1987 Volume 41 Issue 3 Pages 255-265
Calcium carbonates, which contribute the improvement of the optical properties and printabilities to paper, are generally used for paper coating pigments as well as kaolin clay.
In this paper, the surface smoothness of coated paper with various calcium carbonates have been evaluated by two instruments.
One is the instrument which measures the value in terms of Rp (printing roughness). The Rp value determined by the optical contact method, represents the surface smoothness of paper in contact with prism surface under the pressure.
The other is the instrument which measures the three dimensional roughness by stylus method.
The results obtained with the two instruments represent that coated paper with cubical calcium carbonate having 11.5m2/g BET specific surface area showed the highest smoothness among them, including those coated with kaolin clay which was prepared for comparison purpose. Rp value has the positive correlation with the average particle size of calcium carbonate, and the gloss of coated paper.
