The present invention relates to a method for shaping keratin fibers, in particular human keratin fibers such as the hair, comprising a step of applying onto the keratin fibers a reducing composition (A) and a step of applying onto the keratin fibers a composition (B) comprising one or more particular diacidic compounds.
The present invention also relates to a cosmetic composition comprising one or more particular diacidic compounds and one or more chemical oxidizing agents; as well as the use thereof for shaping keratin fibers.
Many people are not satisfied with the appearance of their hair. In order to obtain a permanent deformation of the hair, the most widely used technique consists, initially, in opening the disulfide -SS-linkages of keratin (keratocystin) using a generally basic composition containing a thiol reducing agent (reduction step) and then, after having generally rinsed the treated hair with water, to reconstitute in a second step the said disulfide bonds by applying onto the hair an oxidizing composition (oxidation step, also known as a fixing step ) so as to finally give the hair the desired shape.
Many products for hair shaping exist on the market, and they generally contain an oxidizing composition, required for carrying out the fixing step.
However, these products generally contain relatively high concentrations of hydrogen peroxide, which can induce, in the long run, an alteration in the quality of the hair fibers resulting in a decrease in their cosmetic properties, such as their vitality, their gloss and a degradation of their mechanical properties, more particularly their mechanical strength.
Therefore, there is a real need to develop novel methods for shaping keratin fibers which can reduce the damage to keratin fibers and preserve their mechanical properties. Such methods shall allow achieving satisfying results in terms of permanent

waving/straightening/relaxing and shall allow reducing, or even deleting, the use of chemical oxidizing agents such as hydrogen peroxide.
This aim is achieved by the present invention, one subject of which is a method for shaping keratin fibers, in particular human keratin fibers such as the hair, comprising:
- a step (i) of applying onto the keratin fibers a composition (A) comprising one or more reducing agents ; then
- a step (ii) of applying onto the keratin fibers a composition (B) comprising one or more diacidic compounds chosen from the compounds of formula (I) ; geometrical isomers thereof; optical isomers thereof ; salts thereof; and mixtures thereof:
HOOC-C(R2)=C(Ri)-C(0)-A-B-A-C(0)-C(Ri)=C(R2)-COOH (I)
in which:
-A represents an oxygen atom, a sulfur atom, or an -NH- group ; -B represents a linear or branched Ci-Cis hydrocarbon chain, optionally interrupted by one or more: o oxygen atoms, o sulfur atoms, o -NH- groups,
o -N(R')- groups wherein R' represents a linear or branched Ci-C4 alkyl group, optionally substituted with one or more hydroxy groups, and/or o -N+(R")(R'")- groups wherein R" and R'" represent, independently, a linear or branched C1-C4 alkyl group, optionally substituted with one or more hydroxy groups ; -Ri and R2 each represent, independently, a hydrogen atom, or a linear or branched C1-C3 alkyl group.
The method according to the invention makes it possible to achieve a permanent shaping of keratin fibers while using reduced

amount of chemical oxidizing agents compared to conventional methods.
In some embodiments, the method according to the invention makes it possible to efficiently shape keratin fibers without applying any chemical oxidizing agents.
Moreover, the method according to the invention is more respectful of the quality of the fiber when compared to conventional methods.
Furthermore, the method of the invention allows achieving a very efficient level of hair shaping, such as hair waving or hair relaxing or hair straightening, that is long lasting and remanent after several shampoos, especially after 10 shampoos.
Other characteristics and advantages of the invention will emerge more clearly on reading the description and the examples that follow.
In the present description and unless otherwise indicated:
-the limits of a range of values are included within this range, in particular in the expressions "of between... and ..." and "ranging from ... to...";
-the expression "at least one" used in the present description is equivalent to the expression "one or more" and may be substituted for it.
Reducing agents
According to the invention, the method comprises the application of a composition (A) further containing one or more reducing agents.
Preferably, the reducing agent(s) is(are) selected from thiol reducing agents, non-thiol reducing agents, salts thereof, and mixtures thereof.
The expression "thiol reducing agent" means a reducing agent containing at least one thiol group. The thiol reducing agent(s) may

preferably be chosen from the group consisting of thioglycolic acid and derivatives thereof, in particular esters thereof such as glycerol or glycol monothioglycolate; thiolactic acid and derivatives thereof, in particular esters thereof such as glycerol monothiolactate; 3-mercaptopropionic acid and derivatives thereof, in particular esters thereof such as glycerol 3-mercaptopropionate and ethyleneglycol 3-mercaptopropionate; cysteamine and derivatives thereof, in particular Cl-4 acyl derivatives thereof such as N-acetylcysteamine and N-propionylcysteamine; mono-thioglycerol and derivatives thereof, in particular esters; cysteine and derivatives thereof, in particular esters such as N-acetylcysteine, N-alkanoylcysteine and cysteine alkyl esters; and salts thereof.
As the above salts, mention may be made of, for example, ammonium salts; primary-, secondary- or tertiary-amine salts; alkaline metal salts; and, alkaline earth metal salts. As the primary-, secondary- or tertiary-amine, for example, monoethanolamine, di-isopropanolamine or triethanolamine, respectively, may be mentioned.
Other suitable examples of the thiol reducing agent that may be used in the cosmetic composition for the present invention include, but are not limited to, sugar N-mercapto alkyl amides such as N-(mercapto-2-ethyl)gluconamide, P-mercaptopropionic acid and derivatives thereof; thiomalic acid; pantheteine; N-(mercaptoalkyl)co-hydroxyalkyl amides such as those described in EP354835 and N-mono- or N,N-dialkylmercapto 4-butyramides such as those described in EP368763; aminomercaptoalkyl amides such as those described in EP432000 and alkylaminomercaptoalkylamides such as those described in EP514282; hydroxy-2 propyl thioglycolate; and the hydroxy-2 methyl-1 ethyl thioglycolate-based mixture (67/33) described in FR2679448.
Preferably, the thiol reducing agent(s) is/are used in a total amount ranging from 0.01 to 20% by weight, preferably from 0.01 to 15%) by weight, more preferably from 0.1 to 10%> by weight, and even more preferably from 1.0 to 10%> by weight, relative to the total weight of the composition (A).

