CALCINED KAOLIN CLAY FILLER PIGMENT FOR ENHANCING OPACITY ANDPRINTING PROPERTIES OF NEWSPRINT AND MECHANICAL PAPERS

摘要

A low-abrasion calcined kaolin opacifying pigment composed of particles in the size range of about 70 to 84% by weight finer than 2 microns and having a color defined by Hunter Trisitimulus values of "L" within the range of 92 to 94, "a" within the range of +1.0 to +2.2 and "b" within the range of +6.4 to +7.5. The pigment is produced by novel wet processing including high solids degritting of a high iron, high titania content Tertiary kaolin without conventional fractionation, bleaching and dewatering to isolate a fine particle size fraction, followed by spray drying, pulverization, calcination and repulverization.