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# c12) United States Patent 

# Fischer et al. 

# (54) PROCESS FOR THE PREPARATION OF POLYCARBONATE BY THE MELT TRANSESTERIFICATION PROCESS 

(75) Inventors: Pete Fischer, Cologne (DE); Wilfried Haese, Odenthal (DE); Alexander Meyer, Duesseldorf (DE) 

(73) Assignee: Bayer MaterialScience AG, Leverkusen (DE) 

( *) Notice: Subject to any disclaimer, the term ofthis patent is extended or adjusted under 35 U.S.C. 154(b) by O days. 

(21) Appl. No.: 12/117, 798 

(22) Filed: May 9, 2008 

## (65) Prior Publication Data 

US 2008/0319156Al Dec. 25, 2008 

## (30) Foreign Application Priority Data 

May 11, 2007 (DE) ....................... 10 2007 022 130 

(51) Int. Cl. C0SG 64100 (2006.01) C08G 63/02 (2006.01) 

(52) U.S. Cl. ...................... 28/196; 264/176.1; 264/219; 264/328.1; 428/64.4; 428/451; 524/91; 524/154; 524/306; 524/317; 524/451; 524/611; 528/198 

(58) Field of Classification Search .............. 264/176.1, 264/219, 328.1; 428/64.4; 524/91, 154, 524/306, 317,451, 611; 525/155, 156, 462; 528/196, 198 See application file for complete search history. 

## (56) References Cited 

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## U.S. PATENT DOCUMENTS 

<img src='content_image/924434.jpg'>

# (10) Patent No.: US 7,814,626 B2 

# (45) Date of Patent: Oct. 19, 2010 

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## FOREIGN PATENT DOCUMENTS 

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* cited by examiner 

Primary Examiner-Terressa M Boykin 

(7 4 )Attorney, Agent, or Firm----Connolly Bove Lodge & Hutz LLP 

## (57) ABSTRACT 

The invention provides a process for the preparation of poly› carbonate by the melt transesterification process, polycarbon› ate having a low electrostatic charge obtainable by this pro› cess, and moldings or extrudates, in particular optical data storage media or light-diffusing plates, made from this poly› carbonate. 

US007814626B2 

## 20 Claims, No Drawings 

