Cyclic polycarbonate oligomers: inhibition and control of polymerization to linear polycarbonates
US4816548A · kind A · utility
30Cited by
1References
10Claims
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Key dates
| Filing date | Aug 24, 1987 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Aug 24, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/30
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Lewis acids such as triphenyl borate, triphenylborane and aluminum isopropoxide are employed to inhibit or control the formation of linear polycarbonates from cyclic polycarbonate oligomers. Inhibition of polymerization initiated by impurities in the cyclics is noted. When polymerization is effected by basic polycarbonate formation catalysts, the Lewis acids can act as reaction rate accelerators or inhibitors depending on reaction parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.