Sundstrand Corporation

Kurt A Smith

Hossein Saatchi

Patrick J Murray

Robert E Coleman

Current processes for the formation of hybrid composite sandwich structures are expensive, often result in weak unsound products, require time and labor intensive secondary operations and are not readily adaptable for custom design work. These and other problems are solved by a relatively simple and inexpensive process producing hybrid composite sandwiched structures which includes placing core materials 24 sandwiched by multiples layers including at least one ceramic layer 46 or metallic layer 38 and having polymeric films 32, 34, 40, 42 positioned between substantially all the layers in a mold cavity 18. When the contents of the mold cavity 18 are heated to consolidate this structure, the polymeric films 32, 34, 40, 42 melt and act as an adhesive between the layers of the structure formed.

Method of forming a hybrid composite sandwich structure

Processes using high temperature thermoplastic polymers in the in-situ fabrication in the formation of foamed composite sandwich or foam articles often result in weak unsound products which may be avoided by utilizing a high temperature thermoplastic in powder form (22), a blowing agent having a high decomposition temperature (24), and, if desired, reinforcers and/or fillers, (28), mixing the thermoplastic, blowing agent and reinforcer and fillers (30), placing the mixture in a mold and, if forming a composite structure, in abutment with at least one skin (34), and applying sufficient heat and/or pressure to the mold and its contents to melt the thermoplastic and generate gas within said mixture by decomposition of the blowing agent (38). Also, an activator may be included with the blowing agent which promotes the production of gas (26). The thermoplastic should be free from any material which will react with the blowing agent or the activator at temperatures below the melting point of the thermoplastic.

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Rockford, IL, United States of America

Kurt A Smith