Method for producing a highly conductive ultrafine tin dioxide

摘要

PURPOSE:To provide the nontoxic, safe tin dioxide, free from blue-black color due to antimony, excellent in transparency in itself, capable of giving any color tone through its combination with colorants, and improved in moisture resistance and stability with time. CONSTITUTION:The objective electrically conductive ultrafine tin dioxide consisting of (A) tin dioxide and (B) at least one kind of dopant selected from each 0.1-10wt.%, on a tin dioxide basis, of pentavalent Nb and Ta, having the following characteristics: (1) particle diameter for D90 in particle size distribution: 0.01-5mum; (2) specific surface area: 5-100m2/g, and (3) volume resistivity: 10-2-103OMEGA.cm. The ultrafine tin dioxide can be obtained by the following process: a reaction vessel is charged with a solution containing a stannic salt and a Nb and/or Ta compound(s) and a neutralizing the solution separately and simultaneously, immediately followed by high-speed agitation of both the solutions together; in this case, the inside of the vessel is maintained at a specified constant pH level within the pH range of 2-12 and a coprecipitate is deposited continuously, recovered, dried, and then baked in an inert or weakly reductive atmosphere to impart the objective tin dioxide with electrical conductivity.