The expression "non-thiol reducing agent" means a reducing agent which does not contain any thiol group. The non-thiol reducing agent(s) may preferably be chosen from the group consisting of sulfites, bisulfites, sulfinates, phosphines, sugars, dihydroxybenzene derivatives, reductones and hydrides. More preferably, the non-thiol reducing agent may be selected from ammonium sulfites and bisulfites as well as metal sulfites and bisulfites, more preferably alkali metal or alkali earth metal sulfites and bisulfites, and more preferably sodium sulfites and bisulfites.
As sulfinates, mention may be made of sulfinic acid salts, and benzenesulfinic acid salts such as sodium salts thereof. The sulfinic acid derivatives as described in FR-A-2814948 can also be used. A preferred sulfinate compound is 2-hydroxy-2-sulfinatoacetic acid, disodium salt.
As phosphines, mention may be made of monophosphine and diphosphines as described in FR-A-2870119.
According to one particular embodiment of the invention, the phosphine(s) that is (are) useful in the context of the invention is (are) soluble in a cosmetically acceptable medium. Preferably, the phosphine(s) that is (are) useful in the context of the invention is (are) water-soluble.
In the context of the present invention, the term "water-soluble" means any phosphine whose solubility in water is greater than 0.01 wt% at 20°C. Preferably, the phosphine is tri hydroxy methyl phosphine.
As sugars, mention may be made of ribose, glucose, maltose, galactose, lactose, and xylose.
As dihydroxybenzene derivatives, mention may be made of catechol, resorcinol, gallic acid, para-hydroxyphenol or resveratrol.

In a manner known per se, the term "reductone" refers to a compound comprising an endiol -(HO)C=C(OH)- adjacent to a carbonyl >C=0 group.
Thus, the reductone(s) that can be used in the present invention
are preferably of following general formula as well as their salts; and /
or mixtures thereof:
R—(HO)C=C(OH) C—R2
O
with Ri and R2, which may be identical or different, each denoting a group containing at least one carbon and / or oxygen atom, Ri and R2 being able to form with the three carbon atoms of the compound of the above general formula a ring, preferably a 5 or 6-membered ring; the additional constituent atoms of which consist of carbon and/or oxygen atoms.
Preferably, Ri and R2 form, with the three carbon atoms of the compound of the above general formula, a 5-carbon and/or oxygen ring.
The compound(s) of the above general formula may be present in acid form or in the form of salts, in particular in the form of alkali metal salts such as sodium and potassium, or alkaline earth metal salts such as calcium and magnesium, or in the form of esters, in particular esters of C8-C30 fatty acids.
More preferably, the compounds of the above general formula are lactones.
The reductone(s) may in particular be chosen from reductive acid, ascorbic acid, erythorbic acid or isoascorbic acid, and the salts of these compounds, in particular sodium or potassium salts, ascorbyl palmitate , and mixtures of these compounds.
In a particularly preferred manner, the reductone(s) is(are) chosen from ascorbic acid, erythorbic acid and the salts of these compounds, in particular the sodium or potassium salts.
As hydrides, mention may be made of boron hydrides such as sodium borohydride, lithium hydride, and phosphorous hydride.

Precursors of hydrides and especially of boron hydrides such as diborane, tetraborane, pentaborane, decaborane and dodecaborane can be used.
Preferred non-thiol-based reducing agents are chosen from sulfites, bisulfite, dihydroxybenzene derivatives and reductones.
Preferably, the non-thiol reducing agent(s) is/are used in a total amount of from 0.01 to 10% by weight, preferably from 0.01 to 5.0% by weight, more preferably from 0.1 to 4.0%> by weight, and even more preferably from 1.0 to 4.0%> by weight, relative to the total weight of composition (A).
In a preferred embodiment of the invention, the composition
(A) comprises one or more reducing agents chosen from thiol reducing
agents and salts thereof; and more preferably from thioglycolic acid,
thiolactic acid, cysteine, cysteamine, homocysteine, glutathione,
thioglycerol, thiomalic acid, 2-mercaptopropionic acid, 3-
mercaptopropionic acid, thiodiglycol, 2-mercaptoethanol,
dithiothreitol, thioxanthine, thiosalicylic acid, thiodiglycolic acid, lipoic acid, N-acetylcysteine, and thioglycolic or thiolactic acid esters and amides, in particular glyceryl monothioglycolate, salts thereof, and mixtures of these compounds, preferably thioglycolic acid and salts thereof.
Preferably, the reducing agent(s) represents from 0.01 to 20%> by weight, more preferably from 0.01 to 15%> by weight, even more preferably from 0.1 to 10%> by weight, and even better from 1.0 to 10%> by weight, relative to the total weight of composition (A).
Diacidic compounds - The method of the invention comprises the application of a composition (B) containing one or more diacidic compounds

chosen from the compounds of formula (I) ; geometrical isomers thereof; optical isomers thereof ; salts thereof; and mixtures thereof:
HOOC-C(R2)=C(Ri)-C(0)-A-B-A-C(0)-C(Ri)=C(R2)-COOH (I)
in which:
-A represents an oxygen atom, a sulfur atom, or an -NH- group ; -B represents a linear or branched Ci-Cis hydrocarbon chain, optionally interrupted by one or more: o oxygen atoms, o sulfur atoms, o -NH- groups,
o -N(R')- groups wherein R' represents a linear or branched Ci-C4 alkyl group, optionally substituted with one or more hydroxy groups, and/or o -N+(R")(R'")- groups wherein R" and R'" represent, independently, a linear or branched C1-C4 alkyl group, optionally substituted with one or more hydroxy groups ; -Ri and R2 each represent, independently, a hydrogen atom, or a linear or branched C1-C3 alkyl group.
Preferably, A represents an oxygen atom or a -NH- group, and more preferably a -NH- group.
Preferably, B represents a linear or branched C1-C18, more preferably C3-C18, even better linear C3-C12, hydrocarbon chain, optionally interrupted by one or more oxygen atoms, one or more sulfur atoms, and/or one or more -NH- groups.
Preferably, Ri and R2 each represent, independently, a hydrogen atom or a methyl radical; and more preferably Ri and R2 both represent a hydrogen atom.

