PCC filler composition for improved printability of supercalendered papers

Abstract

A method of blending a fine precipitated calcium carbonate (PCC) filler with larger PCC, the resulting blend to be used alone or in conjunction with a ground carbonate, clay or other filler, resulting in improved porosity by the lowering of the porosity of supercalendered paper, thereby imparting improved and offset printability. The fine PCC can be ultrafine PCC filler which then is blended with other fillers including but not limited to pigments. These fillers which are blended with the fine PCC include commercial and experimental PCC and commercial clays. Ultrafine PCC has agglomerates of small, discrete particles. Ultrafine PCC for use in the invention has a specific surface area of about 20 m2/g as measured by BET gas adsorption. As measured by a sedigraph, the average size of these agglomerates is from 0.4 to 1.1 microns.

Dependencies are inferred from the claim text.