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:
Nov. 11, 1986
Filed:
Jul. 26, 1985
Constance J Araps, Wappingers Falls, NY (US);
Steven M Kandetzke, Fishkill, NY (US);
Mark A Takacs, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Acetylene or vinyl-terminated polymerizable oligomers of polyamic acid are fractionated to obtain an oligomer product having a molecular weight in the range of 2,000 to 4,000 which exhibits improved wetting and film forming properties. Fractionization is accomplished by dissolving the unfractionated polymerizable oligomer in a solvent in which the desired molecular weight fraction is soluble. The oligomer solution is passed through a filter which removes undissolved material having a molecular weight in excess of the desired molecular weight range. The filtrate is admixed with a hydrocarbon to precipitate the desired molecular weight fraction. Thereafter the collected solids can be redissolved in a ketonic solvent and the fractionation procedure repeated to further improve the molecular weight content of the fractionated oligomer.