In a preferred embodiment of the invention, the diacidic compound(s) of formula (I) is(are) chosen from the following compounds (1) to (8):

HOOC-CH=CH-C(0)NH-(CH2CH20)2- (CH2)2-NHC(0)-CH=CH-COOH
(1)
HOOC -CH=CH-C(0)NH- CH2-(CH2CH20; )3-(CH2)3 -NHC(0)-CH=CH- ■COOH
(2)
HOOC-CH=CH-C(0)NH-(CH2)2-S-S-(CH2)2-NHC(0)-CH=CH-COOH
(3)
HOOC -CH=CH-C(0)NH- CH2-(CH2CH20; )2-(CH2)3 -NHC(0)-CH=CH- ■COOH
(4)
HOOC- ■CH=CH -C(0)-0-(CH2)3
(5) -O-C(O)- CH=CH-COOH
HOOC- ■CH=CH -C(0)-0-(CH2)4
(6) -O-C(O)- CH=CH-COOH
HOOC- ■CH=CH -C(0)-0-(CH2)6
(7) -O-C(O)- CH=CH-COOH
HOOC- ■CH=CH -C(0)-0-(CH2)8
(8) -O-C(O)- CH=CH-COOH
5
The diacidic compounds of formula (I) may be in a (Z)/(Z), or
a (Z)/(E), or a (E)/(Z), or a (E)/(E) isomerism.
Preferably, the diacidic compound(s) of formula (I) has(have) the following (Z)/(Z) structure :

0 0 0 0
JK /^\ /B-- J\ J^ HO f=\ A A /=\ OH
R2 R* R* Rn
According to the invention, the compounds of formula (I) may be in salt form. In other words, each carboxylic acid function of the compounds of formula (I) may be in the form of a carboxylate function salified by a cation or a cosmetically acceptable cationic group. Said cation or cosmetically acceptable cationic group is derived from an organic or inorganic base salt associated with the anionic charge of the carboxylate acid function; more particularly the cationic counterion is selected from i) alkali metals such as Na+ and K+, ii) alkaline earth metals such as Ca++, and Mg++, and iii) ammoniums such as RaRbRcRdN+ with Ra, Rb, Re and Rd, which may be identical or different, represent a hydrogen atom or a hydroxy or (Ci-Cs) alkyl group.
According to one particular embodiment of the invention, the synthesis of the compounds of formula (I) can be carried out according to three synthetic strategies, respectively illustrated by the following schemes (1) to (3).
Z/E ■R1 H H R1
O O
(d)
R2
OH
2 \=/ + H2N NH2 ~ V
O
R2 RI non-polar solvent o
(a1) (b1)
Scheme 1.
In order to obtain compounds of formula (I) of bis-amine carboxylic type, that is to say wherein A denotes -NH-, the diamine compound (bl) is solubilized in a non-polar solvent, such as dichloromethane. Two equivalents of anhydride (al) are then added to the reaction in order to obtain the bis-amine carboxylic of formula (I).

12
Possible examples of the synthesis of bis-amine carboxylic of formula (I) are described in the patent application WO2014/0073717.

5

Z / E
2 \=(
R2 R1 + HO OH H+ R2 O R1 R1 R2 =C.O^ ^O^}=C.OH
O O O

non-polar solvent

(a2) (b2) Scheme 2. (c2)

10

In order to obtain compounds of formula (I) of bis-ester carboxylic type, that is to say wherein A represents an oxygen atom, the diester compound (b2) is solubilized in a non-polar solvent, such as toluene. Two equivalents of anhydride (a2) and a sufficient amount of an organic acid, such as paratoluenesulfonic acid, are then added to the reaction in order to obtain the bis-ester carboxylic of formula (I). Possible examples of the synthesis of bis-ester carboxylic of formula (I) are described in the patent application WO2008/121895.

15

-Bv
OyOyO
2 \=I + HS' "SH
R2 R1
(b3)
(a3)

H+
non-polar solvent
Scheme 3.

Z / E
R2 R1 R1 R2
O
O
O
O
(c3)

20

In order to obtain compounds of formula (I) of bis-thioester carboxylic type, that is to say wherein A represents an sulfur atom, the dithioester compound (b3) is solubilized in a non-polar solvent, such as toluene. Two equivalents of anhydride (a3) and a sufficient amount of an organic acid, such as paratoluenesulfonic acid, are then added to the reaction in order to obtain the bis-thioester carboxylic of formula (I).

25 In all the schemes above, B is as previously defined and the
compounds c1, c2 and c3 also represent all possible Z/E isomeri c forms thereof.

13
Preferably, the diacidic compound(s) represents from 0.1 to 15% by weight, more preferably from 0.5 to 10% by weight, particularly from 0.8 to 8% by weight, even better from 1 to 5% by weight, relative 5 to the total weight of composition (B).
Alkaline agents
According to the invention, the reducing composition (A) may
optionally further contain one or more alkaline agents.
10 The alkaline agent(s) used in composition (A) may be any
agent capable of increasing the pH of the composition in which it is present. The alkaline agent may be a Brönsted-Lowry or Lewis base. It may be mineral or organic.
In particular, the alkaline agent(s) may be chosen from:
15 a) aqueous ammonia,
b) alkanolamines such as mono-, di- and triethanolamine,
isopropanolamine and 2-amino-2-methyl-1-propanol, and
also derivatives thereof,
c) oxyethylenated and/or oxypropylenated ethylenediamines,
20 d) mineral or organic hydroxides,
e) alkali metal silicates such as sodium metasilicates,
f) amino acids, preferably basic amino acids, such as arginine, lysine, ornithine, citrulline and histidine,
g) carbonates and bicarbonates, particularly of a primary
25 amine, secondary amine or tertiary amine, or of an alkali
metal or alkaline-earth metal, or of ammonium, and h) the compounds of formula (II) below:
Rx Rz

30

N-W-N
Ry
Rt
(II)
in which W is a C1-C6 alkylene residue optionally substituted with a hydroxyl group or a C1-C6 alkyl radical; Rx, Ry, Rz and Rt,

