	US 12,084,542 B2
	Polycarbonate compositions with improved oxidation stability and methods of manufacturing the same
Aaron David Bojarski, Murcia (ES); and Ignacio Vic Fernandez, Murcia (ES)
Assigned to SABIC GLOBAL TECHNOLOGIES B.V., Bergen Op Zoom (NL)
Appl. No. 17/297,670
Filed by SABIC Global Technologies, B.V., Bergen op Zoom (NL)
PCT Filed Dec. 5, 2019, PCT No. PCT/IB2019/060494 § 371(c)(1), (2) Date May 27, 2021, PCT Pub. No. WO2020/115707, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 18382900 (EP), filed on Dec. 5, 2018.
Prior Publication US 2022/0041806 A1, Feb. 10, 2022
Int. Cl. C08G 64/06 (2006.01); C08G 64/30 (2006.01)

CPC C08G 64/307 (2013.01) [C08G 64/06 (2013.01)]

21 Claims

1. A method of preparing a polycarbonate composition in a polymerization system, wherein the polymerization system comprises a monomer mixing unit, the method comprising:

melt polymerizing a dihydroxy compound with a diaryl carbonate compound in the presence of a quaternary phosphonium catalyst to produce the polycarbonate composition comprising a phosphorus-containing byproduct of at least one of the quaternary phosphonium catalyst or of the diaryl carbonate compound;

recycling a recycle stream comprising the phosphorus-containing byproduct into the monomer mixing unit of the polymerization system; and

removing the polycarbonate composition from the polymerization system;

wherein the recycle stream has a phosphorus concentration of greater than or equal to 40 parts per million by weight.