Study On The Preparation Of Waterborne UV-curable Silver-based Conductive Ink

At present,most of the conductive ink on the market is the high temperature sintering drying mode,and the conductive silver paste is mostly micron grade silver particles,which hinders the development of printing electronic industry in its conductivity and drying methods.Waterborne UV-curable silver-based conductive ink has the advantages of environmental protection and energy saving,and can be applied to the screen or ink-jet printing.The purpose of this paper is to prepare a kind of environmentally friendly and energy saving waterborne UV-curable silver-based conductive ink,which is cured by UV curing and thermal drying in two ways.Waterborne UV-curable silver-based conductive ink is a new type of conductive ink.Compared with the traditional conductive ink,the ink has the advantages of no toxicity,no pollution,low volatile organic compounds(VOCs)etc.,it combines the characteristics of water-based ink and ultraviolet curing ink.Nano silver was chosen as the conductive filler,and the modified resin was used as the connecting material.In this paper,the modification of resin and the preparation of silver were studied,and the optimization scheme was obtained.The main results were as follows:(1)The preparation of waterborne UV-curable prepolymer was one of the main contents of this paper.By testing the reaction process of the iodine value,acid value,and the prepolymer viscosity,surface tension,curing rate and other properties,determined the optimum reaction process.The molar ratio of epoxy resin and acrylic acid was equal to 1:1.05,the reaction temperature was 92 ?.The molar ratio of epoxy and maleic anhydride was equal to 1:0.9,the reaction temperature was 90 ?.And the amount of catalyst and polymerization agent in the total system was 1%and 0.25%respectively.Adding sodium bicarbonate neutralization reaction system,the neutralization degree was 100%,Waterborne UV-curable resin had the best comprehensive performance.(2)Prepared silver nanoparticles by reduction of inorganic silver source.The best preparation process was as follows:the reaction temperature was 50 ?,the molar ratio PVP and silver ammonia solution was 1.5:1,the mass fraction of hydrazine hydrate was 5%.When the pH value of the system was between 7.5?8.5,it was relatively stable.(3)Silver nanoparticles was prepared by mixing epoxy acrylate with silver ammonia complex ion.By in-situ chemical reduction method,the silver nanoparticles was obtained in epoxy acrylate system.The preparation process was as follows:the molar ratio of epoxy acrylate and silver ammonia complex ion was 4:1,reaction temperature was 50 ?,the concentration of hydrazine hydrate was 5 wt%,the product of the diameter was about 100 nm,and ultraviolet visible light absorption of particles peak was at 425 nm.When the ratio of photoinitiator 369 and TPO was equal to 1.5:1,it could gain the best curing effect,and the curing time was about 3.1 s.The conductive ink with silver of 5 wt%.One was directly blended with AgNPs.The other was a composite system formed by the molar ratio of EC-Na and Ag(NH3)2+ to 4:1,and then blended with EC-Na after reduction of silver and AgNPs.Through the test of conductivity of the film,it could be seen that the molar ratio of EC-Na to Ag(NH3)2+ is 4:1,and the composite system could improve the conductivity of the film to some extent.(4)Studied on the preparation and properties of waterborne UV-curable silver-based conductive ink.In this experiment,EC-Na and Ag(NH3)2+ molar ratio of 4:1 formed a composite system,reducing silver,and then blending with AgNPs.The influence of AgNPs content,heat treatment temperature and time on the conductivity was also tested.The optimum content:AgNPs content is 5 wt%,and the temperature and time of heat treatment are 180 and 45 min respectively.The optimum condition was that the content of AgNPs was 20 wt%,and the temperature and time of heat treatment was 180 and 45 min respectively.