FR2939611A1 - Keratin fiber i.e. hair, permanent deformation method, involves installing rigid covering unit for covering mechanical powering unit to form closed space to maintain temperature between specific range - Google Patents

Abstract

The method involves mechanical powering keratinous fibers by winding the keratinous fibers on a mechanical powering unit to form loops, and applying an acid reducing composition on the keratinous fibers. The keratinous fibers are rinsed. A rigid covering unit is installed for covering the mechanical powering unit to form a closed space to maintain temperature between 50 and 250 degrees Centigrade, where the covering unit is utilized as a heating unit. The mechanical powering unit is selected from a group consisting of a hair-curler, a roller and a grip.

Description

The present invention relates to a method of permanently deforming the hair comprising, inter alia, a step of heating the hair using a heating mechanical tensioning device. The invention also relates to the heating mechanical tensioning device. The most usual technique for obtaining a permanent deformation of the hair consists, in a first step, in opening the disulfide -SS- bonds of keratin (keratocystin) using a composition containing a suitable reducing agent ( reduction step) then, after having rinsed the hair thus treated, generally with water, to reconstitute in a second time said disulfide bonds by applying to the hair previously tensioned for example by curlers, an oxidizing composition (step d oxidation, also called fixation) so as finally to give the hair the desired shape. This technique thus makes it possible to perform the waving of the hair (permanent process). The new form imposed on the hair by a chemical treatment as above is eminently durable over time and resists particularly the action of washing with water or shampoo, and this as opposed to simple conventional techniques of temporary deformation, such as styling. It is constantly sought more effective permanent deformation processes, less harmful to keratin fibers and leading to more durable capillary deformations. In order to improve the performance of permanent processes, the compositions generally used contain significant concentrations of reducing agent (s). For the same purpose, it has also been developed a heating process during the reduction step, in order to increase the chemical action of the reducing agent or agents. These technologies use hot air, hot steam or infrared to heat hair on a roller or hair curler.

It has been observed that these technologies do not lead to a significant improvement in terms of longevity of the capillary deformation, such as, for example, loops, compared with conventional cold-perm techniques. In addition, the treated hair has significant degradations, which inhibit users to perform repeated hair treatments, such as permanent perms or the combination of a permanent and a color for example. EP 1 935 275 discloses a method of deforming the hair by means of flexible hair curlers and reclosable on themselves. In Example 2 of this document, there is described a method in which a reducing composition is applied to flexible curlers and a plastic film is wrapped around the head. Helmet heating is carried out for 15 minutes until the hair has completely dried. An oxidizing composition is then applied. We pause for 5 minutes and remove the hair curlers. However, this method can be further improved, since the shape and the nervousness of the crimps are still insufficient. There is therefore a need to find a method of tensioning the hair, giving loops of shape and improved nervousness. Thus, the invention relates to a method of particular deformation of the hair,

step of mechanically tensioning the keratinous fibers by winding them on mechanical tensioning means so as to form loops, then b) a step of applying to the keratinous fibers of an acid reducing composition, then C) a possible step of rinsing said fibers, then d) a step of placing a cover means of said mechanical tensioning means to form a closed space for maintaining a temperature between 50 and 250 ° C then e) a step of heating said fibers, then f) a possible oxidation fixation step after removal of the permanent cover means from the keratinous fibers, comprising: a) a characterized in that at least one said mechanical tensioning means and said covering means include heating means. According to the invention, the term "acid composition" means a composition whose pH is between 1 and 7, the terminals 1 and 7 being included. Closed space means that when the covering means is put in place on the mechanical tensioning means, they together constitute a closed structure in which the heat can diffuse. According to a variant of the invention, the closed space may comprise opening zones, the surface area of which is less than 5% of the total area of the covering means, preferably less than 3%, and more particularly less than 0%. , 5%. According to this variant, the total surface of the covering means comprises the surface of the opening means, and when present, the surface of the raising means. The openings may be passages, holes, or orifices, which may allow an exchange of air between the closed space and the outside, especially when the condensation inside the closed space is too great.

The invention finally relates to a kit. Other features, aspects, objects and advantages of the present invention will become more apparent upon reading the description which follows. The process of permanent deformation of keratinous fibers, in particular the hair, comprises a first step (a) of mechanically tensioning the keratinous fibers by winding them onto mechanical tensioning means so as to form loops. The winding of the mechanical tensioning devices can be done along the entire length of the hair or at mid-length on long hair. Depending on the shape of hairstyle and the amount of curls desired, the reeling is done with more or less thick locks. According to the method of the invention, the mechanical tensioning means may be a curler, a roller or a gripper.

