Supercritical extraction of binder and plasticizer with carbon dioxide and ethylene from BaTiO_3 multilayer ceramic capacitors

摘要

The thermal removal of binder from multilayer ceramic capacitors (MLCs) becomes progressively more difficult as the size of the components becomes larger for increased charge storage. An alternative strategy is to remove the binder by supercritical extraction. Because the binding phase often consists of mixtures of organic species, the degree of extraction of each organic constituent depends on the chemical nature of the supercritical fluid. In this paper, we present results for the degree to which poly(vinyl butyral) (PVB) and dioctyl phthalate (DOP) can be removed from MLCs by supercritical carbon dioxide, ethylene, and mixtures thereof. The supercritical fluids can readily extract the pure DOP plasticizer, whereas removal of the pure PVB is more difficult. When both organic components are present together with the ceramic, however, much less extraction occurs, which is attributed to interactions between the organic components and the ceramic.