Cellulose ester compositions having low birefringence and films made therefrom
US8710214B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 2009 |
| Grant date | Apr 29, 2014 |
| Priority date | — |
| Expiry date | Dec 10, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2301/14
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention relates to cellulose esters having low hydroxyl content for use in optical applications, such as liquid crystal display (LCD) films. Films made with low hydroxyl levels and a given ratio of non-acetyl ester to hydroxyl level have been found to have low intrinsic birefringence. These films can be cast, molded, or otherwise oriented without an appreciable birefringence or optical distortion (i.e. retardation). Such features make these films useful in polarizer, protective, and compensator films as well as molded optical parts, such as lenses. Furthermore, it has also been found that resins of the present invention can also be made to have “+C plate” behavior either by melt or solvent based processing, a characteristic which is not typical of cellulose esters. Such +C behavior allows films to be produced having unique compensatory behavior. Other embodiments of the invention relate to methods melt casting films while minimizing birefringence formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.