Improved straightening method for keratin fibres

Abstract

The present invention relates to a method for correcting keratin fibres, such as the hair, comprising the steps of: (i) applying a composition to the keratin fibres; (ii) optionally rinsing the keratin fibres, drying or not drying the keratin fibres after rinsing; and (iii) right-angled protein fibers at a temperature higher than 50 DEG C, preferably higher than 100 DEG C and more preferably higher than 150 DEG C, wherein the composition comprises (a) at least one compound selected from the group consisting of: (a) at least one compound selected from the group consisting of glyoxylic acid, glyoxylic acid solvates, glyoxylate salts, glyoxylate esters, glyoxylic acid amides, and mixtures thereof; (b) at least one betaine compound; and (c) water. The present invention can improve a method for straightening keratin fibers (e.g., the hair) based on heating keratin fibers with glyoxylic acid or a derivative thereof by providing a more durable straightening effect.

Description

Technical Field

[0001] The present invention relates to a method for straightening keratin fibers (such as hair), in particular a cosmetic method. Background Art

[0002] Straightening keratin fibers (such as hair) by heating them with an iron is popular because it makes frizzy keratin fibers easier to manage, gives the keratin fibers less volume and makes them look more desirable. This straightening method using a heated iron is convenient for quick styling, but the styling only lasts for a short period of time, such as until the next shampooing. Many consumers require a long-lasting straightening method.

[0003] On the other hand, traditional permanent straightening methods utilize heating with reducing agents and alkalis as well as oxidizing agents, which can provide a long-lasting styling for keratin fibers, but they have several drawbacks, such as long processing times, damage to the keratin fibers, and foul odors.

[0004] WO2014 / 131469 discloses a method for straightening keratin fibers by heating with an iron, without using reducing agents and oxidizing agents, in which glyoxylic acid is used to straighten the keratin fibers. Summary of the Invention

[0005] There is still a need to improve the straightening of keratin fibers based on heating them with glyoxylic acid or its derivatives.

[0006] The object of the present invention is to provide an improved method for straightening keratin fibers (such as hair), which is based on heating the keratin fibers together with glyoxylic acid or its derivatives, and which can provide a more long-lasting straightening effect for the keratin fibers.

[0007] The above object of the present invention can be achieved by a method for straightening keratin fibers (such as hair), which comprises the following steps:

[0008] (i) applying a composition to the keratin fibers;

[0009] (ii) optionally rinsing the keratin fibers, and drying or not drying the keratin fibers after rinsing; and

[0010] (iii) straightening the keratin fibers at a temperature above 50°C, preferably above 100°C and more preferably above 150°C,

[0011] wherein

[0012] the composition comprises

[0013] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof;

[0014] (b) at least one betaine compound; and

[0015] (c) water.

[0016] Preferably, the above composition is applied to wet keratin fibers.

[0017] The pH of the above composition can be 7 or below, preferably 6 or below, and more preferably 5 or below.

[0018] In the above composition, the amount of the compound(s) of (a) can be 0.1% to 50% by weight, preferably 0.5% to 40% by weight, and more preferably 1% to 30% by weight based on the total weight of the composition.

[0019] (b) The betaine compound can be selected from glycine betaine, carnitine, L-proline betaine or stachydrine, and mixtures thereof.

[0020] (b) The amount of the betaine compound(s) in the above composition can be 0.01% to 15% by weight, preferably 0.05% to 10% by weight, and more preferably 0.1% to 5% by weight based on the total weight of the composition.

[0021] (c) The amount of water in the above composition can be 20% to 99% by weight, preferably 30% to 95% by weight, and more preferably 40% to 90% by weight based on the total weight of the composition.

[0022] The above composition may further comprise (d) at least one compound different from the compound(s) of (a), selected from keto acids, their salts, and mixtures thereof.

[0023] (d) The compound can be selected from levulinic acid, its salts, and mixtures thereof.

[0024] (d) The amount of the compound in the above composition can be 0.1% to 15% by weight, preferably 0.5% to 10% by weight, and more preferably 1% to 5% by weight based on the total weight of the composition.

[0025] The above composition may not contain any ammonia or thiol compounds, or may contain less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of ammonia or thiol compounds based on the total weight of the composition.

[0026] The above composition may not contain any reducing agent or oxidizing agent, or may contain less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of reducing agent or oxidizing agent based on the total weight of the composition.

[0027] The present invention also relates to a composition for straightening keratin fibers (such as hair) by heating, which comprises:

[0028] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvate, glyoxylate, glyoxylate ester, glyoxamide, and mixtures thereof;

[0029] (b) at least one betaine compound; and

[0030] (c) water.

[0031] The present invention also relates to a kit for straightening keratin fibers (such as hair), which comprises:

[0032] at least one heater, preferably a heated iron, which is capable of providing a temperature higher than 50 °C, preferably higher than 100 °C, and more preferably higher than 150 °C to the keratin fibers; and

[0033] at least one composition, which comprises

[0034] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvate, glyoxylate, glyoxylate ester, glyoxamide, and mixtures thereof;

[0035] (b) at least one betaine compound; and

[0036] (c) water.

[0037] The present invention also relates to the use of (b) at least one betaine compound in a composition for straightening keratin fibers (such as hair) by heating, the composition comprising:

[0038] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvate, glyoxylate, glyoxylate ester, glyoxamide, and mixtures thereof; and

[0039] (c) water,

[0040] wherein the use is for prolonging the straightening effect of the composition on the keratin fibers, in particular for further maintaining the straight shape of the keratin fibers, or for preventing or reducing the waving of the keratin fibers.

