| abstract |
A foamed, opacifying element is prepared to have a light-blocking value (LBV) of at least 4. A method is carried out in a specific order with a unique series of steps including: providing a unique foamable aqueous composition; aerating that foamable aqueous composition to a foam density of at least 0.1-0.5 g/cm 3 ; disposing the foamed aqueous composition onto a surface of a porous substrate; drying the foamed aqueous composition without substantial curing of the binder material therein, to provide a dry foamed composition on the surface, without substantial curing; densifying the dry foamed composition to provide a dry opacifying layer in a foamed, opacifying element; and curing the dry opacifying layer in the foamed, opacifying element. |