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. 06, 1994
Filed:
Jun. 18, 1993
Kaoru Kanayama, Ibaraki, JP;
Tadao Takeyama, Ibaraki, JP;
Takeshi Nakato, Ibaraki, JP;
Yoshinobu Ohnuma, Ibaraki, JP;
Hiromi Chiba, Ibaraki, JP;
Mitsubishi Petrochemical Co., Ltd., Tokyo, JP;
Abstract
A non-crystalline ether-imide type high purity bismaleimide composition represented by formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; R.sup.5 represents a hydrogen atom or a methyl group; and R.sup.6 represents a hydrogen atom, a methyl group or a phenyl group. The non-crystalline bismaleimide (I) has a purity of 95 wt % or higher, a melting point of not higher than 130.degree. C., and exhibits excellent solubility in a solvent. It is prepared by a process comprising uniformly melting a crystalline bismaleimide (I) followed by rapid cooling to solidify or a process comprising subjecting a maleamic acid, which is obtained by addition reaction between a corresponding aromatic ether diamine and maleic anhydride in an aromatic hydrocarbon/aprotic polar solvent mixed solvent, to dehydrating cyclization in the presence of an acid catalyst while azeotropically removing by-produced water with the aromatic hydrocarbon solvent, removing the remaining aromatic hydrocarbon solvent by distillation, withdrawing the produced maleimide in a molten state, and rapidly cooling to solidify.