Study of Coating Structure Affecting Print Mottle-I. Development of the Method of Coating Structure Analysis and Application to Print Mottle.

Abstract

The surface latex concentration, Croda ink density and coat weight were measured by the spectrophotometer to analyze Croda ink mottle phenomenon. For one-side coated paper, coat weight was obtained by measuring the transmitted visible light intensity based on the absorption of visible light by SB-latex treated with 0504 in coating layer. For both-side coated paper, the reflected visible light intensity with a certain wavelength was used to measure coat weight. Relationship between surface latex concentration and coat weight greatly depended on the clay/ CaCO3 pigments ratio. The correlation became more significant as the amount of CaCO3 increased. Croda ink density highly correlated with coat weight. The more the coat weight, the less the Croda ink density. The relationship between the line gradient for the regression analysis between Croda ink density and coat weight showed the best relationship to Croda ink mottle.