Effect of various polymer additives on the rheology and thixotropy of organic vehicles

In this study, the contents of ethyl cellulose (EC) as thickener in organic vehicle, which also acts as a binder, was examined using various control experiments; dibutyl phthalate (DBP) and dioctyl phthalate (DOP) were used as plasticizers, and acrylic resin (AR) was used as the thixotropic agent. In addition to thixotropic index, Bigham and Casson yield stress models were used for simulation, and the organic vehicle was dynamically simulated via the three interval thixotropy test; the viscosity recovery of the organic vehicle was investigated on the removal of shear stress. When the contents of the plasticizers, DBP and DOP, were 4 wt% and 6 wt%, respectively, the content of the thickener, EC, was 12 wt% and that of the thixotropic agent, AR, was 2 wt%, the comprehensive performance of the organic vehicle was greatly improved, especially in terms of thixotropy and recovery behavior. Our results demonstrate that the current organic vehicle is promising for the application of silver pastes used as inner electrodes in low-temperature co-fired ceramic (LTCC).