Aromatic polyanhydride compositions
US4997904A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 25, 1989 |
| Grant date | Mar 5, 1991 |
| Priority date | — |
| Expiry date | Aug 25, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L73/02
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
Aromatic anhydride copolymers containing at least two aromatic diacid units, which are soluble in chloroform or dichloromethane to concentrations between approximately 0.5 to 50% weight/volume, melt at temperatures below 180.degree. C., and have low crystallinity are disclosed. The copolymers may contain between 0 and approximately 30% aliphatic diacid units. All copolymers are insoluble in carbon tetrachloride, i.e., less than 0.1% polymer by weight/volume solvent). The desired properties are the result of adding between 10 and 90% of a second aromatic diacid, to the copolymer composition which introduces irregularity in the polymer chains that dramatically alter the polymer properties, decreasing the crystallinity and melting point and increasing the solubility in the common solvents, dichloromethane or chloroform. An additional decrease in Tg and MP, with an increase in flexibility, is obtained by adding small amount of aliphatic diacid, up to about 30%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.