A process for treating keratin fibers employing a composition comprising at least two distinct specific alkane-diols, the composition having a low water content

Abstract

The present invention relates to a process for treating keratin fibers using a composition comprising at least two distinct particular alkane-diols, the composition having a low water content.

Description

Title of the invention: A process for treating keratin fibers using a composition comprising at least two distinct specific alkane-diols, the composition having a low water content. Technical field of the invention

[0001] The present invention relates to a process for treating keratin fibers using a composition comprising at least two distinct particular alkane-diols, the composition having a low water content. Context of the invention

[0002] Many people are not satisfied with the appearance of their hair, especially people with curly hair who most often seek to obtain straight hair and, conversely, those with straight hair wish to have curly hair.

[0003] To remedy this problem, it is possible to permanently modify the shape of hair using a process comprising a reduction step employing one or more reducing agents chosen particularly from among sulfites, bisulfites, alkylphosphines, or preferably thiols, and a so-called fixing step employing one or more oxidizing agents, particularly hydrogen peroxide. However, this type of process can, in the long term, lead to an alteration in hair quality resulting in a decrease in its cosmetic properties, such as its vitality and shine, and / or a degradation of its mechanical properties, particularly when the treated hair is already weakened, for example, colored or bleached hair. Furthermore, odor problems are very common with both the reducing compositions used, especially those containing thiols, and with the reduced hair.

[0004] It is also possible to permanently modify the shape of hair using a single-step process called lanthionization, which employs a composition comprising a base belonging to the hydroxide family. This type of process irreversibly replaces disulfide bonds (-CH2-SS-CH2-) with lanthionein bonds (-CH2-S-CH2-). This technique is primarily used for styling naturally curly hair. However, the hydroxides used in this process have the major drawback of being caustic. This causticity can, in some cases, affect the scalp. sometimes causing irritation and also affecting the condition of the hair, making it, on the one hand, rough to the touch and, on the other hand, much more fragile.

[0005] These classic techniques of permanent deformation of keratin fibers do not meet the needs of people wishing to temporarily change the shape of their hair, without risk of weakening it.

[0006] It is possible to temporarily deform hair by saturating it with water. However, the curl-relaxing or straightening effect observed is not lasting, and the curly hair treated in this way returns to its initial state. To improve the durability of the curl-relaxing or straightening effect, humectants such as glycerol can be used. However, the concentration of glycerol that can be used in hair formulations remains very limited due to the sticky effect it can produce. Indeed, the higher the glycerol concentration, the stickier, tackier, and / or more difficult the hair can be to style.

[0007] There is therefore a real need to develop a process for treating keratin fibers that leads to a temporary deformation of the keratin fibers, in order to smooth them and, when the hair is curly, to obtain better curl relaxation and / or better curl definition. The effect obtained must, in particular, be more durable and still observable for at least 6 hours, or even at least 24 or 48 hours after application of the process, without compromising the cosmetic properties, particularly regarding the stickiness of the compositions used in the process.

[0008] Such a process must also make it possible to preserve the quality and integrity of the treated fibers, making it possible to repeat the process, including on damaged and / or sensitized keratin fibers.

[0009] Furthermore, such a process must also employ less malodorous compositions, particularly without reducing agents such as thiols. Finally, the formulation of environmentally friendly cosmetic products—that is, products whose design and development take environmental issues into account—is becoming a major concern in order to contribute to meeting global challenges. It is therefore essential to offer more sustainable cosmetic processing methods that address these environmental issues, notably by reducing the use of petrochemical-based compounds such as silicone raw materials.

[0010] The applicant has surprisingly discovered that all or part of these objectives can be achieved by the process according to the present invention. Summary of the invention

[0011] According to a first aspect, the present invention relates to a method for treating keratin fibers comprising a) applying to the keratin fibers a composition (C) comprising: (i) at least 5% by weight, relative to the total weight of composition (C), of at least two distinct compounds A selected from the (C2-C6)alkane-diols; ii) less than 5% by weight, relative to the total weight of the composition (C), of water.

