Negative birefringent rigid rod polymer films
US5580950A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1994 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Oct 13, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31725
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A class of soluble polymers having a rigid rod backbone, which when used to cast films, undergo a self-orientation process whereby the polymer backbone becomes more or less aligned parallel to the film surface. This in-plane orientation results in a film that displays negative birefringence. The degree of in-plane orientation and thus, the magnitude of the negative birefringence is controlled by varying the backbone linearity and rigidity of the class of polymers which includes polyesters, polyamides, poly(amide-imides) and poly(ester-imides) through selection of substituents in the polymer backbone chain. By increasing the polymer backbone linearity and rigidity, the degree of in-plane orientation and associated negative birefringence can be increased, and that conversely, by decreasing the polymer backbone linearity and rigidity, the negative birefringence can be decreased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.