橡胶或塑料涂层织物 - 辊特性的测定 - 第2部分:测定每单位面积总质量的方法 涂层单位面积质量和每单位面积面积质量Rubber- or plastics-coated fabrics - Determination of roll characteristics - Part 2: Methods for determination of total mass per unit area, mass per unit area of coating and mass per unit area of substrate