US 12,275,826 B2
Polyester resin using recycled bis(2-hydroxyethyl) terephthalate and article including same
Da-Young Hwang, Gyeonggi-do (KR); Ji-Hun Kim, Gyeonggi-do (KR); Kwang-Woo Park, Gyeonggi-do (KR); Yoo Jin Lee, Gyeonggi-do (KR); and Joong Ki Lee, Gyeonggi-do (KR)
Assigned to SK CHEMICALS CO., LTD., Gyeonggi-do (KR)
Appl. No. 18/569,120
Filed by SK CHEMICALS CO., LTD., Gyeonggi-do (KR)
PCT Filed Mar. 3, 2023, PCT No. PCT/KR2023/002933
§ 371(c)(1), (2) Date Dec. 11, 2023,
PCT Pub. No. WO2023/171986, PCT Pub. Date Sep. 14, 2023.
Claims priority of application No. 10-2022-0029483 (KR), filed on Mar. 8, 2022.
Prior Publication US 2024/0327602 A1, Oct. 3, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. C08J 11/24 (2006.01); C08G 63/183 (2006.01)
CPC C08J 11/24 (2013.01) [C08G 63/183 (2013.01); C08J 2367/02 (2013.01)] 12 Claims
 
1. A polyester resin, which comprises recycled bis(2-hydroxyethyl) terephthalate obtained through the depolymerization of waste polyester, wherein the recycled bis(2-hydroxyethyl) terephthalate has a peak area fraction of bis(2-hydroxyethyl) terephthalate of 96% or more and a peak area fraction of 2-hydroxyethyl[2-(2-hydroxyethoxy)ethyl] terephthalate of 2.5% or less, when measured by high-performance liquid chromatography (HPLC),
wherein the polyester resin has a third thermal resistance index of 2.6 or less as calculated from the following Equation (3):
Third thermal resistance index=first thermal resistance index+second thermal resistance index  (3),
wherein the first thermal resistance index is calculated from the following Equation (1):

OG Complex Work Unit Math
in Equation (1), DEG1, DEG2, and BHET0 are each the peak area fraction (%) of 2-hydroxyethyl[2-(2-hydroxyethoxy)ethyl] terephthalate, bis[2-(2-hydroxyethoxy)ethyl]benzene-1,4-dicarboxylate, and bis(2-hydroxyethyl) terephthalate, when the recycled bis(2-hydroxyethyl) terephthalate is measured by high-performance liquid chromatography (HPLC), and rBHET is the weight fraction (%) of recycled bis(2-hydroxyethyl) terephthalate in the polyester resin,
wherein the second thermal resistance index is calculated from the following Equation (2):
second thermal resistance index=(G/A)×0.32+0.83  (2),
in Equation (2), G and A are each the number of moles of glycol and the number of moles of diacid in the monomers constituting the polyester resin, and G/A is the mole ratio of glycol to diacid.