[0012] According to a second aspect, the present invention relates to the composition (C) as defined above.

[0013] According to a third aspect, the present invention relates to the use of composition (C) as defined above, for the relaxation of curls and / or the smoothing of keratin fibers. Detailed description of the invention

[0014] For the purposes of the present invention, and unless otherwise indicated:

[0015] ■ By "keratin fibers" we mean fibers of human or animal origin such as such as hair, body hair, eyelashes, eyebrows, wool, angora, cashmere, or fur. According to the present invention, the keratin fibers are preferably human keratin fibers, more preferably hair.

[0016] ■ by "butylene glycol" means butane-1,3-diol.

[0017] The expressions "at least one" and "one or more" are synonymous and can be used interchangeably.

[0018] The expressions "between ... and ...", "includes from ... to ...", "made up of ... to ...", and "ranging from ... to ..." should be understood inclusive of bounds, unless otherwise specified. Keratin fiber processing method

[0019] According to a first aspect, the present invention relates to a process for treating keratin fibers as defined above.

[0020] The process according to the present invention is preferably a process for relaxing loops and / or smoothing keratin fibers.

[0021] The applicant found, surprisingly, that the process according to the invention made it possible to obtain a good quality smoothing of the keratin fibers and when the hair is curly, a better relaxation of the curls and / or a better definition of them, the effect observed being more durable over time, in particular always observable for at least 6 hours, or even at least 24 or 48 hours after implementation of the process, without compromise with regard to the cosmeticity of the composition implemented in the process according to the invention with in particular a less sticky and less tacky feel. Composition (C)

[0022] Composition (C) comprises: (i) at least 5% by weight, relative to the total weight of composition (C), of at least two distinct compounds A selected from the (C2-C6)alkane-diols; (ii) less than 5% by weight, relative to the total weight of composition (C), of water. Separate compounds A

[0023] Composition (C) comprises i) at least 5% by weight, relative to the total weight of composition (C), of at least two distinct compounds A selected from the (C2-C6)alkane-diols.

[0024] Preferably, the distinct compounds A are chosen from the compounds of the following formula (I): HO-R-OH (I) Formula (I) in which R represents a divalent hydrocarbon radical, linear or branched, comprising from 2 to 6 carbon atoms.

[0025] According to a particular embodiment, the distinct compounds A are selected from compounds of formula (I) as defined above, in which R represents a linear divalent hydrocarbon radical comprising from 2 to 6 carbon atoms. According to this particular embodiment, the distinct compounds A are preferably selected from propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, ethylene glycol, their optical isomers, and mixtures thereof.

[0026] According to a particular embodiment, the distinct compounds A are selected from the compounds of formula (I) as defined above, in which R represents a divalent hydrocarbon radical, linear or branched, comprising from 3 to 5 carbon atoms. According to this particular embodiment, the distinct compounds A are preferably selected from butylene glycol, propane-1,3-diol, butane-1,4-diol, 2-methyl-1,3-propanediol, pentane-1,5-diol, butane-1,2-diol, their optical isomers, and mixtures thereof.

[0027] More preferably, the distinct compounds A are selected from butylene glycol, propane-1,3-diol, butane-1,4-diol, 2-methyl-1,3-propanediol, pentane-1,5-diol, hexane-1,6-diol, butane-1,2-diol, ethylene glycol, their optical isomers, and mixtures thereof,

[0028] Even more preferably, the distinct compounds A are selected from butylene glycol, propane-1,3-diol, pentane-1,5-diol, butane-1,2-diol, their optical isomers, and mixtures thereof.

[0029] In the most preferred manner, the distinct compounds A are chosen from: - mixtures of butylene glycol and propane-1,3-diol, the mass ratio of total quantity of butylene glycol / total quantity of propane-1,3-diol in composition (C) preferably ranging from 2 / 3 to 3 / 2 such that 1 / 1; - mixtures of butylene glycol and pentane-l,5-diol, the mass ratio of total quantity of butylene glycol / total quantity of pentane-l,5-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1; - mixtures of butylene glycol and butane-1,2-diol, the mass ratio of total quantity of butylene glycol / total quantity of butane-1,2-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1; or - mixtures of pentane-1,5-diol and propane-1,3-diol, preferably having a mass ratio of total quantity of pentane-1,5-diol / total quantity of propane-1,3-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1.

