydroxy acids may be selected from the following: glycolic acid, oxalic acid, lactic acid, 1 -hydroxy- 1 -cyclopropanecarboxylic acid, 2-hydroxy-3- butenoic acid, 2-hydroxyisobutyric acid, 2-hydroxy-n-butyric acid, isoserine, glyceric acid, 2- hydroxy- 3 -methylbutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxyvaleric acid, 4- amino-2-hydroxybutyric acid, 1 -hydroxycyclohexanecarboxylic acid, dihydroxyfumaric acid, citramalic acid, tartaric acid, citric acid, 2-hydroxy-4-(methylthio)butyric acid, mandelic acid, 2 -hydroxy-3 -methylvaleric acid, glyoxylurea, [3-imidazolelactic acid, 2 -trifluoromethyl -2- hydroxypropionic acid, hexahydromandelic acid, 2-hydroxyoctanoic acid, arabic acid, 3- phenylactic acid, hydroxyphenylglycine, 3 -hydroxymandelic acid, 4-hydroxymandelic acid,

2-hydroxynonanoic acid, L-arginic acid, 3 -methoxymandelic acid, 4-methoxymandelic acid,

3-(4-hydroxyphenyl)lactic acid, tartronic acid, (3-chlorolactic acid, 1 -cyclopentanol- 1- carboxylic acid, 1 ,2-dihydroxycyclobutanecarboxylic acid, 2-ethyl-2-hydroxybutric acid, a- hydroxyisocaproic acid, a-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, malic acid, hydroxytartronic acid, gluconic acid, lactamide, N-methyllactamide, N-ethyllactamide, N,N-dimethyllactamide, N-2-hydroxyethyllactamide, and stereoisomers, organic or mineral salts and solvates thereof,

It may be preferable that the a-hydroxy acid be selected from the group consisting of glycolic acid, oxalic acid, L-lactic acid, DL-lactic acid, D-lactic acid, malic acid, tartaric acid, DL- glyceric acid, arabic acid, gluconic acid, hydroxytartronic acid, lactamide, N- methyllactamide, N-ethyllactamide, and N-2 -hydroxy ethyllactamide.

It may be more preferable that a-hydroxy acid be selected from the group consisting of gluconic acid, glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, and mandelic acid.

It may be even more preferable that the (b) organic acid metal salt be magnesium gluconate, calcium gluconate or zinc gluconate.

The amount of the (b) organic acid metal salt(s) in the composition according to the present invention is 0.1% by weight or more, preferably 0.2% by weight or more, and more preferably 0.3% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the (b) organic acid metal salt(s) in the composition according to the present invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

The amount of the (b) organic acid metal salt(s) in the composition according to the present invention may be from 0.1% to 15% by weight, preferably from 0.2% to 10% by weight, and more preferably from more than 0.3% to 5% by weight, relative to the total weight of the composition.

(Water)

The composition according to the present invention includes (c) water.

Thus, the composition according to the present invention is not anhydrous.

The amount of the (c) water in the composition according to the present invention is 20% by weight or more, preferably 30% by weight or more, and more preferably 40% by weight or more relative to the total weight of the composition. On the other hand, the amount of the (c) water in the composition according to the present invention may be 99% by weight or less, preferably 95% by weight or less, and more preferably 90% by weight or less relative to the total weight of the composition.

The amount of (c) water in the composition according to the present invention may be from 20% to 99% by weight, preferably from 30% to 95% by weight, and more preferably from 40% to 90% by weight relative to the total weight of the composition.

(Betaine Compound)

The composition according to the present invention may further include (d) at least one betaine compound. A single type of specific betaine compound may be used, or two or more different types of betaine compounds may be used in combination.

The term “betaine compound” here means an amphoteric compound having a positively charged cationic moiety and a negatively charged anionic moiety, wherein no hydrogen atom is bound to a positively charged atom in the positively charged cationic moiety and the positively charged cationic moiety may not be adjacent to the negatively charged anionic moiety.

For the purpose of the present invention, the (d) betaine compound here is not a surfactant, which comprises at least one hydrophilic part and at least one hydrophobic part.

