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:
Jul. 16, 2013
Filed:
Aug. 30, 2012
Naoya Kutsuzawa, Yokosuka, JP;
Naoya Kutsuzawa, Yokosuka, JP;
Toho Chemical Industry Co., Ltd., Tokyo, JP;
Abstract
The present invention provides a method for producing a polybenzoxazole precursor having reduced contents of residual aprotic polar solvent and residual halogen without discharging a large amount of waste water during purification. The present invention specifically relates to a method for producing a polybenzoxazole precursor, which comprises synthesizing a polybenzoxazole precursor in an aprotic polar solvent, adding and mixing water and a water-insoluble solvent with the resulting polybenzoxazole precursor solution to still stand the solution, and then separating a water layer from the solution to reduce a content of impurities remaining in the polybenzoxazole precursor.