Measurement of Water Vapor Transmission Rates by Using Cellulose Triacetate Substrate for Materials Difficult to Prepare a Thin Film

Abstract

A method for measuring the water vapor transmission rates of materials whose thin films are difficult to prepare is presented in this work. The method enables us to treat materials such as paints and adhesives, which are laminated on a cellulose triacetate film having a high permeability of water vapor and a high surface smoothness. The total permeability of a laminate is measured by the cup method and the permeability of the objective material is calculated by means of compensating the vapor transmission in the cellulose triacetate film. The predicted value of permeability for the objective material showed a good correlation with the value measured with a free membrane of the material.