Process for straightening keratin fibres with a heating means and denaturing agents

Abstract

The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.

1 . Process for relaxing keratin fibres, comprising:
 (i) applying to the keratin fibres a hair-relaxing composition containing at least two denaturing agents,   (ii) raising the temperature of the keratin fibres, using a heating means, to a temperature of between 110 and 250° C.   
   
   
       2 . Process according to  claim 1 , wherein the pH of the composition is less than 7. 
   
   
       3 . Process according to  claim 1 , wherein the hair-relaxing composition comprises an overall concentration of between 2 M and 8 M of the said denaturing agents. 
   
   
       4 . Process according to  claim 1 , wherein the temperature is raised to a temperature of between 140° C. and 220° C. 
   
   
       5 . Process according to  claim 1 , wherein the molar mass of the denaturing agents is between 40 and 600 g/mol. 
   
   
       6 . (canceled) 
   
   
       7 . (canceled) 
   
   
       8 . Process according to  claim 1 , wherein the denaturing agents are chosen from ureas, guanidines, α-hydroxy acid and α-keto acid derivatives, mono-, di-, tri- or polyhydroxylated aromatic derivatives, cyclic or linear amides, surfactants or detergents, amidines, thioureas, urethanes, alcohols, polyols, amine oxides, metal salts, sulfamides, carboxylic acids, amino acids, and nitrogenous heterocycles of the imidazole or triazole family. 
   
   
       9 . Process according to  claim 1 , wherein at least one of the denaturing agents is a urea. 
   
   
       10 . Process according to  claim 9 , wherein the urea corresponds to formula (I): 
     
       
         
         
             
             
         
       
       in which: 
       R1, R2, R3 and R4 represent, independently: 
       (v) a hydrogen atom or 
       (vi) a linear or branched C1-C4 lower alkyl or alkenyl radical, optionally substituted with a radical chosen from: hydroxyl, amino, dimethylamino, carboxyl or carboxamide or N-methylcarboxamide, 
       when R1, R2 and R3 represent a hydrogen atom, R4 may also denote a radical chosen from: carboxamide; methoxy; ethoxy; 1,2,4-triazolyl; cyclopentyl; methoxycarbonyl; ethoxycarbonyl; CO—CH═CH—COOH; phenyl optionally substituted with a chlorine atom or a hydroxyl radical; benzyl; or 2,5-dioxo-4-imidazolidinyl, 
       when R1 and R3 represent a hydrogen atom, R2 may also represent a hydrogen atom or a methyl or ethyl radical and R4 an acetyl radical, 
       when R1=R2=H, R3 and R4 may also form, with the nitrogen atom that bears them, a piperidine or 3-methylpyrazole or 3,5-dimethylpyrazole or maleimide ring, 
       R1 and R2 and also R3 and R4 may also form, with the nitrogen atom that bears them, an imidazole ring. 
     
   
   
       11 .- 13 . (canceled) 
   
   
       14 . Process according to  claim 1 , wherein at least one of the denaturing agents is a guanidine of general formula (III) below: 
     
       
         
         
             
             
         
       
       in which: 
       R1, R2, R3, R4 and R5 represent, independently: 
       (vii) a hydrogen atom or 
       (viii) a linear or branched C1-C4 lower alkyl or alkenyl radical, optionally substituted with one or two radicals chosen from: hydroxyl, amino, dimethylamino, methoxy, ethoxy, carboxyl, carboxamide, N-methylcarboxamide or SO 3 H, 
       when R1, R2 and R3 and R4 represent a hydrogen atom, R5 may also denote a radical chosen from the following: acetyl; chloroacetyl; carboxamide; methoxy; ethoxy; 1,2,4-triazolyl; cyclopentyl; methoxycarbonyl; ethoxycarbonyl; CO—CH═CH—COOH; phenyl optionally substituted with a chlorine atom or a hydroxyl radical; benzyl; thiazolidone; benzimidazole; benzoxazole; benzothiazole; or C(═NH)—NR6R7 in which R6 and R7 denote, independently of each other, a hydrogen atom or a linear or branched C1-C4 lower alkyl radical, optionally substituted with one or two radicals chosen from: hydroxyl, amino, dimethylamino, carboxyl or carboxamide; or N-methylcarboxamide; or alternatively a phenyl radical, 
       when R1=R2=R3=H, R4 and R5 may also form, with the nitrogen atom that bears them, a pyrrolidine, piperidine, pyrazole or 1,2,4-triazole ring optionally substituted with one or two radicals chosen from: hydroxyl, amino or carboxyl, 
       when R1=R2=H and R4=H or methyl, R3 and R5 may also together form a 5-membered ring optionally containing an oxo group, 
       and the organic or mineral salts thereof. 
     
   
   
       15 .- 18 . (canceled) 
   
   
       19 . Process according to  claim 1 , wherein at least one of the denaturing agents is a α-keto acid derivative of general formula (V): 
     
       
         
         
             
             
         
       
       R5 represents COOH, a linear or branched C1-C6 alkyl optionally substituted with an OH, COOH or Br radical; a phenyl or benzyl optionally substituted with an OH or COOH radical; or alternatively an indolyl radical or 
     
     
       
         
         
             
             
         
       
       and the stereoisomers, organic or mineral salts and solvates thereof. 
     
   
   
       20 .- 33 . (canceled)