[0041] Best mode for carrying out the present invention

[0042] Through diligent research, the inventors have found that an improved method for straightening keratin fibers (such as hair) can be provided, which is based on heating the keratin fibers together with glyoxylic acid or its derivatives, and this can provide a more lasting straightening effect for the keratin fibers.

[0043] Accordingly, the present invention mainly relates to a method for straightening keratin fibers (such as hair), which comprises the following steps:

[0044] (i) applying the composition to the keratin fibers;

[0045] (ii) optionally rinsing the keratin fibers and drying or not drying the keratin fibers after rinsing; and

[0046] (iii) straightening the keratin fibers at a temperature above 50 °C, preferably above 100 °C and more preferably above 150 °C,

[0047] wherein

[0048] the composition comprises

[0049] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof;

[0050] (b) at least one betaine compound; and

[0051] (c) water.

[0052] The present invention can improve the method for straightening keratin fibers (such as hair) by providing a more lasting straightening effect, which is based on heating the keratin fibers together with glyoxylic acid or its derivatives.

[0053] The present invention can provide a more lasting straightening effect for keratin fibers (such as hair). Therefore, the present invention can lengthen or extend the straightening effect on keratin fibers provided by using a composition containing only glyoxylic acid or its derivatives. Specifically, the present invention can further maintain the straightened shape of keratin fibers, or can prevent or reduce the loss of the straightened shape of keratin fibers over time.

[0054] For example, if the keratin fibers are originally wavy, after straightening the keratin fibers, especially after washing with shampoo, the present invention can better prevent the keratin fibers from returning to their original wavy shape.

[0055] In the present invention, using at least one betaine compound can increase or extend the straightening effect on keratin fibers provided by glyoxylic acid or its derivatives. Specifically, using at least one betaine compound can further maintain the straightened shape of keratin fibers provided by glyoxylic acid or its derivatives, or can prevent or reduce the curling of keratin fibers.

[0056] The present invention can also provide a sufficient immediate straightening effect for keratin fibers. Therefore, keratin fibers treated with the present invention have a smaller volume and less frizz due to a reduction in the curl of the keratin fibers. The straightening effect provided by the present invention can last for a long time, for example, even after washing the keratin fibers with a shampoo. Therefore, the present invention can also provide a shape of keratin fibers that is well-tolerant to washing with a shampoo.

[0057] Since the present invention does not require the use of any reducing agent / oxidizing agent, compared with traditional straightening methods, the present invention can provide keratin fibers with less damage. Therefore, keratin fibers treated with the present invention can be easily combed. Thus, keratin fibers treated with the present invention can be easily managed. In addition, keratin fibers treated with the present invention can be stronger than keratin fibers treated with traditional straightening methods.

[0058] In addition, the present invention can be used without or with a very small amount of ammonia or thiol compounds, and thus, compared with traditional methods that require the use of ammonia or thiol compounds, the odor during the use of the present invention can be reduced. In addition, the present invention can have good usability, for example, a short treatment time.

[0059] The present invention will be described in detail hereinafter.

[0060] [Method]

[0061] The present invention relates to a method for straightening keratin fibers (preferably hair), which comprises the following steps:

[0062] (i) Applying a composition to the keratin fibers;

[0063] (ii) Optionally rinsing the keratin fibers, and drying or not drying the keratin fibers after rinsing; and

[0064] (iii) Straightening the keratin fibers at a temperature higher than 50°C, preferably higher than 100°C, and more preferably higher than 150°C,

[0065] wherein

[0066] the composition comprises

[0067] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof;

[0068] (b) at least one betaine compound; and

[0069] (c) water.

[0070] Details of the composition used in the method according to the present invention will be described in the section hereinafter entitled [Composition].

[0071] The method according to the present invention is for straightening keratin fibers (such as hair), preferably maintaining the straightening for a long period of time, and more preferably maintaining the straightening even after being washed with shampoo several times. In this sense, the method according to the present invention can be a semi-permanent straightening method.

[0072] Preferably, the keratin fibers are cleaned before step (i). This cleaning step can be carried out, for example, by washing the keratin fibers with shampoo and then rinsing the keratin fibers. After rinsing, the keratin fibers can be dried. Preferably, just before step (i), the keratin fibers are wet.

[0073] In step (i), the composition to be described subsequently is applied to the keratin fibers, such as hair. The application of the composition can be carried out in any manner, such as by brush and comb.

[0074] The bath ratio of the applied composition to the keratin fibers can be from 0.1 to 10, more specifically from 0.5 to 5, and preferably from 0.3 to 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.

[0075] It is possible that after applying the composition, if necessary, the keratin fibers remain in place for a certain amount of time; usually from 1 minute to 1 hour, preferably from 2 minutes to 30 minutes, and more preferably from 3 minutes to 10 minutes, so that the composition penetrates into the keratin fibers.

[0076] After step (i), the method according to the present invention can include an optional step (ii) of rinsing the keratin fibers, and the keratin fibers are dried or not dried after rinsing.

[0077] Therefore, if step (ii) exists, the keratin fibers are rinsed to remove the composition from the keratin fibers. The rinsing step can be carried out with water. Preferably, the keratin fibers are dried after rinsing. The drying of the keratin fibers can be carried out by a conventional drying method (such as a hair dryer).

