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. 21, 1993
Filed:
Oct. 21, 1991
Hideo Sotokawa, Yokohama, JP;
Fusaji Shoji, Yokohama, JP;
Fumio Kataoka, Yokohama, JP;
Hidetaka Satou, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention provides a polyimide having all of small dielectric constant, small thermal expansion coefficient, high heat resistance, high glass transition temperature and high mechanical properties, a precursor of the polyimide, and processes for producing them. A polyimide precursor whose molecular chain comprises repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2): ##STR1## wherein R.sup.1 is at least one kind of tetravalent organic group selected from the group consisting of ##STR2## R.sup.2 is at least one kind of divalent organic group having a linear structure which is selected from the group consisting of ##STR3## m is an integer of 1 to 4, and R.sup.3 is a divalent organic group having a non-linear structure which contains at least two aromatic rings.