Low temperature colouring method

Abstract

The present invention relates to a method of colouring polymer substrates at low temperatures. The method comprises subjecting the polymer substrate that is to be coloured to a colouring liquor comprising a solvent in which the colourant has a high solubility and then adding a solvent in which the colourant has a low solubility, typically water.

1 . A method of colouring a polymer substrate, the method comprising:
 a) subjecting the polymer substrate to a colouring liquor at a temperature T1, T1 being below 100° C., said colouring liquor comprising at least one colourant dissolved in a first solvent system to provide the polymer substrate wetted with the colouring liquor;   b) adding a second solvent system to the polymer substrate wetted with the colouring liquor, without raising the temperature above a temperature T2, T2 being below 100° C., to provide the coloured polymer substrate wetted with a mixture of the first solvent system and the second solvent system; and   c) separating the coloured polymer substrate from the mixture of the first and second solvent systems and any remaining colourant;   
       wherein the colourant or colourant dye is more soluble in the first solvent system than in the second solvent system. 
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . A method of  claim 1 , wherein the second solvent system is water. 
     
     
         5 . A method of  claim 1 , wherein the first solvent system and the second solvent system are miscible. 
     
     
         6 . (canceled) 
     
     
         7 . A method of  claim 1 , wherein the first solvent system is a polar organic solvent or a mixture of polar organic solvents. 
     
     
         8 . A method of  claim 7 , wherein the first solvent system comprises acetone. 
     
     
         9 . A method of  claim 7 , wherein the first solvent system comprises a solvent selected from glycerol, ethylene glycol diacetate (EGD), triethylene glycol monomethyl (TGM), dipropylene glycol methyl ether (DME) and 1-methoxy-2-propanol. 
     
     
         10 . A method of  claim 1 , wherein the polymer substrate is a fibre substrate. 
     
     
         11 . A method of  claim 10 , wherein the fibre substrate comprises fibres selected from: a polyester, nylon, a polyurethane, wool, silk, cotton or a mixture thereof. 
     
     
         12 . A method of  claim 11 , wherein the fibre substrate comprises polyester fibres. 
     
     
         13 . A method of  claim 12 , wherein the fibre substrate comprises polyester fibres and at least one fibre selected from cotton, regenerated cellulose, wool, silk, polyamide, a different polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere and a polyurethane. 
     
     
         14 . A method of  claim 13 , wherein the fibre substrate comprises a material that is a blend of polyester fibres and at least one fibre selected from cotton, regenerated cellulose, wool, silk, polyamide, a different polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere and a polyurethane. 
     
     
         15 . A method of  claim 14 , wherein the fibre substrate comprises a first material that comprises polyester fibres and a second material that comprises at least one fibre selected from cotton, regenerated cellulose, wool, silk, polyamide, a different polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere and a polyurethane. 
     
     
         16 . A method of  claim 15 , wherein the fibre substrate is a whole garment. 
     
     
         17 . A method of  claim 1 , wherein the ratio of the total volume of the first solvent system to the total volume of the second solvent system is in the range 1:2 to 1:20. 
     
     
         18 . A method of  claim 16 , wherein the ratio of the total volume of the first solvent system to the total volume of the second solvent system is in the range 30:70 to 10:90. 
     
     
         19 . A method of  claim 1 , wherein the weight ratio of the polymer substrate to the first solvent system is in the range from 3:1 to 1:3. 
     
     
         20 . A method of  claim 1 , wherein the at least one colourant is at least one dye. 
     
     
         21 . A method of  claim 20 , wherein the at least one dye is a disperse dye. 
     
     
         22 . A method of  claim 1 , wherein the method comprises dissolving the at least one colourant in the first solvent system to form the colouring liquor 
     
     
         23 . A method of  claim 1 , wherein the colouring liquor does not comprise a dispersing agent. 
     
     
         24 . (canceled)