STRUCTURE FORMATION DURING DRYING OF COATING LAYER OF MAGNETIC PARTICULATE CONTAINING SOLVENT MIXTURE

It is important to understand the structure formation during drying of coating layers of magnetic particulate from the viewpoint of design of dryers and better quality of magnetic recording media, Drying characteristics of coating layers containing cyclohexanone and toluene were measured, and the change of intensity of reflected light at the layer surface was determined during drying. Then, surface and inside characteristics of dry layers were evaluated by gloss measurement and nitrogen adsorption. If the initial mass fraction of toluene was less than 50 wt% in the solvent mixture, toluene shortened the drying time and did not influence the gloss and the pore volume of dry layers. The influence of drying conditions on surface and inside characteristics of dry layers was qualitatively explained based on the model previously proposed by the authors.