Cationic para-aminophenol oxidation base for hair dye

The invention modifies the chemical structure of para-aminophenol oxidation bases by introducing cationic groups (such as quaternary ammonium groups) at specific positions (ortho or meta to the amino group). This structural parameter change transforms neutral oxidation bases into cationic ones, which significantly improves color intensity and chromaticity while maintaining the ease of the dyeing process. The cationic charge enables better interaction with keratin fibers, resulting in more vibrant and intense hair coloring.

By changing the chemical parameter of the oxidation base from neutral to cationic through the introduction of charged groups, the invention achieves superior resistance to external agents. The cationic character enhances the binding affinity to negatively charged sites on hair keratin, creating more durable color fastness against light, washing, and perspiration. This single parameter change (adding cationic groups) simultaneously improves multiple performance aspects without complicating the formulation process.

The introduction of cationic groups into the oxidation base structure changes its electrostatic properties, enabling more uniform distribution and interaction along the hair fiber. The positive charge allows the dye to interact more consistently with the negatively charged keratin surfaces, reducing selectivity and improving color uniformity from root to tip. This parameter change maintains application simplicity while achieving superior color homogeneity.