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:
Feb. 23, 1993
Filed:
Jul. 15, 1991
Francis U Hill, San Diego, CA (US);
Paul F Schoenzart, Leverkusen, DE;
Werner P Frank, Bergisch Gladbach, DE;
Sorrento Engineering Corporation, National City, CA (US);
Abstract
A method of manufacturing polyimide foam filled structures such as honeycomb panels. A polyimide foam precursor is prepared in powder form. A layer of the powder is heated and foamed at the resin condensation temperature and pre-cured to an easily handleable, stiff and inflexible state. A multi-cell, thin-walled structure having open cells along a surface is pressed into and through the foam sheet so that foam pieces fill the cells. The foam is then heated to a final cure temperature at which the foam becomes stable, resilient and flexible. Face sheets may be bonded to the structure to retain the foam pieces in the cells. If desired, the walls of the structure that contact the foam may be coated with an adhesive, such as a liquid polyimide adhesive resin precursor, so that the foam will be bonded to the cell walls when the liquid resin precursor is cured as a necessary result of the final foam cure conditions.