Abstract: In order to measure and value the moisture transfer within the fabric used in the clothing under stead state. Three-step method were employed to determine the water vapor resistance of the whole apparatus, the water vapor resistance of the air layer 1 upon fabric surface and the water vapor resistance of the air layer 2 between the fabric’s lower surface and the water surface. The effective moisture diffusion coefficient in air layer 2 was determined by the regressive method, and then calculated the effective moisture diffusion coefficient of fabric on the condition of air layer exists. This method can effectively avoid the influence of the air layer on the test accuracy of measuring water vapor permeability of fabrics. The test results can reflect the mass transfer characteristics of the fabrics and provided a experimental basis for the fabric comfort study.

Key words: diffusivity, moisture cup method, fabric, moisture resistance