PROCESS FOR PRODUCTION OF ZINC OXIDE FINE-PARTICLE POWDER AND COSMETICS CONTAINING THE POWDER

摘要

[PROBLEMS] To provide a process for the production of zinc oxide powder excellent in ultraviolet-screening effect and transparency; and cosmetics containing the powder. [MEANS FOR SOLVING PROBLEMS] A zinc oxide fine-particle powder is obtained by subjecting either an aqueous solution containing both a water-soluble zinc salt and a carboxylic acid or an aqueous solution containing a water-soluble zinc carboxylate to pH adjustment with an alkali carbonate agent and aging the resulting solution without firing. The alkali carbonate agent may take the form of a 0.1 to 2mol/L aqueous solution and the ratio of carboxyl to zinc may be 1 to 5 by mole. The pH adjustment can be conducted by adding the aqueous solution of an alkali carbonate agent dropwise to either an aqueous solution containing both a water-soluble zinc salt and a carboxylic acid or an aqueous solution containing a water-soluble zinc carboxylate at a rate of 0.5 to 5mL/min per 100mL of the solution.