Influence of pigment and binder composition on the dynamic water penetration and dried structure of precoating layers for double-coated paper

The influence of precoating colors on the dynamic water penetration behavior of double-coated paper was investigated using a laboratory coater equipped with two coating heads. Emphasis was placed on the effects of the pigment combination and binder type on dynamic water penetration. In addition, the latex content on the surface of the coating layer was examined by UV absorbance analysis. The amount of water that penetrated the base paper was found to be proportional to the square root of the contact time between the coating color and the base paper, regardless of the pigments and binders used. When a large amount of pigment with a fine particle size was used, or the starch binder content was increased, the low shear viscosity of the coating color increased, and the amount of water penetration into the base paper decreased. The UV absorbance analysis showed that higher water holding in the coating color increased the latex content on the surface of the coating layer. Increasing the viscosity or water retention of the coating color was found to reduce the amount of binder migration into the base paper.