14
which may be identical or different, represent a hydrogen atom or a C1-C6 alkyl, C1-C6 hydroxyalkyl or C1-C6 aminoalkyl radical.
Examples of such compounds of formula (II) that may be
mentioned include 1,3-diaminopropane, 1,3-diamino-2-propanol,
5 spermine and spermidine.
The mineral or organic hydroxides are preferably chosen from
hydroxides of an alkali metal, hydroxides of an alkaline-earth metal,
for instance sodium hydroxide or potassium hydroxide, hydroxides of a
transition metal, such as hydroxides of metals from groups III, IV, V
10 and VI of the Periodic Table of the Elements, hydroxides of
lanthanides or actinides, quaternary ammonium hydroxides and guanidinium hydroxide.
The hydroxide may be formed in situ, for instance guanidine
hydroxide, by reacting calcium hydroxide and guanidine carbonate.
15 The preferred alkaline agents are in particular aqueous
ammonia, ammonium carbonate, ammonium bicarbonate, arginine, monoethanolamine and 2-amino-2-methyl-1-propanol.
More preferably, the alkaline agent is ammonium bicarbonate.
Mentions may be made of the product available on the market,
20 such as the one under the name Ammonium Bicarbonate sold by the
company Pesquisa.
The concentration of alkaline agent(s) is especially adjusted as a function of the pH desired for the composition.
Preferably, the composition (A) used in the method of the
25 present invention has a pH ranging from 7 to 10 and more
preferentially from 7 to 9.5.
According to a preferred embodiment of the invention,
composition (A) further contains one or more alkaline agents as
defined above. Preferably, these alkaline agent(s) represents from
30 0.001% to 20% by weight, and more preferably from 0.005% to 10%
by weight, relative to the total weight of composition (A).
Chemical oxidizing agents

15
The method may optionally further comprise applying onto the fibers of one or more chemical oxidizing agents.
Preferably, the chemical oxidizing agent(s) is(are) chosen from
hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such
5 as perborates and persulfates, peracids and enzymes oxidases (with
their possible cofactors), among which may be mentioned peroxidases, 2-electron oxidoreductases such as uricases and 4-electron oxygenases, such as laccases. More preferably, the chemical oxidizing agent is hydrogen peroxide. 10
According to a preferred embodiment of the invention, the
chemical oxidizing agent(s) is(are) present in the composition (B).
According to this embodiment, the chemical oxidizing agent(s) ranges
from 0.05 to 30% by weight, preferably from 0.1 to 20% by weight,
15 relative to the total weight of the composition (B).
According to another preferred embodiment of the invention, the chemical oxidizing agent(s) is(are) present in a separate composition (C). According to this embodiment, the composition (C)
20 is applied onto the fibers in a separate step (iii), which is carried out
after step (ii). Still according to this embodiment, the chemical oxidizing agent(s) ranges from 0.05 to 30% by weight, preferably from 0.1 to 20% by weight, relative to the total weight of the composition (C).
25 According to a variant of the method of the invention, no
chemical oxidizing agent is applied onto the fibers.
“No chemical oxidizing agent is applied onto the fibers” here means that no chemical oxidizing agent is present in any one of the composition that are applied onto the fibers during the hair shaping
30 method, or in case such chemical oxidizing agent(s) is(are) present,
it(they) represents less than 0.1% by weight relative to the total weight of the composition(s) containing them.

16
Surfactants
The compositions (A) and/or (B) according to the invention
may optionally further comprise at least one surfactant selected from
anionic surfactants, nonionic surfactants, amphoteric or zwitterionic
5 surfactants and cationic surfactants, and mixtures thereof.
Preferably, the surfactant(s) is(are) present in an amount
ranging from 0.01 to 30% by weight, more preferably from about 0.1
to about 25% by weight, even better from 0.5 to 15% by weight,
10 relative to the total weight of each composition containing them.
Solvents
According to the invention, compositions (A) and (B) each
comprise a cosmetically acceptable solvent.
15 When the process according to the invention comprises the
application of a composition (C) in a step (iii), composition (C) comprises a cosmetically acceptable solvent.
The cosmetically acceptable solvent(s) present in each
20 composition may be identical or different and are preferably selected
from water, organic solvents, and mixtures thereof. Water that is
suitable for use in the invention may be a floral water such as
cornflower water and/or a mineral water such as Vittel water, Lucas
water or La Roche Posay water and/or a spring water and/or tap water
25 and/or well water.
The organic solvents that may be used are preferably water-
miscible (at room temperature: 25°C). The water-miscible organic
solvents can be chosen from monoalcohols containing from 2 to 6
carbon atoms, such as ethanol or isopropanol; polyols especially
30 containing from 2 to 20 carbon atoms, preferably containing from 2 to
10 carbon atoms and preferentially containing from 2 to 6 carbon atoms, such as glycerol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol or diethylene glycol; glycol ethers (especially containing from 3 to 16 carbon atoms) such

17
as mono-, di- or tripropylene glycol (C1-C4)alkyl ethers, mono-, di- or triethylene glycol (C1-C4)alkyl ethers, and mixtures thereof.
In certain embodiments of the present invention, the organic
solvent is chosen from propylene glycol, glycerin, and mixtures
5 thereof.
In some embodiments, the cosmetically acceptable solvent comprises 100% water by weight.
In particular, the compositions (A), (B) and (C) of the
invention may independently of each other comprise water in a content
10 ranging from 45% to 99.9% by weight, preferably from 50% to 99% by
weight, more preferably from 60% to 98% by weight, relative to the
total weight of each composition.
The compositions (A) and/or (B) according to the invention
15 may also comprise any auxiliary ingredient usually used in the
cosmetic field. Such ingredients may be selected, for example, from
emulsifying agents, conditioning agents, stabilizers such as sodium
chloride, magnesium dichloride or magnesium sulfate, moisturizing
agents, shine agents, fillers, colorants, pigments, chelating
20 compounds, sequestering agents, fragrances, preservatives, stabilizers,
and mixtures thereof.
It is a matter of routine operations for a person skilled in the
art to adjust the nature and amount of the additives present in the
compositions in accordance with the invention such that the desired
25 cosmetic properties and stability properties thereof are not thereby
affected.
According to a preferred embodiment, the method according to
the invention comprises the following steps:
30 - applying the reducing composition (A) as described
previously onto wet or dry hair, and then
- leaving composition (A) to stand onto the hair, during a leave-on time ranging from 1 to 60 minutes and preferably from 2 to 30 minutes, and then

