Treatment of artificial protein threads with cyanic ions

Claim 1

IN A PROCESS FOR THE PRODUCTION OF ARTIFICIAL PROTEIN THREADS COMPRISING EXTRUDING A SOLUTION OF A PROTEIN SELECTED FROM THE GROUP CONSISTING OF LACTIC CASEIN AND PEANUT PROTEIN INTO AN AQUEOUS ACID COAGULATING BATH AND SUBJECTING THE RESULTANT FRESHLY-EXTRUDED THREAD TO A HARDENING TREATMENT TO INCREASE RESISTANCE TO COLD WATER IN A BATH CONTAINING FORMALDEHYDE AND AT LEAST ONE METAL SALT FROM THE GROUP CONSISTING OF ALUMINUM SULPHATE AND SODIUM SULPHATE TO RENDER IT RESISTANT TO COLD WATER, THE METHOD FOR STABILIZING THE THREAD AGAINST THE ACTION OF HOT WATER AND HOT DILUTE ACIDS WHICH CONSISTS ESSENTIALLY IN THE STEPS OF TREATING THE HARDENED THREAD WITH AN AQUEOUS SOLUTION CONTAINING CYANIC IONS, AND REMOVING EXCESS SOLUTION, KEEPING ON THE HARDENED THREAD AFTER SAID REMOVAL STEP, THAT AMOUNT AND SUBSTANTIALLY ONLY THAT AMOUNT OF CYANIC IONS WHICH IS THE CHEMICAL EQUIVALENT OF THE ACIDIC AMINO ACID RESIDUES OF THE PROTEIN; AND DRYING THE THUS-TREATED THREAD AT AN ELEVATED TEMPERATURE.