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:
Dec. 23, 2025
Filed:
Mar. 26, 2021
Unitika Ltd., Osaka, JP;
Nippon Ester Co., Ltd., Okazaki, JP;
Unitika Trading Co., Ltd., Osaka, JP;
UNITIKA LTD., Osaka, JP;
Abstract
To provide a biaxially stretched polyester resin film that has excellent properties equal to or better than those of biaxially stretched polyester film that does not use recycled raw material, and in particular that has an excellent flexural resistance in low-temperature environments. A biaxially stretched polyester resin film that characteristically satisfies both of the following properties (1) and (2): (1) in differential scanning calorimetry (DSC), after heating from 25° C. to 300° C. at a heating rate of 20° C./minute and holding for 10 minutes at 300° C., the temperature of crystallization during cooling at a cooling rate of 40° C./minute is 160° C. to 180° C.; and (2) the number of pinholes after the execution of 200 repetitive cycles of a flexural fatigue test in a −10° C. atmosphere using a Gelbo Flex Tester is not more than 10/500 cm.