18
- optionally rinsing the hair with water,
- optionally heating the hair during 1 to 35 minutes at a
temperature ranging from 30 to 250°C, and then
- applying the composition (B) as described previously, onto
5 the hair,
- leaving composition (B) to stand on the hair, during a leave-
on time ranging from 30 seconds to 15 minutes and preferably from 1
to 10 minutes,
- optionally applying a composition (C) as previously
10 described, onto the hair and leaving said composition (C) to stand on
the hair, during a leave-on time ranging from 30 seconds to 15 minutes and preferably from 1 to 10 minutes, and then
- rinsing the hair with water.
15 Preferably, the hair is rinsed between application of
composition (A) and composition (B).
The hair may then be dried, for example by means of a drying hood or a hairdryer, or may be left in the open air.
20 Thus, according to a particularly preferred embodiment of the
invention, the method comprises the following steps:
- applying the reducing composition (A) onto the hair, and then
- leaving composition (A) to stand on the hair, during a leave-on time ranging from 1 to 60 minutes and preferably from 2 to 30
25 minutes, and then
- rinsing the hair with water, then
- optionally, heating the hair at a temperature ranging from 80 to 160°C, preferably from 100 to 140°C, and even more preferably of 120°C, then
30 - applying the composition (B) onto the hair,
- leaving composition (B) to stand on the hair, during a leave-on time ranging from 30 seconds to 15 minutes and preferably from 1 to 10 minutes, and then
- rinsing the hair with water.

19
In order to obtain a substantial alteration of the shape of the
keratinous fibres, the method of the invention preferably includes
placing said fibres under mechanical tension. The mechanical tension
5 can be applied during all steps of the claimed method, or during
particular steps thereof.
According to a preferred embodiment, the fibers are placed
under mechanical tension at least when they are in contact with the
reducing composition (A), as this composition is applied in order to
10 reduce the disulfide links in the keratin. In this embodiment the
keratinous fibers are placed under mechanical tension before, during or after application of the reducing composition (A).
When a perming operation is desired, preference is given to
using mechanical hair-shaping means such as curlers in order to place
15 the keratinous fibers under tension. The reducing composition (A)
according to the invention can be applied before, during or after said
hair-shaping means, preferably after.
The reducing composition (A) may be applied to hair which has
been wound beforehand onto rollers with a diameter of from 1 to
20 100mm, preferably from 2 to 50mm. The reducing composition may
also be applied in line with the winding of the hair.
Following application of the reducing composition according to
the invention, it is also possible to subject the whole hair to a heat
treatment by heating at a temperature of between 30 and 250°C for all
25 or part of the leave-on time. In practice, this operation may be
performed using a hairstyling hood, a hairdryer, a round or flat iron, an infrared ray dispenser and other heating appliances.
In particular it is possible, as heating means, to use heating
tongs at a temperature of between 60 and 230°C, and preferably
30 between 120 and 230°C, the heating tongs being preferably used after
the step of interim rinsing following the application of the reducing
composition.

20
As hair-shaping means with curlers, the temperature can be from 40 to 150°C, preferably from 60 to 120°C. The curler itself may be a heating means.
In the case of a hair relaxing or straightening process, after the
5 reducing composition (A) is applied to the hair, the hair can then be
subjected to mechanical deformation for fixing the hair in its new
shape, by means of a hair straightening operation, with a wide-toothed
comb, with the back of a comb, by hand or with a brush.
This application may also be followed with a heating treatment,
10 especially using an iron.
The straightening of the hair may also be performed, totally or partly, using a heating iron at between 60 and 250°C and preferably between 120 and 230°C.
After the permanent deformation treatment method has been
15 performed, the keratinous fibres are preferably rinsed thoroughly,
generally with water. This can be done without any heat treatment after application of the reducing agent.
According to the invention, the treatment method is preferably a method of perming human keratinous fibres such as the hair. 20
The invention also relates to a composition comprising:
- one or more diacidic compounds as previously described ;
and
- one or more chemical oxidizing agents as previously
25 described.
Preferably, the composition according to the invention comprises a solvent as described above.
Preferably, the composition according to the invention
comprises one or more surfactant(s) as previously described.
30 The composition may also comprise any auxiliary ingredients
as previously described.
According to a preferred embodiment, the chemical oxidizing agents are present in the composition in an amount ranging from 0.5 to

21
12 %, preferably from 2 to 10 % by weight, and the diacid compounds
are present in an amount ranging from 0.1 to 15% by weight, more
preferably from 0.5 to 10% by weight, particularly from 0.8 to 8% by
weight, even better from 1 to 5% by weight, relative to the total
5 weight of composition.
The invention also relates to the use of the composition
described above, for the treatment of keratin fibers, in particular
human keratin fibers such as the hair, preferably for shaping and/or
10 styling said keratin fibers.
The following examples are given by way of illustration of the present invention and shall not be interpreted as limiting the scope.
15 EXAMPLES:
Example 1: Synthesis of the 8,11-dioxa-5,14-diazaoctadeca-2,16-dienedioic acid, 4,15-dioxo-, (2Z,16Z) - Compound 1
O O
U II H
H II II
20 O O
In a 500 ml three-necked flask equipped with a thermometer, a condenser, an argon inlet, a bubbler, an addition funnel and a magnetic stirrer, 18.6 grams of maleic anhydride (0.1897 mol) were added in
25 350 ml of dichloromethane.
14 grams of 3,6-dioxa-1,8-octadiamine (0.09446 mol) were then added dropwise while maintaining the temperature below 25 ° C. The reaction mixture was stirred at room temperature for 6 hours. The precipitate formed was filtered off and then dried under vacuum to
30 obtain 17 grams of a white powder.

