Catalysts and methods for polymerizing macrocyclic oligomers
US7196160B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2005 |
| Grant date | Mar 27, 2007 |
| Priority date | — |
| Expiry date | Apr 20, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G2650/34
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Cyclic oligomers containing ester linkages are polymerized in the presence of a catalyst having at least one oxygen atom bonded to two metal atoms. At least one of the metal atoms is a tin atom, which is preferably tetravalent, i.e., bonded to three other groups in addition to the oxygen atom. The other metal atom may also be another tin atom, which is again preferably tetravalent, or a zinc, aluminum or titanium atom. The catalyst may contain multiple oxygen atoms that are bonded to two such metal atoms as described. These catalysts are active, efficient polymerization catalysts. They are often liquids at polymerization temperatures. The catalysts can be formed in situ in the polymerization process, which provides additional flexibility in the process and increased storage stability of starting materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.