抄録
For saving of energy and forest resources, there is a tendency to lessen the basis weight of paper. Basis weight of newsprint decreased from 52 g/m2 to 46 g/m2 by request of newsprint company about 10 years ago. Newsprint of 43 g/m2 is produced partly. In the case of fine paper, a decrease in basis weight brings about deterioration in the mechanical and optical properties that are the most important characteristics for end uses of paper. Roughness of paper surface makes it difficult to measure exactly the thickness of paper. The fact causes many problems for definition of mechanical properties of paper. Inhomogeneous structure through z direction has a strong influence on properties of paper when the thickness is decreased. The effect of paper thickness on Young's modulus and optical properties is disccussed. The importance of drying conditions of wet web on physical properties of paper is also described.