22
Example 2: Synthesis of the 9,12,15-Trioxa-5,19-diazatricosa-2,21-dienedioic acid, 4,20-dioxo-, (2Z,21Z) – Compound 2

O

O OO

HO \=-" "N ^^ O' ^^ \^ "O ^^ N \=^ "OH
H H
5
In a 250 ml three-necked flask equipped with a thermometer, a condenser, an argon inlet, a bubbler, an addition funnel and a magnetic stirrer, 5 grams of 3,3'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))dipropan-1-amine (0.0227 mole) were added in 50 mL of chloroform. Small
10 amounts of 4.45 grams of maleic anhydride were then added in order
to maintain the temperature between 25°C. and 35°C. The reaction
mixture was kept under stirring at room temperature for 12 hours. The
evolution of the reaction was followed by thin layer chromatography
(10% MeOH in CHCl3 and 0.1mL triethylamine) and mass
15 spectrometry. The reaction mixture was then evaporated under reduced
pressure to give the expected product in the form of a white powder.
Example 3: Synthesis of the 2-butenoic acid, 4,4'-[dithiobis(2,1-ethanediylimino)]bis[4-oxo-, (Z,Z) – Compound 3

20

H

OO

OO

S ^ N \=/ OH
H

In a 500 ml three-necked flask equipped with a thermometer, a condenser, an argon inlet, a bubbler, an addition funnel and a magnetic
25 stirrer, 50 grams of cystamine hydrochloride (0.222 mol) were added
in 150 ml of dichloromethane. 74 ml of N, N-diisopropylethylamine (0.444 mol) were then added and the mixture was then stirred for 30 minutes. A solution containing 43.6 grams of maleic anhydride dissolved in 150 ml of dichloromethane was then added dropwise.
30 After the addition was complete, the mixture was stirred fo r 24 hours.

23
The precipitate formed was then filtered off and then washed with 300 ml of dichloromethane. It was then dried in vacuum to give 45 grams of a white powder.
5 Example 4: Synthesis of the 9,12-dioxa-5,16-diazaicosa-2,18-
dienedioic acid 4,17-dioxo (2Z,18Z) - Compound 4
O O
If fl H
O O
10 In a 500 ml three-necked flask equipped with a thermometer, a
condenser, an argon inlet, a bubbler, an addition funnel and a magnetic stirrer, 19.7 grams of maleic anhydride (0.2 mol) were added in 150 ml of dichloromethane. 18 ml of 1,10-diamino-7,7-dioxadecane (0.1 mol) were then added dropwise while maintaining the temperature below
15 25°C. The reaction mixture was kept under stirring at room
temperature for 24 hours. The precipitate formed was filtered off and then dried under vacuum to obtain 33 grams of a white powder.

24
Example 5:
The compositions containing the ingredients hereunder were
prepared, with all amounts expressed by percentages by weight of
5 active matter with regard to the total weight of each composition.
Reducing composition (A):

DIPROPYLENE GLYCOL 1,4
CETRIMONIUM CHLORIDE 1
AMMONIUM HYDROXIDE 1,5
PENTASODIUM PENTETATE 0,16
ETHANOLAMINE 1,5
AMMONIUM THIOGLYCOLATE 11,8
CETEARYL ALCOHOL 8
DIAMMONIUM DITHIODIGLYCOLATE 3,6
BEHENTRIMONIUM CHLORIDE 3,2
CETETH-2 3
CETYL PALMITATE 2
FRAGRANCE 0,6
WATER AQUA QS to 100
10
Composition (B1):

COMPOUND 2 4.8
MONOETHANOLAMINE 0.1
WATER QS to 100
15

25
Composition (B2):

LAURAMINE OXIDE 0,6
POLYQUATERNIUM-6 0,5
TETRASODIUM ETIDRONATE 0,06
SODIUM SALICYLATE 0,035
PHOSPHORIC ACID 0,25
HYDROGEN PEROXIDE 2,4
TETRASODIUM PYROPHOSPHATE 0,04
FRAGRANCE 0,4
WATER QS to 100
OLETH-20 0,8
COMPOUND 2 4.8
MONOETHANOLAMINE 0.1
Composition (C): 5
LAURAMINE OXIDE 0,65
POLYQUATERNIUM-6 0,5
TETRASODIUM ETIDRONATE 0,06
SODIUM SALICYLATE 0,035
PHOSPHORIC ACID 0,25
HYDROGEN PEROXIDE 2,4
TETRASODIUM PYROPHOSPHATE 0,04
FRAGRANCE 0,4
OLETH-20 0,8
WATER QS to 100
10

26
Protocols of example 5:
- Step 1 - Application of the reducing composition (A):
2 grams of the reducing composition A is applied to a 1 gram hair
5 lock. The composition is left on the hair lock for 15 minutes. The lock
of hair is then rinsed, dried, wrapped around a hair curler, and then
heated during 10 minutes at 80°C and more 15 minutes at 120°C.
- Method 1 (reference):
10 Firstly, the reducing composition (A) is applied onto the hair lock as
detailed in step 1 above.
Then, 2 grams of composition (C) is applied onto the hair lock. The
hair lock is left for 10 minutes, then the hair curler is removed and the
hair lock is rinsed. 15
- Method 2 (invention):
Firstly, the reducing composition (A) is applied onto the hair lock as detailed in step 1 above.
Secondly, 2 grams of the composition (B1) is applied onto the hair
20 lock and left on for 15 minutes.
Then, 2 grams of composition (C) is applied onto the hair lock. The hair lock is left for 10 minutes, then the hair curler is removed and the hair lock is rinsed.
25 - Method 3 (invention):
Firstly, the reducing composition (A) is applied onto the hair lock as
detailed in step 1 above.
Secondly, 2 grams of the composition (B2) is applied onto the hair
lock and left on for 10 minutes.
30 Then, the hair curler is removed and the hair lock is rinsed.
- Method 4 (invention):
Firstly, the reducing composition (A) is applied onto the hair lock as detailed in step 1 above.

