Mixture of amides and cosmetic compositions comprising said mixture

1. A mixture of amides of the following formula (I)

wherein

R 1 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;

R 2 and R 3 represent independently, a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms which is optionally hydroxylated, provided that R 2 and R 3 are not a hydrogen atom at the same time;

n has a value in the range of 0.2 to lower than 3;

characterized in that said mixture comprises:

amides (a) of formula (I) wherein

R represents a C 6 -C 24 alkyl or alkenyl group having an even number of carbon atoms and at least a 95 wt. % of linearity; and

amides (b) of formula (I) wherein

R represents a C 5 -C 23 alkyl or alkenyl group having an odd or odd and even number of carbon atoms and a 35-85 wt. % of linearity.

2. The mixture of amides according to claim 1 , wherein in the amides (a) of formula (I) R represents a C 8 -C 18 alkyl or alkenyl group having an even number of carbon atoms and at least a 98 wt. % of linearity.

3. The mixture of amides according to claim 1 , wherein in the amides (b) of formula (I) R represents a C 5 - C 17 alkyl or alkenyl group having an odd or odd and even number of carbon atoms and a 40-75 wt. % of linearity.

4. The mixture of amides according to claim 1 , wherein the weight ratio of amides (a) to amides (b) is in the range of 1:10 to 10:1.

5. The mixture of amides according to claim 4 , wherein the weight ratio of amides (a) to amides (b) is in the range of 1:5 to 5:1.

6. The mixture of amides according to claim 1 , wherein R 2 and R 3 represent independently, a hydrogen atom or a hydroxylated alkyl group having 1 to 5 carbon atoms selected from the group consisting of hydroxymethyl, hydroxyethyl, n-hydroxypropyl, iso-hydroxypropyl, n-hydroxybutyl, iso-ydroxybutyl, tert-hydroxybutyl and n-hydroxypentyl; provided that either R 2 or R 3 is not a hydrogen atom.

7. The mixture of amides according to claim 6 , wherein R 2 represents a hydrogen atom or a hydroxyethyl group and R 3 represents a hydroxyethyl, n-hydroxypropyl or iso-hydroxypropyl group.

8. The mixture of amides according to claim 1 wherein R 1 represents a hydrogen atom, R 2 represents a hydrogen atom and R 3 represents a hydroxyethyl group.

9. A cosmetic composition comprising a mixture of amides according to claim 1 .

10. A dyeing composition comprising

a) a dyestuff; and

b) a mixture of amides, said mixture comprising, based on the total amount of the amide mixture:

i) 5-100 wt. % of amides (a) as defined in claim 1 , and ii) 0-95 wt. % of amides (b) as defined in claim 1 .

11. The composition according to claim 10 , wherein the weight ratio of amides (a) to amides (b) is in the range of 1:10 to 10:1.

12. The composition according to claim 10 comprising, based on the total amount of the amide mixture:

i) 20-70 wt. % of amides (a), and

ii) 30-80 wt. % of amides (b).

13. The composition according to claim 10 , further comprising an oxidizing agent.

14. The composition according to claim 10 further comprising an oxidation dye.

15. The composition according to claim 10 , wherein the mixture of amides is present in an amount of 0.05 to 25 wt. % with respect to the total weight of the composition.

16. A method for dyeing keratinous fibres comprising applying an effective amount of at least one composition according to claim 10 to keratinous fibres.

17. The method for dyeing keratinous fibres according to claim 16 , wherein said keratinous fibres are human hair.

18. A composition for dyeing keratinous fibres comprising mixture of amides according to claim 1 as a levelling agent.

19. A composition for dyeing keratinous fibres comprising a mixture of amides according to claim 1 as a thickening agent.

20. The composition according to claim 19 , wherein said keratinous fibres are human hair.