A decolorization method of a polyester fabric includes: providing a polyester fabric, in which the polyester fabric is a dyed polyester fabric and the polyester fabric is adhered with a dye and has a first L value; providing a first decolorizing solution and a second decolorizing solution, in which the first decolorizing solution contains a reductant and the second decolorizing solution contains an oxidant; and performing a decolorization process which includes: using one of the first decolorizing solution and the second decolorizing solution to decolorize one portion of the dye and using another one of the first decolorizing solution and the second decolorizing solution to decolorize another portion of the dye, so that a color of the dye is removed and the polyester fabric is white in color and has a second L value that is greater than the first L value.

A photocatalytic method of colored discharge printing for producing colorized patterns on textiles includes over dyeing textiles with illuminant dyes and ground shade dyes respectively, manufacturing patterned printing plates with hollow-out decorative patterns, applying a photocatalyst on the over-dyed textiles through the hollow-outs, using a photocatalytic method of colored discharge printing to produce localized discoloration of the ground shade while leaving the illuminant dyes on the textile which produces an effect of colorized patterns on the textiles. The method has the characteristics of being a simple process with a simple apparatus and has short processing, easy control and wide adaptability. The method eliminates the needs for printing pastes and expensive printing apparatus used in the complicated process in a conventional printing method.

A dye discharge composition exhibiting extended shelf life and/or pot life and high suitability for inkjet printing on dyed substrates, is disclosed. The composition comprises a reducing agent such as, for example, a sulfur-based reducing agent, and a chelating agent, such as a sodium salt of a polyamino carboxylic acid chelating agent. Use of the dye discharge composition in combination with a translucent colored composition and an optional opaque underbase composition, for forming an image on a dyed substrate is also disclosed. Processes for inkjet printing of an image on a dyed surface using the dye discharge composition, kits for use in such processes or an ink formulation containing same are also disclosed.

An example of a dye discharge fluid includes a water-soluble organic solvent, a heat activated reducing agent, and water. A pH of the dye discharge fluid is less than 7. The dye discharge fluid may be used with a colored pigmented inkjet ink, a white pigmented inkjet ink, and/or a colored textile fabric, and may be included in a fluid set and/or a printing kit.

The invention relates to a synergistically active composition which comprises a mixture of a sulfinic acid or a salt thereof and ascorbic acid or a salt thereof and the use of the composition as reducing agent. The reducing power of the composition of the invention is significantly higher than the reducing power of the single components.

The invention relates to a synergistically active composition which comprises a mixture of a sulfinic acid or a salt thereof and ascorbic acid or a salt thereof and the use of the composition as reducing agent. The reducing power of the composition of the invention is significantly higher than the reducing power of the single components.

The present invention relates to a composition for discharge printing of fabric, a discharge printing process for printing said composition to the fabric, the use of the composition for discharge printing and to a fabric treated with the composition in a discharge printing process according to the invention.

A discharge printing device includes an application unit configured to apply a reducing agent to fabric and a contact heating unit configured to subject a reducing agent-applied area to contact heating and satisfies any of the conditions (a1)-(c1) and (d1)-(e1): the conditions (a1)-(c1): in the contact heating, a heating temperature is 100 C. or more, and a heating time is 60 seconds or more; the conditions (d1)-(e1): the contact heating unit subjects the reducing agent-applied area to contact heating to accelerate a reduction reaction and subjects, after the acceleration of the reduction reaction, the reducing agent-applied area to contact heating to accelerate an oxidation reaction, or the discharge printing device further comprises a non-contact heating unit, and the non-contact heating unit subjects, after the acceleration of the reduction reaction, the reducing agent-applied area to non-contact heating to accelerate an oxidation reaction.

Provided herein is a method for forming an image on a dyed synthetic fabric, using a dye-discharge agent, the method is effected by printing an ink composition on the fabric and applying a dye-discharge agent essentially on the same area of the ink composition, wherein applying the dye-discharge agent is effected while the ink composition is still wet (uncured), prior to a curing of the image, and followed by curing the fully formed image, whereas the dye-discharge agent discharged the dye that migrated during the curing step, but not the dyed fabric.

A process of in situ forming a dye discharge reagent on at least a portion of surface of a dyed substrate, effected by applying two or more compositions comprising reactants on the substrate, such that the reactants undergo a chemical reaction on the substrate to form the reagent is provided herein, as well as a method for dye discharging a dyed substrate using the process of in situ forming a dye discharge reagent, and a dye discharge composition comprising said dye discharge reagent. In some embodiments of the invention, the reactants are thiourea and a peroxide, and the dye discharge reagent is formamidine sulfinic acid (FSA).