Effect of cationic charge and hydrophobic index of cellulose‐based polymers on the semipermanent dyestuff process for hair

In this work, the effects of a new class of polymers generally used in hair and skin cleansing products, the SoftCAT (SofCAT SL and SoftCAT SX), on the dye uptake on the hair fibre and the fading effects has been studied. These polymers, based on quaternary ammonium salts of hydroxyethylcellulose, are cationic products that differ in viscosity, hydrophobic substitution index (HS) and/or cationic substitution (CS, % N). UV–Vis spectroscopy has been used to analyse the extracted dyes from the hair cuticle and the cortex. The results indicate that the presence of polymers in the dye bath improve both the quality of the dyeing process and the anti‐fading effect during the washing cycles. This phenomenon is postulated to be attributable to the polymers hydrophobically bonding with the dyes and so facilitating their increased penetration into the hair.