The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 01, 2013
Filed:
Oct. 13, 2009
SE Hoon Kim, Daejeon, KR;
Sang Hyun Park, Daejeon, KR;
Young Koan Ko, Seoul, KR;
Lotte Chemical Corporation, Seoul, KR;
Abstract
Provided are a method for preparing fine round powdery polycarbonate and a method for preparing a high molecular weight polycarbonate resin using the same. More specifically, provided are a method for preparing fine round powdery polycarbonate, comprising (A) polymerizing non-phosgene polycarbonate, (B) extruding the polycarbonate into fine round powdery amorphous polycarbonate, (C) surface-crystallizing the fine round powdery amorphous polycarbonate in the presence of a solvent or dispersion medium, and (D) drying the surface-crystallized fine round powdery polycarbonate, and a method for preparing high molecular weight polycarbonate resin capable of obtaining polycarbonates with various molecular weights ranging from low molecular weights to high molecular weights by continuously using the obtained fine round powdery polycarbonate via a solid state polymerization step. In accordance with the methods, it is possible to remarkably simplify crystallization of amorphous polycarbonate and thus to realize process continuousness and economical efficiency enabling commercial mass-production, and to overcome production of high molecular weight polycarbonate, the most serious problem of conventional non-phosgene melt polymerization processes.