EFFECT PIGMENT COATED WITH NITROGEN-DOPED CARBON AND PREPARATION THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain excellent optical characteristics such as high reflectance, brightness, gloss and opacity by forming a film layer of a compound containing carbon, nitrogen and a specific element on a core surface. SOLUTION: An effect pigment comprises an aggregate of composite platelet- shaped particles containing a core and a film layer (nitrogen-doped carbon film) substantially comprising a compound containing 60-95 wt.% of carbon and 5-25 wt.% of nitrogen and the balance up to 100% of an element selected from hydrogen, oxygen and sulfur. A preparation method of this particle aggregate is as follows: (A) to suspend platelet-shaped particles in a liquid; (B) to add a surface modifier and/or a polymerization catalyst in some cases; (C) to add a polymer or a monomer containing nitrogen atoms and carbon atoms before or after step B; (D) to allow a polymer film layer to be formed on the surface of the platelet-shaped particles from this polymer or monomer; (E) to isolate the filmed platelet-shaped particles from the suspension; and (F) to heat these particles to 100-1,000 deg.C in a gaseous environmant.