Then follows a step of application to the keratinous fibers of a reducing composition (b), to reduce the disulfide bonds of keratin, followed by a possible exposure time. According to a variant of the process according to the invention, the step of application to the keratinous fibers of the reducing composition (noted b) can precede the step of mechanical stressing of the keratinous fibers (denoted by a), with or without pause time. In this case, the reduction step is carried out in the original form of the fibers, that is to say on non-energized fibers.

The reducing composition according to the invention has an acidic pH, that is to say between 1 and 7. The pH of the reducing composition according to the invention is preferably between 3 and 7, better still between 4 and 6, 5.

The reducing composition used in the process according to the invention generally comprises, in a cosmetically acceptable medium, a reducing agent chosen from thioglycolic acid and / or thiolactic acid and / or mercaptopropionic acid and / or monothioglycerol or cysteamine. and / or a salt thereof and / or an ester thereof.

The reducing agents used in the context of the process according to the invention are thioglycolic acid, of formula (1):

HS-CH 2 -COOH (1) thiolactic acid, of formula (2):

HS-CH-COOH (2) CH3

3-mercaptopropionic acid, of formula (3): HS-CH 2 -CH 2 -COOH (3) monothioglycerol, of formula (4):

HS-CH 2 -CHOH-CH 2 OH (4) The cysteamine of formula (5):

HS-CH2-CH2-NH2 (5) or a salt or an ester thereof. Among the cosmetically acceptable salts of the products (1) to (5) above, there may be mentioned more particularly the ammonium salts, the primary, secondary or tertiary amine salts, the alkaline earth metal salts. As primary, secondary or tertiary amine salts, mention may be made of monoethanolamine, di-isopropanolamine and triethanolamine, respectively.

Among the esters of the compounds (1) to (5) above, there may be mentioned glycerol monothioglycolate, ethylene glycol monothioglycolate, the azeotropic mixture of hydroxy-2-propyl thioglycolate and hydroxyl thioglycolate. 2-methyl-1-ethyl described in patent application FR-A-2 679 448, glycerol monothiolactate, ethylene glycol monothiolactate, glycerol 3-mercaptopropionate, ethylene glycol 3-mercaptopropionate.

These reducing agents are generally used in cosmetically acceptable compositions, which are also already well known per se in the state of the art existing curling formulations for performing the first step (reduction) of a permanent operation . Thus, as conventional and customary additives, which can be used alone or in mixtures, surfactants of nonionic, anionic, cationic or amphoteric type may be mentioned more particularly, and of these, mention may be made of alkyl sulphates and alkylbenzenesulfates. alkyl ether sulphates, alkyl sulphonates, quaternary ammonium salts, alkyl betaines, oxyethylenated alkylphenols, fatty acid alkanolamides, oxyethylenated fatty acid esters and other nonionic surfactants of the hydroxypropyl ether type.

When the reducing composition contains at least one surfactant, it is generally present at a maximum concentration of 30% by weight, and preferably between 0.5 and 10% by weight, relative to the total weight of the reducing composition. . The reducing agent or agents generally represent from 0.01 to 20%, preferably from 0.1 to 10% by weight relative to the total weight of the reducing composition.

In order to improve the cosmetic properties of the hair or to reduce or prevent its degradation, the reducing composition may also contain a treating agent of cationic, anionic, nonionic or amphoteric nature. Particularly preferred treating agents include those described in French Patent Application Nos. 2,598,613 and 2,470,596. It is also possible to use volatile or non-volatile, linear or cyclic silicones and mixtures thereof as treatment agents. polydimethylsiloxanes, quaternized polyorganosiloxanes such as those described in French Patent Application No. 2,535,730, polyorganosiloxanes containing aminoalkyl groups modified with alkoxycarbonylalkyl groups, such as those described in US Pat. No. 4,749,732, polyorganosiloxanes such as polydimethylsiloxane-polyoxyalkyl copolymer of the Dimethicone Copolyol type, a polydimethylsiloxane containing stearoxy (stearoxydimethicone) end groups, a polydimethylsiloxanedialkylammonium acetate copolymer or a polydimethylsiloxane polyalkylbetaine copolymer described in British Patent Application No. 2 197 352, organopolysiloxane polysiloxanes; modified by mercapto or mercaptoalkyl groups such as those described in French Patent No. 1,530,369 and in European Patent Application No. 295,780, as well as silanes such as stearoxytrimethylsilane.

