Method of polycarbonate preparation
US6548623B2 · kind B2 · utility
40Cited by
2References
38Claims
0Family size
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Key dates
| Filing date | Jul 24, 2001 |
| Grant date | Apr 15, 2003 |
| Priority date | — |
| Expiry date | Jul 24, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polycarbonates containing low or undetectable levels of Fries rearrangement product may be prepared by the melt reaction of a dihydroxy aromatic compound such as bisphenol A with an ester-substituted diaryl carbonate such as the diaryl carbonate of methyl salicylate, bis-methyl salicyl carbonate. Low levels of Fries product are obtained as the combined result of a highly effective catalyst system which suppresses the Fries reaction and the use of lower melt polymerization temperatures relative to temperatures required for the analogous polymerization reaction using diphenyl carbonate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.