US 12,258,453 B2
Method for improving hue of recycled bis-2-hydroxylethyl terephthalate by using ionic liquids
Te-Chao Liao, Taipei (TW); Jung-Jen Chuang, Taipei (TW); Wei-Sheng Cheng, Taipei (TW); Zhang-Jian Huang, Taipei (TW); and Yu-Ti Tseng, Taipei (TW)
Assigned to NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed by NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed on Jun. 24, 2022, as Appl. No. 17/808,893.
Claims priority of application No. 110131575 (TW), filed on Aug. 26, 2021.
Prior Publication US 2023/0060362 A1, Mar. 2, 2023
Int. Cl. C08J 11/24 (2006.01); B01D 9/00 (2006.01); B01D 15/12 (2006.01); B01D 15/16 (2006.01); C07C 67/56 (2006.01); C08J 11/28 (2006.01)
CPC C08J 11/24 (2013.01) [B01D 9/0013 (2013.01); B01D 15/12 (2013.01); B01D 15/161 (2013.01); C07C 67/56 (2013.01); C08J 11/28 (2013.01); B01D 2009/0086 (2013.01); C08J 2367/02 (2013.01); Y02W 30/62 (2015.05)] 9 Claims
OG exemplary drawing
 
1. A method for improving hue of recycled bis-2-hydroxylethyl terephthalate by using ionic liquids, comprising:
implementing a preparation operation, which includes providing a recycled polyester fabric, the recycled polyester fabric containing impurities;
implementing a de-polymerization operation, which includes using a chemical de-polymerization liquid to chemically de-polymerize the recycled polyester fabric to form a de-polymerization product, the de-polymerization product including the bis-2-hydroxylethyl terephthalate (BHET) and the impurities;
implementing a purification operation, which includes mixing the de-polymerization product with water to form an aqueous phase liquid; and then dispersing an ionic liquid impurity adsorption material in a solid state into the aqueous phase liquid, so that the ionic liquid impurity adsorption material adsorbs the impurities originally present in the recycled polyester fabric,
wherein the ionic liquid impurity adsorption material includes a substrate and the ionic liquids grafted onto the substrate, the substrate is a granular material and has an average particle size of between 57.4 micrometers and 71.0 micrometers,
wherein, in the ionic liquid impurity adsorption material, a grafted quantity of the ionic liquids grafted onto per gram of the substrate is between 106 and 1020,
wherein, in the purification operation, a weight ratio of the ionic liquid impurity adsorption material relative to the aqueous phase liquid is in the range of 1:10-100, the aqueous phase liquid is heated to a liquid temperature of between 85° C. and 150° C., and the ionic liquid impurity adsorption material adsorbs the impurities under the liquid temperature; and
implementing a separation operation, which includes using a centrifugal method and/or a filtering method to collect the ionic liquid impurity adsorption material in the solid state that are dispersed in the aqueous phase liquid.