[0030] Better still, the distinct compounds A are chosen from mixtures of butylene glycol and propane-1,3-diol, the mass ratio of total quantity of butylene glycol / total quantity of propane-1,3-diol in composition (C) preferably ranging from 2 / 3 to 3 / 2 such as 1 / 1.

[0031] Preferably, composition (C) does not comprise more than two distinct compounds A selected from the (C2-C6)alkane-diols.

[0032] Preferably, the composition (C) comprises a total content of distinct compounds A selected from the (C2-C6)alkane-diols, of at least 10% by weight, preferably from 10% to 100% by weight, more preferably from 40% to 100% by weight, relative to the total weight of the composition (C).

[0033] More preferably, the composition (C) comprises a total content of distinct compounds A selected from butylene glycol, propane-1,3-diol, butane-1,4-diol, 2-methyl-1,3-propanediol, pentane-1,5-diol, hexane-1,6-diol, butane-1,2-diol, ethylene glycol, their optical isomers, and mixtures thereof, of at least 5% by weight, preferably at least 10% by weight, more preferably from 10% to 100% by weight, even more preferably from 40% to 100% by weight, relative to the total weight of the composition (C).

[0034] Even more preferably, the composition (C) comprises a total content of distinct compounds A selected from butylene glycol, propane-1,3-diol, pentane-1,5-diol, butane-1,2-diol, their optical isomers, and mixtures thereof, of at least 5% by weight, preferably at least 10% by weight, more preferably from 10% to 100% by weight, even more preferably from 40% to 100% by weight, relative to the total weight of the composition (C).

[0035] Most preferably, composition (C) comprises a total content of distinct compounds A selected from mixtures of butylene glycol and propane-1,3-diol of at least 5% by weight, preferably at least 10% by weight, more preferably from 10% to 100% by weight, even more preferably from 40% to 100% by weight, relative to the total weight of composition (C). Water

[0036] Composition (C) further comprises ii) less than 5% by weight, relative to the total weight of composition (C), of water.

[0037] Preferably, composition (C) comprises a total water content of less than 1% by weight, preferably less than 0.1% by weight, more preferably less than 0.01% by weight, relative to the total weight of composition (C), and even better composition (C) is anhydrous.

[0038] Where applicable, such small quantities of water may be introduced, in particular, by ingredients in the composition that may contain residual amounts. Compounds B

[0039] Composition (C) may further comprise iii) one or more compounds B selected from (C3-C6)alkane-triols, preferably selected from glycerol, butane triols, pentane triols, hexane triols, their optical isomers, and mixtures thereof.

[0040] Preferably, compound(s) B are chosen from the compounds of the following formula (II): R-(OH)3 (II) Formula (II) in which R represents a trivalent hydrocarbon radical, linear or branched, comprising from 3 to 6 carbon atoms.

[0041] More preferably, the compound(s) B are selected from glycerol, 1,2,4-Butanetriol, 2-Hydroxymethyl-1,3-propanediol, 1,1,1 Tris(hydroxymethyl)ethane, 1,2,6-Hexanetriol, 1,1,1 Tris(hydroxymethyl)propane, their optical isomers, and mixtures thereof.

[0042] Even more preferably, compound B is glycerol.

[0043] Preferably, composition (C) comprises a total content of compounds B selected from the (C3-C6)alkane-triols, of at least 1% by weight, preferably of at least 5% by weight, more preferably ranging from 10% to 60% by weight, even more preferably ranging from 10% to 55% by weight, relative to the total weight of composition (C).