The reducing composition may also contain other treating ingredients such as cationic polymers such as those used in the compositions of French Patent Nos. 79.32078 (FR-A-2 472 382) and 80.26421 (FR-A-2 495 931), or also cationic polymers of the ionene type such as those used in the compositions of the Luxembourg Patent No. 83703, basic amino acids (such as lysine, arginine) or acidic acids (such as glutamic acid, aspartic acid) , peptides and their derivatives, protein hydrolysates, waxes, swelling and penetration agents or to enhance the effectiveness of the reducing agent such as SiO 2 / PDMS (polydimethylsiloxane), dimethylisosorbitol, urea and its derivatives, pyrrolidone, N-alkyl-pyrrolidones, thiamorpholinone, alkylene glycol or dialkylene glycol alkyl ethers such as, for example, propylene glycol monomethyl ether, dipr monomethyl ether, opylene glycol, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether, C3-C6 alkanediols such as, for example, 1,2-propanediol and 1,2-butanediol, imidazolidinone-2 and other compounds such as fatty alcohols, lanolin derivatives, active ingredients such as pantothenic acid, anti-hair loss agents, anti-dandruff agents, thickeners, suspending agents, sequestering agents, opacifying agents, dyes, sunscreens as well as fragrances and preservatives.

The pH of the reducing composition according to the invention is preferably between 2 and 7, preferably between 4 and 6.5.

These pH can be obtained and / or adjusted conventionally by adding either basifying agents, such as for example ammonia, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, di-isopropanolamine, propanediamine-1,3 , an alkaline or ammonium carbonate or bicarbonate, an organic carbonate such as guanidine carbonate, or else an alkaline hydroxide, all these compounds can of course be taken alone or as a mixture, or acidifying agents such as for example hydrochloric acid, acetic acid, lactic acid or boric acid. In order to improve the cosmetic properties of the hair or to reduce or prevent its degradation, the reducing composition may also contain a treating agent of cationic, anionic, nonionic or amphoteric nature. Particularly preferred treating agents include those described in French Patent Application Nos. 2,598,613 and 2,470,596. Volatile or non-volatile silicones, linear or cyclic, and mixtures thereof, may also be used as treating agents. polydimethylsiloxanes, quaternized polyorganosiloxanes such as those described in French Patent Application No. 2,535,730, polyorganosiloxanes containing aminoalkyl groups modified with alkoxycarbonylalkyl groups such as those described in US Pat. No. 4,749,732, polyorganosiloxanes such as polydimethylsiloxane-polyoxyalkyl copolymer of the Dimethicone Copolyol type, a polydimethylsiloxane with stearoxy (stearoxydimethicone) end groups, a polydimethylsiloxane-dialkylammonium acetate copolymer or a polydimethylsiloxane polyalkylbetaine copolymer described in British Patent Application No. 2 197 352, organic polysiloxanes; difés by mercapto or mercaptoalkyl groups such as those described in French Patent No. 1,530,369 and in European Patent Application No. 295 780, as well as silanes such as stearoxytrimethylsilane. The reducing composition may also contain other treating ingredients such as cationic polymers such as those used in the compositions of French Patent Nos. 79.32078 (FR-A-2 472 382) and 80.26421 (FR-A-2 495 931), or also cationic polymers of the ionene type such as those used in the compositions of the Luxembourg Patent No. 83703. It may also contain basic amino acids (such as lysine, arginine) or acidic acids (such as glutamic acid, lysine). aspartic acid), peptides and their derivatives, protein hydrolysates, waxes, swelling and penetration agents or to enhance the effectiveness of the reducing agent such as SiO 2 / PDMS (polydimethylsiloxane), dimethylisosorbitol, urea and its derivatives, pyrrolidone, N-alkylpyrrolidones, solvents such as alkyl ethers of alkylene glycol or of dialkylene glycol such as for example monomethyl ether of propylene glycol, mono dipropylene glycol methyl ether, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether, C3-C6 alkanediols such as, for example, 1,2-propanediol and 1,2-butanediol, imidazolidinone-2 as well as other compounds such as fatty alcohols, lanolin derivatives, active ingredients such as pantothenic acid, anti-hair loss agents, anti-dandruff agents, thickeners, suspending agents, sequestering agents, opacifying agents, dyes , sunscreens as well as perfumes and preservatives. The reducing agent or agents generally represent from 0.01 to 20%, preferably from 0.1 to 10%, better still from 0.3% to 3% by weight relative to the total weight of the reducing composition. According to a preferred embodiment, the reducing composition is allowed to act for a period of 1 to 50 minutes, preferably for 1 to 30 minutes. Preferably, the reducing composition is applied to moist and clean capillary fibers. The process then optionally comprises a step of rinsing the keratinous fibers (c).