[0078] On the other hand, if step (ii) does not exist, the keratin fibers can be processed in step (iii) without rinsing after step (i).

[0079] In step (iii), the keratin fibers, which are preferably dry, are straightened with a heater (preferably a heated iron) at a temperature above 50 °C, preferably above 100 °C, and more preferably above 150 °C. The temperature can be lower than 250 °C, preferably lower than 240 °C, and more preferably lower than 230 °C. Thus, the temperature can be above 50 °C and below 250 °C, preferably above 100 °C and below 240 °C, and more preferably above 150 °C and below 230 °C.

[0080] As the heated iron, any conventional heated iron can be used. The heated iron can have at least one plate, preferably two plates, which can be heated, for example, by electric heating. The (one or more) heated plates can be applied to the keratin fibers and moved along the direction of the keratin fibers to straighten them.

[0081] Preferably, the heated iron has two plates, and the keratin fibers are sandwiched between the two plates of the heated iron, where at least one plate can be heated, and then the two plates are moved along the direction of the keratin fibers to straighten them.

[0082] Preferably, the heated iron, especially the part thereof in contact with the keratin fibers, such as one or more heated plates, has a temperature greater than 50 °C and less than 250 °C, more preferably greater than 100 °C and less than 240 °C, and even more preferably greater than 150 °C and less than 230 °C.

[0083] Step (iii) can be carried out by moving the heated iron one or more strokes along the direction of the keratin fibers. Step (iii) can be controlled not only by the temperature of the heated iron but also by the number of strokes of the heated iron.

[0084] The heating time can depend on the temperature of the heated iron or on the number of strokes of the heated iron. For example, it can range from 1 second to 10 minutes, and preferably from a few seconds to 5 minutes.

[0085] [Composition]

[0086] The composition for use in the method according to the invention or the composition for straightening keratin fibers according to the invention comprises:

[0087] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof;

[0088] (b) at least one betaine compound; and

[0089] (c) water.

[0090] Preferably, the above composition is a cosmetic composition, more preferably a cosmetic composition for straightening keratin fibers, and even more preferably a cosmetic composition for straightening keratin fibers in one step. Particularly preferably, the keratin fibers are hair.

[0091] (Glyoxylic acid and its derivatives)

[0092] The composition for use in the present invention comprises (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof.

[0093] A single type of (a) compound may be used, but two or more different types of (a) compounds may also be used in combination.

[0094] (a) Compounds are selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof. In other words, (a) compounds are selected from glyoxylic acid and its derivatives.

[0095] As glyoxylic acid solvates, mention may be made, for example, of glyoxylic acid hydrates, such as glyoxylic acid monohydrate.

[0096] As glyoxylates, mention may be made, for example, of alkali metal salts or alkaline earth metal salts of glyoxylic acid, such as sodium glyoxylate or potassium glyoxylate, and magnesium glyoxylate or calcium glyoxylate.

[0097] As glyoxylates, mention may be made, for example, of alkyl glyoxylates, such as methyl glyoxylate and ethyl glyoxylate.

[0098] As glyoxylamides, mention may be made, for example, of N-glyoxyloylcarbocysteine and N-glyoxyl keratin amino acids.

[0099] Preferably, glyoxylic acid is used as the (a) compound.

[0100] The amount of the (a) compound(s) in the composition for use in 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, based on the total weight of the composition.

[0101] On the other hand, the amount of the (a) compound(s) in the composition for use in the present invention may be 50% by weight or less, preferably 40% by weight or less, and more preferably 30% by weight or less, based on the total weight of the composition.

[0102] The amount of the compound(s) (a) in the composition for use in 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, based on the total weight of the composition.

[0103] (Betaine compound)

[0104] The composition for use in the present invention comprises (b) at least one betaine compound. A single type of (b) betaine compound may be used, but two or more different types of (b) betaine compounds may also be used in combination.

[0105] The term "betaine compound" as used herein refers to an amphoteric compound having a positively charged cationic moiety and a negatively charged anionic moiety, wherein no hydrogen atom in the positively charged cationic moiety is bonded to the positively charged atom, and the positively charged cationic moiety may not be adjacent to the negatively charged anionic moiety.

[0106] For the purposes of the present invention, the (b) betaine compound herein is not a surfactant, which comprises at least one hydrophilic moiety and at least one hydrophobic moiety.

[0107] In the (b) betaine compound, the positively charged cationic moiety includes, but is not limited to, a quaternary ammonium cation, a phosphonium cation, and a sulfonium cation. Preferably, the (b) betaine compound comprises a quaternary ammonium cation as the positively charged cationic moiety.

[0108] The negatively charged anionic moiety in the (b) betaine compound includes, but is not limited to, a carboxylate anion.

[0109] The (b) betaine compound may be selected from glycine betaine, carnitine, L-proline betaine or stachydrine, and mixtures thereof, and may preferably be glycine betaine.

[0110] The amount of the betaine compound(s) (b) in the composition for use in 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, based on the total weight of the composition. Even more preferably, the amount of the betaine compound(s) (b) in the composition for use in the present invention is 0.2% by weight or more, based on the total weight of the composition.

[0111] On the other hand, the amount of the (b) (one or more) betaine compounds in the composition for use in the present invention can 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. Even more preferably, the amount of the (b) (one or more) betaine compounds in the composition for use in the present invention is 3% by weight or less relative to the total weight of the composition.

