Photocatalytic method of discharge printing for producing colorful patterns on previously dyed textiles

A photocatalytic method of discharge printing for producing colorful patterns on previously dyed textiles consisting of the following steps:

• a) dye textiles with illuminant dyes to obtain dyed textiles;
• b) over dye the dyed textiles with ground shade dyes to obtain over-dyeing textiles;
• c) closely integrate hollow-outs patterned printing plates and the over-dyeing textiles, or fix the printing plates on one side or both sides of the textiles;
• then apply a photocatalytic matter on the hollow-outs of the patterns wherein the photocatalytic matter is selected from one of the group consisting of a solution, a colloid and a white paste containing a photocatalyst, wherein the concentration of the photocatalytic matter is 0.10 g/L˜10.00 g/L, the pH value is 2˜12;
• and the photocatalyst is potassium persulfate,
• d) put the patterned printing plates and the over-dyeing textiles in a sealed container with a light source, and open the light source followed by light irradiating the over-dyeing textiles vertically and uniformly through the hollow-outs of the patterned printing plates;
• then treat the textiles by photochemical reaction at temperatures ranging from 5° C. to 70° C., and for processing times of 1˜120 minutes, wherein textiles with single or double sided colorized patterns which have a different shade to the over-dyeing textiles are obtained,
• e) wash the textiles with single or double sided colorized patterns at room temperature and dry them to obtain textiles with colorized patterns.