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:
Apr. 27, 1993
Filed:
May. 07, 1991
Sumitomo Bakelite Company Limited, Tokyo, JP;
Abstract
The present invention provides an oligomer having an inherent viscosity .eta. of 0.001-0.5 dl/g as measured at a concentration of 0.5 g/dl in N-methyl-2-pyrrolidone at 30.degree. C., which has been obtained by subjecting to polymerization and imidization (a) an acid component consisting of an aromatic tetracarboxylic acid dianhydride and/or a derivative thereof and (b) a diamine component consisting of 5-100 mole % of a diaminosiloxane represented by the undermentioned formula (I) and 95-0 mole % of an organic diamine other than the formula (I): ##STR1## wherein R.sub.1 is a divalent aliphatic group of 1-5 carbon atoms or a divalent aromatic group of 6 or more carbon atoms; R.sub.2 and R.sub.3 are each a monovalent aliphatic or aromatic group and may be the same or different; and m is an integer of 1-100, as well as an oligomer solution obtained by dissolving the above oligomer in an organic solvent.