U.S. patent application number 12/301900 was filed with the patent office on 2010-12-02 for method for straightening keratinous fibers using heating means and an aromatic compound.
Invention is credited to Philippe Barbarat, Gerard Malle.
Application Number | 20100300472 12/301900 |
Document ID | / |
Family ID | 37651067 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100300472 |
Kind Code |
A1 |
Malle; Gerard ; et
al. |
December 2, 2010 |
METHOD FOR STRAIGHTENING KERATINOUS FIBERS USING HEATING MEANS AND
AN AROMATIC COMPOUND
Abstract
The invention concerns a method for straightening keratinous
fibers including: (i) a step of applying on the keratinous fibers a
hair straightening composition containing at least one
polyhydroxylated aromatic compound, (ii) a step of increasing the
temperature of the keratinous fibers, using heating means, to a
temperature ranging between 110 and 250.degree. C.
Inventors: |
Malle; Gerard; (Villiers
S/Morin, FR) ; Barbarat; Philippe; (Bois-Colombes,
FR) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
37651067 |
Appl. No.: |
12/301900 |
Filed: |
May 23, 2007 |
PCT Filed: |
May 23, 2007 |
PCT NO: |
PCT/FR2007/000871 |
371 Date: |
August 19, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60814554 |
Jun 19, 2006 |
|
|
|
Current U.S.
Class: |
132/204 ;
132/206; 132/212; 424/70.2 |
Current CPC
Class: |
A61K 8/35 20130101; A61K
8/69 20130101; A61K 8/347 20130101; A61K 8/368 20130101; A61K 8/365
20130101; A61K 8/415 20130101; A61K 2800/24 20130101; A61K 8/42
20130101; A45D 7/06 20130101; A61Q 5/04 20130101 |
Class at
Publication: |
132/204 ;
424/70.2; 132/206; 132/212 |
International
Class: |
A45D 7/06 20060101
A45D007/06; A61K 8/34 20060101 A61K008/34; A61Q 5/04 20060101
A61Q005/04; A45D 7/04 20060101 A45D007/04; A45D 7/02 20060101
A45D007/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2006 |
FR |
0651910 |
Claims
1-11. (canceled)
12. A process for relaxing keratin fibers, comprising: applying to
the keratin fibers a hair-relaxing composition comprising at least
one polyhydroxylated aromatic compound, wherein the pH of said
hair-relaxing composition is less than or equal to 9, and heating
the keratin fibers to a temperature ranging from 110.degree. C. to
250.degree. C., wherein the polyhydroxylated aromatic compound is
not chosen from: 4,5-diamino-2,6-dihydroxypyrimidine,
2,4-dihydroxypyrimidine-5-carboxylic acid,
2,4-dihydroxy-6-methylpyrimidine, dihydroxyorotic acid, and
2,4,5-trihydroxypyrimidine.
13. A process according to claim 12, wherein said keratin fibers
are heated to a temperature ranging from 120.degree. C. to
220.degree. C.
14. A process according to claim 13, wherein said keratin fibers
are heated to a temperature ranging from 140.degree. C. to
220.degree. C.
15. A process according to claim 12, wherein the hair-relaxing
composition is applied to wet keratin fibers.
16. A process according to claim 12, wherein the keratin fibers are
partially predried.
17. A process according to claim 12, wherein the molar
concentration of the at least one polyhydroxylated aromatic
compound ranges from 1 to 8 M.
18. A process according to claim 17, wherein the molar
concentration of the at least one polyhydroxylated aromatic
compound ranges from 1 to 4 M.
19. A process according to claim 17, wherein the molar
concentration of the at least one polyhydroxylated aromatic
compound ranges from 1.5 to 3 M.
20. A process according to claim 12, wherein the pH of the
hair-relaxing composition is less than or equal to 7.
21. A process according to claim 12, wherein the at least one
polyhydroxylated aromatic compound corresponds to the formula (I):
##STR00004## wherein: R.sub.1, R.sub.2, R.sub.3, and R.sub.4, which
may be identical or different are chosen from: H, F, Cl, Br, OH,
OCH.sub.3, OEt, CHO, COCH.sub.3, COOH, CH.sub.2NH.sub.2,
CH.sub.2CH.sub.2NH.sub.2, CH.sub.2OH, CH.sub.2CH.sub.2OH,
CH.sub.2COCH.sub.3, CH.sub.2COOH, CH.sub.2CH.sub.2COOH,
CH.sub.2CONH.sub.2, CHOH--CH.sub.2OH, --CH(NH.sub.2)COOH,
NHCOCH.sub.3, COCH.sub.2CH.sub.3, CONH.sub.2, and a linear or
branched C.sub.1-C.sub.5 alkyl radical when the two OH radicals are
in a meta position and when R.sub.1, R.sub.2, and R.sub.3 represent
a hydrogen atom, R.sub.4 may also represent NH.sub.2, and the
stereoisomers, and organic or mineral salts thereof.
