Method for stripping color from keratinous material

Claim 1

THE PROCESS FOR STRIPPING COLOR FROM A KERATINOUS MATERIAL WHILE INCREASING ITS RESISTANCE TO ATTACH BY OXIDIZING AGENTS, REDUCING AGENTS, ACIDS AND ALKALIS AND PRESERVING SUBSTANTIALLY UNIMPAIRED ITS MECHANICAL PROPERTIES, WHICH COMPRISES TREATING THE KERATINOUS MATERIAL AT A TEMPERATURE ABOVE 60* C. AND A PH ABOVE 7, IN A LIQUID BATH CONTAINING 1% TO 100% OF THE WEIGHT OF THE KERATINOUS MATERIAL OF A REDUCING AGENT FOR KERATIN SELECTED FROM THE CLASS CONSISTING OF SULFOXYLATE FORMALDEHYDE COMPOUNDS, HYDROSULFITES AND FORMAMIDINE SULFINIC ACID, TO RUPTURE DISULFIDE CROSS LINKAGES OF THE KERATINOUS MATERIAL AND STRIP COLOR THEREFROM, SAID BATH ALSO CONTAINING MORE THAN 0.00045 MOL PER GRAM OF KERATINOUS MATERIAL OF AN ALKYLENE DIHALIDE, WHEREBY NEW STABLE ALKYLENE CROSS LINKAGES BETWEEN THE PEPTIDE CHAINS OF THE KERATIN ARE FORMED IMMEDIATELY UPON RUPTURE OF THE DISULFATE LINKAGES, AND THEREAFTER TREATING THE KERATINOUS MATERIAL AT A TEMPERATURE ABOVE 60* C. AND A PH OF 3 TO 7 IN A LIQUID BATH CONTAINING 1% TO 25% OF THE WEIGHT OF THE KERATINOUS MATERIAL OF A REDUCING AGENT SELECTED FROM THE CLASS CONSISTING OF ZINC HYDROSULFITE AND A MIXTURE OF ZINC SULFOXYLATE FORMALDEHYDE AND AN ACID FOR SRIPPING COLOR FROM THE KERATINOUS MATERIAL.