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:
Aug. 25, 2015
Filed:
Nov. 12, 2007
Tooru Murakami, Ube, JP;
Seiichirou Takabayashi, Ube, JP;
Tooru Murakami, Ube, JP;
Seiichirou Takabayashi, Ube, JP;
UBE Industries, Ltd., Ube-shi, JP;
Abstract
In a first step, a diamine is reacted with a molar excess of a tetracarboxylic dianhydride in a solvent containing more than ⅓ mole of water per mole of the tetracarboxylic dianhydride, whereby preparing a polyamic acid solution. Subsequently, in a second step, a diamine and/or a tetracarboxylic dianhydride are added to the polyamic acid solution obtained in the first step so that the molar amount of the diamine component is substantially equal to the molar amount of the tetracarboxylic acid component, and then the diamine and the tetracarboxylic dianhydride are reacted, whereby preparing a polyamic acid solution. By this process, a polyamic acid solution having a high concentration and a low viscosity may be reproducibly and reliably produced, while controlling the molecular weight of the polyamic acid to a predetermined low level.