Preferably, the method according to the invention comprises a rinsing step (c). Then, the method according to the invention comprises a step (d) of setting up a cover means of said mechanical tensioning means to form a closed space intended to maintain a temperature of between 50 and 250 ° C. According to the method of the invention, the covering means may be a flexible or rigid material. The flexible material can be formed by a sheet, a film, a textile or a cap. For example, it may be a plastic film, especially polyvinylidene chloride or polyvinyl chloride, or aluminum foil. According to the method of the invention, the keratin fiber heating system limits the evaporation of the reducing composition and / or the rinsing water of said fibers and maintains the constant temperature of the hair throughout the heating step . According to the invention, the heating means may be included in the mechanical tensioning means (heating curlers directly covered with a film for example), included in the covering means, or included in these two means. Preferably, the heating means is included in the covering means. Then follows the heating step (e). The heating means may be a heating electric resistor powered by a battery or a mains plug. This resistance can be incorporated in the tensioning means (hair curlers for example) or in the covering means (plastic film for example, or it can be incorporated in these two means.

Preferably, the temperature is between 50 ° C and 250 ° C, more preferably between 60 ° C and 90 ° C. The duration of the heating is generally between 1 minutes and 2 hours, preferably between 1 and 30 minutes. Generally, the duration of heating is a function of the set temperature and the amount of wick wrapped around the device. The method according to the invention optionally comprises an oxidation fixation step (f), after removal of the covering means, for reforming the disulfide bonds, by application to the keratinous fibers of an oxidizing composition containing at least one oxidizing agent, followed possibly a time of installation. The oxidizing composition generally comprises one or more oxidizing agents chosen from hydrogen peroxide, urea peroxide, alkaline bromates, polythionates, persalts, such as perborates, percarbonates and persulfates. Preferably, the oxidizing agent is hydrogen peroxide. The oxidizing agent or agents generally represent from 0.1 to 10%, preferably from 0.5 to 5%, by weight relative to the total weight of the oxidizing composition.

Preferably, when the oxidizing agent is hydrogen peroxide in aqueous solution, the oxidizing composition used in the process according to the invention contains at least one stabilizing agent for hydrogen peroxide.

Mention may be made especially of alkaline or alkaline earth metal pyrophosphates, such as tetrasodium pyrophosphate, alkali or alkaline earth metal stannates, phenacetin or salts of acids and oxyquinoline, such as oxyquinoline sulphate. . More advantageously still, at least one stannate is used in combination or not with at least one pyrophosphate. The stabilizing agent (s) for hydrogen peroxide generally represent from 0.0001% to 5% by weight and preferably from 0.01 to 2% by weight relative to the total weight of the oxidizing composition.

Generally, the pH of the oxidizing composition ranges from 1.5 to 4.5, preferably from 2 to 3.5. Preferably, the oxidizing composition as defined above is allowed to act for about 2 to 30 minutes, preferably for 2 to 15 minutes, more particularly between 2 to 7 minutes.

The method according to the invention may comprise a step of removing the mechanical tensioning devices; a rinsing step, generally with water, optionally followed by a drying step. Preferably, the method which is the subject of the invention comprises a step of applying a care composition containing a non-silicone cationic polymer or a preferably aminated silicone. Among all the non-silicone cationic polymers which may be used in the context of the present invention, it is preferred to use in the reducing composition the cyclopolymers, in particular the homopolymers of dimethyldiallylammonium chloride sold under the name Merquat 100 by the company Merck. , quaternary diammonium polymers, and in particular MEXOMERE PO. The preferred silicone is the silicone WACKER BELSIL ADM LOG 1. A step of applying a care composition makes it possible to limit or avoid hair sensitization that could result from the treatment of the hair with reducing agents and oxidizing agents. during the permanent deformation process that is the subject of the invention. The care composition as defined above also makes it possible to protect the artificial color of the hair. The vehicle of the reducing, oxidizing and caring compositions is preferably an aqueous medium consisting of water and may advantageously contain cosmetically acceptable organic solvents, of which, more particularly, alcohols such as ethyl alcohol, alcohol and isopropyl alcohol, benzyl alcohol, and phenylethyl alcohol, or polyols or polyol ethers such as, for example, ethylene glycol monomethyl, monoethyl and monobutyl ethers, propylene glycol or its ethers such as, for example, propylene glycol monomethyl ether, butylene glycol, dipropylene glycol and diethylene glycol alkyl ethers, for example diethylene glycol monoethyl ether or monobutyl ether. The organic solvents may then be present in concentrations of between approximately 0.1 and 20% and, preferably, between approximately 1 and 10% by weight relative to the total weight of the composition. The pH of the oxidizing composition and of the care composition used in the process according to the invention can be obtained and / or adjusted conventionally by adding either one or more alkaline agents, such as those already mentioned in the reducing composition, or acidifying agents such as, for example, hydrochloric acid, acetic acid, lactic acid, boric acid, citric acid and phosphoric acid. The reducing composition, the oxidizing composition and the care composition used in the process according to the invention may be independently of one another in the form of a lotion, thickened or not, of a cream, a gel or foam.

