METHOD FOR STRAIGHTENING HUMAN HAIR FIBERS USING HEATING MEANS AND AN a-KETO ACID DERIVATIVE

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 alpha-hydroxy and/or keto acid derivative, the pH of said composition being not more than 9 (ii) a step of increasing the temperature of the keratinous fibers, using heating means, to a temperature ranging between 110 and 250 C.

Claims

1-14. (canceled)

15. A process for relaxing human hair fibers, comprising: applying to the hair fibers a hair-relaxing composition comprising at least one -keto acid derivative, wherein the pH of the composition is less than or equal to 9, and heating the hair fibers to a temperature ranging from 110 C. to 250 C.

16. A process according to claim 15, wherein the hair fibers are heated to a temperature ranging from 120 C. to 220 C.

17. A process according to claim 16, wherein the hair fibers are heated to a temperature ranging from 140 C. to 220 C.

18. The process according to claim 15, wherein the composition is applied to wet hair fibers.

19. The process according to claim 15, wherein the hair fibers are partially predried.

20. The process accordin to claim 15, wherein the molar concentration of the at leat one -keto acid derivative is from 2 to 8 M.

21. The process according to claim 20, wherein the molar concentration of the at least one -keto acid derivative is from 4 to 8 M.

22. The process according to claim 15, wherein the pH of the composition is less than or equal to 7.

23. The process according to claim 15, wherein the at least one a-keto acid derivative is chosen from compounds of formula (II): ##STR00008## wherein R.sub.5 is chosen from: H, COOH, a linear or branched C.sub.1-C.sub.6 alkyl optionally substituted with an OH, COOH, or Br radical; a phenyl or benzyl optionally substituted with an OH or COOH radical; or an indolyl radical or ##STR00009## and the stereoisomers and organic or mineral salts thereof.

24. The process according to claim 23, wherein the compounds of formula (II) are chosen from: 2-ketobutyric acid, -hydroxypyruvic acid, 3-methyl-2-oxobutyric acid, 2-oxovaleric acid, ketomalonic acid, 3-methyl-2-oxovaleric acid, trimethylpyruvic acid, oxoacetic acid, 2-ketoglutaric acid, benzylformic acid, 2-oxooctanoic acid, 2-oxoadipic acid, phenylpyruvic acid, bromopyruvic acid, 2-ketopimelic acid, 4-hydroxyphenylpyruvic acid, 3-indoleglyoxalic acid, imidazolopyruvic acid HCl, 2-keto-L-gulonic acid, 2-carboxy-a-oxobenzeneacetic acid, 3-indolepyruvic acid, 2-ketoglutaric acid dihydrate, pyruvamide, N-methylpyruvamide, N-ethylpyruvamide, N,N-dimethylpyruvamide, N-2-hydroxyethylpyruvamide, and the stereoisomers and organic or mineral salts thereof.

25. The process according to claim 24, wherein the compounds of formula (II) are chosen from: 2-ketobutyric acid, -hydroxypyruvic acid, ketomalonic acid, oxoacetic acid, 2-ketoglutaric acid, 2-keto-L-gulonic acid, 2-ketoglutaric acid dihydrate, and pyruvamide.

26. A kit comprising at least: a heating apparatus that provides a temperature ranging from 110 C. to 250 C., at least one hair-relaxing composition comprising at least one -keto acid derivative, wherein the pH of the at least one composition is less than or equal to 9.

27. A kit according to claim 26, wherein the hair-relaxing composition comprises at least one -keto acid chosen from: 2-ketobutyric acid, -hydroxypyruvic acid, 3-methyl-2-oxobutyric acid, 2-oxovaleric acid, ketomalonic acid, 3-methyl-2-oxovaleric acid, trimethylpyruvic acid, oxoacetic acid, 2-ketoglutaric acid, benzylformic acid, 2-oxooctanoic acid, 2-oxoadipic acid, phenylpyruvic acid, bromopyruvic acid, 2-ketopimelic acid, 4-hydroxyphenylpyruvic acid, 3-indoleglyoxalic acid, imidazolopyruvic acid HCl, 2-keto-L-gulconic acid, 2-carboxy--oxobenzeneacetic acid, 3-indolepyruvic acid, 2-ketoglutaric acid dihydrate, pyruvamide, N-methylpyruvamide, N-ethylpyruvamide, N,N-dimethylpyruvamide, N-2-hydroxyethylpyruvamide, and the stereoisomers and organic or mineral salts, or mixtures thereof in all proportions.

Description

EXAMPLE 1

[0184] A simplified hair-relaxing composition is prepared, containing DL-lactic acid 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 C., and the hair is then rapidly towel-dried.

[0185] Lock-by-lock straightening of the head of hair is then performed using a flat iron heated to 180 C., for 10 to 15 seconds. The hair is efficiently relaxed and feels soft.

EXAMPLE 2

[0186] A simplified hair-relaxing composition is prepared, containing pyruvic acid 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 C., and the hair is then rapidly towel-dried.

[0187] Lock-by-lock straightening of the head of hair is then performed using a flat iron heated to 180 C., for 10 to 15 seconds. The hair is efficiently relaxed and feels soft.

EXAMPLE 3

[0188] A simplified hair-relaxing composition is prepared, containing pyruvic acid at a concentration of 4 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 C., and the hair is then rapidly towel-dried.

[0189] Lock-by-lock straightening of the head of hair is then performed using a flat iron heated to 180 C., for 10 to 15 seconds. The hair is efficiently relaxed and feels soft.

EXAMPLE 4

[0190] A simplified hair-relaxing composition is prepared, containing L-lactic acid at a concentration of 4 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 C., and the hair is then rapidly towel-dried.

[0191] Lock-by-lock straightening of the head of hair is then performed using a flat iron heated to 180 C., for 10 to 15 seconds. The hair is efficiently relaxed and feels soft.