[0112] The amount of the (b) (one or more) betaine compounds in the composition for use in the present invention can be from 0.01% by weight to 15% by weight, preferably from 0.05% by weight to 10% by weight, and more preferably from 0.1% by weight to 5% by weight, relative to the total weight of the composition. Even more preferably, the amount of the (b) (one or more) betaine compounds in the composition for use in the present invention is from 0.2% by weight to 3% by weight relative to the total weight of the composition.

[0113] (Water)

[0114] The composition for use in the present invention comprises (c) water.

[0115] Therefore, the composition for use in the present invention is not anhydrous.

[0116] The amount of (c) water in the composition for use in the present invention is 20% by weight or more, preferably 30% by weight or more, and more preferably 40% by weight, relative to the total weight of the composition.

[0117] On the other hand, the amount of (c) water in the composition for use in the present invention can 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.

[0118] The amount of (c) water in the composition for use in the present invention can be from 20% by weight to 99% by weight, preferably from 30% by weight to 95% by weight, and more preferably from 40% by weight to 90% by weight, relative to the total weight of the composition.

[0119] (Keto acid)

[0120] The composition for straightening keratin fibers for use in the present invention can comprise (d) at least one compound different from the (a) compound, selected from keto acids, their salts, and mixtures thereof. Two or more of the (d) compounds can be used in combination. Thus, a single type of (d) compound or a combination of different types of (d) compounds can be used.

[0121] The keto acid can be selected from α-keto acids, β-keto acids, γ-keto acids, and mixtures thereof.

[0122] The α-keto acid can be a compound represented by the general formula (I):

[0123] R 1 -C(=O)-COOH (I)

[0124] wherein

[0125] R 1 represents a straight-chain or branched C1-C6 alkyl group, optionally substituted by OH, COOH or a halogen atom (such as a chlorine or bromine atom).

[0126] Examples of α-keto acids include pyruvic acid.

[0127] β-keto acids can be represented by the general formula (II):

[0128] R 2 -C(=O)-R 3 -COOH (II)

[0129] wherein

[0130] R 2 represents a straight-chain or branched C1-C6 alkyl group, optionally substituted by OH, COOH or a halogen atom (such as a chlorine or bromine atom); and

[0131] R 3 represents a methylene group, optionally substituted by a halogen atom (such as a chlorine or bromine atom).

[0132] Examples of β-keto acids include acetoacetic acid.

[0133] γ-keto acids can be represented by the general formula (III):

[0134] R 2 -C(=O)-R 4 -COOH (III)

[0135] wherein

[0136] R 2 represents a straight-chain or branched C1-C6 alkyl group, optionally substituted by OH, COOH or a halogen atom (such as a chlorine or bromine atom); and

[0137] R 4 represents an ethylene group, optionally substituted by a halogen atom (such as a chlorine or bromine atom).

[0138] Examples of γ-keto acids include levulinic acid.

[0139] The salts of keto acids can be alkali metal salts or alkaline earth metal salts of keto acids, such as sodium salts or potassium salts of keto acids, and magnesium salts or calcium salts of keto acids.

[0140] Preferably, a γ-keto acid is used, and more preferably levulinic acid and / or its salt, such as sodium levulinate, is used as the compound(s) (d).

[0141] In the composition for use in the present invention, the amount of the compound(s) (d) can be 0.1% by weight or more, preferably 0.5% by weight or more, and more preferably 1% by weight or more, based on the total weight of the composition.

[0142] On the other hand, in the composition for use in the present invention, the amount of the compound(s) (d) can be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, based on the total weight of the composition.

[0143] In the composition for use in the present invention, the amount of the compound(s) (d) can be from 0.1% by weight to 15% by weight, preferably from 0.5% by weight to 10% by weight, and more preferably from 1% by weight to 5% by weight, based on the total weight of the composition.

[0144] (pH)

[0145] The composition for use in the present invention can have a pH of 7 or lower, preferably 6 or lower, and more preferably 5 or lower, measured at 25°C.

[0146] The composition for use in the present invention can have a pH of 3 or higher, measured at 25°C.

[0147] The composition for use in the present invention can have a pH of from 3 to 7, preferably from 3 to 6, and more preferably from 3 to 5, measured at 25°C.

[0148] (Alkalizing agent)

[0149] The composition for straightening keratin fibers for use in the present invention can comprise at least one alkalizing agent. Two or more alkalizing agents can be used in combination. Thus, a single type of alkalizing agent or a combination of different types of alkalizing agents can be used.

[0150] The alkalizing agent is different from the (b) betaine compound.

[0151] If the (a) compound can act to lower the pH of the composition, preferably the composition for use in the present invention comprises the alkalizing agent(s).

[0152] The alkalizing agent can be an inorganic alkalizing agent. Preferably, the alkalizing agent is non-volatile. Preferably, the inorganic alkalizing agent is selected from alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal phosphates and monohydrogen alkali metal phosphates, such as sodium phosphate or monohydrogen sodium phosphate.

[0153] Examples of the inorganic alkali metal hydroxides include sodium hydroxide, lithium hydroxide, and potassium hydroxide. Examples of the alkaline earth metal hydroxides include calcium hydroxide and magnesium hydroxide. As the inorganic base agent, sodium hydroxide and potassium hydroxide are preferred.

[0154] The base agent may be an organic base agent. Preferably, the organic base agent is selected from primary amines and secondary amines.