22. A process according to claim 21, wherein the compound of
formula (I) is chosen from: catechol, resorcinol, 4-methylcatechol,
3-methylcatechol, 2-methylresorcinol, 5-methylresorcinol,
4-methylresorcinol, pyrogallol, 1,2,4-trihydroxybenzene,
phloroglucinol, 3-fluorocatechol, 4-fluorocatechol,
4-fluororesorcinol, 2,3-dihydroxybenzaldehyde,
3,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde,
3,5-dihydroxybenzaldehyde, 4-ethylcatechol, 4-ethylresorcinol,
2,5-dimethylresorcinol, 4,5-dimethylresorcinol,
2,4-dimethyl-1,3-benzenediol, 3,4-dihydroxybenzylamine,
3,5-dihydroxybenzylamine, 3-methoxycatechol, 5-methylpyrogallol,
3,4-dihydroxybenzyl alcohol, 5-methoxyresorcinol,
2,4,6-trihydroxytoluene, 3,5-dihydroxybenzyl alcohol,
2-methoxyresorcinol, 5-methylpyrogallol, 4-methoxyresorcinol,
3,5-dihydroxytoluene monohydrate, 4-chlorocatechol,
3-chlorocatechol, 4-chlororesorcinol, 2-chlororesorcinol,
3',4'-dihydroxyacetophenone, 2',3'-dihydroxyacetophenone,
2',6'-dihydroxyacetophenone, 2',4'-dihydroxyacetophenone,
3',5'-dihydroxyacetophenone, 2,6-dihydroxy-4-methylbenzaldehyde,
3-isopropylcatechol, 4-isopropylcatechol, 4-propylresorcinol,
2,4-dihydroxy-1,3,5-trimethylbenzene, 3,4-dihydroxybenzamide,
3,5-dihydroxybenzamide, 2,6-dihydroxybenzamide,
2,4-dihydroxybenzamide, 3-hydroxytyramine, 2,3-dihydroxybenzoic
acid, 3,4-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid,
2,6-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid,
2,3,4-trihydroxybenzaldehyde, 2,4,6-trihydroxybenzaldehyde,
3,4,5-trihydroxybenzaldehyde, 2,4,5-trihydroxybenzaldehyde,
2-(3,4-dihydroxyphenyl)ethanol,
2,4,6-trihydroxy-1,3-dimethylbenzene, 2,6-dihydroxy-4-methylbenzyl
alcohol, 2-fluoro-3,4-dihydroxybenzaldehyde,
3,4-dihydroxy-6-fluorobenzaldehyde, 2-methoxyphloroglucinol,
3,5-dihydroxyanisole hydrate, 4-aminoresorcinol hydrochloride,
2-aminoresorcinol hydrochloride, 5-aminobenzene-1,3-diol
hydrochloride, phloroglucinol dihydrate,
3',4'-dihydroxypropiophenone, 3,4-dihydroxyphenylacetone,
(2,3-dihydroxyphenyl)acetone, 2',4'-dihydroxypropiophenone,
2',4'-dihydroxy-3'-methylacetophenone,
(2,4-dihydroxyphenyl)acetone, (3,5-dihydroxyphenyl)acetone,
2,6-dihydroxy-4'-methylacetophenone, 4-tert-butylcatechol,
4-N-butylresorcinol, 2,4-diethyl-1,3-benzenediol,
3,4-dihydroxyphenylacetamide, 3-hydroxyacetaminophen,
2',3',4'-trihydroxyacetophenone, 3,4-dihydroxyphenylacetic acid,
2,3-dihydroxy-4-methoxybenzaldehyde,
3,4-dihydroxy-5-methoxybenzaldehyde,
2',3',4'-trihydroxyacetophenone, 2',4',6'-trihydroxyacetophenone,
3,5-dihydroxy-4-methylbenzoic acid, 2,6-dihydroxy-4-methylbenzoic
acid, 2,4-dihydroxy-6-methylbenzoic acid, 3,5-dihydroxyphenylacetic
acid, 2-ethyl-5-methoxybenzene-1,3-diol, 3,4,5-trihydroxybenzamide,
4-amino-3,5-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid,
2,3,4-trihydroxybenzoic acid, gallic acid, 2,4,6-trihydroxybenzoic
acid, 3,4-dihydroxyphenyl glycol,
1,2-dihydroxy-4,5-dimethoxybenzene, 3,5-dihydroxyacetophenone
monohydrate, 3,4-dihydroxybenzoic acid monohydrate,
3,4,5-trihydroxybenzaldehyde, hexahydroxybenzene,
3,5-dihydroxybenzylamine hydrochloride, 4,6-diaminoresorcinol
hydrochloride, 4,5-dichlorocatechol, 3,5-dichlorocatechol,
4,6-dichlororesorcinol, 2',4'-dihydroxy-3'-methylpropiophenone,
1-(3-ethyl-2,6-dihydroxyphenyl)ethan-1-one,
3-(3,4-dihydroxyphenyl)propionic acid,
(2,3,4-trihydroxyphenyl)acetone, (2,4,5-trihydroxyphenyl)acetone,
(3,4,5-trihydroxyphenyl)acetone,
2',6'-dihydroxy-4'-methoxyacetophenone,
1-(2,6-dihydroxy-3-methoxyphenyl)ethan-1-one,
3(2,4-dihydroxyphenylpropionic acid,
2,4-dihydroxy-3,6-dimethylbenzoic acid,
(2,3,4-trihydroxyphenyl)acetone, (2,4,5-trihydroxyphenyl)acetone,
(2,4,6-trihydroxyphenyl)acetone, (3,4,5-trihydroxyphenyl)acetone,
3,4-dihydroxymandelic acid, 5-hydroxyisovanillic acid,
3,4,5-trihydroxybenzamide hydrate, and 4-bromocatechol, and the
stereoisomers and organic or mineral salts thereof.
23. A process according to claim 21, wherein the compound of
formula (I) is chosen from: resorcinol, 2-methylresorcinol,
5-methylresorcinol, 4-methylresorcinol, pyrogallol,
1,2,4-trihydroxybenzene, 4-ethyl resorcinol,
2,5-dimethylresorcinol, 4,5-dimethylresorcinol,
2,4-dimethyl-1,3-benzenediol, 3,4-dihydroxybenzylamine,
3,5-dihydroxybenzylamine, 5-methylpyrogallol, 3,4-dihydroxybenzyl
alcohol, 5-methoxyresorcinol, 2,4,6-trihydroxytoluene,
3,5-dihydroxybenzyl alcohol, 2-methoxyresorcinol,
5-methylpyrogallol, 4-methoxyresorcinol, 3,5-dihydroxytoluene
monohydrate, 4-propylresorcinol,
2,4-dihydroxy-1,3,5-trimethylbenzene, 3,4-dihydroxybenzamide,
3,5-dihydroxybenzamide, 2,6-dihydroxybenzamide,
2,4-dihydroxybenzamide, 3-hydroxytyramine, 2,3-dihydroxybenzoic
acid, 3,4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid,
3,5-dihydroxybenzoic acid, 2-(3,4-dihydroxyphenyl)ethanol,
2,4,6-trihydroxy-1,3-dimethylbenzene, 2,6-dihydroxy-4-methylbenzyl
alcohol, 2-methoxyphloroglucinol, 3,5-dihydroxyanisole hydrate,
4-aminoresorcinol hydrochloride, 2-aminoresorcinol hydrochloride,
5-aminobenzene-1,3-diol hydrochloride, phloroglucinol dihydrate,
2,4-diethyl-1,3-benzenediol, 3,4-dihydroxyphenylacetamide,
3,4-dihydroxyphenylacetic acid, 3,5-dihydroxy-4-methylbenzoic acid,
2,6-dihydroxy-4-methylbenzoic acid, 2,4-dihydroxy-6-methylbenzoic
acid, 3,5-dihydroxyphenylacetic acid,
2-ethyl-5-methoxybenzene-1,3-diol, 3,4,5-trihydroxybenzamide,
4-amino-3,5-dihydroxybenzoic acid, 3,4-trihydroxybenzoic acid,
gallic acid, 2,4,6-trihydroxybenzoic acid, DL-3,4-dihydroxyphenyl
glycol, 1,2-dihydroxy-4,5-dimethoxybenzene, 3,4-dihydroxybenzoic
acid monohydrate, hexahydroxybenzene, 3,5-dihydroxybenzylamine
hydrochloride, sodium .gamma.-resorcylate, sodium
.beta.-resorcylate, 4,6-diaminoresorcinol hydrochloride,
3-(3,4-dihydroxyphenyl)propionic acid,
2,4-dihydroxy-3,6-dimethylbenzoic acid, DL-3,4-dihydroxymandelic
acid, hydroxyisovanillic acid, 3,4,5-trihydroxybenzamide acid
hydrate, and gallic acid monohydrate, and the stereoisomers and
organic or mineral salts thereof.
