Semipermanent Hair Colourants/ Direct dyes: Retain co \ or for Ianger duration. Doesnot contain H2O2 and so it doesnt get bieached Com position of semipermanent hair colora stsa re Dye - O n itro aniIines, Aminonitroph enols & their ethers, Azo dyes,N itrodiphenylamine, Anthroquinone AI ip hatic primarya mines, Fatty aci¢J, Th ickener, Surfactant VU ate r, rganic solvent,Perfume Oxidative Dyeing S v stems Also caIIed Para dyes. Colorantsa re based on chemical reaction, produces color. Mostly oxidation, coupling and condensation reactions involved Compositiona re, Dyes - Aromatic compounds, Resorcinal, m- phenylene diamine, Dia minoanisole, hydrogen peroxide Vehicles - Water, Ethyl alcohol, G !v cerine, Ethylene glycol monostearate Alkalis Oxidation dyes are active in alkaline medium Eg: Ammonium hydroxide, Amm. Carbonate, Mono ethanol amine, Guanidine or Arginine, Diethanol amine Oxidizing agent - Induces the oxidation reaction with hair Eg: Ferric chloride, Kmno4, H 2O2 Antioxidant - During manufacturing, thea mino dyesa re da rken in presence of air. Nitrogen is supplied in manufacturing vessel or Sodium sulfite a re added