Toho Tenax develops carbonizing process, surface treatment technologies

Tokyo, Japan – Toho Tenax Co. Ltd., the core company of the Teijin Group’s carbon fibers and composites business, has developed technologies for microwave carbonization and plasma surface treatment that are expected to help energy and CO₂ emissions saving production of automobiles, high-speed railcars, and aircraft through increased use of carbon fiber reinforced plastic (CFRP). 

 

Toho Tenax is now working to commercialize the technologies for mass production in the coming future, when CFRP is expected to be used on an increasingly large scale. For CFRP solutions broadly incorporating everything from raw materials to composite materials, the company has been placing a special emphasis on reducing production-use energy and CO₂ emissions by 50% while improving productivity.

 

Using the world’s first application of microwave energy carbonization under atmospheric pressure, Toho Tenax has achieved a tensile modulus of 240GPa or greater and rupture elongation of 1.5% or greater, both equivalent to levels found in industrial products. The advanced carbonizing process was developed by examining the fiber-structure formation process when carbonizing a bundle of between 12,000 and 24,000 pieces of flame-resistant oxidized PAN fibers, and then developing the most appropriate microwave processing method to carbonize this fibrous material. Using direct heating with microwave energy, fibrous material is carbonized continuously without having to maintain a high-temperature oven, thereby saving time and energy.

 

Toho Tenax has also succeeded in developing a carbon fiber ultra-fast plasma surface treatment technology using dry process. The highly simplified process reduces energy consumption by 50% for the whole process, compared to the conventional carbon fiber production process. In addition, the ultra-fast treatment improves the adhesiveness of carbon fiber and matrix resin.

 

The carbonizing process in the carbon fiber manufacturing process consumes large amounts of energy and produces CO2 emissions, so reductions in these areas are urgently required to facilitate large-scale mass production for automobiles and other applications.

 

Toho Tenax’s research and development programs were implemented by Japan’s New Energy and Industrial Technology Development Organization (NEDO). NEDO began promoting the research and development of innovative materials and technologies in 2014. One of the core themes of this initiative has been the research and development of core technologies for innovative carbon fiber mass-production processes for inventive CFRP applications. Toho Tenax has been participating in the project from the early stage.