24. A process for relaxing keratin fibers, comprising: applying to
the keratin fibers a hair-relaxing composition comprising
resorcinol, wherein the pH of said hair-relaxing composition is
less than or equal to 9, and heating the keratin fibers to a
temperature ranging from 110.degree. C. to 250.degree. C.
25. A kit comprising at least: one heating apparatus that provides
a temperature ranging from 110.degree. C. to 250.degree. C., at
least one hair-relaxing composition comprising at least one
polyhydroxylated aromatic compound, wherein the pH of said
hair-relaxing composition is less than or equal to 9, and wherein
the polyhydroxylated aromatic compound is not chosen from:
4,5-diamino-2,6-dihydroxypyrimidine, and
2,4-dihydroxypyrimidine-5-carboxylic acid.
26. A kit according to claim 25, wherein the at least one
hair-relaxing composition comprises at least one polyhydroxylated
aromatic compound chosen from: catechol, resorcinol,
4-methylcatechol, 3-methylcatechol, 2-methylresorcinol,
5-methylresorcinol, 4-methylresorcinol, pyrogallol,
1,2,4-trihydroxybenzene, phloroglucinol, 3-fluorocatechol,
4-fluorocatechol, 4-fluororesorcinol, 2,3-dihydroxybenzaldehyde,
3,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde,
3,5-dihydroxybenzaldehyde, 4-ethylcatechol, 4-ethylresorcinol,
2,5-dimethylresorcinol, 4,5-dimethylresorcinol,
2,4-dimethyl-1,3-benzenediol, 3,4-dihydroxybenzylamine,
3,5-dihydroxybenzylamine, 3-methoxycatechol, 5-methylpyrogallol,
3,4-dihydroxybenzyl alcohol, 5-methoxyresorcinol,
2,4,6-trihydroxytoluene, 3,5-dihydroxybenzyl alcohol,
2-methoxyresorcinol, 5-methylpyrogallol, 4-methoxyresorcinol,
3,5-dihydroxytoluene monohydrate, 4-chlorocatechol,
3-chlorocatechol, 4-chlororesorcinol, 2-chlororesorcinol,
3',4'-dihydroxyacetophenone, 2',3'-dihydroxyacetophenone,
2',6'-dihydroxyacetophenone, 2',4'-dihydroxyacetophenone,
3',5'-dihydroxyacetophenone, 2,6-dihydroxy-4-methylbenzaldehyde,
3-isopropylcatechol, 4-isopropylcatechol, 4-propylresorcinol,
2,4-dihydroxy-1,3,5-trimethylbenzene, 3,4-dihydroxybenzamide,
3,5-dihydroxybenzamide, 2,6-dihydroxybenzamide,
2,4-dihydroxybenzamide, 3-hydroxytyramine, 2,3-dihydroxybenzoic
acid, 3,4-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid,
2,6-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid,
2,3,4-trihydroxybenzaldehyde, 2,4,6-trihydroxybenzaldehyde,
3,4,5-trihydroxybenzaldehyde, 2,4,5-trihydroxybenzaldehyde,
2-(3,4-dihydroxyphenyl)ethanol,
2,4,6-trihydroxy-1,3-dimethylbenzene, 2,6-dihydroxy-4-methylbenzyl
alcohol, 2-fluoro-3,4-dihydroxybenzaldehyde,
3,4-dihydroxy-6-fluorobenzaldehyde, 2-methoxyphloroglucinol,
3,5-dihydroxyanisole hydrate, 4-aminoresorcinol hydrochloride,
2-aminoresorcinol hydrochloride, 5-aminobenzene-1,3-diol
hydrochloride, phloroglucinol dihydrate,
3',4'-dihydroxypropiophenone, 3,4-dihydroxyphenylacetone,
(2,3-dihydroxyphenyl)acetone, 2',4'-dihydroxypropiophenone,
2',4'-dihydroxy-3'-methylacetophenone,
(2,4-dihydroxyphenyl)acetone, (3,5-dihydroxyphenyl)acetone,
2,6-dihydroxy-4'-methylacetophenone, 4-tert-butylcatechol,
4-N-butylresorcinol, 2,4-diethyl-1,3-benzenediol,
3,4-dihydroxyphenylacetamide, 3-hydroxyacetaminophen,
2',3',4'-trihydroxyacetophenone, 3,4-dihydroxyphenylacetic acid,
2,3-dihydroxy-4-methoxybenzaldehyde,
3,4-dihydroxy-5-methoxybenzaldehyde,
2',3',4'-trihydroxyacetophenone, 2',4',6'-trihydroxyacetophenone,
3,5-dihydroxy-4-methylbenzoic acid, 2,6-dihydroxy-4-methylbenzoic
acid, 2,4-dihydroxy-6-methylbenzoic acid, 3,5-dihydroxyphenylacetic
acid, 2-ethyl-5-methoxybenzene-1,3-diol, 3,4,5-trihydroxybenzamide,
4-amino-3,5-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid,
2,3,4-trihydroxybenzoic acid, gallic acid, 2,4,6-trihydroxybenzoic
acid, 3,4-dihydroxyphenyl glycol,
1,2-dihydroxy-4,5-dimethoxybenzene, 3,5-dihydroxyacetophenone
monohydrate, 3,4-dihydroxybenzoic acid monohydrate,
3,4,5-trihydroxybenzaldehyde, hexahydroxybenzene,
3,5-dihydroxybenzylamine hydrochloride, 4,6-diaminoresorcinol
hydrochloride, 4,5-dichlorocatechol, 3,5-dichlorocatechol,
4,6-dichlororesorcinol, 2',4'-dihydroxy-3'-methylpropiophenone,
1-(3-ethyl-2,6-dihydroxyphenyl)ethan-1-one,
3-(3,4-dihydroxyphenyl)propionic acid,
(2,3,4-trihydroxyphenyl)acetone, (2,4,5-trihydroxyphenyl)acetone,
(3,4,5-trihydroxyphenyl)acetone,
2',6'-dihydroxy-4'-methoxyacetophenone,
1-(2,6-dihydroxy-3-methoxyphenyl)ethan-1-one,
3(2,4-dihydroxyphenylpropionic acid,
2,4-dihydroxy-3,6-dimethylbenzoic acid,
(2,3,4-trihydroxyphenyl)acetone, (2,4,5-trihydroxyphenyl)acetone,
(2,4,6-trihydroxyphenyl)acetone, (3,4,5-trihydroxyphenyl)acetone,
3,4-dihydroxymandelic acid, 5-hydroxyisovanillic acid,
3,4,5-trihydroxybenzamide hydrate, and 4-bromocatechol, and the
stereoisomers and organic or mineral salts thereof.
