Metal microparticle dispersion, process for production of electrically conductive substrate, and electrically conductive substrate

Abstract

Provided is a metal microparticle dispersion including metal microparticles, a polymeric dispersant and a dispersion medium, wherein an average primary particle diameter of the metal microparticles is 0.001 to 0.5 μm; the polymeric dispersant has a polyester skeleton in at least one of a principal chain and a side chain thereof; or the polymeric dispersant has a polyether skeleton in at least one of a principal chain and a side chain thereof; and a content of the above polymeric dispersant is 0.1 to 100 parts by mass based on a content of 100 parts by mass of the metal microparticles. Further, provided is a production process for an electrically conductive substrate, and an electrically conductive substrate produced by the above production process is provided.

1 . A metal microparticle dispersion comprising metal microparticles, a polymeric dispersant and a dispersion medium, wherein an average primary particle diameter of the metal microparticles is 0.001 to 0.5 μm; the polymeric dispersant has a polyester skeleton in at least one of a principal chain and a side chain thereof; the above polyester skeleton has at least one of a constitutional unit derived from valerolactone and a constitutional unit derived from caprolactone, and a sum of the numbers of the above constitutional units is 10 or more in terms of an average value; and a content of the above polymeric dispersant is 0.1 to 100 parts by mass based on a content of 100 parts by mass of the metal microparticles. 
     
     
         2 . The metal microparticle dispersion according to  claim 1 , wherein a side chain of the polymeric dispersant is a polyester skeleton or a polyether skeleton, and a principal chain is a polyamine skeleton or a polyimine skeleton. 
     
     
         3 . The metal microparticle dispersion according to  claim 1 , wherein metal constituting the metal microparticle dispersion is at least one selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, tin, iron, chromium, indium, silicon and germanium. 
     
     
         4 . The metal microparticle dispersion according to  claim 1 , wherein the metal microparticles are copper microparticles. 
     
     
         5 . The metal microparticle dispersion according to  claim 4 , wherein the copper microparticles are formed by mixing divalent copper oxide with a reducing agent in a medium under the presence of a complexing agent and a protective colloid. 
     
     
         6 . The metal microparticle dispersion according to  claim 4 , wherein a donor atom of a ligand in the complexing agent is at least one selected from the group consisting of nitrogen, oxygen and sulfur. 
     
     
         7 . The metal microparticle dispersion according to  claim 5 , wherein the protective colloid is a protein base protective agent. 
     
     
         8 . The metal microparticle dispersion according to  claim 2 , wherein a principal chain of the polymeric dispersant comprises polyethyleneimine. 
     
     
         9 . The metal microparticle dispersion according to  claim 2 , wherein a principal chain of the polymeric dispersant comprises polyallylamine. 
     
     
         10 . The metal microparticle dispersion according to  claim 1 , wherein the dispersion medium is at least one selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, ketones, esters and alcohols. 
     
     
         11 . A production process for an electrically conductive substrate, comprising printing a coating solution containing the metal microparticle dispersion according to  claim 1  in a pattern-like form on a base material to form a printed layer and subjecting the above printed layer to burning treatment to form a pattern-like metal microparticle sintered film. 
     
     
         12 . The production process for an electrically conductive substrate according to  claim 11 , wherein the burning is carried out by a surface wave plasma generated by applying a microwave energy. 
     
     
         13 . The production process for an electrically conductive substrate according to  claim 12 , wherein the burning is carried out by a surface wave plasma generated under inert gas atmosphere and/or reducing gas atmosphere. 
     
     
         14 . The production process for an electrically conductive substrate according to  claim 11 , wherein the burning comprises (i) a step in which burning is carried out at 165° C. or lower under atmosphere containing oxygen and (ii) a step in which burning is carried out at 165° C. or lower by a surface wave plasma under inert gas atmosphere and/or reducing gas atmosphere. 
     
     
         15 . An electrically conductive substrate produced by the production process according to  claim 11 .