Sundstrand Corporation

Hossein Saatchi

John F Scanlon

David W Okey

John S Church

Kurt A Smith

Gary A Wigell

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), admixing the thermoplastic, blowing agent and reinforcer and fillers (30), placing the admixture in a mold and, if forming a composite structure, in abutment with at least one skin (34), compacting the contents of the mold (37), 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. Articles made by the process are also disclosed.

Method of in-situ fabrication of foamed thermoplastic articles and

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.

Enhanced foaming of thermoplastics for in-situ fabrication of advanced

A method of fabricating a composite structure having at least one skin molecularly bonded to a core. A skin is provided of reinforcing fibrous material and a thermoplastic matrix. The skin is thermoformed to the general exterior shape of the composite structure. A core having a thermoplastic matrix complementary to the matrix of the skin is molded into the general shape of the composite structure. The skin and the core are placed in juxtaposition in a final forming mold. A thermoplastic material is injected into the final forming mold under isostatic conditions. The thermoplastic material is complementary to the thermoplastic matrices of the skin and the core.

Method of fabricating composite structures

A method of fabricating a composite structure having at least one skin molecularly bonded to a core. A skin is provided of reinforcing fibrous material and a thermoplastic matrix. The skin is thermoformed to the general exterior shape of the composite strucutre. The skin is placed in a mold, and a core material is injected into the mold against the skin under isostatic conditions. The core material includes a thermoplastic matrix compatible to the thermoplastic matrix of the skin to form a molecular bond therewith.

A composition for a pressure molded core of a composite structure, including a thermal plastic resin. The composition also includes a component to reduce the coefficient of thermal expansion, a lightweight high compressive strength filler, and a blowing agent. The thermoplastic resin may be polyetheretherketone, the component may be carbon fibers, and the filler may be hollow glass microspheres.

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Rockford, IL, United States of America

Hossein Saatchi