Effect of molecular weight of ethyl cellulose on copper electronic pastes for multilayer ceramic capacitors (MLCC)

Organic vehicle carbon residue after sintering of copper-terminated electronic pastes for multilayer ceramic capacitors (MLCC) under nitrogen atmosphere has been a challenge. In this work, thermal degradation of ethyl cellulose with different molecular weights was investigated using TG-FTIR, and it is found that the volatilization rate of CH 4 and CO 2 of ethyl cellulose rose with the increase of molecular weight, and the residual rate of ethyl cellulose with 5.0 × 10 4 was only 1.29 % at 800 °C. The molecular weight of ethyl cellulose also shows a great influence on the rheological properties of copper terminal paste, the phase angle of copper pastes gradually decreases with the increasing molecular weight of ethyl cellulose, from viscous liquid to elastic solid. For the copper terminal paste, which is prepared by ethyl cellulose with molecular weight between 4.6 × 10 4 and 5.0 × 10 4 , the end termination morphology is good and the densification of the sintered copper paste is more than 99.5 %, which has satisfactory rheological and sintering properties. This work clarifies the effect of thickener on electronic paste and provide guidance for the design of organic vehicle and electronic paste.