[0155] Examples of the primary amine include alkanolamines such as mono-, di-, and triethanolamines containing 1 to 3 hydroxyalkyl (C1-C4) groups. In particular, the alkanolamine may be selected from monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, N,N-dimethylethanolamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, 2-amino-2-methyl-1,3-propanediol, 3-amino-1,2-propanediol, 3-dimethylamino-1,2-propanediol, and tris(hydroxymethyl)aminomethane.

[0156] The secondary amine can be described by the following structure (B):

[0157]

[0158] wherein W represents an alkylene group, such as a propylene group optionally substituted with a hydroxyl group or a C1-C4 alkyl group, and R a 、R b 、R c and R d independently represent a hydrogen atom, an alkyl group, or a C1-C4 hydroxyalkyl group, which can be exemplified by 1,3-propanediamine and its derivatives.

[0159] In the composition for use in the present invention, the amount of the base agent(s) may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more based on the total weight of the composition.

[0160] On the other hand, in the composition for use in the present invention, the amount of the base agent(s) may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less based on the total weight of the composition.

[0161] The base agent(s) may be used in a total amount of 0.01% by weight to 15% by weight, preferably 0.05% by weight to 10% by weight, and more preferably 0.1% by weight to 5% by weight based on the total weight of the composition.

[0162] (Acid)

[0163] The composition for straightening keratin fibers according to the invention may comprise at least one acid different from the (a) compound or the (b) 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.

[0164] The acid may be used to adjust the pH of the composition according to the invention.

[0165] If the (a) compound can act to raise the pH of the composition, it is preferred that the composition according to the invention comprises the (one or more) acids.

[0166] As the acid, any inorganic acid or organic acid commonly used in cosmetics may be mentioned, such as citric acid, lactic acid, sulfuric acid, phosphoric acid or hydrochloric acid (HCl). HCl is preferred.

[0167] The amount of the (one or more) acids in the composition according to the 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, based on the total weight of the composition.

[0168] On the other hand, the amount of the (one or more) acids in the composition according to the invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, based on the total weight of the composition.

[0169] The (one or more) acids may be used in a total amount of 0.01% by weight to 15% by weight, preferably 0.05% by weight to 10% by weight, and more preferably 0.1% by weight to 5% by weight, based on the total weight of the composition.

[0170] (Other optional ingredients)

[0171] The composition according to the invention may further comprise at least one other optional ingredient, particularly selected from: oils, preferably polar oils, and more preferably ester oils, in liquid form at 25 °C at atmospheric pressure; solid fatty substances, and in particular C8-C 40 esters, C8-C 40 acids and C8-C 40 alcohols, at 25 °C at atmospheric pressure; thickeners; sunscreens; moisturizers; antidandruff agents; antioxidants; chelating agents; pearlescents and opacifiers; plasticizers or coalescers; fillers; emulsifiers; polymers (particularly conditioning polymers, such as cationic polymers); fragrances; silanes; crosslinking agents; surfactants (including anionic, cationic, amphoteric and nonionic surfactants). Of course, the composition may comprise several cosmetic ingredients from the list mentioned above.

[0172] The composition for use in the present invention may include one or several cosmetically acceptable organic solvents, which may be alcohols: especially monohydric alcohols such as ethanol, isopropanol, benzyl alcohol and phenethyl alcohol; diols such as ethylene glycol, propylene glycol and octanediol; other polyhydric alcohols such as glycerol; and ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and propylene glycol monobutyl ether, and butylene glycol monomethyl ether, butylene glycol monoethyl ether and butylene glycol monobutyl ether.

[0173] Depending on their nature and the intention of the composition, the above-mentioned optional (one or more) components may be present in normal amounts readily determinable by those skilled in the art, and for each component, the normal amount may be from 0.01% by weight to 80% by weight. Those skilled in the art will carefully select the components included in the composition and their amounts such that they do not impair the properties of the composition for use in the present invention.

[0174] (Ammonia and thiol compounds)

[0175] Preferably, the composition for use in the present invention does not contain ammonia or thiol compounds. The term "does not contain ammonia or thiol compounds" means that the composition for use in the present invention does not include a large amount of ammonia or thiol compounds. Preferably, the composition for use in 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 thiol compounds, especially no ammonia or thiol compounds.

[0176] Due to the extremely small amount or absence of ammonia and / or thiol compounds, malodor can be reduced or prevented during the use of the composition for use in the present invention.

[0177] Herein, thiol compounds mean compounds having at least one mercapto (-SH) group.

[0178] Thiol compounds can be reducing agents. Thiol reducing agents can be selected from: mercaptoacetic acid and its derivatives, especially its esters such as monoglycerol mercaptoacetate or ethylene glycol ester; thiolactic acid and its derivatives, especially its esters such as monoglycerol thiolactate; 3-mercaptopropionic acid and its derivatives, especially its esters such as glycerol 3-mercaptopropionate and ethylene glycol 3-mercaptopropionate; cysteamine and its derivatives, especially its C1-C4 acyl derivatives such as N-acetylcysteamine and N-propionylcysteamine; monothioglycerol and its derivatives, especially esters; cysteine and its derivatives, especially esters such as N-acetylcysteine, N-alkanoyl cysteine and cysteine alkyl esters; thioglycerol and its derivatives, especially S-alkyl derivatives, and their salts.

[0179] As said salts, mention may be made, for example, of ammonium salts, primary, secondary or tertiary amine salts, alkali metal salts and alkaline earth metal salts. As primary, secondary or tertiary amines, mention may be made, respectively, of, for example, monoethanolamine, diisopropanolamine or triethanolamine.

