Journal of Korea TAPPI ISSN:0253-3200(Print) 펄프종이기술

High solid coating color is very attractive for practical paper coating applications to reduce the energy consumption of the entire coating process. However, when a large amount of calcium carbonate pigment was used, it has been difficult to control the water retention, the coating amount and the runnability of coating color. In this study, the surface properties and printability of the coated paper were analyzed by applying rheology modifier as well as viscoelastic modifier in order to improve the fluidity of the coating color of 68% and 71% solids contents. As a result, both the low shear viscosity and the high shear viscosity of the coating color for top-coating were improved by the application of the viscoelastic modifier regardless of the conditions of coating formulation and the solid content. When the solid content was increased from 68% to 71%, it was confirmed that the combination of the rheology modifier and the viscoelastic modifier can reduce or eliminate the use of starch and clay while maintaining low shear viscosity. The high shear viscosity tended to increase when the solids content increased to 71%, but it was confirmed that the application of viscoelastic modifier could reduce the high shear viscosity. In addition, when the clay was excluded and the solid content was increased, the effect of improving the smoothness, paper gloss, printability, ink set-off and ink trapping of the coated paper were obtained by using the viscoelastic modifier. Ultimately, when the solids content of the coating color was increased from 68% to 71%, it was possible to improve not only the physical properties and printability of the coated paper but also the energy consumption.