Description
[0001] The invention relates to a process for relaxing keratin
fibres with a heating means and at least one polyhydroxylated
aromatic compound.
[0002] The relaxing process according to the invention is performed
without using any reducing agent or lanthionizing agent. It does
not include any reducing or lanthionization step.
[0003] According to the invention, the term "keratin fibres" means
fibres of human or animal origin such as head hair, bodily hair,
the eyelashes, wool, angora, cashmere or fur. Although the
invention is not limited to particular keratin fibres, reference
will nevertheless be made more particularly to head hair.
[0004] According to the invention, the term "relaxing" covers the
relaxing, straightening or uncurling of Caucasian or African
hair.
[0005] The term "heating means" means any means for heating keratin
fibres to a temperature of at least 110.degree. C., such as heating
irons, for example flat or round irons, microwave generators or
sources of infrared radiation.
[0006] Two techniques are used for permanently reshaping the hair.
They are based on cleavage of the disulfide covalent bonds present
in keratin (cystine): [0007] the first consists, in a first stage,
in performing this opening of the disulfide bonds using a
composition containing a reducing agent, and then, after having
preferably rinsed the hair, in reconstituting the said disulfide
bonds in a second stage, by applying to the hair, which has been
placed under tension beforehand with rollers or the like or shaped
or straightened out by other means, an oxidizing composition also
known as a fixer, so as to give the head of hair the desired shape.
This technique makes it possible either to make the hair wavy or to
relax it, uncurl it or straighten it out; [0008] the second
consists in performing a "lanthionization" operation using a
composition containing a base belonging to the hydroxide family.
This leads to replacement of the disulfide bonds (--CH2-S--S--CH2-)
with lanthionine bonds (--CH2-S--CH2-).
[0009] This lanthionization operation involves two consecutive
chemical reactions: [0010] the first reaction consists of a
beta-elimination on cystine brought about by a hydroxide ion,
leading to the cleavage of this bond and to the formation of
dehydroalanine:
[0010] ##STR00001## [0011] the second reaction is a reaction of
dehydroalanine with a thiol group. Specifically, the double bond of
the dehydroalanine formed is a reactive double bond. It can react
with the thiol group of the cysteine residue that has been released
to form a new bond referred as a lanthionine bridge or bond or
residue.
##STR00002##
[0012] Relative to the first technique using a reducing agent, this
lanthionization technique does not require a fixing step, since the
formation of the lanthionine bridges is irreversible. It is thus
performed in a single step and makes it possible either to make the
hair wavy, or to relax it, uncurl or straighten it out. However, it
is mainly used for relaxing naturally curly hair.
[0013] For the first technique, the reducing compositions generally
used for the first step of a permanent-waving or hair-relaxing
operation contain thiols, sulfites or bisulfites as reducing agent.
These agents are generally used in essentially aqueous medium at
concentrations of between 0.5 and 1 M to obtain good opening of the
disulfide bonds. Among the thiols, those commonly used are
thioglycolic acid, cysteamine, glyceryl monothioglycolate,
thiolactic acid and cysteine. Thioglycolic acid is particularly
efficient at reducing the disulfide bonds of keratin at alkaline
pH, especially in the form of ammonium thioglycolate, and
constitutes the product most frequently used in permanent waving
("hair waving"). It has been found, however, that thioglycolic acid
must be used in sufficiently basic medium (in practice at a pH of
between 8.5 and 9.5) if curling of satisfactory intensity is to be
obtained. Besides the drawback of releasing an unpleasant odour
requiring the use of more or less efficient fragrances to mask the
odours, the use of a thiol at alkaline pH also results in
degradation of the fibre and most particularly in impairment of
artificial colorations.
[0014] Sulfites or bisulfites are mainly used for relaxing the
hair. They have drawbacks similar to those of thiols, with lower
efficacy.
[0015] Thiols and sulfites (or bisulfites) also have the drawback
of having poor stability in aqueous solution.
[0016] In general, the durability of the reshaping effects obtained
with thiols and sulfites by reduction of disulfides following by
fixing is judged to be very much lower than that which may be
obtained via the lanthionization technique.
[0017] For the second technique, the compositions generally used to
perform lanthionization contain as base a hydroxide such as sodium
hydroxide, guanidinium hydroxide or lithium hydroxide. These
lanthionization active agents, which allow opening of the disulfide
bonds via a beta-elimination mechanism, are generally used as a
water-oil emulsion at concentrations of between 0.4 and 0.6 M, by
leaving them to act generally for 10 to 15 minutes at room
temperature. Sodium hydroxide remains the agent most frequently
used. Guanidinium hydroxide is now the preferred compound for many
compositions. These two hydroxides, sodium hydroxide and
guanidinium hydroxide, are the two main agents used for the
relaxing or uncurling of naturally curly hair. They have several
advantages over ammonium thioglycolate and sulfites, in particular
the absence of unpleasant odour, the fact that only one operating
step is required (shorter treatment time) and much greater
durability and efficacy of reshaping of the hair.
