DHA as a hair colourant
View Patent ↗There is described a method for colouring hair, said method comprising treating hair with a composition comprising dihydroxyacetone (DHA), in free form or in salt form; optionally drying the hair; and heating the treated hair, including the applied DHA composition, to a temperature of from about 100° C. to about 250° C.
1. A method for colouring hair, said method comprising treating hair with a composition comprising dihydroxyacetone (DHA), in free form or in salt form; optionally drying the hair; and heating the treated hair, including the applied DHA composition, to a temperature of from about 100° C. to about 250° C.;
provided that said composition does not include additional colorants.
2. The method according to claim 1 which comprises applying the DHA composition to select portions of the hair.
3. The method according to claim 1 which comprises applying the DHA composition to all of the hair of the head.
4. The method according to claim 1 wherein the DHA composition is applied to dry hair, wet hair or damp hair.
5. The method according to claim 1 wherein the hair is shampooed or rinsed prior to the application of the DHA composition.
6. The method according to claim 1 wherein heat is applied to the DHA treated hair within about 5 minutes after application of the DHA.
7. The method according to claim 1 wherein the treated hair is heated for a time period from about 1 minute to about 60 minutes.
8. The method according to claim 1 wherein a hot iron is used to apply heat to the treated hair.
9. The method according to claim 8 wherein the hot iron is selected from the group consisting of a curling iron, a straightening iron or a hot comb.
10. The method according to claim 1 wherein after the heating is complete, the hair is rinsed or shampooed as desired.
11. The method according to claim 1 wherein the amount of DHA, in free form or in salt form, present in the composition is from about 1 to about 20% w/w.
12. The method according to claim 1 wherein the DHA composition is oil based or is an aqueous solution.
13. The method according to claim 1 wherein the DHA composition includes one or more water-soluble solvents.
14. The method according to claim 13 wherein the one or more water-soluble solvents is selected from the group consisting of glycerin, mono-alcohols, polyols (polyhydric alcohols), glycols, and mixtures thereof.
15. The method use according to claim 1 wherein the DHA composition includes one or more thickening agents.
16. A kit for colouring hair, said kit comprising:
a composition comprising dihydroxyacetone (DHA), in free form or in salt form; provided that said composition does not include additional colorants;
optionally an applicator for the DHA composition; and
means for heating the treated hair.
17. A kit according to claim 16 wherein the means for heating the treated hair is capable of heating the treated hair to a temperature of from about 100° C. to about 250° C.