The subject of the invention is also a kit associating: at least one means for mechanical tensioning of the keratinous fibers, and at least one means for covering said fibers, said mechanical tensioning means, said covering means or these two means including a heating means, a compartment containing a reducing composition with a pH of between 1 and 7, the terminals 1 and 7 being included. Preferably, the reducing composition comprises one or more agents chosen from thioglycolic acid, thiolactic acid, 3-mercaptopropionic acid, cysteamine, cysteine, one of their salts and one of their esters.

Optionally, the kit may contain a cosmetic composition containing at least one oxidizing agent.

Examples The following compositions were prepared (in percent by weight)

Composition 1 (Reference: reducing lotion) 10 Thioglycolic acid 6.8 Ammonium bicarbonate 2.8 Pentasodium pentetate (40% in aqueous solution) 0.4 Ammonia (20% in aqueous solution) qsp pH 8.7 Distilled water qs 100 Composition 2 (reducing lotion) Thioglycolic acid 1.0 Pentasodium pentetate (40% in aqueous solution) 0.4 Ammonia (20% in aqueous solution) qsp pH 5.0 Distilled water qs 100 Sodium bromate 8 Trisodium phosphate 0.4 Sodium phosphate 0.4 Citric acid qs pH 7.5 Distilled water qs 100 Thioglycolic acid 3.0 Pentasodium pentetate (40% in aqueous solution) 0.4 Ammonia (20% in aqueous solution) qsp pH 5.0 Distilled water qs 100 Composition 3 (reducing lotion) Composition 4 (oxidizing lotion) Example 1 (reference) Composition 1 was applied for 15 minutes on a lock of 1g of natural Japanese hair, previously wrapped on a curler of 1.7cm in diameter. After the break time, the hair was rinsed and the composition 4 was applied for 10 minutes. The hair was then unwound, rinsed and air dried. Example 2 (Invention) The composition 2 was applied to a lock of natural Japanese hair of 1 g previously wound on a curler composed of a polyethylene cylinder 1.7 cm in diameter (the curler itself) covering an electrical resistance. The hair curler was then covered with a polychlorovinylidene plastic film and connected by an electrical connection to a Digital Perm device (Oohiro, model ODIS-2) delivering a power of 10W per curler. The hair was thus heated at 90 ° C for 15 minutes. At the end of the break time, the plastic film is removed, the hair has been rinsed. At the end of this pause time, the composition 4 was applied to the hair for 10 minutes. At the end of this pause time, the hair was unwound, rinsed and then dried in the open air.

Example 3 (Invention) The composition 2 was applied to a lock of natural Japanese hair of 1 g previously wound on a curler composed of a polyethylene cylinder 1.7 cm in diameter (the curler itself) covering an electrical resistance. The hair curler was then covered with a polychlorovinylidene plastic film and connected by an electrical connection to a Digital Perm device (Oohiro, model ODIS-2) delivering a power of 10W per curler. The hair was thus heated at 90 ° C for 15 minutes. At the end of the break time, the plastic film is removed, the hair has been rinsed and then dried in the open air.

