| 摘要 |
PURPOSE: A water soluble black coloring agent, its preparation method and a bolt and a nut coated by using the coloring agent are provided, to improve the corrosion resistance and the productivity, to reduce the environmental pollution and to enable the coated film to be removed easily. CONSTITUTION: The water soluble black coloring agent is prepared by mixing carbon black pigment powder, water and a liquid surfactant to prepare an aqueous coloring agent solution; adding soap-component surfactant I(a nonionic surfactant) and surfactant II(an anionic surfactant) to the aqueous coloring agent solution to prepare a pigment-dispersed solution; and adding an antifoaming agent and water to the pigment-dispersed solution to dilute it, and mixing it with stirring. Preferably the liquid surfactant is ethylene glycol; the surfactant I is polyoxyalkylene alkylphenylether; and the surfactant II is RCOONa(wherein R is a hydrocarbon group of C10-C18). |
