US 12,441,839 B2
Method for producing high temperature-resistant polyamide, high temperature-resistant polyamide and use thereof
Yuanbo Zhao, Shanghai (CN); Bingbing Qin, Shanghai (CN); and Xiucai Liu, Shanghai (CN)
Assigned to Cathay Biotech Inc., Shanghai (CN); CIBT America Inc., Newark, DE (US); and Shanxi Synthetic Biology Institute Co., Ltd., Taiyuan (CN)
Filed by Cathay Biotech Inc., Shanghai (CN); CIBT America Inc., Newark, DE (US); and Shanxi Synthetic Biology Institute Co., Ltd., Taiyuan (CN)
Filed on Dec. 31, 2021, as Appl. No. 17/566,746.
Claims priority of application No. 202011201176.5 (CN), filed on Nov. 2, 2020.
Prior Publication US 2022/0306804 A1, Sep. 29, 2022
Int. Cl. C08G 69/28 (2006.01)
CPC C08G 69/28 (2013.01) 18 Claims
 
1. A process for producing a high temperature resistant polyamide, wherein the process comprises the following steps:
concentrating a polyamide salt solution, and then conducting the following operations:
(1) heating and pressurizing to a pressure of P1, and maintaining the pressure, wherein the temperature of the system is T1 at the end of the pressure-maintenance;
(2) depressurizing to a pressure of P2, wherein the temperature of the system is T2 at the end of the depressurization; and
(3) evacuating, whereby a polyamide melt is obtained;
wherein P1 is 0.8-4 MPa, T1 is 250-290° C., T1<T2 and (T2-T1)/(P1-P2)=5-75° C./MPa,
in Step (1), steam is discharged to the outside, and the ratio of the discharged steam (mol) to the water content (mol) in the polyamide salt solution is (60.6-93.9):100.