Method of coloring hair with direct dye compounds
View Patent ↗Described herein is a method of dyeing the hair. The method includes applying to the hair a hair color composition including one or more direct dye compounds and rinsing the hair with water. The one or more direct dye compounds each include a chromophore, one or two permanent cations, and one to four incipient cations. The one to four incipient cations are pendant to the core structure and are neutral. The one or more direct dye compounds enter the hair shaft after the hair color composition is applied to the hair. The hair color composition has a pH of from about 7 to about 11. The pH of the hair after rinsing is from about 3.5 to about 6. The rinsing of the hair causes one or more of the one to four incipient cations to change from neutral to positively charged inside of the hair shaft.
1. A method of dyeing the hair, the method comprising:
a. applying to the hair a hair color composition comprising one or more direct dye compounds, the one or more direct dye compounds each comprising:
i. a chromophore;
ii. one or two permanent cations, wherein the permanent cations are pendant to the chromophore or part of the chromophore, and wherein the chromophore and the permanent cations form a core structure; and
iii. one to four incipient cations, wherein each of the one to four incipient cations is pendant via a linker group to the core structure, and wherein the incipient cations are neutral;
wherein the one or more direct dye compounds enter the hair aft after the hair color composition is applied to the hair; and
wherein the hair color composition has a pH of from about 7 to about 11;
b. rinsing the hair with water;
wherein the pH of the hair after rinsing is from about 3.5 to about 6; and
wherein the rinsing of the hair causes one or more of the one to four incipient cations to change from neutral to positively charged inside of the hair shaft,
wherein the chromophore has a structure according to Formula (Xn) or a tautomer or salt thereof:
wherein
(i) R 14b , R 14c , R 14d , R 14e , R 14h , R 14i , R 14j , R 14k , R 14l and R 14m are each independently hydrogen, alkyl, halogen substituted alkyl, alkenyl, alkynyl, aryl, hydroxyl alkyl, alkoxy, aryloxy, acyl, halogen, nitro, nitroso, cvano, a heterocyclic moiety, thioether or are attached to a linker with or without a terminal amino group;
(ii) R 14a is C 1 -C 8 alkyl or a linker group with a primary, secondary, or tertiary amino group attached;
(iii) R 14g and R 14h are each independently hydrogen, C 1 -C 8 alkyl, hydroxyl alkyl, or a linker group with a primary, secondary, or tertiary amino group attached; and
(iv) the total number of amino groups attached to R 14a , R 14f , R 14g is 2-3 and wherein the amino groups can be primary, secondary, or tertiary.
2. The method of claim 1 , wherein the one or more direct dye compounds each comprise two incipient cations.
3. The method of claim 1 , wherein the one or more direct dye compounds each has a molecular weight of less than about 1,000 g/mol.
4. The method of claim 1 , wherein the hair color composition has a pH of from about 9 to about 11.
5. The method of claim 1 , wherein the hair color composition has a pH of fro about 7 to about 9.
6. The method of claim 1 , wherein an oxidizing agent is applied before or during the application of the hair color composition.
7. The method of claim 6 , wherein the oxidizing agent is selected from the group consisting of peroxides, perborates, percarbonates, persulfates, oxidant generating enzymes, oxidant generating substrates, and combinations thereof.
8. The method of claim 1 , wherein the hair color composition further comprises one or more oxidation dyes.