PURPOSE: To improve the adhesion between the base paper and a polyester resin layer by coating the surface of the base paper with a polyester resin consisting essentially of polyethylene terephthalate, etc., and specifying the surface roughness after the coating layer is released.
CONSTITUTION: The surface of the base paper is coated with a polyester resin consisting essentially of polyethylene terephthalate or a composition obtained by dispersing a pigment in the resin to form a substrate for photographic printing paper. The average roughness Ra in the center line of the surface after the coating layer is released is controlled to ≥5000. The base paper surface is flame-treated to attain the roughness Ra when the substrate is produced, or the surface free energy of the base paper is increased to improve the wettability of the base paper with the molten resin. Consequently, a substrate for photographic printing paper is obtained without the adhesion being decreased with time especially under high-temp. and high-humidity conditions.
SATO TAKANORI
MIYOSHI TAKAHITO
TADA SUGIHIKO
KAWABATA YASUNARI
OBARA SHINICHIRO
