Conventional thinking regarding the optical characteristics for coated paper is the design characteristics of the coating pigments are critical. Key design characteristics are the average particle size, the particle size distribution and the particle shape. If these factors can be combined more effectively in the coated layer they can give improved characteristics, namely, the diffusion of light whereby improving opacity and improving gloss of the coating.
Optical synergy effects start to become evident through the combination of calcium carbonate and kaolin in which the unique pigment design of each component is different and the result is a complementary effect on coated paper properties.
Through this research we can understand some of the synergy effects in coated paper when blending coating PCC and high aspect ratio kaolin. The combination of shape engineered pigments leads to synergies that are not evident when simply using size engineered pigments.