Tailor-Made Silica and Alumina for Inkjet Media Coatings

摘要

The optical properties and printability of modern, micropor-ous inkjet media is strongly controlled by the type of the pigments used inside the coating. It is well known that coatings based only on commodity pigments like clay or calcium carbonate cannot meet today's requirements. The use of amorphous, synthetic silica or alumina is not only setting the limits of conventional coatings, but is also making functional high performance pigments the key to meeting current and future requirements. These modern materials provide special pore structures and surfaces for the adsorption of dyes and/or color pigments resulting in properties like excellent image density, outstanding resolution and instant drying. This paper gives an overview over the physical-chemical properties of special synthetic pigments and their relation to the parameters of the coating process and the resulting optical properties of the media. Such aspects as the pigment composition (silica, alumina, mixed oxides), the pigment formation process (fumed, precipitated), the particle size and structure, the dispersion process and the formation of the coating formulation are correlated with media properties like gloss, ink adsorption, and image quality.