The positively charged cationic moiety in the (d) betaine compound includes, but is not limited to, a quaternary ammonium cation, a phosphonium cation, and a sulfonium cation. Preferably, the (d) betaine compound includes a quaternary ammonium cation as the positively charged cationic moiety.

The negatively charged anionic moiety in the (d) betaine compound includes, but is not limited to, a carboxylate anion.

The (d) betaine compound may be selected from the group consisting of trimethylglycine, carnitine, L-proline betaine or stachydrine, and mixtures thereof and preferably be trimethylglycine.

The amount of the (d) betaine compound(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1 % by weight or more relative to the total weight of the composition. It may be even more preferable that the amount of the (d) betaine compound(s) in the composition according to the present invention be 0.2% by weight or more relative to the total weight of the composition.

On the other hand, the amount of the (d) betaine compound(s) in the composition according to the present invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less relative to the total weight of the composition, It may be even more preferable that the amount of the (d) betaine compound(s) in the composition according to the present invention be 3% by weight or less relative to the total weight of the composition. The amount of the (d) betaine compound(s) in the composition according to the present invention may range from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight relative to the total weight of the composition. It may be even more preferable that the amount of the (d) betaine compound(s) in the composition according to the present invention be from 0.2% to 3% by weight relative to the total weight of the composition.

(pH)

The composition according to the present invention may have a pH of 7 or less, preferably 6 or less, and more preferably 5 or less, which is measured at 25°C.

The composition according to the present invention may have a pH of 3 or more, which is measured at 25°C.

The composition according to the present invention may have a pH of from 3 to 7, preferably from 3 to 6, and more preferably from 3 to 5, which is measured at 25°C.

(Alkaline Agent)

The composition for straightening keratin fibers, according to the present invention, may include at least one alkaline agent. Two or more alkaline agents may be used in combination. Thus, a single type of alkaline agent or a combination of different types of alkaline agents may be used.

The alkaline agent is different from the (d) betaine compound.

It is preferable that the composition according to the present invention include alkaline agent(s), if the (a) compound can function to reduce the pH of the composition.

The alkaline agent may be an inorganic alkaline agent. It is preferable that the alkaline agent be non-volatile. It is preferable that the inorganic alkaline agent be selected from the group consisting of alkaline metal hydroxides; alkaline earth metal hydroxides; and alkaline metal phosphates and monohydrogen phosphates such as sodium phosphate or sodium monohydrogen phosphate.

As examples of the inorganic alkaline metal hydroxides, mention may be made of sodium hydroxide, lithium hydroxide and potassium hydroxide. As examples of the alkaline earth metal hydroxides, mention may be made of calcium hydroxide and magnesium hydroxide. As the inorganic alkaline agent, sodium hydroxide and potassium hydroxide are preferable.

The alkaline agent may be an organic alkaline agent. It is preferable that the organic alkaline agent be selected from the group consisting of monoamines and diamines.

As examples of the monoamines, mention may be made of alkanolamines such as mono-, di- and tri-ethanolamine, comprising 1 to 3 hydroxyalkyl(Ci-C4) groups. Particularly, alkanolamines may be selected from monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, N,N-dimethyl ethanolamine, 2-amino-2-methyl- 1 -propanol, triisopropanolamine, 2-amino-2-methy 1-1, 3 -propanediol, 3 -amino- 1,2- propanediol, 3-dimethylamino-l,2-propanediol, and tris(hydroxymethylamino)methane. The diamines may be described in the structure (B) below:

wherein W denotes an alkylene such as propylene optionally substituted by a hydroxyl or a C₁-C₄ alkyl radical, and R_a, Rb, R_c and Rd independently denote a hydrogen atom, an alkyl radical or a C₁-C₄ hydroxyalkyl radical, which may be exemplified by 1,3 -propanediamine and derivatives thereof.

The amount of the alkaline agent(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0,05% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the alkaline agent(s) in the composition according to the present invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

The alkaline agent(s) may be used in a total amount of from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight, relative to the total weight of the composition.