[0018] However, these hydroxides have the major drawback of being
caustic. This causticity affects the scalp by causing irritation,
which is occasionally severe. This may be partially remedied by
applying beforehand to the scalp fatty protective cream often
referred to as a "base" or "base cream", the word "base" in this
case not having the meaning of a basic agent in the chemical sense.
When the protective cream is combined with the hydroxide in a
single composition, it is generally referred to as "no-base", as
opposed to the above name. This "no-base" technique is
preferred.
[0019] The causticity of hydroxides also affects the state of the
hair by firstly giving it a coarse feel and secondly making it much
more brittle, this brittleness possibly going as far as crumbling
or breaking or even dissolution of the hair if the treatment is
prolonged. In certain cases, hydroxides also cause decoloration of
the natural colour of the hair.
[0020] Formulations containing sodium hydroxide are generally
referred to as "lye relaxers" and those not containing it are
referred as "no-lye relaxers".
[0021] The main relaxing formulations known as "no-lye" relaxers
use guanidinium hydroxide. Since guanidinium hydroxide is unstable,
it is generated at the time of use by mixing guanidinium carbonate
and a source of sparingly soluble hydroxide such as calcium
hydroxide. The reaction between these two compounds leads to the
formation of guanidinium hydroxide and calcium carbonate, which
precipitates in the composition. The presence of this precipitate
makes the final rinsing of the hair much more difficult and leaves
mineral particles on the hair and the scalp, which give it a coarse
feel and an unaesthetic appearance resembling dandruff. The recent
success of guanidinium hydroxide ("no-lye") over sodium hydroxide
("lye") appears to arise from better relaxing efficacy and better
skin tolerance. However, these techniques using bases of the
hydroxide family remain very aggressive to the hair and the scalp
and require very strict control of the duration of application to
avoid excessive irritation and impairment of the hair that may go
as far as breakage. This aggressiveness arising from the causticity
of hydroxides is justification for not using these hair
lanthionization compositions for permanent waving (hair waving),
but solely for hair straightening or hair relaxing.
[0022] Furthermore, hydroxides are known to be good agents for
hydrolysing amide functions (cf. for example March's Advanced
Organic Chemistry, 5th edition, Wiley Interscience, New York,
"Hydrolysis of Amides" page 474 et seq.), which thus lead to
cleavage of peptide bonds by direct nucleophilic attack. It is thus
probable that the observed impairments of the hair and of keratin
materials in the broad sense are largely due to partial hydrolysis
of the amide bonds of keratin.
[0023] There is thus a real need for relaxing compositions that are
markedly less aggressive to the hair.
[0024] Various studies have been conducted in order to overcome
both the drawbacks of reducing agents (first technique) and/or
those of hydroxides (second technique).
[0025] Thus, many reducing agents have been proposed to replace
thioglycolic acid, but thioglycolic acid in the form of ammonium
thioglycolate remains both the reference compound and the compound
most widely used in cosmetic formulations, not only for shaping but
also for straightening the hair.
[0026] It has also been proposed in numerous patents to combine
common reducing agents (thiols, sulfites or bisulfites) with urea
or alkyl ureas to reduce the irritation and damage caused to the
hair, not only for shaping but also for relaxing. Mention will be
made, for example, of: [0027] patent application CA 1315204, which
describes a composition containing ammonium thioglycolate
(5.5-11.5%) and urea or a monoalkyl urea (1-3%) for shaping the
hair, [0028] patent application U.S. Pat. No. 3,847,165, which
describes a composition containing ammonium thioglycolate (1.2-1.4
M) and urea (2.0-2.7 M) for shaping the hair at an acidic pH,
[0029] patent application NL 6410355, which describes a composition
containing a sulfite (0.8-1.5 M) and urea (0.6-3.0 M) for shaping
and relaxing the hair, [0030] patent application JP 2000/229 819,
which describes a composition containing a sulfite or bisulfite
(0.5-15%), urea (0.5-15%) and an alcohol (ethanol and/or
isopropanol, 1-30%) for shaping and relaxing the hair.
[0031] It has also been proposed in numerous patents to combine
hydroxides, serving as lanthionization active agent, with certain
additives generally serving to protect the hair. Mention will be
made, for example, of: [0032] patent application WO 2002/003 937,
which describes a composition containing C.sub.3-C.sub.5
monosaccharides, [0033] patent application WO 2001/064 171, which
describes a composition containing complexing agents, [0034] patent
U.S. Pat. No. 5,641,477, which describes a composition containing a
hydrogenated starch hydrolysate, [0035] patent application WO
02/085 317, which describes a composition containing organic
nucleophiles that react during the second step with the
dehydroalanine formed with hydroxides, to give new bridges.
[0036] Although all these proposals lead to more or less pronounced
improvements, they are not able to sufficiently reduce the damage
associated with the very causticity of hydroxides.
[0037] As indicated previously, the use of reducing agents leads to
poor durability of the relaxing or straightening of the hair and
the use of hydroxides, on account of their causticity, limits their
use in the field of hair relaxing.
[0038] The use of resorcinol at a concentration of 40% and at a pH
of 7 for relaxing the hair has been reported by M. Wong et al.: M.
Wong, G. Vis-surel, and J. Epps J. Soc. Cosmet. Chem. (1994), 45,
347-352. However, the tests that we have performed under these
conditions on naturally curly African hair do not relax it, but
lead, at the very best, to slight uncurling.
[0039] After considerable studies, it has now been discovered,
entirely surprisingly and unexpectedly, that hair can be durably
relaxed by combining the action of a polyhydroxylated aromatic
compound and of a means of heating to a temperature above
110.degree. C. Excellent results in terms of relaxing, cosmetic
properties of the hair and fibre integrity are thus obtained.
[0040] Without being bound by theory, the Applicant considers that
there is a combined action, on the keratin fibres, of a
polyhydroxylated aromatic compound and of a heating means, which
allows the fibres to be efficiently and durably relaxed.
