THICK NANOCOLLOIDAL GOLD LIQUID, FINE GOLD PARTICLE, AND THEIR MANUFACTURING METHODS

摘要

PROBLEM TO BE SOLVED: To provide materials for various uses, such as a thick and stable nanocolloidal gold liquid, a fine gold particle and a gold paste obtained by reducing a thick aqueous solution of chloroauric acid at a reaction temperature in a wide range from low temperature to ordinary temperature without requiring operation of concentration and addition of protective colloid agent for preparation of thick gold colloid. SOLUTION: An alkali salt of spiculisporic acid (a safety biosurfactant of biological origin, having a tribasic acid type structure) and an alkali salt of a lactone ring-opened substance thereof are used both as a reducing agent and a colloid protecting and stabilizing agent. These are added to an aqueous solution of chloroauric acid, and the resulting mixture is mixed by shaking at a temperature ranging from ordinary temperature to high temperature (5 to 80°C) and is then allowed to stand still. The aqueous solution of chloroauric acid having high to low concentration (0.1 mmol/l to 2.43 mol/l) is reduced to form gold nanoparticles, and the number of nucleations of gold as a simple substance and the uniting thereof are controlled, and the resulting gold colloid is provided with a high dispersion stabilizing action. COPYRIGHT: (C)2009,JPO&INPIT