(Acid)

The composition for straightening keratin fibers, according to the present invention, may include at least one acid which is different from the (a) compound or (d) betaine compound. Two or more acids may be used in combination, Thus, a single type of acid or a combination of different types of acids may be used.

The acid may be used to adjust the pH of the composition according to the present invention.

It is preferable that the composition according to the present invention include acid(s), if the (a) compound can function to increase the pH of the composition.

As the acid, mention may be made of any inorganic or organic acids which are commonly used in cosmetic products such as citric acid, lactic acid, sulfuric acid, phosphoric acid or hydrochloric acid (HC1). HC1 is preferable.

The amount of the acid(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the acid(s) in the composition according to the present invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

The acid(s) may be used in a total amount of from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight, relative to the total weight of the composition.

(Other Optional Ingredients)

The composition according to the present invention may also comprise at least one other optional ingredient, chosen in particular from: oils, preferably polar oils, and more preferably ester oils, in the form of a liquid at 25°C under atmospheric pressure; solid fatty substances and in particular C₈-C₄₀ esters, C₈-C₄₀ acids, and C₈-C₄₀ alcohols, at 25°C under atmospheric pressure; thickeners; sunscreens; moisturizers; antidandruff agents; antioxidants; chelating agents; nacreous agents and opacifiers; plasticizers or coalescers; fillers; emulsifiers; polymers, in particular conditioning polymers, such as cationic polymers; fragrances; silanes; crosslinking agents; surfactants including anionic, cationic, amphoteric and nonionic surfactants . The composition can, of course, comprise several cosmetic ingredients appearing in the above list.

The composition according to the present invention may include one or several cosmetically acceptable organic solvents, which may be alcohols: in particular monovalent alcohols such as ethyl alcohol, isopropyl alcohol, benzyl alcohol, and phenylethyl alcohol; diols such as ethylene glycol, propylene glycol and caprylyl glycol; other polyols such as glycerol; and ethers such as ethylene glycol monomethyl, monoethyl, and monobutyl ethers, propylene glycol monomethyl, monoethyl, and monobutyl ethers, and butylene glycol monomethyl, monoethyl, and monobutyl ethers.

Depending on their nature and the purpose of the composition, the above optional ingredient(s) can be present in normal amounts which can be easily determined by those skilled in the art and which can be, for each ingredient, between 0.01% and 80% by weight. Those skilled in the art will take care to choose the ingredients included in the composition, and also the amounts thereof, such that they do not harm the properties of the compositions used for the present invention.

(Ammonia and Thiol Compound)

It is preferable that the composition according to the present invention be free of ammonia or a thiol compound. The term “free of ammonia or a thiol compound” means that the composition according to the present invention does not include a substantial amount of ammonia or a thiol compound. Preferably the composition according to the present invention includes 1% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.1% by weight or less of ammonia or a thiol compound, in particular no ammonia or thiol compound.

Due to the very small amount or the absence of ammonia and/or thiol compound, malodor during the use of the composition according to the present invention can be reduced or prevented.

The thiol compound here means a compound which has at least one thiol (-SH) group.

The thiol compound may be a reducing agent. The thiol reducing agent may be chosen from the group consisting of thioglycolic acid and derivatives thereof, in particular esters thereof such as glycerol or glycol monothioglycolate; thiolactic acid and derivatives thereof, in particular esters thereof such as glycerol monothiolactate; 3 -mercaptopropionic acid and derivatives thereof, in particular esters thereof such as glycerol 3 -mercaptopropionate and ethyleneglycol 3 -mercaptopropionate; cysteamine and derivatives thereof, in particular C₁-C₄ acyl derivatives thereof such as N-acetylcysteamine and N-propionylcysteamine; monothioglycerol and derivatives thereof, in particular esters; cysteine and derivatives thereof, in particular esters such as N-acetylcysteine, N-alkanoylcysteine and cysteine alkyl esters; thioglycerine and derivatives thereof, in particular s-alkyl derivatives, and salts thereof.