[0044] More preferably, the composition (C) comprises a total glycerol content of at least 1% by weight, preferably at least 5% by weight, more preferably from 10% to 60% by weight, even more preferably from 10% to 55% by weight, relative to the total weight of the composition (C). Other characteristics of the composition (C)

[0045] Composition (C) is preferably liquid, possibly thickened.

[0046] By "liquid composition" in the context of the present invention, we mean, on a macroscopic scale, a product that does not have a fixed shape and cannot be grasped, unlike a solid. It is a fluid that adapts to the shape of the container. in which it is placed at room temperature (25°C). When transferred to another container, a liquid still retains its volume. A liquid therefore has a fixed volume. At rest, the free surface of a liquid is generally flat and horizontal.

[0047] By "thickened composition" in the context of the present invention is meant a liquid composition with a viscosity greater than 900 mPa.s at 25°C, or even a gel.

[0048] Preferably, composition (C) comprises a total ethanol content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight, relative to the total weight of composition (C), and even better, composition (C) is free of ethanol.

[0049] Preferably, composition (C) comprises a total isopropanol content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight, relative to the total weight of composition (C), and even better, composition (C) is free of isopropanol.

[0050] Preferably, composition (C) comprises a total content of Ci-C6 monoalcohols of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight, relative to the total weight of composition (C), and even better, composition (C) is free of Ci-C6 monoalcohols.

[0051] By "Ci-C6 monoalcohol", we mean a compound comprising only one hydroxyl group (-OH) of formula R-OH in which R represents a saturated Ci-C6 hydrocarbon chain, linear or branched, the hydroxyl group (-OH) being able to be borne by a primary, secondary or tertiary carbon atom.

[0052] Preferably, composition (C) comprises a total silicone content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better less than 0.001% by weight relative to the total weight of composition (C).

[0053] By "silicone" is meant all organosilicon polymers or oligomers with a linear or cyclic, branched or cross-linked structure, of variable molecular weight, obtained by polymerization and / or polycondensation of suitably functionalized silanes, and consisting essentially of a repetition of principal motifs in which the silicon atoms are linked together by oxygen atoms (siloxane bond -Si-O-Si-), with hydrocarbon radicals possibly substituted, being directly linked via a carbon atom to said silicon atoms.

[0054] Preferably, composition (C) comprises a total cationic polymer content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better less than 0.001% by weight, relative to the total weight of composition (C), and even better composition (C) is free of cationic polymers.

[0055] By "cationic polymer" is meant any non-siliconized polymer (not comprising silicon atoms) containing cationic groups and / or groups ionizable into cationic groups, and not containing anionic groups and / or groups ionizable into anionic groups.

[0056] Preferably, composition (C) comprises a total cationic surfactant content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight relative to the total weight of composition (C), and even better composition (C) is free of cationic surfactants.

[0057] Preferably, composition (C) comprises a total content of poly(oxyethylenated) compounds of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight relative to the total weight of composition (C), and even better composition (C) is free of poly(oxyethylenated) compounds.

[0058] The composition (C) may further comprise at least one cosmetic ingredient selected from non-ionic, anionic, amphoteric surfactants, vitamins and pro-vitamins other than vitamin B1 including panthenol, fillers, colouring materials, pearlescent agents, opacifying agents, sequestering agents, film-forming polymers, anionic or neutral, associative polymers, plasticizing agents, oils, antifoaming agents, moisturizing agents, emollients, penetration agents, perfumes, preservatives, and mixtures thereof.

[0059] The composition (C) may further include at least one cosmetic ingredient selected from sequestering agents, oils, moisturizing agents, emollients, penetration agents, perfumes, preservatives, and mixtures thereof.

[0060] These common cosmetic ingredients may be present in the composition in typical quantities, easily determinable by those skilled in the art, and which may range, for each ingredient, from 0.01% to 20% by weight relative to the total weight of the composition. Those skilled in the art shall ensure that the ingredients included in the composition, as well as their quantities, are chosen in such a way that they do not impair the properties of the composition.

[0061] Composition (C) is a cosmetic composition, i.e. which includes a cosmetically acceptable medium, that is to say, a medium compatible with human keratin fibers.

