Window dyed casing

Claim 1

IN THE PROCESS WHEREIN CASING IS MANUFACTURED BY THE EXTRUSION OF SEAMLESS TRANSPARENT TUBING FROM CELLULOSE DERIVATIVE AND WHICH EXTRUDED TUBING IS THEREAFTER PASSED, IN SUCCESSION, THROUGH A SERIES OF REGENERATING, WASHING AND PLASTICIZER-CONTAINING BATHS, THE STEPS WHICH COMPRISE, AFTER THE SEAMLESS REGENERATED CELLULOSE TUBING LEAVES THE FINAL WASH IN WHICH REGENERATING MEDIUM IS REMOVED THEREFROM, PASSING THE WET TUBING IN COLLAPSED CONDITION THROUGH DYE SOLUTION WHILE MASKING A SELECTED PORTION OF ITS OUTER SURFACE TO PREVENT DYEING OF SAID PORTION, REMOVING EXCESS DYE SOLUTION FROM THE OUTER SURFACE OF THE TUBING IN A TIME INTERVAL BEFORE THE DYE PERMEATES TO THE INNER SURFACE THEREOF SO AS TO LIMIT THE DYEING EFFECT TO THE UNMASKED OUTER SURFACE PORTION OF THE TUBULAR CASING, AND THEREAFTER PASSING THE TUBING INTO A BATH CONTAINING PLASTICIZER.