Polyimide foam filled structures

US5188879A · kind A · utility

Assignee

• Sorrento Engineering Corporation · US

Inventors

• Francis U. Hill · San Diego, US
• Paul F. Schoenzart · Leverkusen, DE
• Werner Frank · Bensberg, DE

Key dates

• Filing date: Jul 15, 1991
• Grant date: Feb 23, 1993
• Expiry date: Jul 15, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/249958
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

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.