Patent ID: 6942919
Filing Date: 2005-09-13
Classification: D21H,Y10T

Abstract:
1. A coated paper sheet comprising a substrate paper sheet and a coating layer, formed on at least one surface of the substrate paper sheet and comprising a pigment and a binder, wherein, the substrate paper sheet is one sizepressed with a sizing agent comprising an oxidized starch; the pigment in the coating layer comprises kaolin particles having an average particle size of 0.3 to 1.5 μm and satisfying the requirement represented by the equation (1): wherein L represents a major axis of the kaolin particles and W represents a minor axis of the kaolin particles; the binder in the coating layer comprises both (a) a copolymer having a glass transition temperature of 10 to 60° C. and a single phase structure and (b) a synthetic polymeric compound having a core-shell composite structure and satisfying the requirements represented by the inequalities (2) and (3); and  −10° C. Tg 2 <100° C.  (3) wherein Tg 1 represents a glass transition temperature of a core segment of the synthetic polymeric compound, and Tg 2 represents a glass transition temperature of a shell segment of the synthetic polymeric compound; the surface of the coating layer exhibits a 75 degree specular glossiness of 50% or more, determined in accordance with Japanese Industrial Standard Z8741-1997; and the coated paper sheet exhibits an air permeability of 7000 seconds or less, determined in accordance with Japanese Industrial Standard P8117-1998 and a clark stiffness of 12 cm or more in the transverse direction of the coated paper sheet.