Process for the purification of polycarbonate and polyester carbonate solutions

• US 5,420,241 A
• Filed: 04/07/1994
• Issued: 05/30/1995
• Est. Priority Date: 04/16/1993
• Status: Expired

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Ooms, Pieter, Pakull, Ralf, Fennhoff, Gerhard, Buysch, Hans-Josef
• Primary Examiner(s): Kight, III, John
• Assistant Examiner(s): BOYKIN, TERRESSA M
• Application Number:
  US08/224,455
• Time in Patent Office: 418 Days
• Field of Search: 528/490, 528/480, 528/198
• US Class Current: 528/490
• CPC Class Codes: C08G 63/90 Purification; Drying
• CPC Class Codes: C08G 64/406 Purifying; Drying

Abstract

A process for purifying aromatic carbonate polymers, including polycarbonates and polyestercarbonates, is disclosed. Accordingly a carbonate polymer in an organic solvent is rendered virtually free of low molecular weight components by agitation with aluminosilicate or by passing through layers of such aluminosilicate. The aluminosilicate is subsequently separated off and the carbonate polymer is isolated in known methods.

Claims

1. A process for the purification of a solution of an aromatic carbonate polymer comprising

(i) combining said solution with aluminosilicate,

(ii) filtering said solution to separate said aluminosilicate, and

(iii) isolating the carbonate polymer, said carbonate polymer being at least one member selected from the group consisting of polycarbonate and polyester carbonate having a weight average molecular weight of about 10,000 to 200,000, said combining consisting of one of (a) agitating and (b) passing through at least one layer of said aluminosilicate, said solution containing about 1 to 30 percent relative to its weight of said carbonate polymer, said purification being carried out at temperatures between 10°

and 110°

C. under pressure of 0 to 10 bar and at a reaction time of 3 to 600 minutes, said purification denoting the virtual freeing of said solution from organic constituents having low molecular weights.

2. The process of claim 1 wherein combining consists of agitating said solution with aluminosilicate.

3. The process of claim 1 wherein said combining consists of passing said solution through at least one layer of aluminosilicate.

4. The polycarbonate prepared in accordance with the process of claim 1.

5. The polyester carbonate prepared in accordance with the process of claim 1.

6. The mixture of polycarbonate and polyester carbonate prepared in accordance with the process of claim 1.

7. The process of claim 1 wherein said aluminosilicate is a zeolite.

8. The process of claim 1 wherein said aluminosilicate is a sheet silicate or pillard clay.

9. The process of claim 1 wherein said aluminosilicate is a member relected from kaolin types, serpentine types and montmorillonite types.

10. The process of claim 1 wherein said aluminosilicate is present at an amount of about 0.1 gram to 100 gram per 1 liter of polycarbonate solution.

11. The process of claim 10 wherein said aluminosilicate is present at an amount of about 1 gram to 20 gram per 1 liter of polycarbonate solution.