Unique Light Weight Coating to Generate a Coated Paper with Low Sheet Gloss But Extremely High Print Gloss and its Mechanism for Such Exceptional Performance, 2001 Coating Conference Proceedings

Zhenwen Fu and James T. Brown--This paper presents a theoretical basis, computer simulations, and lab and pilot trial results for a new approach in making matte and dull papers. The approach is to double coat. The first coat (base coat) provides a reasonably smooth surface and porosity and the second coat (top coat) is a very light weight less than mono-layer coat. This second coat provides the controlled roughness to be within less than one micron relative to the smooth base coat. Such roughness is enough to yields less than 30 units of sheet gloss. Both solution polymers and latex polymers in the light weight top coat sizes or seals the base coat to some degree. The sizing effect of the topcoat and the base coat formulation and structure control the porosity beneath the thin rough layer. Paper produced by this approach has high glossing resistance to calendering and extremely high print delta gloss. The remaining challenge of this approach is to balance delta gloss, set off and appearance through a proper matching of the base coat and top coat.