27
Secondly, 2 grams of the composition (B1) is applied onto the hair lock and left on for 10 minutes.
Then, the hair curler is removed and the hair lock is ri nsed.
5 Results of example 5:
Table 1:
Number of loops Length of the lock (cm)
Step 1 only 3.5 21.9
Method 1 (reference) 4.2 18.5
Method 2 (invention) 4.4 18.6
Method 3 (invention) 4.2 18.8
Method 4 (invention) 4.2 20.5
Table 2:
Protein denaturation temperature (°C) Enthalpy of
denaturation
(J/g)
Untreated natural hair lock (control) 151.7 + 0.20 11.4+ 0.11
Method 1 (reference) 145.6 + 0.28 8.5+ 0.20
Method 2 (invention) 148.7 + 0.14 11.3+ 0.09
Method 3 (invention) 148.9 + 0.30 10.4+ 0.20
Method 4 (invention) 150.14 + 0.07 11.3 + 0.32
10 The hair locks treated with one of the methods according to the
invention show a hair-shaping effect similar to the reference hair lock (lock treated according to method 1).
The hair locks treated with one of the methods according to the
15 invention show a higher fiber quality in comparison to the reference
hair lock, a closer fiber quality in comparison to the untreated natural hair lock.

28
Analysis were carried out using Differential Scanning Calorimetry
(DSC) which monitors the heat changes associated with phase
transitions and chemical reactions. Difference in heat flow between
reference (pan) and sample (pan) is monitored against time and
5 temperature.
Example 6:
The compositions containing the ingredients hereunder were
prepared, with all amounts expressed by percentages by weight of
10 active matter with regard to the total weight of each composition.
Reducing composition (D):

AMMONIUM BICARBONATE 3,4
CETRIMONIUM CHLORIDE 0,046
PHENOXYETHANOL 0,01
AMMONIUM HYDROXIDE 0,6
GLYCERYL LAURATE 0,073
SODIUM BENZOATE 0,0073
AMMONIUM THIOGLYCOLATE 7,3
GLYCERIN 0,025
EDTA 0,1
COCAMIDOPROPYL BETAINE 0,35
ACETIC ACID 0,002
HEXADIMETHRINE CHLORIDE 0, 8
AMODIMETHICONE 0,6
TRIDECETH-15 0,04
TRIDECETH-3 0,04
SODIUM CHLORIDE 0,07
OLETH-20 0,4
FRAGRANCE PARFUM 0,3
WATER QS to 100

29
Composition (E):

COMPOUND 2 3.0
MONOETHANOLAMINE Qs pH = 3
WATER QS to 100
5
Composition (F):

LAURAMINE OXIDE 0,645
POLYQUATERNIUM-6 0,5
TETRASODIUM ETIDRONATE 0,06
BENZOPHENONE-4 0,01
SODIUM SALICYLATE 0,035
PHOSPHORIC ACID 0,255
HYDROGEN PEROXIDE 2,4
TETRASODIUM PYROPHOSPHATE 0,04
WATER QS to 100
10 Protocols of example 6:
- Step 1 - Application of the reducing composition (D):
2 grams of the reducing composition (D) is applied to a 1 gram hair lock. The composition is left on the hair lock for 15 minutes. The lock of hair is then rinsed, 15
- Method 5 (reference):
Firstly, the reducing composition (D) is applied onto the hair lock as detailed in step 1 in the example 6 above.
Then, 2 grams of composition (F) is applied onto the hair lock. The
20 hair lock is left for 5 minutes, then the hair curler is removed and the
hair lock is rinsed.

30
- Method 6 (Invention):
Firstly, the reducing composition (D) is applied onto the hair lock as
detailed in step 1 in the example 6 above.
5 Then, 2 grams of composition (F) and 3 grams of composition (E) are
sequentially applied onto the hair lock. The hair lock is left for 5 minutes. The hair curler is removed and the hair lock is rinsed.
Evaluations of example 6:
10 - Perm efficacy: Measured the diameter of the hair after the
described protocol, and obtained the perm efficacy calculated as:
“Perm Efficacy (%)” = the diameter of the roller (mm) / curl diameter
(mm) x 100
Higher value of the perm efficacy (%) shows the hair is curlier as the
15 consumer expected.
- Surface Friction: Placed the hair swatch and scanned it from root
to tip using the sensor to obtain the friction.
Smaller value shows the hair is smoother as the consumer expect s
20 [Measurement Equipment]: Manufacturer: Trinity Lab
Machine Name: Handy Rub Tester
- Combing tester for easiness of combing: Placed the wet or dry hair
swatch and combed the hair from root to tip using the sensor to obtain
25 the combing friction.
Smaller value shows the hair is “easy to comb” as the consumer expects.
[Measurement Equipment]: Manufacturer: Diastron
Machine Name: MTT175
30

-Tensile Strength: The machine pulled the single hair fiber by 20 mm/seconds until the hair was broken in order to obtain the results of Young modulus (Gpa) and Break load (MPa). Conducted the measurement for 24 fibers.
Higher value of them shows that the hair keeps original inner fiber structure, which means by healthier hair as the consumer expects.
[Measurement Equipment]: Manufacturer: Diastron
Machine Name: MTT688
Results of example 6:
Table 3: results of day application

Perm
efficacy
(%) Surface friction Combing
friction
at wet
[N] Combing
friction
at dry
[N] Tensile
strength:
Y-modulus
[Gpa] Tensile
strength:
Break
Load
[MPa]
Method 5 (reference) 50.2 0.295 3.86 0.82 0.80 1.40E+02
Method 6 (invention) 52.5 0.265 1.47 0.71 0.94 1.56E+02
Table 4: results of after 10 shampoos

Perm
efficacy
(%) Surface friction Combing
friction at
wet [N] Combing
friction at
dry[N]
Method 5 (reference) 46.7 0.280 4.59 1.70
Method 6 (invention) 48.4 0.250 2.31 1.11
The hair locks treated with one of the methods according to the invention have a higher fiber quality and are closer to the untreated natural lock of hair, compared to the reference hair lock. The results remain superior after 10 shampoos.

