Claims
- 1. A process for preparing a block oligocarbonate selected from the group consisting of ##STR24## where R denotes ##STR25## and where A denotes an aromatic carbonate structure conforming to ##STR26## where n is 2-6, B is the residue of an aliphatic polyol, with the proviso that said B is bonded to said A through the terminal carboxyl in said A, and where Ar denotes an aromatic radical derived from the group consisting of ##STR27## where A' denotes an C.sub.1-8 alkylene group, C.sub.2-8 alkylidene group, C.sub.5-15 cycloalkylene group, C.sub.5-15 cycloalkylidene group, carbonyl group, an oxygen atom, a sulfur atom, -SO-, -SO.sub.2 - or a radical conforming to ##STR28## e and g denote 0 or 1, Z independently denotes F, Cl, Br or C.sub.1-4 -alkyl, d is an integer of 0 to 4 and f is an integer of 0 to 3, comprising
- a) reacting an aromatic polycarbonate with an aliphatic polyol and
- b) reacting the product of said a) with diphenyl carbonate,
- characterized in that said a) is carried out in the melt at a temperature of 180.degree.-230.degree. C. in the presence of a transesterification catalyst and said polycarbonate having a weight average molecular weight of about 10,000 to 20,000, and where said aliphatic polyol has a molecular weight of up to about 30,000 and a functionality of 1 to 6.
- 2. The process of claim 1 wherein diphenyl carbonate is reacted at a stoichiometrically equivalent amount.
- 3. The process of claim 1 wherein diphenyl carbonate is reacted at less than a stoichiometrically equivalent amount.
- 4. The oligocarbonate produced by the process of claim 1.
- 5. The oligocarbonate produced by the process of claim 2.
- 6. The oligocarbonate produced by the process of claim 3.
- 7. The process of claim 1 wherein aliphatic polyol is polyether polyol.
- 8. The process of claim 1 wherein said aliphatic polyol has a molecular weight of about 1500 to 4000.
- 9. The process of claim 1 wherein said aliphatic polyol has a molecular weight of about 6000 to 10,000.
- 10. The block oligomer produced by the process of claim 7.
- 11. The block oligomer produced by the process of claim 8.
- 12. The block oligomer produced by the process of claim 9.
Parent Case Info
This application is a continuation of Ser. No. 965,128, which was filed on Oct. 22, 1992 now abandoned, which in turn is a continuation-in-part Ser. No. 07/802,677 filed on Dec. 4, 1991, now abandoned.
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Continuations (1)
|
Number |
Date |
Country |
Parent |
965128 |
Oct 1992 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
802677 |
Dec 1991 |
|