Hair colouration, method and kit thereof
View Patent ↗Method for coloring hair wherein a first composition comprising at least one cationic polymer and a second composition comprising at least one anionic polymer are alternately applied to the hair.
1. A method for colouring hair comprising:
a) carrying out the following sequence of steps:
i) applying a first composition comprising colored cationic polymer to a first portion of the hair, wherein the colored cationic polymer is polyethleneimine; and
ii) applying a second composition comprising anionic polymer to a second portion of the hair, wherein the anionic polymer is a dextran sulfate sodium salt;
the first and the second portions of the hair having at least one common area; and the first composition comprises a total concentration of polyethleneimine ranging from 0.1 g/L to 100 g/L or the second composition comprises a total concentration of dextran sulfate sodium salt ranging from 0.1 g/L to 100 g/L.
2. The method according to claim 1 , wherein the method further comprises:
b) repeating step a) at least once, wherein the common area of each of the repeated steps a) has at least one common area with:
the common area of step a); and
the common area of each of the other repeated steps a) in case step a) is repeated more than once.
3. The method according to claim 1 , wherein step i) or ii) further comprises the subsequent sub-steps of:
removing the excess of respectively the first composition or the second composition from the hair or
applying energy to the hair in the form of heat, ultrasounds, infrared or microwaves or washing or rinsing the hair.
4. The method according to claim 1 , wherein:
the colored cationic polymer has a weight average molecular weight ranging from 0.5 kD to 5000 kD and
the anionic polymer has a weight average molecular weight ranging from 10 kD to 1000 kD.
5. The method according to claim 1 , wherein the first or the second composition has a pH ranging from 2 to 14.
6. The method according to claim 1 , wherein the first or the second composition comprises a cosmetically acceptable salt at a concentration ranging from 0.05 to 1.5 mat.
7. The method according to claim 1 , wherein prior to step a), the hair is pretreated to modify the number of positive or negative charges in some portions of the hair or all over the hair.