As the above salts, mention may be made of, for example, ammonium salts; primary-, secondary- or tertiary-amine salts; alkaline metal salts; and, alkaline earth metal salts. As the primary-, secondary- or tertiary-amine, for example, monoethanolamine, diisopropanolamine or triethanolamine, respectively, may be mentioned.

Other examples of the thiol reducing agent include, but are not limited to, sugar N-mercapto alkyl amides such as N-(mercapto-2-ethyl)gluconamide, P-mercaptopropionic acid and derivatives thereof; thiomalic acid; pantheteine; N-(mercaptoalkyl)co-hydroxyalkyl amides such as those described in European Patent Application No. 0 354 835 and N-mono- or N,N- dialkylmercapto 4-butyramides such as those described in European Patent Application No. 0 368 763; aminomercaptoalkyl amides such as those described in European Patent Application No. 0 432 000 and alkylaminomercaptoalkylamides such as those described in European Patent Application No. 0 514 282; (2/3) hydroxy-2 propyl thioglycolate; and the hydroxy-2 methyl- 1 ethyl thioglycolate-based mixture (67/33) described in French Patent Application No. 2 679 448.

(Reducing Agent and Oxidizing Agent)

The composition according to the present invention may comprise a reducing agent; however, it is preferable that the composition according to the present invention comprises a reduced amount of a reducing agent or an oxidizing agent, preferably free of a reducing agent or an oxidizing agent.

The term “free of a reducing agent or an oxidizing agent” means that the composition according to the present invention does not include a substantial amount of a reducing agent or an oxidizing agent. Preferably the composition according to the present invention includes 1% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.1% by weight or less of a reducing agent or an oxidizing agent, in particular no reducing agent or no oxidizing agent.

The reducing agent may be a thiol reducing agent or a non-thiol reducing agent. The thiol reducing agent is as described above.

The non-thiol reducing agent here means a reducing agent with no thiol group. The non- thiol reducing agent may be chosen from the group consisting of sulfites, bisulfites, sulfinates, phosphines, sugars, reductones and hydrides. The non-thiol reducing agent may be selected from ammonium sulfites and bisulfites as well as metal sulfites and bisulfites, more preferably alkali metal or alkali earth metal sulfites and bisulfites, and more preferably sodium sulfites and bisulfites.

The oxidizing agent may be chosen from hydrogen peroxide, alkali metal bromates, ferricyanides peroxygenated salts, and compounds capable of producing hydrogen peroxide by hydrolysis. For example, the oxidizing agent can be chosen from aqueous hydrogen peroxide solution, urea peroxide, alkali metal bromates and persalts such as perborates and persulphates

(Form)

The compositions according to the present invention may be in any form suitable for topical application, and in particular in the form of an aqueous, alcoholic or aqueous-alcoholic, or oily solution or suspension; a solution or a dispersion of a lotion or serum type; an emulsion, in particular of liquid or semi-liquid consistency, of O/W, W/O or multiple type (if the composition according to the present invention includes at least one oil); a suspension or emulsion of a soft consistency of cream (O/W) or (W/O) type; an aqueous gel, or any other cosmetic form.

The compositions according to the present invention may be in any galenical forms. For example, the compositions according to the present invention may be in the form of any treatment for hair in general, such as a cream, a lotion, a gel, and the like.

[Process]

The present invention also relates to a process for straightening keratin fibers, preferably hair, comprising the steps of:

(i) applying a composition onto the keratin fibers;

(ii) optionally rinsing off the keratin fibers with or without drying the keratin fibers after being rinsed off; and

(b) at least one organic acid metal salt; and

(c) water.

The details of the composition used in the process according to the present invention are the same as those explained in the section titled [Composition] above,

The process according to the present invention is for the purpose of straightening keratin fibers, such as hair, preferably straightening for a long period of time, and more preferably straightening even after shampooing several times. In this sense, the process according to the present invention can be a semi-permanent straightening process.

It is preferable that the keratin fibers be cleaned before the step (i). This cleaning step may be performed by, for example, shampooing the keratin fibers, followed by rinsing off the keratin fibers. After rinsing off, the keratin fibers may be dried. It is preferable that the keratin fibers are wet just before the step (i).

