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Japan’s Toray Industries has developed a rapid integrated molding technology for carbon-fiber-reinforced plastic (CFRP) mobility components. This technology sandwiches a lightweight, porous carbon-fiber-reinforced foam (CFRF) core with a thermosetting prepreg skin offering outstanding mechanical properties.

This new technology makes it possible to mold CFRP mobility components such as car roofs 10 times faster than a conventional autoclave molding setup. Further, component mass is less than half that of steel counterparts. Toray intends to further R&D to accelerate the application of this technology to electric vehicle parts, where lightness and fast production are vital.

CFRP components typically sandwich urethane foam cores with thermosetting prepreg skins. Common applications for these light and rigid structures are large panels for aircraft, automobiles, ships, and infrastructure. Some have pushed for shorter manufacturing times to optimally bond the core after shaping it to the skin. In addition, vehicular electrification has made it increasingly important to reduce component weights to extend the cruising ranges of models employing heavy batteries. Emerging transportation modalities such as urban air mobility and drones also stand to benefit massively from lightweight materials.

Toray’s new rapid integrated molding technology makes it possible to fabricate large panels in a single press shot. This is because this approach simultaneously shapes, thermosets and molds, and bonds the core CFRF and thermosetting prepreg skin in the same mold.

Synchronizing the CFRF’s expansion with the prepreg’s cure timing is significantly faster than with conventional processes. The prepreg thermosetting resin penetrates the porous CFRF to bond the skin and core materials without using adhesives for a highly reliable bonding structure. Toray’s technology paves the way for the quick production of large CFRP components.

CFRF is a proprietary porous material. Its binder resin becomes flexible on heating and simultaneously expands with the restorative force of carbon fibers. The resulting three-dimensional network of short carbon fibers strongly bonds the binder resin and carbon fibers.

CFRF offers significantly better strength, elastic modulus, and impact resistance compared with conventional core materials. Its low specific 0.2–0.4 gravity range enhances performance and lightens sandwich structures.

Toray demonstrated its concept by using a pressing machine to create a large automobile roof panel (1.2 m long x 1.2 m wide x 2.3 mm thick) in just five minutes, which is 10-times faster than the conventional approach. The company assessed rigidity, coatability, sound insulation properties, and other practical aspects required for automobile production. In all-important drop-weight impact tests, Toray confirmed that the skin core interface did not delaminate, and that impact absorption is excellent.