Changing the color or dyed textile substrates

Abstract

The present invention relates to a process for obtaining color changes on dyed textile substrates by treating the dyed textile substrates with an electrochemically generated aqueous solution of reducing or oxidizing agents, which comprises controlling the cell current in such a way that the solution, when in contact with the dyed textile substrate, has a suitable redox potential to obtain the color change.

1 . A process for obtaining color changes on dyed textile substrates by treating the dyed textile substrates with an electrochemically generated aqueous solution of reducing or oxidizing agents, which comprises controlling the cell current in such a way that the solution, when in contact with the dyed textile substrate, has a suitable redox potential to obtain the color change.  
     
     
         2 . The process of  claim 1 , wherein the aqueous solution of reducing or oxidizing agent is generated in an electrolytic cell which is constructed as a flowthrough cell and which communicates directly with a treatment assembly into which the aqueous solution containing the reducing or oxidizing agent is pumped and in which the color change on the dyed textile substrate is generated.  
     
     
         3 . The process of  claim 1 , wherein the aqueous solution of reducing or oxidizing agent is generated in an electrolytic cell which is constructed as a treatment assembly in which the color change on the dyed textile substrate is generated.  
     
     
         4 . The process of  claim 1 , wherein the redox potential is +100 to +2000 mV in the case of oxidations and −300 to −1800 mV in the case of reductions.  
     
     
         5 . The process of  claim 1 , wherein inorganic reducing or oxidizing agents are used.  
     
     
         6 . The process of  claim 1 , wherein the reducing agent used is cathodically generated from a reversible redox system.  
     
     
         7 . The process of  claim 6 , wherein the reductive redox system used comprises 
 cathodically generated metal complexes with inorganic or organic ligands and in which the metal is present in a low, reduced, valency state,    substituted anthraquinone compounds,    tin(II) compounds, in alkaline solutions, or    dithionite generated by cathodic reduction, in weakly acidic solution.    
     
     
         8 . The process of  claim 1 , wherein the oxidizing agent used is anodically generated from a reversible redox system.  
     
     
         9 . The process of  claim 8 , wherein the oxidative redox system used comprises 
 halogen-oxygen compounds,    metal complexes with inorganic or organic ligands and in which the metal is present in a high oxidized, valency state,    cycloaliphatic, heterocyclic or aromatic compounds which contain an NO, NOH or HNR—OH group, or    hydrogen peroxide generated cathodically by oxygen reduction or other electrochemically regenerable inorganic or organic peroxo compounds.    
     
     
         10 . The process of  claim 6 , wherein the redox systems are used in the concentration range from 0.1 mmol/l to 5 mol/l.  
     
     
         11 . The process of  claim 3 , wherein the redox potential is +400 to +1600 mV in the case of oxidations and −400 to −1200 mV in the case of reductions.  
     
     
         12 . The process of  claim 6 , wherein the reductive redox system used comprises 
 cathodically generated metal complexes with inorganic or organic ligands and in which the metal is present in iron(II) or tin(II) complexes with inorganic or organic ligands,    substituted anthraquinone compounds,    hexahydroxystannite in alkaline solutions, or    dithionite generated by cathodic reduction, in weakly acidic solution.    
     
     
         13 . The process of  claim 6 , wherein the reductive redox system used comprises 
 cathodically generated metal complexes with inorganic or organic ligands and in which the metal is present in iron(II) complexes containing a 2-hydroxyethyl group or a polyhydroxycarboxylic acid in the ligand,    1,2-dihydroxyanthraquinone or anthraquinonesulfonic acids,    hexahydroxystannite in alkaline solutions, or    dithionite generated by cathodic reduction, in weakly acidic solution.    
     
     
         14 . The process of  claim 8 , wherein the oxidative redox system used comprises 
 hypochlorite and hypobromite,    metal complexes with inorganic or organic ligands and in which the metal is present in a metal complexes of iron(II) and of manganese(III) with inorganic or organic ligands,    2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) and violuric acid or    hydrogen peroxide generated cathodically by oxygen reduction or other electrochemically regenerable inorganic or organic peroxo compounds.    
     
     
         15 . The process of  claim 8 , wherein the oxidative redox system used comprises 
 hypochlorite and hypobromite,    metal complexes with inorganic or organic ligands and in which the metal is present in a metal complexes of iron(III) 2,2′-dipyridyl, Fe(III) hexacyanoferrate and Mn(III) transcyclohexane-1,2-diamine-N,N,N′,N′-tetraacetate,    2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) and violuric acid or    hydrogen peroxide generated cathodically by oxygen reduction or other electrochemically regenerable inorganic or organic peroxo compounds.    
     
     
         16 . The process of  claim 9 , wherein the redox systems are used in the concentration range between 1 mmol/l and 0.1 mol/l.