[0180] Other examples of thiol reducing agents include, but are not limited to: sugar N-mercaptoalkylamides, such as N-(mercapto-2-ethyl)glucamide; β-mercaptopropionic acid and its derivatives; thiomalic acid; pantheteine; N-(mercaptoalkyl)ω-hydroxyalkylamides, such as those described in European patent application No. 0354835, and N-mono- or N,N-dialkylmercapto 4-butyramides, such as those described in European patent application No. 0368763; amino mercaptoalkylamides, such as those described in European patent application No. 0432000, and alkylamino mercaptoalkylamides, such as those described in European patent application No. 0514282; (2 / 3)hydroxy-2-propyl mercaptoacetate; and mixtures (67 / 33) based on hydroxy-2-methyl-1-ethyl mercaptoacetate as described in French patent application No. 2679448.

[0181] (Reducing agents and oxidizing agents)

[0182] The compositions for use in the present invention may contain a reducing agent. However, it is preferred that the compositions for use in the present invention contain a reduced amount of a reducing agent or an oxidizing agent, preferably no reducing agent or oxidizing agent.

[0183] The term "no reducing agent or oxidizing agent" means that the compositions for use in the present invention do not contain a large amount of a reducing agent or an oxidizing agent. Preferably, the compositions for use in the present invention contain 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, especially no reducing agent or no oxidizing agent.

[0184] The reducing agent may be a thiol reducing agent or a non-thiol reducing agent. Thiol reducing agents are as described above.

[0185] Herein, a non-thiol reducing agent means a reducing agent that does not have a mercapto group. Non-thiol reducing agents may be selected from sulfites, bisulfites, sulfinates, phosphines, sugars, reductones and hydrides. Non-thiol reducing agents may be selected from ammonium sulfite and ammonium bisulfite and metal sulfites and bisulfites, more preferably alkali metal or alkaline earth metal sulfites and bisulfites, and more preferably sodium sulfite and sodium bisulfite.

[0186] The oxidizing agent may be selected from hydrogen peroxide, alkali metal bromates, ferricyanides, peroxy salts and compounds capable of generating hydrogen peroxide by hydrolysis. For example, the oxidizing agent may be selected from aqueous hydrogen peroxide, carbamide peroxide, alkali metal bromates and peracids (such as perborates and persulfates).

[0187] (Form)

[0188] The compositions for use in the present invention can be in any form suitable for topical application and, in particular, in the following forms: aqueous solutions, alcoholic solutions, hydroalcoholic solutions or oily solutions or suspensions; solutions or dispersions of the lotion or serum type; emulsions, especially of the O / W, W / O or multiple types (if the composition for use in the present invention includes at least one oil) of liquid or semi-liquid consistency; suspensions or emulsions of soft consistency of the cream (O / W) or (W / O) type; hydrogels, or any other cosmetic form.

[0189] The compositions for use in the present invention can be in any galenical form. For example, the compositions for use in the present invention can be in any form generally used for hair treatment, such as creams, lotions, gels, etc.

[0190] [Kit]

[0191] The present invention also relates to a kit for straightening keratin fibers (such as hair), which comprises:

[0192] at least one heater capable of providing a temperature higher than 50 °C, preferably higher than 100 °C, and more preferably higher than 150 °C to the keratin fibers; and

[0193] at least one composition comprising

[0194] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof;

[0195] (b) at least one betaine compound; and

[0196] (c) water.

[0197] The heater in the kit is not limited as long as it can heat the keratin fibers at a temperature higher than 50 °C, preferably higher than 100 °C, and more preferably higher than 150 °C. This temperature can be lower than 250 °C, preferably lower than 240 °C, and more preferably lower than 230 °C. Thus, this temperature can be higher than 50 °C and lower than 250 °C, preferably higher than 100 °C and lower than 240 °C, and more preferably higher than 150 °C and lower than 230 °C.

[0198] Preferably, the heater is a soldering iron as described in the above [Method].

[0199] The above composition may further comprise (d) at least one compound different from the (a) compound, which is selected from keto acids, their salts, and mixtures thereof. The (d) compound can be selected from levulinic acid, its salts, and mixtures thereof.

[0200] The above explanations of (a) a compound, (b) a betaine compound, and (c) water and (d) a compound can be applied to the above compositions for the kits according to the present invention.

[0201] [Use]

[0202] The present invention also relates to the use of (b) at least one betaine compound in a composition for straightening keratin fibers (such as hair) by heating, the composition comprising:

[0203] (b) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof; and

[0204] (c) water

[0205] The use is for prolonging the straightening effect of the composition on keratin fibers, in particular for further maintaining the straightened shape of keratin fibers or preventing or reducing the curling of keratin fibers.

[0206] There is no limitation on heating as long as it can heat keratin fibers at a temperature above 50°C, preferably above 100°C, and more preferably above 150°C. The temperature can be below 250°C, preferably below 240°C, and more preferably below 230°C. Therefore, the temperature can be above 50°C and below 250°C, preferably above 100°C and below 240°C, and more preferably above 150°C and below 230°C.

[0207] (b) The use of at least one betaine compound can increase or prolong the straightening effect on keratin fibers provided by (a) the compound.

[0208] The above composition may further comprise (d) at least one compound different from (a) the compound, selected from keto acids, their salts, and mixtures thereof. The (d) compound can be selected from levulinic acid, its salts, and mixtures thereof.

[0209] The above explanations of (a) the compound, (b) the betaine compound and (c) water, and (d) the compound can be applied to those components in the above composition for the use according to the present invention.