[0041] The Applicant has found that it is possible to overcome the
drawbacks of the prior art and to satisfy the abovementioned
objectives by performing a process for relaxing keratin fibres,
comprising: [0042] a step of applying to the keratin fibres a
hair-relaxing composition containing at least one polyhydroxylated
aromatic compound, the pH of the composition being less than or
equal to 9, [0043] a step of raising the temperature of the keratin
fibres, using a heating means, to a temperature of between 110 and
250.degree. C.,
[0044] the polyhydroxylated aromatic compound not being chosen
from: [0045] 4,5-diamino-2,6-dihydroxypyrimidine, and [0046]
2,4-dihydroxypyrimidine-5-carboxylic acid.
[0047] Thus the invention relates to a process for relaxing keratin
fibres, comprising: [0048] a step of applying to the keratin fibres
a hair-relaxing composition containing at least one
polyhydroxylated aromatic compound, the pH of the composition being
less than or equal to 9, [0049] and then a step of raising the
temperature of the keratin fibres, using a heating means, to a
temperature of between 110 and 250.degree. C.,
[0050] the polyhydroxylated aromatic compound not being chosen
from: [0051] 4,5-diamino-2,6-dihydroxypyrimidine, [0052]
2,4-dihydroxypyrimidine-5-carboxylic acid, [0053]
2,4-dihydroxy-6-methylpyrimidine, [0054] dihydroxyorotic acid, and
[0055] 2,4,5-trihydroxypyrimidine.
[0056] Advantageously, the temperature is raised using a heating
means to a temperature of between 120.degree. C. and 220.degree. C.
and more advantageously between 140.degree. C. and 220.degree.
C.
[0057] Preferably, the said composition is applied to wet keratin
fibres.
[0058] A step intended to remove the excess composition, for
example using a towel, may also be introduced between the step of
applying the composition and the step of raising the
temperature.
[0059] Definition of the polyhydroxylated aromatic compounds of
general formula (I):
##STR00003##
in which: [0060] R1, R2, R3 and R4 represent, independently of each
other: [0061] H, F, Cl, Br, OH, OCH.sub.3, OEt, CHO, COCH.sub.3,
COOH, CH.sub.2NH.sub.2, CH.sub.2CH.sub.2NH.sub.2, CH.sub.2OH,
CH.sub.2CH.sub.2OH, CH.sub.2COCH.sub.3, CH.sub.2COOH,
CH.sub.2CH.sub.2COOH, CH.sub.2CONH.sub.2, CHOH--CH.sub.2OH,
--CH(NH.sub.2)COOH, NHCOCH.sub.3, COCH.sub.2CH.sub.3, CONH.sub.2
[0062] or alternatively a linear or branched C.sub.1-C.sub.5 alkyl
radical when the two OH radicals are in a meta position and when
R1, R2 and R3 represent a hydrogen atom, R4 may also represent
NH.sub.2, and the stereoisomers, organic or mineral salts and
solvates thereof.
Preferred Compounds of Formula (I):
[0062] [0063] catechol [0064] resorcinol [0065] 4-methylcatechol
[0066] 3-methylcatechol [0067] 2-methylresorcinol [0068]
5-methylresorcinol [0069] 4-methylresorcinol [0070] pyrogallol
[0071] 1,2,4-trihydroxybenzene [0072] phloroglucinol [0073]
3-fluorocatechol [0074] 4-fluorocatechol [0075] 4-fluororesorcinol
[0076] 2,3-dihydroxybenzaldehyde [0077] 3,4-dihydroxybenzaldehyde
[0078] 2,4-dihydroxybenzaldehyde [0079] 3,5-dihydroxybenzaldehyde
[0080] 4-ethylcatechol [0081] 4-ethyl resorcinol [0082]
2,5-dimethylresorcinol [0083] 4,5-dimethylresorcinol [0084]
2,4-dimethyl-1,3-benzenediol [0085] 3,4-dihydroxybenzylamine [0086]
3,5-dihydroxybenzylamine [0087] 3-methoxycatechol [0088]
5-methylpyrogallol [0089] 3,4-dihydroxybenzyl alcohol [0090]
5-methoxyresorcinol [0091] 2,4,6-trihydroxytoluene [0092]
3,5-dihydroxybenzyl alcohol [0093] 2-methoxyresorcinol [0094]
5-methylpyrogallol [0095] 4-methoxyresorcinol [0096]
3,5-dihydroxytoluene monohydrate [0097] 4-chlorocatechol [0098]
3-chlorocatechol [0099] 4-chlororesorcinol [0100]
2-chlororesorcinol [0101] 3',4'-dihydroxyacetophenone [0102]
2',3'-dihydroxyacetophenone [0103] 2',6'-dihydroxyacetophenone
[0104] 2',4'-dihydroxyacetophenone [0105]
3',5'-dihydroxyacetophenone [0106]
2,6-dihydroxy-4-methylbenzaldehyde [0107] 3-isopropylcatechol
[0108] 4-isopropylcatechol [0109] 4-propylresorcinol [0110]
2,4-dihydroxy-1,3,5-trimethylbenzene [0111] 3,4-dihydroxybenzamide
[0112] 3,5-dihydroxybenzamide [0113] 2,6-dihydroxybenzamide [0114]
2,4-dihydroxybenzamide [0115] 3-hydroxytyramine [0116]
2,3-dihydroxybenzoic acid [0117] 3,4-dihydroxybenzoic acid [0118]
2,4-dihydroxybenzoic acid [0119] 2,6-dihydroxybenzoic acid [0120]
3,5-dihydroxybenzoic acid [0121] 2,3,4-trihydroxybenzaldehyde
[0122] 2,4,6-trihydroxybenzaldehyde [0123]
3,4,5-trihydroxybenzaldehyde [0124] 2,4,5-trihydroxybenzaldehyde
[0125] 2-(3,4-dihydroxyphenyl)ethanol [0126]
2,4,6-trihydroxy-1,3-dimethylbenzene [0127]
2,6-dihydroxy-4-methylbenzyl alcohol [0128]
2-fluoro-3,4-dihydroxybenzaldehyde [0129]
3,4-dihydroxy-6-fluorobenzaldehyde [0130] 2-methoxyphloroglucinol
[0131] 3,5-dihydroxyanisole hydrate [0132] 4-aminoresorcinol
hydrochloride [0133] 2-aminoresorcinol hydrochloride [0134]
