Cycloolefin copolymer obtained by ring-opening polymerization, use thereof, and process for producing retardation plate comprising the copolymer
US7449532B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2005 |
| Grant date | Nov 11, 2008 |
| Priority date | — |
| Expiry date | Jul 26, 2025 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2023/38
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A cycloolefin copolymer obtained by ring opening polymerization according to the present invention is characterized by comprising a specific structural unit and exhibiting a single peak in a derivative differential scanning calorimetry curve obtained by differential scanning calorimeter (DSC), having a temperature width of the rising part in the peak of 35° C. or below, and having a glass transition temperature (Tg) of 110° C. or above. The cycloolefin copolymer provided by the present invention has excellent heat resistance and optical properties, is suitable for the formation of a film or sheet therefrom, and can be stretched even at a relatively low temperature around the Tg without causing troubles such as cloudiness. A film or sheet comprising the cycloolefin copolymer, which has excellent optical properties and heat resistance and is also suitable for stretching even at a relatively low temperature, is also provided. Further, there are also provided a retardation plate having excellent optical properties and heat resistance and having uniform retardation, and a process for producing the retardation plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.