In step (i), the composition, which is described above, is applied to keratin fibers such as hair. The application of the composition may be performed by any means, such as a brush and a comb. The bath ratio of the applied composition to the keratin fibers may range from 0.1 to 10, more particularly from 0.5 to 5, and preferably between 0.8 and 2. The term "bath ratio" is intended to mean the weight ratio between the total weight of the applied composition and the total weight of the keratin fibers.

It may be possible that, after the application of the composition, the keratin fibers be left as they are for a certain amount of time; typically from 1 minute to 1 hour, preferably from 2 to 30 minutes, and more preferably from 3 to 10 minutes, if necessary, in order to let the composition penetrate into the keratin fibers.

After the step (i), the process according to the present invention may comprise an optional step (ii) of rinsing off the keratin fibers with or without drying the keratin fibers after being rinsed off.

Thus, if the step (ii) is present, the keratin fibers is rinsed off in order to remove the composition from the keratin fibers. The step of rinsing may be performed with water. It is preferable that the keratin fibers be dried after being rinsed off. The drying of the keratin fibers can be performed with a conventional drying means such as a hair dryer.

On the other hand, if the step (ii) is not present, the keratin fibers can be treated by the step (iii) after the step (i), without being rinsed off.

In the step (iii), the keratin fibers, which are preferably dry, are subjected to straightening at a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C, with a heater, preferably a heating iron, This temperature may be less than 250°C, preferably less than 240°C, and more preferably less than 230°C. Thus, this temperature may be more than 50°C and less than 250°C, preferably more than 100°C and less than 240°C, and more preferably more than 150°C and less than 230°C.

As the heating iron, any conventional heating iron can be used. The heating iron can have at least one plate, preferably two plates, which can be heated by, for example, electric heating. The heated plate(s) can be applied onto the keratin fibers and moved along with the direction of the keratin fibers to straighten them.

It is preferable that the heating iron has two plates, and that keratin fibers are sandwiched between the two plates of the heating iron, in which at least one of the plates can be heated, and then the two plates are moved along with the direction of the keratin fibers to straighten them.

It is preferable that the heating iron, in particular a part thereof contacting with keratin fibers, such as a heating plate or heating plates, has a temperature of more than 50°C and less than 250°C, more preferably more than 100°C and less than 240°C, and even more preferably more than 150°C and less than 230°C.

The step (iii) can be performed by one or more strokes of moving the heating iron along with the direction of keratin fibers. The step (iii) can be controlled by not only the temperature of the heating iron but also the number of strokes of the heating iron.

The heating time may depend on the temperature of the heating iron but also the number of strokes of the heating iron. It may be, for example, from 1 second to 10 minutes, and preferably from a few seconds to 5 minutes.

[Kit]

The present invention also relates to a kit for straightening keratin fibers such as hair, comprising: at least one heater which is capable of providing the keratin fibers with a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C; and at least one composition comprising

(b) at least one organic acid metal salt; and

(c) water.

The heater in the kit is not limited as long as it can heat keratin fibers at a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C. This temperature may be less than 250°C, preferably less than 240°C, and more preferably less than 230°C. Thus, this temperature may be more than 50°C and less than 250°C, preferably more than 100°C and less than 240°C, and more preferably more than 150°C and less than 230°C.

It is preferable that the heater be a heating iron as explained in the above [Process],

The above composition may further comprise (d) at least one betaine compound. The (d) betaine compound may be selected from the group consisting of trimethylglycine, carnitine, and L-proline betaine or stachydrine, and mixtures thereof.

The above explanations regarding the (a) compound, the (b) organic acid metal salt, and the (c) water, as well as the (d) betaine compound, can apply to those in the above composition used for the kit according to the present invention.

[Use]

(c) water in order to prevent or reduce color fading of the keratin fibers and/or lengthen the straightening effects for the keratin fibers by the composition, in particular in order to further maintain the straight shape of the keratin fibers, or prevent or reduce waving of the keratin fibers.