5-aminobenzene-1,3-diol hydrochloride [0135] phloroglucinol
dihydrate [0136] 3',4'-dihydroxypropiophenone [0137]
3,4-dihydroxyphenylacetone [0138] (2,3-dihydroxyphenyl)acetone
[0139] 2',4'-dihydroxypropiophenone [0140]
2',4'-dihydroxy-3'-methylacetophenone [0141]
(2,4-dihydroxyphenyl)acetone [0142] (3,5-dihydroxyphenyl)acetone
[0143] 2,6-dihydroxy-4'-methylacetophenone [0144]
4-tert-butylcatechol [0145] 4-N-butylresorcinol [0146]
2,4-diethyl-1,3-benzenediol [0147] 3,4-dihydroxyphenylacetamide
[0148] 3-hydroxyacetaminophen [0149]
2',3',4'-trihydroxyacetophenone [0150] 3,4-dihydroxyphenylacetic
acid [0151] 2,3-dihydroxy-4-methoxybenzaldehyde [0152]
3,4-dihydroxy-5-methoxybenzaldehyde [0153]
2',3',4'-trihydroxyacetophenone [0154]
2',4',6'-trihydroxyacetophenone [0155]
3,5-dihydroxy-4-methylbenzoic acid [0156]
2,6-dihydroxy-4-methylbenzoic acid [0157]
2,4-dihydroxy-6-methylbenzoic acid [0158] 3,5-dihydroxyphenylacetic
acid [0159] 2-ethyl-5-methoxybenzene-1,3-diol [0160]
3,4,5-trihydroxybenzamide [0161] 4-amino-3,5-dihydroxybenzoic acid
[0162] 2,3,4-trihydroxybenzoic acid [0163] 2,3,4-trihydroxybenzoic
acid [0164] gallic acid [0165] 2,4,6-trihydroxybenzoic acid [0166]
3,4-dihydroxyphenyl glycol [0167]
1,2-dihydroxy-4,5-dimethoxybenzene [0168] 3,5-dihydroxyacetophenone
monohydrate [0169] 3,4-dihydroxybenzoic acid monohydrate [0170]
3,4,5-trihydroxybenzaldehyde [0171] hexahydroxybenzene [0172]
3,5-dihydroxybenzylamine hydrochloride [0173] 4,6-diaminoresorcinol
hydrochloride [0174] 4,5-dichlorocatechol [0175]
3,5-dichlorocatechol [0176] 4,6-dichlororesorcinol [0177]
2',4'-dihydroxy-3'-methylpropiophenone [0178]
1-(3-ethyl-2,6-dihydroxyphenyl)ethan-1-one [0179]
3-(3,4-dihydroxyphenyl)propionic acid [0180]
(2,3,4-trihydroxyphenyl)acetone [0181]
(2,4,5-trihydroxyphenyl)acetone [0182]
(3,4,5-trihydroxyphenyl)acetone [0183]
2',6'-dihydroxy-4'-methoxyacetophenone [0184]
1-(2,6-dihydroxy-3-methoxyphenyl)ethan-1-one [0185]
3(2,4-dihydroxyphenylpropionic acid [0186]
2,4-dihydroxy-3,6-dimethylbenzoic acid [0187]
(2,3,4-trihydroxyphenyl)acetone [0188]
(2,4,5-trihydroxyphenyl)acetone [0189]
(2,4,6-trihydroxyphenyl)acetone [0190]
(3,4,5-trihydroxyphenyl)acetone [0191] 3,4-dihydroxymandelic acid
[0192] 5-hydroxyisovanillic acid [0193] 3,4,5-trihydroxybenzamide
hydrate [0194] 4-bromocatechol and the stereoisomers, organic or
mineral salts and solvates thereof.
Particularly Preferred Compounds of Formula (I):
[0194] [0195] resorcinol [0196] 2-methylresorcinol [0197]
5-methylresorcinol [0198] 4-methylresorcinol [0199] pyrogallol
[0200] 1,2,4-trihydroxybenzene [0201] 4-ethyl resorcinol [0202]
2,5-dimethylresorcinol [0203] 4,5-dimethylresorcinol [0204]
2,4-dimethyl-1,3-benzenediol [0205] 3,4-dihydroxybenzylamine [0206]
3,5-dihydroxybenzylamine [0207] 5-methylpyrogallol [0208]
3,4-dihydroxybenzyl alcohol [0209] 5-methoxyresorcinol [0210]
2,4,6-trihydroxytoluene [0211] 3,5-dihydroxybenzyl alcohol [0212]
2-methoxyresorcinol [0213] 5-methylpyrogallol [0214]
4-methoxyresorcinol [0215] 3,5-dihydroxytoluene monohydrate [0216]
4-propylresorcinol [0217] 2,4-dihydroxy-1,3,5-trimethylbenzene
[0218] 3,4-dihydroxybenzamide [0219] 3,5-dihydroxybenzamide [0220]
2,6-dihydroxybenzamide [0221] 2,4-dihydroxybenzamide [0222]
3-hydroxytyramine [0223] 2,3-dihydroxybenzoic acid [0224]
3,4-dihydroxybenzoic acid [0225] 2,6-dihydroxybenzoic acid [0226]
3,5-dihydroxybenzoic acid [0227] 2-(3,4-dihydroxyphenyl)ethanol
[0228] 2,4,6-trihydroxy-1,3-dimethylbenzene [0229]
2,6-dihydroxy-4-methylbenzyl alcohol [0230] 2-methoxyphloroglucinol
[0231] 3,5-dihydroxyanisole hydrate [0232] 4-aminoresorcinol
hydrochloride [0233] 2-aminoresorcinol hydrochloride [0234]
5-aminobenzene-1,3-diol hydrochloride [0235] phloroglucinol
dihydrate [0236] 2,4-diethyl-1,3-benzenediol [0237]
3,4-dihydroxyphenylacetamide [0238] 3,4-dihydroxyphenylacetic acid
[0239] 3,5-dihydroxy-4-methylbenzoic acid [0240]
2,6-dihydroxy-4-methylbenzoic acid [0241]
2,4-dihydroxy-6-methylbenzoic acid [0242] 3,5-dihydroxyphenylacetic
acid [0243] 2-ethyl-5-methoxybenzene-1,3-diol [0244]
3,4,5-trihydroxybenzamide [0245] 4-amino-3,5-dihydroxybenzoic acid
[0246] 3,4-trihydroxybenzoic acid [0247] gallic acid [0248]
2,4,6-trihydroxybenzoic acid [0249] DL-3,4-dihydroxyphenyl glycol
[0250] 1,2-dihydroxy-4,5-dimethoxybenzene [0251]
3,4-dihydroxybenzoic acid monohydrate [0252] hexahydroxybenzene
[0253] 3,5-dihydroxybenzylamine hydrochloride [0254] sodium
.gamma.-resorcylate [0255] sodium .beta.-resorcylate [0256]
4,6-diaminoresorcinol hydrochloride [0257]
3-(3,4-dihydroxyphenyl)propionic acid [0258]
2,4-dihydroxy-3,6-dimethylbenzoic acid [0259]
DL-3,4-dihydroxymandelic acid [0260] hydroxyisovanillic acid [0261]
3,4,5-trihydroxybenzamide acid hydrate [0262] gallic acid
monohydrate and the stereoisomers, organic or mineral salts and
solvates thereof.