[0210] [Additional Invention]

[0211] The object of the present invention can also be achieved by a method for straightening keratin fibers (such as hair), the method comprising the following steps:

[0212] (i) applying the composition to the keratin fibers;

[0213] (ii) optionally rinsing the keratin fibers and drying or not drying the keratin fibers after rinsing; and

[0214] (iii) Keratin fibers are straightened at a temperature above 50 °C, preferably above 100 °C, and more preferably above 150 °C.

[0215] wherein

[0216] the composition comprises

[0217] (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof, in an amount greater than 5% by weight, preferably greater than 6% by weight, and more preferably greater than 7% by weight based on the total weight of the composition.

[0218] (c) water; and

[0219] (d) at least one compound different from the compound of (a), selected from keto acids (especially levulinic acid), its salts, and mixtures thereof, in an amount of 0.1% to 15% by weight, preferably 0.5% to 10% by weight, and more preferably 1% to 5% by weight based on the total weight of the composition.

[0220] The above description of the compound (a), water (c), and compound (d) of the composition for the method according to the invention can be applied to those components in the above composition for the above method.

[0221] The above composition does not need to include (b) at least one betaine compound.

[0222] The above method can also achieve the following effects: (1) Keratin fibers treated by the above method can provide a soft and moisturizing feel, as well as elasticity. (2) Keratin fibers treated by the above method are easy to manage. (3) Even after washing with shampoo, the above method can still prevent keratin fibers from returning to their original shape before the method, and / or (4) Keratin fibers treated by the above method can better maintain the straightened shape even under humid conditions. Examples

[0223] The present invention will be described in more detail by way of examples. However, these examples should not be construed as limiting the scope of the present invention.

[0224] Examples 1-6 and Comparative Examples 1-5

[0225] [Preparation]

[0226] Each composition according to Examples 1-6 and Comparative Examples 1-5 was prepared by mixing the components shown in Table 1. The numerical values of the amounts of the components are all based on "weight %" of the raw materials.

[0227]

[0228] [Evaluation]

[0229] Each of the above compositions is used to straighten a hair sample, and then the hair sample is evaluated according to the following protocol.

[0230] 1) Shampoo a hair sample of 27 cm long Chinese black, natural, slightly curly hair with the SLS shampoo composition shown in Table 2 below. Thoroughly rinse the hair sample with tap water.

[0231] Table 2

[0232] wt% Hexylene glycol 1 Sodium chloride 1 Water qsp100 Cocamidopropyl betaine 9 Sodium laureth sulfate (70 wt%) 15 Salicylic acid 0.2 Sodium benzoate 0.5 Polyquaternium-10 0.3

[0233] 2) Apply each of the compositions according to Examples 1 - 6 and Comparative Examples 1 - 5 in an amount of 2 g to the wet hair sample.

[0234] 3) Leave the hair sample at room temperature (25 °C) for 10 minutes.

[0235] 4) Thoroughly rinse the hair sample with tap water.

[0236] 5) Dry the hair sample with a hair dryer (Nobby NB3100, TESCOM DENKI Co., Ltd, Japan) for about 90 seconds until dry.

[0237] 6) Straighten the hair sample with a hair straightening iron (ADST Premium DS2, Hakko Limited, Japan) at 180 °C for 3 passes, 4 seconds per pass.

[0238] 7) Immediately after step 6, visually evaluate the degree of straightening of the hair sample (straightening effect at T0) according to the following criteria.

[0239] 5: Very good

[0240] 4: Good

[0241] 3: Fair

[0242] 2: Poor

[0243] 1: Very poor

[0244] The results are shown in "Straightening effect (T0)" in Table 1.

[0245] 8) Immediately after step 6, take a photo of the hair sample and determine the area of the hair sample (expressed as the number of pixels) using the open - source, public software Image J. The results are shown in "Area (T0)" in Table 1.

[0246] 9) Wash the hair sample again with the SLS shampoo composition shown in Table 2, rinse thoroughly with tap water, and dry with a hair dryer (for about 90 seconds until dry).

[0247] 10) Evaluate the straightening degree and area (T1sh) of the hair sample again as described above. The results are shown in "Straightening effect (T1sh)" and "Area (T1sh)" in Table 1.

[0248] The evaluation results in Table 1 show that, compared to using glyoxylic acid alone, the combined use of glyoxylic acid and betaine compounds can further maintain the straightened shape of the hair or reduce the increase in hair volume (which reflects the de - straightening or curling of the hair).

[0249] Of particular note is that glyoxylic acid can straighten the hair, and the combined use of betaine compounds with glyoxylic acid can prevent or reduce the de - straightening or curling of the hair. In other words, betaine compounds can help to further maintain the straightened shape of the hair provided by glyoxylic acid and prevent the hair from curling or returning to its original shape (if its original shape is curly).

[0250] Example 7 and Comparative Example 6

[0251] [Preparation]

[0252] Prepare each composition according to Example 7 and Comparative Example 6 by mixing the ingredients shown in Table 3. The numerical values of the amounts of the ingredients are all based on "wt%" of the raw materials.

[0253] Table 3

[0254]

[0255]

[0256] [Evaluation]

[0257] The above - mentioned compositions are used to straighten hair samples, and then the hair samples are evaluated according to the following protocol.

[0258] 1) Wash a hair sample of 27 - centimeter - long Chinese black, natural, slightly curly hair with the SLS shampoo composition shown in Table 2 above. Rinse the hair sample thoroughly with tap water.

