Process for preparing aromatic carbonate polymers

• US 3,989,672 A
• Filed: 09/23/1974
• Issued: 11/02/1976
• Est. Priority Date: 10/30/1972
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Vestergaard, Jorgen Helm
• Primary Examiner(s): Briggs, Sr., Wilbert J.
• Application Number:
  US05/508,110
• Time in Patent Office: 771 Days
• Field of Search: 260/47 XA
• US Class Current: 528/199
• CPC Class Codes: C08G 64/24 and phenols

Abstract

A process for preparing a polycarbonate having improved resistance to thermal degradation and improved impact resistance by reacting a carbonate precursor such as phosgene with a dihydric phenol such as bisphenol-A in an aqueous medium while adding sufficient alkali metal hydroxide to maintain a pH of between 8.0 and 10.2 during the entire reaction.

Claims

1. A process for preparing a carbonate polymer having improved resistance to thermal degradation and improved impact resistance, which process consists of reacting a carbonate precursor with 2,2-bis(4-hydroxyphenyl) propane in an aqueous medium containing sufficient alkali metal hydroxide to maintain a pH between 8.0-10.2 during the reaction.

2. The process of claim 1 which consists of (a) mixing 2,2-bis(4-hydroxyphenyl) propane in an aqueous medium containing a solvent for the carbonate polymer, a molecular weight regulator and a catalyst, (b) introducing a carbonyl halide into the reaction medium and (c) adding simultaneously with the carbonyl halide sufficient alkali metal hydroxide to maintain a pH between 8.0 and 10.2.

3. The process of claim 2 wherein the carbonyl halide is phosgene.

4. The process of claim 2 wherein the alkali metal hydroxide is sodium hydroxide.

5. The process of claim 2 wherein the catalyst is triethylamine.