| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a purification method for a dispersion solution to remove soluble impurities or a surface active agent in an aqueous dispersion solution of fine particles of carbon and a fluororesin used for manufacturing a gas diffusion electrode without impairing a well-dispersed state of the particles. <P>SOLUTION: Fine particles of the raw material are dispersed using a dispersion accelerating means in a 2-6% aqueous solution of a nonionic surface active agent whose mass is 10 to 30 times greater than that of the particles, and the dispersion solution is separated into a particle concentrate and a supernatant fluid by centrifugation. Then, the particle concentrate is collected and re-dispersed in pure water or in a high-purity aqueous solution of a nonionic surface active agent. The original dispersion solution is stored for a specified time at a temperature higher than the cloud point of the nonionic surface active agent before centrifugation. The operation of further concentrating the dispersion solution purified in the above-described manner by centrifugation and then re-dispersing the particle concentrate in pure water or in a high-purity aqueous solution of the nonionic surface active agent is repeated as necessary. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
