A series of electron microscopic studies was carried out to make clear the surface fine structure of clay coated papers. The present work forms part of those studies and deals mainly with coating clays. The clays used are kaolin, sericite, roseki-clay and hydrated halloysite and were coated on a stock paper by using casein as a binder.
The results obtained are as follows :
(1) The one stage replica method, which was carried out by evaporating carbon an leaf, was found to be the most suitable technique for the purpose of this case.
(2) The surface of clay handcoated papers was observed to consist of the clay layers parallel to paper surfaces. And it was found that their fine structure depends largely upon the shape and size of clay particles.
(3) By comparing the surface of non-supercalendered coated papers with those of supercalendered coated papers, the effect of supercalendering was found to vary corresponding to the clays used.