Example 4 (Invention) Composition 2 was applied for 15 minutes on a lock of natural Japanese hair of 1 g previously wound on a curler composed of a polyethylene cylinder of 1.7 cm in diameter (the curler itself) covering a resistor electric. At the end of the break time, the plastic film is removed, the hair has been rinsed. The hair curler was then covered with a polychlorovinylidene plastic film and connected by an electrical connection to a Digital Perm device (Oohiro, model ODIS-2) delivering a power of 10W per curler. The hair was thus heated at 90 ° C for 30 minutes. After the break time, the hair has been rinsed. At the end of this pause time, the composition 4 was applied to the hair for 10 minutes. At the end of this pause time, the hair was unwound, rinsed and then dried in the open air.

Example 5 (Invention) The composition 2 was applied for 15 minutes on a lock of natural Japanese hair of 1 g previously wound on a curler composed of a polyethylene cylinder of 1.7 cm in diameter (the curler itself) covering a resistor electric. At the end of the break time, the plastic film is removed, the hair has been rinsed. The hair curler was then covered with a polychlorovinylidene plastic film and connected by an electrical connection to a Digital Perm device (Oohiro, model ODIS-2) delivering a power of 10W per curler. The hair was thus heated at 90 ° C for 30 minutes. At the end of the break time, the plastic film is removed, the hair has been rinsed and then dried in the open air.

Example 6 (Invention) The composition 3 was applied to a lock of natural Japanese hair of 1 g previously wound on a curler composed of a polyethylene cylinder 1.7 cm in diameter (the curler itself) covering an electrical resistance. The hair curler was then covered with a polychlorovinylidene plastic film and connected by an electrical connection to a Digital Perm device (Oohiro, model ODIS-2) delivering a power of 10W per curler. The hair was thus heated at 90 ° C for 15 minutes. After the break time, the hair has been rinsed. At the end of this pause time, the plastic film is removed, the composition 4 was applied to the hair for 10 minutes. At the end of this pause time, the hair was unwound, rinsed and then dried in the open air.

A durability test of the artificial loop was carried out on the locks of hair thus treated in Examples 1 to 6. For this purpose, the locks were kept taut for 5 hours at 40 ° C. and in a relative humidity of 100%. . The behavior of the loops is evaluated by comparing the crimp before and after the test.

Reduction Process of the Invention Durability Fastening Curl of the Loop Example 1 Composition 1 15 min. Composition 4 + 10 min. Example 2 Composition 2 Example 3 Composition 2 Example 4 Composition 2 90 ° C 15 min. min. 90 ° C to 15min. 90 ° C to 15min. Composition 4 Composition 4 10 min. 10 minutes. Composition 2 90 ° C Example 5 - + + 15 min. min. Example 6 Composition 3 90 ° C to 15min. Composition 4 10 min. ++ + ++: Very high loop efficiency +: Good loop efficiency 5 -: Poor loop efficiency

Claims (10)

REVENDICATIONS1. Process for the permanent deformation of keratinous fibers, in particular the hair, comprising: a) a step of mechanically tensioning the keratinous fibers by winding them on mechanical tensioning means so as to form loops, then b ) a step of applying to the keratin fibers of an acidic reducing composition, then c) a possible rinsing step of the keratinous fibers, then d) a step of setting up a means for covering said energizing means mechanical means for forming a closed space intended to maintain a temperature of between 50 and 250 ° C., then e) a possible oxidation fixing step, characterized in that at least one of said mechanical tensioning means and said means for recovery is a means of heating. 2. Method according to claim 1, characterized in that the method comprises a step c) of rinsing the keratin fibers, following step b) of application to the keratinous fibers of a reducing composition. 3. Method according to claim 1 or 2, characterized in that the heating means is the covering means. 4. Method according to any one of claims 1 to 3, characterized in that the mechanical tensioning means is selected from a curler, a roller and a gripper. 25 5. Method according to any one of claims 1 to 4, characterized in that the covering means is rigid. 6. Method according to any one of claims 1 to 4, characterized in that the covering means is flexible. 7. Method according to claim 6, characterized in that the covering means is selected from a film, a sheet, a textile or a cap. 8. Process according to any one of claims 1 to 7, characterized in that the reducing composition comprises thioglycolic acid and / or thiolactic acid and / or mercaptopropionic acid and / or monothioglycerol and / or cysteamine. and / or a salt thereof and / or an ester thereof. 9. Process according to claim 8, characterized in that the reducing agent or agents represent between 0.01% and 20% relative to the total weight of the reducing composition. 10. Kit associating at least - a device comprising: - at least one means for mechanical tensioning keratinous fibers, and - at least one means for covering said fibers, said mechanical tensioning means, said cover means, or these two means being a heating means, and a compartment containing a reducing composition as defined in any one of claims 1 to 9.