Process of coating paper webs and product thereof

Claim 1

A PROCESS OF PRODUCING A NON-GLOSS PAPERBOARD SUITABLE FOR GLASS INK PRINTING WHICH COMPRISES APPLYING TO THE SURFACE OF FINISHED PAPERBOARD A COATING OF PLASTICIZING AGENT INAN AQUEOUS VEHICLE AND PLASTICIZING THE SAID SURFACE BY PASSING THE PAPERBOARD THROUGH ROLLS, THEREAFTER APPLYING TO THE PLASTICIZED SURFACE A COATING OF MINERAL MATTER AND STARCH IN AN AQUEOUS VEHICLE BY IMPRINTING, ONE OF SAID COATINGS CONTAINING A RESIN CAPABLE OF REACTING WITH STARCH TO INSOLUBILIZE IT AND THE OTHER OF SAID COATINGS CONTAINING A CATALYST FOR SAID INSOLUBILIZING REACTION, HEATING THE TREATED BOARD SO AS TO PRODUCE SAID REACTION AND INSOLUBLIZE THE STARCH THEREON, AND AFTERWARD PASSING SAID TREATED BOARD THROUGH A CALENDER STACK AND APPLYING TO THE COATED SURFACE THEREOF IN SAID CALENDER STACK A WATER SOLUTION OF A SEALING SUBSTANCE RESISTANT TO THE VEHICLE OF GLOSS PRINTING INKS IN QUANTITY SUFFICIENT TO SEAL THE PORES OF SAID STARCH-MINERAL MATTER COATING WITHOUT AFFECTING THE NON-GLASS CHARACTERISTICS THEREOF, THE SAID SEALING SUBSTANCE BEING A WATER SOLUBLE SUBSTANCE CHOSEN FROM A CLASS CONSISTING OF STARCH, METHYL CELLULOSE, CARBOXYMETHYL CELLULOSE, CARBOXYETHYL CELLULOSE, POLYVINYL ALCOHOL, VEGETABLE PROTEIN, SODIUM SILICATE AND ALIGNATE COMPOUNDS.