Process of preparing translucent cellulosic sheeting

Claim 1

A PROCESS OF PREPARING A TRANSLUCENT CELLULOSIC SHEET, THE SURFACES OF SUCH SHEET HAVING A MATTE OR GROUND GLASS APPEARANCE OF EXCEPTIONAL REGULARITY AND UNIFORMITY WHICH COMPRISES TREATING THE SURFACE OF A PREFORMED CELLULOSIC SHEET FROM THE GROUP CONSISTING OF CELLULOSE ACETATE SHEETS, CELLULOSE PROPIONATE ACETATE SHEETS, CELLULOSE BUTYRATE ACETATE SHEETS, AND MIXED CELLULOSE ESTER SHEETS, WITH A LIQUID WHICH IS A SOLVENT FOR THE SURFACE OF THE SHEET AND WILL SOFTEN THE SURFACE, SAID LIQUID CONTAINING AS AN ESSENTIAL INGREDIENT AN AMMONIUM CHEMICAL WHICH IS SUBSTANTIALLY INSOLUBLE IN THE SOLVENTAND WHICH CHEMICALLY COMPOUND WILL DECOMPOSE TO GASEOUS PRODUCTS AT A TEMTERATURE BELOW A TEMPERATURE WHICH IS DESTRUCTIVE OF THE SHEETING BEING TREATED, TO OVERCOAT THE SHEET, SUBJECTING THE SHEET THUS OVERCOATED TO AN ELEVATED TEMPERATURE BETWEEN 140* F. AND 250* F. FOR A SUFFICIENT PERIOD TO CAUSE THE DECOMPOSITION OF A SUBSTANTIAL PROPORTION OF SAID CHEMICAL WITH GAS LIBERATION, WHEREBY SAID GAS LIBERATION CAUSES GAS HOLES IN THE OVERCOATED LAYER AND IMMEDIATELY ADJACENT SUBLAYERS OF SAID SHEET THEREBY PRODUCING A UNIFORM AND REGULAR ROUGHNESS ON THE SURFACE OF THE SHEET FOR SECURING OPACITY AND TRANSLUCENCY.