Method of preparing metal particle dispersion
A method of preparing metal particle dispersion includes preparing an ion-containing solution that contains metal ions (step S 11 ), performing heat treatment on a protectant having an average molecular weight of greater than or equal to 5000 and less than or equal to 32500 (step S 12 ), and mixing the aforementioned ion-containing solution, a reducing agent, and the protectant subjected to the heat treatment in step S 12 to prepare metal particle dispersion in which metal microparticles are dispersed by a liquid-phase reduction method (step S 13 ). This method achieves improved dispersibility and further fragmentation of the metal microparticles in the metal particle dispersion.
1 . A method of preparing metal particle dispersion, comprising:
a) preparing an ion-containing solution that contains metal ions;
b) performing heat treatment on a protectant having an average molecular weight of greater than or equal to 5000 and less than or equal to 32500; and
c) mixing said ion-containing solution, a reducing agent, and said protectant subjected to the heat treatment in said operation b) to prepare metal particle dispersion in which metal microparticles are dispersed by a liquid-phase reduction method.
2 . The method of preparing metal particle dispersion according to claim 1 , wherein
said metal microparticles are silver microparticles.
3 . The method of preparing metal particle dispersion according to claim 2 , wherein
said protectant is polyvinyl pyrrolidone.
4 . The method of preparing metal particle dispersion according to claim 3 , wherein
said protectant has a K-value of greater than or equal to 12.0 and less than or equal to 27.0.
5 . The method of preparing metal particle dispersion according to claim 2 , wherein
said reducing agent is triethanolamine.
6 . The method of preparing metal particle dispersion according to claim 1 , wherein
a heating temperature in said heat treatment is higher than or equal to 100° C. and lower than or equal to 150° C.
7 . The method of preparing metal particle dispersion according to claim 1 , wherein
said metal microparticles in said metal particle dispersion prepared in said operation c) have an average particle diameter of less than or equal to 10 nm.