[0062] Preferably, composition (C) comprises a total content of colouring agents of less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight, relative to the total weight of composition (C).

[0063] Even more preferably, composition (C) is free of coloring agents.

[0064] By "coloring agent" is meant an oxidation dye, a direct dye or a pigment.

[0065] The term "oxidation dye" refers to an oxidation dye precursor selected from oxidation bases and couplers. Oxidation bases and couplers are compounds that are slightly colored or colorless and which, through a condensation reaction in the presence of an oxidizing agent, give a colored species.

[0066] By "direct dye" is meant a natural and / or synthetic dye, including in the form of extract(s), distinct from oxidation dyes. These are colored compounds that diffuse superficially onto the fiber. They can be ionic or non-ionic, i.e., anionic, cationic, neutral, or non-ionic.

[0067] The composition (C) can thus be in any form compatible with application to keratin fibers, for example in the form of wax, paste, cream more or less fluid or thick, gel, foam, spray, lotion.

[0068] Additional features concerning the process

[0069] Composition (C) can be applied to dry or wet keratin fibers, preferably dry.

[0070] The process according to the invention can be implemented on natural keratin fibers, in particular natural hair.

[0071] The process according to the invention can also be implemented on damaged and / or sensitized keratin fibers, in particular damaged and / or sensitized hair.

[0072] By "damaged keratin fibers" we mean dry, rough, brittle, split and / or soft keratin fibers.

[0073] By "sensitized keratin fibers" is meant bleached, artificially colored, straightened and / or permed keratin fibers.

[0074] The process according to the invention can advantageously be implemented on curly, frizzy or kinky keratin fibers, in particular curly, frizzy or kinky hair.

[0075] The bath ratio of the composition (C) applied to the keratin fibers can range from 0.01 to 10. By bath ratio, we mean the ratio between the total weight of the composition (C) applied and the total weight of keratin fibers to be treated.

[0076] The process according to the invention may include at least one additional step a') of washing the keratin fibers, preferably prior to step a) and / or at least one additional step following step a) chosen from the following steps b) and / or c): b) a step of applying the composition (C) to the keratin fibers, preferably lasting at least 10 seconds, said application step possibly being carried out under an airtight film such as a papillote or plastic film; c) a drying step of the keratin fibers in ambient air or with the aid of a heating device, preferably in ambient air.

[0077] Preferably, the process includes step a') as described above and additional steps b) and c) as described above and carried out in that order.

[0078] The washing step a') can for example be carried out using shampoo.

[0079] The temperature of the heating device can range from 45°C to 230°C, preferably from 45°C to 100°C, more preferably from 50°C to 80°C. A hair dryer, a heated helmet, an iron, or a heated brush can be used as a heating device, for example. Composition (C)

[0080] According to a second aspect, the present invention relates to the composition (C) as defined above. Use

[0081] According to a third aspect, the present invention relates to the use of composition (C) as defined above, for the relaxation of curls and / or the smoothing of keratin fibers. Examples

[0082] The following examples serve to illustrate the invention without, however, being limiting. In the examples that follow, unless otherwise indicated, when compositions are used, the contents are given as mass percentages relative to the total weight of the composition in question.

[0083] The following Cl to C5 and DI to D5 compositions were prepared and tested according to the procedure described below. Compositions Cl to C5

[0084] [Tables 1] Ingredients C1 (Comparative) C2 (Comparative) C3 (Comparative) C4 (Comparative) C5 (Comparative) Butylene glycol 100 - - - - Pentane-1,5-diol - 100 - - - Butane-1,2-diol - - 100 - - Propane-1,3-diol - - - 100 - Glycerol - - - - 100 Compositions DI to D4

[0085] [Tables2] Ingredients DI (Invention) D2 (Invention) D3 (Invention) D4 (Invention) D5 (Invention) Butylene glycol 50 50 42 - 34 Pentane-1,5-diol 50 - - 50 - Butane-1,2-diol - 50 - - - Propane-1,3-diol - - 43 50 33 Glycerol - - 15 - 33 Operating procedure

