Environmentally-friendly printed circuit board conductive silver paste and preparing method thereof

Environmentally-friendly printed circuit board conductive silver paste is prepared from, by weight, 60 parts to 70 parts of superfine silver powder, 10 parts to 13 parts of glass powder, 1 part to 2 parts of lactose, 0.3 part to 0.5 part of penetrant, 7 parts to 10 parts of shellac, 1 part to 2 parts of polyethylene glycol, 4 parts to 6 parts of isopropyl alcohol, 5 parts to 7 parts of ethanol, 3 parts to 5 parts of xylene, 1 part to 2 parts of rosin, 2 parts to 3 parts of molecular sieves, 0.3 part to 0.6 part of sulfosalicylic acid, and 0.2 part to 0.4 part of cobalt naphthenate. According to the silver paste, the glass powder free of lead is used, and therefore the silver paste is environmentally friendly, low in melting point and good in cohesiveness. The natural shellac is adopted as an organic carrier of the environmentally-friendly printed circuit board conductive silver paste and thus the silver paste is not only good in adhesiveness but also environmentally friendly and healthy; by adding the molecular sieves, the silver powder can be dispersed easily and prevented from being agglomerated, and conductivity is good.