[0259] 2) Apply 1 g of each composition according to Example 7 and Comparative Example 6 to the wet hair sample.

[0260] 3) Let the hair sample stay at room temperature (25 °C) for 10 minutes.

[0261] 4) Rinse the hair sample thoroughly with tap water.

[0262] 5) Dry the hair sample with a hair dryer (Nobby NB3100, TESCOM DENKI Co., Ltd, Japan) for about 90 seconds until dry.

[0263] 6) Straighten the hair sample with hair straighteners (ADST Premium DS2, Hakko Limited, Japan) at 180 °C for 3 passes, 4 seconds per pass.

[0264] 7) Immediately after step 6, visually evaluate the degree of straightening of the hair sample (straightening effect at T0) according to the following criteria.

[0265] 5: Very good

[0266] 4: Good

[0267] 3: Fair

[0268] 2: Poor

[0269] 1: Very poor

[0270] The results are shown in "Straightening effect (T0)" in Table 3.

[0271] 8) Immediately after step 6, take a photo of the hair sample and determine the area of the hair sample (expressed as the number of pixels) using open-source, public software Image J. The results are shown in "Area (T0)" in Table 3.

[0272] 9) Shampoo the hair sample again with the SLS shampoo composition shown in Table 2, rinse thoroughly with tap water, and dry with a hair dryer (for about 90 seconds until dry).

[0273] 10) Evaluate the degree of straightening and area (T1sh) of the hair sample again as described above. The results are shown in "Straightening effect (T1sh)" and "Area (T1sh)" in Table 3.

[0274] The evaluation results in Table 3 also show that, compared to using only glyoxylic acid, the combination of glyoxylic acid and betaine compounds can further maintain the straightened shape of the hair or reduce the increase in hair volume (which reflects the de-straightening or curling of the hair).

[0275] Therefore, it is clear that the present invention can not only act in a relatively simple aqueous solution (Examples 1-6), but also act in an emulsion-type formulation (Example 7) similar to a commercial hair conditioner.

Claims

1. A method for straightening keratin fibers such as hair, comprising the steps of: (i) applying a composition to the keratin fibers; (ii) optionally rinsing the keratin fibers and drying or not drying the keratin fibers after rinsing; and (iii) straightening the keratin fibers at a temperature above 50°C, preferably above 100°C and more preferably above 150°C, wherein the composition comprises (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxylamides, and mixtures thereof; (b) at least one betaine compound; and (c) water.

2. The method according to claim 1, wherein the composition is applied to wet keratin fibers.

3. The method according to claim 1 or 2, wherein the pH of the composition is 7 or lower, preferably 6 or lower, and more preferably 5 or lower.

4. The method according to any one of claims 1 to 3, wherein the amount of (a) one or more compounds in the composition is 0.1% to 50% by weight, preferably 0.5% to 40% by weight, and more preferably 1% to 30% by weight based on the total weight of the composition.

5. The method according to any one of claims 1 to 4, wherein (b) the betaine compound is selected from trimethylglycine, carnitine, and L-proline betaine or stachydrine, and mixtures thereof.

6. The method according to any one of claims 1 to 5, wherein the amount of (b) one or more betaine compounds in the composition is 0.01% to 15% by weight, preferably 0.05% to 10% by weight, and more preferably 0.1% to 5% by weight based on the total weight of the composition.

7. The method according to any one of claims 1 to 6, wherein the amount of (c) water in the composition is 20% to 99% by weight, preferably 30% to 95% by weight, and more preferably 40% to 90% by weight based on the total weight of the composition.

8. The method according to any one of claims 1 to 7, wherein the composition further comprises (d) at least one compound different from the (a) compound, selected from keto acids, their salts, and mixtures thereof.

9. The method according to claim 8, wherein the (d) compound is selected from levulinic acid, its salts, and mixtures thereof.

10. The method according to claim 8 or 9, wherein the amount of the (d) compound in the composition is 0.1% to 15% by weight, preferably 0.5% to 10% by weight, and more preferably 1% to 5% by weight based on the total weight of the composition.

11. The method according to any one of claims 1 to 10, wherein the composition does not contain any ammonia or thiol compounds, or contains less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of ammonia or thiol compounds based on the total weight of the composition.

12. The method according to any one of claims 1 to 11, wherein the composition does not contain any reducing agent or oxidizing agent, or contains a reducing agent or oxidizing agent in an amount of less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight, based on the total weight of the composition.

13. A composition for straightening keratin fibers such as hair by heating, comprising: (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxamides, and mixtures thereof; (b) at least one betaine compound; and (c) water.

14. A kit for straightening keratin fibers such as hair, comprising: at least one heater, preferably a heated iron, capable of providing a temperature to the keratin fibers that is higher than 50 °C, preferably higher than 100 °C, and more preferably higher than 150 °C; and at least one composition comprising (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxamides, and mixtures thereof; (b) at least one betaine compound; and (c) water.

15. (b) Use of at least one betaine compound in a composition for straightening keratin fibers such as hair by heating, the composition comprising: (a) at least one compound selected from glyoxylic acid, glyoxylic acid solvates, glyoxylates, glyoxylates, glyoxamides, and mixtures thereof; and (c) water for prolonging the straightening effect of the composition on keratin fibers, in particular for further maintaining the straightened shape of the keratin fibers or preventing or reducing the curling of the keratin fibers.

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