The heating is not limited as long as it can heat keratin fibers at a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C. This temperature may be less than 250°C, preferably less than 240°C, and more preferably less than 230°C. Thus, this temperature may be more than 50°C and less than 250°C, preferably more than 100°C and less than 240°C, and more preferably more than 150°C and less than 230°C.

The use of (b) at least one organic acid metal salt(s) can prevent or reduce the color change of keratin fibers, in particular dyed keratin fibers, due to the straightening by a composition comprising the (a) compound.

The use of (b) at least one organic acid metal salt(s) can lengthen or prolong the straightening effects for keratin fibers provided by the (a) compound.

The above explanations regarding the (a) compound, the (b) organic acid metal salt, and the (c) water, as well as the (d) betaine compound, can apply to those in the above composition used for the use according to the present invention.

EXAMPLES

The present invention will be described in a more detailed manner by way of examples.

However, these examples should not be construed as limiting the scope of the present invention.

Examples 1-9 and Comparative Examples 1-5

[Preparations]

Each of the compositions according to Examples 1-9 and Comparative Examples 1-5 was prepared by mixing the ingredients shown in Tables 1 and 2. The numerical values for the amounts of the ingredients are all based on “% by weight” as raw materials.

Table 1

Table 2

[Evaluations]

Coloring: A hair swatch of Chinese white natural hair, in a length of 27 cm was colored to warm brown color with an oxidative hair dye (L’Oreal Professional, Alluria Fashion Gray).

3 g of a mixture of the oxidative hair dye and a developer (L’Oreal Professional Alluria Cream Oxydant 6% H2O2) was applied onto 1g of the hair swatch, and the hair swatch was left for 30 minutes at a temperature of 27°C. The hair swatch was rinsed off and shampooed to complete the hair coloring process as a preparation before the shaping process.

Shaping: Next, 2g of each composition was applied onto lg of the hair swatch and left for 10 minutes at a temperature of 30°C. The hair swatch was rinsed off with running lukewarm water for 30 seconds, and dried by a hair dryer (Nobby NB3100, TESCOM DENKI Co., Ltd, Japan) until the hair swatch was dried completely. Then, the hair swatch was straightened by a heated hair iron (ADST-2, Hakko limited, Japan) at 180 °C for 3 strokes of 4 seconds, from the tip to root of the hair swatch.

Shampooing: Then, the hair swatch was wetted by running lukewarm water for 5 seconds with running a finger through it. The hair swatch (lg) was washed by 6 strokes of the finger through with 0.4g of a shampoo including 10.5% of sodium laureth sulfate, and rinsed off for 10 seconds with running a finger through it. The hair swatch was dried by the hair dryer until the hair swatch was dried completely.

(Color)

The values of L*a*b* (lightness / green-red I blue-yellow) of the hair swatch which had just been colored were measured by a spectrophotometer (CM-3600A, Konica Minolta, Japan). Four (4) points on the hair swatch were measured.

After the shaping and shampooing, the values of L*a*b* were measured again. AE* (between the color of the hair swatch before shaping and shampooing and the color of the hair swatch after shaping and shampooing based on CIE1976) was determined, A lower value of AE indicates less color fading.

The results are shown in the line labelled “Color” in Tables 1 and 2.

(Straightening Effects)

The straightening effects for the hair swatch provided by each composition, just after shaping, after shaping and shampooing 1 time, and after shaping and shampooing 7 times, were evaluated respectively by visual observation in accordance with the following criteria. The more the shape was maintained as straight, the higher value was given for this attribute.

6: Very straight from root to tip perfectly

5: Straight

4: Relatively straight and some curl observed

3 : Partially straight and curl observed

2: Less straight and more curl observed

1 : Curly

The results are showing in the lines labelled “Straightening Effects”, “Straightening Effects (after 1 shampoo)” and “Straightening Effects (after 7 shampoos)”in Tables 1 and 2.

(Frizz Control)

The frizz control performance for the hair swatch provided by each composition, just after shaping, after shaping and shampooing 1 time, and after shaping and shampooing 7 times, was evaluated by visual observation in accordance with the following criteria. When the hair has less frizz or less flyaway hairs, it has a higher score.