Working Concentrations:
[0263] The working molar concentration is advantageously between 1
and 8 M, more advantageously between 1 and 4 M and even more
advantageously between 1.5 and 3 M.
[0264] The working pH is preferably less than or equal to 7.
[0265] The compositions according to the invention are either in
the form of an aqueous solution or in the form of a thickened cream
so as to keep the hair as straight as possible. These creams are
prepared in the form of "heavy" emulsions.
[0266] These compositions contain at least one polyhydroxylated
aromatic compound of formula (I) and/or mixtures of several
polyhydroxylated aromatic compounds of formula (I) in all
proportions.
[0267] Advantageously, the compositions of the invention contain
the polyhydroxylated aromatic compound as sole hair-relaxing active
agent.
[0268] For the purpose of improving the cosmetic properties of
keratin fibres or to attenuate or avoid their degradation, the
composition used according to the invention may also comprise one
or more additional cosmetic active agents.
[0269] Generally, the said additional cosmetic active agent(s)
represent(s) from 0.01% to 30% and preferably from 0.1% to 10% by
weight relative to the total weight of the cosmetic
composition.
[0270] Generally, the composition applied to the keratin fibres is
applied in an amount of from 0.05 to 20 g and preferably from 0.1
to 10 g of composition per gram of dry keratin fibre.
[0271] After applying the composition, and before raising the
temperature of the keratin fibres using a heating means, the said
composition may be left to act, generally for 30 seconds to 60
minutes and preferably 5 to 45 minutes.
[0272] The process according to the invention includes, after the
step of applying the composition, a step of raising the temperature
of the keratin fibres, using a heating means, to a temperature of
between 110.degree. C. and 250.degree. C.
[0273] Advantageously, an iron is used as heating means.
[0274] For the purposes of the present invention, the term "iron"
means a device for heating keratin fibres that places the said
fibres and the heating device in contact.
[0275] The end of the iron that comes into contact with the hair
generally having two flat surfaces. These two flat surfaces may be
metallic. They may be smooth or crinkled.
[0276] As examples of irons that may be used in the process
according to the invention, mention may be made of flat irons of
any type, and in particular, in a non-limiting manner, those
described in patents U.S. Pat. No. 5,957,140 and U.S. Pat. No.
5,046,516.
[0277] The iron may be applied by successive separate touches of a
few seconds, or by gradually moving or sliding it along the
locks.
[0278] Preferably, in the process according to the invention, the
iron is applied by continuous movement from the root to the end, in
one or more passes.
[0279] The process according to the invention may also include an
additional step of partial predrying of the keratin fibres before
the step of raising the temperature, so as to avoid substantial
evolution of steam that might burn the stylist's hands and the
individual's scalp. This predrying step may take place, for
example, using a hairdryer, a hood or alternatively by drying in
the open air.
[0280] The invention also relates to a kit comprising at least:
[0281] one heating means that affords a temperature of between 110
and 250.degree. C., [0282] one hair-relaxing composition containing
at least one polyhydroxylated aromatic compound, the pH of the
composition being less than or equal to 9, the polyhydroxylated
aromatic compound not being chosen from: [0283]
4,5-diamino-2,6-dihydroxypyrimidine, and [0284]
2,4-dihydroxypyrimidine-5-carboxylic acid.
[0285] Advantageously, in the kit, the hair-relaxing composition
contains at least one polyhydroxylated aromatic compound of formula
(I) as defined above.
[0286] The invention may be understood more clearly with the aid of
the non-limiting examples that follow, which constitute
preferential embodiments of the compositions according to the
invention.
EXAMPLE 1
[0287] A simplified hair-relaxing composition is prepared,
containing resorcinol at a concentration of 8 M in water, as
hair-relaxing active agent. This composition is applied to
naturally curly African hair for 15 minutes at a temperature of
40.degree. C., and the hair is then rapidly towel-dried.
[0288] Lock-by-lock straightening of the head of hair is then
performed using a flat iron heated to 180.degree. C., for 10 to 15
seconds. The hair is efficiently relaxed and feels soft.
EXAMPLE 2
[0289] A simplified hair-relaxing composition is prepared,
containing resorcinol at a concentration of 4 M in water, as
hair-relaxing active agent. This composition is applied to
naturally curly African hair for 15 minutes at a temperature of
40.degree. C., and the hair is then rapidly towel-dried.
[0290] Lock-by-lock straightening of the head of hair is then
performed using a flat iron heated to 180.degree. C., for 10 to 15
seconds. The hair is efficiently relaxed and feels soft.
EXAMPLE 3
[0291] A simplified hair-relaxing composition is prepared,
containing resorcinol at a concentration of 2 M in water, as
hair-relaxing active agent. This composition is applied to
naturally curly African hair for 25 minutes at a temperature of
40.degree. C., and the hair is then rapidly towel-dried.
[0292] Lock-by-lock straightening of the head of hair is then
performed using a flat iron heated to 180.degree. C., for 10 to 15
seconds. The hair is efficiently relaxed and feels soft.
* * * * *