Novel quinoneimine sulfur dye compositions, production thereof and use for dyeing cellulosic material

Abstract

Novel leuco sulfur dye compositions obtainable at current densities between 50 mA/cm 2 and 500 mA/cm 2 and a flow velocity in the range from 0.1 m/s to 2 m/s and preferably in the range from 0.1 to 0.4 m/s, their production and their use for dyeing cellulosic material.

1 . Leuco sulfur dye compositions obtainable at current densities between 50 mA/cm 2  and 500 mA/cm 2  and a flow velocity in the range from 0.1 m/s to 2 m/s.  
   
   
       2 . The leuco sulfur dye compositions according to  claim 1  which are obtainable at current densities between 50 mA/cm 2  and 150 mA/cm 2  and a flow velocity in the range from 0.1 to 0.4 m/s.  
   
   
       3 . Mixtures of different leuco sulfur dye compositions according to  claim 1 .  
   
   
       4 . A process for producing leuco sulfur dye compositions according to  claim 1 , which comprises starting at a concentration of 20 g/l and an initial current density of 0.5 mA/cm 2  and continuously increasing the concentration to 600 g/l and the current density to 500 mA/cm 2 .  
   
   
       5 . The process for producing leuco sulfur dye compositions according to  claim 4  which further comprises adding catalytic amounts of Bunte salts of the general formula R-S-SO 3 Na, where R represents organic repeat structural elements, or by catalytic addition of chemical reducing agents.  
   
   
       6 . The process according to  claim 4  wherein a massive plate electrode or a three-dimensional electrode is utilized in a divided electrolytic cell.  
   
   
       7 . The process according to  claim 4  wherein alkaline solutions of alkali metal salts are used as conducting electrolyte.  
   
   
       8 . The process for producing leuco sulfur dye compositions according to  claim 4  wherein electrolysis is effected at temperatures in the range from 20 to 135° C.  
   
   
       9 . The process for producing leuco sulfur dye compositions according to  claim 4  wherein electrolysis is effected at temperatures in the range from 20 to 95° C.  
   
   
       10 . The sulfur dye compositions according to  claim 1  wherein the sulfur dye is quinoneimine and wherefor a concentration of reduction equivalents between 150 Ah/kg and 534 Ah/kg based on 1 kg of dry solid sulfur dye is present when C.I. Sulfur Black 1 is used as dye raw material.  
   
   
       11 . The process for producing reduced quinoneimine sulfur dyes in their solid form by lowering the pH to ≦9 and/or drying the electrochemically reduced leuco quinoneimine sulfur dye solutions.  
   
   
       12 . The sulfur dye compositions according to  claim 1  wherein the sulfur dye is quinoneimine and wherefor a concentration of reduction equivalents between 75 Ah/kg and 225 Ah/kg based on 1 kg of dry solid dye is present when C.I. Vat Blue 43 is used as dye raw material.  
   
   
       13 . Dye preparations comprising leuco sulfur dye compositions according to  claim 1 .  
   
   
       14 . Solid dye preparations comprising leuco sulfur dye compositions having a water content ≦5% by weight based on the entire product.  
   
   
       15 . A process for dyeing and printing cellulosic material, which comprises utilizing leuco sulfur dye compositions according to  claim 1 .  
   
   
       16 . A process for dyeing cellulosic material, which comprises effecting the electrochemical reduction to produce leuco sulfur dye compositions according to  claim 1  directly in the dyebath.  
   
   
       17 . (canceled)  
   
   
       18 . The process for producing leuco sulfur dye compositions according to  claim 4  which further comprises adding catalytic amounts of Bunte salts of the general formula R—S—SO 3 Na, where R represents phenothiazone, thiazone, thianthrene or phenoxazone substructures, or by catalytic addition of chemical reducing agents which are selected from the group consisting of sodium dithionite, organic sulfinic acids, organic sugars and mixtures thereof.  
   
   
       19 . Solid dye preparations according to  claim 14  comprising leuco sulfur dye compositions having a water content ≦2% by weight based on the entire product.