Hair colorants with vat dyes
AssigneeWella Aktiengesellschaft
InventorsManuela Javet, Catherine Mueller, Anita Roulin
Life of this patent
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Abstract
The agent for dyeing hair has a pH of 4 to 11 and contains a reduced vat dye, which is obtained by reducing a vat dye, such as an anthrquinonoid dye, with a reducing agent compound that forms an enediol in an alkaline medium, preferably acetoin, monohydroxyacetone, and dihydroxyacetone. The method of dyeing hair includes pre-reducing the vat dye with the reducing agent compound at a pH of from 10 to 13 to form the reduced vat dye, providing an agent for dyeing the hair having a pH of from 4 to 11 and containing the reduced vat dye, allowing the agent to act on the hair while protecting the reduced vat dye in the agent from atmospheric oxygen, and then re-oxidizing with atmospheric oxygen or an oxidant.
Claims16
1-12. (canceled)
An agent for dyeing hair, said agent having a pH of 4 to 11 and containing at least one vat dye that is reduced by a reducing agent compound, said reducing agent compound forming an enediol in an alkaline medium.
A method of dyeing hair, said method comprising the steps of:
- a) pre-reducing at least one vat dye with a reducing agent compound to form at least one reduced vat dye, said reducing agent compound having an enediol form in a strongly alkaline medium having a pH of from 10 to 13;
- b) providing an agent for dyeing the hair having a pH of from 4 to 11 and containing said at least one reduced vat dye;
- and
- c) applying the agent for dyeing the hair to the hair.
Dependencies are inferred from the claim text.