US 12,221,724 B2
Recycled polyester filament and preparation method therefor
Hongwei Fan, Wujiang (CN); Shanshui Wang, Wujiang (CN); Lili Wang, Wujiang (CN); and Fangming Tang, Wujiang (CN)
Assigned to JIANGSU HENGLI CHEMICAL FIBRE CO., LTD., Wujiang (CN)
Appl. No. 17/789,792
Filed by JIANGSU HENGLI CHEMICAL FIBRE CO., LTD., Wujiang (CN)
PCT Filed Jun. 12, 2020, PCT No. PCT/CN2020/095729
§ 371(c)(1), (2) Date Jun. 29, 2022,
PCT Pub. No. WO2021/135085, PCT Pub. Date Jul. 8, 2021.
Claims priority of application No. 201911410774.0 (CN), filed on Dec. 31, 2019.
Prior Publication US 2023/0040916 A1, Feb. 9, 2023
Int. Cl. D01F 6/62 (2006.01); D01D 4/02 (2006.01); D01D 5/08 (2006.01); D01D 5/088 (2006.01); D01D 5/22 (2006.01); D01D 5/253 (2006.01); D02J 13/00 (2006.01)
CPC D01F 6/62 (2013.01) [D01D 4/025 (2013.01); D01D 5/08 (2013.01); D01D 5/088 (2013.01); D01D 5/22 (2013.01); D01D 5/253 (2013.01); D02J 13/00 (2013.01); D10B 2331/04 (2013.01)] 12 Claims
 
1. A method for preparing a recycled polyester filament, comprising:
using a ring-blowing for cooling in a process of preparing a fiber from a recycled polyester according to an FDY process;
controlling a distribution of spinneret holes on a spinneret to meet certain conditions; and
obtaining the recycled polyester filament by a relaxation heat treatment after a fully drawn yarn is produced;
wherein the ring-blowing cooling has a cooling temperature of 20-25° C. and a cooling wind speed of 1.80-2.30 m/s;
wherein the spinneret holes are C-shaped spinneret holes and circular spinneret holes, a cross-section of each of the C-shaped spinneret holes is composed of an outer arc, an inner arc, and two line segments, two endpoints of the outer arc are A and B respectively, and a length of the line segment AB is greater than 0.1 mm; and
wherein the certain conditions comprise: all of the spinneret holes are distributed in concentric circles, the C-shaped spinneret holes are located on an outermost circle, and a ratio of a number of the C-shaped spinneret holes to a number of the circular spinneret holes is 70:30 to 80:20; and
while taking a straight line connecting endpoints A and B of one of the C-shaped spinneret holes as a reference line, straight lines connecting endpoints A and B of all other C-shaped spinneret holes form certain angles with the reference line, and the angles are different and are randomly distributed in a range of 0-360°.