GREEN POWDER AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a green powder capable of being produced by an inexpensive and safe method without using an expensive raw material and dangerous organic solvent by forming a specific coating film on the surface of substrate particles. SOLUTION: This green powder is obtained by forming a coating film whose at least one layer is formed on the surface of each of substrate particles through reaction of a metal salt in an aqueous solvent and which gives a reflection spectrum having a peak at 450-650 nm. It is preferable that the coating film formed through reaction of the metal salt in the aqueous solvent satisfies the formula Nd=mλ/4 [N=n+iκ(n is the refractive index of a substance constituting the film; i is a complex number;κis a damping coefficient); d is a film thickness; m is a natural number;λis a peak wavelength of the reflection spectrum given by the powder, 450-650 nm]. This green powder can be used for various purposes such as inks, fillers for plastics and papers, toners, and inks for ink-jet printers.