Process for the manufacture of coated paper

Claim 1

IN A PROCESS WHEREIN A PAPER IS COATED WITH AN AQUEOUS MIXTURE OF A MINERAL PIGMENT AND AN ALKALINE SALT OF A PROTEINACEOUS BINDER COLLOIDALLY DISPERSED THEREIN, SAID A2QUEOUS MIXTURE BEING SUBSTANTIALLY FREE OF MULTIVALENT METAL IONS AND THE PROTEIN THEREOF BEING CAPABLE OF REGENERATION UPON AN ACIDIFICATION OF SAID MIXTURE, AND THE COATING IS THEREAFTER DRIED BY HEATING; THE IMPROVEMENT COMPRISING TREATING SAID COATING PRIOR TO DRYING WITH A SOLUTION OF A VOLATILE LOWER ORGANIC ACID AND SHARPLY LOWERING THE PH OF THE COATING THEREBY REGENERATING SAID PROTEIN, FOLLOWED BY PRESSING SAID COATING IN FORMING CONTACT AGAINST A FINISHING SURFACE AND THEN HEAT DRYING TO EXPEL WATER AND EXCESS VOLATILE LOWER ORGANIC ACID THEREFROM.