US 12,344,991 B2
Decolorization method of polyester fabric
Te-Chao Liao, Taipei (TW); Jung-Jen Chuang, Taipei (TW); Zhang-Jian Huang, Taipei (TW); and Yun-Tong Lai, Taipei (TW)
Assigned to NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed by NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed on Jul. 15, 2022, as Appl. No. 17/865,925.
Claims priority of application No. 110133937 (TW), filed on Sep. 13, 2021.
Prior Publication US 2023/0082495 A1, Mar. 16, 2023
Int. Cl. D06L 4/13 (2017.01); D06L 4/15 (2017.01); D06L 4/22 (2017.01); D06L 4/30 (2017.01); D06L 4/70 (2017.01); D06L 4/75 (2017.01); D06P 1/673 (2006.01); D06P 5/13 (2006.01); D06P 5/15 (2006.01)
CPC D06L 4/13 (2017.01) [D06L 4/15 (2017.01); D06L 4/22 (2017.01); D06L 4/30 (2017.01); D06L 4/70 (2017.01); D06L 4/75 (2017.01); D06P 5/132 (2013.01); D06P 5/134 (2013.01); D06P 5/153 (2013.01); D06P 5/155 (2013.01); D06P 1/673 (2013.01); D06P 1/6735 (2013.01); D06P 1/67375 (2013.01); D10B 2331/04 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A decolorization method of a polyester fabric, comprising:
providing a polyester fabric, wherein 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, the first decolorizing solution containing a reductant, and the second decolorizing solution containing an oxidant; and
performing a decolorization process which includes;
heating the first decolonizing solution to a first decolorization temperature to decolorize one portion of the dye adhered on the polyester fabric, wherein the first decolonization temperature is between 135° C. and 180° C., first decolorization temperature is higher than a glass transition temperature of the polyester fabric, and the first decolorizing solution is maintained at a liquid phase in a pressure-resistant reaction tank;
discharging the first decolorizing solution from the pressure-resistant reaction tank;
heating the second decolorizing solution to a second decolorization temperature to decolorize another portion of the dye adhered on the polyester fabric, wherein the second decolorization temperature is between 135° C. and 180° C. the second decolonization temperature is higher than the glass transition temperature of the polyester fabric, and the second decolonizing solution is maintained at the liquid phase in the pressure-resistant reaction tank; and
discharging the second decolorizing solution from the pressure-resistant reaction tank;
wherein, after the decolorization process, the polyester fabric has a second L value that is greater than the first L value, and an intrinsic viscosity of the polyester fabric is decreased not more than 10%.