Abstract
Resin-coated paper (RC paper) which is manufactured by melt-extrusion of a coating of polyethylene resin onto both sides of the paper base is mainly used as a support for imaging materials such as photographic paper. The surface smoothness of RC paper is an important property and it is necessary to quantitatively define the surface smoothness. We thus analyzed the surface roughness of RC paper and sharp dents (pits) or “pear skin” generated on the surfaces of RC paper. We found that the surface roughness calculated by a flattening estimation using a leveling theory for a liquid coating corresponded well with the experimental values. Also we found that the observed density of surface pits agreed well with those obtained by using an index based on the flattening estimation model where the pits are related to deep vacancies which still remain on the surface of the base paper even after coating the base paper. These results support the validity of the flattening estimation model and the pit generation model where the pits are considered to be projections of the volume of deep vacancies remaining on the surface of the base paper. The pit estimation model can be widely applied by using the index correcting the elastic behavior of a resin.