[0086] Strands of 2.7 g of natural hair, type 2C according to the André Walker classification, were used. The strands were washed with two successive DOP shampoos (0.4 g / g of hair), then towel-dried and finally left to air dry before application of the compositions to be tested. 0.15g of each of the compositions Cl to C5 and DI to D5 to be tested were then applied to dry strands. This application was done with the fingers while massaging the hair fiber. The hair strands were then suspended at ambient temperature and humidity set at 22°C and 45% relative humidity. For each strand treated with compositions Cl to C5 and DI to D5, the percentage of elongation was calculated 6 or 48 hours after application to evaluate the treatment's effectiveness.

[0087] The percentage of elongation of the wick 6h or 48h after application is calculated according to the following formula: in which L represents the length of the strand 6h or 48h after application and Lo represents the length of the initial strand before application of the composition to be tested. Results:

[0088] Percentage of strand elongation 6 hours after application

[0089] [Tables3] Treatment Type Percentage of Elongation 6h Post Application Cl (Comparative) 4.69 C2 (Comparative) 2.78 C4 (Comparative) 1.96 C5 (Comparative) 0.51 D3 (Invention) 6.24 D4 (Invention) 6.47

[0090] The strand treated with composition D3 or D4 according to the invention exhibits a higher percentage of elongation 6 hours after application than the strands treated with the comparative compositions C1, C2, C4, or C5. The process according to the present invention therefore makes it possible to obtain good quality straightening with better curl relaxation 6 hours after application of composition D3 or D4. Furthermore, The sticky appearance of hair strands treated with composition D3 or D4 is not a deal-breaker.

[0091] Percentage of strand elongation 48 h after application

[0092] [Tables4] Treatment Type Percentage of Elongation 48 h after Application Cl (Comparative) 0.82 C2 (Comparative) 0.52 C3 (Comparative) -0.75 C4 (Comparative) -2.53 C5 (Comparative) -1.44 DI (Invention) 2.48 D2 (Invention) 1.95 D3 (Invention) 5.13 D4 (Invention) 2.13 D5 (Invention) 3.84

[0093] Strands treated with compositions DI to D5 according to the invention exhibit a higher percentage of elongation 48 hours after application than strands treated with comparative compositions C1 to C5. The process according to the present invention therefore makes it possible to obtain good quality straightening with better curl relaxation 48 hours after application of compositions DI to D5. Furthermore, the sticky appearance of hair strands treated with compositions DI to D5 according to the invention is not a drawback.

Claims

Demands

1. A process for treating keratin fibers comprising a) applying to the keratin fibers a composition (C) comprising: i) at least 5% by weight, relative to the total weight of the composition (C), of at least two distinct compounds A selected from the (C2-C6)alkane-diols; ii) less than 5% by weight, relative to the total weight of the composition (C), of water.

2. A method according to any one of the preceding claims, wherein the composition (C) comprises a total content of distinct compounds A of at least 10% by weight, preferably from 10% to 100% by weight, more preferably from 40% to 100% by weight, relative to the total weight of the composition (C).

3. A method according to the preceding claim, wherein the distinct compounds A are selected from the compounds of the following formula (I): HO-R-OH (I) Formula (I) in which R represents a divalent hydrocarbon radical, linear or branched, comprising from 2 to 6 carbon atoms; preferably from butylene glycol, propane-1,3-diol, butane-1,4-diol, 2-methyl-1,3-propanediol, pentane-1,5-diol, hexane-1,6-diol, butane-1,2-diol, ethylene glycol, their optical isomers, and mixtures thereof, more preferably from butylene glycol, propane-1,3-diol, pentane-1,5-diol, butane-1,2-diol, their optical isomers, and mixtures thereof; even more preferentially among: - mixtures of butylene glycol and propane-1,3-diol, the mass ratio of total quantity of butylene glycol / total quantity of propane-1,3-diol in composition (C) preferably ranging from 2 / 3 to 3 / 2 such that 1 / 1;- mixtures of butylene glycol and pentane-1,5-diol, the mass ratio of total quantity of butylene glycol / total quantity of pentane-1,5-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1; - mixtures of butylene glycol and butane-1,2-diol, the mass ratio of total quantity of butylene glycol / total quantity of butane-1,2-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1; or; - mixtures of pentane-1,5-diol and propane-1,3-diol, preferably having a mass ratio of total quantity of pentane-1,5-diol / total quantity of propane-1,3-diol ranging from 2 / 3 to 3 / 2 such that 1 / 1; and preferably among mixtures of butylene glycol and propane-1,3-diol, the mass ratio of total quantity of butylene glycol / total quantity of propane-1,3-diol in composition (C) preferably ranging from 2 / 3 to 3 / 2 such that 1 / 1.

