The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 11, 2008
Filed:
Apr. 20, 2005
Motoki Okaniwa, Chuo-ku, JP;
Ichiro Kajiwara, Chuo-ku, JP;
Yoshimi Suwa, Chuo-ku, JP;
Yoichiro Maruyama, Chuo-ku, JP;
Yuichi Hashiguchi, Chuo-ku, JP;
Motoki Okaniwa, Chuo-ku, JP;
Ichiro Kajiwara, Chuo-ku, JP;
Yoshimi Suwa, Chuo-ku, JP;
Yoichiro Maruyama, Chuo-ku, JP;
Yuichi Hashiguchi, Chuo-ku, JP;
JSR Corporation, Tokyo, JP;
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.