Ultrafine grinding of mica in organic medium for ink-jet printing process

Abstract

This work investigates the grinding of a mica powder in an organic medium in order to make the particle size compatible with the inkjet process using a high-energy ball mill. A detailed protocol leading to size reduction without altering structural properties of interest of this material has been successfully developed. Two steps are necessary, namely dry grinding and wet grinding in ethanol. The final particle size obtained was D90 = 1.9μm which is very close to the size requirement of the inkjet process related to the printing nozzle diameter (52μm). The mica morphology in the form of platelets was shown to be conserved by means of scanning electron microscope observations. X-ray diffraction confirmed that the mica did not undergo any change in its crystallographic structure. The decrease in particle size was revealed by the broadening and intensity drop of the diffraction peaks. Thermogravimetric analyses highlighted a shift of dehydroxylation reactions towards lower temperatures, which is also coherent with platelet size reduction.