WE CLAIM

Method for shaping keratin fibers, comprising:
- a step (i) of applying onto the keratin fibers a composition (A) comprising one or more reducing agents ; then
5 - a step (ii) of applying onto the keratin fibers a composition (B)
comprising one or more diacidic compounds chosen from the compounds of formula (I) ; geometrical isomers thereof; optical isomers thereof ; salts thereof; and mixtures thereof:
HOOC-C(R2)=C(Ri)-C(0)-A-B-A-C(0)-C(Ri)=C(R2)-COOH (I)
in which:
-A represents an oxygen atom, a sulfur atom, or an -NH- group ; -B represents a linear or branched Ci-Cis hydrocarbon chain, optionally interrupted by one or more: o oxygen atoms, o sulfur atoms, o -NH- groups,
o -N(R')- groups wherein R' represents a linear or branched Ci-C4 alkyl group, optionally substituted with one or more hydroxy groups, and/or o -N+(R")(R'")- groups wherein R" and R'" represent, independently, a linear or branched C1-C4 alkyl group, optionally substituted with one or more hydroxy groups ; -Ri and R2 each represent, independently, a hydrogen atom, or a linear or branched C1-C3 alkyl group.
2. Method according to the preceding claim, characterized in
that the reducing agent(s) is(are) selected from thiol reducing agents,
non-thiol reducing agents, salts thereof, and mixtures thereof;
preferably from thiol reducing agents and salts thereof; and more
preferably from thioglycolic acid, thiolactic acid, cysteine,

cysteamine, homocysteine, glutathione, thioglycerol, thiomalic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiodiglycol, 2-mercaptoethanol, dithiothreitol, thioxanthine, thiosalicylic acid, thiodiglycolic acid, lipoic acid, N-acetylcysteine, and thioglycolic or thiolactic acid esters and amides, in particular glyceryl monothioglycolate, salts thereof, and mixtures of these compounds, more preferably from thioglycolic acid and salts thereof.
3. Method according to any one of the preceding claims, characterized in that the reducing agent(s) represents from 0.01 to 20% by weight, preferably from 0.01 to 15% by weight, more preferably from 0.1 to 10% by weight, and even more preferably from 1.0 to 10% by weight, relative to the total weight of composition (A).
4. Method according to any one of the preceding claims, characterized in that, in formula (I), A represents an oxygen atom or a -NH- group, and preferably a -NH- group.
5. Method according to any one of the preceding claims, characterized in that, in formula (I), B represents a linear or branched C1-C18, preferably C3-C18, more preferably linear C3-C12, hydrocarbon chain, optionally interrupted by one or more oxygen atoms, one or more sulfur atoms, and/or one or more -NH- groups.
6. Method according to any one of the preceding claims, characterized in that, in formula (I), Ri and R2 each represent, independently, a hydrogen atom or a methyl radical; and preferably Ri and R2 both represent a hydrogen atom.
7. Method according to any one of the preceding claims, characterized in that the diacidic compound(s) of formula (I) is(are) chosen from the following compounds (1) to (8):

HOOC-CH=CH-C(0)NH-(CH2CH20)2- (CH2)2-NHC(0)-CH=CH-COOH
(1)
HOOC -CH=CH-C(0)NH- CH2-(CH2CH20; )3-(CH2)3 -NHC(0)-CH=CH- -COOH
(2)
HOOC-CH=CH-C(0)NH-(CH2)2-S-S-(CH2)2-NHC(0)-CH=CH-COOH
(3)
HOOC -CH=CH-C(0)NH- CH2-(CH2CH20; )2-(CH2)3 -NHC(0)-CH=CH- -COOH
(4)
HOOC- -CH=CH -C(0)-0-(CH2)3
(5) -O-C(O)- CH=CH-COOH
HOOC- -CH=CH -C(0)-0-(CH2)4
(6) -O-C(O)- CH=CH-COOH
HOOC- -CH=CH -C(0)-0-(CH2)6
(7) -O-C(O)- CH=CH-COOH
HOOC- -CH=CH -C(0)-0-(CH2)8
(8) -O-C(O)- CH=CH-COOH
8. Method according to any one of the preceding claims,
characterized in that the diacidic compound(s) of formula (I) has(have)
the following (Z)/(Z) structure :
0 0 0 0
HO /=\ A A /=\ OH
R^ RJ RJ R^
9. Method according to any one of the preceding claims,
characterized in that the diacidic compound(s) represents from 0.1 to
15% by weight, preferably from 0.5 to 10% by weight, and more

preferably from 0.8 to 8% by weight, even better from 1 to 5% by weight, relative to the total weight of composition (B).
10. Method according to any one of the preceding claims, characterized in that it further comprises applying onto the fibers of one or more chemical oxidizing agents.
11. Method according to any one of the preceding claims, characterized in that the chemical oxidizing agent(s) is(are) present in composition (B), or in a separate composition (C) applied onto the fibers in a separate step (iii) carried out after step (ii).
12. Method according to claim 10 or 11, characterized in that the chemical oxidizing agent(s) is(are) chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates, peracids and enzymes oxidases (with their possible cofactors), such as peroxidases, 2-electron oxidoreductases such as uricases and 4-electron oxygenases, such as laccases; more preferably, the chemical oxidizing agent is hydrogen peroxide.
13. Method according to claim 10 or 11, characterized in that the total content of the chemical oxidizing agent(s) ranges from 0.05 to 30%) by weight, preferably from 0.1 to 20% by weight, relative to the total weight of composition (B) or composition (C).
14. Method according to any one of claims 1 to 9, wherein no chemical oxidizing agent is applied onto the fibers.
15. Composition comprising :
one or more diacidic compounds as defined in any one of
claims 1 to 8 ; and
one or more chemical oxidizing agents.

16. Composition according to the preceding claim, characterized in that the chemical oxidizing agent(s) is(are) chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates, peracids and enzymes oxidases (with their possible cofactors), such as peroxidases, 2-electron oxidoreductases such as uricases and 4-electron oxygenases, such as laccases; more preferably, the chemical oxidizing agent is hydrogen peroxide.
17. Composition according to claim 15 or 16, characterized in that the chemical oxidizing agents are present in an amount ranging from 0.5 to 12 %, preferably from 2 to 10 % by weight, relative to the total weight of composition.
18. Composition according to any one of claims 15 to 17, characterized in that the diacid compounds are present in an amount ranging from 0.1 to 15% by weight, more preferably from 0.5 to 10% by weight, particularly from 0.8 to 8% by weight, even better from 1 to 5% by weight, relative to the total weight of composition.
19. Use of the composition as defined in any one of claims 15 to 18 for the treatment of keratin fibers, in particular human keratin fibers such as the hair, preferably for shaping and/or styling said keratin fibers