4. A method according to the preceding claim, wherein the composition (C) does not comprise more than two distinct compounds A.

5. A method according to any one of the preceding claims, wherein the composition (C) further comprises iii) one or more compounds B selected from the (C3-C6)alkane-triols, preferably selected from glycerol, butane triols, pentane triols, hexane triols, their optical isomers, and mixtures thereof; more preferably selected from compounds of the following formula (II): R-(OH)3 (II) Formula (II) wherein R represents a trivalent hydrocarbon radical, linear or branched, comprising from 3 to 6 carbon atoms; even more preferentially chosen from glycerol, 1,2,4-Butanetriol, 2-Hydroxymethyl-1,3-propanediol, 1,1,1 Tris(hydroxymethyl)ethane, 1,2,6-Hexanetriol, 1,1,1 Tris(hydroxymethyl)propane, their optical isomers, and their mixtures, and better glycerol.

6. A method according to the preceding claim, wherein the composition (C) comprises a total content of compounds B of at least 1% by weight, preferably of at least 5% by weight, more preferably from 10% to 60% by weight, even more preferably from 10% to 55% by weight, relative to the total weight of the composition (C).

7. A method according to any one of the preceding claims, wherein the composition (C) comprises a total water content of less than 1% by weight, preferably less than 0.1% by weight, more preferably less than 0.01% by weight, relative to the total weight of the composition (C) and even better the composition (C) is anhydrous.

8. A method according to any one of the preceding claims, wherein the composition (C) is liquid, optionally thickened.

9. A method according to any one of the preceding claims, wherein the composition (C) comprises a total ethanol content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight, relative to the total weight of the composition (C), and even better, the composition (C) is free of ethanol.

10. A method according to any one of the preceding claims, wherein the composition (C) comprises a total isopropanol content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better still less than 0.001% by weight, relative to the total weight of the composition (C), and even better, the composition (C) is isopropanol-free.

11. A method according to any one of the preceding claims, wherein the composition (C) comprises a total silicone content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better yet less than 0.001% by weight, relative to the total weight of the composition (C).

12. A method according to any one of the preceding claims, wherein the composition (C) comprises a total cationic polymer content of less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight, most preferably less than 0.01% by weight, and better less than 0.001% by weight, relative to the total weight of the composition (C), and even better the composition (C) is free of cationic polymers.

13. A method according to any one of the preceding claims, wherein the keratin fibers are curly, crimped, or frizzy keratin fibers.

14. A method according to any one of the preceding claims, wherein the method comprises at least one additional step a') of washing the keratin fibers, preferably prior to step a) and /

15.

16.

17. or at least one additional step following step a) chosen from the following steps b) and / or c): b) a step of applying the composition (C) to the keratin fibers, preferably lasting at least 10 seconds, said application step possibly being carried out under an airtight film such as a papillote or plastic film; (c) a step of drying the keratin fibers in ambient air or with the aid of a heating device, preferably in ambient air. A process according to any one of the preceding claims, wherein the process is a process for relaxing loops and / or smoothing keratin fibers. Composition (C) as defined in any one of claims 1 to 12. Use of composition (C) as defined in any one of claims 1 to 12, for the relaxation of loops and / or the smoothing of keratin fibers.