Process for dyeing protein fibers with a

Claim 1

A PROCESS FOR DYEING FIBERS SELECTED FROM THE CLASS CONSISTING OF NATURAL AND REGENERATING PROTEIN FIBERS WHICH COMPRISES IMMERSING SAID FIBERS IN AN AQUEOUS DISPERSION OF A WATER-INSOLUBLE DYESTUFF, WHICH DYESTUFF IS FREE FROM SULFONIC ACID AND CARBOXYLIC ACID GROUPS AND WHICH CONTAINS A REACTIVE GROUP WHICH IS CAPABLE OF REACTING WITH SAID FIBERS WHEREBY THE DYESTUFF IS ATTACHED TO SAID FIBERS BY A CHEMICAL BOND, AND WHICH DISPERSION HAS AN ACID PH OF LESS THAN 7; HEATING THE SAID AQUEOUS DISPERSION WITH SAID FIBERS THEREIN; ADDING A MEMBER SELECTED FROM THE CLASS CONSISTING OF ALKALI AND ALKALINE EARTH METHAL SALTS AND HYDROXIDES TO RAISE THE PH OF SAID AQUEOUS DISPERSION TO A HIGHER LEVEL OF FROM ABOUT 4.5 TO A T MOST ABOUT 8; FURTHER HEATING THE DISPERSION WITH THE FIBERS STILL IMMERSED THEREIN; AND THEREAFTER REMOVING AND FIBERS FROM THE DYEBATH, RINSING THE SAME IN WATER, AND DRYING THE SAME, WHEREBY REACTED AND DYED FIBERS ARE OBTAINED.