6: Frizz perfectly controlled, no flyaway hairs at all

5 : Frizz well controlled, no flyaway hairs observed

4: Frizz relatively controlled, very few flyaway hairs observed

3 : Frizz controlled partially, few flyaway hairs observed

2: Frizz slightly controlled, some flyaway hairs observed

1 : Frizz not controlled, many flyaway hairs observed

The results are shown in the lines labelled “Frizz Control”, “Frizz Control (after 1 shampoo)” and “Frizz Control (after 7 shampoos)”in Tables 1 and 2.

(Summary)

The compositions according to Examples 1-9 including: (a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylic acid salts, glyoxylic acid esters, glyoxylic acid amides, and mixtures thereof; (b) at least one organic acid metal salt; and (c) water, were able to reduce color fading of dyed keratin fibers by the straightening process, and were able to reduce loss of the straight shape of the straightened keratin fibers even after shampooing several times.

The compositions according to Comparative Examples 1-3 did not include the ingredient (a), and therefore, they could not maintain straightening effects even after 1 shampooing. The compositions according to Comparative Examples 4 and 5 did not include the ingredient (b), and therefore, they could not provide long-lasting straightening effects.

Claims

1. A composition for straightening keratin fibers, such as hair, with heating, comprising:

(b) at least one organic acid metal salt; and

(c) water.

2. The composition according to Claim 1 , wherein pH of the composition is 7 or less, preferably 6 or less, and more preferably 5 or less.

3. The composition according to Claim 1 or 2, wherein the amount of the (a) compound(s) in the composition is from 0.1% to 50% by weight, preferably from 0.5% to 40% by weight, and more preferably from 1% to 30% by weight, relative to the total weight of the composition.

4. The composition according to any one of Claims 1 to 3, wherein the metal of the (b) organic acid metal salt is selected from magnesium, calcium, and zinc.

5. The composition according to any one of Claims 1 to 4, wherein the organic acid of the (b) organic acid metal salt is selected from a-hydroxy acids, preferably selected from the group consisting of glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, and gluconic acid.

6. The composition according to any one of Claims 1 to 5, wherein the (b) organic acid metal salt is magnesium, calcium or zinc gluconate.

7. The composition according to any one of Claims 1 to 6, wherein the amount of the

(b) organic acid metal salt(s) in the composition is from 0.1% to 15% by weight, preferably from 0.2% to 10% by weight, and more preferably from 0.3% to 5% by weight, relative to the total weight of the composition.

8. The composition according to any one of Claims 1 to 7, wherein the amount of the

(c) water in the composition is from 20% to 99% by weight, preferably from 30% to 95% by weight, and more preferably from 40% to 90% by weight, relative to the total weight of the composition.

9. The composition according to any one of Claims 1 to 8, wherein the composition further comprises (d) at least one betaine compound, preferably selected from the group consisting of trimethylglycine, carnitine, and L-proline betaine or stachydrine, and mixtures thereof.

10. The composition according to Claim 9, wherein the amount of the (d) betaine compound(s) in the composition is from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight, relative to the total weight of the composition.

11. The composition according to any one of Claims 1 to 10, wherein the composition does not comprise any ammonia or a thiol compound, or comprises less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of ammonia or a thiol compound, relative to the total weight of the composition.

12. The composition according to any one of Claims 1 to 11, wherein the composition does not comprise any reducing agent or oxidizing agent, or comprises less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of a reducing agent or an oxidizing agent, relative to the total weight of the composition.

13. A process for straightening keratin fibers, such as hair, comprising the steps of:

(i) applying a composition onto the keratin fibers;

(b) at least one organic acid metal salt; and

(c) water.

14. A kit for straightening keratin fibers such as hair, comprising: at least one heater, preferably a heating iron, which is capable of providing the keratin fibers with a temperature of more than 50°C, preferably more than 100°C, and more preferably more than 150°C; and at least one composition comprising

(b) at least one organic acid metal salt; and

(c) water.

15. A use of (b) at least one organic acid metal salt in a composition for straightening keratin fibers such as hair, with heating, comprising: