Abstract: A water-disintegrable support paper material largely formed of fibrous carboxymethylcellulose or carboxyethylcellulose having a degree of etherification of 0.1 to 1.0 and a degree of base saturation of 20% or more. A solution or dispersion of that paper has a pH of 5.0 to 8.0. There is also disclosed a composition for forming a water-disintegrable coat for coating on the support, the composition being a mixture of (a) at least one water-insoluble resin capable of forming a film having a saturation hygroscopicity less than 15% at a 90% relative humidity, (b) at least one water-soluble resin capable of forming film having a saturation hygroscopicity of 15% or more at a 90% relative humidity, and (c) a solvent in which both the resins (a) and (b) can dissolve.