The tortuosity factor is given as the ratio of the theoretical absorption coefficient calculated from the cylindrical model to the observed absorption coefficient by the Bristow method. A new formula to give mean pore radius of paper is derived by taking account of the liquid absorption into every pore size according to the Lucas-Washburn equation.
The liquid absorption model is proposed to allow calculation of transferred liquid volume to paper in an arbitrary time from initial absorption through saturation. The results of the transfer tests of ethyl alcohol to four kinds of papers by the Bristow method show good agreement between the observed and calculated liquid volumes transferred to the papers.
For other non-aqueous liquids which show the same V(t) vs. (7L tlrqY/2 relationship in the liquid transfer tests to a particular paper as ethyl alcohol, it is assumed that the liquid volume transferred to the paper in an arbitrary time can be estimated by means of the model.