| abstract |
A water-metachromatic sheet has a support with a porous layer containing a binder resin with dispersed fine-particle silicic acid. The sheet is capable of rendering different transparency between water absorbed and unabsorbed states. The support is a cloth having a weight per unit area of 30 gm 2 to 1,000 gm 2 , the fine-particle silicic acid is contained in an amount of from 1 gm 2 to 30 gm 2 , and the fine-particle silicic acid is incorporated in an amount from 0.5 to 2 parts by weight based on 1 part by weight of the binder resin. |